description stringlengths 2.98k 3.35M | abstract stringlengths 94 10.6k | cpc int64 0 8 |
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CROSS REFERENCE TO RELATED APPLICATION
This application is a divisional of U.S. application Ser. No. 13/924,302, filed on Jun. 21, 2013, and titled “Auxiliary Power Supplies,” which is incorporated herein by reference.
TECHNICAL FIELD
The invention relates to auxiliary power supplies.
BACKGROUND OF THE INVENTION
Switching regulators for the conversion of electrical power are well known. Such switching regulators generally include various control circuits. Some circuits may be quite simple, such as a gate driver, others may be quite complex, such as the main control circuit.
Invariably, a control circuit requires a supply of power of its own. A supply for control circuits commonly goes by a name such as auxiliary supply, housekeeping supply, bias supply, VDD supply or VCC supply.
An auxiliary supply by itself requires a supply of current for operation. There is a general need for circuits providing the supply of current at lowest cost, smallest circuit size and highest efficiency.
A wide variety of circuits for the supply of current exist.
The suitability of some circuits depends on the operational stage of the switching regulator, the two states of main concern being the nonswitching or startup stage and the switching or running stage of switching regulator operation. The switching stage can be characterized by the stage of operation where control circuits are being prepared for switching operation of the switching regulator. The switching stage can be characterized by the stage where switching operation of the switching regulator is in place. Accordingly, some circuits are particularly suited to the nonswitching stage of switching regulator operation, whereas other circuits are particularly suited to the switching stage of switching regulator operation.
The suitability of some circuits depends on the configuration of the control circuit and its associated auxiliary supply within a switching regulator. Typically, a control circuit and its associated auxiliary supply are configured with a node in common. The potential at the common node may be broadly categorized as being one of two types, a steady voltage or a switching voltage. For instance, the main control circuit of a switching regulator and its associated auxiliary supply are typically configured with a common node carrying a steady potential. A gate driver of a floating switch within a switching regulator and its associated auxiliary supply are frequently configured with a common node carrying a switching potential. Accordingly, some circuits are particularly suited to a configuration with a common node carrying a steady potential. Other circuits are particularly suited to a configuration with a common node carrying a switching potential.
Among the more common circuits of the prior art for the supply of current is the supply by way of a resistor or a linear regulator, the supply by way of various transformer based techniques, and the supply by way of various switched capacitor techniques.
The supply of current by way of a resistor or a linear regulator is simple and low cost. This method is typically suited to the supply of current in both the nonswitching and switching stages of switching regulator operation, and is frequently suited to the supply of current for a configuration where the common node carries either a steady or a switching potential. The major drawback is the dissipation of power within the resistor or linear regulator. The dissipation becomes prohibitively large in offline switching regulators, thus requiring the use of other circuit solutions for the supply of current.
The supply of current by way of transformer techniques is more complicated but provides a supply of current with relatively high efficiency. This method typically relies on the switching operation of the switching regulator, and, therefore, is typically suited to the switching stage of switching regulator operation only. The method is generally suited to configurations where the common node carries either a steady or a switching voltage. A common drawback is a dependence of the auxiliary supply voltage on operating conditions of the switching regulator, such as loading, input voltage, or output voltage, the dependence at times requiring additional voltage regulation circuitry.
The supply of current by way of various switched capacitor techniques is generally low cost and efficient. A common configuration is the bootstrap supply. The bootstrap technique is typically suited to the switching stage of switching regulator operation only. The method is generally suited to configurations where the common node carries a switching voltage only.
What is needed is a circuit for the supply of current to an auxiliary supply that is suitable for use during the nonswitching and switching stages of switching regulator operation, and that is suitable for configurations with a common node carrying either steady or switching potential, and that has minimal power dissipation.
SUMMARY OF THE INVENTION
The following discloses an invention suited to the supply of current to an auxiliary supply, where the auxiliary supply is connected in parallel with a switch of a switching regulator.
An auxiliary supply of a switching regulator frequently shares a common node with a switch of the switching regulator. Such an auxiliary supply can be connected in parallel with the switch by adding a second connection at the switch of the switching regulator.
By virtue of the connection in parallel a supply of current to the auxiliary supply is available when the switch is off. A switch and a diode are included within the connection to the auxiliary supply. The switch within the connection, hereafter the auxiliary supply switch, provides positive control over the flow of current to the auxiliary supply, that is, the auxiliary supply switch enables a flow of current to the auxiliary supply when the auxiliary supply switch is on and the switch in parallel is off. The diode within the connection, hereafter the auxiliary diode, prevents a reverse flow of current, from the auxiliary supply towards the switch, when the switch in parallel is on. The auxiliary diode is not required if the auxiliary supply switch is of a type that inherently blocks reverse current flow.
Embodiments of the circuit for the supply of current according to the present invention are characterized by low component count, are suitable to the supply of current in both stages of switching regulator operation, are suitable to configurations with a common node carrying either type of potential, steady or switching, provide the supply of current at exceptionally high efficiency in the switching stage of switching regulator operation, and provide this high efficiency over a wide range of operating conditions of the switching regulator.
The strategy for the control of the auxiliary supply switch can be manifold.
The auxiliary supply switch may be operated advantageously in both the linear region and the saturation region, or stated otherwise, may be operated advantageously as a device of significant impedance and a device of negligible impedance.
The choice of operating mode is, at least in part, determined by the operational stage of the switching regulator.
In the nonswitching stage of switching regulator operation the auxiliary supply switch may be advantageously operated as a device of significant impedance so as to power up the auxiliary supply and associated control circuits gradually, and so as to suppress the flow of large or oscillatory currents which may cause damage or create interference.
In the switching stage of switching regulator operation the auxiliary supply switch is advantageously operated as a device of negligible impedance so as to provide the desired supply of current to an auxiliary supply at highest efficiency, that is, without causing undue dissipation within the path for the supply of current.
The auxiliary supply switch is preferably closed in a part of the switching cycle which results in the lowest stress for the auxiliary supply switch and auxiliary diode.
Lowest stress for the auxiliary diode and auxiliary switch can generally be expected to occur in the parts of the switching cycle where the lowest stress for the switch of the switching regulator occurs. In general, the waveform of a switch current may be either a rising current waveform or a falling current waveform. Switches which conduct during the on time of a switching cycle generally carry a rising current, whereas switches which conduct during off time of a switching cycle generally carry a falling current. Accordingly, in a situation where the switch of the switching regulator conducts during the on time period, the auxiliary supply switch of an auxiliary supply is preferably closed towards the start of the on time period, and in a situation where the switch of the switching regulator conducts during the off time period, the auxiliary supply switch of an auxiliary supply is preferably closed towards the end of the off time period.
The connection of an auxiliary supply in parallel to a switch of the switching regulator according to the present invention is particularly advantageous where the switch of the switching regulator is implemented as a cascode switch. Here, the parallel connection of the auxiliary supply to the switch is made advantageously at the low voltage switch of the cascode switch. Such a configuration allows the voltage rating of the auxiliary supply switch to be essentially as low as the voltage rating of the low voltage switch, thereby making the auxiliary supply switch amenable to integration within power management integrated circuits (IC) built on a low voltage process.
Other aspects and advantages of the present invention will become apparent from the following detailed description, taken in combination with the accompanying drawings, illustrating by way of example the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 depicts an exemplary embodiment of a buck regulator.
FIG. 2 depicts current waveforms of the exemplary buck regulator.
FIG. 3 depicts current waveforms of the exemplary buck regulator.
FIG. 4 depicts an exemplary embodiment of a boost regulator.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
A first exemplary embodiment employs the principles of the invention in the setting of a buck regulator, specifically of the type where the switch, the associated gate driver circuit and associated auxiliary supply are configured with a common node carrying a switching potential.
The principles of the invention are applied to the supply of current to the auxiliary supply of the gate driver circuit. This particular embodiment exemplifies the use of the invention where the supply of current is provided in both the nonswitching and switching stages of buck regulator operation and where the common node carries a switching potential.
FIG. 1 depicts the exemplary buck regulator 10 . Switch 100 is of the FET type. The source of the FET, is connected to node 101 , commonly known as the switching node. Switch 100 is driven by gate driver circuit 110 at gate 102 of FET 100 , the gate driver circuit also connected to node 101 . Auxiliary supply 200 powers gate driver circuit 110 , the auxiliary supply also connected to node 101 .
By virtue of circuit configuration, auxiliary supply 200 and switch 100 in parallel share node 101 in common, node 101 being the switching node. The switching node carries a switching potential in the switching stage of buck regulator operation.
According to the principles of the current invention, auxiliary supply 200 is connected in parallel with switch 100 by a second connection which includes auxiliary diode 210 and auxiliary supply switch 220 , the second connection providing a supply of current to input node 230 of auxiliary supply 200 .
Furthermore, in FIG. 1 are shown capacitor 240 , auxiliary control circuit 250 and main control circuit 400 .
Capacitor 240 is connected between input node 230 and common node 101 . Capacitor 240 , hereafter the auxiliary capacitor, is provided to the extent that attenuation of voltage variation at input node 230 is required. An auxiliary capacitor is typically required to accommodate an intermittent delivery of current by way of the parallel connection and to accommodate an intermittent or irregular draw of current of the control circuit, here gate driver circuit 110 .
Auxiliary supply control circuit 250 is connected to input node 230 in order to receive power and to sense the voltage at input node 230 . Control circuit 250 controls auxiliary supply switch 220 for purpose of regulating the voltage at input node 230 . Control circuit 250 may provide other control functions as well such as communication with main control circuit 400 .
Main control circuit 400 provides control functions typical of a buck regulator, such as output voltage control, pulse width modulation, start up coordination, monitoring and protection. Main control circuit 400 interacts with gate driver 110 .
By way of illustration, auxiliary supply switch 220 can be operated in the following manner.
In the nonswitching stage of buck regulator operation, auxiliary supply switch 220 is operated as a device of significant impedance. Auxiliary switch 220 is to be arranged as a switch of the normally on type, for example, as a depletion FET. A depletion FET is capable of conducting current when auxiliary supply 200 is in a nonenergized state. A resistor, not shown in the figure, may be included in the path of auxiliary supply switch 220 for control of current amplitude.
Upon first application of power, as provided by voltage source 300 , current flows by way of (a) auxiliary diode 210 , (b) auxiliary supply switch 220 , (c) input node 230 , (d) auxiliary capacitor 240 , (e) common node 101 , (f) inductor 310 , and (g) load 320 , here depicted as a resistor. As a consequence, the voltage on auxiliary capacitor 240 rises gradually. The impedance of auxiliary supply switch 220 can be adjusted such that the current is of relatively small amplitude for purpose of keeping the size of auxiliary diode 210 and switch 220 small and to prevent oscillation. The impedance provides damping for a circuit which generally contains many modes of oscillation as provided by the presence of inductors and capacitors attached to the path of current flow, such as auxiliary capacitor 240 , inductor 310 , and input and output filter components.
Auxiliary control circuit 250 regulates the voltage at input node 230 by control of auxiliary supply switch 220 in the manner of a series regulator. Many methods of control exist in the prior art for the control of a voltage by means of a series regulator.
The voltage on input node 230 and elsewhere within the auxiliary control circuit 250 ultimately rises to a level which supports regular operation of gate driver 110 . Control circuit 250 , or gate driver circuit 110 , may then signal to main control circuit 400 that gate driver 110 is ready for switching operation. Buck regulator operation may then transition from the nonswitching stage to the switching stage depending on the readiness of other parts within buck regulator 10 .
In the switching stage of buck regulator operation, auxiliary supply switch 220 is operated as a device of negligible impedance.
Many variations for implementation of the auxiliary switch exist. Auxiliary supply switch 220 may be arranged as a single device, or as two devices in parallel, a first device specifically adapted for the supply of current during the nonswitching stage of switching regulator operation, and a second device specifically adapted for the switching stage of switching regulator operation. The first device may be a normally on device or a normally off device biased for conduction when auxiliary control circuit 250 is not operational during the nonswitching stage of switching regulator operation.
Auxiliary control circuit 250 regulates the voltage at input node 230 by control of auxiliary supply switch 220 in the manner of a switching regulator. Auxiliary control circuit 250 may close auxiliary supply switch 220 during any part or for any duration of a switching cycle.
The method of control of auxiliary supply switch 220 in the switching stage of buck regulator operation can be manifold.
Auxiliary control circuit 250 adjusts the period of conduction of auxiliary supply switch 220 for purpose of controlling the voltage at input node 230 . Many methods for the control of a voltage by means of pulse width modulation and feedback control are known in the art, which can be employed for this purpose.
FIGS. 2 and 3 depict exemplary current waveforms of buck regulator 10 operating in steady state mode. The Figures illustrate current waveforms corresponding with the switching stage of switching regulator operation for two modes of pulse width modulation. The following current waveforms are shown: (a) waveform 501 representing the current of inductor 310 , (b) waveform 502 representing current of auxiliary supply 200 and switch 100 combined, (c) waveform 503 representing the supply of current to auxiliary supply 200 , (d) waveform 504 representing the current of switch 100 , and (e) waveform 505 representing the average supply of current to auxiliary supply 200 . Waveform 502 equally represents the current of the source 300 and the current of inductor 310 during the on time period of the switching cycle.
Without loss of generality, buck regulator 10 is shown to operate in the continuous conduction mode. The current waveforms of FIG. 2 correspond to a control mode where auxiliary supply switch 220 closes at the start of the switching cycle, or stated alternatively, at the start of the on time period. The current waveforms of FIG. 3 correspond to a control mode where auxiliary supply switch 220 closes with a certain delay after the start of the on time period.
Both figures depict waveforms that result in a supply of current having the same average current. Whereas the average current stress for auxiliary diode and auxiliary supply switch 220 is the same for both figures, a significantly lower peak current stress is attained with the control mode of FIG. 2 . Hence, the control mode of FIG. 2 is generally preferable over the control mode of FIG. 3 .
It can be generally stated that a switch of a switching regulator carries a rising current if the switch closes during the on time period of a switching cycle, and that a switch of a switching regulator carries a falling current if the switch closes during the off time period of a switching cycle. Accordingly, the supply of current is preferably arranged for the start of the on time period for an auxiliary supply in parallel with a switch which closes during the on time period of a switching cycle, and the supply of current is preferably arranged for the end of the off time period for an auxiliary supply in parallel with a switch which closes during the off time period of a switching cycle.
The supply of current at the start of the on time period or at the end of the off time period is particularly advantageous for a switching regulator operating in the discontinuous mode of operation, where the switch and auxiliary supply switch currents are particularly small, that is, near zero, near the start of the on time period and near the end of the off time period.
It is shown in FIGS. 2 and 3 that the closing of auxiliary supply switch 220 is interlaced with the closing of switch 100 . The supply of current by way of auxiliary supply switch 220 requires that switch 100 is open for the duration of the supply of current. Accordingly, auxiliary control circuit 250 provides inhibit signal 251 to gate driver 110 to hold off the closure of switch 100 during the supply of current to the auxiliary supply.
The control of the supply of current according to the waveforms of FIGS. 2 and 3 may be accomplished in practice in at least two manners. In a first manner, auxiliary supply switch 220 and switch 100 truly receive complementary control signals, that is to say, auxiliary supply switch 220 is commanded on when switch 100 is commanded off, and vice versa. In a second manner, auxiliary supply switch 220 is commanded on for the full duration of the on time period and switch 100 is operated for control of the supply of current, enabling flow of current to the auxiliary supply when switch 100 is commanded off and disabling the flow of current to the auxiliary supply when switch 100 is commanded on. The second manner offers an advantage in that practical complications with the implementation of true complementary switching can be avoided.
A second exemplary embodiment employs the principles of the invention in the setting of a boost regulator, specifically of the type where the switch of the switching regulator is embodied as a cascode switch, and where the common node carries a steady potential.
The use of a cascode switch as a switch of a switching regulator allows integration of the auxiliary switch and other parts of the auxiliary supply with other control circuits within an integrated circuit of low voltage rating. Furthermore, the second embodiment highlights that the common node may equally carry a steady voltage.
FIG. 4 depicts the exemplary boost regulator 20 . Switch 500 is of the cascode type. The use of a cascode switch is well known in the art. The cascode switch offers a number of advantages, such as a lower gate drive requirement and faster, more efficient switching.
A cascode switch consists of the series connection of two devices, functionally operating as a single switch, where the source and gate terminals of the cascode switch corresponds with the like terminals of the low voltage device and the drain terminal of the cascode switch corresponds to the like terminal of the high voltage device. One of ordinary skill in the art will appreciate that the designations of low voltage and high voltage as used in low voltage device and high voltage device indicate the relative voltage ratings of the devices as frequently encountered in applications of a cascode switch, and will recognize that the principles of the invention apply regardless of the relative ratings of the two devices and that the designations are used for purpose of identification only.
Many variations exist in the art for the choice of the individual devices, the low voltage device typically being a low voltage enhancement FET, and the high voltage device typically being a high voltage enhancement FET, a high voltage depletion FET, or a high voltage BJT.
FIG. 4 shows a variation of cascode switch 500 , based on a series connection of two enhancement FETs. High voltage device 520 is permanently biased for conduction at gate 522 by shunt regulator 525 , whereas low voltage device 510 is controlled at gate 512 for control of the cascode switch 500 .
In FIG. 4 , the source of switch 500 , here equivalent to the source of low voltage device 510 , is connected to node 101 , as is gate driver circuit 110 , main control circuit 400 , and auxiliary supply 200 . Items labeled with the same numbers shown in FIG. 1 perform the same function described previously for FIG. 1 .
By virtue of circuit configuration, auxiliary supply 200 and switch 500 in parallel share node 101 in common, node 101 being the return or ground node. This embodiment is an example of a configuration where the common node carries a steady potential.
According to the principles of the invention, auxiliary supply 200 is connected in parallel with low voltage device 510 of cascode switch 500 by a second connection which includes auxiliary diode 210 and auxiliary supply switch 220 , the second connection providing a supply of current to input node 230 of auxiliary supply 200 .
By way of illustration, auxiliary supply switch 220 can be operated in the following manner.
In the nonswitching stage of boost regulator operation, auxiliary supply switch 220 is operated as a device of significant impedance.
Upon first application of power, as provided by voltage source 300 , current flows by way of (a) inductor 310 , (b) high voltage device 520 , (c) auxiliary diode 210 , (d) auxiliary supply switch 220 , (e) input node 230 , (f) auxiliary capacitor 240 , and (g) common node 101 .
The supply of current causes the voltage on input node 230 to rise. Auxiliary control circuit 250 regulates the voltage at input node 230 by control of auxiliary supply switch 220 in the manner of a series regulator as before. High voltage device 520 , being permanently biased for conduction is operated as part of the linear regulator.
The voltage on input node 230 and other parts ultimately rises to a level which supports switching operation of boost regulator 20 . A transition from the nonswitching stage to the switching stage of boost regulator operation occurs depending on the readiness of other parts within boost regulator 20 .
In the switching stage of buck regulator operation, auxiliary supply switch 220 is operated as a device of negligible impedance. All considerations provided in the description of buck regulator 10 apply equally well for the boost regulator 20 described here. This includes the operation of auxiliary supply switch 220 and switch 100 , switch 100 embodied as cascode switch 500 . The current waveforms of FIGS. 2 and 3 apply equally to boost regulator 20 , where current waveform 504 is to be understood as the current of low voltage device 510 , whereas the current of high voltage device 510 is represented by current waveform 502 .
Of particular advantage is the low operating voltage of the low voltage device 510 and, by extension, the low operating voltage of auxiliary diode 210 and auxiliary supply switch 220 . Most, if not all parts enclosed by boundary 600 , with the possible exception of auxiliary capacitor 240 , can be selected for integration into a single integrated circuit manufactured on a low voltage process.
Although the embodiments described above involved a boost regulator or buck regulator, one of ordinary skill in the art will understand that the inventions can apply to all types of regulators. For example, the inventions would apply equally to most single ended regulators, such as a buck-boost regulators, and regulators having switches referred to a floating or a switching potential such as various types of bridge regulators.
References to the present invention herein are not intended to limit the scope of any claim or claim term, but instead merely make reference to one or more features that may be covered by one or more of the claims. Materials and processes described above are exemplary only, and should not be deemed to limit the claims. | The invention relates to methods for supplying current to an auxiliary power supply for the control circuit of a switching regulator. The auxiliary power supply is connected in parallel to a first switch of the switching regulator. The auxiliary power supply comprises a second switch. During the nonswitching stage of the switching regulator, the second switch has significant impedance so as to power up the auxiliary power supply gradually and to suppress the flow of large or oscillatory currents which may cause damage or create interference. During the switching stage of the switching regulator, the second switch has negligible impedance so as to avoid undue dissipation within the path for the supply of current. | 7 |
RELATED APPLICATIONS
[0001] This application is a divisional of application Ser. No. 11/278,765 filed Apr. 5, 2006, entitled Conduction-Cooled Accelerated Test Fixture.
GOVERNMENT FUNDING
[0002] This invention was made with Government support under contract N00019-02-C-3002 awarded by the Department of the Navy. The Government has certain rights in this invention.
TECHNICAL FIELD OF THE INVENTION
[0003] This invention relates generally to the field of highly-accelerated life testing (HALT) fixtures and, more particularly, to a conduction-cooled accelerated test fixture.
BACKGROUND OF THE INVENTION
[0004] It is important for a manufacturer to test its products before releasing them to the public to ensure that the products function reliably when released. Faulty or dysfunctional products can often cause consumer confidence in the manufacturer to decrease, and in addition, can have costly repercussions for the manufacturer consisting of, among other things, product recalls, product liability suits, and the like. However, thorough testing of consumer products can be realized through the use of HALT fixtures.
[0005] HALT fixtures are designed to test products to uncover design defects and weaknesses in electronic and electro-mechanical assemblies by applying extreme vibrational and thermal stresses to the product. The thermal stresses can consist of rapid and extreme temperature changes. Through the application of such stresses to a product during HALT testing, the HALT fixture can emulate in a brief time frame (i.e., a few days or hours) the entire lifetime of stresses that a product will typically undergo during conventional use.
SUMMARY OF THE INVENTION
[0006] According to one embodiment of the invention, a testing apparatus for executing highly accelerated life testing on at least one test subject includes at least one structure operable to thermally stress the test subject via conduction and at least one pneumatic hammer operable to input imparting vibrations to the test subject. According to another embodiment of the invention, a method for executing highly accelerated life testing of at least one test subject includes applying a thermal stress to the test subject via conduction at a rate of change of at least 8° C. per minute and imparting vibrations to the test subject at a rate of at least 3 Gs rms.
[0007] Certain embodiments of the invention may provide numerous technical advantages. For example, a technical advantage of one embodiment may include the reduction of overlooked design flaws or weaknesses, which reduction results from more accurate emulation of the test subject's thermal environment during HALT testing. An additional technical advantage of this embodiment and/or of an alternate embodiment may include chamber-free HALT testing.
[0008] Although specific advantages have been enumerated above, various embodiments may include all, some, or none of the enumerated advantages. Additionally, other technical advantages may become readily apparent to one of ordinary skill in the art after review of the following figures and description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] For a more complete understanding of example embodiments of the present invention and its advantages, reference is now made to the following description, taken in conjunction with the accompanying drawings, in which:
[0010] FIG. 1 is a schematic diagram of an example embodiment of a testing apparatus housed inside of a chamber;
[0011] FIG. 2 is an illustration of the testing apparatus of FIG. 1 ;
[0012] FIG. 3A is an illustration of the inner face of a rail of the testing apparatus of FIG. 1 ;
[0013] FIG. 3B is an illustration of an alternate view of the inner face of the rail of FIG. 3A ;
[0014] FIG. 3C is a schematic diagram of a vertical cross-section of the short side of the rail of FIG. 3A ; and
[0015] FIG. 3D is a schematic diagram of a vertical cross-section of the long side of the rail of FIG. 3A .
DETAILED DESCRIPTION
[0016] It should be understood at the outset that although example embodiments of the present invention are illustrated below, the present invention may be implemented using any number of techniques, whether currently known or in existence. The present invention should in no way be limited to the example embodiments, drawings, and techniques illustrated below, including the embodiments and implementation illustrated and described herein. Additionally, the drawings are not necessarily drawn to scale.
[0017] FIG. 1 is a schematic diagram of an example embodiment of a testing apparatus 100 housed inside of a chamber 184 . The testing apparatus 100 is operable to stress a test subject 120 by applying either or both of a thermal stress and vibrational stress to the test subject 120 . The test subject 120 can include one or more electrical circuit cards or other electrical components. In one example implementation, the test subject 120 is a circuit card that contains a protective cover; however, test configuration apparatus 100 may be used with a variety of types of test subjects.
[0018] The testing apparatus 100 includes, in this embodiment, a pair of structures 110 for thermally stressing the test subject 120 via conduction heating and/or conduction cooling. In this embodiment, structures 110 are referred to as rails 110 and are illustrated in greater detail in FIGS. 2 through 3D . Conduction heating and/or conduction cooling of the test subject 120 occurs by first heating and/or cooling the rails 110 , which then conduction heat and/or conduction cool the test subject 120 . In one embodiment, the rails 110 abut the edges of test subject 120 , which allows the heating and/or cooling by conduction to take place.
[0019] Conduction cooling may take place, in one embodiment, by first introducing liquid nitrogen (LN 2 ) into a pipe 130 ; however, other cooling fluids may be utilized.
[0020] Previous HALT systems cooled and/or heated a test subject by convection, blowing cold and/or hot air over the test subject. Convection cooling, however, is not effective when testing a high-powered rail-cooled test subject because convection cooling does not accurately simulate the environment that the test subject is exposed to in the field. In particular, certain temperature gradients that the test subject is exposed to in the field cannot be recreated in a test setting by blowing cold and/or hot air over the test subject. In contrast, thermal stress testing of the test subject by conduction cooling and/or conduction heating more accurately simulates the environment that the test subject is exposed to in the field. Additionally, cooling and/or heating by conduction, as opposed to convection, in one embodiment, maintains a dry nitrogen atmosphere around the test subject, thereby eliminating potential electrical shorts due to moisture condensation.
[0021] Referring back to FIG. 1 , the LN 2 flows through the pipe 130 and enters the rails 110 through openings at the bottom of the rails 110 . After entering the rails 110 , the LN 2 flows throughout channels inside of the rails 110 , as is illustrated in, and described in greater detail in conjunction with, FIGS. 3C and 3D . As the LN 2 flows through the internal channels of the rails 110 , the LN 2 evaporates, thereby causing the rails 110 to lose heat. Because the edges of test subject 120 abut the rails 110 , the heat loss experienced by the test subject 120 is transferred to the rails 110 , thereby conduction cooling the test subject 120 . After the LN 2 evaporates, the nitrogen gas exits the rails and vents across the test subject 120 . This process will be further described in connection with FIG. 3A . It is noted that, in one embodiment, neither the LN 2 nor the nitrogen gas comes into contact with the electrical components of the card.
[0022] Conduction cooling the test subject 120 provides a benefit of more accurately emulating the thermal environment of the test subject 120 .
[0023] Conduction heating of the test subject 120 can take place by introducing one or more heated rods 172 into respective openings 112 in the rails 110 , as illustrated in FIG. 2 . The rods 172 may include cartridge heaters, or other types of heaters. Referring back to FIG. 1 , power is provided to the heated rods through a line 140 . When powered, the heated rods heat by conduction the rails 110 . Because the edges of the test subject 120 abut the rails 110 , heat is transferred to the test subject 120 through conduction.
[0024] Additionally, the testing apparatus 100 vibrationally stresses the test subject 120 . Vibrational stress is generated, in one embodiment, by one or more pneumatic hammers 150 that are attached at one end 152 to the bottom of a base plate 180 upon which the rails 110 are fitted. The other end of each pneumatic hammer 150 is left unattached so that it can impart vibrations to the testing apparatus 100 when air is supplied to the pneumatic hammers 150 . The air that drives the pneumatic hammers 150 may be supplied to the testing apparatus 100 via pipe 170 . The testing apparatus 100 is fitted with shock mounts 160 between the base plate 180 and the base 182 of the testing apparatus 100 for dampening the vibrations generated by the pneumatic hammers 150 , in one embodiment.
[0025] In one embodiment of the invention, the testing apparatus 100 is housed inside of a chamber 184 . Chamber 184 includes walls 186 that act as sound proofing, dampening the sound generated by the testing apparatus 100 . Although one embodiment of the testing apparatus 100 utilizes a chamber 184 as a housing, the testing apparatus 100 can be operated without such a chamber 184 , as can be seen in FIG. 2 .
[0026] A computer 190 controls the test settings of the testing apparatus 100 . Computer 190 controls the test settings of the testing apparatus 100 by transmitting signals through a line 191 to an environment controller 192 . Environment controller 192 , in turn, controls the heating, shaking, as well as cooling of the test subject 120 via control lines 194 , 196 , and 198 respectively. Computer 190 may also receive test results from the testing apparatus 100 while thermal and vibrational stresses are applied to the test subject 120 . Additional details of test configuration apparatus 100 are described in conjunction with FIGS. 2 through 3D .
[0027] FIG. 2 is an illustration of selected portions of test configuration apparatus 100 . The frame of the configuration apparatus 100 includes structural support 183 and the base plate 180 . In this embodiment, the test subject 120 includes a plurality of circuit cards. The circuit cards are held in place by card guides 122 , which can be seen more clearly in FIG. 3A . The card guides 122 are also the location where the rails 110 abut the test subject 120 and thus are the location where conduction heating and/or conduction cooling of the test subject 120 takes place.
[0028] With respect to conduction cooling, the LN 2 is piped into the rails 110 through openings on the bottom of the rails 110 . This will be illustrated more clearly in FIG. 3D . Once the LN 2 enters the rails 110 , it flows through various circular channels emptying into central channels, which extend the entire height of the rails 110 , in this embodiment. This will be illustrated more clearly in FIG. 3C . Openings 102 of the central channels are illustrated in FIG. 2 as the center openings in the top surface of the rails 110 , which openings 102 are flanked on two sides by three openings 112 for receiving the heated rods. From the central channels, the LN 2 flows into the cooling tubes, the openings 114 of which can be seen in FIG. 2 . The cooling tubes extend the full length of the rails 110 and will be illustrated more clearly in FIG. 3A . The cooling tubes are the location where the LN 2 evaporates, thus conduction cooling the rails 110 and the card guides 122 which conduction cool the test subject 120 . Variable-sized plugs can be inserted into the openings 114 of the cooling tubes, providing a means for adjusting the amount of cooling of the test subject 120 . In one embodiment, because each opening 114 is associated with a specific card guide 122 , the temperature of each circuit card can be controlled independently from the others.
[0029] FIG. 3A is an illustration of the inner face of the rail 110 of the test configuration apparatus. The rail 110 consists of the card guides 122 into which the test subject is inserted. As mentioned in FIG. 2 , the card guides 122 are conduction cooled by evaporation of the LN 2 in the cooling tubes 113 within columns 115 . Variable-sized plugs can be inserted into the openings 114 of the cooling tubes 113 in order to control the amount of cooling of the test subject. Notches 124 in the rail 110 are openings from which the nitrogen gas vents after cooling the rail 110 and the card guides 122 . With respect to conduction heating, the heated rods mentioned in connection with FIG. 1 can be inserted into the openings 112 to the heating tubes in the rail 110 .
[0030] FIG. 3B is an illustration of an alternate view of the inner face of the rail 110 of the test configuration apparatus.
[0031] The conduction cooling of the rails will be described in more detail in FIGS. 3C and 3D . FIG. 3C is a schematic diagram of a vertical cross-section of the short side of the rail 110 .
[0032] FIG. 3D is a schematic diagram of a vertical cross-section of the long side of the rail 110 . When thermally stressing the test subject by conduction cooling, LN 2 enters the rail 110 through slot 108 . The LN 2 is then circulated through the rail 110 via the circular channels 104 until it reaches the opening 106 to the central channel 103 . The LN 2 flows into the central channel 103 , which then distributes the LN 2 to each of the vertical cooling tubes 113 . As the LN 2 flows through the various channels, it evaporates, conduction cooling the rail 110 and card guides 122 , which conduction cools the test subject.
[0033] The teachings of the invention described hereinabove are applicable to testing purposes other than HALT, such as Highly Accelerated Stress Screening (HASS).
[0034] Numerous other changes, substitutions, variations, alterations and modifications may be ascertained by those skilled in the art and it is intended that the present invention encompass all such changes, substitutions, variations, alterations and modifications as falling within the spirit and scope of the appended claims. | According to one embodiment of the invention, a testing apparatus for executing highly accelerated life testing on at least one test subject includes at least one structure operable to thermally stress the test subject via conduction and at least one pneumatic hammer operable to input imparting vibrations to the test subject. According to another embodiment of the invention, a method for executing highly accelerated life testing of at least one test subject includes applying a thermal stress to the test subject via conduction at a rate of change of at least 8° C. per minute and imparting vibrations to the test subject at a rate of at least 3 Gs rms. | 6 |
This is a division of application Ser. No. 07/616,214, filed Nov. 20, 1990.
BACKGROUND
1. Field of the Invention
This invention is directed to solenoids, in general, and to an improved solenoid which is adaptable to operate the valves in most irrigation systems by means of a versatile, yet simple, adjustment to the novel plunger thereof, in particular.
2. Prior Art
A wide variety of irrigation systems and other fluid control systems are known. These systems usually contain valves which are opened and closed by means of a solenoid, thereby controlling the flow or non-flow of water or other fluids. The valves of the existing systems have fluid constantly being delivered by pipes or other usual means. The solenoid controlled valve is positioned at a desired place in the fluid flow pattern such that it is able to stop or permit the fluid flow selectively. Typically, the solenoid includes a coil and a plunger which is controlled by signals supplied to the coil. The signals are supplied, by a control panel which is usually remote from the solenoid. Normally, a signal is supplied to the solenoid to move the plunger relative to the coil. Movement of the plunger operates to control the valve in the irrigation system. When the coil within the solenoid is activated, the plunger, typically, is pulled into the solenoid toward the coil by the electromagnetic force produced at the coil. Typically, this operation moves the plunger off the solenoid discharge port within the valve, thereby permitting the water pressure to force the valve open. When the signal to the coil ceases, the plunger is pushed by a spring to a position extended from the solenoid. In this extended position, the plunger blocks the fluid flow by moving onto the solenoid discharge port, i.e., the valve is closed. Of course, whenever a solenoid ceases to function properly, the valve may be "frozen" shut and no fluid is delivered to the system. Conversely, the valve may remain in the open (or partially open) condition and constantly leak fluid. Neither of these arrangements is satisfactory and, usually, the only solution currently available is to replace the entire valve or, at least the entire solenoid in the valve.
When an irrigation system uses only one model of valve or solenoid, the replacement of a solenoid can be a relatively simple task, assuming the part is still available from the manufacturer. In more complex irrigation systems which have been installed over time and/or under the direction of several individuals, there is likely to be more than one type of equipment present. In both of these situations, replacing a solenoid can become a futile act of trying to find the matching manufacturer replacement. Some solenoids are difficult to obtain. Other solenoids are impossible to obtain because they are no longer manufactured Those persons in charge of irrigation systems may, therefore, find it necessary to keep a large and varied inventory of solenoids on hand to be able to promptly replace those which fail before the flora is damaged, the location is flooded, or the like.
Maintaining such an inventory of solenoids is not only costly, but requires much storage space and complex record keeping to maintain an adequate supply. Moreover, the inventory is, eventually, depleted and the problem of obtaining proper solenoids recurs.
One of the most irksome and expensive parts of the replacement process is the frustrating attempt to replace a solenoid even when large inventories are available. Typically, the irrigation specialist takes a dozen of the most likely types of solenoids into the field for repair and/or replacement. This inefficient operation can be even more exasperating if the specialist finds that none of the units is appropriate. Now a return trip must be made to obtain the correct model of solenoid, assuming that it is even available. Then another service trip is made into the field to finally do the actual replacement work. Thus, the replacement process becomes even more expensive and time consuming.
The difficulty of the replacement process was somewhat reduced by the introduction of a solenoid which has three different height replacement plungers. This multiple-plunger solenoid is sold under the trademark SUPER MAX. (SUPER MAX is a trademark of National Irrigation Specialists of Anaheim, Calif.). In this solenoid, a plurality of interchangeable plungers of different lengths is provided. To implement this system, a chart is provided with the SUPER MAX solenoid which keys each of the different plungers to specific irrigation systems.
While this solenoid was a vast improvement over the huge inventory method of solenoid preparedness, it is still cumbersome, requiring a chart and extensive parts inventory. For example, in any replacement at least two of the three plungers will be unnecessary.
In addition, the SUPER MAX solenoid is made to cover a broad spectrum of valves with only three fixed dimension plungers. The valve models produced by the different manufacturers vary slightly. In addition, the variations between different brands of irrigation systems frequently results in a less than perfect fit of these "general-fit" plungers. The nature of each plunger is to cover more than one type of valve and, therefore, is like the proverbial "Jack of all trades and master of none". The fit of the plunger is frequently good, but not perfect in many situations. For example, if the plunger is too short, the magnetic field within the body of the solenoid is unable to "capture" the plunger, pull it up and thereby open the valve. Conversely, if the plunger is too long, the valve is always closed because there is no space in which it may move toward the magnetic field and thereby open the valve.
Although solenoids of irrigation systems are discussed above, any fluid control system which includes the use of valves and electrically activated solenoids has comparable difficulties. There is clearly a need for a precisely fitted solenoid which will serve as a replacement in any irrigation or fluid control system. Such a solenoid will provide the additional benefits of reduced inventory and associated costs, lower labor costs because repeat trips to the field are unnecessary, and elimination of the problem of unavailable solenoid models.
PRIOR ART STATEMENT
No formal prior art search has been made but reference to the SUPER MAX device is noted supra.
SUMMARY OF THE INSTANT INVENTION
The instant invention is directed to a solenoid which is versatile and useful. The solenoid includes an activating coil and a plunger moveably mounted within the activating coil. The plunger can be adjusted to virtually any height thereby making the solenoid of the instant invention adaptable to valves within virtually all irrigation systems.
The threaded base of the solenoid permits the solenoid to be mounted at the valve. The threaded base is elongated to accomodate the plunger of the invention. The threaded base of the solenoid may have multiple pitch threads which enables the solenoid to be used with a variety of valves having different threads.
The solenoid includes a bleed screw which allows the water pressure on the discharge port of the valve to be reduced, thereby permitting the valve to open. The bleed screw of the invention is uniquely constructed to minimally disrupt the electromagnetic field created by the actuating coil yet effectively relieving the water pressure.
The preferred embodiment of the invention includes a two piece plunger. The two piece plunger includes a main body which fits within the solenoid coil in a conventional manner. The main body includes an axial bore therein which is threaded on the inner surface thereof. The main body is as long as possible to insure that there is sufficient ferrous material present for the electromagnetic field created to be able to capture the plunger. A second body is adapted to engage the threaded surface of the axial bore of the main body. Thus, the overall length of the plunger can be adjusted by the screw action of the threaded members.
In one embodiment of the invention, the adjustable plunger has a nylon strip inserted in a slot in the threaded tail of the second body. The strip stabilizes and substantially locks the plunger parts in place thereby maintaining a fixed position and plunger length.
The instant invention also includes a measurement standard composed of a hollow tube with a flat-headed piston snugly, but slideably, fitted therein. Thus, the piston slides within the tube but tends to remain in a fixed position relative to the tube. The thickness of the flat head of the piston is precisely equal to the length of travel necessary to permit opening and closing the valve by movement of the plunger within the solenoid. This measurement standard is used to determine the proper height of the adjustable plunger to be used by the replacement solenoid.
In operation, the measurement standard is fully extended and placed into the plunger aperture axially disposed within the solenoid body. The solenoid is then fully assembled and positioned onto the valve. When the solenoid is positioned on the valve, the piston of the measurement standard is compressed into the tube so that the standard assumes the exact height of the plunger space. The solenoid is removed from the valve and the measurement standard removed from the solenoid.
The measurement standard and the adjustable plunger are compared. The plunger is manipulated until the top of the head is flush with the base of the flat head of the piston of the standard. The properly sized plunger is placed within the solenoid body which is now assembled and positioned on the valve.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded view of the solenoid.
FIG. 2 is a partially cut-away, partially cross-sectional view of the solenoid with the adjusted plunger in the core.
FIG. 3 is a side view of the measurement standard beside a properly adjusted plunger.
FIG. 4 is a partially cut-away, partially cross-sectional view of the solenoid of another embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIGS. 1 and 2 concurrently, there is shown one embodiment of the instant invention. The solenoid 100 includes a main body 150 and a movable armature or plunger 112 associated therewith. In the preferred embodiment, the main body 150 includes a support core 147. The core 147 includes an axial aperture 128 which is shaped to slideably accomodate armature 112. In the embodiment shown, both the plunger 112 and aperture 128 are cylindrically shaped, although other shapes such as hexagonal, rectangular, and the like can be utilized. A bleed screw 136 is provided at the other end of the support core 147.
In the embodiment shown, the actuating coil 132 formed on bobbin 101 or similar support and is removeably mounted on the core 147. However, coil 132 may be an integral part of main body 150 of the solenoid as is commonly known in the art. An external housing 149 can be used to enclose the coil 132. The coil 132 can be potted within the housing 149 (or on bobbin 101) in a conventional manner. Electrical wires 138 are used to connect actuating coil 132 to an external power source. When power is supplied to the coil 132 through wires 138, an electromagnetic field is created at core 147 which is operative to capture and move plunger 112 within aperture 128.
An enlarged base 134 is provided at one end of core 147. The base 134 includes shoulder 139 which supports coil 132. The base 134 includes an externally threaded base portion 144. In the embodiment shown, the base 134 includes apertures 142 for receiving solenoid removal tools. Of course, apertures 142 may have any suitable shape, such as oval, hexagonal, or the like The apertures 142 may even be omitted.
In a preferred embodiment, threaded base portion 144 includes multiple pitch threads. This enables the threaded base portion 144 to engage a variety of connectors or valves which may have different thread pitches. Of course, a base with a single thread pitch may be used. In addition, as shown in FIG. 2, an adapter 115 can be utilized. The adapter 115 is an annular ring which is threaded on the inner and outer surfaces The inner surface threads are adapted to engage the threads on the threaded base portion 144. The outer threads of adapter 115 are adapted to engage the threads on a valve. The adapter permits the solenoid to be used with valves having different size openings.
In addition, an O-ring 116 is mounted at the exterior of the threaded base portion 134 adjacent to the shoulder 139. The O-ring 116 can be used to provide a suitable seal for the solenoid whether the adapter 115 is utilized or not. That is the O-ring 116 can be sealed against the upper edge of the valve, per se, or the upper edge of the adapter 115 if so utilized.
In addition, an O-ring 133 can be mounted at the outer edge of the threaded base portion 144 (or at the inner surface of adapter 115) in order to provide a suitable seal between the core 147 and the adapter 115. This O-ring 133 provides another measure of sealing for the apparatus, especially when the adapter 115 is utilized.
The opposite end of the core 147 is also threaded to receive a bleed screw 136 for permitting spurious water to be vented from the solenoid. In the embodiment shown in FIGS. 1 and 2 the upper end of aperture 128 is internally threaded. The upper end of aperture 128 can be of smaller diameter than the lower end. A baffle 140 includes a small diameter aperture 160 axially therethrough. The baffle 140 is disposed intermediate the ends of core 147 and separates the upper and lower portions of aperture 12. The baffle provides a seat for the plunger 112. The aperture 160 permits extraneous fluids to be removed from the core 147 via the aperture in bleed screw 136. The manual bleed screw 136 is adapted to threadably engage the internally threaded portion of aperature 128 in core 147. O-ring 162 provides a tight seal between bleed screw 136 and core 147. The bleed screw 136 includes an internal aperture 126. The aperture 126 of bleed screw 136 has an inverted L-shape which extends axially along the screw and out of the stem thereof. The aperture 126 is closed when bleed screw 136 is inserted into the core 147. When aperture 126 is closed (i.e., bleed screw 136 is fully inserted into core 147), water pressure is maintained so that the plunger 112 is positioned to open or close the valve in response to electrical signals sent through Wires 138 to coil 132.
Conversely, when bleed screw 136 is partially disengaged from core 147, water pressure is manually relieved so that the plunger 112 moves into aperture 128 and the valve is opened or spurious water in the solenoid is removed.
The plunger 112 is composed of a core 114 with a central, axial bore 125 therein. The bore can pass through the core 112. Typically, the bore 125 is threaded on the inner surface thereof. An adjustable head 118 includes a threaded portion thereof which is adjustably mounted within the bore of core 114.
In this embodiment, the head 118 is fabricated of a steel alloy threaded rod or "screw". However, the head 118 can also be plastic or the like. In a preferred construction, a nylon strip 122 is adhered along one side of the threaded portion of head 118. Typically, the nylon strip 122 is mounted in an aperture of appropriate size and shape at the surface of screw 118. In the preferred embodiment, the nylon strip extends along a substantial portion of the length of the screw 118. This arrangement permits a greater area of control and length of screw adjustment. Alternatively, a pellet or dot or a series of pellets or dots of nylon can be used. The nylon strip is nearly flush with the peak of the threads of screw 118 so as to make a suitable binding fit with core 114. Such fasteners are fabricated by Buckley QC Fasteners.
While the threads of the screw 118 alone are considered adequate to stabilize the screw within the plunger, the nylon strip 122 provides an additional means to secure the screw 118 once it has been adjusted Other suitable methods m be used to provide additional assurance that the position of the screw 118 will be maintained. For example, head 118 can be formed of plastic wherein the threads could be purposely distorted so as to provide the desired binding.
The head 118 is turned to adjust the height thereof relative to the core 114. Moreover, head 118 may be covered by rubber-like material to provide some flexibility as the plunger 112 moves within the solenoid body 150 and to provide a rubber seat to seal against the valve discharge port. When the head 118 of the plunger 112 is pushed against the valve discharge port (not shown), the valve is closed. Other material which has sufficient cushioning ability and durability may be used.
The core 114 of the plunger 112 is composed of alloy steel in this embodiment. However, other materials are contemplated which also contain sufficient ferrous matter to permit the plunger 112 to be electromagnetically attracted or "captured" by the magnetic field created by the coil within the solenoid body 150. The plunger core 114 can have an inner ferrous layer while the exterior is comprised of any durable and even non-ferrous material.
Although an alloy steel, screw-type head 118 is shown in this embodiment, other adjustable fasteners of suitable materials are contemplated. Likewise, fasteners such as notched pins, and the like may be utilized.
The configuration of the core 114 and spring 116 are such as to have the spring 116 positioned at one end of the core 114. Any number of methods and configurations would make this possible. In this embodiment, a slight depression or groove 107 is formed adjacent one end of the core 114. The groove 107 in the outer surface of core 114 produces a recess or neck for retaining the spring 116. A reduced diameter or tightened coiling of one or more turns of the spring 116 is used to hold the spring 116 in place in groove 107 on the core 114.
When the plunger 112 is inserted into the aperture 128 in the solenoid body 150, the larger end of spring 116 rests upon the inner shoulder 130 within the aperture 128. The spring 116 may prevent the base of the plunger 112 from contacting the bottom of the aperture 128 (i.e., baffle 140) when the plunger 112 is in its extended state. When the separation between the plunger 112 and the bottom of aperture 128 is maintained, the valve is closed.
Conversely, when coil 132 is activated by an electrical signal, an electromagnetic force is created which draws plunger 112 into aperture 128. As the plunger 112 moves inwardly, the spring 116 is compressed between the shoulder 130 and the upper end of core 114. This inward shift of the plunger 112, moves the head 118 off of the valve discharge port whereby the valve is forced open.
Although a coiled spring 116 is used in this embodiment to position the plunger 112 within the solenoid body, other flexible, expandable and/or compressible means which allow the movement of the plunger 112 are contemplated. The coiled spring 116 in this embodiment is composed of steel, but other resilient materials are contemplated.
Referring now to FIG. 3, plunger 112 and the measurement standard 200 of the instant invention are shown in side-by-side relation. The measurement standard 200 is composed of a tube 234 with a blind bore 280 therein. A piston 232 which is insertable into the bore 280 in the tube 234 includes a flathead 236. Both the tube and the piston may be manufactured of some plastic material such as delrin, nylon, ABS or the like.
The piston 232 is snugly slideable in the bore 280 within the tube 234. The thickness T of the flat head 236 is selected to be equal to the length of travel necessary for plunger 112 within the core 147 to allow the solenoid 100 to function in opening and closing the valve.
In order to determine the exact length of the adjustable plunger 112 for the solenoid under repair, the standard 200 is utilized. The piston 232 is extended as far as possible outwardly from the tube 234. The fully extended measurement standard 200 is positioned within the aperture 128 in the solenoid 100. The solenoid is assembled and positioned on the valve. As this is done, the piston 232 is compressed into the bore 280 in tube 234. The standard 200 now corresponds to the length of the interior space in core 147 when positioned on the valve.
The solenoid is removed from the valve and the measurement standard 200, maintaining the compressed length, is removed from the solenoid. The compressed measurement standard 200 is placed on a level surface next to the adjustable plunger 112. To achieve the proper height for the plunger 112 in this particular valve, the plunger 112 is adjusted so that the top surface of the head 118 is flush with the bottom surface of the flat head 236 of the piston 232, as shown in FIG. 3. The properly adjusted plunger 112 is now inserted into aperture 128 of the solenoid body 150 and assembled. The solenoid is then positioned onto the valve.
By this apparatus and procedure, the solenoid is an exact replacement for the valve of virtually any irrigation system. A similar apparatus and procedure is used for other fluid control systems which utilize a valve, solenoid, and an activation means to regulate the flow of the fluid.
Referring now to FIG. 4, there is shown a partially broken away and partially cross-sectional view of another embodiment of the instant invention. In this embodiment, similar components bear similar reference numerals.
The solenoid 400 shown in FIG. 4 includes a core 447 which is, generally, similar to the core 147 shown in FIGS. 1 and 2. In solenoid 400, the same coil and cannister arrangements can be utilized as in solenoid 100. However, as shown in FIG. 4, the coil 432 (including connecting wires 138) is a self-contained unit which can be an epoxy resin filled unit, with or without a cannister. This unit is or can be mounted directly onto the core 447. Of course, the coil can be removably mounted, if so desired. The core 447 includes the threaded base portion 434 as shown in FIGS. 1 and 2. Likewise, an adapter 415 is provided. The O-ring 116 is provided against the shoulder 139 and the O-ring 133 is provided between the base 434 and the adapter 415 in the same fashion as described above relative to the embodiment of FIG. 2. A plunger 412 with the appropriate coil spring 406 and the like is also provided. The plunger 412 comprises a head 118 which is adjustably mounted to base 114 in the same fashion shown and described above. The core 447 includes a first shoulder and the inner bore 428 into which the plunger 412 is mounted.
In this embodiment, the core 447 comprises a relatively small diameter axial bore 460 through the upper end thereof. That is, the upper end of the core 447 is a relatively solid piece contrary to the hollow core shown in FIG. 2. The outer surface of core 447 has a threaded portion 448 at the outer extension thereof and is adapted to receive a cap 436 which has a threaded inner surface. A washer 451 is mounted over the end of core 447 and secured in place by the cap 436. A gasket 449 is provided between the end of core 447 and the inner top surface of cap 436. The gasket 449 provides a seal between the cap and the core.
The aperture 464 passes through the side wall of cap 436. In order to bleed the solenoid, cap 436 is loosened sufficiently so that the cap is displaced from the end of core 447 thereby producing an open space between the core and the inner surface of the cap. When the aperture 464 n cap 436 communicates with the space between the cap and the core, any fluid in the core is able to bleed off.
As noted, the coil 432 is maintained in place by cap 436 in conjunction with washer 451. The holding washer 451 may be a flat type as shown, but other suitable types are possible such as wavy or spring washers, among others. If it is necessary to replace the coil 432, the bleed cap 436 is removed along with the washer 451. The coil 432 is then removed from the core 447, a new one replaced, and the washer 451 and cap 436 are replaced. This embodiment has the advantage of relatively lower cost of fabrication as well as a somewhat smaller size which is obtainable because of the omission of the cannister to secure the coil in the solenoid.
Thus, there is shown and described a preferred embodiment of the instant invention. Those skilled in the art may conceive of modifications or variations to the described embodiment Any such modifications or variations which fall within the purview of this description are intended to be illustrative only and are not intended to be limitative. Rather, the scope of the invention is limited only by the claims appended hereto. | A solenoid valve comprising with a plunger which is readily and accurately adjustable to various heights whereby the solenoid is able to function with virtually all fluid flow control systems. The solenoid includes an elongated base which may have multiple threads to accommodate a variety of connectors and a bleed screw formed to be minimally disruptive to the electromagnetic field. A measurement standard, in the form of a cylinder and piston combination, is shaped to fit within the solenoid body and accurately determine the desired length of the specific plunger. The piston is mounted to move in the cylinder and, in conjunction with the cylinder, to assume the exact length required for the plunger within the solenoid to function correctly in operating the valve. The plunger is adjustable which allows the height thereof to be precisely and securely set to the height determined by the measurement standard. | 7 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The present application claims the benefit of Chinese Application Serial No. 224662, filed Sep. 28, 2009, entitled FLOW RATE SWITCHING DEVICE DESIGNED FOR SHOWERS, and Chinese Application Serial No. 224663, filed Sep. 28, 2009, entitled FLOW RATE SWITCHING DEVICE DESIGNED FOR SHOWERS, the disclosures of which are hereby incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to water-saving products, and more particularly to water-saving shower head devices. Still more particularly, the present invention relates to shower heads capable of various flow rates.
BACKGROUND OF THE INVENTION
[0003] As natural resources continue to dwindle, and particularly water resources, the public has become more conscious of the need for energy savings as well as environmental protection. For this reason and others, water-saving products of various kinds have now been widely accepted. For example, water-saving bubblers are frequently used in people's daily lives, but the current state of the art can only realize water savings by limiting flow rates, and the shower heads known in the art are incapable of switching flow rates while at the same time maintaining stable flow rates with changing water pressure so that the ability to save water is neither stable nor significant.
[0004] For example, U.S. Pat. No. 6,126,091 discloses a shower head with both a pulsation and variable flow rate in which a plurality of orifices within the housing creates different water streams by means of a rotary valve within the housing to produce pulsating water streams. Furthermore, U.S. Pat. No. 6,223,998 discloses a shower head and a valve member and mechanism for selectively directing the flow of water directly to nozzle orifices or to drive jets for a water pulsating turbine wheel. However, the search for improved devices has continued unabated.
BRIEF SUMMARY OF THE INVENTION
[0005] In accordance with the present invention, these and other objects have now been realized by the discovery of apparatus comprising a shower head including a body for directing a flow of water, an outlet member associated with the body, the outlet member having a plurality of outlet channels corresponding to a plurality of flow rates for the flow of water, the outlet member including a rotating member for switching the flow of water through a selected one of the plurality of outlet channels, and a corresponding plurality of pressure compensators disposed in the plurality of outlet channels for stabilizing the flow of water at the plurality of flow rates. In a preferred embodiment of the apparatus of the present invention, the apparatus includes a diverter affixed for rotation with the rotating member, the diverter including a plurality of outlet orifices corresponding to the plurality of outlet channels, whereby upon rotation of the rotating member, the diverter directs the flow of water through one of the plurality of outlet orifices. In a preferred embodiment, the apparatus includes a floating cap affixed to the body, the floating cap including an inlet orifice for directing the flow of water through the floating cap and into one of the plurality of outlet orifices in the diverter. In a more preferred embodiment, the floating cap includes a upper surface and a lower surface, the lower surface being proximate to the diverter and including a plurality of slots corresponding to the plurality of outlet channels, and the diverter includes an upper portion proximate to the floating cap and a lower portion, and including a pin member urgingly projecting from the upper surface of the diverter for selected insertion into a selected one of the plurality of slots in the floating cap. In a highly preferred embodiment, the apparatus includes a spring member for urging the pin member from the upper surface of the diverter into the selected one of the plurality of slots in the floating cap.
[0006] In accordance with one embodiment of the apparatus of the present invention, the body includes a plurality of body portions including an intermediate body portion rotatably affixed to the body, and wherein the rotating member is affixed to the intermediate body portion for rotation therewith. In a preferred embodiment, the plurality of body portions includes an upper body portion and a lower body portion surrounding the intermediate body portion. In another embodiment, the apparatus includes a ball joint rotatably affixed to the upper body portion.
[0007] In accordance with another embodiment of the apparatus of the present invention, the lower body portion is affixed to the intermediate body portion for rotation therewith.
[0008] In accordance with another embodiment of the apparatus of the present invention, the apparatus includes a rotatable sheath connected to both the intermediate body portion and the lower portion for rotation therewith. In a preferred embodiment, the apparatus includes a bracket member connected to the upper body portion and surrounding at least a portion of the rotatable sheath.
[0009] In accordance with another embodiment of the apparatus of the present invention, the apparatus includes a water body for directing the water outwardly from the apparatus and a water conducting body, the water conducting body means opposed between the diverter and the water body and each of the water body, the water conducting body, and the diverter being attached to the rotatable sheath.
[0010] In accordance with another embodiment of the apparatus of the present invention, the plurality of outlet orifices in the diverter includes three outlet orifices. In a preferred embodiment, two of the plurality of pressure compensators are located in two of the three orifices.
[0011] In a most preferred embodiment, the apparatus includes a ball joint rotatably affixed to the body, and the third pressure compensator is associated with the ball joint.
[0012] In accordance with the present invention, a flow switching device is provided for showers in order to ensure that different flow rates can be used, but that when water pressure changes occur within a predetermined range each of these flow rates remains stable so that effective and stabilized water savings can be realized.
BRIEF DESCRIPTION OF TEE DRAWINGS
[0013] The present invention may be more fully appreciated with reference to the following detailed description, which in turn refers to the Figures, in which:
[0014] FIG. 1 is a side, elevational, schematic, sectional view of an apparatus in accordance with the present invention;
[0015] FIG. 2 is a side, elevational view of the apparatus shown in FIG. 1 ;
[0016] FIG. 3 is a top, perspective view of the apparatus shown in FIG. 1 ;
[0017] FIG. 4 is a top, elevational view of the apparatus shown in FIG. 1 ;
[0018] FIG. 5 is a bottom, elevational view of the apparatus shown in FIG. 1 ;
[0019] FIG. 6 is a side, perspective, exploded view of the apparatus shown in FIG. 1 ;
[0020] FIG. 7 is a side, elevational, exploded view of the apparatus shown in FIG. 6 in reverse order; and
[0021] FIG. 8 is a top, elevational view of a diverter used in the apparatus of the present invention.
DETAILED DESCRIPTION
[0022] A preferred embodiment of the apparatus of the present invention is shown in the form of the shower head assembly as shown in FIG. 1 . As will be discussed in more detail below, this device allows for the use of multiple flow rate outlet orifices with multiple corresponding pressure compensators so that the user can switch to different outlet orifices corresponding to different flow rates, and at the same time these flow rates can be properly controlled by the pressure compensators hereof. Thus, in a preferred embodiment there are three channels which the flow of water can follow, preferably comprising flow rates of 1.5 gallons per minute, 1.0 gallons per minutes, and 0.5 gallons per minutes, each of which has a unique pressure compensator designed to coincide with the particular flow rate therein.
[0023] Turning to FIG. 1 , which can be seen in an exploded format in FIGS. 6 and 7 , the shower head 1 comprises a body 1 a which specifically includes an upper body portion 5 , an intermediate body portion 21 , and a lower body portion 22 . The upper body portion 5 includes an opening 5 a which contains a ball joint 2 fully rotatable within the upper body portion 5 . The upper portion of ball joint 2 includes a threadable portion 2 a threadable to a water pipe fixture or the like, and a sealing washer 2 b . The intermediate body portion 21 is affixed to the lower body portion 22 by means of fasteners or the like, but more preferably by means of a locking feature. Thus, a series of tabs 22 a with upper flanges 22 b are inserted into corresponding slots 21 a in intermediate body portion 21 . This creates a one-way snap-in feature for connecting the lower and intermediate body portions permanently together. Furthermore, the combination of intermediate body portion 21 and lower body portion 22 will be rotatable with respect to the upper body portion 5 , as will be discussed in more detail below.
[0024] A bracket 15 is installed within the body, affixed to upper body portion 5 by means of bolts such as bolts or screws 15 a or the like. Within the bracket 15 , and between ball joint 2 and upper body portion 5 , is disposed a sealing ring 6 for purposes of sealing the ball joint with respect to the body. The bracket 15 thus extends down to or below the level of upper body portion 5 , as shown in FIG. 1 . A rotatable sheath 20 is then disposed within the lower depending portion of bracket 15 , and is affixed to the intermediate body portion 21 as well as to lower body portion 22 by means of various fasteners or the like. In this manner, the rotatable sheath 20 is maintained within the body, such as by the interaction of outwardly extending flange portion 20 a of the rotatable sheath and an inwardly extending flange portion 15 b extending inwardly to interact with the flange portion 20 a and prevent the rotatable sheath 20 from leaving the body itself. In addition, sealing ring 14 is installed between the rotatable sheath 20 and the bracket 15 within an indented area of the rotatable sheath 20 .
[0025] Returning to the upper portion of the apparatus, the interior portion of the ball joint 2 includes an open area 2 c for the flow of water as it exits the connected pipe or tap (not shown). Within area 2 c is mounted affixing bracket 4 holding a first pressure compensator 3 which in this embodiment is the maximum size pressure compensator for the maximum flow within the apparatus itself, such as 1.5 gpm. The pressure compensator 3 itself includes a number of spaced-apart water inlet openings for the flow of water therethrough.
[0026] Above the rotatable sheath 20 and below the ball joint 5 is initially mounted a floating cap 11 . Between the floating cap 11 and the rotatable bracket 15 a seal 9 is provided. The floating cap 11 is maintained in position relative to the bracket 15 by means of a pressure spring 10 which urges the floating cap 11 downwardly from the ball joint 2 . In this manner, the outwardly extending flange 11 a of the floating cap 11 is pressed against inwardly extending flange 15 c of the bracket 15 in order to do so. Below the floating cap 11 is mounted the diverter 12 which can be specifically seen, for example, in FIG. 8 hereof. The diverter 12 is in contact with the inner surface of the rotatable sheath 20 . The lower surface of the floating cap 11 includes positioning slots 111 at predetermined locations thereabout. The upper surface of the diverter 12 includes a projecting pin 7 which is urged upwardly by a positioning spring 8 therewithin. Thus, upon rotation of the diverter 12 along with rotation of the entire intermediate and lower body portions 21 and 22 , and thus the rotatable sheath 20 , the positioning pin 8 can enter into any one of the positioning slots 111 in the lower surface of the floating ring 11 . Each of these positions corresponds to one of the positions, which in a preferred embodiment includes three positions, in which the flow of water through one of the outlet orifices in the diverter 12 can take place. Thus, each corresponds with a different one of the outlet orifices 12 a , 12 b or 12 c in the diverter 12 . (See FIG. 8 .) In a preferred embodiment as shown in FIG. 1 , the outlet orifice 12 a corresponds to the maximum flow rate, preferably 1.5 g/m. The flow directed through the opening 2 c in the ball joint thus passes through the maximum flow pressure compensator 3 therein before entering orifice 12 a.
[0027] Upon rotation of the diverter 12 into its second position, where the flow of water from the ball joint 2 enters orifice 12 b , this corresponds to the intermediate flow rate of 1.0 g/m, and in this case a second pressure flow compensator 13 is maintained directly within the orifice 12 b so that the water will flow directly therethrough,; i.e., after it has also passed through the first pressure flow compensator 3 . Finally, in the third position of diverter 12 the orifice opening 12 c is in alignment with the flow of water from the ball joint 2 , this orifice corresponding to the minimum flow rate of 0.5 g/m. Once again in this case, another pressure compensator 13 ′ is located within the orifice 12 c for control of the flow therethrough.
[0028] Below the diverter 12 is mounted a water conducting body 17 for receiving the flow through one of the three outlet orifices in the diverter 12 , namely orifice 12 a , 12 b or 12 c , and directing it downwardly. Once again, a sealing ring 18 is installed between the water conducting body 17 and the rotatable sheath 20 . Mounted below the water conducting body 17 is water body 19 . Water body 19 includes an upper flange portion 19 a extending outwardly and interacting with an inwardly extending flange portion 20 b extending from the rotatable sheath 20 for maintaining the water body 19 in its desired position therein. The water itself will exit from water body 19 and thus from the entire shower head assembly itself.
[0029] The maximum pressure compensator 3 thus ensures that, even with switching of the various flow rates the stability of the flow rate, that is the maximum flow rate itself, will never exceed the rated flow rate for this device. The additional pressure compensators 13 and 13 ′ ensure the stability of the flow rates through orifices 12 b and 12 c , namely the intermediate and minimum flow rates. The pressure compensators themselves are the subject of co-pending International Application No. PCT/US2010/41551, filed on Jul. 9, 2010, the disclosure of which is incorporated herein by reference thereto. In general, these pressure compensators are flexible or rubber-like bodies which include orifices or other paths for the flow of water therethrough. These pressure compensators thus compensate for changes in the water pressure by flexing to thereby alter the size of these water channels and maintain the flow rates during said pressure changes.
[0030] In operational use of this device, the user will rotate the intermediate and lower body portions, 21 and 22 , which thus rotates the rotatable sheath 20 along therewith. Thus, the pin 7 and positioning spring 8 cause the pin 7 to enter one of the positioning slots 111 on the lower body of the floating cap 11 corresponding with one of the outlet orifice 12 a , 12 b or 12 c . Thus, whatever one of the various flow rates, three in this case, is in alignment with the water flow, at least one pressure compensator will ensure that during shifts in the water pressure the flow rate through the outlet orifices remains stabilized, thus achieving stable and water-saving effects thereby. It is, of course, clear that the present invention is not limited to a particular number such as three outlet orifices, but could include more or less outlet orifices depending on the number of different water flow rates which are desired for use therein.
[0031] Although the invention herein has been described with reference to particular embodiments, it is to be understood that these embodiments are merely illustrative of the principles and applications of the present invention. It is therefore to be understood that numerous modifications may be made to the illustrative embodiments and that other arrangements may be devised without departing from the spirit and scope of the present invention as defined by the appended claims.
INDUSTRIAL APPLICABILITY
[0032] The apparatus of the present invention provides plumbing fixtures, in particular shower heads, which are usable with a number of different flow rates, while maintaining the appropriate water pressure at each such flow rate. This provides improved and environmentally appropriate shower heads for home and industrial usage. | A multiple flow shower head ( 1 ) is disclosed including a body (Ia) for directing a flow of water, an outlet with a plurality of outlet channels ( 12 a, 12 b, 12 c ) corresponding to a plurality of water flow rates, a rotatable sheath ( 20 ) for switching the flow of water through a selected outlet channel, and a corresponding plurality of pressure compensators ( 3 ) disposed in the plurality of outlets channels in order to stabilize the flow of water at various flow rates. | 1 |
FIELD OF THE INVENTION
The present invention relates to a system and display for providing information to elevator passengers, and, more specifically, to a system and display for providing information to elevator passengers that includes virtual call data.
BACKGROUND OF THE INVENTION
Today, high buildings are almost invariably provided with several elevator banks, each of which can transport passengers to different parts/different floors and zones in the building. One elevator bank typically comprises 4–8 elevators. The operation of the elevators comprised in the elevator bank is controlled by a group control system of the elevator bank, which receives landing calls for the elevators in the elevator bank. Landing calls are issued to the group control system via landing call input devices, such as landing call keys, or they are virtual calls obtained from a data processing system. In addition to landing call input devices, calls can be given in most elevator systems by means of car call input devices provided in the elevator cars, but these calls are generally not transmitted to the group control system of the elevator bank. The landing call input devices on different floors are generally up/down call keys placed outside the elevator bank, which are common to all the elevators in the elevator bank, although in some systems the landing call input devices on the floors are floor call devices used to give a desired destination floor. The landing call keys used in the entrance hall are invariably floor call keys.
After the calls have been transmitted to the group control system by any method, the said group control system will allocate these group calls to the elevator control systems comprised in the elevator group by utilizing a suitable control algorithm. In general, the control algorithm aims at minimizing the passengers' call time and/or journey time. After this, the elevator control systems carry out the group calls assigned (allocated) to them, yet also taking the car calls issued from the elevator car into account. In some cases the elevator group is implemented using only elevator group specific landing call input devices at the floors and lobbies but no car call input devices in the elevator cars. Thus, in these control systems, no car calls are given at all; instead, all calls are landing calls, which the group control system receives, processes and distributes to the lower-level elevator control systems.
In this context, “elevator group” and “elevator bank” refer to two or more elevators which are situated close to each other and have common landing call input devices and whose operation is coordinated by a common group control system.
“Landing call” here refers to a call transmitted to the group control system from outside the elevator car. A landing call may also consist of a completely virtual call produced by a data processing system.
“Car call” refers to a call issued from inside the elevator car.
“Call” in general again refers to a landing call, car call or virtual call. A virtual call is a call produced by a data processing system and is therefore not necessarily related to calls produced by actual persons. However, virtual calls are generally produced by a logic that emulates calls given by actual persons as realistically as possible.
The ease of transport and the length of total traveling time from an elevator lobby in a building having one or more elevator banks to different floors are dependent first on the call time, i.e. the time from the instant the passenger has given an elevator call until the instant when an elevator going in the right direction arrives at the passenger's floor. In addition, the length of the total traveling time on the elevator ride time, i.e. the time from the instant the person enters the elevator to the instant when the person arrives at the desired destination floor. Moreover, the total traveling time is often increased by a time of transition from the entrance hall to the right elevator bank and elevator especially in large buildings. The transition time may be fairly long if the building has several elevator banks of which the person must first select and identify the right elevator bank and then find in the respective elevator bank the fastest elevator going to the destination floor. The traveling time and the call time can be reduced by technical means, such as by developing the control algorithm used in the group control system, whereas the transition time can not be reduced by merely developing the group control system of the elevator bank, because it involves a time delay that is primarily dependent on the spaces in the building and the quality of the guidance systems intended to guide the passengers.
In a guidance system known from specification “TMS9900 System with Destination Consultation Stations”, written by Marja-Liisa Siikonen and Johannes De Jong, a display board placed above each elevator in the elevator bank and showing the floors to which the respective elevator is going is used to reduce the transition time.
However, a display board like this does not eliminate the problem arising from the circumstance that a person cannot find the right elevator bank at all in a complex building having several elevator banks or that the passenger further has to select the right elevator from among a relatively large number of elevators in a bank.
SUMMARY OF THE INVENTION
The present invention aims at eliminating the problems encountered in prior art. Thus, the object of the invention is to achieve a guidance system that allows the time required for transition to an elevator bank to be significantly reduced while helping passengers to quickly choose the right elevator in an elevator bank.
The guidance system of the invention comprises means for producing call data and means for transmitting call data to the group control systems of one or more elevator banks, which control systems process the call data to produce group call data and allocate said group call data to the elevator control means of the elevator bank. The guidance system comprises a display device used to show group call data of one or more group control systems.
The display device of the invention comprises receiving means for receiving group call data coming from one or more group control systems and the display elements of the display device form a unitary display, which is used to display at least the floor call data comprised in the aforesaid group call data for the elevator bank. Floor call data includes elevator identification data and destination floor data. The elevator identification data may comprise elevator car and/or bank data and/or elevator lobby data.
The passenger is thus shown the floor allocation data for several elevators on the same display. This provides the notable advantage that the passenger can quickly check which is the right elevator bank and elevator lobby if the building has several elevator banks. In the invention, the display of the same display device can be used to display the destination floor data for all elevators in the elevator bank, thus making it easy for the passenger to select an elevator going to the right floor.
In a preferred embodiment of the invention, the display device is also used to display the times of arrival of elevators at the elevator lobby, traveling times to different floors, elevator status data and data indicating whether a given elevator is working in destination mode or in normal mode. The elevator status data comprise e.g. data indicating elevator maintenance breaks, faults, etc. “Destination mode” again means that no car calls to destination floors can be issued from the elevator car, so the elevator will go to different floors only on the basis of calls transmitted to the group control system. “Normal mode” means that car calls to destination floors can be issued from the elevator car. The display device of the invention again affords the considerable advantage of enabling the passenger to quickly verify which elevator will provide the fastest ride to a given floor. From the point of view of the group control system, this display device provides several advantages: passengers can be guided by the display to use the right elevators; passengers going to congested floors receiving the largest numbers of destination floor calls can be guided to use elevators operated in destination mode and only stopping at these floors, whereas other users can be guided to use elevators in which it is possible to give car calls from the elevator car.
In another preferred embodiment of the invention, some of the floor call data presented on the display of the display device are virtual floor call data, in other words, data referring to virtual floor calls, which are converted into real calls by the car call input devices in the elevator cars. Such a display device provides the advantage that the operation of the call input devices and the display device can be easily changed according to the numbers of passengers; in peak traffic hours, such as in the morning and in the evening, it is possible e.g. to allow the use of landing call input devices only and inactivate the car call input devices, thus causing the elevators to operate in destination mode only. Outside peak hours it is possible to enable the operation of both landing call input devices and car call input devices, in which case both landing calls and possible car calls will be shown on the display. In patent specification GB 2241090, Godwin describes landing call input devices placed in an elevator lobby that can function during peak hours as destination floor keys used to input the number of the desired floor and as traditional up-down keys at other times.
In another preferred embodiment of the invention, some or all of the floor call data presented via the display device refer to virtual calls produced by statistical means by a data processing system. If the forecast virtual group calls are clearly representative of the real passenger traffic to different floors, then it is possible to achieve a considerable acceleration of the passenger flow by this type of system.
The use of a display device with a single unitary display also facilitates traffic between different elevator banks; when a passenger arrives in a first floor zone on an elevator of a first elevator bank and then has to move to a second floor zone, which can not be reached by the elevators of this elevator bank, the right elevator bank/elevator can be shown to the passenger by means of a display device placed on the transfer floor.
In the foregoing, only a few advantages achieved by the invention have been described. In the following, the invention will be described in detail with reference to the drawings and other additional advantages achievable by the method of the invention are described at the same time.
BRIERF DESCRIPTION OF THE DRAWINGS
FIG. 1 visualizes the generation of group call data and their transfer to a display device used in the guidance system of the invention.
FIG. 2 presents a display device according to the invention, designed for one elevator bank.
FIG. 3 presents a display device for one elevator bank according to the invention, used to give passengers additional information about elevator arrival times at floors.
FIG. 4 presents a display device according to the invention designed for several elevator banks.
DETAILED DESCRIPTION
FIG. 1 presents a simplified representation of the generation of group call data and their transfer to the display device 1 used in the guidance system of the invention. The guidance system is used to generate, collect and display floor call data for the elevators of to two different elevator banks. In the guidance system, the functions of the elevators of the two elevator banks are controlled by two different group control systems 7 : 7 ′ and 7 ; 7 ″, which control the operation of the elevators comprised in the respective elevator banks via the elevator control system 3 . The group control systems 7 receive floor-specific call data from call input devices 2 , distribute the received call data to the elevator control systems and then send information regarding the group calls allocated to the elevator control systems to the display device 1 . Each individual group call data comprises at least elevator identification data 3 ; 3 a and destination floor data 4 , i.e. data indicating the destination floors allocated to the elevator in question.
Connected to the first group control system 7 ; 7 ′ shown on the left are four elevators, which are controlled by separate elevator control systems 3 ; 3 ′ of the aforesaid elevators. Connected to the group control system 7 ; 7 ″ on the right are two elevators, which are controlled by the elevator control systems 3 ; 3 ″ of these elevators.
Each group control system receives landing calls 8 from the call input devices 2 . Group control system 7 ; 7 ′ receives landing calls 8 ; 8 a ; 8 a′ from the landing call input devices 2 ; 2 ′ on the left, and group control system 7 ; 7 ″ receives landing calls 8 ; 8 a ; 8 a″ from the landing call input devices 2 : 2 ″ on the right. The group control systems 7 process the landing calls 8 ; 8 a according to their own control algorithm and then allocate these landing calls to the respective elevator-specific control systems; 3 ; 3 ′ 3 ″. The group control systems 7 ; 7 ′, 7 ″ of the elevator banks send the information regarding landing calls 8 ; 8 a allocated to elevators further as group call data 8 ; 8 b ; 8 b′ , 8 b″ to the display device 1 . The group call data 8 ; 8 b comprise elevator floor call data 8 ; 8 d containing the identification data 3 ; 3 a of at least one elevator in the elevator bank, identified e.g. according to elevator door, and additionally data indicating to which floors the identified elevator has been allocated, i.e. the destination floor data 4 for the elevator. As there may be display devices 1 disposed in different locations and on different floors in the building, the allocated floor call data 8 ; 8 d to be displayed are fitted according to the location of the display device. The group call data 8 ; 8 b may also comprise other elevator group specific information as will be explained in the examples described below.
The control systems 3 of the elevators execute the landing calls allocated to them by the group control systems 7 . Car calls can also be carried out from some or all of the elevators, and the car call data 8 ; 8 c can be displayed via the display device 1 if desirable. The car call data 8 ; 8 c sent to the display device 1 are represented in FIG. 1 by a broken line. In the figure, the car call data have been sent from elevator control system 3 ; 3 ′; 3 ′ 1 . The car call data include elevator/elevator group identification data and data indicating the floor to which the identified elevator has been allocated (destination floor data).
In the display 11 of the display device 1 presented in FIG. 2 , designed to show the floor call data 8 ; 8 d for one elevator group, the first column displays elevator identification data 3 ; 3 a ; 3 a 1 – 3 a 5 by showing the elevator door identifier A . . . E, while the second column displays destination floor data 4 and elevator status information. In the present case, only elevators A and B are available for transportation, elevator A serving floors 2 , 10 and 13 while elevator B serves floors 5 , 8 and 19 . The elevator identified by elevator door C is being cleaned, the elevator identified by elevator door D is out of service and the elevator identified by elevator door E has just now undergone a failure. Under elevator door E, the display also shows an error code, allowing maintenance personnel to easily locate and correct the fault.
From the above-described elevator-bank specific display 1 ; 11 , the passenger can easily verify that the elevator allocated for him really goes to the destination floor and is not, for instance, out of service. A display according to FIG. 1 is thus preferably placed in a location close to the elevator bank.
In the display device 1 ; 11 in FIG. 3 , the display again shows floor call data 8 ; 8 d for the elevators. The first column in the display again displays elevator identification data 3 a ; 3 a 1 ; 3 a 2 by using elevator doors, in this case doors A and B. However, the first column now additionally displays the estimated time of arrival ETA 6 ; 61 , 62 of the elevator to the floor from which the call has been issued. The second column displays the destination floor data 4 regarding the floors served by each elevator in the same way as in example 1. However, the third column now additionally shows the traveling time 5 required for each elevator to reach the destination floors 4 allocated to it. The estimated time of arrival 6 ; 61 of the elevator identified by elevator door A is 10 seconds, and the elevator serves destination floors 10 , 12 and 14 . The estimated time of arrival 6 ; 62 of the elevator identified by elevator door B is 5 seconds, and the elevator serves destination floors 8 , 10 , and 13 . A display device 1 like the one presented in FIG. 3 is designed to guide and encourage passengers to use the elevator that is most advantageous in respect of time, without actual destination control, where no car calls can be issued from the elevator car. Thus, for example, in the situation presented in FIG. 3 , for a passenger going to destination floor 10 , it would be more advantageous to use the elevator identified by elevator door A than elevator B, although the estimated time of arrival 6 ; 62 for elevator B is shorter than the estimated time of arrival 6 ; 61 for elevator A. By using elevator A, the total time for reaching floor 10 is 40 seconds, while the total time for reaching floor 10 by using elevator B is 50 seconds.
The call input devices used in connection with the display device of FIG. 3 may consist of e.g. destination floor keys provided both in the elevator car and in the elevator lobby. In actual destination control, only landing call input devices are used, which are usually destination floor keys from which the calls are transmitted via the group control system to the display device. When the group control system is working in destination mode, the elevator car 1 generally has no car call input devices at all or their use is limited only to the periods outside peak traffic hours. Both the display 1 ; 11 shown in FIG. 2 and the one shown in FIG. 3 receive their group call data via call receiving elements from the elevator-bank specific group control systems 7 as illustrated in FIG. 1 . The group call data 8 ; 8 b contain at least the floor call data 8 ; 8 d for the elevators, i.e. the elevator identification data 3 ; 3 a and the calls allocated to the elevators, i.e. the destination floor data 4 for the elevators. In addition, the group call data may comprise elevator-specific additional information, such as elevator status data and estimated times of arrival.
In the case of a special call, the call input device shows the elevator identification data 3 ; 3 a to the passenger having given the call, but no destination floor data 4 for the elevator in question is shown on the display of the display device, and therefore nobody else can select this elevator reserved for a special service.
FIG. 4 presents a display device 1 placed in an elevator lobby for an elevator bank 1 and serving the elevator banks presented in FIG. 1 .
The display 11 of the display device 1 shows the elevator identification data 3 ; 3 a , indicating which elevator (defined by elevator doors A . . . D) or elevator group has been allocated to transport passengers to the destination floors 4 . The display device 1 receives the group call data 8 ; 8 b and the additional information regarding the elevators from the group control systems of different elevator banks via the receiving elements of the display device. As for the generation of group call data 8 ; 8 b , reference is made to FIG. 1 , where the landing call 8 ; 8 a is transmitted by a call input device 2 , such as floor call keys, located in the elevator lobby to the group control systems 7 a of the elevator banks 7 , and the group control systems allocate the data to the elevator control systems of the elevators in the elevator bank and then send the information regarding the allocated group calls 8 ; 8 b to the display device 1 . Some of the group calls 8 ; 8 b are virtual floor calls, which are produced by computer software. The virtual, predicted floor calls 8 ; 8 e are shown underlined on the display 11 . If the predicted calls have to be acknowledged using elevator car specific call input keys, then the information regarding these car calls is also passed via the group control system to the display device.
The receiving elements of the display device comprise data collecting and processing means, such as a microprocessor connected to the display via a suitable data bus. The aforesaid group call data 8 ; 8 b , which include floor call data 8 ; 8 d for the elevators, i.e. identification data 3 ; 3 a for identifying the elevator and/or elevator bank and/or elevator lobby and destination floor data 4 for the elevators, are subsequently displayed by the display elements 11 of the display device 1 , which constitute a unitary display. The display elements may form e.g. a plasma display, liquid crystal display or electroluminescence display, which have structures known in themselves. The floor call data 8 ; 8 d are used to present information giving the destination floors 4 of the elevators and the identification data 3 ; 3 a for the elevators allocated to the destination floors.
The display 11 of the display device 1 has two parts. The first part contains three different columns, which are used to display the destination floor data 4 and the identification data 3 ; 3 a for the elevators allocated to the destination floors, defined as elevator door identifiers. One elevator 3 ; 3 a may have several doors, the use of which is governed by the group control system for the elevator in question, so the elevator in question has several identifiers. The estimated time of arrival (ETA) 6 of the elevator defined by the elevator door at the elevator lobby or at the call floor is presented in the second part. The display device of FIG. 1 shows the group call data 8 ; 8 b for the elevators of two different elevator banks. There may be several elevators allocated to the same floor, in which case the passenger can decide from the times of arrival 6 which one of the elevators is preferable. The elevators in the first elevator bank can be used to reach floors 7 . . . 29 and the elevators in the second elevator bank to reach floors 30 . . . 36 . The elevators in the first elevator bank are identified by numbers A . . . D and the elevators in the second elevator bank by number 2; for the second elevator bank, no specific elevators are given. For elevator A, passengers have been allocated from the elevator lobby to floors 7 , 14 and 28 . For elevator B of the same bank, passengers have been allocated from the elevator lobby to floors 2 , 22 and 23 , for elevator C to floor 22 and for elevator D to floors 10 , 11 , 18 . In addition, for the elevators in the second elevator bank, which are defined by the number “2” on the display, passengers going to floors 34 , 35 , 36 have been allocated. For the second elevator bank, no specific elevators or times of arrival are given because this elevator bank is situated in a different location.
If the display 11 of the display device 1 already shows an identified elevator/elevator door reserved for the destination floor desired by the passenger, instead of having to use a call input device the passenger can directly select an elevator already reserved (allocated) to take passengers to the destination floor. If passengers having given no call are felt to be a problem, the floor call data 8 ; 8 d to be presented on the display 11 of the display device 1 can be shown with a delay so that passengers having given a call can move to the door of the right elevator before others become aware of the allocation made.
The display 1 described above also shows floor call data 8 ; 8 d obtained from the group control system 7 ; 7 a ; 7 a″ of the second elevator bank presented in FIG. 1 , but such data are not displayed separately for each elevator but only at the elevator bank level. In the floor call data 8 d relating to the second elevator bank, the elevator is only identified by referring to the elevator bank by the number “2”. However, it would be advantageous to present elevator-specific floor call data for the second elevator bank is the display 1 ; 11 illustrated in the figure were located on a so-called transfer floor, where passengers transfer from the first elevator bank to the second elevator bank. In this case, the passenger would only have to give one floor call 8 in the elevator lobby of the first elevator bank and it would be possible to send an elevator of the second elevator bank to the transfer floor beforehand so that it would be ready for the passenger and be shown on the display of the display device on the transfer floor. In this way, passengers could give a call at any floor to any floor even if they had to change elevators one or more times on the way. The display device 1 of the invention allows the passenger to continuously keep track of which elevator and which elevator bank he should go to next.
The display device presented in FIG. 4 provides the advantage, especially in peak traffic hours, that all passengers need not necessarily give an elevator call; instead, they can check directly from the display device 1 whether a suitable elevator is going to their destination floor. Giving a call always takes a few seconds per passenger, so the display device allows passengers to get sooner on board of an elevator especially during inbound peak hours.
The above-mentioned predicted floor calls 8 ; 8 e are obtained by gathering traffic statistics about the use of the elevators in different elevator banks in the building and compiling traffic statistics from the passenger flows and deducing from these statistics the probable destination floors at given times by a method known in itself, such as by using suitable genetic algorithms having a learning capacity, as described e.g. in “TMS9900 System with Destination Consultation Stations” by Marja-Liisa Siikonen, Johannes De Jong. The predicted floor call data 8 ; 8 e can be combined with monitoring of arrival of passengers in the elevator bank lobby. The frequency of passenger arrivals is observed e.g. by means of personal wireless devices as described in GB patent specification GB 2241090, and for the arriving passenger a call is executed which is displayed on the display 11 of the display device.
If the floor call data 8 ; 8 d presented on the display of the display device consist partially or completely of predicted data and the predicted calls correspond closely to actual floor calls given by passengers, then the landing call input devices 2 in the elevator lobby may be conventional elevator-bank-specific up-down keys, and elevators called in this manner do not necessarily even need any elevator-car-specific car call input devices, or these devices can be inactivated during peak traffic hours. In a fully automatic system, all the floor calls presented on the display of the display device are predicted calls 8 ; 8 e . In practice, an elevator control system based on predicted calls can primarily be used for controlling some of the elevators in an elevator bank during morning peak hours.
In the foregoing, only a few preferred embodiments of the invention have been described, but it is obvious to the skilled person that the invention can be implemented in many other ways within the scope of protection defined in the claims.
Thus, the display 1 in FIG. 3 shows only one estimated time of arrival (ETA) 6 at the elevator lobby from where the elevator call has been given, but it can also be used to present other information regarding the elevators, such as e.g. information about the movement of the elevators. | A system and display for providing guidance to elevator passengers generates call data and transmits the call data to the group control systems of one or more elevator banks. The group control systems process the call data to produce group call data and distribute the group call data to an elevator controller of the elevator bank. The guidance system also includes a display device which displays the group call data for one or more group control systems. | 1 |
CROSS-REFERENCE TO RELATED APPLICATION
This is a divisional application of my copending U.S. application Ser. No. 089,209, filed Oct. 29, 1979, now U.S. Pat. No. 4,354,086, granted Oct. 12, 1982, which in turn is a continuation of my U.S. application Ser. No. 905,477, filed May 12, 1978, now abandoned.
BACKGROUND OF THE INVENTION
The present invention relates to a new and improved construction of transport installation and method of transporting can bodies for a fully automated resistance welding machine, which is of the type comprising a roll former station for rolling the blanks into bodies, two successively arranged driven transport systems, and a pair of electrode welding rolls or rollers.
In German Patent Publication No. 2,103,551 there is taught to the art a transport installation for can bodies wherein rolled blanks, formed into can bodies, are moved out of a roll former station by means of a continuously driven transport chain equipped with fixed catches or cams up to the region of the electrode rolls and at that location are entrained by a pawl feed and through the remaining quite short path are brought up to the welding speed and then introduced into the welding station.
Such equipment is extremely suitable for the transport of up to 300 can bodies per minute. However, at greater production capacity there arise difficulties, because at the higher chain velocity there is not sufficient time available for the rolling of the blanks between two successive catches or cams.
SUMMARY OF THE INVENTION
Hence, with the foregoing in mind, it is a primary object of the present invention to provide an improved method of transporting can bodies for a fully automated welding machine, especially a resistance welding machine, which is not associated with the aforementioned drawbacks and limitations of the prior art proposals.
Another and more specific object of the present invention aims at providing a new and improved method of transporting can bodies which is capable of handling production capacities exceeding 300 can bodies per minute, without the can bodies becoming damaged during the transport thereof by high velocity changes of the transport system.
Yet a further significant object of the present invention aims at maintaining small the mass forces in the transport system brought about by the velocity fluctuations or changes.
A further important object of the invention is directed to a novel method of transporting can bodies or the like in a resistance welding machine, wherein movement of the can bodies is controlled such that high speed transfer is possible through controlled selective movement characteristics imparted to the can bodies along different portions of the path of travel between the roll former station and the welding electrodes.
Now in order to implement these and still further objects of the invention, which will become more readily apparent as the description proceeds, the transport systems of the present development comprise endless revolving chains equipped with fixed catches or cams, the first chain passes through the roll former station where the blanks are rolled into can bodies and at which during such rolling operations the first chain cyclically and periodically comes at least approximately to standstill. The second chain has a sinusoidal velocity course, so that the intermittent, non-continuous mode of operation of the first chain, necessitated by the rounding of the blanks into the can bodies, is transformed at the second chain into a sinusoidal movement which is quieting for the bodies and with minimum velocity and changes in velocity.
Generally speaking, the method of transporting the rolled cans from the roll former station to the welding electrodes comprises providing two transport systems respectively having a first can body transfer device and a second can body transfer device. During rolling of the blanks into the can bodies the first can body transfer device is moved cyclically and periodically so that it remains at least approximately stationary in order to effectuate engagement of a rolled can body at the roll former station, whereas there is imparted to the second can body transfer device a sinusoidal movement having a velocity course such that the can bodies are transferred in a smooth fashion from the first can body transfer device when it is at least approximately at standstill or in the region of its lowest velocity course, to the second can body transfer device, whereafter the engaged can bodies are then moved at a greater velocity towards the welding electrodes for engagement thereby and performance of the welding operation at the requisite welding speed.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will be better understood and objects other than those set forth above will become apparent when consideration is given to the following detailed description thereof. Such description makes reference to the annexed drawings wherein:
FIGS. 1 to 5 schematically illustrate in side view a transport installation constructed according to the teachings of the present invention and respectively showing five successive transport phases during the operation of such transport installation;
FIG. 6 is a cross-sectional view of the transport installation shown in FIG. 1, taken substantially along the line V1--V1 thereof; and
FIG. 7 are velocity graphs for the two transport systems and the welding electrodes as a function of time.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Describing now the drawings, in FIG. 1 there is illustrated an exemplary embodiment of transport installation 1 constructed according to the teachings of the present invention, which is of the type comprising a first transport device 3 shown in the form of an endless chain 11 and a second transport device 4 shown in the form of an endless chain 23. The first transport device 3 passes through a roll former apparatus or station 6. The roller former station 6, as is well known in the art, constitutes one of the processing stations of the automated resistance welding machine, and serves to roll the blanks into the can bodies. Details of the roll former station 6 are unnecessary for understanding the principles of the present invention, and it is to be understood that any suitable roll former station 6 capable of carrying out the contemplated function described above can be used. Continuing, the transport devices 3 and 4 are driven by any suitable common drive motor M. More specifically, the common drive motor M will be seen to drive two separate cam drive gears or gearing means G 1 and G 2 , wherein the cam drive gearing G 1 drives the first transport device 3 and the cam drive gearing G 2 the second transport device 4. The cam drive gears or gearing drives G 1 and G 2 are commercially available cam drives, for instance of the type manufactured by Ferguson Machine Company, 11820 Lackland Road, St. Louis, Mo., and known as Ferguson Indexing Drives. These cam drive Gears G 1 and G 2 impart the desired motion to the first and second transport drives or systems 3 and 4, respectively, as will be explained more fully hereinafter. In particular, a sprocket wheel or gear 9 is driven by the cam drive gearing G 1 in order to impart to the first transport device or transport system 3 a desired sinusoidal-like motion, to be discussed more fully hereinafter in conjunction with FIG. 7, and the chain 11 of such transport device 3 is moved so as to have a sinusoidal velocity course where, when the chain 11 moves through the roll former station 6, during rolling of the blanks into the can bodies, it cyclically and periodically remains at least approximately stationary. The chain 11 has four fixed catches, here in the form of four entrainment members 12, 13, 14 and 15, although obviously a different number of such entrainment members can be used depending upon the system design. The chain 11 is guided about two deflection sprocket wheels or gears 16 and 17.
Continuing, the second transport device or transport system 4, which follows the first transport device or system 3, is driven, as mentioned, by the same drive motor M through the agency of the cam drive gearing or gearing drive G 2 which acts upon the sprocket wheel or gear 41. Trained about this sprocket wheel or gear 41 is the chain 23 having the catches or cams, here shown as entrainment members 24, 25, 26, 27, 28, 29 and 30, and again a different number of such entrainment members is usable depending upon the system design. The chain 23 is guided over a further deflection sprocket wheel or gear 21. The spacing of the entrainment members 24 to 30 along the chain 23 is smaller in the case of the transport system 4 than for the transport system 3, and specifically by a factor of 0.5, to 1.0, preferably 0.8. Following the transport device or system 4 are electrode welding rolls or rollers 32 and 33 of the electrode welding station.
Now in FIGS. 1 to 5 there have been conveniently shown five sheet metal bodies 35, 36, 37, 38 and 39. FIG. 1 illustrates the start of an infeed and transport cycle of the can body processing operations. The rolled blank forming a can body 35 which has just been rolled into such rounded can body, is located directly before the start of its transport by the entrainment member 13 of the transport system 3. This phase of operation corresponds to point A 1 in the diagram of FIG. 7.
The second can body 36 is moved by the entrainment member 24 of the second transport system 4 at approximately the maximum velocity in the direction of the welding rolls 32 and 33. This operation corresponds to the point A 2 of the diagram of FIG. 7.
The next can bodies 37 and 38 are moved by two further entrainment members 25 and 26, whereas the can body 39 is located at the welding station containing the welding rolls or rollers 32 and 33.
Now according to the showing of FIG. 2 the entrainment member 13 has just engaged the can body 35 at the roll former station 6. This operation corresponds to point B 1 of the graph 55 shown in the diagram of FIG. 7. The welding of the can body 39 proceeds in a direction opposite to its end 39a.
Turning attention now to FIG. 3, the transport system 3 is at the phase of maximum velocity. This corresponds to the point C 1 of the graph 55 of FIG. 7. The transport system 4 is just in the process of displacing the rolled can body 38 between the welding rolls 32 and 33, this being accomplished at the welding speed. Such corresponds to the point C 2 of the graph 57 of FIG. 7. The spacing of the blanks 38 and 39 is greater than null, but approximately equal to null. The velocity at the point C 2 amounts to between about 20 and 80 m/min.
In FIG. 4 both of the transport systems 3 and 4 have been shown in their retardation or deceleration phase. Such corresponds to points D 1 and D 2 of the graphs 55 and 57 of FIG. 7. The rolling of the next blank 34 has begun. In FIG. 5 the transport system or device 3 is stationary. This corresponds to point E 1 of the graph 55 of FIG. 7. There now has begun the transfer to the transport system 4. This transport system 4 engages the can body 35. This corresponds to point E 2 of the graph 57 of FIG. 7. After completion of the rolling operation at the blank 34 there is started the next cycle. This corresponds to the points A 1 and A 2 of the graphs 55 and 57 of FIG. 7.
In FIG. 6 there is visible a lower arm 45 as well as a Z-shaped rail 47 attached to a support or carrier 48. It will be seen furthermore that the transport system or device 4 is constructed in the form of a double chain-transport device wherein each of the chains 23 are trained about a related sprocket wheel or gear 21 arranged at opposite sides of the support carrier 48. There is further shown how the entrainment members, here the entrainment members 25 at each such chain 23 engage at the rolled body 37 in order to urge such in the direction of the welding station and between the welding rolls 32 and 33.
Reverting again to FIG. 7, there are illustrated therein, as previously explained, the different velocity courses or curves as a function of time. Thus the curve 55 constitutes the velocity curve of the first transport system or device 3 and the curve 57 of the velocity curve of the second transport device or system 4. The curve 55, while being periodic, however is asymmetrical in its configuration, in that during a time amounting to about one-half to about one-tenth of the total cycle time (depending upon the diameter of the roll bodies) the velocity of the transport system 3 practically drops to the value null. It is during this time when the sheet metal sections of the blanks are rolled into the rolled can bodies. In contrast thereto, the velocity curve 57 is practically devoid of any standstill time. It corresponds approximately to a sinusoidal curve. Its deceleration flank is longer in time than the acceleration flank, i.e. such is steeper.
Additionally, the diagram of FIG. 7 further shows the welding curve 59 which is a straight line, since the welding speed remains essentially constant. The phase shift of the transport systems amounts to about 200°. The ratio between their maximum velocities amounts to 1.0 to 2.0, preferably 1.3. The maximum transport velocity of the first transport system 3 is greater than that of the second transport system 4. It amounts to 160 to 200 m/min, preferably to about 180 m/min.
The velocity curves 55 and 57 are selected such that the resultant acceleration and deceleration values are as low as possible, while maintaining further marginal conditions. A further condition resides in that the can spacing beneath the welding rolls 32 and 33 is essentially uniform and amounts to about 0.2 to 1 millimeter.
The rounded bodies, which are still somewhat open through a spacing of about 10 to 15 millimeters in the roll former station 6, are thereafter guided over the lower arm 45 and then continuously closed by means of conventional calibration tools, as is well known in this art, so that the edges of the can bodies which are to be welded, depending upon the prevailing requirements, reach the welding rolls or rollers 32 and 33 with a small overlap. The can bodies to be welded, even with extremely high production numbers, must be moved with as small as possible velocity, acceleration and deceleration through the transport system 4. Furthermore, the movement of the transport system 4 is designed such that the can bodies, following transfer to the welding rolls or rollers 32 and 33, are not damaged by the further moving entrainment members 24 to 30 which are turned or deflected at the sprocket gear or wheel 21.
The described transport installation must be capable of accomplishing the explained functions in a continuous operation free of any disturbances and without damaging the can bodies, and the output of such installation can amount to approximately 400 can bodies per minute or more.
By optimizing the course of the movement or the motion of both transport devices 3 and 4 in accordance with the velocity curves 55 and 57, it is possible, notwithstanding the high production velocities, to obtain minimum body velocities, acceleration and deceleration. This has a particularly advantageous effect in ensuring for undisturbed course of the movement of the transport installation and the processing of the can bodies therethrough.
While there are shown and described present preferred embodiments of the invention, it is to be distinctly understood that the invention is not limited thereto, but may be otherwise variously embodied and practised within the scope of the following claims. Accordingly, | A method of transporting can bodies for a fully automated resistance welding machine comprising a roll former station for rolling the bodies, two successively arranged driven transport systems, and a pair of welding electrodes. The transport systems comprise endless, revolving chains equipped with fixed catches or cams and defining first and second chains. The first chain passes through the roll former station where, during rolling of the blanks into the can bodies, it cyclically and periodically remains at least approximately stationary, whereas the second chain has a sinusoidal velocity course. The can bodies exposed to the intermittent non-continuous mode of operation of the first chain, necessitated by the roll forming operation, are transferred to the second chain and experience a movement which is stabilizing for the can bodies. | 1 |
RELATED APPLICATIONS
[0001] None
GOVERNMENT SPONSORED RESEARCH
[0002] None
BACKGROUND OF THE INVENTION
[0003] The present invention relates generally to the field of core body temperature and circadian rhythm monitoring systems, and particularly, to a core body temperature monitoring and analysis/display systems for providing personalized suggested activities and activity timing in view of circadian synchronization and individual schedules.
[0004] The hour-to-hour fluctuation of body processes over the course of a day follows a pattern known as the Circadian Rhythm. Wake times, sleep times, meal times, exposure to light and dark, and physical and mental performance peak periods should preferably happen at certain times of the day, which correspond to points on the curve of the daily fluctuation of Core Body Temperature (CBT). The normative shape of the CBT curve is known, and when the actual measured CBT profile of an individual matches the normative shape (timing and relative amplitude), then the individual is in circadian synchrony. In the modern world with its pressures to work late, get up early and eat and exercise when time allows, circadian synchrony is difficult to achieve.
[0005] There are many health consequences of circadian de-synchrony and loss of circadian oscillatory amplitude. Examples of these health consequences include jetlag, sleep loss, weight gain, obesity, hypertension, heart disease, cancer, anxiety, depression, and the sleep disturbances associated with post-traumatic stress disorder, mild traumatic brain injury, and dementia. Many cases of these diseases could be prevented or mitigated, if circadian disruption could be easily detected and remedied. In addition, many of the medications used to treat these conditions and diseases are most effective when the medication is taken in synchrony with the circadian peak of the physiologic process targeted by the medication.
[0006] Circadian synchrony, or lack thereof, can be determined by monitoring CBT over the course of the day and night. Continuous physiological monitoring, due to advances in sensors, processors and communications protocols is becoming practical in actual daily life situations. In the case of monitoring CBT, some traditional means are not particularly practical. Rectal thermometers are obviously not suitable for daily use. Ingested thermometer/transceiver packages have been developed but these are not re-useable, are costly, and therefore, are not practical for frequent or long-term use. Tympanic thermometers that use a thermocouple can provide continuous CBT readings, however, they are not practical due to the fact that the sensor must be touching the tympanic membrane which causes discomfort and poses a risk for tympanic membrane rupture and/or injury. Single reading non-contact tympanic IR thermometers could be packaged suitable for daily use, but require a significantly different configuration for continuous monitoring applications to overcome the problems of positional variability, precision and response time that exist with currently available single-reading tympanic IR thermometers.
[0007] However with suitable sensor packaging and performance, continuous CBT monitoring over all or most of a 24 hour period has the potential to track circadian de-synchrony and potentially motivate changes in actual daily life activities and schedules where the causes of the de-synchrony originate. Currently available resources in this area include jetlag algorithms (bodyclock.com, jetlag Rx) and consumer sleep devices (SmartWatch, Zeo, etc). The jetlag and similar algorithm systems give recommendations for overcoming de-synchrony that are generic based on responses to a questionnaire. The consumer sleep devices measure activity at night such as motion or eeg to determine sleep patterns, which do correlate to part of the circadian cycle, but only the sleep portion, typically the least controllable part of the cycle. Neither provide recommendations that address actual individual data over the full 24 hour circadian cycle. It is the object of this invention to provide a system that determines circadian de-synchrony and provides mitigating measures in real-life environments over all or a significant portion of full circadian cycles.
SUMMARY OF THE INVENTION
[0008] The invention is a Personal Health Care system, which includes a wearable Core Body Temperature (CBT) monitor, containing at least one sensor, power supply and at least one communications link to a processor and display unit which contains a programmable controller, data storage, a display and at least one communications link to the CBT monitor. CBT data is collected and compared to at least one of normative or previously stored CBT data, and deviations from predetermined desirable circadian CBT synchrony and oscillation amplitude are detected and analyzed algorithmically to determine activity type and timing to restore circadian alignment and amplitude. Advice to perform the activities at the determined time is displayed and activity reminders may be scheduled.
[0009] In one embodiment the CBT monitor includes a sensor mounted in the ear, preferably at least one of a thermopile, a thermistor, or a multiple sensor arrangement of thermopiles and thermistors to provide improved signal to noise, precision and accuracy. In a preferred embodiment, the communication link between the CBT monitor and the processor and display unit is wireless, including standard wireless protocols such as Bluetooth and Zigbee. In some versions, the processor and display unit may be a standard personal appliance, including smartphones and PDAs, executing a program for the circadian data collection, algorithms, and display functions, or it may be embodied as a webpage providing display and analysis accessed by an internet gateway, or embodied as an intermediate unit connecting to a PC or the internet where the display and analysis is distributed.
[0010] In another embodiment the invention is a computerized method for analyzing and displaying circadian synchrony information for an individual. This method includes acquiring continuous or semi-continuous CBT data from an individual in normal daily activity situations, comparing at least one of real-time CBT, CBT over an interval, or CBT oscillation attributes such as transition intervals and/or amplitude to normative CBT circadian data, displaying the acquired data and the normative data to allow visual comparison between them, and providing suggested activities to reduce the desynchrony between the individual's actual CBT data and the normative data. In various versions, normative data is selectable from a choice of sources. In preferred versions, activities may be scheduled and the user alerted when the activity is due.
[0011] One aspect of the invention is a suitable display for conveying circadian data. A particular suitable display includes a 24 hour clockface with an innermost circle and at least two concentric rings superimposed on the clockface: the innermost circle showing the real-time comparison between the user's current CBT and the normative clock-time CBT; the inner concentric ring showing event markers and divided by border lines into intervals including clock-time and circadian transition intervals, and the outer ring showing corresponding event markers and divided into intervals and transitions corresponding to the inner ring. In one implementation, the outer ring may represent a normative circadian CBT cycle and the inner ring actual measured CBT data. The deviations from the normative temperatures may be represented by temperature-scaled color or texture shading variations, and shifts in interval and event timing may be represented by shifts in the markers and border lines between corresponding inner and outer ring intervals. The innermost ring and/or any interval on the user CBT ring may be selectable to represent at least one of; re-synchronizing activity and timing recommendations relevant to current CBT, or all or parts of the circadian cycle. Event markers may be chosen to represent daily events such as sunrise/sunset and the like. In preferred versions these markers will be updated based on user geographical location. The choice and emphasis of synchronizing activities displayed may be tailored to specific health goals.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] The invention will be better understood by referring to the following figures.
[0013] FIG. 1 schematically illustrates the elements of the invention
[0014] FIG. 2 is a detailed block diagram of an implementation of the system.
[0015] FIG. 3 illustrates sample CBT circadian data.
[0016] FIG. 4 is an algorithmic flow chart.
[0017] FIG. 5 is another algorithmic flow chart.
[0018] FIG. 6 is another algorithmic flow chart.
[0019] FIG. 7 shows an exemplary user display.
[0020] FIG. 8 is an example of advice provided to the user to take action.
DETAILED DESCRIPTION OF THE INVENTION
[0021] Referring to FIG. 1 , the invention is depicted at a top level, consisting of components and computer programs, combining to provide a novel health improvement system. A wearable Core Temperature (CBT) Monitor 1 is provided in a form that allows for convenient long-term use during normal daily wake and sleep activity. Preferably, Monitor 1 is an IR sensor mounted in the ear to make a non-contact tympanic measurement of CBT. Unlike most previous IR tympanic sensors, the invention preferably utilizes a continuous read (no-shutter) dual sensor thermopile/thermistor combination, which improves accuracy and precision of tympanic membrane temperature measurements. Such sensors do not use a noisy shutter, nor actually contact the tympanic membrane, and thus are more compatible with use continuously and during sleep. The Monitor 1 along with the sensor(s) includes a power supply and a communications link, preferably wireless as shown. In the inventor's preferred implementation, Monitor 1 also includes a programmable processor and data storage means, such that programmed measurement protocols executing on the processor, e.g., such as periodicity, averaging, and time stamping are performed by the monitor. Thus, preferably time-stamped, accurate CBT measurements are transmitted. However, simpler monitor implementations are also possible and fall within the scope of the invention. On the other extreme, the monitor could acquire and transmit single samples in response to a demand, leaving all of the measurement protocol to an external device. Many variations on data collection will occur to one skilled in the art.
[0022] A processor and display Device 2 is also part of the system. To achieve what the inventor considers to be the most beneficial results, Device 2 is preferably a handheld or carry-able unit, in preferably wireless communication with Monitor 1 . Thus data can be displayed along with activity advice during actual daily life scenarios. However, alternative Processor/Display implementations, such as fixed units (e.g., personal computers running the health system software) are possible and may also provide beneficial results, at least when the system user stays in a fixed location, such as the home. Several processor and display implementations are possible. One particularly attractive implementation is to use the capabilities already present in smart phones or PDAs, which have user interfaces, displays, radio communication (BlueTooth, cellular, LAN) and programmability. For instance, the Device 2 implementation could be an application running on a phone such as iPhone or Blackberry, using Bluetooth to communicate with Monitor 1 and an application executing on the phones processor and display for all data reduction and user notifications. Obviously, custom purpose-built display units, programs running on PC's (notebooks, laptops and desktops), or some combination utilizing different devices at different times and ranges with wired or wireless interfaces fall within the scope of the invention. Web browser-based implementations are also possible, allowing the data to be uploaded, processed and displayed directly to the internet by accessing a webpage. Such an implementation may be more easily implemented with a second Device, 2 , however, in the web mode Device 2 may simply be a gateway (cellular, LAN) from the Monitor to the internet. Combinations of distributing the data display and processing among fixed, mobile and web-based resources are also contemplated.
[0023] An exemplary implementation of the novel system is shown in the Block Diagram of FIG. 2 . Monitor 1 is an ear-mounted tympanic monitor with suitable casing and stabilized mounting pads. Suitable casing and mounting designs are known in the art. A dual IR thermistor/thermopile is interfaced through Analog/Digital conversion electronics to a programmable processor/storage unit, which in turn connects to a wireless/transceiver, and possibly also or alternatively to wired ports such as USB. A rechargeable power system is also preferably part of Monitor 1 . The wireless interface is preferably a low-power, local protocol such as Bluetooth, but LAN or cellular connection direct to the Internet or local networks are possible.
[0024] The processor in the Monitor may deliver data in a variety of forms, from single temperature readings up to fully reduced and analyzed results. The inventor prefers an intermediate approach taking advantage of the processor capability needed to acquire data and communicate it externally. Thus in the exemplary system, the data will be acquired, binned, checked for outliers, compared against calibration data, and time/event-stamped with the intent that the monitor provides true and accurate CBT values representing discrete time intervals. Since such data will be required for any conceivable analysis, the Monitor should not require frequent program changes once configured and calibrated. Such a division of tasks to the monitor is appropriate and convenient, leaving the analysis and user interface, which may be updated often, separated from data acquisition, which should be a relatively stable function. Sensor calibration can be accomplished using techniques known in the art.
[0025] An exemplary processor/display Device is shown at 2 . Preferably the user interface is a touch-screen display interfaced to a programmable processor/data storage device. This device supports a complementary wireless transceiver to communicate with Monitor 1 , as well as network access through LAN, cellular or both. Wired ports may be present, as is a rechargeable power supply. It should be noted that a smart phone such as the iPhone contains all of these elements, and that this part of the system could be implemented as an application executing on the phone processor. The application preferably includes display and user interface control, data analysis and algorithms, and communications. GPS and web access may also be desirable, again already available on many smart-phones.
[0026] Whatever the exact system configuration, given the availability of continuous (or near continuous) CBT data, many useful possibilities come into play. Monitor 1 makes possible the gathering of data such as shown in FIG. 3 . An Ideal CBT circadian synchrony curve is shown. Various de-synchronous CBT scenarios, including phase advanced, phase delayed and arrhythmic circadian rhythms are shown. With a continuous daily wear monitor, which is comfortable and economical, according to the invention, this type of personalized data can be available during actual daily life.
[0027] Depending on the details of the de-synchrony, much is known about what to do to bring the body back into a more healthful rhythm. For instance the following parameters, among others, may be derived from an actual CBT curve and from comparisons to an expected or normative CBT curve such as shown in FIG. 3 :
Wake to sleep transition—a sharp rise in CBT (increasing ˜0.4 degrees F./hour) that should begin at least 1-2 hours before waking, and which can be advanced, delayed or enhanced based on circadian phase response curves for light exposure, ambient temperature, carbohydrate timing, sleep duration, melatonin, etc.; Sleep to wake transition time—a sharp drop in CBT (decreasing ˜0.4 degrees F./hour) that should begin 1-2 hours before going to sleep, and can be advanced, delayed or enhanced based on circadian phase response curves for light exposure, extremity temperature, carbohydrates timing, physical activity, etc; Zenith CBT (T max ) and Zenith time—a maximum CBT plateau that should be at least 1.8 degrees F. above the CBT nadir (valley), should occur in the early evening and should last approximately 1-2 hours. These circadian parameters can be advanced, delayed or enhanced by specifically timed activities based on phase response curves for light exposure, exercise, peripheral vasodilatation (by showering), positive social interaction, wakeup schedule, etc. Nadir CBT (T min ) and Nadir time—a minimum CBT valley that should be at least 1.8 degrees F. below the CBT zenith (peak), should occur 2-3 hours before waking up and should last approximately 1-1.5 hours. These parameters can be advanced, delayed or enhanced by specifically timed activities such as light exposure, exercise, carbohydrate timing, peripheral vasodilatation (wearing socks in bed), ambient temperature, etc. Amplitude Period Peak physical performance time Peak cognitive performance time
However, to date, even though continuous wear monitoring has been proposed, it is in the context of acquiring single cycle, clinical and/or research data. By providing a sensor arrangement superior for continuous measurement with continuously available processing and display, Circadian Oscillation analyses and interpretation algorithms can guide amplitude enhancement and re-synchronization behaviors and personal time management activities (exercise, bathing, into bed, out of bed, taking melatonin, medications etc) in real-time daily life.
[0036] So as actual CBT data is acquired, algorithms can be used to identify remedial activities to suggest to a user in conjunction with unique display implementations to communicate the user's actual synchrony state and to schedule reminders for the behavioral suggestions. Sample algorithms are described below in the following paragraphs.
[0037] Exemplary cases illustrating the nature of suitable algorithms are described. It is to be understood that preferably at least three modes of functionality are envisioned; a real-time display and analysis mode, a mode based on data over any interval(s) less than 24 hours, and a mode based on near continuous data over a 24 hour period. Thus any display according to the invention should preferably support at least these three scenarios.
[0038] FIG. 4 depicts a case of real-time analysis and display for a CBT reading that is below the expected, normative. As each actual CBT reading is collected, that CBT value is compared to the normative CBT value for the current clock time. The result of that comparison is displayed to indicate whether the actual CBT is above, below, or equal to the normative CBT. Preferably the user may notice the discrepancy and input a request for information. The system may both update the real-time CBT display and also consult an internal look-up table programmed with information based on clinical circadian studies and circadian phase response curves. Thus specific sets of recommendations can be provided, tailored to the particular time of day and type of mismatch, for the individual to perform in real-time to help drive the CBT toward the normative.
[0039] FIG. 5 depicts a case where information based on an interval of time is considered. In this case, the system detects that an expected declining period of CBT, representing a wake-sleep transition, is delayed. The system displays the transition zone as out of alignment with the normative and provides advice from the look-up table, as shown in the lower right hand corner of FIG. 5 , on what actions to take to stimulate the desired transition.
[0040] FIG. 6 depicts a case where an individual's entire daily CBT cycle has been acquired for one or more days. In this example a range of analyses may be performed. As shown, the transition times, the shape of the oscillation (flattening) and the amplitude and timing of the oscillation peak (zenith) and valley (nadir) may all be compared to the normative, leading to layers of activity advice as shown in the figure.
[0041] Thus the acquisition of daily activity CBT data combined with conveniently available algorithmic analysis based on clinical circadian knowledge and phase response curves can be combined to both inform an individual of his synchrony or de-synchrony as well as provide specific real-time and whole-cycle based advice on improving synchrony. The inventor believes that such monitoring and real-life display and advice enables better daily activity decisions and planning with the potential for significant health and performance improvement.
[0042] A key aspect of the invention is a suitable user interface/display. A particularly useful display is shown in FIG. 7 . The display consists of a 24 hour clock face with an innermost circle, an inner ring and an outer ring. In the example of the figure, the outer ring typically depicts a normative CBT cycle, while the inner ring an acquired user CBT cycle data, although the display could be configured with inner and outer ring functions reversed as well. Both rings are divided by borderlines into intervals, along with marked events. The intervals may represent hours of the day, transition periods, exercise periods and others. Marked times may include wake-up, bed, meals, sunrise, sunset or other custom marks. A color, shading, or texture scheme is used which also can show CBT range over the cycle and CBT gradients such as wake-sleep. A texture based scheme is shown in the Figures to more readily conform to drawing requirements, but the inventor actually prefers a color based scheme.
[0043] In the exemplary display of FIG. 7 , the outer ring depicts the normative case, and as CBT data is acquired the inner ring will update. Thus if outer ring temperatures are shown in one color range or shading/texture range, the inner ring may show variations by going deeper or shallower in the color range or texture compared to the inner ring. For a color example, the normative could be defined as the temperature range covering a five degree span represented as dark blue on the low end to dark orange on the high end and temperature variations within shown in proportional color saturations within that color range. The inner ring could proportionally follow the same scheme for actual temperature, possibly extending beyond the normative range but following the same color saturation vs temperature curve. Obviously, shading or texture gradations could also be used.
[0044] Shifts in the event times may be depicted as shown by shifting the outer ring border lines and markers versus the inner ring lines to represent actual observed event times vs normative. Thus at a glance it is easy to see how user events line up versus normative, and by comparing colors or shading at a particular time see whether corresponding user amplitudes are higher or lower and by how much. If acquired data tracks normative, then the inner and outer ring will have the same color range and all marks and borderlines will line up.
[0045] Alternatively instead of continuous CBT update displayed, a mode may be selected where the inner ring displays a previously acquired time period, such as an entire day or average of several days.
[0046] As shown in FIG. 8 , utilizing a touch screen display, the user may touch the inner ring, actual CBT display at a point where a de-synchrony is indicated, and the re-synchronizing activity advice for that particular event or transition will be displayed. From within this advice display, the user can then choose to schedule a reminder for any of the suggested activities. Thus the novel display is very suitable to display the information described in the previously discussed flow charts, ie gradient, temperature differences, and event shifts, along with corresponding advice.
[0047] For a system with a GPS or cellular connection, the time-of-day and sunrise/sunset information could be automatically updated when traveling, or alternatively location information could be entered manually. Reminders and alerts for activity information, wake-up, medication, meals and so on, are also a useful feature which may be implemented in the display unit.
[0048] The display can be tailored to specific health goals the user selects, such as weight control, sleep improvement, mood improvement, cognitive performance, physical performance, medication efficacy, among others. Depending on the goal or goals selected, the recommended synchrony activities will prioritize and supplement the activities that specifically support the user's goal(s). For example, if weight control is a user-selected goal, re-synchronizing activities related to sleep duration, carbohydrate distribution, meal timing, and amplitude are emphasized, because these attributes of circadian synchrony most directly affect body weight. These re-synchronizing activities are preferably indicated by markers on the display, which when accessed bring up a message, such as shown in FIG. 8 .
[0049] Preferably the system also provides for a selection of possible sources for the normative synchronized rhythm that the user can select. These include but are not limited to synchronized CBT specific to the user's time zone; specific to the user's time zone, age and gender; specific to the user's personal schedule for bed, wakeup, exercise, meals and other activity times; specific to a new time zone the user is or will be adapting to; specific to user's prior in-synch rhythm, or specific to the synchronized rhythm of an aggregate population.
[0050] The foregoing description of the embodiments of the present invention has shown, described and pointed out the fundamental novel features of the invention. It will be understood that various omissions, substitutions, and changes in the form of the detail of the systems and methods as illustrated as well as the uses thereof, may be made by those skilled in the art, without departing from the spirit of the invention. Consequently, the scope of the invention should not be limited to the foregoing discussions, but should be defined by appended claims. | A personal health system which includes a suitable Core Body Temperature (CBT) monitor that can be worn for all or part of a 24 hour day and collect continuous CBT data. The CBT data is collected and compared to determine circadian desynchrony. A conveniently carried or worn processor/display unit, in communication with the CBT monitor, algorithmically determines activity types and activity timing based on the collected CBT data to improve synchrony. The activities and when to perform them are displayed to the user. | 0 |
FIELD OF THE INVENTION
The invention relates to extended Claus sulfur recovery plants and processes of the type having at least three reactors each periodically operated alternately under high temperature Claus and under CBA conditions and particularly to reactor switching units for such plants. In another particular aspect, the invention relates to such plants and processes which require fewer sulfur condensers than a prior art design. In another particular aspect, the invention relates to such plants and processes which prevent a high pressure to low pressure transition in a condenser from affecting emissions from the sulfur plant.
SETTING OF THE INVENTION
An extended Claus sulfur recovery plant comprises one or more catalytic reactors operated under high temperature Claus conditions in series with one or more catalytic reactors operated under cold bed adsorption (CBA) conditions. Under high temperature Claus conditions, sulfur formed in presence of Claus catalyst is continuously removed from the reactor in vapor phase and condensed in a sulfur condenser. Under CBA conditions, most sulfur formed is deposited and accumulated on the Claus catalyst. The sulfur is periodically removed during regeneration by effective high temperature gas flowing through the reactor and vaporizing sulfur which is withdrawn in vapor phase from the reactor and condensed in a sulfur condenser. High temperature Claus operation and regeneration can occur concurrently.
Besides condensing sulfur, shell-and-tube indirect heat exchangers used as sulfur condensers produce useful steam. In such shell-and-tube exchangers, boiler feed water in the shell side is converted to steam while in the tube side process gas containing sulfur vapor is cooled and sulfur is condensed and removed. For purposes of discussion, steam production on the shell side and gas cooling and sulfur condensation on the tube side is assumed. However, steam production on the tube side and process gas cooling and sulfur condensation on the shell side can also be used.
Where the process gas after cooling is above about 300° F., high pressure (for example, 60 psig) steam can be produced. When the process gas after cooling is below about 300° F. down to about 260° F., only low pressure steam (for example, 15 psig) can be produced. High pressure steam has many uses in plants and represents significant economic advantage relative to low pressure steam which has fewer applications. It is desirable to maximize high pressure steam production and to produce low pressure steam only when high pressure steam cannot be produced consistent with efficient and cost effective design and operation of the sulfur plant.
In extended Claus processes, sulfur condensers cooling gas for introduction in to CBA reactors typically operated at temperatures less than 300° F. generally produce only low pressure steam whereas sulfur condensers feeding high temperature Claus reactors or "warm" CBA reactors can be used to produce high pressure steam. When a reactor is alternated between "warm" and "cool" CBA and high temperature Claus operations concurrent with regenerator, a condenser feeding that reactor sometimes produces low pressure steam and sometimes produces high pressure steam.
In the type of extended Claus sulfur recovery plant in which three or more reactors are each periodically alternated between CBA and high temperature Claus conditions, conventional plant design associates a sulfur condenser with a reactor and rotates the reactor/condenser pair as a unit. Such a plant is shown in FIG. 1--PRIOR ART. TABLE A identifies reference numbers in FIG. 1 for easy identification.
TABLE A______________________________________Symbol Refers To______________________________________FURN/WHB Claus furnace (FURN) with waste heat boiler (WHB)C.sub.F Furnace sulfur condenserV.sub.a WHB bypass reheat valveR.sub.v Claus reactor (dedicated to high temperature Claus operation)C.sub.v Claus reactor condenserV.sub.b Claus reactor condenser bypass reheat valveA Claus/CBA Reactor Unit AB Claus/CBA Reactor Unit BC Claus/CBA Reactor Unit C1,1' Process gas supply to reactor from unit C.sub. v or another reactor or reactor unit 2 Alternate process gas supply to reactor unit from another reactor unit 3 Reactor effluent line 4 Condenser effluent line 5 Effluent line to another reactor unit 6 Effluent line to tail gas (TG) disposal 7 High pressure steam (HPS) line 8 Low pressure steam (LPS) line 9 Liquid sulfur (S) outlet10 Boiler feedwater (BFW) line13 Timer/controller for valves______________________________________
TABLE 1__________________________________________________________________________Switching Sequence and Steam Production in FIG. 1 Plant Reactor Condenser Cv Condenser Ca Condenser Cb Condenser Cc Position.sup.3 Steam Steam Steam SteamMode.sup.1 Period.sup.2 Ra Rb Rc From/To.sup.4 Press. From/To Press. From/To Press. From/To Press.__________________________________________________________________________A Claus 2 2 3 4 Rv/Ra 60 psi Ra/Rb 60 psi Rb/Rc 15 psi Rc/TG **A Heat Up 2 3 4 Rv/Ra Bypass Ra/Rb 60 psi Rb/Rc 15 psi Rc/TG **A Plateau 2 3 4 Rv/Ra Bypass Ra/Rb 60 psi Rb/Rc 15 psi Rc/TG **A Heat Soak 2 3 4 Rv/Ra Bypass Ra/Rb 60 psi Rb/Rc 15 psi Rc/TG **C Precool 3 4 2 Rv/Rc 15 psi Ra/Rb 15 psi Rb/TG ** Rc/Ra 15 psiB Claus 2 4 2 3 Rv/Rb 60 psi Ra/TG **.sup.5 Rb/Rc 60 psi Rc/Ra 15 psiB Heat Up 4 2 3 Rv/Rb Bypass Ra/TG ** Rb/Rc 60 psi Rc/Ra 15 psiB Plateau 4 2 3 Rv/Rb Bypass Ra/TG ** Rb/Rc 60 psi Rc/Ra 15 psiB Heat Soak 4 2 3 Rv/Rb Bypass Ra/TG ** Rb/Rc 60 psi Rc/Ra 15 psiA Precool 2 3 4 Rv/Ra 15 psi Ra/Rb 15 psi Rb/Rc 15 psi Rc/TG **C Claus 2 3 4 2 Rv/Rc 60 psi Ra/Rb 15 psi Rb/TG ** Rc/Ra 60 psiC Heat Up 3 4 2 Rv/Rc Bypass Ra/Rb 15 psi Rb/TG ** Rc/Ra 60 psiC Plateau 3 4 2 Rv/Rc Bypass Ra/Rb 15 psi Rb/TG ** Rc/Ra 60 psiC Heat Soak 3 4 2 Rv/Rc Bypass Ra/Rb 15 psi Rb/TG ** Rc/Ra 60 psiB Precool 4 2 3 Rv/Rb 15 psi Ra/TG ** Rb/Rc 15 psi Rc/Ra 15 psiA Claus 2 2 3 4 Rv/Ra 60 psi Ra/Rb 60 psi Rb/Rc 15 psi Rc/TG **__________________________________________________________________________ .sup.1 Each mode is characterized by specific flow sequence of process ga through reactors: A(Rv,Ra,Rb,Rc); B(Rv,Rc,Ra,Rb); C(Rv,Rb,Rc,Ra). .sup.2 Period describes operation of reactor in 2d position, except Precool occurs with freshly regenerated reactor in 3d position. .sup.3 Reactor position shows relative position in process stream of reactors Ra, Rb, Rc. .sup.4 Refers to source and destination of process gas in sulfur condenser. .sup.5 The steam in the shell of the condenser following the final CBA unit may be at either 15 or 60 psig or in transition. There should be no sulfur condensation in this condenser, and if it is cooled more than necessary, more fuel will be required in the incinerator, but the differences are minimal.
TABLE 1 shows steam production and operation sequences for operation of the FIG. 1 plant. In the FIG. 1 plant, reactor R v is operated only as a first Claus reactor ("Claus 1") while reactors R a , R b , R c alternate between CBA operation and Claus operation. (Note: A reactor operated under high temperature Claus conditions may be referred to as a Claus reactor; likewise, a reactor operated under CBA conditions may be referred to as a CBA reactor--both Claus and CBA reactors catalyze the Claus reaction.) A reactor previously operated under CBA conditions which is being regenerated in the second position also operates as a second Claus reactor ("Claus 2"). CBA operation in the FIG. 1 plant occurs when a reactor is in the third and fourth positions. The third position reactor, after precooling to CBA operation conditions, is generally operated as a "warm" CBA (feed temperature above 280°-300° F. or more) and the fourth position reactor is generally operated as a "cool" CBA reactor (feed temperature about 250°-260° F.) for maximum recovery. Regeneration in the second position concurrently with Claus 2 operation includes heatup, plateau, and heat soak as is known to those skilled in the art (see U.S. Pat. Nos. 4,482,532 and 4,822,591 which are incorporated herein by reference). Precooling of a newly regenerated reactor is accomplished prior to returning a reactor to CBA operation. These steps individually are well known to those skilled in the art, and from FIG. 1 and TABLE 1 those skilled in the art will fully understand the sequence of operation.
One problem with the FIG. 1 plant is that in each of the modes of operation, there is always a condenser following the final CBA reactor. The gas leaving this reactor is normally cool (less than 280° F.) with a sulfur dewpoint depression of 50° to 80° F. Therefore, no sulfur will condense from this gas above the sulfur freezing point of about 235° F. Running this gas through a condenser just cools it with no benefit (except, perhaps, the small amount of steam which would be produced) and with the detriment that more fuel gas will be required in the incinerator to dispose of the cooled tail gas.
Another problem with the FIG. 1 plant arises from the practice of switching a condenser from a high pressure environment to a low pressure environment during certain portions of the operating cycle. This practice periodically overloads the low pressure steam delivery system resulting in an increase in emissions from the plant. This problem is discussed below in more detail.
A preferred precooling method for the FIG. 1 plant is a "backstep," such as precooling in mode C following regeneration in Mode A and prior to switching to Mode B, as this method does not preload with sulfur a freshly regenerated reactor before it is placed under CBA conditions.
The three condensers C a , C b , C c are tied to both low pressure steam (LPS) and high pressure steam (HPS) headers and produce either 15 psig or 60 psig steam at various times as shown in TABLE 1. This controls the effluent temperature from the condensers feeding CBA reactors during the different parts of the cycle to accomplish high sulfur recovery levels.
In TABLE 1, it can be seen that each of condensers C a , C b , and C c of FIG. 1 must undergo a high pressure to low pressure transition (indicated by brackets) at certain points in the cycle. At the time of the transition, each such condenser is full of hot water in equilibrium with high pressure steam at 60 psig. When the steam side of a condenser is switched to produce into the low pressure steam header, a large portion of this water tends to flash into steam which may overload the low pressure steam system. The pressure in the entire low pressure steam system increases until the excess steam can be condensed, sometimes taking several hours before the low pressure steam system returns to its normal operating pressure. This pressure surge causes the condensers connected together via the low pressure steam delivery system not to provide the cooling required for feeding process gas at an optimum temperature to the CBA reactors. Moreover, during the Precool period the reactor in the final position is the one which previously was operated as a "warm" CBA in the third position. The resulting relatively high temperature process gas being fed to the final CBA reactor results in an increase in emissions from the plant since Claus conversion decreases with increasing temperature. This increase in emissions due to relatively high temperature process gas feeding the warm final CBA reactor continues, often for several hours until the condenser approaches standard low pressure steam pressure long enough for the reactor in the final position to cool down to "cool" CBA operating conditions. Moreover, the cool temperature wave moving through the catalytic reactor is slow and broad, further delaying return to low emissions.
Thus, the problem addressed by this invention may be described as an emissions affecting pressure surge in the low pressure steam system of the FIG. 1 plant which results when a high pressure to low pressure transition occurs on the steam side of a sulfur condenser and causes the condenser to fail to provide adequate cooling of process gas to a final CBA reactor.
Another aspect of the problem is that the pressure surge in the low pressure line may upset processes using the low pressure steam.
Another aspect of the problem is that the surge in the low pressure steam system can cause other condensers connected to the low pressure steam system to fail to provide adequate cooling. Since the FIG. 1 plant otherwise provides highly satisfactory performance (the use of three alternating Claus/CBA reactors provides the highest sulfur recovery of known extended Claus plants), it is desirable to generally retain the plant's advantageous features, including production of high pressure and low pressure steam while solving this problem.
It is difficult to inexpensively solve this problem because of the large volume of steam generated by a sulfur condenser when the condenser is switched from operation at high pressure to operation at low pressure. An auxiliary condenser can be added downstream of each of condensers C a , C b , and C c to produce low pressure steam, with process gas flowing through each auxiliary condenser only when lower effluent temperatures are required, and at other times, the process gas bypassing the auxiliary condensers. Since condensers are large and more expensive than reactors this represents a costly solution to the problem.
An object of the invention is to provide an improved extended Claus plant and process of the type in which at least three Claus catalytic reactors are each periodically alternated between operation under high temperature Claus conditions and operation under cold bed adsorption conditions. A further object is such a process and plant which requires only four sulfur condensers instead of five as required by the FIG. 1 plant. A further object is such a process and plant in which periodic changes of sulfur condensers from operation as part of high pressure steam delivery system to operation as part of low pressure steam delivery system does not result in an increase in emissions from the sulfur plant; also, a process and plant which does not periodically upset the low pressure steam system and thereby cause upsets in other processes connected to this steam system. Other objects and advantages will be apparent from the following description and the claims.
SUMMARY OF THE INVENTION
FIG. 1 shows a prior art plant of the type in which at least three reactor/condenser units A, B, C are alternated between Claus and CBA conditions. The plant of FIG. 1 requires five sulfur condensers. This has been discovered to be the consequence of the prior art practice of rotating a reactor with the condenser following it through the cycle of operations in the FIG. 1 plant. Since the gas leaving a CBA reactor has a depressed dewpoint, and since the final reactor in the FIG. 1 plant is maintained at a minimal temperature with a minimal temperature rise across it, the dewpoint of the gas leaving the final reactor is well below the sulfur condenser effluent temperature and may even be below the sulfur solidification temperature. Therefore, sulfur present has already been removed by adsorption on catalyst in the final CBA reactor before the process gas enters the final condenser. Thus, no sulfur can be condensed in the condenser which follows the final CBA reactor and this condenser is unnecessary. This is illustrated in TABLE 1 by inspecting the entries represented by a double asterisk.
According to an aspect of the invention, a condenser preceding a reactor is rotated as a unit with the reactor as the unit is rotated through the cycle of operations. Compared with the prior art plant of FIG. 1 and TABLE 1, this saves the installation of one condenser along with, during operation, controlling that condenser to switch between LPS and HPS steam systems.
Thus, a sulfur recovery plant comprises three or more switching units each comprising a Claus catalytic reactor which is periodically alternated between operation under effective high temperature Claus conditions and operation under effective cold bed adsorption conditions. Each switching unit comprises an inlet sulfur condenser having a gas inlet and a gas outlet and a valve bypass line connecting the gas inlet and the gas outlet of the sulfur condenser. A Claus catalytic reactor in the unit has an inlet connected in flow communication with the gas outlet of the sulfur condenser and has a gas outlet. Inlet means, selectably by valve control connects the inlet of the sulfur condenser in flow communication with a gas outlet of a Claus catalytic reactor of at least another switching unit or with a source of process gas from which sulfur will be removed, optionally a high temperature Claus reactor. Outlet means, selectably by valve control, connects the gas outlet of the Claus catalytic reactor in flow communication with an inlet of one of at least one other switching unit and a tail gas disposal line. Each inlet sulfur condenser is thus effective for selectably by valve control receiving gas from outlet means of another switching unit and each switching unit comprising a respective inlet sulfur condenser and a Claus catalytic reactor downstream thereof is rotated as a unit in operation of the plant and alternates between operation under effective high temperature Claus conditions and under effective cold bed adsorption conditions.
In accordance with a further aspect of the invention, a high pressure to low pressure transition in the plant shown in FIG. 1 is prevented from causing an increase in emissions in the invented plant. The invented plant and process are provided with means for placing a sulfur condenser undergoing a high pressure to low pressure transition in a position feeding a reactor not requiring cold process feed such that the pressure transition can be accomplished over a period of time effective for not affecting cooling effectiveness of other condensers or steam users connected to low pressure system.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 illustrates an extended Claus process and plant in which at least three Claus catalytic reactors are alternately periodically operated under high temperature Claus conditions and under cold bed adsorption conditions.
FIG. 2 illustrates an improved plant and process in accordance with the invention which eliminates need for one sulfur condenser of FIG. 1.
FIG. 3 illustrates an alternative embodiment of the plant of FIG. 2 which prevents a high pressure to low pressure transition in a sulfur condenser from causing a pressure surge in the low pressure steam delivery system which causes an increase in emissions from the plant.
DETAILED DESCRIPTION OF THE INVENTION
Reference numerals for FIG. 2 correspond to those for FIG. 1 (including number 4' which like reference numeral 4 refers to a condenser effluent line) except for reference numeral 11 introduced for the first time below in the detailed description of FIG. 2. Reference numerals for FIG. 3 correspond to those for FIGS. 1 and 2.
Referring now to FIG. 2, it can be seen that in comparison with the plant of FIG. 1, each switching unit A, B, C has an inlet sulfur condenser C a , C b , C c respectively associated therewith which is upstream of the respective catalytic reactor R a , R b , R c and that the condenser preceding a reactor is rotated with the reactor through the sequence of operations.
TABLE 2__________________________________________________________________________Switching Sequence and Steam Production in FIG. 2 Plant Reactor Condenser Ca Condenser Cb Condenser Cc Position.sup.3 Steam Steam SteamMode.sup.1 Period.sup.2 Ra Rb Rc From/To.sup.4 Press. From/To Press. From/To Press.__________________________________________________________________________A Claus 2 2 3 4 Rv/Ra 60 psi Ra/Rb 60 psi Rb/Rc 15 psiA Heat Up 2 3 4 Rv/Ra Bypass Ra/Rb 60 psi Rb/Rc 15 psiA Plateau 2 3 4 Rv/Ra Bypass Ra/Rb 60 psi Rb/Rc 15 psiA Heat Soak 2 3 4 Rv/Ra Bypass Ra/Rb 60 psi Rb/Rc 15 psiC Precool 3 4 2 Rc/Ra 15 psi Ra/Rb 15 psi Rv/Rc 15 psiB Claus 2 4 2 3 Rc/Ra 15 psi Rv/Rb 60 psi Rb/Rc 60 psiB Heat Up 4 2 3 Rc/Ra 15 psi Rv/Rb Bypass Rb/Rc 60 psiB Plateau 4 2 3 Rc/Ra 15 psi Rv/Rb Bypass Rb/Rc 60 psiB Heat Soak 4 2 3 Rc/Ra 15 psi Ra/Rb Bypass Rb/Rc 60 psiA Precool 2 3 4 Rv/Ra 15 psi Ra/Rb 15 psi Rb/Rc 15 psiC Claus 2 3 4 2 Rc/Ra 60 psi Ra/Rb 15 psi Rv/Rc 60 psiC Heat Up 3 4 2 Rc/Ra 60 psi Ra/Rb 15 psi Rv/Rc BypassC Plateau 3 4 2 Rc/Ra 60 psi Ra/Rb 15 psi Rv/Rc BypassC Heat Soak 3 4 2 Rc/Ra 60 psi Ra/Rb 15 psi Rv/Rc BypassB Precool 4 2 3 Rc/Ra 15 psi Rv/Rb 15 psi Rb/Rc 15 psiA Claus 2 2 3 4 Rv/Ra 60 psi Ra/Rb 60 psi Rb/Rc 15 psi__________________________________________________________________________ .sup.1 Each mode is characterized by specific flow sequence of process ga through reactors: A(Rv,Ra,Rb,Rc); B(Rv,Rc,Ra,Rb); C(Rv,Rb,Rc,Ra). .sup.2 Period describes operation of reactor in second position, except during Precooling in which the reactor in the third position is being cooled. .sup.3 Reactor position shows relative position in process stream of reactors Ra, Rb, Rc. .sup.4 Refers to source and destination of process gas in sulfur condenser.
Each inlet sulfur condenser is adapted with a valved bypass line 11 so as to provide bypass reheat gas for gas being fed to the reactor under Claus 2 operation, and correspondingly valve V b has been eliminated. Also, only four sulfur condensers are required since a condenser no longer occurs downstream of a final catalytic reactor in any of the modes of operation. Thus, the addition of two additional valved bypass lines and a new configuration of pipes and vessels has permitted the elimination of a sulfur condenser. Since a sulfur condenser is often physically large and more expensive than a catalytic reactor, substantial savings results.
Referring now to TABLE 2, TABLE 2 illustrates operation sequence and steam production from the FIG. 2 plant. As can be seen by comparing TABLE 1 and TABLE 2, the entries indicated in TABLE 1 by a double asterisk have been eliminated from the operation of the plant in accordance with FIG. 2 and TABLE 2. The steam production from the FIG. 2 plant, however, is substantially the same as steam production in the FIG. 1 plant (except that steam production from tail gas has been eliminated).
However, even though the FIG. 2 plant eliminates the need for one sulfur condenser relative to the FIG. 1 plant, it does not eliminate the emissions affecting pressure surge occurring at points in the cycle. This can be seen from the following discussion.
In the FIG. 1 plant, at the end of the Heat Soak Period the reactor in the second position is hot and fully regenerated, the reactor in the third position is on adsorption as a "warm" CBA reactor (feed temperature 280°-300° F. or warmer), and the reactor in the final position is on adsorption as a "cool" CBA reactor (feed temperature 260°-280° F). The hot Claus catalyst in the second position reactor must be cooled prior to switching the reactor to the final position as overall sulfur recovery is largely a function of the temperature of that portion of catalyst within the final reactor in which Claus reaction occurs. During Precool, therefore, the hot newly regenerated catalyst is placed in the third position for a limited period of time for cooling. At the same time, the "warm" CBA reactor which had been in the third position is switched to the final position, and the cool CBA reactor which had been in the final position is switched to the second position (for example, Mode C). High emissions will result in this period if the warm reactor in the final position is maintained warm. It must be cooled to "cool" CBA operating conditions to keep the sulfur emissions at a minimum. During Precool, however, the condenser feeding the reactor in the final position is the one which was making high pressure steam during the previous Heat Soak period when it fed gas to the same reactor in the third ("warm" CBA) position. To keep emissions at a minimum, at the beginning of the Precool period, this condenser must very quickly be switched to low pressure steam. Prior to switching, the hot water in this condenser is in equilibrium with steam at the higher pressure. Reducing the pressure in this condenser causes a significant fraction of this water to flash to steam at the lower pressure in order to maintain the thermodynamic equilibrium. The amount of steam thus produced is nearly independent of the rate at which the pressure in the vessel is reduced. If the condenser is suddenly connected to the low pressure steam header, the total amount of steam that would be produced from the hot water will be produced very quickly, and the steam rate produced into the low pressure steam header will be very large. In fact, it may well be so large that the users of low pressure steam on this header cannot use the steam fast enough and the pressure within the header will increase. A new thermodynamic equilibrium will be reached as the switch is made from an isolated hot high pressure condenser and a low pressure steam header to a combined system with the condenser connected to the steam header. A higher pressure in the low pressure steam header means the temperature of the steam within it will also increase. This means that the condenser being switched and the other condensers producing steam into this header will do a less efficient job of cooling and those pieces of equipment which use the low pressure steam will suddenly receive a hotter steam which may result in upsets of the control system. A solution would be to very slowly bleed pressure from the condenser being switched from high pressure to low pressure operation into the low pressure steam header at such a rate that the amount of additional steam going into it from the reduction of the pressure on the hot water is insufficient to increase the pressure within the steam header. However, if this is done for the FIG. 1 plant, the gas feeding the final CBA reactor is too warm and a period of high sulfur emissions results.
Referring now to FIG. 2, it can be seen that the FIG. 2 plant is constrained by its piping and is unable when in mode A to interchange, for example, units A and B while keeping unit C in final position; or when in mode B, is unable to interchange units B and C while keeping unit A in final position; or when in mode C, is unable to interchange units A and C while keeping unit B in final position.
The consequences of this can be illustrated by considering, as in FIG. 2, a Claus reactor R v followed by Claus/CBA reactors, R a , R b , R c which are each preceded by a condenser C a , C b , and C c and which are piped so that each reactor and condenser (C a and R a , C b and R b , and C c and R c ) rotate as a unit in sequences illustrated by TABLE 2. During the heat soak period, the sequence is R v , C a (bypassed), R a , C b (60 psig), R b , C c (15 psig), R c . This allows R a to be heated for the heat soak period of regeneration, C b to make higher pressure steam, R b to be a CBA reactor operated slightly warmer than the final CBA reactor, and C c to cool a gas as much as possible for a higher recovery in final CBA reactor R c .
When switching to the precool period, the sequence becomes R v , C c (15 psig steam), R c , C a (15 psig steam), R a , C b (15 psig steam), R b . Condenser C c should make 15 psig steam to keep temperatures low in R c which will cause more Claus reaction to occur and therefore less reaction and heat of reaction in the following CBA reactor R a which allows it to cool more quickly. Also, in the steps preceding Precool, condenser C c had been making 15 psig steam, so maintaining it at 15 psig is causes problem. Condenser C a produces 15 psig steam since it is furnishing the cool gas to do the cooling of R a . A higher pressure of steam in the low pressure steam system resulting from connecting the shell side of C b into the LPS system would prevent the reactor R a from becoming as cool L and then in the next step, R a will be placed in the final position and the recovery of the process, which is a strong function of the temperature of the final adsorption reactor, will be affected. Condenser C b is now sending process gas to the reactor R b in the final position. In the previous step, this condenser produced 60 psig steam, and the reactor following it R b is therefore warmer than optimum. This reactor R b is now in the final position and must be further cooled to maintain a high sulfur recovery (as explained above). To do this, condenser C b must now produce 15 psig steam. Therefore, the need for a sudden reduction in a condenser steam pressure still exists in this configuration, and the corresponding pressure surge in the low pressure steam system will occur.
Thus, whereas the FIG. 2 plant eliminates the need for one of the sulfur condensers of the FIG. 1 plant, the FIG. 2 plant continues to have an emissions affecting surge in the low pressure steam system.
However, by addition of valved lines 12 (connecting unit A to inlet of unit C, unit B to inlet of unit A, and unit C to inlet of unit B--see reference numerals 2'A, 2'B, 2'C indicating such connections) as shown on FIG. 3, reactor effluent from A can be fed to either of units B or C; from B can be fed to either of units A or C; and from C can be fed to either of units A or B, permitting operation in accordance with the invention.
TABLE 3__________________________________________________________________________Switching Sequence and Steam Production in FIG. 2 Plant Reactor Condenser Ca Condenser Cb Condenser Cc Position.sup.3 Steam Steam SteamMode.sup.1 Period.sup.2 Ra Rb Rc From/To.sup.4 Press. From/To Press. From/To Press.__________________________________________________________________________A Claus 2 2 3 4 Rv/Ra 60 psi Ra/Rb 60 psi Rb/Rc 15 psiA Heat Up 2 3 4 Rv/Ra Bypass Ra/Rb 60 psi Rb/Rc 15 psiA Plateau 2 3 4 Rv/Ra Bypass Ra/Rb 60 psi Rb/Rc 15 psiA Heat Soak 2 3 4 Rv/Ra Bypass Ra/Rb 60 psi Rb/Rc 15 psi Precool 3 2 4 Rb/Ra 15 psi Rv/Rb 60 psi Ra/Rc 15 psiB Claus 2 4 2 3 Rc/Ra 15 psi Rv/Rb 60 psi Rb/Rc 60 psiB Heat Up 4 2 3 Rc/Ra 15 psi Rv/Rb Bypass Rb/Rc 60 psiB Plateau 4 2 3 Rc/Ra 15 psi Rv/Rb Bypass Rb/Rc 60 psiB Heat Soak 4 2 3 Rc/Ra 15 psi Ra/Rb Bypass Rb/Rc 60 psi Precool 4 3 2 Rb/Ra 15 psi Rc/Rb 15 psi Rv/Rc 60 psiC Claus 2 3 4 2 Rc/Ra 60 psi Ra/Rb 15 psi Rv/Rc 60 psiC Heat Up 3 4 2 Rc/Ra 60 psi Ra/Rb 15 psi Rv/Rc BypassC Plateau 3 4 2 Rc/Ra 60 psi Ra/Rb 15 psi Rv/Rc BypassC Heat Soak 3 4 2 Rc/Ra 60 psi Ra/Rb 15 psi Rv/Rc Bypass Precool 2 4 3 Rv/Ra 60 psi Rc/Rb 15 psi Ra/Rc 15 psiA Claus 2 2 3 4 Rv/Ra 60 psi Ra/Rb 60 psi Rb/Rc 15 psi__________________________________________________________________________ .sup.1 Each mode is characterized by specific flow sequence of process ga through reactors: A(Rv,Ra,Rb,Rc); B(Rv,Rc,Ra,Rb); C(Rv,Rb,Rc,Ra). .sup.2 Period describes operation of reactor in second position, except during Precool in which the reactor in the third position is being cooled .sup.3 Reactor position shows relative position in process stream of reactors Ra, Rb, Rc. .sup.4 Refers to source and destination of process gas in sulfur condenser.
Referring now to TABLE 3, it can be seen that the need for a sudden 60 to 15 psi transition has been eliminated. During the heat soak period (see Mode A), the sequence is R v , C a (bypassed), R a , C b (60 psig), R b , C c (15 psig), R c . This allows R a to be heated for the heat soak period of regeneration, C b to make higher pressure steam, R b to be a "warm" CBA reactor, and C c to cool a gas sufficiently for a "cool" CBA reactor R c for maximum recovery.
When switching to the precool period, the sequence becomes R v , C b (60 psig), R b , C a (15 psig), R a , C c (15 psig), R c .
While 15 psig steam could be produced in Condenser C b to provide a lower feed temperature to R b to maximize the Claus reaction in it, and thereby reduce the heat of reaction in cooling reactor R a , it is not practical in this configuration. In the steps preceding Precool, condenser C b was making 60 psig steam as it was feeding the warm CBA reactor on adsorption. The reaction differential in reactor R a due to the difference in steam pressure in C b can be compensated for by slightly increasing the Precool time period. Condenser C a will make 15 psig steam to cool as quickly as possible the newly regenerated reactor R a . In the steps prior to Precool, condenser C c was making 15 psig steam and feeding cool gas to cool final CBA reactor R c . It can continue to do this during Precool and a cool reactor is maintained in the final position with a cool feed without the need for a sudden high pressure to low pressure transition to occur on the steam side of a condenser with the corresponding sulfur emission affecting pressure surge within the low pressure steam system.
With this invention, when the steam pressure in a condenser must be reduced (See Table 3, when a condenser is bypassed during the Heat-up, Plateau, and Heat Soak periods), a relatively long time lasting several periods (approximately 3 to 6 hours or more) is allowed for the high pressure in the condenser to be bled into the low steam pressure header without causing a sulfur emissions affection pressure surge within the low pressure steam header.
The invention is directed to solution of a particular problem in a particular type of extended Claus sulfur recovery plant The plant is one in which three reactor/condenser units are alternated between Claus and CBA operation, in which the steam production side of a condenser periodically undergoes a high pressure to low pressure transition, in which such transition affects recovery due to temperature effects within the low pressure steam system resulting in other condensers which are tied on shell side via a low pressure steam deliver system to the condenser undergoing the transition; and to a plant which produces both high pressure and low pressure steam. The invention in its various aspects eliminates the need for one of the sulfur condensers in a prior art design and permits retaining the capabilities of this plant in maximized production of high pressure and low pressure steam while avoiding increases in emissions which result from the high pressure to low pressure transition.
The invention has been described in terms of specific and preferred embodiments, but is not limited thereto but by the following claims interpreted according to applicable principles of law. | A reactor unit for use in extended Claus process plants comprising three or more reactor units, each alternating between operation under high temperature Claus and cold bed adsorption conditions, comprises a sulfur condenser upstream of an associated downstream reactor which are rotated as a unit through operations in the plant. This reduces the number of condensers required. In a further aspect, a potential surge in the plant low pressure steam system is eliminated in comparison with previous similar extended Claus plants. | 2 |
This application is a continuation of Ser. No. 340,252 filed Mar. 12, 1973, now abandoned which is a reissue application of U.S. Pat. No. 3,416,729. .Iaddend.
BACKGROUND OF THE INVENTION
This invention relates to liquid aerators of the type which are used to prevent water stagnation, to enrich the oxygen content of water to scrub waste from water or to cool water for recirculation. Such aerators usually comprise a multi-bladed axial flow impeller power-rotated by an electric motor and operable to pump water upwardly through a throat. At the upper end of the throat, the water is deflected outwardly for interface contact with the surrounding air prior to falling back into the body of water.
SUMMARY OF THE INVENTION
The present invention aims primarily to provide a new and improved aerator of the above type which, when compared with prior aerators of the same general character, produces better transfer of oxygen to the water and, at the same time, operates with increased pumping efficiency. More specifically, the invention contemplates the provision of a rotatable diffuser located at the upper end of the throat to sling the water outwardly from the throat with considerable turbulence and thereby increase the interfacial exposure of the water to the atmosphere.
Still another aim of the invention is to utilize the rotatable diffuser (1) to counteract the downthrust imposed on the bearings of the motor by the rotating impeller, (2) to reduce the danger of the water freezing and accumulating in the area of the motor, and (3) to create a higher velocity flow at the upper end of the throat to help increase the pumping efficiency.
A further object of the invention is to balance the impeller hydrodynamically to enable the elimination within the throat of bearings which otherwise would be necessary to prevent whipping of the impeller shaft. Such balancing is achieved by twisting each blade uniformly along its length and by twisting all of the blades identically so as to cause every blade to pump an equal volume of water.
The invention also resides in the novel cross-sectional shape of the blades to reduce thrust resulting from a pressure differential across the upper and lower surfaces of the blades and thereby enable most of the power which otherwise would be wasted in creating thrust to be used for effectively displacing water.
Other objects and advantages of the invention will become apparent from the following detailed description taken in connection with the accompanying drawings:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross sectional view of an aerator embodying the new and improved features of the invention.
FIG. 2 is a perspective view of the rotatable diffuser.
FIG. 3 is a bottom view showing the rotatable impeller.
FIG. 4 is an enlarged, fragmentary elevational view of an impeller constructed in accordance with the preferred embodiment of the invention.
FIG. 5 is a perspective view of a blank for twisting into an impeller blade.
FIGS. 6, 7, and 8 are cross sectional views taken along the respective lines 6--6, 7--7 and 8--8 of FIG. 4 and showing the cross section of an impeller blade and its attack angle.
FIG. 9 illustrates a cooling tank having four aerators constructed according to the embodiment of FIG. 10.
FIG. 10 is a cross sectional view of another embodiment of the invention of particular utility for cooling water.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the drawings, the invention is shown for purposes of illustration incorporated in an aerator 10 floating on a body of liquid such as water in a cooling tank, a pond or a waste treatment pool. The aerator is supported at the top surface of the water by a support or float 12 which comprises a sealed outer shell 13, the interior of which is filled with polyurethane foam 14 through a port 15 sealed by a cover 16. To moor the float in a given location, cables (not shown) may be attached to hooks 17 secured to the shell and angularly spaced around the periphery thereof.
Water is pumped upwardly from the body of water for interaction with air by an impeller 20 fixed to a vertical shaft 21 extending in a central passageway 22 in the float. The impeller shaft 21 is connected at its upper end to and for rotation by a motor 24 supported on a motor mount 25 on the shell 13. The water passageway 22 through the float is defined by a cylindrical throat or sleeve 27 disposed centrally in the float and welded to the shell 13 to keep the shell watertight. Extending downwardly from the sleeve is a hollow intake shroud 28 with an enlarged lower end through which the water is pulled from the pond by the impeller.
The water is pumped upwardly through the passageway 22 and moves horizontally beneath a stationary top plate 30 of the motor mount 25 and over the top of the float 12. The top plate is secured to the upper ends of angularly spaced legs 31 which extend downwardly from the plate 30 to an annular mounting flange 32. The latter is bolted to the shell by bolts 33 threaded into a plate on the shell 13.
In accordance with the present invention, increased efficiency of pumping and increased oxygen absorption are achieved with a low cost construction of a floating aerator. Increased oxygen absorption is accomplished in the present invention by increasing water turbulence in the air by means of a rotatable diffuser 35 which is fixed to the shaft 21 and which impinges against the water rising vertically from the passageway 22 to deflect water horizontally across the top of the float. Also, in accordance with the invention, the motor 24 is mounted above the rotatable diffuser in a manner to eliminate the need for a submersible motor and the impeller is hydrodynamically balanced in the passageway so as to eliminate the need for sealed bearings for the impeller shaft. In carrying out this hydrodynamic balancing, the impeller is formed symmetrically about the axis of the shaft and each of the impeller blades 36 is profiled in a precisely identical manner not only to afford a constant volume flow of water across the length of each individual blade but also to cause each blade to pump the same volume of water as every other blade. Increased pumping efficiency is achieved by a novel, thin blade construction which reduces the thrust due to a pressure differential caused by water particles having significant differences in velocity as they flow about the impeller blade. Moreover, the rotatable diffuser coacts with the top plate 30 to produce an air seal to prevent water from moving upwardly along the shaft 21 to the non-submersible motor 24.
Because the rotatable diffuser 35 is rotating with the impeller shaft 21, it hits the water particles and slings them outwardly causing molecular turbulence whereby noxious gases in the water are released and replaced by oxygen from the air. The impinging of the diffuser 35 on the water particles may be considered as a shearing action in which the rotating diffuser slices across the vertical rising water to shear through the same and to produce molecular turbulence and agitation increasing the rate of transfer of gases. Also, any solid waste particles impinging on the rotatable diffuser are given a scrubbing action of increased magnitude as compared with impinging against a stationary diffuser. Preferably, the diffuser 35 has a truncated conical surface 40 which is tapered upwardly and outwardly at approximately 45° to the vertical in order to deflect the water outwardly and generally horizontally through the space between legs 31. The rotatable diffuser 35 is secured to rotate with the impeller shaft by set screws 42 which are threaded to extend into a bore 43 (FIG. 2) of the diffuser 35 to engage an upper end 44 of the impeller shaft. This upper end of the impeller shaft is of a larger diameter than the lower end to afford sufficient stock for an interior and upwardly opening socket in which is received the lower end of a motor shaft 45. Suitable set screws (not shown) are threaded through the impeller shaft to engage the motor shaft so that the shafts are fixed coaxially for rotation together by the motor. The motor shaft extends upwardly through an opening 46 in the top plate 30 to the motor 24 which has its base 47 secured to the top plate 30.
To prevent water from moving upwardly through the opening 46 and along the motor shaft 45 to the motor 24, it is preferred that the rotatable diffuser 35 have its upper surface 48 disposed for rotation adjacent the top plate to create a pressure differential to drive air outwardly from between this surface 48 and the top plate 30. To increase the flow of air for sealing the opening 46 against the flow of water, the top surface 48 is formed with a plurality of raised rectangular vanes 49 which are spaced from each other and which extend radially outward from the bore 43 and across the surface 48. The air seal is of considerable importance in that it eliminates the cost of a conventional rotary shaft seal which, moreover, would be subject to attack by abrasive particles, acids or other materials carried by the water. An additional advantage obtained with the rotatable diffuser is that water is slung outwardly and prevented from curling up around the edge of the stationary plate 30 and thereby moving towards the motor as in prior art constructions. Also, the diffuser prevents the water from curling up and freezing around the plate 30.
An important aspect of the invention is to eliminate costly sealed bearings for the impeller shaft and this is achieved in the present invention by an impeller 20 which is statically, dynamically and hydrodynamically balanced. The impeller 20 is balanced and in actual practice so that tips 50 of each of the four blades may be spaced within 1/32 of an inch from the sleeve 27 forming the water passageway 22 without the shaft whipping and engaging the blades with the sleeve. Also, the hydrodynamic balancing of the impeller stabilizes the entire float against rocking in the water because the impeller functions in a gyroscopic manner and, moreover, the hydrodynamic balancing lessens the amount of vibration imparted to the motor 24. The impeller is hydrodynamically balanced by having the blades spaced at equal angles about the axis 20A of the impeller and by twisting the blades so that the same volume of water is being moved by the inner end 52 of the blade as by its intermediate portion 53 of the blade and as by the outer tip 50 of the blade. More importantly, every blade is twisted exactly the same so that each pumps the same volume of water to avoid any imbalance in the impeller. Herein, the four identically shaped blades 35 are each fixed to a hub 51 at 90° from the other. Because the outer tip end of the blade rotates at a higher speed than the inner end of the blade and because the preferred form of blade has the same width, the blades are twisted so that the attack angle with the water decreases linearly from the inner end of the blade to the outer end of the blade. In one instance, the inner end of the blade is attached to the hub at angle A (FIG. 4) of 51° and the tip end is at angle B of 80° from the vertical for a blade length of approximately three and one-half inches. As seen in FIGS. 6, 7 and 8, the intermediate portion 53 of the blade has a varying attack angle, angle C in FIG. 7, which is between the angles A and B. More specifically, the angle of attack across the intermediate blade portion changes progressively and linearly from the attack angle A to the attack angle B.
In order to increase the pumping efficiency, each impeller blade 36 is thin and flat with a generally rectangular cross section, as seen in FIGS. 6 through 8, and with its upper and lower surfaces 54T and 54G lying in parallel planes at any given portion of the blade so that the distance water particles travel across the undersurface 54G of the blade approaches the distance water particles travel across the top surface 54T of the blade whereby the velocities of the upper and lower water particles are about the same. A significant difference in velocities of water particles creates a pressure differential on opposite sides of the blades which affords a thrust acting axially of the hub. The thrust tends to move the blades downwardly without moving water and hence the power used in creating the thrust is washed and is not effectively utilized for pumping water. Herein, the thin flat blades reduces the horsepower which is wasted as a result of thrust to a minimum as contrasted to blades which have a cross section which is or closely approaches that of an airfoil. To reduce turbulence of a blade in the water, its leading edge 55 is beveled at 30° along the underside and its trailing edge 56 is beveled at 30° along the top surface. Therefore, the leading edges slice through the water and, as water particles move across the upper and lower blade surfaces, they are guided to meet at the trailing edge of the blade to reduce the bubbling turbulence which would be otherwise encountered if the water particles were not so guided toward one another.
Another and important aspect of invention is to achieve a truly hydrodynamic balanced impeller, as contrasted with prior art impellers, without expensive machining and grinding of complex surfaces. With conventional casting techniques, the impellers must be machined in order to be dynamically balanced and, in so doing, the individual blades of the impeller are often made asymmetrical from a hydraulic balancing standpoint. Herein, the low cost technique involves cutting a series of slots in the hub at the prescribed spacing, 90° apart in this instance, and at the calculated attack angle A and placing the inner ends of the blades in the slots. Then, the inner ends of flat impeller blanks 36a (FIG. 5) are welded to the hub. The impeller blank is in the form of a flat, thin, rectangular plate and the outer end of this flat plate is gripped in a die and turned to a calculated angle of attack, namely the angle B. The flat impeller blank receives a uniform twist between its tip and the hub end to afford a uniform changing attack angle C between its inner end and its tip end. As illustrated in FIGS. 6, 7 and 8, the impeller blade still affords the same thin cross section across its entire length, which, it should be noted, is unchanged from the cross section obtainable from the flat blank 36a. Thus, flat thin impeller blades 36 may be economically and identically formed with a constantly changing attack angle to give the uniform volume flow and hydraulic balance. To avoid a precise balancing of the impeller, metal is removed from the hub. The amount of metal removed is small because of the balance achieved in manufacture.
The length of trajectory of the water in the air from the diffuser 35 is important when the aerator is used for cooling towers or the like in which the transfer of heat from the water to the air is of primary importance. By increasing the length of the path of water through the air, more air interface contact is obtained, and usually over a longer period of time, thereby enabling increased transfer of heat from the water particles. In the embodiment illustrated in FIGS. 9 and 10, aerators 10a are illustrated for use in cooling towers and are of the same general construction as the aerator 10 (FIG. 1) except for slight changes now to be described. A suffix "a" is added to reference characters in FIG. 10 for elements identical or similar to those elements previously described. The rotatable diffuser 35a has a conical surface 40a which is larger than the conical surface 40 of the diffuser 35 and which is configured to throw water particles further upwardly than the rotatable diffuser 35 of FIG. 1. A stationary deflector (FIG. 10) is formed from an upwardly extending, annular baffle 70 to assist in directing the water particles along the path illustrated in FIG. 10.
Where large quantities of water must be cooled in a relatively limited space, as in a cooling tank or tower 69 (FIG. 9), a plurality of spaced aerators 10a may be floated in a body of water in the cooling tower. Each aerator 10 is open at the top to allow air to enter into a housing 71 and to cool the water particles being thrown from the diffusers 25a and 35a to the vertical sidewall 72 of the housing. The water particles stream down the housing wall to exit the housing at an opening 74 between the float 12 and the housing 71. The latter consists of a vertical sheet metal cylinder spaced above and outwardly of the float by brackets 75 which are welded to the float and housing. If space is available, the aerator 10a can be used without a housing so that the water may be thrown further outwardly for increased air contact.
To aid in understanding of the invention a brief description of operation of the aerator is given hereinafter. The electric motor 24 is connected by a suitable cable to a source of electricity and the float 12 is disposed in a body of liquid such as water. With the motor operating, the impeller shaft 21 is driven to turn the impeller 20 and pump water upwardly through the shroud 28 and passageway 22 to the rotatable diffuser 35 fixed to the shaft 21.
The rotatable diffuser 35 impinges against the vertically moving water along its conical surface 40 at an angle to deflect the water while imparting energy thereto and shearing through the water. Such impinging by the rotatable diffuser causes turbulence and interaction with the air to release gases trapped in the water which are exchanged for oxygen from the air.
The motor 24 is non-submersible and is sealed from water moving upwardly along its shaft 45 by an air seal formed by a pressure differential creased by the vanes 49 of the diffuser 35 rotating adjacent the plate 30. Air is driven outwardly from the shaft opening 46 and across the surface 48 of the diffuser to prevent water from moving inwardly between the plate 30 and the top surface 48 of the diffuser to the motor shaft.
The maintenance problems of sealed impeller shaft bearings as well as their initial cost are eliminated in this invention by hydrodynamically balancing the impeller 20. The impeller is hydrodynamically balanced by affording identical and symmetrically spaced blades 36 each of which drives a constant volume of water across its entire surface from its inner end 52 to its outer top end 50. A constant and infinitely changing attack angle is afforded to each blade to achieve this constant volume flow.
Pumping efficiency is increased by a novel blade configuration and impeller construction in which flat thin blades are twisted to afford the continually changing angle which affording a thin cross section reducing axial thrust on the blades due to difference in velocities of water particles moving at a different velocity across the lower surface of the blade than across the upper surface. Also, the edges of the blades are beveled to reduce turbulence. The increased pumping efficiency permits the use of an impeller with a greater pitch in conjunction with a motor of given capacity to produce a greater volume of flow and, when desired, enables the attainment of water velocities necessary to maintain suspension of particles in the water for scrubbing of the particles.
The water impinging on the rotatable diffuser 35 exerts a lifting force on the impeller shaft 21 to offset the downward thrust being imparted by the impeller 20 to the bearings in the motor which rotatably support the impeller shaft 21 and impeller. This lifting force of the water on the diffuser 35 is found to be quite significant in reducing the thrust loads on the motor bearings thereby further reducing maintenance problems and increasing the life of the motor bearings.
From the foregoing it will be seen that hydrodynamically balanced impeller affords a low cost and inexpensive construction and more efficient pumping of a liquid. Also, the rotatable diffuser increases the efficiency of operations such as oxygen transfer, cooling and scrubbing. | A floating liquid aerator includes an axial flow impeller rotated by an electric motor and disposed within a tubular throat to pump water from a pond upwardly through the throat and against a rotatable diffuser which slings the water outwardly for interface contact with the surrounding atmosphere. Being rotatable, the diffuser slings the water into the atmosphere with considerable turbulence thereby exposing more of the water droplets to the atmosphere and resulting in a higher transfer of oxygen to the water. The impeller comprises a series of angularly spaced blades formed with a rectangular cross-section to reduce power losses caused by drag and to increase the volume of water capable of being displaced by the impeller. Each blade is twisted longitudinally with a progressively decreasing attack angle from its root to its tip and, in addition, all of the blades are twisted identically to provide a statically, dynamically and hydrodynamically balanced impeller. .Iadd. | 2 |
RELATED APPLICATIONS
This is a 35 U.S.C. § 111(a) application of provisional U.S. patent application Ser. No. 60/042,797, filed Apr. 7, 1997.
BACKGROUND OF THE INVENTION
I. Field of the Invention
The present invention relates to satellite communications. More particularly, the present invention relates to beamforming in a satellite communication system.
II. Description of the Related Art
Fundamentals of Beamforming
The term beamforming relates to the function performed by a device in which energy radiated by an aperture antenna is focused along a specific direction in space. The objective is either preferentially receiving a signal from a particular direction or preferentially transmitting a signal in a particular direction.
For example, in a parabolic antenna system, the dish is the beamforming network since it takes the energy that lies within the aperture formed by the perimeter of the dish and focuses it onto the antenna feed. The dish and feed operate as a spatial integrator.
FIG. 1 is a diagram of a prior art, multi-beamforming, satellite communication network. In FIG. 1, ground gateway station (100) sends a combined voice and data signal (102) via the RF feeder link to the satellite (106). This signal is received by a multibeam antenna on the satellite and then transmitted to the beams within the footprint via the RF terminal links (108, 112, and 114). The part of the signal that corresponds to a particular beam is routed to that beam. Each beam corresponds to a specific frequency range that depends on the total bandwidth, channel bandwidth, and reuse factors.
Energy from a far-field source, which is assumed to be aligned with the antenna's preferred direction, arrives at the feed temporarily aligned and is summed coherently. In general, sources in other directions arrive at the feed unaligned and are added incoherently. For this reason, beamforming is often referred to as spatial filtering.
Beamforming may also be carried out using phased-array antennas. An array can be considered as a sampled aperture. When an array is illuminated by a source, samples of the source's wavefront are recorded at the location of the antenna elements.
The outputs from antenna elements may be subjected to various forms of signal processing. In these cases, phase or amplitude adjustments are made to produce outputs that provide concurrent angular information for signals arriving from several different directions in space. When the outputs of the elements of an array are combined via some passive phasing network, the phasing will usually arrange for the output of all the elements to add coherently for a given direction. If information were desired regarding signals arriving from a different region in space, another phasing network would have to be implemented.
The network that controls the phases and amplitudes of the excitation current is typically called the beamforming network. If beamforming is carried out at a radio frequency (RF), the analog beamforming network typically consists of devices such as phase shifters and power dividers that adjust the amplitudes and phases of the elemental signals to form a desired beam. The beamforming network can be implemented using microwave lenses, waveguides, transmission lines, printed microwave circuits, and hybrids.
It is sometimes desirable to form multiple beams that are offset by finite angles from each other. The design of a multiple-beam beamforming network, known as a beamforming matrix, is much more complicated than that of a single-beam, beamforming network. In a beamforming matrix, an array of hybrid junctions and fixed-phase shifters are used to achieve desired results.
Beamforming can be performed either on the ground or on the satellite. There are several advantages with having beamforming performed on the ground. A ground beamforming system releases some satellite load while allowing more beamformers to be placed on the ground than could be placed in a satellite. Another advantage is that a beamformer on the ground provides more flexibility for future tuning and modification if a failure or error occurs. Also, the number of ground-based beamformers can be increased if the need arises. This option is not available if the satellite has already been launched.
FIG. 2 illustrates a block diagram of a prior art system using ground-based beamforming. The beamforming network can be implemented by either analog or digital circuits.
In the ground based beamforming network (200), multiple ground radio transmitters (202-204) send beam signals to the beamforming network (206) that are designated to particular beams. The beamforming network (206) manipulates these beam signals into feed RF signals (208) that are routed to the multiplexer (210). The multiplexer combines the multiple feed input to a single information stream.
This information stream is input to a feeder RF front-end module (212). The feeder RF front-end (212) converts the signals to the proper RF frequency for transmission by the ground based antenna (214).
The signals are transmitted from the ground based beamforming network (200) to the space segment (220) over the feeder link (216). The space-based feed link antenna (218) receives the multiplexed signal.
The receiver RF front-end band-pass filters the antenna signal and preamplifies the signal using low noise amplifiers. The signals are preamplified to a required signal strength.
The signals from the RF front-end (225) are input to the demultiplexer (235). The demultiplexer (235) breaks out the individual feed signals that were multiplexed during the ground processing for transmission via the feeder link. Each feed signal is input to the frequency conversion section (240) where each signal is converted with a common local oscillator signal. The resulting frequency converted signals are input to the multi-beam/multi-feed antenna array (250) for transmission to the earth.
Signals radiated from multiple feeds will form beams pointing to different directions based upon the phase relationship between coherent signals at the phased array. These beams are directed to cover the service area on earth through a frequency reuse plan.
Multiple ground gateway stations are used to provide connectivity from the satellite network to the ground communications network. This eliminates the single point of failure and provides a local landing point to reduce use of long distance ground transmission facilities.
In the case of the multi-feed/multi-beam beamforming systems, it is well known in the art that all signals go to antenna feeds that form a common set of beams that must be coherent. In other words, those feed signals must be beamformed from the same ground gateway station. This places a restriction on the beamforming system that all the beams formed for one particular frequency band must come from a single ground gateway.
Fundamentals of Digital Beamforming
Beamforming functions can be achieved in the digital domain, especially when the original signal is in digital form (e.g., signals from a digital radio). Digital Beamforming is a combination of antenna technology and digital technology. A generic, digital beamforming antenna system is comprised of three major components: an antenna array, a digital transceiver, and a digital signal processor (DSP).
In a digital beamforming antenna system, the received signals are digitized at the element level. Digital beamforming is based on capturing the radio frequency (RF) signals at each of the antenna elements and converting them into two streams of binary baseband signals known as the in-phase (I) and quadrature-phase (Q) channels.
Included within the digital baseband signals are the amplitudes and phases of signals received at each element of the array. The beamforming is accomplished by weighting these digital signals, thereby adjusting their amplitudes and phases, such that when added together they form the desired beam. This function, usually performed using an analog beamforming network, can be done by a special purpose DSP.
The key to this technology is that the receivers must all be closely matched in amplitude and phase. A calibration process that adjusts the values of the data stream prior to beamforming accomplishes the matching.
One advantage of digital beamforming over conventional phased arrays is the greatly added flexibility without any attendant degradation in the signal-to-noise ratio (SNR). Additional advantages include:
(a) Beams can be assigned to individual users, thereby assuring that all links operate with maximum gain;
(b) Adaptive beamforming can be easily implemented to improve the system capacity by suppressing co-channel interference and can be used to enhance system immunity to multipath fading;
(c) Digital beamforming systems are capable of performing, in the digital domain, real-time calibration of the antenna system. Thus, variations in amplitude and phase between transceivers can be corrected in real time; and
(d) Digital beamforming has the potential for providing a major advantage when used in satellite communications. If, after the launch of a satellite, it is found that the satellite's capabilities or performance of the beamformer needs to be upgraded, a new suite of software can be telemetered to the satellite. Digital beamforming allows both the beam direction and shape to be changed by changing the coefficients in the multiplication operations performed by the digital signal processor. Analog beamforming fixes both direction and shape by hardware components values that are not easily changed.
Digital Beamforming in Satellite Communications
In microwave communication systems, such as those used in communication satellites, networks generate antenna beam signals. These antenna beam signals are then used to drive transmit arrays that in turn form the transmit beams that send communication signals to the intended destination.
Beamforming techniques were introduced to generate electronically steerable and reconfigurable beams. Electronic antenna steering negated many of the disadvantages of mechanical steering in which an antenna was moved mechanically by either rotating itself or the entire satellite at a slow rate. This method only allowed users in a small area to be concurrently served.
Electronic antenna steering, however, provides the ability to focus on many larger areas concurrently with high gain. By controlling the phase and amplitude of the transmit signals fed onto the components of the transmit (feeder) array, the beam direction, shape, sidelobe characteristics, and the Effective Isotropic Radiation Power (EIRP), can be manipulated to the requirement of a particular application. The EIRP, as is well known in the art, is the product of the input power to the antenna and its maximum gain.
Digital beamforming in satellite communications works naturally with digital radio systems. Typical baseband digital radios (350 and 351), shown in FIG. 3, perform bit stream formatting, coding, and modulator baseband processing in the digital domain. Digital-to-analog conversion is performed after a baseband, pulse-shaping, low-pass filter. It is a straightforward design to route the output of the low-pass filter, in digital form, to the beamforming network. This eliminates the extra digital-to-analog and analog-to-digital conversion.
FIG. 3 illustrates a block diagram of a typical prior art ground-based, digital beamforming system. The digital beamforming network is coupled to baseband digital radios.
This system is comprised of n input baseband radio signals. These input signals are to be carried on n satellite beams using the same frequency band signals. The beams, 1 - n, are formed by first formatting and coding the digital radio data. The formatting and coding required depends on the technology used in the communications system. Examples of such technologies are code division multiple access (CDMA), frequency division multiple access (FDMA), and time division multiple access (TDMA).
The bit stream from the formatting and coding block is input to the transmit symbol generator (302). This block (302) generates symbols from the bits in the stream. As in the previous block (301), the symbols used depend on the communications technology used.
The symbols are input to the baseband, pulse-shaping, low pass filter (305). After filtering (305), the signals from all the beam paths are input to the beamforming matrix (310). This block (310) generates the feed signals for the individual antenna feeds.
The feed signals from the beamforming matrix are input to the multiplexer (315) for combining into a single feeder signal. This signal is modulated (320) and amplified (325) for transmission to the satellite.
In order to control the spectrum shape of the baseband signal and reduce the degree of spectrum aliasing, the digital pulse-shaping filter is often required to work at an oversampled rate of four to eight times over the baseband symbol rate. This high sampling rate imposes an additional processing requirement on the processing power of the digital beamforming networks. There is a previously unknown need for a method reducing the complexity of digital beamforming networks.
SUMMARY OF THE INVENTION
Both the baseband pulse-shaping low-pass filter and the beamforming network are linear systems. Therefore, linear system theory allows the order of the low-pass filters and the beamforming matrix to be exchanged without affecting the overall system properties. This enables the beamforming matrix to operate at a much lower sampling rate, thus reducing the computational demand on the digital signal processors performing the beamforming function.
The present invention encompasses a reduced rate beamforming network. The network uses a plurality of bit stream formatters to format and code digital information signals that are to be transmitted. The formatting and coding depends on the transmission technology used.
A symbol generator is coupled each formatter in order to generate I and Q symbols from the information signals. These symbols are input to the beamforming matrix that is connected directly to the plurality of symbol generators. The beamforming matrix generates baseband beam signals from the I and Q symbols.
A plurality of baseband, pulse-shaping, low-pass filters are connected to the beamforming matrix. Each of the filters is coupled to a different baseband beam signal from the beamforming matrix. The low-pass filters each generate an antenna feed signal from each of the baseband beam signals.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a prior art diagram for a multi-beam communication satellite network.
FIG. 2 shows a prior art high-level block diagram of a ground-based beamforming system.
FIG. 3 shows a prior art block diagram of a ground-based digital beamforming system using digital radios.
FIG. 4 shows a block diagram of the reduced rate beamforming network of the present invention.
FIG. 5 shows a block diagram of a multi-frequency, multi-beamforming system in accordance with FIG. 4.
FIG. 6 shows an implementation of the beamforming matrix of FIG. 4 in a digital signal processor.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention reduces the computational load on digital signal processors in a digital beamforming system. The beamforming network of the present invention provides a more robust and economic system by changing the order of processing within the beamforming network.
The beamforming network (400) of the present invention is illustrated in FIG. 4. The base-band, pulse-shaping filter (405) and the beamforming matrix (410) are both linear subsystems. According to linear theory, therefore, their order of processing is not important to the overall system properties.
The digital voice or data signals are input to the beamforming network (400). There are n terminal link beams and k frequency bands in the present invention. n is directly related to the frequency reuse factor. The frequency reuse factor affects the number of simultaneous independent beams that can operate at the same frequency in the system. For clarity, only frequency band 1 will be discussed since the other beams are the same.
The digital bit stream signal is input to the formatting and coding block (415). This block is responsible for taking the unformatted bit stream and formatting and coding it according to the transmission technology used. Such technologies include CDMA, TDMA, FDMA, and GSM. The formatting and coding used are defined in the corresponding standard specification.
Other transmission technologies may also be used. All of these transmission technologies are well known in the art and are not discussed further.
The formatted and coded bit stream is input to a transmit symbol generator (420) for generation of the I and Q symbols, (I, Q) n . The generation of these symbols is also well known in the art and is not discussed further.
The I and Q symbols are input to the beamforming matrix (410). FIG. 6 illustrates the implementation of the beamforming matrix processing with a digital signal processor. The beamforming column vector is denoted as b i . The beamforming matrix is denoted as B mn . The vector and matrix are:
b.sub.i ={b.sub.1i,b.sub.2i, . . . ,b.sub.mi }.sup.T,i=1,2, . . . ,n and B.sub.mn ={b.sub.1,b.sub.2, . . . ,b.sub.n }.
Each beamforming matrix for a specific frequency band can be determined independently based on many factors. These include the beam direction angle, feeder array geometry, and the transmitting RF frequency. Additionally, the vectors should be carefully selected such that the beams operating at the same frequency provide enough isolation in case of frequency reuse to avoid excessive co-channel interference, in accordance with frequency planning.
In the preferred embodiment, the matrix processing is conducted at the baseband symbol rate. This significantly reduces the computation load on the digital signal processor hardware compared with the processing at a much higher rate after the pulse-shaping filtering.
The output of the beamforming matrix processing is denoted as β i . This output is coupled to the input of the pulse-shaping filters (405-406) to serve as the input impulse.
The pulse-shaping, lowpass filters (405-406) are the digital FIR filters specified in the F m and g(t) equations discussed subsequently. These filters increase the sampling rate in order to maintain the shape of the waveform and minimize aliasing. The pulse-shaping filters are the same for all feeds.
The embodiment details of FIG. 5 also depend on the digital radio system's RF modulation scheme. A GSM radio (501) ground beamforming network is presented in FIG. 5 for illustration purposes. Other types of radios may also be used in other embodiments. The particular specifications are defined in associated standards and are well known in the art and not discussed here.
The linear pulse-shaping digital filter is defined by: ##EQU1## where B is the 3 dB bandwidth of the filter with impulse response h(t) and T is the duration of one input data bit.
To increase the processing speed to satisfy the real-time requirement, the filters are implemented using fixed-point techniques. The word length depends on the precision requirement of the phase and amplitude of the beamforming signals. The output of the pulse-shaping filtering is still in digital form, although at a higher sample rate than the input.
FIG. 5 illustrates a use of the baseband beamforming network of FIG. 4. The multi-frequency, multi-beamforming network of FIG. 5 is comprised of k channels with each channel having n input signals and m feeds. In this example, k is limited by the RF bandwidth of each RF channel that depends on the particular technology used and the total RF bandwidth that is allocated for the system.
The processing channels for the different frequencies are exactly the same. Therefore, for clarity, the subsequent description is based on only one of the channels.
The GSM radio transmitters (501) use the Gaussian Minimum Shift Keying modulation scheme. The digital symbol rate is 270.833 kbps and the RF channel spacing is 200 kHz. The beam signal from the radio transmitter (501) is input to the baseband beamforming network (400)
The responsibility of the baseband beamforming network (400), including both the ground and space segments, is to precisely rotate the phase and modify the amplitude of the input signals so that they will produce expected beam pattern when they reach the feed elements over the antenna on the satellite. These precise phase relationships between signals must be preserved at the satellite feeds. The baseband beamforming network (400) of FIG. 5 is illustrated and discussed above in FIGS. 4 and 6.
The m feeds from the baseband beamforming network (400) are input to the coherent multiplexer (505). The multiplexer (505) combines all of the feeds into one signal. This multiplexed signal is input to the RF modulator (510) that modulates the signal to the designated feeder link with an appropriate offset frequency, as determined by the modulator's local oscillator (525).
The modulated signals from all of the separate channels are input to the summer (515). The summer (515) adds all of the channels for transmission. The summed signal is input to the power amplifier (520) for adjustment of the transmit power before transmission to the satellite.
The benefits of the present invention are illustrated by the following computational complexity comparison. The number of operations per second of both the prior art beamforming system and the present invention are considered.
For the prior art system, the input radio symbol vector is defined as R n , the baseband symbol rate is r b , the oversampling ratio is n, and the beamforming matrix is B mn . In this case, m is the number of feeds and n is the number of radios (beams). The number of radios is affected by the frequency reuse.
The vector F m represents the output of the beamforming matrix operation. The vectors are coupled to either the multiplexer or the pulse-shaping, lowpass filter bank, depending on the implementation. The beamforming matrix processing is represented as the matrix equation below. The matrix elements b ij are generally of complex values. ##EQU2##
A simple calculation gives the total required complex operations per second, including multiplication and additions, for the prior art beamforming processing as:
r.sub.b ×η×(n×m+n×(m-1)).
For the system of the present invention, the computation requirement becomes:
1/2×r.sub.b ×(n×m+n×(m-1)).
The factor η disappeared due to the beamforming processing being carried out at the baseband symbol rate. The saving factor of 1/2 results from the baseband signal being in real form.
It can be seen that the net savings on a digital signal processor's computational load are a factor of 2η. For η=(4 to 8), the savings is approximately an order of magnitude and is very significant when the system is operating at the high edge of digital signal processing devices. The resulting design of the present invention, therefore, provides a more robust and economic system with less demanding digital signal processor hardware. | A plurality of bit stream formatters formats and codes the digital information signals that are to be transmitted. A symbol generator generates I and Q symbols from the formatted information signals. These symbols are input to the beamforming matrix that is connected directly to the symbol generators. The beamforming matrix generates baseband beam signals from the I and Q symbols. Baseband, pulse-shaping, low-pass filters are connected to the beamforming matrix. The low-pass filters each generate an antenna feed signal from each of the baseband beam signals. | 7 |
BACKGROUND OF THE INVENTION
This invention relates to a device for passing weft yarns to at least one weft insertion means on a weaving machine, which can be operated in order either to bring a weft within the weft feed area of the weft insertion means so that a weft can be inserted, or to hold it out of this feed area to effectuate a weft cancellation.
This device also relates to a weaving machine provided with such a offering device for wefts.
Known weaving machines comprise a mechanism for inserting wefts between warp yarns. Such a mechanism comprises one or more weft insertion means, such as for example rapiers, which can be operated in order in the course of successive weft insertion cycles to bring a respective weft into a shed formed between warp yarns.
In order to be able to weave certain weave constructions or to be able to weave in an efficient manner it is necessary to prevent the insertion of one of more wefts in the course of certain insertion cycles. By means of the above described device this can be effected automatically. The prevention of the insertion of a weft by a weft insertion means is generally referred to by the term “weft cancellation”.
Such offering devices for wefts with which weft cancellations can be effected automatically are generally known.
The known devices comprise weft cutters which are provided in order after each weft insertion to cut off the piece of weft yarn, inserted in the fabric, from the weft yarn fed from the supply package, and in order, after cutting off the piece of weft, to clamp the free extremity of the fed weft. These weft cutters are connected to the weaving batten and therefore move back and forth with every beating-up. The clamped weft is brought below the movement path of a rapier in the course of the return movement of the weaving batten. These devices furthermore also comprise a swivelling arm with a guiding eye for the weft. The swivelling arm is rotatably connected to the frame of the weaving machine and can be operated in order whether or not to bring the weft extending through the guiding eye above the movement path of the rapier.
If a weft has to be inserted the weft cutters are operated in order to cut through and clamp the weft. The clamping means move with the weaving batten and bring the weft under the rapier movement path. The swivelling arm is at that moment rotated to a position in which the guiding eye brings the weft above the movement path of the rapier, so that the part of the weft extending between the clamping means and the guiding eye is within the feed area of the rapier.
If on the other hand a weft cancellation has to be effected the weft cutters are not operated in order to cut through the weft. The weft therefore remains connected to the fell of the fabric and is also not clamped by the clamping means. Because of this the weft is also not carried to below the rapier movement path, with the beating-up movement of the batten. The swivelling arm is also not operated to bring the weft to above this movement path, so that the weft remains outside the feed area of the rapier.
A disadvantage of these known devices is that the swivelling levers and their operation are rather complex and expensive.
SUMMARY OF THE INVENTION
The purpose of this invention is to provide such a device which on the one hand is simpler and cheaper than the known devices, and which on the other hand can nevertheless operate in a very efficient manner and enables a proper and fast operation of the weaving machine, without any reduction of quality for the fabrics.
This objective is achieved by providing a device with the characteristics mentioned in the first paragraph of this specification, which furthermore comprises a yarn carrier which is provided in order to be moved by a weaving machine drive in order to bring a weft within the aforesaid feed area, and which can be operated in order to bring the weft and the carrier into a first and a second mutual position, while the weft in the first mutual position can, and in the second mutual position cannot be carried along by the yarn carrier to the aforesaid feed area.
The movement of the yarn carrier can among others be effected by the weaving batten drive, whereby the yarn carrier is for example attached to a part of the weaving machine moving synchronously with the movements of the weaving batten. The offering of a weft to a weft insertion means therefore no longer requires a separately operable drive mechanism. The expensive and complex swivelling levers are therefore no longer necessary. The performance of a weft cancellation can occur by so altering the mutual position of the weft and the yarn carrier that this weft cannot be carried along by the yarn carrier. This can be effected in a very efficient manner with simple means.
With a weft cancellation the piece of weft that was inserted in the course of the previous insertion cycle is not cut off from the weft supply means, so that this remains connected to the fabric. The weft is not clamped by the moving weft cutters during the beating-up movement and is with use of the device according to this invention furthermore also not carried along by the yarn carrier, so that there is no danger at all that the weft is withdrawn from the fell of the fabric.
This danger would namely exist if the known swivelling levers with guiding eye were just to be replaced by a guiding eye that is permanently attached to the weaving batten. Indeed with a weft cancellation the non-cut-off weft yarn extending through the guiding eye would in the course of the return movement of the weaving batten, as a result of the frictions in the guiding eye, be withdrawn from the fell of the fabric. The quality of the fabric would be reduced because of this. More specifically faults would be discovered in the pile height.
Especially with fast-running weaving machines these frictions would also lead to a non-cut-off weft no longer being able to be held sufficiently under tension. With an offering following thereafter of this weft to a weft insertion means, the chance would be inadmissibly great that the weft is not properly stretched, and consequently is not carried along by the weft insertion means. The quality of the fabric would therefore also be reduced through so-called weft faults. This would especially occur with the weaving of thicker weft yarns, such as e.g. jute and polypropylene yarns.
With use of the device according to this invention the weft is in the course of a weft cancellation not subject to frictions. The wefts can consequently be held sufficiently under tension in order to prevent weft faults, and are not withdrawn from the fell of the fabric. The quality of the fabric therefore remains guaranteed, even when weaving with fast-running weaving machines or with interweaving thicker weft yarns.
The device according to this invention is preferably provided with a movable pusher element that can be operated in order to bring a weft into a first and into a second position in relation to the yarn carrier, whereby this can, respectively cannot be carried along by the yarn carrier.
Such a pusher element can be moved by means of a very simple and inexpensive actuator, such as for example an electromagnet with plunger or a pneumatic cylinder. A vertical movement over a rather small height can moreover already be sufficient.
The device according to the invention in a very simple and efficiently operating embodiment comprises a yarn carrier which is connected to the weaving batten of the weaving machine. No expensive and complex drive device is necessary, while the yarn carrier is nevertheless driven in a very operationally safe manner, synchronous with the beating-up movements, in order to bring wefts at the correct moment within the feed area of a weft insertion means.
With another preferred embodiment of the device according to this invention the pusher element is connected to the frame of the weaving machine.
The device according to this invention can also be provided with a yarn carrier which can be operated in order to take a first or a second position, whereby this can, respectively cannot, carry along a weft.
The yarn carrier preferably has an upper surface inclined upward from a front rim, provided with a catch edge behind which a weft can hook on in order to be carried along to the aforesaid feed area.
The front rim and the upwardly inclined upper surface are particularly well suited for as it were catching a weft in the course of the movement of the yarn carrier.
In its most preferred embodiment the yarn carrier comprises a carrier edge which is formed by a transverse rim of the upper surface, while the yarn carrier can be placed in a first position whereby the transverse rim is directed upward in order to enable a weft extending above the yarn carrier to hook on behind the carrier edge, and can be placed in a second position whereby the transverse rim is directed downward in order to prevent a weft thread extending above the yarn carrier from hooking on behind this carrier edge.
The yarn carrier can for example be placed in its first and its second position by a rotation thereof through a small angle. This can occur with very simple drive means, such as for example a pneumatic cylinder or a rotary motor.
The yarn carrier is preferably implemented knife-shaped with an upwardly curved upper surface. This shape is ideal for picking up a weft.
In another embodiment this device comprises a cutting and clamping device, which can be operated in order to cut through and to clamp a weft.
The device can furthermore also be provided in order in successive operating cycles to offer two or more weft threads to respective weft insertion means, while the device comprises a yarn carrier for each weft which is provided in order to be moved by a weaving machine drive in order to bring a weft within the aforesaidfeed area, while the device can be operated in order to bring the weft and the yarn carrier into a first and a second mutual position, and while the weft in the first mutual position can, and in the second mutual position cannot be carried along by the yarn carrier to the aforesaid feed area.
In that which follows two possible embodiments of an offering device for wefts according to this invention are described in detail. This specification only serves to explain further the characteristics and the operation of a device according to this invention, and may therefore not be considered as a restriction on the protection claimed for this invention in the claims of this patent application.
In this specification reference is made by means of reference numbers to the figures attached hereto. These figures are perspective views of a triple offering device for wefts on a three-rapier weaving machine, whereby the middle offering device in FIGS. 1 through 8 is a first embodiment, and in FIGS. 9 through 16 is a second embodiment of a device according to this invention. These figures show for each embodiment four different positions in the course of the operation of the device, whereby two successive figures in each case show the same position from a different direction of view. Of the three-rapier weaving machine in each case only the three rapiers and a number of parts are partially represented.
BRIEF DESCRIPTION OF THE DRAWINGS
Of FIGS. 1 through 8, in which the first embodiment of the middle offering device according to this invention has been represented,
FIGS. 1 and 2 show a position in which the device is ready to carry along all wefts to the rapiers,
FIGS. 3 and 4 show a position in which the device has brought the wefts within the feed area of a respective rapier,
FIGS. 5 and 6 show a position in which the device is ready to carry along the top and bottom weft to a rapier, and to cancel the insertion of the middle weft,
FIGS. 7 and 8 show a position in the course of the implementation of the weft cancellation of the middle weft.
Of FIGS. 9 through 16, in which the second embodiment of the middle offering device according to this invention has been represented,
FIGS. 9 and 10 show a position in which the device is ready to carry along all wefts,
FIGS. 11 and 12 show a position in which the device has brought the wefts within the feed area of a respective rapier,
FIGS. 13 and 14 show a position in which the device is ready to carry along the top and bottom weft, and to cancel the insertion of the middle weft,
FIGS. 15 and 16 show a position in the course of the implementation of the weft cancellation of the middle weft.
DETAILED DESCRIPTION
The offering device for wefts represented in the figures is disposed on a face-to-face weaving machine with three rapier systems operating one above the other for the insertion of three wefts ( 1 ), ( 2 ), ( 3 ) between warp yarns ( 4 ) per weft insertion cycle. Each rapier system has an insert rapier ( 5 ), ( 6 ), ( 7 ) which is driven to move in and out of a shed in the course of each insertion cycle in order to bring a carried along weft ( 1 ), ( 2 ), ( 3 ) to approximately halfway in this shed, and a gripper rapier (not represented in the figures) which is moved in and out of this shed from the other shed side in order to receive the weft thread in the shed from the insert rapier and pull it through to the other side of the shed.
The weaving machine is provided with a device for automatically offering respective weft threads ( 1 ), ( 2 ), ( 3 ) to the insert rapiers ( 5 ), ( 6 ), ( 7 ) in the course of each insertion cycle. These wefts are fed from supply packages not represented in the figures. This device consists of a top ( 8 ), a middle ( 9 ) and a bottom offering device ( 10 ), which are provided in order to work together respectively with the top ( 5 ), the middle ( 6 ) and the bottom insert rapier ( 7 ). The top ( 8 ) and the bottom device ( 10 ) are known offering devices which are not provided for performing a weft cancellation. The middle device ( 9 ) on the other hand is provided for effecting a weft cancellation and is implemented according to this invention.
The top ( 8 ) and the bottom offering device ( 10 ) comprise weft cutters ( 12 ), ( 14 ) disposed on the weaving batten ( 11 ) which are provided in order to cut through and to clamp a weft thread ( 1 ), ( 3 ). These offering devices ( 8 ), ( 10 ) also comprise a guiding eye ( 15 ), ( 16 ) for a weft ( 1 ), ( 3 ), disposed on the weaving batten ( 11 ).
The weaving batten ( 11 ) is driven in order in the course of each weft insertion cycle to move back and forth in order to perform the so-called beating-up movement whereby with the weaving reed ( 17 ) the just inserted weft thread is pushed against the fell of the fabric of the already formed fabric ( 18 ). During this beating-up movement the weft cutters ( 12 ), ( 14 ) of the top and the bottom offering device ( 8 ), ( 10 ) are in each case operated in order to cut off the just inserted piece of weft ( 1 ), ( 3 ) (so that it is no longer connected to the package), and in order to clamp the free extremity of the weft thread fed from the bobbin. Through the return movement of the weaving batten ( 11 ) the top and the bottom offering device ( 8 ), ( 10 ) in each case take a respective clamped weft ( 1 ), ( 3 ) along to a position whereby the part of these wefts ( 1 ), ( 3 ) extending between the clamping means and the guiding eye ( 15 ), ( 16 ) traverses the movement path of a rapier ( 5 ), ( 7 ) and can therefore be brought by the rapier into a shed between the warp yarns ( 4 ).
The middle passing device ( 9 ) according to this invention also comprises weft cutters ( 13 ) provided on the weaving batten ( 11 ), but in place of a guiding eye a carrier spoon ( 19 ) is provided on the weaving batten. This carrier spoon ( 19 ) is an elongated element with a limited thickness and a width which gradually decreases from a rear transverse rim ( 20 ) in order to end almost pointed in front, and is curved downward from the aforesaid rear rim ( 20 ) so that the carrier spoon ( 19 ) has a curved upper surface.
With the first embodiment according to FIGS. 1 through 8 this carrier spoon ( 19 ) is secured in a fixed position on the weaving batten ( 11 ) and the device has a pusher element ( 22 ), which can be moved up and down by means of a compressed air cylinder ( 21 ), with which the middle weft ( 2 ) can be pushed upward. This pusher element ( 22 ) has approximately the same form as the yarn carrier.
If the position of the middle weft ( 2 ) is not influenced by the pusher element ( 22 ) this weft is in a position whereby it can be picked up by the carrier spoon ( 19 ) in the course of the beating-up movement of the weaving batten. This weft remains hooked behind the rear transverse rim ( 20 ) of the carrier spoon ( 19 ) and is because of this carried along in the course of the return movement of the weaving batten ( 11 ) to above the movement path of the middle rapier ( 6 ). The weft cutters of the middle offering device ( 9 ) are operated in order to cut through and to clamp the weft ( 2 ), so that the clamping means bring the weft ( 2 ) below the aforesaid movement path. Because of this the part of the weft extending between these clamping means and the carrier spoon ( 19 ) traverses the movement path of the rapier ( 6 ), so that the weft ( 2 ) can be carried along by this rapier ( 6 ).
If the middle weft ( 2 ) is pushed upward by the pusher element ( 22 ), the weft ( 2 ) extends higher than the upper surface of the carrier spoon ( 19 ), so that this weft ( 2 ) does not remain hooked behind the rear rim ( 20 ) and can therefore not be carried along by the carrier spoon ( 19 ). The weft cutters ( 13 ) are therefore not operated for cutting through and clamping the weft thread ( 2 ). The fed weft ( 2 ) therefore remains attached to the yarn part inserted in the fabric ( 18 ). Since this weft ( 2 ) is not carried along, neither by the carrier spoon ( 19 ) nor by the clamping means of the weft cutters ( 13 ) this weft remains in the same position in the course of the return movement of the weaving batten ( 11 ). No friction at all is exerted on the weft ( 2 ), so that this yarn can be maintained sufficiently under tension and is not withdrawn from the fell of the fabric in the course of the return movement of the weaving batten ( 11 ).
In FIGS. 1 and 2 the offering device is represented in the situation whereby the weaving batten ( 11 ) is in the beating-up position. The weft cutters ( 12 ), ( 13 ), ( 14 ) and the guiding eyes ( 15 ), ( 16 ) are therefore in their most forward position. The parts of the three wefts ( 1 ), ( 2 ), ( 3 ) inserted in the course of the previous weft insertion cycle are not cut off. The pusher element ( 22 ) is in its lowest position and therefore does not push the middle weft ( 2 ) upward. In this situation (see FIGS. 3 and 4 ), in addition to the top ( 1 ) and the bottom weft ( 3 ), the middle weft ( 2 ) will also be carried along.
In FIGS. 3 and 4 the device can be seen in the situation following thereafter whereby the three wefts ( 1 ), ( 2 ), ( 3 ) are cut through and clamped by their weft cutters ( 12 ), ( 13 ), ( 14 ) and are carried along by their respective offering devices ( 8 ), ( 9 ), ( 10 ) to within the feed area of the rapiers ( 5 ), ( 6 ), ( 7 ). The top ( 1 ) and the bottom weft thread ( 3 ) are carried along by the clamping means and the guiding eyes ( 15 ), ( 16 ) on the weaving batten ( 11 ), while the middle weft ( 2 ) is also carried along by the clamping means of the middle weft cutters ( 13 ), and furthermore in the course of the return movement of the weaving batten ( 11 ) has remained hooked behind the transverse rim ( 20 ) of the carrier spoon ( 19 ).
The situation in FIGS. 5 and 6 differs from the situation in FIGS. 1 and 2 only because of the fact that the pusher element ( 22 ) is now in its highest position and pushes the middle weft ( 2 ) upward. In this situation (see FIGS. 7 and 8) the middle weft ( 2 ) will not be able to hook on behind the transverse rim ( 20 ) of the carrier spoon ( 19 ) and will therefore not be carried along by this carrier spoon ( 19 ) in the course of the return movement of the weaving batten ( 11 ). The carrier spoon ( 19 ) moves through below the weft ( 2 ).
In FIGS. 7 and 8 the device can be seen in the situation following thereafter whereby the top ( 1 ) and the bottom weft ( 3 ) are cut through and clamped by their weft cutters ( 12 ), ( 14 ) and are brought by the respective clamping means and guiding eyes ( 15 ), ( 16 ) within the carrier range of the rapiers ( 5 ), ( 7 ), while the middle weft ( 2 ) is not cut through and clamped by its weft shears ( 13 ) and is neither carried along by the clamping means, nor by the carrier spoon ( 19 ).
With the second embodiment according to FIGS. 9 through 16 no pusher element ( 22 ) is provided and the carrier spoon ( 19 ) is secured to a rotatable spindle ( 23 ) extending in the longitudinal direction of the carrier spoon ( 19 ). The carrier spoon ( 19 ) has a part extending laterally in relation to the spindle in the direction of the weft cutters ( 13 ). Through rotation of the spindle ( 23 ) the carrier spoon ( 19 ) can be placed in a first position whereby the laterally extending part of the transverse rim ( 20 ) is directed upward from the spindle, and can be placed in a second position whereby the aforesaid extending part of the transverse rim ( 20 ) is directed downward.
If the carrier spoon ( 19 ) is placed in the first position (with upwardly directed transverse rim) a weft ( 2 ) extending above the carrier spoon ( 19 ) will be carried along by the transverse rim ( 20 ) if the carrier spoon ( 19 ) moves backward. If the carrier spoon ( 19 ) is in the second position (with downwardly directed transverse rim) a weft ( 2 ) extending above the carrier spoon ( 19 ) will not be carried along in the course of the return movement of the weaving batten ( 11 ). In this manner by influencing the position of the carrier spoon ( 19 ) it can be determined whether or not a weft ( 2 ) is carried along by this carrier spoon ( 19 ).
The rotation of the spindle ( 23 ) in order to control the position of the carrier spoon ( 19 ) occurs by means of a rotary motor or a pneumatic cylinder (not represented in the figures).
In FIGS. 9 and 10 the offering device is represented in the situation whereby the weaving batten ( 11 ) is in the beating-up position. The weft cutters ( 12 ), ( 13 ), ( 14 ) and the guiding eyes ( 15 ), ( 16 ) are therefore in their most forward position. The parts of the three wefts ( 1 ), ( 2 ), ( 3 ) inserted in the course of the previous weft insertion cycle are not cut off. The carrier spoon ( 19 ) is rotated into the first position with upwardly directed transverse rim ( 20 ). In this situation (see FIGS. 11 and 12 ), in addition to the top ( 1 ) and the bottom weft ( 3 ), the middle weft ( 2 ) will also be carried along.
In FIGS. 11 and 12 the device can be seen in the situation following thereafter whereby the three wefts ( 1 ), ( 2 ), ( 3 ) are cut through and clamped by their weft cutters ( 12 ), ( 13 ), ( 14 ) and are carried along by their respective offering devices ( 8 ), ( 9 ), ( 10 ) to within the carrier range of the rapiers ( 5 ), ( 6 ), ( 7 ). The top ( 1 ) and the bottom weft ( 3 ) are carried along by the clamping means and the guiding eyes ( 15 ), ( 16 ) on the weaving batten ( 11 ), while the middle weft ( 2 ) is carried along by the clamping means of the middle weft cutters ( 13 ) and furthermore in the course of the return movement of the weaving batten ( 11 ) has remained hooked behind the transverse rim ( 20 ) of the carrier spoon ( 19 ).
The situation in FIGS. 13 and 14 differs from the situation in FIGS. 9 and 10 only because of the fact that the carrier spoon is now rotated into its second position with downwardly directed transverse rim ( 20 ). In this situation (see FIGS. 15 and 16) the middle weft ( 2 ) will not be able to hook on behind the transverse rim ( 20 ) of the carrier spoon ( 19 ) and will therefore not be carried along in the course of the return movement of the weaving batten ( 11 ) .
In FIGS. 15 and 16 the device can be seen in the situation following thereafter whereby the top ( 1 ) and the bottom weft ( 3 ) are cut through and clamped by their weft shears ( 12 ), ( 14 ) and are brought by the respective clamping means and guiding eyes ( 15 ), ( 16 ) within the carrier range of the rapiers ( 5 ), ( 7 ), while the middle weft ( 2 ) is not cut through and clamped by its weft shears ( 13 ) and is neither carried along by the clamping means, nor by the carrier spoon ( 19 ).
Such a triple offering device can also be implemented with two or three offering devices which are suitable for weft cancellation and are implemented according to this invention.
It is obvious that several offering devices with two offering devices or with more than three offering devices, of which at least one is implemented according to this invention, and weaving machines provided with such a multiple offering device, also fall within the scope of this patent protection. | Device for weft cancellation on a weaving machine offers wefts ( 1 ), ( 2 ), ( 3 ) to at least one weft insertion ( 5 ), ( 6 ), ( 7 ) on a weaving machine, which can be operated in order either to bring a weft within the feed area of a weft insertion or to hold it out of this feed area, to effect a weft cancellation. The device has a yarn carrier ( 19 ) which can be moved by a weaving machine drive in order to bring a weft ( 2 ) within the aforementioned feed area. The device can be operated in order to bring the yarn carrier ( 19 ) and a weft ( 2 ) into a first and a second mutual position, in which this weft ( 2 ) can or cannot be carried along by the yarn carrier ( 19 ) within the aforementioned feed area. A first embodiment comprises a movable pusher element ( 22 ) that can be operated in order to bring a weft ( 2 ) into a first and into a second position in relation to the yarn carrier ( 19 ). In a second embodiment the yarn carrier ( 19 ) can itself be brought into two different positions. | 3 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is related to U.S. patent application Ser. No. 13/449,888, filed on Apr. 18, 2012, issued Jun. 10, 2014 as U.S. Pat. No. 8,747,617, which is a continuation-in-part of U.S. patent application Ser. No. 11/854,044, filed Sep. 12, 2007, issued May 8, 2012 as U.S. Pat. No. 8,172,983. This application is also related to U.S. patent application Ser. No. 12/975,596, filed Dec. 22, 2012, issued Feb. 26, 2013 as U.S. Pat. No. 8,382,950, which is a continuation-in-part of U.S. patent application Ser. No. 11/854,044, issued as U.S. Pat. No. 8,172,983, previously discussed. Each aforementioned disclosure is incorporated herein by reference in its entirety.
STATEMENT REGARDING FEDERALLY SPONSORED RESEARCH OR DEVELOPMENT
Not Applicable.
BACKGROUND OF THE INVENTION
This invention relates to a method of increasing sheet wet web strength, increasing sheet wet strength and enhancing filler retention in a papermaking process. Typically in a papermaking process chemicals are added in the wet end to assist in the dewatering of the slurry, increasing retention and improving wet or dry sheet strength. The wet end of the papermaking process refers to the stage in the papermaking process where the fiber is dispersed in the water in the slurry form. The fiber-water slurry then go through drainage and dewatering process to form a wet web. The solid content after this wet formation process is about 50%. The wet web is further dried and forms a dry sheet of paper mat. Paper mat comprises water and solids and is commonly 4 to 8% water. The solid portion of the paper mat includes fibers (typically cellulose based fibers) and can also include filler.
Fillers are mineral particles that are added to paper mat during the papermaking process to enhance the resulting paper's opacity and light reflecting properties. Some examples of fillers are described in U.S. Pat. Nos. 5,458,679, 5,104,487, 7,211,608, 8,088,250, and European Patent Specification 0 470 871 B1. Fillers include inorganic and organic particle or pigments used to increase the opacity or brightness, reduce the porosity, or reduce the cost of the paper or paperboard sheet. Some examples of fillers include one or more of: kaolin clay, talc, titanium dioxide, alumina trihydrate, barium sulfate, magnesium hydroxide, pigments such as calcium carbonate, and the like.
Calcium carbonate filler comes in two forms, GCC (ground calcium carbonate) and PCC (precipitated calcium carbonate). GCC is naturally occurring calcium carbonate rock and PCC is synthetically produced calcium carbonate. Because it has a greater specific surface area, PCC has greater light scattering abilities and provides better optical properties to the resulting paper. For the same reason however, PCC filled paper mat produces paper which is weaker than GCC filled paper in dry strength, wet strength and wet web strength.
Filler is generally much smaller than fiber, therefore, filler has much larger specific surface area than fiber. One of the challenges people found to increase filler content in the sheet is that high filler content decreases the efficiency of wet end chemicals, such as dewatering aids, wet web strength aids and wet strength aids. This invention is to provide novel filler pretreatment, so that it reduced the adsorption of wet end chemicals onto filler surface, therefore, increased the efficiency of wet end chemicals such as dewatering aids, wet web strength aids and wet strength aids.
Paper wet web strength is very critical for paper producers because increased paper wet web strength would increase machine runnability and reduce sheet breaks and machine down time. Paper wet web strength is a function of the number and the strength of the bonds formed between interweaved fibers of the paper mat. Filler particles with greater surface area are more likely to become engaged to those fibers and interfere with the number and strength of those bonds. Because of its greater surface area, PCC filler interferes with those bonds more than GCC.
Paper dewatering efficiency is also very critical for paper producers because decreased dewatering efficiency in wet web would increase steam demand for drying operation, reduce machine speed and production efficiency. Dewatering aids are widely used to improve dewatering efficiency for reducing energy consumption, increasing machine speed and production efficiency.
Thus there is a clear need for and utility in an improved method of and composition for increasing paper strength in the wet end of a papermaking process. The art described in this section is not intended to constitute an admission that any patent, publication or other information referred to herein is “prior art” with respect to this invention, unless specifically designated as such. In addition, this section should not be construed to mean that a search has been made or that no other pertinent information as defined in 37 C.F.R. §1.56(a) exists.
BRIEF SUMMARY OF THE INVENTION
At least one embodiment of the invention is directed towards a method of papermaking comprising filler. The method comprises the steps of: providing filler particles and cellulose fiber stock, treating either the filler particles or the cellulose fiber stock with a composition comprising at least one natural gum, treating the cellulose fiber stock with a wet web strength additive, combining the filler particles and cellulose fiber stock, and forming a paper mat from the combination. The cellulose fiber stock comprises a plurality of cellulose fibers and water. The resulting paper has greater strength than the sum of the strength improvements that the natural gum composition and the wet web strength additive impart alone.
The natural gum composition may be added to the filler particles before they are added to the cellulose fiber stock. The natural gum composition may be added to the cellulose fiber stock. The wet web strength additive may comprise GPAM. The method may further comprise the step of adding a drainage aid to the cellulose fiber is stock. At least some of the filler particles may be calcium carbonate in one form selected from the list consisting of undispersed calcium carbonate, dispersed slurry calcium carbonate, chalk, PCC, GCC and any combination thereof. At least a portion of the calcium carbonate may be in a dispersed slurry calcium carbonate form, the dispersed slurry calcium carbonate further comprising at least one item selected from: polyacrylic acid polymer dispersants, sodium polyphosphate dispersants, Kaolin clay slurry, and any combination thereof. The wet web strength additive may be a coagulant selected from the list consisting of: inorganic coagulants, organic coagulants, condensation polymerization coagulants, and any combination thereof.
DETAILED DESCRIPTION OF THE INVENTION
The following definitions are provided to determine how terms used in this application, and in particular how the claims, are to be construed. The organization of the definitions is for convenience only and is not intended to limit any of the definitions to any particular category.
“AcAm” means a copolymer constructed out of polymerized acrylic acid monomeric units and polymerized acrylamide monomeric units and may or may not include other monomeric units.
“Coagulant” means a composition of matter having a higher charge density and lower molecular weight than a flocculant, which when added to a liquid containing finely divided suspended particles, destabilizes and aggregates the solids through the mechanism of ionic charge neutralization.
“DADMAC” means monomeric units of diallyldimethylammonium chloride, DADMAC can be present in a homopolymer or in a copolymer comprising other monomeric units.
“Flocculant” means a composition of matter having a low charge density and a high molecular weight (in excess of 1,000,000) which when added to a liquid containing finely divided suspended particles, destabilizes and aggregates the solids through the mechanism of interparticle bridging.
“Flocculating Agent” means a composition of matter which when added to a liquid destabilizes, and aggregates colloidal and finely divided suspended particles in the liquid, flocculants and coagulants can be flocculating agents.
“GCC” means ground calcium carbonate filler particles, which are manufactured by grinding naturally occurring calcium carbonate rock.
“GPAM” means glyoxalated polyacrylamide, which is a polymer made from polymerized acrylamide monomers (which may or may not be a copolymer comprising one or more other monomers as well) and in which acrylamide polymeric units have been reacted with glyoxal groups, representative examples of GPAM are described in US Published Patent Application 2009/0165978.
“Natural Gum” means a polysaccharide characterized as being originally of natural origin and which when placed in a solution imposes a large viscosity increase in said solution even when in a small concentration, natural gum includes a number of plant resins and includes but is not limited to seaweed polyelectrolytes such as agar, alginic acid, sodium alginate, carrageenan, botanical polyelectrolytes such as gum arabic from acacia tree sap, gum ghatti from anogeissus tree sap, gum tragacanth from astragalus shrub sap, karaya gum from anogeissus tree sap, gum tragacanth from astragalus shrub sap, kararya gum from sterculia tree sap, uncharged botanicals such as guar gum from guar beans, locust bean gum from carob tree seeds, beta-glucan from oat and barley bran, chicle gum from chicle trees, dammar gum from dipterocarpaceae tree sap, glucommannan from koniac plants, mastic gum from mastic trees, psyllium seed husks from plantago plants, spruce gum from spruce trees, tara gum from tara tree seeds, and bacterial fermentation products such as gellan gum and xantham gum, “natural gum” also includes natural gum derivatives.
“Natural Gum Derivative” means a natural gum polysaccharide which has undergone some measure of chemical substitution of one or more of the subgroups (e.g. carboxymethyl, hydroxypropyl) in one, some or all of the monomer units in the polysaccharide backbone, the substitute constituents typically comprise one or more of sulfate, carboxylic acid (found in carragenan, alginate, pectin), carboxylic ester, pyruvic acid (found in pectin, xanthan gum, zooglan, and methylan), carboxymethyl, hydroxypropyl, methyl, methylethyl, hydroxyethyl, hydroxyethylmethyl and the like.
“PCC” means precipitated calcium carbonate filler particles, which are synthetically produced.
“Polysaccharide” means a polymeric carbohydrate having a plurality of repeating units comprised of simple sugars, the C—O—C linkage formed between two such joined simple sugar units in a polysaccharide chain is called a glycosidic linkage, and continued condensation of monosaccharide units will result in polysaccharides, common polysaccharides are amylose and cellulose, both made up of glucose monomers, polysaccharides can have a straight chain or branched polymer backbone including one or more sugar monomers, common sugar monomers in polysaccharides include glucose, galactose, arabinose, mannose, fructose, rahmnose, and xylose.
“Preflocculation” means the modification of filler particles through treatment with coagulants and/or flocculants prior to their addition to the paper stock, in such an amount that actual flocculation does not occur, preflocculation is not conducted in the presence of the paper stock, typically after preflocculation, more of the same or a different kind of coagulant and/or flocculant is subsequently added to the preflocculated filler particles to initiate actual flocculation.
In the event that the above definitions or a description stated elsewhere in this application is inconsistent with a meaning (explicit or implicit) which is commonly used, in a dictionary, or stated in a source incorporated by reference into this application, the application and the claim terms in particular are understood to be construed according to the definition or description in this application, and not according to the common definition, dictionary definition, or the definition that was incorporated by reference, In light of the above, in the event that a term can only be understood if it is construed by a dictionary, if the term is defined by the Kirk - Othmer Encyclopedia of Chemical Technology, 5th Edition, (2005), (Published by Wiley, John & Sons, Inc.) this definition shall control how the term is to be defined in the claims.
In at least one embodiment of the invention is a method of making paper Which comprises filler. In at least one embodiment of the invention the method of papermaking comprises the steps of adding at least one natural gum to filler particles and/or to paper mat containing filler particles. In at least one embodiment also added to the filler particles and/or to paper mat is a wet web strength additive or drainage aid or wet strength aid to the paper mat. In at least one embodiment the wet web strength additive comprises GPAM.
The combination of a wet web strength additive with a natural gum results in a surprising synergy which increases the strength of the resulting paper by more than the sum of either of the two added alone. This inventive combination also solves some of the problems inherent in using wet web strength additives in papermaking as well as in using natural gums. It has been known for some time that adding wet web strength additives or drainage aid or wet strength aid to paper mat increases the wet web strength of the resulting paper or enhances drainage or improves machine speed and runnability or enhance sheet wet strength. Some examples of wet strength aids, wet web strength additives and drainage aids are described in U.S. Pat. Nos. 7,125,469, 7,615,135 and 7,641,776.
Unfortunately it is not practical to add large amounts of wet strength aids or wet web strength additives or drainage aids to compensate for the weakness due to large amounts of filler in paper mat. One reason is because those additives are expensive and using large amounts of additives would result in production costs that are commercially non-viable. In addition, adding too much additive negatively affects the process of papermaking and inhibits the operability of various forms of papermaking equipment. Furthermore cellulose fibers can only adsorb a limited amount of wet strength aid or wet web strength additive or drainage aid. This imposes a limit on how much additive can be used. One reason why this is so is because wet strength aid or wet web strength additive or drainage aid tend to neutralize the anionic fiber/filler charges and when these charges are neutralized further adsorption of those additives is inhibited.
Adding filler to the paper mat also reduces the effectiveness of the wet strength aid or wet web strength additive or drainage aid. Those additives have a tendency to coat the filler particles. The more filler particles present, the more additive coats the filler particles, and therefore there is less wet strength aid or wet web strength additive or drainage available to bind the cellulose fibers together. Because there is a maximum amount of wet strength aid or wet web strength additive or drainage that can be added, more filler has always meant less effective strength additive. This effect is more acute with PCC than GCC because PCC's higher surface area becomes more coated with the additives than GCC.
U.S. Pat. No. 5,458,679 describes treating filler particles with polysaccharides. However it fails to describe how using the polysaccharides to alter the viscosity of the filler particles would enhance the strength properties of the resulting paper. Details regarding the viscosity imparting effects of natural gums can be found in the scientific article: Alternan and highly branched limit dextrans: Low - viscosity polysaccharides as potential new food ingredients , by Gregory L. Cote et al., In: Spanier A. M. et al. (ed) Chemistry of Novel Foods, Carol Stream, Ill.: Allured Publishing Corp, pgs, 95-110 (1997) which discusses such natural gums as alternan and gum arabic (in particular FIGS. 2 and 3). In at least one embodiment the viscosity of the filler containing composition (which will later be added to paper mat) is increased by between 10-100% by the presence of natural gums with the filler particles.
In at least one embodiment of the invention at least some of the filler particles are pre-treated with a pre-treating composition comprising at least one natural gum to at least partially prevent the adherence of wet strength aid or wet web strength additive or drainage aid to the filler particles. The pre-treatment may involve entirely coating some or all of one or more filler particles with the natural gum. In the alternative, the pre-treatment contemplates applying the natural gum to only a portion of one or more of the filler particles, or completely coating some filler particles and applying the natural gum to only a portion of some other particles. The natural gum may be applied to the filler particles, before, after, or simultaneous to one or more steps of the other filler pre-treatment(s).
In at least one embodiment, in addition to contacting the filler particles with natural gums, the filler particles are also treated according at least one of the methods and compositions described in U.S. patent application Ser. No. 12/323,976 titled METHOD OF INCREASING FILLER CONTENT IN PAPERMAKING. In at least one embodiment, the treating composition of matter is any one of or combination of the compositions of matter described in U.S. Pat. No. 6,592,718. In particular, any of the AcAm/DADMAC copolymer compositions described in detail therein are suitable as the treating composition of matter. An example of an AcAm/DADMAC copolymer composition is product# Nalco-4690 from Nalco Company of Naperville, Ill. (hereinafter referred to as 4690).
The treating composition of matter can be a coagulant. The coagulants encompassed in this invention are well known and commercially available. They may be inorganic or organic. Representative inorganic coagulants include alum, sodium aluminate, polyaluminum chlorides or PACs (which are also known as aluminum chlorohydroxide, aluminum hydroxide chloride, and polyaluminum hydroxychloride), sulfated polyaluminum chlorides, polyaluminum silica sulfate, ferric sulfate, ferric chloride, and the like and blends thereof.
Some organic coagulants suitable as a treating composition of matter are formed by condensation polymerization. Examples of polymers of this type include epichlorohydrin-dimethylamine (EPI-DMA), and EPI-DMA ammonia crosslinked polymers.
Additional coagulants suitable as a treating composition of matter include polymers of ethylene dichloride and ammonia, or ethylene dichloride and dimethylamine, with or without the addition of ammonia, condensation polymers of multifunctional amines such as diethylenetriamine, tetraethylenepentamine, hexamethylenediamine and the like with ethylenedichloride and polymers made by condensation reactions such as melamine formaldehyde resins.
Additional coagulants suitable as a treating composition of matter include cationically charged vinyl addition polymers such as polymers, copolymers, and terpolymers of (meth)acrylamide, diallyl-N,N-disubstituted ammonium halide, dimethylaminoethyl methacrylate and its quaternary ammonium salts, dimethylaminoethyl acrylate and its quaternary ammonium salts, methacrylamidopropyltrimethylammonium chloride, diallylmethyl(beta-propionamido)ammonium chloride, (beta-methacryloyloxyethyl)trimethyl ammonium methylsulfate, quaternized polyvinyllactam, vinylamine, and acrylamide or methacrylamide that has been reacted to produce the Mannich or quaternary Mannich derivatives. Preferable quaternary ammonium salts may be produced using methyl chloride, dimethyl sulfate, or benzyl chloride. The terpolymers may include anionic monomers such as acrylic acid or 2-acrylamido 2-methylpropane sulfonic acid as long as the overall charge on the polymer is cationic. The molecular weights of these polymers, both vinyl addition and condensation, range from as low as several hundred to as high as several million. Preferably, the molecular weight range should be from about 20,000 to about 1,000,000. In at least one embodiment, the pre-treatment is preformed by a combination of one, some, or all of any of the compositions of matter described as suitable compositions of matter for pre-treating the filler particles.
While pre-treating filler particles is known in the art, prior art methods of pre-treating filler particles are not directed towards affecting the adhesion of the wet strength aid or wet web strength additive or drainage aid to the filler particles. In fact, many prior art pre-treatments increase the adhesion of the strength additive to the filler particles. For example, U.S. Pat. No. 7,211,608 describes a method of pre-treating filler particles with hydrophobic polymers. This pre-treatment however does nothing to the adhesion between the strength additive and the filler particles and merely repels water to counterbalance an excess of water absorbed by the strength additive. In contrast, the invention decreases the interactions between the wet strength aid or wet web strength additive or drainage aid and the filler particles and results in an unexpectedly huge increase in paper strength, sheet dewatering and machine runability.
In at least one embodiment, in addition to contacting the filler particles with natural gums, the filler particles are also preflocculated according at least one of the utilizing the methods and compositions described in U.S. Pat. No. 8,172,983. In at least one embodiment the method of preparing a stable dispersion of flocculated filler particles having a specific particle size distribution for use in papermaking processes comprises the steps of a) providing an aqueous dispersion of filler particles; b) adding at least one natural gum to the dispersion, c) adding a first flocculating agent to the dispersion in an amount sufficient to mix uniformly in the dispersion without causing significant flocculation of the filler particles; d) adding a second flocculating agent to the dispersion in an amount sufficient to initiate flocculation of the filler particles in the presence of the first flocculating agent; and e) optionally shearing the flocculated dispersion to provide a dispersion of filler flocs having the desired particle size.
At least some of the fillers encompassed by this invention are well known and commercially available. They include any inorganic or organic particle or pigment used to increase the opacity or brightness, reduce the porosity, or reduce the cost of the paper or paperboard sheet. The most common fillers are calcium carbonate and clay. However, talc, titanium dioxide, alumina trihydrate, barium sulfate, and magnesium hydroxide are also suitable fillers. Calcium carbonate includes ground calcium carbonate (GCC) in a dry or dispersed slurry form, chalk, precipitated calcium carbonate (PCC) of any morphology, and precipitated calcium carbonate in a dispersed slurry form. The dispersed slurry forms of GCC or PCC are typically produced using polyacrylic acid polymer dispersants or sodium polyphosphate dispersants. Each of these dispersants imparts a significant anionic charge to the calcium carbonate particles. Kaolin clay slurries also are dispersed using polyacrylic acid polymers or sodium polyphosphate.
In at least one embodiment, the wet strength aids, wet web strength additives, dry strength additives or drainage aids encompassed by the invention include any one of the compositions of matter described in U.S. Pat. No. 4,605,702 and US Patent Application 2005/0161181 A1 and in particular the various glyoxylated Acrylamide/DADMAC copolymer compositions described therein. An example of a glyoxylated Acrylamide/DADMAC copolymer composition is product# Nalco 63700 (made by Nalco Company, Naperville, Ill.). Another example of is amine-containing polymers including allylamine/acrylamide copolymers and polyvinylamines; one more example is Polyamide-Polyamine-Epichlorohydrin (PAE)
In at least one embodiment, the fillers used are PCC, GCC, and/or kaolin clay. In at least one embodiment, the fillers used are PCC, GCC, and/or kaolin clay with polyacrylic acid polymer dispersants or their blends. The ratio of wet strength additive or wet web strength aid or drainage additive relative to solid paper mat can be 3 kg of additive per ton of paper mat.
In at least one embodiment the method of making paper products from pulp comprises the steps of forming an aqueous cellulosic papermaking furnish, adding an aqueous dispersion of filler slurry combined with the addition of natural gums and wet web strength agent, wet strength agent dry strength agent or draining aids to the furnish, draining the furnish to form a sheet and drying the sheet. The steps of forming the papermaking furnish, draining and drying may be carried out in any conventional manner generally known to those skilled in the art.
In at least one embodiment the method of making paper products from pulp comprises the steps of forming an aqueous cellulosic papermaking furnish, pretreating the filler slurry according at least one of the methods and compositions described in U.S. patent application Ser. No. 12/323,976, or preflocculated according at least one of the methods and compositions described in U.S. Pat. No. 8,172,983, combined with the addition of natural gums and wet web strength agent, wet strength agent, dry strength agent or draining aids to the furnish, draining the furnish to form a sheet and drying the sheet. The steps of forming the papermaking furnish, draining and drying may be carried out in any conventional manner generally known to those skilled in the art.
EXAMPLES
The foregoing may be better understood by reference to the following examples, which are presented for purposes of illustration and are not intended to limit the scope of the invention.
Unless otherwise stated, the following is the general procedure used for all handsheet studies. A filler stock was prepared using Albacar HO PCC as filler. The fiber stock was a 75/25 HWK/SWK blend. Sheet basis weight was maintained at around 80 g/m 2 . Six replicate handsheets were produced for each experimental condition. The thin stock for each bulk handsheet was mixed in a dynamic drainage jar at 800 rpm. For the basesheets, the desired amount of PCC, natural gum/GPAM, cationic starch, alkenyl succinic anhydride, and a cationic flocculant were added in 15-second intervals. After mixing, the basesheet was formed in a handsheet mold using an 80-mesh screen. Once formed the sheets were pressed in a static press at 0.565 MPa for 5 minutes and then dried in a drum drier at 210° F. for one minute. Sheet strength measurements were conducted at 50% relative humidity at 23° C.
TSI means tensile strength index measured in N·m/g. ABL, is the measurement of abrasion loss, which was measured according to TAPPI test method. T476 which is a measure of surface strength. ABL is measured in units of mg/1000 revs. The lower the abrasion loss, the stronger the surface is.
Example 1
This study was designed to show the strength performance of the natural gum when it is used to treat the filler before addition to the fiber slurry and a strength aid is added to the wet end. Table 1 summarizes the experimental design and measured results.
TABLE 1 Experimental Design and Results Experimental Design Measured Results Target True Filler ash GPAM ash Predicted ZDT # treatment (%) (lb/ton) (%) opacity Brightness TSI (kPa) ABL 1 Untreated 20 0 16.4 93.99 89.68 34.1 512 623 2 Untreated 30 0 25.4 95.41 90.25 24.3 427 1363 3 Xanthan 20 1 17.1 94.04 89.16 35.6 506 498 gum 4 Xanthan 30 0 24.6 95.06 90.32 27.7 444 983 gum 5 Untreated 20 6 18.1 94.46 88.99 32.7 511 471 6 Untreated 30 6 28.4 95.25 90.97 22.7 412 1346 7 Xanthan 20 6 18.5 93.66 89.41 37.0 541 296 gum 8 Xanthan 30 6 27.5 94.94 90.48 28.3 457 784 gum
The results of this example demonstrate that the combination of a natural gum (whose representative example is xanthan but is assumed to apply to many or all natural gums) with a strength additive (whose representative example is GPAM but is assumed to apply to many or all natural gums) results in an unexpected synergistic effect. When both are applied to the furnish the effect was better than if either were added alone. Adding GPAM alone in the wet end produced almost no beneficial effect. Adding xanthan alone in the wet end produced a small benefit. The combination of GPAM with xantham however produced a large effect far out of proportion to the individual contributions of either. This large effect demonstrates a novel unexpected synergy results from their combination.
Example 2
This study was designed to show the performance of the natural gum and the strength aid independently of the feed point of the natural gum. Table 2 summarizes the conditions and results. TSI means tensile strength index measured in N·m/g. ABL in in the final column is the measurement of abrasion loss. ABL was measured according to LEON test method T476 which is a measure of surface strength. TSI is measured in terms of mg/1000 revs. The lower the abrasions loss, the stronger the surface is. True ash is a measure of how much of the added filler actually end up in the resulting paper sheet.
TABLE 2 Experimental Design and Results Experimental Design Filler treatment Wet end Measured Results xanthan xanthan True Target gum gum GPAM Ash Opacity ZDT # Ash % (lb/ton) (lb/ton) (lb/ton) (%) at 80 gsm Brightness TSI (kPa) ABL 1 20 0 0 0 18.7 93.98 90.15 30.8 473 764 2 30 0 0 0 28.2 95.10 90.97 22.0 365 1664 3 20 0 1 6 19.6 93.49 89.85 35.0 510 395 4 30 0 1 6 28.3 94.77 90.96 25.2 434 935 5 20 0.6 0 6 18.8 93.23 89.75 35.9 520 362 6 30 0.9 0 6 29.0 94.63 90.75 26.9 445 846
This example demonstrates that for paper sheets having similar True Ash levels, the natural gum-strength additive synergy manifests if the natural gum is added in either to the filler before it contacts the paper material or within the wet end of the papermaking process.
Example 3
The following study was designed to compare the performance of two distinct natural gums, namely, xanthan gum and guar gum. A strength aid is immediately added in each case when a natural gum is added in the wet end. Table 3 summarizes the experimental design and results.
TABLE 3 Experimental Design and Results Experimental Design Target Xanthan Guar Measured Results Ash gum gum GPAM True ZDT # (%) (lb/t) (lb/t) (lb/t) ash (%) TSI (kPa) ABL 1 20 0 0 0 18.9 31.7 497 1792 2 30 0 0 0 27.7 23.8 410 2917 3 20 1 0 6 19.4 36.2 551 1372 4 30 1 0 6 28.1 26.0 473 2272 5 20 0 1 6 18.7 35.6 547 1435 6 30 0 1 6 27.7 25.6 455 2423
The results of this example show that the synergy displayed by xanthan is representative of a property that is shared by many or all natural gums.
Example 4
This study was designed to map the performance of the natural gum-strength aid as a function of both chemistries. Table 4 summarizes the experimental design and results.
TABLE 4
Experimental Design and Results.
Experimental Design
Measured Results
Xanthan
True
Filler
Target
gum
GPAM
Ash
ZDT
#
Treatment
Ash (%)
(lb/t)
(lb/t)
(%)
TSI
(kPa)
ABL
1
Untreated
20
0.00
0
16.5
33.6
503
966
3
Untreated
25
0.00
0
20.5
29.5
481
1288
2
Untreated
30
0.00
0
24.2
25.7
442
1601
3
Untreated
25
0.00
0
20.5
29.5
481
1288
4
Untreated
25
0.00
2
21.6
29.8
484
1211
5
Untreated
25
0.00
4
22.0
27.8
470
1243
6
Untreated
25
0.91
0
20.4
30.7
494
1111
7
Untreated
25
0.91
2
21.9
31.0
514
1000
8
Untreated
25
0.91
4
22.0
31.1
521
980
9
Xanthan
25
0.00
0
21.5
30.3
493
1192
gum
10
Xanthan
25
0.00
12
22.5
31.5
498
1101
gum
11
Xanthan
25
0.00
4
22.8
32.3
506
986
gum
Example 5
This study was designed to show the performance of guar gum addition to the stock followed by a strength aid. Table 5 summarizes the experimental design and results.
TABLE 5
Experimental Design and Results.
Experimental
Design
Guar gum
GPAM
Measured Results
#
(lb/t)
(lb/t)
Ash (%)
TSI
ZDT (kPa)
ABL
1
0
0
16.5
34.6
513
1006
2
0
0
25.5
26.4
420
1675
3
0
0
21.2
29.8
469
1298
4
1
0
20.9
31.2
471
1281
5
0
4
22.7
30.1
485
1252
6
1
4
22.9
31.9
497
1107
A person of ordinary skill in the art will recognize that all of the previously described methods are also applicable to paper mat comprising other non-cellulose based fibrous materials, paper mats comprising a mixture of cellulose based and non-cellulose based fibrous materials, and/or synthetic fibrous based materials.
While this invention may be embodied in many different forms, there described in detail herein specific preferred embodiments of the invention. The present disclosure is an exemplification of the principles of the invention and is not intended to limit the invention to the particular embodiments illustrated. All patents, patent applications, scientific papers, and any other referenced materials mentioned herein are incorporated by reference in their entirety. Furthermore, the invention encompasses any possible combination of some or all of the various embodiments described herein and/or incorporated herein. In addition the invention encompasses any possible combination that also specifically excludes any one or more of the various embodiments described herein and/or incorporated herein.
The above disclosure is intended to be illustrative and not exhaustive. This description will suggest many variations and alternatives to one of ordinary skill in this art. The compositions and methods disclosed herein may comprise, consist of or consist essentially of the listed components, or steps. As used herein the term “comprising” means “including, but not limited to”. As used herein the term “consisting essentially of” refers to a composition or method that includes the disclosed components or steps, and any other components or steps that do not materially affect the novel and basic characteristics of the compositions or methods. For example, compositions that consist essentially of listed ingredients do not contain additional ingredients that would affect the properties of those compositions. Those familiar with the art may recognize other equivalents to the specific embodiments described herein which equivalents are also intended to be encompassed by the claims.
All ranges and parameters disclosed herein are understood to encompass any and all subranges subsumed therein, and every number between the endpoints. For example, a stated range of “1 to 10” should be considered to include any and all subranges between (and inclusive of) the minimum value of 1 and the maximum value of 10; that is, all subranges beginning with a minimum value of 1 or more, (e.g. 1 to 6.1), and ending with a maximum value of 10 or less, (e.g. 2.3 to 9.4, 3 to 8, 4 to 7), and finally to each number 1, 2, 3, 4, 5, 6, 7, 8, 9, and 10 contained within the range.
All numeric values are herein assumed to be modified by the term “about,” whether or not explicitly indicated. The term “about” generally refers to a range of numbers that one of skill in the art would consider equivalent to the recited value having the same function or result). In many instances, the term “about” may include numbers that are rounded to the nearest significant figure. Weight percent, percent by weight, % by weight, wt %, and the like are synonyms that refer to the concentration of a substance as the weight of that substance divided by the weight of the composition and multiplied by 100.
As used in this specification and the appended claims, the singular forms “a,” “an,” and “the” include plural referents unless the content clearly dictates otherwise. Thus, for example, reference to a composition containing “a compound” includes a mixture of two or more compounds. As used in this specification and the appended claims, the term “or” is generally employed in its sense including “and/or” unless the content clearly dictates otherwise.
This completes the description of the preferred and alternate embodiments of the invention. Those skilled in the art may recognize other equivalents to the specific embodiment described herein which equivalents are intended to be encompassed by the claims attached hereto. | The invention provides a method of improving dewatering efficiency, increasing sheet wet web strength, increasing sheet wet strength and enhancing filler retention in a papermaking process. The method improves the efficiency of drainage aids or wet web strength aids or wet strength aid by coating at least some of the filler particles with a natural gum and with a material that prevents the filler materials form adhering to those additives. The drainage additive or wet web strength additive or wet strength aid holds the cellulose fibers together tightly and is not wasted on the filler particles. | 3 |
RELATED APPLICATIONS
[0001] The present application is a continuation-in-part application of U.S. application Ser. No. 12/668,890 filed Jan. 13, 2010 as a National Stage Application of PCT/ES08/00469, filed Jul. 1, 2008, claiming priority of Spanish Application No. P200701966, filed Jul. 13, 2007.
FIELD OF THE INVENTION
[0002] The technical field of the present invention pertains to a holder, which is integrated into the framework of floating slabs in the form of a poured concrete forgings, as a mechanical accessory for raising the forging once the concrete has set. These floating slabs are arranged in constructions that require an insulation of the central block, as they may be the supporting bases on which are situated electric transformers, air conditioning units, bowling alleys and, generally, sites at which it is desired to avoid the transmission of vibrations and impact noises. The technical field of the present invention pertains to a holder, which is integrated into the framework of floating slabs, and includes an accessory for raising the slab once the concrete has set. These floating slabs are arranged in constructions that require an insulation of the central block, as they may be the supporting bases on which are situated electric transformers, air conditioning units, bowling alleys and, generally, sites where it is desired to avoid the transmission of vibrations and impact noises.
BACKGROUND OF THE INVENTION
[0003] The system of creating floating slabs by means of distributing metallic containers in welded wire fabric in the form of hollow cubes that are within the forging is known. The raising phase occurs once the concrete has set, and mechanical accessories in the form of shock-absorbing elements are positioned in the hollow interiors of the holders which are coupled under beveled ribs that are located in two of the corners thereof. In this way, the raising of the floating slab will be achieved to the extent desired by means of the pressure of the shock absorbers in its upper part.
[0004] The welded wire fabric is usually formed by two mesh structures, each of which are created by wires that intersect one another at right angles, forming grids, whose points of contact are joined by welding. These are positioned superimposed, trying to align the grids of the two meshes for the correct insertion of holders which have a height equal to the height of the slab containing the welded wire fabrics, and are positioned within the interstices of the two meshes, so that, after the setting of the concrete, the meshes are closely aligned in the slab. For this purpose, a plurality of metallic rods are installed welded on the surface of each holder in the horizontal direction which protrude from their structure. In fixing to the rebar, in order to avoid the displacement thereof in the pouring phase of the concrete, once in the grid, the rods are fastened to the welded wire fabric by means of wires. This involves a lot of work for the operator in the positioning and a limited rigidity of the system, causing the holders to move when the concrete is poured or by the operator's own movements within the rebar. If the setting occurs with any of these elements displaced or twisted, there will be a weak zone at this point which may cause the fracture of the floating slab in the raising phase.
[0005] The grid of the welded wire fabric is produced by having different proportions. The prior-art system has the drawback that the rods welded to the structure of the holder are arranged so that they overlie the grid in every case, to facilitate its bundling by means of wire. For this the operator usually has problems at the time of fitting the holder in the welded wire fabric, and has to shorten the rebar to make a suitable cavity in the mesh to receive he holder. Apart from the labor-intensive work that it involves, it results in a structure that is hazardous to the work zone. Where the ends of the rods are welded together, and where the cuts made in the rebar result in many sharp points, thee is a risk to the operator in the work of positioning the wires or merely by the operator's being situated on the structure.
[0006] The welded wire fabric is manufactured in different extension dimensions for the different positioning sites. For this, the bonding of one surface of the welded wire fabric with those surfaces which follow it in the work is necessary. It is equally necessary to anchor the corners of the layers of the welded wire fabric, if a worker or operator goes through zones remote from the center, and creates a force on one or both of the layers, this force then causes the structure to rise.
[0007] Another type of element is known for positioning shock absorbers in the forging that is made up of a metallic cylinder with walls of considerable size, within which the shock absorber is arranged, having two horizontal projections in its contour for being situated in the rebar. The complexity of this structure makes the manufacture thereof very expensive, and the securing in the welded wire fabric, in spite of the weight that it has, is insufficient.
DESCRIPTION OF THE INVENTION
[0008] The present invention that is proposed fully solves the problems mentioned by presenting a holder in the form of a holder which has various horizontal tubes in its perimetral structure, at various levels. The tubes are suitable to receive rods being inserted therein, which rods may project beyond the sides of the holder for supporting the different layers of welded wire fabric above them. In this way, the first layer of the welded wire fabric will rest on the rods arranged in the lower tubes of the holder, which are facing on two of its sides; a second welded wire fabric arranged above the rods of the upper tubes, placed on the other two opposite sides of the holder.
[0009] The bonding of the different mesh structures of the work is carried out by means of the rods installed in the lower tubes which support the first welded wire fabric, which connect the holders of the adjoining mesh surfaces.
[0010] Rods will be placed in the upper tubes parallel to the above tubes for the bonding of two adjacent holders which are close to the corners of two welded wire fabric surfaces. This upper linking together will prevent the raising of the mesh when a pressure goes or is applied outside of the central zone.
[0011] The object of the present invention is accomplished with a lid and a supporting base for the interior insulation in the pouring of the concrete.
DESCRIPTION OF THE DRAWINGS
[0012] To complement the description that is being provided and to aid in a better understanding of the features of the present invention, the present specification is accompanied by drawings showing the preferred embodiment, in which, in an illustrative and nonlimiting nature:
[0013] FIG. 1A shows the left elevation; FIG. 1B shows the front elevation; and FIG. 1C shows the plan view of the holder that is the subject of the present invention;
[0014] FIG. 2 is a perspective view showing the positioning of eight holders in a first phase of the creation of the forging prior to the installation of the lower and upper woven wire mesh sections;
[0015] FIG. 3 is a perspective view showing the bonding of two adjoining sections of the first (lower) mesh of the forging with the surfaces of the two sections aligned in coplanar relation;
[0016] FIGS. 3A and 4A are sectional views taken on the lines 3 A- 3 A and 4 A- 4 A of FIG. 3 , showing the next step in the creation of the forging, when both the first (lower) and the second (upper) meshes are mounted on the holders;.
[0017] FIG. 5 is a perspective view showing the creation of a modified embodiment of the forging, which uses rods in all of the eight tubes of the holder of the present invention; and
[0018] FIG. 5A is a sectional view taken on the line 5 A- 5 A of FIG. 5 .
PREFERRED EMBODIMENT OF THE INVENTION
[0019] Viewing the figures shown, it can be seen how the holder ( 6 ) for positioning floating slabs is composed of a metallic hollow cube having beveled ribs ( 6 ′) to mount the mechanical accessories used in the raising phase. The cube 6 is smaller in outride dimensions than the interstice of the grid of the mesh and has a height equal to that of the forging which forms the slab. The four sides of the holder have identical tubes ( 1 , 1 ′, 2 , 2 , 33 ′, 4 , 4 ′), which are preferably attached to the holder 6 by means of welding.
[0020] The first (lower) mesh of the welded wire fabric ( 7 , 8 ) is situated above the rods ( 5 ) mounted in the lower tubes ( 1 , 1 ′), according to FIGS. 3 , 3 A and 4 A.
[0021] As shown in FIG. 3 , both sections (I and II) of the first mesh ( 7 , 8 ) of the structure of the welded wire fabric is situated above rods ( 5 ) which are inserted in the lower tubes ( 1 and 1 ′) shown in FIG. 2 . As shown in FIG. 3A , the adjoining sections (I and II) of the second mesh grid ( 13 ) are not interconnected prior to installation, and are situated above the rods ( 5 ) which are inserted in the lower tubes 2 and 2 ′.
[0022] To interconnect the adjoining mesh sections (I and II), the rods ( 5 ) will be inserted in the lower tubes of the holders ( 6 ) in both sections (I and II), spanning between and connecting both sections of the mesh structure.
[0023] The mesh is formed by longitudinal wires ( 8 ) and transverse wires ( 7 ), arranged some on top of others, and securing the bonding at the points of contact by welding. As shown in FIG. 4A , the rods ( 5 ) in the lower tubes ( 1 and 1 ′) will be situated on the same plane and parallel to the lower wires ( 8 ) of the mesh, holding the longitudinal wires perpendicular to the transverse ones ( 7 ).
[0024] The separation between the lower tubes and upper tubes for positioning the mesh will be sufficient for the entry of the concrete, on the understanding that there may be little separation between the holders in the pouring which will put the consistency of the future floating slab at risk.
[0025] In the holders ( 6 ) belonging to two mesh sections that are located close to the corners, rods ( 5 ) will be inserted into the upper tubes ( 2 , 2 ′). As shown in FIGS. 5 and 5A , additional rods 5 (not shown in FIGS. 3 , 3 A and 4 A) may be inserted in the tubes ( 3 , 3 ′) on the same side as the lower tubes ( 5 , 5 ′), whose rods support the first mesh, and inserted in the two adjacent sections It will also be used for anchoring the structure and the mesh is not raised when exerting pressure in an opposite zone. In FIG. 3 is only shown the first (lower) welded wire mesh ( 7 , 8 ), FIGS. 3A and 3B illustrate the second (upper) mesh ( 7 , 8 ) superimposed on the upper rods ( 5 ) in the manner that is described.
[0026] FIG. 3 shows two joined mesh sections (I, II) beginning at the joined corners, and it has to be understood that the sections (I, II) are not shown complete in the horizontal direction.
[0027] As shown in FIGS. 5 and 5A , the other two tubes ( 4 , 4 ′) that are in the structure of the holder ( 6 ), arranged parallel to the upper tubes ( 2 . 2 ′) for the installation of the rods that support the second mesh and in a plane lower than those will be used for the installation of other additional rods when the slab has to support major loads.
[0028] The holder has a lid and a holder base coated with rustproof paint, and both are assembled by compression to avoid the entrance of the pourable concrete mix. As a complement, the lid is arranged sealed with silicone. The lid and holder base are painted different colors for quickly checking before pouring the concrete whether any of the holders are in the incorrect position.
[0029] When the concrete has set, the lids of the holders will be removed, and shock absorbers will then be placed which will make the raising of the slab possible. In this most suitable embodiment, another shock absorber, in this case, a high-frequency, silent-block-type shock absorber, will be placed on the bottom, which will facilitate the movement of the shock absorber arranged above same.
[0030] It should be understood that the present invention was described according to the preferred embodiment of same; therefore, it may be susceptible to modifications in shape, size and materials, provided that said changes do not substantially vary the features of the present invention as they are claimed below. | A holder to be placed in floating floor slabs and the installation system thereof, the holder comprising a cubic holder having a pair of tubes on each side thereof, parallel with the supporting base, with facing sides in identical position; within said sides a section designed for placing rods on which the different layers of the rebar mesh are supported and a system for fitting the mesh on the rods, and also the securing of the corners of the different levels of the rebar mesh by means of linking of the holder s using the rods. | 4 |
CLAIM OF BENEFIT TO PRIOR APPLICATIONS
This application is a continuation application of U.S. patent application Ser. No. 14/331,194, filed Jul. 14, 2014, now published as U.S. Publication 2015/0009724. U.S. patent application Ser. No. 14/331,194 is a continuation application of U.S. patent application Ser. No. 13/276,885, filed on Oct. 19, 2011, now issued as U.S. Pat. No. 8,811,047. U.S. patent application Ser. No. 13/276,885 is a continuation application of U.S. patent application Ser. No. 12/160,743, filed on May 4, 2010, now issued as U.S. Pat. No. 8,089,785. U.S. patent application Ser. No. 12/160,743 is a national stage application of PCT Application PCT/GB2007/050014, filed Jan. 12, 2007, now published as WO 2007/080429. PCT Application PCT/GB2007/050014 claims the benefit of United Kingdom Patent Application GB 0600658.9, filed Jan. 13, 2006. U.S. Publication 2015/0009724 and U.S. Pat. Nos. 8,811,047 and 8,089,785 are incorporated herein by reference.
BACKGROUND
The present invention relates to a power conditioning unit for delivering power from a dc power source to an ac output, particularly suitable for ac voltages greater than 50 volts, either for connecting directly to the mains or grid utility supply, or for powering mains devices directly, independent from the mains utility supply.
A number of power electronics converters have been produced in the past for research or commercial purposes, see for example EP0780750, EP0947905, and JP2000020150. In these solutions a capacitor is used as a reservoir and for filtering of high frequency currents. Further information may be found in US2005/0068012, JP05003678, GB2415841 and WO2006/011071. However, attention is not directly paid into the choice of capacitor and the control of energy input and output. It is common to encounter aluminum electrolytic capacitors in power supplies. These capacitors have lifetimes in the range of 2000 to 12000 hours, that is, up to 1.4 years of continuous service. In contrast other capacitor technologies, such as polyester, can achieve lifetimes of up to 500,000 hours or slightly more than 50 years. Therefore, it would be advantageous to provide a better lifetime of the power converter by using polyester or polypropylene capacitor. This is possible with the method of energy control explained herein.
We will describe a method to control direct current energy sources, in particular a method to control direct current energy sources that utilise power electronics converters to condition the input power into alternating current electricity that is supplied to the mains. Such power electronics converter comprises of a plurality of conversion stages and one energy reservoir in the form of a capacitor. The method presented allows the utilisation of long-lifetime polyester or polypropylene capacitors as opposed to short-lifetime electrolytic capacitors. The method consists of two control algorithms: one algorithm controls the power extracted from the energy source that is supplied to the energy reservoir and another controls the transfer of power from the reservoir into the electricity mains. We will describe controlling the voltage in the energy reservoir, as opposed to the supply voltage, which in turn controls the energy transfer. We will describe energy being supplied to the reservoir from the source (PV panel). To release that energy the voltage variation in the reservoir is used to define a current amplitude. We will describe how energy is stored in the power converter (in the energy reservoir) and how to use that energy to define a current injection into the mains.
According to an aspect of the invention, there is provided a power conditioning unit for delivering power from a dc power source to an ac mains power supply output, the power conditioning unit comprising an input for receiving power from said dc power source, an output for delivering ac power, an energy storage capacitor, a dc-to-dc converter having an input connection coupled to said input and an output connection coupled to the energy storage capacitor, and a dc-to-ac converter having an input connection coupled to said energy storage capacitor and an output connection coupled to said output, wherein said energy storage capacitor has a capacitance of less than twenty microfarads.
The ac mains power supply output may be connected to the utility grid, so that the power conditioning unit delivers power into the grid, or it may be a standalone power supply output for supplying power to electrical appliances.
The dc-to-dc converter may be configured to draw a substantially constant power from the dc power source regardless of a voltage on the energy storage capacitor. It may be configured to perform maximum power point tracking (MPPT) of the dc power source, and this may be achieved by maintaining a voltage or current from the dc power source substantially at a reference voltage or current. This may comprise controlling transistors in the dc-to-dc converter responsive both to the voltage or current from the dc power source and to a voltage or current to the energy storage capacitor.
The dc-to-ac converter may be configured to deliver a substantially sinusoidal current or voltage to the ac mains power supply output regardless of a voltage on the energy storage capacitor. This may be achieved by maintaining a current or voltage to the power supply output substantially at a reference sinusoid current or voltage. This may comprise controlling transistors in the dc-to-ac converter responsive both to a voltage or current from the energy storage capacitor and to the current or voltage to the power supply output.
The energy storage capacitor may comprise a non-electrolytic capacitor such as a film-type capacitor (for example polyester or polypropylene). The value of the capacitance may be directly proportional to the maximum power transfer capability, that is, the rated power of the apparatus. This value may be lower than an equivalent electrolytic capacitor in a conventional power conditioning unit with the same power rating. For example, less than 20 microfarads, less than 15 microfarads, less than 10 microfarads, less than 5 microfarads or another size available for a non-electrolytic capacitor.
According to another aspect of the invention, there is provided a dc-to-dc converter for delivering power from a dc power source to a dc output, the converter being configured to maintain a voltage on the dc power source substantially constant over a range of dc output voltages, the converter comprising an input for receiving power from said dc power source, an output for delivering dc power, at least one power device for transferring power from the input to the output, a sensing circuit for sensing a voltage on said input, and a driver circuit for driving said at least one power device responsive to said sensing to control said power transfer.
According to a further aspect of the invention, there is provided an inverter for delivering power from a dc power source to an ac output, the inverter being configured to maintain a substantially sinusoidal output voltage or current over a range of dc power source voltages, the inverter comprising an input for receiving power from said dc power source, an output for delivering ac power, at least one power device for transferring power from the input to the output, a low-pass filter coupled to said input, a sensing circuit for sensing an output from the low-pass filter and comparing with a reference, and a driver circuit for driving said at least one power device responsive to said sensing to control said power transfer.
According to a yet further aspect of the invention, there is provided a power conditioning unit for delivering power from a dc power source to an ac mains power supply output, wherein a link capacitor of the power conditioning unit connected in parallel between an output of a dc-to-dc converter of said power conditioning unit and an input of a dc-to-ac converter of said power conditioning unit is not an electrolytic capacitor.
According to another aspect of the invention, there is provided a method to control a power conditioning unit for delivering power from a dc source into the electricity supply, the power conditioning comprising the following: a plurality of inputs for connecting the dc power source, a plurality of output for connecting into the electricity supply, a power conversion stage for voltage conditioning of the dc power source, a power conversion stage for power injection into the electricity supply, a dc capacitor for energy buffering from the dc power source to the electricity supply.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention will now be described in detail, with reference to the accompanying drawings, in which:
FIG. 1 shows a dc to ac system according to the present invention.
FIG. 2 shows an example of a power conditioning unit suitable for control by the system of FIG. 1 .
FIG. 3 shows DC capacitor voltage according to the present invention.
FIG. 4 shows control block A according to the present invention.
FIG. 5 shows characteristics of photovoltaic panel array as known in the art.
FIG. 6 shows control block B according to the present invention.
FIG. 7 shows an exemplary implementation of control blocks A and B according to the present invention.
FIG. 8 shows output and input powers according to the present invention.
DETAILED DESCRIPTION
The present invention relates to a method of controlling the transfer of power from a dc energy source, such as a solar panel, fuel cell, dc wind turbine, etc, into the electricity mains supply, and in particular, this method allows the replacement of shortlifetime energy reservoirs for long-lifetime polyester or polypropylene capacitors.
The energy control method can be used in any power electronics converter device ( 1 ) as shown in FIG. 1 . This apparatus ( 1 ) is made of three major elements: a power converter stage A ( 3 ), one reservoir capacitor Cdc ( 4 ), and one power converter stage B ( 5 ). The apparatus ( 1 ) has a plurality of inputs connected to a direct current (dc) source, such as a solar or photovoltaic panel array ( 2 ) comprising one or more dc sources connected in series and/or in parallel. The apparatus ( 1 ) is also connected to the electricity supply ( 6 ) so that the energy extracted from the dc source ( 1 ) is transferred into the mains ( 6 ).
The power converter stage A ( 3 ) may be of different types: it can be a stepdown converter where the voltage at the input is decreased using some power electronics topology; it can be a step-up converter where the input voltage is amplified using a different type of power electronics circuit; or it can do both amplify and attenuate the input voltage. In addition, it may provide electrical isolation by means of a transformer or a coupled inductor. In whatever case, the electrical conditioning of the input voltage must be such that the voltage across the capacitor Cdc ( 4 ) remains higher than the grid voltage ( 6 ) magnitude at all times. Also, this block contains one or more transistors, inductors, and capacitors. The transistor(s) are driven through a pulse width modulation (PWM) generator. The PWM signal(s) have variable duty cycle, that is, the ON time is variable with respect to the period of the signal. This variation of the duty cycle effectively controls the amount of power transferred across the power converter stage A ( 3 ).
The power converter stage B ( 5 ) injects current into the electricity supply ( 6 ). Therefore, the topology utilises some means to control the current flowing from the capacitor Cdc ( 4 ) into the mains ( 6 ). The circuit topology can be either a voltage source inverter or a current source inverter.
FIG. 2 shows an example of a power conditioning unit to which the control system of FIG. 1 may be applied. Control A ( 7 in FIG. 1 ) may be connected to the input connections (e.g. gates or bases) of transistors in power converter stage A ( 21 ) to control the transfer of power from the dc energy source ( 20 ). The input of this stage is connected to the dc energy source and the output of this stage is connected to dc link capacitor 22 . This capacitor stores energy from the dc energy source for delivery to the mains supply ( 24 ). Control A may be configured to draw a substantially constant power from the dc energy source regardless of the dc link voltage Vdc on Cdc.
Control B ( 8 in FIG. 1 ) may be connected to the input connections of transistors in power converter stage B ( 23 ) to control the transfer of power to the mains supply. The input of this stage is connected to the dc link capacitor and the output of this stage is connected to the mains supply. Control B may be configured to inject a substantially sinusoidal current into the mains supply regardless of the dc link voltage Vdc on Cdc.
The capacitor Cdc ( 4 ) acts as an energy buffer from the input to the output. Energy is supplied into the capacitor via the power stage A ( 3 ) at the same time that energy is extracted from the capacitor via the power stage B ( 5 ). The current invention provides a control method that balances the average energy transfer and allows a voltage fluctuation, resulting from the injection of ac power into the mains ( 6 ), superimposed to the average dc voltage of the capacitor Cdc ( 4 ), as shown in FIG. 3 . The figure shows an average voltage of 475V and a 100 Hz fluctuation of peak amplitude of 30V. The peak amplitude depends on the amount of power being transferred from the input ( 2 in FIG. 1 ) to the output ( 6 ). The frequency of the oscillation can be either 100 Hz or 120 Hz depending on the line voltage frequency (50 Hz or 60 Hz respectively).
Two synchronised and independent control blocks control the system ( 1 ): a control block A ( 7 ) that directly controls the power stage A ( 3 ), and a control block B ( 8 ) that directly controls the power stage B ( 5 ).
Control block A ( 7 ) has the configuration shown in FIG. 4 . It comprises an adder ( 31 ), a negative proportional gain ( 32 ), a PWM generator ( 33 ), the system plant ( 34 ), and a feedback gain ( 35 ). This control block regulates the voltage across the dc source ( 2 ). This voltage, vin, is measured and adjusted by gain k1 ( 35 ). It is then subtracted to a voltage reference, vref, using the adder ( 31 ). The error, (vref−k1vin), is then amplified by a factor of −k2. The resulting signal is negatively proportional to the error. Therefore, a positive error generates a decrement in the driving signal and conversely. This driving signal is input to a PWM generator ( 33 ) that can be a microcontroller, or a PWM integrated circuit. This block generates digital pulses that, in turn, drive the transistors of the power stage A ( 3 ) that is equivalent to the plant ( 34 ).
Controlling the dc source ( 2 ) voltage directly controls the power being transferred across power stage A ( 3 ) as is shown in FIG. 5 for a photovoltaic panel array.
Control block B ( 8 ) has the configuration shown in FIG. 6 . It composes of an adder ( 41 ), a sample and hold (SH) with period T block ( 42 ), a proportional-derivative (PD) compensator ( 43 ), the system plant ( 44 ), a low-pass filter (LPF) feedback block ( 45 ). This control block regulates the average voltage across capacitor Cdc ( 4 ). Because the voltage, vdc, contains the sum of a constant voltage and a fluctuating sinusoidal component, the signal is scaled and filtered using the LPF block ( 45 ). This generates a constant voltage that is compared against a reference, vdc_ref, using adder ( 41 ). The error is measured every T seconds using a Sample and Hold, SH, block ( 42 ). The resulting sampled error is forwarded to a PD compensator ( 43 ) that sets the amplitude of the current injected to the mains ( 6 ) via power stage B ( 5 ). The update of this current reference, Iref, amplitude is done every T seconds, which is the inverse of the line voltage frequency. Hence, it can take the values of 0.02 or 0.0167 seconds for a line frequency of 50 or 60 Hz respectively. This is needed in order to prevent current injection distortion.
An implementation of control blocks A and B is shown in FIG. 7 . Both blocks operate independently but share a common microcontroller for simplicity. The microcontroller performs the control strategy depicted in FIG. 6 for block B. In addition the microcontroller could incorporate some means of maximum power point tracking control in case the input source is a photovoltaic panel in block A in order to generate a reference input voltage used in FIG. 4 . Consequently the input voltage and current and the dc-link voltage are fed into the microcontroller via an arrangement of operational amplifiers or signal conditioning blocks.
The control shown in FIG. 4 for block A is implemented using analogue electronics in the form of operational amplifiers and the phase-shift pwm controller depicted in FIG. 7 ( 51 ). As mentioned before, the input voltage reference is obtained through the microcontroller via a digital to analogue converter (DAC). The proportional error is obtained inside the phase-shift pwm controller that, in turn, generates pwm signals for the transistors of stage A ( 21 ).
Implementation of control B ( 52 ) includes a current transducer that senses the rectified output current. This signal is conditioned to appropriate voltage levels using operational amplifiers and is then compared against a reference current. The reference current is generated in the microcontroller by an algorithm shown in FIG. 6 and the resulting digital word is sent to a DAC in order to get an analogue, instantaneous, current reference. Changes to the current magnitude are done in a periodic basis (with period equal to the grid voltage period) in order to avoid current distortion. The result of the comparison between the reference and the actual current is buffered through a D flip-flop which, in turn, drives transistor Q 9 in FIG. 2 . Transistors Q 5 -Q 8 form a full-bridge that switches at line frequency using an analogue circuit synchronised with the grid voltage. Transistors Q 5 and Q 8 are on during the positive half cycle of the grid voltage and Q 6 and Q 7 are on during the negative half cycle of the grid voltage.
FIG. 8 shows the output and input powers using the aforementioned control. Clearly, the instantaneous power output is a sinusoid superimposed to an average positive value. In contrast, the input is constant throughout the period of the line voltage. The power difference creates and energy mismatch that is absorbed in capacitor Cdc. This effectively appears as a fluctuation across the capacitor, as is shown in FIG. 3 .
No doubt many other effective alternatives will occur to the skilled person. It will be understood that the invention is not limited to the described embodiments and encompasses modifications apparent to those skilled in the art lying within the spirit and scope of the claims appended hereto. | The present invention relates to a power conditioning unit for delivering power from a dc power source to an ac output, particularly ac voltages greater than 50 volts, either for connecting directly to a grid utility supply, or for powering mains devices independent from the mains utility supply. We describe a power conditioning unit for delivering power from a dc power source to an ac mains output, the power conditioning unit comprising an input for receiving power from said dc power source, an output for delivering ac power, an energy storage capacitor, a dc-to-dc converter having an input connection coupled to said input and an output connection coupled to the energy storage capacitor, and a dc-to-ac converter having an input connection coupled to said energy storage capacitor and an output connection coupled to said output, wherein said energy storage capacitor has a capacitance of less than twenty microfarads. | 7 |
RELATED APPLICATION
This application claims priority from Korean Patent Application No. 10-2004-24595, filed on Apr. 9, 2004, the content of which is herein incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
This invention generally relates to semiconductor devices and methods of fabricating the same and, more specifically, to transistors with surrounded channel regions and methods of fabrication therefor.
As the size of transistors has decreased, short channel effects may extend relatively deep into the devices. In particular, as junction depths have become shallow, leakage current and source/drain resistance have generally increased. In addition, the performance of transistors is closely related with drive currents and the drive current of transistors has generally decreased with reduced channel width.
To address these problems, transistors with various structures have been introduced. In a partially insulated field effect transistor (PiFET), an insulating layer is formed under a channel and has a structure capable of preventing a punch-through phenomenon between source and drain. However, this structure is generally not suitable for a high-performance transistor because the reduction of a drain current due to the reduction of the channel width still remains a problem.
In a conventional gate all around type transistor, a gate surrounds a channel. In such a transistor, a gate electrode is formed in two sides or three sides of a fin-shaped channel, thus increasing the channel length without unduly increasing the planar area of the transistor. A fin field effect transistor (FinFET) having an active region with a fin-shaped extending vertically can reduce the width of a fin needed to form a fully depleted channel. As a result, short channel effect can be reduced. Techniques for fabricating gate all around type transistors are disclosed in Korean Patent Application No. 2001-0019525 entitled “A SEMICONDUCTOR DEVICE HAVING GATE ALL AROUND TYPE TRANSISTOR AND METHOD OF FABRICATING THE SAME” and U.S. Pat. No. 6,605,847 entitled “SEMICONDUCTOR DEVICE HAVING GATE ALL AROUND TYPE TRANSISTOR AND METHOD OF FORMING THE SAME”.
FIGS. 1A to 4A are plan views illustrating a fabricating method of a conventional gate all around type transistor, FIGS. 1B to 4B and 1 C to 4 C are cross-sectional views of the structures illustrated in FIGS. 1A to 4A in X and Y directions, respectively. Referring to FIGS. 1A , 1 B, and 1 C, an active layer pattern is formed on a lower substrate 10 and a buried oxide layer 12 . The active layer pattern includes a stacked structure including a silicon-germanium layer 14 and a silicon layer 16 . A surface of the active layer pattern is oxidized to form an insulating layer 18 . Referring to FIGS. 2A , 2 B, and 2 C, after forming an etch barrier layer on the substrate, the etch barrier layer in a gate region is removed to form an etch barrier pattern 20 . A portion of the insulating layer 18 covering the gate region is removed to expose the silicon-germanium layer 14 and the silicon layer 16 . The silicon-germanium layer 14 is selectively removed to form a hollow 24 using an isotropic etch process. Because an isotropic etch process is performed to form the hollow 24 , the gate region preferable is narrow in exposed width. In order to secure a desired channel length, it is typically required to expose a narrower width than the desired channel length.
Referring to FIGS. 3A , 3 B, and 3 C, a gate insulating layer 26 is formed on a surface of an exposed silicon layer 16 . A conductive layer 28 that fills in the gate region and the hollow is formed. Referring to FIGS. 4A , 4 B, and 4 C, the conductive layer 28 is removed using an anisotropic etch process or a chemical mechanical polishing (CMP) method to expose the etch barrier pattern 20 . The exposed etch barrier layer 20 is removed to expose an active pattern. As shown in FIGS. 4A , 4 B, and 4 C, a gate electrode 30 is formed on the active pattern. The gate electrode extends along sidewalls of the active pattern and fills in the hollow 24 . Accordingly, a channel may be formed at three sides of the active pattern as well as the hollow. Source/drains may be formed at an active region at both sides of the gate electrode.
As shown, a channel length in the hollow is different from that in three sides of the active pattern. As previously mentioned, while selectively etching silicon-germanium, an isotropic etch process is performed in source/drain directions. If the active pattern is thick in the hollow in order to increase a channel width, under-cut will be more pronounced in the source/drain directions. As a result, as the channel width is increased, a width difference of a gate electrode between the hollow and an upper portion of the active pattern is increased.
It is believed that these problems are not recognized in the conventional art. In the event that source/drain are aligned and formed at the gate electrode over the active region, an overlap capacitance between the gate electrode formed at the hollow and source/drain may be increased. As a result, speed of transistors may be limited. In addition, because a part of a gate insulating layer is overlapped with source/drain, reliability may be reduced.
SUMMARY OF THE INVENTION
In some embodiments of the present invention, a transistor includes spaced-apart impurity-doped first semiconductor material regions, e.g., impurity-doped silicon-germanium regions, disposed on a substrate. A second semiconductor material region, e.g., a silicon region, is disposed on and extends between the spaced-apart impurity-doped first semiconductor material regions. A gate insulating layer conforms to at least a top surface and sidewalls of a portion of the second semiconductor material region disposed between the impurity-doped first semiconductor material regions. A gate electrode is disposed on the gate insulating layer on the at least a top surface and sidewalls of the portion of the second semiconductor material region between the impurity-doped first semiconductor material regions. Source/drain regions are disposed in the second semiconductor material region on respective sides of the gate electrode. The impurity-doped first semiconductor material regions may have a different dopant concentration than the source/drain regions. In some embodiments, the gate electrode surrounds the portion of the second semiconductor material region disposed between the impurity-doped first semiconductor material regions. In other embodiments, an insulating region is disposed between the substrate and the portion of the second semiconductor material region disposed between the impurity-doped first semiconductor material regions.
In further embodiments of the present invention, the impurity-doped first semiconductor material regions include a first pair of spaced-apart impurity-doped first semiconductor material regions disposed on the substrate. The second semiconductor material region includes a first second semiconductor material region disposed on and extending between the first pair of impurity-doped first semiconductor material regions. The impurity-doped first semiconductor material regions further include a second pair of spaced-apart impurity-doped first semiconductor material regions disposed on the first second semiconductor material region. The second semiconductor material region further includes a second second semiconductor material region disposed on and extending between the second pair of impurity-doped first semiconductor material regions. The gate insulating layer conforms to at least a top surface and sidewalls of a portion of the second second semiconductor material region disposed between the second pair of impurity-doped first semiconductor material regions and sidewalls of a portion of the first second semiconductor material region disposed between the first pair of impurity-doped first semiconductor material regions. The gate electrode is disposed on the gate insulating layer on at least the top surface and sidewalls of the portion of the second second semiconductor material region between the second pair of impurity-doped first semiconductor material regions and the sidewalls of the portion of the first second semiconductor material disposed between the first pair of impurity-doped first semiconductor material regions. The source/drain regions include first and second pairs of source/drain regions in the respective first and second second semiconductor material regions, respective ones of each pair disposed on respective sides of the gate electrode.
In some method embodiments of the present invention, transistors are fabricated. An elongate stacked semiconductor structure is formed on a substrate. The stacked semiconductor structure includes a second semiconductor material region disposed on a first semiconductor material region. The first semiconductor material region is selectively doped to produce spaced-apart impurity-doped first semiconductor material regions and a lower dopant concentration first semiconductor material region therebetween. Etching exposes a portion of the second semiconductor material region between the impurity-doped first semiconductor material regions. The etching removes at least a portion of the lower dopant concentration first semiconductor material region to form a hollow between the substrate and the portion of the second semiconductor material region between the impurity-doped first semiconductor material regions. An insulation layer that surrounds the exposed portion of the second semiconductor material region between the impurity-doped first semiconductor material regions is formed. A gate electrode that conforms to the insulation layer and fills the hollow is formed. Source/drain regions are formed in the second semiconductor material regions on respective sides of the gate electrode. The doping of the impurity-doped first semiconductor material regions may provide an etching selectivity with respect to the lower dopant concentration first semiconductor material region in the etching, e.g., the selective doping may cause directional (anisotropic) etching.
The selective doping may include forming a dummy gate electrode pattern that transversely crosses the stacked semiconductor structure and implanting impurities into the first semiconductor material region using the dummy gate electrode pattern as an implantation mask. The etching may be preceded by forming an isolation region around the stacked semiconductor structure, and the etching may include forming an etching mask on the stacked semiconductor structure and the isolation region, the etching mask having an opening therein that transversely crosses the stacked semiconductor and exposes the isolation region on respective sides of the stacked semiconductor structure, and etching through the opening in the etching mask to remove portions of the isolation region and expose sidewalls of the portion of the second semiconductor material region disposed between the impurity-doped first semiconductor material regions and to form the hollow between the substrate and the portion of the second semiconductor material region between the impurity-doped first semiconductor material regions. The method may include forming a stacked semiconductor structure including more than two semiconductor material regions, and forming multiple channel regions using selective doping and etching.
In further method embodiments of the present invention, an elongate stacked semiconductor structure is formed on a substrate, the stacked semiconductor structure including a second semiconductor material region disposed on a first semiconductor material region. The first semiconductor material region is selectively doped to produce spaced-apart impurity-doped first semiconductor material regions and a lower dopant concentration first semiconductor material region therebetween. Etching exposes a portion of the second semiconductor material region between the impurity-doped first semiconductor material regions, wherein the etching removes at least a portion of the lower dopant concentration first semiconductor material region to form a hollow between the substrate and the portion of the second semiconductor material region between the impurity-doped first semiconductor material regions. An insulation layer that surrounds the exposed portion of the second semiconductor material region between the impurity-doped first semiconductor material regions is formed. An insulation region is formed in the hollow between the substrate and the portion of the second semiconductor material region between the impurity-doped first semiconductor material regions. A gate electrode that conforms to the insulation layer on top and sidewall surfaces of the portion of the second semiconductor material region between the impurity-doped first semiconductor material regions is formed. Source/drain regions are formed in the second semiconductor material regions on respective sides of the gate electrode.
BRIEF DESCRIPTION OF THE DRAWINGS
FIGS. 1A-4A are plan views of fabrication products illustrating exemplary operations for fabricating a conventional gate all around type transistor.
FIGS. 1B-4B are cross sectional diagrams of the fabrication products of FIGS. 1A-4A in an X direction.
FIGS. 1C-4C are cross sectional diagrams of the fabrication products of FIGS. 1A-4A in a Y direction.
FIG. 5A is a plan view of a transistor according to first embodiments of the present invention.
FIG. 5B is a cross-sectional view taken along line I-I′ of FIG. 5A .
FIG. 5C is a cross-sectional view taken along line II-II′ of FIG. 5A .
FIGS. 6A-11A are plan views of fabrication products illustrating exemplary operations for fabricating the transistor of FIGS. 5A-5C .
FIGS. 6B-11B are cross-sectional views taken along line I-I′ of FIGS. 6A-11A .
FIGS. 6C-11C are cross-sectional views taken along line II-II′ of FIGS. 6A-11A .
FIG. 12A is a plan view of a transistor according to second embodiments of the present invention.
FIG. 12B is a cross-sectional view taken along line III-III′ of FIG. 12A .
FIG. 12C is a cross-sectional view taken along line IV-IV′ of FIG. 12A .
FIGS. 13A-18A are plan views of fabrication products illustrating exemplary operations for fabricating the transistor of FIGS. 12A-12C .
FIGS. 13B-18B are cross-sectional views taken along line III-III′ of FIGS. 13A-18A .
FIGS. 13C-18C are cross-sectional views taken along line IV-IV′ of FIG. 13A-18A .
FIG. 19A is a plan view of a transistor according to third embodiments of the present.
FIG. 19B is a cross-sectional view taken along line V-V′ of FIG. 19A .
FIG. 19C is a cross-sectional view taken along line VI-VI′ of FIG. 19A .
FIGS. 20A-25A are plan views of fabrication products illustrating exemplary operations for fabricating the transistor of FIGS. 19 A-A 9 C.
FIGS. 20B-25B are cross-sectional views taken along line V-V′ of FIGS. 20A-25A .
FIGS. 20C-25C are cross-sectional views taken along line VI-VI′ of FIGS. 20A-25A .
FIG. 26A is a plan view of a transistor according to fourth embodiments of the present invention.
FIG. 26B is a cross-sectional view taken along line VII-VII′ of FIG. 26A .
FIG. 26C is a cross-sectional view taken along line VIII-VIII′ of FIG. 26A .
FIGS. 27A-32A are plan views of fabrication products illustrating exemplary operations for fabricating the transistor of FIGS. 26A-26C .
FIGS. 27B-32B are cross-sectional views taken along line VII-VII′ of FIGS. 27A-32A .
FIGS. 27C-32C are cross-sectional views taken along line VIII-VIII′ of FIGS. 27A-32A .
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
The present invention now will be described more fully hereinafter with reference to the accompanying drawings, in which embodiments of the invention are shown. However, this invention should not be construed as limited to the embodiments set forth herein. Rather, these embodiments are provided so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. In the drawings, the thickness of layers and regions are exaggerated for clarity. Like numbers refer to like elements throughout. As used herein the term “and/or” includes any and all combinations of one or more of the associated listed items.
The terminology used herein is for the purpose of describing particular embodiments and is not intended to be limiting of the invention. As used herein, the singular forms “a”, “an” and “the” are intended to include the plural forms as well, unless the context clearly indicates otherwise. It will be further understood that the terms “includes” and/or “including,” when used in this specification, specify the presence of stated features, integers, steps, operations, elements, and/or components, but do not preclude the presence or addition of one or more other features, integers, steps, operations, elements, components, and/or groups thereof.
It will be understood that when an element such as a layer, region or substrate is referred to as being “on” or extending “onto” another element, it can be directly on or extend directly onto the other element or intervening elements may also be present. In contrast, when an element is referred to as being “directly on” or extending “directly onto” another element, there are no intervening elements present. It will also be understood that when an element is referred to as being “connected” or “coupled” to another element, it can be directly connected or coupled to the other element or intervening elements may be present. In contrast, when an element is referred to as being “directly connected” or “directly coupled” to another element, there are no intervening elements present. Like numbers refer to like elements throughout the specification.
It will be understood that, although the terms first, second, etc. may be used herein to describe various elements, components, regions, layers and/or sections, these elements, components, regions, layers and/or sections should not be limited by these terms. These terms are only used to distinguish one element, component, region, layer or section from another region, layer or section. Thus, a first element, component, region, layer or section discussed below could be termed a second element, component, region, layer or section without departing from the teachings of the present invention.
Furthermore, relative terms, such as “lower” or “bottom” and “upper” or “top,” may be used herein to describe one element's relationship to another elements as illustrated in the figures. It will be understood that relative terms are intended to encompass different orientations of the device in addition to the orientation depicted in the Figures. For example, if the device in the figures is turned over, elements described as being on the “lower” side of other elements would then be oriented on “upper” sides of the other elements. The exemplary term “lower”, can therefore, encompasses both an orientation of “lower” and “upper,” depending of the particular orientation of the figure. Similarly, if the device in one of the figures is turned over, elements described as “below” or “beneath” other elements would then be oriented “above” the other elements. The exemplary terms “below” or “beneath” can, therefore, encompass both an orientation of above and below.
Embodiments of the present invention are described herein with reference to cross-section (and/or plan view) illustrations that are schematic illustrations of idealized embodiments of the present invention. As such, variations from the shapes of the illustrations as a result, for example, of manufacturing techniques and/or tolerances, are to be expected. Thus, embodiments of the present invention should not be construed as limited to the particular shapes of regions illustrated herein but are to include deviations in shapes that result, for example, from manufacturing. For example, an etched region illustrated or described as a rectangle will, typically, have rounded or curved features. Thus, the regions illustrated in the figures are schematic in nature and their shapes are not intended to illustrate the precise shape of a region of a device and are not intended to limit the scope of the present invention.
Unless otherwise defined, all terms (including technical and scientific terms) used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this invention belongs. It will be further understood that terms, such as those defined in commonly used dictionaries, should be interpreted as having a meaning that is consistent with their meaning in the context of the relevant art and will not be interpreted in an idealized or overly formal sense unless expressly so defined herein. It will also be appreciated by those of skill in the art that references to a structure or feature that is disposed “adjacent” another feature may have portions that overlap or underlie the adjacent feature.
Referring to FIGS. 5A , 5 B, and 5 C, in some embodiments of the present invention, an active region vertically extends from a substrate and a device isolation layer 56 surrounds the active region. The active region includes a unit double layer, which includes a silicon-germanium pattern 52 p and a silicon pattern 54 p . A gate electrode 64 crosses over the active region. Portions of the active region at both sides of the gate electrode 64 include a stacked structure of the germanium pattern 52 p and the silicon pattern 54 p . The active region portion overlapped with the gate electrode 64 has a structure where the silicon pattern 54 p is disposed over a hollow in which the germanium pattern 52 p is removed. The gate electrode 64 extends along sidewalls of the silicon pattern 54 p to fill in the hollow, that is, the gate electrode 64 surrounds the silicon pattern 54 p . A source region 54 s and the drain region 54 d are formed in the silicon pattern 54 p on respective sides of the gate electrode 64 . Sidewall spacers 66 may be formed on sidewalls of the gate electrode 64 . The source and drain regions 54 s and 54 d may have a lightly doped drain (LDD) or a deeply doped drain (DDD) structure. A channel width is determined according to a height of the silicon pattern 54 p . A gate insulating layer 62 is interposed between the gate electrode 64 and the silicon pattern 54 p . The silicon-germanium pattern 52 p is doped before forming the source and drain regions 54 a and 54 d . The silicon-germanium pattern 52 p has a dopant concentration different from the source and drain regions 54 s and 54 d . A top surface of the device isolation layer 56 may be recessed in order that the source and drain regions 54 s and 54 d are completely exposed.
FIGS. 6A-11A are plan views of fabrication products illustrating exemplary operations for fabricating the transistor of FIGS. 5A-5C . FIGS. 6B-11B are cross-sectional views taken along line I-I′ of FIGS. 6A-11A , and FIGS. 6C-11C are cross-sectional views taken along line II-II′ of FIGS. 6A-11A . Referring to FIGS. 6A , 6 B, and 6 C, a silicon-germanium layer 52 and a silicon layer 54 are sequentially formed. The silicon-germanium layer 52 and the silicon layer 54 may be formed using, for example, an epitaxial growth method. A channel width of a transistor depends on the thickness of the silicon layer 54 . The substrate 50 may be, for example, a silicon-on-insulator (SOI) substrate, a germanium-on-insulator (GeOI) substrate, or a silicon-germanium-on-insulator (SiGeOI) substrate. If the uppermost layer is formed of silicon-germanium, the silicon-germanium layer 52 may be omitted.
Referring to FIGS. 7A , 7 B, and 7 C, the silicon layer 54 , the silicon-germanium layer 52 , and a part of the substrate 50 are etched to form a trench, as well as a fin-shaped active region which includes a stacked structure of a silicon-germanium layer 52 p and a silicon pattern 54 p . A device isolation layer 56 is formed, filling in a peripheral portion of the active region and the trench. The active region may be formed using a conventional trench formation process.
Referring to FIGS. 8A , 8 B, and 8 C, a dummy gate pattern 58 that crosses over the active region is formed. Ions are implanted using the dummy gate pattern 58 as an ion implantation mask. The silicon-germanium pattern 52 p is doped to set a projection range of ions into the silicon-germanium pattern 52 p . Silicon-germanium under the dummy gate pattern 58 is not doped.
Referring to FIGS. 9A , 9 B, and 9 C, a sacrificial layer is formed on the substrate and then recessed to expose the dummy gate pattern 58 , which is removed to form a sacrificial pattern 59 having an opening 60 that crosses over the active region. The opening corresponds to a location where a gate electrode will be subsequently formed. A portion of the device isolation layer 56 exposed at the opening 60 is etched to expose sidewalls of the active region, including sidewalls of the silicon-germanium pattern 52 p . The silicon-germanium pattern 52 p exposed in the opening 60 is etched to form a hollow 52 h . Silicon-germanium is selectively removed using an etch ratio difference according to a doping concentration of silicon-germanium, thus suppressing lateral etching and providing a directional (anisotropic) etching effect.
Referring to FIGS. 10A , 10 B, and 10 C, a gate oxide layer is conformally formed on a surface of the silicon pattern 54 p exposed in the opening 60 . A conductive layer is formed on the substrate. The conductive layer may include, for example, amorphous or polysilicon, polysilicon germanium and/or metal materials. The conductive layer fills in the hollow 52 h . For example, silicon or silicon-germanium may be formed in the hollow and covering sidewalls of the silicon pattern 54 p using a chemical vapor deposition method. The conductive layer is removed using a CMP process or an etch-back process until the sacrificial layer is exposed and a gate electrode 64 is formed.
In a conventional process, there may be a great difference between the width of the gate electrode in the hollow and the width of the gate electrode over the silicon layer due to an isotropic etch of silicon-germanium. Generally, the greater the width of the active region, the greater the difference is. In accordance with certain embodiments of the present invention, because silicon-germanium is anisotropically removed using an etch ratio difference created by a doping concentration, this difference can be reduced.
Referring to FIGS. 11A , 11 B, and 11 C, the sacrificial pattern 59 is removed to expose sidewalls of the gate electrode 64 , the active region, and the device isolation layer. The device isolation layer 56 is recessed to expose sidewalls of the active region such that sidewalls of the silicon pattern 54 p surrounded by the gate electrode 64 are exposed. Because the silicon-germanium pattern 52 p does not influence an operation of the transistor, it is generally not important for the silicon-germanium pattern 52 p to be exposed.
Impurities are implanted into the silicon pattern 54 p at both sides of the gate electrode 64 to form the source/drain regions 54 s and 54 d that are shown in FIGS. 5A , 5 B, and 5 C. In addition, sidewall spacers 66 may be formed on sidewalls of the gate electrode 64 . In a gate all around type transistor, a short channel effect may occur. However, in a transistor having a fully depleted channel, a short channel effect may be prevented. Accordingly, a drain with LDD structure or DDD structure may be formed. Before or after forming the sidewall spacers 66 , the drain with LDD structure or DDD structure may be formed.
FIG. 12A is a plan view of a transistor according to second embodiments of the present invention. FIG. 12B is a cross-sectional view taken along line III-III′ of FIG. 12A , and FIG. 12C is a cross-sectional view taken along line IV-IV′ of FIG. 12A . Referring to FIGS. 12A , 12 B, and 12 C, an active region vertically extends from a substrate and a device isolation layer surrounds the active region. The active region includes a unit double layer included of a silicon-germanium pattern 152 p and a silicon pattern 154 p . A gate electrode 164 crosses over the active region. Portions of the active region on respective sides of the gate electrode 164 include a stack of the silicon-germanium pattern 152 p and silicon pattern 154 p . A portion of the active region overlapped with the gate electrode 164 has a structure in which respective silicon patterns 154 p are adjacent hollows where the germanium pattern 152 p is removed. The gate electrode 164 extends along sidewalls of the silicon pattern 154 p to fill in the hollows, such that the gate electrode 164 surrounds the silicon pattern 154 p . Source/drain regions 154 a and 154 d are formed in the silicon pattern 154 p at respective sides of the gate electrode 164 . Sidewall spacers 166 may be formed at sidewalls of the gate electrode 164 . The source/drain regions 154 s and 154 d may have an LDD structure or a DDD structure. A channel width is determined by a height of the silicon pattern 154 p . A gate insulating layer 162 is interposed between the gate electrode 164 and the silicon pattern 154 p . The silicon-germanium pattern 152 p is doped before forming the source/drain regions 154 s and 154 d . The silicon-germanium pattern 152 p is doped with a concentration different from the source/drain regions 154 s and 154 d.
FIGS. 13A-18A are plan views of fabrication products illustrating exemplary operations for fabricating the transistor of FIGS. 12A-12C . FIGS. 13B-8B are cross-sectional views taken along line III-III′ of FIGS. 13A-18A , and FIGS. 13C-18C are cross-sectional views taken along line IV-IV′ of FIG. 13A-18A . Referring to FIGS. 13A , 13 B, and 13 C, a plurality of unit double layers, which include a stack of a silicon-germanium layer 152 and a silicon layer 154 , are formed on a substrate 150 . The silicon-germanium layer 152 and the silicon layer 154 may be formed using an epitaxial growth method. The channel width of a transistor depends on the thickness of the silicon layer 154 . The substrate 150 may be, for example, a silicon-on-insulator (SOI) substrate, a germanium-on-insulator (GeOI) substrate, or a silicon-germanium-on-insulator (SiGeOI) substrate. If the uppermost layer of the substrate 150 is silicon-germanium, the lower silicon-germanium layer 152 may be omitted.
Referring to FIGS. 14A , 14 B, and 14 C, the stacked unit double layer and a part of the substrate are etched to form a trench and at the same time, to form a plurality of silicon-germanium patterns 152 p and a fin-shaped active region in which a plurality of silicon patterns 154 p are stacked. A device isolation layer 156 is formed at a peripheral portion of the active region. The active region may be formed using a conventional trench formation process.
Referring to FIGS. 15A , 15 B, and 15 C, a dummy gate pattern 158 that crosses over the active region is formed. Ions are implanted into the active region using the dummy gate pattern 158 as an ion implantation mask. The silicon-germanium pattern 152 p is doped in setting a projection range of ions to the germanium pattern 152 p . A plurality of ion implantation processes may be sequentially performed to set a projection range into the silicon germanium pattern 152 p in each layer. The silicon-germanium pattern under the dummy gate pattern 158 is not doped.
Referring to FIGS. 16A , 16 B, and 16 C, a sacrificial layer is formed on the substrate. The sacrificial layer is recessed to expose the dummy gate pattern 158 , and the dummy gate pattern is removed to form a sacrificial pattern 159 having an opening 160 crossing over the active region. The opening 160 is located where a gate electrode is subsequently formed. The device isolation layer 156 exposed at the opening 160 is etched to expose sidewalls of the active region, that is, sidewalls of the silicon pattern 154 p and the silicon-germanium pattern 152 p . The silicon-germanium patterns 152 p exposed at the opening 160 are etched to form a plurality of hollows 152 h.
Referring to FIGS. 17A , 17 B, and 17 C, a gate oxide layer is conformally formed on the silicon patterns 154 p exposed in the opening 160 . A conductive layer is formed on the substrate, filling the hollows 152 h . The conductive layer may be amorphous silicon or polysilicon, polysilicon germanium or metal materials. The conductive layer is removed using CMP or etch-back process until the sacrificial layer is exposed and a gate electrode 164 is formed.
Referring to FIGS. 18A , 18 B, and 18 C, the sacrificial pattern 159 is removed to expose sidewalls of the gate electrode 164 , the active region, and the device isolation layer. The device isolation layer is recessed to expose sidewalls of the active region and to expose the sidewalls of the silicon pattern 154 p covered with the gate electrode 164 . Because the silicon-germanium pattern 52 p does not influence operation of the transistor, it generally is not important whether or not the silicon-germanium pattern 52 p is exposed.
Impurities are implanted into the silicon pattern 154 p at respective sides of the gate electrode 164 to form the source/drain regions 154 s and 154 d shown in FIGS. 12A , 12 B, and 12 C. In addition, sidewall spacers 166 may be formed on sidewalls of the gate electrode 164 . In a gate all around type transistor, a short channel effect may occur. In a transistor having a fully depleted channel, a short channel effect may be prevented. Accordingly, a drain with LDD structure or DDD structure may be formed. Before/after forming the sidewall spacer 66 , the drain with LDD structure or DDD structure may be formed.
FIG. 19A is a plan view illustrating a transistor according to third embodiments of the present invention. FIG. 19B is a cross-sectional view taken along line V-V′ of FIG. 19A , and FIG. 19C is a cross-sectional view taken along line VI-VI′ of FIG. 19A . The transistor includes a device isolation layer 256 formed on a substrate 150 . The device isolation layer 256 defines an active region. The active region includes a unit double layer including a silicon-germanium pattern 252 p and a silicon pattern 254 p . Portions of the active region at respective sides of the gate electrode include of a stacked structure of the silicon-germanium pattern 252 p and the silicon pattern 254 p . A portion of the active region overlapped with the gate electrode 264 has a structure in which the silicon pattern 254 p is disposed on a region where the silicon-germanium pattern 252 p is removed. The gate electrode 264 extends along sidewalls of the silicon pattern 254 p to be aligned to an insulating pattern 263 filling the region underlying the silicon pattern 254 p , that is, the silicon pattern 254 p is surrounded by the gate electrode 264 and the insulating pattern 263 . Source/drain regions 254 s and 254 d are formed in the silicon pattern 254 p at respective sides of the gate electrode 264 . Sidewall spacers 266 may be formed on sidewalls of the gate electrode 264 . The source/drain regions 254 s and 254 d may have an LDD structure or a DDD structure. A channel width is determined according to a height of the silicon pattern 254 p . A gate insulating layer 262 is interposed between the gate electrode 264 and the silicon pattern 254 p . The silicon-germanium pattern 252 p is doped before forming the source/drain regions 254 s and 254 d . The silicon-germanium pattern 252 p is doped with a concentration different from the source/drain regions 254 s and 254 d . In accordance with these embodiments, an insulating pattern is formed between the source and drain regions of the planar transistor. The insulating pattern is formed under a channel of a transistor in which a punch-through could occur, thus reducing or preventing punch-through.
FIGS. 20A-25A are cross-sectional views of fabrication products illustrating exemplary operation for fabricating the transistor of FIGS. 19A-19C . FIGS. 20B-25B are cross-sectional views taken along line V-V′ of FIGS. 20A-25A , and FIGS. 20C-25C are cross-sectional views taken along line VI-VI′ of FIGS. 20A-25A .
Referring to FIGS. 20A , 20 B, and 20 C, a silicon-germanium layer 252 and a silicon layer 254 are sequentially formed on a substrate 250 . The silicon-germanium layer 252 and the silicon layer 254 may be formed using an epitaxial growth method. A channel width of the transistor to be formed depends on the thickness of the silicon layer 254 . The substrate 250 may be, for example, a silicon-on-insulator (SOI) substrate, a germanium-on-insulator (GeOI) substrate, or a silicon-germanium-on-insulator (SiGeOI) substrate. If the uppermost layer of the substrate 250 is silicon-germanium, the silicon-germanium layer 252 may be omitted.
Referring to FIGS. 21A , 21 B, and 21 C, parts of the silicon layer 254 , the silicon-germanium layer 252 and the substrate are etched to form a trench that defines an active region on which a silicon-germanium pattern 252 p and the silicon pattern 254 p are stacked. A device isolation 256 layer is formed in the trench. The active region may be formed by a conventional trench formation process.
Referring to FIGS. 22A , 22 B, and 22 C, a dummy gate pattern 258 that crosses over the active region is formed. Ions are implanted into the active region using the dummy gate pattern 258 as an ion implantation mask. The silicon-germanium pattern 252 p is doped to setting a projection range of ions to the silicon-germanium pattern 252 p . Silicon-germanium under the dummy gate pattern 258 is not doped.
Referring to FIGS. 23A , 23 B, and 23 C, a sacrificial layer is formed on the substrate. The sacrificial layer is recessed to expose the dummy gate pattern 258 , which is removed to form a sacrificial pattern 259 having an opening 260 crossing over the active region. The opening 260 is located where a gate electrode is to be formed. The device isolation layer 256 exposed at the opening 260 is etched to expose sidewalls of the active region, that is, sidewalls of the silicon pattern 254 p and the silicon-germanium pattern 252 p . The silicon-germanium pattern 252 p exposed in the opening 260 is etched to form a hollow 252 h.
Referring to FIGS. 24A , 24 B, and 24 C, a buffer oxide layer 261 is conformally formed on the exposed silicon pattern 254 p . An insulating material is formed in the opening 260 then it is recessed to expose a top surface of the active region. As a result, an insulating pattern 263 is formed. The insulating pattern 263 fills in the hollow 252 h . The sacrificial pattern 259 is removed to expose the active region and the device isolation layer. Referring to FIGS. 25A , 25 B, and 25 C, a gate insulating layer 262 is formed on the active region. A gate electrode 264 that crosses over the active region is formed. The gate electrode 264 is disposed on the insulating pattern 263 .
Impurities are implanted into the silicon pattern 254 p at respective sides of the gate electrode 264 to form the source region 2254 s and the drain region 254 d shown in FIGS. 19A , 19 B, and 19 C. In addition, sidewall spacers 266 may be formed on sidewalls of the gate electrode 264 . Before or after forming the sidewall spacers 266 , ions may be implanted to form a drain with LDD structure or DDD structure.
FIG. 26A is a plan view of a transistor according to fourth embodiments of the present invention. FIG. 26B is a cross-sectional view taken along line VII-VII′ of FIG. 26A . FIG. 26C is a cross-sectional view taken along line VIII-VIII′ of FIG. 26A .
Referring to FIGS. 26A , 26 B, and 26 C, a planar transistor includes an active region vertically extending from a substrate 360 . The active region includes a unit double layer, which includes a stacked structure of a silicon-germanium pattern 352 p and the silicon pattern 354 p . A gate electrode 364 crosses over the active region. Portions of the active region on respective sides of the gate electrode 364 include a stacked structure of the silicon-germanium pattern 352 p and the silicon pattern 354 p . A portion of the active region overlapped with the gate electrode 364 has a structure in which the silicon pattern 354 p is disposed on a region where the silicon-germanium pattern 352 p is removed. The gate electrode 364 extends along sidewalls of the silicon pattern 354 p to be aligned with an insulating pattern 363 filled in the region underlying the silicon pattern 354 p . The gate electrode 364 covers a top surface and sidewalls of the silicon pattern 354 p and the insulating pattern 363 fills in the region underlying the silicon pattern 354 p , i.e., the silicon pattern 354 p is surrounded by the gate electrode 364 and the insulating pattern 363 . Source/drain regions 354 s and 354 d are formed on respective sides of the gate electrode 364 . Sidewall spacers 366 may be formed on sidewalls of the gate electrode 364 . The source/drain regions 354 s and 354 d may have an LDD structure or a DDD structure. A channel width is determined by the height of the silicon pattern 354 p . A gate insulating layer 362 is interposed between the gate electrode 364 and the silicon pattern 354 p . The silicon-germanium pattern 352 p is doped before forming the source and drain regions 354 s and 354 d , with a concentration different from the source/drain regions 354 s and 354 d . In accordance with these embodiments, an insulating pattern is capable of preventing a punch-through between the source region and the drain region under a channel region that is controlled by a gate electrode.
FIGS. 27A-32A are plan views of fabrication products illustrating exemplary operations for fabricating the transistor of FIGS. 26A-26C . FIGS. 27B-32B are cross-sectional views taken along line VII-VII′ of FIGS. 27A to 32A , and FIGS. 27C-32C are cross-sectional views taken along line VIII-VIII′ of FIGS. 27A to 32A .
Referring to FIGS. 27A , 27 B, and 27 C, a silicon-germanium layer 352 and a silicon layer 354 are sequentially formed on a substrate 350 . The silicon-germanium layer 352 and the silicon layer 354 may be formed using an epitaxial growth method. A channel width of the transistor to be formed depends on the thickness of the silicon layer 354 . The substrate 350 may be, for example, a silicon-on-insulator (SOI) substrate, a germanium-on-insulator (GeOI) substrate, or a silicon-germanium-on-insulator (SiGeOI) substrate. If the uppermost layer of the substrate 350 is silicon-germanium, the silicon-germanium layer 352 may be omitted.
Referring to FIGS. 28A , 28 B, and 28 C, parts of the silicon layer 354 , the silicon-germanium layer 352 and the substrate 350 are etched to form a trench that defines an active region with a fin-shaped stack of a silicon-germanium pattern 352 p and a silicon pattern 354 p . A device isolation layer 356 is formed in the trench. The active region may be formed using a conventional trench formation process.
Referring to FIGS. 29A , 29 B, and 29 C, a dummy gate pattern 358 that crosses over the active region is formed. Ions are implanted into the active regions using the dummy gate pattern 358 as an ion implantation mask. The silicon-germanium pattern 352 p is doped to set a projection range of ions to the silicon-germanium pattern 352 p . Silicon-germanium under the dummy gate pattern 358 is not doped.
Referring to FIGS. 30A , 30 B, and 30 C, a sacrificial layer is formed on the substrate. The sacrificial layer is recessed to expose the dummy gate pattern 358 , which is removed to form a sacrificial pattern 359 having an opening 360 crossing over the active region. The opening is located where a gate electrode is to be formed. A device isolation layer 356 exposed at the opening 360 is etched to expose sidewalls of the active region, including sidewalls of the silicon pattern 354 p and the silicon-germanium pattern 352 p . The silicon-germanium pattern 352 p exposed in the opening 360 is etched to form a hollow 352 h.
Referring to FIGS. 31A , 31 B, and 31 C, a buffer oxide layer is conformally formed on the exposed silicon pattern 354 p . An insulating layer is formed on the substrate, filling the hollow 352 h . The insulating layer is removed using CMP or etch-back until the sacrificial layer is exposed. The insulating layer is recessed to expose sidewalls of the silicon pattern 354 p . As a result, an insulating pattern 363 is formed.
Referring to FIGS. 32A , 32 B, and 32 C, a buffer insulating layer on the exposed silicon pattern 354 p is removed, and then a gate insulating layer 362 is formed. A conductive layer is formed and then recessed to form a gate electrode 364 . The sacrificial pattern 359 is removed to expose sidewalls of the gate electrode 364 , the active region, and the device isolation layer. At this time, the sidewalls of the silicon pattern 354 p covered with the gate electrode 364 are exposed. Because the silicon-germanium pattern does not influence operation of the transistor, whether it is exposed or not is generally not important.
Impurities are implanted into the silicon pattern 354 p at respective sides of the gate electrode 364 to form the source/drain regions 354 s and 354 d shown in FIGS. 26A , 26 B, and 26 C. Sidewall spacers 366 may be formed on sidewalls of the gate electrode 364 . Before or after forming the sidewall spacer 366 , ions may be implanted to form a drain with LDD structure or DDD structure.
In some embodiments of the present invention, silicon-germanium is doped using an oblique ion implantation method, which can reduce the width of an un-doped region can be reduced. Additionally, the width of the un-doped region can be increased by doping after forming a dummy spacer at sidewalls of a dummy gate pattern. This means that the width of a subsequently formed hollow adjacent the channel can be optimized. The dummy spacer may be removed after doping. Additional processes may be performed before forming the gate oxide layer. One is a sacrificial oxidation process for rounding an edge portion of the hollow. The other is a process for recessing a surface of a silicon pattern defining the hollow.
In some embodiments of the present invention, silicon-germ anium is selectively etched using an etch ratio difference between doped silicon-germanium and an un-doped silicon-germanium so that it is possible to form a hollow for formation of a gate electrode or insulating region with a narrow width. Therefore, it is possible to reduce a variation in channel length in a gate all around type transistor.
Many alterations and modifications may be made by those having ordinary skill in the art, given the benefit of the present disclosure, without departing from the spirit and scope of the invention. Therefore, it must be understood that the illustrated embodiments have been set forth only for the purposes of example, and that it should not be taken as limiting the invention as defined by the following claims. The following claims are, therefore, to be read to include not only the combination of elements which are literally set forth but all equivalent elements for performing substantially the same function in substantially the same way to obtain substantially the same result. The claims are thus to be understood to include what is specifically illustrated and described above and what is conceptually equivalent. | An elongate stacked semiconductor structure is formed on a substrate. The stacked semiconductor structure includes a second semiconductor material region disposed on a first semiconductor material region. The first semiconductor material region is selectively doped to produce spaced-apart impurity-doped first semiconductor material regions and a lower dopant concentration first semiconductor material region therebetween. Etching exposes a portion of the second semiconductor material region between the impurity-doped first semiconductor material regions. The etching removes at least a portion of the lower dopant concentration first semiconductor material region to form a hollow between the substrate and the portion of the second semiconductor material region between the impurity-doped first semiconductor material regions. An insulation layer that surrounds the exposed portion of the second semiconductor material region between the impurity-doped first semiconductor material regions is formed. The hollow may be filled with a gate electrode that completely surrounds the exposed portion of the second semiconductor material region, or the gate electrode may partially surround the exposed portion of the second semiconductor material region and an insulation region may be formed in the hollow. | 7 |
This application is a continuation-in-part of application U.S. Ser. No. 08/241,760, filed May 12, 1994, now U.S. Pat. No. 5,403,046.
BACKGROUND OF THE INVENTION
This invention relates to devices of the class used for joining fluid carrying conduits. More specifically, the invention is a coupler used to connect elastomeric irrigation tubing or hoses, meaning either the connecting of two lengths of tubing or hose to each other, or the connecting of one tube or hose to a threaded plumbing fixture.
Underground lawn sprinkling systems and other underground irrigation systems generally are comprised of varying lengths of polyethylene hose or tube. Although polyvinyl chloride (PVC) tube is a widely used material for interior plumbing systems, PVC is not suitable for such underground systems in all climates, as PVC is rigid and cannot accomodate changes in dimension caused by freeze-thaw cycles. The PVC pipe system must be drained of all water every cold season by draining or blowing, in order to prevent rupture by the expansion of frozen water. Polyethylene can, however, accomodate such temperature changes, so it has become the predominant material in such underground systems. Polyethylene poses a problem for installers and repairers, though. After underground installation, whenever it is necessary to join two lengths of polyethylene tube or hose, a coupling must be used, of the type that has two nipples to fit into each end of the hoses to be joined. To install the coupling, the installer very frequently has to lift and gently bend one end of hose, in order to shorten that length of hose enough to fit over the end of a nipple and then be pushed over the length of the nipple. Even if due care is exercised in the installation, while so bending the hose it often kinks, which substantially weakens the integrity of polyethylene hose. This in turn necessitates expensive and time consuming hose replacement and further repair.
Therefore, there is a need for a coupler that can be installed in such polyethylene irrigation systems without the need to bend up one of the hose sections to be joined and run the risk of kinking the section. It is the primary object of the present invention to meet this need by providing a coupling that can be dimensionally shortened to fit into a gap between two sections of hose to be joined, and then be dimensionally lengthened so that each nipple can be thrust into each of the hose ends. The present invention accomplishes this by the use of a three component assembly, namely an outer or female nippled component, an inner or male nippled component and a locking cap. The inner component can slide with respect to the outer component, thus shortening or lengthening the complete coupling. Thus, the assembled coupling can be placed in a cut gap between two lengths of hose, one nipple can be inserted into the first end of hose and the coupling can be pulled out or expanded so that the second nipple can be inserted into the second hose end. By being able to expand in length, the coupling does away with the need to lift and bend one end of hose, eliminating that as a source of potential hose kinks.
Another object of the invention is to be able to securely affix a lock cap without the need for adhesives. This has been accomplished by the use of the technique of untrasonic welding. This feature eliminates the need for adhesives, which are toxic, expensive and messy to handle.
SUMMARY OF THE INVENTION
The invention is a coupler for joining elastomeric hoses, comprising: firstly, an outer tubular coupling member having a longitudinal axis and distal and proximal ends; having a nipple at the distal end for sealably seating within a predetermined length of a first elastomeric hose to be joined; with at least a portion of the internal diameter of the outer tubular coupling member being of a suitable dimension to telescopically receive an inner tubular coupling member; secondly, an inner tubular coupling member having a longitudinal axis and distal and proximal ends; having a nipple at the distal end for sealably seating within a second elastomeric hose to be joined to said first elastomeric hose; at least one annular groove at the proximal end for receiving a ring shaped distortable sealing member; and a plurality of projections on the outer surface of said inner tubular coupling member, the projections circumferentially arrayed on said inner tubular coupling member; the proximal end of said inner tubular coupling member fitting telescopically inside of the proximal end of said outer tubular coupling member; and thirdly a substantially tubular locking cap member having a longitudinal axis and distal and proximal ends; having an internal diameter of a suitable dimension to telescopically fit over said inner tubular coupling member such that said locking cap, when fitted over said inner tubular coupling member comes into juxtaposed contact with said outer tubular coupling member after assembly of the cap, the inner tubular coupling member and the outer tubular coupling member; said locking cap additionally having a plurality of substantially longitudinal grooves in the locking cap's inner surface of sufficient dimension to slideably receive said plurality of projections on said inner tubular coupling member to prevent rotational movement of the inner tubular coupling member with respect to the cap, yet allowing such rotational movement when, after assembly of the cap, the inner tubular coupling member and the outer tubular coupling member, at least a portion of the inner tubular coupling member is pulled along a substantially longitudinal axis for a sufficient distance such that said projections are pulled past the end of said cap, thereby allowing such rotational movement.
An alternative preferred embodiment of the invention, that can either be used to join one elastomeric hose or tube to another or to join an elastomeric hose or tube to a plumbing fixture comprises firstly an outer tubular coupling member having a longitudinal axis and distal and proximal ends; having a nipple at the distal end for sealably seating within a predetermined length of a first elastomeric hose to be joined, said nipple beating on its outer surface a plurality of saw-toothed parallel threads; a flange against which an end portion of said elastomeric hose abuts; with at least a portion of the internal diameter of the outer tubular coupling member being of a suitable dimension to telescopically receive an inner tubular coupling member; and an internal surface flange against which said inner tubular coupling member abuts; secondly an inner tubular coupling member having a longitudinal axis and distal and proximal ends; having a nipple at the distal end for sealably seating within a predetermined length of a second elastomeric hose to be joined to the first elastomeric hose, said nipple bearing on its outer surface a plurality of saw-toothed parallel threads, or for sealably seating within a threaded fluid-carrying fixture, in which case said nipple bears on its outer surface a plurality of helical threads; at least one annular circumferential groove at the proximal end for receiving a ring shaped distortable sealing member; and a plurality of lugs on the outer surface of said inner tubular coupling member, the lugs circumferentially arrayed on said inner tubular coupling member; the proximal end of said inner tubular coupling member fining telescopically inside of the proximal end of said outer tubular coupling member; and thirdly a substantially tubular locking cap member having a longitudinal axis and distal and proximal ends; having an internal diameter of a suitable dimension to telescopically fit over said inner tubular coupling member such that said locking cap, when fitted over said inner tubular coupling member comes into juxtaposed contact with said outer tubular coupling member after assembly of the cap, the inner tubular coupling member and the outer tubular coupling member; said locking cap additionally having a plurality of substantially longitudinal grooves in the locking cap's inner surface of sufficient dimension to slideably receive said plurality of lugs on said inner tubular coupling member to prevent rotational movement of the inner tubular coupling member with respect to the cap, yet allowing such rotational movement when, after assembly of the cap, the inner tubular coupling member and the outer tubular coupling member, at least a portion of the inner tubular coupling member is pulled along a substantially longitudinal axis for a sufficient distance such that said projections are pulled past the end of said cap, thereby allowing such rotational movement.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a longitudinal central cross section view of two lengths of hose connected by a preferred embodiment of the invention, not to scale.
FIG. 2 is a longitudinal cross section in side view, showing the outer tubular coupling member, not to scale.
FIG. 3 is a longitudinal cross section view showing the outer tubular coupling member, not to scale.
FIG. 4 is a longitudinal side view of the locking cap with its sealing flange, not to scale.
FIG. 5 is a cross section view of the locking cap, taken through the thicker diameter of the cap, showing the grooves for receiving the external lugs of the inner coupling member, not to scale.
FIG. 6 is a perspective view of the locking cap, featuring the slots in the cap for receiving the lugs on the inner coupling member, not to scale.
FIG. 7 is a longitudinal cross section view showing the inner coupling member, not to scale.
FIG. 8 is a side view showing the inner coupling member and featuring external lugs on the surface, not to scale.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
At FIG. 1 there is shown in cross section the assembled coupler of the present invention, with hoses or tubes 2 shown fitted over the nipples 11 and 31. It can be seen that the entire coupling assembly is made up of three components: the outer tubular coupling member 3, which can be seen to be a cylinder or female type coupling member; the inner tubular coupling member 5, which can be seen to be a piston or male type coupling member; and the end plug locking cap member 7.
The outer tubular coupling 3 is shown in FIGS. 2 and 3, where it can be seen to be a substantially tubular component. The nipple 11 preferably bears a plurality of circumferential parallel threads 9 that tend to grip into the relatively soft material of an elastomeric hose. Most preferably, the threads 9 are a sawtooth pattern in profile, that permits ready fitting of the end of a hose over the nipple up to the hose abutment flange 17, but resists pulling the same hose end off of the nipple 11. The outside diameter of the nipple 11 is a slight degree larger than the inside diameter of the hose to be connected, and outside diameters of the nipple 11 are molded in sizes that comport to industry standards for hoses. In a more preferred embodiment of the invention, the outer barrel 14 of the outer tubular coupling 3 has molded or otherwise fixably mounted thereon a plurality of ribs 15 that run substantially in a longitudinal axis parallel to the longitudinal axis of the coupling assembly. The ribs 15 are an aid to the installer or repairer to get a better grip on the outer tubular coupling 3, which, since it is preferably molded plastic, will be slippery if wet. In an alternative embodiment of the invention the outer barrel 14 has molded thereon a plurality of nubs or other raised surface shapes, or has molded thereon a roughened surface to increase friction.
In a most preferred embodiment, the proximal end of the outer tubular coupling 3 fits over a portion of the barrel of the end cap 7, as shown in FIG. 1, thus helping form a seal. There are a large variety of ways that outer coupling 3 can come into such juxtaposed contact with the end cap 7, and the invention in not to be limited to the particular configuration depicted in FIG. 1. In particular, there is no critical length of cap 7's barrel, or the rabbet in the interior of outer coupling member 3 that accomodates any portion of the length of the cap's barrel.
The inner tubular coupling 5 is shown in FIGS. 1 and 7, where it can be seen to be a substantially tubular component. Its nipple 31, like the nipple 11 on the outer coupling 3, preferably bears on its distal end a plurality of circumferential threads 9 that most preferably are a sawtooth pattern in profile. In an important alternative embodiment of the invention, the threads 9 on the distal end of the inner tubular coupling member 5 can be helical instead of parallel, so that the coupling can be screwed into a plumbing fixture having a suitably threaded bore.
The inner coupling has, at its proximal end, at least one annular groove 35 (FIG. 7) for receiving a ring shaped distortable sealing member, which most preferably is an O-ring 33 (FIG. 1) made of a suitable rubber or plastic compound. Depending on the application in question, more than one annular groove and O-ring can be fabricated on the inner coupling. The inner tubular coupling member 5 can be pushed into the outer tubular coupling member 3 until the abutment flange 37 is reached.
The inner tubular coupling member 5 has a plurality of projections 39 circumferentially arrayed on its outer surface, as shown in FIG. 8. These are preferably molded lugs. Most preferably, there are three lugs that are substantially cuboidal in shape and are uniformly arrayed. The lugs will most advantageously be formed relatively close to the threads 9.
The cap member 7 is shown in FIGS. 1, 4, 5 and 6. The cap is substantially tubular, and features an abutment flange that serves to form a sealing abutment for both the end of an elastomeric hose or tube on one side of the flange, and the proximal end of the outer coupling member 3 at the other side of the flange.
The cap 7 additionally has a sufficient number of grooves 55 formed therein so as to allow the projections 39 to slideably move through the grooves 55 when the inner coupling member 5 is pulled or pushed through the cap 7. Most preferably, these grooves 55 open to the distal end of the cap 7, as shown in FIG. 6, but not to the proximal end.
In the most preferred method of operation, the cap member 7 is telescopically pushed pan way onto the inner coupling member 5 so that the grooves 55 open towards the threads 9. The grooves slide over the projections 39. The nipple 31 is fitted in a section of hose or tube to be joined, or in the embodiment having helical threads, is screwed into a plumbing fixture threaded bore. Then, the outer coupling member 3 is telescopically fitted onto the proximal end of the inner coupling member 5 and the cap 7 is pushed onto the proximal end of the outer member 3 until stopped or juxtaposed against the complementary surfaces of the outer member 3, positioning the cap in place. The assembled coupler 1 is then lengthened by pulling the outer member 3 away from inner member 5 as nipple 9 is inserted into the second end of hose or tube to be joined. It should be noted that while the projections 39 are engaged in the grooves 55, the cap cannot rotate with respect to the inner member 5. Whenever the inner member 5 is pulled past the end of cap 7, the projections 39 do not engage the grooves 55 and the cap 7 can rotate with respect to the inner member 5. The cap 7 is then fixed permanently in place by the method of ultrasonic welding, which is well known to workers in that art. Ultrasonic welding permanently fixes the cap in place by causing the thermoplastic materials of the component pieces to meld and then cure in an agglomerated whole.
Although by virtue of the use of ultrasonic welding the locking cap can be permanently affixed without the need for adhesives, such adhesives can still be used. The adhesive of choice for the PVC type of coupling is methyl ethyl ketone. There is an alternative embodiment of the invention that does not feature the spring biased tabbed prongs, and it would be entirely appropriate to use adhesive to lock the cap in place. In yet another embodiment of the invention, an annular groove is caused to be formed between the female member abutment flange 47 and the cap abutment flange 21 providing a suitable channel for liquid adhesive to be injected into, allowing the adhesive to run into the contact area between the interior of the cap 7 and the exterior of the female member 3.
The coupling components can most economically be made by injection molding techniques well known to those of ordinary skill in the plastics art. The most preferred material for molding the coupling components is PVC. Although PVC is unsuitable for use as underground conduit for water due to the aforementioned problems with it being unable to accomodate temperature changes, the relatively short length of the coupling in relation to the overall length of the conduit system of which it is a part means that shrinkage and expansion due to temperature changes will be adequately accomodated by the polyethylene hoses, minimizing stress on the coupling.
While the invention has been described and illustrated with reference to certain preparative embodiments thereof, those skilled in the art will appreciate that various changes, modifications and substitutions can be made therein without departing from the spirit and scope of the invention. It is intended, therefore, that the invention be limited only by the scope of the claims which follow, and that such claims be interpreted as broadly as possible. | A coupling device especially adapted for the joining of polyethylene underground irrigation hoses, having a female portion, a male portion and a lock cap, the female portion having a threaded nipple for insertion into a hose end, the male portion likewise having a threaded nipple for insertion into a second hose end and several lugs that fit into grooves in the lock cap, enabling the male portion to be pulled out of the assembly for a limited distance, for ease of fitting into difficult hose coupling situations. The presence of the lugs prevents rotation of the male portion with respect to the cap until the male portion is pulled out of the assembly far enough that the lugs are pulled past the end of the locking cap. | 5 |
BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to mechanical park locking for vehicle transmissions, and more specifically, but not exclusively, to a park lock mechanism for narrow transmissions having tight packaging and weight constraints.
[0002] Park lock devices for automotive vehicle transmissions are notoriously well known as a general proposition. Transmissions have continued to evolve, and park lock devices disposed within such transmissions also need to evolve. For example, a particular transmission for an electric vehicle (EV) is quite narrow as it is positioned between an electric motor on one side and an inverter on the other side. Where many conventional park lock devices are implemented in two planes, a narrow transmission of an electric vehicle prevents implementation of such conventional solutions. Further, many conventional park lock devices include a park lock controller near the parking gear. The narrow transmission having large areas covered by the motor on one side and the inverter on the other limits such conventional location of the park lock controller.
[0003] Mechanical cooperation of the components of such transmissions preferably meet a number of operational goals in addition to provision of a park mode and a not parked mode. These operational goals in some cases are actual requirements and include resistance to park engagement while the vehicle is moving. As soon as the speed of the vehicle falls below the lock speed while park mode is commanded, the park lock device should automatically engage to safely enter into the park mode and stop the vehicle. The transmission should then remain parked until the vehicle is transitioned to the not parked mode. Irrespective of a slope on which the EV is stopped, the transmission should not provide too great of mechanical resistance to mode transition.
[0004] While not necessarily required by the narrowness of the EV transmission, systems on EVs have tight budgets for space and weight. These budget constraints work against a straight-forward implementation of a park lock device for a narrow transmission such as may be contemplated to be used in an EV. What is needed is a system and method for a park lock mechanism for narrow transmissions having tight packaging and weight constraints.
BRIEF SUMMARY OF THE INVENTION
[0005] Disclosed is a system and method for a park lock mechanism for narrow transmissions having tight packaging and weight constraints. A novel architecture reduces part count to implement a robust one-dimensional remotely-actuated self-aligning park lock device in a narrow transmission that is appropriate for use in an electric vehicle or the like.
[0006] The following summary of the invention is provided to facilitate an understanding of some of technical features related to narrow transmission park lock devices, and is not intended to be a full description of the present invention. A full appreciation of the various aspects of the invention can be gained by taking the entire specification, claims, drawings, and abstract as a whole. The present invention is applicable to other transmission systems other than electric passenger vehicles.
[0007] A park lock device of a narrow transmission includes a park gear provided in a transmission case at a rotational axis which rotates together with a wheel axle; a park pawl provided in the transmission case so as to rotate about a pawl shaft coupled to a proximal end of the park pawl, the park pawl having a pawl portion at a distal end which locks the park gear through an engagement therebetween wherein the park pawl further includes a body portion coupling the proximal end to the distal end and a cam contact portion at the distal end opposing the pawl portion; a park rod provided in the transmission case so as to move together with an operation of a controller, the park rod having a cam portion which presses the cam contact portion of the park pawl so as to make the engagement between the pawl portion of the park pawl and the park gear according to the operation of the controller; a park sleeve receiving the cam portion of the park rod and defining a first contact point providing a reactive force to the cam contact portion of the park pawl pressing against the cam portion of the park rod at a second contact point; a pawl torsional spring, coupled to the pawl shaft, biasing a rotation of the park pawl about the pawl shaft towards a disengagement of the park gear and the pawl portion to unlock the park gear; and a pawl stopper provided in the transmission case to limit the rotation of the park pawl by contacting the body portion of the park pawl; wherein motion of the park gear, the park pawl, and the park rod are constrained within a vertical plane of the transmission case.
[0008] A park lock method for a narrow transmission case, the method responsive to a controller to selectively engage a park gear provided for rotation in a plane of the narrow transmission case at a rotational axis which rotates together with a wheel axle, the method including a) moving, within the plane of the narrow transmission case, a park rod together with an operation of the controller remotely disposed from the park gear, the park rod including a cam portion; b) pressing the cam portion against a cam contact portion of a park pawl disposed within the narrow transmission case to engage the park gear when the operation of the controller commands a park mode, the park pawl rotatable within the plane about a pawl shaft disposed at a proximal end of the park pawl with the park pawl including a pawl portion at a distal end that engages the park gear in the park mode wherein the cam contact portion is also disposed at the distal end opposing the pawl portion and interacts with the cam portion within a self-aligning rotatable park sleeve; c) releasing the cam portion from the cam contact portion of the park pawl to disengage the park gear when the operation of the controller commands a not park mode; and d) rotating the park pawl to disengage the pawl portion from the park gear responsive to a disengagement-biasing torsional spring coupled to the pawl shaft after the cam portion has been released from the cam contact portion wherein a self-aligning pawl stopper is rotatably disposed proximate a body portion of the park pawl to limit disengaging rotation of the park pawl with the body portion joining the proximal end to the distal end.
[0009] There are a number of features, benefits, and advantages of the present invention, with implementations of the present invention including reduced stresses and fewer mounting requirements for the park lock device components. Some features include including use of a self-aligning park sleeve that does not experience any net moment under parked load, a bracket simply retains both the park sleeve and pawl stopper within alignment limits, and provides safe operation in a parked mode and a not parked mode.
[0010] Other features, benefits, and advantages of the present invention will be apparent upon a review of the present disclosure, including the specification, drawings, and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The accompanying figures, in which like reference numerals refer to identical or functionally-similar elements throughout the separate views and which are incorporated in and form a part of the specification, further illustrate the present invention and, together with the detailed description of the invention, serve to explain the principles of the present invention.
[0012] FIG. 1 illustrates a side view of a narrow transmission including a park lock device, the park lock device in a “not parked” mode;
[0013] FIG. 2 illustrates a side view of the narrow transmission illustrated in FIG. 1 with the park lock device in a “parked” mode;
[0014] FIG. 3 illustrates a sectional view of a portion of the park lock device of FIG. 1 depicting an interaction of the park rod and the park pawl inside the park sleeve;
[0015] FIG. 4 illustrates a sectional view of a portion of the park lock device of FIG. 2 depicting an interaction of the park rod and the park pawl inside the park sleeve;
[0016] FIG. 5 illustrates a sectional view of a portion of the park lock device detailing a transition between the parked mode and the not parked mode;
[0017] FIG. 6 illustrates a sectional view of a portion of the park lock device detailing an operational mode with a controller in parked position prior to the parking pawl engaging the park gear;
[0018] FIG. 7 illustrates a side view of the park rod;
[0019] FIG. 8 illustrates a top view of the park rod;
[0020] FIG. 9 illustrates a sectional view of a mid-portion of the park rod;
[0021] FIG. 10 illustrates a top view of the park lock device components from FIG. 2 (park mode) isolated from the transmission case;
[0022] FIG. 11 illustrates a side view of the park lock device components of FIG. 10 ;
[0023] FIG. 12 illustrates an end view of the parking sleeve detailing an opening receiving the cam portion of the parking rod; and
[0024] FIG. 13 illustrates an isometric view of the parking sleeve including receipt of the cam portion.
DETAILED DESCRIPTION OF THE INVENTION
[0025] Embodiments of the present invention provide a system and method for a park lock mechanism for narrow transmissions having tight packaging and weight constraints. The following description is presented to enable one of ordinary skill in the art to make and use the invention and is provided in the context of a patent application and its requirements.
[0026] Various modifications to the preferred embodiment and the generic principles and features described herein will be readily apparent to those skilled in the art. Thus, the present invention is not intended to be limited to the embodiment shown but is to be accorded the widest scope consistent with the principles and features described herein.
[0027] FIG. 1 illustrates a side view of a narrow transmission 100 including a park lock device, the park lock device in a “not parked” mode or position, and FIG. 2 illustrates a side view of narrow transmission 100 including the park lock device in a “parked” mode or position. The park lock device is a mechanical interlock that selectively engages with and disengages from a park lock gear 105 . Park lock gear 105 includes a rotational axis A which rotates together with a motor axis M within a transmission case, motor axis M coupled in turn to a wheel axis of a vehicle. The transmission case includes a pair of complementary mating half cases, a back half case 110 shown in FIG. 1 .
[0028] The park lock device includes a cooperating set of components: a park pawl 115 , a park rod 120 , a park sleeve 125 , a pawl torsional spring 130 , and a pawl stopper 135 . These components move within a single plane defined by the transmission case and are supported by the transmission case as further described herein.
[0029] Park lock gear 105 includes an outside diameter perimeter having a number N of distributed uniform concave portions 140 . Concave portions 140 cooperate with a pawl portion 145 of park pawl 115 for producing the modes described herein, those modes including the parked mode and the not parked mode. Park pawl 115 rotates about a pawl shaft 150 when pawl portion 145 engages with, and disengages from, concave portions 140 .
[0030] The engaging/disengaging rotation of park pawl 115 is initiated by a movement of park rod 120 . As further detailed below, park rod 120 and park pawl 115 make contact inside of park sleeve 125 , with the consequence that the park lock device enters into one of its modes (as further determined by the operational state of the other components of narrow transmission 100 ).
[0031] The movement of park rod 120 is responsive to a controller (not shown) that commands one of the parked mode and the not parked mode for narrow transmission 100 . While there are many types of controllers, in the present example, a software-controlled electromagnetic rotary actuator controls a rotation of a control shaft 155 . Control shaft 155 rotates between a not parked position (in FIG. 1 ) and a parked position ( FIG. 2 ). Control shaft 155 rotates when making these transitions between parked and not parked positions, however due to the nature of such electromechanical actuators, control shaft 155 sometimes does not exactly rotate.
[0032] Narrow transmission 100 compensates for any inexact rotation by mechanically limiting/finishing rotation of control shaft 155 by use of a detent plate 160 . Detent plate 160 includes a cam profile with two detents, one detent corresponding to the park position and one detent corresponding to the not parked position. The cam profile includes a number of curves and slopes joining the two detents. A detent spring 165 includes a cam profile follower 170 that limits any over rotation of control shaft 155 in both rotational directions due to physical stops at outside edges of the detents. Cam profile follower 170 inhibits any under rotation of control shaft 155 in both directions by either finishing a rotational transition or returning control shaft to its pre-transition position. The specifics are determined by the amount of actual rotation of control shaft 155 and where cam profile follower 170 is placed along the cam profile.
[0033] Detent spring 165 exerts sufficient torque on control shaft 155 through interaction with detent plate 160 to follow the cam profile and rotate control shaft 155 until cam profile follower 170 engages one of the two detents. A required torque to actuate parked mode from not parked mode is kept below a minimum torque provided by detent plate 160 and interacting detent spring 165 . In the embodiment of FIG. 1 , the cam profile is not symmetric having a different set of conditions to transition from parked to not parked as compared to a set conditions to transition from not parked to parked. The curves and slopes of the cam profile are configured to provide the desired response to rotational uncertainty in control shaft 155 and a required amount of torque for detent spring 165 for those desired responses.
[0034] Due to tight packaging requirements in the transmission case, detent spring 165 is a leaf spring mounted laterally from back half case 110 using a support 175 rather than having detent spring 165 mounted directly to the transmission case on the top or bottom surface of the spring in a conventional fashion. The particular configuration of detent spring 165 provides the necessary torques for cam profile follower 170 to affect movement of detent plate 160 while being sufficiently rigidly supported.
[0035] A proximal end 180 of park rod 120 includes a ninety degree bend provided with swaged elements to engage rotationally a mating aperture on detent plate 160 . Engagement/disengagement of the swaged end with detent plate 160 requires a rotation of control shaft 155 beyond the detent positions and therefore the swaged elements prevent accidental disengagement during operation.
[0036] The coupling of proximal end 180 to detent plate 160 converts rotation of control shaft 155 to lateral translation of park rod 120 . A distal end of park rod 120 (not shown in FIG. 1 because park rod 120 terminates within park sleeve 125 ) converts translation of park rod 120 into mechanical control of park pawl 115 as further described below. Pawl torsional spring 130 , coupled to pawl shaft 150 , rotationally biases park pawl 115 upwards and away from engagement with park lock gear 105 . The translation of park rod 120 overcomes this bias in appropriate situations to rotate park pawl 115 downwards toward engagement with park lock gear 105 .
[0037] Park sleeve 125 includes a cylindrical perimeter and rotates about a transverse axis 185 relative to back half case 110 . This rotation of park sleeve 125 allows self-alignment in response to internal interactions of park rod 120 and park pawl 115 . A magnitude of rotation of park sleeve 125 is limited by a bracket 190 coupled to a complementary external cutout in park sleeve 125 .
[0038] Pawl stopper 135 also includes a generally cylindrical perimeter and rotates about a transverse axis relative to back half case 110 . This rotation of pawl stopper 135 allows self-alignment in response to impacts of park pawl 115 . A magnitude of rotation of pawl stopper 135 is limited by bracket 190 coupled to a complementary external cutout in pawl stopper 135 . Bracket 190 thus concurrently retains both park sleeve 125 and pawl stopper 135 while permitting both structures to independently self-align to help meet space and weight budgets.
[0039] A feature of the disclosed embodiment is that transverse axis 185 , the transverse axis of pawl stopper 135 , a rotational axis of pawl shaft 150 , and a rotational axis of control shaft 155 are all parallel. A manufacturing and assembly advantage of the disclosed embodiment of the present invention is that these elements engage and rotate within parallel bores disposed in back half case 110 . A milling machine would be able to create all these bores in a single pass without removing/repositioning back half case 110 in between creation of some of the bores. This means that all of the bores are all accurately positioned relative to each other. This improves assembly accuracy as the functional positions of these components are fixed without use of other parts. In contrast, if this assembly required machining in multiple planes, the resulting accuracy of those assembly would be less than an assembly able to be machined in a single plane.
[0040] One critical component is positioning and operation of park sleeve 125 . Because park sleeve has a cylindrical perimeter it is easily installed into back half case 110 by inserting it into one of these accurately positioned bores. No other parts or brackets are needed to determine the operational position of park sleeve. The assembly is simplified in this fashion because no high accuracy position fixing bracket is required (such brackets can be complicated and possibly more expensive). A loose tolerance anti-rotation alignment bracket that limits rotation of park sleeve 125 replaces any position fixing bracket.
[0041] FIG. 3 illustrates a sectional view of a portion of the park lock device of FIG. 1 depicting an interaction of park rod 120 and park pawl 115 inside park sleeve 125 (not parked mode), FIG. 4 illustrates a sectional view of a portion of the park lock device of FIG. 2 depicting an interaction of park rod 120 and park pawl 115 inside park sleeve 125 (parked mode), and FIG. 5 illustrates a sectional view of a portion of the park lock device detailing component orientation during transitions between the not parked mode of FIG. 1 and the parked mode of FIG. 2 .
[0042] Park rod 120 includes a distal end 305 (e.g., a tip of park rod 120 ) opposite from proximal end 180 with a cam portion 310 disposed at distal end 305 and secured with an end stop. Cam portion 310 slidingly engages distal end 305 to move along park rod 120 between an extended position and a compressed position. A cam spring 315 disposed on distal end 305 between cam portion 310 and a stop 320 biases cam portion 310 towards the extended position. In the section view of FIG. 3 , cam portion 310 includes two sloped portions: a steep forward portion 325 and a shallower rearward portion 330 (while appearing flat, in actuality these surfaces are radially symmetric).
[0043] Park pawl 115 includes pawl portion 145 at a distal end away from pawl shaft 150 . Pawl portion 145 locks park lock gear 105 by engaging one uniform concave portion 140 . Park pawl 115 further includes a body portion 335 joining pawl shaft 150 to the distal end and a cam contact portion 340 also at the distal end opposing pawl portion 145 . Body portion 335 is laterally flat with pawl stopper 135 including a complementary flat chord 345 disposed on an intermediate portion of its cylindrical outer surface (that engages back half case 11 ), flat chord 345 rotating to align with body portion 335 when pawl stopper 135 is impacted by body portion 335 . Pawl stopper 135 , when self-aligning, rotates about its transverse axis so that flat chord 345 is substantially parallel to body portion 335 . Providing flat chord 345 over the entire width of body portion 335 distributes a contact load from each body portion 335 impact with pawl stopper 135 over a sufficiently large area that contact stresses are reduced to a desired level.
[0044] In FIG. 4 , park sleeve 125 includes an internal cam follower portion 405 that contacts cam portion 310 at a first contact point 410 along the slopes of cam portion 310 . First contact point 410 moves along cam portion 310 as cam portion 310 moves in and out of park sleeve 125 . (Note that there are some instances when park sleeve 125 does not contact cam portion 310 during operation of the park lock device.) Cam contact portion 340 contacts cam portion 310 at a second contact point 415 along the slopes of cam portion 310 . Second contact point 415 moves along cam portion 310 as cam portion 310 moves in and out of park sleeve 125 and park pawl 115 rotates.
[0045] In the parked mode shown in FIG. 4 , park sleeve 125 has self-aligned to produce a substantially zero resultant moment. The zero resultant moment is a consequence of the following particular arrangements. Park rod 120 is cylindrical at proximal end 180 and distal end 305 , distal end 305 including a longitudinal axis 420 . A line of action passes approximately through the transverse axis which is approximately passed through the center of park sleeve 125 . Longitudinal axis 420 is perpendicular to both a first imaginary line extending between transverse axis 185 and first contact point 410 as well as a second imaginary line extending between transverse axis 185 and second contact point 415 . This configuration provides that the resulting moment on park sleeve 125 is zero regardless of an angle that rearward portion 330 makes at first contact point 410 , a distance from transverse axis 185 to first contact point 410 or a magnitude of a force F at first contact point 410 . Further, park sleeve 125 self-aligns so that the distance from transverse axis 185 to first contact point 410 matches a distance from transverse axis 185 to second contact point 415 . Due to the resulting symmetric loading with respect to longitudinal axis 420 the resultant moment is also zero. Configuring park sleeve 125 and park rod 120 for relative self-alignment in park mode in this way provides two mechanisms to produce a zero resultant moment that reduces unnecessary stress on the park lock device.
[0046] Both park sleeve 125 and pawl stopper 135 rotate for self-alignment, with bracket 190 used for both retaining them within back half case 110 at about the proper alignment and limiting the magnitudes of their rotations during self-alignments. Bracket 190 attaches to back half case 110 to “trap” park sleeve 125 and pawl stopper 135 while the external cuts on outside edges of park sleeve 125 and pawl stopper 135 engage bracket 190 to provide the rotation limitation. The park sleeve 125 rotation range allows for cam portion 310 to freely enter and exit during transitions of the park lock device between modes. Pawl stopper 135 rotation range allows for impacts by body portion 335 to rotate pawl stopper 135 so flat chord 345 is substantially parallel to body portion 335 .
[0047] Two primary modes have been described above: parked mode and not parked mode. In normal operation, the park lock device transitions from the not parked mode shown in FIG. 1 to the parked mode shown in FIG. 2 and transitions from the parked mode to the not parked mode as determined by the controller. When transitioning from the parked mode to the not parked mode, the controller causes control shaft 155 to rotate clockwise (in FIG. 1 ) which translates park rod 120 to the right and causes cam portion 310 to more fully enter into park sleeve 125 . In transition as park rod 120 continues to translate to the right, as shown in FIG. 5 , forward portion 325 of cam portion 310 engages both cam follower portion 405 of park sleeve 125 and cam contact portion 340 of park pawl 115 . Further translation of park rod 120 to the right rotates park pawl 115 counterclockwise (downward in FIG. 5 ) since forward portion 325 engages both park sleeve 125 and park pawl 115 . At the completion of the translation of park rod 120 to the right, park pawl 115 , park sleeve 125 , and cam portion 310 have the relationship shown in FIG. 4 in which rearward portion 330 of cam portion 310 engages both park sleeve 125 and park pawl 115 in the parked mode. As long as the park lock device is configured as shown in FIG. 4 , park pawl 115 cannot disengage from park lock gear 105 and forces exerted on cam portion 310 by park pawl 115 are not capable of translating park rod 120 to the left to enable disengagement. Only by translation of park rod 120 to the left, such as by rotation of control shaft 155 counterclockwise, will cam portion 310 transition to the intermediate mode shown in FIG. 5 to enable park pawl 115 to rotate clockwise (upwards in FIG. 4 ) and disengage from park lock gear 105 .
[0048] When the EV is travelling faster than the park lock engagement speed and control shaft 155 moves to the park position, the park lock device is required to avoid entering into the park mode. FIG. 6 illustrates a sectional view of a portion of the park lock device detailing an operational mode with the controller in the parked position prior to the parking pawl engaging the park gear. When the EV speed slows to the lock speed or slower, the park lock device automatically enters into the park mode in normal fashion as described herein.
[0049] FIG. 7 illustrates a side view of park rod 120 , FIG. 8 illustrates a top view of park rod 120 , and FIG. 9 illustrates a sectional view of a mid-portion of park rod 120 about A-A identified in FIG. 7 . During a skid torque mode, park pawl 115 can impart significant bending/buckling loads to park rod 120 . Park rod 120 includes a mid-portion that has a cross-section which is generally oblong-shaped. The oblong having a major axis that is vertical. This oblong-shaped cross-section helps enable park rod 120 to better endure such skid torque mode.
[0050] FIG. 10 illustrates a top view of the park lock device components from FIG. 2 (park mode) isolated from the transmission case; and FIG. 11 illustrates a side view of the park lock device components of FIG. 10 . A pair of bolts 1005 is shown securing bracket 190 in place. Also illustrated is an enlarged head 1010 for pawl shaft 150 . Enlarged head 1010 interacts with a second half of the transmission case (not shown) that holds pawl shaft 150 in place while permitting it to freely turn. In this way no additional retention or mounting hardware is required, saving weight and decreasing component count.
[0051] FIG. 12 illustrates an end view of park sleeve 125 detailing an opening 1205 receiving cam portion 310 of parking rod 120 ; and FIG. 13 illustrates an isometric view of park sleeve 125 including receipt of cam portion 310 within opening 1205 . Parking rod 120 reciprocates in and out of opening 1205 with cam portion 310 engaging cam follower portion 405 . To help locate and guide parking rod 120 in this operation, opening 1205 is provided with an upper stopper 1210 and a pair of side-to-side guides 1215 . Upper stopper 1210 and side-to-side guides 1215 engage distal end 305 shown in FIG. 3 as it reciprocates to maintain operational alignment within the plane of the transmission. Opening 1205 does not include a lower stopper and is open opposite of cam follower portion 405 because cam contact portion 340 of park pawl 115 is located at this position. In this way park sleeve 125 sandwiches park pawl 115 (i.e., cam contact portion 340 ) and surrounds cam portion 310 with the aid of park pawl 115 . Distal end 305 is guided and aligned without use of additional parts as is sometimes required in conventional systems. Also shown in FIG. 13 is a cutout 1305 on an exterior portion of park sleeve 125 . Cutout 1305 cooperates with bracket 190 to provide rough rotational alignment of park sleeve 125 to properly orient opening 1205 and enable subsequent self-alignment.
[0052] The system and methods above has been described in general terms as an aid to understanding details of preferred embodiments of the present invention. In the description herein, numerous specific details are provided, such as examples of components and/or methods, to provide a thorough understanding of embodiments of the present invention. While the park lock device has been described in the context of a narrow transmission of the type commonly found in electric vehicles, the disclosed solution is applicable to other transmission systems and methods. Some features and benefits of the present invention are realized in such modes and are not required in every case. One skilled in the relevant art will recognize, however, that an embodiment of the invention can be practiced without one or more of the specific details, or with other apparatus, systems, assemblies, methods, components, materials, parts, and/or the like. In other instances, well-known structures, materials, or operations are not specifically shown or described in detail to avoid obscuring aspects of embodiments of the present invention.
[0053] Reference throughout this specification to “one embodiment”, “an embodiment”, or “a specific embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment of the present invention and not necessarily in all embodiments. Thus, respective appearances of the phrases “in one embodiment”, “in an embodiment”, or “in a specific embodiment” in various places throughout this specification are not necessarily referring to the same embodiment. Furthermore, the particular features, structures, or characteristics of any specific embodiment of the present invention may be combined in any suitable manner with one or more other embodiments. It is to be understood that other variations and modifications of the embodiments of the present invention described and illustrated herein are possible in light of the teachings herein and are to be considered as part of the spirit and scope of the present invention.
[0054] It will also be appreciated that one or more of the elements depicted in the drawings/figures can also be implemented in a more separated or integrated manner, or even removed or rendered as inoperable in certain cases, as is useful in accordance with a particular application.
[0055] Additionally, any signal arrows in the drawings/Figures should be considered only as exemplary, and not limiting, unless otherwise specifically noted. Furthermore, the term “or” as used herein is generally intended to mean “and/or” unless otherwise indicated. Combinations of components or steps will also be considered as being noted, where terminology is foreseen as rendering the ability to separate or combine is unclear.
[0056] As used in the description herein and throughout the claims that follow, “a”, “an”, and “the” includes plural references unless the context clearly dictates otherwise. Also, as used in the description herein and throughout the claims that follow, the meaning of “in” includes “in” and “on” unless the context clearly dictates otherwise.
[0057] The foregoing description of illustrated embodiments of the present invention, including what is described in the Abstract, is not intended to be exhaustive or to limit the invention to the precise forms disclosed herein. While specific embodiments of, and examples for, the invention are described herein for illustrative purposes only, various equivalent modifications are possible within the spirit and scope of the present invention, as those skilled in the relevant art will recognize and appreciate. As indicated, these modifications may be made to the present invention in light of the foregoing description of illustrated embodiments of the present invention and are to be included within the spirit and scope of the present invention.
[0058] Thus, while the present invention has been described herein with reference to particular embodiments thereof, a latitude of modification, various changes and substitutions are intended in the foregoing disclosures, and it will be appreciated that in some instances some features of embodiments of the invention will be employed without a corresponding use of other features without departing from the scope and spirit of the invention as set forth. Therefore, many modifications may be made to adapt a particular situation or material to the essential scope and spirit of the present invention. It is intended that the invention not be limited to the particular terms used in following claims and/or to the particular embodiment disclosed as the best mode contemplated for carrying out this invention, but that the invention will include any and all embodiments and equivalents falling within the scope of the appended claims. Thus, the scope of the invention is to be determined solely by the appended claims. | A park lock of a transmission, including a park gear; a park pawl rotating about a pawl shaft, the park pawl having a pawl portion locking the park gear, the park pawl including a cam contact portion; a park rod responsive to an operation of a controller, the park rod having a cam portion pressing the cam contact portion to have park pawl engage the park gear; a park sleeve receiving the cam portion and defining a first contact point providing a reactive force to the cam contact portion of the park pawl pressing against the cam portion at a second contact point; a pawl torsional spring biasing the park pawl towards disengagement; and a pawl stopper limiting the rotation of the park pawl wherein motions are constrained within a plane of the transmission and components are rotatingly disposed in parallel axis bores in one half of a transmission case. | 8 |
PRIORITY TO RELATED APPLICATIONS
This application claims the benefit of European Patent Application No. 08166184.5, field Oct. 9, 2008, which is hereby incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
The three main mammalian tachykinins, substance P(SP), neurokinin A (NKA) and neurokinin B (NKB) belong to the family of neuropeptides sharing the common COOH-terminal pentapeptide sequence of Phe-X-Gly-Leu-Met-NH 2 . As neurotransmitters, these peptides exert their biological activity via three distinct neurokinin (NK) receptors termed as NK-1, NK-2 and NK-3. SP binds preferentially to the NK-1 receptor, NKA to the NK-2 and NKB to the NK-3 receptor.
The NK-3 receptor is characterized by a predominant expression in CNS and its involvement in the modulation of the central monoaminergic system has been shown. These properties make the NK-3 receptor a potential target for central nervous system disorders such as anxiety, depression, bipolar disorders, Parkinson's disease, schizophrenia and pain ( Neurosci. Letters, 2000, 283, 185-188 ; Exp. Opin. Ther. Patents 2000, 10, 939-960 ; Neuroscience, 1996, 74, 403-414 ; Neuropeptides, 1998, 32, 481-488).
Schizophrenia is one of the major neuropsychiatric disorders, characterized by severe and chronic mental impairment. This devastating disease affects about 1% of the world's population. Symptoms begin in early adulthood and are followed by a period of interpersonal and social dysfunction. Schizophrenia manifests as auditory and visual hallucinations, paranoia, delusions (positive symptoms), blunted affect, depression, anhedonia, poverty of speech, memory and attention deficits as well as social withdrawal (negative symptoms).
For decades scientists and clinicians have made efforts with the aim of discovering an ideal agent for the pharmacological treatment of schizophrenia. However, the complexity of the disorders, due to a wide array of symptoms, has hampered those efforts. There are no specific focal characteristics for the diagnosis of schizophrenia and no single symptom is consistently present in all patients. Consequently, the diagnosis of schizophrenia as a single disorder or as a variety of different disorders has been discussed but not yet resolved. The major difficulty in the development of a new drug for schizophrenia is the lack of knowledge about the cause and nature of this disease. Some neurochemical hypotheses have been proposed on the basis of pharmacological studies to rationalize the development of a corresponding therapy: the dopamine, the serotonin and the glutamate hypotheses. But taking into account the complexity of schizophrenia, an appropriate multireceptor affinity profile might be required for efficacy against positive and negative signs and symptoms. Furthermore, an ideal drug against schizophrenia would preferably have a low dosage allowing once-per-day dosage, due to the low adherence of schizophrenic patients.
In recent years clinical studies with selective NK1 and NK2 receptor antagonists appeared in the literature showing results for the treatment of emesis, depression, anxiety, pain and migraine (NK1) and asthma (NK2 and NK1). The most exciting data were produced in the treatment of chemotherapy-induced emesis, nausea and depression with NK1 and in asthma with NK2-receptor antagonists. In contrast, no clinical data on NK3 receptor antagonists have appeared in the literature until 2000. Osanetant (SR 142,801) from Sanofi-Synthelabo was the first identified potent and selective non-peptide antagonist described for the NK3 tachykinin receptor for the potential treatment of schizophrenia, which was reported in the literature ( Current Opinion in Investigational Drugs, 2001,2(7), 950-956 and Psychiatric Disorders Study 4 , Schizophrenia , June 2003, Decision Recources, Inc., Waltham, Mass.). The proposed drug SR 142,801 has been shown in a phase II trial as active on positive symptoms of schizophrenia, such as altered behavior, delusion, hallucinations, extreme emotions, excited motor activity and incoherent speech, but inactive in the treatment of negative symptoms, which are depression, anhedonia, social isolation or memory and attention deficits.
The neurokinin-3 receptor antagonists have been described as useful in pain or inflammation, as well as in schizophrenia, Exp. Opinion. Ther. Patents (2000), 10(6), 939-960 and Current Opinion in Investigational Drugs, 2001, 2(7), 950-956 956 and Psychiatric Disorders Study 4 , Schizophrenia , June 2003, Decision Recources, Inc., Waltham, Mass.). Objects of the present invention are novel compounds of formula I, their manufacture, medicaments based on a compound in accordance with the invention and their production as well as the use of compounds of formula I in the control or prevention of illnesses such as depression, pain, bipolar disorders, psychosis, Parkinson's disease, schizophrenia, anxiety and attention deficit hyperactivity disorder (ADHD).
SUMMARY OF THE INVENTION
The present invention provides a compound of formula I
wherein
Ar 1 is aryl or heteroaryl; Ar 2 is aryl or heteroaryl; R 1 is hydrogen, halogen, hydroxy, lower alkyl, lower alkoxy, lower alkyl substituted by halogen, lower alkoxy substituted by halogen, S-lower alkyl, —S(O) 2 -lower alkyl, —S(O) 2 -di-lower alkyl amino, cyano, amino, mono or di-lower alkyl amino, C(O)-lower alkyl, NHC(O)-lower alkyl, cycloalkyl, heterocyclyl, or heteroaryl optionally substituted by lower alkyl; R 2 is hydrogen, halogen, lower alkyl, lower alkoxy, lower alkyl substituted by halogen or cyano; R 3 is hydrogen, halogen, lower alkyl or lower alkyl substituted by halogen; n is 1, 2 or 3; wherein when n is 2 or 3, each R 1 is the same or different; o is 1, 2 or 3; wherein when o is 2 or 3, each R 2 is the same or different; and p is 1, 2 or 3; wherein when p is 2 or 3, each R 4 is the same or different; or a pharmaceutically active salt thereof.
The invention includes all stereoisomeric forms, including individual diastereoisomers and enantiomers of the compound of formula (I) as well as racemic and non-racemic mixtures thereof.
Compounds of the invention are high potential NK-3 receptor antagonists for the treatment of depression, pain, psychosis, Parkinson's disease, schizophrenia, anxiety and attention deficit hyperactivity disorder (ADHD).
The preferred indications using the compounds of the present invention are depression, psychosis, Parkinson's disease, schizophrenia, anxiety and attention deficit hyperactivity disorder (ADHD).
DETAILED DESCRIPTION OF THE INVENTION
The following definitions of the general terms used in the present description apply irrespective of whether the terms in question appear alone or in combination. It must be noted that, as used in the specification and the appended claims, the singular forms “a”, “an,” and “the” include plural forms unless the context clearly dictates otherwise.
As used herein, the term “lower alkyl” denotes a straight- or branched-chain hydrocarbon group containing from 1-8 carbon atoms, for example, methyl, ethyl, propyl, isopropyl, n-butyl, i-butyl, t-butyl and the like. Preferred lower alkyl groups are groups with 1-4 carbon atoms.
The term “lower alkyl substituted by halogen” denotes a lower alkyl group as defined above, wherein at least one hydrogen atom is replaced by halogen, for example —CF 3 , —CHF 2 , —CH 2 F, —CH 2 CF 3 , —CH 2 CH 2 CF 3 , —CH 2 CF 2 CF 3 and the like. Preferred lower alkyl substituted by halogen groups are groups having 1-4 carbon atoms.
The term “halogen” denotes chlorine, iodine, fluorine and bromine.
The term “lower alkoxy” denotes an O—R group wherein R is lower alkyl as defined above.
The term “lower alkoxy substituted by halogen” denotes a lower alkoxy group as defined above, wherein at least one hydrogen atom is replaced by halogen, for example, —OCF 3 , —OCHF 2 , —OCH 2 F, —OCH 2 CF 3 , —OCH 2 CH 2 CF 3 , —OCH 2 CF 2 CF 3 and the like.
The term “cycloalkyl” denotes a saturated carbon ring containing from 3-7 carbon atoms, for example, cyclopropyl, cyclobutyl, cyclpentyl, cyclohexyl, cycloheptyl, and the like.
The term “aryl” denotes a cyclic aromatic hydrocarbon radical consisting of one or more fused rings containing 6-14 carbon atoms in which at least one ring is aromatic in nature, for example phenyl, benzyl, naphthyl or indanyl. Preferred is phenyl.
The term “heteroaryl” denotes a cyclic aromatic radical consisting of one or more fused rings containing 5-14 ring atoms, preferably containing 5-10 ring atoms, in which at least one ring is aromatic in nature, and which contains at least one heteroatom selected from N, O and S, for example quinoxalinyl, dihydroisoquinolinyl, pyrazin-2-yl, pyrazol-1-yl, 2,4-dihydro-pyrazol-3-one, pyridinyl, isoxazolyl, benzo[1,3]dioxol, pyridyl, pyrimidin-4-yl, pyrimidin-5-yl, benzotriazol-5-yl, benzoimidazol-5-yl, [1,3,4]-oxadiazol-2-yl, [1,2,4]triazol-1-yl, [1,6]naphthyridin-2-yl, imidazo[4,5-b]pyridine-6-yl, tetrazolyl, thiazolyl, thiadiazolyl, thienyl, furyl, imidazol-1-yl, or benzofuranyl. Preferred heteroaryl group is pyridine-2, 3 or 4-yl.
The term heterocyclyl denotes a five or six membered nonaromatic ring, containing one or two heteroatoms selected from N, S and O, for example the following groups: morpholinyl, 1,1-dioxo-1-6-isothiazolidin-2-yl, piperazinyl, optionally substituted in 1 position by carboxylic acid tert-butyl ester or is 1,1,-dioxo-1-6-thiomorpholin-4-yl.
“Pharmaceutically acceptable,” such as pharmaceutically acceptable carrier, excipient, etc., means pharmacologically acceptable and substantially non-toxic to the subject to which the particular compound is administered.
The term “pharmaceutically acceptable acid addition salts” embraces salts with inorganic and organic acids, such as hydrochloric acid, nitric acid, sulfuric acid, phosphoric acid, citric acid, formic acid, fumaric acid, maleic acid, acetic acid, succinic acid, tartaric acid, methanesulfonic acid, p-toluenesulfonic acid and the like.
“Therapeutically effective amount” means an amount that is effective to prevent, alleviate or ameliorate symptoms of disease or prolong the survival of the subject being treated.
Compounds of formula I, wherein Ar 1 is aryl and Ar 2 is phenyl are preferred.
Preferred specific compounds are the following:
4-{(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidine-1-carbonyl}-benzonitrile; 3-{(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidine-1-carbonyl}-benzonitrile; 4-({[(3RS,4SR)-1-(4-cyano-benzoyl)-4-(3,4-dichloro-phenyl)-pyrrolidin-3-yl]-methyl-amino}-methyl)-2-fluoro-benzonitrile; 4-{(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidine-1-carbonyl}-3-fluoro-benzonitrile; {(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(2-fluoro-5-methanesulfonyl-phenyl)-methanone; {(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(4-methanesulfonyl-phenyl)-methanone; 4-{(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidine-1-carbonyl}-2-methyl-benzonitrile; 1-(4-{(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidine-1-carbonyl}-phenyl)-ethanone; {(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(4-morpholin-4-yl-phenyl)-methanone; {(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(4-[1,2,4]triazol-1-yl-phenyl)-methanone; {(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(4-imidazol-1-yl-phenyl)-methanone; {(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-[4-(1,1-dioxo-1-6-isothiazolidin-2-yl)-phenyl]-methanone; {(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(4-pyridin-2-yl-phenyl)-methanone; {(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(4-pyridin-3-yl-phenyl)-methanone; {(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(4-pyridin-4-yl-phenyl)-methanone; {(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(4-[1,3,4]oxadiazol-2-yl-phenyl)-methanone; N-(4-{(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidine-1-carbonyl}-phenyl)-acetamide; 4-{(3SR,4RS)-3-(4-chloro-3-fluoro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidine-1-carbonyl}-benzonitrile; {(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(4-oxazol-5-yl-phenyl)-methanone; and 4-{(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[methyl-(4-trifluoromethyl-benzyl)-amino]-pyrrolidine-1-carbonyl}-benzonitrile.
Compounds of formula I, wherein Ar 1 is heteroaryl and Ar 2 is phenyl are further preferred.
Preferred specific compounds are the following:
benzo[1,3]dioxol-5-yl-{(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-methanone; {(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(6-methyl-pyridin-3-yl)-methanone; 5-{(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidine-1-carbonyl}-pyridine-2-carbonitrile; {(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(6-morpholin-4-yl-pyridin-3-yl)-methanone; {(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(6-fluoro-pyridin-3-yl)-methanone; {(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(6-methoxy-pyridin-3-yl)-methanone; {(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(6-pyrazol-1-yl-pyridin-3-yl)-methanone; {(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(2-methyl-pyridin-4-yl)-methanone; {(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(6-hydroxy-pyridin-3-yl)-methanone; {(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-[1,6]naphthyridin-2-yl-methanone; {(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(2-methoxy-pyrimidin-5-yl)-methanone; (3H-benzotriazol-5-yl)-{(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-methanone; (3H-benzoimidazol-5-yl)-{(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-methanone; 4-(5-{(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidine-1-carbonyl}-pyridin-2-yl)-piperazine-1-carboxylic acid tert-butyl ester; and {(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-[6-(1,1-dioxo-1-6-thiomorpholin-4-yl)-pyridin-3-yl]-methanone.
Preparation of compounds of formula I of the present invention can be carried out in sequential or convergent synthetic routes. Syntheses of the compounds of the invention are shown in the following schemes. The skills required for carrying out the reaction and purification of the resulting products are known to those skilled in the art. The substituents and indices used in the following description of the processes have the significance given herein before unless indicated to the contrary.
The compounds of formula I can be manufactured by the methods given below, by the methods given in the examples or by analogous methods. Appropriate reaction conditions for the individual reaction steps are known to a person skilled in the art. The reaction sequence is not limited to the one displayed in the schemes, however, depending on the starting materials and their respective reactivity the sequence of reaction steps can be freely altered. Starting materials are either commercially available or can be prepared by methods analogous to the methods given below, by methods described in references cited in the description or in the examples, or by methods known in the art.
The present compounds of formula I and their pharmaceutically acceptable salts can be prepared by methods, known in the art, for example by the process variants described below, which process comprises
a) coupling a compound of formula
with a suitable acid chloride or carboxylic acid of formula
R—C(O)—Ar 1 —(R 1 ) n
wherein R is Cl or hydroxy,
to obtain a compound of formula
wherein the substituents R 1 , R 2 , R 3 , Ar 1 , Ar 2 and the definitions o, n and p are described above, or
b) alkylating a compound of formula
with a compound of formula
Hal-CH 2 —Ar 2 —(R 2 ) o
to obtain a compound of formula
wherein the substituents R 1 , R 2 , R 3 , Ar 1 , Ar 2 and the definitions o, n and p are described above, and, if desired, converting the compounds obtained into pharmaceutically acceptable acid addition salts.
The preparation of compounds of formula I is further described in more detail in schemes I-II and in examples 1-70.
The pyrrolidines IV were prepared via a stereo specific 1,3-dipolar cycloaddition between 2-nitrostyrene derivatives II and the azomethine ylide generated in situ from the N-(methoxymethyl)-N-(phenylmethyl)-N-(trimethylsilyl)methylamine III in the presence of a catalytic amount of acid, such as TFA. Reduction of the nitro moiety using standard conditions for example SnCl 2 .H 2 O yielded V. The amino moiety was subsequently methylated in a two step sequence, involving first the preparation of the ethyl carbamate followed by its reduction with borane to produce VI. Reductive amination reaction between VI and an aldehyde yielded VII. Alternatively, VII could be prepared by alkylation. Selective N-debenzylation was then carried out using several known procedures which are compatible with the substitution patterns of the aromatic rings to afford VIII. Finally derivatives I were prepared via a coupling with an acid chloride or carboxylic acid.
Alternatively, the pyrrolidine derivatives I, were also prepared via the route highlighted scheme 2. The secondary amine of the intermediate VI can be BOC-protected to afford IX. Selective N-debenzylation was then carried out using several known procedures which are compatible with the substitution patterns of the aromatic rings to afford X. Standard coupling reaction with an acid chloride or carboxylic acid gave XI, which could then undergo a deprotection with for instance TFA to give XII. The secondary amine was then alkylated via a standard reductive amination or via an alkylation with an alkyl-halide to afford the derivatives I.
Experimental Part
Abbreviations
CH 2 Cl 2 =dichloromethane;
DMAP=dimethylaminopyridine;
HOBt=1-hydroxy-benzotriazol hydrat;
EDC=1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride;
Et 3 N=triethylamine;
EtOAc=ethyl acetate;
H=hexane;
RT=room temperature;
General Procedure I (Amide Coupling)
To a stirred solution of a carboxylic acid derivative (commercially available or known in the literature) (1 mmol) in 10 mL of CH 2 Cl 2 was added (1.3 mmol) of EDC, (1.3 mmol) of HOBt and Et 3 N (1.3 mmol). After one hour at RT, was added a pyrrolidine intermediate of general formula (VIII or X). The mixture was stirred at RT over night and then poured onto water and extracted with CH 2 Cl 2 . The combined organic phases were dried over Na 2 SO 4 and concentrated under vacuo. Flash chromatography or preparative HPLC afforded the title compound.
General Procedure II
To a stirred solution of a pyrrolidine intermediate VIII (1 mmol) in CH 2 Cl 2 (15 ml) at RT were added ethyl-diisopropyl-amine (2 mmol) and an acid chloride of formula ArCOCl (1.1 mmol). Stirring was continued until completion of the reaction. The reaction mixture was then concentrated under vacuo and purification by flash chromatography on SiO 2 or preparative HPLC.
General Procedure III (Reductive Amination)
To a stirred solution of a pyrrolidine intermediate XII (1.00 mmol) in MeOH (6 ml) was added the aldehyde (1.20 mmol). Then a solution of NaBH 3 CN (1.3 mol) in MeOH (1.5 ml) and AcOH (0.01 ml) were added. The reaction mixture was stirred overnight at RT, concentrated under vacuo, diluted with EtOAc, washed with H 2 O. The organic phases were dried over Na 2 SO 4 and the product purified by flash chromatography (SiO 2 ) or preparative HPLC to afford the desired compound.
As mentioned earlier, the compounds of formula I and their pharmaceutically usable addition salts possess valuable pharmacological properties. Compounds of the present invention are antagonists of neurokinin 3 (NK-3) receptors. The compounds were investigated in accordance with the tests given hereinafter.
Experimental Procedure
The compounds were investigated in accordance with the tests given hereinafter.
[ 3 H]SR142801 competition binding assay
hNK3 receptor binding experiment were performed using [ 3 H]SR142801 (Catalog No. TRK1035, specific activity: 74.0 Ci/mmol, Amersham, GE Healthcare UK limited, Buckinghamshire, UK) and membrane isolated from HEK293 cells transiently expressing recombinant human NK3 receptor. After thawing, the membrane homogenates were centrifuged at 48,000×g for 10 min at 4° C., the pellets were resuspended in the 50 mM Tris-HCl, 4 mM MnCl 2 , 1 μM phosphoramidon, 0.1% BSA binding buffer at pH 7.4 to a final assay concentration of 5 μg protein/well. For inhibition experiments, membranes were incubated with [ 3 H]SR142801 at a concentration equal to K D value of radioligand and 10 concentrations of the inhibitory compound (0.0003-10 μM) (in a total reaction volume of 500 μl) for 75 min at room temperature (RT). At the end of the incubation, membranes were filtered onto unitfilter (96-well white microplate with bonded GF/C filter preincubated 1 h in 0.3% PEI+0.3% BSA, Packard BioScience, Meriden, Conn.) with a Filtermate 196 harvester (Packard BioScience) and washed 4 times with ice-cold 50 mM Tris-HCl, pH 7.4 buffer. Nonspecific binding was measured in the presence of 10 μM SB222200 for both radioligands. The radioactivity on the filter was counted (5 min) on a Packard Top-count microplate scintillation counter with quenching correction after addition of 45 μl of microscint 40 (Canberra Packard S. A., Zürich, Switzerland) and shaking for 1 h. Inhibition curves were fitted according to the Hill equation: y=100/(1+(x/IC 50 ) nH ), where n H =slope factor using Excel-fit 4 software (Microsoft). IC 50 values were derived from the inhibition curve and the affinity constant (K i ) values were calculated using the Cheng-Prussoff equation K i =IC 50 /(1+[L]/K D ) where [L] is the concentration of radioligand and K D is its dissociation constant at the receptor, derived from the saturation isotherm. All experiments were performed in duplicate and the mean±standard error (SEM) of the individual K i values was calculated.
The K i values for some compounds with a hNK-3 receptor affinity<0.05 μM are shown in the following table 1.
TABLE 1
Example
Data K i [μM]
6
0.0209
9
0.0474
17
0.0383
18
0.042
19
0.0129
20
0.0417
22
0.0302
23
0.0066
24
0.0068
25
0.0152
26
0.0148
27
0.0057
28
0.0356
29
0.0084
30
0.0028
33
0.0111
38
0.009
40
0.0027
41
0.0107
42
0.0335
43
0.0051
44
0.0056
45
0.0025
47
0.0023
48
0.0478
51
0.0146
57
0.0223
59
0.0318
60
0.0173
61
0.0373
63
0.0247
64
0.002
66
0.0126
67
0.0045
68
0.0146
The present invention also provides pharmaceutical compositions containing compounds of the invention, for example compounds of formulae (I-a) to (I-e), or pharmaceutically acceptable salts thereof and a pharmaceutically acceptable carrier. Such pharmaceutical compositions can be in the form of tablets, coated tablets, dragées, hard and soft gelatine capsules, solutions, emulsions or suspensions. The pharmaceutical compositions also can be in the form of suppositories or injectable solutions.
The pharmaceutical compositions of the invention, in addition to one or more compounds of the invention, contain a pharmaceutically acceptable carrier. Suitable pharmaceutically acceptable carriers include pharmaceutically inert, inorganic or organic carriers. Lactose, corn starch or derivatives thereof, talc, stearic acid or its salts etc can be used as such excipients e.g. for tablets, dragées and hard gelatin capsules.
Suitable excipients for soft gelatin capsules are e.g. vegetable oils, waxes, fats, semi-solid and liquid polyols etc.
Suitable excipients for the manufacture of solutions and syrups are e.g. water, polyols, saccharose, invert sugar, glucose etc.
Suitable excipients for injection solutions are e.g. water, alcohols, polyols, glycerol, vegetable oils etc.
Suitable excipients for suppositories are e.g. natural or hardened oils, waxes, fats, semi-liquid or liquid polyols etc.
Moreover, the pharmaceutical compositions can contain preservatives, solubilizers, stabilizers, wetting agents, emulsifiers, sweeteners, colorants, flavorants, salts for varying the osmotic pressure, buffers, masking agents or antioxidants. They can also contain still other therapeutically valuable substances.
The dosage at which compounds of the invention can be administered can vary within wide limits and will, of course, be fitted to the individual requirements in each particular case. In general, in the case of oral administration a daily dosage of about 10 to 1000 mg per person of a compound of general formula I should be appropriate, although the above upper limit can also be exceeded when necessary.
EXAMPLE A
Tablets of the following composition are manufactured in the usual manner:
g/tablet
Active substance
5
Lactose
5
Corn starch
5
Microcrystalline cellulose
34
Magnesium stearate
1
Tablet weight
100
EXAMPLE B
Capsules of the following composition are manufactured:
mg/capsule
Active substance
10
Lactose
155
Corn starch
30
Talc
5
Capsule fill weight
200
The active substance, lactose and corn starch are firstly mixed in a mixer and then in a comminuting machine. The mixture is returned to the mixer, the talc is added thereto and mixed thoroughly. The mixture is filled by machine into hard gelantine capsules.
EXAMPLE C
Suppositories of the following composition are manufactured:
mg/supp.
Active substance
15
Suppository mass
1285
Total
1300
The suppository mass is melted in a glass or steel vessel, mixed thoroughly and cooled to 45° C. Thereupon, the finely powdered active substance is added thereto and stirred until it has dispersed completely. The mixture is poured into suppository moulds of suitable size, left to cool, the suppositories are then removed from the moulds and packed individually in wax paper or metal foil.
The following Examples illustrate the present invention without limiting it. All temperatures are given in degrees Celsius.
Process for preparation of pyrrolidine intermediates of formula VIII
Pyrrolidine VIII-1
[(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine
a) (3SR,4RS)-1-Benzyl-3-(3,4-dichloro-phenyl)-4-nitro-pyrrolidine
A solution of N-(methoxymethyl)-N-(phenylmethyl)-N-(trimethylsilyl)methylamine (1.96 g, 8.2 mmol) in CH 2 Cl 2 (10 ml) was added drop wise, over a 30 minutes period, to a stirred solution of 1,2-dichloro-4-((E)-2-nitro-vinyl)-benzene (1.0 g, 4.58 mmol) and trifluoroacetic acid (52 mg, 4.45 mmol) in CH 2 Cl 2 (5 ml) at 0° C. The ice bath was removed, and the solution was stirred at 25° C. for an additional 48 h. It was then concentrated and purification by flash chromatography (SiO 2 , EtOAc/H 1:4) afforded 1.00 g (62%) of the title compound as a colorless oil. ES-MS m/e: 351.4 (M+H + ).
b) (3RS,4SR)-1-Benzyl-4-(3,4-dichloro-phenyl)-pyrrolidin-3-ylamine
To a stirred solution of (3SR,4RS)-1-benzyl-3-(3,4-dichloro-phenyl)-4-nitro-pyrrolidine (15.0 g, 0.0427 mol) in EtOAc (200 ml) was added portionwise SnCl 2 .2H 2 O (43.36 g, 0.192 mol). The reaction mixture was then heated at reflux for 4 hours, cooled down to RT and a saturated aqueous solution of NaHCO 3 (500 ml) was added. The salts were filtered off and the product extracted with EtOAc. The organic phases were then dried over Na 2 SO 4 , and concentration under vacuum gave 9.30 g (75%) of the title compound as a light yellow oil. The product was then used in the next step without further purification. ES-MS m/e: 321.1 (M+H + ).
c) [(3RS,4SR)-1-Benzyl-4-(3,4-dichloro-phenyl)-pyrrolidin-3-yl]-methyl-amine
To a solution of (3RS,4SR)-1-benzyl-4-(3,4-dichloro-phenyl)-pyrrolidin-3-ylamine (9.2 g, 0.028 mol) in THF (100 ml) was added a solution of K 2 CO 3 (7.91 g, 0.057 mol) in H 2 O (35 ml). After 10 minutes, ethyl chloroformate (2.86 ml, 0.030 mol) was added and stirring was continued at RT for an additional 4 h. The intermediate carbamate was then extracted with Et 2 O, dried over Na 2 SO 4 and concentrated under vacuo to give viscous oil. The oil was taken up in THF (100 ml) and a solution of borane in THF (1M) was added (114.5 ml). The reaction mixture was then heated at 65° C. over night, cooled to RT and carefully quenched with conc. HCl (100 ml). The mixture was then heated at 80° C. for 2 h, cooled to RT, concentrated under vacuo, diluted with Et 2 O (100 ml) and neutralized with an aqueous solution of NaHCO 3 . The organic phases were dried over Na 2 SO 4 and the product purified by flash chromatography (SiO 2 , CH 2 Cl 2 /MeOH 9:1) to afford 7.31 g (76%) of the title compound as a colorless oil. ES-MS m/e: 335.3 (M+H + ).
d) [(3RS,4SR)-1-Benzyl-4-(3,4-dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine
To a stirred solution of [(3RS,4SR)-1-Benzyl-4-(3,4-dichloro-phenyl)-pyrrolidin-3-yl]-methyl-amine (3.5 g, 0.010 mol) in MeOH (60 ml) was added 3-fluoro-4-trifluoromethyl-benzaldehyde (2.10 g, 0.0109 mol). Then a solution of NaBH 3 CN (0.79 g, 0.012 mol) in MeOH (15 ml) and AcOH (0.1 ml) were added. The reaction mixture was stirred overnight at RT, concentrated under vacuo, diluted with EtOAc, washed with H 2 O. The organic phases were dried over Na 2 SO 4 and the product purified by flash chromatography (SiO 2 , EtOAc/Heptane 1:4) to afford 3.31 g (6 2%) of the title compound as a colorless oil.
e) [3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine
To a stirred solution of [(3RS,4SR)-1-benzyl-4-(3,4-dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4trifluoromethyl-benzyl)-methyl-amine (3.30 g, 6.45 mmol) in CH 3 CN (45 ml) at RT, was added 2,2,2-trichloroethyl chloroformate (1.30 ml, 9.67 mmol). The reaction mixture was stirred at RT for 3 hours, concentrated under vacuo. The residue was dissolved in AcOH (10 ml) and zinc dust (1.0 g) was added portion wise over 3 hours. The solvent was evaporated, the residue diluted in EtOAc and the organic phase was washed with an aqueous solution of NaHCO 3 . The organic phase was dried over Na 2 SO 4 , concentrated under vacuo to afford 1.43 g (53%) of the tile compound as a colorless oil. ES-MS m/e: 421.0 (M+H + ).
Pyrrolidine VIII-2
[(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-methyl-(4-trifluoromethyl-benzyl)-amine
a)[(3RS,4SR)-1-Benzyl-4-(3,4-dichloro-phenyl)-pyrrolidin-3-yl]-methyl-(4-trifluoromethyl-benzyl)-amine
To a stirred solution of [(3RS,4SR)-1-benzyl-4-(3,4-dichloro-phenyl)-pyrrolidin-3-yl]-methyl-amine (0.35 g, 1.04 mmol) in THF (6 ml) was added 1-bromomethyl-4-trifluoromethyl-benzene (0.27 g, 1.15 mmol) and Et 3 N (0.148 ml, 1.45 mmol). The reaction mixture was stirred overnight at RT and concentrated under vacuo. The product purified by flash chromatography (SiO 2 , EtOAc/Heptane 1:4) to afford 130 mg (29%) of the title compound as a colorless oil. ES-MS m/e: 492.9 (M+H + ).
b)[(3RS,4SR)-4-(3A-Dichloro-phenyl)-pyrrolidin-3-yl]-methyl-(4-trifluoromethyl-benzyl)-amine
To a stirred solution of [(3RS,4SR)-1-benzyl-4-(3,4-dichloro-phenyl)-pyrrolidin-3-yl]-methyl-(4-trifluoromethyl-benzyl)-amine (160 mg, 0.32 mmol) in CH 3 CN (5 ml) at RT, was added 2,2,2-trichloroethyl chloroformate (0.070 ml, 0.48 mmol). The reaction mixture was stirred at RT for 3 hours, concentrated under vacuo. The residue was dissolved in AcOH (3 ml) and zinc dust (80 mg) was added portion wise over 1 hours. The solvent was evaporated, the residue diluted in EtOAc and the organic phase was washed with an aqueous solution of NaHCO 3 . The organic phase was dried over Na 2 SO 4 and concentrated under vacuo. The product was purified by column chromatography (CH 2 Cl 2 /MeOH: 9/1) to afford 85 mg (65%) of the tile compound as a colorless oil. ES-MS m/e: 403.4 (M+H + ).
Pyrrolidine VIII-3
[(3RS,4SR)-4-(4-Chloro-3-fluoro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine
a) (3SR,4RS)-1-Benzyl-3-(4-chloro-3-fluoro-phenyl)-4-nitro-pyrrolidine
A solution of N-(methoxymethyl)-N-(phenylmethyl)-N-(trimethylsilyl)methylamine (1.00 g, 4.2 mmol) in CH 2 Cl 2 (5 ml) was added drop wise, over a 30 minutes period, to a stirred solution of 1-chloro-2-fluoro-4-((E)-2-nitro-vinyl)-benzene (0.68 g, 3.37 mmol) and trifluoroacetic acid (30 ul) in CH 2 Cl 2 (5 ml) at 0° C. The ice bath was removed, and the solution was stirred at 25° C. for an additional 48 h. It was then concentrated and purification by flash chromatography (SiO 2 , EtOAc/H 1:4) afforded 0.78 g (55%) of the title compound as a colorless oil. ES-MS m/e: 335.2 (M+H + ).
b) (3RS,4SR)-1-Benzyl-4-(4-chloro-3-fluoro-phenyl)-pyrrolidin-3-ylamine
To a stirred solution of (3SR,4RS)-1-benzyl-3-(4-chloro-3-fluoro-phenyl)-4-nitro-pyrrolidine (0.78 g, 2.33 mmol) in EtOAc (15 ml) was added portion wise SnCl 2 .2H 2 O (2.63 g, 11.6 mmol). The reaction mixture was then heated at reflux for 4 hours, cooled down to RT and a saturated aqueous solution of NaHCO 3 (500 ml) was added. The salts were filtered off and the product extracted with EtOAc. The organic phases were then dried over Na 2 SO 4 , and concentration under vacuum. A column chromatography (CH 2 Cl 2 /MeOH 95/5) gave 0.46 g (65%) of the title compound as a light brown oil. ES-MS m/e: 305.1 (M+H + ).
c) [(3RS,4SR)-1-Benzyl-4-(4-chloro-3-fluoro-phenyl)-pyrrolidin-3-yl]-methyl-amine
To a solution of (3RS,4SR)-1-benzyl-4-(4-chloro-3-fluoro-phenyl)-pyrrolidin-3-ylamine (0.46 g, 1.51 mmol) in THF (5 ml) was added a solution of K 2 CO 3 (0.419 g, 3.0 mmol) in H 2 O (2 ml). After 10 minutes, ethyl chloroformate (0.3 ml, 3.0 mmol) was added and stirring was continued at RT for an additional 4 h. The intermediate carbamate was then extracted with Et 2 O, dried over Na 2 SO 4 and concentrated under vacuo to give viscous oil. The oil was taken up in THF (10 ml) and a solution of borane in THF (1M) was added (6.0 ml). The reaction mixture was then heated at 65° C. over night, cooled to RT and carefully quenched with cone. HCl (5 ml). The mixture was then heated at 80° C. for 2 h, cooled to RT, concentrated under vacuo, diluted with Et 2 O (10 ml) and neutralized with an aqueous solution of NaHCO 3 . The organic phases were dried over Na 2 SO 4 and the product purified by flash chromatography (SiO 2 , CH 2 Cl 2 /MeOH 9:1) to afford 0.34 g (70%) of the title compound as a colorless oil. ES-MS m/e: 319.1 (M+H + ).
d)[(3RS,4SR)-1-Benzyl-4-(4-chloro-3-fluoro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine
To a stirred solution of [(3RS,4SR)-1-benzyl-4-(4-chloro-3-fluoro-phenyl)-pyrrolidin-3-yl]-methyl-amine (340 mg, 1.06 mmol) in MeOH (6 ml) was added 3-fluoro-4-trifluoromethyl-benzaldehyde (230 mg, 1.20 mmol). Then a solution of NaBH 3 CN (85 mg, 1.3 mol) in MeOH (1.5 ml) and AcOH (0.01 ml) were added. The reaction mixture was stirred overnight at RT, concentrated under vacuo, diluted with EtOAc, washed with H 2 O. The organic phases were dried over Na 2 SO 4 and the product purified by flash chromatography (SiO 2 , EtOAc/Heptane 1:4) to afford 145 mg (28%) of the title compound as a colorless oil.
e) [(3RS,4SR)-4-(4-Chloro-3-fluoro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine
To a stirred solution of [(3RS,4SR)-1-benzyl-4-(4-chloro-3-fluoro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (145 mg, 0.29 mmol) in CH 3 CN (2 ml) at RT, was added 2,2,2-trichloroethyl chloroformate (0.06 ml, 0.44 mmol). The reaction mixture was stirred at RT for 3 hours, concentrated under vacuo. The residue was dissolved in AcOH (3 ml) and zinc dust (60 mg) was added portion wise over 3 hours. The solvent was evaporated, the residue diluted in EtOAc and the organic phase was washed with an aqueous solution of NaHCO 3 . The organic phase was dried over Na 2 SO 4 , concentrated under vacuo to afford 80 mg (67%) of the tile compound as a colorless oil. ES-MS m/e: 405.3 (M+H + ).
Pyrrolidine VIII-4
[(3RS,4SR)-4-(3-Chloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine
a) (3SR,4RS)-1-Benzyl-3-(3-chloro-phenyl)-4-nitro-pyrrolidine
A solution of N-(methoxymethyl)-N-(phenylmethyl)-N-(trimethylsilyl)methylamine (9.69 g, 41 mmol) in CH 2 Cl 2 (40 ml) was added drop wise, over a 30 minutes period, to a stirred solution of 1-chloro-3-((E)-2-nitro-vinyl)-benzene (0.68 g, 3.37 mmol) and trifluoroacetic acid (0.21 ml) in CH 2 Cl 2 (40 ml) at 0° C. The ice bath was removed, and the solution was stirred at 25° C. for an additional 48 h. It was then concentrated and purification by flash chromatography (SiO 2 , EtOAc/H 1:4) afforded 6.30 g (73%) of the title compound as a colorless oil. ES-MS m/e: 317.1 (M+H + ).
b) (3RS,4SR)-1-Benzyl-4-(3-chloro-phenyl)-pyrrolidin-3-ylamine
To a stirred solution of (3SR,4RS)-1-benzyl-3-(3-chloro-phenyl)-4-nitro-pyrrolidine (6.30 g, 19.8 mmol) in EtOAc (150 ml) was added portion wise SnCl 2 .2H 2 O (22.43 g, 99 mmol). The reaction mixture was then heated at reflux for 4 hours, cooled down to RT and a saturated aqueous solution of NaHCO 3 (500 ml) was added. The salts were filtered off and the product extracted with EtOAc. The organic phases were then dried over Na 2 SO 4 , and concentration under vacuum. A column chromatography (CH 2 Cl 2 /MeOH 95/5) gave 4.47 g (78%) of the title compound as a light yellow oil. ES-MS m/e: 287.0 (M+H + ).
c) [(3RS,4SR)-1-Benzyl-4-(3-chloro-phenyl)-pyrrolidin-3-yl]-methyl-amine
To a solution of (3RS,4SR)-1-benzyl-4-(3-chloro-phenyl)-pyrrolidin-3-ylamine (4.47 g, 16.0 mmol) in THF (50 ml) was added a solution of K 2 CO 3 (4.31 g, 31 mmol) in H 2 O (35 ml). After 10 minutes, ethyl chloroformate (2.97 ml, 31 mmol) was added and stirring was continued at RT for an additional 4 h. The intermediate carbamate was then extracted with Et 2 O, dried over Na 2 SO 4 and concentrated under vacuo to give viscous oil. The oil was taken up in THF (10 ml) and a solution of borane in THF (1M) was added (62 ml). The reaction mixture was then heated at 65° C. over night, cooled to RT and carefully quenched with conc. HCl (5 ml). The mixture was then heated at 80° C. for 2 h, cooled to RT, concentrated under vacuo, diluted with Et 2 O (50 ml) and neutralized with an aqueous solution of NaHCO 3 . The organic phases were dried over Na 2 SO 4 and the product purified by flash chromatography (SiO 2 , CH 2 Cl 2 /MeOH 9:1) to afford 2.68 g (57%) of the title compound as a colorless oil. ES-MS m/e: 301.2 (M+H + ).
d) [(3RS,4SR)-1-Benzyl-4-(3-chloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine
To a stirred solution of [(3RS,4SR)-1-benzyl-4-(3-chloro-phenyl)-pyrrolidin-3-yl]-methyl-amine (2.20 g, 7.31 mmol) in THF (70 ml) was added 4-bromomethyl-2-fluoro-1-trifluoromethyl-benzene (2.25 g, 8.75 mmol) and Et 3 N (1.21 ml, 8.75 mmol). The reaction mixture was stirred overnight at 40° C., concentrated under vacuo, diluted with EtOAc, washed with H 2 O. The organic phase was dried over Na 2 SO 4 and the product purified by flash chromatography (SiO 2 , EtOAc/Heptane 1:3) to afford 2.0 g (57%) of the title compound as a colorless oil.
e) [(3RS,4SR)-4-(3-Chloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine
To a stirred solution of [(3RS,4SR)-1-benzyl-4-(3-chloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (2.0 g, 4.19 mmol) in CH 3 CN (28 ml) at RT, was added 2,2,2-trichloroethyl chloroformate (0.85 ml, 6.3 mmol). The reaction mixture was stirred at RT for 3 hours, concentrated under vacuo. The residue was dissolved in AcOH (25 ml) and zinc dust (800 mg) was added portion wise over 3 hours. The solvent was evaporated, the residue diluted in EtOAc and the organic phase was washed with an aqueous solution of NaHCO 3 . The organic phase was dried over Na 2 SO 4 , concentrated under vacuo to afford 0.90 g (44%) of the tile compound as a light brown oil. ES-MS m/e: 387.2 (M+H + ).
Pyrrolidine VIII-5
[(3RS,4SR)-4-(3-Chloro-phenyl)-pyrrolidin-3-yl]-methyl-(4-trifluoromethyl-benzyl)-amine
a) [(3RS,4SR)-1-Benzyl-4-(3-chloro-phenyl)-pyrrolidin-3-yl]-methyl-(4-trifluoromethyl-benzyl)-amine
To a stirred solution of [(3RS,4SR)-1-benzyl-4-(3-chloro-phenyl)-pyrrolidin-3-yl]-methyl-amine (0.46 g, 1.59 mmol) in THF (15 ml) was added 1-bromomethyl-4-trifluoromethyl-benzene (0.44 g, 1.86 mmol) and Et 3 N (0.155 ml, 1.59 mmol). The reaction mixture was stirred overnight at RT and concentrated under vacuo. The product purified by flash chromatography (SiO 2 , EtOAc/Heptane 1:4) to afford 500 mg (71%) of the title compound as a colorless oil. ES-MS m/e: 459.3 (M+H + ).
b) [(3RS,4SR)-4-(3-chloro-phenyl)-pyrrolidin-3-yl]-methyl-(4-trifluoromethyl-benzyl)-amine
To a stirred solution of [(3RS,4SR)-1-benzyl-4-(3-chloro-phenyl)-pyrrolidin-3-yl]-methyl-(4-trifluoromethyl-benzyl)-amine (500 mg, 1.09 mmol) in CH 3 CN (7 ml) at RT, was added 2,2,2-trichloroethyl chloroformate (0.22 ml, 1.63 mmol). The reaction mixture was stirred at RT for 3 hours, concentrated under vacuo. The residue was dissolved in AcOH (5 ml) and zinc dust (200 mg) was added portion wise over 1 hours. The solvent was evaporated, the residue diluted in EtOAc and the organic phase was washed with an aqueous solution of NaHCO 3 . The organic phase was dried over Na 2 SO 4 and concentrated under vacuo. The product was purified by column chromatography (CH 2 Cl 2 /MeOH: 9/1) to afford 305 mg (76%) of the tile compound as a colorless oil. ES-MS m/e: 369.2 (M+H + ).
Process for preparation of pyrrolidine intermediates of formula XII
Pyrrolidine XII-1
[(3SR,4RS)-3-(4-Chloro-phenyl)-4-methylamino-pyrrolidin-1-yl]-phenyl-methanone
a) (3SR,4SR)-1-Benzyl-3-(4-chloro-phenyl)-4-nitro-pyrrolidine
A solution of N-(methoxymethyl)-N-(phenylmethyl)-N-(trimethylsilyl)methylamine (6.70 g, 28.2 mmol) in CH 2 Cl 2 (100 ml) was added drop wise, over a 30 minutes period, to a stirred solution of 1-chloro-4-((E)-2-nitro-vinyl)-benzene (4.97 g, 27.1 mmol) and trifluoroacetic acid (0.31 g, 2.7 mmol) in CH 2 Cl 2 (150 ml) at 0° C. The ice bath was removed, and the solution was stirred at 25° C. for an additional 48 h. It was then concentrated and purification by flash chromatography (SiO 2 , EtOAc/H 1:4) afforded 6.75 g (79%) of the title compound as a colorless oil.
b) (3RS,4SR)-1-Benzyl-4-(4-chloro-phenyl)-pyrrolidin-3-ylamine
Titanium (IV) chloride (0.36 g, 1.89 mmol) was added drop wise to a suspension of zinc powder (0.25 g, 3.78 mmol) in THF (3 ml). This solution was heated at 68° C. for one hour, then cooled to RT before (3SR,4RS)-1-benzyl-3-(4-chloro-phenyl)-4-nitro-pyrrolidine (0.20 g, 0.63 mmol) in THF (2 ml) was added. The reaction mixture was then stirred at reflux over night. The reaction was cooled to RT, diluted with 300 ml of Et 2 O, washed with an aqueous solution of NaHCO 3 and the organic phases were dried over Na 2 SO 4 . Flash chromatography (SiO 2 , CH 2 Cl 2 /MeOH, 9:1) yielded 0.10 g (57%) of (3RS,4SR)-1-benzyl-4-(4-chloro-phenyl)-pyrrolidin-3-ylamine as a light yellow oil.
c) [(3RS,4SR)-1-Benzyl-4-(4-chloro-phenyl)-pyrrolidin-3-yl]-methyl-amine
To a solution of (3RS,4SR)-1-benzyl-4-(4-chloro-phenyl)-pyrrolidin-3-ylamine (1.86 g, 6.51 mmol) in THF (20 ml) was added a solution of K 2 CO 3 (1.80 g, 13.02 mmol) in H 2 O (15 ml). After 10 minutes, ethyl chloroformate (0.68 ml, 7.16 mmol) was added and stirring was continued at RT for an additional 4 h. The intermediate carbamate was then extracted with Et 2 O, dried over Na 2 SO 4 and concentrated under vacuo to give viscous oil. The oil was taken up in THF (20 ml) and a solution of borane in THF (1M) was added (26 ml). The reaction mixture was then heated at 65° C. over night, cooled to RT and carefully quenched with conc. HCl (5 ml). The mixture was then heated at 80° C. for 2 h, cooled to RT, concentrated under vacuo, diluted with Et 2 O (100 ml) and neutralized with an aqueous solution of NaHCO 3 . The organic phases were dried over Na 2 SO 4 and the product purified by flash chromatography (SiO 2 , CH 2 Cl 2 /MeOH 9:1) to afford 1.51 g (77%) of rac-[(3S,4R)-1-benzyl-4-(4-chloro-phenyl)-pyrrolidin-3-yl]-methyl-amine as a colorless oil.
d)[(3RS,4SR)-1-Benzyl-4-(4-chloro-phenyl)-pyrrolidin-3-yl]-methyl-carbamic acid tert-butyl ester
To a stirred solution of [(3RS,4SR)-1-benzyl-4-(4-chloro-phenyl)-pyrrolidin-3-yl]-methyl-amine (2.75 g, 9.14 mmol) in CH 2 Cl 2 (25 ml) was added Et 3 N (2.50 ml, 18.2 mmol), DMAP (112 mg, 0.91 mmol) and (Boc) 2 O (2.39 g, 10.95 mmol). After one hour at RT, the organic phase was washed with H 2 O, then dried over Na 2 SO 4 . Column chromatography (Heptane/EtOAc:3/1) afforded 2.60 g (71%) of the title compound as a yellow oil. ES-MS m/e: 401.3 (M+H + ).
e) [(3RS,4SR)-4-(4-Chloro-phenyl)-pyrrolidin-3-yl]-methyl-carbamic acid tert-butyl ester
To a stirred solution of [(3RS,4SR)-1-benzyl-4-(4-chloro-phenyl)-pyrrolidin-3-yl]-methyl-carbamic acid tert-butyl ester (1.30 g, 3.20 mmol) in toluene (30 ml) at RT, was added 1-chloroethyl chloroformate (0.53 ml, 4.80 mmol). The reaction mixture was stirred at 90° C. overnight and concentrated under vacuo. The residue was dissolved in MeOH (30 ml) and the reaction mixture was heated at 80° C. for 2 hours. The solvent was evaporated and the crude product was directly used in the next step without further purification.
e) [(3 RS,4SR)-1-Benzoyl-4-(4-chloro-phenyl)-pyrrolidin-3-yl]-methyl-carb amic acid tert-butyl ester
Using the standard amide coupling (general procedure I), 82 mg of the title compound was produce from [(3RS,4SR)-4-(4-chloro-phenyl)-pyrrolidin-3-yl]-methyl-carbamic acid tert-butyl ester and benzoic acid as a white foam. ES-MS m/e: 415.3 (M+H + ).
f) [(3SR,4RS)-3-(4-Chloro-phenyl)-4-methylamino-pyrrolidin-1-yl]-phenyl-methanone
To a stirred solution of [(3RS,4SR)-1-benzoyl-4-(4-chloro-phenyl)-pyrrolidin-3-yl]-methyl-carbamic acid tert-butyl ester (80 mg, 0.19 mmol) in CH 2 Cl 2 (1 ml) was added TFA (0.2 ml). The reaction mixture was stirred at RT for 2 hours, aqueous NaHCO 3 was added until pH=8 and the product was extracted with CH 2 Cl 2 . The combined organic phase were dried over Na 2 SO 4 . Concentration under vacuo gave 64 mg (95%) of the title product as a colorless oil. ES-MS m/e: 315.1 (M+H + ).
Pyrrolidine XII-2
[(3SR,4RS)-3-(4-Chloro-phenyl)-4-methylamino-pyrrolidin-1-yl]-(3,4,5-trimethoxy-phenyl)-methanone
a) [(3RS,4SR)-4-(4-Chloro-phenyl)-1-(3,4,5-trimethoxy-benzoyl)-pyrrolidin-3-yl]-methyl-carbamic acid tert-butyl ester
Using the standard amide coupling (general procedure I), 75 mg of the title compound was produce from [(3RS,4SR)-4-(4-chloro-phenyl)-pyrrolidin-3-yl]-methyl-carbamic acid tert-butyl ester and 3,4,5-trimethoxy-benzoic acid as a white foam. ES-MS m/e: 505.3 (M+H + ).
b) [(3SR,4RS)-3-(4-Chloro-phenyl)-4-methylamino-pyrrolidin-1-yl]-(3,4,5-trimethoxy-phenyl-methanone
To a stirred solution of [(3RS,4SR)-4-(4-chloro-phenyl)-1-(3,4,5-trimethoxy-benzoyl)-pyrrolidin-3-yl]-methyl-carbamic acid tert-butyl ester (75 mg, 0.15 mmol) in CH 2 Cl 2 (1 ml) was added TFA (0.2 ml). The reaction mixture was stirred at RT for 2 hours, aqueous NaHCO 3 was added until pH=8 and the product was extracted with CH 2 Cl 2 . The combined organic phase were dried over Na 2 SO 4 . Concentration under vacuo gave 62 mg (96%) of the title product as a colorless oil. ES-MS m/e: 405.4 (M+H + ).
Pyrrolidine XII-3
4-[(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-methylamino-pyrrolidine-1-carbonyl]-benzonitrile
a) [(3RS,4SR)-1-Benzyl-4-(3,4-dichloro-phenyl)-pyrrolidin-3-yl]-methyl-carbamic acid tert-butyl ester
To a stirred solution of [(3RS,4SR)-1-benzyl-4-(3,4-dichloro-phenyl)-pyrrolidin-3-yl]-methyl-amine (1.00 g, 2.98 mmol) in CH 2 Cl 2 (10 ml) was added Et 3 N (0.83 ml, 5.96 mmol), DMAP (73 mg, 0.59 mmol) and (Boc) 2 O (1.43 g, 6.55 mmol). After one hour at RT, the organic phase was washed with H 2 O, then dried over Na 2 SO 4 . Column chromatography (Heptane/EtOAc:3/1) afforded 0.93 g (71%) of the title compound as a yellow oil. ES-MS m/e: 435.3 (M+H + ).
b) [(3R,4S)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-methyl-carbamic acid tert-butyl ester
To a stirred solution of [(3RS,4SR)-1-benzyl-4-(3,4-dichloro-phenyl)-pyrrolidin-3-yl]-methyl-carbamic acid tert-butyl ester (928 mg, 2.13 mmol) in CH 3 CN (10 ml) at RT, was added 2,2,2-trichloroethyl chloroformate (0.45 ml, 2.13 mmol). The reaction mixture was stirred at RT for 3 hours, concentrated under vacuo. The residue was dissolved in AcOH (5 ml) and zinc dust (400 mg) was added portion wise over 1 hours. The solvent was evaporated, the residue diluted in EtOAc and the organic phase was washed with an aqueous solution of NaHCO 3 . The organic phase was dried over Na 2 SO 4 and concentrated under vacuo to afford 415 mg (98%) of the tile compound as a light yellow oil. ES-MS m/e: 345.2 (M+H + ).
c) [(3RS,4SR)-1-(4-Cyano-benzoyl)-4-(3,4-dichloro-phenyl)-pyrrolidin-3-yl]-methyl-carbamic acid tert-butyl ester
Using the standard amide coupling (general procedure I), 414 mg of the title compound was produce from [(3RS,4S)-4-(3,4-dichloro-phenyl)-pyrrolidin-3-yl]-methyl-carbamic acid tert-butyl ester and 4-cyano-benzoic acid as a white powder. ES-MS m/e: 474.0 (M+H + ).
d) 4-[(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-methylamino-pyrrolidine-1-carbonyl]-benzonitrile
To a stirred solution of [(3RS,4SR)-1-(4-cyano-benzoyl)-4-(3,4-dichloro-phenyl)-pyrrolidin-3-yl]-methyl-carbamic acid tert-butyl ester (414 mg, 0.87 mmol) in CH 2 Cl 2 (8 ml) was added TFA (2 ml). The reaction mixture was stirred at RT for 2 hours, aqueous NaHCO 3 was added until pH=8 and the product was extracted with CH 2 Cl 2 . The combined organic phase were dried over Na 2 SO 4 . Concentration under vacuo gave 302 mg (92%) of the title product as a colorless oil. ES-MS m/e: 374.1 (M+H + ).
EXAMPLE 1
{(3SR,4RS)-3-(4-Chloro-phenyl)-4-[(3,4-dichloro-benzyl)-methyl-amino]-pyrrolidin-1-yl}-phenyl-methanone
Reductive amination according to general procedure III:
Pyrrolidine intermediate: [(3SR,4RS)-3-(4-Chloro-phenyl)-4-methylamino-pyrrolidin-1-yl]-phenyl-methanone (XII-1), Aldehyde: 3,4-Dichloro-benzaldehyde (commercially available),
ES-MS m/e: 475.1 (M+H + ).
EXAMPLE 2
{(3SR,4RS)-3-(4-Chloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-phenyl-methanone
Reductive amination according to general procedure III:
Pyrrolidine intermediate: [(3SR,4RS)-3-(4-Chloro-phenyl)-4-methylamino-pyrrolidin-1-yl]-phenyl-methanone (XII-1), Aldehyde: 3-Fluoro-4-trifluoromethyl-benzaldehyde (commercially available),
ES-MS m/e: 491.3 (M+H + ).
EXAMPLE 3
{(3SR,4RS)-3-(4-Chloro-phenyl)-4-[(3,4-dichloro-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(3,4,5-trimethoxy-phenyl)-methanone
Reductive amination according to general procedure III:
Pyrrolidine intermediate: [(3SR,4RS)-3-(4-Chloro-phenyl)-4-methylamino-pyrrolidin-1-yl]-(3,4,5-trimethoxy-phenyl)-methanone (XII-2), Aldehyde: 3,4-Dichloro-benzaldehyde (commercially available),
ES-MS m/e: 563.2 (M+H + ).
EXAMPLE 4
{(3SR,4RS)-3-(4-Chloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(3,4,5-trimethoxy-phenyl)-methanone
Reductive amination according to general procedure III:
Pyrrolidine intermediate: [(3SR,4RS)-3-(4-Chloro-phenyl)-4-methylamino-pyrrolidin-1-yl]-(3,4,5-trimethoxy-phenyl)-methanone (XII-2), Aldehyde: 3-Fluoro-4-trifluoromethyl-benzaldehyde (commercially available),
ES-MS m/e: 581.2 (M+H + ).
EXAMPLE 5
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-phenyl-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: Benzoic acid (commercially available),
ES-MS m/e: 525.3 (M+H + ).
EXAMPLE 6
4-{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidine-1-carbonyl}-benzonitrile
Coupling according to general procedure II:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Acid chlorid: 4-Cyano-benzoyl chloride (commercially available),
ES-MS m/e: 550.3 (M+H + ).
EXAMPLE 7
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(2-fluoro-3-trifluoromethyl-phenyl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 2-Fluoro-3-trifluoromethyl-benzoic acid (commercially available),
ES-MS m/e: 611.1 (M+H + ).
EXAMPLE 8
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(2,3-difluoro-phenyl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 2,3-Difluoro-benzoic acid (commercially available),
ES-MS m/e: 561.1 (M+H + ).
EXAMPLE 9
3-{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidine-1-carbonyl}-benzonitrile
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 3-Cyano-benzoic acid (commercially available),
ES-MS m/e: 550.3 (M+H + ).
EXAMPLE 10
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(4-trifluoromethoxy-phenyl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 4-Trifluoromethoxy-benzoic acid (commercially available),
ES-MS m/e: 609.1 (M+H + ).
EXAMPLE 11
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-pyridin-3-yl-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: Nicotinic acid (commercially available),
ES-MS m/e: 526.2 (M+H + ).
EXAMPLE 12
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(5-methyl-isoxazol-3-yl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 5-Methyl-isoxazole-3-carboxylic acid (commercially available),
ES-MS m/e: 530.1 (M+H + ).
EXAMPLE 13
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(2-methoxy-phenyl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 2-Methoxy-benzoic acid (commercially available),
ES-MS m/e: 555.2 (M+H + ).
EXAMPLE 14
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-m-tolyl-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 3-Methyl-benzoic acid (commercially available),
ES-MS m/e: 539.3 (M+H + ).
EXAMPLE 15
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(3,5-dimethoxy-phenyl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 3,5-Dimethoxy-benzoic acid (commercially available),
ES-MS m/e: 585.2 (M+H + ).
EXAMPLE 16
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(3,4-dimethoxy-phenyl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 3,4-Dimethoxy-benzoic acid (commercially available),
ES-MS m/e: 585.2 (M+H + ).
EXAMPLE 17
Benzo[1,3]dioxol-5-yl-{(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: Benzo[1,3]dioxole-5-carboxylic acid (commercially available),
ES-MS m/e: 569.2 (M+H + ).
EXAMPLE 18
4-({[(3RS,4SR)-1-(4-Cyano-benzoyl)-4-(3,4-dichloro-phenyl)-pyrrolidin-3-yl]-methyl-amino}-methyl)-2-fluoro-benzonitrile
Reductive amination according to general procedure III:
Pyrrolidine intermediate: 4-[(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-methylamino-pyrrolidine-1-carbonyl]-benzonitrile (XII-3), Aldehyde: 2-Fluoro-4-formyl-benzonitrile (commercially available),
ES-MS m/e: 506.9 (M+H + ).
EXAMPLE 19
4-{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidine-1-carbonyl}-3-fluoro-benzonitrile
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 4-Cyano-2-fluoro-benzoic acid (commercially available),
ES-MS m/e: 568.1 (M+H + ).
EXAMPLE 20
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(2-fluoro-5-methanesulfonyl-phenyl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 2-Fluoro-5-methanesulfonyl-benzoic acid (described in the patent US20060149062),
ES-MS m/e: 621.1 (M+H + ).
EXAMPLE 21
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(5-ethanesulfonyl-2-fluoro-phenyl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 5-Ethanesulfonyl-2-fluoro-benzoic acid (described in the patent WO2006072436),
ES-MS m/e: 635.1 (M+H + ).
EXAMPLE 22
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(4-methanesulfonyl-phenyl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 4-Methanesulfonyl-benzoic acid (commercially available),
ES-MS m/e: 603.1 (M+H + ).
EXAMPLE 23
4-{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidine-1-carbonyl}-2-methyl-benzonitrile
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 4-Cyano-3-methyl-benzoic acid (preparation described in Bioorg. Med./Chem. Lett. 14 (2004) 4585-4589),
ES-MS m/e: 566.1 (M+H + ).
EXAMPLE 24
1-(4-{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidine-1-carbonyl}-phenyl)-ethanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 4-Acetyl-benzoic acid (commercially available),
ES-MS m/e: 567.2 (M+H + ).
EXAMPLE 25
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(6-methyl-pyridin-3-yl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 6-Methyl-nicotinic acid (commercially available),
ES-MS m/e: 540.1 (M+H + ).
EXAMPLE 26
5-{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidine-1-carbonyl}-pyridine-2-carbonitrile
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 6-Cyano-nicotinic acid (commercially available),
ES-MS m/e: 551.1 (M+H + ).
EXAMPLE 27
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(6-morpholin-4-yl-pyridin-3-yl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 6-Morpholin-4-yl-nicotinic acid (commercially available),
ES-MS m/e: 611.2 (M+H + ).
EXAMPLE 28
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(6-fluoro-pyridin-3-yl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 6-Fluoro-nicotinic acid (commercially available),
ES-MS m/e: 546.2 (M+H + ).
EXAMPLE 29
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(6-methoxy-pyridin-3-yl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 6-Methoxy-nicotinic acid (commercially available),
ES-MS m/e: 556.1 (M+H + ).
EXAMPLE 30
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(6-pyrazol-1-yl-pyridin-3-yl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 6-Pyrazol-1-yl-nicotinic acid (commercially available),
ES-MS m/e: 592.1 (M+H + ).
EXAMPLE 31
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-p-tolyl-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 4-Methyl-benzoic acid (commercially available),
ES-MS m/e: 539.2 (M+H + ).
EXAMPLE 32
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(2-morpholin-4-yl-pyridin-4-yl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 2-Morpholin-4-yl-isonicotinic acid (commercially available),
ES-MS m/e: 611.2 (M+H + ).
EXAMPLE 33
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(2-methyl-pyridin-4-yl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 2-Methyl-isonicotinic acid (commercially available),
ES-MS m/e: 542.2 (M+H + ).
EXAMPLE 34
N-(4-{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidine-1-carbonyl}-pyridin-2-yl)-acetamide
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 2-Acetylamino-isonicotinic acid (commercially available),
ES-MS m/e: 583.2 (M+H + ).
EXAMPLE 35
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(2-methoxy-pyridin-4-yl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 2-Methoxy-isonicotinic acid (commercially available),
ES-MS m/e: 556.2 (M+H + ).
EXAMPLE 36
(4-Chloro-phenyl)-{(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 4-Chloro-benzoic acid (commercially available),
ES-MS m/e: 561.1 (M+H + ).
EXAMPLE 37
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(2-fluoro-5-methyl-phenyl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 2-Fluoro-5-methyl-benzoic acid (commercially available),
ES-MS m/e: 557.1 (M+H + ).
EXAMPLE 38
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(4-morpholin-4-yl-phenyl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 4-Morpholin-4-yl-benzoic acid (commercially available),
ES-MS m/e: 609.6 (M+H + ).
EXAMPLE 39
2-(4-{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidine-1-carbonyl}-phenyl)-5-methyl-2,4-dihydro-pyrazol-3-one
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 4-(3-Methyl-5-oxo-4,5-dihydro-pyrazol-1-yl)-benzoic acid (commercially available),
ES-MS m/e: 620.7 (M+H + ).
EXAMPLE 40
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(4-[1,2,4]triazol-1-yl-phenyl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 4-[1,2,4]Triazol-1-yl-benzoic acid (commercially available),
ES-MS m/e: 591.8 (M+H + ).
EXAMPLE 41
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(4-imidazol-1-yl-phenyl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 4-Imidazol-1-yl-benzoic acid (commercially available),
ES-MS m/e: 590.8 (M+H + ).
EXAMPLE 42
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-[4-(1,1-dioxo-1-6-isothiazolidin-2-yl)-phenyl]-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 4-(1,1-Dioxo-1-6-isothiazolidin-2-yl)-benzoic acid (commercially available),
ES-MS m/e: 643.8 (M+H + ).
EXAMPLE 43
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(4-pyridin-2-yl-phenyl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 4-Pyridin-2-yl-benzoic acid (commercially available),
ES-MS m/e: 601.8 (M+H + ).
EXAMPLE 44
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(4-pyridin-3-yl-phenyl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 4-Pyridin-3-yl-benzoic acid (commercially available),
ES-MS m/e: 601.8 (M+H + ).
EXAMPLE 45
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(4-pyridin-4-yl-phenyl)-methanone
Amid coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 4-Pyridin-4-yl-benzoic acid (commercially available),
ES-MS m/e: 601.8 (M+H + ).
EXAMPLE 46
(6-Amino-pyridin-3-yl)-{(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 6-Amino-nicotinic acid (commercially available),
ES-MS m/e: 540.8 (M+H + ).
EXAMPLE 47
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(4-[1,3,4]oxadiazol-2-yl-phenyl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 4-[1,3,4]Oxadiazol-2-yl-benzoic acid (commercially available),
ES-MS m/e: 592.9 (M+H + ).
EXAMPLE 48
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(6-hydroxy-pyridin-3-yl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 6-Hydroxy-nicotinic acid (commercially available),
ES-MS m/e: 542.1 (M+H + ).
EXAMPLE 49
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(2-hydroxy-pyridin-4-yl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 2-Hydroxy-isonicotinic acid (commercially available),
ES-MS m/e: 542.1 (M+H + ).
EXAMPLE 50
(5-Amino-pyridin-2-yl)-{(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 5-Amino-pyridine-2-carboxylic acid (commercially available),
ES-MS m/e: 541.2 (M+H + ).
EXAMPLE 51
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-[1,6]naphthyridin-2-yl-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: [1,6]Naphthyridine-2-carboxylic acid (commercially available),
ES-MS m/e: 577.4 (M+H + ).
EXAMPLE 52
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-pyrimidin-4-yl-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: Pyrimidine-4-carboxylic acid (commercially available),
ES-MS m/e: 527.3 (M+H + ).
EXAMPLE 53
(2-Amino-5-chloro-pyrimidin-4-yl)-{(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzil)-methyl-amino]-pyrrolidin-1-yl}-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 2-Amino-5-chloro-pyrimidine-4-carboxylic acid (commercially available),
ES-MS m/e: 576.8 (M+H + ).
EXAMPLE 54
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-pyrazin-2-yl-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: Pyrazine-2-carboxylic acid (commercially available),
ES-MS m/e: 527.3 (M+H + ).
EXAMPLE 55
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(5-methyl-pyrazin-2-yl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 5-Methyl-pyrazine-2-carboxylic acid (commercially available),
ES-MS m/e: 541.4 (M+H + ).
EXAMPLE 56
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(6-methoxy-pyrazin-2-yl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 6-Methoxy-pyrazine-2-carboxylic acid (commercially available),
ES-MS m/e: 557.4 (M+H + ).
EXAMPLE 57
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(2-methoxy-pyrimidin-5-yl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 2-Methoxy-pyrimidine-5-carboxylic acid (commercially available),
ES-MS m/e: 557.4 (M+H + ).
EXAMPLE 58
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(4-methylamino-phenyl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 4-Methylamino-benzoic acid (commercially available),
ES-MS m/e: 554.4 (M+H + ).
EXAMPLE 59
(3H-Benzotriazol-5-yl)-{(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 3H-Benzotriazole-5-carboxylic acid (commercially available),
ES-MS m/e: 566.4 (M+H + ).
EXAMPLE 60
(3H-Benzoimidazol-5-yl)-{(3SR,4RS)-3-(3,4-dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 3H-Benzoimidazole-5-carboxylic acid (commercially available),
ES-MS m/e: 564.4 (M+H + ).
EXAMPLE 61
N-(4-{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidine-1-carbonyl}-phenyl)-acetamide
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 4-Acetylamino-benzoic acid (commercially available),
ES-MS m/e: 582.4 (M+H + ).
EXAMPLE 62
{(3S,4R)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(3H-imidazo[4,5-b]pyridin-6-yl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 3H-Imidazo[4,5-b]pyridine-6-carboxylic acid (commercially available),
ES-MS m/e: 566.4 (M+H + ).
EXAMPLE 63
4-(5-{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidine-1-carbonyl}-pyridin-2-yl)-piperazine-1-carboxylic acid tert-butyl ester
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 4-(5-Carboxy-pyridin-2-yl)-piperazine-1-carboxylic acid tert-butyl ester (commercially available),
ES-MS m/e: 710.4 (M+H + ).
EXAMPLE 64
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-[6-(1,1-dioxo-1-6-thiomorpholin-4-yl)-pyridin-3-yl]-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 6-(1,1-Dioxo-1-6-thiomorpholin-4-yl)-nicotinic acid (commercially available),
ES-MS m/e: 659.5 (M+H + ).
EXAMPLE 65
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(6-piperazin-1-yl-pyridin-3-yl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 6-piperazin-1-yl-nicotinic acid (commercially available),
ES-MS m/e: 610.5 (M+H + ).
EXAMPLE 66
4-{(3SR,4RS)-3-(4-Chloro-3-fluoro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidine-1-carbonyl}-benzonitrile
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(4-Chloro-3-fluoro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-3), Carboxylic acid: 4-Cyano-benzoic acid (commercially available),
ES-MS m/e: 533.8 (M+H + ).
EXAMPLE 67
{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidin-1-yl}-(4-oxazol-5-yl-phenyl)-methanone
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-1), Carboxylic acid: 4-Oxazol-5-yl-benzoic acid (commercially available),
ES-MS m/e: 592.3 (M+H + ).
EXAMPLE 68
4-{(3SR,4RS)-3-(3,4-Dichloro-phenyl)-4-[methyl-(4-trifluoromethyl-benzyl)-amino]-pyrrolidine-1-carbonyl}-benzonitrile
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3,4-Dichloro-phenyl)-pyrrolidin-3-yl]-methyl-(4-trifluoromethyl-benzyl)-amine (VIII-2), Carboxylic acid: 4-Cyano-benzoic acid (commercially available),
ES-MS m/e: 531.8 (M+H + ).
EXAMPLE 69
4-{(3SR,4RS)-3-(3-Chloro-phenyl)-4-[(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amino]-pyrrolidine-1-carbonyl}-benzonitrile
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3-Chloro-phenyl)-pyrrolidin-3-yl]-(3-fluoro-4-trifluoromethyl-benzyl)-methyl-amine (VIII-4), Carboxylic acid: 4-Cyano-benzoic acid (commercially available),
ES-MS m/e: 516.0 (M+H + ).
EXAMPLE 70
4-{(3SR,4RS)-3-(3-Chloro-phenyl)-4-[methyl-(4-trifluoromethyl-benzyl)-amino]-pyrrolidine-1-carbonyl}-benzonitrile
Amide coupling according to general procedure I:
Pyrrolidine intermediate: [(3RS,4SR)-4-(3-Chloro-phenyl)-pyrrolidin-3-yl]-methyl-(4-trifluoromethyl-benzyl)-amine (VIII-5), Carboxylic acid: 4-Cyano-benzoic acid (commercially available),
ES-MS m/e: 498.0 (M+H + ). | The present invention relates to a compound of formula I
wherein
Ar 1 , Ar 2 , R 1 , R 2 , R 3 , n, o, and p are as described herein or to a pharmaceutically active salt, to all stereoisomeric forms, including individual diastereoisomers and enantiomers as well as to racemic and non-racemic mixtures thereof. Compounds of the invention are high potential NK-3 receptor antagonists for the treatment of depression, pain, psychosis, Parkinson's disease, schizophrenia, anxiety and attention deficit hyperactivity disorder (ADHD). | 2 |
RELATED APPLICATIONS
[0001] This non-provisional application claims the benefit of U.S. Provisional Application No. 60/803,901 filed Jun. 5, 2006.
BACKGROUND
[0002] This specification relates to the networking arts. In one embodiment, its teachings find application in networks that collect data from a plurality of spaced transmitters such as audience response systems.
[0003] Audience response systems typically use a plurality of wired or wireless transmitters to send data, including user responses and/or answers to one or more centrally located receivers. In some networks, it is not important to have particular transmitters associated with particular users. Such anonymous networks include conference settings or generally environments where the collected data itself is of independent value or interest or user anonymity is desired. Occasionally, transmitter licenses expire or software updates are required but this information may not be provided to the network in time to permit that transmitter's data to be accepted in a particular session or until such time as the defect is noticed independently.
[0004] In other networks, it is desirable to maintain a one-to-one correlation of transmitters to users. Such networks include those in the classroom or testing setting where the network is helpful for an instructor or moderator to identify individuals who are participating or who need additional discussion on a particular topic. Often instructors assign an identifiable transmitter to an individual who is then assumed to be the sole user. Then, data collected from that transmitter is attributed to the assigned individual.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] In the accompanying drawings which are incorporated in and constitute a part of the specification, embodiments are illustrated which, together with the detailed description given below, serve to describe exemplary embodiments. It will be appreciated that the illustrated boundaries of elements (e.g. boxes, groups of boxes, or other shapes) in the figures represent but exemplary boundaries. One of ordinary skill in the art will appreciate, for example, that one element may be designed as multiple elements or that multiple elements may be designed as one element. An element shown as an internal component of another element may be implemented as an external component and vice versa. The drawings and components therein are not to any scale. Certain components may be omitted and others shown enlarged to facilitate understanding.
[0006] FIG. 1 is a diagram illustrating an embodiment of a device capable of performing aspects of the present disclosure.
[0007] FIG. 2 is a diagram illustrating an embodiment of a device capable of performing aspects of the present disclosure.
[0008] FIG. 3 is a simplified diagram illustrating communication between devices capable of performing aspects of the present disclosure.
[0009] FIG. 4 is a simplified diagram illustrating communication between devices capable of performing aspects of the present disclosure.
[0010] FIG. 5 is a simplified diagram illustrating communication between devices capable of performing aspects of the present disclosure.
[0011] FIG. 6 is a flowchart illustrating an exemplary method for performing aspects of the present disclosure.
[0012] FIG. 7 is a flowchart illustrating an exemplary method for performing aspects of the present disclosure.
[0013] FIG. 8 is a flowchart illustrating an exemplary method for performing aspects of the present disclosure.
[0014] FIG. 9 is a diagram illustrating embodiments of devices capable of performing aspects of the present disclosure.
[0015] FIG. 10 is a diagram illustrating embodiments of devices capable of performing aspects of the present disclosure.
DETAILED DESCRIPTION
[0016] Generally speaking, one embodiment of a system and method is provided to register transmitters and users in an audience response collecting session. Such a session may include collecting and transmitting real-time, or storing for future transmission, answers, replies, selections, responses or options; to tests, quizzes, polls, queries, surveys, scoring or performance monitoring situations, or opinions. Stimuli for user responses include audio, visual, oral, observed or written interactivity. In one example, system transmitters can include stored user identifying data or transmitters may be adapted to read such data from a machine readable medium in operable connection with the transmitter. Upon initiation of device registration, the transmitter may format a registration package including user identifying data, device identifying data, license information and the like. Once prepared, the transmitter may transmit the package to a response collecting processor for validation and registration.
[0017] FIG. 1 illustrates an example block diagram of a user transmitter device 110 . Preferably the device 110 is adapted to be hand carried and may be operable with a keyboard, keypad, touch sensitive screen, GUI and the like. The device 110 may be controlled by a processing logic 120 that may be in data communication with a first machine readable medium 130 configured to contain operating instructions, for example, embodied as software code. The processor may be in data communication with a second machine readable medium 140 , configured to contain user information such as name, identifying numbers (e.g. social security number, an assigned identifying number, and the like). In addition, the second machine readable medium 140 may also contain license information, operating system version identifiers, historical use information and other desired data.
[0018] It is appreciated that while the description and illustration of two machine readable media are presented for ease of distinction and understanding, the separation may be logical, physical, machine addressable and the like. In other words, the device 110 may have a single memory partitioned or otherwise segregated with operating software in one logical area and user information in another. Alternatively, the device 110 may employ a single internal memory configured to contain an operating system, with a physically separate, internal memory configured to retain the user information. In yet another embodiment, the device 110 may contain an internal memory with operating instructions and an externally connectable memory device such as a memory stick, USB flash memory, magnetic strip and the like with user identifying and licensing data. Variations and combinations of the embodiments discussed, alone or with other known means may be substituted without departing from the teachings here.
[0019] With continued reference to FIG. 1 , the device 110 may also include transceiver 150 configured to communicate signals from the device 110 to a response collection system. The transceiver 150 may communicate using any known means or those later developed such as radio frequency, light, electrical or magnetic signals and may be wireless or wired. The device may also include input/output logic 160 to enable operative communication with peripheral devices including human devices 170 for interaction primarily with the human sensory system and machine devices 180 for interaction primarily with machines. The human devices 170 may include screens, displays, speakers, keypads, keyboard, pointer devices, joysticks and the like. The machine devices 180 may include processors, logic, or other devices for storing, creating, modifying, sending, and/or receiving signals.
[0020] With reference now to FIG. 2 , a response collection system 210 may be controlled by processing logic 220 that may be in data communication with a machine readable medium 230 configured to contain operating instructions, for example, embodied as software code. Machine readable medium 230 may also be configured to store group response software, particular presentations and user registration data, audience responses, statistics and like. The system 210 may also include transceiver 240 configured to receive or exchange signals from a user or participant transmitter. The transceiver 240 may communicate using any known means or those later developed such as radio frequency, light, electrical or magnetic signals and may be wireless or wired. The device may also include input/output logic 250 to enable operative communication with peripheral devices including human devices 260 for interaction primarily with the human sensory system and machine devices 270 for interaction primarily with machines.
[0021] With reference now to FIG. 3 , a user transmitter 310 may initiate a registration process via, for example, manual action such as a combination of key presses or the process may be commenced by automated methods such as upon receipt of a send request, polling request or instruction from a response system. The transmitter 310 formats registration data and sends signals 320 corresponding to the registration data to a receiver 330 in operable connection with a response system 340 . As further discussed below, the response system 340 may then process the registration data. In one embodiment, the registration data may include only a transmitter identifier, so that the response system may uni-directionally receive, or multi-directionally poll or request data from the transmitter when responses are sought. In another embodiment, the registration data may include user identifying information so that responses may be associated with a particular user. In yet another embodiment, registration data may include license information or other data relating to transmitter software.
[0022] Referring now to FIG. 4 , if the registration process succeeds, the transmitter 410 may then participate in an audience response session. During a session, the transmitter 410 occasionally formats a response, such as to a proffered query, and transmits signals 420 corresponding to the response. The transmission can be triggered by a polling request from the response system or by a send request such as user action on the transmitter 410 (e.g. a key press). The response may then be received at a receiver 430 in operable connection with a response system 440 , and processed accordingly.
[0023] Referring now to FIG. 5 , if the registration process fails, the response system 510 may format an invalid registration packet which is transmitted by a transmitter 520 . Signals 530 corresponding to the invalid registration packet are received by a transmitter 540 and processed. In one embodiment, a user may receive an indication that the registration failed and that the user will be unable to participate in the audience response session. In another embodiment, the transmitter disables transmission or completely powers down until the failure is remedied. Such a remedy may be obtaining proper licensing, updating records and the like.
[0024] Referring now to FIG. 6 , in one embodiment a transmitter may format a registration packet 610 including license data such as expiration date, version and the like corresponding to the transmitter software, in this instance embodied as firmware. The packet is communicated to the response processor, for example over a wireless signal communication protocol. The response processor decodes the packet and checks licensing data, 620 . If the license is current, the firmware data, such as firmware version, is checked, 630 . If both the license and firmware checks prove valid, the response processor registers the transmitter, 640 . Optionally, the response processor may then format an acknowledgement data packet 650 for communication to the transmitter. Once received at the transmitter the acknowledgement is decoded if needed, and displayed to the user. The transmitter may then participate in the audience response session, 660 . In the event either the licensing data check 620 or firmware data check 630 are invalid, then the response processor does not register the transmitter, and the transmitter is not able to participate in the audience response session.
[0025] With reference to FIG. 7 , in one embodiment a transmitter may format a registration packet 710 , for example in response to a registration trigger generated either by a user or by a response system. Here, the packet may include data that identifies a user. The user identification data may be loaded into the device or contained on other machine readable media that can be associated with the transmitter only during the registration process or anytime when the transmitter is to be used. The user data may include employee identifiers, student identifiers, or registrant data that may or may not be associated with a particular person. The packet is communicated to the response processor, for example, over a wired signal communication protocol. The response processor decodes the packet and checks user data, 720 . If the data meets acceptance criteria, the response processor causes the transmitter to be registered, 730 . In the user data is determined to be invalid, then the response processor does not register the transmitter, and the transmitter is not able to participate in the audience response session.
[0026] With reference now to FIG. 8 , in one embodiment a transmitter may format a registration packet 810 . The packet may then be communicated to a response processor, for example, using a radio frequency signal communication protocol. The response processor decodes the packet and checks registration data, 820 . Should the registration data not satisfy registration parameters, the response processor may format a participation denial packet, 830 . The denial packet may include an error code or display explaining why participation is denied, and/or may cause the transmitter to become inoperative until the condition is remedied. The packet is communicated to the transmitter, and the device may be disabled from participation, 840 .
[0027] With reference now to FIG. 9 , a transmitter device 910 is shown with logic 920 , for example a USB flash memory device, attached. Logic 920 may contain user identification data, license data and the like, be readable, writable or either selectively. In one embodiment, the logic 920 may be attached for the registration process. Here, internal transmitter logic may read the required data from the logic as needed to prepare a registration packet. After registration, the logic 920 may be removed while the transmitter participates in the audience response session. In another embodiment, the logic 920 may be required to maintain connection to the transmitter 910 to continue participation in the audience response session. In yet another embodiment, the transmitter device may include machine readable media for retaining user and/or licensing data. In this embodiment, the required information may be provided to the machine readable medium specifically over a wireless link, for example, or other peripheral machine device 930 in operable communication with the transmitter 910 . In another embodiment, a user may slide a magnetic strip encoding the desired data through a reader in the transmitter 910 . In yet another embodiment, a user may enter the data in response to prompts or otherwise on the transmitter keypad 940 or other peripheral human device.
[0028] With reference now to FIG. 10 , a transmitter device 1010 is shown with logic 1030 , for example a proximity card in communication. Logic 1030 may contain user identification data, license data, firmware updates and the like. In one embodiment, the logic 1030 may be closely positioned for the registration or update process. Here, logic internal to the transmitter 1010 may read or receive the required data from the logic as needed to prepare a registration packet. After registration, the logic 1030 may be stored while the transmitter participates in the audience response session. In another embodiment, the logic 1030 may be required to maintain communication with the transmitter 1010 to continue participation in the audience response session. In yet another embodiment, the transmitter device may include machine readable media for retaining user and/or licensing data. In this embodiment, the required information may be provided to the machine readable medium specifically over a wireless link, for example, or other peripheral machine device 1030 in operable communication with the transmitter 1010 . In another embodiment, logic 1030 may communicate via wireless 802.11 protocol, for example, through a receiver in the transmitter 1010 . In yet another embodiment, a user may enter the data in response to prompts or otherwise on the transmitter keypad 1040 or other peripheral human device, such as keypad, GUI and the like.
[0029] While the systems, methods, and so on have been illustrated by describing examples, and while the examples have been described in considerable detail, it is not the intention of the applicants to restrict or in any way limit the scope of the appended claims to such detail. It is, of course, not possible to describe every conceivable combination of components or methodologies for purposes of describing the systems, methods, and so on provided herein. Additional advantages and modifications will readily appear to those skilled in the art. Therefore, the invention, in its broader aspects, is not limited to the specific details, the representative apparatus, and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the spirit or scope of the applicants' general inventive concept. Thus, this application is intended to embrace alterations, modifications, and variations that fall within the scope of the appended claims. Furthermore, the preceding description is not meant to limit the scope of the invention. Rather, the scope of the invention is to be determined by the appended claims and their equivalents.
[0030] To the extent that the term “includes” or “including” is employed in the detailed description or the claims, it is intended to be inclusive in a manner similar to the term “comprising” as that term is interpreted when employed as a transitional word in a claim. Furthermore, to the extent that the term “or” is employed in the claims (e.g., A or B) it is intended to mean “A or B or both”. When the applicants intend to indicate “only A or B but not both” then the term “only A or B but not both” will be employed. Similarly, when the applicants intend to indicate “one and only one” of A, B, or C, the applicants will employ the phrase “one and only one”. Thus, use of the term “or” herein is the inclusive, and not the exclusive use. | An audience response system includes a peripheral machine device capable of storing data and input/output circuitry physically connected to the transmitter unit and configured to enable operative communication between the peripheral machine device and the processor logic, where the processor logic disables selected functionality of the transmitter unit until valid data passes from the peripheral machine device and the processor logic. | 7 |
CROSS REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of PCT application of PCT/JP2007/055384, which was filed on Mar. 16, 2007.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to an antenna positioning method and an antenna mounting device for a communication device, and an antenna device.
[0003] Communication devices having a transmission diversity functions, receive diversity functions and MIMO (Multiple Input Multiple Output) communication functions, for performing communication using a plurality of antennas, are available. FIG. 11 is a diagram depicting a receive diversity, showing a space diversity configuration comprised of one transmission antenna ATt and two receive antennas ATr 0 and ATr 1 . If the channel response characteristics between the transmission antenna ATt and each of the two receive antennas ATr 0 and ATr 1 are h 0 and h 1 , noise between the transmission antenna ATt and each of the receive antennas ATr 0 and ATr 1 are n 0 and n 1 , the transmission signal is x 0 and the receive signals of each of the receive antennas ATr 0 and ATr 1 are r 0 and r 1 , then the following expressions are established.
[0000] r 0 =h 0 x 0 +n 0 (1a)
[0000] r 1 =h 1 x 0 +n 1 (1b)
[0004] FIG. 12 is a diagram depicting a maximum ratio combination, where the channel estimation units 1 a 0 and 1 a 1 in branches # 0 and # 1 (receive antennas ATr 0 and ATr 1 ) estimate the channel response characteristics h 0 and h 1 in the branches # 0 and # 1 and output the complex conjugate h 0 * and h 1 * of the channel response characteristics respectively, and channel compensation units 1 b 0 and 1 b 1 multiply the receive signals r 0 and r 1 by h 0 * and h 1 * respectively, and output
[0000] s 0 =h 0 *r 0 (2a)
[0000] s 0 =h 1 *r 1 (2b)
[0000] or output the following respectively.
[0000] s 0 =|h 0 | 2 x 0 +h 0 *n 0 (2a)′
[0000] s 0 =|h 1 | 2 x 0 +h 1 *n 1 (2b)′
[0005] A space diversity combining unit 1 c combines the output of the channel compensation unit 1 b 0 and 1 b 1 of each branch, and inputs the following combined signal to a demodulation unit 1 d.
[0000] s 0 +s 1 =(| h 0 | 2 +|h 1 | 2 ) x 0 +h 0 *n 0 +h 1 *n 1 (2c)
[0000] In the maximum ratio combining method,
[0000] (|h 0 | 2 +|h 1 | 2 )
[0000] becomes a diversity gain.
[0006] In such a communication method using a plurality of antennas, it is necessary to decrease correlation, ideally to none, between the antenna receive signals. In FIG. 11 , for example, if the correlation of the receive signals between the receive antennas ATr 0 and ATr 1 is 1, the receive state becomes worse when the channel response h 0 (=h 1 ) becomes worse, which makes diversity reception meaningless. But if the correlation is 0, then even if one channel response h 0 becomes worse, the other channel response h 1 does not become worst, and a good receive state can be maintained.
[0007] In a case of a communication device which can place a sufficient distance between antennas, the phase characteristics of the receive signal of each antenna change because of the distance difference, and correlation of the receive signals decreases. But in a case of a communication device of which antenna mounting positions are limited, such as a portable telephone, the distance between antennas is not sufficient, and correlation between the antenna receive signals becomes high, and as a result, the diversity function cannot be exerted as much as the case of no correlation, and the radio characteristics, including the error rate, deteriorate.
[0008] A conventional technology on radiation characteristics of an antenna is directional diversity that increases radiation characteristics of an antenna in a direction at which the radiation characteristics of another antenna is low, so that the radiation characteristics of the antennas compensate each other (Japanese Patent Application Laid-Open No. H7-143102), which can decrease correlation. In other words, according to this prior art, the radiation patterns of the two antennas are designed so as to be like petals in a conjugate relationship, as shown in (a) and (b) of FIG. 13 , and one having a greater direct wave or indirect wave is selected.
[0009] However it is difficult to design antennas which have the radiation patterns in FIG. 13 . Also the prior art does not fully consider the relationship of the radio incoming direction or the radio radiation direction and the antenna positions, and therefore the radiation pattern of each antenna is not always used efficiently.
SUMMARY OF THE INVENTION
[0010] In a certain aspect, it is an object of the present invention to decrease correlation between antennas, regardless the radio incoming direction or radio radiation direction.
[0011] In a certain aspect, it is another object of the present invention to decrease correlation between the antenna receive signals even if radio waves come from the direction of a straight line connecting at least two antenna positions.
[0012] Antenna Positioning Method
[0013] A first aspect of the present invention is an antenna positioning method for a communication device that performs communication using a plurality of antennas positioned on a straight line, having: a first step of measuring radiation pattern characteristics of each antenna; a second step of detecting a direction in which fluctuation of the radiation pattern characteristics of each antenna is large; and a third step of positioning each antenna in the communication device so that the direction in which the characteristic fluctuation is large coincides with the straight line direction.
[0014] The second step has a step of calculating a dispersion of the radiation pattern characteristics in a predetermined angle range, for the entire circumference, and a step of deciding a center direction of the angle range in which the calculated dispersion is maximum, as the direction in which the characteristic fluctuation is large.
[0015] The second step has a step of calculating a total of a dispersion of the radiation pattern characteristics in a predetermined first angle range and a dispersion of the radiation pattern characteristics in a second angle range which is shifted from the first angle range by 180°, for the entire circumference, and a step of deciding a center direction of the first angle range in which the calculated total is maximum, as the direction in which the characteristic fluctuation is large.
[0016] The second step has a step of calculating the correlation of the radiation pattern characteristics of a first antenna in a first angle range and radiation pattern characteristics of a second antenna in a second angle range, while changing a combination of the first angle range and second angle range, and a step of determining a combination of the first angle range and second angle range of which correlation is minimum, and judging a center direction of the first angle range as the direction in which the characteristic fluctuation of the first antenna is large, and judging a center direction of the second angle range as the direction in which the characteristic fluctuation of the second antenna is large.
[0017] The second step has a step of calculating the correlation of the radiation pattern characteristics of a first antenna in a first angle range and an angle range shifted from the first angle range by 180° and the radiation pattern characteristics of a second antenna in a second angle range and an angle range shifted from the second angle range by 180°, while changing a combination of the first angle range and second angle range, and a step of determining a combination of the first angle range and second angle range of which correlation is minimum, and judging a center direction of the first angle range as the direction in which the characteristic fluctuation of the first antenna is large, and judging a center direction of the second angle range as the direction in which the characteristic fluctuation of the second antenna is large.
[0018] Antenna Mounting Device
[0019] A second aspect of the present invention is an antenna mounting device for a communication device that performs communication using a plurality of antennas positioned on a straight line, having: a radiation pattern characteristic measurement unit that measures the radiation pattern characteristics of each antenna; a characteristic fluctuation detection unit that detects a direction in which fluctuation of the radiation pattern characteristics of each antenna is large; and an antenna positioning unit that positions each antenna in the communication device so that the direction in which the characteristic fluctuation is large coincides with the straight line direction.
[0020] The characteristic fluctuation detection unit calculates a dispersion of the radiation pattern characteristics in a predetermined angle range for an entire circumference for each antenna, and decides a center direction of the angle range in which the calculated dispersion is maximum, as the direction in which the characteristic fluctuation is large.
[0021] The characteristic fluctuation detection unit calculates a total of a dispersion of the radiation pattern characteristics in a predetermined first angle range and a dispersion of the radiation pattern characteristics in a second angle range which is shifted from the first angle range by 180°, for the entire circumference for each antenna, and decides a center direction of the first angle range in which the calculated total is maximum, as the direction in which the characteristic fluctuation is large.
[0022] The characteristic fluctuation detection unit calculates the correlation of the radiation pattern characteristics of a first antenna in a first angle range and the radiation pattern characteristics of a second antenna in a second angle range, while changing a combination of the first angle range and second angle range, determines a combination of the first angle range and second angle range of which correlation is minimum, and judges a center direction of the first angle range as the direction in which the characteristic fluctuation of the first antenna is large and judges a center direction of the second angle range as the direction in which the characteristic fluctuation of the second antenna is large.
[0023] The characteristic fluctuation detection unit calculates the correlation of the radiation pattern characteristics of a first antenna in a first angle range and an angle range shifted from the first angle range by 180° and the radiation pattern characteristics of a second antenna in a second angle range and an angle range shifted from the second angle range by 180°, while changing a combination of the first angle range and second angle range, determines a combination of the first angle range and the second angle range of which correlation is minimum, and judges a center direction of the first angle range as the direction in which the characteristic fluctuation of the first antenna is large, and judges a center direction of the second angle range as the direction in which the characteristic fluctuation of the second antenna is large.
[0024] Antenna Device
[0025] A third aspect of the present invention is an antenna device in which a plurality of antennas, including a first antenna and a second antenna, are positioned on a straight line. In this antenna device, the first antenna is positioned so that radiation pattern characteristics of the first antenna at a portion crossing with the straight line has a larger change than a change of the radiation pattern characteristics of the first antenna at a portion crossing with a line which passes through the center of the first antenna and is perpendicular to the straight line. The second antenna is positioned so that radiation pattern characteristics of the second antenna at a portion crossing with the straight line has a larger change than a change of the radiation pattern characteristics of the second antenna at a portion crossing with a line which passes through the center of the second antenna and is perpendicular to the straight line.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] FIG. 1 are diagrams depicting the difference of the paths of radio waves which come to two antennas, according to the radio wave incoming direction;
[0027] FIG. 2 are diagrams depicting the principle of the present invention;
[0028] FIG. 3 is a diagram depicting the receive signals of antennas ATR 1 and ATR 2 when the antennas are positioned according to the present invention;
[0029] FIG. 4 is a diagram depicting a first direction decision processing for deciding a direction in which fluctuation is large in the antenna radiation pattern characteristics;
[0030] FIG. 5 is a diagram depicting a second direction decision processing for deciding a direction in which fluctuation is large in the antenna radiation pattern characteristics;
[0031] FIG. 6 is a diagram depicting a third direction decision processing for deciding a direction in which fluctuation is large in the antenna radiation pattern characteristics;
[0032] FIG. 7 is a diagram depicting a fourth direction decision processing for deciding a direction in which fluctuation is large in the antenna radiation pattern characteristics;
[0033] FIG. 8 is a block diagram depicting an antenna mounting device of the present invention;
[0034] FIG. 9 is a flow chart depicting a processing of the antenna mounting device of the present invention;
[0035] FIG. 10 is a diagram depicting an antenna device of the present invention;
[0036] FIG. 11 is a diagram depicting receive diversity;
[0037] FIG. 12 is a diagram depicting maximum ratio combining; and
[0038] FIG. 13 are diagrams depicting a prior art.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0039] (A) FIG. 1 is a diagram depicting a difference of the paths of radio waves which come to two antennas according to the radio wave incoming direction. A direction connecting the positions of the two antennas ATR 1 and ATR 2 is defined as an antenna array direction.
[0040] As (A) of FIG. 1 shows, if two radio waves a and b come at angle θ from the antenna array direction, a difference ΔL between the path difference D 1 in a case where the radio wave a comes to the two antennas ATR 1 and ATR 2 and the path difference D 2 in a case where radio wave b comes to the two antennas ATR 1 and ATR 2 is given by
[0000] Δ L =( D 1 −D 2)= L (1−cos θ)
[0041] (where L is a length between the antennas)
[0000] and is small. If the receive signal at antenna ATR 1 is (a+b), then the receive signal at antenna ATR 2 is approximately (a+b)×α, that is, the correlation of the receive signals at antennas ATR 1 and ATR 2 is 1, which means that correlation is high. α here is a coefficient according to the distance propagation (phase difference) of the path length L.
[0042] On the other hand, if two radio waves c and d come in a direction perpendicular to the antenna array direction, as (B) of FIG. 1 shows, a difference ΔL between the path difference D 1 (=0) when the radio wave c comes to the two antennas ATR 1 and ATR 2 and the path difference D 2 when the radio wave d comes to the two antennas ATR 1 and ATR 2 is given by
[0000] Δ L=D 2 =L ×sin θ
[0043] (where L is a length between the antennas)
[0000] and is large. If the receive signal at antenna ATR 1 is (c+d), then the receive signal at antenna ATR 2 is c+d×β, that is, the correlation of the receive signals at the antennas ATR 1 and ATR 2 is not 1, and correlation is low. β here is a coefficient according to the distance propagation (phase difference) of ΔL.
[0044] In other words, if the radio waves come in the antenna array direction, the change of path difference ΔL is small, compared with the case of the radio waves coming in a direction perpendicular to the antenna array direction, that is, if (a+b) is received by antenna ATR 1 , (a+b)×α is received by antenna ATR 2 . In this case, signals received by the two antennas are approximately the same, and the absolute value of the correlation of the antenna receive signals is 1. In this way, the correlation of radio waves coming from the antenna array direction, of which the change of the path difference ΔL is small, is higher than the that of the radio waves coming in a direction perpendicular to the antenna array directions.
[0045] Therefore if the antenna radiation characteristic values P 1 and P 2 in the antenna array direction AAD of the two antennas ATR 1 and ATR 2 are the same, as shown in (A) of FIG. 2 , the correlation between the antenna receive signals is not improved at all, but is still high. AEP 1 and AEP 2 are the antenna radiation patterns of the antennas ATR 1 and ATR 2 .
[0046] On the other hand, if the antenna radiation characteristic values P 1 ′ and P 2 ′ in the antenna array direction ADD of the antennas ATR 1 and ATR 2 are different, as (B) of FIG. 2 shows, the correlation between the antenna receive signals is improved, and becomes low. In other words, in order to make the correlation in the antenna array direction low, a difference is created between the antenna radiation characteristics of the two antennas ATR 1 and ATR 2 in the antenna array direction. Therefore according to the present invention, the antennas ATR 1 and ATR 2 are positioned so that the direction ranges 11 and 12 , in which fluctuation of the antenna radiation pattern characteristics AEP 1 and AEP 2 is large, are oriented in the antenna array direction AAD.
[0047] FIG. 3 is a diagram depicting the receive signals of the antennas ATR 1 and ATR 2 when the antennas ATR 1 and ATR 2 are positioned so that the directional ranges 11 and 12 , in which the fluctuations of the antenna radiation pattern characteristics AEP 1 and AEP 2 is large, are oriented in the antenna array direction AAD, and two radio waves a and b come at angle θ from the antenna array direction AAD.
[0048] The receive signal of the antenna ATR 1 becomes (a×γ+b×η), because of the influence of the radiation characteristic in the radiation range 11 of the antennas ATR 1 and ATR 2 , and the receive signal of the antenna ATR 2 becomes (a×γ′+b×η′)×α, because of the influence of the radiation characteristics in the radiation ranges 11 and 12 of the antennas ATR 1 and ATR 2 . As a result, the correlation between the receive signals of the two antennas ATR 1 and ATR 2 is improved, and becomes low.
[0000] (B) Control to Decide the Direction in which the Fluctuation of the Antenna Radiation Pattern Characteristics is Large
(a) First Direction Decision Processing
[0049] FIG. 4 is a diagram depicting a first direction decision processing for deciding a direction in which fluctuation is large in the antenna radiation pattern characteristics. In the first direction decision processing, dispersion of the radiation pattern characteristics AEP, in a predetermined angle range θ 1 to θ 2 is calculated for the entire circumference in which a reference direction RD is 0° and a center direction of the angle range in which the dispersion is maximum is decided as the direction in which fluctuation is large in FIG. 3 , so as to match this direction with the antenna array direction AAD. Specifically, the dispersion a of the radiation characteristics of the antenna in a predetermined angle range θ 1 to θ 2 is calculated by the following expression,
[0000]
σ
=
1
θ
2
-
θ
1
∫
θ
1
θ
2
p
(
θ
)
2
θ
-
1
θ
2
-
θ
1
∫
θ
1
θ
2
p
(
θ
)
θ
2
(
1
)
[0000] then the angle range θ 1 to θ 2 is changed for the entire 360° circumference, and the dispersion in each angle range is calculated by Expression (1). Here P(θ) is an antenna radiation characteristic value (complex number) at angle θ. Then the angle range in which the dispersion is maximum is determined, and the center direction in this angle range is decided as the antenna array direction, whereby correlation is decreased.
[0050] The center direction of the angle range in which the dispersion is maximum is determined by Expression (1) for the antennas ATR 1 and ATR 2 respectively, and this direction is decided as the antenna array direction.
(b) Second Direction Decision Processing
[0051] FIG. 5 is a diagram depicting a second direction decision processing for deciding a direction in which fluctuation is large in the antenna radiation pattern characteristics.
[0052] A total dispersion σ of a dispersion σ 1 of the radiation pattern characteristics AEP in a predetermined first angle range θ 1 to θ 2 and a dispersion σ 2 of the radiation pattern characteristics in a second angle range (θ 1 +180 to θ 2 +180), which is shifted from the first angle range by 180°, is calculated by the following expression,
[0000]
σ
=
σ
1
+
σ
2
=
1
θ
2
-
θ
1
∫
θ
1
θ
2
p
(
θ
)
2
θ
-
1
θ
2
-
θ
1
∫
θ
1
θ
2
p
(
θ
)
θ
2
+
1
θ
2
-
θ
1
∫
θ
1
+
180
θ
2
+
180
p
(
θ
)
2
θ
-
1
θ
2
-
θ
1
∫
θ
1
+
180
θ
2
+
180
p
(
θ
)
θ
2
(
2
)
[0000] then the angle range θ 1 to θ 2 is changed for the entire 360° circumference, and the dispersion in each angle range is calculated by Expression (2). Here p(θ) is an antenna radiation characteristic value (complex number) at angle θ. Then the angle range in which the dispersion is maximum is determined, and the center direction in this angle range is determined as the antenna array direction, whereby the correlation is decreased.
[0053] The center direction of the angle range in which the dispersion is maximum is determined for the antennas ATR 1 and ATR 2 respectively by Expression (2), and this direction is decided as the antenna array direction.
(c) Third Direction Decision Processing
[0054] FIG. 6 is a diagram depicting a third direction decision processing for deciding a direction in which fluctuation is large in the antenna radiation pattern characteristics. In the first and second direction decision processings, an angle range in which the dispersion becomes maximum is decided individually for each antenna using Expression (1) or Expression (2), and the center direction thereof is decided as the direction in which fluctuation is large. In the third direction decision processing, however, the direction in which fluctuation is large is decided considering both of the radiation pattern characteristics, AEP 1 and AEP 2 , of the two antennas ATR 1 and ATR 2 at the same time.
[0055] In other words, as (A) of FIG. 6 shows, a correlation λ of radiation pattern characteristics AEP 1 of the first antenna ATR 1 in an angle range θ 1 to θ 2 and the radiation pattern characteristics AEP 2 of the second antenna in the angle range θ 1 to θ 2 is calculated by the following expression.
[0000]
λ
=
1
θ
2
-
θ
1
∫
θ
1
θ
2
p
1
(
θ
)
·
p
2
(
θ
)
θ
(
3
)
[0000] Here p 1 (θ) and p 2 (θ) are the antenna radiation characteristic values (complex numbers) at an angle θ of the first and second antennas respectively. Then in the state shown in (A) of FIG. 6 , the angle range θ 1 to θ 2 of the first antenna ATR 1 and the angle range θ 1 to θ 2 of the second antenna ATR 2 are changed for the entire 360° circumference, by a predetermined angle each time, and the correlation in each angle range is calculated by Expression (3). If the correlation calculation is completed for the entire 360° circumference in the state shown in (A) of FIG. 6 , the radiation pattern characteristics AEP 2 of the second antenna is rotated for a predetermined angle, as shown in (B) of FIG. 6 , and in this state shown in (B) of FIG. 6 , the angle range θ 1 to θ 2 of the first antenna ATR 1 and the angle range θ 1 to θ 2 of the second antenna ATR 2 are changed for the entire 360° circumference by a predetermined angle each time, and the correlation in each angle range is calculated by Expression (3). Hereafter the same correlation calculation is performed by rotating the radiation pattern characteristics AEP 2 of the second antenna by a predetermined angle each time, until rotated 360°.
[0056] While changing a combination of the angle range θ 1 to θ 2 of the first antenna and the angle range θ 1 to θ 2 of the second antenna, correlations of all the combinations are calculated by Expression (3). After the correlation calculation processing ends, a combination of the angle range of the first antenna and the angle range of the second antenna of which correlation is minimum is determined, and the center direction of the angle range of the first antenna of this combination is decided as the direction in which fluctuation is large of the first antenna, and the center direction of the angle range of the second antenna of this combination is decided as the direction in which fluctuation is large of the second antenna. And the correlation is decreased by coinciding the respective center direction with the antenna array direction AAD.
(d) Fourth Direction Decision Processing
[0057] FIG. 7 is a diagram depicting a fourth direction decision processing for deciding a direction in which fluctuation is large in the antenna radiation pattern characteristics.
[0058] A total correlation λ of a correlation λ 1 of the radiation pattern characteristics AEP 1 and AEP in a first angle range θ 1 to θ 2 and a correlation λ 2 of the radiation pattern characteristics AEP 1 and AEP 2 in a second angle range (θ 1 +180 to θ 2 +180), which is 180° from the first angle range, is calculated by the following expression.
[0000]
λ
=
λ
1
+
λ
2
=
1
θ
2
+
θ
1
∫
θ
1
θ
2
p
1
(
θ
)
·
p
2
(
θ
)
θ
+
1
θ
2
-
θ
1
∫
θ
1
+
180
θ
2
+
180
p
1
(
θ
)
·
p
2
(
θ
)
θ
(
4
)
[0000] Then a combination of the angle range θ 1 to θ 2 of the first antenna and the angle range θ 1 to θ 2 of the second antenna is changed in the same way as the third direction decision processing, and the correlations of all the combinations are calculated by Expression (4). After correlation calculation processing ends, a combination of the angle range of the first antenna and the angle range of the second antenna of which correlation is minimum is determined, and the center direction of the angle range of the first antenna of this combination is decided as the direction in which fluctuation is large of the first antenna, and the center direction of the angle range of the second antenna of this combination is decided as the direction in which fluctuation is large of the second antenna. And the correlation is decreased by coinciding the respective center direction with the antenna array direction AAD.
(C) Antenna Mounting Device
[0059] FIG. 8 is a block diagram depicting an antenna mounting device of the present invention, and FIG. 9 is a flow chart depicting a processing of the antenna mounting device. It is assumed that the direction in which fluctuation is large is decided by the first direction decision processing.
[0060] A radiation pattern measurement unit 51 measures the radiation pattern characteristics AEP 1 and AEP 2 of the first and second antennas (e.g. patch antenna) ATR 1 and ATR 2 in a state where the two antennas are mounted in the antenna mounting positions of a portable telephone, for example, and inputs the measured radiation pattern characteristics to an antenna positioning unit 52 (step 101 in FIG. 9 ). A radiation pattern dispersion calculation unit 61 of the antenna positioning unit 52 shifts a predetermined angle range θ 1 to θ 2 for the entire 360° circumference for each antenna, and calculates the dispersion in each angle range by Expression (1). A maximum dispersion range decision unit 62 determines the angle ranges θ 11 to θ 12 and θ 21 to θ 22 of which dispersion is maximum, out of the dispersions calculated by the radiation pattern dispersion calculation unit 61 , for each antenna, and inputs the angle ranges to an antenna positioning direction decision unit 63 (step 102 ). The antenna positioning direction decision unit 63 decides the center directions of the angle ranges θ 11 to θ 12 and θ 21 to θ 22 of each antenna which were input, that is, the directions of θ 1 =(θ 12 −θ 11 )/2, θ 2 =(θ 22 −θ 21 )/2 are decided as the antenna array directions of the two antennas ATR 1 and ATR 2 , and are input to the antenna mounting unit 53 (step 103 ).
[0061] When the antennas ATR 1 and ATR 2 are mounted on a board 71 of a portable telephone, for example, an antenna mounting unit 53 mounts these antennas so that the angle θ 1 and θ 2 , which were input from the antenna positioning direction decision unit 63 becomes the antenna array direction AAD (step 104 ).
[0062] In the above description, the angle θ 1 and θ 2 of the antennas ATR 1 and ATR 2 , to coincide with the antenna array direction AAD, are calculated by Expression (1), but the angles θ 1 and θ 2 of the antennas ATR 1 and ATR 2 , to coincide with the antenna array direction AAD, can also be calculated by Expressions (2) to (4).
[0063] The above example is the case of positioning two antennas, but the present invention can also be applied to the case of positioning three or more antennas.
[0064] In the above description, the case of receiving radio waves was described primarily, but the present invention can also be applied to the case of radiating radio waves.
(D) Antenna Device
[0065] In the antenna device of the present invention, two or more antennas are arrayed on a straight line. In FIG. 3 , two antennas, that is, the first antenna ATR 1 and the second antenna ATR 2 , are arrayed on the straight line. The antenna device of the present invention has the following features. The first antenna ATR 1 and the second antenna ATR 2 are positioned so that respective portions of each antenna having characteristics of which change is largest with respect to the change of an angle among the characteristics of the radiation pattern in the entire range of the circumference, are oriented in the antenna array direction AAD.
[0066] FIG. 10 is another diagram depicting the antenna device of the present invention. In this antenna device, the first antenna ATR 1 and the second antenna ATR 2 are arrayed on the straight line, just like FIG. 3 . The first antenna ATR 1 is positioned so that the characteristics 11 of a portion where the radiation pattern AEP 1 of the first antenna crosses the straight line AAD has a larger change than a change of the characteristics 11 ′ of a portion where the radiation pattern AEP 1 crosses a straight line L 1 which passes through the center of the antenna and is perpendicular to the straight line AAD.
[0067] The second antenna ATR 2 is positioned so that the characteristics 12 of a portion where the radiation pattern AEP 2 of the second antenna crosses the straight line AAD has a larger change than the characteristics 12 ′ of a portion where the radiation pattern AEP 2 crosses a straight line L 2 which passes through the center of the antenna and is perpendicular to the straight line AAD.
EFFECT OF THE INVENTION
[0068] According to the present invention, correlation between antenna receive signals can be decreased regardless the radio wave incoming direction, and as a result, a diversity effect can be implemented.
[0069] Also according to the present invention, correlation between antenna receive signals can be decreased even if the radio waves come in a direction of the straight line connecting at least two antenna positions (antenna array direction). | In an antenna positioning method for a communication device that performs communication using a plurality of antennas positioned on a straight line, the method has a first step of measuring radiation pattern characteristics of each antenna, a second step of detecting a direction in which fluctuation of the radiation pattern characteristics of each antenna is large, and a third step of positioning each antenna in the communication device so that the direction in which the characteristic fluctuation is large matches the straight line direction. | 7 |
CROSS REFERENCE TO RELATED APPLICATION
This is a continuation of applicants' prior application Ser. No. 09/397,741, filed Sep. 16, 1999, which issued Apr. 24, 2001 as U.S. Pat. No. 6,220,722.
BACKGROUND OF THE INVENTION
The invention relates to a LED lamp comprising a gear column, a lamp cap which is connected to an end of the gear column and a substrate which is connected to the other end of the gear column and which is provided with a number of LEDs.
Such a LED (Light Emitting Diode) lamp is known from English patent publication GB 2,239,306, which more particularly describes a LED lamp which can suitably be used for decorative purposes. The known lamp comprises a customary base with a BC cap or a continental screw cap, a gear column which accommodates the electronic gear necessary to operate the LEDs, as well as a substrate which is circularly symmetrical when viewed in the direction of the longitudinal axis of the lamp, in the substrate a number of individual LEDs are incorporated. The colors generated by the different LEDs during operation of the lamp may differ. By using an adjustable switching time control, it is possible to generate specific lighting effects and lighting patterns with the known lamp.
The known lamp has a number of drawbacks. One of these drawbacks is that the lamp can only be used for signaling purposes, whereby the LEDs of the lamp draw attention via a specific adjustable flashing frequency. The known lamp cannot provide for continuous, uniform lighting with a high luminous flux. In addition, the manufacture of the known lamp is relatively complicated. This applies in particular if the known lamp must be provided with a large number of LEDs.
SUMMARY OF THE INVENTION
It is an object of the invention to obviate the above-mentioned drawback. The invention more particularly aims at providing a LED lamp which can be relatively easily mass-produced, and which can be operated such that continuous, uniform lighting with a high luminous flux is obtained.
These and other objects of the invention are achieved by a LED lamp of the type mentioned in the opening paragraph, which is characterized in that the substrate comprises a regular polyhedron of at least four faces, whereby faces of the polyhedron are provided with at least one LED which, during operation of the lamp, has a luminous flux of at least 5 lm, and the gear column is provided with heat-dissipating means which interconnect the substrate and the lamp cap.
The invented lamp enables continuous, uniform, high-intensity lighting to be achieved. It has been found that LEDs having a luminous flux of 5 lm or more can only be efficiently used if the lamp comprises heat-dissipating means. Customary incandescent lamps can only be replaced by LED lamps which are provided with LEDs having such a high luminous flux. A particular aspect of the invention resides in that the heat-dissipating means remove the heat, generated during operation of the lamp, from the substrate via the gear column to the lamp cap and the mains supply connected thereto.
The use of a substrate which is composed of a regular polyhedron of at least four faces enables the intended uniform lighting to be achieved. The regular polyhedron is connected to the gear column, preferably, via a vertex. However, the polyhedron may in principle also be connected to the gear column in the center of one of the faces. The greatest uniformity in lighting is obtained if each one of the faces is provided with the same number of LEDs of the same type.
In experiments leading to the present invention, it has been found that favorable results can be achieved with polyhedrons in the form of an octahedron (regular polyhedron of eight faces) and dodecahedron (regular polyhedron of twelve faces). Better results, however, are achieved with substrates in the form of a hexahedron (polyhedron of six faces, cube). In practice it has been found that a good uniformity in light distribution can already be obtained using substrates in the form of a tetrahedron (regular polyhedron of four faces, pyramid). In an alternative embodiment the substrate comprises a three-dimensional body like a sphere or an ellipsoid, or a pat of a sphere or an ellipsoid.
A favorable embodiment of the LED lamp is characterized in that the lamp is also provided with a (semi-)transparent envelope. This envelope may be made of glass, but is preferably made of a synthetic resin. The envelope serves as a mechanical protection for the LEDs. In addition, the envelope may contribute to obtaining the uniform lighting which can be obtained with the lamp.
A further interesting embodiment of the LED lamp is characterized in that the heat-dissipating means comprise a metal connection between the substrate and the lamp cap. It has been found that such a connection, which may preferably consist of a layer of copper, properly dissipates the heat from the substrate to the lamp cap. In principle, the gear column may entirely consist of a heat-conducting material, for example a metal such as copper or a copper alloy. In this case, it must be ensured that the electronics present in the gear column is properly electrically insulated from the metal gear column. Preferably, also the substrate is made of a metal, such as copper or a copper alloy.
Yet another embodiment of the LED lamp is characterized in that means are incorporated in the column, which are used to generate an air flow in the lamp. Such means, preferably in the form of a fan, can be used, during operation of the lamp, to generate forced air cooling. In combination with the heat-dissipating means, this measure enables good heat dissipation from the gear column and the substrate.
A further embodiment of the invented LED lamp is characterized in that the faces of the polyhedron are provided with an array of LEDs, which preferably comprises at least one green, at least one red and at least one blue LED or at least one green, at least one red, at least one yellow and at least one blue LED or at least one white LED. By virtue of the shape of the substrate, such an array of LEDs can be readily provided, often as a separate LED array, on the faces of the substrate. This applies in particular when the faces of the polyhedral substrate are substantially flat. Such a LED array generally comprises a number of LEDs which are provided on a flat printed circuit board (PCB). In practice, LEDs cannot be readily secured to a substrate which is not level. If LEDs with a high luminous flux (5 lm or more) are used, then a so-called metal-core PCB is customarily used. Such PCBs have a relatively high heat conduction. By providing these PCBs on the (preferably metal) substrate by means of a heat-conducting adhesive, a very good heat dissipation from the LED arrays to the gear column is obtained.
By using one or more LED combinations in the colors green, red and blue or green, red, yellow and blue for each substrate face, a LED lamp can be obtained which emits white light. Such LED combinations composed of three different LEDs are preferably provided with a secondary optical system, in which the above-mentioned colors are blended so as to obtain white light. Another interesting embodiment of the LED lamp is characterized in that the lamp is provided with means for changing the luminous flux of the LEDs. If the gear column is provided with electronics suitable for this purpose, then this measure enables a dimmable LED lamp to be obtained. The dim function is preferably activated by means of an adjusting ring which is attached to the gear column at the location of the lamp cap. It is obvious that, if an envelope is used in the lamp, the adjusting ring must be situated outside the envelope.
A further interesting embodiment of the invented LED lamp is characterized in that the lamp is provided with means for mutually varying the luminous flux of the LEDs provided on the various faces of the substrate. The electronics necessary for this function is incorporated in the gear column of the lamp. By using this measure, it is possible to change the spatial light distribution of the LED lamp. If LEDs of different colors are used, it is also possible to adjust the color and the color distribution of the LED lamp. The distribution of the color and/or light distribution is preferably adjusted via an adjusting ring, which is connected to the gear column at the location of the lamp cap. It is obvious that, if an envelope is used in the lamp, the adjusting ring must be situated outside the envelope.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view of a first embodiment of the invented LED lamp,
FIG. 2 is a view of a second embodiment of the invented LED lamp,
FIG. 3 is a diagrammatic, sectional view of two types of LEDs for use in the invented LED lamp,
FIG. 4 shows an example of a possible application of the invented LED lamp.
It is noted that like parts in the different Figures are indicated by like reference numerals.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows a first embodiment of the invented Light-emitting giode lamp (LED lamp). This lamp comprises a tubular, hollow gear column ( 1 ), which is connected with one end to a lamp cap ( 2 ). The other end of the gear column ( 1 ) is connected to a substrate ( 3 ), which is provided with a number of LEDs ( 4 ). The space within the hollow gear column ( 1 ) accommodates the electronic gear necessary for controlling the LEDs ( 4 ). During operation of the lamp, these LEDs generate a luminous flux of 5 lm or more. The lamp is further provided with an envelope ( 5 ) of a synthetic resin, which envelops the gear column ( 1 ) and the substrate ( 3 ). It is emphasized that despite the presence of the envelope ( 5 ), the effect of the current invention in the LED lamp is achieved.
In the example described herein, the substrate ( 3 ) has the shape of a regular pyramid with four flat faces and is connected to the gear column ( 1 ) via a vertex of the pyramid. The outer surface of the substrate ( 3 ) is made of a metal or a metal alloy, thereby enabling a good heat conduction from the LEDs ( 4 ) to the column ( 1 ). In the present case, the outer surface of the substrate is made of a copper alloy. Each of the faces of the pyramid is provided with a number (five or six) LEDs ( 4 ), which are secured to the faces by means of a heat-conducting adhesive. In this example, single LEDs of the same type are used, which have only one light point per LED (commonly referred to as single-chip LED). Consequently, the LED lamp shown is monochromatic.
The outer surface of the gear column ( 1 ) of the LED lamp is made of a metal or a metal alloy. This enables a good heat conduction from the substrate ( 3 ) to the (metal) lamp cap ( 2 ) to be attained. In the present example, a copper alloy is used for the column. The use of the above-mentioned heat-dissipating means enables the LEDs with the relatively high luminous flux to be used without heat problems in a LED lamp of the above-described type.
The LED lamp shown in FIG. 1 also includes a fan ( 9 ) incorporated in the gear column ( 1 ), which fan generates an air flow during operation of the lamp. This air flow leaves the gear column ( 1 ) via holes ( 6 ) provided in the gear column, and re-enters the gear column via the holes ( 7 ) provided in the gear column. By suitably shaping and positioning the holes ( 6 ), the air flow is led past a substantial number of the LEDs present on the substrate ( 3 ). By virtue thereof, an improved heat dissipation from the substrate and the LEDs is obtained.
FIG. 2 shows a second embodiment of the invented LED lamp. Like the first embodiment, this embodiment comprises a gear column ( 1 ), a metal lamp cap ( 2 ), a metal substrate ( 3 ) with LEDs ( 4 ), an envelope ( 5 ) (not necessary), as well as outlet holes ( 6 ) and inlet holes ( 7 ) for an air flow generated by forced air cooling.
In the example described with respect to FIG. 2, the substrate ( 3 ) is cube-shaped with six flat faces, and is connected to gear column ( 1 ) via a vertex of the cube. The substrate ( 3 ) is made of a metal or a metal alloy, thereby enabling a good heat conduction from the LEDs ( 4 ) to the gear column ( 1 ) to be achieved. In the present case, the substrate is made of a copper alloy. Each one of the faces of the pyramid is provided with a number (eight or nine) LEDs ( 4 ), which are secured to the faces by means of a heat-conducting adhesive. In this example, multiple-chip LEDs are used, which each have three light points (green, red and blue) per LED or four light points (green, red, yellow,blue) per LED. These colors are mixed so as to obtain white light in the secondary optical system of each of the LEDs. Consequently, during operation of the LED lamp shown, white light is obtained.
The LED lamp in accordance with FIG. 2 is also provided with an adjusting ring ( 8 ) for simultaneously changing the luminous flux of the LEDs. By means of this adjusting ring, the lamp can be dimmed as it were. The lamp may also be provided with a second adjusting ring (not shown), by means of which the luminous flux of the LEDs provided on different faces of the substrate can be changed with respect to each other. This measure enables the spatial light distribution of the lamp to be adjusted. The lamp may also be provided with a further adjusting ring (not shown), by means of which the luminous flux of the three light points of each LED can be changed with respect to each other. This measure enables the color of the light emitted by the lamp to be changed.
FIG. 3 is a schematic, sectional view of three types of LEDs ( 4 ) which can suitably be used in the invented LED lamp. FIG. 3-A shows a LED which comprises single-chip LEDs, which each have only one light point ( 11 ) per LED. This light point ( 11 ) is placed on a so-called MC-PCB ( 12 ), which is responsible for a good heat transfer. Light point ( 11 ) is provided with a primary optical system( 13 ), by means of which the radiation characteristic of the LED can be influenced. The LED ( 4 ) is also provided with two electrical connections ( 14 ). Via these connections, the LED is soldered onto the substrate ( 3 ). A heat-conducting adhesive between MC-PCB ( 12 ) and substrate ( 3 ) is responsible for a good heat dissipation from the LED to the substrate.
FIG. 3-B shows so-called multiple-chip LEDs, which each have three light points ( 11 ) (green, red and blue) per LED. If necessary, these three colors are blended so as to obtain white light in the primary optical system ( 13 ) of each one of the LEDs. A better color blending to form white light is obtained if a secondary mixing optics is additionally provided above the multiple-chip LEDs. This situation is shown in FIG. 3-C. Also these multiple-chip LEDs comprise a so-called MC-PCB ( 12 ) and connections ( 14 ).
If single-chip LEDs ( 4 ) in the colors green, red and blue are employed on the substrate ( 3 ), it is convenient to group these LEDs in trios, and provide a further secondary optical system ( 15 ) above the primary optical systems. In this manner, a good color blending of green, red and blue light is obtained. This situation is diagrammatically shown in FIG. 3-D.
FIG. 4 diagrammatically shows an application of a LED lamp, which requires an asymmetric light distribution. The LED lamp ( 20 ) is used as outdoor lighting and is situated on a holder ( 21 ) which is secured to the wall ( 22 ) of a building. The necessary luminous flux in the direction of the wall is much smaller than that in the opposite direction. The asymmetric light distribution required for this purpose can be simply adjusted by means of a LED lamp as described with reference to FIG. 3 .
The LED lamp in accordance with the invention can be readily manufactured and exhibits, during operation of the lamp, a relatively high luminous flux. | An LED lamp has a gear column which is connected between a cap and a substrate. The substrate is provided with a regular polyhedron of at least four planes, the planes having at least one LED which has a luminous flux of at least 5 lm. The gear column also has a heat-dissipater which interconnect the substrate and the lamp cap. | 5 |
PRIORITY CLAIM
This application claims the benefit of previously filed U.S. Provisional Patent Application entitled “COMBINATION CAM LOCK WITH IMPROVED COMBINATION CHANGE MODE,” assigned U.S. Ser. No. 60/859,268, filed Nov. 15, 2006, and which is incorporated herein by reference for all purposes.
FIELD OF THE INVENTION
The present subject matter relates to bi-modal operable locks, namely combination and key operated locks. More particularly, the present subject matter relates to resettable combination locks where knowledge of a current combination as well as possession of a key lock operating key are required to reset the lock combination.
BACKGROUND OF THE INVENTION
Combination and key operated locks have been previously provided in the art and may be employed in a variety of situations to secure enclosed areas or containers. Non-limiting examples may include lockers, rooms, lock boxes, desk drawers, electrical panels, and other similar enclosures. Such locks are convenient from the standpoint that access may be had to a secured item or area by either entering a combination such as by way of manually rotating combination setting elements associated with the lock or by inserting a key into the lock.
Prior United States patents include reference to prior combination and key operated locks. For example, U.S. Pat. No. 6,539,761 to Yang is entitled “Padlock by combining key-operated lock and combination lock” and relates to a padlock which includes a lock body; a shackle operatively locked in or unlocked from the lock body; a key-operated locking device formed in the lock body for operatively unlocking the shackle for unlocking the padlock by using a key, and a combination locking device juxtapositionally formed in the lock body for operatively unlocking the shackle for unlocking the padlock merely by dialing the combination to an unlocking number. U.S. Pat. No. 6,708,534 to Ruan is entitled “Padlock” and relates to a padlock that comprises a shackle, a lock body, a lock cylinder assembly disposed at the middle portion in the lock body, and a combination lock assembly. Such padlock can be operated by either the key or the cipher. Also provided is a padlock having an interchangeable lock cylinder assembly.
Another prior patent is U.S. Pat. No. 6,792,778 by Chen, entitled “Combination lock” and relates to a combination lock comprising a tumbler wheel assembly, a backup locking assembly comprising a keyhole, a shaft, and an inner projection having a half circular section, a pivot assembly having a dog and an engagement member, a push button secured to the pivot assembly, a U-shaped shackle pivotably fastened at the lock housing, and an L-shaped resilient member. A correct combination of tumblers and a subsequent pressing of the push button will disengage the dog from a slot at one leg of the shackle and thus exert an elastic force of the resilient member on the leg for pushing the leg out of engagement with the lock. Should either the combination be forgotten or the combination be changed by another person, a turning of the shaft about 90 degrees by inserting a key into the keyhole will turn the projection and the engaged engagement member for releasing the dog.
U.S. Pat. No. 6,997,023 to Huang is entitled “Combined combination lock and padlock” and relates to a combined combination lock and padlock comprising a second shackle receiving hole including an inside slot at one leg of a shackle of steel rope for receiving a spring depressible block, a tumbler wheel assembly, a key turning assembly, a pivot assembly, a push button, and a U-shaped shackle. A correct combination of tumblers and a subsequent pressing of the push button will disengage a dog with the slot and thus expansion of the block will push the leg out of engagement with the lock. As also stated in U.S. Pat. No. 6,792,778 by Chen, should either the combination be forgotten or the combination be changed by another person, a turning of the shaft about 90 degrees by inserting a key into the keyhole will turn the projection and the engaged engagement member for releasing the dog.
U.S. Pat. No. 7,104,092 to Yu is entitled “Security lock with dual locking means” and concerns a security lock that can be unlocked by the owner of the security lock by dialing an unlocking number or by authorized security personals with a general key. The security lock mainly contains: a lock body, a plugging device, a controlling device, a securing mechanism, a restriction device, a first locking device and a second locking means. The lock body has a first channel and a second channel therein. The plugging device is pluggable into the first channel. The controlling device is slidably secured within the second channel. The securing mechanism is for securing or releasing the plugging device. The restriction device is slidably deposed within the second channel against the controlling device for controlling movement thereof. The first locking device is formed in the lock body for being engaged with or disengaged from the restriction device. The second locking device is formed in the lock body for rotating the restriction device to be disengaged from the first locking device.
U.S. Pat. No. 7,121,123, also to Yu, is entitled “Padlock” and concerns a padlock which comprises a lock body, a shackle, a combination locking device and a key locking device. The shackle is movable relative to the lock body between a locked position and an unlocked position. The combination and key locking devices are installed within the lock body respectively for controlling movements of the shackle. Additionally, the combination locking device has a frame for receiving a first end of the shackle and a combination unit connected to the frame, which is movable when the combination unit is unlock whereby a second end of the shackle is movable to the unlock position. Furthermore, the key locking device comprises a block unit for locking the first end of the shackle and a key unit connected to the block unit, which is movable when the key unit is unlocked by a key.
Depending on the particular use to which the foregoing general types of locks may be applied, it may be convenient or necessary to be able to change the combination for the lock.
In an exemplary known lock structure 100 as illustrated in present FIGS. 1 and 2 , desired access may be had by either inserting a key into the lock or by entering a combination (such as by way of manually rotating combination setting elements). In order to change the combination in the exemplary known combination and key operated locks as illustrated herein in FIGS. 1 and 2 , the currently configured combination must be used to unlock the assembly, with the combination thereafter changed. If the combination is known, the combination may be changed by use of a set screw 110 ( FIG. 1 ) that may be rotated 90° to engage an actuator 112 ( FIG. 2 ) to place the lock in a combination change mode. The combination cannot be changed with possession of a physical unlocking key. Set screw 110 is independent of a dead bolt mechanism that locks the panel cylinder 106 against the cam lock housing as well as independent of the keyplug 104 . In this known arrangement, if the combination is not known and a user tries to change the combination using set screw 110 , set screw 110 will partially rotate but will not allow the combination to be changed. In normal lock operation, the combination may be entered manually and the lock opened by actuation of button 102 .
In light of these recognized deficiencies, there exists a need for a manual combination and key lock operated lock that provides an improved mechanism for resetting the manual combination.
While various implementations of combination and key operated locks have been developed, no design has emerged that generally encompasses all of the desired characteristics as hereafter presented in accordance with the present subject matter.
SUMMARY OF THE INVENTION
In view of the recognized features encountered in the prior art and addressed by the present subject matter, improved apparatus and methodology for permitting reset of a manually enterable lock combination in a manual or physical key operable cam lock have been developed.
In an exemplary configuration and practice of the present subject matter, possession of an appropriately keyed physical key is required to reset a manually enterable combination.
In one of its simpler forms, insertion and operation of a physical key together with entry of a previously configured manually enterable combination allows resetting of the manual enterable combination.
Another positive aspect of the present type of subject matter is that either a physical key or manually entered combination may be used to operate the lock.
In accordance with aspects of certain embodiments of the present subject matter, corresponding methodologies and devices are provided to prevent operation of a lock of the present subject matter due to forced rotation of the keyplug by foreign objects.
One present exemplary embodiment relates to a combination cam lock, comprising a manually operable lock portion, a key lock portion, and a combination change portion. Such manually operable lock portion is preferably configured to enable lock operation upon presentation thereto of a predetermined manual entry combination. Such key lock portion is preferably configured to enable lock operation upon actuation with a physical key, independently of any presentation of any manually entered combination to the manually operable lock portion. Still further, such combination change portion is preferably configured to permit resetting of the predetermined manual entry combination upon both presentation of the predetermined manual entry combination and actuation of the key lock portion with a physical key.
In a present exemplary method of operating a combination cam lock, a combination cam lock is provided having a manually operable combination entry portion operable to open the cam lock upon manual entry of a predetermined combination, and an independently operable physical key operable portion operable to open the cam lock upon rotation of the physical key to a first position thereof. Further in such exemplary method, manual entry is made of the predetermined combination to the manually operable portion so as to unlock the cam lock. Also, a physical key is inserted into the key operable portion, and thereafter such physical key is rotated to a position beyond the first position thereof. Further thereafter, manual entry components of the manually operable combination entry portion may be selectively repositioned, with the result that the predetermined combination may be reset to a new predetermined combination.
In yet another present exemplary methodology, a method of operating a combination cam lock may preferably comprise providing a combination cam lock having a manually operable combination entry portion operable to open the cam lock upon manual entry of a predetermined combination, and an independently operable physical key operable portion operable to open the cam lock upon rotation of the physical key to a first position, with both such portions contained within a housing; manually entering the predetermined combination to the manually operable portion so as to unlock the cam lock; inserting a physical key into the key operable portion, and rotating the physical key to the first position thereof; removing the physical key from the key operable portion; and selectively repositioning manual entry components of the manually operable combination entry portion. With practice of such methodology, the predetermined combination may be reset to a new predetermined combination.
Additional objects and advantages of the present subject matter are set forth in, or will be apparent to, those of ordinary skill in the art from the detailed description herein. Also, it should be further appreciated that modifications and variations to the specifically illustrated, referred and discussed features, elements, and steps hereof may be practiced in various embodiments and uses of the present subject matter without departing from the spirit and scope of the subject matter. Variations may include, but are not limited to, substitution of equivalent means, features, or steps for those illustrated, referenced, or discussed, and the functional, operational, or positional reversal of various parts, features, steps, or the like.
Still further, it is to be understood that different embodiments, as well as different presently preferred embodiments, of the present subject matter may include various combinations or configurations of presently disclosed features, steps, or elements, or their equivalents (including combinations of features, parts, or steps or configurations thereof not expressly shown in the figures or stated in the detailed description of such figures).
Additional embodiments of the present subject matter, not necessarily expressed in the summarized section, may include and incorporate various combinations of aspects of features, components, or steps referenced in the summarized objects above, and/or other features, components, or steps as otherwise discussed in this application. Those of ordinary skill in the art will better appreciate the features and aspects of such embodiments, and others, upon review of the remainder of the specification.
BRIEF DESCRIPTION OF THE DRAWINGS
A full and enabling disclosure of the present subject matter, including the best mode thereof, directed to one of ordinary skill in the art, is set forth in the specification, which makes reference to the appended figures, in which:
FIG. 1 illustrates a known resettable combination and key operable lock structure;
FIG. 2 illustrates a partially broken away view of the known lock structure of FIG. 1 ;
FIG. 3 illustrates a generally front perspective view of a combination and key operable cam lock incorporating features of the present subject matter;
FIG. 4 illustrates a generally front perspective view (in at least partial breakaway view) of a combination and key operable cam lock incorporating features of the present subject matter;
FIG. 5 illustrates a generally rear perspective view (also in at least partial breakaway view) of a combination and key operable cam lock incorporating features of the present subject matter, as otherwise seen in present FIG. 4 ;
FIG. 6 is a perspective view of a combination and key lock illustrating possible unintended operation;
FIG. 7 illustrates a generally front perspective view (in at least partial breakaway view) of a combination and key lock incorporating features of an additional exemplary embodiment of the present subject matter, including features prohibiting unintended lock operation;
FIG. 8 illustrates a generally rear and side perspective view (also in at least partial breakaway view) of a combination and key lock incorporating features of an additional exemplary embodiment of the present subject matter including features prohibiting unintended lock operation, as otherwise seen in present FIG. 7 ;
FIG. 9 illustrates a partially exploded view of another exemplary embodiment of the present subject matter; and
FIG. 10 illustrates a partial see-through view of a portion of the exemplary embodiment illustrated in FIG. 9 .
Repeat use of reference characters throughout the present specification and appended drawings is intended to represent same or analogous features, elements, or steps of the present subject matter.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
As discussed in the Summary of the Invention section, the present subject matter is particularly concerned with an improved methodology for permitting reset of a manually enterable lock combination in a manual combination or physical key operated cam lock.
Selected combinations of aspects of the disclosed technology correspond to a plurality of different embodiments of the present subject matter. It should be noted that each of the exemplary embodiments presented and discussed herein should not insinuate limitations of the present subject matter. Features or steps illustrated or described as part of one embodiment may be used in combination with aspects of another embodiment to yield yet further embodiments. Additionally, certain features may be interchanged with similar devices or features not expressly mentioned which perform the same or similar function.
Referring now to the drawings, FIGS. 1 and 2 (each respectively marked as “Prior Art”) illustrate a known resettable combination and key operable lock structure 100 and a partially broken away view of the lock structure, respectively, as previously described. Such known configuration requires knowledge of the previously set manually enterable lock combination before the combination can be reset regardless of possession of a physical unlocking key. Depending upon the use to which the lock is applied, as previously described, it may not be preferable for possessors of the manually enterable combination to be able to change the combination simply by operation of set screw 110 .
Reference will now be made in detail to presently preferred exemplary embodiments of the subject combination cam lock.
With reference to FIG. 3 , there is illustrated a perspective view of a combination and key operable cam lock 300 incorporating features of the present subject matter and illustrating a fully assembled device. As may be seen, cam lock housing 360 contains therein a keyplug 310 . Cam lock housing 360 may be secured to an item to be protected by way of panel cylinder 362 .
FIGS. 4 and 5 , respectively, illustrate front and rear perspective breakaway views of a cam lock 300 constructed in accordance with a first exemplary embodiment of the present subject matter. In accordance with the present subject matter, knowledge of the previously assigned combination as well as possession of a lock operating key are required to change the combination. The lock operating key may be individually keyed to cam lock 300 or may be a master key for use with a series of similar cam locks. In either circumstance, the key or the combination respectively may be used individually to unlock the assembly.
In accordance with the present subject matter, in order to change the lock combination, insertion of a correct key into keyplug 310 together with knowledge of the current combination is required. As a correct key is inserted into keyplug 310 and rotated 90° clockwise (CW), keyplug 310 turns inside the inner cylinder 320 that encapsulates keyplug 310 and activates a lock plate 340 . Activation of lock plate 340 releases cam lock housing 360 from panel cylinder 362 , thereby unlocking the assembly and allowing the assembly to be rotated 90° CW to an unlatched position.
Detent actuator 370 ( FIGS. 4 and 6 ) prevents inner cylinder 320 from rotating when keyplug 310 is rotated to the unlocked position. In the unlocked position, and if the combination is known and the correct key is inserted into the keyplug 310 and rotated an additional 90° CW, the keyplug 310 rotation stop engages the inner cylinder 320 which rotates inside the cam lock housing 360 with a cam action 322 ( FIG. 6 ) to place the assembly in a combination change mode.
When keyplug 310 and the combination are in a locked position, it could be possible to partially rotate keyplug 310 by inserting a foreign object into keyplug 310 . Even though such activity would be unauthorized (i.e., unintended under ordinary, authorized use) such partial rotation could permit the tumblers in keyplug 310 to engage inner cylinder 320 and to rotate the inner cylinder 320 and keyplug 310 towards the combination change mode position. Such rotation could engage and sufficiently activate lock plate 340 so as to disengage from panel cylinder 362 , thus unlocking the assembly.
With reference now to FIGS. 7 and 8 , it will be seen that, in accordance with an additional embodiment of the present subject matter, measures have been provided to address such potential unauthorized methodology for unintended access to the cam lock mechanism.
With specific and collective reference to FIGS. 7 and 8 , it will be observed that inner cylinder 320 has been formed with a cut out region 324 (see FIG. 7 ), and the cam lock housing 360 has been provided a protrusion 364 (see FIG. 8 ). The provision of cut out region 324 allows three of the five keyplug tumblers 312 , 314 , and 316 , to lock against the cam lock housing 360 instead of against the inner cylinder 320 . As will be understood by those of ordinary skill in the art, by such present arrangement, tumblers one and five (not visible in the drawing) will lock against inner cylinder 320 while tumblers 312 , 314 , and 316 will lock against protrusion 364 of cam lock housing 360 . Inner cylinder cut out 324 and cam lock housing protrusion 364 may be configured so as to allow inner cylinder 320 to rotate 90° CW and back 90° CounterClockwise (CCW). The inner cylinder cutout region 324 and the cam lock housing protrusion 364 are sufficient to prevent the keyplug and inner cylinder from being partially rotated with a foreign object toward combination change mode, thus maintaining the engagement between the lock plate 340 and the panel cylinder 362 and also maintaining the security of the cam lock assembly.
With reference to FIGS. 9 and 10 , a further exemplary embodiment of a combination cam lock generally 400 in accordance with the present subject matter is described. Such further second embodiment provides for resetting the combination of the combination cam lock generally 400 and still advantageously per present subject matter requires both knowledge of the current (or existing) combination and possession of a physical key.
With reference to FIG. 9 , it will be noticed that combination cam lock 400 includes a housing 360 ′ including a portion 320 ′ that has been redesigned to accept keyplug 310 ′ directly without having to provide an inner cylinder (such as inner cylinder 320 of FIGS. 4 and 5 ). Further, keyplug 310 ′, while otherwise generally equivalent to keyplug 310 of the previous embodiment, is provided with a through hole 402 that passes entirely through keyplug 310 ′. In the illustrated embodiment, through hole 402 passes through keyplug 310 ′ in approximate parallel alignment between a second and third tumbler. It should be appreciated that such positioning is exemplary only and may be varied depending on positional requirements with cam lock 400 , for given embodiments thereof. In other words, those of ordinary skill in the art may within the spirit and scope of the present subject matter selectively position such through hole 402 in accordance with the needs or desires of particular implementations.
With further reference to FIG. 9 , it will be seen that cam lock housing 360 ′ is provided with a side hole or opening 404 and a combination change mechanism opening 406 substantially aligned with side hole 404 . Such arrangement is configured so that when keyplug 310 ′ is in place within inner cylinder equivalent space 320 ′ of housing 360 ′, and the lock is unlocked by use of a physical key, keyplug 310 ′ may be rotated 90° from its normal locked position such that keyplug hole 402 , side hole 404 , and combination change mechanism opening 406 are in alignment with each other.
To reset the manual entry combination in the first embodiment of the present subject matter, the correct combination must be set so as to unlock the assembly and a key must be inserted into the keyplug and rotated 180° to activate the inner cylinder 320 ( FIGS. 4 and 5 ) and to place the assembly in “combination change mode”. In the present embodiment, the inner cylinder 320 per se has been eliminated and the assembly housing modified to directly accept keyplug 310 ′ ( FIG. 9 ). In accordance with such further embodiment of the present subject matter, the correct (i.e., existing) combination must be set to unlock the assembly and a key must be inserted into the keyplug 310 ′ and rotated 90° Clockwise to the unlocked position. Maximum keyplug rotation for such further embodiment is 90°.
With the key removed from keyplug 310 ′, a tool such as a large paper clip 420 may then be inserted into side hole 404 ( FIG. 9 ), and through through hole 402 of keyplug 310 ′, and then into combination change mechanism opening 406 that has been provided to expose the combination change mechanism illustrated generally within circle 410 of FIG. 10 . Pushing the combination change mechanism with the tool, allows the combination to be reset. Disengaging the tool from the combination change mechanism sets the new combination. The key may then be reinserted and rotated 90° Counterclockwise to lock the assembly.
It should be appreciated by those of ordinary skill in the art that the keyplug may be provided with any suitable number of tumblers and that the example here illustrated involving three of five tumblers is purely illustrative of the present subject matter, and that different numbers of tumblers (both total and protectively locked) may be alternatively practiced within the broader scope of present aspects of the present subject matter.
While the present subject matter has been described in detail with respect to specific embodiments thereof, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing, may readily produce alterations to, variations of, and equivalents to such embodiments. Accordingly, the scope of the present disclosure is by way of example rather than by way of limitation, and the subject disclosure does not preclude inclusion of such modifications, variations and/or additions to the present subject matter as would be readily apparent to one of ordinary skill in the art. | Disclosed are apparatus and methodology for providing a resettable manual entry combination and key operated cam lock. Methodologies are provided for enabling changing of the manual entry resettable combination given knowledge of the previous combination and possession of an operable key. In alternative embodiments, provisions are made to prohibit forced opening of the lock by way of the use of foreign objects. | 4 |
FIELD OF THE INVENTION
[0001] The disclosed invention applies to the field of assays for detection of analytes, and specifically the field of nucleic acid amplification and detection.
BACKGROUND OF THE INVENTION
[0002] A number of methods are known that enable sensitive diagnostic assays based on nucleic acid detection. Many involve exponential amplification of the nucleic acid target or probe sequences. They include the polymerase chain reaction (PCR), ligase chain reaction (LCR), self-sustained sequence replication (3SR), nucleic acid sequence based amplification (NASBA), strand displacement amplification (SDA), and rolling circle amplification (RCA) Lizardi, et al (1998). Nature Genetics 19:225-232, Lizardi, P. M., & Ward, D. C. (1997) Nature Genetics 16:217-218, Fire, A., & Xu, S-Q. (1995) Proc. Natl. Acad. Sci. USA 92: 4641-4645, Liu, D., et al (1996) J. Am. Chem. Soc. 118: 1587-1594 and Zhang et al (1998) Gene 211: 277-285 and WO 97/19193). All display good sensitivity, with a practical limit of detection of about 10-100 target molecules.
[0003] Accuracy and robustness determine the usefulness of any nucleic acid based assay, particularly when only a few molecules of target are present. It is vital that the process is highly specific. Amplification of untargeted sequences or nontarget directed amplification impacts severely upon assay reliability. Each of the above methods is capable of generating and amplifying non-specific or spurious background signals.
[0004] A frequent source of background amplification in PCR reactions is the hybridisation of a primer to regions of input DNA that share some homology with the targeted sequence. If the 3′ end of a primer has sufficient homology to the untargeted region then it can be amplified in a DNA polymerase reaction. In some instances the resultant, spurious primer extension product may be further amplified. An additional cause of background is attributable to intra- or inter-strand primer annealing, leading to so-called ‘primer-dimer’ artifacts. In extreme cases side reactions can predominate and may totally inhibit or mask amplification of the targeted sequence.
[0005] RCA is applicable to the amplification and detection of specific analytes, such as nucleic acids, proteins and other biomolecules in a sample. Being an isothermal method, RCA, eliminates the need for thermal cycling used in alternative processes such as PCR and, unlike PCR, the target molecule is not amplified. Thus, propagation of polymerase-induced mutations is minimised.
[0006] As already mentioned above, several different formats of rolling circle amplification have been described. The common element is amplification from a small, single stranded, circular DNA probe that is formed via chemical or enzymatic ligation of a linear pre-circle hybridized to a target molecule, Baner J., et al (1998) Nucl. Acids Res. 26: 5073. Ligation of the linear nucleic acid probe generates circular probe molecules proportional in number to the amount of target sequence present in a sample. Rolling circle replication of the circularired probe is an isothermal process mediated via a single primer and a processive, strand-displacing DNA polymerase, resulting in up to 10 4 -fold amplification per hour. The reaction kinetics are linear and hence this process has been termed linear RCA [LRCA].
[0007] In an extension of LRCA additional oligonucleotide primers are employed to replicate the primary, single stranded amplification product. This technique is known variously as hyper-branched, cascade or exponential RCA [ERCA] (Lizardi (supra) and Thomas, et al (1999) Arch. Pathol. Lab. Med. 123: 1170. Here amplification proceeds with geometric kinetics, directing synthesis of branched, double stranded DNA product at rates in excess of 10 9 -fold The first primer hybridises to its complementary region on the probe backbone. In the presence of a strand-displacing DNA polymerase, the primer is extended, eventually displacing itself at its 5′ end once one complete revolution of the circularised probe is made. Continuing polymerisation and strand displacement result in the generation of a long, single stranded, concatameric DNA copy of the original probe circle. This single stranded RCA product, contains binding sites for the second primer. The second primer binds to each tandem repeat of the first strand product. As these multiple priming events elongate, they too initiate strand displacement, in turn creating single-stranded DNA products which expose further binding sites for the first amplification primer. An extensive, hyper-branched structure is built up which contains many replication forks. Self-propagating, strand-displacement results in the release of double stranded DNA fragments from this replication complex. These displaced DNA molecules accumulate as a nested population of fragments displaying sizes that are multiples of the circle unit length.
[0008] RCA probes or pre-circles consist of a linear, 5′-phosphorylated oligonucleotide, usually between 60-120 bases in length. Sequences at the 5′ and 3′ ends of the probe are complementary to the target region such that, when hybridized to its target, the probe ends are juxtaposed. A dual hybridization event combined with the stringent base pairing requirements of a thermostable DNA ligase confers a high degree of target specificity. Located between the target-specific probe arms is a unique sequence that provides binding sites for RCA amplification primers. Probes can be made to distinguish between two alleles that may be present in the target nucleic acid sequence. The terminal 3′ base is varied to complement each of the two possible alleles at the polymorphic site. Probe design and ligation conditions can be optimized to allow allelic discrimination directly in the complex sequence context of genomic DNA without the need for pre-amplification of the target region.
[0009] It is possible to specifically amplify individual circularized probes in a mixture by virtue of their unique backbone sequence. Each probe can be amplified using its specific primer [LRCA] or pair of primers [ERCA]. Amplified probe sequences can be detected and quantified by conventional methods such as fluorescent labels, enzyme-linked detection systems, antibody-mediated label detection, and detection of radioactive labels. One approach, based upon fluorescent detection, utilises Amplifluor™ technology Nazarenko, et al (1997) Nucl. Acids Res. 25: 2516-2521. Amplifluor™ detection primers carry a hairpin stem-loop on their 5′ end, labeled near the base of the stem with a fluorophore and a quencher. In one condition the fluor and quencher are in sufficient proximity for efficient fluorescence quenching to occur. When an Amplifluor™ primer is used as the second ERCA amplification primer, it becomes incorporated into the double-stranded DNA products. As the DNA polymerase copies the Amplifluor™ primer the it unfolds and synthesizes the complement of the stem-loop structure, thus linearizing the sequence and physically separating the fluorophore and quencher and resulting in a fluorescent end product. Use of several Amplifluor™ primers each labeled with a different fluorophore facilitates multiplexed detection in a single RCA reaction.
[0010] One problem affecting RCA reactions is circle-independent or target-independent DNA synthesis. It is reported that one form of circle-independent artifact in dual-primer RCA reactions is reduced by strategies designed to eliminate excess un-ligated probe. For example, in WO 00/36141 Hafner et al suggest that RCA backgrounds can arise from alternative amplification reactions that utilize linear probe molecules.
[0011] We have observed that under certain conditions artifactual RCA products can accumulate to high levels in the absence of circularized probes and or target DNA. The problem is most likely to arise in ERCA reactions containing two primers although, as illustraed herein, non-specific amplification can initiate from a single primer. The likelihood of artifacts increases significantly in multiplex assays utilizing 4 or more different RCA primers. When cloned and sequenced, the circle-independent amplification products are found to be predominantly multimers of head-to-tail primer repeats. In addition to primer sequences, each repeat unit may also contain one or more sequence segments of up to 15 bases not derived from either the target or probe but thought to originate from bacterial DNA contamination commonly associated with commercial sources of molecular biology enzymes.
[0012] Many non-separation based detection strategies will falsely score these products as positive results. It is therefore particularly important for homogeneous assay systems that DNA synthesis does not occur in the absence of legitimate circularized probe molecules.
[0013] The prior art documents several attempts at reducing non-specific events in amplification and hybridization reactions by including various modifications to the primer(s). See for example EP 866071, WO 01/25478, WO 98/13527. These methods exert their effect through increasing the specificity of primer-target interaction, either through lowering Tm by disrupting hydrogen bonding (EP 866071 and WO 98/ 13527) or by shortening the primer but maintaining its Tm using high affinity analogues (WO 01/25478). In EP 866071 modifications are placed within 4-6 bases of the primer 3′ end, within the polymerase footprint, for maximum effectiveness. In contrast, the current invention expressly avoids modifying this region so as not to adversely affect priming efficiency.
[0014] Stump et al (Nucleic Acids Res. 27, 4642-4648 (1999)) have used primers modified with RNA analogues or abasic sites to eliminate artifacts in thermocycled DNA sequencing reactions. The authors demonstrated that such primers could not be used for exponential amplification reactions because after initial extension the DNA polymerase cannot copy the modified primer during subsequent reaction cycles. Whereas Stump et al were unable to show exponential amplification with primers of this design, we show here that primer copying is not an absolute requirement for exponential RCA and that non-replicatable primers can be used effectively to block artifactual amplification in isothermal RCA reactions.
SUMMARY OF THE INVENTION
[0015] This invention improves the sensitivity of nucleic acid based amplification strategies, reducing or eliminating non-specific background signals arising from primer multimers. This is achieved by blocking or impairing the ability of primers to serve as effective templates for DNA synthesis.
[0016] The invention provides a nucleic acid probe or primer, a region of which is modified so as to inhibit or block the molecular interactions that generate primer-based artifacts. In one feature of the invention the modification takes the form of a palindrome that forms a stable hairpin loop structure at the assay temperature. An additional feature is the covalent attachment of chemical moieties such as, but not limited to, dyes. A further modification involves the inclusion of nucleoside analogues within primers.
[0017] The invention also provides methods and reagents that suppress non-specific background amplification.
DETAILED DESCRIPTION OF THE INVENTION
[0018] The invention provides a method of suppressing background signal in an isothermal nucleic acid amplification reaction wherein at least one of the primers used comprises at least one of
[0019] a nucleotide analogue
[0020] a haipin loop at the 5′ end of the primer
[0021] a ribonucleotide
[0022] a fluor or quencher.
[0023] Another aspect of the invention for suppressing background signal in a nucleic acid amplification reaction requires the presence in at least one of the primers of at least two of
[0024] a nucleotide analogue
[0025] a hairpin loop at the 5′ end of the primer
[0026] a ribonucleotide
[0027] a fluor or quencher.
[0028] Non-specific amplification is a problem in nucleic acid amplification schemes that utilize one or more oligonucleotide primers. A mechanism of non-specific amplification has been identified in RCA reactions that is independent of legitimate circular probe molecules and will also arise in the absence of linear probe and target molecules. This type of artifactual DNA synthesis generates a nested set of predominantly double stranded DNA molecules ranging between 50 base pairs to more than 20 kilobase pairs in size and forming a characteristic ladder of products that is frequently indistinguishable from that of a genuine, circle-mediated RCA reaction. DNA sequence analysis of the non-specifically amplified material suggests that it may originate due to a continuous series of self-propagating strand displacement and primer extension events. A single primer, four deoxynucleoside tiphosphates and a DNA polymerase are sufficient to support the synthesis of several micrograms of high molecular weight DNA in a 1-2 hour isothermal reaction. No probe molecules or added target molecules are necessary for non-specific amplification to occur.
[0029] A robust and reliable nucleic acid amplification assay hinges upon the principle that no product is formed in the absence of a specific target molecule. Hence it is vital to prevent non-specific amplification of the type described.
[0030] One aspect of the invention is to provide a method for suppressing the synthesis of non-specific products in a nucleic acid amplification reaction. This is accomplished without reducing the generation of specific targeted products. In this way the signal to noise ratio, sensitivity and reliability of the method are increased.
[0031] In particular, the invention provides a method of RCA in which background DNA synthesis due to non-specific amplification is inhibited when circular probe molecules are not present The invention is useful in all modes of RCA including single primer, dual primer and multiple primer amplification reactions.
[0032] In one embodiment non-specific amplification is inhibited by the use of one or more oligonucleotide primers that contain at least one nucleotide analogue. In LRCA and ERCA it is not essential for the complement of a primer to be made in order for the amplification reaction to be sustained. Thus analogues which render the primers poor templates for polymerase enzymes can be employed to suppress primer self-amplification. Suitable analogues may be positioned at any point in the primer sequence but preferably the 6 positions closest to the 3′ terminus should be unmodified so as not to impact priming efficiency. Examples of nucleotide analogues and related modifications that have been found to be effective include, but are not limited to, locked nucleic acid bases [LNA] (Singh et al (1998) Chem. Commun. 455-456), 2′-O-Methyl RNA bases, substituted 5-nitroindole (WO97/28176), abasic sites and RNA. Single or multiple sites may be modified In certain instances it is desirable to modify adjacent or consecutive bases in order to minimise polymerase read-though. As polymerases differ in their ability to copy templates bearing nucleoside analogues it is necessary to determine empirically the optimal type position and frequency of modified bases. Examples of polymerases that may be used include, but are not limited to, phi 29 DNA polymerase, ThermoSequenase™ II, delta, Thermoanaerobacter thermohydrosulfuricus DNA polymerase, Bst DNA polymerase, Phi 29 DNA polymemse and Sequenase™ T7 DNA polymerase. Preferably Bst DNA polymerase or Phi 29 DNA polymerase are used.
[0033] In a further embodiment, non-specific amplification may be inhibited by the use of one or more oligonucleotide primers with a 5′ region capable of intra-strand base pairing in such a way as to form a duplex stem and loop structure. Suitable primers are composed of four contiguous sequence elements S1, S2, S3 and S4. S1 being at the 5′ terminus and S4 at the 3 terminus of the primer. S1 is the reverse complement of S3. S2 is a spacer region. S4 may be either complementary to or identical to a region of the circular probe molecule. Preferably S1 and S3 are between 4-12 bases long. S2 should be greater than 3 bases long, preferably 5-20 bases long. S4 is of a length calculated to provide a T m equal to the temperature of the amplification reaction. The sequences of S1, S2 and S3 are chosen such that the ΔG of the desired secondary structure is suitably at least 6 kCal and more preferably at least 10 kCal greater than that of any alternative structure. Established guidelines for designing primers for use in nucleic acid amplification reactions are followed in addition to the specific requirements detailed here. Non-specific amplification by ThermoSequenase™ II in dual primer RCA reactions was inhibited when one of a pair of primers carried a 5′ hairpin as described. The same primers lacking a hairpin synthesized large amounts of high molecular weight artifacts under identical conditions. Additionally, ThermoSequenase II was unable to amplify background by RCA in the presence of a single primer when that primer carried a 5′ hairpin. Non-specific RCA by Bst DNA polymerase using a single hairpin primer was not suppressed but it was found that if a fluorophore and fluorescence-quenching moiety were coupled to the same hairpin primer then non-specific amplification was suppressed. Accordingly, this invention also provides a method for inhibiting non-specific amplification by use of primers having the structure of Amplifluor™ primers Nazarenko et al (supra). Fluorophores that have been found useful in this regard include, but are not limited to, 6-FAM Fluorescein, Cy3 and TET. Quenchers that may be used include DABCYL, DABSYL and Methyl Red.
[0034] In yet a further embodiment, non-specific amplification can be suppressed during dual and multiple primer ERCA by use of a linear or a hairpin primer bearing nucleotide analogues in combination with an Amplifluor™ primer bearing nucleotide analogues.
[0035] Although the examples cited here reference RCA, it will be appreciated that alternative amplification schemes such as SDA and LAMP (Notomi, et al (2000) Nucl. Acids Res. 28: (12) e63) that utilize similar DNA polymerases and primers in isothermal conditions may exhibit similar modes of non-specific amplification to the type described This invention is thus equally applicable to these techniques.
[0036] It is anticipated that the invention is also applicable to any nucleic acid amplification method in which copying of primer molecules by a polymerase enzyme may contribute to non-specific amplification and thereby leading to spurious reaction products.
EXAMPLES
Example 1
Non-Specific Amplification.
[0037] DNA polymerases can synthesise double-stranded, high molecular weight DNA under isothermal conditions if given just primers and the four common deoxynucleoside triphosphates (dATP, dCTP, dGTP and dTTP).
[0038] 20 μl reactions containing 20 mM Tris-HCl pH 8.8, 0.1% v/v Triton X-100, 10 mM KCl, 2 mM MgSO 4 , 400 μM dNTP, 8 units Bst DNA polymerase [New England Biolabs] and 1 μM primer were incubated at 60° C. for 90 minutes. Ficoll/Orange-G loading dye was added to each reaction and 10 μl was run on a 2% high resolution agarose gel [Sigma A-4718] in 90 mM Tris-Borate/EDTA buffer pH8.3 for ˜1.5 hours at 150 volts. The gel was stained in a 1:20,000 aqueous dilution of Vistra Green [Amersham Pharmacia Biotech] for 15 minutes then scanned on a Molecular Dynamics FluorImager-595 using 488 nm excitation and 530 nm emission filters.
[0039] A spectrum of DNA products was generated from primers and dNTPs alone by Bst DNA polymerase. The results showed a ladder pattern with approximately 40 bp periodicity when the reaction contained both primers #1 and #2. When reactions contained only primer #1 or primer #2, a complex series of fragments was made, which range from primer length to material so large that it does not enter the gel. Reactions with Bst DNA polymerase and dNTPs only (no primers) did not produce high molecule weight product. Reactions containing primers #1 or #2 and dNTPs but no polymerase again did not produce high molecule weight product.
Example 2
Suppression of Non-Specific Amplification by Primers Containing LNA.
[0040] As the number of different primers in an RCA reaction rises so the risk of non-specific amplification increases. Duplex ERCA reactions were carried out in which each reaction contained two distinct pre-formed circular DNA probe molecules. Two unique, specific RCA primers were included for each circular DNA. One of each pair of primers was an Amplifluor™ primer and the other was either a linear DNA primer or a DNA/LNA chimeric primer.
[0041] Serial dilutions containing both gel-purified, circularized probes were amplified by ERCA for 2 hours at 65° C. in a 20 μl reaction containing 20 mM Tris-HCl pH 8.8, 0.1% v/v Triton X-100, 10 mM KCl, 10 mM (NH4) 2 SO 4 , 2 mM MgSO 4 , 400 μM dNTP, 8 units Bst DNA polymerase, 0.4 μM FAM-dabcyl Amplifluor primer #3, 0.3 μM Cy3-dabcyl Amplifluor primer #4 and either 0.4 μM DNA primers #5 and #6 or 0.4 μM LNA/DNA chimeric primers #7 and #8.
[0042] After ERCA, 2 ul of tracking dye [50% w/v Ficoll F400, 1% w/v Orange-G, 50 mM EDTA] was added and the samples were electrophoresed on a 3% high-resolution agarose gel in 90 mM Tris-borate/EDTA buffer for 2½ hours at 125 volts. The gel was scanned twice in a Molecular Dynamics FluorImager 595 using an excitation wavelength of 488 nm and recording emission a both 530 nm and 570 nm. The two individual colour images were overlaid.
[0043] The gel was then stained by immersion in a 1:20,000 aqueous dilution of Vistra Green and re-scanned with 488 nm excitation and 530 nm emission filters to visualise both fluorescently labelled and unlabelled DNA products.
[0044] Reactions containing 10 6 , 10 5 , 10 4 , 10 3 , 10 2 , 10 1 , 10 0 , or 0 circles were performed with either DNA primers or with LNA/DNA chimeric primers of identical base sequence.
[0045] When 10 5 or more circular probe molecules were present all reactions gave the expected fluorescent-labelled product ladders. At 10 4 copies of circular probe and below, both non-specific fluorescent and non-fluorescent amplification products appeared in those reactions that had DNA primers only. Reactions amplified in the presence of DNA/LNA primers showed no non-specific fluorescent or non-fluorescent ladders—only correct fluorescent products were formed.
Example 3
Suppression of Non-Specific Amplification by Primers Containing RNA.
[0046] Most DNA polymerases have minimal detectable levels of reverse transcriptase activity. Modes of non-specific amplification dependent upon primer copying in RCA reactions can be significantly reduced or eliminated where RCA primers are comprised wholly, or partly, of RNA.
[0047] 30 μl ligation reactions were prepared containing 20 mM Tris-HCl pH8.3, 25 mM KCl, 10 mM MgCl 2 , 0.01% v/v Triton X-100, 1.5 mM NAD + , 100 nM open circle probe, 1 unit Tth DNA ligase and 10 3 , 10 5 or 10 7 molecules of a PCR-amplified DNA target molecule. Reactions were denatured at 95° C. for 3 minutes then incubated at 65° C. for 60 minutes and cooled to 4° C.
[0048] {fraction (1/10)} th of each ligation reaction was subjected to ERCA in 20 μl containing 200 mM Tris-acetate pH 8.5, 1% v/v Triton X-100, 100 mM (NH 4 ) 2 SO 4 , 400 μM dNTP, 8 units Bst DNA polymerase, 0.4 μM FAM-dabcyl Amplifluor primer #3, 0.3 μM Cy3-abcyl Amplifluor primer #4 and either 0.4 μM DNA primers #5 and #6 or 0.4 μM RNA primers #9 and #10. Reactions were incubated for 90 minutes at 65° C. Gel analysis and imaging were as described in Example 2.
[0049] ERCA reactions containing DNA primers showed the anticipated fluorescent amplification products when 10 7 PCR target molecules were used for probe ligation and circularization. No fluorescent signal was seen for 10 5 or 10 3 target molecules. In addition, all reactions with DNA primers generated substantial amounts of non-specific, non-fluorescent material.
[0050] Reactions that contained RNA versions of DNA primers showed no non-specific or non-fluorescent products. RNA primers gave only specific fluoreccent product ladders in both 10 7 and 10 5 target copies. Control ERCA reactions having no targets no DNA ligase or no ligase reaction added were negative as expected.
[0051] RNA primers suppressed non-specific background amplification but did not inhibit rolling circle amplification of circular probe molecules.
Example 4
Suppression of Non-Specific Amplification by a Primer With a 5′ End Hairpin Loop.
[0052] It was found that non-specific amplification involving primer copying in a dual primer reaction could be suppressed if one of the primers has a 5′ end hairpin loop and the reaction is carried out with ThermoSequenase™ II DNA polymerase.
[0053] 30 μl reactions were prepared containing 30 μM each RCA primer, 250 mM Tris-acetate pH8.0, 17.5 mM magnesium acetate, 125 mM potassium glutamate, 5% v/v glycerol, 8 nM dNTPs and 20 units of ThermoSequenase™ II. Reactions were heat denatured at 95° C. for 3 minutes and then incubated for 60 minutes at 68° C. Amplification products were analysed on gels as described in Example 1. Reactions contained two primers #11 and #12, #11 and #13, #1 and #2, #14 and #15, #1 and #16, or #14 and #17.
[0054] Reactions with pairs of linear primers resulted in a 50 base pair ladder of non-specific amplification products. Substitution of one member of a pair of linear primers by one of identical priming sequence plus a 5′ hairpin structure (8 base pair stem and 5 base unpaired loop) prevented non-specific amplification.
Example 5
Suppression of Non-Specific Amplification by Primers Containing Substituted 5-Nitroindole Base Analogues
[0055] 5-amino-pentanoic acid{4-[1-(4-hydroxy-5-hydroxymethyltetrahydrofuran-2-yl)-5-nitro-1H-indol-3-yl]-butyl}-amide, a 5-nitroindole base analogue with a C 6 spacer arm at the 3 position was synthesized as a phosphoramidite by methods described in WO97/28176. It was shown that DNA polymerases are unable to read past this base analogue when it is present in a single stranded DNA template. DNA primers containing substituted 5-nitroindole were prepared and their ability to suppress non-specific amplification was demonstrated.
[0056] Experiments were carried out according to the method outlined in Example 1. Reactions containing a single unmodified primer produced a characteristic ladder of artifactual products. In the presence of a primer (either linear or with a 5′ hairpin) that was modified internally with a single substituted 5-nitroindole six bases from the 3′ terminus, no non-specific amplification was observed.
Example 6
Suppression of Non-Specific Amplification by an Amplifluor Primer
[0057] A region corresponding to the putative nucleotide (ATP)-binding folds of the Human cystic fibrosis gene was PCR-amplified using primers 11i-5 and 11i-3 (sequences #18 and #19) as described by Kerem, B-S. et al, Proc. Natl. Acad. Sci. USA. 87: 8447.
[0058] A series of 20 μl ligation reactions were set up containing from 10 9 -10 5 copies of homozygous normal or homozygous G542X mutant PCR fragment, 10 nM G542X open circle probe (sequence #20), 20 mM Tris-HCl pH8.3, 25 mM KCl, 10 mM MgCl 2 , 0.01% v/v Triton X-100, 1.5 mM NAD + and 1 unit Tth DNA ligase. After heat denaturation at 95° C. for 3 minutes ligation mixes were incubated for 60 minutes at 65° C.
[0059] 30 μl ERCA reactions contained 2 μl ligation mixture, 20 units ThermoSequenase™ II, 250 mM Tris-acetate pH8.0, 17.5 mM magnesium acetate, 125 mM potasium glutamate, 5% v/v glycerol, 8 mM dNTPs, 30 μM primer #1 and either 30 μM primer #2 or 30 μM Amplifluor™ primer #21. Samples were heated to 95° C. for 3 minutes and then incubated at 68° C. for 60 minutes. Gel analysis and imaging were as described in Example 2.
[0060] Open circle probe was ligated in the presence of either matched or mismatched PCR target DNA. Matched means that the open circle probe is the exact complement of the target and that ligation should occur. Mismatched indicates that little or no ligation and amplification should take place. Target DNA was present at 10 9 , 10 7 and 10 5 copies per ligation. Circularized probes were amplified by ERCA using Thermosequenase™ II at 68° C. for 60 minutes. Reactions contained both one linear and one Amplifluor™ primer or two linear RCA primers. For linear primers, there was substantial non-specific amplification with matched probe/target combinations below 10 9 target copies and in all mismatched reactions. Substitution of the linear primer for an Amplifluor™ primer completely inhibited background amplification, leaving only a ladder of specific products. The Amplifluor™ reaction products are larger due to the increased primer length and appear blurred on native agarose gels due to unresolved secondary structures.
7
Suppression of Non-Specific Amplification by a Combination of Amplifluor Primers and Analogue-Modified 5′ Hairpin Primers.
[0061] Whereas a 5′ hairpin structure was sufficient to block non-specific amplification of a single primer by ThermoSequense II it was not effective for Bst DNA polymerase. However, Bst DNA polymerase was unable to amplify a single primer when, in addition to a 5′ hairpin, the priming region contained one or base modifications that prevented read through by the enzyme. Modifications found to be effective included abasic sites and substituted 5-nitroindole. Individual Amplifluor primers, without base modifications, were also refractory to amplification by Bst polymerase.
[0062] When two or more primers were combined non-specific amplification could be prevented only if (1) both carried a hairpin and modified bases or (2) if the first carried a hairpin and modified bases and the second was an Amplifluor primer or (3) if both primers were Amplifluor primers.
[0063] Primer #14 was an unmodified linear primer, primer #22 had the same sequence but with an abasic site 6 bases from the 3′ terminus and primer #23 was similar to #22 but with the addition of a 5′ end hairpin. Primer #25 was an Amplifluor primer. Amplification reactions and gel analyses were as described in Example 1.
[0064] Separate reactions utilizing
[0065] primers #14 and #25.
[0066] primers #22 & #25.
[0067] primers #23 & #25.
[0068] primers #24 & #25.
[0069] primers #16 & #25.
[0070] no primers, Bst DNA polymerase and dNTPs only.
[0071] primers #16 & #17, linear primers only.
[0072] primers and dNTPs only, no Bst DNA polymerase.
[0073] were performed. Apart from the two negative controls only one reaction failed to generate any non-specific amplification products. This reaction contained one hairpin primer modified at position -6 with an abasic site and one FAM-dabcyl Amplifluor primer,
[0074] Non-specific primer pair amplification in dual primer ERCA reactions involving a strand displacing DNA polymerase can be reduced if each of the primers has either a 5′-end hairpin plus base analogues in the priming region or is an Amplifluor primer.
!Sequences? #1 5′ CAGCTGAGGATAGGACATTCGA #2 5′ TCAGAACTCACCTGTTAGACG #3 5′ FAM-ATCAGCACCCTGGCTGAtCTTAGTGTCAGGATACGG t = dabsyl-dT #4 5′ Cy3-ATCAGCACCCTGGCTGAtTAGTACGCTTCTACTCCCTCTTG t = dabsyl-dT #5 5′ ACTAGAGCTGAGACATGACGAGTC #6 5′ ACGACGTGTGACCAGTCAACAT #7 5′ ACTAGAGCtgaGACATGACGAGTC lower case letters are LNA bases #8 5′ ACGACGTGtgaCCAGTCAACAT lower case letters are LNA bases #9 5′ acuagagcugagacaugacgaguc lower case letters are RNA bases #10 5′ acgacgugugaccagucaacau lower case letters are RNA bases #11 5′ CCGTGCTAGAAGGAAACACGC #12 5′ GTACCGCAGCCAGTC #13 5′ TATATGATGGTACCGCAG #14 5′-CCGTGCTAGAAGGAAACACGC #15 5′-TATATGATGGTACCGCAGCCAG #16 5′ ACGATGACTGACGGTCATCGTTCAGAACTCACCTGTTAGACG #17 5′-ACGATGACTGACGGTCATCGTTATATGATGGTACCGCAGCCAG #18 5′ CAACTGTGGTTAAAGCAATAGTGT #19 5′ GCACAGATTCTGAGTAACCATAAT #20 5′pAAGAACTATATTGTCTTTCTCGCATGTCCTATCCTCAGCTGTGATC ATCAGAACTCACCTGTTAGACGCCACCAGCTCCATCCACTCAGTGTGAT TCCACCTTCTCCTCCACCTTCTCC #21 5′-Cy3-ACGATGACTGACGGTCATCGtTCAGAACTCACCTGTTAGACG t = dabsyl-dT #22 5′-CCGTGCTAGAAGGAAxCACGC x = abasic #23 5′-ACGATGACTGACGGTCATCGTCCGTGCTAGAAGGAAxCACGC x = abasic #24 5′-ACGATGACTGACGGTCATCGTCCGTGCTAGAAGGAAACACGC #25 5′ FAM-ACGATGACTGACGGTCATCGtTATATGATGGTACCGCAGCCAG t = dabcyl-dT #26 5′-CCGTGCTAGAAGGAAxCACGC x = 5-nitroindole + linker arm #27 5′-ACGATGACTGACGGTCATCGTCCGTGCTAGAAGGAAxCACGC x = 5-nitroindole + linker
[0075] [0075]
1
27
1
22
DNA
Artificial sequence
Synthetic oligonucleotide
1
cagctgagga taggacattc ga 22
2
21
DNA
Artificial sequence
Synthetic oligonucleotide
2
tcagaactca cctgttagac g 21
3
36
DNA
Artificial sequence
Synthetic oligonucleotide
3
atcagcaccc tggctgatct tagtgtcagg atacgg 36
4
41
DNA
Artificial sequence
Synthetic oligonucleotide
4
atcagcaccc tggctgatta gtacgcttct actccctctt g 41
5
24
DNA
Artificial sequence
Synthetic oligonucleotide
5
actagagctg agacatgacg agtc 24
6
22
DNA
Artificial sequence
Synthetic oligonucleotide
6
acgacgtgtg accagtcaac at 22
7
24
DNA
Artificial sequence
Synthetic oligonucleotide
7
actagagctg agacatgacg agtc 24
8
22
DNA
Artificial sequence
Synthetic oligonucleotide
8
acgacgtgtg accagtcaac at 22
9
24
RNA
Artificial sequence
Synthetic oligonucleotide
9
acuagagcug agacaugacg aguc 24
10
22
RNA
Artificial sequence
Synthetic oligonucleotide
10
acgacgugug accagucaac au 22
11
21
DNA
Artificial sequence
Synthetic oligonucleotide
11
ccgtgctaga aggaaacacg c 21
12
15
DNA
Artificial sequence
Synthetic oligonucleotide
12
gtaccgcagc cagtc 15
13
18
DNA
Artificial sequence
Synthetic oligonucleotide
13
tatatgatgg taccgcag 18
14
21
DNA
Artificial sequence
Synthetic oligonucleotide
14
ccgtgctaga aggaaacacg c 21
15
22
DNA
Artificial sequence
Synthetic oligonucleotide
15
tatatgatgg taccgcagcc ag 22
16
42
DNA
Artificial sequence
Synthetic oligonucleotide
16
acgatgactg acggtcatcg ttcagaactc acctgttaga cg 42
17
43
DNA
Artificial sequence
Synthetic oligonucleotide
17
acgatgactg acggtcatcg ttatatgatg gtaccgcagc cag 43
18
24
DNA
Artificial sequence
Synthetic oligonucleotide
18
caactgtggt taaagcaata gtgt 24
19
24
DNA
Artificial sequence
Synthetic oligonucleotide
19
gcacagattc tgagtaacca taat 24
20
107
DNA
Artificial sequence
Synthetic oligonucleotide
20
aagaactata ttgtctttct cgcatgtcct atcctcagct gtgatcatca gaactcacct 60
gttagacgcc accagctcca tccactcagt gtgattccac cttctcc 107
21
42
DNA
Artificial sequence
Synthetic oligonucleotide
21
acgatgactg acggtcatcg ttcagaactc acctgttaga cg 42
22
21
DNA
Artificial sequence
Synthetic oligonucleotide
22
ccgtgctaga aggaancacg c 21
23
42
DNA
Artificial sequence
Synthetic oligonucleotide
23
acgatgactg acggtcatcg tccgtgctag aaggaancac gc 42
24
42
DNA
Artificial sequence
Synthetic oligonucleotide
24
acgatgactg acggtcatcg tccgtgctag aaggaaacac gc 42
25
43
DNA
Artificial sequence
Synthetic oligonucleotide
25
acgatgactg acggtcatcg ttatatgatg gtaccgcagc cag 43
26
21
DNA
Artificial sequence
Synthetic oligonucleotide
26
ccgtgctaga aggaancacg c 21
27
42
DNA
Artificial sequence
Synthetic oligonucleotide
27
acgatgactg acggtcatcg tccgtgctag aaggaancac gc 42 | The invention discloses methods of reducing background signal in nucleic acid amplification reactions by the use of primers in the case of isothermal amplification which include at least one modification selected from a nucleotide analogue, a hairpin loop at the 5′ end of the primer, a ribonucleotide or a fluor or quencher. For more general nucleic acid amplification reactions the primer includes at least two of the modifications. | 2 |
CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a continuation of prior co-pending U.S. patent application Ser. No. 14/323,076, filed Jul. 3, 2014, which is a continuation of prior U.S. patent application Ser. No. 11/833,073, filed Aug. 2, 2007. One or more portions of these prior U.S. patent applications might be viewed as being related (at least in part) to one or more portions of one or more of following applications: U.S. patent application Ser. No. 11/173,851, filed Jun. 30, 2005; U.S. patent application Ser. No. 11/322,669, filed Dec. 30, 2005; and U.S. patent application Ser. No. 11/395,488, filed on Mar. 30, 2006. Each of the foregoing U.S. patent applications is hereby incorporated herein by reference in its entirety.
BACKGROUND
Software programs are subject to complex and evolving attacks by malware seeking to gain control of computer systems. These attacks can take on a variety of different forms ranging from attempts to crash the software program to subversion of the program for alternate purposes. Additionally, it is particularly difficult to protect the run-time data of the program. The protection of this run-time data is especially important when it involves the program's secrets and configuration information or digital rights protection keying material needed by applications to protect content in main memory and while in transit.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the invention are illustrated by way of example and not by way of limitation in the figures of the accompanying drawings, in which like references indicate similar elements and in which:
FIG. 1 illustrates a platform to provide secure vault service for software components within an execution environment, in accordance with an embodiment of the present invention;
FIG. 2 illustrates a platform utilizing parallel execution environments, in accordance with an embodiment of the present invention;
FIG. 3 illustrates operational phases of secure vault service for software components within an execution environment, in accordance with an embodiment of the present invention;
FIG. 4 illustrates intra-partitioning of portions of a component to provide secure vault service in accordance with an embodiment of the present invention.
FIG. 5 illustrates operational phases of lock service, in accordance with an embodiment of the present invention; and
FIG. 6 illustrates operational phases of unlock service, in accordance with an embodiment of the present invention.
DETAILED DESCRIPTION
Embodiments of the present invention may provide a method, apparatus, and system for secure vault service for software components within an execution environment on a platform. In embodiments, secure vault service helps to protect data in memory during both run-time and while being stored offline from other applications and from other components (such as operating system components or the operating system itself).
Various embodiments may comprise one or more elements. An element may comprise any structure arranged to perform certain operations. Each element may be implemented as hardware, software, or any combination thereof, as desired for a given set of design parameters or performance constraints. Although an embodiment may be described with a limited number of elements in a certain topology by way of example, the embodiment may include more or less elements in alternate topologies as desired for a given implementation. It is worthy to note that any reference to “one embodiment” or “an embodiment” means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment. The appearances of the phrase “in one embodiment” in various places in the specification are not necessarily all referring to the same embodiment.
FIG. 1 illustrates a platform 100 to provide for secure vault service for software components within an execution environment, in accordance with an embodiment of the present invention. The platform 100 may have an execution environment 104 , which may be the domain of an executing operating system (OS) 108 . The OS 108 may be a component configured to execute and control general operation of other components within the execution environment 104 , such as the software component 112 , subject to intra-partition memory access protections provided to selected components by an underlying management module 116 , to be discussed in further detail below.
In some embodiments, the component 112 may be a supervisory-level component, e.g., a kernel component. In various embodiments, a kernel component may be services (e.g., loader, scheduler, memory manager, etc.), extensions/drivers (e.g., for a network card, a universal serial bus (USB) interface, a disk drive, etc.), or a service-driver hybrid (e.g., intrusion detectors to watch execution of code). Alternatively, in embodiments, the component 112 may be an application process, thread, or other user space program, service or library.
As used herein, the term “component” is intended to refer to programming logic and associated data that may be employed to obtain a desired outcome. The term component may be synonymous with “module” or “agent” and may refer to programming logic that may be embodied in hardware or firmware, or in a collection of software instructions, possibly having entry and exit points, written in a programming language, such as, for example, C++, Intel Architecture 32 bit (IA-32) executable code, etc.
A software component may be compiled and linked into an executable program, or installed in a dynamic link library, or may be written in an interpretive language such as BASIC. It will be appreciated that software components may be callable from other components or from themselves, and/or may be invoked in response to detected events or interrupts. Software instructions may be provided in a machine accessible medium, which when accessed, may result in a machine performing operations or executions described in conjunction with components of embodiments of the present invention. Machine accessible medium may be firmware, e.g., an electrically erasable programmable read-only memory (EEPROM), or other recordable/non-recordable medium, e.g., read-only memory (ROM), random access memory (RAM), magnetic disk storage, optical disk storage, etc. It will be further appreciated that hardware components may be comprised of connected logic units, such as gates and flip-flops, and/or may be comprised of programmable units, such as programmable gate arrays or processors. In some embodiments, the components described herein are implemented as software modules, but nonetheless may be represented in hardware or firmware. Furthermore, although only a given number of discrete software/hardware components may be illustrated and/or described, such components may nonetheless be represented by additional components or fewer components without departing from the spirit and scope of embodiments of the invention.
In addition to intra-partitioning selected components of the execution environment 104 , the management module 116 may arbitrate general component access to hardware resources 118 such as one or more processor(s) 120 , network interface controller (NIC) 124 , storage 128 , and/or memory 132 .
The processor(s) 120 may execute programming instructions of components of the platform 100 . The processor(s) 120 may be single and/or multiple-core processor(s), controller(s), application specific integrated circuit(s) (ASIC(s)), etc.
In an embodiment, storage 128 may represent non-volatile storage to store persistent content to be used for the execution of the components on the platform 100 , such as, but not limited to, operating system(s), program files, configuration files, etc. In an embodiment, storage 128 may include stored content 136 , which may represent the persistent store of source content for the component 112 . The persistent store of source content may include, e.g., executable code store that may have executable files and/or code segments, links to other routines (e.g., a call to a dynamic linked library (DLL)), a data segment, etc.
In various embodiments, storage 128 may include integrated and/or peripheral storage devices, such as, but not limited to, disks and associated drives (e.g., magnetic, optical), universal serial bus (USB) storage devices and associated ports, flash memory, ROM, non-volatile semiconductor devices, etc.
In various embodiments, storage 128 may be a storage resource physically part of the platform 100 or it may be accessible by, but not necessarily a part of, the platform 100 . For example, the storage 128 may be accessed by the platform 100 over a network 140 via the network interface controller 124 .
Upon a load request, e.g., from a loading component or agent of the OS 108 , the management module 116 and/or the OS 108 may load the stored content 136 from storage 128 into memory 132 as active content 144 for operation of the component 112 in the execution environment 104 .
In various embodiments, the memory 132 may be volatile storage to provide active content for operation of components on the platform 100 . In various embodiments, the memory 132 may include RAM, dynamic RAM (DRAM), static RAM (SRAM), synchronous DRAM (SDRAM), dual-data rate RAM (DDRRAM), cache, etc.
In some embodiments, the memory 132 may organize content stored therein into a number of groups of memory locations. These organizational groups, which may be fixed and/or variable sized, may facilitate virtual memory management. The groups of memory locations may be pages, segments, or a combination thereof.
A virtual memory utilizing paging may facilitate the emulation of a large logical/linear address space with a smaller physical memory page. Therefore, the execution environment 104 may provide a virtual execution environment in which the components may operate, which may then be mapped into physical pages of the memory 132 . Page tables maintained by the OS 108 and/or management module 116 may map the logical/linear addresses provided by components of the execution environment 104 to physical address of the memory 132 . More details of the implementation of paging, and in particular paging with respect to intra-partitioning of components, may be given below in accordance with embodiments of this invention.
In various embodiments, the component 112 , or portions thereof, may be selected for intra-partitioning to support secure vault services. Here, the management module 116 may identify and partition off portions of the component 112 to control access by the OS 108 or other components to the component 112 . Partitioned portions may include any portion, up to all, of the particular component. A partitioned portion may be sequestered, either physically or virtually, from other components within the same execution environment, such that intra-execution environment accesses may be monitored and restricted, if necessary, by the underlying platform. Intra-partitioning may facilitate insulation of, e.g., component 112 from the OS 108 , without requiring that the component 112 operate in an entirely separate execution environment, with a separate OS. Intra-partitioning may also afford the component 112 a level of protection from other components, even those of similar or higher privilege levels, within the execution environment 104 that may be compromised in some manner, e.g., by malware, rootkits, critical runtime failures, etc. Embodiments of this invention may provide for this protection and secure vault services while still allowing permitted interactions between the component 112 and other components, e.g., the OS 108 , of the execution environment 104 . Controlling access by the OS 108 to the component 112 may include various levels of access restrictions, as will be discussed below in further detail.
In various embodiments, intra-partitioning of components to support secure vault services within an execution environment may be useful in a platform having multiple, execution environments, such as virtual machines operating in a virtualization technology (VT) enabled platform. In such an embodiment, a management module may include, or be a part of, a virtual machine monitor (VMM).
FIG. 2 illustrates a platform 200 utilizing virtualization to provide parallel execution environments in accordance with an embodiment of this invention. In various embodiments, the platform 200 may be similar to, and substantially interchangeable with, the platform 100 . Furthermore, elements described below may be similar to, and substantially interchangeable with, like-named elements described above, and vice versa.
In this embodiment a management module, e.g., virtual machine monitor (VMM) 204 , on the platform 200 may present multiple abstractions and/or views of the platform hardware 208 , e.g., one or more processor(s) 212 , network interface controller (NIC) 216 , storage 220 , and/or memory 224 , to the one or more independently operating execution environments, or “virtual machines (VMs),” e.g., guest VM 228 and auxiliary VM 232 . The auxiliary VM 232 may be configured to execute code independently and securely isolated from the guest VM 228 and may prevent components of the guest VM 228 from performing operations that would alter, modify, read, or otherwise affect the components of the auxiliary VM 232 . While the platform 200 shows two VMs, other embodiments may employ any number of VMs.
The components operating in the guest VM 228 and auxiliary VM 232 may each operate as if they were running on a dedicated computer rather than a virtual machine. That is, components operating in the guest VM 228 and auxiliary VM 232 may each expect to control various events and have complete access to hardware 208 . The VMM 204 may manage VM access to the hardware 208 . The VMM 204 may be implemented in software (e.g., as a stand-alone program and/or a component of a host operating system), hardware, firmware, and/or any combination thereof.
The guest VM 228 may include an OS 236 and component 240 . Upon a designated event, the VMM 204 may identify and partition off portions of the component 240 to control access to the partitioned portions by the OS 236 or other components. One or more of these partitioned portions may be used to represent a secure vault. In various embodiments, a designated event may be when stored content 244 is loaded from storage 220 to memory 224 , as active content 248 or when the component 240 requests secure vault services. However, in various embodiments, other designated events may be additionally/alternatively used.
Intra-partition based protections to provide secure vault service may be provided to component 240 as described in FIG. 3 in accordance with an embodiment of this invention. Operational phases shown in FIG. 3 may be referenced by numerals within parentheses. Referring to FIG. 3 , the component 240 may register with the VMM 204 , and more particularly, with an integrity services module (ISM) 252 of the VMM 204 for protection (block 302 ). At this time, the component 240 may also request for secure vault services. In various embodiments, the registration may take place upon an occurrence of a registration event, e.g., loading of the active content 248 into memory 224 , periodically, and/or in some other event-driven manner. In various embodiments, the registration may be initiated by the component 240 , another component within the VM 228 , e.g., the OS 236 , the VMM 204 , or a component of the VM 232 .
Upon receiving the registration, the ISM 252 may cooperate with an integrity measurement module (IMM) 256 operating in the VM 232 to authenticate and verify the integrity of the component 240 (block 304 ). Authentication and verification of the integrity of the component 240 may help to prevent unauthorized modification and/or malicious termination, and may ensure that only recognized components may be afforded protection as defined by an administrator, user or other policy. The IMM 256 may operate in the VM domain 232 in the context of an OS 260 , or in separate hardware and may, therefore, be largely independent of OS 236 . By running outside of the context of the VM 228 , the IMM 256 may have accurate and dependable memory measurement capabilities that may not be present, or possibly compromised, in the context of the OS 236 .
The IMM 256 may provide the ISM 252 a response to the verification request such as pass, fail, pass w/qualification, fail w/qualification, etc. In various embodiments, qualifications may reflect degrees of integrity verification between pass and fail. The IMM 256 effectively identifies or authenticates the component and its data and assures that it is of the expected, correct form in memory.
In some embodiments, the active content 248 may include an integrity manifest, which may be a collection of information to be used in the verification of the integrity of the component 240 . In various embodiments, the integrity manifest may include one or more integrity check values and/or relocation fix-up locations, covering the stored content 244 , e.g., code store and/or static and/or configuration settings/data. The IMM 256 may access the integrity manifest from the active content 248 and verify that the component 240 corresponds, in total or in part, to the integrity manifest. The IMM 256 may verify the authenticity of the integrity manifest itself verifying a cryptographic signature over the integrity manifest structure to assure it is unaltered from its correct form. A comparison may be done of the images through, e.g., a byte-by-byte analysis or through analysis of cryptographic hashes.
In various embodiments, the IMM 256 may search for the active content 248 directly in the memory 224 , e.g., through a direct memory access (DMA) or direct physical memory access. In various embodiments, the linear address of the component 240 may be provided to the IMM 256 , e.g., through the ISM 252 , and the IMM 256 may perform a virtual-to-physical mapping to identify the physical memory locations of the active content 248 . In an embodiment, the VMM 204 may provide special interfaces to IMM 256 to provide access to active content 248 .
In various embodiments, integrity measurement of the active content 248 may be conducted upon the initial registration, periodically, and/or in some other event-driven manner while the component 240 is executing (e.g., request for lock service or unlock service of the secure vault). Integrity measurement upon initial registration request or secure vault services request may help to determine that the initial state of the active content 248 and/or stored content 244 is as expected based on the state of the content at the time it was manufactured, or loaded last. The periodic or event-driven integrity measurements may help to detect attacks that inappropriately change the protected attributes of the active content 248 and/or stored content 244 .
Further details of integrity measurements of components are described in U.S. patent application Ser. No. 11/173,851, filed Jun. 30, 2005, referred to and incorporated above.
The ISM 252 may receive a response from IMM 256 reflecting verification of integrity and location in memory of the active content 248 (block 306 ). If the verification fails, the ISM 252 denies the request and may trigger an alert (block 308 ). If the verification passes, the ISM 252 may cooperate with a memory manager 264 to intra-partition portions of the component 240 for secure vault services (block 310 ). Here, protection is established around a vault or hidden pages in memory so they may only be accessed by the verified component and/or around the entirety of the component itself.
While FIG. 2 illustrates execution environments being virtual partitions, other embodiments may provide different execution environments through other mechanisms, e.g., using a service processor, protected execution mode (such as System Management Mode SMM or Secure Execution Mode SMX, for example) and/or an embedded microcontroller. In various embodiments, an auxiliary environment may be partitioned from a host environment via a variety of different types of partitions, including a virtualized partition (e.g., a virtual machine in a Virtualization Technology (VT) scheme), as shown above, and/or an entirely separate hardware partition (e.g., utilizing Active Management Technologies (AMT), “Manageability Engine” (ME), Platform Resource Layer (PRL) using sequestered platform resources, System Management Mode (SMM), and/or other comparable or similar technologies). In various embodiments, a VT platform may also be used to implement AMT, ME, and PRL technologies.
FIG. 4 illustrates intra-partitioning of portions of the component 240 to support secure vault services in accordance with an embodiment of this invention. In this embodiment, the OS 236 may create a guest page table (GPT) 404 in an OS domain 408 mapping linear addresses of components executing in the VM 228 to physical addresses, or page frames. Component 240 may be set to occupy the 2 nd through 5 th page table entries (PTEs), which refer to page frames having active content 248 , e.g., PF2-PF5. As is the case in VT platforms, the VMM 204 may monitor and trap register pointer (e.g., CR3) changes. When OS 236 creates GPT 404 and provides a CR3 value 410 pointing to the GPT 404 , the VMM 204 may trap on the CR3 change, create an active page table (APT) 412 (which may be a duplicate or shadow copy of the GPT 404 ) in the VMM domain 416 , and change the CR3 value 410 to value 420 pointing to the APT 412 . In this way, the VMM 204 can coordinate accesses to the memory 224 from a number of VMs, e.g., VM 228 and VM 232 .
In this embodiment, the VMM 204 may also create a protected page table (PPT) 424 . The VMM 204 may copy the page frames having the active content 248 , e.g., PF2-PF5, into the PPT 424 and assign the page table entries (PTEs) that do not refer to those page frames, e.g., 1 st PTE and 6 th PTE, with access characteristics 428 to cause a page fault upon execution. Similarly the APT page mappings for the active content (e.g. 2 nd through the 4 th PTE corresponding to PF2-PF4) will have access characteristics to cause a page fault on execution from the active (or OS's) domain. In various embodiments, the access characteristics 428 may be ‘not present,’ ‘execute disabled,’ and/or read-only. In an embodiment, the access characteristics 428 may be ‘not present’ or a combination of ‘execute disable’ and read-only to prevent unauthorized modifications to the active content 248 from the VM 228 . In various embodiments, the setting of the access characteristics 428 may be done by the VMM 204 , requested by the authenticated/verified component 240 , the IMM 256 , and/or by hardware.
The VMM 204 may assign the PTEs of the APT 412 that refer to page frames having partitioned portions of the component 240 , e.g., 2 nd PTE-4 th PTE, with access characteristics 428 . It may be noted that some page frames, e.g., PF5, may be shared between the partitioned and non-partitioned elements. Therefore, in an embodiment the 5 th PTE may not have access characteristics 428 set in either APT 412 or PPT 424 .
In this embodiment, execution flow between the APT 412 and PPT 424 may be managed as follows. Initially, CR3 may have value 420 pointing to APT 412 representing the execution of the guest operating system. An execution instruction pointer (EIP) may start with the 1 st PTE of the APT 412 and, upon an attempted access of the 2 nd PTE, may cause a page fault due to the access characteristics 428 . The VMM 204 may take control, and change CR3 from value 420 to value 432 , pointing to the PPT 424 . The EIP may resume operation at the 2 nd PTE of the PPT 424 , which may be a partitioned element. The EIP may execute through the 3 rd PTE, the 4 th PTE and the 5 th PTE. When the EIP attempts to access the 6 th PTE, the access characteristics 428 may cause another page fault and the VMM 204 may switch the CR3 back to value 420 , for access to the 6 th PTE from the APT 412 .
In some embodiments, the VMM 204 may monitor the execution flow between the APT 412 and PPT 424 to verify that the points the EIP enters and/or exits the PPT 424 are as expected according to the integrity manifest for the component 240 or other policy. Verification that the EIP jumps into the PPT 424 at valid entry points and/or jumps out of the PPT 424 at valid exit points, could facilitate a determination that the component 240 and/or other components in the VM 228 are operating correctly. If the entry/exit point is not as expected, the VMM 204 may determine that the access attempt to the partitioned component 240 is unauthorized and may raise an exception, which in various embodiments could include rejecting the attempted access, redirecting the access attempt to a different or NULL memory region, reporting the rejected access attempt to the OS 236 (for example, by injecting an invalid instruction exception), triggering an interrupt, notifying a separate VM, sending a network notification, and/or causing a halt of the OS 236 as controlled by the VMM).
In various embodiments, the valid entry and/or exit points may be predetermined, e.g., at the time the component 240 is compiled, and/or may be dynamic. A dynamic entry and/or exit point may be created, e.g., when an interrupt occurs. For example, an interrupt may occur when the EIP is at the 3 rd PTE of the PPT 424 , the VMM 204 may gain control, verify that the interrupt is authentic, and record the EIP value, processor register values, and call stack information for use as a dynamic exit point. The dynamic exit point may then serve as a valid entry point upon reentry to the partitioned elements of the PPT 424 . Note that sensitive data in processor registers and the call stack may be stored as part of the dynamic exit point by the VMM 204 and cleaned/deleted before turning control back to the OS via the interrupt handler. This sensitive data may be restored by the VMM 204 when the corresponding dynamic entry point is executed on returning from the interrupt.
Additionally, in some embodiments an execution state (e.g., a stack state and/or a processor state, e.g., register values) may be recorded at an exit and verified upon reentry. This may provide some assurance that an unauthorized alteration/modification did not occur.
In some embodiments data for an execution state verification may include a copy of the entire state or an integrity check value (ICV) calculation. An ICV may be calculated on, for example, the in parameters of a stack frame by setting the out parameters to default values. Likewise, an ICV may be calculated on the out parameters by setting the in parameters to default values.
If the entry/exit point and/or the execution state verification fail the VMM 204 may issue an exception to the access attempt.
Furthermore, in some embodiments, the VMM 204 may verify that the element calling the partitioned elements (e.g., secure vault or hidden pages), e.g., PF2-PF4, is permitted to access them. For example, the VMM 204 may receive a request from a component to access the partitioned elements. The VMM 204 may identify the component, reference access permissions associated with the partitioned elements, and raise an exception if the access permissions do not permit the identified component to access the partitioned elements.
It may be noted that the page tables shown and described in embodiments of this invention may be simplified for clarity of discussion. In various embodiments of this invention page tables may include multiple levels of indirection and thousands or even millions of entries. Furthermore, in various embodiments entries at different levels may be identified differently than as identified in discussions herein. For example, on an IA-32 platform, the top level may be referred to as a page directory entry (PDE), while the bottom entry may be referred to as a page table entry (PTE). Extended or Nested Page Tables for protection, remapping, and/or segmentation of guest physical memory may also be used. The intra-partitioning discussed herein may be applied to any of these variations/extensions in accordance with embodiments of this invention.
Further embodiments of intra-partitioning of portions of the component 240 are described in U.S. patent application Ser. No. 11/395,488, filed on Mar. 30, 2006, referenced above.
Lock service for the secure vault may be provided to the component 240 as described in FIG. 5 , in accordance with an embodiment of this invention. Operational phases shown in FIG. 5 may be referenced by numerals within parentheses. Referring to FIG. 5 , the component 240 requests lock service by passing a data blob to the VMM 204 to be locked in the vault (or hidden pages) belonging to the PPT of component 240 (block 502 ). Note that in embodiments, the data could be code too. In embodiments, the component 240 may make the request to the VMM 204 via a hypercall. Once locked in the vault, the data blob will be hidden or not accessible by other software in the platform. In embodiments, the secure vault services module 253 ( FIG. 2 ) of the VMM 204 may be incorporated into the VMM 204 to perform the secure vault services described herein.
The integrity of the component 240 is verified (block 504 ), as was described above with reference to block 304 of FIG. 3 . The ISM 252 may receive a response from IMM 256 reflecting verification of integrity of the active content 248 (block 506 ). If the verification fails, the ISM 252 denies the request and may trigger an alert (block 508 ). If the verification passes, the VMM 204 derives a unique key for the vault (block 510 ). In embodiments, the VMM 204 derives the unique key for the vault from its own key or keys via a one-way cryptographic operation. The VMM 204 can obtain its key from the trusted platform module (TPM) as part of the measured secure boot process that loaded the VMM 204 . When the TPM ascertains authenticity and integrity of the loaded VMM 204 , the TPM may release its key to the VMM 204 . Thus, the basis for trust can be extended from a measured VMM 204 directly to applications or components running one, two or more layers removed even in a non-trusted, unmeasured, or even compromised operating system.
The VMM 204 then encrypts the data blob (block 512 ). In embodiments, the VMM 204 encrypts the data blob using its own secret key. The VMM 204 then stores or places the encrypted data blob in the vault (block 514 ).
The VMM 204 computes a cryptographic message authentication code (MAC) of the data blob and of a token (block 516 ). In embodiments, MAC field in the token is set to all zeros. In embodiments, a data structure may be utilized that maps tokens to components or agents. Here, one token is assigned to each component and the data structure represents a mapping between the token and the data blob key for the particular component. The data blob may also identify the owning component based on the integrity manifest identifier. This information too would be in the computation of the MAC.
The VMM 204 places the computed MAC in the token ( 518 ). The VMM 204 then sends the token to the component 240 , including a reference to the manifest for verification when unlocking the vault in the future to gain access to the data blob (block 520 ). The locked content may then be used or stored by the component 240 , where the clear text can be inaccessible and may not be modified by the OS or other components.
Unlock service for the secure vault may be provided to the component 240 as described in FIG. 6 in accordance with an embodiment of this invention. Operational phases shown in FIG. 6 may be referenced by numerals within parentheses. Referring to FIG. 6 , the component 240 requests unlock service for the vault by passing the encrypted data blob and token to the VMM 204 (block 602 ). In embodiments, the component 240 may make the request to the VMM 204 via a hypercall.
The integrity of the component 240 is verified (block 604 ), as was described above with reference to block 304 of FIG. 3 . The ISM 252 may receive a response from IMM 256 reflecting verification of integrity of the active content 248 (block 606 ). If the verification failed, the ISM 252 denies the request and may trigger an alert (block 608 ). If the verification passes, the VMM 204 verifies the integrity of the MAC in the token (block 610 ). Here, the VMM 204 uses its own secret key to prove the token references specified component's manifest (block 612 ). If the verification fails, the ISM 252 denies the request and may trigger an alert (block 608 ). If the verification passes, the VMM 204 matches the secret data blob (block 614 ).
The VMM 204 decrypts the data blob using information in the token and the VMM's secret key (block 616 ). The VMM 204 places the unencrypted data blob in the vault (block 618 ). The component 240 can now access the clear text data in the vault (block 620 ).
In embodiments, a random value or nonce may be part of the encrypted data blob. A nonce is generally not a replay prevention mechanism. Replay protection may be needed if user can back reverse, but may not be required if there is a source of trusted time that can be provided to the component 240 for incorporation in the data blob. Here, in embodiments, the component 240 may be responsible for detecting back reverses and to use the TPM, clock, or remote entity if replay is a concern.
In embodiments, instead of encrypting the data, the token may be used to provide a MAC of the unencrypted data and manifest reference using the VMM 204 secret key to validate the integrity of the information to the component 240 in the future. Here, the same lock and unlock procedure is performed, but the integrity check value is simply calculated on the lock and verified on the unlock operation without encrypting or decrypting the clear text data. In embodiments, for MAC generation, an authenticated encryption mode may be used that both encrypts the data and generates the MAC, or derives a second (authentication key) and applies a function such as a keyed-hashed message authentication code (HMAC) based on SHA256, for example.
Embodiments may also allow content to be locked by one component or set of components yet to be unlocked by another component or set of components. In one embodiment, this is achieved by the locking component identifying to the VMM 204 the destination component that can unlock the data blob via its integrity manifest identifier (or set of identifiers). These identifiers are also integrity protected via the MAC during the lock procedure and verified by the VMM 204 during the unlock procedure to assure that only the targeted destination component(s) may access or modify the content. Such an embodiment may specify both the source and destination integrity manifest identifiers to assure that a protocol may be in place so the destination may determine the component that was source of the locked content was likewise verified by the VMM 204 as the authentic source of the content prior to the data being locked.
Embodiments of the invention may be used for a variety of applications (e.g., security and networking applications) and components (e.g., OS components) to store their secrets at runtime, to make their configuration and secrets secure from attack and to allow these components to reliably attest to the thrust worthiness of the system in the network. In embodiments, applications may utilize the invention to protect keys and configuration information both at runtime and while stored offline so only the properly identified components or agents can access their corresponding secrets. In embodiments, content protection applications can likewise persist their keying material rendering it inaccessible even if the underlying OS is compromised in some fundamental way, and preventing content from being accessed from compromised components. Cryptographic algorithms used for locking and unlocking the data blob may be symmetric, asymmetric or any combination thereof.
Various embodiments may be implemented using hardware elements, software elements, or a combination of both. Examples of hardware elements may include processors, microprocessors, circuits, circuit elements (e.g., transistors, resistors, capacitors, inductors, and so forth), integrated circuits, application specific integrated circuits (ASIC), programmable logic devices (PLD), digital signal processors (DSP), field programmable gate array (FPGA), logic gates, registers, semiconductor device, chips, microchips, chip sets, and so forth. Examples of software may include software components, programs, applications, computer programs, application programs, system programs, machine programs, operating system software, middleware, firmware, software modules, routines, subroutines, functions, methods, procedures, software interfaces, application program interfaces (API), instruction sets, computing code, computer code, code segments, computer code segments, words, values, symbols, or any combination thereof. Determining whether an embodiment is implemented using hardware elements and/or software elements may vary in accordance with any number of factors, such as desired computational rate, power levels, heat tolerances, processing cycle budget, input data rates, output data rates, memory resources, data bus speeds and other design or performance constraints.
Some embodiments may be described using the expression “coupled” and “connected” along with their derivatives. These terms are not intended as synonyms for each other. For example, some embodiments may be described using the terms “connected” and/or “coupled” to indicate that two or more elements are in direct physical or electrical contact with each other. The term “coupled,” however, may also mean that two or more elements are not in direct contact with each other, but yet still co-operate or interact with each other.
Some embodiments may be implemented, for example, using a machine-readable medium or article which may store an instruction or a set of instructions that, if executed by a machine, may cause the machine to perform a method and/or operations in accordance with the embodiments. Such a machine may include, for example, any suitable processing platform, computing platform, computing device, processing device, computing system, processing system, computer, processor, or the like, and may be implemented using any suitable combination of hardware and/or software. The machine-readable medium or article may include, for example, any suitable type of memory unit, memory device, memory article, memory medium, storage device, storage article, storage medium and/or storage unit, for example, memory, removable or non-removable media, erasable or non-erasable media, writeable or rewriteable media, digital or analog media, hard disk, floppy disk, Compact Disk Read Only Memory (CD-ROM), Compact Disk Recordable (CD-R), Compact Disk Rewriteable (CD-RW), optical disk, magnetic media, magneto-optical media, removable memory cards or disks, various types of Digital Versatile Disk (DVD), a tape, a cassette, or the like. The instructions may include any suitable type of code, such as source code, compiled code, interpreted code, executable code, static code, dynamic code, encrypted code, and the like, implemented using any suitable high-level, low-level, object-oriented, visual, compiled and/or interpreted programming language.
Unless specifically stated otherwise, it may be appreciated that terms such as “processing,” “computing,” “calculating,” “determining,” or the like, refer to the action and/or processes of a computer or computing system, or similar electronic computing device, that manipulates and/or transforms data represented as physical quantities (e.g., electronic) within the computing system's registers and/or memories into other data similarly represented as physical quantities within the computing system's memories, registers or other such information storage, transmission or display devices. The embodiments are not limited in this context.
Numerous specific details have been set forth herein to provide a thorough understanding of the embodiments. It will be understood by those skilled in the art, however, that the embodiments may be practiced without these specific details. In other instances, well-known operations, components and circuits have not been described in detail so as not to obscure the embodiments. It can be appreciated that the specific structural and functional details disclosed herein may be representative and do not necessarily limit the scope of the embodiments.
Although the subject matter has been described in language specific to structural features and/or methodological acts, it is to be understood that the subject matter defined in the appended claims is not necessarily limited to the specific features or acts described above. Rather, the specific features and acts described above are disclosed as example forms of implementing the claims. | Embodiments of apparatuses, articles, methods, and systems for secure vault service for software components within an execution environment are generally described herein. An embodiment includes the ability for a Virtual Machine Monitor, Operating System Monitor, or other underlying platform capability to restrict memory regions for access only by specifically authenticated, authorized and verified software components, even when part of an otherwise compromised operating system environment. The underlying platform to lock and unlock secrets on behalf of the authenticated/authorized/verified software component provided in protected memory regions only accessible to the authenticated/authorized/verified software component. Other embodiments may be described and claimed. | 6 |
CLAIM OF PRIORITY UNDER 35 U.S.C. §120
[0001] The present Application for Patent is a Continuation and claims priority to U.S. patent application Ser. No. 09/933,607 entitled “METHOD AND SYSTEM FOR A HANDOFF IN A BROADCAST COMMUNICATION SYSTEM” filed Aug. 20, 2001, now allowed, and assigned to the assignee hereof and hereby expressly incorporated by reference herein.
BACKGROUND
[0002] 1. Field
[0003] The present invention relates to broadcast communications,.otherwise known as point-to-multipoint, in a wireline or a wireless communication system. More particularly, the present invention relates to a system and method for a handoff in such a broadcast communication system.
[0004] 2. Background
[0005] Communication systems have been developed to allow transmission of information signals from an origination station to a physically distinct destination station. In transmitting information signal from the origination station over a communication channel, the information signal is first converted into a form suitable for efficient transmission over the communication channel. Conversion, or modulation, of the information signal involves varying a parameter of a carrier wave in accordance with the information signal in such a way that the spectrum of the resulting modulated carrier is confined within the communication channel bandwidth. At the destination station the original information signal is replicated from the modulated carrier wave received over the communication channel. Such a replication is generally achieved by using an inverse of the modulation process employed by the origination station.
[0006] Modulation also facilitates multiple-access, i.e., simultaneous transmission and/or reception, of several signals over a common communication channel. Multiple-access communication systems often include a plurality of subscriber units requiring intermittent service of relatively short duration rather than continuous access to the common communication channel. Several multiple-access techniques are known in the art, such as time division multiple-access (TDMA), frequency division multiple-access (FDMA), and amplitude modulation multiple-access (AM). Another type of a multiple-access technique is a code division multiple-access (CDMA) spread spectrum system that conforms to the “TIA/EIA/IS-95 Mobile Station-Base Station Compatibility Standard for Dual-Mode Wide-Band Spread Spectrum Cellular System,” hereinafter referred to as the IS-95 standard. The use of CDMA techniques in a multiple-access communication system is disclosed in U.S. Pat. No. 4,901,307, entitled “SPREAD SPECTRUM MULTIPLE-ACCESS COMMUNICATION SYSTEM USING SATELLITE OR TERRESTRIAL REPEATERS,” and U.S. Pat. No. 5,103,459, entitled “SYSTEM AND METHOD FOR GENERATING WAVEFORMS IN A CDMA CELLULAR TELEPHONE SYSTEM,” both assigned to the assignee of the present invention.
[0007] A multiple-access communication system may be a wireless or wire-line and may carry voice and/or data. An example of a communication system carrying both voice and data is a system in accordance with the IS-95 standard, which specifies transmitting voice and data over the communication channel. A method for transmitting data in code channel frames of fixed size is described in detail in U.S. Pat. No. 5,504,773, entitled “METHOD AND APPARATUS FOR THE FORMATTING OF DATA FOR TRANSMISSION,” assigned to the assignee of the present invention. In accordance with the IS-95 standard, the data or voice is partitioned into code channel frames that are 20 milliseconds wide with data rates as high as 14.4 Kbps. Additional examples of a communication systems carrying both voice and data comprise communication systems conforming to the “3rd Generation Partnership Project” (3GPP), embodied in a set of documents including Document Nos. 3G TS 25.211, 3G TS 25.212, 3G TS 25.213, and 3G TS 25.214 (the W-CDMA standard), or “TR-45.5 Physical Layer Standard for cdma2000 Spread Spectrum Systems” (the IS-2000 standard).
[0008] An example of a data only communication system is a high data rate (HDR) communication system that conforms to the TIA/EIA/IS-856 industry standard, hereinafter referred to as the IS-856 standard. This HDR system is based on a communication system disclosed in application Ser. No. 08/963,386, entitled “METHOD AND APPARATUS FOR HIGH RATE PACKET DATA TRANSMISSION,” filed Nov. 3, 1997, now U.S. Pat. No. 6,574,211, issued on Jun. 3, 2003, assigned to the assignee of the present invention. The HDR communication system defines a set of data rates, ranging from 38.4 kbps to 2.4 Mbps, at which an access point (AP) may send data to a subscriber station (access terminal, AT). Because the AP is analogous to a base station, the terminology with respect to cells and sectors is the same as with respect to voice systems.
[0009] In a multiple-access communication system, communications between users are conducted through one or more base stations. A first user on one subscriber station communicates to a second user on a second subscriber station by transmitting data on a reverse link to a base station. The base station receives the data and can route the data to another base station. The data is transmitted on a forward link of the same base station, or the other base station, to the second subscriber station. The forward link refers to transmission from a base station to a subscriber station and the reverse link refers to transmission from a subscriber station to a base station. Likewise, the communication can be conducted between a first user on one subscriber station and a second user on a landline station. A base station receives the data from the user on a reverse link, and routes the data through a public switched telephone network (PSTN) to the second user. In many communication systems, e.g., IS-95, W-CDMA, IS-2000, the forward link and the reverse link are allocated separate frequencies.
[0010] When a subscriber station travels outside the boundary of the base station with which the subscriber station currently communicates, it is desirable to maintain the communication link by transferring the call to a different subscriber station. The method and system for providing a communication with a subscriber station through more than one base station during the soft handoff process are disclosed in U.S. Pat. No. 5,267,261, entitled “MOBILE ASSISTED SOFT HANDOFF IN A CDMA CELLULAR TELEPHONE SYSTEM,” assigned to the assignee of the present invention. The method and system for providing a softer handoff is described in detail in U.S. Pat. No. 5,933,787, entitled “METHOD AND APPARATUS FOR PERFORMING HANDOFF BETWEEN SECTORS OF A COMMON BASE STATION,” assigned to the assignee of the present invention. Using these methods, communication between the subscriber stations is uninterrupted by the eventual handoff from an original base station to a subsequent base station. This type of handoff may be considered a “soft” handoff in that communication with the subsequent base station is established before communication with the original base station is terminated. When the subscriber unit is in communication with two base stations, the subscriber unit combines the signals received from each base station in the same manner that multipath signals from a common base station are combined.
[0011] In accordance with the above-cited inventions, each base station transmits a pilot signal of a common PN spreading code offset in code phase from pilot signals of other base stations. A subscriber station assisted soft handoff operates based on the pilot signal strength detected by the subscriber station. To streamline the process of searching for pilots, four distinct sets of pilot offsets are defined: the Active Set, the Candidate Set, the Neighbor Set, and the Remaining Set. The Active Set identifies the base station(s) or sector(s) through which the subscriber station is communicating. The Candidate Set identifies the base station(s) or sector(s) for which the pilots have been received at the subscriber station with sufficient signal strength to make them members of the Active Set, but have not been placed in the Active Set by the base station(s). The Neighbor Set identifies the base station(s) or sector(s), which are likely candidates for the establishment of communication with the subscriber station. The Remaining Set identifies the base station(s) or sector(s) having all other possible pilot offsets in the current system, excluding those pilot offsets currently in the Active, the Candidate and Neighbor sets.
[0012] The subscriber station is provided with a list of PN offsets corresponding to base stations of neighboring cells. In addition, the subscriber station is provided with a message which identifies at least one pilot corresponding to a base station to which the subscriber station is to communicate through. These lists are stored at the subscriber station as a Neighbor Set and an Active Set of pilots, and are updated as conditions change.
[0013] When communication is initially established, a subscriber unit communicates through a first base station and the Active Set contains only a pilot signal of the first base station. The subscriber unit monitors pilot signal strength of the base stations of the Active Set, the Candidate Set, the Neighbor Set, and the Remaining Set. When a pilot signal of a base station in the Neighbor Set or Remaining Set exceeds a predetermined threshold level (T_ADD), the pilot signal identifier is added to the Candidate Set. The subscriber unit communicates a Power Strength Measurement Message (PSMM) to the first base station identifying the new base station. A system controller decides whether to establish communication between the new base station and the subscriber unit, and communicates the decision in a Handoff Direction Message (HDM). The message identifies the pilots of the Active Set which correspond to base stations through which the subscriber station is to communicate. The system controller also communicates information to each base station corresponding to a new pilot in the Active Set which instructs each of these base stations to establish communications with the subscriber station. The subscriber station communications are thus routed through all base stations identified by pilots in the subscriber station Active Set.
[0014] When the subscriber unit is communicating through multiple base stations, it continues to monitor the signal strength of the base stations of the Active Set, the Candidate Set, the Neighbor Set, and the Remaining Set. Should the signal strength corresponding to a base station of the Active Set drop below a predetermined threshold (T_DROP) for a predetermined period of time (T_TDROP), the subscriber unit generates and transmits a message to report the event. The system controller receives this message through at least one of the base stations with which the subscriber unit is communicating. The system controller may then decide to terminate communications through the base station whose pilot signal strength as measured at the subscriber station is below the T_DROP.
[0015] The system controller upon deciding to terminate communications through a base station generates a new message identifying the pilots of the Active Set to which the subscriber station is to communicate through. In this message, which identifies pilots of the Active Set, the pilot of the base station to which communications with the subscriber station are to be terminated is not identified. The system controller also communicates information to the base station not identified in the Active Set to terminate communications with the subscriber station. The subscriber station, upon receiving the message identifying pilots of the Active Set, discontinues processing signals from the base station whose pilot is no longer in the Active Set. The subscriber station communications are thus routed only through base stations identified by pilots in the subscriber station Active Set. In the case where there were previously more than one pilot identified in the Active Set and now only one, the subscriber station communicates only to the one base station corresponding to the pilot identified in the subscriber station Active Set.
[0016] The above-described wireless communication service is an example of a point-to-point communication service. In contrast, broadcast services provide central station-to-multipoint communication service. The basic model of a broadcast system consists of a broadcast net of users served by one or more central stations, which transmit information with a certain contents, e.g., news, movies, sports events and the like to the users. Each broadcast net user's subscriber station monitors a common broadcast forward link signal. Because the central station fixedly determines the content, the users are generally not communicating back. Examples of common usage of broadcast services communication systems are TV broadcast, radio broadcast, and the like. Such communication systems are generally highly specialized purpose-build communication systems. With the recent, advancements in wireless cellular telephone systems there has been an interest of utilizing the existing infrastructure of the mainly point-to-point cellular telephone systems for broadcast services. (As used herein, the term “cellular” systems encompasses communication system utilizing both cellular and PCS frequencies.)
[0017] Although the described handoff method for subscriber units acting as point-to-point units described above could be applied to broadcast systems, because in a broadcast system, large number of subscribers monitor a common broadcast forward channel, a handoff based on base station-subscriber station signaling message exchange would result in a high signaling load. Furthermore, as described in the above-cited U.S. Pat. Nos. 5,267,261, and 5,933,787, the transmissions received simultaneously by a subscriber station during handoff are synchronized at the transmitting base stations. Because broadcast transmission is intended for many subscriber stations, the base station cannot synchronize transmission for each subscriber station desiring to handoff.
[0018] Based on the foregoing, there is a need in the art for a system and method for handoff in such a broadcast communication system.
SUMMARY
[0019] Embodiments disclosed herein address the above-stated needs by providing a method for autonomous handoff in a broadcast communication system, by receiving at a subscriber station a broadcast channel transmitted through a first sector, measuring at the subscriber station a quality metric of a forward link transmitted by sectors, identifying at the subscriber station at least one sector, different from the first sector, for which said measured quality metric exceeds a first pre-determined threshold; and combining at the subscriber station broadcast channels received from the first sector and said at least one identified sector.
[0020] In another aspect, the above-stated needs are addressed by providing method for a set management in a broadcast communication system, comprising providing to a subscriber station a first list identifying a first set of sectors; measuring at the subscriber station a quality metric of a forward link transmitted by each identified sector; removing from said first list at the subscriber station an identifier of a sector said measured quality metric of which exceeds a first predetermined level; and placing the identifier of the sector into a second list at the subscriber station.
[0021] In another aspect, the above-stated needs are addressed by providing method for method for transitioning a subscriber station from an area covered by a first sector into an area covered by a different sector in a broadcast communication system, comprising determining at the subscriber station a configuration of a broadcast channel transmitted by a second sector; and transitioning from the coverage area covered by the first sector in accordance with said determined configuration of the broadcast channel transmitted by the second sector.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] [0022]FIG. 1 illustrates conceptual block diagram of a High-Speed Broadcast Service communication system;
[0023] [0023]FIG. 2 illustrates concept of soft-handoff groups in a broadcast communication system;
[0024] [0024]FIG. 3 illustrates an embodiment of signaling pertaining to the changes in a pilot's strength and the pilot's membership in the various sets for subscriber assisted handoff;
[0025] [0025]FIG. 4 illustrates an embodiment of signaling pertaining to the changes in a pilot's strength and the pilot's membership in the various sets in autonomous handoff; and
[0026] [0026]FIG. 5 illustrates an alternative mode, in which a pilot may be added to the Active Set for subscriber assisted handoff.
DETAILED DESCRIPTION
[0027] Definitions
[0028] The word “exemplary” is used herein to mean “serving as an example, instance, or illustration.” Any embodiment described herein as “exemplary” is not necessarily to be construed as preferred or advantageous over other embodiments.
[0029] The terms point-to-point communication is used herein to mean a communication between two subscriber stations over a dedicated communication channel.
[0030] The terms group service, point-to-multipoint communication, push-to-talk, or dispatch service are used herein to mean a communication wherein a plurality of subscriber stations are receiving communication from, typically, one subscriber station.
[0031] The term packet is used herein to mean a group of bits, including data (payload) and control elements, arranged into a specific format. The control elements comprise, e.g., a preamble, a quality metric, and others known to one skilled in the art. Quality metric comprises, e.g., a cyclical redundancy check (CRC), a parity bit, and others known to one skilled in the art.
[0032] The term access network is used herein to mean a collection of base stations (BS) and one or more base stations' controllers. The access network transports data packets between multiple subscriber stations. The access network may be further connected to additional networks outside the access network, such as a corporate intranet or the Internet, and may transport data packets between each access terminal and such outside networks.
[0033] The term base station is used herein to mean the hardware with which subscriber stations communicate. Cell refers to the hardware or a geographic coverage area, depending on the context in which the term is used. A sector is a partition of a cell. Because a sector has the attributes of a cell, the teachings described in terms of cells are readily extended to sectors.
[0034] The term subscriber station is used herein to mean the hardware with which an access network communicates. A subscriber station may be mobile or stationary. A subscriber station may be any data device that communicates through a wireless channel or through a wired channel, for example using fiber optic or coaxial cables. A subscriber station may further be any of a number of types of devices including but not limited to PC card, compact flash, external or internal modem, or wireless or wireline phone. A subscriber station that is in the process of establishing an active traffic channel connection with a base station is said to be in a connection setup state. A subscriber station that has established an active traffic channel connection with a base station is called an active subscriber station, and is said to be in a traffic state.
[0035] The term physical channel is used herein to mean a communication route over which a signal propagates described in terms of modulation characteristics and coding.
[0036] The term logical channel is used herein to mean a communication route within the protocol layers of either the base station or the subscriber station.
[0037] The term communication channel/link is used herein to mean a physical channel or a logical channel in accordance with the context.
[0038] The term reverse channel/link is used herein to mean a communication channel/link through which the subscriber station sends signals to the base station.
[0039] A forward channel/link is used herein to mean a communication channel/link through which a base station sends signals to an subscriber station.
[0040] The term soft handoff is used herein to mean a communication between a subscriber station and two or more sectors, wherein each sector belongs to a different cell. The reverse link communication is received by both sectors, and the forward link communication is simultaneously carried on the two or more sectors' forward links.
[0041] The term softer handoff is used herein to mean a communication between a subscriber station and two or more sectors, wherein each sector belongs to the same cell. The reverse link communication is received by both sectors, and the forward link communication is simultaneously carried on one of the two or more sectors' forward links.
[0042] The term erasure is used herein to mean failure to recognize a message.
[0043] The term dedicated channel is used herein to mean a channel modulated by information specific to an individual subscriber station.
[0044] The term common channel is used herein to mean a channel modulated by information shared among all subscriber stations.
[0045] Description
[0046] As discussed a basic model of a broadcast system comprises a broadcast net of users, served by one or more central stations, which transmit information with a certain contents, e.g., news, movies, sports events and the like to the users. Each broadcast net user's subscriber station monitors a common broadcast forward link signal. FIG. 1 illustrates conceptual block diagram of a communication system 100 , capable of performing High-Speed Broadcast Service (HSBS) in accordance with embodiments of the present invention.
[0047] The broadcast content originates at a content server (CS) 102 . The content server may be located within the carrier network (not shown) or outside Internet (IP) 104 . The content is delivered in a form of packets to a broadcast packet data-serving node (BPDSN) 106 . The term BPSDN is used because although the BPDSN may be physically co-located or be identical to the regular PDSN (not shown), the BPSDN may be logically different from a regular PDSN. The BPDSN 106 delivers the packets according to the packet's destination to a packet control function (PCF) 108 . The PCF is a control entity controlling function of base stations 110 for the HSBS and any general packet data services, as a base station controller is for regular voice services. To illustrate the connection of the high level concept of the HSBS with the physical access network, FIG. 1 shows that the PCF is physically co-located or even identical, but logically different from a base station controller (BSC). One of ordinary skills in the art understands that this is for a pedagogical purposes only. The BSC/PCF 108 provides the packets to base stations 110 . The communication system 100 enables the HSBS by introducing a forward broadcast shared channel 112 (F-BSCH) transmitted by base stations 110 . The F-BSCH 112 need not be transmitted from every base station 110 . A F-SBCH is capable of high data rates that can be received by a large number of subscriber stations. The term forward broadcast shared channel is used.
[0048] The F-BSCH may be monitored by a large number of subscribers 114 . Consequently, the base station-subscriber station signaling message based handoff is not efficient in a HSBS because such a handoff results in a high signaling load and may not be feasible since it is a fixed broadcast transmission not tailored for a particular subscriber station. On the other hand, because of the high power demand for transmission of the common broadcast forward channel, there are only few common broadcast forward channel on a given CDMA carrier, which makes autonomous soft and softer handoff without the base station-subscriber station signaling message exchange practical.
[0049] Therefore, instead of exchanging messages between a base station and a subscriber station desiring to handoff, the information regarding broadcast transmission in neighbor base stations is announced by overhead messages on each channel F-BSCH in each base station. Because a subscriber may soft combine the only synchronous transmissions, a Broadcast Service Parameters Message transmitted in each base station will list the identities of base stations that are part of this sector's soft handoff (SHO) group for each supported F-BSCH. The method and system for signaling, including both mentioned embodiments is described in detail in U.S. patent application Ser. No. 09/933,914, entitled “METHOD AND APPARATUS FOR BROADCAST SIGNALING IN A WIRELESS COMMUNICATION SYSTEM,” filed Aug. 20, 2001, assigned to the assignee of the present invention. As used herein a SHO group means a group of all base station transmitting the Common Broadcast Forward Link synchronously. FIG. 2 illustrates two SHO groups, SHO Group 1 202 comprising BS 1 , BS 2 , and BS 3 , and SHO Group 2 202 comprising BS 4 , BS 5 , BS 6 , and BS 7 .
[0050] Referring to FIG. 2, if a subscriber station crosses boundaries from a coverage area of SHO Group 1 202 to a coverage area of SHO Group 2 202 , a hard handoff is required. The term hard handoff as used here means that monitoring of a first channel is discontinued before monitoring of the second channel begins (“break before make”). On the other hand, if a subscriber station monitors transmissions from a BS 7 and enters a coverage area of a new base station, e.g., BS 6 , because both base stations are in the same SHO group the subscriber can monitor the F-BSCH transmission from the base stations before stop listening to the F-BSCH transmission from the BS 7 .
[0051] Autonomous Soft Handoff
[0052] In one embodiment of the current invention, a subscriber station uses a quality metric of a forward link for decision, which F-BSCH to monitor. The quality metric may comprise, e.g., pilot signal strength, bit-error-rate, packet-error-rate, and other quality metrics known to one of ordinary skills in the art. To streamline the decision process, several distinct sets of pilot offsets and rules from transitioning among the sets are defined as discussed in detail below. For the ease of explanation of essential concepts of the various embodiments, the following discussion uses all sets, i.e., Active Set, the Candidate Set, and the Neighbor Set, and the Remaining Set. When the subscriber stations subscribed to HSBS services acquires a sector, it decodes a message, which provides the subscriber station with a list of identities of sectors that are part of the sector's SHO group for each supported F-BSCH. In accordance with one embodiment, the list is provided in a Broadcast Service Parameters Message transmitted in each sector. In accordance with another embodiment, the list is provided in existing overhead messages. The subscriber station initially assigns identifiers of sectors in the provided list into a Neighbor Set. The subscriber station monitors the signal strength of the sectors in the Neighbor Set, and assigns identifiers of the pilot signal into the Active Set, the Candidate Set, the Neighbor Set, in accordance with the monitored signal strength. As the subscriber station moves around, the subscriber station may update the overhead parameters of the BS 6 simultaneously. The Broadcast Service Parameters Message from the new sector may indicate additional members and delete some members of the SHO groups relative to the information in the old sector Broadcast Service Parameters Message. Therefore, while the Broadcast Service Parameters Message from the BS 6 (BSPM 6 ) contained members {BS 4 , BS 5 , BS 7 }, the Broadcast Service Parameters Message from the BS 7 (BSPM 7 ) contains only members {BS 4 , BS 6 }. The subscriber station thus places certain sectors to a Remaining Set.
[0053] The advantage of a soft handoff is that a subscriber station may combine synchronous transmission of multiple sectors, subject to subscriber station capabilities, e.g., number of receiver fingers, processing power, and other known to one of ordinary skills in the art. Consequently, when the subscriber station decides to monitor an HSBS channel modulating a F-BSCH, assuming that the Active Set contains more than one pilot signal identifiers, the subscriber station may select to combine the F-BSCH from the sectors, the pilot signal identifiers of which belong to the Active Set, and have the highest signal strength. The subscriber station then tunes to the frequency transmitted by the sectors, modulated by the selected F-BSCH that is modulated by the HSBS channel. The subscriber station continues monitoring pilot signal strength of the sectors in the Active Set, the Candidate Set, the Neighbor Set, and the Remaining Set. When a pilot signal of a second sector in the Neighbor Set or Remaining Set qualifies for transition to the Active Set, the subscriber station adds the pilot signal's identifier to the Active Set. Thus, the subscriber station monitors the F-BSCH transmitted by only the sectors identified by pilots in the subscriber station Active Set.
[0054] While the subscriber station is monitoring the F-BSCH transmitted by multiple sectors, the subscriber station continues to measure the signal strength of the sectors of the Active Set, the Candidate Set, the Neighbor Set, and the Remaining Set. Should the signal strength of a pilot signal corresponding to a sector of the Active Set disqualify the pilot signal from being a member of the Active Set, the subscriber station may decide to remove the pilot signal identifier from the Active Set. If the subscriber station monitors the F-BSCH transmitted through the sector, the subscriber station then terminates monitoring the F-BSCH transmitted. In the case where there were previously more than one pilot identified in the Active Set and now only one, the subscriber station monitors only the one sector corresponding to the pilot signal, and identifier of which belongs to the Active Set.
[0055] Pilot Set Management
[0056] As discussed above, as the subscriber station assisted soft and softer handoff as described in the above-referenced U.S. Pat. Nos. 5,267,261, and 5,933,787, the autonomous soft handoff of the present invention utilizes a concept of pilot sets. In accordance with the above-referenced U.S. Pat. Nos. 5,267,261, and 5,933,787, the sector-subscriber station signaling assisted with pilot Set management. However, the autonomous soft handoff in accordance with embodiments of the invention does not utilize such a signaling, therefore, a different method of set management is needed. To better understand concepts of set management, the set management in accordance with the above-referenced U.S. Pat. Nos. 5,267,261, and 5,933,787 is reviewed, and then embodiments in accordance with the present invention are described.
[0057] [0057]FIG. 3 illustrates an embodiment of the signaling pertaining to the changes in a pilot's strength and the pilot's membership in the various sets during a subscriber assisted handoff. In FIG. 3, before time t 0 , the pilot P A is in the Neighbor Set with a rising signal strength as measured by the subscriber station's searcher receiver. However, the pilot signal strength is below the threshold T_ADD, which would qualify the pilot to enter the Candidate Set. The subscriber station control processor makes a decision to place a non-Active or non-Candidate Set member in the Candidate Set when the measured pilot exceeds the threshold value T_ADD, an event to which the subscriber station control processor generates and transmits a PSMM.
[0058] At time t 0 the pilot P A signal strength as measured by the searcher receiver exceeds the value T_ADD. The subscriber station control processor compares the measured value with the T_ADD value and determines that the T_ADD value has been exceeded. The subscriber station control processor thus generates and transmits a corresponding PSMM.
[0059] It should be noted that the searcher may detect several multipath versions of pilot P A , which may be time-shifted from one another by several chips. The sum of all detected usable multipath versions of the pilot may be used for identifying the strength of the pilot.
[0060] The decision for placing a Candidate Set member into the Active Set is made by the system controller. For example, when the measured Candidate pilot is of a signal strength which exceeds the signal strength of one other Active Set member pilot by a predetermined value it may join the Active Set. However there may be limits placed on the number of Active Set members. Should the addition of a pilot to the Active Set exceed the Active Set limit, the weakest Active Set pilot may be removed to another set.
[0061] Once a decision is made by the system controller that a pilot should enter the Active Set, a Handoff Direction Message is sent to the subscriber station, all sectors that have a traffic channel assigned to the subscriber station, which includes the pilot P A in the Active Set. In FIG. 3 at time t 1 the Handoff Direction Message is received at the subscriber station where the identified pilots, including pilot P A , are used to demodulate received signals from the sector from which pilot P A was transmitted and/or from another sector. Once a pilot is identified in the Handoff Direction Message, one version or multipath versions of the information signals if present corresponding to the identified pilot from the same sector may be demodulated. The signals ultimately demodulated may therefore be transmitted from one or more sector and may be multipath versions thereof. During the soft handoff the subscriber station diversity combines at the received signals at the symbol level. Therefore, all sectors participating in the soft handoff must transmit identical symbols, except for closed loop power control subchannel data as discussed later herein.
[0062] In FIG. 3 between the times t 1 and t 2 the pilot P A falls in signal strength to where at time t 2 the signal strength drops below a predetermined threshold value T_DROP. When the signal strength of a pilot drops the value T_DROP for a predetermined period of time, the subscriber station control processor again generates and transmits, at time t 3 , a PSMM.
[0063] In response to this PSMM, the system controller generates a Handoff Direction Message that is sent to the subscriber station, by all sectors having a traffic channel assigned to the subscriber station, which no longer includes the pilot P A in the Active Set. At time t 4 the Handoff Direction Message is received at the subscriber station for removing the pilot P A from the Active Set, for example to the Neighbor Set. Once removed from the Active Set this pilot is no longer used for signal demodulation.
[0064] As well known to one of ordinary skills in the art, a spread spectrum communication system is interference limited. In subscriber station assisted handoff, the Candidate Set serves the purpose of keeping the pilot signal identifier in a convenient place for quick access, and the search frequency for the pilot signals in the Candidate Set is higher than the search frequency for the pilot signals in the Neighbor Set. Therefore, the effect of a delay between the PSMM and the HDM was minimized because upon receiving the HDM, the subscriber could quickly place the pilot signal into Active Set and start traffic channel combining, which improved signal-to-interference-and-noise-ratio (SINR). However, in autonomous handoff, the subscriber can change the search frequency and start traffic channel combining without the delay. Consequently, in one embodiment of the present invention, the Candidate Set is eliminated from the four distinct sets of pilot offsets. Thus, if a pilot strength exceeds a first threshold T_ADD 1 at time t 0 , the pilot is promoted from the Neighbor Set directly to the Active Set. One of ordinary skills in the art recognizes methods of promoting a pilot from a Neighbor Set are equally applicable for promoting a member form the Remaining set.
[0065] In accordance with another embodiment of the present invention, the Candidate Set is retained. Referring to FIG. 4, the transition from a Neighbor Set to a Candidate Set occurs at time t 0 , when a pilot strength exceeds a first threshold T_ADD 1 . The pilot signal is then observed, and in accordance with one embodiment promoted from the Candidate Set to the Active Set when the pilot strength exceeds a second threshold T_ADD 2 at time [[t 1 ]] t 2 . In accordance with another embodiment, a timer for the pilot is started at time t 0 . If the pilot remains in the Candidate Set for the timer interval (T_TADD), the pilot is promoted to the Active Set. If the pilot is removed from the Candidate Set before the T_TADD, the timer is stopped. Thus, the pilot signal is promoted only if the pilot signal strength increases or is stable.
[0066] An alternative mode, in which a pilot may be added to the Active Set, is illustrated in reference to FIG. 5. Referring to FIG. 5, the strength of a pilot signal rises above members of the Active Set. When the signal strength of a pilot signal exceeds pilot signal strength of a pilot of an Active Set by at least T_COMP dB, the subscriber reports that event to the sector. In FIG. 5, pilots P 1 , P 2 and P 3 are members of the Active Set while pilot P 3 is initially a member of another set such as the Neighbor Set.
[0067] Generally the number of Active Set members correspond to the number of data receivers available, however the Active Set may be of a greater number of pilots. The subscriber station is therefore permitted to select from the Active Set member pilots those of greatest signal strength for demodulation of the corresponding data signals. One of ordinary skills in the art understands that one or more pilots of the Active sets may have multipath propagations of the same sector or sector transmitted pilot as received at the subscriber station. In the case of multipath propagations, the subscriber station again selects signals for demodulation corresponding to those multipath versions of the pilots identified in the Active Set pilots of greatest signal strength. Therefore the actual sector signals demodulated by the subscriber station may be from different sectors or from a same sector.
[0068] At time t 0 the pilot P 0 as measured by the searcher receiver and compared with the value T_ADD by the subscriber station control processor is determined to be greater than the value T_ADD. As discussed above, this event results in the subscriber station control processor generating a PSMM, which is transmitted by the subscriber station to a sector for relay to the system control processor. The subscriber station also adds the pilot P 0 to the Candidate Set.
[0069] At time t 1 the pilot P 0 exceeds pilot P 1 by a value greater than the value T_COMP. The subscriber station control processor generates another PSMM, which is transmitted by the subscriber station to a sector for relay to the system control processor. It should be noted that only pilots that are already members of the Candidate Set are compared to Active Set members using the T_COMP criteria. Since the pilot P 0 has exceed the pilot P 1 by the value T_COMP, the system controller may begin setting up a modem at another sector or sector for communicating with the subscriber station. However if the pilot is not of another sector or sector, no setup is necessary. In either case the system controller would then communicate a Handoff Direction Message to the subscriber station including the pilot if not already an Active Set member.
[0070] The procedure is similar as pilot P 0 grows stronger. At time t 2 the pilot P 0 has grown stronger than the next strongest pilot P 2 by a value greater than the value T_COMP. Consequently, the subscriber station control processor generates another PSMM, which is transmitted by the subscriber station to a sector for relay to the system control processor. Since the pilot P 0 has exceed the pilot P 2 by the value T_COMP, the system controller may add the pilot to the Active Set as discussed above if not yet already done.
[0071] In subscriber assisted handoff, the addition of strong pilot to the Active Set via the T_COMP method served the purpose to quickly add a pilot with a fact increasing signal strength to the Active Set. As discussed, a base station controller had discretion to promote a pilot from a Candidate Set to the Active Set. If the sector decided not to promote the pilot to the Active Set, and the pilot signal strength kept rising, the sector transmitting the pilot signal became an interferer. To prompt the base station controller to act, the new PSMM in accordance with the T_COMP method was generated. However, in autonomous handoff, when the subscriber station identifies a pilot with a fast increasing signal strength, the subscriber station can change the search frequency and start channel combining immediately. Consequently, in accordance with one embodiment of the present invention, the T_COMP method of adding pilot identifiers to an Active Set is not utilized.
[0072] The size of the Active Set is limited. Therefore, a subscriber station may refuse to add an identifier of a pilot signal with sufficient signal strength into an Active Set when the Active Set is already full. If the pilot signal strength keeps rising, a sector transmitting the pilot signal became an interferer, and it may be advantageous to remove an identifier of a weaker pilot signal from the Active Set, add the identifier of the fast raising pilot, and start combining a signal from the sector. Therefore, in accordance with another embodiment of the present invention, the alternative mode of adding a pilot to the Active Set is retained. The method must be modified in accordance with the above-described embodiments of the present invention.
[0073] Consequently, in accordance with the embodiment, in which the Candidate Set is eliminated, the subscriber station monitors whether a signal strength of a pilot, an identifier of which is not a member of an Active Set, exceeds a pilot strength of a pilot an identifier of which is a member of the Active Set by a value of T_COMP a . Upon identifying such a pilot, the subscriber station makes a decision whether to add an identifier of the pilot to the Active Set.
[0074] In accordance with the embodiment, in which the Candidate Set is retained, if the transition method to a Candidate Set utilizes the two thresholds T_ADD 1 , and T_ADD 2 , the identifier of a pilot will be added to the Candidate Set when the pilot signal strength exceeds T_ADD 2 as dicussed. The subscriber station monitors whether a signal strength of a pilot, an identifier of which is a member of a Candidate Set, exceeds a pilot strength of a pilot an identifier of which is a member of the Active Set by a value of T_COMP a . Upon identifying such a pilot, the subscriber station makes a decision whether to add an identifier of the pilot to the Active-Set.
[0075] If the transition method to a Candidate Set utilizes the threshold T_ADD 1 , and an expiration of timer interval T_TADD, the subscriber station may decide to add the pilot to the Active Set, once the pilot signal strength exceeds the signal strength of a pilot with the weakest signal strength already in an Active set by the value of T_COMP, regardless of whether the timer interval T_TADD expired or not.
[0076] The pilot is removed from the Active Set whenever the signal strength of the pilot is determined to be below T_DROP a a period exceeding T_DROP a .
[0077] Broadcast Service Handoff Control & Signaling
[0078] Because of the potential mobility of subscriber stations or changing conditions of the F-BSCH, the subscriber station may need to handoff form a coverage area of a original sector to a coverage area of a second sector. The method of performing the handoff depends on a state of the subscriber station in the coverage area of the original sector and the configuration of the original and the second sectors.
[0079] Upon a power-up, a subscriber station enters a system determination substate, in which the system upon which to perform an acquisition attempt is selected. In one embodiment, after having selected a system for system determination, the subscriber station transitions into a pilot acquisition sub-state, in which the subscriber station attempts to demodulate a pilot signal based on the acquisition parameters retrieved in the system determination sub-state. The subscriber station attempts to acquire a CDMA pilot signal in accordance with the acquisition parameters. When the subscriber station detects a pilot signal with energy above a predetermined threshold value, the subscriber station transitions into a Sync channel acquisition sub-state and attempts acquisition of the Sync channel. Typically, the Sync channel as broadcasted by the sectors includes basic system information such as the system identification (SID) and the network identification (NID), but most importantly provides timing information to the subscriber station. The subscriber station adjusts the subscriber's station timing in accordance with the Sync channel information and then enters the subscriber station idle state. The subscriber station begins the idle state processing by receiving a channel provided by the system for overhead messages identified in the Sync channel message, and if a sector, which the subscriber station acquired supports multiple frequencies, both the subscriber station and the sector use a hash function to determine, which frequency to use for communication. The subscriber and sector then use the hash function to determine a paging channel, which the subscriber monitors. In one embodiment, the hashing function accepts number of entities to hash, e.g., frequencies, paging channels, and the like and an international subscriber station identifier (IMSI) and outputs one entity.
[0080] In the idle state the subscriber station can receive messages, receive an incoming call, initiate a call, initiate registration, or initiate message transmission. Furthermore, a subscriber subscribed to an HSBS service may monitor an HSBS channel modulating a F-BSCH. The frequency determined by the hash function may or may not be modulated by F-BSCH. Consequently, if a subscriber station desires to monitor an HSBS channel modulating a F-BSCH on a frequency different form the frequency determined by the hash function, it must re-tune to the frequency modulated by the F-BSCH.
[0081] Based on the foregoing the subscriber station may be in the following states at the original sector:
[0082] State 1: not monitoring F-BSCH, and tuned to the frequency determined by the hash function;
[0083] State 2: not monitoring F-BSCH, and tuned to the frequency modulated by the F-BSCH different form the frequency determined by the hash function; and
[0084] State 3: monitoring F-BSCH and, therefore, tuned to in the frequency modulated by the F-BSCH.
[0085] In accordance with one embodiment, the subscriber station determines the configuration of the second sector in accordance with a value of an HSBS neighbor configuration indicator (NGHBR_CONFIG_HSBS) transmitted by the current sector. Specific values of NGHBR_CONFIG_HSBS indicate, e.g., whether a HSBS configuration of the neighbor sector is known, whether the neighbor sector is transmitting the F-BSCH, whether the F-BSCH of the neighbor sector is being transmitted on the same frequency, whether the HSBS channels are synchronized, whether the same set of HSBS channels are being multiplexed in the same manner into the F-BSCH being transmitted in the neighbor sector, whether autonomous soft-handoff is allowed, and other configuration information known to one skilled in the art. In accordance with one embodiment, the NGHBR_CONFIG_HSBS is included in the Broadcast Service Parameters Message transmitted in the current sector.
[0086] When the subscriber station makes a decision to handoff to a second sector, the subscriber station ascertains the NGHBR_CONFIG_HSBS for the second sector. The subscriber station then takes action in accordance with the value of the NGHBR_CONFIG_HSBS. Several scenarios in accordance with above-listed examples of NGHBR_CONFIG_HSBS values are discussed. One of ordinary skills in the art recognizes that the scenarios discussed are communication system implementation dependent.
[0087] When the subscriber station is in state 1 or 2, the subscriber station is not concerned with the status of the F-BSCH. Consequently, the subscriber station receives a NGHBR_CONFIG_HSBS, and determines configuration parameters for the second sector. The subscriber station then performs idle handoff in accordance with an idle handoff method implemented in the communication system. In one embodiment, the idle handoff method uses the above-disclosed hashing methods to determine a frequency, the subscriber station tunes to and a paging channel the subscriber station starts monitoring. Alternatively, the subscriber station may choose to tune to the frequency modulated by the F-BSCH, even if the subscriber station is not interested in monitoring a HSBS channel at present, if sufficient information about the neighbor HSBS channels is available in the Broadcast Service Parameter Message of the current sector.
[0088] The NGHBR_CONFIG_HSBS received by the subscriber station in state 1 or 2 may indicate that configuration of the second subscriber station is unknown. In one embodiment, the subscriber station handoffs to a sector, for which NGHBR_CONFIG_HSBS indicates that a configuration is known. Alternatively, the subscriber station attempts to find non-broadcast related neighbor information. For example, communication systems in accordance with IS-95 and IS-2000 standards provide a neighbor configuration identifier (NGHBR_CONFIG), which indicates neighbor information, e.g., number of frequency assignment and paging channels. One of ordinary skills in the art recognizes that other communication systems may provide similar information. Consequently, the subscriber station need not initiate the full initialization process as described above, but acquires a frequency and a paging channel of the neighbor sector using the above-described hashing method in accordance with the neighbor information. If such information is not found or is inconclusive, the subscriber station must enter initialization process.
[0089] When a subscriber station in state 3 receives a NGHBR_CONFIG_HSBS indicating that a soft-handoff with the F-BSCH of the second sector is allowed, the subscriber station performs autonomous soft handoff if the subscriber station supports it. A soft handoff is allowed if both sectors belong to the same SHO group, the F-BSCH is being transmitted on the same frequency through both sectors, the same set of HSBS channels are being multiplexed identically onto the F-BSCH, and F-BSCH transmissions are synchronized. Alternatively, the subscriber station performs hard handoff in accordance with the described embodiments, acquires a new sector, and resumes monitoring the HSBS channel.
[0090] When a subscriber station in state 3 receives a NGHBR_CONFIG_HSBS indicating that the HSBS channel is available in the second sector but the transmissions are not synchronized among the sector, the subscriber station performs hard handoff. Because the two broadcast channels are identical, the subscriber station transitions directly to the HSBS channel frequency of the second sector and resumes monitoring HSBS channel. If the subscriber station failed to acquire all necessary parameters from the NGHBR_CONFIG_HSBS, the subscriber station performs a hard handoff, to the second sector, acquires a frequency and a paging channel of the second sector using the above-described hashing method in accordance with the neighbor information, determines information about the HSBS channel from the Broadcast Service Parameters Message, tunes to the HSBS channel frequency, and resumes receiving the HSBS channel.
[0091] The subscriber station in state 3 receives a NGHBR_CONFIG_HSBS indicating that the HSBS channel is available in the second sector, but the configuration parameters of the F-BSCH are different, e.g., the F-BSCH of the second sector is being transmitted on different frequency, set of HSBS channels multiplexed onto the F-BSCH channel is not identical or is not multiplexed in the same manner. The subscriber station performs a hard handoff to the second sector, acquires a frequency and a paging channel of the second sector using the above-described hashing method in accordance with the neighbor information, determines information about the HSBS channel from the Broadcast Service Parameters Message, tunes to the HSBS channel frequency, and resumes receiving the HSBS channel. Alternatively, if the subscriber station can determine the difference, which can be remedied by an action of the subscriber station, e.g., all parameters are identical, except the frequency, the subscriber station may transition directly to the HSBS channel frequency of the second sector and resume monitoring HSBS channel.
[0092] When a subscriber station in state 3 receives a NGHBR_CONFIG_HSBS indicating that the second sector is not transmitting a F-BSCH, in one embodiment, the subscriber station handoff to a sector transmitting a F-BSCH with a weaker, but acceptable, pilot signal. Alternatively, the subscriber station discontinues reception of the F-BSCH and performs idle handoff to the second sector in accordance with an idle handoff method implemented in the communication system. In one embodiment, the idle handoff method uses the above-disclosed hashing methods to determine a frequency the subscriber station tunes to and a paging channel the subscriber station starts monitoring.
[0093] Subscriber station is in state 3, NGHBR_CONFIG_HSBS indicates that configuration of the second sector is unknown. In one embodiment, the subscriber station handoffs to a sector, for which NGHBR_CONFIG_HSBS indicates that a configuration is known, regardless of whether a F-BSCH is transmitted or not. Alternatively, the subscriber station attempts to find non-broadcast related neighbor information. For example, communication system in accordance with IS-95 and IS-2000 standards provide a NGHBR_CONFIG, which indicates neighbor information, e.g., number of frequency assignment and paging channels. One of ordinary skills in the art recognizes that other communication systems may provide similar information. Consequently, the subscriber station need not initiate the full initialization process as described above, but acquires a frequency and a paging channel of the neighbor sector using the above-described hashing method in accordance with the neighbor information. If such information is not found or is inconclusive, e.g., unknown neighbors' configuration, the subscriber station must enter initialization process. Once the subscriber station acquires a new sector, the subscriber station can receive the Broadcast Service Parameter Message to determine availability of HSBS channels in that sector and tune to the appropriate frequency carrying the HSBS channel and resume receiving the HSBS channel.
[0094] Traffic Channel Handoff
[0095] Unlike the above-described embodiments, this embodiment contemplates a handoff for a subscriber station in the dedicated mode (e.g., in a voice call) on a traffic channel, while also monitoring a F-BSCH. In accordance with one embodiment of the present invention, the base station-subscriber station signaling assisted handoff is performed for the call. Furthermore, the handoff methods disclosed in the embodiments of the present invention are performed for the F-BSCH. The base station provides the subscriber station with a new pilot sets for the handoff on a traffic channel via a handoff direction messages. As discussed, the subscriber receives information about the pilot Sets via the Broadcast Service Parameter Message in accordance to one embodiment. However, the subscriber station is able to receives the Broadcast Service Parameter Message only in an idle state.
[0096] Consequently, in accordance with one embodiment, the handoff direction message indicates the pilot sets for both the traffic channel and the F-BSCH. As discussed, SHO groups determine the Active Set for a F-BSCH.
[0097] In accordance with another embodiment, no information pertaining to the FBSCH is sent in the handoff direction message because the F-BSCH is not a dedicated channel. Rather, the F-BSCH SHO groups for each sector are sent via dedicated mode counterparts to overhead messages.
[0098] Note that whether the F-BSCH is soft-combined or not depends on the SHO groups involved (as advertised by the Broadcast Service Parameters Message) and is not related to whether the dedicated traffic channel is being soft-combined or not.
[0099] One skilled in the art will appreciate that although the flowchart diagrams are drawn in sequential order for comprehension, certain steps can be carried out in parallel in an actual implementation. Furthermore, unless indicate otherwise, method steps can me interchanged without departing form the scope of the invention.
[0100] Those of skill in the art would understand that information and signals may be represented using any of a variety of different technologies and techniques. For example, data, instructions, commands, information, signals, bits, symbols, and chips that may be referenced throughout the above description may be represented by voltages, currents, electromagnetic waves, magnetic fields or particles, optical fields or particles, or any combination thereof.
[0101] Those of skill would further appreciate that the various illustrative logical blocks, modules, circuits, and algorithm steps described in connection with the embodiments disclosed herein may be implemented as electronic hardware, computer software, or combinations of both. To clearly illustrate this interchangeability of hardware and software, various illustrative components, blocks, modules, circuits, and steps have been described above generally in terms of their functionality. Whether such functionality is implemented as hardware or software depends upon the particular application and design constraints imposed on the overall system. Skilled artisans may implement the described functionality in varying ways for each particular application, but such implementation decisions should not be interpreted as causing a departure from the scope of the present invention.
[0102] The various illustrative logical blocks, modules, and circuits described in connection with the embodiments disclosed herein may be implemented or performed with a general purpose processor, a digital signal processor (DSP), an application specific integrated circuit (ASIC), a field programmable gate array (FPGA) or other programmable logic device, discrete gate or transistor logic, discrete hardware components, or any combination thereof designed to perform the functions described herein. A general purpose processor may be a microprocessor, but in the alternative, the processor may be any conventional processor, controller, microcontroller, or state machine. A processor may also be implemented as a combination of computing devices, e.g., a combination of a DSP and a microprocessor, a plurality of microprocessors, one or more microprocessors in conjunction with a DSP core, or any other such configuration.
[0103] The steps of a method or algorithm described in connection with the embodiments disclosed herein may be embodied directly in hardware, in a software module executed by a processor, or in a combination of the two. A software module may reside in RAM memory, flash memory, ROM memory, EPROM memory, EEPROM memory, registers, hard disk, a removable disk, a CD-ROM, or any other form of storage medium known in the art. An exemplary storage medium is coupled to the processor such the processor can read information from, and write information to, the storage medium. In the alternative, the storage medium may be integral to the processor. The processor and the storage medium may reside in an ASIC. The ASIC may reside in a user terminal. In the alternative, the processor and the storage medium may reside as discrete components in a user terminal.
[0104] The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the present invention. Various modifications to these embodiments will be readily apparent to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of the invention. Thus, the present invention is not intended to be limited to the embodiments shown herein but is to be accorded the widest scope consistent with the principles and novel features disclosed herein.
[0105] A portion of the disclosure of this patent document contains material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent document or the patent disclosure, as it appears in the Patent and Trademark Office patent file or records, but otherwise reserves all copyright rights whatsoever. | A method and system for a handoff in a broadcast communication system is disclosed. A subscriber assisted handoff is impractical in a broadcast communication system due to e.g., a high signaling load, a difficulty to synchronize the broadcast transmission. On the other hand, the small number of broadcast channels enables the subscriber station to perform the handoff autonomously. To streamline the autonomous handoff decision process, several distinct sets of pilot identifiers and rules for transitioning among the sets are defined. To fully integrate broadcast services with the services provided by the cellular telephone systems in a subscriber environment, a methods for various handoff scenarios are analyzed. | 7 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation of international patent application no. PCT/EP2009/007914, filed Nov. 5, 2009, designating the United States of America and published in German on May 14, 2010 as WO 2010/051990 A1, the entire disclosure of which is incorporated herein by reference. Priority is claimed based on European patent application no. EP 08019415.2, filed Nov. 6, 2008, which likewise is incorporated herein by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] The present invention relates to a sample carrier, for example a multi-well platform, with one or a plurality of recesses, in each of which a substance to be analyzed is located. The present invention furthermore relates to a method in which one or more substances, which are each located in a recess of a sample carrier, are aligned on a uniform plane relative to the surface of the sample carrier before being analyzed.
[0003] Analyses of substances in high throughput methods make it necessary to carry out reactions and/or analytical measurements in sample carriers having a plurality of recesses, in or on which the respective substance is located. One analysis method in this context is, for example, X-ray powder diffractrometry, which is a standard method when determining polymorphism. In this measurement, an X-ray beam is successively directed onto each substance on the sample carrier and the portion reflected thereby is evaluated. However, the analysis of substances in sample carriers of this type has the drawback that the results achieved thereby can only be compared with one another to a limited extent.
SUMMARY OF THE INVENTION
[0004] It was therefore the object of the present invention to provide a sample carrier with which analyses of substances located on or in the sample carrier can be carried out and which ensures very good comparability of the results achieved.
[0005] Another object of the invention was to provide an analysis method with which test substances can be analyzed to obtain analysis results with very good comparability.
[0006] These and other objects of the invention are achieved in accordance with the present invention by providing a sample carrier having a plurality of recesses, in each of which a substance to be analyzed is located, said sample carrier having means with which the substances to be analyzed can be aligned on the same plane relative to the sample carrier.
[0007] The sample carrier according to the invention is, for example, a so-called multi-well platform. The sample carrier has one or any desired plurality of recesses, in particular holes, which are preferably arranged in a uniform pattern, most preferably equidistantly. The recesses preferably extend through the entire thickness of the sample carrier. The recesses may have any cross-section, but are preferably circular. The recesses are preferably lined with a sleeve, in particular a sleeve to which the adhesion of the substances is as low as possible. For example, this is a Teflon sleeve. In another preferred embodiment each recess is coated, for example with a non-stick coating, and/or the entire sample carrier is made of an inert material, which particularly preferably also has non-stick properties.
[0008] In each of these recesses, a vessel is preferably arranged so as to be displaceable along the recess. For example, the vessel may be part of a plunger, in particular arranged on the upper side thereof. The plunger may be produced from glass, metal, in particular steel and/or plastics material. It may also have a non-stick coating. This vessel may be of any configuration. For example, it may be planar but also curved in a convex and/or concave manner. The substance to be analyzed is located, in each case, in the vessel and/or on the vessel. The height of the substance preferably extends at least to the upper edge of the vessel, at least at times but particularly preferably projects from it. The substance to be analyzed may in each case be placed on the vessel. However, the production of the respective substance preferably also takes place in the vessel, for example by reaction and/or a processing operation, so the vessel can also be configured as a production vessel. In this case, the production preferably takes place in a comparatively lowered state of the vessel within the sample carrier. The vessel may be produced from glass, metal, in particular steel, and/or plastics material. It may also have a non-stick coating.
[0009] According to the invention, the sample carrier has a means with which the substances to be analyzed can be aligned, in each case, on the same plane, in particular a horizontal plane, preferably above the sample carrier, relative to the surface of the sample carrier. This means is preferably a covering means, which covers one side of each recess. The respective substance is preferably moved, in particular displaced, before being analyzed, along the recess in the direction of the cover, which, for example, can take place using the above-described plunger, which is pressed against the vessel from below. The respective substance to be analyzed may, however, simply be poured into the respective recess; it then drops onto the cover and preferably remains suspended thereon, at least in part.
[0010] Thus, each substance and/or the respective vessel comes into contact with the covering means, so these are then all located in the same plane relative to the surface of the sample carrier. Accordingly, in the sample carrier according to the invention, all the substances, at least in partial regions, have the same position in relation to the surface of the sample carrier. The quality of the comparability of the analysis, for example in X-ray powder diffractometry measurement in reflection, is therefore increased.
[0011] The covering means preferably serves as a stop for the respective substance and/or the respective vessel. These are preferably pressed against the covering means and, in this case, particularly preferably pressed flat. The covering means is preferably provided in one piece and accordingly covers all the ends of the recesses present on one side of the sample carrier. The transmission of the covering means, in particular in relation to X-ray beams, is particularly preferably as high as possible. The covering means is preferably a film, in particular an X-ray permeable film. A film within the meaning of the invention has a thickness in the pm range. In another preferred embodiment, the covering means is a plate, in particular an X-ray permeable plate, which has a higher mechanical stability than a film, and in particular is not damaged or plastically deformed by the substances and/or the vessels.
[0012] A cross-contamination of the substances with one another can also be prevented by the covering means.
[0013] A spacer is preferably arranged between the sample carrier and the covering means. The covering means is then preferably arranged on this spacer, in particular reversibly. The covering means, in particular if it is a film, is particularly preferably glued to the spacer. The spacer has recesses, for example in the form of through-holes, which are arranged coaxially with the recesses of the sample carrier. The thickness of this spacer is preferably greater than the amount by which the sleeves arranged in the recesses of the sample carrier project from the surface of the sample carrier. A thickness of a few millimetres is generally sufficient. The area of the recess in the spacer is preferably equal to or greater than the area of the recess located therebelow in the sample carrier. In particular, the area of each recess in the spacer is so great that it can receive the outer edge of the sleeves which are located in the recesses in the sample carrier. As a result, the spacer does not rest on the edge of a sleeve, but directly on the respective surface of the sample carrier. If the substances are now moved precisely up to the outer edge of the spacer, where the covering means is located as a stop, they are all aligned precisely in the same plane relative to the surface of the sample carrier. With a horizontally orientated sample carrier, they are, for example, located precisely at the same height thereabove.
[0014] A counter means is preferably arranged on the side of the covering means remote from the sample carrier. This counter means in particular increases the mechanical loading capacity of the covering means and is in particular advantageous when the covering means is a film. The counter means is preferably fastened to the sample carrier in such a way that the covering means is located between the counter means and the sample carrier. The counter means ensures that the substances and/or the vessels do not damage the covering means when they are brought into contact with it. Owing to the counter means, the substances can be pressed against the covering means with a comparatively high force, without the covering means changing its position and/or being mechanically destroyed. The counter means can also serve as a stop for the substances and/or the vessels. For the actual analysis, the counter means is then preferably removed from the sample carrier.
[0015] The sample carrier according to the invention is suitable for any analysis, in particular, however, for high throughput screening and, in this case, in particular for analysing reflection measurements by means of X-ray powder diffractometry.
[0016] A further subject of the present invention is a method for analysing a plurality of substances which are each located in the recess of a sample carrier, in which the substances are aligned on a uniform plane relative to the sample carrier before being analyzed.
[0017] The alignment may take place by a manual or mechanical application of force and/or due to the action of gravity.
[0018] The statements made with regard to the sample carrier according to the invention apply equally to the method according to the invention and vice versa. The method according to the invention can be carried out, in particular, with the sample carrier according to the invention.
[0019] The recesses are preferably covered with a covering means. This covering means preferably serves as a stop for all the samples and/or the vessel on or in which they are located, but also serves to avoid cross-contamination of the substances with one another.
[0020] The substances are preferably made to rest on the covering means, preferably pressed against it.
[0021] In a preferred embodiment, the substances to be analyzed are each located in and/or on a vessel which is longitudinally displaceably arranged in a recess of the sample carrier in each case, these vessels being moved, in each case, in the direction of the covering means prior to the analysis of the substances, until the substance and/or the vessel touches the covering means in each case.
BRIEF DESCRIPTION OF THE DRAWINGS
[0022] The invention will be explained in further detail hereinafter with reference to illustrative embodiments depicted in the accompanying FIGS. 1 to 5 . These embodiments are merely examples of the invention and do not limit the general concept of the invention. The following explanations apply equally to the apparatus and method of the invention. In the drawings:
[0023] FIG. 1 shows a sample carrier, in this case a multi-well platform;
[0024] FIG. 2 shows a plunger with a vessel;
[0025] FIG. 3 shows a spacer;
[0026] FIG. 4 shows the counter plate; and
[0027] FIG. 5 shows the sample carrier prior to the measurement.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0028] FIG. 1 shows the sample carrier 1 according to the invention in two views. In this case, this is a multi-well plate. It has a plurality of through-holes 2 , in this case 96 , which thus extend over the entire thickness D of the sample carrier. The holes 2 are equidistantly arranged in a uniform pattern. Each hole is lined with a Teflon sleeve 8 , which projects beyond the surface 1 . 1 of the sample carrier by a specific amount, with this amount varying, but generally not exceeding a maximum of 2 mm. The Teflon sleeve has an external diameter 8 . 1 at its upper end. A plunger 9 , shown in FIG. 2 , is arranged in each of these Teflon sleeves 8 . The plunger consists of steel and/or Teflon and, at its upper end, has a preferably planar glass plate 3 , namely the vessel on which the substance 4 to be analyzed is arranged and/or on which the substance to be analyzed is produced. The diameter of the plunger 9 and the vessel 3 is such that the plunger can be displaced within the sleeve using a moderate application of force.
[0029] FIG. 3 shows the spacer 5 , which also has a plurality of through-holes 5 . 1 , the arrangement of which corresponds to the arrangement of the holes 2 in the sample carrier, so the centre point of the holes 2 , 5 . 1 is flush when the spacer 5 is placed on the sample carrier 1 . The diameter 5 . 2 of the holes 5 . 1 is selected in such a way that it is at least equal to, preferably slightly greater than, the external diameter of the sleeves 8 , so the upper end thereof can be received by the recesses 5 . 1 . The spacer 5 can be connected to the sample carrier by means of four screws in the corner region 5 . Once the spacer 5 has been placed on the sample carrier 1 , no sleeve edge projects beyond the surface of the spacer.
[0030] A covering means 6 , in this case a film, preferably an X-ray permeable film, for example the film with the commercial name Ultraphan, is now glued to the spacer 5 . A water-soluble adhesive has proven successful as the adhesive. The surface of the spacer 5 is coated with the adhesive, at least in portions, and then the film 6 is glued thereon.
[0031] The counter plate 7 , which is shown in FIG. 4 , is then fastened, for example screwed, onto the spacer to which the film has been glued.
[0032] The substances are analyzed as follows. A respective substance 4 is placed on the vessel 3 of a sample carrier or produced therein. The vessels 3 and the plungers 9 are located, in this case, in a comparatively lowered position. Thereafter or beforehand, the spacer 5 to which a film 6 has been glued is fastened to the surface 1 . 1 of the sample carrier 1 . The counter plate is applied thereon. The sample carrier, together with the spacer 5 , film 6 and counter plate 7 , is then rotated through 180°, so the counter plate points downwards. The plungers 9 and therefore the vessels 3 are then displaced manually or mechanically in the direction of the covering means 6 , until the edge 3 . 1 of the vessels 3 rests in each case on the covering means 6 . The counter plate 7 prevents the film 6 being damaged, in particular over-extended, by the vessels 3 . The counter plate, however, also serves as a stop for the vessels/plungers, so the edge 3 . 1 of all the vessels and the position of the substances 4 after the displacement of the plungers have exactly the same position relative to the surface of the sample carrier 1 , i.e. the substances 4 and/or the edge 3 . 1 then all have the same spacing from the surface 1 . 1 of the sample carrier. The substances 4 may partially adhere to the film 6 in part. Thereafter, the sample carrier is rotated back through 180° and the counter plate 7 is now removed from the sample carrier 1 and the sample carrier is fastened, preferably horizontally, on an analysis instrument and the analysis is carried out substance by substance. The substances all have the same height and this is advantageous for the comparability of the measurements.
[0033] The person skilled in the art will understand that the counter plate 7 can be dispensed with if, for example, the covering means itself has such an adequate mechanical stability that it is not damaged or plastically deformed by the substances and/or the vessels.
[0034] The plungers/vessels can be omitted if the respective substance to be analyzed adheres to the covering means. In this case, the sample carrier provided with the covering means, as described above, only has to be aligned with the covering means downwardly and the respective substance to be analyzed must only be poured into a hole in each case, which substance then drops onto the covering means and adheres there. The sample carrier can then be rotated back again and the analysis carried out.
[0035] FIG. 5 shows the sample carrier after the alignment. It can clearly be seen how the substances adhere to the film 6 , which is glued to the spacer 5 . All the substances are located at the same height.
[0036] The foregoing description and examples have been set forth merely to illustrate the invention and are not intended to be limiting. Since modifications of the described embodiments incorporating the spirit and substance of the invention may occur to persons skilled in the art, the invention should be construred broadly to include all variations within the scope of the appended claims and equivalents thereof.
LIST OF REFERENCE NUMERALS
[0037] 1 sample carrier, multi-well plate, multi-well platform
[0038] 1 . 1 surface of the sample carrier
[0039] 2 recess, hole
[0040] 3 vessel, reaction vessel, glass plate
[0041] 3 . 1 upper edge of the reaction vessel
[0042] 4 substance to be analyzed
[0043] 5 spacer, perforated plate
[0044] 5 . 1 recesses in the spacer, through-hole
[0045] 5 . 2 diameter, area of the recess
[0046] 6 covering means, cover, film
[0047] 7 counter means, counter plate
[0048] 8 lining, sleeve, Teflon sleeve
[0049] 8 . 1 area, diameter of the sleeve
[0050] 9 plunger
[0051] D thickness of the sample carrier | A sample carrier such as a multi-well platform with one or more recesses, in each of which a substance to be analyzed is disposed, and an analysis method in which one or more substances, each of which is located in a recess of the sample carrier, are aligned on a uniform plane relative to the surface of the sample carrier before being analyzed. | 1 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an impregnating carbonizing process and apparatus for impregnating a porous shaped body of carbon with tar pitch or resin and carbonizing the tar pitch or resin to produce a carbon material of a high density.
2. Description of the Prior Art
In recent years, composite materials of carbon fiber and carbon materials (hereinafter referred to as C/C composite materials) have come into wide use as new materials in the aerospace and aircraft work for rocket nozzles, aircraft brakes and so forth. Further, attention is paid also to application of such C/C composite materials as a structural material for a high temperature furnace or a tray material which is used in an inert atmosphere because they have characteristics that they are light in weight and high in strength and have a small heat capacity and that they are high in impact strength.
Also with regard to conventional graphite materials, the quality has been improved in recent years, and the demand is increasing for fine materials which are fine in crystal grain and small in quantity of pores.
However, one of the greatest technical subjects in production of such carbon materials resides in how to attain a high density. Particularly, establishment of a technique of achieving a high density in an industrial scale, that is, establishment of a technique of mass production of carbon materials of a high density, is a serious subject.
As a technique of improving the high density of such materials, conventionally a process is employed wherein a porous shaped body is impregnated with a carbonizable substance such as tar pitch or resin and then the carbonizable substance is carbonized. Normally, a porous shaped body is impregnated in vacuum and then baked under the atmospheric pressure.
As a technique of impregnating a porous shaped body with tar pitch in vacuum and carbonizing the tar pitch under a pressure of high pressure gas, such a technique, for example, as illustrated in FIG. 5 is already known. The object of the technique is a C/C composite material, and an original shaped body consists mainly of carbon fiber. Referring to FIG. 5, a shaped body 1 is inserted into a vacuum vessel 2, and then, the shaped body 1 is impregnated with tar pitch in vacuum at a temperature of 200 C. After such impregnation, the shaped body 1 is inserted into a baking furnace 3 in which it is heated to a temperature of 850 C. under the atmospheric pressure to carbonize the tar pitch. Then, the outer face of the shaped body thus obtained is roughened, and then, it is inserted into an airtight can 4 together with tar pitch and impregnated with the tar pitch in vacuum again, whereafter the can 4 is sealed to maintain the inside of the can 4 in a vacuum condition. Subsequently, the thus sealed can 4 is inserted into a high temperature, high pressure furnace 5 in which a pressure of argon gas is applied to the can 4 to heat and pressurize the shaped body 1. Thus, the shaped body 1 is carbonized finally in the conditions of a temperature of 650 C. and a pressure of 10,000 psi (about 700 kg/cm 2 ). After such carbonization, the can 4 is removed from the furnace 5, and the shaped body 1 is inserted into a high temperature furnace 6 and heated to a temperature of 2,700 C. to graphitize the shaped body 1.
When tar pitch is heated and carbonized in an atmosphere of inert gas such as argon gas under a high pressure, carbon produced at the heating carbonizing step may possibly stick to an energizable member such as a heater to cause a damage to insulation or a short-circuiting accident of the energizable member. In order to prevent such possible trouble, the method which employs such a can 4 for enclosing tar pitch therein as described above or another method which employs a specimen case is adopted. The latter method is disclosed, for example, in Japanese Patent Laid-Open No. 62-84291 and Japanese Utility Model Laid-Open No. 63-57500. As an example wherein a specimen case is employed, an apparatus which is disclosed in Japanese Laid-Open No. 62-84291 is shown in FIG. 6.
Referring to FIG. 6, a high pressure vessel 101 has an upper lid 102 and a lower lid 103 fitted in upper and lower openings thereof. The fitted portions of the high pressure vessel 101 with the upper and lower lids 102 and 103 are held in an airtight condition by a pair of seal members 104 and 104', respectively, and a high pressure chamber 105 is defined in the high pressure vessel 101. A pressure of gas acting upon the lids 102 and 103 is supported by a press frame (not shown), and a pair of heating members 106 and 106' and a heat insulating layer 108 are disposed in the inside of the high pressure vessel 101. The heating members 106 and 106' are each composed of an electric heating resistor wire for heating a work 112 to be processed and have a tubular holder 107. The heat insulating layer 108 is provided to restrain heat from being transmitted from the heating members 106 and 106' to the high pressure vessel 101 and the upper and lower lids 102 and 103.
An airtight chamber 115 is formed in a processing chamber 109 on the inner sides of the heating members 106 and 106' and partitioned by an impermeable partition wall 113.
In the case of the apparatus shown in FIG. 6, the airtight chamber 115 is defined by a tube of an inverted cup shape connected uprightly to the lower lid 103 in an airtight relationship by means of a seal member 114.
Generally, the tubular partition wall 113 is preferably made of a metal material such as stainless steel, inconel, molybdenum or tungsten in order to assure the impermeability to gas. However, depending upon a temperature requirement, it is also possible to employ an inorganic material such as impermeable graphite.
The work 112 to be processed is removably inserted into the airtight chamber 115 of the tubular partition wall 113 by way of a furnace floor 111. Further, the partition wall 113 is provided with a check valve 116 which establishes communication between the inside and the outside of the airtight chamber 115 to permit gas to flow from the outside into the inside of the airtight chamber 115 but prevent gas to flow from the inside to the outside of the airtight chamber 115.
In order to assure a valve function of the check valve 116, a seal member such as an O-ring is sometimes used for the valve section. From the point of view of heat resistance of a spring of the check valve 116, the check valve 116 is preferably disposed at a lower location of the airtight chamber 115 at which the temperature is comparatively low.
According to circumstances, the check valve 116 may be provided in a duct line system which is provided in the inside of the lower lid 103 constituting part of the partition wall for establishing communication between the inside and the outside of the airtight chamber 115.
In the apparatus shown in FIG. 6, duct lines 117, 118 and 119 for communicating the airtight chamber 115 to the outside of the high pressure vessel are formed in the lower lid 103, and an opening and closing valve 120 is provided in the duct line 118.
A further duct line 124 is formed in the lower lid 103 and communicates with the processing chamber 105, and the opening and closing valve 120 is moved to an open position in response to an electric signal from a pressure difference detector 125 which is connected to the duct line 124 and the duct line 119 in the lower lid 103.
Subsequently, a processing method with the apparatus shown in FIG. 6 and functions of the individual members for such processings will be described.
The gas in the inside of the processing chamber 105 of the high pressure vessel 101 is discharged, for example, by way of a duct line 110 formed in the upper lid 102 by means of a vacuum pump (not shown), and after then, inert gas such as argon gas is introduced into the processing chamber 105 similarly by way of the duct line 110.
In this instance, while the outside of the airtight chamber 115 can be put into a vacuum condition by such discharging of the internal gas, the inside of the airtight chamber 115 cannot be put into a vacuum condition due to the presence of the check valve 116. Therefore, in order to discharge the gas from the inside of the airtight chamber 115 until a vacuum condition is reached, the duct lines 117 and 118 in the lower lid 103 are used.
Also in the inert gas introducing operation, it is advantageous to introduce gas by way of the duct line 110 in the upper lid 102 while the duct lines 117 and 118 in the lower lid 103 are utilized to discharge the internal gas in order to accomplish replacement of gas in the airtight chamber 115 perfectly.
After water or oxygen which is bad for materials of the components of the apparatus or the work 112 to be worked is removed by such air discharging and gas introducing operations, argon gas is sent into the inside of the processing chamber 105 to a predetermined pressure by way of the duct line 110.
After the pressure medium gas is filled fully into the processing chamber 105, power is supplied to the heating chambers 106 and 106' to heat the work 112. In this instance, however, the rise in pressure when the temperature rises is greater on the inside of the airtight chamber 115 than on the outside of the airtight chamber 115. Accordingly, an excessive amount of the internal pressure may be discharged outside the high pressure vessel 101 by opening the opening and closing valve 120.
The opening and closing valve 120 is opened in response to an electric signal which is delivered from the pressure difference detector 125 when the difference between the external pressure and the internal pressure of the airtight chamber 115 which is detected by the pressure difference detector 125 reaches a predetermined value.
On the other hand, an improved technique of an HIP (hot isostatic pressing) equipment is disclosed in Japanese Patent Publication No. 58-46524 though not used for impregnation nor carbonization of a carbon material.
The prior art is intended for application to a hot isostatic pressing method for shaping and sintering powder, a method for processing a material for a sintered tool at a high temperature under a high pressure or a high pressure bonding method for bonding a turbine blade to a turbine body. The improved HIP equipment is constructed such that a heat insulating layer, a heater, a work to be processed and a lower lid may be removed in an integral relationship from a high pressure vessel, and a pre-heating operation can be performed outside the HIP equipment without occupying the expensive high pressure vessel. In particular, with the improved HIP equipment, in order to reduce the cycle time of the HIP processing, a work to be processed is placed in advance on the lower lid outside the HIP vessel, and the heater and the heat insulating layer are set in position around the work. In this condition, the heater is energized to pre-heat the same before the work is inserted into the high pressure vessel of the HIP equipment, and after such pre-heating, the work, lid, heater and heat insulating layer are set in position in an integral relationship into the high pressure vessel of the HIP equipment. Consequently, the time required for raising the temperature of the work in the high pressure vessel of the HIP equipment to a predetermined level can be reduced.
The prior art equipments described above, however, have the following drawbacks. In particular, with the arrangement shown in FIG. 5 wherein the shaped body 1 is enclosed in the can 4, the can 4 is contracted and deformed to disable re-use thereof because a pressure of up to 700 kgf/cm 2 is finally applied to the shaped body 1 from the outside of the can 4. Therefore, it is necessary to produce a new can 4 each time the processing described above is to be performed. Accordingly, the cost of consumable goods is increased due to production of such can 4. Further, the expense for sealing operation is also required. Thus, the prior art requires a high processing cost.
Besides, in the process wherein tar pitch is carbonized, gas such as hydrocarbon or hydrogen is generated. Then, if the pressure within the can is increased by the gas thus generated and finally exceeds a pressure of argon gas outside the can, the can may be swollen and broken. In order to prevent this, it is necessary to cause the hydrocarbon in the can to be decomposed rapidly into carbon and hydrogen and raise the temperature while waiting for the hydrogen to be diffused into a wall of the can and pass through the same to the outside of the can. Accordingly, there is a drawback that a long period of time is required for a required temperature rise.
Meanwhile, with the prior art disclosed in Japanese Patent Laid-Open No. 62-84291 and Japanese Utility Model Laid-Open No. 63-57500 wherein a specimen case is used, a series of operations (steps) of melting tar pitch and impregnating a porous shaped body with the tar pitch are performed in the high pressure vessel also as apparently seen from FIG. 6. Then, when the tar pitch is melted, it is heated to a temperature of 200 to 300 C. However, the heat conductivity of tar pitch is as low as a level of that of a resin. Accordingly, a very long period of time is required until the tar pitch is melted, and consequently, the utilization efficiency of the expensive high pressure vessel is very low. In the case of, for example, a specimen having a diameter greater than 20 cm, 10 to 20 hours are required.
To the contrary, the prior art disclosed in Japanese Patent Publication No. 58-46524 is not suitable to impregnate a porous shaped body with tar pitch and carbonize the tar pitch. Thus, in order to perform an impregnating operation at first, it is necessary to heat tar pitch into a molten condition in vacuum. However, since the heater and the work to be processed are disposed in the same spacing, components which will be gasified at a heating and melting step (low boiling point components) will stick to the heater and so forth, which may cause a damage to insulation. Accordingly, the prior art cannot be used actually.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an impregnating carbonizing method and apparatus which permit reduction in cost of consumable goods and can operate at a reduced cost.
It is another object of the present invention to provide an impregnating carbonizing method and apparatus wherein a heating and vacuum impregnating operation which requires a very long period of time can be performed on the outside of an expensive high pressure vessel to accomplish rapid carbonization and baking.
In order to attain the objects, according to one aspect of the present invention, there is provided an impregnating carbonizing process which comprises the steps of inserting a porous shaped body of carbon and a block of impregnant into a specimen case which has a gas admitting valve which is opened to admit gas from the outside into the inside of the specimen case when a predetermined difference in pressure is caused between the outside and the inside of the specimen case and which further has a gas discharging opening for discharging the internal gas of the specimen case therethrough, discharging, at a reduced pressure impregnating station, gas from the inside of the specimen case by way of the gas discharging opening of the specimen case, heating the impregnant from the outside of the specimen case to melt the impregnant under a reduced pressure to dip the shaped body of carbon in the molten liquid of the impregnant, inserting the specimen case into a high pressure vessel at a high pressure impregnating carbonizing station, admitting gas of a high pressure into the high pressure vessel until the high pressure gas is admitted into the specimen case by way of the gas admitting valve so as to penetrate the impregnant into the shaped body of carbon under the pressure of the high pressure gas, heating the shaped body to a high temperature, and discharging the high pressure gas by way of the gas discharging opening to lower the pressure within the specimen case at a controlled rate in response to a pressure within the high pressure vessel to carbonize part or the entirety of the impregnant.
With the process, the reduced pressure impregnating step, pressurizing impregnating step and carbonizing baking step are performed successively in this order, and the reduced pressure impregnating step is carried out at the reduced pressure impregnating station, and the other two steps are carried out at the pressurizing impregnating and carbonizing station. At the reduced pressure impregnating station, the gas in the specimen case is discharged outside by way of the gas discharging opening, and the specimen case is heated from the outside. Consequently, the impregnant in the specimen case is heated into a molten condition under a reduced pressure so that it may be penetrated into pores of the porous shaped body of carbon in vacuum.
In this instance, since the reduced pressure impregnating step is performed outside the high pressure vessel, the high pressure vessel is not occupied by the porous shaped body of carbon for a long period of time although a long period of time is required for melting of the impregnant.
Further, since the specimen case is heated from the outside and is disconnected from the outside except at the gas discharging opening and the gas admitting valve and the gas discharging opening is connected to the pressure reducing means while the gas admitting valve prevents gas from flowing out of the specimen case, gas generated in the sample case will not cause such a trouble as damage to insulation.
After completion of the reduced pressure impregnating step, the specimen case is transported to the pressurizing impregnating and carbonizing station and placed into the high pressure vessel.
At the pressurizing impregnating and carbonizing station, at first gas is supplied into the high pressure vessel. The gas is admitted into the specimen case by way of the gas admitting valve. Consequently, the pressure of the gas acts directly upon a free surface of the molten liquid of the impregnant so that the impregnant is caused to penetrate into the porous shaped body of carbon under pressure.
Subsequently, the specimen case is heated from the outside by means of the heater disposed in the high pressure vessel so that carbonizing baking is carried out in a high pressure, high temperature condition.
In this instance, there is a tendency for the internal pressure of the specimen case to become higher than the external pressure of the specimen case. This is because gas is generated as such carbonizing baking proceeds.
Accordingly, there is the possibility that the specimen case may be swollen or broken by the internal pressure. According to the process of the present invention, however, since the internal gas is discharged by way of the gas discharging opening to lower the internal pressure of the specimen case at a controlled rate, there is no such possibility as described just above. Accordingly, the specimen case can be used several times repetitively. Consequently, the cost of consumable goods can be reduced, and the processing cost can be reduced.
Thus, with the process of the present invention, the occupation time of the high pressure vessel in one impregnating carbonizing cycle is reduced as the impregnant melting operation and the vacuum impregnanting operation are carried out outside the high pressure vessel, and the high pressure vessel is utilized effectively only at a step at which a high pressure processing is required. Consequently, the productivity is improved remarkably.
Further, since the pressurizing impregnating operation is carried out in addition to the vacuum impregnating operation and the impregnant is carbonized and baked under a high pressure, the yield of carbon is high, and accordingly, a carbon material can be produced at a high efficiency. Further, the specimen case can be used repetitively, which can reduce the processing cost. In addition, at either of the reduced pressure impregnating station and the pressurizing impregnating and carbonizing station, the inside of the specimen case is communicated with the outside by way of the gas discharging opening such that, at the reduced pressure impregnating station, the internal pressure of the specimen case is lowered, and at the pressurizing impregnating and carbonizing station, the internal pressure is reduced at a controlled rate. Consequently, gas generated in the specimen case will not flow out to the heater section, and accordingly, no damage to insulation will be caused at all.
According to another aspect of the present invention, there is provided an impregnating carbonizing apparatus which comprises a reduced pressure impregnating station, a high pressure impregnating carbonizing station, and a specimen case adapted to be supplied successively to the reduced pressure impregnating station and the high pressure impregnating carbonizing station and adapted to receive therein a porous shaped body of carbon and a block of impregnant, the specimen case having a gas admitting valve which is opened to admit gas of the outside of the specimen case into the inside of the specimen case when a predetermined difference in pressure is caused between the outside and the inside of the specimen case, the specimen case further having a gas discharging opening for discharging internal gas of the specimen case therethrough, the reduced pressure impregnating station including a bell-shaped furnace which is opened at a lower portion thereof so that the specimen case can be contained therein, a support table for supporting the specimen case thereon, and a pressure reducing means communicated with the gas discharging opening of the specimen case for discharging internal gas of the specimen case therethrough to lower the internal pressure of the specimen case, the high pressure impregnating carbonizing station including a high pressure vessel, a pair of upper and lower lids for closing openings at the opposite ends of the high pressure vessel, a heat insulating layer disposed in the high pressure vessel, a high pressure heating means disposed on the inner side of the heat insulating layer, and a control valve communicated with the gas discharging opening of the specimen case for lowering the internal pressure of the specimen case at a controlled rate.
With the impregnating carbonizing apparatus of the present invention, the cost of consumable goods is reduced, and the impregnating carbonizing process can be accomplished rapidly at a reduced cost. Consequently, production of high density carbon materials by the impregnating carbonizing process which makes use of a pressure of high pressure gas is enabled at an industrial level. Thus, the present invention exhibits a remarkable contribution to the field of carbon materials.
The above and other objects, features and advantages of the present invention will become apparent from the following description and the appended claims, taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic sectional view of a pressurizing impregnating station with which an impregnating carbonizing process according to the present invention is carried out;
FIG. 2 is a schematic sectional view of a specimen case for use with an impregnating carbonizing apparatus to which the present invention is applied;
FIG. 3 is a diagrammatic representation showing an impregnating carbonating apparatus to which the present invention is applied;
FIG. 4 is a graph showing a relationship between a pressure and a yield of carbon produced by the impregnating carbonating apparatus shown in FIG. 3;
FIG. 5 is a diagrammatic representation illustrating a conventional impregnating carbonizing process; and
FIG. 6 is a schematic sectional view showing a conventional impregnating carbonizing apparatus.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring first to FIG. 1, there is shown a pressurizing impregnating station of an impregnating carbonizing apparatus according to which the present invention is applied. The pressurizing impregnating station includes a specimen case 11 having a lid 12 mounted in an airtight relationship at the top thereof. The specimen case 11 has a gas admitting valve 13 disposed in a side wall thereof.
The gas admitting valve 13 is opened when the difference between the external pressure and the internal pressure of the specimen case 11 becomes greater than a predetermined value, and when the gas admitting valve 13 is open, gas of the outside is introduced into the inside of the specimen case 11. The specimen case 11 has a gas discharging opening 14 formed therein, and a pipe 17 is connected to the gas discharging opening 14. The pipe 17 is communicated either with the atmospheric air or with a suitable gas discharging location (not shown). Thus, gas in the specimen case 11 is discharged through the gas discharging opening 14 by way of the pipe 17. It is to be noted that a control valve 18 is interposed intermediately in the pipe 17.
Meanwhile, the specimen case 11 is adapted to be inserted in its entirely into a high pressure vessel 25. A pair of lids 16 and 16' each in the form of layered plate are mounted in an airtight relationship at the longitudinal opposite ends of the high pressure vessel 25, and the pipe 17 extends through the lower lid 16 and is connected to the gas discharging opening 14. Further, the upper lid 16' has a high pressure gas admitting opening 19 perforated therein, and a pipe 20 is connected to the gas admitting opening 19. The pipe 20 is further connected to a supply source of high pressure argon (Ar) gas. Accordingly, high pressure argon gas can be introduced into the high pressure vessel 25 by way of the gas admitting opening 19. Another pipe 21 is connected to and extends between the pipes 17 and 20, and a check valve 22 is interposed intermediately in the pipe 21 for preventing gas from flowing from the pipe 20 side to the pipe 17 side. A control valve 23 is also provided intermediately in the pipe 21.
A heater 24 is disposed in the high pressure vessel 25 in such a manner as to surround the specimen case 11, and a work in the specimen case 11 is heated in the high pressure vessel 25 by the heater 24.
According to the process of the present invention, at first a container in which a shaped body 8 of carbon and a solid block 9 of an impregnant such as resin or tar pitch are contained is placed into the specimen case 11, and then, the lid 12 is mounted in an airtight relationship at the top of the case 11. Then, the entire case 11 is inserted into the high pressure vessel 25, and the lid 16 is fitted in an airtight relationship to the high pressure vessel 25 while at the same time an end of the pipe 17 is connected to the gas discharging opening 14 of the lid 12. It is to be noted that the pipe 17 is attached in advance to the lid 16.
After the various members are set in position in this manner, the control valve 18 is brought into an open position and air in the specimen case 11 is discharged outside by means of a suitable vacuum pump (not shown), whereafter the inside of the case 11 is maintained in the reduced pressure condition. Then, the heater 24 is rendered operative to heat the impregnant 9 in the specimen case 11 to raise the temperature of the impregnant 9 to about 200° to 300° C. at which the impregnant 9 is melted. Consequently, the impregnant 9 is put into a condition of molten liquid.
Subsequently, the control valve 18 is brought into a closed condition, and argon gas of a high pressure is introduced into the high pressure vessel 15 by way of the pipe 20. Consequently, the high pressure vessel 15 is filled with argon gas of a high pressure, and if the difference between the internal pressure and the external pressure of the specimen case 11 exceeds a predetermined level, then argon gas of the high pressure is admitted into the specimen case 11 by way of the gas admitting valve 13. Consequently, the pressure of the argon gas acts directly upon a free surface of the molten liquid of the impregnant 9 in the specimen case 11 so that the impregnant 9 penetrates even into fine pores of the porous shaped body 8 of carbon to impregnate the shaped body 8 sufficiently with the impregnant 9.
After such impregnating step, the impregnant 9 is heated to gradually raise its temperature by the heater 24 to carbonize the impregnant 9 which is tar pitch or the like. At the carbonizing baking step, gas is produced in the specimen case 11, and if the pressure within the specimen case 11 should rise suddenly, then the valve 18 should be opened to suitably discharge the gas from within the specimen case 11 by way of the gas discharging opening 14.
By carbonizing and baking the shaped body 8 of carbon in this manner and then graphitizing it by an ordinary method, a C/C composite material of a high density is produced.
As described above, in the present embodiment, a pressure of gas is caused to act directly upon a free surface of molten liquid of impregnant such as tar pitch to impregnate a shaped body of carbon with the impregnant by the action of the high pressure gas. Further, the porous shaped body of carbon is baked directly in the high pressure gas atmosphere while the partial pressure of the gas of hydrocarbon and so on produced by a carbonizing reaction is maintained at a high level at the carbonizing step. Consequently, as distinct from the conventional process wherein a can is consumed each time a processing of an impregnating carbonizing step is carried out, according to the process of the present invention, the specimen case can be used several times repetitively. Accordingly, the processing cost can be reduced remarkably.
Further, in the present embodiment, in case the pressure of gas which is generated upon carbonization becomes too high, the gas can be discharged to the outside by way of the gas discharging opening. Accordingly, the specimen case will not be swollen by such gas. Consequently, in the apparatus of the present invention, the temperature can be raised at a high rate without a trouble, and the processing can be performed rapidly.
It is to be noted that, since an impregnant of tar pitch or resin is normally in the form of a solid block at a room temperature, it is necessary to heat the impregnant into a molten condition. In the embodiment described above, while the melting step of the solid impregnant is achieved by operation of the heater 24 in the high pressure vessel 15, a long period of time is required for such temperature rise because the heat conductivity of the impregnant is low. Consequently, the period of time for which the high pressure vessel 15 is occupied for a melting operation of the impregnant is long.
Thus, if the step of melting the impregnant 9 in a reduced pressure condition for vacuum impregnation is performed by another heating furnace outside the high pressure vessel 15 and then the specimen case 11 in which the impregnant in the molten condition is contained is put into the high pressure vessel 15, then the period of time for which the high pressure vessel 15 is occupied can be reduced. Consequently, the productivity will be improved.
FIG. 2 shows a specimen case which used in an impregnating carbonizing apparatus to which the present invention is applied, and such impregnating carbonizing apparatus is schematically shown in FIG. 3. Referring to FIGS. 2 and 3, a specimen case 30 made of a metal material includes a cup 31 in the form of a tube closed at an upper end thereof and opened at lower end thereof, and a vessel 32 opened at an upper end thereof. A lower end portion of the cup 31 is fitted with an upper end portion of the vessel 32 with a seal ring 33 interposed therebetween so that the cup 31 and the vessel 32 are connected in an airtight relationship to each other. It is to be noted that the vessel 32 is secured to the cup 31 by means of a plurality of pins 34 so that it may not be pulled off from the latter.
At least one gas admitting valve 35 is provided at an upper portion of the vessel 32 of the specimen case 30. The gas admitting valve 35 is opened in response to a difference between the external pressure and the internal pressure of the case 30 to permit argon gas of a high pressure to flow into the inside of the case 30 from the outside in order to fill the specimen case 30 with the high pressure argon gas at an impregnating carbonizing step. Further, a gas discharging opening 36 is formed at a lower portion of the vessel 32 for suitably discharging gas within the case 30 so that the pressure of the gas within the case 30 may not be increased to an excessively high level. A valve 37 is disposed at the gas discharging opening 36. A valve body 37a of the valve 37 is normally urged downwardly by a spring 37b to normally close the gas discharging opening 36. Only when a vacuum discharging port 65 or a gas port 68 which will be hereinafter described is inserted into the gas discharging opening 36 to push the valve body 37a to move upwardly against the urging force of the spring 37b, the valve 37 is opened to establish communication between the inside of the specimen case 30 and the port 65 or 68.
A container 39 is in the form of a cup-shaped vessel, for example, made of a metal material, and the container 39 is adapted to receive therein a porous shaped body 8 of carbon and a solid block 9 of impregnant such as tar pitch or resin.
A holding member 40 is secured at an upper end portion of the container 39 by means of a clamp 41. The holding member 40 has a plurality of holes 42 formed therein so as to permit the impregnant 9 to pass therethrough but prevent passage of the shaped body 8 of carbon therethrough. Accordingly, the holding member 40 has a function to prevent such situation that the shaped body 8 of a light weight may float in molten liquid of the impregnant 9 and be partially exposed outside from within the impregnant 9 to disable impregnation by application of a pressure of gas which will be hereinafter described.
A hanging ring 43 is mounted at the top of the cup 31 so that the specimen 30 may be hung at the hanging ring 43 thereof and moved to an arbitrary position by means of a crane or the like.
Meanwhile, as shown in FIG. 3, a bell-shaped furnace 61 as a reduced pressure heating furnace and a support table 64 are disposed at a reduced pressure impregnating station A on the floor for the impregnating carbonizing apparatus. A vacuum discharging port 65 is disposed uprightly at the center of the support table 64 with a suction opening thereof directed upwardly. The port 65 is connected to a vacuum pump 60 by way of a discharging path provided in the support table 64. A recess 64a is formed on an upper wall of the support table 64 for receiving the specimen case 30 therein.
The bell-shaped furnace 61 is lined with a heat insulating member 63, and a heater 62 is disposed on the inner side of the heat insulating member 63. A crane 67 is disposed on the ceiling of the apparatus, and a hanging ring 66 is mounted at the top of the bell-shaped furnace 61. Consequently, the bell-shaped furnace 61 can be moved by lifting the same at the hanging ring 66 thereof by means of the crane 67.
Meanwhile, a high pressure vessel 50 is mounted on a support post 51 provided uprightly on the floor of the impregnating carbonizing apparatus at a pressurizing impregnating and carbonizing station B. The high pressure vessel 50 includes a high pressure tube 52 having its axis directed vertically, an upper lid 53 in the form of a disk placed at an upper end of the high pressure tube 52, a lower outer lid 54 secured to a lower end of the high pressure tube 52, and a lower inner lid 55 formed as a separate member from the lower outer lid 54 but adapted to be integrated with the lower outer lid 54 when the high pressure vessel 50 is to be used.
Further, a heat insulating layer 71 is disposed on inner faces of the high pressure tube 52 and the upper lid 53. A heating device 69 is disposed on the inner side of the heat insulating layer 71. The heating device 69 is composed of a pair of tubular heaters 70 disposed with their axes directed vertically. It is to be noted that, though not shown, also the high pressure vessel 50 is constructed similarly to the high pressure vessel 15 shown in FIG. 1 such that high pressure argon gas can be admitted into and vacuum can be discharged from the inside of the high pressure vessel 50.
A pit 58a is formed in the floor at the pressurizing impregnating and carbonizing station B, and a rail 58 is provided in the pit 58a such that it may interconnect a location just below the high pressure vessel 50 and another location (retracted position) spaced from the former location. The lower inner lid 55 of the high pressure vessel 30 is placed on a transport bogie 57, and in this condition, the transport bogie 57 is moved back and forth along the rail 58. A gas port 68 is provided uprightly at the center of the lower inner lid 55 with a suction port thereof directed upwardly. The gas port 68 is connected to a suitable pipe by way of a hole formed in the lower inner lid 55. Then, by operating a valve 68a provided for the pipe, the gas port 68 is communicated with or disconnected from the atmospheric air. A lifting device 59 is disposed at the location in the pit 58a just below the high pressure vessel 50, and when the transport bogie 57 is positioned at the location just below the high pressure vessel 50, the lifting device 59 can move the lower inner lid 55 on the transport bogie 57 upwardly and downwardly. When the lower inner lid 55 is moved up to its upper limit position by the lifting device 59, the lower inner lid 55 is fitted in an airtight relationship into the lower outer lid 54 of the high pressure vessel 50.
Further, a press frame 56 in the form of an angular ring is disposed on the floor of the pressurizing impregnating and carbonizing station B with its axis directed horizontally. The press frame 56 is moved back and forth on a rail 56a provided on the floor.
Operation of the impregnating carbonizing apparatus having such a construction as described above will be described in the following.
At first, the pins 34 of the specimen case 30 shown in FIG. 2 are removed and the cup 31 and the vessel 32 are separated from each other. Then, the container 39 in which a solid block 9 of impregnant and a porous shaped body 8 of carbon are contained is inserted into the cup 31 of the specimen case 30. In this instance, the shaped body 8 is disposed in a region which is surrounded by the holding member 40 and the container 49 below the holding member 40.
Subsequently, an upper end portion of the vessel 32 is inserted into a lower end portion of the cup 31, and the vessel 32 is secured to the cup 31 by means of the pins 34. After then, the specimen case 30 is hung at the hanging ring 43 thereof by means of the crane 67, and the crane 67 is moved to transport the specimen case 30 to the reduced pressure impregnating station A shown in FIG. 3. Subsequently, the specimen case 30 is lowered until it is fitted into the recess 64a of the support table 64 to place the specimen case 30 on the table 64. In this instance, the vacuum discharging port 65 provided on the table 64 is inserted into the gas discharging opening 36 of the specimen case 30 to move the valve body 37a of the valve 37 upwardly against the urging force of the spring 37b to establish communication between the port 65 and the inside of the specimen case 30.
Then, the bell-shaped furnace 61 is hung at the hanging ring 66 thereof by the crane 67 and moved down until it is placed on the table 64 to cover the entire specimen case 30 with the bell-shaped furnace 61. Then, the air in the inside of the specimen case 30 is discharged by way of the port 65 by means of the vacuum pump 60, and then, while the inside of the specimen case 30 is maintained in the reduced pressure condition, the heater 62 of the bell-shaped furnace 61 is rendered operative to heat the solid impregnant 9 in the inside of the specimen case 30 to a temperature of about 200° to 300° C. to put the impregnant 9 into a condition of molten liquid. In this instance, since the shaped body 8 is prevented from floating up by the holding member 40, it is maintained in a dipped condition in the impregnant 9. Accordingly, since tar pitch or the like of the impregnant 9 surrounds the entire shaped body 8, a vacuum impregnating processing is performed to some degree.
After then, the bell-shaped furnace 61 is lifted and removed by the crane 67, whereafter the crane 67 is used again to hang the specimen case 30 at the hanging ring 43 and move the same to the pressurizing impregnating and carbonizing station B. At the station B, the specimen case 30 is placed onto the lower inner lid 55 on the transport bogie 57 at its retracted position (indicated in broken lines in FIG. 3). Subsequently, the transport bogie 57 is moved to the location just below the high pressure vessel 50 while carrying the specimen case 30 thereon. The lifting device 59 then lifts the lower inner lid 55 on the transport bogie 57 together with the specimen case 30 until the specimen case 30 is inserted into the high pressure vessel 50 and the lower inner lid 55 is fitted in an airtight relationship into the lower outer lid 54.
Then, the press frame 56 is moved on the rail 56a to the location at which the high pressure vessel 50 is disposed, and the press frame 56 is fitted with the upper lid 53 and the lower inner lid 55 of the high pressure vessel 50. Consequently, the upper lid 53, lower inner lid 55 and lower outer lid 54 of the high pressure vessel 50 are secured to the high pressure tube 52 in a locked condition by the press frame 56. Accordingly, the various components of the high pressure vessel 50 maintain the enclosed spacing of the high pressure vessel 50 even if the internal pressure of the same is increased to a high pressure level.
After then, the air in the inside of the high pressure vessel 50 is discharged to reach a vacuum condition by a suitable vacuum pump (not shown), and then argon gas of a high pressure is introduced into the inside of the high pressure vessel 50 from a suitable high pressure argon gas supply source to replace the gas within the high pressure vessel 50 with argon gas. When the inside of the high pressure vessel 50 is filled with such high pressure argon gas until a predetermined difference is caused between the internal pressure and the external pressure of the high pressure vessel 50, the gas admitting valve 35 is opened so that the argon gas of a high pressure is admitted also into the specimen case 30. Consequently, the pressure of the gas acts directly upon a free surface of the molten impregnant 9 such as tar pitch, and accordingly, impregnation of the shaped body 8 by such high pressure gas is accomplished.
Subsequently, the heater 70 is rendered operative to raise the temperature of the contents of the specimen case 30, and the pressure is further raised by introduction of pressurized argon gas. In this instance, the temperature rise is carried out gradually in order that generation of gas by sudden carbonization of the impregnant 9 such as tar pitch may be prevented. After the temperature is raised to a predetermined level (for example, 600° to 1,500° C., the temperature is maintained while a predetermined pressure is also maintained in order to achieve carbonizing baking under the high pressure.
Preferably the pressure upon such carbonizing baking is higher than 70 kgf/cm 2 . FIG. 4 shows a relationship between a pressure and a yield of carbon, and in FIG. 4, the axis of abscissa indicates a pressure while the axis of ordinate indicates a yield of carbon. As apparently seen from FIG. 4, where the pressure applied exceeds 70 kgf/cm 2 , the yield of carbon presents a sudden increase to a high value above 80%. On the higher side of the pressure than 70 kgf/cm 2 , however, the effect of the improvement in yield of carbon by an increase in pressure is low. Accordingly, it is industrially suitable to set the pressure upon carbonizing baking to a value lower than 300 kgf/cm 2 with which the operation can be performed only with a pressure of gas from a high pressure gas bomb.
After completion of such carbonizing processing, the valve 68a is opened to permit argon gas to be discharged by way of the gas port 68 and the gas discharging opening 36 to lower the internal pressure of the specimen case 30. Then, after the temperature of the specimen case 30 is lowered to 300° C. or so but not waiting until the specimen case 30 is cooled to a room temperature, the specimen case 30 is removed from the high pressure vessel 50. After then, another new specimen case in which molten impregnant 9 is contained is set in position into the high pressure vessel 50 in a similar manner as described above, and a carbonizing processing is thereafter performed for the new specimen case.
It is to be noted that, in order to promote the carbonizing reaction described hereinabove, it is a preferable method for reduction of steps to insert a hydrogen occluding material in advance in the specimen case 30. Such hydrogen occluding material promotes a reaction of CH 4 →C+2H 2 . Consequently, the carbonizing reaction is promoted.
Further, while in the embodiment described above the bell-shaped furnace 61 is used for heating impregnant such as tar pitch into a molten condition as shown in FIG. 3, such a modified structure may be employed that the heating device 69 installed in the inside of the high pressure vessel 50 can be removed in an integral relationship with the lower outer lid 54 and lower inner lid 55 to the outside of the high pressure vessel 50 so that the specimen case 30 may be heated outside the high pressure vessel 50 using the heating device 69 to melt the impregnant such as tar pitch.
In the following, a result of an impregnating carbonizing processing which was actually performed using the apparatus of the embodiment described above will be described.
A shaped body containing 30% in volume of carbon fiber of the PAN family and about 20% in volume of carbon (and having a porosity of about 48%) and a solid block of tar pitch were set in position into such a specimen case as shown in FIG. 2, and the internal air in the specimen case was discharged outside to put the inside of the specimen case into a vacuum condition at a location outside the high pressure vessel, whereafter the specimen case was heated to a temperature of about 250° C. The specimen case was maintained at 250° C. for a period of eight hours to melt the tar pitch, and then the entire specimen case was placed into the high pressure vessel. Then, argon gas was poured into the high pressure vessel to a pressure of about 1,000 kgf/cm 2 to dip the shaped body in the molten tar pitch, whereafter the specimen case was heated to 800° C. at a rate of temperature rise of about 100° C./hour. Then, the specimen case was maintained at 800° C. for three hours to carbonize and bake the tar pitch, and then, it was cooled in the furnace gradually for two hours. Subsequently, the argon gas was discharged, and the specimen case was taken out. Then, after waiting until the specimen case was cooled to a temperature proximate the room temperature, the article thus processed was taken out of the specimen case, and the remaining carbonized tar pitch was removed. Then, the specimen was examined. As a result, it was proved that the open porosity was about 12% and sufficient impregnation and carbonization were achieved. The period of time for which the high pressure vessel was about 11 hours. Accordingly, the series of steps were processed for a period of time about one half the period of time which is required when tar pitch is melted in the high pressure vessel.
Having now fully described the invention, it will be apparent to one of ordinary skill in the art that many changes and modifications can be made thereto without departing from the spirit and scope of the invention as set forth herein. | An impregnating carbonizing process and apparatus which permit reduction in cost of consumable goods and can operate at a reduced cost and a heating and vacuum impregnating operation which requires a very long period of time can be performed on the outside of an expensive high pressure vessel to accomplish rapid carbonization and baking. The process comprises of inserting a porous shaped body of carbon and a block of impregnant into a specimen case, discharging gas from within the specimen case, heating the impregnant into a molten condition under a reduced pressure to dip the shaped body of carbon in the molten liquid of the impregnant, inserting the speciment case into a high pressure vessel, admitting high pressure gas into the high pressure vessel and also into the specimen case so as to penetrate the impregnant into the shaped body of carbon, heating the shaped body to a high temperature, and discharging the high pressure gas to lower the pressure within the specimen case at a controlled rate in response to a pressure within the high pressure vessel to carbonize the impregnant. The apparatus is constructed to suitably carry out the process. | 2 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to a method and apparatus for TLB (Translation Lookaside Buffer) invalidation mechanism for protective page fault in a X86 system. The invention particularly relates to a method and apparatus which applies a modification mechanism to invalidate the TLB entry of a protective fault page with only one-time TLB table walk.
2. Description of the Prior Art
A TLB (Translation Lookaside Buffer) is an on-chip cache that references the most recently used page table entries and translates linear addresses into physical addresses directly without having to access page tables and page directories from the main memory. The TLB is usually organized as an eight-set by four-way association of linear-address tags and physical-address datum, with related LRU and protection bits. When paging is enabled in the Protected mode, a processor's TLB references the most recently used page table entries. Then, the TLB translates linear addresses into physical addresses without having to access page tables and page directories from the main memory.
Page fault refers to a situation that the processor can retry (re-start). Page faults often occur during normal operation, such as when a new page must be loaded from disk into memory. When a service routine handles a fault, its return address points to the instruction that caused the fault so that the instruction can be retried. In a X86 computer architecture, when protective page fault occurs, the system has to apply protective page fault service routine to flush all the TLB entry, that is, invalidate all the TLB valid entries to ensure the correspondence between the entries of the page table and that of the TLB after modification. This approach reduces overall performance of the system significantly.
There is another approach which does not rely on protective page fault service routine to flush the TLB, but has to execute TLB table walk twice. This also reduces overall performance of the system.
Advanced operating systems which employs copy-on-write operating systems, such as Linux, usually will not make a copy for shared data. Instead, it sets the shared data of a page table as read-only mode, When a page with shared data has to be updated and is executing write instruction, page fault occurs. At this time, the operating system applies page fault service routine to make a copy of the page and then change the mode of both pages (the original page and the copy) to read/write mode. For such advanced operating systems, the two approaches for protective page fault stated above will reduce the performance of the system more apparently.
SUMMARY OF THE INVENTION
Accordingly, it is the primary object of the present invention to provide an improved method and apparatus for TLB invalidation mechanism for protective page fault to improve system performance.
Briefly described, the present invention encompasses a method for TLB invalidation mechanism for protective page fault. The steps of the inventive method include: (1) detecting the occurrence of protective page fault; (2) executing protective page fault processing mechanism; (3) invalidating the TLB entry for protective fault page; (4) executing protective page fault service routine; herein the TLB entry for the protective fault page has been invalidated; (5) returning to the address where protective page fault occurs; (6) executing TLB table walk to complete the modification for protective page fault; and step (6) executes TLB table walk only once.
The present invention which outputs an invalidate signal to invalidate the TLB entry for protective fault page further encompasses: invalidate address generator for generating an invalidate address input to TLB; TLB invalidation control device for inputting a signal which indicates protective page fault and a signal which indicates invalidate request and for outputting an invalidate control signal to TLB; and invalidating the TLB entry for protective fault page in response to the invalidate address and the invalidate control signal.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other objects and advantages of the present invention will become apparent by reference to the following description and accompanying drawings wherein:
FIG. 1 is a schematic diagram showing the mechanism for protective page fault according to the prior art.
FIG. 2 is a schematic diagram showing the mechanism for protective page fault according to another prior art.
FIG. 3 is a schematic diagram showing the TLB invalidation mechanism for protective page fault according to the present invention.
FIG. 4 is a block diagram showing the function blocks of the preferred embodiments according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows a modification mechanism for protective page fault according to the prior art. The detailed description for the execution steps are stated below:
10: protective page fault occurs;
11: protective page fault processing mechanism detects protective page fault and enables protective page fault service routine 12;
12: execute protective page fault service routine;
121: load page fault status/address register;
122: process/modify page table entities to ensure the entries of the page table be correct;
Please note that at step 121 and step 122, the TLB entry of protective fault page is valid.
123:.TLB entry are flushed and invalidated;
124: return to the address where page fault occurs;
13: execute TLB table walk;
At this time, since all the TLB, entry are invalidated, so when the system is executing TLB table walk 13, it will write the page table entry for protective page fault, processed/modified at step 122 into the TLB.
14: complete protective page fault modification.
The protective page fault processing mechanism 11 of FIG. 1 does not flush TLB entries. Instead, it relies on step 123 of protective page fault service routine 12 to flush TLB. This approach will invalidate all the TLB entries even though most TLB entries are correct and not have to execute TLB table walk. Therefore, it will reduce system performance significantly.
FIG. 2 shows another approach according to the prior art. The detailed description for the execution steps are described below:
20: protective page fault occurs;
21: execute TLB table walk 21 which writes the entry of a page table into TLB.
However, since the entry of the page table have not been modified yet, so the data just written in the TLB is still incorrect;
22: execute protective page fault processing mechanism;
23: execute protective page fault service routine;
231: load page fault status/address register;
232: process/modify page table entities to ensure the entries of the page table be correct;
233: return;
24: return to the address where page fault occurs;
However, at this time, page fault in the TLB still exists and fault page is still valid. Thus, protective page fault occurs again. Step 21 executes TLB table walk once more which writes page table entities modified at step 232 into the TLB. Now protective page fault processing mechanism at step 22 detects no page fault, so it does not go to step 27. Instead, it goes to step 25.
26: complete the modification of protective page fault,
FIG. 3 is a schematic diagram showing the TLB invalidation mechanism for protective page fault according to the present invention. The detailed description for the execution steps are described as follows:
30: protective page fault occurs;
31: execute protective page fault processing mechanism; protective page fault processing mechanism 31 has two functions: one is detecting the occurrence of protective page fault; the other is invalidating the TLB entry of protective fault page which is different from prior arts.
32: execute protective page fault service routine;
321: load page fault status/address register;
322: process/modify page table entities, that is, modify page table entries for fault page;
323: return;
33: return to the address where page fault occurred;
34: execute TLB table walk;
At this time, since the TLB entry for protective fault page has been invalidated before the execution of protective page fault service routine 32 and the steps that follows, including step 321, 322, and 323, therefore TLB table walk 34 is executed. The entry of page table which has been modified at step 322 is written to TLB, and validate the TLB entry of protective fault page.
35: complete the modification of protective page fault.
The main difference between FIG. 1 and FIG. 3 is that FIG. 3 does not need to flush TLB at step 123 which may invalidate TLB entry of protective fault page and then cause the occurrence of protective fault page. Furthermore, flushing TLB at step 123 also stops other correct and valid pages from being continuously used. They have to stay idle until next time when TLB table walk is executed. As mentioned above, this approach is very inefficient and will reduce system performance very significantly. In contrast, according to FIG. 3, the invention only invalidates TLB entry of protective fault page, not all the entries.
The main difference between FIG. 2 and FIG. 3 is that whenever protective page fault occurs, FIG. 2 has to execute TLB table walk twice to modify protective page fault. In contrast, the invention only needs to execute TLB table walk once to complete the modification of protective page fault.
FIG. 4 shows the function blocks according to the present invention. Invalidate address generator 40 consists of invalidate linear address 401, page fault address register 402 and MUX 403. TLB 41 consists of TAG's CAM (Content Addressable Memory) 411 and DATA's RAM 412. In addition, there is a TLB invalidation control device 44. All these devices constitute the TLB invalidation mechanism for protective page fault according to the invention.
Please refer to FIG. 4, Invalidate linear address 401 is a system invalidation request sent from the system. Page fault address register 402 stores page fault address. The inputs of MUX 403 are invalidate linear address 401 and page fault address from page fault address register 402 . The output of MUX 403 is invalidate address 404 which is delivered to TAG's CAM 411 of TLB 41. TLB invalidation control device 44 receives two signal inputs: one indicating protective page fault 42 and the other indicating invalidate request 43. TLB invalidation control device 44 outputs an invalidate control signal 45 to TAG's CAM 411 of TLB 41. Since invalidate address 404 and invalidate control signal 45 are sent to TAG's CAM 411 to set V=0, therefore the valid entries indicated by the page fault address 413 are invalidated. DATA's RAM 412 then writes correct page table into page base 414 during TLB table walk according to page base 414 indicated by page fault address 413. DATA's RAM 412 sets V=1 to validate the valid entries of page fault address 413. Thus, the invalidation mechanism for protective page fault is finished.
The primary advantage of the invention is that it contains the TLB invalidation mechanism for protective page fault in the protective page fault processing mechanism. Thus, as soon as protective page fault process is finished, modified page table entries can be correctly loaded into the TLB automatically during TLB table walk without having to use software routines to flush TLB.
Another advantage of the invention is that it is flexible and can improve system performance. The invention can be implemented in hardware or micro code according to the structure of FIG. 4.
It should be understood that various alternatives to the structures described herein may be employed in practicing the present invention. It is intended that the following claims define the invention and that the structure within the scope of these claims and their equivalents be covered thereby. | A method and apparatus for modifying protective page fault, which executes TLB table walk when protective page fault occurs in order to modify protective page fault. The method includes the following steps: (1) detecting the occurrence of protective page fault; (2) executing protective page fault processing mechanism; (3) executing protective page fault service routine; (4) returning to the address where protective page fault occurs; (5) executing TLB table walk to complete modification for protective page fault; and invalidating the TLB entry for protective fault page at step (2). | 6 |
FIELD OF THE INVENTION
This invention relates to the field of motor control systems, more particularly to phase-locked color wheel systems.
BACKGROUND OF THE INVENTION
Display systems are commonly used to convey information to system observers. Display systems typically include some type of spatial light modulator, such as a Cathode Ray Tube (CRT) or Liquid Crystal Display (LCD) to form a modulated light image. One new type of display system, which has the capability to replace the conventional Cathode Ray Tube (CRT) based display system in many applications, is based on Texas Instruments' Digital Micromirror Device (DMD). The DMD is an integrated circuit that includes a large number of very small mirrors on the surface of the circuit. A typical DMD may have over one million mirrors, each approximately 17 μm across, in a sealed package having a transparent cover over the mirrors. Addressing circuitry in the DMD is used to electrostatically rotate each mirror +/-10° about a hinge axis. The rotated position of the mirror determines the direction incident light will be deflected from the surface of the mirror.
In a typical DMD-based display system, a projection lamp generates a beam of light which is focused onto the surface of the DMD. The incident beam of light generally strikes the surface of the DMD along a path which is 20° from normal to the surface of the DMD. Mirrors which are rotated to a first "on" position reflect the incident light along a path which is normal to the surface of the DMD. Mirrors which are rotated in the opposite "off" direction, reflect light along a path which is 40° from normal to the surface of the DMD and 60° away from the incident light beam.
A projection lens is used to capture the light which has been reflected by the DMD along a path normal to the surface of the DMD. The projection lens focuses this light onto a viewing screen. Each mirror has a one-to-one relationship with a portion of the viewing screen such that for each mirror that is rotated to the "on" position, there is a corresponding bright spot on the viewing screen. The bright spots collectively form an image which may be interpreted by a viewer.
Realistic images require many intensity levels to represent realistically life-like shading and contouring. However, modern versions of the DMD are only designed to operate in either the on position, in which all of the light incident on the mirror is reflected onto the viewing screen, or in the off position, in which none of the incident light is reflected onto the viewing screen. Therefore, time based integration methods are used to create images which have multiple intensity levels. Typical video signals are transmitted as a series of video frames, or images, each frame representing the complete image at a given point in time. Time based integration is implemented by breaking each image frame into a series of subframes. Individually, each subframe is a single-intensity version of the desired image and does not represent the entire image accurately. But, because the human eye integrates a series of instantaneous images, a series of subframes may be created which will appear, to the human eye, to be a single image with multiple intensity levels.
Multiple beams of colored light are used to generate a full-color image. For example, the output of three separate image display systems, one with a red light source, one with a green light source, and one with a blue light source, may be combined to create a full-color image. Alternatively, a single image display system sequentially may use three light sources to generate a full-color image. Once again, the integration properties of the human eye are relied upon to blend the three monochromatic images of a color-serial display system into a single full-color image.
SUMMARY OF THE INVENTION
In accordance with the present invention, a motor control system is provided which provides a low-cost method of phase-locking a motor to an input timing signal. According to one embodiment of the present invention, a timer circuit measures the period of a timing signal and the relative phase between the timing signal and a motor rotor. A frequency command generator circuit outputs a motor speed command based on the period of the timing signal and the relative phase of the timing signal compared to the motor rotor. The motor speed command controls the output of a motor driver circuit such that the motor driver circuit drives the motor rotor speed synchronously with the input timing signal. The motor speed command also causes the motor driver to gradually alter the rotor speed thereby adjusting the relative phase between the input timing signal and the motor rotor. The frequency command generator introduces a small frequency-lock error in order to change the phase relationship between the rotor and the timing signal.
BRIEF DESCRIPTION OF THE DRAWINGS
For a more complete understanding of the present invention, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, in which:
FIG. 1 is a diagram of a projection display system.
FIG. 2 is a view of a color wheel of one embodiment of the projection display system in FIG. 1.
FIG. 3 is a timeline showing the time periods during which the color wheel of FIG. 2 generates each color.
FIG. 4 is a block diagram of one embodiment of a motor control circuit of the projection display system in FIG. 1.
FIG. 5 is a block diagram one embodiment of a microcontroller of the motor control circuit in FIG. 4.
FIG. 6 is a block diagram of one embodiment of a filter shown in FIG. 5.
FIG. 7 is a flowchart detailing the operation of one embodiment of the VSYNC filter in FIG. 6.
FIG. 8 is a plot of the phase command function showing the relationship between input phase error and the output phase command which is used by the motor driver to correct the phase error.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
An efficient method of generating three single-color images, shown in FIG. 1, is to use a single display system with a color wheel 102 added in the light path. In FIG. 1, light from a light source 104 passes through the color wheel 102 and is focused on a spatial light modulator 106. The spatial light modulator 106 modulates the light to form an image bearing light beam which is projected onto a viewing surface 108. A controller 110 writes image data to the spatial light modulator 106 and synchronizes the operation of the spatial light modulator 106 with the rotation of the color wheel 102.
The color wheel 102, shown in FIG. 2, is typically a transparent disk on which three different colored light filters are attached. The three light filters preferably abut on the wheel in order to maximize the amount of time the light passing through the color wheel is monochromatic. As the color wheel turns in the light path, the light passing through the wheel will be change from one color to the next. If the speed of the color wheel equals the rate at which the image frames are provided, each of the filters rotates through the light path during each frame, and each image frame is comprised of several monochromatic images. As described in U.S. Pat. No. 5,339,116, titled "DMD Architecture And Timing For Use In A Pulse-Width Modulated Display System," issued Jan. 11, 1994, each of the monochromatic image frames is comprised of multiple bit-planes, allowing the image perceived by the human eye to include a full range of colors and intensities.
The color wheel 102 shown in FIG. 2 includes red 202, green 204, and blue 206 filters, each covering one-third of the color wheel surface. The red filter is comprised of two segments while the green and blue filters are a single segment. The rotation of the color wheel is synchronized with the video frames so that each frame of video data is displayed during a period that begins and ends when the light beam is passing through the middle of the blue filter. Many other color filter combinations are possible. For example, a color wheel 102 may be fabricated with six segments, or any other number of segments. Additionally, a four-segment color wheel could have two blue segments or two green segments instead of the two red segments shown in FIG. 2.
A simplified timeline showing the periods in which the three colors are displayed is shown in FIG. 3. The bit sequences shown in FIG. 3 are for instructional purposes only and do not represent the optimum bit sequences. To avoid artifacts, the display period for some of the longer image bits is typically broken up into multiple non-contiguous display periods. Additionally, in horizontal split reset DMD systems, separate portions of the spatial light modulator will display the image bits in a unique order
A frequency-locked loop circuit may be used to synchronize the operation of the spatial light modulator and the motor used to turn the color wheel. In a frequency-locked system, motor speed is synchronized to the vertical synchronization signal, VSYNC, component of the input video signal, which indicates the beginning of each image frame. An image frame buffer stores one image frame until the color wheel reaches a point where a given filter enters the light path signalling that a new display frame is to begin. Typically, a position sensor outputs a signal, INDEX, indicating the beginning of a new display frame. After the INDEX signal is received, the display system reads the image data from the frame memory and writes it to the spatial light modulator.
A frequency-locked control circuit has the advantage of being simple to design, but requires an additional frame memory, which drives up the cost of the display, in order to buffer the output of the image processing circuitry prior to input to the spatial light modulator. Furthermore, because control systems always have some uncorrected errors, a frequency-locked loop will have some frequency error implying that the buffer/frame memory will be over/under filled. This error may cause the display system to skip a frame of data and lead to visible temporal artifacts in the projected image.
The additional frame memory may be eliminated by phase-locking the color wheel to the incoming video signal. When the color wheel is phase-locked to the input video signal, there is a pre-determined relationship between the VSYNC and INDEX signals. A phase-locked display system allows the image processing circuitry to write one frame of image data into a frame memory while the prior frame of image data is read out of a second frame memory by the spatial light modulator.
A phase-locked color wheel driver circuit presents several problems. First, the circuitry required to phase-lock the wheel to the incoming video signal is more expensive and complex than the circuitry required to merely frequency-lock that wheel to the incoming video signal. Second, if the display system is switched between input signals, such as occurs when the channel received by a television system is changed, or if the input signal is temporarily lost, the controller will lose phase-lock and must then phase-lock to the new VSYNC signal. Users of the image display systems are not willing to wait long periods while the color wheel is re-synchronized to the new VSYNC signal. In order to phase-lock to the new VSYNC signal rapidly, the motor driving the color wheel must have enough output torque to change the velocity of the color wheel abruptly. Because the cost of the color wheel motor rises with output torque, the output torque of the color wheel motor must be carefully balanced to minimize the cost of motor while still providing acceptable performance.
A similar problem is encountered when designing a display system that is capable of displaying video sequences from sources which have different frame rates. For example, European television is typically broadcast at 50 frames per second, while North American television systems broadcast video signals at a 60 frame per second rate. Video images that are generated by computer systems are often displayed at 72 frames per second. Because of the abrupt changes in color wheel velocity necessary to change quickly between different frame rates, the cost of the color wheel motor tends to increase on systems that are capable of displaying images at more than one frame rate.
One solution is based on the realization that a frequency-locked loop is a phase-locked loop with an arbitrary phase relationship between the input signal and the output signal. This realization allows the use of a simple and cost-effective frequency-locked motor controller to drive the color wheel motor, with the addition of a controller to introduce a frequency error signal which will drive the color wheel from an arbitrary position to the desired position without requiring a rapid change in the velocity of the color wheel.
First Embodiment
A first embodiment of a phase-locked motor controller, as discussed above for use in a single-modulator sequential-color display system, is shown in FIG. 4. In FIG. 4, a three-phase DC motor 402, such as a Nidec model 32S8754010, is used to turn a four to six-inch color wheel.
A three-phase brushless DC motor controller/driver 404, such as the Allegro A8902CLBA, is used to drive the motor 402 at a constant frequency. In this embodiment, the motor driver 404 receives a 14-bit period word that represents the desired period of one revolution of the motor. The period word is loaded into a 14-bit internal counter which is decremented every 16 input clock cycles. The controller generates a reference waveform which stays active until the counter reaches zero. The length of the reference waveform represents the time required for one revolution of the motor 402 at the desired speed.
The driver 404 also generates a signal, TACH, which represents the actual period of time required for one revolution of the motor 402. In this embodiment, the controller generates the TACH signal by sensing the back-EMF zero crossings of the motor 402, and dividing by 24 (3 phases times 8 poles). However, in other embodiments an external position indicator may be used. In the present embodiment, the state of the TACH signal changes with each revolution of the motor.
On alternate revolutions of the motor 402, the driver 404 compares the period of the TACH signal to the period of the reference signal. Depending on which signal ends first, a charge pump internal to the driver 404 integrates either up or down to control the current provided to the motor 402, thereby enabling the driver 404 to alter the speed of the motor 402.
Microcontroller 406 converts the circuit from a simple frequency-locked loop controller to an inexpensive phase-locked control circuit by modifying the 14-bit period word which is written into the driver 404. Microcontroller 406 monitors a color wheel position signal, INDEX, which strobes active when the color wheel rotates to a particular point. For example, INDEX may strobe active when the border between the red and blue filters crosses the light path. By measuring the VSYNC period and the relationship between the VSYNC and INDEX signals, the controller 406 determines the phase of the color wheel relative to the VSYNC signal.
The controller 406 alters the phase of the color wheel by temporarily increasing or decreasing the period word written to the driver 404. Slight changes in the period word cause the driver 404 to increase or decrease the speed of the motor 402 by a very small amount. If the actual color wheel position lags the desired color wheel position, as determined by the phase measurement between the VSYNC and INDEX signals, the speed of the motor is slightly increased until the color wheel advances to the proper phase relationship with VSYNC.
Television broadcasts in the United States have a field rate of about 60 Hz. Therefore the color wheel should nominally spin at 3600 rpm, or complete one revolution every 16.67 mS. If a 10 MHz clock is used to clock the driver 404, the 14-bit period counter is decremented at a 625 kHz rate, and the period word is nominally 10,417 which equates to a motor speed of 3,599.88 rpm.
As discussed above, it is important to limit the velocity profile of the color wheel motor. This not only reduces the cost of the motor required to spin the color wheel, but also reduces the overshoot and undershoot that will occur as the motor driver 404 attempts to change the speed of the motor. In a first embodiment, the phase loop adjustment range of the color wheel period is limited to +/-51.2 μS. The narrow range of wheel velocities (+/-0.18 rps) reduces the torque load on the motor 402 while allowing a worst-case phase error of 180° to be corrected within 5 seconds. For the nominal motor speed of 60 rpm discussed above, the controller 406 may increase the motor speed to a maximum of 3611 rpm, or decrease the motor speed to a minimum of 3589 rpm while still maintaining the velocity profile. These minimum and maximum speeds require the controller 406 to change the period word by +/-32.
Operation of the Microcontroller
FIG. 5 is a block diagram of the operation of the microcontroller 406. Blocks 502 and 504 measure the periods of the VSYNC and INDEX signals. Block 506 measures the relative timing of VSYNC and INDEX to determine the amount of lead or lag between VSYNC and INDEX. The VSYNC period is scaled and filtered by blocks 508 and 510 to determine the desired motor speed. The output from block 510, which represents the desired motor speed is input to block 512 and used to determine the desired phase offset between VSYNC and INDEX. This phase offset is subtracted from the measured phase difference to generate the phase error. Block 518 processes the phase error to get the phase error command. Block 514 receives information from blocks 502, 504, and 512, as well as the VSYNC and INDEX signals, and determines the state of several status bits. The status bits, output by block 516, include bits to indicate the state of the VSYNC and INDEX signals, a bit to indicate that the color wheel is spinning at an acceptable speed, and several bits which indicate the current frequency-lock and phase-lock status of the system.
As discussed above, the VSYNC period is both scaled and filtered to determine the desired motor speed. A scale factor of 1 is used when the VSYNC signal has a frequency between 49 and 62.9 Hz. The unitary scale factor results in a motor speed equal to the video frame rate. If the frame rate increases to more than 62.9 Hz, the motor control circuit switches into a spoke-synchronous mode, which will be discussed below, and a scale factor of 1.2 is used. If the frame rate then drops below 62.6 Hz, the motor control circuit switches out of spoke-synchronous mode and the scale factor returns to 1.
The scaled and filtered VSYNC period from block 510 and the phase error command signal from block 518 are added by adder 526 to create the 14-bit reference period word which is output by block 520 to the motor driver circuit 404. Block 528 generates a sequence start command to the display electronics using INDEX for color display modes, or TACH for black and white display modes.
Spoke-Synchronous Mode
As the color wheel is turned faster, more power is required by the motor 402 and the time period each filter is in the light path is reduced. As the time period for each filter is reduced, it becomes more difficult to load and reset the modulator with each bit plane. Even when split-reset methods are used, fast frame rates may require reducing the number of bit planes displayed, or the use of blanking periods during which mirrors temporarily are turned off to allow the addressing circuitry beneath the mirrors to be loaded. Blanking periods lower the optical efficiency of the display system resulting in a reduced-brightness display.
Spoke-synchronous mode, which is described in U.S. Pat. application Ser. No. 08/659,485, entitled "Sequential Color Display System with Spoke Synchronous Frame Rate Conversion," filed on Jun. 6, 1996 and hereby incorporated by reference, is used to limit the velocity range over which the motor must operate, thereby increasing the efficiency of the display system. In spoke-synchronous mode, the color wheel is only turned 300° every VSYNC, or frame period, which results in the relationship between VSYNC and the color wheel changing 60° each frame period. Because the color wheel does not rotate an entire revolution each frame period, the proportion of time a given color filter is in the light path will not be equal for each color, and the color balance of the displayed image will be adversely affected. However, over a period of several frames, each of the three colors will be affected equally and a viewer will not notice that the color balance of each frame is incorrect.
VSYNC Filter
A VSYNC filter, which is described more fully in U.S. Pat. application Ser. No. 08/662,803, entitled "Tracking Filter," filed on Jun. 12, 1996 and hereby incorporated by reference, acts to smooth the measured period of the VSYNC signal. The filter incorporates both a first order response and a second order response to allow the smoothed VSYNC period to quickly respond to large changes in the input VSYNC period, which occur on a change in input source frame rates, while minimizing the response of the motor to spurious jumps in the VSYNC period, which may occur when a change in the input source causes a change in the VSYNC phase. A conventional second order filter designed to rapidly respond to changes in the input signal has a much larger overshoot.
A block diagram of the filter is shown in FIG. 6. As shown in FIG. 6, the smoothed VSYNC period signal output by the filter is subtracted from the input VSYNC period to determine the VSYNC error. Error signal generation block 602 creates two error signals based on the VSYNC error. The first error signal, for use in the first order loop, is the VSYNC error divided by 16, plus one. The first error signal is limited to the range of +/-8 LSB. The second error signal, for use in the second order loop, is the VSYNC error limited to the range of +/-1 LSB.
The second error signal is integrated by accumulator 604 each VSYNC period. The accumulator controller 606 limits the range of the accumulator 604 between +127 and -128 LSBs. The accumulator controller also clears the accumulator 604 whenever the signs of the accumulator 604 and the second error signal disagree.
The integrated second error signal from the accumulator 604 is divided by four and added to the first error signal and the previous value of the smoothed VSYNC period to create a new smoothed VSYNC period value. A flowchart detailing the operation of the VSYNC filter is shown in FIG. 7.
Phase Error Generation
The temporal relationship between the INDEX and VSYNC signals is used to determine the phase offset of the color wheel and to generate a phase error signal. One embodiment using the color wheel of FIG. 2 receives VSYNC as the motor rotates past the mid-point of the blue filter, and generates an INDEX signal at the red-blue boundary of the color wheel through the light path. This embodiment results in a desired phase offset, VSYNC to INDEX, of 300°. Of course, the relationship between INDEX, VSYNC, and the color wheel position is arbitrary.
The phase error signal represents the difference between the actual VSYNC to INDEX phase delay, and the desired phase offset. The microcontroller 406 calculates the actual phase delay by subtracting the VSYNC time-of-arrival from the INDEX time-of-arrival. The microcontroller 406 then subtracts the desired phase offset from the value of the actual phase delay, leaving the phase error value.
In spoke-synchronous mode, the desired phase offset varies for each frame of video data. Recall that in spoke-synchronous mode, the color wheel only rotates 300° during each frame of video data. Therefore, the desired phase offset must change each frame. In spoke-synchronous mode, the phase offset word continually follows the sequence, 300°, 240°, 180°, 120°, 60°, 0°.
Phase Commands
As shown by block 518 of FIG. 5, after the microcontroller 406 calculates the phase error, it translates the phase error into a phase command which is added to the VSYNC period word, and output to the motor driver 404. The magnitude of the phase command varies depending on the phase error, and is chosen to avoid phase tracking instability and overshoot. A graph of a typical phase command function 802 is shown in FIG. 8. In FIG. 8, the phase command function 802 is shown as a series of steps, each tending to drive the phase error toward zero. When the phase error is very small, the phase command is zero. As the phase error increases, the phase commands increase to quickly reduce the phase error to zero. In FIG. 8, the phase command function is linear and the step size doubles each step. Many other functions could be used to generate the phase commands including simply scaling the phase error, or scaling the phase error and limiting the magnitude of the phase command.
Sequence Codes
As the speed of the color wheel changes, the amount of time available to display an image during each revolution also changes. The speed of the color wheel will change whenever the input video signal changes frame rates. Also, changing video sources typically changes the speed of the color wheel as the system attempts to lock the phase of the color wheel to the new video signal. When the display system is in spoke-synchronous mode, the controller may step to a new phase offset to minimize the initial phase error and expedite the phase-lock process.
If the spatial light modulator is driven so that each image frame is the same length, a short frame display length must be chosen to avoid running over into the following color wheel frame period when the color wheel is spinning too quickly. Choosing a frame display period that is short enough to avoid problems when the color wheel is spinning too quickly reduces the efficiency of the display system when the color wheel is spinning at the proper speed because the spatial light modulator will not operate during the last portion of the color wheel frame period. Additionally, if a constant frame display length is too short, the spatial light modulator may begin to display a color plane while the color wheel is still filtering the light using the previous color filter.
To maximize the efficiency of the display system while avoiding color artifacts, the microcontroller 406 generates a sequence code, based on the color wheel period, which is used by the display system to control the length of the frame display period. As shown in FIG. 5, block 522 uses the measured index period to generate a sequence code which is output by block 524. In a first embodiment, 43 6-bit codes are used to communicate the length of the frame display period as determined by the actual color wheel speed.
The sequence codes are used to alter the bit display periods when there is a significant error in the color wheel frequency. For example, if the display system is changed from a 60 Hz frame rate signal to a 72 Hz frame rate signal, the system will enter spoke-synchronous mode and the color wheel will be rotating too fast for the new signal. Because the color wheel is rotating too fast, the image data bit periods for each color must be shortened in order to finish the video frame before the color wheel rotates 300°. The display period of a frame may be shortened by either shortening the bit periods, only displaying some of the bits, or both. In a first embodiment, 43 6-bit sequence codes are used to coordinate the color wheel with the rest of the display system.
Although the present invention has been discussed in terms of a color wheel motor controller, the novel features of this invention may be used in other fields, such as a motor controller for a video read/write head. Furthermore, although the present invention has been discussed with reference to a first embodiment having a integrated circuit motor controller and a microcontroller, the motor controller could be implemented using many other combinations of circuits including discrete logic gates or analog circuitry.
Thus, although there has been disclosed to this point a particular embodiment for a phase-lock motor control circuit and method therefore, it is not intended that such specific references be considered as limitations upon the scope of this invention except insofar as set forth in the following claims. Furthermore, having described the invention in connection with certain specific embodiments thereof, it is to be understood that further modifications may now suggest themselves to those skilled in the art, it is intended to cover all such modifications as fall within the scope of the appended claims. | A motor control system provides a low-cost method of phase-locking a motor to an input timing signal. Timer circuits 502, 506 measure the period of a timing signal and the relative phase between the timing signal and a motor rotor. A frequency command generator circuit 520 outputs a motor speed command based on the period of the timing signal and the relative phase of the timing signal compared to the motor rotor. The motor speed command controls the output of a motor driver circuit which drives the motor rotor speed synchronously with the input timing signal. The rotor speed is gradually altered to adjust the relative phase between the input timing signal and the motor rotor. This results in a small frequency-lock error being used to maintain a predetermined phase relationship between the timing signal and the motor rotor. | 7 |
FIELD OF THE INVENTION
[0001] This invention relates generally to deuterium-enriched fenofibrate, pharmaceutical compositions containing the same, and methods of using the same.
BACKGROUND OF THE INVENTION
[0002] Fenofibrate, shown below, is a well known drug of the fibrate class.
[0000]
[0000] Since fenofibrate is a known and useful pharmaceutical, it is desirable to discover novel derivatives thereof. Fenofibrate is described in U.S. Pat. Nos. 4,058,552 the contents of which are incorporated herein by reference.
SUMMARY OF THE INVENTION
[0003] Accordingly, one object of the present invention is to provide deuterium-enriched fenofibrate or a pharmaceutically acceptable salt thereof.
[0004] It is another object of the present invention to provide pharmaceutical compositions comprising a pharmaceutically acceptable carrier and a therapeutically effective amount of at least one of the deuterium-enriched compounds of the present invention or a pharmaceutically acceptable salt thereof.
[0005] It is another object of the present invention to provide a method for treating hypercholesterolemia, hypertriglyceridemia, and cardiovascular disease, comprising administering to a host in need of such treatment a therapeutically effective amount of at least one of the deuterium-enriched compounds of the present invention or a pharmaceutically acceptable salt thereof.
[0006] It is another object of the present invention to provide a novel deuterium-enriched fenofibrate or a pharmaceutically acceptable salt thereof for use in therapy.
[0007] It is another object of the present invention to provide the use of a novel deuterium-enriched fenofibrate or a pharmaceutically acceptable salt thereof for the manufacture of a medicament (e.g., for the treatment of hypercholesterolemia, hypertriglyceridemia, and cardiovascular disease).
[0008] These and other objects, which will become apparent during the following detailed description, have been achieved by the inventor's discovery of the presently claimed deuterium-enriched fenofibrate.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0009] Deuterium (D or 2 H) is a stable, non-radioactive isotope of hydrogen and has an atomic weight of 2.0144. Hydrogen naturally occurs as a mixture of the isotopes 1 H (hydrogen or protium), D ( 2 H or deuterium), and T ( 3 H or tritium). The natural abundance of deuterium is 0.015%. One of ordinary skill in the art recognizes that in all chemical compounds with a H atom, the H atom actually represents a mixture of H and D, with about 0.015% being D. Thus, compounds with a level of deuterium that has been enriched to be greater than its natural abundance of 0.015%, should be considered unnatural and, as a result, novel over their non-enriched counterparts.
[0010] All percentages given for the amount of deuterium present are mole percentages.
[0011] It can be quite difficult in the laboratory to achieve 100% deuteration at any one site of a lab scale amount of compound (e.g., milligram or greater). When 100% deuteration is recited or a deuterium atom is specifically shown in a structure, it is assumed that a small percentage of hydrogen may still be present. Deuterium-enriched can be achieved by either exchanging protons with deuterium or by synthesizing the molecule with enriched starting materials.
[0012] The present invention provides deuterium-enriched fenofibrate or a pharmaceutically acceptable salt thereof There are twenty-one hydrogen atoms in the fenofibrate portion of fenofibrate as show by variables R 1 -R 21 in formula I below.
[0000]
[0013] The hydrogens present on fenofibrate have different capacities for exchange with deuterium. The hydrogen atoms of fenofibrate are not easily exchangeable and may be incorporated by the use of deuterated starting materials or intermediates during the construction of fenofibrate.
[0014] The present invention is based on increasing the amount of deuterium present in fenofibrate above its natural abundance. This increasing is called enrichment or deuterium-enrichment. If not specifically noted, the percentage of enrichment refers to the percentage of deuterium present in the compound, mixture of compounds, or composition. Examples of the amount of enrichment include from about 0.5, 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, 12, 16, 21, 25, 29, 33, 37, 42, 46, 50, 54, 58, 63, 67, 71, 75, 79, 84, 88, 92, 96, to about 100 mol %. Since there are 21 hydrogens in fenofibrate, replacement of a single hydrogen atom with deuterium would result in a molecule with about 5% deuterium enrichment. In order to achieve enrichment less than about 5%, but above the natural abundance, only partial deuteration of one site is required. Thus, less than about 5% enrichment would still refer to deuterium-enriched fenofibrate.
[0015] With the natural abundance of deuterium being 0.015%, one would expect that for approximately every 6,667 molecules of fenofibrate (1/0.00015=6,667), there is one naturally occurring molecule with one deuterium present. Since fenofibrate has 21 positions, one would roughly expect that for approximately every 140,007 molecules of fenofibrate (21×6,667), all 21 different, naturally occurring, mono-deuterated fenofibrates would be present. This approximation is a rough estimate as it doesn't take into account the different exchange rates of the hydrogen atoms on fenofibrate. For naturally occurring molecules with more than one deuterium, the numbers become vastly larger. In view of this natural abundance, the present invention, in an embodiment, relates to an amount of an deuterium enriched compound, whereby the enrichment recited will be more than naturally occurring deuterated molecules.
[0016] In view of the natural abundance of deuterium-enriched fenofibrate, the present invention also relates to isolated or purified deuterium-enriched fenofibrate. The isolated or purified deuterium-enriched fenofibrate is a group of molecules whose deuterium levels are above the naturally occurring levels (e.g., 5%). The isolated or purified deuterium-enriched fenofibrate can be obtained by techniques known to those of skill in the art (e.g., see the syntheses described below).
[0017] The present invention also relates to compositions comprising deuterium-enriched fenofibrate. The compositions require the presence of deuterium-enriched fenofibrate which is greater than its natural abundance. For example, the compositions of the present invention can comprise (a) a μg of a deuterium-enriched fenofibrate; (b) a mg of a deuterium-enriched fenofibrate; and, (c) a gram of a deuterium-enriched fenofibrate.
[0018] In an embodiment, the present invention provides an amount of a novel deuterium-enriched fenofibrate.
[0019] Examples of amounts include, but are not limited to (a) at least 0.01, 0.02, 0.03, 0.04, 0.05, 0.1, 0.2, 0.3, 0.4, 0.5, to 1 mole, (b) at least 0.1 moles, and (c) at least 1 mole of the compound. The present amounts also cover lab-scale (e.g., gram scale), kilo-lab scale (e.g., kilogram scale), and industrial or commercial scale (e.g., multi-kilogram or above scale) quantities as these will be more useful in the actual manufacture of a pharmaceutical. Industrial/commercial scale refers to the amount of product that would be produced in a batch that was designed for clinical testing, formulation, sale/distribution to the public, etc.
[0020] In another embodiment, the present invention provides a novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof.
[0000]
[0021] wherein R 1 -R 21 are independently selected from H and D; and the abundance of deuterium in R 1 -R 21 is at least 5%. The abundance can also be (a) at least 10%, (b) at least 14%, (c) at least 19%, (d) at least 24%, (e) at least 29%, (f) at least 33%, (g) at least 38%, (h) at least 43%, (i) at least 48%, (j) at least 52%, (k) at least 57%, (l) at least 62%, (m) at least 67%, (n) at least 71%, (o) at least 76%, (p) at least 81%, (q) at least 86%, (r) at least 90%, (s) at least 95%, and (t) 100%.
[0022] In another embodiment, the present invention provides a novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 1 -R 7 is at least 14%. The abundance can also be (a) at least 29%, (b) at least 43%, (c) at least 57%, (d) at least 71%, (e) at least 86%, and (f) 100%.
[0023] In another embodiment, the present invention provides a novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 8 -R 13 is at least 17%. The abundance can also be (a) at least 33%, (b) at least 50%, (c) at least 67%, (d) at least 83%, and (e) 100%.
[0024] In another embodiment, the present invention provides a novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 14 -R 17 is at least 25%. The abundance can also be (a) at least 50%, (b) at least 75%, and (c) 100%.
[0025] In another embodiment, the present invention provides a novel, deuterium enriched compound of formula I, wherein the abundance of deuterium in R 18 -R 21 is at least 25%. The abundance can also be (a) at least 50%, (b) at least 75%, and (c) 100%.
[0026] In another embodiment, the present invention provides a novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 1 -R 13 is at least 8%. The abundance can also be (a) at least 15%, (b) at least 23%, (c) at least 31%,(d) at least 38%, (e) at least 46%, (f) at least 54%, (g) at least 62%, (h) at least 69%, (i) at least 77%, (j) at least 85%, (k) at least 92%, and (l) 100%.
[0027] In another embodiment, the present invention provides a novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 1 -R 7 and R 14 -R 17 is at least 9%. The abundance can also be (a) at least 18%, (b) at least 27%, (c) at least 36%, (d) at least 45%, (e) at least 56%, (f) at least 64%, (g) at least 73%, (h) at least 82%, (i) at least 91%, and (j) 100%.
[0028] In another embodiment, the present invention provides a novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 1 -R 7 and R 18 -R 21 is at least 9%. The abundance can also be (a) at least 18%, (b) at least 27%, (c) at least 36%, (d) at least 45%, (e) at least 56%, (f) at least 64%, (g) at least 73%, (h) at least 82%, (i) at least 91%, and (j) 100%.
[0029] In another embodiment, the present invention provides a novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 8 -R 17 is at least 10%. The abundance can also be (a) at least 20%, (b) at least 30%, (c) at least 40%, (d) at least 50%, (e) at least 60%, (f) at least 70%, (g) at least 80%, (h) at least 90%, and (i) 100%.
[0030] In another embodiment, the present invention provides a novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 8 -R 13 and R 18 -R 21 is at least 10%. The abundance can also be (a) at least 20%, (b) at least 30%, (c) at least 40%, (d) at least 50%, (e) at least 60%, (f) at least 70%, (g) at least 80%, (h) at least 90%, and (i) 100%.
[0031] In another embodiment, the present invention provides a novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 1 -R 17 is at least 6%. The abundance can also be (a) at least 12%, (b) at least 18%, (c) at least 24%, (d) at least 29%, (e) at least 35%, (f) at least 41%, (g) at least 47%, (h) at least 53%, (i) at least 59%, (j) at least 65%, (k) at least 71%, (l) at least 76%, (m) at least 82%, (n) at least 88%, (o) at least 94%, and (p) 100%.
[0032] In another embodiment, the present invention provides a novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 1 -R 13 and R 18 -R 21 is at least 6%. The abundance can also be (a) at least 12%, (b) at least 18%, (c) at least 24%, (d) at least 29%, (e) at least 35%, (f) at least 41%, (g) at least 47%, (h) at least 53%, (i) at least 59%, (j) at least 65%, (k) at least 71%, (l) at least 76%, (m) at least 82%, (n) at least 88%, (o) at least 94%, and (p) 100%.
[0033] In another embodiment, the present invention provides a novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 1 -R 7 and R 14 -R 21 is at least 7%. The abundance can also be (a) at least 13%, (b) at least 20%, (c) at least 27%, (d) at least 33%, (e) at least 40%, (f) at least 47%, (g) at least 53%, (h) at least 60%, (i) at least 67%, (j) at least 73%, (k) at least 80%, (l) at least 87%, (m) at least 93%, and (n) 100%.
[0034] In another embodiment, the present invention provides a novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 8 -R 21 is at least 7%. The abundance can also be (a) at least 14%, (b) at least 21%, (c) at least 29%, (d) at least 36%, (e) at least 43%, (f) at least 50%, (g) at least 57%, (h) at least 64%, (i) at least 71%, (j) at least 79%, (k) at least 86%, (l) at least 93%, and (m) 100%.
[0035] In another embodiment, the present invention provides an isolated novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof.
[0000]
[0036] wherein R 1 -R 21 are independently selected from H and D; and the abundance of deuterium in R 1 -R 21 is at least 5%. The abundance can also be (a) at least 10%, (b) at least 14%, (c) at least 19%, (d) at least 24%, (e) at least 29%, (f) at least 33%, (g) at least 38%, (h) at least 43%, (i) at least 48%, (j) at least 52%, (k) at least 57%, (l) at least 62%, (m) at least 67%, (n) at least 71%, (o) at least 76%, (p) at least 81%, (q) at least 86%, (r) at least 90%, (s) at least 95%, and (t) 100%.
[0037] In another embodiment, the present invention provides an isolated novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 1 -R 7 is at least 14%. The abundance can also be (a) at least 29%, (b) at least 43%, (c) at least 57%, (d) at least 71%, (e) at least 86%, and (f) 100%.
[0038] In another embodiment, the present invention provides an isolated novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 8 -R 13 is at least 17%. The abundance can also be (a) at least 33%, (b) at least 50%, (c) at least 67%, (d) at least 83%, and (e) 100%.
[0039] In another embodiment, the present invention provides an isolated novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 14 -R 17 is at least 25%. The abundance can also be (a) at least 50%, (b) at least 75%, and (c) 100%.
[0040] In another embodiment, the present invention provides an isolated novel, deuterium enriched compound of formula I, wherein the abundance of deuterium in R 18 -R 21 is at least 25%. The abundance can also be (a) at least 50%, (b) at least 75%, and (c) 100%.
[0041] In another embodiment, the present invention provides an isolated novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 1 -R 13 is at least 8%. The abundance can also be (a) at least 15%, (b) at least 23%, (c) at least 31%,(d) at least 38%, (e) at least 46%, (f) at least 54%, (g) at least 62%, (h) at least 69%, (i) at least 77%, (j) at least 85%, (k) at least 92%, and (l) 100%.
[0042] In another embodiment, the present invention provides an isolated novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 1 -R 7 and R 14 -R 17 is at least 9%. The abundance can also be (a) at least 18%, (b) at least 27%, (c) at least 36%, (d) at least 45%, (e) at least 56%, (f) at least 64%, (g) at least 73%, (h) at least 82%, (i) at least 91%, and (j) 100%.
[0043] In another embodiment, the present invention provides an isolated novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 1 -R 7 and R 18 -R 21 is at least 9%. The abundance can also be (a) at least 18%, (b) at least 27%, (c) at least 36%, (d) at least 45%, (e) at least 56%, (f) at least 64%, (g) at least 73%, (h) at least 82%, (i) at least 91%, and (j) 100%.
[0044] In another embodiment, the present invention provides an isolated novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 8 -R 17 is at least 10%. The abundance can also be (a) at least 20%, (b) at least 30%, (c) at least 40%, (d) at least 50%, (e) at least 60%, (f) at least 70%, (g) at least 80%, (h) at least 90%, and (i) 100%.
[0045] In another embodiment, the present invention provides an isolated novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 8 -R 13 and R 18 -R 21 is at least 10%. The abundance can also be (a) at least 20%, (b) at least 30%, (c) at least 40%, (d) at least 50%, (e) at least 60%, (f) at least 70%, (g) at least 80%, (h) at least 90%, and (i) 100%.
[0046] In another embodiment, the present invention provides an isolated novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 1 -R 17 is at least 6%. The abundance can also be (a) at least 12%, (b) at least 18%, (c) at least 24%, (d) at least 29%, (e) at least 35%, (f) at least 41%, (g) at least 47%, (h) at least 53%, (i) at least 59%, (j) at least 65%, (k) at least 71%, (l) at least 76%, (m) at least 82%, (n) at least 88%, (o) at least 94%, and (p) 100%.
[0047] In another embodiment, the present invention provides an isolated novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 1 -R 13 and R 18 -R 21 is at least 6%. The abundance can also be (a) at least 12%, (b) at least 18%, (c) at least 24%, (d) at least 29%, (e) at least 35%, (f) at least 41%, (g) at least 47%, (h) at least 53%, (i) at least 59%, (j) at least 65%, (k) at least 71%, (l) at least 76%, (m) at least 82%, (n) at least 88%, (o) at least 94%, and (p) 100%.
[0048] In another embodiment, the present invention provides an isolated novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 1 -R 7 and R 14 -R 21 is at least 7%. The abundance can also be (a) at least 13%, (b) at least 20%, (c) at least 27%, (d) at least 33%, (e) at least 40%, (f) at least 47%, (g) at least 53%, (h) at least 60%, (i) at least 67%, (j) at least 73%, (k) at least 80%, (l) at least 87%, (m) at least 93%, and (n) 100%.
[0049] In another embodiment, the present invention provides an isolated novel, deuterium enriched compound of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 8 -R 21 is at least 7%. The abundance can also be (a) at least 14%, (b) at least 21%, (c) at least 29%, (d) at least 36%, (e) at least 43%, (f) at least 50%, (g) at least 57%, (h) at least 64%, (i) at least 71%, (j) at least 79%, (k) at least 86%, (l) at least 93%, and (m) 100%.
[0050] In another embodiment, the present invention provides novel mixture of deuterium enriched compounds of formula I or a pharmaceutically acceptable salt thereof.
[0000]
[0051] wherein R 1 -R 21 are independently selected from H and D; and the abundance of deuterium in R 1 -R 21 is at least 5%. The abundance can also be (a) at least 10%, (b) at least 14%, (c) at least 19%, (d) at least 24%, (e) at least 29%, (f) at least 33%, (g) at least 38%, (h) at least 43%, (i) at least 48%, (j) at least 52%, (k) at least 57%, (l) at least 62%, (m) at least 67%, (n) at least 71%, (o) at least 76%, (p) at least 81%, (q) at least 86%, (r) at least 90%, (s) at least 95%, and (t) 100%.
[0052] In another embodiment, the present invention provides a novel mixture of deuterium enriched compounds of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 1 -R 7 is at least 14%. The abundance can also be (a) at least 29%, (b) at least 43%, (c) at least 57%, (d) at least 71%, (e) at least 86%, and (f) 100%.
[0053] In another embodiment, the present invention provides a novel mixture of deuterium enriched compounds of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 8 -R 13 is at least 17%. The abundance can also be (a) at least 33%, (b) at least 50%, (c) at least 67%, (d) at least 83%, and (e) 100%.
[0054] In another embodiment, the present invention provides a novel mixture of deuterium enriched compounds of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 14 -R 17 is at least 25%. The abundance can also be (a) at least 50%, (b) at least 75%, and (c) 100%.
[0055] In another embodiment, the present invention provides a novel mixture of deuterium enriched compounds of formula I, wherein the abundance of deuterium in R 18 -R 21 is at least 25%. The abundance can also be (a) at least 50%, (b) at least 75%, and (c) 100%.
[0056] In another embodiment, the present invention provides a novel mixture of deuterium enriched compounds of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 1 -R 13 is at least 8%. The abundance can also be (a) at least 15%, (b) at least 23%, (c) at least 31%,(d) at least 38%, (e) at least 46%, (f) at least 54%, (g) at least 62%, (h) at least 69%, (i) at least 77%, (j) at least 85%, (k) at least 92%, and (l) 100%.
[0057] In another embodiment, the present invention provides a novel mixture of deuterium enriched compounds of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 1 -R 7 and R 14 -R 17 is at least 9%. The abundance can also be (a) at least 18%, (b) at least 27%, (c) at least 36%, (d) at least 45%, (e) at least 56%, (f) at least 64%, (g) at least 73%, (h) at least 82%, (i) at least 91%, and (j) 100%.
[0058] In another embodiment, the present invention provides a novel mixture of deuterium enriched compounds of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 1 -R 7 and R 18 -R 21 is at least 9%. The abundance can also be (a) at least 18%, (b) at least 27%, (c) at least 36%, (d) at least 45%, (e) at least 56%, (f) at least 64%, (g) at least 73%, (h) at least 82%, (i) at least 91%, and (j) 100%.
[0059] In another embodiment, the present invention provides a novel mixture of deuterium enriched compounds of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 8 -R 17 is at least 10%. The abundance can also be (a) at least 20%, (b) at least 30%, (c) at least 40%, (d) at least 50%, (e) at least 60%, (f) at least 70%, (g) at least 80%, (h) at least 90%, and (i) 100%.
[0060] In another embodiment, the present invention provides a novel mixture of deuterium enriched compounds of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 8 -R 13 and R 18 -R 21 is at least 10%. The abundance can also be (a) at least 20%, (b) at least 30%, (c) at least 40%, (d) at least 50%, (e) at least 60%, (f) at least 70%, (g) at least 80%, (h) at least 90%, and (i) 100%.
[0061] In another embodiment, the present invention provides a novel mixture of deuterium enriched compounds of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 1 -R 17 is at least 6%. The abundance can also be (a) at least 12%, (b) at least 18%, (c) at least 24%, (d) at least 29%, (e) at least 35%, (f) at least 41%, (g) at least 47%, (h) at least 53%, (i) at least 59%, (j) at least 65%, (k) at least 71%, (l) at least 76%, (m) at least 82%, (n) at least 88%, (o) at least 94%, and (p) 100%.
[0062] In another embodiment, the present invention provides a novel mixture of deuterium enriched compounds of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 1 -R 13 and R 18 -R 21 is at least 6%. The abundance can also be (a) at least 12%, (b) at least 18%, (c) at least 24%, (d) at least 29%, (e) at least 35%, (f) at least 41%, (g) at least 47%, (h) at least 53%, (i) at least 59%, (j) at least 65%, (k) at least 71%, (l) at least 76%, (m) at least 82%, (n) at least 88%, (o) at least 94%, and (p) 100%.
[0063] In another embodiment, the present invention provides a novel mixture of deuterium enriched compounds of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 1 -R 7 and R 14 -R 21 is at least 7%. The abundance can also be (a) at least 13%, (b) at least 20%, (c) at least 27%, (d) at least 33%, (e) at least 40%, (f) at least 47%, (g) at least 53%, (h) at least 60%, (i) at least 67%, (j) at least 73%, (k) at least 80%, (l) at least 87%, (m) at least 93%, and (n) 100%.
[0064] In another embodiment, the present invention provides a novel mixture of deuterium enriched compounds of formula I or a pharmaceutically acceptable salt thereof, wherein the abundance of deuterium in R 8 -R 21 is at least 7%. The abundance can also be (a) at least 14%, (b) at least 21%, (c) at least 29%, (d) at least 36%, (e) at least 43%, (f) at least 50%, (g) at least 57%, (h) at least 64%, (i) at least 71%, (j) at least 79%, (k) at least 86%, (l) at least 93%, and (m) 100%.
[0065] In another embodiment, the present invention provides novel pharmaceutical compositions, comprising: a pharmaceutically acceptable carrier and a therapeutically effective amount of a deuterium-enriched compound of the present invention.
[0066] In another embodiment, the present invention provides a novel method for treating a disease selected from hypercholesterolemia, hypertriglyceridemia, and cardiovascular disease comprising: administering to a patient in need thereof a therapeutically effective amount of a deuterium-enriched compound of the present invention.
[0067] In another embodiment, the present invention provides an amount of a deuterium-enriched compound of the present invention as described above for use in therapy.
[0068] In another embodiment, the present invention provides the use of an amount of a deuterium-enriched compound of the present invention for the manufacture of a medicament (e.g., for the treatment of hypercholesterolemia, hypertriglyceridemia, and cardiovascular disease).
[0069] The present invention may be embodied in other specific forms without departing from the spirit or essential attributes thereof. This invention encompasses all combinations of preferred aspects of the invention noted herein. It is understood that any and all embodiments of the present invention may be taken in conjunction with any other embodiment or embodiments to describe additional more preferred embodiments. It is also to be understood that each individual element of the preferred embodiments is intended to be taken individually as its own independent preferred embodiment. Furthermore, any element of an embodiment is meant to be combined with any and all other elements from any embodiment to describe an additional embodiment.
Definitions
[0070] The examples provided in the definitions present in this application are non-inclusive unless otherwise stated. They include but are not limited to the recited examples.
[0071] The compounds of the present invention may have asymmetric centers. Compounds of the present invention containing an asymmetrically substituted atom may be isolated in optically active or racemic forms. It is well known in the art how to prepare optically active forms, such as by resolution of racemic forms or by synthesis from optically active starting materials. All processes used to prepare compounds of the present invention and intermediates made therein are considered to be part of the present invention. All tautomers of shown or described compounds are also considered to be part of the present invention.
[0072] “Host” preferably refers to a human. It also includes other mammals including the equine, porcine, bovine, feline, and canine families.
[0073] “Treating” or “treatment” covers the treatment of a disease-state in a mammal, and includes: (a) preventing the disease-state from occurring in a mammal, in particular, when such mammal is predisposed to the disease-state but has not yet been diagnosed as having it; (b) inhibiting the disease-state, e.g., arresting it development; and/or (c) relieving the disease-state, e.g., causing regression of the disease state until a desired endpoint is reached. Treating also includes the amelioration of a symptom of a disease (e.g., lessen the pain or discomfort), wherein such amelioration may or may not be directly affecting the disease (e.g., cause, transmission, expression, etc.).
[0074] “Therapeutically effective amount” includes an amount of a compound of the present invention that is effective when administered alone or in combination to treat the desired condition or disorder. “Therapeutically effective amount” includes an amount of the combination of compounds claimed that is effective to treat the desired condition or disorder. The combination of compounds is preferably a synergistic combination. Synergy, as described, for example, by Chou and Talalay, Adv. Enzyme Regul. 1984, 22:27-55, occurs when the effect of the compounds when administered in combination is greater than the additive effect of the compounds when administered alone as a single agent. In general, a synergistic effect is most clearly demonstrated at sub-optimal concentrations of the compounds. Synergy can be in terms of lower cytotoxicity, increased antiviral effect, or some other beneficial effect of the combination compared with the individual components.
[0075] “Pharmaceutically acceptable salts” refer to derivatives of the disclosed compounds wherein the parent compound is modified by making acid or base salts thereof. Examples of pharmaceutically acceptable salts include, but are not limited to, mineral or organic acid salts of the basic residues. The pharmaceutically acceptable salts include the conventional quaternary ammonium salts of the parent compound formed, for example, from non-toxic inorganic or organic acids. For example, such conventional non-toxic salts include, but are not limited to, those derived from inorganic and organic acids selected from 1,2-ethanedisulfonic, 2-acetoxybenzoic, 2-hydroxyethanesulfonic, acetic, ascorbic, benzenesulfonic, benzoic, bicarbonic, carbonic, citric, edetic, ethane disulfonic, ethane sulfonic, fumaric, glucoheptonic, gluconic, glutamic, glycolic, glycollyarsanilic, hexylresorcinic, hydrabamic, hydrobromic, hydrochloric, hydroiodide, hydroxymaleic, hydroxynaphthoic, isethionic, lactic, lactobionic, lauryl sulfonic, maleic, malic, mandelic, methanesulfonic, napsylic, nitric, oxalic, pamoic, pantothenic, phenylacetic, phosphoric, polygalacturonic, propionic, salicyclic, stearic, subacetic, succinic, sulfamic, sulfanilic, sulfuric, tannic, tartaric, and toluenesulfonic.
Synthesis
[0076] Scheme 1 shows a route to fenofibrate. A Friedel-Crafts reaction of 1 and 2 is one of many ways to synthesize the benzophenone 3. For this particular method, see Inada, et al., JP 04082858 ( Chem. Abstr. 117:89962). Conversion of 3 to 4 and 5 is reported in Mieville, US 4058552.
[0000]
[0077] Scheme 2 shows how various deuterated starting materials and intermediates can be used in the chemistry of Scheme 1 to make deuterated fenofibrate analogs. A person skilled in the art of organic synthesis will recognize that these materials may be used in various combinations to access a variety of other deuterated fenofibrates. Equation (1) shows how deuterated acetone and deuterated chloroform may be used to prepare 6 (see Scheme 1 for analogous protio chemistry). If 6 is used in place of 4 in the chemistry of Scheme 1, fenofibrate with R 8 -R 13 =D results. Various deuterated forms of chlorobenzene are commercially available (7 and 9) or known (8). If 7 is used in place of 1 in the chemistry of Scheme 1, fenofibrate with R 18 -R 21 =D results. If 8 is used in place of 1 in the chemistry of Scheme 1, fenofibrate with R 20 -R 21 =D results. If 9 is used in place of 1 in the chemistry of Scheme 1, fenofibrate with R 18 -R 19 =D results. The tetradeuterated 4-hydroxybenzoic acid 10 is commercially available, and the two dideuterio forms 11 and 12 are known. If 10 is used in place of 2 in the chemistry of Scheme 1, fenofibrate with R 14 -R 17 =D results. If 11 is used in place of 2 in the chemistry of Scheme 1, fenofibrate with R 14 -R 15 =D results. If 12 is used in place of 2 in the chemistry of Scheme 1, fenofibrate with R 16 -R 17 =D results. The deuterated forms of isopropanol 13, 14, and 15 are commercially available. If 13 is used in place of isopropanol in the chemistry of Scheme 1, fenofibrate with R 1 -R 6 =D results. If 14 is used in place of isopropanol in the chemistry of Scheme 1, fenofibrate with R 1 -R 7 =D results. If 15 is used in place of isopropanol in the chemistry of Scheme 1, fenofibrate with R 7 =D results.
[0000]
EXAMPLES
[0078] Table 1 provides compounds that are representative examples of the present invention. When one of R 1 -R 21 is present, it is selected from H or D.
[0000]
1
2
3
4
5
6
7
8
9
10
11
12
13
14
[0079] Table 2 provides compounds that are representative examples of the present invention. Where H is shown, it represents naturally abundant hydrogen.
[0000]
15
16
17
18
19
20
21
22
23
24
25
26
27
28
[0080] Numerous modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that within the scope of the appended claims, the invention may be practiced otherwise that as specifically described herein. | The present application describes deuterium-enriched fenofibrate, pharmaceutically acceptable salt forms thereof, and methods of treating using the same. | 2 |
The present invention relates to a closed circuit cooling system, that is a cooling system in which no interior part communicates directly with the outside in normal use.
Closed circuit cooling systems are well-known for removing excess heat from many different situations by means of circulating a cooling fluid between a heated body and a heat exchanger. Usually the operation of such systems includes the use of some form of temperature dependent control, usually by mechanical or electrical thermostatic device. In the case of the cooling of a compact heat source or heated body it is known to pass a cooling fluid around or through the heat source. To provide for rapid heating to a preset desired operating temperature the fluid is not passed to a heat exchanger until the temperature of the fluid rises towards or reaches a value which ensures optimum operating temperature. When that temperature value is reached the operation of a valve causes the fluid to be passed to the heat exchanger.
A common example of such a system is the cooling system of an internal-combustion engine in a motor vehicle, where a mechanical valve or thermostat responds directly to the temperature of the water used to cool the engine. Provision has to be made in a closed circuit cooling system to allow for the expansion of the coolant. Again considering the case of a motor vehicle it is usual to provide an expansion chamber containing air in which the liquid coolant expands such that the air becomes pressurized.
Closed circuit cooling systems are known in which the expansion chamber contains a collapsible body such as a metal bellows, which is compressed by the expanding fluid. Such systems use a separate temperature-controlled bypass valve, the thermostatic valve, to control the configuration of the closed circuit around which the cooling fluid flows.
GB 1079539 discloses a closed circuit cooling system comprising a cooling circuit connecting a heated body to a heat exchanger and including means for circulating a cooling fluid and a valve including a variable volume actuator, for bypassing the heat exchanger. The valve comprises a flexible bellows, the interior of which is connected to the cooling circuit at or near a restriction which acts as a venturi. The pressure drop in the venturi throat causes a change in the volume of the bellows and operates the valve.
It is an object of the present invention to provide a closed circuit cooling system requiring fewer components.
SUMMARY OF THE INVENTION
According to the present invention, there is provided a closed circuit cooling system comprising a cooling circuit connecting a heated body to a heat exchanger and including means for circulating a cooling fluid, a valve including a variable volume actuator being provided for bypassing the heat exchanger; characterized in that in use, changes in the volume of the cooling fluid cause the variable column actuator to change volume to actuate the valve so as to cause the fluid to bypass the heat exchanger when the temperature of the fluid is below a predetermined valve and to accommodate any changes in fluid volume due to temperature changes.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention will now be described with reference to the accompanying drawings, in which:
FIG. 1 is a schematic diagram of a cooling system according to an embodiment of the invention;
FIG. 2 is an isometric exploded view of one form of valves for use with the invention;
FIG. 3 is a sectional view of the valve of FIG. 2; and
FIG. 4 is a schematic diagram of a second embodiment of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to FIG. 1, this illustrates a closed circuit cooling system using a liquid to remove heat from a heat-producing body 10 such as a laser. The liquid is circulated by a pump 11 around the circuit which includes a heat exchanger 12. A fluid, commonly air, passes through the heat exchanger 12 and removes heat from the circulating liquid. Since the cooling system is sealed, provision has to be made for the expansion of the circulating liquid as its temperature rises. Conveniently this is done by providing an expansion chamber 13 which may consist of a flexible bellows 14 having the fluid in contact with one surface and conveniently, having the other surface exposed to ambient air pressure.
A cooling system as so far described is conventional but has certain disadvantages if the body 10 is best operated at an elevated temperature. In particular, warm-up of the body is slow since the cooling liquid is always circulating through the heat exchanger. This problem may be avoided by providing a bypass 15 for the heat exchange with a valve to close the bypass and pass the cooling liquid through the heat exchanger 12 when the temperature of the liquid rises. It is usual for a temperature-sensitive device such as a thermostat to be used for this purpose, either forming part of the valve or remotely controlling the operation of the valve. By "thermostat" is meant a device, usually mechanical or electrical, which is directly responsive to the temperature of the cooling fluid and to no other parameter of that fluid.
According to the invention the need for a thermostat is avoided. Instead, use is made of the fact that the expansion chamber 13 contains a movable member which may itself act as or operate the necessary valve. In this case, therefore, the valve is operated in changes in the volume of the cooling fluid at its temperature changes and not due to the temperature of the fluid itself.
FIG. 2 is an exploded isometric view of one form of valve which may be used. The expansion chamber is formed by a cylindrical chamber 20 in a body 21. A bellows element 22 of metal or other suitable material is located inside the chamber 20 which is sealed by a bellows mounting plate 23. Three passages or ports are formed through the side of the body 21 to communicate with the chamber. These passages are be denoted by the references 24, 25 and 26.
The inside of the chamber is provided with a fixed sleeve 27, held in position by a peg 28. Sleeve 27 may be split by a slot (not shown) to enable it to be an interference fit in the chamber 20. Three apertures are formed through the sleeve 27 to allow each of the passages 24, 25 and 26 access to the chamber 20.
Attached to the bottom of the bellows 22 by a fastener such as a circlip 29 is a valve member 30. This is able to slide coaxially within the sleeve 27 and has a sealing fit inside the sleeve 27. Valve member 30 has suitably-located cut-away portions to enable it to perform the necessary valve action. Cut-away portions 32 and 33 are located opposite passages 25 and 26 respectively. If necessary the peg 28 may project into a slot 34 in valve sleeve 30 to prevent rotation of that sleeve.
FIG. 3 shows the valve in one operating position, with the bellows 22 expanded to its maximum extent. The cooling liquid is at a low temperature in this situation. Liquid flows through the passage 24 in the body 21 and through cut-away 31 in member 30 into the cavity 20. Valve member 30 is in a position in which passage 26 is closed-off and passage 25 is open, thus allowing the cooling liquid to bypass the heat exchanger 12 and return directly to the heat source 10. As the temperature of the liquid rises due to the absorption of heat from the body 10, the liquid expands. The resultant increase in volume causes the bellows 22 to become compressed, thus raising the valve member 30 from its original position. The cut-away portions 32 and 33 are shaped and located so that passage 26 opens before passage 25 closes, thus allowing continuous circulation of the cooling liquid. Expansion of the liquid beyond the level required to effect the necessary movement of the valve member 30 has no further effect on the configuration of the liquid cooling circuit.
The heat-producing body 10 may take any of a number of forms. It may be an internal-combustion engine, for example or a piece of electrical or electronic equipment. In some circumstances the body 10 may initially require heating, for example if it is used in a very low temperature environment. Only when the body generates sufficient heat need the cooling system function as described above. In such a case the liquid circuit may include a heating device and controlling thermostat as shown schematically in FIG. 4 at 40. Any suitable form of heat source 40 may be used which can be controlled by a thermostat.
In the embodiments described above the cooling fluid has been a liquid. The cooling system may use a gaseous fluid in a similar way, through the coefficient of expansion and hence the volume change with temperature will be much greater.
In certain circumstances it may not be necessary to use a pump to circulate the cooling fluid and circulation may be achieved by convection alone.
The form of valve described above is perhaps the simplest mechanical arrangement which can be operated by the expansion of the cooling fluid. Other forms of valve may be provided operated by a bellow-type expansion chamber. Alternatively, other types of expansion-compensating device such as sliding piston, flexible diaphragm or the like may be used to operate a suitable form of valve. | A cooling fluid is circulated around a closed circuit including a heat source, for example by a pump. The system includes a heat exchanger for removing heat from the fluid. Valve means are provided which are operated by changes in volume of the cooling fluid to cause the fluid to bypass the heat exchanger when the temperature of the fluid is below a predetermined value. | 5 |
TECHNICAL FIELD
[0001] The invention relates to a method of controlling the function of a work machine and more particularly to a method of controlling the raise/extend function of a telescopic material handler.
BACKGROUND
[0002] Material handling machines, such as telescopic material handlers are faced with stability problems during operation. These machines have these problems because of their high lifting capability, especially when heavy loads are being transported. These problems are even more troublesome when the material handlers are operated on work sites that have uneven terrain and are littered with debris. Many material handlers are provided with high ground clearance involving maintaining as much of the machine as possible elevated from the terrain, especially those elements which extend across the width of the vehicle, such as the axles. While high ground clearance facilitates maneuverability of the material handler it compounds the stability problem because of the elevated center of gravity. The stability problem is particularly acute when the material handlers are required to elevate substantial loads to considerable heights and move about on uneven terrain while balancing the load.
[0003] Heretofore in utilizing material handlers on or over uneven terrain or work surfaces, load spilling and machine stability have sometimes been major operational problems. Various attempts have been made to stabilize material handlers in such situations one example is disclosed in U.S. Pat. No. 3,937,339 issued Feb. 10, 1976 to Geis et al. and assigned to Koehring Company of Milwaukee, Wis. This stabilizing system uses two pair of mercury switches, mounted to the body of the machine, one of the pair being actuated at a time to select between coarse and fine adjustment settings. The system automatically, through the use of a solenoid valve, supplies pressurized fluid to a pair of cylinders to level the body of the machine during operation. This system allows for adjustments to counter act uneven terrain while traversing a work sight and during a load lifting operation. However, this system can cause a load to be dumped due to rapid adjustments, inadvertent contact with an obstacle during lifting, let alone the uneasiness in the ride felt by an operator during an adjustment while traversing a work site.
[0004] The present invention is directed to overcoming one or more of the following problems as set forth above.
SUMMARY OF THE INVENTION
[0005] In one aspect of the present invention a method for controlling a boom raise/extend function of a work machine is provided. The work machine has a longitudinal frame and a support member. The method includes sensing the pressure at both ends of at least one hydraulic cylinder positioned between the frame and the support member. Comparing the sensed force reacted by the at least one hydraulic cylinder to a desired predetermined limit and controlling the boom raise/extend in response to the sensed force being within a predetermined limit.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] [0006]FIG. 1 is a side elevation view of a work machine embodying the present invention;
[0007] [0007]FIG. 2 is a front elevation view of a work machine embodying the present invention;
[0008] [0008]FIG. 3 is a schematic diagram illustrating a portion of a hydraulic circuit of the present invention; and
[0009] [0009]FIG. 4 is a flowchart illustrating the various operational steps.
DETAILED DESCRIPTION
[0010] Referring to FIGS. 1 and 2, a work machine such as a telescopic handler 10 is shown. It will be understood that this invention is equally applicable to other work machines, such as forestry machinery and other non-construction related machinery. In general, the work machine 10 comprises a frame 12 , and a telescopic boom 14 that is pivotally mounted to the rear of the frame 12 for elevation to various angles relative to the frame 12 . The telescopic boom 12 is extended and retracted by a hydraulic cylinder (not shown) and is raised and lowered by cylinders 15 (only one shown in FIG. 1). In addition, an operator cab 16 is provided on one side of the frame 12 , and an engine enclosure 18 is provided opposite the boom 14 , so that the boom 14 , when lowered, extends between the cab 14 and the engine enclosure 18 .
[0011] Front and rear support members such as axles 20 , 22 are pivotally mounted on the frame 12 for oscillating motion about a pivot point 24 parallel to the center-line of the frame 12 . The axles 20 , 22 carry front and rear wheels 26 of equal size, steered by means of hydraulic cylinders in a known manner. At least one hydraulic cylinder 28 is pivotally connected between the frame 12 and the front axle 20 and used to level the frame 12 relative to the ground, one cylinder may be used on either side of pivot point 24 may be used as well, when the machine 10 is operating on uneven terrain. As an alternative, some work machines include a support member 21 attached to the frame 12 . As shown in phantom in FIG. 2, support member 21 is an outrigger arrangement that includes a pair of legs 23 that are each controlled by cylinders 27 . Graphically represented on the cab 14 in FIGS. 1 and 2 is an electronic control module 30 . A first inclinometer 32 is shown attached to the cab 16 in FIG. 2 and a second inclinometer 34 is attached to the telescopic boom 15 in FIG. 1. Both inclinometers 32 , 34 are connected to the electronic control module 30 as by wire and receive signals therefrom related to the angular position of the frame 12 and the boom 15 respectively.
[0012] Referring now to FIG. 3 a portion of a lateral stabilization circuit 36 is shown. Lateral stabilization circuit 36 includes a supply conduit 38 that connects a source of pressurized fluid (not shown) to a control valve 40 . A return conduit 42 drains the pressurized fluid back from the control valve 40 to a reservoir (not shown). Control valve 40 is a three position, four-way solenoid valve of any of a number of given configurations that is connected to hydraulic cylinder 28 via a conduit 44 and a conduit 46 . It should be understood that at least one of hydraulic cylinders 27 may be used in the representative circuit as an alternative without departing from the gist of this disclosure. Positioned in each of the conduits 44 , 46 is a counter balance valve 48 . In this example the counter balance valve 48 is used as a safety device that includes a pilot input 50 and a relief setting arrangement 52 . The counter balance valve 48 positioned in conduit 46 includes a pilot line 54 connecting the pilot input 50 to conduit 44 , while the counter balance valve 48 positioned in conduit 44 includes a pilot line 54 connecting the pilot input 50 to conduit 46 . A check valve 56 is positioned in parallel to each of the counter balance valves 48 so that fluid flow from the cylinder 28 is blocked. Additionally, connected to conduits 44 , 46 between the counter balance valves 48 and the control valve 40 is a resolver 58 that drains to a signal line 60 . Signal line 60 sends a fluid signal representative of load to a controller (not shown) such as a pump controller as is commonly known.
[0013] Referring now to FIG. 4 a method for controlling the lateral stability of work machine 10 is illustrated. The controller 30 receives signals from various operator inputs such as a joystick, control lever or similar input device (not shown) requesting a desired raise/extend operation of the telescopic boom 14 and from the first and second inclinometers 32 , 34 . A calculation block 62 compares the actual position of the frame 12 and the telescopic boom 14 and compares the angular readings from the inclinometers 32 , 34 to stored data such as maps look up tables and the like in decision block 64 . If the frame 12 is within a predetermined limit or the raise/extend request does not put the work machine 10 in an unstable position a control block 66 of the controller 30 allows signals from the operator controls (not shown) providing full functionality of the telescopic boom 14 . Additionally, the level function is locked at this point in a control block 68 . If the frame 12 is not within the predetermined limit the controller 30 compares the frame 12 position and the telescopic boom 14 position signals from inclinometers 32 , 34 respectively, in a decision block 70 to see if any movement of the telescopic boom 14 will place the machine in an unstable position. If the frame 12 is not within the predetermined limit and any raise/extend request places the work machine 10 in an unstable position, from block 70 , a control block 72 of the controller 30 disables operator controls for raise/extend function. However, lower/retract functionality is still provided. At this point the operators options are provided in a control block 74 and allow the operator to send a signal through an operator input (not shown) to request the controller 30 to send a signal to control valve 34 to shift, allowing pressurized fluid to flow to either hydraulic cylinder 28 or at least one of hydraulic cylinders 27 to provide an automatic leveling function. If the frame 12 is not within the predetermined limit and a raise/extend request will not place the work machine 10 in an unstable position (i.e. the extend/raise is within a predetermined range) in block 70 , a control block 76 always operator control to provide limited raise/extend function until the controller 30 receives signals from inclinometer 34 representative of an unstable position, the controller 30 then disables operator controls for raise/extend function in control block 72 .
Industrial Applicability
[0014] In operation a raise/extend input command is provided to controller 30 from the operator to raise/extend the telescopic boom 14 . To raise/extend the telescopic boom 14 , the controller 30 receives signals from the first and second inclinometers 32 , 34 . The controller 30 compares these signals to stored data related to the lateral orientation of the work machine 10 and position of the telescopic boom 14 in calculation block 62 . The controller 30 then makes a determination of the work machine being in an unstable position in decision block 64 . If the work machine 10 is found to be in a safe lateral orientation control block 66 allows for a load to be raised/extended (i.e. the cylinders 15 to raise telescopic boom 14 or the cylinder to extend telescopic boom 14 ) and the level function is blocked out in control block 68 . The controller 30 determines if a raise/extend request will place the work machine 10 in an unsafe position in decision block 70 . If the work machine 10 is not in a safe lateral orientation control block 72 disables the load raise/extend capability of the work machine 10 . Control block 74 then allows the operator to maneuver the frame 12 by supplying a command to the hydraulic cylinder 27 , 28 to laterally position the work machine 10 in a safe position so that a load can be raised/extended. Or the operator can lower/retract the telescopic boom 14 and reposition the work machine 10 in a laterally stable position. If a raise/extend request will not place the work machine 10 in an un-safe lateral orientation control block 76 allows a limited amount of raise/extend capability of the work machine 10 until just before an un-safe condition then control block 72 disables the load raise/extend capability of the work machine 10 . Control block 74 then allows the operator to maneuver the frame 12 by supplying a command to the hydraulic cylinder 27 , 28 to laterally position the work machine 10 in a safe position so that a load can be raised/extended.
[0015] In view of the foregoing it is readily apparent that the method provides a process for controlling the raise/extend function of a work machine 10 . The method is for the most part automatic but does allow operator intervention so as to level the frame 12 of the machine 10 relative to the horizontal so as not to put the load or machine in an unstable situation. | A method for controlling the raise/extend function of a work machine is provided. The method comprises sensing the position of a frame and the position of a telescopic boom of the work machine, comparing the sensed positions to a desired position and controlling the raise/extend operation in response to the actual verses the desired positions. | 4 |
BACKGROUND OF THE INVENTION
The invention relates to intermediates useful in the preparation of 6-fluoro-7-halo-quinolonecarboxylic acid intermediates for the preparation of 6-fluoro-7-substituted-quinolonecarboxylic acids having antibacterial activity, and to processes for the preparation of such intermediates.
In general, the antibacterial 6-fluoro-7-substituted-quinolone-carboxylic acids are prepared by substitution of the corresponding 7-halo-6-fluoroquinolonecarboxylic acid intermediates wherein the halo atom is preferably fluoro or chloro. Prior art methods for preparing such 7-halo intermediates are described in U.S. Pat. Nos. 4,563,459 and 4,623,650.
SUMMARY OF THE INVENTION
The present invention relates to a novel process for the preparation of 7-halo-quinolonecarboxylic acid intermediates of the formula ##STR1## wherein R 3 is ethyl, t-butyl, cyclopropyl, phenyl, 4-fluorophenyl, or 2,4-difluorophenyl, R 4 is hydroxy, C 1 -C 4 alkoxy, amino or C 1 -C 4 alkylamino, and X is fluoro or chloro, and novel intermediates useful therein.
One class of intermediates of the invention are novel compounds of the formula ##STR2## wherein R 1 is hydrogen or C 1 -C 4 alkyl, R 2 is iodo, t-butylamino, cyclopropylamino, phenylamino, 4-fluorophenylamino, or 2,4-difluorophenylamino, and X is fluoro or chloro, with the proviso that when R 2 is iodo R 1 is hydrogen. Preferred intermediates within this class are compounds of formula V wherein R 1 is hydrogen, X is fluoro, and R 2 is iodo, cyclopropylamine, or 2,4-difluorophenyl.
Another class of intermediates of the invention are novel compounds of the formula ##STR3## wherein X and R 3 are as defined above with reference to formula I.
According to the invention, compounds of the formula I are prepared by reacting a compound of the formula ##STR4## wherein R 3 and X are as defined above, with an alkali metal salt of a compound of the formula
HOCH=CH--COR.sub.4
wherein R 4 is as defined above with reference to formula I.
The compounds of formula II are prepared, according to the invention, by reacting a compound of the formula ##STR5## wherein X and R 3 are as defined above with a compound of the formula
R.sub.5 R.sub.6 C=O
wherein R 5 and R 6 are both chloro or trichloromethyloxy, or R 5 is chloro and R 6 is C 1 -C 6 alkoxy, trichloromethyloxy, phenoxy, or phenoxy substituted by a substituent which is inert under the reaction conditions such as one, two or three of halo, nitro, C 1 -C 6 alkyl, or trifluoromethyl. Preferably, R 5 and R 6 are both trichloromethoxy, or both chloro, or R 5 is chloro and R 6 is trichloromethyloxy.
The compounds of formula III are prepared, according to the invention, by reacting a compound of the formula ##STR6## wherein X is fluoro or chloro, and Hal is iodo, bromo or chloro, with a compound of the formula R 3 NH 2 wherein R 3 is ethyl, t-butyl, cyclopropyl, phenyl, 4-fluorophenyl, or 2,4-difluorophenyl, in the presence of copper or a copper compound.
The overall reaction to prepare compounds of formula I from compounds of formula IV through the above intermediate process steps for the preparation of compounds of formulas II and III, is also part of the invention.
DETAILED DESCRIPTION OF THE INVENTION
The compounds of formula IV wherein Hal is iodo are novel compounds. They may be prepared from the known compound 2-amino-4,5-difluoro benzoic acid by reaction with sodium nitrite in a solution of dilute sulfuric acid at a temperature of about -10° to 0° C. and ambient pressure. The formed diazonium compound is then treated with a solution of potassium iodide in dilute sulfuric acid at a temperature between about -10° to 0° C., and the resulting dark slurry stirred for about 12 to 24 hours on slow warming to ambient temperature.
The preparation of anthranilic acid compounds of the formula III from compounds of the formula IV proceeds in the presence of catalytic amounts of copper (0) or a copper compound such as cupric oxide or cuprous oxide, or a copper salt such as cupric acetate, cupric sulfate, cupric chloride, cupric bromide, cupric triflate, cuprous chloride, cuprous bromide, and cuprous triflate. The copper catalyst is generally present in amounts of at least about 5 mole %, and generally about 10 to 20 mole %. The reaction is in the presence of an inert, dipolar, aprotic solvent such as dimethylformamide, tetrahydrofurane, dimethoxyethane, N-methyl-pyrrolidinone, dimethyl acetamide or dimethyl sulfoxide, and in the presence of an organic base such as pyridine or dimethylaminopyridine in the optional presence of a tertiary amine base such as triethyl amine or diisopropylethyl amine. The organic base is generally present in amounts of 1 to 2 mole equivalents, usually 1.5 mole equivalent.
The reaction temperature depends on whether Hal in formula IV is iodo, bromo or chloro. When Hal is iodo, the reaction may be conducted at about 10° to 40° C., and advantageously at ambient temperature such as about 20° to 25° C. When Hal is bromo, the reaction temperature is from about 20° to 50° C. When Hal is chloro, the reaction temperature is about 50° to about 100° C., generally about 70° C., and the reaction is conducted in a sealed vessel causing a reaction pressure of between one atmosphere to about two atmospheres.
When Hal in formula IV is iodo or chloro, the reaction is at least initially in the absence of air, for instance by introduction of an inert gas such as nitrogen into the reaction vessel, or by conducting the reaction in a sealed vessel.
It was found that high yields are obtained by using about two mole equivalents of the reagent of the formula R 3 NH 2 , about 1.5 mole equivalents of the organic base pyridine in dimethyl formamide, and about 0.2 mole equivalent of the copper catalyst.
The reaction may also be conducted with one equivalent of R 3 NH 2 , one equivalent of copper or its salts and 1.5 equivalent pyridine in dimethyl formamide.
The isatoic anhydrides of formula II are prepared from compounds of formula III by reaction with a reagent of the formula R 5 R 6 C═O wherein R 5 and R 6 are as defined above. For instance, the reagent is phosgene or, preferably, bis-(trichloromethyl)carbonate (triphosgene) which is commercially available and, as a solid, is easy to handle. When the above reagent is a solid, the reaction is conducted in an inert solvent such as a chlorinated alkane, e.g. methylene chloride, chloroform, carbon tetrachloride or dichloroethane, or an aromatic solvent such as toluene, benzene, or xylene. The reaction is conducted at about -10° to 15° C. for about 15 minutes to 1.5 hours, usually for half an hour. When the reagent is phosgene, the solvent may also be an aqueous acid such as hydrochloric acid. When the reagent is a liquid such as methyl chloroformate or ethyl chloroformate, the solvent may be omitted and an excess of the reagent may be used instead. The reaction mixture is then heated between about 150° and 200° C. for about 18 to 24 hours.
The reaction to form the isatoic anhydrides of formula II is performed in the presence of an organic base such as pyridine or dimethylaminopyridine in the optional presence of a tertiary amine such as triethyl amine or diisopropylethylamine.
The quinolones of formula I are prepared from the isatoic anhydrides II by reaction with at least about one equivalent of the alkali metal salt of C 1 -C 3 -alkyl 3-hydroxyacrylate. The alkali metal is sodium, lithium or potassium. The reaction is conducted in a dipolar aprotic solvent such as dimethylformamide, tetrahydrofurane, dimethoxyethane, N-methylpyrrolidinone, or dimethylacetamide. The reaction temperature ranges from about 20° to 100° C., usually about 50° C., and the reaction time is about 1 to 24 hours, usually about 1 hour. The reaction is advantageously conducted in the presence of a chelating agent for alkali metal ions. Examples of suitable chelating agents are N,N'-dimethylimidazolidinone, hexamethyl phosphoric triamide, N,N'-dimethylpropylene urea, and tris[2-(methoxyethoxy)ethyl]amine.
The quinolones of formula I wherein R 4 is hydroxy may be prepared from the corresponding esters of formula I wherein R 4 is C 1 -C 4 alkoxy by conventional hydrolysis, for instance by heating with an acid such as hydrochloric acid.
The following Examples illustrate the invention.
EXAMPLE I
To a 1 liter four neck round bottom flask equipped with mechanical stirrer, two dropping funnels and a thermometer was introduced 20 g (86.71 mmol) of 2-amino-4,5-difluorobenzoic acid and a solution of 12.3 ml concentrated sulfuric acid in 90 ml water. The slurry was cooled to between 0° and -5° C. in an ice-acetone bath. One of the dropping funnels was charged with a solution of 6.57 g (95.22 mmol) sodium nitrite in 30 ml of water and slow addition of the solution was begun. The internal reaction temperature never rose above 0° C. and all the solution has been introduced after 5 minutes. The second dropping funnel was charged with a solution of 21.6 g (128.31 mmol) potassium iodide in 45 ml of 1N sulfuric acid. This solution was then added dropwise over a period of 10 minutes with the internal temperature at or below 0° C. During addition, the reaction mixture releases nitrogen gas which causes some foaming. Once the addition was completed, the dark mixture was stirred overnight while slowly warming to room temperature. The reaction mixture was quenched with a solution of 30 g of sodium bisulfite in 165 ml water and the suspension was adjusted to pH 2.5 with 5 ml of 6 N hydrochloric acid. The resulting slurry was stirred at 0° C. for 30 minutes and then filtered. Purification of the dark material was effected by dissolving the majority of the solid in ethyl acetate followed by clarification and treatment with activated charcoal. After filtration through a filter aid (celite) and evaporation there was obtained 20 g (82%) of 2-iodo-4,5-difluorobenzoic acid; m.p.: 126°-127° C.
EXAMPLE II
To a 35 ml single neck round bottom flask equipped with magnetic stir bar and nitrogen inlet was charged 45 mg (0.704 mmol) copper bronze, 5 ml of anhydrous dimethylformamide (DMF), 430 μl (5.28 mmol) of pyridine and 537 μl (7.75 mmol) cyclopropylamine. The resulting suspension was then treated with a solution of 1 g (3.52 mmol) 2-iodo-4,5-difluorobenzoic acid in 5 ml of DMF and the mixture was stirred overnight at room temperature. The reaction mixture, now a near solution, was clarified and then added to water (100 ml) at pH 4.5. A slurry forms immediately but before filtration the mixture was once again adjusted to pH 4.5 with 6N hydrochloric acid and cooled to 0° C. Filtration of the white solid afforded 0.720 g (95%) of 2-N-cyclopropylamino-4,5-difluorobenzoic acid; m.p.: 175°-176° C.
EXAMPLE III
To a 10 ml resealable pressure reaction flask equipped with a magnetic stirrer and teflon septum cap was charged a solution of 1.0 g (5.19 mmol) 2-chloro-4,5-difluorobenzoic acid, 792 μl (11.43 mmol) cyclopropylamine, 800 mg (4.15 mmol) copper(I) iodide and 630 μl (7.79 mmol) pyridine in 8.0 ml of N,N-dimethylacetamide. The flask was sealed and was heated to 70° C. during stirring for a period of 16 hours. The reaction mixture was allowed to cool to room temperature and was then added to 100 ml of water. The suspension was adjusted to pH 13 with sodium hydroxide solution and was stirred for 15 minutes at room temperature. The suspension was filtered and the filtrate was adjusted to pH 4.5 with concentrated aqueous HCl. Filtration of the resulting slurry provided 451 mg (41%) of 2-cyclopropylamino-4,5-difluorobenzoic acid; m.p.: 175°-176° C.
EXAMPLE IV
To a 10 ml single neck round bottom flask equipped with a septum and magnetic stirring bar was charged a solution of 100 mg (0.46 mmol) of 2-N-cyclopropylamino-4,5-difluorobenzoic acid and 62μl (0.44 mmol) of triethylamine in 2 ml of methylene chloride. The solution was cooled to 0° C. and was treated with a solution of 45 mg (0.147 mmol) bis-(trichloromethyl)carbonate in 0.5 ml methylene chloride. Finally a catalytic amount of dimethylaminopyridine (10 mg) was introduced as a solution in methylene chloride (0.5 ml). After stirring at 0° C. for 1.5 hours, the reaction mixture was quenched by adding a small amount of 1N hydrochloric acid. The organic phase was dried over sodium sulfate and then concentrated to a yellow oil to afford 114 mg of N-cyclopropyl-6,7-difluoro-2H-3,1-benzoxazine-2,4(1H)dione (100%). The product was crystallized from hot ethanol; m.p.: 138°-139° C.
EXAMPLE V
To a 15 ml single neck round-bottom flask equipped with magentic stirrer and under nitrogen atmosphere was added 60 mg (0.484 mmol) of the sodium salt of methyl 3-hydroxyacrylate in 1.5 ml of DMF. The resulting solution was stirred in the presence of 4A molecular sieves overnight and then filtered into another reaction vessel fitted with condenser, nitrogen line and a magnetic stirrer. To the mixture was charged 52 μl (0.467 mmol) N,N'-dimethylimidazolidinone and the solution was heated to 55° C. To this reactor was added a solution of 93 mg (0.388 mmol) of N-cyclopropyl-6,7-difluoro-2H-3,1-benzoxazine-2,4(1H) dione in 1.5 ml of DMF. The reaction mixture was stirred at 55° C. for 1 hour. The system was allowed to cool to room temperature and was then added to 30 ml of water at pH 4.0. The pH of the resulting suspension was adjusted to 5.5 and the mixture was cooled to 0° C. and filtered. After drying there was obtained 50 mg (46%) of methyl 1-cyclopropyl-6,7-difluoro-1,4-dihydro-4-oxo-3-quinolinecarboxylate, m.p.: 223° -224° C. The filtrate was extracted with methylene chloride and after drying and evaporation there was obtained an additional 47 mg (43.5%, total yield: 89.5%) of the desired product.
EXAMPLE VI
A suspension of triethyl amine (15 ml, 0.11 mol), 2,4-difluoroaniline (25 ml, 0.24 mol), copper bronze (2.7 g., 0.04 mol), in hot DMF (25 ml) was treated with a solution of 2-chloro-4,5-difluorobenzoic acid (23 g., 0.12 mol) in 25 ml of DMF and the temperature was maintained at 85° C. for 8 hours. The reaction mixture was allowed to cool to room temperature and was then stirred overnight. The reaction mixture was evaporated in vacuo and the residue was partitioned between ether and aqueous ammonium chloride. The organic phase was washed with 2N HCl and saturated aqueous lithium chloride solution. The ether was dried over sodium sulfate, treated with darco and then filtered and evaporated. The residue was crystallized from hexane-ether to afford 21.6 g (62%) of 2-(2,4-difluorophenylamino)-4,5-difluorobenzoic acid; m.p.: 215°-216° C. | Quinolonecarboxylic acid intermediaes useful in the preparation of antibacterial 6-fluouro-7-substituted-quinolonecarboxylic acids are prepared from 2-(iodo, bromo or chloro)-3-fluoro-4-(fluoro or chloro)-phenyl carboxylic acid or ester. | 2 |
FIELD OF INVENTION
[0001] The present invention relates to a backlight control circuit. More particularly, the present invention relates to a backlight control circuit which uses a low voltage rating capacitor to provide a high output voltage.
BACKGROUND OF THE INVENTION
[0002] In a liquid crystal display, a backlight control circuit is used which controls light emitting diodes (LEDs) to illuminate from the back side of a liquid crystal screen, so that a user can observe an image from the front side of the liquid crystal screen.
[0003] In early days, LED backlight is used only in a small size screen, which does not require high backlight brightness. Therefore, the LEDs can be connected all in series or all in parallel. FIG. 1 shows a prior art circuit wherein all LEDs are connected in series. As shown in the figure, a backlight control circuit 1 comprises a backlight control integrated circuit 10 which includes an input terminal and an output terminal, wherein the input terminal is connected with an input capacitor Cin to receive an input voltage Vin, and the output terminal is connected with an output capacitor Cout to provide an output voltage Vout. (Besides the backlight control integrated circuit 10 and the two above-mentioned capacitors, other devices irrelevant to the spirit of the present invention, such as magnetic devices, are omitted for simplicity.)
[0004] The backlight control integrated circuit 10 provides output voltage Vout to a plurality of LEDs L 1 -LN connected in series, and the output voltage Vout is provided via a voltage supply circuit 11 according to a signal 15 which is outputted from an error amplifier circuit 13 . A resistor R is provided on a path of the LEDs connected in series, and a voltage at a node Vsense 1 is compared with a reference voltage Vref to check whether a current through the path satisfies a predetermined condition. If the current is lower than a predetermined value and the voltage at the node Vsense 1 decreases, the error amplifier circuit 13 sends the signal 15 to the voltage supply circuit 11 to pull up the output voltage Vout, so that the current flowing through the LEDs increases. Additionally, to avoid the voltage supply circuit 11 from unlimitedly increasing the output voltage Vout (for example, when the error amplifier circuit 13 malfunctions, or when the path of the LEDs is open), an over voltage protection circuit 12 is provided in the backlight control integrated circuit 10 , which detects the output voltage Vout and sends a signal to stop the voltage supply circuit 11 from increasing Vout if the output voltage Vout is excessively high. (Depending on circuit design, the voltage supply can be totally stopped, or kept at an upper limit value. The latter is more popular in a backlight control circuit.)
[0005] FIG. 2 shows a typical structure of an over voltage protection circuit 12 , wherein the output voltage Vout is monitored by comparing the voltage at the node Vsense 2 with a reference voltage Vovp. The result of comparison determines a signal for controlling the voltage supply circuit 11 .
[0006] Referring to FIG. 3 , it shows a conventional backlight control circuit with LEDs all connected in parallel. As shown in the figure, a backlight control circuit 2 comprises a backlight control integrated circuit 20 , wherein the currents passing through LEDs L 1 -LN are respectively controlled by the current sources CS 1 -CSN. The backlight control integrated circuit 20 comprises a minimum voltage selection circuit 21 which chooses a lowest voltage value among all voltages at cathode ends of the LEDs L 1 -LN, and the error amplifier circuit 13 compares the lowest voltage value with a reference voltage to generate a signal controlling the voltage supply circuit 11 . Thus, the output voltage Vout is under control so that all current source circuits are provided with sufficient operating voltage for normal operation, and all LEDs can illuminate normally thereby.
[0007] Similarly, the backlight control integrated circuit 20 can further comprise an over voltage protection circuit 12 as the one described above.
[0008] The number of LEDs that are allowed to be connected all in series or all in parallel in the above conventional arrangements is limited, and naturally this leads to connecting the LEDs partially in series and partially in parallel (series-parallel connection). FIG. 4 shows a prior art arrangement of such series-parallel connection in which the backlight control integrated circuit 10 shown in FIG. 1 is employed to provide voltage to a series-parallel connection circuit of LEDs. However, it only checks the current on the path of LEDs L 1 -LN but does not check those on the other paths.
[0009] Another prior art arrangement is shown in FIG. 5 which employs the backlight control integrated circuit 20 shown in FIG. 3 to compose a series-parallel connection circuit for LEDs.
[0010] In the above circuits shown in FIGS. 1 , 4 , and 5 , the larger the number of the series-connected LEDs is, the higher the required output voltage Vout is. Correspondingly, a higher voltage rating capacitor is required for the output capacitor, which will increase the total cost of the backlight control circuit.
SUMMARY OF THE INVENTION
[0011] In view of the foregoing, it is therefore an objective of the present invention to provide a backlight control circuit capable of supplying a relatively high output voltage by means of a relatively low voltage rating capacitor, to solve the above-mentioned cost and other issues.
[0012] In accordance with the foregoing and other objectives of the present invention, and as disclosed by an embodiment of the present invention, a backlight control circuit is provided, which comprises a voltage supply circuit, which receives an input voltage from an input terminal and generates an output voltage to an output terminal, wherein the output voltage being provided as an operating voltage for a plurality of light emitting devices; at least one input capacitor electrically connected between the input terminal and ground; and at least one output capacitor electrically connected between the output terminal and the input terminal.
[0013] Preferably, the voltage supply circuit further comprises a noise filtering circuit to avoid a noise problem from the electrical connection between the output capacitor and the input terminal.
[0014] Moreover, a power supply with a low internal impedance is preferred for providing the input voltage; in other words, a power supply having a low impedance for both current sourcing and current sinking is preferred.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] These and other features, aspects, and advantages of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:
[0016] FIG. 1 is a schematic circuit diagram showing a prior art circuit including LEDs which are all connected in series and a backlight control circuit thereof;
[0017] FIG. 2 is a schematic circuit diagram showing a conventional over voltage protection circuit;
[0018] FIG. 3 is a schematic circuit diagram showing a prior art circuit including LEDs which are all connected in parallel and a backlight control circuit thereof;
[0019] FIG. 4 is a schematic circuit diagram showing a prior art circuit including LEDs which are connected partially in series and partially in parallel, and a backlight control circuit thereof;
[0020] FIG. 5 is a schematic circuit diagram showing another prior art circuit including LEDs which are connected partially in series and partially in parallel, and a backlight control circuit thereof;
[0021] FIG. 6 is a schematic circuit diagram showing a backlight control circuit according to an embodiment of the present invention;
[0022] FIG. 7 is a diagram for explaining the internal working model of a power supply;
[0023] FIGS. 8 and 9 are schematic circuit diagrams showing the arrangement of a noise filtering circuit in the voltage supply circuit 11 ;
[0024] FIGS. 10A-10D are diagrams showing four embodiments of regulator circuits;
[0025] FIGS. 11A and 11B are diagrams showing two embodiments of low-pass filter circuits; and
[0026] FIGS. 12A and 12B are diagrams showing two embodiments of spike voltage clamper circuits.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0027] The voltage of a white or blue LED may vary in a range from 3.3V to 4V due to manufacture deviation. To cope with it, in circuit design, the necessary output voltage Vout is calculated by 4V multiplied by the number of LEDs connected in series in a path. That is, if the number of LEDs in a path is more than or equal to 13, the Vout is higher than 50V. (4*13=52>50)
[0028] Considering the demand for thin thickness, small size, low parasitic resistance, environmental protection, and cost effectiveness, ceramic capacitor is currently the best choice for an LED backlight circuit. The nominal voltage ratings of ceramic capacitors are classified as: 6.3V/10V/16V/25V/50V/100V/200V/ . . . , and the corresponding cost greatly increases as the rating goes higher (i.e., using a higher voltage rating capacitor). For example, the cost of a 100V rating capacitor is twice more than that of a 50V rating capacitor. In the prior art circuits shown in FIGS. 1 , 4 , and 5 , if the number of LEDs in the series-connection path is more than or equal to 13, a 100V rating capacitor must be used as the output capacitor Cout.
[0029] The present invention is more cost-saving because it can use a relatively low voltage rating capacitor as the output capacitor Cout. FIG. 6 shows a circuit diagram according to an embodiment of the present invention, wherein a backlight control circuit 3 comprises a backlight control integrated circuit 30 and two external capacitors Cin and Cout electrically connected therewith. The input voltage Vin is provided by a power supply 5 . One feature of the present invention is that the output capacitor Cout is electrically connected to the input terminal instead of ground. Therefore, the span voltage of the output capacitor Cout becomes Vout-Vin, and a capacitor with voltage rating lower than Vout can be used.
[0030] The input voltage Vin to a white LED backlight control circuit in currently popular applications, such as notebook computers or other products, is probably provided by 3 or 4 Li-ion batteries or Li-polymer batteries connected in series, which is under about 24V (charger voltage included) and typically between about 10V to about 24V; however, when the battery energy is close to running out, it can be under 10V. The maximum output voltage Vout is about 40V to about 60V, for 10-15 white LEDs connected in series. In some other applications, the input voltage Vin is provided by two Li-ion batteries or Li-polymer batteries, which is under about 15V (charger voltage included) and typically between about 6.6V to about 15V; however, when the battery energy is close to running out, it can be under 6.6V. The maximum output voltage Vout is about 24V to about 32V for 6-8 white LEDs connected in series. (In other words, the voltage supply circuit 11 is usually a boost converter circuit.) Referring to the prior art circuits shown in FIGS. 1 , 4 , and 5 , these circuits must use a 100V rating capacitor as its output capacitor when the output voltage Vout is higher than 50V. However in contrast, according to the embodiment of the present invention under the same condition, the input capacitor Cin can be a 25V rating capacitor and the output capacitor Cout can be a 50V rating capacitor. (Or, the output capacitor Cout can even be a 25V rating capacitor or a capacitor of other lower ratings, depending on the difference between the output voltage Vout and the input voltage Vin.) Thus, it is not required to use a capacitor having a rating equal to or higher than the output voltage Vout.
[0031] Because the output terminal is connected to the input terminal via the output capacitor Cout, a noise in the output terminal (for example, a ripple noise) may be transmitted into the backlight control circuit 3 through the input terminal. The present invention discloses a solution thereto, as described below.
[0032] Preferably, the power supply providing the input voltage Vin is a power supply having a low internal impedance. FIG. 7 shows a working model of the power supply for providing the input voltage Vin, wherein the power supply 5 comprises an ideal voltage supply source Vs and two paths: a current sourcing path 51 composed of an ideal diode 52 (having a conductive span voltage of zero) and a resistor Rs 1 , and a current sinking path 53 composed of an ideal diode 54 and a resistor Rs 2 . (Rs 1 , Rs 2 are referred to as “internal impedances”.)
[0033] According to the inventor's analysis, when a noise at the output terminal is coupled to the input terminal via the output capacitor Cout, the noise coupling effect correlates to the Cout/Cin ratio, and the resistances of Rs 1 and Rs 2 . The larger the Cout/Cin ratio, or the resistances of Rs 1 and Rs 2 are, the more obvious the noise coupling effect is.
[0034] Consequently, according to the present invention, the power supply 5 which provides input voltage Vin is preferably a power supply with low internal impedance, i.e., low Rs 1 and Rs 2 resistances. Preferred power supplies include: Li-ion batteries, Li-polymer batteries, NiCd batteries, NiMH batteries, fuel cells, and a power supply connected in parallel with a super capacitor (having a capacitance higher than 0.1 F), etc.
[0035] Further, to avoid the noise influence on the voltage supply circuit 11 , the backlight control circuit 30 preferably comprises a circuit with noise filtering function, such as a regulator circuit, a filter circuit such as a low-pass filter circuit, or a spike voltage damper circuit. The input voltage Vin is transmitted into the voltage supply circuit 11 only after it has been subject to noise filtering. Such noise filtering circuit can be disposed inside or outside the integrated circuit 30 .
[0036] FIG. 8 better illustrates the noise filtering concept described above, wherein the voltage supply circuit 11 comprises a group of devices which are sensitive to noises (noise sensitive device group 70 ) and a group of devices which are insensitive to noises (noise insensitive device group 80 ). The noise sensitive device group 70 includes, e.g., a reference voltage supplier circuit, a current bias circuit, an error amplifier circuit, a comparator circuit, an oscillator circuit, a voltage sensor circuit, a current sensor circuit, and a temperature sensor circuit, etc. The noise insensitive device group 80 includes, e.g., a level shifter circuit, a power stage circuit, etc. (The details of a voltage supply circuit is well known to the people skilled in the art, so the detailed circuit structure is omitted for simplicity.) The input voltage Vin at the input terminal passes through a noise filtering circuit 60 to be subject to noise filtering, and afterwards supplied to the noise sensitive devices of the group 70 , while the noise insensitive devices of the group 80 directly receive the unfiltered input voltage Vin. As an alternative, referring to FIG. 9 , the noise insensitive devices of the group 80 can also receive the filtered input voltage Vin. The noise filtering circuit 60 is disposed inside the voltage supply circuit 11 in FIGS. 8 and 9 , yet the noise filtering circuit 60 certainly can be disposed outside the voltage supply circuit 11 or even outside the backlight control integrated circuit 30 .
[0037] As described in the above, the noise filtering circuit 60 can be a regulator circuit, a filter circuit such as a low-pass filter circuit, or a spike voltage clamper circuit. FIGS. 10-12 illustrate several possible embodiments of such circuits.
[0038] FIGS. 10A-10D show four embodiments of the regulator circuits according to the present invention, each of which can regulate the input voltage Vin into a noiseless internal voltage Vinternal for operation of internal devices inside the voltage supply circuit 11 .
[0039] FIGS. 11A and 11B show two embodiments of low-pass filter circuits according to the present invention, each of which can filter high frequency noises in the input voltage Vin and transform it into an internal voltage Vinternal for operation of internal devices inside the voltage supply circuit 11 .
[0040] FIGS. 12A and 12B show two embodiments of spike voltage damper circuits according to the present invention, each of which can filter voltage spikes in the input voltage Vin and transform it into an internal voltage Vinternal for operation of internal devices inside the voltage supply circuit 11 .
[0041] Other embodiments of regulator circuits, low-pass filter circuits, and spike voltage clamper circuits are achievable by the persons skilled in the art under the spirit and within the scope of the present invention, based on respective circuit design requirements.
[0042] The present invention has been described in considerable detail with reference to certain preferred embodiments thereof, but they are only for illustration of the spirit, rather than for limiting the claim scope of the present invention. For those who are skilled in the art, modifications and variations are readily achievable. For example, although the present invention is more advantageous in the situation where high output voltage is required because of series connection of LEDs, it can similarly apply to the situation where LEDs are all connected in parallel, as shown in FIG. 2 . Further, in all of the embodiments, one can insert a circuit which does not affect the primary function, such as a switch circuit, a diode circuit, a resistor circuit and so on, between any two devices which are shown to be directly connected. Furthermore, the embodiments described above show only one capacitor at each of the input terminal and the output terminal, but of course one can provide more than one capacitor at either the input terminal or the output terminal. Moreover, the input capacitor Cin and the output capacitor Cout are shown to be discrete devices in the above, yet Cin and Cout can be integrated in the backlight control integrated circuit 30 . In addition, the backlight control integrated circuit 30 of the above embodiments comprises current source circuits, a minimum voltage selection circuit, and an error amplifier circuit to provide a signal 15 to control the voltage supply circuit 11 , which is only one example of the possible arrangements of the backlight control integrated circuit 30 ; there can be other arrangements to control the voltage supply circuit 11 for the backlight control integrated circuit 30 . Still further, the light emitting device, although shown as LED in the above, are not limited thereto but can be other light emitting devices such as an organic light emitting diode. And the word “backlight” in the term “backlight control circuit” is not to be taken in a narrow sense that the circuit has to control the backlight of a screen; the present invention can be applied to “active light emission display”, or “LED illuminator”, or other apparatuses that employ light emitting devices. Therefore, all modifications and variations based on the spirit of the present invention should be interpreted to fall within the scope of the following claims and their equivalents. | The present invention discloses a backlight control circuit, comprising: a voltage supply circuit, which is a boost converter circuit for receiving an input voltage from an input terminal and generating an output voltage to an output terminal, the output voltage being provided as an operating voltage for a plurality of light emitting devices; at least one input capacitor electrically connected between the input terminal and ground; and at least one output capacitor electrically connected between the output terminal and the input terminal. | 7 |
CROSS-REFERENCE TO RELATED APPLICATION
This is a continuation-in-part of Ser. No. 090,776, filed Aug. 28, 1987 now abandoned.
BACKGROUND OF THE INVENTION
This invention relates to anti-static compositions for fibrous materials, such as fiberglass insulation, and methods to applying same to such materials in mat form.
Fiberglass insulation is a poor dissipator of static electricity. Any mechanical agitation, such as sawing, cutting, chopping, etc., during manufacture, handling and/or installation of fiberglass insulation generates static electricity which is not dissipated for several hours in some cases. Particles of fiberglass with the same electrical charge repel each other and thereby generate a dust which causes not only an unpleasant and unhealthy environment for workers, but also a loss of material.
Anti-static compositions including one or more quaternary ammonium compounds have been used to neutralize static electric charges. Such a composition is disclosed in U.S. Pat. No. 4,314,308. Many of these compositions tend to be toxic, inflammable and/or corrosive, particularly when exposed to hot glass particles.
Prior attempts have been made to apply anti-static compositions to fiberglass mats during the manufacturing process at the forming end of the production line. However, these attempts generally have been unsuccessful because the resulting mat did not retain anti-static properties.
SUMMARY OF THE INVENTION
An object of the invention is provide an anti-static composition which can be applied to a fibrous material, such as fiberglass insulation, and is capable of providing the material with a long-lasting ability to dissipate static electrical charges.
Another object of the invention is to provide a method for applying an anti-static composition to a mat of fibrous material, such as fiberglass insulation, during the manufacturing process and in a manner whereby the material retains the ability to dissipate static electrical charges for relatively long time periods even though subjected to mechanical agitation.
Other objects, aspects and advantages of the invention will become apparent to those skilled in the art upon reviewing the following detailed description, the drawing and the appended claims.
The anti-static composition provided by the invention is an aqueous solution containing as the active anti-static agent two water soluble quaternary ammonium compounds, one containing an inorganic anion and serving as the primary anti-static ingredient and the other containing an nitrate or nitrite which serves as an corrosion inhibitor and a stabilizer. The active anti-static agent also includes a glycol humectant. The anti-static agent preferably also contains a sufficient amount of a non-corrosive acid to adjust the pH of the composition to about 5 to about 7 and a sufficient amount of a suitable dye to impart a discernable coloration to the composition.
In a preferred embodiment, the anti-static composition is sprayed in atomized form onto the top surface of a fiberglass insulation mat after it has passed through the curing oven and as it moves through the cooling zone in the manufacturing process. The cooling air being drawn through the warm mat assists in causing the anti-static composition to penetrate through substantially the entire thickness of the mat. When the mat is subsequently agitated, such as by sawing, chopping, blowing, etc., generation of static electricity which causes dusting is substantially reduced by the presence of the anti-static agent in the mat material.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a schematic representation of a portion of a production line for fiberglass insulation mat illustrating a system for applying an anti-static composition during the manufacturing process.
FIG. 2 is a top view of the mat production line and application system illustrated in FIG. 1.
DESCRIPTION OF PREFERRED EMBODIMENTS
While the anti-static composition of the invention can be used on various types and forms of materials to inhibit generation of and/or dissipate static electrical charges, it is particularly adaptable for use on fiberglass insulation for application during the manufacture of fiberglass insulation in mat form and will be described in connection with that application.
The drawings are schematic representations of a portion of a conventional fiberglass insulation mat-forming line. Molten glass is fiberized into filaments which are sprayed into a continuously moving forming/carrier chain 12. The glass filaments fall onto the moving chain 12 in a random fashion to form a mat 14. The glass fiberizing rate and the traveling speed of the chain 12 determine the thickness of the mat which is usually in the order of 10 to 15 inches.
A suitable bonding agent, such as an urea resin, a phenolic resin, etc., is sprayed onto the glass filaments to bind them together and make the mat 14 resilient and resistant to compression. The bonding agent is heated to a temperature of 120° F. or more for curing as the mat passes through a curing oven 16. After the mat 14 exits from the curing oven 16, it travels over a cooling table 18 including one or more induced draft fans 20 which draw or pulls air down through the warm fiberglass mat as illustrated by arrows 22 to expedite cooling. The warm air exiting from the mat (indicated by arrows 24) is routed to suitable dust recovery equipment 26 for removal of fiberglass particles and other particulate material before being exhausted to the atmosphere. As illustrated by the dashed lines in FIG. 1, the cooling table can include a hood 27.
After the cooled mat leaves the cooling table 18, the ragged edges are trimmed by edge trimming saws 28 and slit into bats 30 of the desired width by a plurality of laterally spaced slitter saws 32. A horizontal saw (not shown) can be used to cut the mat to a desired thickness. The saws can be circular saws as illustrated or band saws. The physical contact between the saws 28 and 32 and the fiberglass generates static electricity. The edge trimming results in waste which is usually chopped into nodules and blown through duct work for packaging. The static electricity generated by the trimming and slitting saws causes the surrounding area to become laden with small dust-like particles, resulting not only in an unpleasant and unhealthy working environment but also a loss of material. The static electricity generated by mechanical agitation during chopping of the waste materials can cause the resulting nodules to cling to the wall of the blower plenum and cause plugging.
In accordance with a preferred embodiment of the invention, a liquid anti-static composition, atomized into mist-like form, is sprayed downwardly onto the top surface of the mat 14 at a location near the entry of the cooling table 18. The cooling air assists in drawing the fine droplets of the anti-static composition down into the mat 14.
In the specific embodiment illustrated, the anti-static composition is drawn from a storage tank 34 by a suitable pump 36 and pumped through a conduit 38 into a generally horizontal manifold 40 extending transversely above and across the width of the mat 14 near the entry of the cooling table 18. Connected to the manifold 40 is a plurality of laterally spaced, external air atomizing spray nozzles 42 which direct a fine mist-like spray of the anti-static composition over the surface of the mat 14. Air for atomizing is supplied to the nozzles through a suitable manifold and hoses (not shown) or the like connected to a suitable source of compressed air (not shown).
The spray angle of the nozzles 42 is adjusted to provide thorough surface coverage of the mat and to maximize penetration of the anti-static composition into the mat. This spray angle, which is usually about 30° to 45° from the vertical, varies depending on the travel speed of the mat, mat thickness, cooling air flow and mat composition. The nozzles preferably are situated so that the spray patterns are centered on locations corresponding to the saws.
Various suitable anti-static compositions are capable of imparting electrical charge dissipation properties to the fiberglass mat can be used. The preferred anti-static composition is an aqueous solution containing an active anti-static agent including, based on the total weight of said anti-static agent,
about 90 to about 97 weight % of a first water soluble quaternary ammonium compound having the general formula ##STR1## wherein R 1 is a substituted or unsubstituted aliphatic group containing 8 to 15 C atoms,
R 2 , R 3 and R 4 is an aliphatic group containing 1 or 2 carbon atoms, and
X is an inorganic anion;
about 1 to about 3 weight % of a second water soluble quaternary ammonium compound having the general formula ##STR2## wherein R 5 is a substituted or unsubstituted aliphatic group containing 16 to 24 C atoms,
R 6 , R 7 and R 8 is a substituted or unsubstituted aliphatic group containing 1 or 2 C atoms, and
Y is nitrate or nitrite; and
about 1 to about 5 weight % of a glycol having humectant properties.
Both the first and second quaternary ammonium compounds are water soluble. While both can be cationic, anionic or nonionic, cationic compounds presently are preferred because they provide a more rapid dissipation of static electrical charges.
The first quaternary ammonium compound serves as the primary anti-static ingredient. While compounds having higher or lower molecular weights can be used, those having a molecular weight within the range of about 150 to about 400 are preferred.
As indicated in the formula above, the R 1 group in the first quaternary ammonium compound can be substituted or unsubstituted aliphatic or cyclic containing 8 to 15 C atoms. Suitable substituents include ##STR3## and --CNH 2 --. The R 1 group can be branched or straight chain. Preferably it is an alkane, but can be an alkene aliphatic with unsaturation such as ethylenic unsaturation.
Representative cyclic R 1 groups include cycloalkyl, cycloalkenyl or aromatic groups such as phenyl or benzyl.
X can be any inorganic anion which results in the quaternary ammonium compound being water soluble. Suitable anions include chloride, bromide, fluoride, iodide, nitrate, sulfate and phosphate. Chloride and bromide are preferred because of cost considerations.
Suitable first quaternary ammonium compounds containing cyclic R 1 groups include compounds which are a mixture of n-alkyl dimethyl benzyl ammonium chlorides and n-alkyl dimethyl ethylbenzyl ammonium chlorides.
Quaternary ammonium compounds containing alkyl R 1 groups are preferred. A particularly suitable, commercially available alkyl type compound is CHEMQUAT C-33W, marketed by Chemax, Inc., which is a 33% aqueous solution of cocotrimethyl ammonium chloride.
The amount of the first quaternary ammonium compound in the active anti-static agent is about 90 to about 97, preferably about 93 to about 96 weight %, based on the total weight of the active anti-static agent.
The second quaternary ammonium compound also is an anti-static agent. However, it also serves as a corrosion inhibitor by virtue of the nitrate or nitrite anion and its low volatility stabilizes the composition in the event the composition contacts a hot glass fragment in the mat during application, which can occur quite often during normal production.
The R 5 group in the second quaternary ammonium compound can be the same as the R 1 group in the first quaternary ammonium compound, except it contains 16 to 24 carbon atoms. The R 5 group preferably is a substituted or unsubstituted aliphatic group. While compounds having higher and lower molecular weights can be used, ones having a molecular weight within the range of about 300 to about 600 are preferred.
A particularly suitable, commercially available compound including a substituted aliphatic R 5 group is CYASTAT S N, marketed by American Cyanamide Co., which is 50% solution of stearamidopropyl dimethyl-β-hydroxyethyl ammonium nitrate in a 25% isopropyl alcohol-water mixture.
The amount of the second quaternary ammonium compound in the active anti-static agent is about 1 to about 5, preferrably about 2 to about 3 weight %, based on the total weight of the anti-static agent.
The glycol serves as a humectant. That is, it increases the humidity or moisture content on the surface of the fiberglass filaments, thereby increasing the humidity or moisture content within the fiberglass mat which assists in the dissipating static electrical charges. The glycol used should be nonflammable at the temperature of the mat and hot glass fragments therein when the mat reaches the cooling table. Suitable glycols include propylene glycol, ethylene glycol and hexylene glycol. Propylene glycol is preferred because it is non-toxic and a food-approved humectant.
The active anti-static agent preferably includes a sufficient amount of an acid, preferably an inorganic acid, to adjust the pH to about 5 to about 7 which assists in preventing precipitation of the small amount of free amines normally present in the quaternary ammonium compounds. Precipitation of these amines can cause plugging of the spray nozzles. While other suitable acids can be used, sulfuric acid presently is the most preferred because it is not corrosive at pH within the range of 5 to 7.
A sufficient amount of a compatible dye to impart a discernible coloration to the anti-static composition preferably is used so that the composition will not be mistaken for water or another clear liquid. Also, the coloration helps users in finding the fluid level in a container. Generally, a trace amount, e.g. about 0.0001 weight % based on a total weight of the active anti-static agent, is sufficient for this purpose. A particularly suitable commercially available dye is PYLAKLOR DETERGENT BLUE marketed by Pylam Products.
When applied by spray nozzles as in the illustrated embodiment, the viscosity of the anti-static composition is adjusted by diluting with sufficient water to permit atomization into fine, mist-like droplets. Generally, the amount of the aqueous anti-static composition sprayed onto the mat contains about 2 to about 50, preferably about 4 to about 7 weight % of the active anti-static agent, based on the total weight of the anti-static composition.
The amount of anti-static composition sprayed onto the mat is that which is effective to provide the fiberglass material with the ability to dissipate static electrical charges, preferably to a negative charge no less than -3,000 volts. Generally, the amount applied is equivalent to at least 25, preferably 150 to 1,000, parts of the active anti-static agent per million parts of the mat material. The feed rate at which the anti-static composition is pumped into the manifold is regulated, depending on the thickness and thus the weight of the mat, to provide the desired dosage of the anti-static agent.
The cooling air drawn through the mat can be controlled so that the anti-static composition penetrates through substantially the entire thickness of the mat. The flow of the cooling air should be regulated so that the air exiting from the bottom of the mat is not entrained with the anti-static composition.
The active ingredients of the anti-static agent usually remain in the mat material and provide effective dissipation of static electrical charges for several months, even when the edge trimmings and other waste material is chopped into nodules. For applications where a cooling table is not available, the same type of penetration can be obtained by drawing air through material to which the anti-static composition is being applied.
The application of the anti-static composition during manufacturing provides several advantages. Visible dust around the machinery downstream of the cooling table, particularly the cutting saws, is substantially reduced. This not only improves industrial hygiene but reduces the loss of material. That is, dust particles, which otherwise would become airborne because of a large negative charge, remain as part of the mat rather than ending up in a dust collection system where they cannot be used. Since the active anti-static ingredients remain in the fiberglass material for several months, generation of dust is minimized when the fiberglass insulation is installed in buildings, either as bats or by blowing chopped material. Also, it has been found that the life of cutting saws is increased when the preferred anti-static composition is applied to the mat. While not fully understood at this time, it appears that the anti-static agent forms a protective surface coating on the saw blades. The wear life of saw blades is increased from 2 or 3 days up to as much as a month, depending on the type of fiberglass.
The anti-static composition also can be used with bulk fiberglass materials by applying directly to the material or spraying into equipment at locations where static electricity is normally generated, e.g., in the plenum of blowers for packaging equipment.
Without further elaboration, it is believed that one skilled in the art, using the preceding description, can utilize the present invention to its fullest extent. The following example is presented to exemplify a preferred embodiment of the invention and should not be construed as a limitation thereof.
EXAMPLE
A test was run on a fiberglass mat Production line including edge trimming saws, slitter saws and a horizontal saw, to evaluate the effectiveness of an anti-static composition of the invention. The atmospheric conditions were relatively humid and cool and, therefore, not conducive to producing high amounts of dust and static electricity. The anti-static agent used in this test contained 95 weight % CHEMQUAT C-33W, 2 weight % CYASTAT SN, 3 weight % propylene gylcol, a trace of PYLAKOR DETERGENT BLUE dye to provide a blue coloration and a sufficient amount of sulfuric acid to reduce the pH to 5. The anti-static agent was diluted by adding 7 parts of water to 1 part of the anti-static agent to produce an anti-static composition for spraying onto the mat.
Six Binks Model 610 external air atomizing nozzles were installed above the mat at locations near the entry of the cooling table. Air was supplied to the nozzles through two 3/8 inch hoses. The spray patterns of the nozzles were centered on locations corresponding to the position of the edge trimming and slitter saws and the nozzles were set to deliver the anti-static composition at a feed rate equivalent to about 500 parts of the anti-static agent per million parts of the mat.
Observations were made of the visual dust present prior to application the anti-static composition and during a 11/2 hour period after application began. Measurements of the static electrical charges were made at approximately 30 minute intervals with a 3M Model 703 static meter on both sides of the mat (a) at the oven exit, (b) at the edge trim saw exit and (c) at the horizontal saw exit during the same time period. There was a substantial reduction (estimated to be 60-70% or more) in the visual dust present in the area surrounding the saws throughout the test period. The voltage measurements are tabulated in Table I below.
TABLE I______________________________________Voltage Readings Edge Trim Horizontal Oven Exit Saw Exit Saw Exit______________________________________BeforeApplication ofAnti-StaticComp.Side 1 -500 -5,000 -50,000Side 2 -500 -5,000 -50,00030 MinutesAfter Start ofTest PeriodSide 1 -500 -400 to -500 -1,000 to -2,500Side 2 -500 -400 to -500 -700 to -1,900At End ofTest periodSide 1 -500 -400 to -500 -1,500 to -2,500Side 2 -500 -300 to -400 -1,900 to -2,500______________________________________
From these test results, it can be seen that the use of an anti-static composition of the invention substantially reduced the static electrical charges generated by the edge trimming saw and the horizontal saw. Generally, dusts do not become a problem as long as the static electrical charge is maintained less negative than about -3,000.
Tests performed during less humid atmospheric conditions have shown even a more dramatic reduction in the visual dust and the static electrical charges. In other tests, the edge trimmings were chopped in a hammermill and voltage measurements made on the chopped material at the exit of the hammermill. It was found that the static electrical charge on this material was in the range of -500 to -1,500.
From the foregoing description, one skilled in the art can easily ascertain the essential characteristics of the invention and, without departing from the spirit and scope thereof, make various changes and modifications to adapt it to various usages. | A fibrous material, such as fiberglass insulation, is treated to minimize the generation of static electricity when subjected to agitation, such as by sawing, chopping, blowing, etc. during manufacturing, handling and/or installation, by applying an anti-static composition onto a mat of the material during the manufacturing process. The anti-static composition preferably is an aqueous solution containing an active anti-static agent including a nonflammable glycol humectant and two water soluble quaternary ammonium compounds, one serving as the primary anti-static ingredient and the other serving as a corrosion inhibitor and stabilizer. The anti-static composition is sprayed onto the surface of the mat as it travels through the cooling zone and the cooling air drawn through the mat causes the anti-static agent to penetrate through substantially the entire thickness of the mat. | 8 |
FIELD OF THE INVENTION
The present invention relates to a method for fabricating a semiconductor device and, more particularly, to a method for fabricating a semiconductor device with an ultra-shallow epi-channel of which the channel length is 100 nm or less.
DESCRIPTION OF THE PRIOR ART
Generally, in transistors such as MOSFETs or MISFETs, the surface area of a semiconductive substrate, which is disposed below a gate electrode and a gate dielectic layer, functions to allow the currents to flow due to the electric field applied to source/drain in a state that a voltage beyond the triggering is applied to the gate electrode. Therefore, this area is called “channel”.
In addition, characteristics of these transistors are determined by the dopant concentration of the channel. Accurate doping of the channel is very important since the general properties such as threshold voltage (V T ) and drain currents (I d ) of a transistor are determined by the dopant concentration.
As a doping method of the channel, channel ion implantation (or threshold voltage adjusting ion implantation) using ion implantation method are widely used. The channel structures that can be formed using the above ion implantation method include a flat channel having a constant concentration within a channel in depth, the buried channel formed the channel at a specific depth away from the surface, the retrograde channel having a low surface concentration and whose concentration within the channel increases rapidly in a depth direction, etc.
Among the above channels, the retrograde channel is widely used in a high performance microprocessor of which the channel length is 0.2 m or less. The retrograde channel is formed using heavy ion implantation of In, As, Sb, etc. Since the retrograde channel has high surface mobility due to the low surface dopant concentration, it has been applied to high performance devices with high driving current characteristics.
However, with decreasing the channel length, the required channel depth must be shallower. Also, the ion implantation techniques have limitations when implementing on the formation of retrograde channel of which the channel depth becomes 50 nm or less.
In order to meet these demands, there has been proposed the epi-channel structure in which an epitaxial layer is formed on a channel doping layer.
FIG. 1A is a cross-sectional diagram of a semiconductor device with a conventional epi-channel structure.
Referring to FIG. 1A, a gate dielectric layer 12 and a gate electrode 13 are formed on a semiconductive substrate 11 , and the epi-channel consisting of an epitaxial layer 14 and a channel doping layer 15 is formed on the semiconductive substrate 11 disposed below the gate dielectric layer 12 . A high-concentration source/drain extension (SDE) region 16 and a source/drain region 17 are formed on both sides of the epi-channel.
However, since it is difficult to control dopant loss and diffusion of the channel doping layer 15 due to the process of forming the epitaxial layer and the following thermal process, there is a problem to implement the improved on/off current characteristic required for the high performance device with the epi-channel structure.
In order to solve this problem, there has been proposed a method for implementing a delta doped epi-channel by forming a dual epitaxial layer consisting of a doped epitaxial layer doped in a step shape and an undoped epitaxial layer, as shown in FIG. 1 B.
FIG. 1B shows the change of a doping profile according to the transient enhanced diffusion (TED) or the thermal budget, followed by the forming of the delta doped epi-channel. Referring to FIG. 1B, since the step-like delta doping profile of the epi-channel below the gate dielectric layer (Gox) does not maintain an ideal delta doping profile (P 1 ) due to the TED or the thermal budget, there occurs the broadening (P 2 ) of the doping profile.
Accordingly, in case where the delta doped epi-channel is formed using the dual epitaxial layer consisting of the doped epitaxial layer and the undoped epitaxial layer, since a low concentration epitaxial layer of 1×10 19 atoms/cm 3 or less cannot be deposited, the diffusion (D) of dopants due to the TED or the thermal budget is too excessive, so that there is a limitation when implementing the delta doped epi-channel of which the channel depth is 30 nm or less.
In order to improve these problems, there is proposed a method in which after forming a delta doped n-channel doping layer having a precisely controlled concentration by ultra low energy boron ion implantation, laser thermal annealing (LTA) process is instantaneously performed to prevent the diffusion of the delta doped n-channel doping layer (referring to FIGS. 2 A and 2 B).
FIGS. 2A and 2B are cross-sectional diagrams showing the method for fabricating a semiconductor device with an epi-channel formed by ultra low energy ion implantation and by laser thermal annealing (LTA) process.
As shown in FIG. 2A, a field oxide layer 22 with shallow trench isolation (STI) structure is formed on a semiconductive substrate 21 , and P-type dopants are ion-implanted into the semiconductive substrate 21 to thereby form P-type well 23 . Sequentially, boron ions are implanted under ultra low energy (1 keV) to form a delta doped channel doping layer 24 .
Then, the laser thermal annealing (LTA) process of 0.36 J/cm 2 to 0.44 J/cm 2 is directly performed without any pre-amorphization for amorphizing a surface of the semiconductor substrate 21 . As can be seen in FIG. 2B, the laser thermal annealing process suppress the re-distribution of boron within the channel doping layer 24 , as well as changing the channel doping layer 24 into chemically stable channel doping layer 24 A.
As shown in FIG. 2B, an epitaxial layer 25 is selectively grown on the channel doping layer 24 A at a temperature of 600 to 800 to thereby form the super steep retrograde (SSR) epi-channel structure.
Meanwhile, the TED of the delta doped channel doping layer can be prevented by using rapid thermal annealing (RTA) process as well as the laser thermal annealing process.
FIG. 3 A and FIG. 3B are the graphs showing the doping profiles of SSR epi-channel formed by selectively epitaxial growth on boron doped specimens of 1 KeV ion implanted or 5 KeV ion implanted, respectively.
As can be seen from FIGS. 3A and 3B, in the doping profiles of SSR epi-channel formed using the ultra low energy ion implantation, as the ion implantation energy becomes lower, a distribution range of delta doping becomes narrower. Since this delta doping which is narrowly distributed as shown in FIG. 3A can remarkably reduce the junction capacitance of device and the junction leakage current, it is an essential technique in manufacturing the low-power and high-efficiency semiconductor device.
However, the ultra low energy ion implantation has disadvantages that the available energy is limited, since it is difficult to extract enough ion beam currents at such ultra low energy range, as well as the manufacturing time is taken longer.
SUMMARY OF THE INVENTION
It is, therefore, an object of the present invention to provide a method for fabricating a semiconductor device with epi-channel structure, which is adapted to overcome an available energy limitation and to improve the productivity by providing the method of SSR epi Channel doping by boron-fluoride compound ion implantation without using ultra low energy ion implantation.
In addition, it is another object of the present invention to provide a method for fabricating the semiconductive device with epi-channel structure adapted to prevent the crystal defects caused by the epitaxial growth on ion bombarded and fluorinated channel doping layer.
In an aspect of the present invention, there is provided a method for forming the epi-channel of a semiconductor device, which comprises the steps of: a) forming a channel doping layer below the surface of a semiconductive substrate by implanting boron-fluoride compound ions containing boron; b) performing the annealing process to remove fluorine ions injected within the channel doping layer; c) performing a surface treatment process to remove the native oxide layer formed on a surface of the channel doping layer and simultaneously remove remaining fluorine ions within the channel doping layer; and d) growing an epitaxial layer on the channel doping layer using the selective epitaxial growth method.
In another aspect of the present invention, there is provided a method for fabricating a semiconductor device, which comprises the steps of: a) forming a channel doping layer below the surface of a semiconductive substrate by to implanting boron-fluoride compound ions containing boron; b) performing the first annealing process to remove fluorine ions, injected during above channel doping implantation, within the channel doping layer; c) performing the surface treatment process to remove the native oxide layer formed on the surface of the channel doping layer and simultaneously remove remaining fluorine ions within the channel doping layer; d) growing the epitaxial layer on the channel doping layer; e) sequentially forming a gate dielectric layer and a gate electrode on the epitaxial layer; f) forming source/drain extension regions arranged at edges of the gate electrode, wherein the source/drain extension region is shallower than the channel doping layer; g) forming spacers contacted with both sides of the gate electrode; h) forming source/drain regions arranged at edges of the spacers of the gate electrode, wherein the source/drain regions are deeper than the channel doping layer; and i) performing the second annealing process, for the activation of dopants contained in the source/drain extension regions and the source/drain regions, at a temperature suppressing the diffusion of the channel doping layer.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objects and aspects of the invention will become apparent from the following description of the embodiments with reference to the accompanying drawings, in which:
FIG. 1A is a cross-sectional diagram of a semiconductor device with a conventional epi-channel;
FIG. 1B shows the change of a doping profile in the epi-channel according to TED or thermal budget;
FIGS. 2A and 2B are cross-sectional diagrams showing a method for fabricating a semiconductor device with epi-channel formed using ultra low energy ion implantation and laser thermal annealing (LTA) process;
FIG. 3A is a graph showing doping profiles of SSR epi-channels formed by using selective epitaxial growth on 1 KeV boron ion implanted specimens;
FIG. 3B is a graph showing a doping profile of SSR epi-channel formed by using selective epitaxial growth on 5 KeV boron ion implanted specimens;
FIG. 4 is a graph showing the distributions of boron concentration when B + ions or 49 BF 2 + ions are implanted into a silicon substrate,respectively;
FIGS. 5A to 5 F are cross-sectional diagrams illustrating a method for fabricating an NMOSFET in accordance with a first embodiment of the present invention;
FIGS. 6A to 6 F are cross-sectional diagrams illustrating a method for fabricating a CMOSFET in accordance with a second embodiment of the present invention;
FIG. 7 is a cross-sectional diagram of a CMOSFET in accordance with a third embodiment of the present invention;
FIG. 8 is a cross-sectional diagram of a CMOSFET in accordance with a fourth embodiment of the present invention;
FIG. 9 is a cross-sectional diagram of a CMOSFET in accordance with a fifth embodiment of the present invention;
FIG. 10 is a cross-sectional diagram of a CMOSFET in accordance with a sixth embodiment of the present invention;
FIG. 11 is a cross-sectional diagram of a CMOSFET in accordance with a seventh embodiment of the present invention; and
FIG. 12 is a graph illustrating the distributions of boron concentrations within an SSR epi-channel in which 49 BF 2 + ions are implanted into a channel region.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Hereinafter, preferred embodiments of the present invention will be descried in detail with reference to attached drawings.
The present invention proposes a method for increasing an ion implantation energy used to form a channel doping layer in forming an epi-channel structure, in which a molecular ion beam containing dopant ions is utilized.
Embodiments that will be described below use 49 BF 2 + or 30 BF + , which are extracted from BF 3 gas, as molecular ion beams for forming the channel doping layer.
Compared with a boron (B + ) ion implantation, 49 BF 2 + ion implantation has the same ion implantation depth at 4.5 times ion implantation energy. In addition, since it is possible to implantation ions at 4.5 times higher energy, the manufacturing process can be performed using an ordinary low energy ion implantation apparatus without any ultra low energy ion implantation apparatus. Further, under the same ion implantation energy, since the ion implantation depth is shallower compared with the case of the boron ions, the delta doping of which a width is narrower has more adaptable characteristic.
Furthermore, other kind of ions extracted from the BF 3 gas is 30 B + . The 30 B + ions are ions extracted by selecting a mass of 30 through a mass analyzing of ion beams using BF 3 gas. 30 B + ion has half the bonding number of fluorine as many as 49 BF 2 + ion. Also, since 30 BF + ion has half the implantation amount of fluorine as much as 49 BF 2 + ion, it is possible to prevent occurrence of precipitates of fluorine compounds and fluorine bubbles,found after the following thermal annealing process, due to excessive implantation of fluorine.
Additionally, while the 30 B + ion implantation has the same ion implantation depth as the boron ion implantation, there is an advantage that 30 B + ion implantation can use 2.7 times higher ion implantation energy than boron ion implantation.
Even though the ion implantation of molecular ions extracted from the fluorine compound has the advantage that it uses higher energy than that of boron ions, boron ions are inevitably implanted together with fluorine ions since the 30 BF + ion implantation contains fluorine ions, so that the unintended containing of fluorine causes a crystal defect in a following growth of epitaxial layer and possibly degrades a device characteristic due to a filing-up of fluorine ions at gate dielectric or at the interface between the gate dielectric layer and the semiconductor substrate.
Accordingly, the following embodiments utilizes the fluorine compound ions which can form the shallow junction using higher ion implantation energy when forming the channel doping layer, and explains a method for emitting the fluorine ions, which are injected during the implantation of fluorine compound ions, to an exterior through the following annealing process and the surface treatment process.
FIG. 4 is a graph showing a boron concentration distribution of a semiconductor substrate when B + ions or 49 BF 2 + ions are implanted into the silicon substrate.
In FIG. 4, a horizontal axis represents the depth within the substrate, and a vertical axis represents the boron concentration. Curves P 3 or P 4 represent the cases of B + or 49 BF 2 + , respectively. Here, the boron ion implantation is out at an acceleration energy of 5 keV and at a doze of 1×10 14 atoms/cm 3 , and the BF 2 + ion implantation is carried out at an acceleration energy of 5 keV and at a doze of 1×10 14 atoms/cm 3 .
Referring to FIG. 4, in the boron ion implantation, the boron ions are implanted deep into the substrate, and a peak value of profile is disposed at a deeper position than 10 nm. In case of 49 BF 2 + , a peak value of profile is disposed at about 3 nm and the boron concentration decreases rapidly at deeper position.
The curves P 3 and P 4 show different decrease profiles from each other. The curve P 4 has a narrower distribution of boron. Comparing the curve P 3 with the curve P 4 , the peak value of the curve P 4 is higher than that of the curve P 3 . This means that the 49 BF 2 + ion implantation can obtain the same or higher peak concentration using a smaller ion implantation amount than the ion doze of boron (B + ).
FIGS. 5A to 5 F are cross-sectional diagrams illustrating a method for fabricating an NMOSFET in accordance with a first embodiment of the present invention.
As shown in FIG. 5A, the field oxide layer 32 for device isolation is formed on the predetermined portion of a semiconductive substrate 31 using shallow trench isolation (STI) process or local oxidation of silicon (LOCOS) process. Then, P-type dopants are implanted into the semiconductor substrate 31 to form a deep P-type well 33 . Sequentially, P-type dopants are implanted to thereby form a P-type field stop layer 34 that are shallower than the P-type well 33 . Here, boron (B) is used as the P-type dopants for forming the P-type well 33 and the P-type field stop layer.
Next, as the P-type dopants, molecular ions of fluorine compounds such as 49 BF 2 + or 30 BF + are implanted to thereby form a shallow P-type n-channel doping layer 35 whose depth is 10 nm to 50 nm from a surface of the semiconductor substrate 31 .
At this time, 49 BF 2 + or 30 BF + molecular ions extracted from the BF 3 gas are implanted when performing the ion implantation for forming the P-type n-channel doping layer 35 . The implantation of 30 BF + molecular ions has an effect similar to that of 49 BF 2 + molecular ions. In other words, it has an advantage that it can use the ion implantation energy as high as the boron ion implantation in order to have the same ion implantation depth. In addition, the implanted fluorine ions are reduced to half the 49 BF 2 + molecular ions at the same implantation amount as the 49 BF 2 + molecular ions.
Then, as shown in FIG. 5B, a recovery annealing process is carried out. The recovery annealing process recovers a crystal defect in the surface of the semiconductor substrate 31 , which is caused by an ion bombardment in the ion implantation for forming the P-type n-channel doping layer 35 . Also, the recovery annealing process allows the dopants implanted into the P-type n-channel doping layer 35 to be stably combined with adjacent silicon atoms within the crystals and emits fluorine (F) ions as a volatile gas of SiF 4 to an exterior.
For the recovery annealing process, a rapid thermal annealing (RTA) process or a spike rapid thermal annealing (SRTA) process is carried out at a temperature of below 1414 (a melting point of silicon), which can recover the crystal defect, in order to prevent a diffusion of dopants implanted into the P-type n-channel doping layer 35 .
Here, the spike rapid thermal annealing (SRTA) process represents an annealing process (ramping rate: 150 /sec or more, a delay time: 1 sec or less) which increases from a room temperature to a target temperature within a short time and then directly decreases from the target temperature to the room temperature without any delay.
Preferably, the rapid thermal annealing (RTA) process is carried out at a temperature of 600 to 1050 and the spike rapid thermal annealing (SRTA) process is carried out at a temperature of 600 to 1100.
As a result, through the recovery annealing process, the P-type n-channel doping layer 35 is improved as a layer with no crystal defect by stably combining the implanted dopants with the silicon ions of the semiconductor substrate 31 . In other words, fluorine (F) ions are emitted during the annealing process and the boron (B) ions are stably combined with the silicon (Si) ions.
As described above, through the recovery annealing process, the P-type n-channel doping layer 35 is activated as a very shallow P-type n-channel doping layer 35 A, which is chemically stable.
As shown in FIG. 5C, a surface process is carried out at a hydrogen atmosphere in order to remove a native oxide layer (not shown) formed on the shallow P-type n-channel doping layer 35 A after the recovery annealing process. At this time, if the surface process is carried out at the hydrogen atmosphere, the hydrogen (H 2 ) is reacted with the native oxide layer (SiO 2 ) to be volatized as H 2 O, so that the native oxide layer is removed. Also, it is desirable that a temperature in the surface process be a temperature (e.g., 600 to 950 which can prevent a diffusion of dopants existing within the P-type n-channel doping layer 35 .
In the above-described surface process at the hydrogen atmosphere, fluorine (F) ions remained within the P-type n-channel doping layer 35 A after the recovery annealing process are additionally emitted as a type of HF. Meanwhile, in case where 30 BF + molecular ions are implanted into the P-type n-channel doping layer 35 , implanted fluorine ions are reduced to half the 49 BF 2 + molecular ions at the same implantation amount as the 49 BF 2 + molecular ions, so that it is much easier to remove the fluorine ions.
As a result, it is much effective to remove the fluorine ions by implementing the 30 BF + molecular ions having a relative smaller fluorine containing amount at a relatively larger implementing amount when forming the channel doping layer.
As shown in FIG. 5D, an epitaxial layer 36 is grown to a thickness of 5 nm to 30 nm on the semiconductor substrate 31 with no native oxide layer, preferably on the P-type n-channel doping layer 35 , using a selectively epitaxial growth (SEG).
As described above, as the P-type n-channel doping layer 35 is activated to the very shallow P-type n-channel doping layer 35 A that is chemically stabilized through the recovery annealing process, an SSR epi-channel structure with an SSR delta doping profile of which the loss and re-distribution of dopants is minimized is formed even during the surface process at the hydrogen atmosphere and the growth of the epitaxial layer 36 .
As shown in FIG. SE, a gate dielectric layer 37 is formed at a temperature of 650 to 750 on the SSR epi-channel structure, e.g., the epitaxial layer 36 disposed at a lower portion of the P-type n-channel doping layer 35 A. At this time, the temperature range for forming the gate dielectric layer 37 is relatively low so as to prevent a re-distribution and diffusion of dopants existing within the P-type n-channel doping layer 35 A.
For this, a low temperature oxide (LTO) layer formed at a low temperature, a silicon oxynitride layer, a high dielectric layer or a stack layer of oxide layer/high dielectric layer is used as the gate dielectric layer 37 . Because of the low thermal process for forming the gate dielectric layer 37 at a low temperature, the SSR doping profile can be maintained by preventing the re-distribution and the diffusion of dopants existing within the P-type n-channel doping layer 35 A.
For example, the low temperature oxide layer (i.e., a silicon thermal oxide layer) is formed at a temperature of 650 to 750 After forming the silicon thermal oxide layer at a temperature of 650 to 750, the silicon oxynitride layer is formed by carrying out a nitride plasma or ammonia plasma to the silicon thermal oxide layer. The high dielectric layer is formed by carrying out a deposition process at a temperature of 300 to 650 and then a furnace annealing process at a temperature of 400 to 700, or by carrying out a deposition process at a temperature of 300 to 650 and then a rapid thermal annealing process at a temperature of 600 to 800. In case where the high dielectric layer is used, a maximum temperature is limited to 300 to 700 when an annealing process is carried out so as to improve a layer quality of the dielectric layer.
Next, a conductive layer for a gate dielectric layer is deposited on the gate dielectric layer 37 and patterned the deposited conductive layer to thereby form a gate electrode 38 . Here, the conductive layer for forming the gate electrode 38 can be a polysilicon layer, a stack layer of polysilicon layer/metal layer, or a stack layer of polysilicon layer/silicide layer.
Then, using an additional photoresist mask (not shown) and the gate electrode 38 as an ion implantation mask, a large implantation amount of N-type dopants is implanted at a low energy to thereby form an N-type source/drain extension region 39 . At this time, the N-type dopants used to form the N-type source/drain extension region 39 are phosphorus (P) or arsenic (As).
Sequentially, after depositing an insulating layer for spacers on an entire surface containing the gate electrode 38 , the insulating layer for spacers is etched back to form spacers 40 contacted with sidewalls of the gate electrode 38 . Here, the spacers use a nitride layer or an oxide layer.
Then, using the additional photoresist mask, the gate electrode 38 and the spacers 40 as an ion implantation mask, a large implantation amount of N-type dopants is implanted to form an N-type source/drain region 41 that is electrically connected to the N-type source/drain extension region 39 . At this time, the N-type source/drain region 41 has a deeper ion implantation depth than the N-type source/drain extension region 39 .
As shown in FIG. 5F, an activation annealing process is carried out so as to electrically activate the dopants existing within the N-type source/drain region 41 and the N-type source/drain extension region 39 . At this time, the activation annealing process is carried out at a predetermined temperature which simultaneously inhibits the P-type n-channel doping layer 35 A from being diffused and the junction depths of the N-type source/drain region 41 and the N-type source/drain extension region 39 from being deepened.
Preferably, the activation annealing process is selected from the group consisting of a rapid thermal annealing (RTA) process of 600 to 1000, a furnace annealing process of 300 to 750, a spike rapid thermal annealing (SRTA) process of 600 to 1100, and a combination thereof.
Meanwhile, if the process of forming the gate electrode 38 and the N-type source/drain region 41 is carried out through a low temperature process having a low thermal budget, the SSR epi-channel structure in which the diffusion of dopants is inhibited can be maintained.
In the above embodiment, the P-type n-channel doping layer 35 A also acts as a punch stop layer for preventing a short channel effect. In addition, a junction capacitance and a junction leakage current with respect to an NP junction are reduced by forming a maximum doping depth of the P-type n-channel doping layer 35 A shallower than that of the N-type source/drain region 41 .
FIGS. 6A to 6 F are cross-sectional diagrams illustrating a method for fabricating a CMOSFET in accordance with a second embodiment of the present invention.
As shown in FIG. 6A, a field oxide layer 52 for device isolation is formed on a predetermined portion of a semiconductor substrate 51 using a shallow trench isolation (STI) process or a local oxidation of silicon (LOCOS) process. Then, a photoresist is coated on the semiconductor substrate 51 and patterned using exposure and development processes to thereby form a first mask 53 for exposing a region (hereinafter, referred to as a “PMOS region”) in which a PMOSFET is to be formed.
Then, N-type dopants such as phosphorus (P) are implanted into the semiconductor substrate 51 exposed by the first mask 53 to thereby form a deep N-type well 54 . N-type dopants are sequentially implanted to form an N-type field stop layer 55 shallower than the N-type well 54 .
Then, N-type dopants are implanted at an energy lower than an ion implantation energy for forming the N-type field stop layer 55 to there form a shallow N-type p-channel doping layer 56 of which a depth is 10 nm to 50 nm from a surface of the semiconductor substrate 51 . At this time, phosphorus (P) or arsenic (As) is used as the N-type dopants.
As shown in FIG. 6B, after removing the first mask 53 , a photoresist is again coated on the semiconductor substrate 51 and patterned using exposure and development processes to thereby form a second mask 57 for exposing a region (hereinafter, referred to as a “NMOS region”) in which a NMOSFET is to be formed.
Then, P-type dopants are implanted into the semiconductor substrate 51 exposed by the second mask 57 to thereby form a deep P-type well 58 . P-type dopants are sequentially implanted to form a P-type field stop layer 59 shallower than the P-type well 54 . At this time, boron (B) is used as the P-type dopants.
Next, molecular ions of fluorine compounds such as 49 BF 2 + or 30 BF + are implanted to thereby form a shallow P-type n-channel doping layer 60 of which a depth is 10 nm to 50 nm from the surface of the semiconductor substrate 51 .
As shown in FIG. 6C, after removing the second mask 57 , a recovery annealing process is carried out. The recovery annealing process recovers a crystal defect in the surface of the semiconductor substrate 51 , which is caused by an ion bombardment in the ion implantation for forming the N-type p-channel doping layer 56 and the P-type n-channel doping layer 60 . Also, the recovery annealing process allows the dopants implanted into the N-type p-channel doping layer 56 and the P-type n-channel doping layer 60 to be stably combined with adjacent silicon atoms within the crystals and also emits fluorine (F) ions implanted into the P-type n-channel doping layer 60 to an exterior.
For the recovery annealing process, a rapid thermal annealing (RTA) process or a spike rapid thermal annealing (SRTA) process is carried out at a temperature of below 1414 (a melting point of silicon), which can recover the crystal defect, in order to prevent a diffusion of dopants implanted into the N-type p-channel doping layer 56 and the P-type n-channel doping layer 60 . Preferably, the rapid thermal annealing (RTA) process is carried out at a temperature of 600 to 1050 and the spike rapid thermal annealing (SRTA) process is carried out at a temperature of 600 to 1100.
As described above, through the recovery annealing process, the N-type p-channel doping layer 56 and the P-type n-channel doping layer 60 are improved as a layer with no crystal defect by stably combining the implanted dopants with the silicon ions of the semiconductor substrate 51 . In particular, in the P-type n-channel doping layer 60 , fluorine (F) ions are emitted during the annealing process and the boron (B) ions are stably combined with the silicon (Si) ions.
As a result, after the recovery annealing process, the N-type p-channel doping layer 56 and the P-type n-channel doping layer 35 are activated as a very shallow N-type p-channel doping layer 56 A and a very shallow P-type n-channel doping layer 60 A, which are chemically stable.
As shown in FIG. 6D, after the recovery annealing process, a surface process is carried out at a hydrogen atmosphere in order to remove a native oxide layer (not shown) formed on the N-type p-channel doping layer 56 A and the P-type n-channel doping layer 60 A, which have no crystal defect, during the recovery annealing process. At this time, if the surface process is carried out at the hydrogen atmosphere, the hydrogen (H 2 ) is reacted with the native oxide-layer (SiO 2 ) to be volatized as H 2 O, so that the native oxide layer is removed. In addition, fluorine (F) ions remained within the P-type n-channel doping layer 60 A even after the recovery annealing process are additionally emitted.
As shown in FIG. 6E, epitaxial layers 61 and 62 are simultaneously grown to a thickness of 5 nm to 30 nm on the N-type p-channel doping layer 56 A and the P-type n-channel doping layer 60 A, which have no native oxide layer, using a selectively epitaxial growth (SEG).
As described above, as the N-type p-channel doping layer 56 and the P-type n-channel doping layer 60 are activated to the very shallow N-type p-channel doping layer 56 A and the very shallow P-type n-channel doping layer 60 A chemically stabilized through the recovery annealing process, an SSR epi-channel structure with an SSR delta doping profile in which loss and re-distribution of dopants in the NMOS region and the PMOS region is minimized is formed even during the surface process at the hydrogen atmosphere and the growth of the epitaxial layers 61 and 62 .
As shown in FIG. 6F, a gate dielectric layer 63 is formed at a temperature of 650 to 750 on the SSR epi-channel structure, e.g., the N-type p-channel doping layer 56 A and the P-type n-channel doping layer 60 A. At this time, the temperature range for forming the gate dielectric layer 63 is relatively low so as to inhibit a diffusion of dopants existing within the P-type n-channel doping layer 60 A.
For this, a low temperature oxide (LTO) layer, a silicon oxynitride layer, a high dielectric layer or a stack layer of oxide layer/high dielectric layer is used as the gate dielectric layer 63 . Because of the low thermal process of forming the gate dielectric layer 63 at a low temperature, the SSR doping profile can be maintained by preventing the re-distribution and the diffusion of dopants existing within the N-type p-channel doping layer 56 A and the P-type n-channel doping layer 60 A.
For example, the silicon thermal oxide layer is formed at a temperature of 650 to 750. After forming the silicon thermal oxide layer at a temperature of 650 to 750, the silicon oxynitride layer is formed by carrying out a nitride plasma or ammonia plasma to the silicon thermal oxide layer. The high dielectric layer is formed by carrying out a deposition process at a temperature of 300 to 650 and then a furnace annealing process at a temperature of 400 to 700, or by carrying out a deposition process at a temperature of 300 to 650 and then a rapid thermal annealing process at a temperature of 600 to 800. In case where the high dielectric layer is used, a maximum temperature is limited to 300 to 700 when an annealing process is carried out so as to improve a layer quality of the dielectric layer.
Next, a conductive layer for a gate dielectric layer is deposited on the gate dielectric layer 63 and patterned the deposited conductive layer to thereby form a gate electrode 64 . Then, with respect to the PMOS region and the NMOS region, using additional photoresist mask (not shown) and the gate electrode 64 as respective ion implantation mask, a large implantation amount of P-type dopants is implanted into the PMOS region at a low energy to thereby form a P-type source/drain extension region 65 . A large implantation amount of N-type dopant is implanted into the NMOS region at a low energy to thereby form an N-type source/drain extension-region 66 .
Here, the conductive layer for forming the gate electrode 64 can be a polysilicon layer, a stack layer of polysilicon layer/metal layer, or a stack layer of polysilicon layer/silicide layer. In addition, the N-type dopants used to form the N-type source/drain extension region 66 are phosphorus (P) or arsenic (As), and the P-type dopants used to form the P-type source/drain extension region 65 are boron (B), BF 2 , or boron compound ions containing boron.
Sequentially, after depositing an insulating layer for spacers on an entire surface containing the gate electrode 64 , the insulating layer for spacers is etched back to form spacers 67 contacted with sidewalls of the gate electrode 64 . Here, the spacers use a nitride layer, an oxide layer or a combination of nitride layer and an oxide layer.
Then, using the additional photoresist mask, the gate electrode 64 and the spacers 67 as an ion implantation mask, a large implantation amount of P-type dopants (boron or boron compound) is implanted into, the PMOS region to form a P-type source/drain region 68 that is electrically connected to the P-type source/drain extension region 65 .
In addition, using the additional photoresist mask, the gate electrode 64 and the spacers 67 as an ion implantation mask, a large implantation amount of N-type dopants (phosphorus or arsenic) is implanted into the NMOS region to form an N-type source/drain region 69 that is electrically connected to the P-type source/drain extension region 66 .
At this time, the N-type source/drain region 69 and the P-type source/drain region 68 have ion implantation depths deeper than the N-type source/drain extension region 66 and the P-type source/drain extension region 65 , respectively.
Then, an activation annealing process is carried out so as to electrically activate the dopants implanted into the N-type source/drain region 69 , the N-type source/drain extension region 66 , the P-type source/drain region 68 and the P-type source/drain extension region 65 .
At this time, the activation annealing process is carried out at a predetermined temperature which simultaneously inhibits the P-type source/drain region 68 and the P-type source/drain extension region 65 from being deepened.
That reason is because that the P-type source/drain region 68 and the P-type source/drain extension region- 65 have severer diffusion change than the N-type source/drain region 69 and the N-type source/drain extension-region 66 .
Preferably, the activation annealing process is selected from the group consisting of a rapid thermal annealing (RTA) process of 600 to 1000, a furnace annealing process of 300 to 750, a spike rapid thermal annealing (SRTA) process of 600 to 1100, and a combination thereof.
Meanwhile, if the processes of forming the gate electrode 64 , the P-type source/drain extension region 65 , the N-type source/drain extension region 66 , the P-type source/drain region 68 and the P-type source/drain region 69 are carried out through a low temperature process having a low thermal budget, the SSR epi-channel structure in which the diffusion of dopants is inhibited can be maintained.
In the above-described second embodiment, the N-type p-channel doping layer 56 A and the P-type n-channel doping layer 60 A also act as a punch stop layer for preventing a short channel effect. In addition, a junction capacitance and a junction leakage current with respect to a PN junction and an NP junction are reduced by forming respective maximum doping depths of the N-type p-channel doping layer 56 B and the P-type n-channel doping layer 60 A shallower than those of the P-type source/drain region 68 and the N-type source/drain region 69 .
FIG. 7 is a cross-sectional diagram of a CMOSFET in accordance with a third embodiment of the present invention. The CMOSFET of FIG. 7 has the same structure as the second embodiment except for a first N-type punch stop layer 70 , a second N-type punch stop layer 72 , a first P-type punch stop layer 71 and a second P-type punch stop layer 73 . Hereinafter, the same reference numerals as FIG. 6F are used in FIG. 7, and a detailed description about the same parts will be omitted.
In the same manner as the second embodiment, an epi-channel structure is formed on a PMOS region. The epi-channel includes a first N-type punch stop layer 70 formed by implanting phosphorus or arsenic ions and an-epitaxial layer 61 grown on the first N-type punch stop layer 70 . Meanwhile, an epi-channel structure is formed on an NMOS region. The epi-channel includes a first P-type punch stop layer 71 formed by implanting fluorine compound ions and an epitaxial layer 62 grown on the first P-type punch stop layer 71 .
Then, a second N-type punch stop layer 72 and a second P-type punch stop layer 73 are formed on lower portions of a P-type source/drain extension region 65 and an N-type source/drain extension region 66 , respectively. At this time, the second N-type punch stop layer 72 is formed by implanting N-type dopants (phosphorus or arsenic) equal to the first N-type punch stop layer 70 . Meanwhile, unlike the first P-type punch stop layer 71 formed by implanting boron-fluorine compound, the second P-type punch stop layer 73 is formed by implanting boron or boron compound.
Here, in order to respectively form the second N-type punch stop layer 72 and the second P-type punch stop layer 73 on the lower portions of the P-type source/drain extension region 65 and the N-type source/drain extension region 66 , an ion implantation process is carried out before forming the P-type source/drain region 68 and the N-type source/drain region 69 .
The first P-type punch stop layer 71 and the first N-type punch stop layer 70 act as a channel doping layer as well as a punch stop layer for preventing a short channel effect.
As a result, the CMOSFET in accordance with the third embodiment of the present invention has a dual punch stop layer structure. Compared with a single punch stop layer structure, the dual punch stop layer structure has an improved punch-through characteristic.
FIG. 8 is a cross-sectional diagram of a CMOSFET in accordance with a fourth embodiment of the present invention. The CMOSFET of FIG. 8 has the same structure as the third embodiment except for an elevated source/drain region. Hereinafter, the same reference numerals as FIG. 6F are used in FIG. 8, and a detailed description about the same parts will be omitted.
Referring to FIG. 8, in the same manner as the third embodiment, the CMOSFET in accordance with the fourth embodiment has a dual punch stop layer structure including a first N-type punch stop layer 70 and a second N-type punch stop layer 72 on a PMOS region, and a dual punch stop layer structure including a first P-type punch stop layer 71 and a second P-type punch stop layer 73 on an NMOS region. In addition, epitaxial layers are grown on the P-type source/drain region 68 and the N-type source/drain region 69 , respectively, to thereby form elevated source/drain regions 74 and 75 .
In the fourth embodiment of FIG. 8, a punch-through characteristic is improved by providing the dual punch stop layer through an ion implantation of boron-fluorine compound, and an increase in junction resistance of the source/drain is prevented by providing the elevated source/drain structure.
FIG. 9 is a cross-sectional diagram of a CMOSFET in accordance with a fifth embodiment of the present invention.
Referring to FIG. 9, an N-type well 83 and a P-type well 84 are formed within a semiconductor substrate 81 having a PMOS region and an NMOS region defined by a field oxide layer 82 , respectively. An N-type field stop layer, 85 is formed at a shallower portion than the N-type well 83 , and a P-type field stop layer 86 is formed at a shallower portion than the P-type well 84 .
A gate dielectric layer 87 , a polysilicon layer 88 , a metal layer 89 and a hard mask 90 are sequentially formed on the PMOS and NMOS regions of the semiconductor substrate 81 regions to thereby form a stack gate structure. Then, sidewall oxide layers 91 are formed on both sidewalls of the polysilicon layer 88 constituting the gate structure, respectively. Spacers 92 are formed on both sidewalls of the gate structure.
An epi-channel having an N-type p-channel doping layer 93 and an epitaxial layer 94 is formed below the gate dielectric layer 87 of the PMOS region, and an epi-channel having an P-type n-channel doping layer 95 and an epitaxial layer 96 is formed below the gate dielectric layer 87 of the NMOS region.
P-type source/drain extension regions 97 are formed on both sides of the epi-channel of PMOS region, and P-type source/drain region 98 contacted with the P-type source/drain extension region 97 are formed deeper in a junction depth than the P-type source/drain extension region 97 . N-type source/drain extension regions 99 are formed on both sides of the-epi-channel of NMOS region, and P-type source/drain region 100 contacted with the N-type source/drain extension region 99 are formed deeper in a junction depth than the N-type source/drain extension region 99 .
In FIG. 9, the metal layer 89 formed on the polysilicon layer 88 is adopted for resistivity and high-speed operation of the gate electrode and generally utilizes tungsten and tungsten silicide. In addition, a diffusion barrier layer can be inserted between the polysilicon layer 88 and the metal layer 89 .
The sidewall oxide layers 91 formed on both sidewalls of the polysilicon layer 88 is formed by oxidizing the polysilicon layer 88 using a gate re-oxidation process for recovering the gate dielectric layer 87 damaged during an etching process used to form the gate structure. As is well known, the gate re-oxidation process is carried out in order to improve reliability by recovering microtrench and loss of the gate dielectric layer 87 caused when etching the gate electrode, oxidizing an etching remaining material remained on a surface of the gate dielectric layer 87 , and increasing a thickness of the gate dielectric layer 87 formed at an edge of the gate electrode.
The gate re-oxidation process is carried out in order to prevent a breakdown of the SSR doping profile, which is caused by a diffusion of dopants implanted into the P-type n-channel doping layer 95 due to an excessive thermal process. At this time, if the thermal oxidation process such as the re-oxidation process is carried out using a rapid thermal oxidation (RTO), its maximum temperature is limited to 750 to 950. Meanwhile, if the thermal oxidation process is carried out using a furnace annealing process, its maximum temperature is limited to 650 to 800.
As described above, if the gate re-oxidation process is carried out using a low temperature process with a low thermal budget, an SSR epi-channel structure in which the diffusion of dopants is inhibited can be maintained.
In the fifth embodiment of FIG. 9, the N-type p-channel doping layer 93 and the P-type n-channel doping layer 95 also act as a punch stop layer for preventing a short channel effect In addition, a junction capacitance and a junction leakage current with respect to a PN junction and an NP junction are reduced by forming respective maximum doping depths of the N-type p-channel doping layer 93 and the P-type n-channel doping layer 95 shallower than those of the P-type source/drain region 98 and the N-type source/drain region 100 .
FIG. 10 is a cross-sectional diagram of a CMOSFET in accordance with a sixth embodiment of the present invention.
The CMOSFET of FIG. 10 has a dual punch stop layer structure including a first N-type punch stop layer 93 and a second N-type punch stop layer 101 on a PMOS region, a dual punch stop layer structure including a first P-type punch stop layer 95 and a second P-type punch stop layer 102 on an NMOS region. The other structure is the same as the CMOSFET of FIG. 9 .
FIG. 11 is a cross-sectional diagram of a CMOSFET in accordance with a seventh embodiment of the present invention.
The CMOSFET of FIG. 11 has a dual punch stop layer structure including a first N-type punch stop layer 93 and a second N-type punch stop layer 101 on a PMOS region, a dual punch stop layer structure including a first P-type punch stop layer 95 and a second P-type punch stop layer 102 on an NMOS region. In addition, epitaxial layers are grown on the P-type source/drain region 98 and the N-type source/drain region 100 , respectively, to thereby form elevated source/drain regions 101 and 104 . The other structure is the same as the CMOSFETs of FIGS. 9 and 10.
In fabricating the NMOSFET and CMOSFET in accordance with the first to seventh embodiments of the present invention, in order to prevent the SSR doping profile from being broken down due to the diffusion of dopants within the channel, doping layer, which is caused by the excessive thermal processes during the following process performed after forming the SSR epi-channel structure, the maximum temperature in the following rapid annealing process is limited to 600 to 1000. In addition, the maximum temperature in the following spike rapid annealing process is limited to 600 to 1100 and the maximum temperature in the following furnace annealing process is limited to 300 to 750.
Meanwhile, although the semiconductor devices having the source/drain extension regions are described in the first to fifth embodiments of the present invention, the present invention is also applicable to a semiconductor device having a lightly doped drain (LDD) structure.
FIG. 12 is a graph illustrating a boron concentration distribution of the SSR epi-channel in which 49 BF 2 + ions are implanted into the channel region. FIG. 12 shows a result after completing all the thermal processes required to fabricate the semiconductor device, such as a gate oxidation and a spike thermal annealing process after forming the source/drain. A horizontal axis represents a depth within the substrate and a vertical axis represents a boron concentration. A curve PS is a result obtained by implanting 49 BF 2 + ions at a doze of 2{overscore (7)}10 13 atoms/cm 3 and an acceleration energy of 5 keV, and a curve P 6 is a result obtained by implanting 49 BF 2 + ions at a doze of 2{overscore (7)}10 13 atoms/cm 3 and an acceleration energy of 10 keV.
Referring to FIG. 12, a peak value of the concentration is positioned at about 30 nm in the implantation of 49 BF 2 + ions, and the boron concentration is rapidly reduced at a deeper position.
The curves PS and P 6 have different reduction profiles from each other. The curve PS has narrower boron diffusion and the peak value of the curve PS is higher than that of the curve P 6 .
Since the present invention can easily implement the ultra-shallow SSR channel structure with a narrow width of the delta doping profile, it is possible to implement a high speed device by reducing the junction capacitance of devices of sub 100 nm grade.
In addition, since productivity is improved compared with the SSR doping method using a low-energy boron ion implantation, a high performance device can be fabricated at a low cost. The present invention can prevent a variation of threshold voltage due to a random dopant induced (RDI) and a short channel effect of a sub 10 nm gate length at the same time, thereby improving the yield of the device.
The dopant concentration of the channel surface area can be reduced to {fraction (1/100)} or more compared with the maximum concentration of the channel doping layer, thereby improving a surface mobility and a driving current characteristic.
Further, since the ultra-shallow SSR channel structure is easily implemented, it is easy to implement the low-voltage is device with a low threshold voltage and the low power consumption device.
While the present invention has been described with respect to certain preferred embodiments only, other modifications and variation may be made without departing from the spirit and scope of the present invention as set forth in the following claims. | This invention relates to a method for fabricating a semiconductor device with the epi-channel structure, which is adapted to overcome an available energy limitation and to improve the productivity by providing the method of SSR epi Channel doping by boron-fluoride compound ion implantation without using ultra low energy ion implantation and a method for fabricating the semiconductive device with epi-channel structure adapted to prevent the crystal defects caused by the epitaxial growth on ion bombarded and fluorinated channel doping layer. The method for forming the epi-channel of a semiconductor device includes the steps of: forming a channel doping layer below a surface of a semiconductive substrate by implanting boron-fluoride compound ions containing boron; performing an annealing process to remove fluorine ions, injected during above ion implantation, within the channel doping layer; performing the surface treatment process to remove the native oxide layer formed on the surface of the channel doping layer and simultaneously to remove remaining fluorine ions within the channel doping layer; and growing epitaxial layer on the channel doping layer using the selective epitaxial growth method. | 7 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims priority under 35 USC 119(e) to U.S. provisional Application Ser. No. 61/404,363, filed on Oct. 1, 2010, and which is incorporated herein by reference.
TECHNICAL FIELD
[0002] This disclosure relates generally to decoration for lockers. More specifically, this disclosure relates to perforated wallpaper for use decorating in lockers.
BACKGROUND
[0003] Lockers are often provided in schools, hospitals, gyms, factories, ski lodges, and other institutions for users to store books, belongings and other materials. The lockers are typically identical from locker to locker. Users often desire to decorate or otherwise personalize their lockers.
SUMMARY
[0004] This disclosure provides a system, apparatus and method for wallpaper for use in lockers.
[0005] A wallpaper panel for use in a locker is provided. The wallpaper panel includes a decoration on a first face of the wallpaper panel, and a plurality of perforations configured to allow removal of a portion of the wallpaper panel to accommodate a fixture on a surface of the locker.
[0006] A system is also provided. The system includes a plurality of magnets, at least some of the magnets including covers. The system also includes a plurality of wallpaper panels. At least one wallpaper panel includes a decoration on a first face of the wallpaper panel, a plurality of perforations configured to allow removal of a portion of the wallpaper panel to accommodate a fixture on a surface of the locker. An appearance characteristic of at least one of the covers is based on the decoration of at least one of the wallpaper panels.
[0007] In one embodiment, magnets are configured to affix the wallpaper panels to corresponding surfaces of the locker.
[0008] Other technical features may be readily apparent to one skilled in the art from the following figures, descriptions, and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0009] For a more complete understanding of the present disclosure, and the advantages thereof, reference is now made to the following descriptions taken in conjunction with the accompanying drawings, wherein like numbers designate like objects, and in which:
[0010] FIG. 1 depicts a locker of the type typically provided in a school, hospital, gym, factory, or other institution;
[0011] FIGS. 2A through 2C illustrate panels of locker wallpaper according to this disclosure;
[0012] FIGS. 3A through 3C illustrate a first embodiment of reverse faces of the panels of FIGS. 2A through 2C according to this disclosure;
[0013] FIGS. 4A through 4C illustrate a second embodiment of reverse faces of the panels of FIGS. 2A through 2C according to this disclosure;
[0014] FIGS. 5A through 5C illustrate a third embodiment of reverse faces of the panels of FIGS. 2A through 2C according to this disclosure; and
[0015] FIG. 6 illustrates a magnet 600 that may be used to hold the wallpaper panels to the inside surfaces of the user's locker, according to this disclosure.
DETAILED DESCRIPTION
[0016] The various embodiments used to describe the principles of the present invention in this patent document are by way of illustration only and should not be construed in any way to limit the scope of the invention. Those skilled in the art will understand that the principles of the invention may be implemented in any type of suitably arranged device or system.
[0017] FIG. 1 depicts a locker 100 of the type typically provided in a school, hospital, gym, factory, or other institution. Two lockers of the type shown in FIG. 1 may be stacked one above the other. The locker 100 includes a door 102 . The door 102 includes a latch mechanism 104 and louvers 106 . The locker further includes two side panels 108 (the interior of one side panel is not visible in FIG. 1 ) and a back panel 112 . One or both of the side panels 108 include a hook 110 . The back panel 112 includes a hook 114 .
[0018] While the lockers in an institution are typically identical among themselves, lockers purchased from different manufacturers or different locker product lines from a single manufacturer may be different from each other. Such differences may include the dimensions of a locker, as well as the number, size, location, and/or shape of interior fixtures such as latch mechanisms, hooks, and louvers. Furthermore, a locker manufacturer may provide alternative or additional interior fixtures.
[0019] FIGS. 2A through 2C illustrate panels of locker wallpaper according to this disclosure. In FIG. 2A , a first wallpaper panel 200 includes a portion 202 outlined by perforations. Some or all of the portion 202 may be removed to leave an opening for the latch mechanism 104 , allowing the remainder of the panel 200 to lie flat against the inside surface of the locker door 102 . The perforations permit the removal of a desired sub-portion of the portion 202 without requiring the use of a knife or other tool.
[0020] The panel 200 has dimensions selected to fit on the inside surface of a locker door. Typically, the size of the panel 200 is selected to fit the largest locker likely to be encountered by a user. As will be described in more detail with reference to FIGS. 3A-3C , 4 A- 4 C and 5 A- 5 C, the user may cut the panel 200 to fit into a smaller locker.
[0021] As seen on the left side of the portion 202 , a boundary of the portion 202 may be formed by a single line of perforations. As seen on the top and bottom of the portion 202 , boundaries may be formed by two or more lines of perforations. Such multiple lines of perforations allow the panel 200 to be adapted to locker doors of different manufacturers and/or product lines. A user may select the perforations that produce an opening having a suitable size and location for a configuration of a latch mechanism of the user's locker. The user may then “punch out” the selected portion(s) of the panel 200 to form the desired opening.
[0022] A decoration 204 may be printed or otherwise transferred onto the panel 200 . The decoration 204 may be a pattern, design, drawing, picture, photograph, slogan, name, or other graphical device that a manufacturer of the panel 200 may select in order to appeal to purchasers of locker wallpaper according to the disclosure. The decoration 204 may be a texture, flocking, or other treatment of the surface of the panel 200 .
[0023] In FIG. 2B , a second wallpaper panel 220 includes a portion 222 outlined by perforations. The panel 220 has dimensions selected to fit on the inside surface of a back panel of the largest locker likely to be encountered by a user. The portion 222 includes a plurality of rectangular sub-portions outlined by lines of perforations. One or more rectangular sub-portions of the portion 222 may be removed to produce an opening having a suitable size and location for a configuration of a hook or other fixture on a back panel of the user's locker.
[0024] A decoration 224 may appear on the wallpaper panel 220 . The decoration 224 may be identical to the decoration 204 or may be selected to be complementary to the decoration 204 .
[0025] In FIG. 2C , a third wallpaper panel 240 includes a portion 242 outlined by perforations. The panel 240 has dimensions selected to fit on the inside surface of a side panel of the largest locker likely to be encountered by a user. The portion 242 includes a plurality of rectangular sub-portions outlined by lines of perforations. One or more rectangular sub-portions of the portion 242 may be removed to produce an opening having a suitable size and location for a configuration of a hook or other fixture on a side panel of the user's locker.
[0026] A decoration 244 may appear on the wallpaper panel 240 . The decoration 244 may be identical to the decorations 204 and 224 or may be selected to be complementary to one or both the decorations 204 and/or 224 .
[0027] Typically, one panel 200 , one panel 220 and two panels 240 are packaged together for sale. However, individual panels may be provided as replacements or to permit the user to “mix and match” the decorations 204 , 224 and 244 .
[0028] While the portions 222 and 242 are interior to the wallpaper panels 220 and 240 , respectively, it will be understood that, in other embodiments, additional or alternative portions of a wallpaper panel according to the disclosure may be perforated to adapt the panel to additional or alternative fixtures on the back panel of a locker. Furthermore, in still other embodiments, some or all of the portions may extend all the way to one or more sides of the wallpaper panel. Similarly, in other embodiments, the portion 202 of the panel 200 may be interior to the panel 200 or have any other suitable arrangement relative to the edges of the panel 200 .
[0029] While the portions 202 , 222 and 242 of panels 200 , 220 and 240 , respectively, have been described as outlined by lines of perforations, it will be understood that in other embodiments, lines may be printed on either face of the panels 200 , 220 and 240 , rather than being perforated. In such embodiments, a user may remove a desired sub-portion by cutting the wallpaper on or near the printed lines using a knife, scissors, or other tool.
[0030] FIGS. 3A through 3C illustrate a first embodiment of reverse faces of the panels 200 , 220 and 240 of FIGS. 2A through 2 C according to the disclosure. In FIG. 3A a face 300 of the panel 200 opposite the face seen in FIG. 2A is presented. Guide lines 302 , 304 and 306 are printed, scored, or otherwise transferred to the panel 200 . The guide line 302 is located on a vertical centerline of the panel 200 . The guide lines 304 and 306 are located symmetrically on opposite sides of the guide line 302 . Where the panel 200 is too large for a user's locker, the guide lines 304 and 306 assist the user in cutting equal amounts from each side of the panel 200 , so that a desired characteristic of the panel 200 is maintained after the cutting. For example, in this embodiment, the decoration 204 remains centered on the panel 200 after the cutting.
[0031] In FIG. 3B , a face 320 of the panel 220 opposite the side seen in FIG. 2B is presented. Guide lines 322 , 324 and 326 are printed, scored, or otherwise transferred to the panel 220 . The guide line 322 is located on a vertical centerline of the panel 220 . The guide lines 324 and 326 are located symmetrically on opposite sides of the guide line 322 to assist the user in cutting equal amounts from each side of the panel 220 , so that the decoration 224 remains centered on the panel 220 after cutting.
[0032] In FIG. 3C , a face 340 of the panel 240 opposite the side seen in FIG. 2C is presented. Guide lines 342 , 344 and 346 are printed, scored, or otherwise transferred to the panel 240 . The guide line 342 is located on a vertical centerline of the panel 240 . The guide lines 344 and 346 are located symmetrically on opposite sides of the guide line 342 to assist the user in cutting equal amounts from each side of the panel 240 , so that the decoration 244 remains centered on the panel 240 after cutting.
[0033] While the guide lines of FIGS. 3A-3C are features printed onto the faces 300 , 320 and 340 of the panels 200 , 220 and 240 , in other embodiments, those guide lines may be features such as perforations, to enable the user to reduce the width of the panel without requiring the use of a knife, scissors, or other tool. In still other embodiments, the guide lines may be features that are scored into the faces 300 , 320 and 340 . Also, while only vertical guide lines are shown in FIGS. 3A-3C , in other embodiments horizontal guide lines may be included additionally or alternatively.
[0034] FIGS. 4A through 4C illustrate a second embodiment of reverse faces 400 , 420 and 440 of the panels 200 , 220 and 240 , respectively, of FIGS. 2A through 2C according to the disclosure. Grids 404 , 424 and 444 are printed on the faces 400 , 420 and 440 , respectively. Lines 402 , 422 and 442 of the grids 404 , 424 and 444 , respectively, are located on vertical centerlines of the faces 400 , 420 and 440 . The vertical and horizontal lines of the grids 404 , 424 and 444 assist a user in trimming the panels 200 , 220 and 240 to a desired size, while maintaining a desired characteristic of the panel after the cutting. For example, in this embodiment, the lines assist a user in keeping the edges of the panel straight and parallel.
[0035] FIGS. 5A through 5C illustrate a third embodiment of reverse faces 500 , 520 and 540 of the panels 200 , 220 and 240 , respectively, of FIGS. 2A through 2C according to the disclosure. In FIG. 5A , guide lines groups 502 , 504 , 506 and 508 are printed on the face 500 . In combination, a guide line from each of the groups 502 , 504 , 506 and 508 outline the boundary of a door for a particular locker manufacturer or product line. The lines representing the outline of a first manufacturer's door may be printed with a first dot pattern. The lines representing the outline of a second manufacturer's door may be printed with a second dot pattern. In this way, a user will be able to trim the panel 200 to fit a configuration of the door of his/her locker without the need for a trial and error fitting process.
[0036] Similarly, the faces 520 and 540 include guide line groups 522 / 524 / 526 and 542 / 544 / 546 , respectively. The guide lines of the faces 520 and 540 have dot patterns matching those of the face 500 , corresponding to the outlines of back panels and side panels of the same locker manufacturers and/or product lines. A list of manufacturers and product lines may be provided along with panels having the reverse faces 500 , 520 and 540 as a guide to the appropriate dot patterns for use in removing portions of the panels 200 , 220 and/or 240 to adapt to a configuration of a surface of the user's particular locker.
[0037] While horizontal guide lines are shown only along the bottom edges of the faces 520 and 540 , it will be understood that, in other embodiments, horizontal guide lines may additionally or alternatively be printed along the top edges of the faces 520 and 540 . For the horizontal and vertical guide lines of FIGS. 5A-5C , individual lines may be placed nearer or farther from their respective edges so that, after trimming, the “punch out” portions of the resulting wallpaper panels are located appropriately for internal fixtures of the user's locker manufacturer or product line.
[0038] FIG. 6 illustrates a magnet 600 that may be used to hold the wallpaper panels to the inside surfaces of the user's locker, according to this disclosure. A permanent magnet 602 is covered partially or completely by a cover 604 . The cover 604 may have a color, shape, design, or other appearance characteristic that is selected based on one or more of the decorations 204 , 224 and/or 244 of the panels 200 , 220 and 240 , respectively. For example, a color of the cover 604 may match or complement a color of one or more of the decorations 204 , 224 and/or 244 . Or, a shape of the cover 604 may be selected to match or complement a shape in one or more of the decorations 204 , 224 and/or 244 .
[0039] A plurality of magnets 600 may be used to attach a panel to the locker. The style(s) of the covers 604 in the plurality of magnets 600 may be the same or may differ from some or all of the other covers 604 . The plurality of magnets 600 may be packaged with some or all of the panels 200 , 220 and 240 , or may be provided separately, to allow the user to “mix and match” styles of the covers 604 with the decorations 204 , 224 and/or 244 of the panels 200 , 220 and 240 .
[0040] Note that while the above description has described particular details of example wallpaper panels according to the disclosure, these details are for illustration only. Other techniques could be used to produce locker wallpaper panels according to the disclosure. In one example, the panel 220 may be combined with two of the panels 240 (one on each side) into a single panel that would cover both side walls and the back wall of the user's locker.
[0041] It may be advantageous to set forth definitions of certain words and phrases used throughout this patent document. The terms “include” and “comprise,” as well as derivatives thereof, mean inclusion without limitation. The term “or” is inclusive, meaning and/or. The phrases “associated with” and “associated therewith,” as well as derivatives thereof, mean to include, be included within, interconnect with, contain, be contained within, connect to or with, couple to or with, be communicable with, cooperate with, interleave, juxtapose, be proximate to, be bound to or with, have, have a property of, or the like.
[0042] While this disclosure has described certain embodiments and generally associated methods, alterations and permutations of these embodiments and methods will be apparent to those skilled in the art. Accordingly, the above description of example embodiments does not define or constrain this disclosure. Other changes, substitutions, and alterations are also possible without departing from the spirit and scope of this disclosure, as defined by the following claims. | An apparatus and system for locker wallpaper panels include perforations and features for adapting the panels to selected locker configurations. The system includes magnets that are configured to affix the wallpaper panels to corresponding surfaces of the locker. | 8 |
BACKGROUND OF THE INVENTION
The invention refers to a fan with a driving dog and a fan wheel, to a method for assembling the fan wheel, and to a device for implementing the method.
A fan with a fan mounting with a dynamic unbalance weight is known from international patent application WO03/040570 A1. The described axial fan has a hub region for connecting the axial fan to a drive shaft of an electric drive, wherein the axial fan is statically balanced by means of a balance weight. A flexible connection is formed in the hub region between the axial fan and the drive shaft of an electric drive.
The occurrence of unbalance in a fan constitutes a problem particularly in the case of high-speed fans.
SUMMARY OF THE INVENTION
The object of the invention is to provide a fan, a method for assembling a fan, and a device for implementing the method, wherein a reduction of the unbalance of the fan can be achieved.
One advantage of the fan is that the driving dog and/or the fan wheel has or have a plurality of contact surfaces, wherein the contact surfaces have different height positions with regard to a center axis of the driving dog or of the fan wheel, and wherein the driving dog butts against the fan wheel by a fixed number of contact surfaces so that the unbalance, especially the dynamic unbalance, is reduced. Therefore, a two-plane unbalance can be reduced.
The method according to the invention for assembling the fan wheel with the driving dog has the advantage that an optimized height position between driving dog and fan wheel is created by means of a plurality of contact surfaces which have different height positions with regard to a center plane of the driving dog and/or to a center plane of the fan wheel. For this, different positions, i.e. different pairings of contact surfaces between driving dog and fan wheel are set, a level for the unbalance is measured, and the driving dog is fixedly connected to the fan wheel in the position in which the lowest unbalance occurs. Therefore, by means of the provided contact surfaces at different heights, an inclined position of the fan wheel with regard to a rotational axis or an unbalance, particularly a dynamic unbalance, of the fan wheel can be reduced.
The device according to the invention has the advantage that provision is made for a fixing bolt which fixes the fan wheel and the driving dog symmetrically in relation to each other, that provision is made for pressing-on means with which the fan can be pressed onto the driving dog in different angular positions. In this way, the method for determining an optimized angular position can be implemented without a screw fastening of the driving dog to the fan wheel being necessary.
Depending upon the selected embodiment, at least two contact surfaces of the driving dog have different height positions with regard to a center plane of the driving dog, wherein the contact surfaces of the fan wheel are arranged in one height position with regard to a center plane of the fan wheel.
In a further embodiment, the contact surfaces of the fan wheel are arranged in at least two different height positions with regard to a center plane of the fan wheel, wherein the contact surfaces of the driving dog are arranged at one height position with regard to the center axis of the driving dog.
Depending upon the selected embodiment, both the contact surfaces of the fan wheel and the contact surfaces of the driving dog can be arranged at at least two different height positions with regard to the corresponding center planes.
In a further embodiment, the driving dog and/or the fan wheel has or have groups of contact surfaces, wherein the groups have fixed angular spacings with regard to a center of the fan wheel. Each group has a plurality of contact surfaces, wherein the contact surfaces of a group are arranged in a row with fixed angular spacings. The contact surfaces of a group are arranged at a fixed radial distance from the middle of the fan wheel. In this way, provision is made for a large number of systematically arranged contact surfaces which allow a simple and quick selection of the contact angle between the fan wheel and the driving dog.
In a further embodiment, the contact surfaces of a group are arranged at at least two different height positions with regard to the center plane of the driving dog or the center plane of the fan wheel.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a schematic view of a fan,
FIG. 2 shows a cross section through a part of the driving dog and of the fan wheel,
FIG. 3 shows a plan view of a driving dog,
FIG. 4 shows a section F 1 through a driving dog,
FIG. 5 shows a section F 2 through the driving dog,
FIG. 6 shows a plan view of a fan wheel,
FIG. 7 shows a schematic view of the driving dog and of the fan wheel in a first angular position,
FIG. 8 shows a schematic view in a second angular position,
FIG. 9 shows a schematic view in a third angular position,
FIG. 10 schematically shows a finishing device for assembling the fan wheel on the driving dog,
FIG. 11 shows a partial cross section through the finishing device.
DETAILED DESCRIPTION
FIG. 1 shows in a schematic view a fan 1 with a drive 2 which has a drive shaft 3 . The drive shaft 3 is connected to a driving dog 4 in the form of a disk. The driving dog 4 may also be of a three-legged design or have any other form. The driving dog 4 is connected to the drive shaft 3 in a rotation-resistant manner at least in one rotational direction. A fan wheel 5 is fastened on a front side of the driving dog 4 . For example, the driving dog 4 has a central opening through which the drive shaft 3 is guided. The driving dog 4 can be connected to the drive shaft 3 via a press fit. Moreover, the fan wheel 5 can also have a central opening 20 into which the drive shaft 3 protrudes. In this way, both the driving dog 4 and the fan wheel 5 are aligned axially on a rotational axis which corresponds to the drive shaft.
Depending upon the selected embodiment, however, only the driving dog 4 may be connected directly to the drive shaft 3 . For fastening the fan wheel 5 on the driving dog 4 , provision is made for fastening means 6 , for example in the form of screws. Other types of fastening means, however, such as adhesive means, can also be used in order to connect the fan wheel 5 to the driving dog 4 .
The fan wheel 5 has a fan hub 6 , on the outer side of which fan vanes 7 are formed.
For avoiding unbalance, it is necessary for the fan wheel 5 to be fastened on the driving dog 4 in a plane perpendicular to the longitudinal axis of the drive shaft 3 . For this, the driving dog 4 and the fan wheel 5 have defined contact surfaces.
In a further embodiment, the fan wheel 5 is fastened for example by a driving dog 4 on a rotor of a brushless external-rotor motor. In this case, the fan wheel 5 can also be fastened directly on the rotor.
FIG. 2 shows in a schematic view a cross section through the drive shaft 3 , the driving dog 4 and the fan wheel 5 in the region of a contact region. A contact block 8 is formed on an outer side of the driving dog 4 . An additional contact block 9 , which is part of the fan wheel 5 , bears on the contact block 8 . The contact block 8 has a first contact surface 10 which bears on an additional contact surface 11 of the additional contact block 9 . The contact surface 10 , as seen in the axial direction of the drive shaft 3 , is arranged at a first height h 1 with regard to a center plane 12 of the driving dog 4 . The additional contact surface 11 of the additional contact block 9 is arranged at a further height position h 2 with regard to a second center plane 13 of the fan wheel 5 . The center planes are arranged perpendicularly to the drive shaft 3 .
For a reliable alignment, provision is made for three contact regions with a defined contact surface 10 of the driving dog 4 in each case and an associated defined additional contact surface 11 of the fan wheel 5 . The three contact regions are spaced apart in this case preferably by an angle of 120° and lie on a circular line with regard to a center of the driving dog or of the fan wheel. Depending upon the selected embodiment, provision may also be made for more than three contact regions. Moreover, instead of a contact block 8 , provision may also be made for an opening with a contact surface. In a further embodiment, instead of the additional contact block 9 an additional opening may also be formed in the fan wheel 5 , in which an additional contact surface 11 is formed.
FIG. 3 shows a schematic view of an outer side of the driving dog 4 which is associated with the fan hub 6 in the assembled state. On the front side 14 , the driving dog 4 has three groups 15 , 16 , 17 of contact surfaces 10 . In the depicted exemplary embodiment, each group has four contact surfaces 10 . The contact surfaces 10 of the groups 15 , 16 , 17 are arranged on a circular ring with constant radius to the middle 21 of the driving dog. Moreover, the contact surfaces of a group have the same angular distance from each other in each case. Furthermore, the first, second, third and fourth contact surface of a group in each case, as seen in the counterclockwise direction, are arranged at a 120° angle to the first, second, third and fourth contact surface in each case,
In the depicted exemplary embodiment, the first contact surface in each case has a height position z 0 with regard to the surface of the outer side of the driving dog 4 . In the first group 15 , the second, third and fourth contact surface B 1 , B 2 , B 3 , following in the clockwise direction, have a height position zn according to the following formula: Bn: =zn=z 0 +n×a, wherein n can be a number from 1 to 10 and the parameter a can have a value of between 0.01 and 0.1 mm. Instead of the value range of 0.01 mm and 0.1 mm, the parameter a can also lie within a range of between 0.01 and 1 mm. The contact surfaces are identified by n in the sequence in the counterclockwise direction. The contact surface B 1 has the height position z 1 =z 0 +1×a=z 0 +a.
In the second group 16 , the second, third and fourth contact surface C 1 , C 2 , C 3 have the following height position zn with regard to the surface of the outer side of the driving dog 4 : Cn=zn=z 0 −(n×a). In the same way, the second, third and fourth contact surface C 1 , C 2 , C 3 , as seen in the counterclockwise direction, of the third group 17 have a height position which is determined by means of the index n and the following formula: Cn has the height position zn=z 0 (n×a) in relation to the surface of the outer side of the driving dog 4 .
The contact surface C 1 therefore has the height position z 1 =z 0 (1×a)=z 0 −a. This means that the height positions of the contact surfaces of the first group 15 increase in steps in the counterclockwise direction. The height positions of the contact surfaces of the second and third groups 16 , 17 decrease in steps in the counterclockwise direction. Depending upon the selected embodiment, the contact surfaces of the second and third groups 16 , 17 also have different height positions. In particular, the second or third group 16 , 17 can also have contact surfaces with height positions corresponding to those of the first group 15 .
FIG. 4 shows a section F 1 through a contact surface A which is arranged on a contact block 8 at a height position z 0 with regard to the surface of the driving dog 4 .
FIG. 5 shows a cross section through a contact surface C 1 which is arranged on a contact block 8 at a height position z 1 =z 0 (1×a)=z 0 −a with regard to the surface of the driving dog 4 .
FIG. 6 shows a schematic view of the fan wheel 5 with six additional contact surfaces 11 , wherein only the fan hub 6 is shown. Depending upon the selected embodiment, provision can also be made for only three additional contact surfaces 11 or multiples of three additional contact surfaces 11 , wherein three additional contact surfaces 11 have an angular spacing of 120° in each case. In addition to the depicted exemplary embodiment, the six additional contact surfaces 11 of the fan wheel 5 in each case have an angular spacing of 60° from each other. The additional contact surfaces 11 may be formed on additional contact blocks 9 or in openings of the fan wheel 5 . The depth of the openings in this case, however, must be less than the height of the lowest contact block 8 of the driving dog 4 .
In the view of the driving dog 4 of FIG. 3 , the three first contact surfaces 10 represent a first bearing position, the second contact surfaces B 1 , C 1 , C 1 of the first, second and third groups 15 , 16 , 17 in each case represent a second bearing position, the third contact surfaces B 2 , C 2 , C 2 in each case of the first, second and third groups 15 , 16 , 17 represent a third bearing position and the fourth contact surfaces B 3 , C 3 , C 3 in each case of the first, second and third groups 15 , 16 , 17 in each case represent a fourth bearing position by which the driving dog 4 can be brought to bear on the corresponding additional contact surfaces 11 of the fan wheel 5 .
Since in the selected exemplary embodiment the additional contact surfaces 11 are arranged at a standard height position and the contact surfaces of the first group 15 of the driving dog 4 increase in height position in the counterclockwise direction, wherein the contact surfaces of the second and third groups 16 and 17 decrease in height position in the counterclockwise direction, different inclined positions can be set regardless of whether which contact surface of the first, second and third groups 15 , 16 , 17 are used for bearing on the fan wheel 5 .
FIG. 7 shows a schematic view of an assembled fan, in which only the driving dog 4 and the fan hub 6 of the fan wheel 5 are shown. In FIG. 7 , the fan wheel 5 is fastened on the driving dog 4 in a first angular position, wherein the fan wheel 5 has three additional contact surfaces 11 which bear on the three first contact surfaces A of the groups 15 , 16 , 17 of the driving dog 4 . In this position, the fan wheel 5 is aligned parallel to the driving dog 4 since the additional contact surfaces 11 of the fan wheel 5 have the same height position with regard to a center plane of the fan wheel 5 and, moreover, the first contact surfaces A of the groups 15 , 16 , 17 of the driving dog 4 also have the same height position with regard to the center plane of the driving dog 4 .
FIG. 8 shows a driving dog 4 and a fan wheel 5 of a fan 1 , wherein the fan wheel 5 bears on the driving dog 4 in a second position and is fastened to the driving dog. In the second position, the three additional contact surfaces 11 of the fan wheel 5 are arranged on the second contact surfaces 10 , B 1 , C 1 , C 1 in each case, as seen in the counterclockwise direction, of the first, second and third groups 15 , 16 , 17 of the driving dog 4 . The height position of the second contact surface B 1 of the first group 15 of the driving dog 4 has the following height position: z 0 +1×a=0+a. The height position of the second contact surface C 1 of the second group 16 of the driving dog 4 has the height position z 0 (1×a)=z 0 a. Similarly, the second contact surface of the third group 16 of the driving dog 4 has the height position z 0 −(1×a)=z 0 a.
Therefore, a calculated inclined position between the driving dog 4 and the fan wheel 5 is set.
FIG. 9 shows a schematic view of a fan wheel 5 and of a driving dog 4 of the fan 1 in a third angular position. In the third angular position, the additional contact surfaces 11 of the fan wheel 5 bear on the fourth contact surfaces B 3 , C 3 , C 3 in each case, as seen in the counterclockwise direction, of the first, second and third groups 15 , 16 , 17 of the driving dog 4 . In this third position, the fan wheel 5 is arranged in a manner in which it is tilted to an even greater degree in relation to the driving dog 4 than in the second position. This ensues because the height position of the fourth contact surface B 3 of the first group 15 has the following height position: z 0 +(3×a)=z 0 +3a. Moreover, the fourth contact surfaces of the second and third groups 16 , 17 of the driving dog 4 have the following height position: z 0 −(3×a)=z 0 −3a. Therefore, the distance between the fan wheel 5 and the driving dog 4 in the region of the contact surfaces of the second and third groups is less by the distance 6 a than in the region of the fourth contact surface of the first group 15 .
Therefore, by means of the depicted embodiments four angular positions which are inclined to a different degree can be created when assembling the driving dog with the fan wheel 5 . A further variation, moreover, can be achieved by provision being made for not only three additional contact surfaces 11 on the fan wheel 5 but, for example, for six additional contact surfaces, as is shown in FIG. 6 . Therefore, not only three additional contact surfaces 11 but six additional contact surfaces 11 are made available in order to set an optimum angular position between the fan wheel 5 and the driving dog 4 in which a preferred, preferably minimal unbalance exists.
The optimum angular position between the driving dog 4 and the fan wheel 5 is determined by all possible angular positions being tested and a resulting unbalance being measured. Final fastening of the fan wheel 5 on the driving dog 4 is then undertaken in the angular position in which the lowest unbalance is encountered. In this way, by means of a plurality of groups of contact surfaces with different height positions a calculated inclined position between the fan wheel 5 and the driving dog 4 can be set, with which an existing unbalance is compensated.
In the depicted exemplary embodiment, the groups of contact surfaces 10 , arranged at different heights, are arranged on the driving dog 4 . Depending upon the selected embodiment, the same groups of contact surfaces 10 with different height positions can also be formed on the fan wheel 5 . In this way, the possibility of the combination of angular positions is additionally increased. Moreover, instead of the depicted exemplary embodiment, the groups of additional contact surfaces 10 , arranged at different heights, can be arranged on the fan wheel 5 and the driving dog 4 can have contact surfaces 10 with the same height position, as is shown in the example of the fan wheel 5 of FIG. 4 .
FIG. 10 shows an arrangement for testing and for assembling a driving dog 4 with a fan wheel 5 . Thus, the arrangement has a baseplate with a centering bolt 23 which is guided through the center opening of the driving dog 4 and the center opening of the fan wheel 5 . By means of three hydraulically operable fixing bolts 24 , the fan wheel 5 is then pressed against the driving dog 4 , wherein the fan wheel 5 bears by additional contact surfaces 11 on contact surfaces 10 of the driving dog 4 in a first angular position. Then, for example an axial eccentricity measurement is carried out in order to determine by means of a measuring system 28 the unbalance on the fixed angular position. For this, the arrangement with the fan wheel 5 is set in rotation and by means of the measuring system 28 the unbalance of the arrangement consisting of driving dog and fan wheel is determined by an axial eccentricity measurement. In a further angular position, the fan wheel 5 is then pressed against the driving dog 4 by means of the fixing bolt and an unbalance measured once again. In this way, the angular position in which the lowest unbalance occurs is determined. In this angular position, the fan wheel 5 is then fixedly connected to the driving dog 4 , especially screw-fastened. For this, for example auto screw connections 25 are used.
The fixing bolt 24 may be operated by means of a hydraulic cylinder, for example.
FIG. 11 shows a cross section through a corresponding arrangement of a baseplate 29 with a centering bolt 23 and with fixing bolts 24 with hydraulic cylinders 26 , with which a friction-resistant connection can be achieved between the driving dog 4 and the fan wheel 5 for measuring the unbalance. | The present invention relates to a fan, to a method, and to a device for assembling the fan. The fan has an axis of rotation, which is connected to a dog, wherein the dog is connected to a fan wheel, wherein the dog, in a first number of contact surfaces, is in contact with additional contact surfaces of the fan wheel, wherein the dog and/or the fan wheel have more than the first number of contact surfaces and/or additional contact surfaces, wherein at least two contact surfaces have different height positions with respect to a central axis of the dog and/or the fan wheel. | 8 |
CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is a Continuation of U.S. patent application Ser. No. 14/837,367, filed Aug. 27, 2015, now allowed, which is a Continuation of U.S. patent application Ser. No. 12/713,088, filed Feb. 25, 2010, now U.S. Pat. No. 9,144,471, which is a Continuation-In-Part of U.S. patent application Ser. No. 12/503,151, filed on Jul. 15, 2009, now abandoned, which is a Continuation-In-Part of U.S. patent application Ser. No. 11/862,628, filed on Sep. 27, 2007, now U.S. Pat. No. 8,123,523, which is a Continuation-In-Part of U.S. patent application Ser. No. 11/682,927, filed on Mar. 7, 2007, now abandoned, which is a Continuation-In-Part of U.S. patent application Ser. No. 11/189,193, filed on Jul. 26, 2005, now U.S. Pat. No. 7,422,433, all of which are incorporated herein by reference in their entirety. This application is related to U.S. patent application Ser. No. 12/712,993, filed on Feb. 25, 2010, now U.S. Pat. No. 8,834,159, entitled “ADJUSTABLE ANGLE PROPHY ANGLE ADAPTER,” and U.S. patent application Ser. No. 12/713,070, filed on Feb. 25, 2010, now U.S. Pat. No. 8,459,992, entitled “PROPHY ANGLE AND ADAPTER WITH LATCH,” all of which are incorporated herein by reference in their entirety.
BACKGROUND OF THE INVENTION
Field of the Invention
[0002] The disclosure relates generally to dental instruments and, more specifically, to prophy angles and adapters for use with prophy angles.
Description of the Related Art
[0003] Dental prophylaxis angles, generally referred to as “prophy angles,” are commonly used dental instruments for providing rotation for dental tools such as brushes, prophy cups, or other receptacles used in cleaning/polishing teeth. Referring to FIGS. 17 and 18 , a prophy angle 10 typically includes a housing 16 having a neck 18 and a head portion 14 extending at approximately a 90° angle to the neck 18 , which increases the ability of a dentist to reach various surfaces of the teeth of a patient. A drive shaft or prophy rotating member 12 can be located within the housing 16 and attached to a driven gear 20 in the head of the prophy angle. Prophy angles 10 are generally affixed to an adapter or hand piece (not shown), which connects the prophy angle to a drive source (not shown), thereby enabling a rotating motion of the prophy rotating member 12 and driven gear 20 of the prophy angle and any affixed dental tool.
[0004] Prophy angles 10 are commonly manufactured from lightweight plastic to make them disposable, thereby increasing overall sterility in the dental environment. An issue associated with making the prophy angles 10 , and their constituent elements, such as the prophy rotating member 12 , from plastic is the ability of the hand piece to engage the prophy rotating member 12 without slipping and to engage the prophy rotating member 12 without excessive damage to the prophy rotating member 12 . Another issue associated with the use of prophy angles 10 is the widespread use of many different and incompatible types of couplings between the drive source and the hand piece and between the hand piece and the prophy angle 10 . Yet another issue associated with the use of prophy angles 10 is the number of adapters needed to provide different orientations.
BRIEF SUMMARY OF THE INVENTION
[0005] A dental system comprises a dental prophy angle and an adjustable angle adapter. The prophy angle includes a housing and a guard with an inner surface of the guard being concave. The adapter is configured to drive the prophy angle and the adapter includes a body, a nose, and an outer joint. The nose is configured to receive a portion of a prophy angle. The body is adjustably connected to the nose. The outer joint includes a ball portion connected to the nose and a ball receiver positioned on the body. The ball receiver comprises a first portion and a second portion, the first portion is coupled to a first end of the body and the second portion is attachable to the first portion. The nose is rotatable relative to the body into at least a first configuration and a second configuration. The concave inner surface of the guard engages a convex outer surface of the ball receiver.
[0006] In certain aspects, the guard has a greatest outer diameter 10% larger than a greatest outer diameter of the housing, and in other aspects, the guard has a greatest outer diameter 20% larger than a greatest outer diameter of the housing.
[0007] In additional aspects, in the first configuration, the shaft and the rotating member share a common rotational axis. In the second configuration, a rotational axis of the shaft is at a non-zero degree angle to a rotational axis of the rotating member. The nose is rotatable relative to the body from between zero degrees to about twenty degrees. The guard includes an inner surface having a spherical radius that substantially matches a spherical radius of an outer surface of the ball receiver. The inner surface of the guard includes a plurality of inwardly-extending ribs. A seal is formed between the inner surface of the guard and the outer surface of the ball receiver. Also, a motor integral with the body can be provided.
[0008] Additional aspects of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. The aspects of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the appended claims. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory only and are not restrictive of the invention, as claimed.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
[0009] The accompanying drawings, which are incorporated in and constitute part of this specification, illustrate embodiments of the invention and together with the description, serve to explain the principles of the invention. The embodiments illustrated herein are presently preferred, it being understood, however, that the invention is not limited to the precise arrangements and instrumentalities shown, wherein:
[0010] FIGS. 1A, 1B, and 1C are perspective views of a prophy angle with an integrated guard detached and attached to an adjustable angle adapter, in accordance with the inventive arrangements;
[0011] FIG. 2 is an exploded, side view of an adjustable angle adapter, in accordance with the inventive arrangement;
[0012] FIG. 3 is an exploded, side view of an adjustable angle adapter, in accordance with another embodiment of the inventive arrangement;
[0013] FIGS. 4A and 4B are, respective, a side and detail view of a guard, in accordance with the inventive arrangement;
[0014] FIG. 5 is a perspective view of a ball portion and nose of the adjustable angle adapter, in accordance with the inventive arrangement;
[0015] FIG. 6 is a perspective view of a ball receiver and body of the adjustable angle adapter, in accordance with the inventive arrangement;
[0016] FIGS. 7A and 7B are perspective views of the adjustable angle adapter, respectively, in contra-style and straight orientations;
[0017] FIG. 8 is a detail, side cross-sectional view of an outer joint of the adjustable angle adapter, in accordance with the inventive arrangement;
[0018] FIGS. 9A and 9B are side cross-sectional views of the adjustable angle adapter, respectively, in contra-style and straight orientations;
[0019] FIG. 10 is a perspective view of a prophy angle with latching mechanism, in accordance with the inventive arrangements;
[0020] FIG. 11 is a side cross-sectional view of the latching mechanism;
[0021] FIGS. 12A-12D are, respectively, cross-sectional view of the prophy angle with latching mechanism and nose of the adapter in a disassembled, partially-assembled, fully-assembled and latched, and full-assembled and unlatched configurations;
[0022] FIGS. 13A-13C are, respectively, a front perspective view, a front plan view, and a side cross-sectional view of a collet in accordance with the inventive arrangements;
[0023] FIGS. 14A-14D are, respectively, a perspective view of a receiver, a perspective view of the receiver and a second pin, a perspective view of a first pin and the second pin, and a perspective view of the first pin and the second pin position within a head of a yoke and pin joint in accordance with the inventive arrangements;
[0024] FIGS. 15A and 15B are, respectively, side and top views of the head of the multi-axis rotation joint and a shaft to which the head is connected;
[0025] FIG. 16 is a side view of an adapter with an integral micromotor;
[0026] FIG. 17 is a perspective view of a prophy angle according to the prior art;
[0027] FIG. 18 is a side cross-sectional view of the prophy angle according to the prior art; and
[0028] FIGS. 19A and 19B are, respectively, exploded and assembled cross-sectional views of a shaft-less prophy angle and adapter.
DETAILED DESCRIPTION OF THE INVENTION
[0029] Referring to FIGS. 1A-1C , the guard 380 may be integrated into the housing 16 of the prophy angle 10 . Further, an inner surface 382 of the guard 380 can be concave. In this way, the guard 380 can mate with the convex outer surface 327 of the ball receiver of the adapter 100 . The adapter 100 can further include a body 110 and a nose 112 . Since common practice is to treat the prophy angle 10 as a disposable item that is replaced each time the adapter 100 is used with a new patient, the guard 380 can also be replaced each time the prophy angle 10 is replaced. Since the guard 380 acts as a seal between the nose 112 and the ball receiver, each instance the prophy angle 10 is replaced, a new seal is provided between the nose 112 and the ball receiver.
[0030] As illustrated, the guard 380 extends from a receiving end of the housing 16 . Additionally, the guard 380 has a greatest outer diameter is larger than a greatest outer diameter of the housing 16 . Further, the inner surface 382 of the guard 380 may include a plurality of inwardly-extending ribs 384 , as illustrated in FIG. 1B , or the inner surface 382 of the guard 380 may be smooth, i.e. not including ribs, as shown in FIG. 1A . In certain aspects, the greatest outer diameter of the guard 380 is 10% greater than the greatest outer diameter larger than a greatest outer diameter of the housing 16 . In other aspects, the greatest outer diameter of the guard 380 is 20% greater than the greatest outer diameter larger than a greatest outer diameter of the housing 16 .
[0031] FIG. 2 illustrates an exemplar adjustable angle adapter 100 for use with a prophy angle. The adapter 100 includes a body and a nose 112 . The adapter 100 includes a shaft 118 , which is adjustably connected to a nose rotating member, such as a collet 200 , for receiving a prophy rotating member of the prophy angle. The nose 112 includes a first bore for receiving the prophy rotating member and, in certain configurations, a portion of the shaft 118 and/or collet 200 . In certain aspects, the adapter 100 includes a multi-axis rotation joint 400 that connects the shaft 118 to the nose rotating member (e.g., collet 200 ). Additionally, the adapter 100 includes an outer joint that connects the body to the nose 112 .
[0032] As is known in the art, many different types of drive sources exist and these different drive sources have different configurations for coupling with a rotating member, such as the shaft 118 . In this regard, the present adapter 100 is not limited as to the type and configuration of coupler 126 that couples with the drive source. However, in certain aspects of the adapter 100 , the coupler 126 is an E-type coupler. Other types of couplers/connection devices have been previously described with regard to the nose 112 .
[0033] The shaft 118 is rotated by the drive source, which is connected to a coupler 126 positioned on one end of the shaft 118 , which drives a collet 200 connected on another end of the shaft 118 . In certain configurations of the adjustable angle adapter 100 , both the coupler 126 and the collet 200 rotate about a common rotational axis, RA. However, in other configurations of the adjustable angle adapter 100 , the coupler 126 and the collet 200 rotate about different rotational axes, RA 1 , RA 2 .
[0034] Many types of shafts 118 are capable of transmitting rotation from the coupler 126 to the collet 200 , and the present adjustable angle adapter 100 is not limited as to a particular type of shaft 118 so capable. As the rotational axis RA 2 of the shaft 118 may be at an angle to the rotational axis RA 1 of the collet 200 , a multi-axis rotation joint (see discussion with regard to FIGS. 14A-14C and 15A-15B ) is positioned between the collet 200 and the shaft 118 to transfer the rotation of the shaft 118 to the collet 200 .
[0035] Referring specifically to FIG. 3 , the nose and guard can have different configurations relative to one another. For example, in the upper configuration illustrated in FIG. 3 , the nose 112 U is inserted fully into the guard 380 U and subsequently mates with a neck 311 of a ball portion 310 . In the lower configuration, the nose 112 L mates with a perpendicular face of the guard 380 L. As can be readily envisaged, other configurations are possible. Although not limited in this manner, the assembly of an adapter 100 can include splitting the ball receiver 312 into two separate portions 317 , 319 , as illustrated in the bottom of FIG. 3 and, in part, in FIGS. 5 and 6 .
[0036] As shown in the bottom portion of FIG. 3 and FIGS. 5 and 6 , the first portion 317 is connected to the body 110 and the first portion 317 is attachable to the second portion 319 using, for example, mating threads. While the first portion 317 of the ball receiver 312 is separate from the second portion 319 of the ball receiver 312 , the ball portion 310 having a neck 311 is inserted into the cavity defined by the inner surface of the ball receiver 312 . The second portion 319 of the ball receiver 312 is then slid over the ball portion 310 and attached to the first portion 317 of the ball receiver 312 . In so doing, the body 110 is joined to the nose 112 at an outer joint.
[0037] It is further noted that multiple, different spherical surfaces between the dental prophy angle and the adapter share a common center point. For example, the following all share a common center point with each other: a convex spherical outer surface of a ball portion 310 that can mate with a concave spherical inner surface of a ball receiver 312 , as illustrated in FIGS. 5 and 6 ; as seen in FIG. 8 , a spherical convex outer surface 327 of the ball receiver 312 , which can mate with the spherical concave inner surface of a guard 380 ; and, a convex spherical outer surface of a multi-axis rotation joint 400 can mate with the concave spherical inner surface of a receiver 406 that is connected to a collet 200 , as shown in FIGS. 14A and 14D . It is further noted that there are additional spherical surfaces on non-rotating elements that share a common center point with the surfaces referenced above. For instance, there are two spherical surfaces that are associated with the drive mechanism that rotate on both RA 1 and RA 2 that share a common center point with the spherical surfaces referenced above.
[0038] In reference to FIGS. 4A and 4B , a guard 380 can be provided that creates a seal between the nose and the ball receiver. The guard 380 includes an inner surface 382 having a radius that substantially matches a radius of the outer surface of the ball receiver. Additionally, the guard 380 can include a sealing element 386 that engages the outer surface of the ball receiver to form a seal. This seal acts to prevent debris, during operation of the adapter, from entering the outer joint. As the nose pivots relative to the body, the sealing element 386 remains substantially in contact with the outer surface of the ball receiver to maintain the seal between the nose and the ball receiver.
[0039] By their very nature, seals tend to wear over time and/or use and become less effective. In certain aspects of the outer joint, the guard 380 can be considered a replaceable portion of the adapter 100 . Also, although not limited in this manner, the guard 380 can be formed from an easily-fashioned material, such as autoclavable plastic. The outer joint is not limited in the manner in which the guard 380 can be replaceable. For example, referring to FIG. 3 , the guard 380 U, 380 L may be removably attachable to the nose 112 U, 112 L, and the manner by which the guard 380 U, 380 L is removably attachable to the nose 112 U, 112 L is not limited. For example, the guard 380 U, 380 L may screw onto the nose 112 U, 112 L. Alternatively, one or more removable pins may be used to attach the guard 380 U, 380 L to the nose 112 U, 112 L. Additionally, the guard 380 U may screw onto the neck 311 of the ball portion 310 . In certain aspects, the guard 380 L floats between the nose 112 L and the ball receiver 327 .
[0040] In addition, the inner surface 382 of the guard 380 may include a plurality of inwardly-extending ribs 384 to engage the outer surface of the ball receiver. The ribs 384 provide a grabbing surface with which the guard 380 can prevent movement of the guard 380 relative to the ball receiver upon outside pressure being placed against the guard 380 , thereby preventing movement of the body relative to the nose. Although the ribs 384 are illustrated as being disposed on the guard 380 , the ribs 384 may be disposed on the outer surface of the ball receiver. Additionally, although the ribs 384 are illustrated as radiating from a center, the ribs 384 may be configured to constitute a plurality of concentric circles. In a different embodiment, the inner surface 382 of the guard 380 may be smooth, i.e. include no ribs (see FIG. 1A ).
[0041] Referring to FIGS. 7A and 7B , an embodiment of an outer joint 300 for an adapter 100 is illustrated. In this particular embodiment, the ball receiver is positioned on the body 110 , and the ball portion is positioned on the nose 112 . In addition, a guard 380 is coupled to the nose 112 . This embodiment of the outer joint 300 can also include a stop that defines a maximum angle that the body 110 can pivot relative to the nose 112 .
[0042] In further illustration of an adjustable angle adapter with a multi-axis rotation joint 400 and an outer joint 300 , FIG. 8 shows a portion of the nose 112 (e.g., the neck 311 of ball portion 310 ) will ultimately engage a portion of the body 110 (e.g., an angled surface 313 of the ball receiver 312 that extends from the inner surface 325 to the outer surface 327 of the ball receiver 312 ). Additionally, by angling the surface 313 , as opposed to having a face that is perpendicular to the inner surface 325 of the ball receiver 312 or the outer surface 327 of the ball receiver 312 , a greater proportion of outer surface 327 of the ball receiver 312 can be any contact with an inner surface of a guard 380 at any given angular configuration. In this configuration, upon the nose 112 engaging the body 110 , a maximum angle that the body 110 can pivot relative to the nose 112 can be defined. Additional and/or alternative configurations can also be used to define the maximum angle that the body 110 can pivot relative to the nose 112 . In one embodiment, at a particular angle of the body 110 relative to the nose 112 , the distal end of the guard 380 may engage a shoulder 362 in the outer surface 327 of the ball receiver 312 . In this manner, the maximum angle that the body 110 can pivot relative to the nose 112 can be defined. Further, although not limited in this manner, in certain aspects of the adapter, the multi axis rotation joint 400 and the outer joint 300 pivot about a common pivot point.
[0043] Although not limited in this manner, FIG. 8 further illustrates that the ball receiver 312 can be split into two separate portions 317 , 319 . The first portion 317 is connected to the body 110 and the second portion is attachable to the second portion 319 using, for example, mating threads. While the second portion 319 of the ball receiver 312 is separate from the first portion 317 of the ball receiver 312 , the ball portion 310 is inserted into the cavity defined by the inner surface 325 of the ball receiver 312 . The second portion 319 of the ball receiver 312 is then slid over the ball portion 310 and attached to the first portion 317 of the ball receiver 312 . In so doing, the body 110 is joined to the nose 112 at the outer joint 300 .
[0044] FIG. 8 further indicates that in certain aspects of an adapter, one or more drag devices 370 may be included within the outer joint 300 , the drag devices 370 act to increase the drag between the ball portion 310 and ball receiver 312 as the nose 112 pivots relative to the body 110 . By increasing the drag between the ball portion 310 and the ball receiver 312 , the nose 112 is less likely to pivot relative to the body 110 during use of the adapter and after the adjustment of the angle between the body 110 and the nose 112 . Additionally, although the drag device 370 is illustrated with respect to the additional embodiment, the adapter is not limited in this manner, and the drag device 370 can be employed in the previous embodiment.
[0045] Although a single drag device 370 is illustrated, more than a single drag device 370 can be employed. Also, if more than a single drag device 370 is employed, these drag devices can be positioned equidistant to one another. In certain aspects of the outer joint 300 , three drag devices 370 are provided and positioned 120 degrees apart.
[0046] Any type of drag device 370 capable of increasing the drag between the ball portion 310 and the ball receiver 312 as the nose 112 pivots relative to the body 110 is acceptable for use in the joint 300 . However, in certain aspects, the drag device 370 includes a plunger 372 and a biasing means (e.g., a spring 374 ) positioned within a channel of either the ball receiver 312 or the ball portion 310 . As illustrated, the drag device 370 is positioned within the ball portion 310 . In certain aspects of the drag device 370 , the outer surface of the plunger 372 substantially matches the outer radius of the ball portion 310 .
[0047] Referring to FIGS. 9A and 9B , an adapter 100 with an outer joint 300 is illustrated. It is noted that although the current illustrated adapter 100 includes a single joint, multiple joints can be provided. Here an adapter 100 can be adjusted from a configuration in which the nose 112 and body 110 share a common centerline (also referred to as a straight adapter, see FIG. 9B ) to a configuration in which the centerlines of the nose 112 and the body are at a non-zero degree angle to one another (also referred to as a contra-style or angled adapter, see FIG. 9A ). As illustrated in FIGS. 9A and 9 B, the ball receiver 312 is positioned on the body 110 , and the ball portion 310 is positioned on the nose 112 . However, in a different embodiment, in one aspect of the outer joint, the ball-shaped portion can be positioned on the body and the ball receiver can be positioned on the nose. This embodiment of the outer joint 300 can also include a stop that defines a maximum angle that the body 110 can pivot relative to the nose 112 . The adapter 100 also includes a shaft 118 , which is adjustably connected to a nose rotating member, such as a collet 200 , for receiving a prophy rotating member of the prophy angle. The nose 112 includes a first bore 114 for receiving the prophy rotating member and, in certain configurations, a portion of the shaft 118 and/or collet 200 . In certain aspects, the adapter 100 includes a multi-axis rotation joint 400 that connects the shaft 118 to the nose rotating member (e.g., collet 200 ). The multi-axis rotation joint 400 allows for the angle between the rotational axis RA 2 of the shaft 118 and the rotational axis RA 1 of the collet 200 to be varied. Thus, use of the multi-axis rotation joint 400 permits the adjustable angle adapter 100 to be adjusted while the shaft 118 and collet 200 are rotating. To further enable the adjustable angle adapter 100 to be adjusted during the rotation of the shaft 118 and collet 200 , the nose 112 pivots relative to the body 100 about a point that is congruent with the intersection point between the rotational axes RA 1 , RA 2 of the collet 200 and shaft 118 . Additionally, the adapter 100 includes an outer joint 300 that connects the body 110 to the nose 112 .
[0048] In certain configurations, the outer joint 300 permits the nose 112 to pivot relative to the body 110 (or the body 110 to pivot relative to the nose 112 ). Specifically, the outer joint 300 can permit the nose 112 to pivot relative to the body 110 by at least 18 degrees. Additionally, the outer joint 300 permits the nose 112 to pivot related to the body 110 to multiple different angles between a straight configuration (i.e., 0 degrees) and a maximum-angle configuration (e.g. 18 degrees). In this manner, the adjustable angle adapter 100 provides greater flexibility to a user of the adapter 100 . Advantageously, this flexibility can reduce the number of different types of adapters 100 a particular user may require. In certain aspects, the maximum-angle configuration can be as high as 30 degrees. As referred to herein, the pivoting is about a pivot point at the intersection of a centerline of the body 110 and a centerline of the nose 112 . The centerline of the body 110 and the centerline of the nose 112 substantially correspond, respectively, to a rotational axis RA 2 of the shaft 118 and the rotational axis RA 1 of the nose rotating member (e.g., collet 200 ). As referred to herein, “to pivot” is defined as a change in the angle between the rotational axis RA 2 (or centerline of the body 110 ) of the shaft 118 and the rotational axis RA 1 (or centerline of the nose 112 ) of the nose rotating member (e.g., collet 200 ). In addition, the outer joint 300 can also permit the nose 112 to rotate relative to the body (or the body 110 to rotate relative to the nose 112 .) As the term is used herein, the rotation of the nose 112 and/or body 110 refers to the rotation of the nose 112 and/or body 110 about its own centerline/pivot axis. Additionally, the outer joint 300 can permit the nose 112 to both rotate and pivot relative to the body (or the body 110 rotate relative to the nose 112 ).
[0049] Further, as there are different drive sources with different configurations for coupling with a rotating member, such as the shaft 118 . In this regard, in one embodiment, the adapter 100 includes a coupler 126 , which is an E-type coupler. In addition, a guard 380 can be provided that creates a seal between the nose 112 and the ball receiver 312 . Although not limited in this manner, the engagement of the guard 380 and the ball receiver 312 can act to define a maximum angle that the body 110 can pivot relative to the nose 112 .
[0050] It is noted the outer portion of the nose 112 may be shaped to mate with the prophy angle. As is known in the art, many types of different types of prophy angles exist that have different mating profiles, and the present adapter 100 is not limited as to a particular shape of the nose 112 and as to a particular profile of prophy angle with which the nose 112 can mate. However, in a certain aspects of the adapter 100 , the nose 112 is configured as a doriot-style adapter. Depending upon the type of prophy angle, other types of connections devices include, but are not limited to, latch type, 3-ball chuck, attachment ring, push chuck, quick-connect collars, autochucks, E-type (i.e., ISO 3964), DIN 13940, ISO 1797, U-type, NSK type, and Midwest.
[0051] Now referring to FIGS. 10, 11, and 12A-12D , a prophy angle 10 with a latching mechanism 40 is illustrated. The latching mechanism 40 includes a latch element 49 , a male/female latch protrusion 42 , and a lever 44 that engages and/or disengages the male/female latch protrusion 42 . The nose 112 of the adapter also includes a female/male element 46 that is configured to engage the male/female protrusion 42 of the latching mechanism 40 in the prophy angle 10 . Although the latching mechanism 40 is illustrated with a shaft-less prophy angle 10 , the latching mechanism 40 may also be employed with a prophy angle having a prophy rotating member (i.e., shaft).
[0052] Although the latch protrusion 42 is illustrated as a male element and element 46 of the nose 112 as a female element, these configurations can be swapped. In operation, referring to FIG. 12B , as the prophy angle 10 is placed over the nose 112 , the nose 112 displaces the latch element 49 and, thus, the latch protrusion 42 from its resting orientation relative to the remainder of the prophy angle 10 . However, referring to FIG. 12C , as the prophy angle 10 is fully inserted onto the nose 112 , the latch protrusion 42 is released from its displaced orientation and is positioned within the female element 46 (e.g., a groove) in the nose 112 . In so doing, the latch protrusion 42 prevents removal of the prophy rotating member from collet.
[0053] Referring to FIG. 12D , to release the latching mechanism, the lever 44 is depressed (see down arrow), which acts to rotate the latch element 49 and the latch protrusion 42 about a pair of pivots 48 A, 48 B (as labeled in FIG. 10 ) and out of the groove 46 in the nose 112 (see up arrow). To permit depressing of the lever 44 , a depression 119 (as labeled in FIG. 12A, 12B ) is formed in the outer surface of the nose 112 proximate the groove 46 . Thus, as illustrated, movement of the lever 44 between a first position (not depressed) (e.g., FIG. 12C ) and a second position (depressed) (e.g., FIG. 12D ) moves the latch protrusion 42 between an engaged position and a disengaged position.
[0054] Referring again to FIG. 10 , although not limited to this particular configuration, each one of the pair of pivots 48 A, 48 B is defined by a pair of substantially parallel and opposing slots 51 , 53 within the housing. Also, a first one 51 of the pair of slots of the first pivot 48 A connects to a first one 51 of the pair of slots of the second pivot 48 B, and a second one 53 of the pair of slots of the first pivot 48 A connects to a second one 53 of the pair of slots of the second pivot 48 B. The latch mechanism 40 may be formed from the housing 16 of the prophy angle 16 . Although not limited to this particular configuration, the lever action of the latch mechanism 40 may be formed by including a pair of opposing U-shaped slots 51 , 53 within the housing 16 . Additionally, the latch protrusion 42 may be disposed within the bounds of the U-shaped slot within the housing 16 . As can be readily envisaged, the slots 51 , 53 are not limited to a U-shape. For example, one or both of the slots 51 , 53 could be V-shaped, rectangular-shaped, or shaped like a half moon.
[0055] FIGS. 13A-13C further illustrate the collet 200 . The collet 200 of the adapter is adapted to receive and hold the prophy rotating member 12 of the prophy angle 10 . In certain aspects of the adapter, the collet 200 is not limited in the manner in which the collet 200 receives and holds the prophy rotating member 12 , and any configuration of the collet 200 so capable is acceptable for use with the adapter. In certain aspects of the adapter, the collet 200 includes a plurality of extensions 210 a - 210 c for receiving the prophy rotating member 12 (see FIG. 13B ). The innermost portions of the extensions 210 a - 210 c define an inner collet bore 208 having a diameter slightly less than the diameter of the prophy rotating member 12 . In this manner, upon the prophy rotating member 12 being positioned within the inner collet bore 208 , an interference fit or friction grip exists between the plurality of extensions 210 a - 210 c and the prophy rotating member 12 . The interference fit allows the extensions 210 a - 210 c to hold onto the prophy rotating member 12 and to transfer rotation from the collet 200 to the prophy rotating member 12 . In certain aspects of the collet 200 , the innermost portions of the extensions 210 a - 210 c define an inner collet bore 208 having a fixed diameter.
[0056] As further illustrated in FIGS. 13A-13C , the outer edge of each extension 210 a - 210 c may also include a concave surface. The concave surfaces of the extensions 210 a - 210 c can define the outer circumference of the inner collet bore 208 of the collet 200 . These concave surfaces also mate with the outer surface of the prophy rotating member 12 to form the interference fit between the plurality of extensions 210 a - 210 c and the prophy rotating member 12 . Although not limited in this manner, the radius of the concave surfaces of the extensions 210 a - 210 c is substantially equal to the radius of the collet bore 208 . Although not limited in this manner, in certain aspects of the collet 200 , the concave surfaces define less than 20% of the circumference of the collet bore 208 .
[0057] Further, the collet 200 may also include longitudinal chamfers 202 on the extensions 210 a - 210 c . The chamfers may extend from a collet distal end 206 along each extension 210 a - 210 c and slope inwardly towards the rotational axis of the collet 200 . The longitudinal chamfers 202 provide a guide for receiving the prophy rotating member 12 . As the prophy rotating member 12 is moved into the collet 200 , the longitudinal chamfers 202 guide the prophy rotating member 12 toward the inner collet bore 208 . Although not limited in this manner, a face of the longitudinal chamfers 202 may be angled at about 60°±15° relative to the face of the distal end 206 of the collet 200 .
[0058] The manner in which the inner collet bore 208 is formed is not limited. For example, the inner collet bore 208 may be formed by drilling the collet 200 along its centerline. By forming the inner collet bore 208 in this manner, the concave surfaces at the outer edge of each extension 210 a - 210 c may also be formed. Also, the extensions 210 a - 210 c may be formed by drilling offset bores 204 a - 204 c , which have a centerline offset from the centerline of the collet 200 . Although the term “drilling” is used herein, other methodology used to form bores/holes is also acceptable.
[0059] Many types of joints are capable of transferring rotation from a first rotating member to a second rotating member, which is positioned off-axis from the first rotating member, and the present adjustable angle adapter is not limited as to a particular type of joint so capable. In a current aspect of the adapter, the multi-axis rotation joint is a yoke and joint., as illustrated in FIGS. 14A-14C and 15A-15B .
[0060] Referring to FIGS. 14A-14C and 15A-15B , elements of a multi-axis rotation joint are illustrated. In FIGS. 14A and 14B , the collet 200 is connected to a receiver 406 for receiving a head of the multi-axis rotation joint. Although shown connected to the collet 200 , the receiver 406 may be integral with the collet 200 . Alternatively, another member (not shown) may be positioned between the receiver 406 and the collet 200 . The use of a multi-axis rotation joint advantageously reduces back lash, which is inherent in many types of joints. The receiver 406 includes openings 408 into which a second pin 404 is positioned. Although the second pin 404 may rotate within the openings 408 of the receiver 406 , in a current aspect of the multi-axis rotation joint, the second pin 404 is positionally and rotationally fixed relative to the receiver 406 . In so doing, the second pin 404 is prevented from moving within the receiver 406 . Since the receiver 406 , and thus the ends of the second pin 404 , can rotate about the rotational axis of the collet 200 at very high speeds, any movement of the ends of the second pin 404 beyond the outer circumference of the receiver 406 may cause engagement between the ends of the second pin 404 and inner surfaces of the nose and/or the body of the adapter. This engagement may cause failure of or damage to the adapter and/or the multi-axis rotation joint.
[0061] The manner in which the second pin 404 is prevented from moving within the receiver 406 is not limited as to a particular technique or arrangement. For example, the second pin 404 can be attached to the receiver, for example, via welding or gluing. However, in a current aspect of the multi-axis rotation joint, the second pin 404 is sized slightly greater than the size of the openings 408 of the receiver 406 such that upon inserting the second pin 404 into openings 408 , an interference fit exists between the second pin 404 and the openings 408 .
[0062] Referring now to FIGS. 14C and 14D , the second pin 404 is positioned within an opening 403 of a first pin 402 , and the first pin 402 is positioned within a head. Further in FIG. 14D and in FIGS. 15A and 15B , the head 410 includes slots 414 through which the second pin 404 extends. As presently configured, the first pin 402 rotates within and relative to the head bore 412 of the head 410 about a rotational axis RA 4 , and the second pin 404 rotates within relative to the first pin 402 about a rotational axis RA 3 . The outside diameter of the second pin 404 is somewhat less than the inside diameter of the inside diameter of the opening 403 of the first pin 402 to form a close tolerance slip fit between the second pin 404 and the first pin 402 . Similar, the outside diameter of the first pin 402 is somewhat less than the inside diameter of the head bore 412 of the head 410 to form a close tolerance slip fit between the first pin 402 and the head bore 412 of the head 410 .
[0063] Although not limited as to a particular range of rotation or to the particular manner described herein, the first pin 402 , while within the head 410 , is limited in its range of rotation by the length of the slot 414 in the head 410 . As the length of the slot 414 increases, the range of the rotation of the first pin 402 within the head 410 is also increased. Conversely, upon the length of the slot 414 decreasing, the range of rotation of the first pin 402 within the head 410 is also decreased. The width of the slots 414 may be slightly less than the outside diameter of the second pin 404 to allow the second pin 404 to move from side-to-side within the slots 414 .
[0064] With regard to the range of rotation of the second pin 404 within the first pin 402 , the range of rotation is not necessarily limited when the first pin 402 is within the second pin 404 alone. However, upon the joint being fully assembled, the range of rotation of the second pin 404 within the first pin 402 may be limited to some degree by interference between the collet 200 and the shaft 118 . Although illustrated as the head 410 being connected to the shaft 118 and the receiver 406 being connected to the collet 200 , the multi-axis rotation joint is not limited in this manner. For example, the head 410 may be connected to the collet 200 , and the receiver 406 may be connected to the shaft 118 .
[0065] FIG. 16 illustrates an adjustable angle adapter 500 with an micromotor 528 that is integral with the body 510 of the adjustable angle adapter 500 . Upon using an integral micromotor 528 with the adjustable angle adapter 500 , the shaft may be directly connected to both the micromotor 528 and joint. Using micromotors to drive dental equipment is well known by those in the art, and any micromotor 528 so capable is acceptable for use with the adjustable angle adapter 500 . Examples of micromotors 528 include electrically-driven and pneumatically-driven motors. In the presently-illustrated adjustable angle adapter, the micromotor 528 is pneumatically driven.
[0066] Referring to FIGS. 19A and 19B , a shaft-less prophy angle 10 SL and an adapter 100 with an integrated drive shaft 350 is illustrated. With shaft-less prophy angles 10 SL, the shaft is an integral part of the nose 112 . Although illustrated with a non-adjustable adapter 100 , these concepts are also applicable to an adjustable adapter. The adapter 100 , directly or indirectly, provides the rotational movement to a gearing system of a rotor 20 of the prophy angle 10 . The adapter 100 includes a body 110 and a nose 112 . The adapter 100 includes a shaft 118 that is connected to a drive shaft 350 via a coupler 400 .
[0067] The shaft 118 is rotated by the drive source 450 . As is known in the art, many different types of drive sources 450 exist and these different drive sources 450 have different configurations for coupling with a rotating member, such as the shaft 118 . In this regard, the present adapter 100 is not limited as to drive source 450 for the adapter 100 . For example, the drive source 450 may be connectable to the adapter 100 . Alternatively, the drive source 450 may be integrated with the adapter 100 . Also, examples of drive sources 450 include electrically-driven and pneumatically-driven motors
[0068] In addition, the drive shaft 350 is a part of the adapter 100 . In other aspects, the drive shaft 350 is removably attachable to a collet within the adapter 100 . In so doing, the drive shaft 350 can be replaceable and/or cleaned. A slideable sleeve 460 may be positioned over the drive shaft 350 . The slideable sleeve 460 moves from an extended position ( FIG. 19A ), which conceals the gear 352 of the drive shaft 350 , to an retracted position ( FIG. 19B ), which reveals the gear of the drive shaft 350 . The slideable sleeve 460 is not limited in the manner in which the slideable sleeve 460 moves from the extended position to the retracted position and back again. The gear 352 is configured to engage the prophy angle 10 to drive rotor 20 . | A dental tool comprises a guard having a concave inner surface at one end and an adapter. The adapter comprising a nose, a monolithic ball portion having an integral neck, and a ball receiver comprising a convex outer surface and a concave inner surface, where the concave inner surface of the ball receiver engages a convex outer surface of the monolithic ball portion, the concave inner surface of the guard engages the convex outer surface of the ball receiver, and an opposite end of the guard rests upon the nose. | 0 |
FIELD OF THE INVENTION
The present invention relates to a 30 kDa protein termed Tp30, that is specific for cells that are programmed to die. The present invention also relates to the use of monoclonal antibodies specific for Tp30. The Tp30 protein and monoclonal antibodies thereto are useful in the detection and therapy of disorders wherein the natural regulation of cell death events is interrupted. Such disorders include cancer, bone degeneration, autoimmune diseases, neurodegenerative diseases, cardiovascular disorder, ischemia, HIV-associated illness and kidney malfunction.
BACKGROUND OF THE INVENTION
Cells, the basic unit of every organism, usually follow a precise program of life span in every tissue. Starting from the very beginning, each cell in an embryo is destined for a particular tissue. During development, each cell reproduces itself and multiplies in number, thus producing the mass needed for the creation of the tissue. However, during this process of multiplication, more cells may be produced than are needed. Consequently, nature has provided a suicidal process to eliminate these extra cells. This process, termed programmed cell death or apoptosis, involves the activation of unique genes whose functions are involved in the actual killing process of the cells themselves. However, there are also genes which can counteract these "killer" genes and protect those cells that are meant to live. The genes that are involved in the killing action are termed death genes, and those that are involved in survival are termed anti-death genes.
During adulthood, the programmed cell death process is tightly controlled for each tissue. For some tissues, in general those tissues composed of cells that are permanently growth-arrested, i.e. their cell mass cannot be replenished by further cell replication, programmed cell death must not occur. If it does, the cells that die are a permanent loss to the system. This is the case for cardiomyocytes, neuronal and muscle cells as loss of these cells results in functional degeneration and eventual failure of tissue functions in brain, heart or muscle. In contrast, if cellular units such as epithelial cells in the breast or uterus of postmenopausal women are no longer needed, there is an active program of tissue regression to get rid of these cells. If and when the programmed cell death involved in this regression is derailed, extra cell mass will accumulate, which in turn can lead to the formation of cancer. Similarly, in the haemopoietic cell system, the balance between those cells living and those cells scheduled to die must be precisely regulated in order to provide a healthy cell mass. Tilting the balance in favor of more living than dying cells results in hyperplasia, a beginning point leading to neoplasia and subsequent cancer development.
The health status of any given tissue is dependent upon the number of cells that are living and functional. Too many cells, resulting from failure of programmed cell death, may result in cancer development in some tissues. On the other hand, too few cells, resulting from overactive programmed cell death, may result in degeneration in tissue such as brain, muscle and heart. Therefore, the method of marking out the death events, in terms of frequency, number and rate of cells that are designated to die, is most critical in allowing clinicians, pathologists and researchers informative means of detection, diagnosis and treatment.
Several genes have been identified as related to programmed cell death. These genes may be separated into two categories: those of known class and those of novel class. Included in the known class are the oncogenes and anti-oncogenes, such as c-myc, c-ras, E1A and p53, and several growth factors and cytokines. Included in the novel class are ced3, ced4, ced9, inter-leukin converting enzyme (ICE), reaper, and members of the bcl2 family. The applicability of the known gene class will be less specific, and in particular confusing, as to oncogene usage, one must clarify whether the application is related to cell growth or cell death.
In the case of the novel class, ced3, ced4, ced9 and reaper are found only in lower organisms such as C. elegans, a needle worm and fruitfly, and are not found in man. bcl2 and its related genes are useful only to study cells that survive, since this gene functions as a survival factor to protect cells from dying. ICE is a mammalian analogue of ced3. Therefore, marking specific dying cell populations can only be performed at present in mammalian cells by ICE. So far, large quantities of high-quality antibodies to ICE are not available. In addition, information on ICE's presence in normal and diseased tissues is also absent. Consequently, there is a real need for the identification of a protein marker that is specific for cells programmed to die. Such a marker can be used as a tool to detect or treat diseases wherein the natural regulation of cell death events is interrupted.
SUMMARY OF THE INVENTION
The present invention relates to the identification of a 30 kDa protein, termed Tp30, that is specific for cells that are programmed to die. The Tp30 protein is a proteolytic product of terminin. Terminin is a 90 kDa cytoplasmic protein that is expressed in permanently growth arrested and terminally differentiated cells and can be used to distinguish between temporarily and permanently growth arrested cells. Terminin was identified by preparing a monoclonal antibody (Mab 1.2) that identifies senescence specific but not quiescence dependent antigens. When Mab 1.2 was identified it was found to recognize terminin Tp90 in growing and quiescent cells and a 60 Kd protein Tp60 in senescent cells. Tp60 is the proteolytic product of posttranslational modification of the Tp90 protein. Tp60 is the marker distinguishing between senescence and quiescence.
Recently it was determined that Mab 1.2 also recognizes a 30kDa protein (called terminin protein 30 or Tp30) in cells that are programmed to die. Tp30 (like Tp60) is a proteolytic product of Tp90. Therefore, not only can the presence of Tp30 be used as a marker for cell death commitment but also the ratio between Tp90 and Tp30 can be used as a quantitative index to denote the scope and frequency of programmed cell death in a given tissue.
The present invention thus provides the use of the Tp30 protein, the nucleic acid sequence coding for it and the monoclonal antibody that recognizes Tp30 (Mab 1.2) in the detection, or diagnosis or therapy of disorders where the natural regulation of cell death events is interrupted. In particular Tp30, nucleic acid sequences coding for it and Mab 1.2 can be used in the detection, diagnosis and therapy of cancer, bone degeneration, autoimmune diseases, neurodegenerative diseases, cardiovascular disorders, ischemia, HIV-associated illness, kidney malfunction, as well as other disorders where natural regulation of cell death events is interrupted. In particular, monoclonal antibodies to terminin protein Tp30 and terminin-like proteins may be used to define the pool size of dying cells in any given tissue. The invention also includes the use of nucleotide sequences coding for terminin and related genes, to detect the RNA such as mRNA and protein derived therefrom. Therefore, the monoclonal antibodies to terminin protein Tp30 and its related proteins, as well as the nucleotide sequences, can be used in a kit form for diagnostic purposes as well as assessment, in terms of scope and frequency of cell death in any biopsy tissues from either normal or disease conditions. These assessments of cell death incidents are necessary to determine disease staging, treatment regimen and the efficiency of either chemotherapeutic drug development or gene therapy. In addition, the monoclonal antibodies and nucleotide sequence to terminin, Tp30, and its related proteins can be used in a kit with a group of nonproliferation-specific markers such as statin, as a complete assessment of cell growth and survival status in any given tissues in terms of the size of the subpopulations of cells in growing (statin negative), nongrowing (statin positive), and dying (Tp30 positive) states.
The present invention can be carried out using various techniques known in the art. One example is the application of immunohistochemical studies with monoclonal antibodies to terminin protein Tp30 and its related proteins, on either biopsy or autopsy tissues. Another example is the application of labelling dying cells which are at different phases of the cell cycle in fluorocytometric studies. A third example is the application of immunoblotting techniques to examine the presence of Tp30 bands in the cell extracts of those tissues shown by immunohistochemical technique to be positive for the monoclonal antibody (Mab 1.2) to Tp30. A fourth example is the application of sequence-specific nucleotide probes to terminin protein, Tp30, to detect abnormality or normality of terminin protein Tp30 and its related genes in tissues of interest. Another example is the use of both monoclonal antibodies and nucleotide sequences to terminin protein, Tp30 as a kit to study the effectiveness of therapeutic treatment of drugs as well as various gene therapy protocols in both in vitro cultures and in vivo studies, for drug development and treatment efficacy evaluation. Included in this last example is also the future application of gene therapy protocols in the attempt to correct the disease situations where unscheduled incidents of programmed cell death occur.
In summary, the present invention provides a cost-effective and easy procedure that can be widely used in the evaluation of cell death frequency, and therefore the health status of any tissue, and can be routinely performed in any clinical laboratory.
DESCRIPTION OF THE DRAWINGS
FIG. 1. Effect of serum deprivation on DNA synthesis, survival, and terminin expression in mouse 3T3 fibroblasts. (A) Cell survival was measured for mouse 3T3 cells during serum deprivation. Cell viability was measured as described under Experimental Procedures using the trypan blue exclusion test. The data presented is the average of three experiments (± standard error of mean). Cell survival of the mouse 3T3 cells significantly decreases after 15 and 18 h of serum deprivation. (B.C) Detergent-insoluble fractions were prepared from proliferating sparse (SPA) and serum deprived (DEPRIVED) cells for the indicated times. One hundred fifty micrograms of proteins was loaded per lane. Control with PAI ascites which bears no specific antigenic reaction against cell extract of the same preparation is shown in the first lane. All the other lanes were incubated with the anti-terminin mouse monoclonal antibody (Mab 1.2). The synchronized fibroblasts were deprived of serum for 0.5, 6, 12, 24, 48, and 96 h. Electrophoresis and immunoblots with the PAI ascites and the Mab 1.2 antibody were performed as described under Experimental Procedures. Identifications of terminin proteins (as identified by their molecular weights) are shown on both sides. The Tp30 protein appears with serum deprivation as opposed to the presence of TP90/63/60 in sparse 3T3 fibroblasts.
FIG. 2. Study of expression of terminin in GM3529 fibroblasts during serum deprivation. Detergent-insoluble fractions were prepared from senescent GM3529 human diploid fibroblasts (HDF) under 10% serum (+serum) or serum-deprived (-serum) conditions for 28 days and immunoblotted with the anti-terminin mouse monoclonal antibody (Mab 1.2). Control with PAI ascites (PAI; of no specific activity) against a protein extract of HDF in 10% serum is shown in the first lane. Electrophoresis and immuno-blots proceeded as previously described in the legend to FIG. 1. The band at 40 kDa (*) observed on the immunoblot with Mab 1.2 from the senescent culture is also observed in the PAI control lane against the same extract and is thus nonspecific. The presence of Tp30 is observed during serum deprivation in a protein extract from senescent human diploid fibroblasts and not in the same cell culture in the presence of serum.
FIG. 3. Study of the induction of Tp30 during cell death. A detergent-insoluble fraction was prepared from mouse 3T3 cells treated with 10 μM cytosine β-D-arabinofuranoside (Ara-C) for 24 h and immunoblotted with the anti-terminin mouse monoclonal antibody (Mab 1.2). Control with PAI ascites (PAI) against the same extract is included in the first lane. Electrophoresis and immunoblot analysis was pursued as previously described in the legend to FIG. 1. The appearance of Tp30 with cell death as induced by Ara-C in Swiss 3T3 cells is observed.
FIG. 4. Results of revival experiments and terminin expression in mouse 3T3 cells. Cells were deprived of serum for 1.5 to 96 h. All cultures were subsequently supplemented with fresh serum to a final concentration of 10% for 48 h (revival), as described under Experimental Procedures. Immunoblot analysis (as described in the legend to FIG. 1) was carried out against a protein extract obtained from cells that were serum deprived for 12 h and subsequently "revived" with medium supplemented with 10% serum for 48 h. Note the increased expression of Tp60.
FIG. 5. Inhibition of cell death by cycloheximide in Swiss 3T3 cells after serum deprivation. The Swiss 3T3 cells were synchronized by confluency for 24-48 h. (A) The fibroblasts were passaged to serum-free conditions without (open diamond) or with pretreatment for 30 min with cycloheximide at 10 -3 M (closed diamond), 10 -4 M (open square, dotted line), 10 -5 M (open square), 10 -6 M (closed square). Each data point is the average of triplicate culture wells. (B) The 3T3 cells were grown in confluency and then transferred to serum-deprived conditions (5 min) (lane A) or the fibroblasts were pretreated with 10 -5 M cycloheximide for 30 min and serum deprived for 24 h (lane B). Cell viability and immunoblot analysis were performed as described under Experimental Procedures. Cycloheximide pretreatment (10 -4 M) can delay death induced by serum deprivation up to 24 h of the latter treatment and decrease the amount of Tp30 in these cells.
FIG. 6. Fluorescence micrographs showing terminin staining activity in mouse 3T3 cells during serum deprivation-induced cell death. The Swiss 3T3 cells were grown in 10% serum (A) and transferred to serum-free medium for 6 h (B), 24 h (C), or 96 h (D). Illustrations show immunofluorescence results, n. nucleus; c, cytoplasm, Magnification factor, ×480. Cells were stained as described under Experimental Procedures. Upon serum deprivation, diffuse immunostaining by the anti-terminin monoclonal antibody in the cytoplasm of the 3T3 cells, which becomes granular by 96 h of serum removal, was detected.
FIG. 7. Kinetics of the onset of apoptosis in mouse 3T3 fibroblasts. Mouse 3T3 cells were deprived of serum for 30 min. 2, 6, 12, 18, 24, and 48 h. Control cultures (0 h) included here are those of sparse cells density without serum deprivation. Twenty micrograms of DNA was loaded in each lane and analyzed as described under Experimental Procedures. DNA fragmentation to an oligonucleosomal ladder (apoptosis) became visible by 18 h of serum deprivation in 3T3 cells and increase in intensity with time.
DETAILED DESCRIPTION OF THE INVENTION
A. IDENTIFICATION OF TP30
In earlier studies the inventor determined that there was a biochemical difference in the terminin sub-species between young growing/nongrowing (terminin in the 90 kDa form) and senescent (terminin in the 60 kDa form) fibroblasts. The inventor observed that senescent fibroblasts were resistant to apoptosis upon serum deprivation up to 4 weeks and before this time there was no change in the molecular weight of terminin (Tp60). These results prompted the investigation of the modulation of terminin upon cell death induction.
The inventor studied changes in the size of terminin protein during apoptosis and concluded that the modification of terminin is one of the biochemical events in the pathways leading to an apoptotic death. In particular, they found that during apoptosis induced by serum deprivation in Swiss 3T3 mouse fibroblasts there is specific proteolytic degradating Tp90 and Tp60 into Tp30, a 30-kDa terminin polypeptide and this precedes the massive DNA fragmentation event. These findings suggest that the proteolytic product, present in the 30-kDa form (Tp30), can be used as a biochemical marker for signalling the "apoptotic-related" events in fibroblasts.
EXPERIMENTAL PROCEDURES
Cell lines and culture conditions. Mouse swiss 3T3 fibroblasts were cultured in Dulbecco's modified medium (DMEM) supplemented with glutamine, 10% fetal bovine serum (FBS), and 50 U/ml penicillin/50 μg/ml streptomycin. In each experiment 5×10 5 cells were seeded in 100-mm petri dishes. Normal human fibroblasts derived from a 66-year-old donor (GM 3529) were cultured to senescent state by a rigid schedule of serial passaging in the monolayer cultures as described in Wang, E and Tomaszewski, G. 1991. J.Cell. Physiol. 147:514. Exponentially growing 3T3 cells were cultured for 16 to 24 h in DMEM containing 10% FBS.
Serum deprivation and revival culturing conditions. For serum deprivation, the cells were grown to confluency (3×10 4 cells/cm 2 ) in DMEM supplemented with 10% FBS and left in the quiescent state for 24-48 h. The cells were subsequently washed once with fresh DMEM, transferred to DMEM without serum at a lower cell density (1.5×10 4 cells/cm 2 ), and incubated for up to 96 h. For the experiments to test the kinetics of revival ability of cells which had been deprived of serum for various time periods, the medium lacking nutrients was replaced with DMEM supplemented with 10% serum and the cells were left in the presence of serum-containing medium for 48 h.
Cell viability assay. Since dead cells detach from their substratum, we harvested the medium containing floating cells and collected the adhering cells by trypsin treatment. The two fractions were pooled and centrifuged at 1200 g for 10 min at 4° C. Cell viability of the total cell population was estimated by adding an equivalent volume of a 0.4% trypan blue solution (GIBCO Laboratories, Grand Island, N.Y.) to an aliquot of resuspended cells and incubating for 5 min. Stained and unstained cells were counted in an hemacytometer. Mean values obtained represent data of triplicates from each separate experiment. Statistical analysis for this assay and all other experiments in this paper was done using a two-tailed Mann-Whitney test.
Cycloheximide treatment. The mouse 3T3 fibroblasts were synchronized by culturing them to confluency and maintaining them in this state for 24 to 48 h. Cells were then treated with cycloheximide at concentrations of 10 -3 , 10 -4 , 10 -5 , and 10 -6 M for 30 min and subsequently washed with fresh DMEM and transferred to serum-deprived conditions as described above.
DNA fragmentation. The technique was adapted from that described by Blin and Stafford in Nucleic Acids Res 3:2303-2308 (1976). Mouse 3T3 fibroblasts were washed in phosphate-buffered saline (PBS) and lysed in 10 mM Tris-HCl, 0.1 M EDTA, RNAse A (20 μg/ml), 0.5% SDS at pH 8.0 for 1 h. The suspension was further incubated for 3 h in the presence of proteinase K (Boehringer Mannheim, Laval, Quebec, Canada) at 100 μg/ml. Finally DNA was extracted with phenol and ethanol/sodium acetate precipitation before final precipitation with ethanol. The samples were analyzed on 1.0% agarose gel (ICN Biomedicals, Mississauga, Ontario) containing 50 μg/ml ethidium bromide. Electrophoresis was carried out in TE buffer (10 mM Tris-HCl, 1 mM EDTA at pH 8.0) for 18 h at 20 V.
Immunofluorescence microscopy. For indirect immunofluorescence microscopy of cultured cells, the fibroblasts of predetermined growth properties were cultured on glass coverslips. All the fibroblasts were fixed in 50% methanol:50% acetone for 10 min at -20° C. After air drying, the cells were rehydrated in PBS at pH 7.2 and incubated with the anti-terminin mouse monoclonal antibody (Mab 1.2) overnight at room temperature. The specimens were washed three times with PBS and incubated for 30 min with rabbit anti-mouse immunoglobulin G+immunoglobulin M (IgG+IgM) immunoglobulins (ICN Biomedicals) at room temperature. The samples were rinsed three times with PBS and incubated with fluorescein-conjugated goat anti-rabbit IgG (ICN Biomedicals) and incubated as before. The cells were finally washed with PBS and mounted in glycerol-containing PBS for epi-illumination examination of immunoreactive samples with a Nikon Labophot microscope.
Cell solubilization, SDS-PAGE, and immunoblotting. All the manipulations were done at 4° C. Fibroblasts (3×10 6 cells) were washed with PBS and lysed in 1 ml of RIPA buffer (10 mM Tris-HCl, 150 mM NaCl, 1% Triton X-100, 0.1% SDS, 1 mM EDTA at pH 7.4) containing 0.5 mM phenylmethylsulfonyl fluoride (PMSF) (Sigma Chemicals, St. Louis, Mo.), 10 μg/ml aprotinin (Boehringer Mannheim), 2 μg/ml each of pepstatin and leupeptin (Boehringer Mannheim) and subsequently scraped and incubated for 10 min on ice. The samples were washed at 15,000 g at 4° C., and the detergent-insoluble fraction was washed once with 10 mM Tris-HCl, pH 7.4. The pellet was digested with 0.1 mg/ml of DNAse I (Sigma Chemicals) in a Tris buffer containing 10 mM Tris-HCl, 150 mM NaCl, 5 mM MgCl 2 at pH 7.4 supplemented with PMSP and aprotinin at 4° C. for 2 h with constant mixing. The sample was centrifuged for 10 min and further washed once with 10 mM Tris-HCl, 10 mM NaCl at pH 7.4 and a second time with Tris buffer only. The insoluble fraction was suspended in 10 mM Tris-HCl, 100 mM NaCl, 0.4% SDS at pH 7.4 containing PMSF, aprotinin, leupeptin, and pepstatin as mentioned above, sonicated briefly, boiled for 10 minutes, and analyzed on SDS-PAGE as described by Laemmli in Nature 227:680-685 (1970). After transfer to nitrocellulose paper as described by Laemmli, the blots were incubated with anti-terminin mouse monoclonal antibody (Mab 1.2), and the rabbit anti-mouse IgG (whole molecule) (Cappel Organon Teknika N.V., Turnhout, Belgium) was used as second antibody and peroxidase-conjugated goat anti-rabbit IgG (whole molecule) (Cappel) as the tertiary antibody with 4-chloro-1-naphtol (Sigma Chemicals) and H 2 O 2 as peroxidase substrate. Nonspecific immunoreactive bands were identified by incubation with control ascites generated from a mouse myeloma cell line (PAI) which secretes no specific antigenic activity.
RESULTS
Induction of Cell Death during Serum Deprivation
Factor withdrawal is known to induce apoptosis in many systems. To examine the expression of terminin during the induction of cell death, the inventor chose to study mouse 3T3 fibroblasts which were maintained under three different culturing states: proliferating (log phase), serum-deprived, and "revived" cells. The cell viability during such treatments was ascertained by the trypan blue dye staining method. To optimally synchronize growth status, all cultures were initiated from completely quiescent cells, accomplished by leaving confluent monolayers (3×10 4 cells/cm 2 ) in 10% serum for 24 to 48 h. After passing the cultures of a lower cell density (1.5×10 4 cells/cm 2 ) to media containing either 10 or 0% serum, subconfluent cells cultured in 10% serum (control) were shown to grow exponentially by 3 H!thymidine incorporation. In contrast, the proliferative capacity was lost in cultures in medium with 0% serum. FIG. 1A shows the effect of serum deprivation on the survival kinetics of 3T3 cells. After a period of 12 h where relatively few cells were dying, there was a gradual loss of viability up to 96 h.
The Inventor further analyzed terminin expression in cells at various stages of these physiological states by immunoblotting. Control proliferating cells contained terminin in three forms with different relative molecular masses: Tp90 (terminin protein, 90 kDa), Tp63 (terminin protein, 63 kDa), and Tp60 (terminin protein 60 kDa); most immunoreactive material was found in the slowest migrating band (Tp90) (FIG. 1B). No cross-reactive band could be observed in the control PAI incubation. After 24 h of serum deprivation, Tp90 was reduced, Tp60 was increased, and Tp63 was underrepresented in parallel with the appearance of a new band of immunoblot analysis with M, 30 kDa (Tp30). Tp30, which was already visible after 30 min of serum removal, became the principal polypeptide species, which increased in intensity in later time points, as observed in immunoblot analysis using the monoclonal antibody, up to 96 h (when most cells were dead) (FIG. 1C). To evaluate the possibility of general protein degradation during this specific process of induced cell death, we studied the expression of actin by immunoblot analysis and found that the actin was stable up to 24 h (data not shown).
To verify if the same phenomenon of appearance of Tp30 during cell death could occur in other cell lines, we performed the same serum deprivation experiments with human diploid fibroblasts (GM3529; donor, 66 years old). Transfer of in vitro aged human cells to serum-depleted medium also lead to the appearance of Tp30 as the major protein after 28 days of such treatment (FIG. 2), as opposed to Tp90 and Tp60 expression in serum-containing young and senescent fibroblast cultures, respectively as described in Wang and Tomaszewski, J. Cell Physiol 147:514-522 (1991). Consequently, mouse 3T3 and human fibroblasts responded to serum removal and induction of cell death in a similar fashion, by generating Tp30, except the timing of its appearance takes longer for senescent fibroblasts.
The inventor investigated whether the Tp30 was generated because of the specific proteolysis, which is activated due to the sparse density conditions of serum deprivation only, or during general cell death mechanism. To approach this, cell death was induced in the mouse 3T3 cells with the chemical agent cytosine β-D-arabinofuranoside (Ara-C) at 10 μM for 24 h which will kill any cell getting into DNA synthesis, and this killing effect occurs even in presence of 10% serum (Tamm et al. Proc. Natl. Acad. Sci. USA 88:3372-3376 (1991)). As shown in FIG. 3, the Tp30 immunoreactive band appeared by immunoblot in the Ara-C-treated dying population of cells, along with a weak band of Tp90 as opposed to the presence of Tp90/63/60 in the untreated cells as seen in FIG. 1B. These results established that the Tp30 appearance was specific to a death-related phenomenon.
To further correlate the Tp30 presence and the activation of the death process by serum deprivation process, the 3T3 fibroblasts were revived with fresh serum at various times after serum removal. The ability to revive cells by adding 10% serum back to the culture can only be achieved up to 24 h of serum deprivation. Any time thereafter, for example, after 48 h of serum deprivation, revival cannot be done as demonstrated by the trypan blue exclusion assay. Survival kinetics during revival showed that cells could be revived with the maximum of 18 h of serum deprivation. Furthermore, upon immunoblot analysis, it was demonstrated that Tp60 became the major terminin species when cells that were deprived of serum for 12 h were revived with medium supplemented with 10% serum for 48 h (FIG. 4. This suggests that mouse 3T3 fibroblasts after 24 h of serum deprivation appear to be committed to the cell death mechanism and may have permanently lost the ability to be revived.
A striking feature of death induced by factor withdrawal is its highly modulated response by protein synthesis inhibitors such as cycloheximide (CHX); a decline in protein synthesis during apoptosis usually delays or inhibits cell death. Since Tp30 appearance seems to be an early event during induction of cell death by serum removal, the effect of CHX on the survival kinetics of Swiss 3T3 cells and Tp30 expression was investigated. CHX was added to control proliferating cells for 30 min (pretreatment) and then removed before serum deprivation. CHX was tested at concentrations of 10 -3 , 10 -4 , 10 -5 , and 10 -6 M. CHX (10 -4 M) significantly increased (0.02<α<0.10) the proportion of cells remaining viable between 1.5 and 24 h of serum deprivation, compared to cells which were not pretreated with CHX but were serum deprived (control population) (FIG. 5A). Furthermore, CHX added to 3T3 cells during serum deprivation at Time 0 for 5 or 20 h became lethal to the cells (data not shown). In such circumstances, however, cells could be kept alive if serum was added with the CHX, confirming previous results (Fischback, G. D. (1972) Dev. Biol. 28:407-429). Pretreatment of confluent quiescent Swiss 3T3 cells with CHX (10 -5 M) before serum deprivation results in the reduction in the amount of Tp30 protein produced, while the intensity of the other terminin subspecies was slightly stronger (FIG. 5B). This result suggests that the CHX pretreatment may reduce the potency of the putative proteolytic action, thus the amount Tp30 with the parallel observation of the reduction the dying cell number as shown in FIG. 5A. The mechanism of induced cell death would thus require active protein synthesis and modulation of Tp30 expression.
Immunofluorescence microscopy shows that terminin antibody staining activity is not detected in control proliferating cells (FIG. 6A). After 6 h in serum-free medium, antibody staining was detected predominantly in the cytoplasm, concentrated around the nucleus (FIG. 6B). By 24 h after serum deprivation, immunoreactivity appeared to be evenly distributed throughout the cytoplasm (FIG. 6C). None of the floating dead cells showed any reactivity to the antibody. After 96 h of serum removal, a condensed "granular" type of staining was observed in cells which appeared to have lost most of their cellular organization (FIG. 6D). The cytoplasmic staining present in the serum-deprived culture, specifically those cells which remained attached to the substratum, disappeared when fresh medium containing 10% serum was added in time during serum deprivation and as described in the legend to FIG. 4 (data not shown). The addition of nutrients during serum deprivation may thus abolish the induction of immunodetectable terminin in the revived cells.
Induction of DNA Fragmentation during Serum Deprivation
The inventor verified the nature of death mechanism induced in their system by serum deprivation by extracting DNA at the indicated time points (FIG. 7). No DNA degradation was visible when obtained from (1) proliferating cells in 10% serum and (2) 3T3 cells which sustained serum removal up to 8 h. As shown in FIG. 7, DNA degradation into oligonucleosomal-size fragments was observed by 12 h after serum deprivation of the confluent cultures (FIG. 7). DNA fragmentation to an oligonucleosomal ladder became clearly visible by 18 h of serum removal and increased with time up to 96 h. The same DNA ladder was observed when cells were killed by the Ara-C treatment as described in the legend to FIG. 3. CHX pretreatment (10 -4 M) followed by serum deprivation for 24 h resulted in a visible reduction in the intensity of DNA fragmentation and the disappearance of the low-nucleosome-size fragments. These results suggest that CHX pretreatment can delay both the DNA fragmentation and the appearance of Tp30 in the serum-deprived Swiss 3T3 cells.
DISCUSSION
Understanding the mechanism of programmed cell death is currently the focus of many studies. Morphological features and DNA fragmentation into oligonucleosomal fragments are the only characteristic features of apoptosis in most of the systems studied so far. These features might be the result of the late events in the cascade leading to cell death. There would be several preceding (including proteolysis) events taking place before the DNA fragmentation and morphological changes.
The results presented above demonstrate the role of specific proteolysis of a known protein during the programmed cell death. Terminin was identified as a 90-kDa protein in young growing and nongrowing cells and in senescent human diploid fibroblast as a 60-kDa cytoplasmic protein. The anti-terminin monoclonal antibody 1.2 cross-reacted with a 90- and 60/63-kDa polypeptides in healthy 3T3 cells. Furthermore, the appearance of Tp30 as a result of specific proteolysis of Tp90 and Tp60/63 after serum withdrawal in mouse 3T3 fibroblasts can be used as a good cellular marker for indicating the initiation of cell death. Serum deprivation in this cell line activates apoptosis as shown by DNA fragmentation into oligonucleosomal-size fragmentation. The terminin protein of 30 kDa (Tp30) appears very early after serum deprivation, even before a noticeable degree of DNA fragmentation can be observed (18 h), and in parallel with immunohistochemical detection of terminin antibody staining within the cytoplasm of the cells. The results obtained with the induction of cell death by a chemical agent in the presence of serum further suggest that the process seen here resembles other apoptotic events such as glucocorticoid-induced cell death (Galili et al. (1984) Cancer Res. 44:4594-5601) and that Tp30 is indeed an early marker signalling this phenomenon, even before any events leading to final death occur.
When subjected to serum deprivation, senescent human fibroblasts were resistant to cell death and remained alive for several weeks after serum deprivation (inventor's unpublished results); the 60-kDa terminin species remains at the same level of quantity and the same molecular weight. However, when Swiss 3T3 cells were subjected to serum deprivation as described before, they underwent apoptotic cell death immediately and there was specific proteolytic degradation of Tp90, Tp60, and Tp63 into the 30-kDa form of the terminin polypeptide which increased with time. This result suggests that this kind of proteolysis might by playing an important role and is an early event in the process of cell death. The degradation of larger size terminin polypeptide into the 30-kDa form (Tp30), which is resistant to further degradation, might be due to either the activation of a specific protease or the accessibility or susceptibility of terminin polypeptides to a general protease action during the induction of apoptosis in 3T3 cells. Nevertheless this proteolytic action may play a significant role in programmed cell death and may be at the same time indirectly associated with the proteolysis of terminin polypeptides to the 30-kDa form.
Proteolysis of lamin B and topoisomerase I and II has been shown to occur during drug-induced apoptosis of myeloid (Kaufmann, S. H. (1989) Cancer Res. 49, 5870-5878) and mesenchymal cells (Ucker, D. S. Obernmiller, P. S. Eckhart, W., Apgar, J. R. Berger, N. A., and Meyers, J. (1992) Mol. Cell Biol 12. 3060-3069). It has been suggested that proteolytic events at nuclear membrane and matrix may precede internucleosomal cleavage of DNA by endonucleases (Oberhammer, FP., Wilson, J. W., Dive C., Morris I. D. Hickman, J. A., Wakeling, A. E. Waker P. R. and Sikorska, M. (1993) EMBO J. 12. 3679-3684). It has been observed that there is cleavage of DNA into 300- and/or 50-kDa fragments prior to actual internucleosomal fragmentation (Wyllie, A. H. (1992) Cancer Metastasis Rev. 11 95-103). The results suggest that the specific proteolysis of terminin, which is a cytoplasmic protein, is an earlier cellular event which occurs before the massive DNA fragmentation.
It is well established by now that factor withdrawal induces cell suicide as demonstrated with neuronal cells requiring nerve growth factor to survive (Martin, D. P. Schmidt, R. E. DiStefano, P. S. Lowry, O. H., Carter, J. G., and Johnson, E. M.,Jr. (1988) J. Cell Biol 106, 829-844) and lymphocytes depending on a specific lymphokine to live (Kyprianou, N. and Isaacs, J. t. (1988) Endrocrinology 122:552-562). The death process can be prevented by interference with macromolecular synthesis (Landon, C., Nowicki, M., Sugawara S., and Dennert, G. (1990) Cell Immunol. 128, 412-426). Apoptosis in the fibroblast system studied here required protein synthesis since the process was delayed by pretreatment of the cells with CHX as observed with MCF-7 breast cancer cells under the same conditions (Geier, A., Beery R., Haimshon, M., Hemi, R., and Lunenfeld, B. (1992) Cell. Dev. Biol. 28A, 415-418). Such a delay of the death process is also suggestive that necrosis is not being studied since it was shown that the latter is increased by CHX in various tissues (Martin, D. P. Schmidt, R. E. DiStefano, P. S. Lowry, O. H., Carter, J. G., and Johnson, E. M.,Jr. (1988) J. Cell Biol 106, 829-844). CHX treatment also caused decrease in the proteolysis of Tp90 and Tp60 as shown by the reduction in the amount of Tp30 expression. Meanwhile, the intensity of the Tp90/63/60 proteins became darker. The correlation between the reduction of Tp30 and the rescue from death by CHX treatment further suggests that the presence of Tp30 is a result of specific proteolysis of terminin as an apoptosis-dependent event.
The revival experiments with fresh serum demonstrated the time-dependent fashion for the final death event occurring during apoptosis. A population of mouse 3T3 fibroblasts could reenter the traverse of the cell cycle after 24 h at maximum serum deprivation if and when they are supplied with serum again. These results confirmed that the process leading to the final death was reversible up to a certain "commitment" as previously reported by Dowd D. R, and Meisfeld Dowd, D. R., and Miesfeld, R. L. (1992) Mol. Cell. Biol. 12, 3600-3608. It is well established that mouse 3T3 cells can be revived after serum deprivation (Zetterberg, A., and Larsson, O. (1985) Proc. Natl. Acad. Sci. USA 82, 5365-5369). This was exemplified with another cell line, rat fibroblasts, which during factor removal could escape the first wave of apoptosis and start DNA synthetic activity at about 12 h of serum deprivation (Evan G. I. et al. 1992. Cell 69:119-128). In the present study, the possibility of going through the cell cycle traverse once again by cells that have been serum deprived for 24 h is probably due to a residual subpopulation of fibroblasts which still express, between 24 to 48 h of serum withdrawal, the Tp90, Tp63, and/or Tp60 proteins and are not far ahead into the apoptotic process. The refractoriness to do so after 24 h of serum removal could well be correlated with the extensive DNA fragmentation which occurs thereof and which could be part of the commitment step to cell death.
Tp30 remains an early marker for commitment of cell death and supports the hypothesis that Tp30 is implicated in a specific death-related signalling cascade. Indeed, the importance of Tp-30 during cell death is signified by (1) its increasing amount with time up to 48 h during serum deprivation and treatment with cell-killing agents; (2) its decreased concentration in cells pretreated with cycloheximide undergoing delayed apoptosis; and (3) its decreased amount in cells rescued from death by adding serum back to the culture. Furthermore, a high level of DNA fragmentation occurs already at 24 h at which time point Tp30 expression is at its maximum. These results suggest that the apoptotic and not necrotic event in mouse 3T3 cells during serum withdrawal is being examined.
B. APPLICATIONS OF INVENTION
With the knowledge that Tp30 can be used as a marker for cell death commitment, many practical applications for the Tp30 protein, the Tp30 nucleic acid sequence and antibodies to Tp30 can be realized.
For example, the monoclonal antibody (Mab 1.2) can be used to detect cell death status in several situations as follows:
1. routine pathological diagnostic tests of solid tissues;
2. fluorocytometric studies of peripheral lymphocytes;
3. assessment of the effectiveness of chemotherapeutic drugs; and
4. assessment of the effectiveness, by the consequential impact on cell death status, of gene therapy.
The following sections describe some of the ways in which the presently available monoclonal antibody (Mab 1.2) can be used in the detection of cell death status.
1. Routine pathological evaluation of cell death status of solid tissues
This assay can be performed first by immunohistochemical assays in combination with immunoblotting assays. Biopsy tissues are separated into two portions. One portion is processed by formaldehyde-fixation or rapid freezing for frozen sectioning; 6-10 micron sections are incubated with either the Mab 1.2 hybridoma culture supernatant or the ascites form. After incubation overnight at room temperature, these specimens are further incubated with secondary antibody conjugated with fluorescein isothiocyanate for immunofluorescence microscopy, or with horseradish peroxidase for immunoperoxidase examination. The completed processed samples can then be examined for cytoplasmic staining activity by positive reaction. After evaluation by microscopic examination that a positive reaction is present, the second portion of the biopsy tissue is then processed for extraction of the detergent-insoluble fraction, which is then processed for SDS-PAGE electrophoresis to separate the different protein species in the extract, followed by transferring to nitrocellulose (NC) paper and reaction with Mab 1.2. The detection of Tp30 presence is accomplished by hybridizing Mab 1.2 with the NC paper, followed by a revealing reaction with secondary antibody conjugated with horseradish peroxidase. The cell death status can be determined by the qualitative and quantitative presence of a Tp30 band, as well as the positive staining reaction with Mab 1.2.
At present, cell death status can be evaluated based on DNA integrity. The popular assays for this determination are either the biochemical assaying DNA on agarose gel for DNA breaking into oligonucleosome ladders, or immunohistochemically assaying the nicked end of DNA by labelling the free DNA end with fluorescein or horseradish peroxidase-conjugated UTP via terminal transferase. Routinely, one can also examine nuclear morphology by propidium iodide (PI) staining. All three assays (DNA ladder, end-labelling, and PI labelling) are gross measurements and only good for those cells that are already dead or at the end stage of dying. Compared with these three assays, the present invention using the monoclonal antibody to Tp30 is superior, since it detects not only those cells that are dead but also those cells that are committed to die. Therefore, it provides a broader picture of death status with a quantitative estimation of Tp30 presence.
2. Fluorocytometric studies of cell death status with peripheral lymphocytes
The present technology of fluorocytometric studies employs the identification of cells at three different phases of the cell cycle: G 1 , S. and G 2 . This is largely performed by DNA quantity staining by propidium iodide labelling. Since the dying cell population contains the same DNA quantity as the living counterparts at any of the three phases of the cell cycle, there is no way to distinguish the two cell populations. The present invention allows one to perform double labelling for terminin (Tp30) positivity and propidium iodide (PI) staining together. Measurement of the labelling indices for Tp30 and PI staining can be used in combination to obtain the exact fractions of those cells in G 1 that are living (Tp30-positive) and dying (Tp30-positive). Similar estimation can be made for the S-phase and G 2 phase cell populations.
Peripheral lymphocytes may be obtained according to the standard procedure through Ficoll gradient separation, and then processed for formaldehyde fixation and extraction with 0.05% Triton. Afterwards, the cell specimens are incubated with monoclonal antibody (Mab 1.2) to Tp30 overnight at room temperature or at 37° C. for one hour. This is followed by further incubation with fluoresceinated goat antimouse antibody, and subsequent incubation by propidium iodide staining. The completely processed cell specimens are then evaluated by fluorocytometric measurement on both fluorescence (Tp30) and rhodamine (PI) labelling intensity on a per cell basis, with the same cell population simultaneously.
3. Assessment of inhibitory effect on cell growth by chemotherapeutic induction of programmed cell death
So far, the routine method to determine whether a particular chemotherapeutic drug can inhibit cancerous cell growth is to examine cell population size either in culture, by measuring the reduction in cell colony size or number, or measuring soft agar colony growth or in vivo tumor formation in nude mice. All three procedures require time for development of the colonies or tumor to be large enough to be detectable. Experiments involved in these approaches in general require large-scale planning and multiple repeats of lengthy experimental span (at least three weeks). Often these assays do not take into account the fact that a drug may not be inhibiting cell growth, but rather killing the cells; this type of effect may be a more favorable consequence needed for chemotherapeutic treatment of cancer. Previously the inventor isolated a 57 kDa protein, termed statin, that is specific for quiescent, non-cycling or non-proliferating cells. (Mitmaker et al., Eur.J.Histochem. 37:295-301, 1993). The inventor also has developed a monoclonal antibody S-44 that is specific for statin. Statin and the monoclonal antibody S-44 are useful in assessing the non-proliferating population of cells in a given tissue which indirectly gives a measure of the proliferating component of a tumor or cell mass. The combination of using statin antibodies to detect the nonproliferating cell population pool, and terminin antibodies to detect the dying cell population pool, provides a powerful and rapid assessment of the effectiveness of any given drugs in the containment of cancerous cell growth. Specifically, the antibody to statin allows evaluation of whether the drug treatment inhibits the cancerous cells from further growth (statin is absent in both proliferating and dying cells), and the antibody to terminin Tp30 provides the means to study whether, and to what extent, the drug treatment kills the cells. Application can be easily performed at the immunofluorescence microscopic level with cultured cells or tissue sections, and the results can be obtained both qualitatively and quantitatively in a week. All together, these approaches can avoid the time-consuming and manpower-demanding assays such as colony formation, soft agar, or tumor production determinations.
4. Assessment of pharmacological intervention on inhibition of cell death frequency in degenerative diseases
In contrast to neoplasia, where the disease develops due to too many cells growing, many clinical symptoms are derived from losing functional units through too many cells dying. For degenerative diseases such as Alzheimer's or Parkinson's disease, these losses may be due to the premature activation of the cell death program in neurons. In osteoporosis, the cell loss may be due to an improper balance between osteoblast and osteoclast cells, due to the too active programmed cell death process killing more cells than the bone tissue can afford. Other related phenomena may also occur in the wound healing process, tissue transplantation and cell growth in the glomerus during kidney infection, where the balance between living and dying cell populations is an essential issue to the health status of the tissue. The present invention provides a rapid assessment of dying cell populations through the immunohistochemical and biochemical measurements of Tp30 presence in degenerative tissues.
5. Assessment of cell death in tissue due to infection by bacteria and HIV and other classes of viruses that can induce cytopathic effects
In general, many viral infections are accompanied by the final disintegration of the infected cells. Traditionally, the precipitous effect of these viral infections is the activation of programmed cell death, therefore allowing the cells to contain the scope of infection in a given tissue. However, if this suicide is too active to be stopped at the right level, tissues will lose too many cells during the course of infection, therefore resulting in an adverse effect and ultimately a disease situation. One of the most noted examples is the activation of CD4 T-cells to kill other cell types, in HIV infection. The present invention using the monoclonal antibody to Tp30 allows us to measure cell death status in terms of frequency and dying cell population in bacterially- and virally-infected tissues. Measurements of cell death status can be performed by the immunohistochemical and immunoblotting techniques described above and in Hubert, Pandey and Wang (1994). Similarly, the present invention can also determine the effectiveness of any treatment regimens in terms of reduction or suppression of cell death frequency and scope.
6. Assessment of cell death status in oligodendrocytes associated with Multiple Sclerosis
Positive staining of monoclonal antibody to terminin Tp30 occurs in dying cultured human oligodendrocytes. The programmed cell death event is activated in these oligodendrocytes by total deprivation of serum, or by treatment with tumor necrosis factor (TNF). The inventor is examining whether the promiscuous killing of oligodendryocytes by CD4 cells is also associated with the appearance of Tp30. If so, the inventor may be able to explain whether the loss of oligodendrocytes associated with multiple sclerosis (MS) is due to the induction of programmed cell death by the CD4 cells, which come in contact with the oligodendrocytes when the blood-brain barrier deteriorates. Therefore, the present invention can be used in cultured oligodendrocytes to ascertain how drug intervention can deter the programmed cell death event in terms of frequency and scope in this cell system. In this context, the invention could help discover a drug which reduces the oligodendrocyte loss associated with the MS syndrome.
7. Assessment of cell death status in archival pathological tissue specimens that have been processed by the routine procedure of formalin-fixation and paraffin-embedding
Normally, biopsy or autopsy samples processed in most clinical pathology laboratories are prepared in a harsh way of formalin fixation and paraffin embedding. While this is an accepted procedure for preservation of tissue morphology, fit for long-term storage and repeated examination, it destroys the antigenic activity necessary for studies by most antibodies. thus it becomes necessary to prepare frozen sections from tissue block that have been spared the above procedure, instead using the flash-freezing technique. Although most hospital pathology laboratories have adapted to this requirement, it is still not a routine procedure, and only selected samples are processed for frozen sections. It is apparent that if an antibody can stain both frozen and formalin/paraffin-prepared samples it will have a significantly broadened scope of application. Recently, we have found that the antibody to terminin (Mab 1.2) fits the criterion. In particular, it provides positive staining reaction in archival pathological samples of breast cancer tissues.
8. Assessment of cell death status in pharmacological studies in animal models
Attempting to control either a reduced cell death rate, in the case of cancer, or an increased cell death rate, in the case of neurodegeneration, has been recently seen as a new mode of disease intervention. Numerous approaches via either intervention with known drugs or gene therapy are in progress, starting from the base of correcting the altered programmed cell death process, with the concept on maintaining a balanced cell mass in any given tissue. For these therapeutic interventions, the bridge between studies in cultured cells and clinical trials is animal studies, i.e. success in intervention with animal models, in either routine laboratory animals or transgenic mice bearing either knock-out or overexpression phenotypes. Terminin antibody (Mab 1.2) is a powerful tool for examining apoptotic death status in terms of change in dying cell numbers between normal and experimentally manipulated animals. In this context the invention, as a diagnostic tool for assessing cell death status, could help to determine the efficacy and potency of a drug or a gene therapeutic approach. | Apoptosis or programmed cell death is a tightly regulated mechanism used by the body to eliminate excess cells in a given tissue. If this mechanism fails, resulting in too many cells, cancer may develop in certain tissues. If the mechanism is overactive, resulting in the destruction of too many cells, tissue degeneration can occur. Therefore being able to identify which cells are destined to undergo apoptosis is critical in allowing clinicians, pathologists and researchers to develop means to detect, diagnose or treat disorders wherein the natural regulation of cell death events is interrupted. The present inventor has identified a 30 kDa protein, designated Tp30, that is specific for cells that are programmed to die. A monoclonal antibody specific for Tp30 has also been identified. The Tp30 protein and monoclonal antibodies thereto are useful in the detection and therapy of disorders wherein the natural regulation of cell death events is interrupted. Such disorders include cancer, bone degeneration, autoimmune diseases, neurodegenerative diseases, cardiovascular disorder, ischemia, HIV-associated illness and kidney malfunction. | 2 |
CROSS REFERENCE TO RELATED APPLICATION
This is a continuation of international application PCT/EP00/04554 filed May 19, 2000, and designating the U.S.
BACKGROUND OF THE INVENTION
The present invention relates to a heating device for heating an advancing yarn in a texturing machine or the like.
Such heating devices are used in particular for crimping synthetic yarns in a false twist texturing machine, through which the yarn advances and is crimped. In so doing, the yarn advances in a heating channel, which is heated on its walls to a surface temperature that is above the melt point of the yarn. To this end, the heating channel contains a plurality of yarn guides, which guide the yarn at a distance from the walls of the heating channel. The yarn guides may be arranged on a support, which is exchangeably arranged in the heating channel. A heating device of this kind is disclosed, for example, in EP 0 731 197 and corresponding U.S. Pat. No. 5,628,176.
To set a twist previously imparted to the yarn, a heat treatment is needed, which covers the entire yarn cross section, so that in the known heating device, each yarn is guided in a separate heating channel. This ensures that in the case of multifilament yarns, each of the filaments receives an intensive heat treatment for crimping. The known heating device is unsuitable for the heat treatment of a plurality of parallel advancing yarns.
DE 196 50 677 discloses a heating device, which is used for heating a group of advancing yarns. In this process, the group of yarns advances in a heating channel in a yarn advancing plane parallel to the side walls of the heating channel. Such arrangements are unsuitable for use in texturing machines, inasmuch as they do not permit uniform heat treatment for crimping the individual yarns because of heat losses, in particular toward the edge of the group of yarns.
EP 0 905 295 discloses a heating apparatus for heating an advancing yarn, wherein the yarns are guided in a yarn advancing plane, which extends in spaced relationship with a heated wall. However, the publication provides no indication of how the yarn path can be stabilized, so that the yarn undergoes a uniform temperature treatment.
It is accordingly an object of the invention to further develop a heating device of the initially described kind such that one or more yarns advancing side by side receive a uniform heat treatment.
SUMMARY OF THE INVENTION
The above and other objects and advantages of the invention are achieved by the present invention and wherein an arrangement of the yarn guides within the heating channel is selected such that they form a plurality of yarn guide tracks extending side by side for guiding a plurality of yarns, and wherein the yarns advance at a predetermined distance from the channel bottom wall. A special advantage of the invention lies in that, regardless whether one or more yarns advance in the heating device, the yarns advance substantially at the same distance from the bottom wall. The plane of the advancing yarns as well as the distance from the bottom wall are selected such that substantially the same heating times, heating intensities, and frictions are effective on each individual yarn.
To obtain a stable yarn path in the heating channel with the least possible contact and, thus, the least possible looping friction, the yarn guides are arranged relative to one another such that zigzag yarn guide tracks form, in which the yarns advance.
The invention has the special advantage that when a plurality of parallel extending yarns advance through a heating channel, each of the yarns is subjected to a substantially identical ambient temperature. With that, there also exists the possibility of operating the heating device either with one yarn or with a plurality of yarns.
According to a preferred embodiment of the invention, the yarn path plane formed by the yarn guides, in which the yarns advance, extends substantially parallel to the bottom wall of the channel. As a result, the yarns advance at a constant distance from the heating channel, so that a particularly uniform temperature influence on the yarns is realized. Because of the unilateral opening of the heating channel, which is closed in operation by a cover, a temperature gradient develops between the channel bottom wall and the cover side of the heating channel. Inside the channel, the yarns advance at one level within the channel, so that temperature gradients in the heating channel exert no influence on the tempering of the yarns.
In this connection, the arrangement of a particularly preferred further development of the invention results in that a very uniform treatment of the yarns within the heating channel. To this end, the number and the arrangement of the yarn guides are selected such that adjacent yarn guide tracks have between each other a distance which remains substantially unchanged in the longitudinal direction of the heater.
Another development of the invention is used preferably in texturing machines, wherein two yarns are combined to one yarn upstream of the takeup. In this type of plying, it is often desired to have different heat treatments for the individual yarns, so that different types of yarn guide tracks are realized in a simple manner.
To ensure that the support inserted into the heating channel and the yarn guides arranged thereon permit heating the yarns as unimpeded as possible, it is preferred to make the support of a thermally conductive material. In this instance, the yarn guides are made of a ceramic or coated with ceramic, so that they exhibit a high resistance to wear. This results in particular in a long service life of the yarn guides. Furthermore, ceramic has the property that it decreases the tendency as exists in the case of conventional steel yarn guides, namely to accumulate inorganic components of the yarn, and that it shows less wear.
In a particularly preferred development of the invention, the support consists of a highly heat conductive material and is designed and constructed as a profiled rail which is shaped to define a plurality of parallel extending guide channels. The external profiled walls of the profiled rail are mounted to the walls of the heating channel. This arrangement realizes a very stable yarn path in the heating channel. In this connection, there exists even the possibility that the guide channels define the yarn guide track, and that thus the yarn advances directly in the rail.
To be able to realize a zigzag yarn guide track, it is possible to mold the yarn guides to the profiled rail. However, it is also possible to insert a plurality of ceramic yarn guides into each of the guide channels of the profiled rail. In this instance, recesses in the heating rail make it possible to produce holding means for such yarn guides in a simple manner.
It is preferred to design and construct the yarn guides with an L-shaped yarn guide edge, so that the spacings between the yarn and the side walls of the heating channel, as well as between the yarn and the bottom wall of the heating channel are defined by the yarn guide edge. Likewise, this measure leads to an equalization of the temperature treatment of the yarn within the heating channel.
In a particularly advantageous further development of the invention, the profiled rail is formed by a plurality of U-shaped individual rails. The individual rails are connected along their opposite longitudinal sides, so that no heat blockade develops between the individual yarn guide tracks.
BRIEF DESCRIPTION OF THE DRAWINGS
Further advantages, characteristics, and possibilities of application of the present invention are described below with reference to the accompanying drawings, in which:
FIG. 1 is a schematic top view of a heating device having a heating channel according to the invention;
FIG. 2 is a schematic cross sectional end view of the heating device of FIG. 1 perpendicular to the plane of the advancing yarn and taken along the line A—A in FIG. 1;
FIG. 3 is a schematic view of a further embodiment of a heating device according to the invention; and
FIG. 4 is a schematic cross sectional end view of the heating device of FIG. 3 perpendicular to the plane of the advancing yarn and taken along the line B—B in FIG. 3 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIGS. 1 and 2 illustrate a first embodiment of a heating device according to the invention, and wherein the heating device includes an elongate heater body 1 , which typically has a length from 0.5 to 2 meters. In the heater body 1 , a heating channel 2 is formed that is open to one side, and extends in the longitudinal direction. The heating channel 2 is defined in the heater body 1 by parallel side walls 3 , 4 , and a bottom wall 5 .
Below the channel bottom wall 5 , the heater body 1 encloses two electric heating elements 10 . The heater body 1 consists of a highly heat conductive material, so that the heating elements 10 heat the walls 3 , 4 , and 5 of the heating channel 2 , preferably to a temperature approximately to or above the melt point of the yarn being processed.
In the heating channel 2 , a support 11 is embedded so as to be substantially flush with the inner surface of the bottom wall 5 . On its side opposite to the bottom wall 5 , the support 11 mounts a plurality of yarn guides 7 and 8 that project into the heating channel 2 . The yarn guides 7 extend in two parallel lines and in spaced relationship in the longitudinal direction, and form between them a yarn guide track 6 . 1 . Also, the yarn guides 7 each have a yarn guide edge 9 , which faces an advancing yarn 19 . 1 . In this connection, the yarn guide track 6 . 1 constitutes the guide track, through which the yarn 19 . 1 advances in the heating channel 2 . The yarn guides 7 are arranged with their yarn guide edges 9 alternatingly on opposite sides, so that the yarn guide track 6 . 1 is of zigzag form.
The yarn guides 8 extend in two lines parallel to the yarn guides 7 , and form a yarn guide track 6 . 2 . Likewise, the yarn guides 8 are arranged with their guide edges 9 alternatingly on opposite sides in spaced relationship with one another, so that they form a zigzag yarn guide track 6 . 2 . In the illustrated embodiment, the yarn guide tracks 6 . 1 and 6 . 2 are formed by a different number of yarn guides 7 and 8 . In the yarn guide track 6 . 2 , the inlet region of the heater comprises a plurality of yarn guides 8 arranged one after another at short intervals, with no yarn guides in the center region. In comparison therewith, the yarn guide track 6 . 1 is formed by a number of yarn guides 7 which are arranged offset from one another in an evenly spaced relationship.
FIG. 2 is an end view of the yarn guides 7 and 8 . The yarn guides 7 and 8 each have an L-shape yarn guide edge 9 . The L-shaped yarn guide edge 9 is used to achieve a guidance of the yarn that is defined by its spacings from the side walls 3 and 4 , as well as from the bottom wall 5 . The yarn guide edges 9 of the yarn guides 7 and 8 define a yarn advancing plane 17 , which is substantially parallel to the bottom wall 5 . With that, the yarns 19 . 1 and 19 . 2 advance through the heating channel 2 at one level.
In the embodiment shown in FIGS. 1 and 2, the yarn guides are projectingly mounted to the support 11 . Preferably, the yarn guides are made from a ceramic material. However, it is also possible to use pin-shaped yarn guides with a metallic surface.
In the present embodiment, the arrangement of the yarn guides 7 and 8 is selected such that different yarn guide tracks 6 . 1 and 6 . 2 form in the heating channel. It is preferred to use a heating device of this kind for heat treating yarns, which are subsequently combined to one yarn and wound.
In the production of textured individual yarns, it is preferred to use the arrangement of the yarn guides 7 and 8 , as shown in FIGS. 3 and 4. In this embodiment, components with the same functions have been provided with the same numerals. In its basic construction, the heating device is identical with the previously described embodiment. To this extent, the foregoing description is herewith incorporated by reference.
In the case of the heating device shown in FIGS. 3 and 4, a profiled rail 14 is inserted as a support into the heating channel 2 . The profiled rail 14 defines two guide channels 15 and 16 extending in the longitudinal direction of the heating device, with each being defined by profiled walls 12 and 13 . The profiled rail 14 is likewise open to the open side of the heating channel. The profiled walls 12 and 13 lie against the side walls 3 and 4 of the channel 2 . The guide channels 15 and 16 of the profiled rail 14 are separated from each other by a center ridge 18 .
In the guide channel 15 of the profiled rail 14 , the yarn guides 7 are arranged in spaced relationship, one after another in one plane which lies in the longitudinal direction. The yarn guide edges 9 of the adjacent yarn guides 7 are arranged offset from one another on opposite sides, so as to form a zigzag yarn guide track 6 . 1 in the guide channel 15 .
In the guide channel 16 , the yarn guides 8 are arranged in one line offset from the yarn guides 7 . However, it is also possible to arrange the yarn guides 8 symmetrically to the yarn guides 7 . The yarn guides 8 are likewise arranged in spaced relationship alternatingly with their yarn guide edges 9 on opposite sides in such a manner that the yarn guide track 6 . 2 is zigzagged. Thus, the yarn guides 7 and 8 describe a yarn advancing plane 17 , which is defined by the yarn guide edges 9 of the yarn guides 7 and 8 . The yarn advancing plane 17 extends substantially parallel to the channel bottom 5 .
In the case of the illustrated yarn guides 7 and 8 , the surface of the yarn guides facing the yarn is rounded, so that during its advance over the yarn guide edge 9 , the yarn is able to extend gently over the surfaces thereof. The yarn guide may be L-shaped in cross section, so that it has the shape of a boot. The boot shape of the yarn guide 7 or 8 is defined by an upright portion and a horizontal instep portion. To mount the yarn guides, it is possible to provide recesses in the profiled rail 14 , so that the yarn guides 7 or 8 can be exchangeably inserted into the profiled rail 14 .
In the described embodiments, the support 11 or profiled rail 14 is easy to remove from the heating channel 2 , for example, for purposes of cleaning the yarn guides, and to replace after the cleaning is completed.
In the embodiment of FIGS. 3 and 4, the profiled rail 14 is made, for example, in one piece. It is also possible to form the profiled rail 14 from two joined U-shaped individual rails. Each of the individual rails comprises a guide channel, which mounts the yarn guides. The individual rails are interconnected along their opposite longitudinal sides. An illustration of this embodiment has been omitted, since its construction can be noted from FIGS. 3 and 4, wherein the center ridge 18 would be formed by the joined longitudinal sides of the individual rails.
When heating devices of this kind are used, the heater 1 is surrounded by an insulating material. On the open side of the heating channel, a cover connected to the heater 1 and the insulating material is provided, so as to avoid a great loss of heat. For the sake of clarity, these components are not shown in the illustrated embodiments and not described in greater detail.
To heat parallel advancing yarns differently, it is also possible to construct the yarn guides 7 and 8 with different yarn guide edges 9 , so that they define a yarn advancing plane that is oblique relative to the channel bottom wall 5 . It would thus be possible to guide the yarns through the heating channel at different levels.
In the foregoing embodiments, the arrangement of the yarn guides and the configuration of the yarn guide tracks are exemplary. Basically, any arrangement of the yarn guides within the heating channel is possible to obtain symmetrical or asymmetrical yarn guide tracks. Likewise, the number of the yarn guide tracks is not limited to two. Thus, it would be possible to guide side by side more than two yarns through the heating channel. | A heating device for heating at least one advancing yarn in a texturing machine, wherein the body of the heating device defines an elongate heating channel. The heating channel accommodates an exchangeable support which mounts a plurality of yarn guides which are arranged inside the heating channel for forming a plurality of adjacent yarn guide tracks for guiding a plurality of yarns in such a manner that the yarns advance in a yarn advancing plane extending at a predetermined distance from the bottom wall of the heating channel. | 3 |
BACKGROUND AND SUMMARY OF THE INVENTION
This invention relates generally to electroluminescent lamp drivers and, more particularly, to a DC to AC switching circuit for driving a load exhibiting capacitive characteristics.
An electroluminescent (EL) lamp is an increasingly common light emitting device utilized for providing display backlighting in many types of battery powered devices such as watches, PDAs, and cellular telephones, for example. The electrical loading characteristics of an EL lamp are substantially capacitive. To excite an EL lamp into luminescence, a relatively high voltage AC signal must be applied to the terminals thereof. Typically, the AC signal will exhibit an oscillation frequency within the range of 200-400 Hz with a peak-to-peak amplitude of 100-200 volts. To generate a high voltage AC signal from the relatively low DC voltage typically supplied by a battery, it is common to step the low battery voltage up to a relatvely high DC voltage utilizing a common boost converter. The DC voltage provided at the output of the boost converter is then converted to an AC voltage using any of a number of well known switching techniques, The H-bridge represents one such switching circuit.
Several prior art methods are known for converting a DC voltage to the AC voltage required for driving an electroluminescent lamp. Exemplary of the prior art is that described in U.S. Pat. Nos. 4,527,096 to Kindlmann and 5,463,283 to Sanderson. Kindlmann teaches a circuit for efficiently driving an EL lamp utilizing relatively few components. However, in the Kindlmann circuit, relatively large current pulses are delivered directly from an inductive element into the capacitve EL lamp. These large current spikes produce a series of small voltage steps across the EL lamp. From a reliability standpoint, these large current spikes could shorten the life of the EL lamp. The Sanderson patent discloses an alternate approach in which a common boost converter generates a relatively high voltage DC supply which is utilized to sequentially charge and discharge the EL lamp by means of a constant current through an H-bridge switching circuit. Therefore, in contrast to delivering energy through a series of large current spikes, as taught by Kindlmann, Sanderson's approach delivers energy to the EL lamp by means of a constant current, thereby extending the life of the EL lamp. Nevertheless, the Sanderson circuit is disadvantageous in that his use of current from the high voltage supply to remove charge from the capactive EL lamp will result in significantly higher power consumption when compared to the Kindlmann circuit.
It would therefore be advantageous to provide a switching circuit in accordance with the present invention for delivering energy from a high-voltage DC supply to an EL lamp utilizing a constant current flow and an improved method for discharging the capacitive EL lamp to thereby achieve significant reductions in the average current consumption from the high voltage supply.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a detailed schematic diagram of a DC to AC switching circuit for driving an EL lamp, in accordance with a first embodiment of the present invention.
FIG. 2 is a waveform diagram illustrating typical waveforms associated with the circuit of FIG. 1.
FIG. 3A is a schematic diagram illustrating a first embodiment of the current conduction portion of the circuit of FIG. 1.
FIG. 3B is a schematic diagram illustrating a second embodiment of the current conduction portion of the circuit of FIG. 1.
FIG. 3C is a schematic diagram illustrating a third embodiment of the current conduction portion of the circuit of FIG. 1.
FIG. 3D is a schematic diagram illustrating a fourth embodiment of the current conduction portion of the circuit of FIG. 1.
FIG. 3E is a schematic diagram illustrating a fifth embodiment of the current conduction portion of the circuit of FIG. 1.
FIG. 4 is a detailed schematic diagram of a DC to AC switching circuit for driving an EL lamp, in accordance with a second embodiment of the present invention.
FIG. 5 is a waveform diagram illustrating typical waveforms associated with the circuit of FIG. 4.
FIG. 6 is a detailed schematic diagram of a DC to AC switching circuit for driving an EL lamp, in accordance with a third embodiment of the present invention.
FIG. 7 is a detailed schematic diagram of a DC to AC switching circuit for driving an EL lamp, in accordance with a fourth embodiment of the present invention.
FIG. 8 is a detailed schematic diagram of a DC to AC switching circuit for driving an EL lamp, in accordance with a fifth embodiment of the present invention.
FIG. 9 is a detailed schematic diagram of a DC to AC switching circuit for driving an EL lamp, in accordance with a sixth embodiment of the present invention.
FIG. 10 is a detailed schematic diagram of a DC to AC switching circuit for driving an EL lamp, in accordance with a seventh embodiment of the present invention.
FIG. 11 is a detailed schematic diagram of a DC to AC switching circuit for driving an EL lamp, in accordance with an eighth embodiment of the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring now to FIG. 1, there is shown a schematic block diagram of a switching circuit in accordance with a first embodiment of the present invention. A voltage source 100 provides a DC voltage at input rail V HV relative to a DC reference 101. Output terminals V A and V B are connected to an electroluminescent lamp 102 or other substantially capacitive load. A first switch SW1 is connected between the voltage rail V HV and output terminal V A . When a first output signal C1 is issued by a switch control and driver circuit 103, switch SW1 will be turned on, and a currrent I 1 will flow from the DC voltage rail V HV into the output terminal V A . A second switch SW2 is connected between the DC voltage rail V HV and output terminal V B . When a second output signal C2 is issued by switch control and driver circuit 103, switch SW2 will be turned on, and a current I 2 will flow from the DC voltage rail V HV into the output terminal V B .
A first current conduction circuit 110, comprising a switch SW3, a current source 111, and a rectifying diode 112, is connected between output terminal V A and DC reference 101. When signal C3 is issued by switch control and driver circuit 103, a constant current corresponding to the current provided by current source 111 will flow from output terminal V A into the first current conduction circuit 110, provided that the voltage at output terminal V A is substantially higher than the DC reference 101. In this case rectifier 112 will be non-conducting. If the voltage at output terminal V A should drop to a level less than that of DC reference 101, rectifying means 112 will begin conducting current, thus reducing the current through switch SW3. Rectifier 112, together with switch SW3 further prevents the voltage at output terminal V A from dropping to a level that is significantly less than that of the DC reference 101.
A second current conduction circuit 120, comprising a switch SW4, a current source 121, and a rectifying diode 122, is connected between output terminal V B and DC reference 101. When signal C4 is issued by switch control and driver circuit 103, a constant current corresponding to the current provided by current source 121 will flow from output terminal V B into the second current conduction circuit 120, provided that the voltage at output terminal V B is substantially higher than DC reference 101. In this case rectifier 122 will be non-conducting. If the voltage at output terminal V B should drop to a level less than that of DC reference 101, rectifier 122 will begin conducting current, thus reducing the current through switch SW4. Rectifier 122, together with switch SW4, further prevents the voltage at output terminal V B from dropping to a level that is significantly less than that of the DC reference 101.
The switch control and driver circuit 103 periodically issues output signals C1, C2, C3, and C4 synchronously with a clock which can be generated either internally or externally. Referring now to FIG. 2, there is shown a waveform diagram which exhibits the timing characteristics of signals C1, C2, C3, and C4 generated by switch control and driver circuit 103. These signals will periodically cycle switches SW1, SW2, SW3, and SW4 through four states of operation.
During the first state of operation, timing signals C1 and C4 will be issued, turning on switches SW1 and SW4, respectively. With switch SW1 on, the output terminal V A will be pulled to the potential of the input rail V HV . With SW4 turned on, current drawn from current source 121 will flow through circuit components SW4, C LAMP , and SW1. The current drawn from the input rail V HV will be equal to the current drawn from current source 121. Assuming that the charge on electroluminescent lamp 102 was initially zero, current drawn from current source 121 will cause the voltage at output terminal V B to ramp downward at a fixed rate. The voltage at output terminal V B will continue to ramp downward at a fixed rate until rectifier 122 turns on and current flow through switch SW4 ceases. When rectifier 122 turns on, the current drawn from current source 121 will flow through the rectifier 122, and the current I 1 flowing through circuit components SW4, C LAMP , and SW1 will drop to zero. With the current flow through electroluminescent lamp 102 at zero, the voltage at output terminals V A and V B will remain steady. At the end of this state of operation, the voltage across the electroluminescent lamp 102 (V A -V B ) will be substantially equal to the voltage provided by the input rail V HV .
During the second state of operation, timing signals C3 and C4 will be issued, turning on switches SW3 and SW4, respectively. With switches SW1 and SW2 turned off, current drawn from the input rail V HV will be essentially zero. With switch SW3 turned on, current drawn from current source 111 will flow through circuit components SW3, C LAMP , and rectifier 122. While current is flowing through these elements, rectifier 122 is forward biased, and the voltage at output terminal V B is slightly less than the DC reference 101. The voltage at output terminal V A will ramp downward at a rate proportional to the current provided by current source 111. When the voltage at output terminal V A falls to a potential less than the DC reference 101, rectifier 112 will turn on, and the current flow through circuit components SW3, C LAMP , and SW4 will drop to approximately zero. At the end of this state of operation, the voltage across the electroluminescent lamp 102 (V A -V B ) will be discharged to approximately zero voltage.
During the third state of operation, timing signals C2 and C3 will be issued, turning on switches SW2 and SW3, respectively. With switch SW2 on, the output terminal V B will be pulled to the potential of the input rail V HV . With switch SW3 turned on, current drawn from current source 111 will flow through circuit components SW3, C LAMP , and SW2. The current drawn from the input rail V HV will be equal to the current from current source 111. Assuming the charge on electroluminescent lamp 102 was initially zero, current from current source 111 will cause the voltage at output terminal V A to ramp downward at a fixed rate. The voltage at output terminal V A will continue to ramp downward at a fixed rate until rectifier 112 turns on. When rectifier 112 turns on, the current drawn from current source 111 will flow through the rectifier 112, and the current I 2 flowing through circuit elements SW3, C LAMP , and SW2 will drop to zero. With the current throught the electroluminescent lamp 102 at zero, the voltage at output terminals V A and V B will remain steady. At the end of this state of operation, the voltage across the electroluminescent lamp 102 (V A -V B ) will be substantially equal to the voltage provided by the input rail V HV , but will be of the opposite polarity.
During the fourth state of operation, timing signals C3 and C4 will be issued, turning on switches SW3 and SW4, respectively. With switches SW1 and SW2 turned off, current drawn from the input rail V HV will be essentially zero. With switch SW4 turned on, current drawn from current source 121 will flow through circuit components SW4, C LAMP , SW3, and rectifier 112. While current is flowing through these elements, rectifier 112 is forward biased, and the voltage at output terminal V A is slightly less than the DC reference 101. The voltage at output terminal V B will ramp downward at a rate proportional to the current provided by current source 121. When the voltage at output terminal V B falls to a value that is less than that of DC reference 101, rectifier 122 will turn on, and current through circuit components SW4, C LAMP , and SW3 will drop to approximately zero. At the end of this state of operation, the voltage across the electroluminescent lamp 102 (V A -V B ) will be discharged to approximately zero.
Implementation of the switch control and driver circuit 103 is well within the capabilities of a person having ordinary skill in the art. This circuit consists simply of a clocked state machine with four outputs, no inputs, and four states of operation. The primary design requirement of this state machine is the use of a sufficiently low clocking frequency to allow enough time for the capacitive electroluminescent lamp 102 to substantially charge and discharge. A secondary design requirement of the switch control and driver circuit 103 is to avoid a commonly known characteristic referred to as "shoot through" or "cross conduction." This phenomena occurs when current from the DC supply rail V HV flows directly to DC reference 101 without passing through the load (e.g. through switch pair SW1, SW3 or through switch pair SW2, SW4). Although current sources 111 and 121 limit the magnitude of the "shoot through" current, minimizing or eliminating the time period during which the aforementioned switch pairs are simultaneously conducting will reduce unnecessary losses.
The first switch SW1 of the switching circuit of FIG. 1 serves to connect the output terminal V A to input rail V HV during the first state of operation. During the first state, output terminal V A will remain at a voltage level substantially equal to that of the input rail V HV . Similarly, the second switch SW2 serves to connect output terminal V B to input rail V HV during the third state of operation. Those skilled in the art will appreciate the multitude of possibilities that exist for the specific implementation of switches SW1 and SW2. Exemplary of such possibilities are MOSFET transistors, bipolar transistors, SCRs, etc.
The first current conduction circuit 110 of FIG. 1 serves to conduct current from output terminal V A to the DC reference 101. Similarly, the second current conduction circuit 120 serves to conduct current from output terminal V B to the DC reference 101. The manner in which current is conducted from the output terminals V A and V B is dependent upon the present state of operation and the voltage potential present at each of the output terminals. Functionally, the first current conduction circuit 110 and the second current conduction circuit 120 are identical with the exception of the operational states being two states out of phase. The following description further delineates the behavior of the first conduction circuit 110 in each of the four operational states. During the first state of operation, switch SW1 is on, and the voltage at output terminal V A is substantially equal to that of the input rail V HV . With output terminal V A connected to input rail V HV , first current conduction circuit 110 should act as an open circuit throughout the first state of operation. Thus, current flowing into first current conduction circuit 110 will be substantially equal to zero throughout the first state of operation. During the second state of operation, when switches SW3 and SW4 are on, first current conduction circuit 110 serves to conduct a substantially constant current from output terminal V A . While output terminal V A remains substantially greater than DC reference 101, first current conduction circuit 110 will continue to draw a substantially constant current from output terminal V A . When the voltage of output terminal V A drops to a value slightly below that of DC reference 101, rectifier 112 will begin to conduct, and current flow from output terminal V A will drop to a value substantially equal to zero. During a third state of operation, switch SW2 is on, and the voltage at output terminal V B is substantially equal to that of the input rail V HV . Similar to the second state of operation, first current conduction circuit 110 serves to conduct a substantially constant current from the output terminal V A during the third state of operation. While the voltage at output terminal V A remains substantially greater than that of the DC reference 101, the first current conduction circuit 110 will continue to draw a substantially constant current from output terminal V A . When the voltage at output terminal V A drops to a value slightly below that of DC reference 101, rectifier 112 will begin to conduct, and current flow from output terminal V A will drop to a value substantially equal to zero. During a fourth state of operation, when switches SW3 and SW4 are on, current conduction circuit 120 will be pulling down on output terminal V B with a substantially constant current. Under such conditions, rectifier 112 serves to prevent the voltage at output terminal V A from dropping to a level that is substantially less than that of DC reference 101. Therefore, during the fourth state of operation, current conduction circuit 110 serves as a rectifier to maintain the voltage at output terminal V A substantially equal to that of DC reference 101.
Although one embodiment of the first and second current conduction circuits 110 and 120 has been illustrated in FIG. 1, it will be appreciated by those skilled in the art that other embodiments are possible. FIGS. 3A-E illustrate some of those other embodiments. For example, FIG. 3A illustrates a switch SW1, a current source 11, and a passive rectifier D1, as employed in the first embodiment of the present switching circuit. FIG. 3B illustrates a switch SW1, a current source 11, a first passive rectifier D1, and a second rectifier D2. In this embodiment of current conduction circuit 110, switch SW1 is closed during the second and third states of operation. FIG. 3C illustrates a switch SW1, a current source 11 with a corresponding enable signal EN, and a passive rectifier D1. In this embodiment, switch SW1 is closed, and current source 11 is enabled during the second and third states of operation. During the first and fourth states of operation switch SW1 is open, and current source 11 is disabled. FIG. 3D illustrates a current source 11, a corresponding enable signal EN, and a passive rectifier D1. In this embodiment, current source 11 is enabled during the second and third states of operation. FIG. 3E illustrates a current source 11, a corresponding enable signal EN, and a switch SW1 that serves as an active rectifier. In this embodiment, current source 11 is enabled during the second and third states of operation. If the voltage across current source 11 is substantially zero, current source 11 is disabled, and synchronous switch SW1 is turned on. In the fourth state of operation, current source 11 is disabled, and switch SW2 is open. Although several specific embodiments of first and second current conduction circuits 110 and 120 have been described and shown, a multitude of other possibilities exist which exhibit the same functional characteristics as those illustrated. Furthermore, although the embodiments of the first and second current conduction circuits of FIGS. 3A-3E have been illustrated with constant current sources, resulting in a ramp waveform across capacitive load 102, those persons skilled in the art could readily replace the constant current sources with variable current sources to generate alternative waveform shapes across the capacitive load 102.
The embodiment of the present switching circuit illustrated in FIG. 1, when compared to a previously mentioned prior art circuit, achieves a reduction in average supply current of approximately 50%. Furthermore, this embodiment exhibits the advantageous characteristic of constant current delivery to the electroluminescent lamp 102. Such an approach will extend the life of lamp 102, while minimizing power dissipation. The primary disadvantage of the switching circuit of FIG. 1 is the significant amount of delay time between the discharging and charging of electroluminescent lamp 102. This delay time will introduce a "flat spot" in the rising and falling waveforms of voltage across the electroluminescent lamp 102.
Referring now to FIG. 4, there is shown a schematic block diagram of a switching circuit in accordance with a second emodiment of the present invention which serves to eliminate the "flat spot" characteristic exhibited by the switching circuit of FIG. 1. The operation of the circuit of FIG. 4 is identical to that of the circuit of FIG. 1, with the exception of control signal timing. In the circuit of FIG. 1, the control signals C1, C2, C3, and C4 are generated by the switch control and driver circuit 103 independent of any inputs. In the circuit of FIG. 4, a modified switch control and driver circuit 203 generates output signals C1, C2, C3, and C4 in response to input signals IN1 and IN2. The first input signal IN1 serves to initiate a transition between the second and third states of operation. The second input signal IN2 serves to initiate a transition between the fourth and first states of operation. As an alternative approach, a single input may be utilized for initiating both the second-to-third state transition and the fourth-to-first state transition. The remaining state transitions are initiated in response to a clock, independent of the input signals, in a manner similar to the way those state transitions are initiated in the switching circuit of FIG. 1.
A sense and compare circuit 200 of FIG. 4 serves to monitor the voltages at the first and second output terminals V A and V B to generate two output signals connected to the IN1 and IN2 inputs, respectively, of switch control and driver circuit 203. Comparator 201 serves to monitor the voltage at the first output terminal V A . At the initiation of the second state of operation, the voltage at output terminal V A is relatively high. Throughout the second state of operation, the voltage at the output terminal V A decreases at a fixed rate toward zero. When the voltage at the output terminal V A passes through a first reference voltage V REF1 that is typically near zero, comparator 201 will issue signal IN1. In response to the issuance of signal IN1, switch control and driver circuit 203 will terminate the second state of operation and initiate the third state of operation. Comparator 202 serves to monitor the voltage at the second output terminal V B . At the initiation of the fourth state of operation, the voltage at output terminal V B is relatively high. Throughout the fourth state of operation, the voltage at the output terminal V B will decrease at a fixed rate toward zero. When the voltage at the output terminal V B passes through a second reference voltage V REF2 that is also typically near zero, comparator 202 will issue signal IN2. In response to the issuance of signal IN2, switch control and driver circuit 203 will terminate the fourth state of operation and initiate the first state of operation.
As in the case of the switching circuit of FIG. 1, implementation of switch control and driver circuit 203 is well within the capabilities of those persons having ordinary skill in the art. Switch control and driver circuit 203 simply consists of a clocked state machine having four outputs, two inputs, and four states of operation. The transition from the first state to the second state and the transition from the third state to the fourth state is initiated in response to a clock. The transition from the second state to the third state and the transition from the fourth state to the first state is initiated in response to the two input signals. As in the case of the switching circuit of FIG. 1, some design precautions should be taken during state transitions to avoid the commonly known "shoot through" or "cross conduction" phenomena.
Referring now to FIG. 5, there is shown a waveform diagram illustrating the timing characteristics of signals C1, C2, C3, and C4 generated by the switch control and driver circuit 203. This waveform diagram differs from that of FIG. 2 in the duration of the second and fourth states of operation. The switching circuit of FIG. 4 transitions from the second to the third state and from the fourth to the first state immediately following the discharge of the capacitive load 102. This immediate transition from one state to another serves to eliminate the "flat spot" characteristics of the switching circuit of FIG. 1.
In the embodiment of the invention illustrated in FIG. 4, sense and compare circuit 200 serves to individually monitor output terminals V A and V B . Referring now to FIG. 6, there is shown a third embodiment of the present invention in which the sense and compare circuit 200 of FIG. 4 has been replaced with a modified sense and compare circuit 300 which utilizes differential voltage sensing means. A differential amplifier 303 serves to monitor the differential voltage between output terminals V A and V B to generate a sense voltage V C . Sense voltage V C is compared to a first reference voltage V REF1 utilizing a first comparator 301 to generate input signal IN1 to the switch control and driver circuit 203. Similarly, a second comparator 302 is utilized to generate input signal IN2 by comparing sense voltage V C to a second reference voltage V REF2 . Typically, the first reference voltage V REF1 and the second reference voltage V REF2 will have values close to zero. In such an arrangement, output signals IN1 and IN2 will be issued as the differential voltage across the output terminals V A and V B approaches zero.
In the embodiment of FIG. 6, sense and compare circuit 300 serves to differentially monitor the voltage between output terminals V A and V B to generate input signals IN1 and IN2. Referring now to FIG. 7, there is shown a fourth embodiment of the present invention in which the sense and compare circuit 300 of FIG. 6 has been replaced with a modified sense and compare circuit 400 which utilizes a current sensing means. An amplifier 403 provides a current sensing function for monitoring current I C to generate a proportional sense voltage V C . Many well known techniques exist in the prior art for sensing a current and generating a proportional voltage. Exemplary of such techniques are the current sense resistor and the current sense coil. Sense voltage V C is compared to a first reference voltage V REF1 utilizing a first comparator 401 to generate input signal IN1 to the switch control and driver 203. Similarly, a second comparator 402 is utilized to generate input signal IN2 by comparing sense voltage V C to a second reference voltage V REF2 . As mentioned in the foregoing descriptions of previous embodiments of the present invention, as the voltage across capacitive load 102 discharges toward zero, current flow through current conduction circuits 110 and 120 is also reduced toward zero. Therefore, voltage references V REF1 and V REF2 are typically set to a value near zero to correspondingly detect zero current through the load 102. Although the diagram of FIG. 7 illustrates sense and compare circuit 400 monitoring current I C through the capacitive load 102, sense and compare circuit 400 could alternatively monitor the current flow through current conduction circuits 110 and 120 while still providing proper operation of the circuit of the present invention.
In the previously described fourth embodiment of the present invention, sense and compare circuit 400 serves to monitor the current through capactive load 102 to generate input signals IN1 and IN2. Referring now to FIG. 8, there is shown a fifth embodiment of the present invention which utilizes an alternative sense and compare circuit 500 employing a pair of current sensing amplifiers. Amplifier 503 provides a current sensing function for monitoring current flowing into current conduction circuit 110 to generate a first sense voltage V C . Sense voltage V C is compared to a first voltage reference V REF1 by comparator 501 to generate control signal IN1. Similarly, amplifier 504 provides current sensing function for monitoring current flowing into current conduction circuit 120 to generate a second sense voltage V D . Sense voltage V D is compared to a second voltage reference V REF2 by comparator 502 to generate control signal IN2. As with the previously described fourth embodiment, voltage references V REF1 and V REF2 are typically set to a value near zero corresponding to approximately zero current through either of current conduction circuits 110 and 120. Although the embodiment of FIG. 8 is illustrated with the outputs of comparator 501 and comparator 502 connected to the respective IN1 and IN2 inputs of switch control and driver circuit 203, the output of comparator 501 could alternatively drive the IN2 input with comparator 502 driving the IN1 input. Such a modification, together with corresponding adjustments in the voltage references V REF1 and V REF2 would still provide proper operation.
Referring now to FIG. 9, there is shown a schematic block diagram in accordance with a sixth embodiment of the present invention. In each of the previously described second, third, fourth, and fifth embodiments, switch control and driver circuit 203 initiates state transitions in response to two input signals IN1 and IN2. The embodiment of FIG. 9 utilizes a modified switch control and driver circuit 303 which initiates state transitions in response to a single input IN1. As with previous embodiments, the transition between the first and second states of operation and the transition between the third and fourth states of operation are initiated in response to a clock signal. Switch control and driver circuit 303 further initiates the transition between the second and third states of operation and between the fourth and first states of operation, in response to the single input IN1. Sense and compare circuit 600 serves to monitor the differential voltage between output terminals V A and V B and generate a single output signal IN1 connected to the input of switch control and driver circuit 303. An amplifier 602 monitors the differential voltage between output terminals V A and V B and generates an output voltage V C . Output voltage V C is compared to a voltage reference V REF1 by a comparator 601. The output of comparator 601 corresponds to the output of the sense and compare circuit 600. The output of sense and compare circuit 600 is connected to the input of switch control and driver circuit 303. As with previous embodiments, voltage reference V REF1 is typically near zero, corresponding to signal IN1 being issued as the differential voltage V A -V B passes through zero. The signal IN1 is thus being utilized for initiating the aforementioned state transitions.
In the previously described sixth embodiment of the present invention, sense and compare circuit 600 serves to monitor the differential voltage between output terminals V A and V B to generate a single input signal IN1 to switch control and driver circuit 303. Referring now to FIG. 10, there is shown a seventh embodiment of the present invention wherein said sense and compare circuit 600 has been replaced with a modified sense and compare circuit 700 which utilizes current sensing to generate a single output signal. Amplifier 702 provides current sensing for monitoring current I C to generate a proportional sense voltage V C . Sense voltage V C is compared to reference voltage V REF1 utilizing comparator 701 to generate input signal IN1 to switch control and driver circuit 303. As mentioned hereinabove in the description of previous embodiments of the present invention, as the voltage across capacitive load 102 discharges toward zero, current flow through current conduction circuits 110 and 120 also decreases toward zero. Therefore, voltage reference V REF1 is typically set to a value near zero to correspondingly detect zero current through the load. Although the diagram of FIG. 10 illustrates sense and compare circuit 700 monitoring current I C through the capacitive load 102, sense and compare circuit 700 could alternatively monitor the current flow through current conduction circuit 110 or current conduction circuit 120 while still providing proper operation of the present invention.
The previously described embodiments utilize a voltage source 100 to generate the voltage on the DC input rail V HV . Those skilled in the art will readily recognize that the voltage source 100 in the previously described seven embodiments of the present invention can be easily replaced with an alternative DC voltage source, such as a DC-to-DC converter, for example.
Referring now to FIG. 11, there is shown a schematic block diagram in accordance with an eighth embodiment of the present invention. A DC-to-DC converter 800 steps up a relatively small voltage source 801, such as a battery, to the higher voltage required at the input supply rail V HV . A first output terminal V A and a second output terminal V B are connected to the first and second terminals, respectively, of capacitive load 102, which may comprise an electroluminescent lamp, for example. A first switch SW1 is connected between input rail V HV and the first output terminal V A . Control signal C1 turns on switch SW1, thus connecting output terminal V A to input supply rail V HV . Similarly, a second switch SW2 is connected between input rail V HV and the second output terminal V B . Control signal C2 turns on switch SW2, thus connecting output terminal V B to input supply rail V HV . Switches SW1 and SW2 may be implemented through the use of any of a number of well known switching devices, such as MOSFET transistors, bipolar transistors, SCRs, etc. The series connection of a third switch SW3 and a first transistor current source Q2 is connected between the first output terminal V A and the DC reference 101. Control signal C3 turns on switch SW3, thereby allowing transistor current source Q2 to pull down on the first output terminal V A with a substantially constant current. Similarly, the series connection of a fourth switch SW4 and a second transistor current source Q3 is connected between the second output terminal V B and the DC reference 101. Control signal C4 turns on switch SW4, thereby allowing transistor current source Q3 to pull down on the second output terminal V B with a substantially constant current. Implementation of transistor current sources Q2 and Q3 can be accomplished through the use of many well known devices, such as MOSFET transistors and bipolar transistors. Current reference 802 together with transistor Q1 appropriately biases current sources Q2 and Q3. A multitude of alternative techniques exist for appropriately setting the bias of transistor current sources Q2 and Q3. A pair of rectifying diodes D2 and D3 are connected in parallel with transistor current sources Q2 and Q3, respectively. Rectifying diode D2 serves to provide a low impedance connection to DC reference 101 when the output of current source transistor Q2 should be pulled to a potential below DC reference 101. Similarly, rectifying diode D3 serves to provide a low impedance connection to DC reference 101 when the output of current source transistor Q3 should be pulled to a voltage below DC reference 101. In an implementation utilizing an integrated circuit, diodes D2 and D3 may comprise the bulk diode associated with transistors Q2 and Q3. Furthermore, in a scenario in which current sources Q2 and Q3 are implemented using MOSFET transistors configured as current sources, the MOSFET transistors can further act as synchronous switches when the polarity of the voltage present on the output of the current sources is driven to a voltage less than that of DC reference 101.
Switch control and driver circuit 203 periodically issues output signals C1, C2, C3, and C4. During a first state of operation, control signals C1 and C4 are issued to turn on switches SW1 and SW4, respectively. During the first state of operation, transistor current source Q3 serves to charge lamp 102 with a substantially constant current. At the termination of the first state of operation, a differential voltage V A -V B that is substantially equal to the voltage supplied by the input voltage rail V HV will be applied to electroluminescent lamp 102. During a second state of operation, control signals C3 and C4 are issued to turn on switches SW3 and SW4, respectively. Also during the second state of operation, transistor current source Q2 serves to discharge electroluminescent lamp 102 with a substantially constant current. At the termination of the second state of operation, the differtial voltage V A -V B across lamp 102 will be substantially equal to zero. During a third state of operation, control signals C2 and C3 are issued to turn on switches SW2 and SW3, respectively. During the third state of operation, transistor current source Q2 serves to charge electroluminescent lamp 102 with a substantially constant current. At the termination of the third state of operation, a differential voltage V B -V A substantially equal to the voltage supplied by the input rail V HV will be applied to lamp 102. During a fourth state of operation, control signals C3 and C4 are issued to turn on switches SW3 and SW4, respectively. During the fourth state of operation, transistor current source Q3 serves to discharge electroluminescent lamp 102 with a substantially constant current. At the termination of the fourth state of operation, the differential voltage V B -V A across lamp 102 will be substantially equal to zero. Switch control and driver circuit 203 periodically cycles through the aforementioned four states of operation in response to a clock signal generated either internally or externally. Additional care should be taken when transitioning between the four states of operatiion to avoid the commonly known "shoot through" or "cross conduction" phenomena mentioned hereinabove in connection with the other embodiments of the present invention.
Although the previously described switch control and driver circuit 203 can be implemented with no input signals, input signals IN1 and IN2 are utilized to eliminate the presence of a "flat spot" in the differential voltage across lamp 102. This "flat spot" occurs when the differential voltage V A -V B remains approximately equal to zero for a substantial length of time during the second and fourth states of operation. Comparator 208 serves to monitor the voltage at the first output terminal V A through switch SW3, which will be on during the second state of operation. At the initiation of the second state of operation, the voltage at the output terminal V A is relatively high. Throughout the second state of operation, the voltage at the output terminal V A decreases at a fixed rate toward zero. When the voltage at the output terminal V A passes through a first reference voltage V REF1 that is typically near zero, comparator 208 will assert signal IN1. In response to the assertion of signal IN1, switch control and driver circuit 203 will terminate the second state of operation and initiate the third state of operation. Comparator 209 serves to monitor the voltage at the second output terminal V B through switch SW4 which will be on during the fourth state of operation. At the initiation of the fourth state of operation, the voltage at output terminal V B is relatively high. Throughout the fourth state of operation, the voltage at the output terminal V B decreases at a fixed rate toward zero. When the voltage at the output terminal V B passes through a second reference voltage V REF2 , also typically near zero, comparator 209 will issue signal IN2. In response to signal IN2, switch control and driver circuit 203 will terminate the fourth state of operation and initiate the first state of operation. The specific implementation of switch control and driver circuit 203 is relatively simple to one skilled in the art.
Although the previous embodiments have been described utilizing a single supply polarity in which the DC input rail voltage V HV is greater than the DC reference, those skilled in the art will readily recognize that the polarity of the previously described embodiments may be reversed to utilize a supply voltage source that is of negative polarity with respect to the reference. Implementing such a polarity reversal simply involves the reversal of the aforementioned voltage sources, current sources, and rectifiers.
In each of the previously described embodiments of the present invention, a DC to AC switching circuit has been disclosed for driving a capacitive load comprising an electroluminescent lamp 102. It will be readily appreciated that other loads, such as piezoelectric transducers, which exhibit primarily capacitive loading characteristics, may also be employed.
Several embodiments have been described above for implementing an improved DC to AC switching circuit. The novel approach of this switching circuit demonstrates constant current delivery to a capacitive load while realizing substantial reductions in supply current. Although the present invention has been described with reference to specific embodiments, it will be appreciated that various modifications may be made within the scope of the invention. | A switching circuit is provided for converting a DC voltage to an AC voltage required for driving an electroluminescent lamp. The switching circuit charges and discharges the electroluminescent lamp with a substantially constant current to thereby reduce peak currents and extend lamp life. A constant current discharge feature of the switching circuit results in a significant reduction in current consumption. | 8 |
BACKGROUND OF INVENTION
The present invention relates generally to clips for retaining rods associated with vehicle closures.
For vehicle closures that open by swinging upward, it is usually desirable to provide some type of mechanical assistance for opening and holding such closures in an open position. For example, a torque rod counterbalance system may be employed since it is a cost-effective and reliable type of counterbalance system, and also because it is not susceptible to temperature variations as are other types of counterbalance systems.
One place where such torque rod counterbalance systems may be employed are passenger car deck lids that cover trunk openings. The torque rod engages the deck lid hinge and is pre-loaded with torque to counterbalance the weight of the deck lid and allow for initial lid movement upon release of a latch. One or more torque rods may be employed to engage the pair of deck lid hinges. The nature of torque rod counterbalance systems traditionally require the torque rods to be installed after the vehicle paint process is complete and the vehicle is in a general assembly area for further installation of other components. This is done because, if they are wound up (pre-stressed) in position prior to (and during) the vehicle painting process, the torque rods will lose some of the initial toque pre-stress due to the heat of the paint process. Also, it is undesirable to create stresses in the deck lid prior to (and during) paint processing, which can occur if the torque rods are pre-stressed during paint processing.
On the other hand, there are assembly process reasons that make it desirable to mount the torque rods to the vehicle prior to paint operations. Since it is still desirable to assure that the torque rods are not pre-stressed during paint operations, some means to retain the unstressed torque rods in position in the vehicle during paint operations is desired. Preferably, this means is relatively simple, quick, reliable and inexpensive since the torque rods will still have to undergo final assembly steps where they are wound up (pre-stressed) and engaged with the deck lid hinges after the paint operations are completed.
Some have attempted to provide such a means by employing a positive retention torque rod retaining clip. These clips typically include tabs that are plastically bent (crimped) to retain the torque rod in position during paint operations. But these devices are undesirable in that they require a relatively high insertion force and have been known to accidentally release the torque rods prior to being assembled to the final vehicle location. Thus, the clips tend to be less reliable as a retention method than is desirable. Also, the clips may be out of position at the time of torque rod insertion, so a two-hand operation (one to hold the clip in the correct position and one to hold the rod) is needed.
SUMMARY OF INVENTION
An embodiment contemplates a self-engaging rod retaining clip assembly for retaining a rod. The rod retaining clip assembly comprises a vehicle closure support and a rod retaining clip. The vehicle closure support component includes a main body defining an arcuate-shaped rod channel having a rod channel opening, and a clip support arm extending from the main body adjacent to the rod channel and the rod channel opening, the clip support arm having a first side and an opposed second side and including an arm pivot hole recessed in the first and second sides. The rod retaining clip includes a clip main body having a rod retention flange extending from the clip main body outside of the rod channel when the rod retaining clip is in a pre-rod installation position; a rod pivoting flange extending from the clip main body across a portion of the rod channel opening when the rod retaining clip is in the pre-rod installation position, with the clip main body, the rod retention flange and the rod pivoting flange defining a rod recess that is shaped to receive a rod therein; a pair of clip retention flanges extending from the main body and defining an arm slot therebetween, the clip retention flanges each having a hold-open portion where a width of the arm slot between the hold-open portions is about equal to a width of the support arm, a clip securing portion where the width of the arm slot between the clip securing portions is less than the width of the arm slot between the hold-open portions, and a tapered clip spreading portion extending between the respective hold-open portions and clip securing portions; and a pivot pin pivotally securing the rod retaining clip to the clip support arm.
An embodiment contemplates a method of pre-installing a torque rod to a vehicle closure support component, the method comprising the steps of: pivotally supporting a rod retaining clip on a clip support arm of the vehicle closure support component adjacent to a rod channel with a rod pivoting flange of the rod retaining clip extending across a portion of a rod channel opening and a rod retention flange extending outside of the rod channel; maintaining the rod retaining clip in a pre-rod installation position by trapping the clip support arm between a web of the rod retention flange and hold-open portions of a pair of clip retention flanges; pressing the torque rod against the rod pivoting flange to cause the clip retention flanges to flex around the clip support arm and the rod pivoting flange to pivot into the rod channel; and pressing the torque rod further into the rod channel until the clip retention flanges no longer align with the clip support arm, allowing the clip retention flanges to snap toward each other.
An advantage of an embodiment is that the self-engaging rod retaining clip assembly minimizes assembly operator installation efforts for insertion, but positively and reliably secures vehicle torque rods during assembly plant processing. This clip is also relatively inexpensive, and quick and easy to use. No crimping (plastically bending tabs) is needed for installation, and the clip is automatically maintained in the correct position for torque rod insertion until the torque rod is actually inserted.
BRIEF DESCRIPTION OF DRAWINGS
FIG. 1 is a perspective view of a self-engaging rod retaining clip mounted on a vehicle closure support component, with the clip in a pre-rod installation (open) position.
FIG. 2 is a side view, on a reduced scale, of the clip and support component of FIG. 1 , and a rod shown initially contacting the clip in the pre-rod installation position.
FIG. 3 is a view similar to FIG. 2 , but illustrating the clip and rod in a partially installed position.
FIG. 4 is a side view similar to FIG. 2 , but illustrating the clip and rod in a fully installed (trapped) position.
FIG. 5 is a perspective view, on an enlarged scale, of the rod retaining clip assembly, in the installed position illustrated in FIG. 4 .
FIG. 6 is a perspective view of a self-engaging rod retaining clip, according to a second embodiment, mounted on the vehicle closure support component.
FIG. 7 is a side view of the clip of FIG. 6 .
FIG. 8 is a perspective view of the clip of FIG. 6 .
DETAILED DESCRIPTION
Referring to FIGS. 1-5 , a vehicle closure support component, indicated generally at 20 , is shown. The component 20 may be, for example, a hinge box or a hinge link (that drives a gooseneck strap) associated with a vehicle deck lid (not shown), or in a tailgate (not shown) or lift gate (not shown) counterbalance system. The component 20 includes a component main body 22 that defines an arcuate-shaped rod channel 24 having a rod channel opening 26 . A clip support arm 28 extends from the main body adjacent to the rod channel 24 and rod opening 26 . The support arm 28 includes an arm pivot hole 30 adjacent to the rod opening 26 , and has a first side 32 and an opposed second side 33 . A self-engaging rod retaining clip 34 is mounted on the support arm 28 . While one support component 20 and one rod retaining clip 34 are shown, there are preferably two (spaced apart) for supporting each torque rod 36 on the vehicle (not shown). However, since the second rod retaining clip 34 can essentially be the same as the first, only one is shown herein. The torque rod 36 may be conventional, if so desired, and so will not be shown in detail herein.
The self-engaging rod retaining clip 34 includes a clip main body 40 having a pair of clip pivot holes 42 coaxially aligned with the pivot hole 30 . A pivot pin 38 extends through the holes 30 , 42 , securing the clip 34 to the support arm 28 , while allowing the clip 34 to rotate relative to the support arm 28 . A rod retention flange 44 , having a central web 46 , extends from the clip main body 40 . An end 52 of the central web 46 defines an initial position retaining flange (discussed below). Also, a pair of rod pivoting flanges 48 extend from the clip main body 40 on opposed sides 32 , 33 of the support arm 28 . The rod retention flange 44 , pivoting flanges 48 and clip main body 40 define a rod recess 50 . A pair of clip retention flanges 56 also extend from the clip main body 40 on opposed sides 32 , 33 of the support arm 28 , defining an arm slot 64 .
Each clip retention flange 56 includes a rounded hold-open portion 58 on a first end 59 , a clip securing portion 60 extending adjacent to an opposed second end 61 , and a tapered clip spreading portion 62 extending between the hold-open potion 58 and the clip securing portion 60 . These portions 58 , 60 , 62 define the arm slot. A width 65 of the arm slot 64 between the hold-open portions 58 is about equal to or slightly smaller than a width 66 of the clip support arm 28 adjacent to the hold-open portion 58 when the clip 34 is in its pre-rod installation position. A width 67 of the arm slot 64 between the clip securing portions 60 is smaller than the width 65 , with a width of the arm slot 64 tapering from the width 65 to the width 67 . A pair of clip support flanges 68 may extend between the second end 61 and the pair of rod pivoting flanges 48 .
As an alternative, the tapered clip spreading portion 62 may incorporate the hold-open portion by having the clip spreading portions 62 near the first end 59 spaced apart about equal to or slightly wider than the support arm width 66 and then tapering towards each other as they extend to the clip securing portions 60 . Also, if so desired, the clip securing portions 60 may continue the taper rather than extending generally parallel to each other. This accomplishes a similar result in that the desire is to gradually flex the clip retention flanges 44 apart as the retaining clip 34 is rotated relative to the support arm 28 until the retention flanges 44 snap past the support arm 28 (discussed in more detail below).
The initial pre-paint-operations assembly of the torque rod 36 , with reference to FIGS. 1-5 , will now be described. The rod retaining clip 34 is installed onto the clip support arm 28 in its pre-rod installation position (shown in FIG. 1 ), with the end 52 of the central web 46 pressed against the clip support arm 28 and the hold-open portions 58 also pressed against the clip support arm 28 . Since the width 65 of the arm slot 64 between the hold-open portions 58 is about equal to or slightly less than the width 66 of the clip support arm 28 , the retaining clip 34 will inherently be held in this position. In the pre-rod installation position, the rod recess 50 faces outward away from the rod channel 24 , allowing for easy alignment of the torque rod 36 with this channel 24 . Positively holding the retaining clip 34 in this position makes assembly easier since the assembler knows what the clip position will be on each vehicle, and one hand will not have to be used to reposition the clip while the other hand moves the torque rod 36 into position in the recess 50 .
The initial torque rod installation continues by locating the torque rod 36 in the rod recess 50 (shown in FIG. 2 ). The assembler then pushes upward on the torque rod 36 . As the assembler pushes upward, the upward force will press the rounded hold-open portions 58 against the sides 32 , 33 of the support arm 28 , causing the clip retention flanges 56 to elastically flex away from each other. As the torque rod 36 is pushed farther upward, through the rod channel opening 26 , the clip 34 rotates relative to the clip support arm 28 . This causes the tapered clip spreading portions 60 to slide along the sides 32 , 33 , in turn causing the retention flanges 56 to gradually spread open farther (shown in FIG. 3 ). As the assembler pushes the torque rod 36 farther into the rod channel 24 , eventually the retaining clip 34 will rotate far enough that the clip securing portions 62 slide past the sides 32 , 33 of the support arm 28 , allowing the clip retention flanges 56 to spring back towards each other (shown in FIGS. 4 and 5 ). The initial torque rod installation is now complete.
With the clip securing portions 62 snapping back towards each other, the clip securing portions 62 self-engage to hold the retaining clip 34 in this fully installed (trapped) position without any further actions on the part of the assembler. Of course, the length of the rod retention flange 44 and the dimensions of the rod channel 24 are determined so that a final gap between the two is less than the diameter of the torque rod 36 . In this way, even though the torque rod 36 is not tightly retained in the rod channel 24 , the retaining clip 34 positively secures both itself and the torque rod 36 in the fully installed positions. Accordingly, this portion of the assembly process is relatively quick, simple, and reliable. Once the torque rod 36 is pushed into its desired position, the torque rod 36 will be positively retained in this desired position on the vehicle as the vehicle proceeds through paint operations—without requiring that the torque rod 36 be wound up during these operations.
After paint operations, the torque rod 36 is still positively retained in position, ready to be wound up (pre-stressed) during final assembly operations for the vehicle. After the torque rod 36 is wound up, the retaining clips 34 are no longer needed, but can be left in place since they do not interfere with the operation of the torque rod 36 or the vehicle closure. Thus, the relatively low cost of the retaining clip 34 is desirable since it is only used during a portion of the vehicle assembly process.
FIGS. 6-8 illustrate a second embodiment. Since this embodiment is similar to the first, similar element numbers will be used for similar elements, but employing 100-series numbers.
The vehicle closure support component 120 still includes a main body 122 defining a rod channel 124 having a rod channel opening 126 . A clip arm support 128 extends out and supports a self-engaging rod retaining clip 134 .
The rod retaining clip 134 still includes a clip main body 140 from which a rod retention flange 144 , having a central web 146 , and a pair of rod pivoting flanges 148 extend. The main body 140 , retention flange 144 and pivoting flanges 148 define the rod recess 150 , and the central web 146 has an end 152 for abutting the support arm 128 . A pair of clip retention flanges 156 still extend from the main body 140 , with each including a hold-open portion 158 , clip securing portion 160 and clip spreading portion that together define an arm slot 164 . Again, clip support flanges 168 may extend between the clip retention flanges 156 an the rod pivoting flanges 148 .
The rod retaining clip 134 differs from the first embodiment in that it now includes a pair of pivot pin flanges 138 , with each pivot pin flange 138 including a tapered surface. Preferably, the pivot pin flanges 138 are integral with the clip main body 140 . This clip 134 , then, may be molded from plastic, for example. The term integral, as used herein, means that the particular feature (portion) is made from the same piece of material as the area around it, forming a single monolithic part, rather than being formed separately first and then later attached by fasteners, welding, adhesive, etc. An advantage with this embodiment, then, is that no separate pin must be installed and secured in place. The clip 134 is slid over the support arm 128 with the clip oriented so that the thin side of the pivot pin flanges 138 engage the support arm 128 first. As the clip 134 slides further on, the tapered surfaces 170 will cause the clip to gradually flex open until the pivot pin flanges 138 align with and snap into a pivot hole (not shown in the second embodiment) of the support arm 128 . The clip 134 is now secured to and can pivot relative to the support arm 128 . The installation of a torque rod is the same as the first embodiment.
While certain embodiments of the present invention have been described in detail, those familiar with the art to which this invention relates will recognize various alternative designs and embodiments for practicing the invention as defined by the following claims. | A self-engaging rod retaining clip assembly for retaining a rod and a method of retaining the rod to a vehicle closure support component is disclosed. The self-engaging rod retaining clip assembly holds a rod retaining clip in a desired position on a vehicle closure support component until the rod is installed. Installing the rod includes pressing the rod against a rod pivoting flange, which causes clip retention flanges to flex outward around a clip support arm until the rod is sufficiently retained inside a rod channel in the support component. The clip retention flanges then snap towards each other to retain the clip, and hence the rod, in the support component. | 4 |
The present application relates to US. Provisional Patent Application Ser. No. 61/517,613 filed on Apr. 21, 2011 and claims priority therefrom.
The present application was not subject to federal research and/or development funding.
TECHNICAL FIELD
Generally, the invention relates to a method and machine for dewatering paper webs. More specifically, the invention is a process and machine which produces paper having more uniform fiber orientation, sheet structure and improved paper strength characteristics. The improved method and machine includes devices that are arranged in the forming or wet section of a Fourdrinier machine, hereinafter referred to as “Fourdrinier.” The devices are adjusted manually or through a computer and associated drive mechanisms.
An improved method of forming paper using a Fourdrinier is composed of a plurality of foil and vacuum assisted drainage elements that are equipped with on-the-run adjustable angle and/or height dewatering foil blades starting from a paper dryness of 0.1% and extending all the way to 5% dryness within the forming section of a Fourdrinier. The foil blade angle, height, and vacuum level are adjusted as applicable along the entire length of the Fourdrinier dewatering table until a paper dryness of 5% is achieved. These adjustments allow for control of the dewatering rate and turbulence (shear) produced from a paper dryness of 0.1% to 5% on the Fourdrinier dewatering table. Controlling drainage and shear along this entire range of dryness has a direct influence on paper fiber orientation. This has a significant influence on paper strength.
The claimed invention works in unison with the paper machine headbox shear forces to promote maximum fiber orientation in either the cross-machine or machine direction orientation of the paper. The headbox controls fiber orientation through a speed difference between its stock jet speed and the dewatering fabric speed. Once the stock jet lands on the dewatering fabric, it is operated at an overspeed compared to the dewatering fabric “rush” or the same speed “square” or an underspeed “drag” to control the orientation of the fibers during the sheet forming process. Operating the headbox in a rush or drag mode will align fibers in the machine direction which is beneficial for machine direction related strength properties in the finished paper product. Operating in a square mode will produce a maximum cross-machine direction fiber orientation of the fibers in the finished paper product which is beneficial for paper strength properties in the cross-machine direction.
The claimed invention provides control of drainage and turbulence anisoptropic shear after the headbox stock jet lands on the dewatering fabric. After the stock lands, the claimed invention is adjusted to preserve or amplify the fiber orientation characteristics produced by the headbox. In this manner, a higher quality of paper is produced with the instant process and machine. Moreover, existing machines may be retrofitted with various devices and operated in the manner disclosed herein to achieve a superior quality of paper stock.
For example, if machine direction fiber orientation is desired, the headbox jet speed is operated in a rush or drag mode to promote an initial strong machine direction alignment of the paper fibers. From here, the foil blade angles and height, along with the vacuum levels on the vacuum assisted dewatering units are adjusted to produce a high early drainage rate in the initial sheet dewatering zone (0.1% to 2% paper dryness) to immediately freeze the machine direction fiber orientation produced by the headbox. In addition to this, the foil blade angles, heights and vacuum levels are also adjusted to produce a high amount of turbulence in this paper dryness zone (0.1% to 2%). This keeps the fibers mobile and prevents entanglement allowing the headbox shear to become more effective in orientating fibers in the machine direction. After 2% paper dryness, the angle and height and vacuum levels are adjusted to gradually achieve a paper dryness of 5%. However, the foil angle and height are adjusted to achieve only moderate turbulence levels to prevent disruption of the machine direction fiber orientation achieved earlier in the sheet dewatering and forming process.
For cross-machine direction fiber alignment, the process is completely reversed. The headbox stock jet is adjusted to produce a speed difference close to zero (square mode) to promote the highest possible cross-machine direction fiber orientation. However, due to contraction created within the headbox nozzle, a certain unavoidable degree of machine direction fiber alignment is still always present in the fiber slurry when it lands on the dewatering fabric that cannot be reversed through normal Fourdrinier dewatering equipment. To break this natural machine direction fiber orientation up and produce the most random fiber orientation and highest amount of cross-machine direction fiber orientation, the claimed invention is operated as follows. First, the foil blade angles and heights along with the vacuum levels of the vacuum assisted dewatering elements are adjusted to significantly retard drainage in the early sheet forming zone (0.1% to 2% dryness). This is completely opposite of the previously described process for machine direction fiber orientation. In addition to this, the angle and height of the foil blades are adjusted to produce a very high degree of turbulence to prevent fiber entanglement and generate the most random fiber orientation possible for the highest level of cross-machine direction fiber alignment. After a dryness of 2% is achieved, the foil angle and height is adjusted to maintain this high level of turbulence all the way until a paper dryness of 5% is achieved. A very gentle early drainage along with high turbulence all the way until a dryness of 5% will create the most random fiber network resulting in the highest amount of cross-machine direction fiber alignment.
The ability of the claimed process and machine improvement to be adjusted in conjunction with shear significantly increases paper sheet strength properties such as Mullen, Burst, Bending Stiffness, or Concora (machine direction strength properties) and Ring Crush, S.T.F.I, SCT (cross machine direction strength properties) and all other strength properties associated with paper manufacturing.
In addition to this, the claimed invention and sheet forming process also improves other paper properties such as formation, smoothness, uniformity, printability, ply bond strength, and the like.
BACKGROUND OF THE INVENTION
The forming or wet section of a Fourdriner consists mainly of the head box and forming wire. Its main purpose is to generate consistent slurry, or paper pulp, for the forming wire. Several foil, suction boxes, a couch roll, and a breast roll commonly make up the rest of the forming section. The press section and dryer section follow the forming section to further remove water from the stock.
Historically, the main tools used to control paper strength have been fiber species and fiber refining energy along with the orientating shear generated by the speed difference between the headbox jet speed and the dewatering (forming) fabric speed. The first method of continuous sheet forming and dewatering was the Fourdrinier dewatering table which is still the dominant tool used for paper manufacturing today. Since the time of its invention, its impact on sheet strength has been misunderstood or vaguely understood. Also, the ability to directly influence sheet strength through changing the drainage or shear rates produced during the Fourdrinier dewatering and forming process have also been misunderstood. Past technologies such as the VID, Deltaflo or Vibrefoil have been able to adjust drainage and turbulence on the Fourdrinier table. However, these technologies have been used prior to a sheet consistency on the Fourdrinier table of 1.5% or less. The impetus behind their design was simply to generate turbulence in a very short area in an effort to improve paper uniformity (formation) which was claimed to influence sheet strength.
It has been discovered through the use of the claimed improved Fourdrinier papermaking process that controlling drainage and turbulence from a paper dryness of 0.1% to 5% on a dewatering table has a far more significant impact of fiber orientation and paper strength. In addition, the previously described methods of adjusting the headbox shear in conjunction with adjusting drainage and turbulence in this zone to control fiber orientation and paper strength up to this point been has been unknown to anyone other than the inventors of the claimed improved process.
BRIEF SUMMARY OF THE INVENTION
An improved process of Fourdrinier papermaking is used for dewatering and paper quality control and achieved in the forming end of the Fourdrinier. The process uses a plurality of gravity and vacuum assisted drainage elements that are equipped with on-the-run adjustable angle and height dewatering foil blades starting from a paper dryness of 0.1% and extending all the way to 5% dryness. The foil blade angles and heights along with vacuum level are adjusted manually or automatically along the entire length of the Fourdrinier dewatering table until paper dryness of 5% is achieved.
The claimed invention uses a series of gravity assisted drainage elements in the beginning of the Fourdrinier dewatering table. These units are the forming board and hydrofoil section that are equipped with a combination of static and adjustable angle foil blades, as well as foil blades which are height adjustable depending on the paper grade being produced. A low-vacuum section is arranged on the dewatering table after the hydrofoil section. The low-vacuum section includes vacuum assisted drainage elements which are equipped with vacuum control valves, fixed angle and angle adjustable foil blades, as well as foil blades which are height adjustable depending on the paper grade being produced. A high-vacuum section is arranged between the low-vacuum section and a couch roll.
Adjusting the angle and height of the dewatering foil blades along with the vacuum level allows for control of the dewatering rate and turbulence (shear) produced from a paper dryness of 0.1% to 5% on the Fourdrinier dewatering table. Controlling drainage and shear along this entire range of dryness in conjunction with fiber orientation shear produced by the headbox has a direct influence on paper fiber orientation. This has a significant influence on paper strength.
Adjustable dewatering technologies are typically used on the Fourdrinier table in an area directly after the forming board or within a short distance of the forming board and dry the stock to a dryness content of 3.5%. Previously, the design and operation of a Fourdrinier has been focused on fiber orientation control to improve sheet strength.
Other technologies such as the dandy roll or top dewatering machines have been used at a dryness content of 1.5% or greater. However, their purpose has simply been water removal or paper formation improvement, not fiber orientation control liked the claimed invention. Moreover, none of the existing technologies are directed towards precisely controlling fiber orientation as in the disclosed manner.
It is an object of the invention to disclose an improved process for controlling the fiber orientation of paper stock to achieve a better quality paper than is currently produced on a Fourdrinier.
It is a further object of the invention to teach a Fourdrinier having adjustable on-the-run mechanisms for adjusting the height and angle of foils or blades to easily switch over operation of the Fourdrinier to produce paper of higher quality through controlling the orientation of the fibers.
Additional objects and advantages of the invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned from practicing the invention. The objects and advantages of the invention will be obtained by means of instrumentalities in combinations particularly pointed out in the appended claims.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING
Other objects and purposes of this invention will be apparent to person acquainted with apparatus of this general type upon reading the following specification and inspecting the accompanying drawings, in which:
FIG. 1 illustrates a Fourdrinier papermaking machine incorporating the present invention therein.
FIG. 2 is an enlarged view showing a formline element with stationary and adjustable height foil blades and which forms part of the forming board section of the Fourdrinier.
FIG. 3 shows a Hydroline element with adjustable angle and height foil blades and which forms part of the hydrofoil section of the Fourdrinier.
FIG. 4 shows a Varioline element with stationary and adjustable height foil units and being part of the low-vacuum section.
FIG. 5 shows a Vaculine element with stationary and angle adjustable foil blades and being part of the low-vacuum section.
FIG. 6A shows a detailed view of an adjustable angle foil blade mounted on a C-channel and with the leading edge of the angle adjustable blade raised to +1°. FIG. 6B shows the blade of FIG. 6A having a −3° separation from an underside of the forming fabric. FIG. 6C shows a detailed view of an adjustable height foil blade mounted on a T-bar and with the leading edge of the angle adjustable blade raised to +1°. FIG. 6D shows the blade of FIG. 6C having a −3° separation from an underside of the forming fabric.
FIG. 7A shows a detailed view of an adjustable height activity blade mounted on a C-channel and with the height being at 0 mm where it is in contact with the underside of the forming fabric. FIG. 7B shows the blade of FIG. 7A at a −5 mm height below the forming fabric. FIG. 7C shows a detailed view of an adjustable height blade mounted on a T-bar and with the height being at 0 mm where it is in contact with the underside of the forming fabric. FIG. 7D shows the blade of FIG. 7C at a −5 mm height below the forming fabric.
FIG. 8A shows a control subassembly for an angle adjustable blade taken from an end of the Fourdrinier. FIG. 8B shows a cutaway view of the drive that is actuated to adjust the angle of a respective blade.
FIG. 9A shows a control subassembly for the height adjustable blade taken from an end of the Fourdrinier. FIG. 9B shows a cutaway view of the drive that is actuated to adjust the height of a respective blade.
DETAILED DESCRIPTION OF THE INVENTION
The embodiments of the invention and the various features and advantageous details thereof are more fully explained with reference to the non-limiting embodiments and examples that are described and/or illustrated in the accompanying drawings and set forth in the following description. It should be noted that the features illustrated in the drawings are not necessarily drawn to scale, and the features of one embodiment may be employed with the other embodiments as the skilled artisan recognizes, even if not explicitly stated herein. Descriptions of well-known components and techniques may be omitted to avoid obscuring the invention. The examples used herein are intended merely to facilitate an understanding of ways in which the invention may be practiced and to further enable those skilled in the art to practice the invention. Accordingly, the examples and embodiments set forth herein should not be construed as limiting the scope of the invention, which is defined by the appended claims. Moreover, it is noted that like reference numerals represent similar parts throughout the several views of the drawings.
For illustrative purposes only, the invention will be described in conjunction with a Fourdrinier papermaking machine although the invention and concept could also be applied to hybrid and gap formers, The invention is implemented in the wet section of the Fourdrinier and includes a farming board section 10 , a hydrofoil section 20 , and a low-vacuum section 30 . High-vacuum section 40 does not include automatically adjustable height blades or automatically angle adjustable blades. It should be noted that a headbox is known and is therefore not shown in FIG. 1 . Referring now to FIG. 1 , a Fourdrinier comprises a forming fabric 105 , a breast roll 106 and couch roll 107 . The forming fabric is continuous and travels between the breast and couch rolls 106 , 107 . The stock which comprises pulp fibers is deposited from the headbox to the top surface of the forming fabric 105 at a paper dryness ranging from 0.1% to 1%. Immediately following the headbox, the forming fabric passes over a forming board section 10 which comprises a formline element 11 .
As shown in FIGS. 1 and 2 , the forming board section 10 includes formline element 11 which includes a fixed ceramic lead blade 12 and a plurality of trailing blades 13 , 14 . The blades 13 , 14 are arranged beneath the forming fabric or wire and are fixed atop either stationary or adjustable C-bar or T-bar which extend from one side of the Fourdriner to the other. The support bars preferably comprise fiber reinforced composite. The stationary bars are fixed. In the preferred embodiment, the formline element 11 includes three adjustable trailing blades 13 which may be raised and lowered or the angle adjusted as shown in the respective figures with the use of respective drive 17 A. The drives are arranged at opposite ends of a support bar and fixed. The drives arranged at opposite ends of the support bar operate in concert to lower or raise a respective blade. It should be noted that the air, hydraulic and electrical lines for actuating the drives are not shown for ease in understanding the drawings. It should be understood that it is contemplated that various other drives, pistons or motors including electric and hydraulic ones and their associated supply lines may be employed to practice the invention. The adjustable blades 13 are raised or lowered to cause them to intersect the underside of the forming fabric 105 at a predetermined height to influence the alignment of the fibers within the paper web. Two fixed trailing blades 14 are arranged between the height adjustable blades 13 , as shown. In a preferred embodiment, the height of the adjustable blades may be changed to ensure that the paper fibers are aligned in a desired direction. The forming board lead blade 12 is arranged near the breast roll and is stationary. A plurality of forming board trailing blades is arranged in an alternating sequence of adjustable height blades 13 and stationary blades 14 . The forming board trailing blades preferably comprise ceramic.
During this stage, some water is drained from the stock and a very thin wet sheet is carried over to various other dewatering devices such as foil blades in hydrofoil section 20 , until a sheet paper dryness of around 1% to 1.5% is achieved. Following this, the paper dryness is increased by the foil blades in the Varioline and Vaculine in the low vacuum section 20 to a dryness level of 5%. Next, a paper dryness of 8% to 10% is achieved in the elements of the low-vacuum section 30 and the sheet is transferred to the high-vacuum section 40 to achieve a paper dryness of 18% or greater. Finally, the sheet is transferred over the couch roll where additional dryness level is achieved.
A Fourdrinier composed of the previously described equipment is fitted with a plurality of adjustable angle and height foil blades starting from the forming board section 10 and partially through the low-vacuum section 30 . As the stock travels with the forming fabric 105 , it encounters the adjustable angle and height foil blades at various points along the dewatering table to manipulate the paper web and orient more fibers in a desired direction. On the forming board section 10 and the hydrofoil or gravity section 20 , the adjustable angle foil blades generate a vacuum pulse that dewaters the stock slurry. The amount of drainage produced along each adjustable angle foil blade is determined by the angle setting of the foil blade which can be typically varied between +2 and −4 degrees. A higher angle will produce more drainage.
Also within the forming board section and hydrofoil or gravity section of the papermaking process, the stock encounters adjustable height foil blades. These blades also drain water from the stock slurry. The amount of water drained by the adjustable height foil blades is determined by their height setting in relation to the forming fabric. At a setting of −5 mm, they do not touch the fabric and do not drain any water. At a setting of 0 mm, they are in the same plane as the forming fabric and will drain water. As the adjustable height foil blades are lowered from the fabric, the amount of drainage increases up until a point at which the static and dynamic vacuum forces generated by the adjustable height foil blade are overcome by the tension forces of the forming fabric. When this occurs, the fabric breaks its seal with the adjustable height foil blade and no dewatering occurs. The setting at which this occurs will vary based on the drainage characteristics of the stock, the stock consistency, and the speed of the forming fabric. As can be understood, changing the height settings will directly influence the fiber orientation.
The wet slurry will leave the hydrofoil section 20 at a consistency of around 1.5% depending on the paper grade and speed. From here, it travels to the initial vacuum assisted foil units in the low-vacuum section 30 which are referred to as the Varioline elements. In addition to natural gravity drainage, these Varioline elements also use a dynamic and an external vacuum source to create a vacuum which is drawn onto the lower side of the forming fabric 105 . This further increases drainage within these units. The Varioline elements are equipped with a plurality of stationary and adjustable height foil blades. Similar to the previous section, as the foil blades are lowered from the forming fabric, the drainage rate increases as discussed above.
Following the Varioline table elements, another set of vacuum assisted units is encountered by the underside of the forming fabric 105 . These table elements are the Vaculine elements which are equipped with adjustable angle foil blades. Again, as the angle of the foil blades is increased, the drainage rate will increase until a consistency of 5% is achieved.
In addition to controlling drainage, the adjustable angle and height foil blades in the previously described drainage units also control turbulence within the wet slurry. This is accomplished through deflection of the forming fabric from its original plane as it travels along the top surface of the adjustable angle foil blades and adjustable height foil blades. This deflection creates a series of accelerations within the stock slurry that results in turbulence and shear within the stock slurry. This turbulence keeps the fibers fluidized and mobile within the wet slurry so that they can be orientated in the cross-machine or machine direction, depending on what the finish paper property strength requirements are.
For example, if machine direction fiber orientation is desired, the headbox jet speed is operated in a rush or drag mode to promote an initial strong machine direction alignment of the paper fibers. From here, the foil blade angles and height, along with the vacuum levels on the vacuum assisted dewatering units are adjusted to produce a high early drainage rate in the initial sheet dewatering zone (0.1% to 2% paper dryness) to immediately freeze the machine direction fiber orientation produced by the headbox.
In addition to this, the foil blade angles, heights and vacuum levels are adjusted to produce a high amount of turbulence in this paper dryness zone (01% to 2%). This keeps the fibers from entangling with each other and allows the headbox shear to become more effective in orientating fibers in the machine direction. After 2% paper dryness, the angle and height and vacuum levels are adjusted to gradually achieve a paper dryness of 5%. However, the foil angle and height are adjusted to achieve only moderate turbulence levels to prevent disruption of the machine direction fiber orientation achieved earlier in the sheet dewatering and forming process.
For cross-machine direction fiber alignment, the process is completely reversed. The headbox stock jet is adjusted to produce a speed difference close to zero (square mode) to promote the highest possible cross-machine direction fiber orientation. However, due to friction created within the headbox nozzle, a certain unavoidable degree of machine direction fiber alignment is still always present in the fiber slurry when it lands on the dewatering fabric that cannot be reversed through normal fourdrinier dewatering equipment.
To break this natural machine direction fiber orientation up and produce the most random fiber orientation and highest amount of cross-machine direction fiber orientation, the claimed invention is operated as follows. First, the foil blade angles and heights along with the vacuum levels of the vacuum assisted dewatering elements are adjusted to significantly retard drainage in the early sheet forming zone (0.1% to 2% dryness). This is completely opposite of the previously described process. In addition to this, the angle height of the foil blades are adjusted to produce a very high degree of turbulence to prevent fiber entanglement and generate the most random fiber orientation possible for the highest level of cross-machine direction fiber alignment. After a dryness of 2% is achieved, the foil angle and height is adjusted to maintain this high level of turbulence all the way until a paper dryness of 5% is achieved. A very gentle early drainage along with high turbulence all the way until a dryness of 5% is achieved will create the most random fiber network resulting in the highest amount of cross-machine direction fiber alignment.
After passing through the forming board section, the paper stock is moved along to pass through a hydrofoil or gravity section 20 equipped with Hydroline elements 21 . Each Hydroline element 21 comprises height adjustable blades 13 and angle adjustable blades 22 which are alternately arranged as shown in FIG. 3 . Depending on the paper grade, Hydrolines may also be fixed with all height or angle adjustable blades. The angle adjustable blades are controlled through an angle adjustment mechanism 25 , 27 as shown in FIG. 8A . Height adjustable blades are controlled through a height adjustment mechanism 18 , 21 as shown in FIG. 9B .
FIG. 4 depicts a vacuum assisted unit or Varioline table element 51 with stationary or angle adjustable foil blades and adjustable height blades and being part of the low-vacuum section. The Varioline element 51 comprises a dewatering blade 32 followed by height adjustable blades 13 . A deckle is arranged blades and may comprise a poly material. A drop leg 34 extends down from the Varioline for draining purposes.
FIG. 5 shows a Vaculine element 41 that is part of the low-vacuum section 30 . Vaculine elements 41 are arranged downstream from the last Varioline element 51 . Each Vaculine element includes a fixed blade 14 arranged on stationary T-bar 55 at the front and back ends as shown. Adjustable angle blades 22 are arranged in the Vaculine element. Adjustable deckles are interposed between the fixed blades 14 and the adjustable angle blades 22 as shown. A drop leg 34 extends downward for draining purposes.
FIGS. 6A , 6 B show a detailed view of an adjustable angle blade mounted on a C-channel. Blade 22 comprises a ceramic top 22 A having a yoke 22 B formed of fiberglass reinforced composite and having an offset front side as shown. The yoke 22 B is fitted atop an adjusting mechanism 25 . An underside of the angle adjusting mechanism 25 is secured within C-channel 76 via clamping bar 77 . Protective shield 79 is provided on the blade 22 to prevent items from being caught when the adjustment mechanism 25 is actuated. The C-channel is preferably formed from stainless steel and rests atop the frame of the Fourdrinier.
FIGS. 6C , 6 D show a detailed view of an adjustable angle blade mounted on a T-bar. In this instance, the mounting means is a T-bar 55 instead of the C-channel and clamping bar of FIGS. 6A , 6 B. The adjustment mechanism and remaining parts are the same and operate in similar fashion. The respective angles and their range are also the same.
FIGS. 7A , 7 B show a detailed view of an adjustable height blade mounted on a C-channel. Height adjustable blade 13 includes an upper end having a leading and trailing edge of ceramic 13 A which is fixed in a yoke 13 B preferably formed of fiberglass reinforced composite. A height adjustment mechanism 18 is arranged within the yoke 138 . An underside of the height adjusting mechanism 18 is secured within C-channel 76 via clamping bar 77 . Protective shield 79 is provided on the blade 13 to prevent items from being caught when the height adjustment mechanism 18 is actuated. The C-channel is preferably formed from stainless steel and rests atop the frame of the Fourdrinier. The height adjustment mechanism 18 includes an adjustable T-bar 21 which extends across the Fourdrinier frame and onto which the blade 13 is attached as shown FIG. 9A . In this manner, the drive 17 A raises and lowers the T-bar 21 to adjust the height of the blade 13 in relation to an underside of the forming fabric 105 .
FIGS. 7C , 7 D shows a detailed view of an adjustable height foil blade mounted on a T-bar. In this instance, the mounting means is a T-bar instead of the C-channel and clamping bar of FIGS. 7A , 7 B. The adjustment mechanism is the same and operates in similar fashion. The respective heights and their range are also the same.
FIGS. 8A , 88 shows an angle adjustment mechanism 25 which is a control subassembly for an angle adjustable blade 22 . A rotating T-bar 27 is formed from fiber reinforced composite and is the same length as a substructure upon which it is mounted. The angle adjustment mechanism 25 is secured atop a C-channel. The drive 17 B is indexed to rotate blade 22 over the range of angles shown in FIGS. 6A-D . The blade 22 is attached to the top side of T-bar 27 which is arranged to rotate in a clockwise or counter clockwise direction. In this manner, the angle of the blade 22 relative to the underside of the forming fabric is controlled.
FIGS. 9A , 9 B shows a height adjustment mechanism 78 which is a control subassembly for the height adjustable blade 13 . Blade 13 rests atop a T-bar having a drive 17 A that automatically raises and lowers the blade 13 to a desired height.
Tables 1 and 2 show blade angle and height settings for a paper grade with machine direction fiber alignment and a grade with cross-machine direction fiber alignment. The tables show a variety of angle adjustable and height adjustable blades which may be utilized in the respective regions of the wet end of the Fourdrinier to achieve synergistic results. It should be noted that in this instance seven blades are shown in each section with the abbreviations “H” or “A” indicating that the blade is either height or angle adjustable respectively. Moreover, the gravity units 1-3 correspond to the hydrofoil sections and are three Hydroline elements. Low vacuum units 1-3 correspond to Varioline elements. Low vacuum units 4, 5 correspond to Vaculine elements.
TABLE 1
Machine Direction Fiber Alignment
Low
Low
Low
Low
Low
Forming
Gravity
Gravity
Gravity
Vacuum
Vacuum
Vacuum
Vacuum
Vacuum
Blade
Board
Unit 1
Unit 2
Unit 3
Unit 1
Unit 2
Unit 3
Unit 4
Unit 5
1
H
−0.25
A
−1.5°
H
−0.5
A
−1.5°
H
−0.5
H
−0.5
H
−0.5
A
−0.75°
A
−0.0°
mm
mm
mm
mm
mm
2
A
−0.25°
H
−0.5
A
−1.5°
H
−0.5
H
−0.5
H
−0.5
H
−0.5
A
−0.75°
A
−0.0°
mm
mm
mm
mm
mm
3
H
−0.25
A
−1.5°
H
−0.5
A
−1.5°
H
−0.5
H
−0.5
H
−0.5
A
−0.75°
A
−0.0°
mm
mm
mm
mm
mm
4
A
−0.25°
H
−0.5
A
−1.5°
H
−0.5
H
−0.5
H
−0.5
H
−0.5
A
−0.75°
A
−0.0°
mm
mm
mm
mm
mm
5
H
−0.25
A
−1.5°
H
−0.5
A
−1.5°
H
−0.5
H
−0.5
H
−0.5
A
−0.75°
A
−0.0°
mm
mm
mm
mm
mm
6
A
−0.25°
H
−0.5
A
−1.5°
H
−0.5
H
−0.5
H
−0.5
H
−0.5
A
−0.75°
A
−0.0°
mm
mm
mm
mm
mm
7
H
−0.25
A
−1.5°
H
−0.5
A
−1.5°
H
−0.5
H
−0.5
H
−0.5
A
−0.75°
A
−0.0°
mm
mm
mm
mm
mm
TABLE 2
Cross-machine Direction Fiber Alignment
Low
Low
Low
Low
Low
Forming
Gravity
Gravity
Gravity
Vacuum
Vacuum
Vacuum
Vacuum
Vacuum
Blade
Board
Unit 1
Unit 2
Unit 3
Unit 1
Unit 2
Unit 3
Unit 4
Unit 5
1
H
−0.0
A
−0.0°
H
−0.0
A
−0.5°
H
−1.0
H
−1.25
H
−1.5
A
−1.5°
A
−2.0°
mm
mm
mm
mm
mm
2
A
−0.0°
H
−0.0
A
−0.25°
H
−0.0
H
−1.0
H
−1.25
H
−1.5
A
−1.5°
A
−2.0°
mm
mm
mm
mm
mm
3
H
−0.0
A
−0.0°
H
−0.0
A
−0.5°
H
−1.0
H
−1.25
H
−1.5
A
−1.5°
A
−2.0°
mm
mm
mm
mm
mm
4
A
−0.0°
H
−0.0
A
−0.25°
H
−0.0
H
−1.0
H
−1.25
H
−1.5
A
−1.5°
A
−2.0°
mm
mm
mm
mm
mm
5
H
−0.0
A
−0.0°
H
−0.0
A
−0.5°
H
−1.0
H
−1.25
H
−1.5
A
−1.5°
A
−2.0°
mm
mm
mm
mm
mm
6
A
−0.0°
H
−0.0
A
−0.25°
H
−0.0
H
−1.0
H
−1.25
H
−1.5
A
−1.5°
A
−2.0°
mm
mm
mm
mm
mm
7
H
−0.0
A
−0.0°
H
−0.0
A
−0.5°
H
−1.0
H
−1.25
H
−1.5
A
−1.5°
A
−2.0°
mm
mm
mm
mm
mm
It is to be understood that the invention is not limited to the exact construction illustrated and described above, but that various changes and modifications may be made without departing from the spirit and the scope of the invention as defined in the following claims. While the invention has been described with respect to preferred embodiments, it is intended that all matter contained in the above description or shown in the accompanying drawings shall be interpreted as illustrative and not in limiting sense. From the above disclosure of the general principles of the present invention and the preceding detailed description, those skilled in the art will readily comprehend the various modifications to which the present invention is susceptible. Therefore, the scope of the invention should be limited only by the following claims and equivalents thereof. | An improved method for producing paper from pulp includes a plurality of subassemblies arranged in the forming or wet section of a Fourdrinier. The Fourdrinier includes a dewatering table having a plurality of blades that are static and on-the run adjustable in height and/or angle to control orientation of paper fibers in the stack to create a superior quality of paper and improved paper strength characteristics. Gravity and vacuum assisted drainage elements are equipped with on-the-run adjustable angle and height dewatering foil blades starting from a paper dryness of 0.1% and extending all the way to 5% dryness. The result of this process and machine is to improve the paper quality, save fibers and chemicals and fulfill the required paper properties. | 3 |
[0001] This is a complete application claiming benefit of provisional application Ser. No. 60/473,467 filed May 28, 2003.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates generally to protective bumper systems, and relates more particularly to strip assemblies for protecting surfaces such as walls, display cases, furniture, and the like, from damage caused by inadvertent impact.
[0004] 2. Discussion of the Prior Art
[0005] Wall surfaces in hallways, particularly in heavily trafficked areas such as hospital corridors, airport walkways and the like, are commonly exposed to impact damage resulting from misguided carts, gurneys, people movers and the like. Likewise, grocery island cases, freezer chests, merchandise display cases, and other such items found in supermarkets, pharmacies, and department and specialty stores are often damaged in a similar manner.
[0006] To minimize such damage, bumper guards or strip assemblies of various designs have been proposed for surface mounting as chair rails, or to otherwise absorb impacts on flat walls or about corners of such structures. Protective devices of this nature must not only be functionally effective to absorb repeated impacts from different directions, but they must be simple and inexpensive to manufacture and utilize, and aesthetically pleasing, as well.
[0007] Bumper guards and the like commercially available heretofore tend to compromise one or more of the foregoing criteria. For example, in order to improve impact resistance, some products are unduly complex, making them relatively expensive to manufacture. To minimize manufacturing costs, other products may not provide adequate protection to the surfaces on which they are mounted, or may tend to deteriorate quickly in use. Finally, some such strip assemblies fail to hide the mounting hardware or otherwise present an unsightly appearance which is commercially undesirable.
SUMMARY OF THE INVENTION
[0008] It is a primary object of this invention to provide several embodiments of bumper assemblies, each of which include a base member to be attached to a surface to be protected with a top or bumper which is easily and securely affixed to the base without the need for tools to reduce installation time while providing a functionally effective, active locking, assembly where the bumper element will not be easily disengaged from the base regardless of the angle of impact against the arched surface of the bumper.
[0009] Another object of this invention is to provide an impact deflection system which includes mechanical and frictional anti-slip and anti-shrink properties to preclude or significantly reduce inadvertent lateral movement between the bumper and the base in use even after repeated impacts.
[0010] A further object of this invention is the provision of a protective strip assembly with a vinyl top or bumper element which, in some embodiments, is “rigid”, providing high impact strength in an inexpensive manner and, in other embodiments, is “flexible”, providing superior radius capability while maintaining its geometry to insure maximum protection where it is needed most. Extended lengths of such bumpers can be flexed to permit access to the underside so that the screws or the like securing the base to the surface to be protected can be hidden in the final assembly.
[0011] Still another object of this invention is to provide a bumper construction which, in addition, to the interengageable locking base and bumper elements, is designed to interact with a full range of injection molded flexible vinyl caps and corners to enable the bumper assembly to be used in a straight run or continuously around corners of a square or rectangular unit, or even a hexagonal, or other shaped unit.
[0012] Yet another object of this invention is the provision of a bumper construction of the type described wherein the bumper elements can be extruded from relatively rigid plastics materials or co-extruded from relatively rigid and relatively flexible plastics materials and the bases can be pre-slotted and extruded aluminum or plastics materials for straight runs or radius application, producing an assembly of parts which is simple and inexpensive to manufacture, install and use, offers high shatter resistance with a professional finish in a variety of colors to produce a highly attractive appearance in the final product.
[0013] It is to be understood that the instant inventive concepts are not limited by size or materials although, to facilitate a better understanding of the invention, illustrative embodiments of 1″ and 2″ bumper construction elements are illustrated and preferred materials for each of the elements are disclosed.
[0014] Upon further study of the specification, additional objects and advantages of this invention will become apparent to those skilled in the art.
BRIEF DESCRIPTION OF THE DRAWINGS
[0015] These and other objects, features and many of the attendant advantages of this invention will be better understood by those with ordinary skill in the art in connection with the following detailed description of the preferred embodiments and the accompanying drawings wherein:
[0016] FIG. 1 is a fragmentary perspective view of a 1″ base element according to the instant inventive concepts;
[0017] FIG. 1A is an end elevational view of the base element of FIG. 1 with a frictional coating such as thermoplastic polyurethane (TPU) schematically shown on the bulbous projections to minimize movement of the bumper relative to the base even after repeated impact from different directions;
[0018] FIG. 2 is a fragmentary perspective view of a 1″ top or bumper element formed of relatively “rigid” plastics material such as polyvinyl chloride (PVC);
[0019] FIG. 3 is an end view of the assembly of the bumper element of FIG. 2 with the base element of FIG. 1 ;
[0020] FIG. 4 is an end elevational view of a 1″ bumper element including a relatively “flexible” PVC or the like arch co-extruded with a relatively “rigid” PVC or the like bridge according to the instant inventive concepts;
[0021] FIG. 5 is an end elevational view of the assembly of the bumper element of FIG. 4 with the base element of FIG. 1 ;
[0022] FIG. 6 is an end elevational view of a 2″ base element according to the instant inventive concepts;
[0023] FIG. 6A is a view similar to FIG. 1A showing the bulbous projections of the base element of FIG. 6 coated with a frictional material;
[0024] FIG. 7 is an end elevational view of a 2″ “rigid” bumper element;
[0025] FIG. 8 is an end elevational view of the assembly of the bumper element of FIG. 7 with the base element of FIG. 6 ;
[0026] FIG. 9 is a cross-sectional view through a 2″ co-extruded “flexible” bumper element according to this invention;
[0027] FIG. 10 is a cross-sectional view through the assembly of the bumper element of FIG. 9 with the base element of FIG. 6 ;
[0028] FIG. 11 is a cross-sectional view through the bumper assembly of FIG. 10 attached to a wall or fixture, the surface of which is to be protected;
[0029] FIG. 12 is an end elevational view of a 1″ “quick stop” cap for use with a bumper assembly according to this invention;
[0030] FIG. 13 is a cross-sectional view thereof taken along lines A-A of FIG. 12 ;
[0031] FIG. 14 is a top plan view of the stop cap of FIG. 12 ;
[0032] FIG. 15 is an end elevational view showing the stop cap of FIGS. 12-14 engaged with a bumper assembly as shown in FIG. 3 ;
[0033] FIGS. 16-19 are views of a 2″ “quick stop” cap similar to the views of the 1″ quick stop cap illustrated in FIGS. 12-15 ;
[0034] FIG. 20 is an end elevational view of a 1″ “snap-on” cap for % use with a bumper assembly according to this invention;
[0035] FIG. 21 is a cross-sectional view thereof taken along lines A-A of FIG. 20 ;
[0036] FIG. 22 is an enlarged detail of the female connector of the bumper element shown within the dotted circle in FIG. 20 ;
[0037] FIG. 23 is a top plan view of the 1″ snap-on cap of FIG. 20 ;
[0038] FIG. 24 is an end elevational view showing the snap-on cap of FIGS. 20-23 engaged with a bumper assembly such as shown in FIG. 3 ;
[0039] FIGS. 25-29 are views of a 2″ snap-on cap similar to the views of the 1″ snap-on cap illustrated in FIGS. 20-24 ;
[0040] FIG. 30 is an end elevational view of a 1″ “snap-on 90°” cap for use with a bumper assembly according to this invention;
[0041] FIG. 31 is a cross-sectional view thereof taken along lines A-A of FIG. 30 ;
[0042] FIG. 32 is an enlarged detail view of the female connector of the bumper element shown within the dotted circle in FIG. 30 ;
[0043] FIG. 33 is an end elevational view of one end of the snap-on 90° cap of FIG. 30 engaged with a bumper assembly such as shown in FIG. 3 ;
[0044] FIGS. 34-37 are views of a 2″ snap-on 90° cap similar to the views of the 1″, snap-on 90° cap shown in FIGS. 30-33 ;
[0045] FIG. 38 is an end elevational view of an illustrative 1″ “snap-on” cap of a different angle according to this invention;
[0046] FIG. 39 is a cross-sectional view thereof taken along lines A-A of FIG. 38 ;
[0047] FIG. 40 is an enlarged detail of the female connector of the bumper element shown within the dotted circle in FIG. 38 ;
[0048] FIG. 41 is an end elevational view of one end of the snap-on cap of FIG. 38 engaged with a bumper assembly such as shown in FIG. 3 ; and
[0049] FIGS. 42-45 are views of a 2″, snap-on cap similar to the views of the 1″ snap-on cap illustrated in FIGS. 38-41 .
[0050] Like reference characters refer to like parts throughout the several views of the drawings.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0051] The foregoing descriptions and drawings should be considered as illustrative only of the principles of the invention. Numerous applications of the present invention will readily occur to those skilled in the art. Therefore, it is not desired to limit the invention to the preferred embodiments or the exact construction and operation of the preferred embodiments shown and described. Rather, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
[0052] Referring now to the drawings, and more particularly to FIG. 1 , a preferred form of base element according to the instant inventive concepts is designated generally by the reference numeral 50 and, although only a short portion is illustratively seen in FIG. 1 , the element 50 can be of indeterminate length depending upon its application. The base element 50 is preferably extruded, either from a “rigid” plastics material such as PVC or from aluminum, although other materials may be substituted therefor without departing from the instant inventive concepts. The term “rigid” PVC is well understood by those with ordinary skill in this art.
[0053] The base element 50 comprises a floor portion 52 , and a pair of longitudinally extending, transversely spaced, male connectors 54 , each comprising a stem portion 56 and a bulbous head 58 . Although not shown, the floor 52 can be pre-slotted or scored for passage or location of screws or the like adapted to attach the base element 50 to a wall or a fixture to be protected.
[0054] With reference now to FIG. 1A , the upper surfaces of the bulbous heads 58 of the male elements 54 may be coated with a friction-producing material 59 such as thermoplastic polyurethane (TPU) for a purpose to be described further hereinafter. If the base element 50 is formed of a plastics material such as PVC, the TPU may be co-extruded with the PVC in a well known manner.
[0055] With reference now to FIGS. 2 and 3 , one form of a top or bumper element according to this invention is shown at 70 as comprising an extruded arch 71 preferably formed of a “rigid” PVC. The lower inner longitudinal edges of the bumper element 70 are angled as seen at 72 and a pair of inwardly extending arcuate female connectors 74 , whose internal surfaces are complementary to the bulbous heads 58 of the male elements 54 on the base element 50 , are integrally extruded with the arch 71 .
[0056] In use, the base element 50 is screwed or otherwise attached as by screws 60 to a supporting surface schematically seen at 65 , and the female connectors 74 of the top or bumper element 70 are simply pressed into place on the bulbous heads 58 of the male connectors 54 to form the assembly 75 seen in FIG. 3 . Thus, once the base element and the caps or corners to be discussed below are secured to the supporting surface, no tools are necessary to complete the assembly. Moreover, the unique complementary nature of the arcuate female connectors 74 provides both inner and outer engagement with the bulbous heads 58 of the male connectors 54 to resist disengagement or damage to the bumper assembly 75 from repeated impacts, regardless of the angle of impact. Moreover, the frictional TPU coating 59 enhances the engagement of the base element 50 and the bumper element 70 to preclude “shrinkage”, that is, compression of the bumper element 70 which can result from repeated impacts causing the bumper element 70 to slide along the base element 50 causing separation at the ends of the bumper assembly 75 . If desired, the upper surfaces of the male connectors 54 or the inner surfaces of the female connectors 74 or both can be grooved or ribbed to enhance the mechanical engagement between these elements.
[0057] The manner in which the angled surfaces 72 of the bumper element 70 extend down along the outside edges 52 ′ of the base element 52 , and the hidden screws 60 attaching the base element 50 to the supporting surface 65 , allows the aesthetic value to be maintained well after installation.
[0058] Referring now to FIGS. 4 and 5 , a “flexible” 1″ bumper element 80 is shown as a co-extrusion of a more resilient plastics material such as PVC forming the arch 81 with an internal, co-extruded, more rigid, PVC bridge 82 defining the female connectors 84 for attachment to the base element 50 to form the assembly 85 as seen in FIG. 5 . In this manner, while the connection between the base element 50 and the bumper element 80 is between relatively rigid plastics materials, the more resilient material of the arch 81 provides a superior radius capability which maintains its geometry to ensure maximum protection where it is needed most. Once again, however, particularly with a coating 59 of TPU or the like on the bulbous heads 58 of the base element 50 , the assembly 85 seen in FIG. 5 resists “shrinkage” and slippage between the elements even with repeated impacts from different directions.
[0059] With reference to FIGS. 6, 6A and 7 - 10 , parts of a 2″ bumper assembly similar to the bumper assembly of FIGS. 1, 1A and 2 - 5 , are identified by the same reference characters followed by the suffix “a”. For all intents and purposes, other than the size and curvature of the parts, the elements are substantially identical with the exception that, in the rigid bumper element 70 a of FIGS. 7 and 8 , a bridge 76 a interconnects the female connectors 74 a to the arch 71 a.
[0060] For illustrative purposes, the flexible 2″ bumper element 80 a in FIGS. 8 and 9 has been cross-hatched for two different types of plastics material and the base element 50 a has been cross-hatched for metal, e.g., aluminum. However, it is to be understood that the materials of the various elements can be varied within the skill of the art. Additionally, the drawings are not to be considered to scale and, as noted above, the 1″ and 2″ bumper assemblies have been shown merely as illustrative of the variations in size and construction of the elements of the impact deflection system of this invention. FIG. 11 illustrates the manner in which a bumper assembly, in this instance, the 2″ flexible bumper assembly 85 a of FIG. 10 , is attached to a vertical supporting surface 65 .
[0061] Referring now to FIGS. 12-15 , a 1″ injection molded “quick stop” cap is designated generally by the reference numeral 90 and comprises an end or facing element 92 and a perpendicularly extending tab element 94 . Depressions 96 are formed in the rear surface 92 ′ of the end element 92 for reception of the ends of the male connectors 54 on a base element such as the element 50 of FIG. 1 . An opening 98 can be formed through the tab element 94 for reception of a screw of the like (not shown) to attach the same to a supporting surface through the floor 52 of the base element 50 .
[0062] The quick stop cap 90 may be used to cover the end or ends of a bumper assembly, particularly adjacent a flat surface such as an intersecting wall or a door frame (not shown). Following the attachment of a base element such as 50 to the supporting surface, a first quick stop cap such as 90 may be affixed at one end by drilling or otherwise attaching a screw (not shown) through the opening 98 and the floor 52 of the base element 50 to secure the stop cap 90 directly to the supporting surface. It is to be noted that the tab 94 is spaced slightly upwardly from the lower end 92 ″ of the end element 92 to permit the floor element 52 of the base element to underly the same, and the width of the tab element 94 is such as to fit between the stems 56 of the male connectors 54 .
[0063] The other ends of the male connectors 54 of bumper can then be engaged in the depressions. 0.96 of a further quick stop cap and screwed through the tab element 94 to a supporting surface. A bumper element 70 can then be seated on the base element 50 by simple pressure on the arch 71 of the bumper element 70 .
[0064] Alternatively, at the opposite end of a run, if necessary, the bumper element can be lifted slightly so that one of the other accessories to be discussed hereinbelow can be secured to the bumper assembly and the bumper element 70 pressed into position on the base element 50 adjacent thereto.
[0065] With reference now to FIGS. 16-19 , the construction and assembly of a 2″ quick stop cap 92 a are designated by the same reference characters as the 1″ quick stop cap of FIGS. 12-15 , followed by the suffix “a”.
[0066] With reference now to FIGS. 20-24 , an injection molded 1″, “snap-on” cap is identified by the reference numeral 100 which, in part, is similar to the stop cap 90 , but includes an arcuate end portion for aesthetic purposes as illustrated at 100 . The snap-on cap 100 is similar to the stop cap 90 in having a slightly raised tab element 102 with an opening 104 therethrough affixed to an element 106 , but includes a pair of integrally molded arcuate female connectors 108 to snap over the male connectors 54 of a base element such as shown at 50 and an arcuate extension 110 to provide a more aesthetic appearance where a flat end cap is not necessary.
[0067] In FIGS. 25-29 , a 2″ snap-on cap 100 a is designated by the same reference characters as the 1″ snap-on cap 100 of FIGS. 20-24 , followed by the suffix “a”.
[0068] With reference to FIGS. 30-33 , a 1″ injection molded “snap-on 90°” cap is seen at 120 and is adapted to interconnect a pair of bumper assemblies such as shown at 75 in FIG. 3 on perpendicular sides of a square or rectangular item to be protected from impact such as a grocery island, a freezer case or a merchandise display case (not shown). The 90° cap 120 is similar to the snap-on cap 100 of FIGS. 20-24 , but includes a pair of snap-on sections 122 , 122 perpendicularly connected by a 90° arcuate connecting section 124 to enable the same to pass around a corner. Each section 122 includes a tab element 125 with an aperture 128 and a pair of arcuate female connectors 130 .
[0069] In FIGS. 34-37 , a 2′ snap-on 90° cap 120 a is designated by the same reference characters as the 1″ snap-on 90 ′ cap 100 followed by the suffix “a”.
[0070] In FIGS. 38-41 and 42 - 45 , illustrative injection molded 1″ and 2″ snap-on caps are designated by the same reference characters as the 1″ 90°, illustratively shown as 135°, snap-on cap 120 followed by the suffixes “c” and “d”, respectively, These caps are substantially identical to the 90° caps, except that the arcuate connecting sections have angles other than 90° to enable bumper assemblies to be interconnected around a hexagonal or other shaped unit to be protected, rather than a square or rectangular unit. Obviously, snap-on caps of various angular orientations can be provided for unique display cases or the like.
[0071] The use and operation, as well as the attendant advantages, of the bumper assemblies and the above-described accessories will be obvious to the skilled artisan. A base element and selected end cap or corner are first screwed or otherwise connected to the surface to be protected. One end of a bumper element is then engaged against the end cap or corner and pressed against the base element over its length. The opposite end of the bumper element may be lifted sufficiently to secure another end cap or corner and the assembly is then completed.
[0072] The foregoing descriptions and drawings should be considered as illustrative only of the principles of the invention. Numerous applications of the present invention will readily occur to those skilled in the art. Therefore, it is not desired to limit the invention to the preferred embodiments or the exact construction and operation shown and described. Rather, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention. | A protective bumper strip assembly for protecting surfaces such as walls, display cases, furniture, and the like, from damage caused by inadvertent impact. The protective bumper strip assembly comprises a base member attachable to a supporting surface to be protected and a bumper that is press-fit or snap-fit to the base member. The press-fit interconnection is formed from male and female interconnecting elements to form a mechanical connection therebetween. The male and female interconnecting elements include a high friction material to prevent slippage therebetween when the bumper is impacted. The interengagement between the base member and the bumper requires no additional interconnecting or attachment members. The base member includes a pair of elongated arcuate male members which receive arcuate complementary female interconnecting elements extending from the bumper. Free end portions of the assembly may include cap elements of flat or spherical shape to enclose the ends of the strip assemblies. | 4 |
BACKGROUND OF THE INVENTION
The invention relates to a device for manufacturing a tube coupling of two tube ends, and in particular a tube coupling which at least comprises a basic body enclosing the tube end, and a press means enclosing the basic body wherein the basic body is radially urged into the surface of the tube by axially shifting the press means.
Pipe connections using this principle are known from the patent specifications U.S. Pat. Nos. 3,827,727, 3,893,720, 4,026,006, 4,061,367, 4,482,174 and 5,110,163.
The disadvantage of these pipe connections is in that they are functionally restricted in use regarding the size of the tube diameter, claims of quality on the tube to be connected, and the amount of pressure of the medium. Moreover, the constructional design of the displacing potentials formed in these tube couplings provides in addition to the intended radial crowding being absolutely necessary to obtain a pressure sealed connection, an axial crowding which does not contribute to the pressure sealed connection but influences the forces of pressure to be applied from the outside such that the forces of pressure exceed the dimension required for the radial crowding. Thus, from the start follows an oversizing of both the press tool and single elements of the tube coupling.
SUMMARY OF THE INVENTION
The invention is based upon the object to provide a pressure sealed pipe connection by axially pressing which ensures highest universality regarding the requirements of quality of the tubes to be connected.
Another object of the invention is in that to make a sealed connection in the high pressure range as well by the use of normal commercially available tubes, e.g. welded tubes made of most different materials, and the thus permissible tolerances regarding the mechanical properties and length related dimensions.
Further, it is an object of the invention to minimize the forces required for axially pressing on the press elements, and thus the force to be applied for penetrating into the tube surface at maximum penetrating depth.
These objects will be solved by a device according to the features of the first claim.
The device for manufacturing a pressure sealed tube coupling having at least one tube end comprises a sleeve shaped, rotationally symmetrical basic body wherein the basic body at least includes one substantially cylindrical interior space provided with teeth means for receiving the tube end, and the teeth means are radially displaced into the surface of the tube end received by the interior space by means of press means acting upon the outer surface of the basic body.
The basic body comprises a hollow cylinder shaped coupling sleeve having a wall thickness substantially remaining the same wherein at least two radially surrounding indentations are located on the inside of the coupling sleeve which are spaced to one another and recessed in comparison with the inner diameter of the coupling sleeve. On the outside of the coupling sleeve are formed radially surrounding flat locating features opposite the respective indentation which have a width corresponding to the width of the indentation. For it, a pressure ring concentrically slidable over the coupling sleeve is provided to cover the coupling sleeve in almost its total length wherein the pressure ring has radially surrounding projecting parts corresponding to the locating features on its inside, and an increasing cone shaped enlargement directed from each end of the pressure ring towards its centre, on its outside.
A press ring concentrically enclosing the pressure ring is associated to the pressure ring on each side, wherein each press ring on its inside has a cone shaped enlargement corresponding to the cone shaped enlargement of the pressure ring such that a radial displacement of the indentations into the surface of the tube received by the coupling sleeve by means of the projecting parts and the locating features corresponding to the projecting parts occurs during the axial shift of the press rings against each other from a spaced initial position into an almost final position without any distance.
Further features of the invention are cited in the dependent claims.
The invention will be explained in more detail according to an embodiment shown the associated drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a longitudinal section through a tube coupling according to the invention performed on both sides wherein on the left hand of the axis of symmetry A—A a pre-pressed half, and on the right hand of the axis of symmetry A—A a pressed half of the tube coupling are illustrated;
FIG. 2 is a longitudinal section through the tube coupling according to FIG. 1 having an inserted supporting sleeve;
FIG. 3 is a longitudinal section through the upper half of the tube coupling according to FIG. 1 wherein the opposite press rings are shifted against each other by screws;
FIG. 4 is a longitudinal section through the upper half of a pressure ring having a stepped cone shaped formation of the surface;
FIG. 5 are two views of a pressure ring segmented by slots;
FIG. 6 is a longitudinal section through the upper half of another embodiment of the tube connection;
FIG. 7 is a longitudinal section through a tube coupling according to the invention in another embodiment which is performed on both sides;
FIG. 8 is a longitudinal section through a tube coupling according to FIG. 7 in which the pressure ring is divided;
FIG. 9 is a longitudinal section through the tube coupling according to the invention in another embodiment.
DETAILED DESCRIPTION
FIG. 1 shows a longitudinal section through a tube coupling 1 according to the invention performed on both sides wherein on the left hand of the axis of symmetry A—A a pre-pressed and on the right hand of the axis of symmetry A—A a pressed half of the tube coupling 1 are illustrated.
The tube coupling 1 comprises a hollow cylinder shaped coupling sleeve 2 having axially opposite entering ends 3 into which the ends of the tubes 4 to be connected are inserted. The tube coupling 1 is constructed symmetrically with respect to the axis A—A, that is the subsequently described coupling elements and acting relations always relate to one half of the coupling sleeve 2 . In the present embodiment in which two tubes 4 having the same diameter are to be connected in a pressure sealed manner the constructional formation of the coupling elements on the one half of the coupling sleeve 2 is in symmetry to the axis A—A with that of the other half of the sleeve. Therefore, in the present case the structure and action of the tube coupling 1 will be described for one side only.
The coupling sleeve 2 is generally fabricated from a material which is identical with the material of the tubes 4 .
The coupling sleeve 2 is a hollow cylinder the wall thickness of which substantially remains constant over the length of the coupling sleeve 2 , and which is in relation to the outer diameter of the tube 4 and the wall thickness thereof.
The inside of the coupling sleeve 2 comprises radially surrounding indentations wherein one indentation 6 is located spaced in the proximity of the entering end 3 of the coupling sleeve 2 , and the second indentation 7 is located spaced to the first indentation 6 towards the axis A—A. In the present embodiment, the indentation 6 , 7 comprises three juxtaposed teeth which are recessed in comparison with the inner diameter of the coupling sleeve 2 in the way such that the diameter measured in the area of the tooth tips equals the inner diameter or is greater than the inner diameter of the coupling sleeve 2 . As a result, it is avoided that the tooth tips are damaged with inserting the tube 4 into the interior space of the coupling sleeve 2 .
The tooth tips of the indentations 6 , 7 are allowed to be differently formed according to the case of application. Thus, it is conceivable to flatten or round the tooth tip in order to thus influence the penetrating behavior of the indentation 6 , 7 into the surface of the tube 4 . On the outside of the coupling sleeve 2 there are located locating features which represent as radially surrounding, flat grooves 8 , 9 opposite the respective indentations 6 , 7 . The function of these grooves 8 , 9 will be dealt with in a later connection.
In a particular case of application, in the area of the axis of symmetry A—A, thus in the area wherein in the coupling position the ends of the tubes 4 are oppositely located the coupling sleeve 2 can be realized with an inner stepped neck portion which causes limiting the inserting depth of the inserted tube 4 . When the coupling sleeve 2 is not necked inside as in the present embodiment, thus it can be used as a shifting sleeve.
On the coupling sleeve 2 is located a pressing set 10 coaxially located therewith which comprises a pressure ring 11 , two press rings 12 , 13 and a covering sleeve 14 as the case may be.
The pressure ring 11 is a rotationally symmetrical hollow cylinder which on the inside comprises locating features for fixing on the coupling sleeve 2 . These locating features represent radially surrounding projecting parts 15 , 16 which are realized such that they correspond to the grooves 8 , 9 on the outside of the coupling sleeve 2 . The axial position of the pressure ring 11 on the coupling sleeve 2 will be defined by the respective combination of the groove 8 , 9 /projecting part 15 , 16 . The diameters of the groove basic, on the one hand, and of the projecting part, on the other hand, will be selected such that between the two structural members a pre-pressed condition realized by means of a clearance fit is obtained which facilitates an assembly of the tube coupling 1 .
On the top surface of the pressure ring 11 are located cone shaped enlargements 17 , 18 originating from the ends of the pressure ring 11 which increase evenly and continuously up to the axis of symmetry B—B.
Each cone shaped enlargement 17 , 18 of the pressure ring 11 is associated to a press ring 12 , 13 . The press rings 12 , 13 represent rotationally symmetrical hollow cylinders which on their inside comprise a cone shaped enlargement 19 , 20 directed towards the axis of symmetry B—B. This cone shaped enlargement 19 , 20 of the press ring 12 , 13 corresponds to the associated cone shaped enlargement 17 , 18 of the pressure ring 11 by contacting the two structural members on the cone shaped surfaces.
In the pre-pressed condition of the tube coupling 1 the press rings 12 , 13 are pushed on the respective enlargement 17 , 18 of the pressure ring 11 so far that there is a sufficient distance between the press rings 12 , 13 opposing each other which is measured, such that during carrying out the pressing action an axial motion of the press rings 12 , 13 will be permitted to each other.
The top surface of each press ring 12 , 13 comprises a pair of radially surrounding spaced grooves 21 , 22 which receive a covering sleeve 14 acting as retaining element. The covering sleeve 14 comprises on its borders inwardly facing edges 24 , 25 which will be engaged with the circumferential grooves 21 , 22 . On that occasion, in the pre-pressed condition of the tube coupling 1 , the edges 24 , 25 are engaged with the groove 21 nearest the axis of symmetry B—B, respectively, wherein in the pressed condition of the tube coupling 1 , the engagement of the edges 24 , 25 merges to the adjacent grooves 22 . To facilitate this transition during the axial motion of the press rings 12 , 13 to each other both the edges 24 , 25 and the grooves 21 , 22 comprise run-out bevels.
The covering sleeve 14 with the pre-pressed tube coupling 1 accomplishes the function to keep the individual elements of the press set 10 together in a condition in which they are capable of being assembled.
With the pressed tube connection 1 the object of the covering sleeve 14 is in that to actively oppose an unintentionally loosening of both press rings 12 , 13 , and moreover to avoid soiling of the space 26 located between the press rings 12 , 13 .
In the following, the action of producing the pressure sealed tube coupling 1 will be described. A press set 10 including a pressure ring 11 a pair of press rings 12 , 13 and the covering sleeve 14 is pushed on the coupling sleeve 2 . On that occasion, the inwardly facing projecting parts 15 , 16 of the pressure ring 11 lock into the respective groove 21 , 22 located on the outside of the coupling sleeve 2 thus defining the place of the pressing set 10 on the coupling sleeve 2 . This assembly is allowed to be prefabricated and delivered to the assembly yard depending on the nominal width of the tubes 4 to be connected. On the assembly yard, the ends of the tubes 4 to be connected are inserted with a predetermined length into the coupling sleeve 2 . By means of suitable tools which are known per se and thus are not described, the press rings 12 , 13 associated to a pair are axially shifted against each other. Then, the press rings 12 , 13 slide over the cone shaped surfaces between the press ring 12 , 13 and the pressure ring 11 and displace the material of the pressure ring 11 in the radial direction. The displacement primarily occurs through the projecting parts 15 , 16 of the pressure ring 11 and is transferred to the indentations 6 , 7 opposite the grooves 8 , 9 . The indentations 6 , 7 are radially urged into the surface of the inserted tubes 4 and ensure in this way a pressure sealed connection between the coupling sleeve 2 and the tube 4 .
Both, the axial force to be applied and the penetrating depth and supporting force as well of the circumferential indentation 6 , 7 of the coupling sleeve 2 in the tube 4 to be connected can be influenced through the angle of the cone shaped enlargements of the press rings 12 , 13 and the pressure ring 11 , and the path as well travelled during axially pushing together.
In FIG. 2 is shown the same tube coupling 1 as described in FIG. 1 . The difference is in that a supporting sleeve 27 will be inserted into the tube 4 , which in the area of the displacement provides for the tube 4 a resistance supporting the penetration of indentation 6 , 7 into the surface of the tube 4 . The supporting sleeve 27 comprises radially surrounding asperities on its outer surface which balance the tolerances of the tube 4 during inserting it into the supporting sleeve 27 .
In FIG. 3 applying the axial shifting force upon the press rings 12 , 13 by means of screws is shown. The press rings 12 , 13 comprise bores axially located on a graduated circle 32 wherein the bore located within the press ring 12 is formed as a through hole 28 , and the bore axially opposite inside the press ring 13 is formed as a threaded hole 29 . Due to uniformly pulling the screws 23 the press rings 12 , 13 are displaced against each other on the cone shaped surfaces.
As shown in FIG. 4 the top surface of the pressure ring 11 can be realized in a stepped way up to the axis of symmetry B—B wherein a conically increasing, plane formed section 30 is followed by an undercut section 31 which is formed as a cone shaped neck. This sequence repeats preferably four times up to the axis of symmetry B—B. These undercut sections 31 prevent mutually sliding in the pre-pressed and finish-pressed condition, respectively, with a complementary formation of the inside of the press rings 12 , 13 .
In FIG. 5 the pressure ring 11 is shown in a partly segmented formation. The body of the pressure ring 11 is slotted except from the radially surrounding projecting parts 15 and 16 . As a result, the required axial forces of pressure are minimized with steady properties of the pressing set 10 and the radial displacement. The number and the width of the slots 34 are in a direct combination with the radial shortening of the pressure ring 11 .
In a modified form the pressure ring 11 can also be composed of single arcuate segments.
The form of the fixing area between the pressure ring 11 and the coupling sleeve 2 shown in FIG. 6 is allowed to be further modified. Thus, for example it is possible for the fixing area on the coupling sleeve 2 to be carried out in circumferential way. The circumferential ring grooves 33 serve as a balancing area for stresses in the structural members of the coupling becoming too strong which occur with pressing the tubes having a great range of tolerance when the tolerance of the outer tube diameter is in the upper limit range.
The forms of the bottom side of the pressure ring 11 shown in the embodiments are allowed to be further modified without thus being departed from the scope of protection of the patent.
The tube coupling will be described in another embodiment. The tube coupling 101 according to FIG. 7 comprises a hollow cylinder shaped coupling sleeve 102 having axially opposite entering ends 103 into which the ends of the tubes 104 to be connected are pushed in up to the axis of symmetry C—C.
The inside of the coupling sleeve 102 comprises radially surrounding indentations wherein one indentation 106 is located spaced in the proximity of the entering end 103 of the coupling sleeve 102 , and the second indentation 107 is located spaced towards the first indentation 106 in the direction of the axis C—C in the proximity of the tube end pushed in. Therefore, the ends of the tubes 104 will be positioned in the coupling sleeve 102 such that each tube end is associated to both an indentation 106 and indentation 107 .
On the coupling sleeve 102 is located a press set 110 coaxially mounted thereto which comprises the pressure ring 111 , and two press rings 112 , 113 .
The pressure ring 111 is a rotationally symmetrical, hollow cylinder being substantially of the same length with the coupling sleeve 102 . The pressure ring 111 and the coupling sleeve 102 comprise on their ends axially effecting locating features which represent on the coupling sleeve 102 as a flat circumferential swelling 121 and on the pressure ring 111 as a flat groove 122 corresponding to the swelling 121 . These locating features define the axial position of the pressure ring 111 on the coupling sleeve 102 , and ensure in the pre-pressed condition an interlocking connection between the coupling sleeve, on the one hand, and the pressure ring, on the other hand. A high degree of prefabrication of the tube coupling is obtained by means of this cohesion of the single elements of the assembly.
On the top surface of the pressure ring 111 are located cone shaped enlargements 117 , 118 originating from the ends of the pressure ring 111 which increase continuously and evenly up to the axis of symmetry C—C. A press ring 112 , 113 is associated to each cone shaped enlargement 117 , 118 of the pressing ring 111 . The press rings 112 , 113 represent as rotationally symmetrical hollow cylinders which comprise a cone shaped enlargement 119 , 120 directed towards the axis of symmetry C—C on its inside. These cone shaped enlargements 119 , 120 of the press rings 112 , 113 correspond to the associated cone shaped enlargements 117 , 118 of the press rings 111 by contacting the two structural members each other on the cone shaped surfaces.
In the pre-pressed condition of the tube coupling 101 the press rings 112 , 113 are pushed on the respective enlargement 117 , 118 of the pressure ring 111 so far that between the opposite press rings 112 , 113 a sufficient distance exists which is dimensioned such that an axial motion of the press rings 112 , 113 to each other will be permitted during carrying out the pressing action.
The process of fabrication of the pressure sealed tube coupling 101 will be described below. A press set comprising the pressure ring 111 and a pair of press rings 112 , 113 is pushed on the coupling sleeve 102 . According to the nominal width of the tubes 104 to be connected this assembly can be prefabricated and delivered to the assembly yard. On the assembly yard the ends of the tubes 104 to be connected are inserted with a predetermined length into the coupling sleeve 102 up to the axis of symmetry C—C. By means of suitable tools which are known per se and thus are not described the press rings 112 , 113 associated to one pair are axially displaced against each other. On that occasion, the press rings 112 , 113 slide over the cone shaped surfaces between the press ring 112 , 113 and the pressure ring 111 , and displace the material of the pressure ring 111 in the radial direction. The displacement primarily occurs through the projecting parts 115 , 116 of the pressure ring 111 , and will be transferred to the indentations 106 , 107 opposite the projecting parts 115 , 116 . The indentations 106 , 107 are radially urged into the surface of the inserted tubes 104 , and ensure this way a pressure sealed connection between the coupling sleeve 102 and tube 104 . In this particular embodiment as well the cone shaped enlargements 117 , 118 of the pressure ring 111 are designed in a stepped way. This means, that originating from the end of the pressure ring 111 a greater area of the cone shaped enlargement is followed by a cone shaped neck of less extent. This stepped formation repeats up to the axis of symmetry over the total cone shaped enlargement 117 , 118 . Accordingly, the cone shaped enlargements 119 , 120 of the press rings 112 , 113 are complimentarily formed.
The functional effects of this stepped formation of the opposite surfaces are of importance in two respects. In the pre-pressed condition, the interlocking engagement between the pressure ring 111 , on the one hand, and the press rings 112 , 113 , on the other hand, ensure a cohesion of the individual elements of the assembly, and thus a high degree of pre-fabrication of the tube coupling. In the pressed condition, the same formation ensures to avoid the press rings from sliding back from the pressure ring. Thus, the safety of the tube connection will be increased with most different loads.
In an embodiment formed as shown in FIG. 8 the pressure ring 111 is divided in its radial axis of symmetry D—D into the pressure ring portions 111 ′ and 111 ″. Both pressure ring portions 111 ′ and 111 ″ are coupled with each other by an axial intermediate ring 140 . Then, the intermediate ring 140 has the same inner diameter as the pressure ring portions 111 ′ and 111 ″ in order to push the pressure ring assembly formed of the pressure ring portions 111 ′ and 111 ″ and the intermediate ring 140 over the coupling sleeve 102 having the same length.
The intermediate ring 140 comprises two spaced surrounding flanges 141 ′ and 141 ″ on its outside which serve as a stop for the face directed towards the axis of symmetry D—D of the respective pressure ring portion 111 ′, 111 ″. Moreover, the intermediate ring 140 comprises each an area from the outside directed from the flange 141 ′, 141 ″, respectively, which terminates in an from the outside facing edge 142 ′, 142 ″. The end of the pressure ring portion 111 ′, 111 ″ associated to the edge 142 ′, 142 ″ comprises an area with a diameter which is increased in comparison with the inner diameter, in which a groove 143 ′, 143 ″ is machined which will be engaged with the edge 142 ′, 142 ″. This engagement ensures a pre-mounting state of the two pressure ring portions 111 ′, 111 ″.
The space located between the flanges 141 ′, 141 ″ serves for receiving a pressing tool not shown wherein the pressing tool supports on the flange, on the one hand, and on the outwardly directed face of the associated press ring. The advantage of this modification is in the diminution of the pressing path, and thus of extensive minimization of the pressing tool. The invention will be described according to another embodiment. In this embodiment, the device serves for the pressure sealed connection of two opposite tube ends of the same nominal width in alignment. The tube coupling 201 performed as shown in FIG. 9 restricts to the one side of the device since it is provided symmetrically to the axis A—A.
The tube end 204 will be pushed in from one side into the hollow cylinder shaped coupling sleeve 202 approximately up to its centre. The inner area of the coupling sleeve 202 is provided in the section receiving the tube end 204 with a plurality of radially surrounding teeth 206 being spaced to one another and recessed in comparison with the inner diameter of the coupling sleeve 202 which are directed against the surface of the tube end 204 .
Over this section of the coupling sleeve 202 is pushed a pressure ring 211 the inner diameter of which is slightly greater than the outer diameter of the coupling sleeve 202 . On its outside the pressure ring 211 comprises a cone shaped enlargement 217 , 218 originating from each end and increasing to the centre of the pressure ring 211 .
The pressure ring 211 is associated on each side with a press ring 212 , 213 . Each press ring 212 , 213 is realized on its inside with a cone shaped enlargement 219 , 220 which correspond to the cone shaped enlargements 217 , 218 . In the not pressed position of the device which is characterized with the reference numeral 245 the press rings 212 , 213 are pushed over the respective end area of the pressure ring 211 wherein the cone shaped enlargements ( 217 / 219 , 218 / 220 ) are adjacent in these areas.
From the position 245 the press rings 212 , 213 are shifted against each other over the cone shaped enlargements into the pressed position of the device as illustrated at 246 by means of a tool being not shown. On that occasion, the pressure ring 211 is radially urged into the coupling sleeve 202 which in turn results in a radial displacement of the teeth 206 into the surface of the tube end 204 . In this way, a pressure sealed, non-detachable tube coupling is formed.
A considerable feature of the invention is in that to pre-assemble the single elements of the tube coupling such as the coupling sleeve 202 , pressure ring 211 and press rings 212 , 213 in order to provide them as a compact assembly on the assembly yard. With this, it is necessary for the single elements to be equipped with means which enables a defined positioning of the single elements to one another.
For this reason, the coupling sleeve 202 is formed with radially surrounding grooves 235 on the outside of the section which receives the tube end 204 . The pressure ring 211 on its inside comprises radially surrounding locating features formed as swellings and corresponding to the grooves 235 . The tolerance between the two elements is formed such that with pushing on the pressure ring 212 on the coupling sleeve 202 by means of manual force, the swellings 236 lock into the grooves 235 , and fix the position of the two elements to one another in the pre-pressed condition.
In a similar way, the pressure ring 211 on its outside and the press rings 212 , 213 on its inside are equipped with respective means for positioning to one another.
The pressure ring 211 is equipped with a locating feature 237 , 238 on its cone shaped enlargement 217 , 218 in the proximity of its end, respectively, and with another locating feature 239 , 240 in the proximity of its centre, and the respective press ring 212 , 213 is provided with a locating feature 241 , 242 on its end facing towards the pressure ring 211 on its cone shaped enlargement 219 , 220 formed on the inside, and with another locating feature 243 , 244 on the end facing off the pressure ring 211 .
The locating features correspond to each other in a different way according to the condition of the tube coupling 201 . In the not pressed condition of the tube coupling 201 the locating features 237 , 238 formed on the pressure ring 211 correspond to the locating features 241 , 242 of the press rings 212 , 213 . As a result, all elements of the tube coupling 201 are assembled to a structural unit factory sided which in this compactness can be provided on the assembly yard.
With pressing the tube coupling 201 the engagement of the locating features acting between the pressure ring 211 and the press rings 212 , 213 will be changed such that, on the one hand, the locating features 239 and 240 of the pressure ring 211 come into active relation with the locating features 241 , 242 of the press ring 212 , 213 , and on the other hand, the locating features 237 and 238 of the pressure ring 211 come into active relation with the locating features 243 , 244 of the press ring 212 , 213 . In this way, the press rings 212 , 213 will be prevented from sliding back over the cone shaped formations after pressing and thus endangering the stability under load of the tube coupling 201 .
Another feature of the invention is the construction of the pressure ring 211 . The pressure ring 211 in its cross-section consists of single segments spaced to one another which uniformly enclose the coupling sleeve 202 . For it, the pressure ring 211 will be circumferentially slotted over its total wall thickness in the axial direction wherein preferably between the adjacent segments ridges are left which obtain the shape of the pressure ring 211 . The advantage of this construction is in that with pressing the tube coupling 201 , the work of deformation between the pressure ring 211 and the press rings 212 , 213 will be minimized since the intended and required diminution of the diameter of the pressure ring 211 is firstly realized through closing the slots between adjacent segments, and not through a deformation of the pressure ring 211 . The diameter reduction of the pressure ring 211 by shifting the press rings 212 , 213 against each other transfers to the section of the coupling sleeve 202 which has received the tube end 204 wherein the teeth 206 are urged into the surface of the tube end 204 , and thus ensuring a pressure sealed tube coupling 201 .
Another possibility of spacing the individual segments of the pressure ring 211 to one another in a defined way is in depositing a flexible distance mass between the segments which maintains a uniform distribution of the segments on the circumference of the pressure ring 211 . During pressing the tube coupling the distance mass between the adjacent segments will be pressed out.
The invention provides a tube coupling which ensures highest universality regarding the requirements to the quality of the tubes to be connected. It comprises a calculable behavior and is capable to ensure high pressure sealed tube couplings planewith great tolerances of outer tube diameters.
The solution according to the invention minimizes the forces required for axially pressing the press rings on the pressure ring and thus on the coupling sleeve. It is distinguished by a high stability in comparison with vibrations, axial tensile forces on the tube and extreme fluctuations of temperature.
The tube coupling comprises rotationally symmetrical components to be simply manufactured which enable optimum combinations with regard to the aspired properties of the tube coupling with regard to the functional selection of the employed materials having their specific properties.
The solution according to the invention enables the standardization of the design of the press set.
In connection with different coupling sleeves and embodiments, respectively, one and the same design of press set can be used. Thus, it is also possible to press different outer tube diameters only by constructive adaptation of the coupling sleeve in particular limits.
Although the present invention has been described according to some preferred embodiments which show the connection of two tube ends it will be readily appreciated for one skilled in the art that various modifications and changes can be made without departing from the scope of protection of the following claims. Thus, it can be seen that it is fallen back on the pressing connection carried out according to the invention on one side only, however, the other side is equipped with conventional connecting elements such as, e.g. threaded joints or flanges which merely represents a special embodiment of the invention. | A device for producing a pressure-tight pipe coupling with at least one pipe and comprises a bushing-type, rotationally symmetric base body. The base body is provided with at least one essentially cylindrical inner chamber, having toothed elements in order to receive the pipe end. The toothed elements are displaced radially into the pipe end arranged in the inner chamber by means of a pressing device which impinges upon the outer surface of the base body. A pressing device consisting of a shaping ring and a corresponding pair of shaping rings guarantee that the radial displacement potential is realized in the form of a radial displacement, resulting in significantly lower pressing power. | 5 |
This is a division of application Ser. No. 07/817,034, filed on Dec. 30, 1991.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to stepper motors, and in particular to permanent-magnet sheet-metal type stepper motors.
2. Description of Related Art
Stepper motors include a stator for producing a rotating multipole magnetic field and a multipole rotor for rotating about a central axis of the stator in synchronism with the rotating field. Typically the rotating magnetic field is effected by applying electrical pulses of continually changing phase to respective windings of the stator. Further details of typical stepper motor structure, operation and drive circuitry can be obtained from a publication entitled AIRPAX Stepper Motor Handbook published by Airpax Company, 604 West Johnson Avenue, P.O. Box 590, Cheshire, CT, U.S.A.
Because such a motor is capable of converting electrical pulses into discrete mechanical rotational movements, it is particularly useful for controlling the rotary or linear position of an object coupled to its rotor. An example of one linear application which takes advantage of this capability is illustrated in FIG. 1. This Figure shows a stepper motor 10 which has been made by Airpax Company (part number A95228) for controlling the linear position of a shaped head 12 to control airflow 14 in a throttle body 16 of an internal combustion engine (not shown). The external surface of the head 12 is precisely shaped to conform to a neck surface 18 of the throttle body so that the linear position of the head regulates the magnitude of a clearance between the two surfaces.
Although it is not shown in FIG. 1, the head 12 is attached to a shaft which has a threaded end engaging an internal thread of the rotor in the stator contained in the motor housing 20. The shaft is prevented from rotating with the rotor by means of a separate part which has fingers projecting into respective longitudinal grooves in the shaft. The separate part is attached to an end of the stator, which itself includes a number of parts held together in two outer shell members which are fastened together This arrangement functions well, but is complicated to assemble Such complicated assembly of numbers of individual parts typifies the motor.
SUMMARY OF THE INVENTION
It is an object of the invention to provide a stepper motor of simple modular construction which may be easily and reliably assembled.
In accordance with a first feature of the invention the stator has a central axis and comprises a monolithically-molded assembly including a plurality of multi-pole pieces embedded in a molding of insulating material. The molding defines at least one circumferential winding-holding channel disposed about the axis; an inner, axially-extending opening for receiving at least a portion of the rotor; a first axial end having bearing-holding means; and a second axial end comprising a bearing portion having a bearing surface with a circular cross section and an adjacent shaft anti-rotation portion having an inner surface with a non-circular cross section of predefined shape. The rotor comprises a body including a first end supporting a bearing secured by the bearing-holding means of the stator molding; a second end having a bearing surface disposed for rotation against the bearing portion of the stator; a permanent magnet portion disposed for rotation within the stator; and a threaded surface. The shaft comprises an axially displaceable end extending from the stator and means for cooperating with the rotor and the stator to convert rotational movement of the rotor to axial displacement of the shaft. Such means include a first portion of the shaft having a threaded surface disposed in the rotor body in rotatable engagement with the threaded surface of the rotor body and a second portion of the shaft including an outer surface with a cross section having the predefined shape and being slidably disposed in the shaft anti-rotation portion of the stator molding.
In accordance with a second feature of the invention the rotor comprises a generally cylindrical metallic barrier; a hub formed of a first plastic material molded to an inner surface of the barrier; and a magnet formed of a second plastic material molded to an outer surface of the barrier.
In accordance with a third feature of the invention the motor includes a housing disposed around the stator and a connector means having externally-accessible terminals which are electrically connected to at least one winding of the stator. The stator includes at least one bobbin including first and second sidewalls between which the at least one winding is disposed. The first sidewall is located toward a first axial end of the stator, has a peripheral portion with at least one notch of predetermined depth, and the housing extends over the peripheral portion of the first sidewall. The connector means comprises an insulating body molded around the terminals. Each of the terminals has a first part which is accessible externally of the stepper motor and a second part extending through the at least one notch transversely of the first sidewall. Each terminal is electrically connected to a wire forming the at least one winding. The predetermined depth of the notch is sufficiently large to ensure that a clearance exists between the second part of the terminal and the housing.
In accordance with a fourth feature of the invention the motor also includes a housing disposed around the stator and a connector means having externally-accessible terminals which are electrically connected to at least one winding of the stator. The stator comprises at least one bobbin having first and second sidewalls including respective plates of magnetically-permeable material between which the at least one winding is disposed. The housing comprises magnetically-permeable material and includes a plurality of portions which are deformed into respective regions between the first and second sidewalls of the at least one bobbin to force the housing into contact with the plates and provide a decreased-reluctance magnetic return path for a magnetic field produced by said at least one winding.
In accordance with a fifth feature of the invention the motor includes a housing disposed around the stator and a shaft coupled to the rotor such that rotation of the rotor effects linear motion of the shaft. The shaft extends axially out of an opening in a tubular end of the stator and includes first and second ends. The first end is coupled to the rotor and the second end is attached to an operative member. The tubular end of the stator has an outer surface of predefined cross-sectional shape. A tubular member having the same cross-sectional shape extends axially from the operative member and around the tubular portion of the stator. The tubular member, the tubular end of the stator and the opening in the tubular end define a labyrinthal path that inhibits the passage of contaminants from outside of the motor into the rotor.
In accordance with a sixth feature of the invention the motor also includes a housing disposed around the stator and includes means for mounting the motor. The mounting means comprise a cylindrical end portion of the housing having a central axis and a mounting flange rotatably attached to the cylindrical end portion. The end portion includes, in sequence, a first circumferential region including first means for pressing against a rigid surface of an object to which the motor is to be mounted; a second circumferential region including second means projecting from an outer surface of the cylindrical end portion to a predetermined radial distance from the central axis; and a third circumferential region having a predetermined outer diameter. The mounting flange has a circular opening defined by a bevelled inner surface which increases in diameter from the third region toward the second region. The bevelled inner surface engages the second means and locks the flange against rotation when the flange is axially forced toward the first region.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 shows a typical application of a stepper motor having a linearly-movable shaft.
FIG. 2 is an exploded view, partly in cross section of a stepper motor constructed in accordance with the invention.
FIG. 3 is a side view, largely in cross section, of the assembled stepper motor of FIG. 2.
FIG. 4 is a side view, in cross section, of a stator incorporated in the stepper motor of FIG. 2.
FIGS. 5a and 5b are end and side views, respectively, of a stator pole piece incorporated in the stator of FIG. 4.
FIGS. 6a through 6d are side views, in cross section, showing successive steps in the manufacture of a rotor and bearing assembly incorporated in the stepper motor of FIG. 2.
FIG. 7 is a side view of a shaft incorporated in the stepper motor of FIG. 2.
FIG. 8 is a top view of a portion of the stepper motor of FIG. 3.
FIGS. 9a, 9b, 9c, and 9d are side views of end portions of electrical terminals shown in FIG. 8.
FIG. 10 is a cross-sectional view of the stepper motor of FIG. 3, taken along the section 10--10.
FIG. 11 is a bottom, cross-sectional view of a housing and flange portion of the motor of FIG. 3.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 2 illustrates the component parts of a stepper motor constructed in accordance with the invention. The parts, which are assembled along a central axis x--x of the motor, include a shaft 22, a flange 24, a housing 26, a stator 28, a rotor 30, a ball bearing 32, a elastomer O-ring seal 34, and an electrical connector 36. The assembled stepper motor is illustrated in FIG. 3.
The stator 28, which serves as a central building block of the stepper motor, is separately illustrated in FIG. 4. One of four identical pole plates incorporated in the stator is shown in end view in FIG. 5a and in front view in FIG. 5b. Each pole plate includes a number of integral poles (six in this exemplary motor). The stator is a monolithically-molded assembly which is formed by injection molding a plastic material such as polybutylene terephthalate around the four pole plates 38a, 38b, 38c, 38d. The pole plates are arranged in two pairs 38a, 38b and 38c, 38d, which are overmolded to form two respective molded bobbins 40 and 42. The two pole pieces are arranged with respect to each other such that their poles intermesh, but do not touch, as is well known in the art.
The stator molding is hollow and includes respective portions defining an opening 44 at a first end for closely holding the bearing 32, a central opening 46 within the pole pieces for receiving a central, magnetic portion of the rotor 30, and first and second functional openings 48 and 50 at a second end. First opening 48 receives a cylindrical end 52 of the rotor 30 and has an inner surface which cooperates with an outer surface of the end 52 to form a journal bearing. Second opening 50 slidably receives a portion 54 of the shaft 22 and has a non-circular shape (when viewed along the axis x--x) which corresponds with that of the shaft portion 54. This shape must be non-circular to prevent rotation of the shaft with the rotor, and in the preferred embodiment opening 50 and shaft portion 54 are substantially square.
The rotor is illustrated in detail in FIGS. 6a through 6d, which show successive steps in its manufacture. These steps are described in the following, correspondingly-lettered paragraphs:
a. A generally-cylindrical barrier member 56 is cold formed from a metal such as aluminum. The use of the barrier member strengthens the rotor and enables different materials to be either simultaneously or sequentially molded to the inner and outer surfaces of the member. The barrier member includes an indentation 58 for preventing rotary and axial movement of moldings formed on its inner and outer surfaces. Alternatively, a perforation may be forced through the barrier member. It also includes a reduced-diameter end portion 60 for receiving the bearing 32.
b. A hub 62 is injection molded within the barrier 56 from a plastic such as polybutylene terephthalate, with a protruding cylindrical end portion 52 (which is received in the stator opening 48 to form the journal bearing). A thread 64 is molded into a central portion of the hub to rotatably engage a corresponding thread 66 on an end portion of the shaft 22. These engaging threads effect a linear displacement of the shaft along axis x--x when the rotor is rotated.
c. A highly-permanent-magnet material, such as a mixture of barium ferrite and a thermoplastic (e.g. nylon) is injection molded around the outer surface of the barrier member 56 to form a cylindrical permanent magnet 68. The magnet is magnetized either during or after the molding process in such a way as to permanently impress a number of poles disposed radially along the magnet's periphery to form pole pairs. In this exemplary embodiment there are six pole pairs.
d. The ball bearing 32 is attached to the reduced diameter end 60 of the barrier member. It is secured to the barrier member by bending the edge of end 60 away from the axis x--x.
An embodiment of the shaft 22 is illustrated in detail in FIG. 7. This embodiment is substantially identical to that shown in FIGS. 2 and 3, except that a head 70a disposed at one end of the shaft has a slightly different outer contour than a head 70b shown in those figures. The head is used in throttle body applications and the actual contour used depends on the design of the specific throttle body in which it is used.
The shaft includes a central, threaded metal rod onto which the portion 54 and the head 70(a,b) are injection molded from a plastic material such as polyphenylene sulfide. Preferably portion 54 and head 70(a,b) are molded as a single unit, as is best shown in FIG. 2. The shaft also includes a tubular metal shield 72 which has a funnel-shaped end portion 74 embedded in the head 70(a,b). Preferably the end portion 74 substantially conforms to the shape of the head, to prevent deformation of the outer surface of the head resulting from shrinkage during cooling of the molding. End portion 74 also includes a number (e.g., three) of tabs 76 which are punched inwardly from the metal shield, leaving perforations through which the plastic material forming the head flows during molding. The tabs strengthen the rigid connection between the head and the shield, and the perforations ensure continuity of the molding material on opposite sides of the funnel-shaped portion 74.
The primary function of the shield 72 is to cooperate with the stator 28 in preventing contaminants such as dirt and grime from entering the motor. As can best be seen in FIG. 3, the stator molding has at one end an outwardly extending portion 78 with the same shape as the shield, which is circular in the preferred embodiment. The portion 78 has an outside diameter which substantially matches the inside diameter of the shield. The shield, in cooperation with the extending portion 78, presents a long labyrinthal path that inhibits the entrance of contaminants into the rotor. The end of the shield disposed in the housing is flared outwardly to increase the length of the labyrinthal path and to increase the strength of the shield.
Referring to FIGS. 3, 6d and 7, the shaft also includes a circular plastic portion 80 which is integrally molded onto the threaded rod with the portion 54. Portion 80 includes an outwardly-projecting integral stop 80a which cooperates with a corresponding stop 82 molded onto an inner surface of the rotor hub 62. The two stops have axially-extending faces which are positioned such that they meet and stop rotor rotation if the shaft is drawn into the motor to a position where the flared end of the shield would otherwise be pulled against the proximal stator molding surface. This avoids excessive loading of the motor which could be required to drive the shaft out of the stator if the shield binds against the stator molding.
FIGS. 3, 4 and 8 illustrate attachment and electrical connection of the connector 36 to the stator 28. The connector is a molding of electrical insulating material, such as polyethylene terephthalate in which four electrical terminals 84a, 84b, 84c, and 84d are embedded. The terminals pass through the molding from an access port 86, for receiving a mating electrical connector (not shown), to a face which lies adjacent a sidewall of stator bobbin 42. This sidewall, in which the pole plate 38d is embedded, is notched in a region 88 to provide a receiving space for ends of the terminals. The integrally-molded sidewalls of the two bobbins, in which the pole plates 38b and 38c are embedded, are also notched in a region 90 to provide a passage to the terminal ends for the ends of a first winding 92 of insulated magnet wire wound on the bobbin 40. Similarly, a second winding 94 is provided on bobbin 42.
The method of attaching the connector and making the electrical connections will be made clear by referring to FIGS. 2, 8 and 9. The facing surfaces of the connector 36 and the stator 28 are affixed to each other, preferably by ultrasonic welding. Initially, the ends of the terminals are oriented substantially parallel to the facing surfaces, extending away from the axis x--x, to facilitate electrical connection of the windings. As is illustrated in FIG. 9, the terminal ends have respective thickened portions 96a, 96b, 96c, and 96d for preventing the wire ends of the windings from slipping off of the terminals.
Each of the wire ends is first wrapped around a portion of the respective terminal disposed between the connector body and the thickened portion, and is then wrapped around the distal end of the terminal. The terminal ends and the attached wires are then dip soldered or welded and bent down into the notched region 88 far enough to avoid contact with the winding and to provide an electrically-insulating clearance between the bent terminal ends and the housing, when it is attached to the stator. There is no possibility of the terminal ends or the end wires of winding 92 contacting pole plates 38b, 38c or 38d, respectively, because each of these pole plates is oriented in the stator molding with a respective flattened portion 98 located under the regions where the notched areas are formed. (See FIG. 5a)
As is illustrated in FIG. 3, the housing 26 is assembled over the stator 28 and over one end of the electrical connector 36 which includes a peripheral portion defining a channel in which the elastomer 0-ring seal 34 is disposed. The housing is secured by bending an end portion 100 over the peripheral portion. It has been found that the operating efficiency of the motor is significantly improved by deforming small portions of the housing, made of a metal of good magnetic permeability such as low-carbon steel, into spaces above the windings to ensure that the housing contacts each of the pole plates. Only two of these indentations 102, 104 are visible in FIG. 3, but in the preferred embodiment several (e.g. three) such indentations 104 (see FIG. 10) are formed in the housing around each winding. This arrangement provides low reluctance return paths for the magnetic fields produced by the windings when they are energized.
As is best seen in FIGS. 10 and 5a, the housing further includes at least one indentation 106 which is located to engage aligned, corresponding indentations 108 in the embedded pole plates 38b and 38c to secure the housing against rotation with respect to the stator. It is not necessary that all of the indentations 108 in the pole plates be utilized.
FIG. 11 illustrates mounting means by which the stepper motor is attached to a body, such as the throttle body of FIG. 1, at any desired rotational position around the axis x--x. The mounting means includes the flange 24 and a cylindrical end portion of the housing 26, which are both shaped to secure the motor to the body at the desired rotational position.
The cylindrical end portion includes a first circumferential region having a number of projecting indentations 110, a second circumferential region having a number of projecting indentations 112, and a third circumferential region 114 having a smooth outer surface of radius R. The indentations 110 and 112 are evenly spaced around the cylindrical end portion, e.g. at intervals of sixty degrees.
The flange 24 has a circular opening defined by a bevelled inner surface 116 which increases in radius from a magnitude slightly greater than R, where it contacts the third circumferential region 114, to a radius slightly greater than the distance by which the indentations 112 protrude from the axis x--x. The indentations 110 are dimensioned and positioned to press against a circumferential surface 118 in the body when the flange 24 is pressed against an outer surface of the body and mounted by means such as bolts (not shown) passing through holes 120 and 122. This action also forces the projecting indentations 110 into circumferential surface 118 of the body and the projecting indentations 112 to compress against the bevelled surface 116 of the flange.
Before the indentations 112 and 110 are forced into the respective surfaces 116 and 118, the flange is free to rotate about the housing. This enables the flange to be readily adjusted to any angular position which will make the access port 86 of the connector 36 accessible to a mating connector. After the indentations 112 and 110 are forced into the respective surfaces 116 and 118, nor further rotation is possible. The indentations 112 and 110 projecting from the cylindrical end portion act as spring members when forced against the respective surfaces of the flange and the body, thus allowing repetitive mounting to the body without losing the locking ability. | A stepper motor of the permanent-magnet sheet-metal type is constructed of a number of modules, simplifying assembly. The modular parts include a stator having integrally-molded winding bobbins and pole pieces. A rotor mounted in the stator includes a barrier member which separates a plastic, threaded hub molded interiorly from a permanent magnet molded exteriorly. A shaft having a first threaded end rotatably engaged with the interior of the rotor hub has a rectangular central portion extending through a rectangular opening of the stator to convert rotary motion of the rotor to linear motion of the shaft. An opposite end of the shaft includes a molded head and a tubular shield extending from the head. This shield and a tubular portion of the stator molding define a labyrinthal passage which inhibits the passage of contaminants into the rotor. A housing of the motor and a rotatably attached flange include engagable portions to lock the flange at a desired angular position. | 7 |
BACKGROUND INFORMATION
1. Field of the Invention
The invention relates generally to the field of threaded fasteners. More particularly, the invention relates to a threaded insert for repairing threads in a bore. More particularly yet, the invention relates to a tool for installing a threaded insert with locking keys into a tapped bore.
2. Description of the Prior Art
Threaded inserts are commonly used to repair or strengthen tapped bores. For example, it is sometimes necessary to repair threads in a bore because the threads have become stripped or otherwise damaged. Thread repair generally comprises the steps of drilling out the damaged threads, tapping the bore to a larger diameter, and threading a threaded insert into the bore to provide an internal threaded diameter that will receive and securely hold the threaded fastener. Often, a threaded insert is used to strengthen a bore made of material that is otherwise too soft to securely hold a threaded fastener, particularly one that is repeatedly inserted and removed. In this case, a threaded insert of hardened material is inserted into a tapped bore of softer material to provide a rugged and durable threaded bore.
In order to install a threaded insert, the insert is properly aligned with the longitudinal axis of the tapped bore, screwed into the bore, and secured. One conventional method of securing the insert in the bore is to provide the threaded insert with locking keys. The conventional insert generally has two or four locking keys that extend upward from keyways that are evenly spaced around the outer perimeter of the insert. After the threaded insert has been threaded into the bore, the locking keys are driven down into keyways, forcing the keys to bite into material in the insert and in the bore, thereby securing the insert against radial movement. One common difficulty with installing the threaded insert is that the locking keys are relatively slender and are in danger of being bent, splayed, or damaged when the insert is screwed into the tapped bore.
Conventional tools for inserting threaded inserts generally comprise several components that move relative to one another and cooperate together to perform the various operations required to properly install the insert. Such a tool is disclosed by Schron et al. (U.S. Pat. No. 5,617,623; 1997). The tool has a drive means, a body, and a press. The body of the tool has a first end with an external threaded shaft onto which the drive means is threaded and a second end with an external threaded shaft onto which the press is threaded. A sleeve encircles the press and is movable relative to the press. A thrust bearing is assembled on the body above the press. The external threads on the threaded shaft on the second end mate with the internal threads on the repair insert, which is rotated down into the tapped bore until the locking keys on the insert hit against the impact face of the press. The drive means is a handle that is used to rotate the body to thread the insert into the tapped bore. The sleeve is moved longitudinally down toward the insert over the locking keys. The socket of a power tool is then placed on the drive means and a rotational force applied to the drive means, which drives the body, the press, and the insert rotationally, threading the insert into the tapped bore and then forcing the locking keys down into the keyways along the outer side of the insert.
The fact that the threaded insert tool of the type disclosed by Schron et al. is constructed of individual parts, some of which move relative to each other in the process of executing the task of inserting a threaded insert, is a disadvantage. The individual parts must be machined with a relatively high degree of precision to ensure that they will function properly together and they must be assembled. The required manufacturing and assembly processes increase the cost of producing such a tool. A tool that comprises multiple moving or cooperating parts also inherently provides sources of tool failure, the failures arising from worn parts that no longer function properly or contamination between parts that prevents them from moving or cooperating properly. As is generally known, threaded inserts are often used in an environment that is laden with contaminants, such as in a machine shop or a car repair shop, and care must be taken to keep the insert repair tool free of dirt and other contaminants.
A single-body insert tool, such as the tool distributed by the Christopher Company for installing ROCK SOLID INSERTS, eliminates some of the disadvantages of other conventional tools, in that it has no moving or cooperating parts. The tool is a cylindrical body with a strike end and an insertion end. A pilot extends from the insertion end for guiding the tool onto the threaded insert. Keyways are provided around the outer perimeter of the insertion end for receiving the locking keys of the threaded insert. A continuous circular groove, concentric to the pilot, is machined into the face of the insertion end. The threaded insert is placed over the pilot such that the locking keys of the threaded insert are secured in the tool keyways. The insert is screwed into the tapped bore, the insert tool lifted slightly and rotated about its longitudinal axis so that the upper ends of the locking keys slide into the groove. An impact force is applied to the strike end of the tool to drive the locking keys into the keyways provided on the threaded insert. Once the tool has been forced down onto the threaded insert as far as it can go, the tool is lifted from the insert. At this point, the upper ends of the locking keys protrude upward beyond the upper edge of the threaded insert. In order to drive the locking keys flush with the upper edge of the insert, the endface of the pilot is placed on a locking key and an impact force applied to the strike end of the tool. Typically, a threaded insert has four locking keys, and the step of driving the locking key flush with the upper edge of the insert is repeated for each locking key.
The disadvantage of the conventional single-body tool is that each locking key must be driven down into the tapped bore individually. This requires repetitive installation steps and also increases the risk that the person installing the insert will accidentally pinch or injure himself during the installation. A further disadvantage of this tool is that it does not correct for a misalignment of the locking key. A misaligned key makes it very difficult, if not impossible, to drive the key properly into the keyway on the insert in the tapped bore.
What is needed, therefore, is a threaded insert tool that provides a means of inserting a threaded insert with locking keys into a tapped bore while simultaneously protecting the locking keys. What is further needed is such a device that corrects a misalignment of the locking keys. What is yet further needed is such a device that simultaneously drives all the locking keys completely into the threaded insert.
BRIEF SUMMARY OF THE INVENTION
It is an object of the present invention to provide a threaded insert tool that properly aligns and inserts a threaded insert into a tapped bore, while simultaneously protecting the locking keys from damage. It is further an object to provide such a tool that corrects a misalignment of the locking keys. It is a yet further object to provide such a tool simultaneously drives all the locking keys completely into the threaded insert so that the upper ends of the keys are flush with the upper edge of the insert.
The objects are achieved by providing a single-component threaded insert tool. The threaded insert tool according to the invention comprises a body with an insertion end for threading the insert into a threaded bore and a strike end for receiving impact blows. The insertion end of the tool has an insertion face, tool keyways evenly spaced around the outer perimeter of the insertion end. A cylindrical pilot or guide extends from the insertion end, coaxial to the longitudinal axis of the tool, and guides the tool into the insert. Key-retaining means are provided on the insertion face. The tool keyways are adapted to receive and engage the locking keys of the insert when the insert is slipped over the pilot in preparation for installation. The key-retaining means may be an individual bore provided for each locking key or a partial circular groove that opens from each tool keyway. The key-retaining means according to the invention may also include an alignment means to re-align misaligned locking keys. In this case, the key-retaining means is provided with a contoured inner surface that urges the locking key into proper alignment when the insert tool is forced down against the locking keys during installation of the insert. A timing mark may be provided on the outer perimeter of the insert tool to aid in ensuring that a flat strike surface is provided above each of the locking keys for driving them simultaneously down into the insert. It is noted that the threaded insert tool according to the invention is dimensioned to receive and install a threaded insert of a particular size that has two or four locking keys. Thus, the outer diameter of the pilot corresponds to the inner thread diameter of the threaded insert, and the length of the pilot corresponds approximately to the length of the insert, and the outer diameter of the insertion face corresponds to the diameter of the upper face of the outer thread on the threaded insert.
Installation of a threaded insert using the threaded insert tool according to the invention is as follows: The threaded insert is placed on the pilot and moved toward the body of the tool so that the locking keys are received into the corresponding tool keyways. The threaded insert is then placed in the tapped bore and the tool rotated to screw the insert down into the tapped bore. The tool may be rotated manually or with a power tool.
Once the insert is threaded into the bore to the desired depth, the tool is lifted up from the insert until the locking keys are free of the tool keyways. The tool is then rotated slightly and lowered over the insert such that the upper end of each key is received into the corresponding key-retaining means. An impact force is applied to the strike end of the tool that is sufficient to drive the keys down along the sides of the threaded insert in the tapped bore. A hammer or other suitable tool is used to apply the impact force to the strike end. Once the face of the insertion end of the tool is flush with the upper surface of the threaded insert, the tool is lifted off the keys and rotated until the timing mark aligns with one of the keys. The insertion face now provides a flat strike surface above each of the locking keys. An impact force is again applied to the strike end of the tool with sufficient force to simultaneously drive the keys down into the bore until the upper ends of the keys are flush with the upper edge of the insert.
The device according to the invention is suitable for manual and automated insertion of threaded inserts. The body of the tool may be contoured to enable location of the tool within a jig in an automated manufacturing or assembly process. As mentioned above, a hammer or other suitable tool is used to strike the tool and thereby drive the keys down into the bore.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an illustration of a conventional threaded insert with locking keys (prior art).
FIG. 2 is a side view of a first embodiment of the threaded insert tool according to the invention.
FIG. 3 is a plane view of the insertion end of the tool of FIG. 1, illustrating four keyways for receiving locking keys and four key-retaining alignment bores.
FIG. 4 is a detail illustration of the key-retaining alignment bore.
FIG. 5 is an elevational view of the tool of FIG. 2, illustrating the placement of a threaded insert on the pilot and insertion of the locking keys into the tool keyways.
FIG. 6 is an elevational view of the tool of FIG. 5, showing the threaded insert threaded into the bore and the upper ends of the keys in the key-retaining alignment bores on the tool.
FIG. 7 is an elevational view of the tool of FIG. 5, showing the timing mark aligned with a locking key and the locking keys driven all the way into the tapped bore.
FIG. 8 is a plane view of the insertion end of a second embodiment of the threaded insert tool according to the invention, showing a partial circular groove that serves as a key-retaining alignment means.
FIG. 9 is a plane view of the insertion end of a conventional threaded insert tool having a continuous circular groove that serves as a key-retaining means. (Prior Art)
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a conventional threaded insert 8 . The particular embodiment shown has four locking keys 9 and insert keyways 8 B; another conventional embodiment of the same type of threaded insert 8 has two locking keys 9 .
FIGS. 2 through 4 illustrate the preferred embodiment of a threaded insert tool 100 according to the invention that is used to install the threaded insert 8 into a threaded bore. As shown in FIG. 2, the tool 100 comprises a body 1 , having an insertion end 4 with an insertion face 4 A and a strike end 5 . The insertion end 4 includes an insertion pilot 2 that extends outward from the insertion face 4 A, coaxially to the longitudinal axis of the body 1 . Tool keyways 3 are provided on the outer perimeter of the insertion end 4 and a timing mark 14 , as shown.
In the embodiment shown, a knurled surface is indicated on the recessed portion of the body 1 . This may be desirable for manual operation of the tool 100 . Also, the embodiment of the tool 100 is shown as a substantially cylindrically-shaped tool. These features are not to be considered limitations on the invention. The outer shape of the body 1 of the threaded insert tool 100 according to the invention may have any suitable shape. Particularly when used in an automated process, it may be desirable that the body 1 of the threaded insert tool 100 be rectangular or octagonal in shape, or have a locating indentation. The preferred embodiment of the threaded insert tool 100 is made of surface-hardened steel. It shall be understood that any material that is suitable for the particular intended application of the tool may be used.
FIG. 3 shows the insertion face 4 A and the pilot 2 of the insertion end 4 , as well as the placement of four keyways 3 , the timing mark 14 , and four key-retaining means 6 . The tool keyways 3 are spaced 90° apart from each other around the outer perimeter of the insertion end 4 and are dimensioned such that the locking keys 9 provided on the conventional threaded inserts 8 are receivable therein. In the embodiment shown, the key-retaining means 6 are shown to be individual depressions or bores, with each depression placed near a tool keyway 3 . It is a matter of convenience and efficiency to place the depressions close to the tool keyways 3 , as will become clear below in the description of the use of the tool 100 . This is, however, not necessary. The primary purpose of the key-retaining means 6 is to receive the upper ends of the threaded-insert locking keys 9 so as to properly locate the tool 1 above the locking keys 9 and to protect the locking keys 9 while the threaded insert 8 is screwed down into the threaded bore. Thus, it is not necessary to have individual depressions as the key-retaining means 6 , rather, the key-retaining means 6 may be configured as partial circular key-retaining slots or grooves that extend from the corresponding tool keyways 3 , as will be discussed below with reference to FIG. 8 .
In the preferred embodiment, the key-retaining means 6 is an alignment bore 13 that, in addition to properly locating the tool 1 on the threaded insert 8 , also serves to correct a misalignment of one or more locking keys 9 . FIG. 4 is an illustration of the alignment bore 13 , showing a guide surface 13 A in the bore 13 that serves to urge the locking key 9 into proper alignment.
FIG. 5 shows the threaded insert 8 partially screwed into a tapped bore 11 in a workpiece 12 . The threaded insert 8 with locking keys 9 has been placed over the pilot 2 of the tool 100 so that an upper end 8 A of the insert 8 abuts the insertion face 4 A of the tool 100 and the locking keys 9 are received and engaged in the tool keyways 3 .
FIG. 6 shows the threaded insert 8 screwed completely down into the tapped bore 11 and with the locking keys 9 pounded down into the bore 11 in the insert keyways 8 B provided in the insert 8 . The upper ends of the locking keys 9 are protruding into the key-retaining alignment means 6 on the insertion end 4 of the tool 100 . In the embodiment shown, the key-retaining alignment means 6 are the alignment bores 13 .
FIG. 7 shows the tool 100 rotated so that the timing mark 14 is aligned with one of the locking keys 9 . The locking keys 9 have been driven down into the tapped bore 11 by applying an impact force to the strike end 5 of the tool 100 and have bitten into the threads in the bore 11 , as shown at 11 A.
FIG. 8 illustrates an alternative embodiment of the threaded insert tool 101 according to the invention. (All features of the tool 101 that are identical to those of tool 100 have the same reference designations.) The key-retaining means 6 is shown as a partial circular groove 16 on the insertion face 4 A. The partial circular groove 16 opens from the tool keyway 3 such that the locking key 9 is receivable in the groove 16 when the tool 101 is rotated slightly. This illustration of the threaded insert tool 101 that is adapted to install a threaded insert 8 having only two locking keys 9 is for illustration purposes only. It should be understood that the key-retaining means 6 shown here is also applicable to an insert tool that is adapted to receive an insert 8 having four locking keys 9 .
FIG. 9 (prior art) shows a continuous groove 7 on the insertion face of a known tool 200 . The diameter of the groove 7 is such that the two or four locking keys on the threaded insert 8 are receivable in the groove 7 when the tool 101 is lifted sufficiently to accommodate the length of locking keys 9 and rotated so that the locking keys 9 move into the groove 7 . Because the continuous groove 7 forms a complete concentric circle, it is not possible to use the insertion face 4 A of the tool 200 to drive the locking keys 9 into the bore 11 , as is done with the preferred and the alternative embodiments of the threaded insert tool 100 / 101 according to the invention. Rather, the end face of the insertion pilot 2 is used as a punch to drive each locking key 9 individually into the bore 11 .
The process of installing the threaded insert 8 with the tool 100 or 101 according to the invention is as follows. The threaded insert 8 is slid onto the pilot 2 , moved toward the insertion face 4 A of the tool 100 , 101 , and simultaneously rotated as necessary until the locking keys 9 on the insert 8 are received in the corresponding tool keyways 3 on the body 1 . The lower end of the threaded insert 8 is then inserted and screwed into the bore 11 , as shown in FIG. 5, by rotating the body 1 of the tool 100 , 101 accordingly. The tool 100 , 101 is rotated until the insert 8 is completely threaded into the bore 11 . The tool 100 , 101 is then lifted upward from the insert 8 until the locking keys 9 are released from the tool keyways 3 . The body 1 is rotated and lowered toward the insert 8 so that the upper ends of the locking keys 9 are received into the key-retaining means 6 on the face 4 A of the insertion end 4 of the tool 100 , 101 . A suitable impact tool is now used to provide an impact force against the strike end 5 of the tool 1100 , 101 that is sufficient to drive the locking keys 9 down into the tapped bore 11 . As the locking keys 9 are driven down into the bore 11 , the insertion face 4 A approaches the upper edge of the threaded insert 8 . When the locking keys 9 cannot be forced any lower into the bore 11 , the tool 100 , 101 is lifted from the insert 8 so that the locking keys 9 are no longer engaged in the tool keyways 3 and rotated until the timing mark 14 is aligned with one of the locking keys 9 . The alignment of the timing mark 14 with the locking key 9 ensures that a flat face 4 A on the insertion end of the tool 100 , 101 is provided above each one of the locking keys 9 . Again, an impact force is applied to the strike end 5 of the tool 100 , 101 , thereby forcing the upper ends of the locking keys 9 down into the bore until they are flush with the upper edge 8 A of the threaded insert 8 .
The embodiments of the invention mentioned herein are merely illustrative of the present invention. It should be understood that a person skilled in the art may contemplate many variations in construction of the present invention in view of the following claims without straying from the intended scope and field of the invention herein disclosed. | A single component tool for installing a threaded insert with locking keys in a tapped bore. The tool has no moving parts and enables simultaneous driving of the locking keys into the tapped bore, flush with the upper edge of the threaded insert in the tapped bore. The tool has a pilot that is inserted into the inner bore of the insert and a plurality of tool keyways for receiving the locking keyways of the insert. Bores are provided in one face of the tool for retaining and aligning the locking-keys while the keys are driven into the tapped bore. A timing mark provided on the tool aids in aligning the tool to simultaneously drive the locking keys flush with the upper edge of the threaded insert. | 5 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] The present application is a continuation-in-part application of U.S. patent application Ser. No. 09/226,204, filed Jan. 7, 1999. The above-listed application Ser. No. 09/226,204 is commonly assigned with the present invention and the entire content of which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention is related to a biocompatible low modulus high strength titanium-niobium alloy, and in particular to a biocompatible Ti—Nb alloy having a major phase of α″ suitable for making a medical implant.
BACKGROUND OF THE INVENTION
[0003] Titanium and titanium alloys have been popularly used in many medical applications due to their light weight, excellent mechanical performance and corrosion resistance. The relatively low strength commercially pure titanium (c.p. Ti) is currently used as dental implant, crown and bridge, as well as denture framework. With a much higher strength than c.p. Ti, Ti-6Al-4V alloy has been widely used in a variety of stress-bearing orthopedic applications, such as hip prosthesis and artificial knee joint. Moreover, the lower elastic modulus allows the titanium alloy to more closely approximate the stiffness of bone for use in orthopedic devices compared to alternative stainless steel and cobalt-chrome alloys in orthopedic implants. Thus, devices formed from the titanium alloy produce less bone stress shielding and consequently interfere less with bone viability.
[0004] Various attempts at providing low modulus, high strength titanium alloys for making medical implants with less stress shielding have been proffered by the prior art. There is still a need in the industry for a lower modulus and higher strength titanium alloys. In addition, studies have reported that the release of Al and V ions from the medical implants might cause some long-term health problems, for example the low wear resistance of Ti-6Al-4V alloy could accelerate the release of such harmful ions. Therefore, a titanium alloy free from potential harmful components is also an important goal of the present invention.
SUMMARY OF THE INVENTION
[0005] The present invention provides a biocompatible low modulus high strength titanium-niobium (Ti—Nb) alloy containing α″ phase as a major phase and consisting essentially of 10-30 wt % of Nb, preferably 13-28 wt % of Nb, and the balance titanium.
[0006] The Ti—Nb alloy of the present invention may further comprises one or more incidental impurities selected from the group consisting of carbon, oxygen and nitrogen, wherein a total amount of said one or more incidental impurities is less than 1 wt %.
[0007] The present invention also discloses a medical implant made of the titanium-niobium alloy of the present invention.
[0008] Preferably, the medical implant of the present invention is an orthopedic implant.
[0009] Preferably, the medical implant of the present invention is a dental implant, dental crown, dental bridge or a denture framework.
[0010] The present invention further provides a method of treating a patient requiring bone or dental prosthesis comprising implanting the orthopedic implant or dental implant of the present invention into said patient.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] The invention will be described in conjunction with the following drawings wherein:
[0012] [0012]FIG. 1 shows X-ray diffraction spectra of the c.p. Ti and the binary Ti—Nb alloys of the present invention, Ti-5Nb, Ti-10Nb, Ti-15Nb, Ti-17.5Nb, Ti-20Nb, Ti-22.5Nb, Ti-25Nb, Ti-27.5Nb, Ti-30Nb, and Ti-35Nb, at a scanning speed of 1°/min;
[0013] [0013]FIG. 2 is a plot showin, the bending strength of the c.p. Ti and the binary Ti—Nb alloys of the present invention, Ti-5Nb, Ti-10Nb, Ti-15Nb, Ti-17.5Nb, Ti-20Nb, Ti-22.5Nb, Ti-25Nb, Ti-27.5Nb, Ti-30Nb, and Ti-35Nb;
[0014] [0014]FIG. 3 is a plot showing the elastic modulus of the c.p. Ti and the binary Ti—Nb alloys ofthe present invention, Ti-5Nb, Ti-10Nb, Ti-15Nb, Ti-17.5Nb, Ti-20Nb, Ti-22.5Nb, Ti-25Nb, Ti-27.5Nb, Ti-30Nb, and Ti-35Nb; and
[0015] [0015]FIG. 4 is a plot showing the microhardness of the c.p. Ti and the binary Ti—Nb alloys of the present invention, Ti-5Nb, Ti-10Nb, Ti-15Nb, Ti-17.5Nb, Ti-20Nb, Ti-22.5Nb, Ti-25Nb, Ti-27.5Nb, Ti-30Nb, and Ti-35Nb.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0016] In the present invention we have prepared Ti—Nb alloys having 5 wt % to 35 wt % of niobium (Nb). Each Ti—Nb alloy was prepared by using the same procedures except that the amounts of the components were different. A comprehensive preparation procedures of Ti—Nb alloy containing Nb 17.5 wt % together with the analysis of the Ti—Nb alloys will be described in the following examples, that are intended as illustrative only since numerous modifications and variations therein will be apparent to those skilled in the art.
EXAMPLES
[0017] Ti—Nb alloy containing 17.5 wt % of Nb and the balance Ti was prepared from a commercially pure titanium (c.p. Ti) bar, and niobium wire using a commercial arc-melting vacuum-pressure type casting system (Castmatic, Iwatani Corp., Japan). The melting chamber was first evacuated and purged with argon. An argon pressure of 1.5 kgf/cm 2 was maintained during melting. Appropriate amounts of the c.p. Ti bar and niobium wire (82.5 wt % Ti-17.5 wt % Nb) were melted in a U-shaped copper hearth with a tungsten electrode. The ingot was re-melted three times to improve chemical homogeneity.
[0018] Prior to casting, the ingot was re-melted again in an open-based copper hearth under an argon pressure of 1.5 kgf/cm 2 . The molten alloy instantly dropped from the open-based copper hearth into a graphite mold located in a second chamber at room temperature because of the pressure difference between the two chambers.
[0019] Various Ti—Nb alloys were also prepared according to the aforesaid procedures. Table 1 lists the weight percentages of the starting metals in the preparation and the concentrations of the resultant alloys determined by EDS (energy dispersive spectroscopy).
TABLE 1 Niobium concentrations of Ti-Nb alloys prepared Starting weight Sample code percentage of Nb Nb concentration (wt %)* Ti-5 Nb 5 wt % 5.08 ± 0.20 Ti-10 Nb 10 wt % 10.32 ± 0.35 Ti-15 Nb 15 wt % 13.66 ± 0.22 Ti-17.5 Nb 17.5 wt % 17.97 ± 0.52 Ti-20 Nb 20 wt % 20.76 ± 1.58 Ti-22.5 Nb 22.5 wt % 22.37 ± 1.02 Ti-25 Nb 25 wt % 24.09 ± 1.23 Ti-27.5 Nb 27.5 wt % 26.65 ± 1.01 Ti-30 Nb 30 wt % 29.09 ± 0.45 Ti-35 Nb 35 wt % 35.72 ± 0.68
[0020] X-ray diffraction (XRD) for phase analysis was conducted using a Rigaku diffractometer (Rigaku D-max IIIV, Rigaku Co., Tokyo, Japan) operated at 30 kV and 20 mA. A Ni-filtered CuK α radiation was used for this study. A silicon standard was used for calibration of diffraction angles. Scanning speed of 1°/min was used. The phases were identified by matching each characteristic peak in the diffraction pattern with the JCPDS files. The results are shown in FIG. 1, and are summarized in Table 2.
TABLE 2 Sample code Phase Crystal structure c.p. Ti α′ Hexagonal Ti-5 Nb α′ Hexagonal Ti-10 Nb α′ Hexagonal Ti-15 Nb α′/α″ Hexagonal/orthorhombic Ti-17.5 Nb α″ Orthorhombic Ti-20 Nb α″ Orthorhombic Ti-22.5 Nb α″ Orthorhombic Ti-25 Nb α″ Orthorhombic Ti-27.5 Nb α″/β Orthorhombic/bcc Ti-30 Nb α″/β Orthorhombic/bcc Ti-35 Nb β bcc
[0021] Three-point bending tests were performed using a desk-top mechanical tester (Shimadzu AGS-SOOD, Tokyo, Japan) operated at 0.5 mm/sec. Reduced size (36×5×1 mm) specimens were cut from the castings and polished using sand paper to a #1000 level. The bending strengths were determined using the equation,
σ=3 PL/ 2 bh 2
[0022] where σ is bending strength (MPa); P is load (Kg); L is span length (mm); b is specimen width (mm) and h is specimen thickness (mm). The modulus of elasticity in bending was calculated from the load increment and the corresponding deflection increment between the two points on a straight line as far apart as possible using the equation,
E=L 3 ΔP/ 4 bh 3 Δδ
[0023] where E is modulus of elasticity in bending (Pa); ΔP is load increment as measured from preload (N); and Δδ is deflection increment at midspan as measured from preload. The average bending strength and modulus of elasticity in bending were taken from at least six tests under each condition.
[0024] The comparison of the bending strength and modulus of the Ti—Nb alloys prepared in the present invention together with c.p. Ti are shown in FIGS. 2 and 3.
[0025] The microhardness of polished alloys was measured using a Matsuzawa MXT70 microhardness tester at 200 gm for 15 seconds. The results are shown in FIG. 4.
[0026] The inventors have gathered mechanical properties of several well known c.p. Ti and Ti alloys, which are listed in the following Table 3 together with those of the biocompatible binary Ti—Nb alloys of the present invention.
TABLE 3 Bending Hard- Bending mod- Ma- Strength/ Property ness strength ulus jor modulus Cast alloy (HV) (MPa) (GPa) phase ×1000 c.p. Ti (Grade 2) 156 884 92 α′ 9.6 c.p. Ti (Grade 4) 1315 110 α′ 11.9 Ti-15Mo 307 1348 71 β 19.0 Ti-6A1-4V 294 1857 105 α′ + β 17.7 Ti-13Nb-13Zr 285 1471 66 α′ + β 22.3 Ti-7Mo-7Hf 1299 67 β 19.4 Ti-35.3Nb-5.7Ta-7.3Zr 1133 63 β 18.0 Ti-15Nb 307 1565 61.8 α″ 25.3 Ti-20Nb 292 1466 60.4 α″ 24.3 Ti-25Nb 327 1656 77.1 α″ 21.5
[0027] It can be seen from Table 3 that the biocompatible binary Ti—Nb alloys of the present invention have a high bending strength and a low modulus (high strength/modulus ratios) compared to the prior art Ti alloys.
[0028] Table 4 lists the critical anodic current density (I corr ) of the c.p. Ti and selected Ti—Nb alloys of the present invention obtained from the potentiodynamic polarization profiles thereof in 37° C. Hanks' solution.
[0029] It can be seen from Table 4 that all the alloys have an excellent corrosion resistance.
TABLE 4 c.p. Ti Ti-5Nb Ti-17.5Nb Ti-27.5Nb Ti-35Nb I corr (μA/cm 2 ) 0.629 1.256 0.782 0.645 2.239
[0030] Although the present invention has been described with reference to specific details of certain embodiments thereof, it is not intended that such details should be regarded as limitations upon the scope of the invention except as and to the extent that they are included in the accompanying claims. Many modifications and variations are possible in light of the above disclosure. | A biocompatible binary titanium-niobium (Ti—Nb) alloy having a low modulus and a high strength, and containing α″ phase as a major phase is disclosed. The binary Ti—Nb alloy contains 10-30 wt % of Nb, preferably 13-28 wt % of Nb, and the balance titanium, which is suitable for making a medical implant such as an orthopedic implant or dental implant. | 8 |
This application is a continuation-in-part-application of application Ser. No. 07/789,291, filed Nov. 8, 1991 abandoned.
BACKGROUND OF THE INVENTION
The present invention relates to a method for the stabilization of a higher unsaturated organic compound having at least one double bond in a molecule such as those compounds used in the control of insect pests by the method of mating disruption as a sex pheromone of the insect or, more particularly, to a method for the stabilization of an ester, alcohol, ketone or hydrocarbon compound having at least 10 carbon atoms and at least one double bond in a molecule.
In relation to the pest control in agriculture by using agricultural chemicals, serious problems are noted in recent years including increased resistance against chemicals acquired by the insect species and the toxicity of the chemicals against the health of the agricultural workers as well as consumers of the agricultural products due to the residual amount of the chemicals in the products. As a countermeasure for these problems, biological methods for insect pest control are now under way of intensive investigations, of which the most promising is the method of mating disruption by utilizing various kinds of chemically synthesized sex pheromone compounds as a secretion of the insect females to attract males. It is very important in this method of pest control to keep a constant rate of release of the sex pheromone compound in the field over a long period of time, for example, by the use of the sustained-release dispensers disclosed in Japanese Patent Publication No. 61-16361. In this regard, difficulties are encountered in the use of the sex pheromone compounds for the insect pests belonging to the order of Lepidoptera which are each a long-chain aliphatic compound having at least 10 carbon atoms and at least one double bond in a molecule. The presence of double bonds in such a compound is responsible for the denaturation of the compound by the reaction of oxidation, isomerization, oligomerization and the like at the double bond when the sex pheromone compound is kept under outdoor conditions.
With an object to solve this problem, a method is proposed for the stabilization of a sex pheromone compound by the admixture thereof with an antioxidant or ultraviolet absorber. For example, it is reported in Journal of Chemical Ecology, volume 14, No. 8, page 1659 (1988) that the stability of a sex pheromone compound can be improved by the addition of an antioxidant such as di-tert-butyl hydroxytoluene or tert-butyl hydroxyanisole in combination with an ultraviolet absorber such as 2-hydroxy-4-methoxy benzo-phenone and the like. Further, Japanese Patent Publication 63-12452 teaches that the stability of a higher unsaturated aliphatic aldehyde compound can be increased by the combined admixture of a benzophenone compound as an ultraviolet absorber with an antioxidant and a tertiary amine compound.
Although it is indeed that combined use of a specific antioxidant and a specific ultraviolet absorber synergistically contributes more to the improvement of the stability of a sex pheromone compound having a double bond in the molecular structure than in the use of either one of them alone, no quite satisfactory stabilizing effect can be obtained with any combinations of heretofore known antioxidants and known ultraviolet absorbers. Accordingly, it is eagerly desired to obtain a high stabilizing effect on various sex pheromone compounds by the combined addition of stabilizing agents.
It is proposed in U.S. Pat. No. 4,568,771 that a higher aliphatic unsaturated aldehyde compound can be stabilized against oxidation by the admixture of a tertiary amine compound, benzophenone compound, salicylate compound, benzotriazole compound or cyanoacrylate compound together with or without further admixture of an antioxidant. When the sex pheromone compound is not an aldehyde but an ester, alcohol, ketone or hydrocarbon compound, no very effective method is known for the stabilization of such a compound.
SUMMARY OF THE INVENTION
The present invention accordingly has an object to provide a very efficient method for the stabilization of a sex pheromone compound which is a long-chain aliphatic ester, alcohol, ketone or hydrocarbon compound having at least 10 carbon atoms in a molecule and at least one double bond in the molecular structure by the admixture of compounds having a stabilizing and antioxidizing effects thereon in combination to exhibit a synergistic effect.
Thus, the method of the present invention for the stabilization of a compound belonging to one of the above named classes, which is a long-chain aliphatic compound having at least 10 carbon atoms in a molecule and at least one double bond in the molecular structure, comprises: admixing the compound with 2-(2′-hydroxy-5′-methyl-phenyl) benzotriazole and a phenolic compound as an antioxidant in combination each in an amount in the range from 0.1 to 10% by weight based on the amount of the compound to be stabilized.
It is preferable, in particular, that the above mentioned phenolic compound as an antioxidant is selected from the group consisting of tert-butyl hydroquinone, 2,5-di-tert-butyl hydroquinone and 2,5-di-tert-amyl hydroquinone.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The above described method of the invention for the stabilization of a higher aliphatic unsaturated compound, the scope of which consists in the combined admixture of a specific benzotriazole compound and an antioxidant or, in particular, a specific hydroquinone compound, has been established as a result of the extensive studies undertaken by the inventors with an object to discover a combination of stabilizing agents capable of synergistically stabilizing such an unsaturated compound even when it is not a long-chain aliphatic aldehyde compound having at least one double bond in a molecule, which is notoriously unstable to cause denaturation by the reaction of oxidation, isomerization and oligomerization at the double bond as well as the autoxidation reaction of the aldehyde resulting in the formation of a carboxylic acid or an oligomer. It has been unexpectedly discovered that the above described combination of the specific stabilizing agents has a strong stabilizing effect on the long-chain unsaturated aliphatic ester, alcohol, ketone and hydrocarbon compounds belonging to the classes of sex pheromone compounds having at least one double bond in a molecule. It is important that the specific benzotriazole compound and an antioxidant or, in particular, the specific hydroquinone compound are used in combination in order to exhibit a strong synergistic effect. If desired, other types of stabilizing agents can be used in combination with these two compounds.
The amounts of addition of these specific benzotriazole compound and antioxidant are each in the range from 0.1 to 10% by weight based on the amount of the higher aliphatic unsaturated compound. In particular, the amount of the benzotriazole compound is preferably in the range from 1 to 5% by weight based on the amount of the higher aliphatic unsaturated compound. When the amount of either one of the compounds is too small, the desired stabilizing effect cannot be fully exhibited as a matter of course while no further improvement can be obtained by increasing the amount thereof to exceed the above mentioned upper limit rather with an economical disadvantage.
Examples of the phenolic compounds as an antioxidant which can be used in combination with the specific benzotriazole compound include tert-butyl hydroquinone, 2,5-di-tert-butyl hydroquinone, 2,5-di-tert-amyl hydroquinone, 4-methoxy phenol, 2-tert-butyl-4-methoxy phenol, 3-tert-butyl-4-methoxy phenol, 2,6-di-tert-butyl-4-methoxy phenol, 2,6-di-tert-butyl-4-methyl phenol, 2,5-di-tert-butyl-3-hydroxy phenol, hydroquinone, 4,4′-methylene bis-(2,6-di-tert-butyl phenol) and the like, of which tert-butyl hydroquinone, 2,5-di-tert-butyl hydroquinone and 2,5-di-tert-amyl hydroquinone are particularly preferable in view of the high stabilizing effect on and good miscibility with the higher aliphatic unsaturated ester, alcohol, ketone or hydrocarbon compound.
The method of the present invention is applicable to any one of the ester, alcohol, ketone and hydrocarbon compounds provided that it is a long-chain aliphatic compound having at least one double bond in a molecule although the advantage obtained by the inventive method is remarkably high when the method is applied to a compound selected from the group consisting of: Z-7-dodecenyl acetate; Z-8-dodecenyl acetate; Z-9-dodecenyl acetate; E,Z-7,9-dodecadienyl acetate; E,E-8,10-dodecadienyl; E-4-tridecenyl acetate; Z-9-tetradecenyl acetate; Z-9-tetradecenol; Z-11-tetradecenyl acetate; Z,E-9,11-tetradecadienyl acetate; Z,E-9,12-tetradecadienyl acetate; Z-11-hexadecenyl acetate; Z,Z-7,11-hexadecadienyl acetate; E,E,Z-4,6,10-hexadecatrienyl acetate; Z,Z-3,13-octadecadienyl acetate; E,Z-3,13-octadecadienyl acetate; Z-13-icosen-10-one; E,E,Z-10,12,14-hexadecatrienyl acetate; E,Z,Z-4,7,10-tridecatrienyl acetate; E,Z-4,7-tridecadienyl acetate; Z,Z,Z-3,6,9-nonadecatriene; Z,Z,Z-3,6,9-eicosatriene; Z,Z,Z-3,6,9-heneicosatriene and the like. In particular, the advantage obtained by the inventive method is more remarkable when the compound to be stabilized is a long-chain aliphatic compound having two or more double bonds in a molecule such as long-chain aliphatic acetates and alcohols having a 1,3- or 1,4-dienic structure among the above named compounds.
In the following, the method of the present invention is illustrated in more detail by way of examples and comparative examples although the scope of the invention is never limited thereby in any way.
EXAMPLE
In each of the tests No. 1 to No. 20 described below, a glass capillary tube (test No. 1 to No. 5) or polyethylene capillary tube (test No. 6 to No. 20) having an inner diameter of 1 mm, outer diameter of 2 mm and length of 200 mm was filled with 100 mg of a liquid mixture of one of the higher aliphatic unsaturated compounds I to VII shown below as the test compound with 2-(2′-hydroxy-5′-methylphenyl) benzotriazole, referred to as HMBT herein-below, in an amount of 1 to 3% by weight indicated in Table 1 and one of the five phenolic compounds shown below in an amount indicated in Table 1 and kept standing outdoors as tightly stoppered to be kept outdoors and exposed to direct sun light during a period of three months starting with June in central Japan (test No. 1 to No. 5) or kept standing for three months under irradiation with a xenon lamp (test No. 6 to No. 20).
After the above mentioned three months exposure, the capillary tubes were opened and the liquid mixture taken out was subjected to the gas chromatographic analysis by the internal standard method to determine the percentage of the test compound remaining undecomposed in the respective mixtures. The results are shown in Table 1.
Higher Aliphatic Unsaturated Compounds (test compounds)
I: E,Z-7,9-dodecadienyl acetate
II: E,Z-9,11-tetradecadienyl acetate
III: E,Z-9,12-tetradecadienyl acetate
IV: Z,Z-7,11-hexadecadienyl acetate
V: E,E-8,10-dodecadienyl
VI: Z-13-icosen-10-one
VII: Z,Z,Z-3,6,9-eicosatriene
Phenolic Antioxidant Compounds
TBH: tert-butyl hydroquinone
DBH: di-tert-butyl hydroquinone
DAH: di-tert-amyl hydroquinone
BHT: di-tert-butyl hydroxytoluene
BHA: tert-butyl hydroxyanisole
TABLE 1
Test
Test com-
HMBT
Antioxidant added
Undecompos-
No.
pound
added, %
Compound
%
ed amount, %
1
I
2
TBH
2
93
2
I
2
BHA
2
87
3
III
3
TBH
5
91
4
IV
3
TBH
2
94
5
IV
3
BHT
2
91
6
I
1
DBH
1
75
7
I
1
DAH
5
73
8
I
1
BHT
2
71
9
II
2
DBH
2
73
10
II
2
TBH
2
68
11
II
2
DAH
1
70
12
II
2
BHT
5
69
13
III
2
DAH
2
75
14
III
2
TBH
2
71
15
III
2
DBH
10
83
16
IV
1
DBH
0.2
89
17
V
1
BHT
2
88
18
V
1
DBH
1
85
19
VI
1
TBH
1
91
20
VII
2
DBH
5
67
COMPARATIVE EXAMPLE
The experimental procedure in each of the comparative tests No. 21 to No. 3 was substantially the same as in the preceding tests by using a glass capillary tube under exposure to direct sun light (test No. 21 to 25) or by using a polyethylene capillary tube under irradiation with a xenon lamp (test No. 26 to No. 36) except that, in some of the tests, the stabilizing agents were entirely omitted, the HMBT was replaced with one of the substitute compounds 2-hydroxy-4-methoxy benzophenone, referred to as HMBP hereinbelow, and 2-hydroxy-4-octoxy benzophenone, referred to as HOBP hereinbelow, or the phenolic antioxidant compound was replaced with one of other antioxidant compounds identified below each in an amount indicated in Table 2. The results of the tests are shown in Table 2.
Non-phenolic Antioxidant Compounds
QL: quinoline
VE: tocopherol
VEN: tocopherol nicotinate
TABLE 2
HMBT or substitute
Test
Test com-
com-
Antioxidant added
Undecompos-
No.
pound
pound
% added
compound
%
ed amount, %
21
I
none
none
8
22
I
HMBP
5
BHA
5
52
23
III
none
BHA
5
54
24
IV
none
none
43
25
IV
HMBP
5
TBH
1
76
26
I
HOBP
2
VE
5
46
27
I
HOBP
2
QL
1
34
28
II
HOBP
2
VE
1
43
BHT
1
29
II
HMBP
2
QL
5
39
30
II
HMBT
2
QL
3
41
31
III
HMBP
2
QL
5
28
32
III
HOBP
2
VEN
5
33
33
III
HMBT
3
VE
5
36
34
III
HOBP
2
QL
3
40
DBH
1
35
V
HMBP
2
QL
5
21
36
VII
HOBP
2
VE
2
38
BHA
2 | An efficient method is proposed for the stabilization of a sex pheromone compound of insect pest, which is a long-chain aliphatic unsaturated ester, alcohol, ketone or hydrocarbon compound having at least ten carbon atoms and at least one double bond in a molecule, used in pest control. The method comprises admixing the compound with 2-(2′-hydroxy-5′-methylphenyl) benzotriazole and an antioxidant which is preferably a hydroquinone compound such as tert-butyl hydroquinone, 2,5-di-tert-butyl hydroquinone and 2,5-di-tert-amyl hydroquinone. | 2 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention is directed to a system which is capable of tracking or classifying objects over a wide range of conditions. In particular, the present invention is directed to a system which sends out an electromagnetic pulse and analyzes a return signal reflected from an object to obtain information about the object such as its distance, velocity, or form. In particular, the invention is directed to a system of the general nature described above in which a frequency agile synthesizer is used to provide rapid frequency shifts in a system in which measures are taken to maintain phase coherency.
2. Description of the Related Art
Generally, radar operates by radiating electromagnetic energy and detecting return signal from a reflecting object. See, Skolnick, Radar Handbook, (McGraw-Hill, Inc., 2d. Ed., 1990). The principles of radar have been applied from frequencies of a few megahertz to well beyond the optical region (laser radar). Millimeter-wave radar is generally understood to be radar operating in the frequency region of 40 to 300 GHz. One band in this region is the W band, which is nominally the frequency range of 75 GHz to 110 GHz. Radar systems generally include a transmitter, an antenna, a receiver, signal processing equipment, and data processing equipment.
One particular application for systems operating in the millimeter-wave region of the spectrum is in projectiles ("seekers") which generate a millimeter wave signal, send it toward a target, and analyze the return signal to generate directional information.
One problem that occurs when detecting targets by seeker systems is range ambiguity where a target appears to be at a much shorter range than it actually is. Range ambiguity occurs when the roundtrip transit time for the most distant target to be detected is longer than the interpulse period. More particularly, if a target is detected whose transit time exceeds the interpulse period, the echo of one pulse will be received after the next pulse has been transmitted so that the target is improperly detected to be at a range that is too close.
It is known to gauge the range ambiguities and the return from a single target by a number of interpulse periods spanned by the transit time. That is, the range ambiguities are gauged by whether the target's echoes are received during the first, second, third, etc. interpulse period following the transmission of the pulses that produce them. An echo received during the first interpulse period is called a single-time-around echo and echoes received during subsequent periods are called multiple-time-around echoes (MTAEs).
For a given PRF, the longest range from which single time around echoes can be received, and the longest range from which any return may be received without the observed ranges being ambiguous for that matter, is called the maximum unambiguous range or the unambiguous range. This unambiguous range is commonly represented by R u and because the roundtrip transit time for the unambiguous range equals the interpulse period
R.sub.u =cT/2
where c equals the speed of light and T equals the interpulse period,
T=f/1,
with
f=PRF
The possibility of range ambiguities may be eliminated by making the PRF low enough to place the unambiguous range beyond the maximum range at which any target is likely to be detected. However, because large targets may be detected at very great ranges, it may be impractical to set the PRF too low even when a comparatively low PRF might otherwise be acceptable. On the other hand, it may be that the probability of detecting large targets is slight for the expected conditions of use and the consequences of sometimes mistaking these targets for targets at closer range may be tolerable. If targets at greater ranges than the unambiguous range are of no concern, the range ambiguity problem may be solved by simply rejecting all returns from distances beyond the unambiguous range.
One technique of rejecting the returns is PRF jittering which takes advantage of the dependence of the apparent ranges of targets beyond the unambiguous range on the PRF. In this technique, however, the time-on-target is generally limited since it must be divided between the two PRFs which cuts the total potential integrated time in half and reduces the maximum detection range.
To resolve range ambiguities when the PRF must be made so high that the maximum range of interest is longer than the unambiguous range, various techniques may be employed.
SUMMARY OF THE INVENTION
The present invention is embodied as a high performance MMW system. In one aspect, the system is fully coherent because all of its transmitted signals derive from a common source. The system is also capable of high pulse repetition rates and can transmit duty cycles of 0 to 100%. The system is able to transmit complex phase and frequency modulated waveforms by using a frequency interleaving scheme at high PRF. It preferably uses a complementary phase coding scheme to allow high range resolution profile processing. The system resolves range ambiguity through the use of frequency interleaving. It varies the frequency of successively transmitted pulses, detects corresponding variations in the target echoes, and then uses the detected variation to match the echo to the transmitted pulse which created it.
In one aspect, the invention is an apparatus comprising a waveform generator for generating a waveform and a second output coherent with the waveform, the waveform generator including a frequency agile synthesizer capable of changing its output frequency at a high speed, the frequency and phase of the waveform and the second output being based on the output of the frequency synthesizer. An antenna coupled to the waveform generator transmits the waveform, receives a return signal, and generates at least one antenna output signal on the basis of the return signal. The system also includes a receiver coupled to the antenna and to the waveform generator, the receiver receiving the antenna output signal and the second output and converting the return signal on the basis of the second output signal to produce a converted signal. The system also has a processor for processing the converted signal to derive target data.
Preferably, the frequency agile synthesizer is capable of changing its output frequency in a psuedorandom manner, of changing its output pulse width, and of changing its pulse repetition frequency. It is also preferably capable of impressing an arbitrary phase code on each pulse transmitted in which case the processor will perform pulse compression on the basis of the phase code.
The waveform generator may include a millimeter wave phase locked oscillator connected to the frequency agile synthesizer for generating a millimeter wave oscillator output which is phase coherent with the frequency agile synthesizer output frequency, and a frequency upconverter connected to the frequency agile synthesizer and to the phase locked oscillator for generating an upconverted output signal which is a millimeter wave multiple of and phase coherent with the frequency agile synthesizer output. The waveform generator may further include a first frequency multiplier having the waveform as its output, a second frequency multiplier having the second output as its output, and a switch connected to the frequency upconverter for selectably connecting the upconverted output signal to the first frequency multiplier or the second frequency multiplier under control of the frequency agile synthesizer. The frequency agile synthesizer may control the switch to connect the upconverted output signal to the first frequency multiplier during a transmit operation and to connect the upconverted output signal to the second frequency multiplier during a receive operation.
The antenna may be a Cassegrainian dual-reflector antenna having a plurality of subassemblies for providing monopulse returns in both azimuth and elevation. The plurality of subassemblies may comprise a collimator, a circular polarizer and an amplitude monopulse feed.
The receiver may include at least one frequency downconverter connected to the antenna for converting the antenna output signal to a lower frequency signal, with the downconverter being connected to receive the second output and generating the lower frequency signal to be phase coherent with the second output. The receiver may also include at least one IF receiver connected to the frequency downconverter for converting the lower frequency signal to baseband in-phase and quadrature outputs.
The antenna may produce a first antenna output signal and a second antenna output signal. The receiver may then comprise a first frequency downconverter connected to the antenna for converting the first antenna output signal to a first lower frequency signal and a second frequency downconverter connected to the antenna for converting the second antenna output signal to a second first lower frequency signal as well as downconverter and the second frequency downconverter for converting the first and second lower frequency signals to baseband in-phase and quadrature outputs.
The processor processes the converted signal to derive target detection data and/or target tracking data. It may also send phase codes to transmit to the frequency agile synthesizer, such that the phase codes may be compressed when received by the processor.
In another aspect the invention comprises a method including the steps of generating a waveform and a second output coherent with the waveform by using a frequency agile synthesizer capable of changing its output frequency at a high speed, the frequency and phase of the waveform and the second output being based on the output frequency of the frequency synthesizer, transmitting the waveform, receiving a return signal, generating at least one antenna signal on the basis of the return signal, converting the return signal on the basis of the second output signal to produce a converted signal, and processing the converted signal to derive target data.
The frequency agile synthesizer may change its output frequency in a psuedorandom manner, change its output pulse width, change its pulse repetition frequency, or impress an arbitrary phase code on each pulse transmitted.
Waveform generation may be accomplished by upconverting the output of the frequency agile synthesizer to produce an upconverted output signal which is a millimeter wave multiple of and phase coherent with the frequency agile synthesizer output, and selectably connecting the upconverted output signal under control of the frequency agile synthesizer to a first frequency multiplier to produce the waveform or a second frequency multiplier to produce the second output.
The converting step may be carried out by converting the antenna output signal to a lower frequency signal which is phase coherent with the second output.
Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus, are not limitative of the present invention, wherein:
FIG. 1 is a functional block diagram for a millimeter wave system according to a first presently preferred embodiment of the present invention;
FIG. 2 is a more detailed functional block diagram of a possible implementation of the millimeter wave system of FIG. 1;
FIG. 3 is a functional block diagram of a waveform processor which may be incorporated into the present invention; and
FIG. 4 is a functional block diagram of a six port monopulse dual circular polarization antenna which may be incorporated into an embodiment of the present invention.
DETAILED DESCRIPTION
FIG. 1 is a functional block diagram of a first presently preferred embodiment of the present invention. The system of FIG. 1 includes a waveform generator 10 which is connected as shown with an antenna 20 and a receiver 30. It will be understood that functions of a transmitter and the receiver can be combined into one unit referred to as a transceiver. The antenna 20 is in turn connected to the receiver 30. The receiver 30 is connected to an IF receiver 40 which in turn is connected to a vector signal processor (VSP) 50. Here and elsewhere, to say that two or more elements are "connected" means signals can propagate between or among the elements, either directly or indirectly.
The waveform generator 10 generates the signal to drive the antenna. As will be described in more detail below, it includes a frequency agile synthesizer. The signal from the synthesizer is the basis for generating a pseudo-random frequency agile, high PRF waveform to be used for high range resolution processing and Doppler beam sharpening processing as well as for target recognition and target tracking. The pulse width, frequency, and PRF of the output waveform are each variable as desired. The waveform generator 10 also impresses an arbitrary phase code on each pulse transmitted.
The antenna 20 in this system may be a known antenna such as a Cassegrainian reflector, a horn, a dual polarization monopulse antenna having multiple receive channels, or another type of antenna. The antenna 20 receives the waveform from the waveform generator 10, transmits it, and receives return signals that have reflected off an object.
As will be explained more completely below, the receiver 30 receives the signals from the antenna 20, conditions them, and relays them to the IF receiver 40. The IF receiver 40 receives the controlled signals transmitted by the waveform generator 10 through the receiver 30 at a predetermined intermediate frequency. The VSP 50 receives the output of the IF receiver 40 and interprets a received pulse repetition frequency, pulse compressed waveform based on the signals output from the IF receiver 40 within the predetermined intermediate frequency for reporting target information.
The received pulse repetition frequency, pulse compressed waveform may be a high PRF in an embodiment of the present invention, but the system also operates at low and medium PRF in other embodiments as well. The high PRF provides a higher average power than the low and medium PRFs. The VSP 50 interprets the received PRF, pulse compressed waveform from the IF receiver 40 within the predetermined frequency and reports target information. The target information includes target size, range and tracking information calculated based on a target analysis using known algorithms such as constant false alarm rate (CFAR), for example.
FIG. 2 is a more a detailed circuit diagram of a system such as that shown in FIG. 1. FIG. 2 illustrates a W-band seeker. The waveform generator 10 for the W-band seeker for this embodiment includes a frequency agile synthesizer 100. The output of the frequency agile synthesizer 100 is connected to a Ka-band upconverter 110 and a Ka-band phase locked oscillator OSC 120. The OSC 120 is connected to the Ka-band upconverter 110 which is phase locked to the reference of the frequency agile synthesizer 100. The Ka-band upconverter 110 upconverts the output of the frequency agile synthesizer 100 based on the output from the OSC120 to a similar millimeter wave frequency. The Ka-band upconverter 110 includes a bandpass filter. The output of the Ka-band upconverter 110 is connected to an isolation/power amplifiers 130 and 140 to drive downstream frequency multipliers as will be described. The amplifiers 130 and 140 must operate in a manner which preserves the phase code of the generated waveform.
In the embodiment illustrated in FIG. 2, the output of the power amplifier 140 is connected to a transmit/receive (T/R) switch 150. The T/R switch 150 directs the amplified upconverter output either to a first frequency multiplier 160 or a second frequency multiplier 170 in response to an output of the frequency agile synthesizer 100. Either first frequency multiplier 160 or second frequency multiplier 170 multiplies the millimeter wave frequency to a higher frequency by the selected frequency multiplier as desired. For example, the frequency may be trebled. When the frequency multiplier 170 is selected, the output is sent to an amplifier 180 and then to a polarization switch 190. The switch 190 sends the amplified output of the second frequency multiplier 170 to either a first duplexer 200 or a second duplexer 210 in response to an output of the frequency agile synthesizer 100.
The signal from the duplexers 200 and 210 is then coupled to the antenna 20. The antenna 20 in this example may be a dual circularly polarized monopulse antenna. As a result of the coupled energy, the antenna 20 radiates a signal and then receives a return pulse.
The power requirements for the amplifier 180 are determined with reference to what is needed for a high PRF, pulse compressed, low peak power waveform. A travelling wave tube or other power amplifying device can be used as the amplifier 180 if necessary.
The waveforms are also subjected to pulse compression which involves sending a long transmit pulse with a special phase code. See, Skolnick, Radar Handbook, Section 10.6 (McGraw-Hill, Inc., 2d. Ed., 1990). Each pulse is divided into a number of subpulses of equal duration. Each subpulse has a particular phase selected in accordance with a predetermined code sequence. With biphase coding, the binary code is a sequence of two values (usually 0s and 1s or +1s and -1s). The phase of the transmitted signal alternates between 0° and 180° in accordance with the sequence of elements. It is preferable to use the special class of binary codes known as "Barker" codes. These codes have the property of exhibiting minimum side lobes when compressed.
After the coded pulse is sent and the return signal received and conditioned, the pulse is compressed. Pulse compression may comprise an acoustic delay line compressor located in the IF receiver section or a digital algorithm implemented in the signal processor. For example, the pulse may be compressed by generating a sequence of delayed signals delayed with respect to one another by a delay equal to one to one phase code pulse length. The delayed signals are then summed with either a +1 or -1 weighting. The result of this summing is close to zero except when the target lines up with the delay line in which case the result increases to N times the signal return. Therefore, a long low power pulse looks like a short, high powered pulse.
AB-BA coding is a refinement of pulse compression. When a pulse is compressed, time side lobes may be generated. Time side lobes look like targets and are undesirable. To suppress time side lobes, two separate codes (an A code and a B code) are sent first in one order (say, AB) and then the other (BA). The returns can then averaged to suppress time side lobes. In digital pulse compression using complementary phase code pairs designated A and B, the A and B coded pulses are generated at a given frequency on successive pulses or on successive ramps as required to ensure unambiguous range operation for the range/pulse repetition frequency combination. Following pulse compression processing on individual pulses, the resultant A and B coded data for a given frequency are summed to reduce the time side lobes. In the resent embodiment, a processor 600 described below sends the phase codes to the frequency agile synthesizer, which then uses the phase codes as the basis for its synthesis.
Furthermore, a frequency hopping pattern may be implemented such that the second and third time around returns from non-targets at long distances are excluded from signal processing by placement of these returns outside the instantaneous passband of the receiver. If at time t n , a frequency f n is transmitted, then for frequencies f n+1 and f n+2 transmitted at times t n+1 and t n+2 , respectively, the absolute value of f n -f n+1 and f n -f n+2 must be greater than twice the transmitted pulse bandwidth to ensure passband rejection of f n+1 and f n+2 when f n is being received. This must be true for all frequencies in a given processing interval (dwell).
As mentioned, the antenna 20 for the present embodiment may be a Cassegrainian dual-reflector antenna having collimator, circular polarizer and amplitude monopulse feed subassemblies. This is a known antenna for seeker applications. The Cassegrainian antenna has a network of hybrids which produce for each polarization a sum channel signal which is proportional to the power received and a difference channel signal which is zero when the target is exactly on axis and varies positively and negatively as the target moves to one side or another.
The combination of these signals is used to derive tracking information. The sum channel signals are connected to the duplexers 200 and 210, respectively, and the outputs of the duplexers 200 and 210 along with the difference channel signals are respectively connected to low noise amplifiers 300, 310, 320, and 330. The outputs of the low noise amplifiers 300, 310, 320, and 330 are respectively connected to downconverters 340, 350, 360, and 370. A local oscillator frequency for the downconverters originates from the first frequency multiplier 160 when selected by switch 150. The local oscillator frequency reaches the downconverters through a local oscillator distribution circuit LOD 380.
The downconverters 340 and 350 are connected to an IF receiver 400 and the down converters 360 and 370 are connected to an IF receiver 410 in the IF receiver section 40. Both IF receivers allow the four receiver channels to be multiplexed into two channels, reducing the number of analog to digital conversions needed. The IF receivers convert the received signal to baseband in-phase and quadrature outputs. The outputs of the IF receivers 400 and 410 are connected to high speed A/D converters 420 and 430, respectively. The A/D converters have a clock which is synchronous with all other system frequencies. The outputs of the A/D converters 420 and 430 are output to first and second vector signal processors (VSPs) 500 and 510 in VSP section 50 for performing pulse compression as described and target detection.
The VSPs 500 and 510 are connected to a digital processor 600 which receives the high PRF/high duty cycle waveform incorporating digital pulse compression and digital I/Q generation. FIG. 3 illustrates a waveform processor 600 for receiving and processing the high PRF, frequency stepped waveform. The waveform processor 600 includes a plurality of 32-Point FFTs 610 1 , 610 2 , . . . 610 32 and 620 1 , 620 2 , . . . 620 32 and a plurality of summing circuits 630 1 , 630 2 , . . . 630 32 and 640 1 , 640 2 , . . . 640 32 for processing a waveform. The waveform processor 600 operates by stepping 32 times within a ramp. The step size may be 265 kHz. A template may include, for example, 32 ramps, and a dwell may consist of five templates. The 32 ramp inputs and 32 frequency inputs are respectively processed by the FFTs 610 and 620 and then summed in the summing circuits 630 and 640. The summed ramp signals are processed and stored in a high range resolution (HRR) memory 650. The process is repeated for each range bin and receiver channel. At the same time, the 32 frequency signals are processed and stored in a Doppler beam sharpening (DBS) processor 660 and is also repeated for each range bin and receiver channel.
A single frequency radar with a single PRF cannot unambiguously resolve the range to targets if the range is farther away than
2PRF/c
due to the returned pulse from the "second time around" from the target. In the present system, however, the high speed of the frequency agile synthesizer 100 allows frequency changes for each pulse. The system transmits a series of frequencies having a psuedo-random pattern and "listens for" only the n-1, n-2, or n-3 frequencies. The system also does not repeat a frequency until all frequencies in a predetermined set of frequencies (a template, which is 32 ramps in the embodiment under consideration) have been used. Accordingly, only targets in a "correct" range appear at the receiver output. As a side benefit, since the transmitted signals are spread out instead of being in a continuous sequence, it is harder for a hostile listener to detect them.
The method of frequency interleaving for resolving range ambiguity performed as described above requires a rough estimate of the target range. Such a rough estimate is generally available, however, when searching for a target, in contrast to tracking a target. This estimated range is at the maximum detectable range for the target being searched for. Frequencies are then sent that increase or at least change from pulse-to-pulse so that pulses occur at a rate faster than they can return for a target at a maximum range.
For example, if the ambiguous range is 300 feet, a target at a range of 3000 feet can be detected by the present system. The local oscillator signal, that comes from the same synthesizer as the transmit signal, bounces between transmit and receive. Therefore, the detection of a target would not be expected until 10 pulses are transmitted (3000 feet divided by 300 feet) and a frequency pattern of f 1 , f 2 , f 3 , . . . f 10 has been sent. After the frequency f 10 is sent, the local oscillator switches to the appropriate frequency to receive f 1 , then a switch is made to transmit a frequency f 11 , next the appropriate frequency is switched for receiving f 2 , and then switching to transmit frequency f 12 and so on. This interleaving of frequencies continues according to this pattern. If the local oscillator frequency is not correct for a given transmit frequency, the frequency falls outside of the system bandwidth and is not detected. Thus, by interleaving frequencies, the range ambiguity is resolved and after a target is detected, the transmit/receive pattern can be continuously changed as well as the PRF if necessary, to keep the target in the desired range gate.
In general, targets far beyond the ambiguous range may be detected by transmitting a series of frequencies and then waiting long enough for the target to return to switch to the appropriate local oscillator frequency. The frequency transmission pattern must be selected such that the frequencies f 1 , f 2 , f 3 , . . . are not immediately adjacent and successive frequencies must be far enough apart so that they do not get through the receiver passband.
In one example of the present system there are 16 MHz frequency steps and a pulse width of 32 nanoseconds. Therefore, the IF filter must be 32 MHz wide (1/32 nanoseconds). If a given frequency is sent and then moved 16 MHz to transmit the next frequency, the second pulse return is within the 32 MHz passband of the receiver and will be improperly detected as a target. The second transmitted frequency must be 5 or 10 steps away to prevent this by having the return be well outside the receiver passband.
In one embodiment, the frequency agile synthesizer 100 used for transmitting and the offset signal used for receiving may include a four tone generator which feeds mix and divide circuitry in one embodiment. Programmable PRFs up to 500 kHz can be implemented. Offset local oscillator generation circuitry allows a received pulse to be sandwiched between subsequent transmit pulses of different frequencies which is required for unambiguous range operation. The ramp time and not the pulse repetition interval (PRI) determines the ambiguous range because pulses are "tagged" through frequency stepping. The resulting high PRF waveform increases the average power and provides a fixed detection range, reduces the peak transmitter power for a fixed detection range and increases the detection range for a fixed transmitter power if the radar is not clutter-limited. Programmability of the frequency agile synthesizer 100 enhances the applicability to multiple systems so that low and medium PRFs can be implemented with associated increases in the PC ratios to yield the required average power. Also, the inherent pseudo-random hopping capability improves electronic counter-countermeasures.
A low peak power transmitter approach significantly reduces cost relative to a high peak power unit by simplifying modulator circuitry, eliminating high voltage power supply and increasing reliability. Phase coding within a long pulse allows digital pulse compression, which yields an equal or greater average power than a short pulse, high peak power transmitter scheme. The low noise amplifiers 300, 310, 320, and 330 reduce system noise by 2 to 4 dB over comparable mixer implementations. For the same performance, the transmitter power output requirement is reduced and for the same transmitter output power, the operational range of the seekers are increased.
The antenna 20 which is a dual circularly polarized antenna for the embodiment illustrated in FIG. 2 allows true monopulse operation. FIG. 4 illustrates a six port monopulse design for use in a system according to the invention. In FIG. 4, the outputs of feed horns 701, 702, 703, and 704 are input to orthomode transducers 711, 712, 713, and 714. The outputs of the orthomode transducers 711 and 712 are sent to a hybrid circuit 721, the output from the orthomode transducer 711 is sent to a hybrid circuit 722 and the output from the orthomode transducer 712 is sent to a hybrid circuit 723. Similarly, the outputs from orthomode transducers 713 and 714 are sent to a hybrid circuit 724, the output of orthomode transducer 713 is sent to the hybrid circuit 723 and the output of the orthomode transducer 714 is sent to the hybrid circuit 722. The outputs of hybrid circuits 721 and 724 are sent to the hybrid circuits 731 and 732. Also, the outputs of hybrid circuits 722 and 723 are sent to hybrid circuits 733 and 734. As a result of this processing, the hybrid circuit 733 outputs a sum signal for lefthand circular polarization and a difference signal for the lefthand circular polarization of the azimuth, the hybrid circuit 734 outputs a difference signal for lefthand circular polarization of the elevation, the hybrid circuit 731 outputs a sum signal for righthand circular polarization and a difference signal for righthand circular polarization of elevation and the hybrid circuit 732 outputs a difference signal for righthand circular polarization of the azimuth.
To achieve the output levels necessary for all weather seeker range performance, improved power combining techniques have been used in the system for the embodiments of the present invention. A low peak power, long pulse transmit waveform eliminates requirements for complex high peak power, short pulse transmitters. The present seeker system cuts the power requirement in half. Accordingly, the present invention provides a seeker having several MMIC circuits wherein the seeker is 1) fully coherent, 2) capable of high pulse rate repetition rates (in excess of 1 MHz), 3) has no transmit duty cycle restrictions, 4) can transmit complex phase and frequency modulated waveforms, 5) can resolve range ambiguities by a frequency interleaving scheme at high PRD and 6) has a complementary phase coding scheme to allow high range resolution profile processing with the above waveforms.
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. | A radar system in which a frequency agile synthesizer is used to provide rapid frequency shifts and in which measures are taken to maintain phase coherency. The system is fully coherent such that all signals are derived from a common source and are capable of high pulse repetition rates in excess of 1 MHz. There are no inherent transmit duty cycle restrictions and the system is able to transmit complex phase and frequency modulated waveforms. A frequency interleaving scheme is used to resolve range ambiguities at high pulse repetition frequencies and the use of a complementary phase coding scheme allows a high range resolution processing with the transmitted waveforms. | 6 |
[0001] The invention relates to a method of using composite material to fabricate a mechanical member such as a rod for an aircraft landing gear strut.
BACKGROUND OF THE INVENTION
[0002] It is known, in particular from patent document FR 2 932 409, to fabricate such a rod by using a mandrel on which one or more layers of carbon fibers are braided in radial superposition on one another.
[0003] That assembly is then installed in a mold in order to inject resin into the various layers carried by the mandrel prior to polymerizing the resin, e.g. by heating it, thereby constituting a rigid blank for a rod, which blank can be machined at its interfaces in order to form lugs therein.
[0004] The braiding of the layers of reinforcing fibers is then performed with a braiding installation as shown in FIG. 1 , where it is referenced 1 . The installation essentially comprises a ring 2 extending in a vertical plane, with the central axis AX of the ring thus being horizontal. The ring 2 carries a set of reels 3 carrying reinforcing fibers, the fibers converging on a region that is situated on the axis AX and that is offset from the plane of the ring.
[0005] When the braiding cycle is started, the mandrel, referenced 4 , is moved along the central axis AX so as to pass through the ring 2 beyond the point where the fibers converge. Simultaneously, the reels carried on the ring 2 by motor-driven movable supports are actuated so as to reel out fibers in order to fabricate a sock of reinforcing fibers on the outside face of the mandrel 4 .
[0006] Once the mandrel has passed right through the ring, i.e. once it is situated beyond the fiber convergence point, it is covered over its entire length by the sock.
[0007] The layer of reinforcing fibers is then cut between the mandrel and the ring, and the mandrel is removed and then put back behind the ring in order to pass through it once more so as to form a second layer of reinforcing fibers that is superposed radially on the first.
[0008] Thus, as shown diagrammatically in FIG. 2 , it is possible to fabricate a general structure comprising the mandrel in its central region, which mandrel forms a support for two or more layers of braided fibers 6 , 7 that extend all around the mandrel, over its entire length.
[0009] Specifically, as shown in FIG. 3 , a braided layer comprises firstly interlacing fibers 8 and 9 that are inclined, e.g. at about 30°, on either side of the axis AX, and secondly longitudinal fibers 10 that are parallel to the axis AX, and that are held in position by the interlacing fibers 8 and 9 that interlace them.
[0010] In practice, and as can be seen in FIG. 3 , each layer of braided fibers is made up of a plurality of sublayers, levels, or thickness, each comprising a series of longitudinal fibers 10 situated beside one another in a comb arrangement. The interlacing fibers 8 , 9 interlace the longitudinal fibers 10 of the various sublayers together so as to form a coherent whole.
[0011] When the layers of braided fibers have been applied on the mandrel, the longitudinal fibers 10 of each sublayer are distributed uniformly about the mandrel 4 that carries them, i.e. they are regularly spaced apart from one another around the mandrel 4 , as shown diagrammatically in FIG. 4 .
[0012] In service, such a mechanical member is subjected to mechanical loading circumstances that are relatively complex, and as a result it is subjected to stresses that differ from one region of the member to another.
[0013] With a member fabricated by braiding, that situation leads to selecting the thickness of reinforcing fibers for depositing over the entire mandrel as a function of the maximum stress to which the member is to be subjected, even though the maximum stress actually corresponds only to a particular region of the member under consideration.
[0014] It follows that in many of its zones, the member is thus overdimensioned, thereby pointlessly penalizing the total weight of the member.
OBJECT OF THE INVENTION
[0015] The object of the invention is to propose a solution for remedying that drawback.
SUMMARY OF THE INVENTION
[0016] To this end, the invention provides a method of fabricating a mechanical member made of composite material, the method comprising a plurality of operations of braiding and depositing layers of braided reinforcing fibers by means of a braiding machine, each operation comprising braiding a layer of reinforcing fibers and depositing it on a mandrel by moving the mandrel along a central axis of the braiding machine, the various layers of braided fibers being superposed radially on one another, each layer of braided fibers having both longitudinal fibers extending parallel to a main direction of the mandrel, and also interlacing fibers that are inclined relative to the main direction, the method being characterized in that at least one braiding and deposition operation is configured to form and deposit a braid that presents, in at least one cross-section of the member, a density of longitudinal fibers that differs depending on whether consideration is given to a first angular region around the center of gravity of the mandrel in said cross-section or to a second angular region of the same extent around the center of gravity.
[0017] With this solution, the mechanical member presents greater thickness in an entire portion that extends over its entire length, and smaller thickness in the opposite portion.
[0018] The invention also provides a method as defined above, including at least one operation of braiding and depositing a layer of braided fibers that is performed to constitute a layer of braided fibers having longitudinal fibers of different sizes, and including longitudinal fibers of large size situated in a first region of the braided layer and longitudinal fibers of small size situated in a second region of the braided fiber.
[0019] The invention also provides a method as defined above, wherein a braiding machine is used having a braiding ring carrying reels of longitudinal fibers arranged in such a manner that each layer of braided fibers is made up of a plurality of superposed sublayers, each including a series of longitudinal fibers in a comb arrangement, wherein one region of the ring is loaded with reels of large-size longitudinal fibers and another region of the ring is loaded with reels of small-size longitudinal fibers, and wherein the proportion of reels carrying large-size fibers and of reels carrying small-size fibers varies gradually from one region of the ring to another.
[0020] The invention also provides a method as defined above, including at least one operation of braiding and depositing a layer of braided fibers, wherein the mandrel is positioned to have its main axis radially offset relative to the central axis of the braiding machine while the mandrel is being moved along the central axis of the braiding machine, so as to braid and deposit a layer of braided fibers presenting a quantity of longitudinal fibers that is greater in a first region that is closer to the central axis of the braiding machine than in a second region that is farther from the central axis of the braiding machine.
[0021] The invention also provides a method as defined above, wherein the provision of longitudinal fibers having different sizes is combined with a radial offset of the main axis of the mandrel relative to the central axis of the braiding machine.
BRIEF DESCRIPTION OF THE FIGURES
[0022] FIG. 1 is a diagrammatic perspective view of a braiding machine with a mandrel that is to receive a layer of braided fibers;
[0023] FIG. 2 is a diagrammatic cross-section view showing the layers making up a prior art rod of composite material;
[0024] FIG. 3 is a diagrammatic perspective view showing a portion of braided reinforcing fibers made up of two sublayers;
[0025] FIG. 4 is a diagrammatic cross-section view showing the longitudinal fibers of a sublayer forming part of a braided layer in a prior art rod;
[0026] FIG. 5 is a diagrammatic cross-section view showing the longitudinal fibers in a sublayer of a braided layer in a rod obtained in accordance with a first implementation of the invention;
[0027] FIG. 6 is a diagrammatic cross-section view showing the longitudinal fibers in a sublayer of a braided layer in a rod obtained in accordance with a second implementation of the invention;
[0028] FIG. 7 is a diagrammatic view of a portion of a ring of a braiding machine arranged to form a braid having longitudinal fibers of different sizes in accordance with the first implementation of the invention;
[0029] FIG. 8A is a diagrammatic side view showing an axial offset performed in the braiding operation in accordance with the second implementation of the invention;
[0030] FIG. 8B is a diagrammatic view in a cross-section plane of the FIG. 8A rod showing the mandrel together with the longitudinal fibers of one of the sublayers of the various braided layers carried by the mandrel;
[0031] FIG. 9 is a perspective view of a first example of a rod suitable for being fabricated in accordance with the method of the invention;
[0032] FIG. 10A is a diagrammatic side view showing an axial offset performed in the braiding operation in accordance with the second implementation of the invention in order to fabricate a rod including an off-center intermediate lug;
[0033] FIG. 10B is a diagrammatic view in a first cross-section plane of the FIG. 10A rod showing its mandrel and the longitudinal fibers of one of the sublayers of the braided layers carried by the mandrel;
[0034] FIG. 10C is a diagrammatic view in a second cross-section plane of the FIG. 10A rod showing its mandrel and the longitudinal fibers of one of the sublayers of the various braided layers carried by the mandrel;
[0035] FIG. 11A is a perspective view of a rod having an eccentric intermediate lug that may advantageously be fabricated in accordance with the method of the invention;
[0036] FIG. 11B is a first cross-section view of the FIG. 1A rod; and
[0037] FIG. 11C is a second cross-section view of the FIG. 11A rod.
DETAILED DESCRIPTION OF THE INVENTION
[0038] The idea on which the invention is based is to form and deposit on a mandrel layers of reinforcing fibers that are braided in such a manner that the longitudinal fibers of the layers present density that is greater on one side of the mandrel than on the other.
[0039] This may be achieved by providing longitudinal fibers in one region that are of greater size than the longitudinal fibers in another region of the braided layer, where this corresponds to a first implementation as shown in FIG. 5 . This may also be achieved by using longitudinal fibers that are all of the same size, but by placing them in greater quantity in one region than in another region of the layer of reinforcing fibers, with this corresponding to a second implementation shown in FIG. 6 .
[0040] In order to illustrate the density difference, FIGS. 5 and 6 thus show two angular regions or sectors S 1 and S 2 having the same angular extent, both centered on the center of gravity G of a cross-section of the mandrel 11 of the fabricated member, and arranged in such a manner as to be opposite each other. The region S 1 is situated in the top portion of the member while the region S 2 is situated in the bottom portion of the member.
[0041] In the configuration of FIG. 5 , each of the regions S 1 and S 2 has three longitudinal fibers, however the longitudinal fibers 12 G included in the top region S 1 are each of greater section than the longitudinal fibers 12 included in the bottom region S 2 . Thus, the density of longitudinal fibers is significantly greater in the top region than in the bottom region because the fibers in the top region are of section that is greater than the section of the fibers in the bottom region.
[0042] In the configuration of FIG. 6 , the longitudinal fibers 12 are all of the same size, i.e. of the same section, but the top region S 1 has five of them, whereas the bottom region S 2 has only three. In this configuration also, the density of longitudinal fibers is greater in the sector S 1 than in the sector S 2 , because the number of fibers in the top region is greater than the number of fibers in the bottom region.
[0043] In the first implementation of the invention, the reels of the large-size longitudinal fibers 12 G are placed in the top portion of the ring 13 of the braiding machine shown in part in FIG. 7 , and the reels of the smaller-size longitudinal fibers 12 are placed in the remainder of the ring.
[0044] In FIG. 7 , the reels of the large-size longitudinal fibers 12 G are represented by squares, whereas the reels of the smaller-size longitudinal fibers 12 are represented by triangles.
[0045] As mentioned above, each layer of braided fibers is made up of a plurality of thicknesses or sub-thicknesses, each including a series of longitudinal fibers in a comb arrangement, i.e. arranged side by side. In the example of FIG. 7 , the ring 13 includes, for this purpose, five concentric annuluses of reinforcing fiber reels that are spaced apart radially from one another relative to the central axis AX so as to form a layer of braided fibers that is made up of five sublayers.
[0046] In order to avoid having too great a change of thickness in the transition region between the fine longitudinal fibers 12 and the thick longitudinal fibers 12 G, it is advantageous to provide a particular distribution of the various reels on the ring of the braiding machine.
[0047] Specifically, and as shown in FIG. 7 , the reels are arranged on the annulus 13 in radial columns, each having five reels. A transition zone is provided that is situated in the angular sector referenced T in FIG. 7 , which sector lies between the bottom region of the ring 13 in which each of the radial columns has five reels of small-size longitudinal fibers and the top region of the ring in which each of the radial columns has five reels of large-size reinforcing fibers.
[0048] In this transition zone T there are four radial columns of reels referenced 16 to 19 . The first radial column 16 of reels has one reel of large-section longitudinal fibers followed by four reels of small-section fibers, this first column being adjacent to a column of the bottom portion, i.e. a column having only reels of small-size fibers.
[0049] The second column 17 , adjacent to the first, has two reels of large-section longitudinal fibers followed by three reels of small-section longitudinal fibers. The third column 18 , adjacent to the second, has three reels of large-section fibers followed by two reels of small-section fibers.
[0050] The fourth column 19 , adjacent to the third has four reels of large-section fibers and only one reel of small-section fibers, and this fourth column is adjacent to a column of the top region of the ring, i.e. a column having five reels of large-size fibers.
[0051] This transition zone T ensures that the increase in the thickness of the layer of braided reinforcing fibers is gradual instead of being sudden, which contributes to obtaining a uniform level of tension during braiding for all of the fibers in the braided layer.
[0052] It will thus be understood that fabricating a mechanical member in accordance with the first implementation consists in equipping the braiding machine with longitudinal fibers of large size and with longitudinal fibers of small size, as described above with reference to FIG. 7 .
[0053] A mandrel is then installed on the central axis AX of the braiding machine, the mandrel being arranged concentrically on this axis. The mandrel is then moved along the central axis while simultaneously the braiding machine is activated to form the braid of reinforcing fibers in a convergence zone of the fibers that is situated substantially on the central axis AX while being spaced apart from the ring 13 . The main function of the mandrel 11 is to support the various braided layers, or “preforms”, and to define the inside shape of the part.
[0054] Once the mandrel has passed through the reinforcing fiber convergence zone, it carries a layer of braided fibers. The layer may then be cut between the mandrel and the ring, prior to reinstalling the mandrel at the entrance to the ring 13 on the axis AX so as to move it once more along the axis in order to form and deposit a new layer of reinforcing fibers on the first braided layer.
[0055] Analogous steps are performed to form a predetermined number of reinforcing fiber layers that are radially superposed on one another on the mandrel, which is typically a generally tubular hollow part.
[0056] Once all of these layers have been deposited, the resulting element presents a thickness in its top region that is significantly greater than the thickness that it presents in its bottom region, with the difference in thickness corresponding to a difference in longitudinal fiber density.
[0057] The assembly is then placed in a mold in order to inject resin into the various deposited layers, prior to triggering a heating cycle for polymerizing the resin. The blank that is obtained at this stage is subsequently machined to form a finished part.
[0058] In the second implementation of the invention, the increase in the density of longitudinal fibers in the top region of each layer of braided fibers is obtained by offsetting the mandrel 11 radially relative to the central axis AX of the braiding machine along which the mandrel is moved in order to form and deposit the layers of braided fibers.
[0059] As shown diagrammatically in FIGS. 8A and 8B , the main axis AP of the mandrel is thus offset downwards relative to the central axis AX of the braiding machine, by an offset value written e.
[0060] In general manner, the main axis AP of the mandrel 11 corresponds to the axis defined by the centers of gravity of two cross-sections of the mandrel situated in a portion of the mandrel that corresponds to the body of the fabricated member, i.e. to a regular portion of the mandrel, such as its tubular portion.
[0061] Forming and depositing a layer of reinforcing fibers in accordance with this second implementation of the invention thus consists in moving the mandrel along the axis AX of the braiding machine while keeping it offset downwards relative to said axis AX.
[0062] Under such conditions, when the mandrel 11 reaches the fiber convergence zone, it is offset downwards relative thereto so that the braid that is formed progressively as the mandrel 11 advances through this convergence zone has a larger quantity of longitudinal fibers in its top region than in its bottom region, as shown diagrammatically in FIG. 8B .
[0063] Once the mandrel has passed right through the convergence zone, the fiber braid is cut between the mandrel and the ring. The mandrel is then returned to the entrance of the ring so as to form and deposit a new layer of reinforcing fibers.
[0064] As in the first implementation, once the predefined number of braided fiber layers has been deposited on the mandrel, the assembly is placed in a mold for resin to be injected and polymerized, prior to being machined in order to form a finished part.
[0065] In both its first and second implementations, the invention makes it possible to fabricate simple rods such as the rod 21 of FIG. 9 comprising a generally tubular main body and presenting ends, each provided with at least one lug.
[0066] However the invention is also applicable to fabricating mechanical members of more complex shape, such as for example the rod 22 shown in FIG. 11 , having a central body that is generally tubular with a lug at each end, but also having an intermediate lug. This intermediate lug is referenced 23 and is situated between its ends, and it extends radially relative to the main axis AP of the rod.
[0067] The rod 22 may be fabricated in accordance with the second implementation of the invention, i.e. by fitting the braiding machine with longitudinal fibers, all having the same size, but with the mandrel 11 being offset away from the central axis AX of the braiding machine.
[0068] In practice, the mandrel 11 is then positioned to offset its main axis AP relative to the axis AX so as to bring the intermediate lug 23 closer to the central axis AX, as shown in FIG. 10A .
[0069] Thereafter, the mandrel 11 is moved through the braiding machine along the axis AX while conserving this offset e so as to form and deposit thereon a braid of reinforcing fibers.
[0070] Once the mandrel has gone past the reinforcing fiber convergence point, the fibers are cut between the mandrel and the ring of the braiding machine. The mandrel is then returned to the entrance of the braiding machine, still with the radial offset e, and it is then moved along the axis AX in order to form and deposit another layer of reinforcing fibers.
[0071] Thus, and as shown diagrammatically in FIG. 10B , in an ordinary cross-section of the rod, i.e. in a portion of its main body that is tubular in shape, the quantity of reinforcing fibers is greater in the top portion than in the bottom portion.
[0072] In the region corresponding to the intermediate lug 23 , shown in cross-section in FIG. 10C , the reinforcing fibers are distributed uniformly over this lug and they are present in sufficient quantity to confer appropriate mechanical strength on the lug, even though it constitutes a projection extending radially from the body of the rod.
[0073] The value e of the offset may thus be adjusted so that the quantity of longitudinal fibers in the top portion is greater than in the bottom portion in the ordinary section of the rod and also in the intermediate lug 23 .
[0074] This adjustment corresponds to a rod of the kind shown in FIG. 11A , which presents a greater thickness of fibers in its top region in its ordinary section as shown in FIG. 11B and also in its section through the intermediate lug 23 , as shown in FIG. 11C .
[0075] In analogous manner, the rod 23 of FIG. 11 may also be fabricated using the first implementation of the invention, i.e. by fitting the top portion of the ring of the braiding machine with fibers of size that is greater than that of the other fibers, and without offsetting the mandrel relative to the central axis AX while forming and depositing layers of reinforcing fibers.
[0076] In the above-described examples, two implementations of the invention are described separately, i.e. firstly the possibility of loading the ring of the braiding machine with fibers of different size, and secondly the possibility of radially offsetting the mandrel relative to the axis of the braiding machine in order to obtain densities of longitudinal fibers that differ between one region and another region in each braided layer.
[0077] It should be observed that both of those approaches that are described separately above can advantageously be used in combination. For example, it is possible to load the ring of the braiding machine with longitudinal fibers of large size in the top region and with longitudinal fibers of normal size in the other regions, and also to offset the mandrel relative to the axis of the braiding machine so as to obtain an even greater difference in reinforcing fiber density.
[0078] The invention provides the following advantages in particular:
[0079] In general, the invention makes it possible to vary the thickness of material so as to reinforce and thicken zones that are subjected to greater stresses, thus making it possible to fabricate a high performance structural part at a competitive production cost.
[0080] This fabrication technique is particularly adapted to rocker type parts, i.e. to parts that are subjected to “three point” bending. Specifically, these parts are subjected to mechanical stresses that seek to bend them always in the same direction.
[0081] By way of example, for downward bending, the bottom portion of the part is stressed in traction, whereas its top portion is stressed in compression. The traction and compression stresses are of substantially the same value, but the material of the fibers generally presents compression strength that is less than its traction strength. Consequently, it is appropriate to reinforce the part in its top portion, since that is where it is subjected to compression stress, but not in its bottom portion where it is stressed in traction only. | The invention relates to a method of fabricating a mechanical member, the method including a plurality of operations of braiding and depositing layers of braided reinforcing fibers on a mandrel ( 11 ) by using braiding machine. Each operation comprises braiding a braided layer and depositing it by moving the mandrel ( 11 ) along a central axis of the braiding machine. Each of the various superposed braided layers comprises both longitudinal fibers ( 12, 12 G) that are parallel to a main direction of the mandrel ( 11 ), and interlacing fibers that are inclined. At least one operation is configured to form and deposit a braided layer having, in at least one cross-section of the member, a density of longitudinal fibers that differs depending on whether consideration is given to one angular region (S 1 ) or another angular region (S 2 ) of the same extent around the center of gravity (G) of the mandrel ( 11 ) in the section under consideration. The invention applies to fabricating structural elements in the field of aviation. | 3 |
BACKGROUND OF THE INVENTION
The present invention relates generally to an apparatus for lifting small vehicles such as motorcycles for maintenance and storage purposes.
There are many different prior art lifts designed for use with small vehicles such as motorcycles, motorbikes, snowmobiles, garden tractors, and the like. Typically, these lifts use a jack to raise a platform or arms supporting either the vehicle ground engaging portion (tires, treads, etc.) or the vehicle frame.
The U.S. Pat. No. 4,088,303 shows a boom pivoted at one end on the upper end of a post and a hydraulic cylinder for raising and lowering the boom. A platform is attached to an opposite end of the boom for supporting a vehicle.
The U.S. Pat. No. 4,460,158 shows a lift for mopeds and motorcycles having a base, a jack for raising and lowering a frame hinged to the base and a support attached to the frame for clamping the footboard of a Vespa brand moped.
The U.S. Pat. No. 4,723,756 shows a lift with four vertically telescoping legs that can be pinned in place when a jack has raised the lift to the desired height.
The U.S. Pat. No. 4,899,985 shows a low-profile hydraulic lift with a pivoted lift arm having detachable lift heads which include hooks, support yokes, chains and support harnesses.
The U.S. Pat. No. 5,211,265 shows a scissors-type snowmobile lift with rails to contact the snowmobile bellypan.
The U.S. Pat. No. 5,271,603 shows a lifting platform connected to a base by four parallel links actuated by a hydraulic jack.
U.S. Pat. No. 6,092,787 shows a manually operated motorcycle lift with a front wheel clamp and a removable extension under the unsupported rear wheel.
SUMMARY OF THE INVENTION
The present invention concerns an apparatus for lifting a small vehicle, such as a motorcycle, for various purposes such as cleaning, maintenance, repositioning from one location to another and storage. The lift apparatus includes: a base frame having a pair of ground engaging caster means and an upwardly extending center post; a pair of folding legs each having an inner end pivotally connected to the base frame and an outer end with a roller attached thereto, the casters and the rollers permitting the lift apparatus to roll across the ground surface; a parallelogram linkage having a pair of upper long links, a pair of lower long links extending generally parallel to the upper long links, an outer short link, and an inner short link formed by a portion of the center post, the upper long links being connected by first and second pivot means to the inner and outer short links respectively, the lower long links being connected by third and fourth pivot means to the inner and outer short links respectively; a vehicle support means attached to the outer short link of the parallelogram linkage; an actuator means having a lower end pivotally connected to the base frame and an upper end connected to the upper long links by a fifth pivot means whereby extension of the actuator means raises the vehicle support means between a lowered position for engaging and disengaging from a vehicle and a fully raised position a predetermined distance above the ground on which the base frame rests, the fourth pivot means being selectively operative to detach the outer short link from the lower long links and permit rotation of the vehicle support means to a storage position; and at least one of a pumping handle and a power unit connected to the actuator means for selectively activating the actuator means to raise the vehicle support means.
The actuator means can be a hydraulic cylinder and the power unit can include an electric motor driving a hydraulic pump providing pressured hydraulic fluid to the cylinder. The lift apparatus includes fastener means for selectively retaining the legs in the lowered position and in the raised position. The vehicle support means includes a pair of spaced apart support arms and vehicle attachment means connected to the support arms for holding a vehicle on the support arms, the vehicle attachment means including at least one bracket slidingly mounted on each of the support arms, each of the brackets having a vehicle engaging hook connected thereto.
DESCRIPTION OF THE DRAWINGS
The above, as well as other advantages of the present invention, will become readily apparent to those skilled in the art from the following detailed description of a preferred embodiment when considered in the light of the accompanying drawings in which:
FIG. 1 is a front elevation view of a lift apparatus in accordance with the present invention in a storage position;
FIG. 2 is rear elevation view of the lift apparatus shown in FIG. 1;
FIG. 3 is a left side elevation view of the lift apparatus shown in FIG. 1;
FIG. 4 is a right side elevation view of the lift apparatus shown in FIG. 1 in an operating position;
FIG. 5 is a fragmentary perspective view the lift apparatus shown in FIG. 1; and
FIG. 6 is a block diagram of the power unit of the lift apparatus shown in FIG. 1 .
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIGS. 1 through 5, there is shown a lift apparatus 10 designed to lift motorcycles and other small vehicles for purposes such as maintenance, repositioning and storage. In FIGS. 1-3, the lift apparatus 10 is shown in a folded position that is very compact for easy storage when not in use. A base frame 11 has a central beam 12 extending in a horizontal direction. Attached to opposite ends of the central beam 12 are vertically extending intermediate beams or legs 13 each having an upper end attached to an associated horizontally outwardly extending end beam or arm 14 . The beams 12 , 13 and 14 can be made from square steel tubing, for example, and welded together. A free end of each of the end beams 14 is cut at an angle and closed by an attached cap or plate 15 . A caster assembly 16 is attached to and extends downwardly from the bottom surface of the free end of each of the end beams 14 . The caster assemblies 16 can be any suitable commercially available product that typically includes a rubber wheel that rotates about vertical (swivel motion) and horizontal (rolling motion) axes with a foot operated brake lever 16 a for controlling the rolling motion.
Attached to a forward facing surface of each end of the central beam 12 is an inner end of each of an inner stub leg 17 and an outer stub leg 18 . The stub legs 17 and 18 extend horizontally forwardly and diverge being spaced farther apart at outer ends than at the inner ends attached to the central beam 12 . The outer legs 18 are shorter than the inner legs 17 and a first bracket plate 19 is attached to an outer side wall of each of the outer legs 18 adjacent the outer end and extends even with the outer end of the inner stub leg 17 . Apertures are formed in the inner legs 17 and the first bracket plates 19 to receive a pivot means or axles 20 in the form of a bolt and nut extending horizontally transverse to a longitudinal axis of the respective outer stub leg 18 . Positioned between the inner stub leg 17 and the bracket plate 19 is an inner end 21 a of a folding leg 21 having apertures formed therein receiving the axle 20 thereby permitting the legs to be rotated between a down or operative position (FIGS. 4-5) and an up or storage position (FIGS. 1 - 3 ). The legs 17 , 18 and 21 can be made from square steel tubing, for example, with the legs 17 and 18 welded to the central beam and the intermediate beams 13 .
A stop 22 , in the form of a short length of square tubing, is attached to an upper surface of the outer end of the outer stub leg 18 and extends beyond that outer end. A pair of second bracket plates 23 are attached to opposite side walls of the stop 22 and extend outwardly beyond the outer end of the stop. When the folding leg 21 is rotated about the axle 20 to the up position (FIGS. 1 - 3 ), the stop 22 prevents rotation beyond a generally vertical position. A fastener 24 can be inserted through apertures formed in the bracket plates 23 on the opposite side of the leg 21 from the stop 22 to prevent rotation of the folding leg from the up position back to the down position. In the down position of the folding leg 21 (FIG. 5 ), the fastener 24 can be inserted through vertically aligned apertures formed in the stop 22 and the leg 21 to retain the folding leg in the down position. A roller assembly 25 is attached to an outer end 21 b of the folding leg 21 at an angle to a longitudinal axis of the folding leg to compensate for the diverging angle of the folding legs. Thus, the roller assemblies 25 are aligned with the caster assemblies 16 during forward and rearward movement of the lift apparatus 10 .
A support platform 26 is attached to and extends generally horizontally forward from the central beam 12 . A lower end of a center post 27 is attached to an upper surface of the platform 26 and the post extends upwardly and rearwardly to an upper end to which a transversely extending handle 28 is attached. A pair of support members 29 are connected between the center post 29 and the end beams 14 . The handle 28 can be grasped by human hands for rolling the lift apparatus 10 on the caster assemblies 16 and roller assemblies 25 when the folding legs 21 are in the down position. When the folding legs 21 are in the up position, the handle 28 can be used to tilt the lift apparatus 10 rearwardly enough to lift the folding leg ends 21 a off of the ground and permit movement on the caster assemblies 16 .
A portion of the center post 27 functions as an inner short link of a parallelogram linkage having an outer short link 30 , a pair of upper long links 31 and a pair of lower long links 32 . The links 30 , 31 and 32 can be formed of square tubing. An inner end of each of the upper long links 31 is coupled on opposite sides of the center post 27 at a pivot means 33 a adjacent the handle 28 . An outer end of each of the upper long links 31 is coupled on opposite sides of the outer short link 30 at a pivot means 33 b adjacent an upper end of the short link. An inner end of each of the lower long links 32 is coupled on opposite sides of the center post 27 at a pivot means 33 c spaced below the pivot means 33 a . An outer end of each of the lower long links 32 is coupled on opposite sides of the outer short link 30 at a pivot means 33 d adjacent a lower end of the short link. The distance between the pivot means 33 a and 33 b is the same as the distance between the pivot means 33 c and 33 d , and the distance between the pivot means 33 a and 33 c is the same as the distance between the pivot means 33 b and 33 d . The pivot means 33 a through 33 d can be suitable fasteners such as bolts and nuts.
Attached to the lower end of the outer short link 30 is a transverse bar 34 extending generally parallel to the central beam 12 . Attached to and extending horizontally forward from opposite ends of the bar 34 are support bars or arms 35 upon which a motorcycle or small vehicle (not shown) can be supported. The bar 34 and the arms 35 can be formed of square tubing. A strip of padding 35 a , such as a neoprene material, can be attached to the upper surface of each of the arms 35 . The support arms 35 can be provided with vehicle attachment means 36 such as a plurality of sliding brackets 36 a each having an associated hook 36 b for cooperation with straps (not shown) that can be routed over and/or through the vehicle to prevent tipping. When the lift apparatus 10 is not in use, the pivot means 33 d can be removed permitting the outer short link 30 to rotate about the pivot means 33 b approximately 180° to a storage position a shown in FIGS. 1-3.
Attached to each of the lower long links 32 adjacent to the pivot means 33 c is a locking plate 37 having a plurality of apertures 38 formed therein. As the lower long link 32 is rotated upwardly about the pivot means 33 c , each of the apertures 38 in turn clears a front surface of the center post 27 . A pin 39 can be inserted through the corresponding ones of the apertures 38 in the plates 37 to engage the central post 27 and prevent downward rotation of the link 32 with a resultant lowering of the support arms 35 . Thus, the apertures 38 define fixed positions of the support arms 35 above the surface on which the lift apparatus 10 is resting. The pin 39 can be retained by a chain 40 attached to any suitable portion of the lift apparatus 10 such as the center post 27 .
An actuator 41 , such as a hydraulic piston and cylinder, can be used to raise and lower the support arms 35 . A bottom end of a cylinder 41 a is attached to the support platform 26 by a pivot means 42 for movement about an axis parallel to the rotation axes of the pivot means 33 a through 33 d . The actuator 41 extends between the lower long links 32 and has a piston rod 41 b extending from the cylinder 41 a with an upper end connected to the upper long links 31 at a pivot means 33 e . Thus, extending the rod 41 b from the cylinder 41 a raises the support arms 35 and retracting the rod into the cylinder lowers the support arms. The actuator 41 can be manually operated through a pumping handle 43 extending therefrom whereby repeated raising and lowering of the handle forces hydraulic fluid into a cylinder chamber (not shown) against a piston (not shown) to extend the piston rod 41 b . A release lever 44 is provided to vent the hydraulic fluid from the cylinder chamber thereby allowing the piston rod 41 b to retract into the cylinder 41 a under the weight of the supported portions of the lift apparatus 10 .
The actuator 41 also can be automatically operated utilizing a power unit 45 (shown schematically in FIG. 6) including an electric motor 46 driving a hydraulic pump 47 . The electric motor 46 can be an ac motor or a dc motor and is connected to a power source 48 through a start switch 49 . In the case of an ac motor, the power source typically would be a building electrical circuit accessed at a wall outlet. In the case of a dc motor, the power source 48 could be a storage battery 50 mounted at the rear of the central beam 12 . The power source 48 could include a converter (not shown) for changing ac power to dc power to operate the dc motor and/or charge the storage battery 50 . The motor 46 and the pump 47 are mounted on an adapter 51 with the pump being enclosed in a reservoir 52 mounted on an opposite side of the adapter from the pump. The adapter 51 can be attached to one of the intermediate beams 13 and extend behind the base frame 11 .
A control 53 is connected to the adapter 51 and to the start switch 49 for starting and stopping the motor 46 . To start the motor 46 , the control 53 is actuated to cause the start switch 49 to connect the motor to the power source 48 . The motor 46 drives the pump 47 to draw hydraulic fluid from the reservoir 52 and send pressured hydraulic fluid to the adapter 51 . The adapter 51 is connected to the actuator 41 to supply the pressured hydraulic fluid causing the actuator to raise the support arms 35 . The control 53 can be actuated to stop the motor 46 and retain the actuator 41 in a desired extended position. To lower the support arms 35 , the control 53 is actuated to release hydraulic fluid from the actuator 41 to flow through the adapter and back to the reservoir 52 .
The manually actuated version of the actuator 41 can be, for example, a commercially available long ram jack such as an eight-ton capacity hydraulic long hand jack with clevis item #14554 available from Northern Tool division of Northern Tool & Equipment Co. at “northerntool.com”. An alternative is the eight-ton capacity long ram jack with flat base item #14446 available from Northern Tool. The automatically actuated version of the actuator 41 can be a welded tee hydraulic cylinder item #908320 available from Northern Tool. The associated power unit 45 can include a Haldex Barnes Hydraulics 12 volt DC power unit item #1071 or a Haldex Bames Hydraulics 1 HP 115/208-230 Volt AC Hydraulic Power Unit item #105881, both available from Northern Tool.
In accordance with the provisions of the patent statutes, the present invention has been described in what is considered to represent its preferred embodiment. However, it should be noted that the invention can be practiced otherwise than as specifically illustrated and described without departing from its spirit or scope. | A lift apparatus includes a base frame having a pair of ground engaging caster assemblies and an upwardly extending center post, and a pair of folding legs each having an inner end pivotally connected to the base frame and an outer end with a roller attached thereto, the casters and the rollers permitting the lift apparatus to roll across the ground surface. A parallelogram linkage includes a portion of the center post and is attached to vehicle support arms. An actuator is connected between the linkage and the base frame. A pumping handle and a power unit are connected to the actuator for selectively activating the actuator to selectively raise and lower the vehicle support arms between a lowered position for engaging and disengaging from a vehicle and a fully raised position a predetermined distance above the ground on which the base frame rests. The legs and the support arms can be moved to a compact storage position when not in use. | 8 |
FIELD OF THE INVENTION
The present invention relates generally to light emitting diodes for photosensors and, more particularly, to an improved light emitting diode for a photosensor which enables correction of changes in the amount of light from a light emitting element in response to changes in the ambient temperature. The invention further relates to a photosensor using such a light emitting diode.
BACKGROUND INFORMATION
Conventionally, an apparatus has been known which transmits light from one side to the other side of a finger tip and detects changes in the transmittance (reflectance) of the transmitted light, for examining the amount of blood flowing in the finger. A resultant detected signal is then processed and the pulse rate, blood pressure and the like are evaluated by calculation. One example of a photosensor for use in such an apparatus is disclosed in Japanese Utility Model Laying-Open No. 60-158803.
FIG. 1 is a perspective view of a conventional photosensor, and FIG. 2 is a cross-sectional view of the photosensor of FIG. 1 attached to a finger.
Referring to FIG. 1, a conventional photosensor 8 transmits light from one side to the other side of a finger for detecting changes in the transmittance of the light. A light emitting element 2 and a light receiving element 3 are disposed with a predetermined spacing therebetween corresponding to the size of the finger, on an easily bendable film substrate 1. A transparent and easily bendable transparent film 6 is placed or attached to film substrate 1 to cover light emitting element 2 and light receiving element 3.
Referring to FIG. 2, the photosensor 8 is used by winding it around a finger 7 to interpose the tip of finger 7 between light emitting element 2 and light receiving element 3. A fixing tape 30 (e.g., a so-called magic tape) is attached around photosensor 8 wound around finger 7. Photosensor 8 is securely fixed on finger 7 by winding fixing tape 30 around photosensor 8 and overlapping the surface of one end of fixing tape 30 and the reverse surface of the other end thereof. When power is supplied from a signal processing unit (not shown) through a connecter 5 to a lead 4, light emitting element 2 emits light. The emitted light is transmitted through finger 7 and directed onto light receiving element 3 which receives light and transmits a resultant signal through lead 4 and connector 5 to the signal processing unit. The signal processing unit detects a change in the transmittance of the light provided at this time, processes a detected signal thereof and then evaluates the pulse rate and blood pressure value by calculation.
In general, a light emitting diode is used as the light emitting element 2 employed in the above-described photosensor 8. The light emitting diode has, however, an undesirable property in that its output power and a wavelength of light emitted from the diode vary depending on the ambient temperatures. If photosensor 8 is attached to a living body, e.g. finger 7, then finger 7 becomes ischemic or hemostatic, resulting in a decrease in the body temperature of finger 7 or in an increase in the body temperature thereof due to an increase in blood pressure. Thus, the ambient temperature of light emitting element 2 varies and its output power and its measured wavelength of light vary accordingly. However, it is desirable that the output power of light emitting element 2 and the wavelength of the light emitted from light emitting element 2 are kept constant in order to accurately measure a pulse rate or a blood pressure value.
In another disclosure a light emitting diode has been proposed which is shown in FIGS. 3A and 3B as the one satisfying the above requirements Japanese Patent Application No. 1-116757 FIG. 3A is a plan view of the kanda light emitting diode, and FIG. 3B is a side view of the diode of FIG. 3A. With reference to FIGS. 3A and 3B, a light emitting diode 10 includes two LED chips LED 1 and LED 2 disposed on a substrate 12. A photodiode PD is provided in the vicinity of LED chips LED 1 and LED 2 . Photodiode PD directly receives light emitted from chips LED 1 and LED 2 .
Photodiode PD detects a change in the amount of the light emitted from the chips LED 1 and LED 2 in accordance with a change in the ambient temperatures. A transparent epoxy resin 13 is applied onto substrate 12 to cover the chips LED 1 and LED 2 and the photodiode PD.
An operation will now be described. Photodiode PD, which is a light receiving element provided separately from the light receiving element of FIG. 1, is disposed near the chips LED 1 and LED 2 . Photodiode PD detects a change in the amount of the light from the light emitting diode in accordance with a change in the ambient temperature. A current flowing through the chips LED 1 and LED 2 is controlled so as to correct the change in the amount of the light. This feature makes it possible to keep the output power of and the wavelength of the light emitted by the chips LED 1 and LED 2 constant and thus to obtain an accurate information as to a living body.
The light emitting diode thus structured has, however, room for further improvement.
With reference to FIG. 4, since the light emitting diode 10 is used in contact with a living body 20, there are three types of light beams: a light beam designated by the dotted line 1 which is emitted from the chip LED 2 and is directly incident on photodiode PD; a light beam designated by the dotted line 2 which undergoes a total reflection from an inner surface of epoxy resin 13 and enters into photodiode PD; and a light beam designated by the dotted line 3 which once enters into living body 20 and is then scattered or reflected by living body 20, entering into photodiode PD. The amount of the scattered light or the reflected light denoted by the dotted line 3 is not constant. Accordingly, there occurs an error in a feedback apparatus for monitoring the amount of the light emitted from the chips LED 1 and LED 2 to maintain a constant light output becomes impossible.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved light emitting diode for a photosensor which is not affected by an influence caused by a drift of ambient temperatures.
Another object of the present invention is to provide an improved light emitting diode for a photosensor which enables the amount of light from a light emitting element to be kept precisely constant.
A further object of the present invention is to provide an improved light emitting diode for a photosensor which enables an accurate monitor of the amount of light from a light emitting element.
A still further object of the present invention is to provide an easily manufacturable light emitting diode for a photosensor.
A still further object of the present invention is to provide a photosensor including an improved light emitting diode which is not influenced by a drift of ambient temperatures.
To accomplish the above objects, a light emitting diode for a photosensor in accordance with the present invention includes a substrate and a light emitting element provided on the substrate. A light receiving element for receiving light emitted by the light emitting element to detect a change in the amount of the light coming from the light emitting element in accordance with a change in the ambient temperature, is disposed on the substrate and in the vicinity of the light emitting element. A first transparent layer is formed on the substrate to cover the light emitting element and the light receiving element. A second transparent layer is formed on the first transparent layer.
Preferably, at least one of the first and second transparent layers is formed of a material which intercepts light other than the wavelengths of a spectrum emitted by the light emitting element.
Preferably, an interface between the first and second transparent layers is hemispherical.
A light emitting diode for a photosensor according to another aspect of the present invention includes a substrate and a light emitting element provided on the substrate. A light receiving element which receives light emitted by the light emitting element to detect a change in the amount of the light coming from the light emitting element in accordance with a change in the ambient temperatures, is disposed on the substrate and near the light emitting element. A first transparent layer is formed on the substrate to cover the light emitting element and the light receiving element. A second transparent layer is formed on the first transparent layer. A refractive index n 1 of the first transparent layer and a refractive index n 2 of the second transparent layer satisfy the following inequality: n 1 ≧n 2 .
A photosensor according to still another aspect of the present invention includes a light emitting diode of the present invention having the foregoing characteristics.
In accordance with a light emitting diode for a photosensor according to the present invention, a second transparent layer is formed on a first transparent layer. Thus, a very thin air layer is enclosed between the first and second transparent layers when the second transparent layer is applied over the first transparent layer. The refractive index of air is smaller than those of the first and second transparent layers, whereby the number of optical paths of the light, which is emitted by the light emitting element increases and the emitted light is subjected to a total reflection by an inner surface of the first transparent layer whereby the reflected light incident on the light receiving element also increases. This feature makes it possible to substantially neglect the amount of the light which enters in a living body and then is reflected therefrom. Consequently, the amount of the light emitted by the light emitting element, which is directly received by the light receiving element, increases. When the refractive index n 1 of the first transparent layer is larger than the refractive index n 2 of the second transparent layer, the number of optical paths of the light emitted by the light emitting element increases, whereby the emitted light undergoes a total reflection at the interface between the first and second transparent layers and the reflected light entering into the light receiving element also increases. This makes it possible to substantially neglect the amount of the light which enters into and then reflects from the living body. Consequently, the amount of the light emitted from the light emitting element, which is directly received by the light receiving element increases.
A photosensor including a light emitting diode of the invention having the foregoing characteristics, permits a precise measurement immune to since it is not influenced by a drift of temperature.
The foregoing and other objects, features, aspects and advantages of the present invention will become more apparent from the following detailed description of the present invention when taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a conventional photosensor.
FIG. 2 is a cross-sectional view of the photosensor of FIG. 1 attached to a finger.
FIG. 3A is a plan view showing one example of a conventional light emitting diode; and FIG. 3B is a side view of the light emitting diode of FIG. 3A.
FIG. 4 is a diagram for use in explaining the operation of the conventional light emitting diode.
FIG. 5 is a side view of a light emitting diode for a photosensor according to a first embodiment of the present invention.
FIG. 6 is a side view for use in explaining an operation of the light emitting diode for a photosensor according to said first embodiment.
FIG. 7 is a diagram showing a transparence property of an epoxy resin of the type which limits a wavelength band, used in the present invention.
FIG. 8 is a side view of a light emitting diode for a photosensor according to a second embodiment of the present invention.
FIG. 9 is a side view for use in explaining an operation of the light emitting diode shown in FIG. 8.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 5 is a side view of a light emitting diode for a photosensor according to the first embodiment of the present invention. The light emitting diode for a photosensor includes a substrate 12. LED chips LED 1 (not shown) and LED 2 serving as light emitting elements are disposed on substrate 12. A photodiode PD receives light emitted by the chips LED 1 and LED 2 for detecting a change in the amount of light from these LED chips in response to a change in ambient temperatures. The photodiode PD is provided on substrate 12 and in the vicinity of the LED chips. A hemispherical transparent molding material such as a glass epoxy or the like, which forms a first transparent layer 21, is formed on substrate 12 to cover the chips LED 1 and LED 2 and the photodiode PD. A hemispherical transparent molding material such as a glass epoxy or the like, which is a second transparent layer 22, is formed on the first transparent layer 21. At least one of the first and second transparent layers 21 and 22 is preferably formed of a material which intercepts light other than a wavelength of a spectrum emitted by the chips LED 1 and LED 2 . In the first embodiment, the first transparent layer 21 employs an epoxy resin of the type which has a transparence property shown in FIG. 7 and limits a wavelengths band. Referring to FIG. 7, the curve (1) represents the transparence property of the epoxy resin for limiting the wavelength band. λ 1 designates a wavelength in a spectrum emitted by LED 1 and λ 2 designates a wavelength in a spectrum emitted by LED 2 . The epoxy resin is appropriately selected from resins, for example, Toray Hysol THL-5000A/B, HL3000 (S), EX-012/HX-021-3 and the like manufactured by Toray Hysol Co., Ltd.
A very thin air layer 200 is formed at an interface between the first and second transparent layers 21 and 22 when the second transparent layer 22 is applied over the first transparent layer 21. The refractive index of this air layer is smaller than those of both the first and second transparent layers 21 and 22.
The operation will now be described, with reference to FIG. 6. The light emitting diode for a photosensor is applied to contact a living body 20. Since the air layer 200 with a small refractive index is formed at an interface 200 between the first and second transparent layers 21 and 22, a portion of light emitted by the chips LED 1 and LED 2 undergoes a total reflection at the interface 200 and then reaches the photodiode PD, as shown by the dotted line 5. Since the amount of the light subjected to the total reflection increases, the amount of the light emitted by the chips LED 1 and LED 2 and which is directly received by the photodiode PD, increases.
Light which is scattered or reflected by the living body 20 as shown by the dotted line 6, of the light emitted by the chips LED 1 and LED 2 and then entering into the living body 20, is reflected at the air layer interface 200 and hence does not reach the photodiode PD. In addition, since the first transparent layer 21 employs the epoxy resin, which has the transparence property shown in FIG. 7 which limits a wavelengths band, other light indicated by the solid line 7 with a wavelength other than the wavelength of the light emitted by the chips LED 1 and LED 2 cannot be incident on the first transparent layer 21 because the light 7 is intercepted at interface 200.
Due to the just described construction of the light emitting diode for a photosensor according to the invention of light emitted by the LED chips and directly incident on the photodiode increases, thereby making it possible to disregard the amount of light which is reflected by the living body and enters into the photodiode. This enables a precise feedback and consequently a precise measurement independently of any to influence caused by a drift of temperatures.
Although an epoxy resin is used for the first and second transparent layers 21 and 22 in the foregoing embodiment, the present invention is not limited to this material and any transparent body, for example, glass or an elastomer may be used.
While no specific explanation has been given on the thickness of the air layer, the air layer may have a thickness which arises naturally when molding the second transparent layer on the first transparent layer. In further detail, the thickness of the air layer may merely be larger than the wavelength of the light emitted by the LED chips.
Moreover, while in the example the first and second transparent layers 21 and 22 are hemispherical, the present invention is not limited to this feature. However, formation of the transparent layers 21 and 22 in a hemispherical shape has the advantage of facilitating the manufacture of these transparent layers.
FIG. 8 is a side view of a light emitting diode for a photosensor according to another embodiment of the present invention, including a substrate 12. LED chips LED 1 (not shown) and LED 2 serving as light emitting elements are provided on substrate 12. A photodiode PD receives light emitted by the chips LED 1 and LED 2 for detecting a change in the amount of the light from the LED chips in accordance with a change in ambient temperature, is provided on the substrate 12 and near the LED chips. A hemispherical transparent molding material such as a glass epoxy or the like, which forms a first transparent layer 21, is formed on substrate 12 to cover the chips LED 1 and LED 2 and the photodiode PD. A hemispherical transparent molding material such as of a glass epoxy or the like, which forms a second transparent layer 22, is formed on the first transparent layer 21. The refractive index n 1 of the first transparent layer is larger than the refractive index n 2 of the second transparent layer. The above-described clear epoxy resin is appropriately selected from resins, for example, Toray Hysol THL-5000A/B, HL3000 (S) and EX-012/HX-021-3 manufactured by Toray Hysol Co., Ltd. The refractive indexes are adjusted by changing the compositions of the resins or by changing the mixing ratios of the resins. In the manufacturing of the present device the first transparent layer 21 which is clear epoxy, is first hardened and then the second transparent layer 22 which is also a clear epoxy, is applied and hardened.
A very thin air layer 200 in FIG. 8 is formed at an interface between the first and second transparent layers 21 and 22 in the step of forming the second transparent layer 22 on the first transparent layer 21.
The operation will now be described.
Referring to FIG. 9, the light emitting diode for a photosensor is applied to contact a living body 20. Since refractive index n 1 of first transparent layer 21 is larger than n 2 of the second transparent layer 22, a portion of the light emitted by the chips LED 1 and LED 2 undergoes a total reflection at the interface and reaches the photodiode PD, as shown by the dotted line 5. In this embodiment, since the amount of the light subjected to the total reflection increases, the amount of the light emitted by the LED chips, which is directly received by the photodiode PD, also increases.
The light scattered or reflected by the living body 20 shown by the dotted line 6, of the light which is emitted by the chips LED 1 and LED 2 , is then incident on the living body 20, undergoes a total reflection at the interface between the first and second transparent layers 21 and 22 and thus does not reach the photodiode PD.
By eliminating light scattering by the living body from the measurement; it becomes possible to retain a constant amount of light and obtain a precise feedback, thereby assuring a precise measurement independently of any influence caused by a drift of temperatures.
Although the present invention has been described and illustrated in detail, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation, the spirit and scope of the present invention being limited only by the terms of the appended claims. | A light emitting diode for a photosensor is so constructed that ambient temperature drifts are prevented from adversely affecting a measurment. The light emitting diode for a photosensor has a substrate (12) carrying a light emitting element (LED 2 ) and a light receiving element (PD) for sensing light emitted by the light emitting element (LED 2 ) thereby to detect a change in the amount of light from the light coming emitting element (LED 2 ) in accordance with a change in the ambient temperature. For this purpose a first transparent layer (21) is provided on the substrate (12) to cover the light emitting element and the light receiving element (PD). A second transparent layer (22) is provided on the first transparent layer (21). A very thin air layer is interposed between the first and second transparent layer. | 7 |
CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application is a continuation of copending International Application No. PCT/EP00/09457, filed Sep. 27, 2000, which designated the United States.
BACKGROUND OF THE INVENTION
[0002] Field of the Invention
[0003] The invention relates to a method and also a timing circuit for generating a switching or control signal after a predeterminable period of time.
[0004] Timing circuits for switching off a load are usually constructed as so-called RC circuits with a RC element that serves as a timing element.
[0005] In electronic ignition systems for internal combustion engines, by way of example, the ignition coil is switched off in such a way that an ignition spark is no longer produced at the spark plug if the drive is operating defectively. The ignition coil can be switched off for example if a maximum temperature is exceeded in the electronic switch that switches the ignition coil on and off. It is more advantageous, however, for the ignition coil to be switched off a predeterminable time after the switch-on process. The predeterminable period of time is chosen to be longer than the switch-on time of the ignition coil in the case of disturbance-free operation. In an electronic ignition system, the switch-on and switch-off times lie in a range of approximately 10 ms to 50 ms.
[0006] A timing circuit is suitable for switching off the ignition coil. By way of example, the RC circuit can be used for this purpose, but has the disadvantage that the capacitor cannot be integrated on a chip, but rather has to be provided as an external component. Another, integral solution provides the use of an oscillator and a plurality of binary divider stages. Although this solution has the advantage that all the components can be integrated, it nonetheless requires a high outlay on circuitry.
SUMMARY OF THE INVENTION
[0007] It is accordingly an object of the invention to provide a method and a timing circuit for generating a switching or control signal that overcome the above-mentioned disadvantages of the prior art methods and devices of this general type, in which the switching or control signal is formed after a predeterminable period of time, in particular for switching off the ignition coil of an electronic ignition system, which can be integrated without a high outlay on circuitry.
[0008] With the foregoing and other objects in view there is provided, in accordance with the invention, a method for generating a control signal after a predeterminable period of time. The method includes the steps of applying a voltage to an inductor at a beginning of a time measurement; and outputting, via a current threshold value detector, the control signal if a current through the inductor exceeds a predeterminable threshold value.
[0009] The method according to the invention achieves the object by virtue of the fact that at the beginning of the time measurement, a voltage is applied to an inductor, and that a current threshold value detector outputs the switching or control signal if the current through the inductor exceeds a predetermined threshold value.
[0010] In terms of the apparatus, the object is achieved by virtue of the fact that an electric circuit contains a voltage source, a controllable switch, an inductor and also a current threshold value detector with a control output.
[0011] In the method according to the invention, the inductor is provided as a timing element. The rise of the current through the inductor is detected by a current threshold value detector, which, in the event of an adjustable and predeterminable threshold value being exceeded, outputs the switching or control signal that, for example, can switch a load on or off. The method according to the invention can be used particularly advantageously in an electronic ignition system of an internal combustion engine, because the ignition coil that is present anyway can serve as the timing element.
[0012] A first exemplary embodiment of the method according to the invention provides for the current through the inductor to be detected by a measuring resistor, to whose connections a voltage threshold value detector is connected.
[0013] A second exemplary embodiment of the method according to the invention provides for the voltage drop and the current rise at the inductor to be measured and logically combined with one another in a logic circuit. The logic circuit generates the switching or control signal.
[0014] A third exemplary embodiment of the method according to the invention is used in an electronic ignition system of an internal combustion engine. The already mentioned current threshold value detector or voltage threshold detector or the logic circuit drives the electronic switch of the electronic ignition system, which switches the ignition coil on and off. After the predetermined period of time, the current threshold detector, the voltage threshold value detector or the logic circuit outputs a switching signal for switching off the ignition coil.
[0015] A fourth exemplary embodiment of the method according to the invention, when used in an electronic ignition system for an internal combustion engine, provides for the current through the ignition coil to be switched off in the event of a short circuit on the ignition coil.
[0016] In accordance with an added mode of the invention, there are the steps of flowing the current through a measuring resistor, and measuring a voltage drop across the measuring resistor using a voltage threshold value detector, the voltage drop serving as a measure of the current through the inductor.
[0017] In accordance with an additional mode of the invention, there are the steps of measuring a current rise at the inductor, and logically combining the voltage drop and the current rise in a logic circuit, and the logic circuit generates the control signal.
[0018] In accordance with another mode of the invention, there is the step of using the current threshold value detector, the voltage threshold value detector or the logic circuit to drive an electronic switch, the electronic switch switches off the current through the inductor.
[0019] In accordance with a further mode of the invention, there are the steps of measuring the current rise at the inductor and a voltage drop across the electronic switch, and logically combining the current rise and the voltage drop across the electronic switch with one another in the logic circuit. As a result the logic circuit outputs the control signal.
[0020] In accordance with a further added mode of the invention, there is the step of using the inductor as an ignition coil of an ignition system of an internal combustion engine.
[0021] In accordance with a further additional mode of the invention, there is the step of switching off the current through the ignition coil in an event of a short circuit on the ignition coil.
[0022] In accordance with another further mode of the invention, there is the step of switching off the current through the ignition coil with regards to a differential quotient dI/dt which is chosen to be small enough that no ignition spark is generated at spark plugs connected to the ignition coil.
[0023] In accordance with a concomitant mode of the invention, there is the step of forming the control signal as a switching signal.
[0024] With the foregoing and other objects in view there is provided, in accordance with the invention, a timing circuit for generating a control signal after a predeterminable period of time. The timing circuit contains an electric circuit having a voltage source, a controllable switch connected to the voltage source, an inductor connected to the controllable switch, and a current threshold value detector with a control output connected to the inductor.
[0025] In accordance with an added feature of the invention, the current threshold value detector has a voltage threshold value detector with a control output and a measuring resistor connected in parallel with the voltage threshold value detector.
[0026] In accordance with an additional feature of the invention, the controllable switch has a control input; and the inductor is a primary winding of an ignition coil of an electronic ignition system of an internal combustion engine. The control output of the current threshold value detector is connected to the control input of the controllable switch.
[0027] In accordance with another feature of the invention, the controllable switch has a control input; and the inductor is a primary winding of an ignition coil of an electronic ignition system of an internal combustion engine. The control output of the voltage threshold value detector is connected to the control input of the controllable switch.
[0028] In accordance with a further feature of the invention, the controllable switch is a field-effect transistor. More specifically, the field-effect transistor is an insulated gate bipolar transistor.
[0029] In accordance with a further added feature of the invention, the voltage source has a first pole and a second pole. The controllable switch is a field-effect transistor having a collector terminal, a gate electrode, a first emitter terminal and a second emitter terminal. The current threshold value detector has a further voltage threshold value detector with a first input, a second input, a third input and an output. The current threshold value detector has a logic circuit with a first input, a second input, a first output and a second output. The primary winding of the ignition coil has a first terminal connected to the first pole and to the first input of the further voltage threshold detector, a second terminal connected to the second input of the further voltage threshold value detector and to the collector terminal of the field-effect transistor. The first emitter of the field-effect transistor is connected through the measuring resistor to the gate electrode of the field-effect transistor, to the first output of the logic circuit, to the third input of the further voltage threshold value detector and to the second pole of the voltage source. The measuring resistor has a first terminal connected to the first input of the voltage threshold value detector. The voltage threshold value detector has an output connected to the first input of the logic circuit. The output of the further voltage threshold value detector is connected to the second input of the logic circuit. The second output of the logic circuit is connected to the gate electrode of the field-effect transistor.
[0030] In accordance with a concomitant feature of the invention, the second emitter terminal of the field-effect transistor is connected in parallel with a series circuit of the first emitter terminal and the measuring resistor.
[0031] Other features which are considered as characteristic for the invention are set forth in the appended claims.
[0032] Although the invention is illustrated and described herein as embodied in a method and a timing circuit for generating a switching or control signal, it is nevertheless not intended to be limited to the details shown, since various modifications and structural changes may be made therein without departing from the spirit of the invention and within the scope and range of equivalents of the claims.
[0033] The construction and method of operation of the invention, however, together with additional objects and advantages thereof will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] [0034]FIG. 1 is a block circuit diagram of a first exemplary embodiment of a timing circuit according to the invention;
[0035] [0035]FIG. 2 is a block circuit diagram of a second exemplary embodiment of the timing circuit according to the invention; and
[0036] [0036]FIG. 3 is a block circuit diagram of a third exemplary embodiment of the timing circuit according to the invention, the third exemplary embodiment being incorporated in an electronic ignition system for an internal combustion engine.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0037] Referring now to the figures of the drawing in detail and first, particularly, to FIG. 1 thereof, there is shown a first exemplary embodiment of a timing circuit according to the invention which will now be described and explained.
[0038] An electric circuit contains a voltage source U, a controllable switch S, an inductor L and a current threshold value detector ID with a control output.
[0039] The timing circuit is switched on by the closing of the controllable switch S, which can be actuated by a control circuit, for example. If a current I through the inductor L exceeds a predeterminable and adjustable threshold value, the current threshold value detector ID outputs at its output a switching or control signal which, for example, may serve for controlling or switching a load on and off.
[0040] When the first exemplary embodiment of the timing circuit according to the invention is used in an electronic ignition system for an internal combustion engine, the control output of the current threshold value detector ID is connected to a control input of the controllable switch S, which switches the inductor L-the ignition coil-on and off.
[0041] The second exemplary embodiment—shown in FIG. 2—of the timing circuit according to the invention will now be described and explained.
[0042] The construction of the current threshold value detector ID is shown in the second exemplary embodiment of the timing circuit according to the invention shown in FIG. 2. The electric circuit contains the voltage source U, the controllable switch S, the inductor L and a measuring resistor R, to whose connections a voltage threshold value detector UD 1 is connected. The measuring resistor R and the voltage threshold value detector UD 1 form the current threshold value detector ID.
[0043] The second exemplary embodiment can also be used in an electronic ignition system. A control output of the voltage threshold value detector UD 1 is connected to the control input of the controllable switch S, which switches the ignition coil L on and off.
[0044] The third exemplary embodiment of the timing circuit according to the invention, the third exemplary embodiment being incorporated in an electronic ignition system and is shown in FIG. 3, will now be described and explained.
[0045] In FIG. 3, one connection of a primary winding PW of the ignition coil L is connected to one pole of the voltage source U-the vehicle battery-and a first input of a second voltage threshold detector UD 2 . A second connection of the primary winding PW of the ignition coil L is connected to the second input of the second voltage threshold value detector UD 2 and to a collector of a field-effect transistor T, which constitutes the controllable switch S. A first emitter of the field-effect transistor T is connected through the measuring resistor R to its gate electrode, to a first output A 1 of a logic circuit LS, to a third input of the second voltage threshold value detector UD 2 and to the other pole of the voltage source U. One connection of the measuring resistor R is connected to a first input of the first voltage threshold value detector UD 1 and the other connection of the measuring resistor R is connected to the second input of the first voltage threshold value detector UD 1 . An output of the first voltage threshold value detector UD 1 is connected to the first input of the logic circuit LS. The output of the voltage threshold value detector UD 2 is connected to the second input of the logic circuit LS, whose second output A 2 is connected to the gate electrode of the field-effect transistor T. A second emitter of the field-effect transistor T is connected in parallel with the first emitter of the field-effect transistor T and with the measuring resistor R. A zener diode Z is connected in parallel with the gate electrode and with the emitter of the field-effect transistor T.
[0046] A so-called insulated gate bipolar transistor is preferably used for the field-effect transistor T.
[0047] The function of the third exemplary embodiment of the invention shown in FIG. 3 will now be explained.
[0048] The current through the primary winding PW of the ignition coil L is switched on and off cyclically by the field-effect transistor T, in order to generate an ignition spark at the correct instant at the spark plugs connected to the secondary winding SW of the ignition coil L. When the field-effect transistor T is in the on state, the current I through the primary coil PW of the ignition coil L rises linearly. According to the invention, the linear rise of the current I serves for time measurement purposes.
[0049] In the case of disturbance-free operation, the field-effect transistor T is switched on and off cyclically, in order that the ignition coil supplies the ignition voltage required for the spark plugs at the correct instant. If no ignition spark is generated at the ignition instant on account of a disturbance, the current I through the primary winding PW of the ignition coil L continues to rise linearly. In order to prevent the ignition coil from being destroyed by excessively high current, the field-effect transistor T is controlled by the logic circuit LS from the on state to the off state so slowly that the differential quotient dI/dt of the current flowing through the primary winding PW of the ignition coil L remains small enough that the ignition voltage induced on the secondary winding SW of the ignition coil L no longer suffices to generate an ignition spark at the spark plugs. Ignition sparks outside the ignition instance are thereby avoided.
[0050] The voltage threshold value detector UD 1 detects a voltage drop across the measuring resistor R, which is proportional to the current I flowing through the primary winding PW of the ignition coil L. The voltage threshold value detector UD 2 detects the voltage drop across a collector-emitter path of the field-effect transistor T. The threshold value set in the voltage threshold value detector UD 1 is chosen to be greater than the value of the voltage drop across the measuring resistor R at the ignition instant. In the case of disturbance-free operation, the value set in the voltage threshold value detector UD 1 is therefore never reached. By contrast, the current I through the primary coil PW and thus the voltage drop across the measuring resistor R rise in the event of a disturbance, that is to say if the field-effect transistor T is not switched off at the ignition instant, beyond the threshold value set in the voltage threshold value detector UD 1 . At the same time, the voltage across the collector-emitter path of the field-effect transistor T, which is detected by the voltage threshold value detector UD 2 , falls below the collector-emitter saturation voltage. If both the first condition, wherein the current I through the primary winding PW of the ignition coil L exceeds the predeterminable threshold value, and the second condition, wherein the voltage across the collector-emitter path of the field-effect transistor T equals or becomes < the collector-emitter saturation voltage, the logic circuit LS outputs a control signal to the gate electrode of the field-effect transistor T, which transfers the latter from the on state to the off state so slowly that the differential quotient ID/dT of the current I flowing through the primary winding PW of the ignition coil L no longer suffices to induce, on the secondary winding SW of the ignition coil L, an ignition voltage having a magnitude required to generate an ignition spark.
[0051] In the event of a short circuit on the ignition coil L, the collector-emitter voltage of the field-effect transistor T significantly exceeds the saturation voltage, and this is detected by the voltage threshold value detector UD 2 . When the collector-emitter voltage of the field-effect transistor T significantly exceeds the saturation voltage, the voltage threshold value detector UD 2 outputs a control signal to the logic circuit LS, which thereupon immediately controls the field-effect transistor T into the off state. In the event of a short circuit on the ignition coil L, the current through the primary winding PW of the ignition coil L can be immediately switched off, because, in this case, no voltage is induced in the secondary winding SW of the ignition coil L and, therefore, no ignition spark can be generated either.
[0052] Since the inductor L is provided as the timing element in the method according to the invention and in the timing circuit according to the invention, neither a RC element nor an oscillator with subsequent binary divider stages is necessary. The invention is therefore suitable in particular for an electronic ignition system, because an electronic ignition system contains an inductor—the ignition coil—anyway, which performs a dual function. It generates the ignition voltage and simultaneously serves as the timing element. The invention is particularly well suited to circuit configurations or systems in which an inductor is provided, which can then additionally be utilized as a timing element.
[0053] However, the invention is in no way restricted to such circuits or systems having an inductor already present. It can advantageously be used whenever comparatively long times are to be measured. If an inductor is not already present in the area of application, and it can be utilized as a timing element, an inductor should be provided as the timing element.
[0054] The ignition system according to the invention requires only two voltage threshold value detectors and a logic circuit, which constitute only a small outlay and, moreover, can easily be integrated on a chip. | A method for generating a control signal after a predeterminable period of time is described. The method includes applying a voltage to an inductor at a beginning of a time measurement; and outputting, via a current threshold value detector, the control signal if a current through the inductor exceeds a predeterminable threshold value. The invention also relates to a timing circuit. | 5 |
This is a continuation of application Ser. No. 638,435, filed Dec. 8, 1975, now abandoned.
BACKGROUND OF THE INVENTION
This invention relates to apparatus for wrapping tape around an article and in particular to apparatus for wrapping tape around the ends of stator coils.
Apparatus for wrapping coils or wires with tape typically involve many moving parts such as rollers, smoothing arms, and the like. Because of the number of parts, such apparatus are relatively expensive and complex. In addition, because such parts normally require considerable space in which to perform the taping operation, it is difficult to perform several taping operations simultaneously within a small area, as may be needed, for example, to tape the coil ends of a multi-coil stator.
SUMMARY OF THE INVENTION
An apparatus embodying the present invention wraps tape around an article in several simple mechanical steps, has a minimum number of moving parts, and requires little working area during its operation. The apparatus is particularly useful in wrapping tape about the ends of coils mounted on stator cores where there is little available space for performing the wrapping operation.
In accordance with the present invention, an apparatus for wrapping tape about an article is provided with two clamping members. The clamping members cooperate to receive a leading end of the tape from one side of the article and a trailing end of the tape from the opposite side of the article. The clamping members then draw the trailing end tightly about the article and press it to the leading end.
In the illustrated apparatus, there is also included tape feed means, a tape press member, and tape engaging means. A strip of tape is fed by the tape feed means so that the leading end is moved in a direction along a first side of the article to a position where it is clamped by the clamping members. The tape press means then presses a section of the tape adjacent the leading end to the first side of the article and also acts to bend the trailing end partially around the article. The tape engaging means further bends the trailing end around the article and in a direction along the side opposite the first side to a position where it also is received between the clamping members. The clamping members are returned toward their initial position which causes the trailing end, as previously mentioned, to be drawn tightly around the article and pressed to the leading end, thereby completing the taping operation. The apparatus and its operation can be modified to either press the leading and trailing ends together to form a tab projecting from the article or to press the ends together and to the article, the trailing end over the leading end, so that no tab is formed.
In the embodiments described, the apparatus is used to tape the end of a coil mounted on a stator. The first of the movable clamping members is the margin bounding an aperture in a tool member. The tool member is quite narrow and thin and thus movable between the coil end and the end face of the stator. The second clamping member is an extension of the tape press member. The extension is contained within the aperture of the tool member and the tape press member is slidably mounted on the tool member. The movement of the tape press member is toward and away from the radially outward side of the coil end. The tape press member has a contoured surface which presses the adjacent section of tape to a radially outward side of the coil. A tape ram acts as the tape engaging means, moving along the longitudinal axis of the stator to bend the trailing end about the coil end.
Since the work space needed for the moving parts can be quite small, an apparatus in accordance with the present invention is particularly adaptable for cooperating with several identical apparatus to perform simultaneous taping operations on several coil ends on a single stator core. Because of the minimum number of moving parts and the small working area required, there is no interference by the parts of one apparatus with another. In fact, plural simultaneously operating apparatus could be designed to use a common tape engaging means to further simplify the construction of the apparatus.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a stator coil taping apparatus in accordance with this invention and a stator located with one of its coils positioned to be taped.
FIG. 2 is a side elevational view, partially in section and partially broken away, of the taping apparatus of FIG. 1 prior to the beginning of the taping operation.
FIG. 3 is a sectional view of a portion of the taping apparatus, taken along the line 3--3 of FIG. 2.
FIGS. 4 through 10 are side elevational views, each showing parts of the apparatus shown in FIG. 1 and illustrating the sequence of operation thereof.
FIG. 11 is a perspective view, partially broken away, of the stator core and coil after the coil end has been taped by the apparatus shown in FIGS. 1 through 10.
FIG. 12 is a sectional view of a portion of a modified taping apparatus in accordance with this invention.
FIGS. 13 through 17 are sectional views, each showing the portion of the modified apparatus of FIG. 12 and illustrating the sequence of operation thereof.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, the reference number 20 designates the taping apparatus of the present invention. Portions of the taping apparatus can be seen to be assembled upon a rear plate 46 which is butt welded to the rear side, as appears in FIG. 1, of a tapered guide plate 40. The plates 40 and 46 which, by reason of welding, comprise a rigid assembly are supported by means of a fixed beam 34 to which the plate 40 is anchored by means of fastener means 47. The assembly is also supported by a bracket member 21 fixedly attached to the right end of the plate 46 as it appears in FIG. 1. By means not shown, the beam 34 and the bracket 21 are fixedly attached to a stator winding mechanism which, being old and well known in the art, is not illustrated in the drawings.
Appearing to the lower front of FIG. 1 is a track 36 onto which stator cores 26 wound by the winding mechanism are discharged, one such stator core 26 having been advanced by a mechanism (not shown) along the track 36 to the position shown in FIG. 1 where the stator core is at rest. A second track, which has been omitted from the drawings for purposes of clarity, is attached to beam 34 so as to be located above the stator core 26 and to generally confront track 36. This second track cooperates with track 36 to confine the stator core 26 and prevent movement thereof during the taping operation.
Welded to the guide plate 40 is a front guide plate 38, and welded to the guide plate 38 in spaced apart relation to the guide plate 40 is a guide bar 42. The guide bar 42, being spaced from the guide plate 40, provides a vertically disposed channel 44 in which an elongate tool member 48 is retained against lateral movement out of the channel 44 by means of plate members 49 which are bolted to the guide plate 40 and to the guide bar 42, as shown in FIG. 3.
With the foregoing preliminary remarks concerning the general support for the taping apparatus 20, attention will now be given to the specific structure of the taping apparatus.
The taping apparatus 20 is used to apply tape to an end 22 of a coil 24 mounted on the stator core 26. With reference to FIGS. 2 and 11, the coil end 22 is that portion of the coil 24 that projects from an end face 28 of the stator core 26. Relative to the longitudinal axis of the core 26, the end 22 has a radially outward side 30 and a radially inward side 32.
As shown best in FIGS. 2 and 3, and for reasons which will become apparent from the following description, a channel 51 is formed centrally of the rear face of the tool member 48. The lower end of the tool member 48 terminates in a frame portion 53 which is apertured to form a window 50. Guide plates 52 are attached to the tool member 48 along each side of the channel 51. A tape press member 54 is confined by the guide plates 52 in channel 51 for vertical sliding movement relative to the tool member 48.
As apparent in FIG. 3, the tape press member 54 is of generally a T shape so as to interfit the channel 51 and to be retained by the guide plates 52. As appears in FIG. 2, the tape press member 54 has an extension 56 which protrudes into the window 50. The extension 56 has a lowermost clamping surface 58 which, as seen in FIG. 3, confronts a lower clamping surface 60 on a lower margin 62 of the frame portion 53. As best appears in FIG. 2, the tape press member 54 also has a contoured tape press surface 64 disposed adjacent the aforementioned extension 56 and, when the stator 26 is in the position shown in FIG. 2, the surface 64 is located directly above the outward side 30 of the coil end 22. The surface 64 is so contoured as to generally interfit the outward side 30 of the coil end 22 when, as will be described, the tape press member 54 is moved downwardly to engage the coil end 22.
A dual air cylinder 66 is attached by a fastener 72 to a protruding arm 70 affixed to side guide bar 42. Dual air cylinder 66 has an upper air cylinder 78 and a lower air cylinder 80. The upper air cylinder 78 has an actuator rod 79 affixed to a bracket member 77 projecting outwardly from the tool member 48 by means of a nut 76. The lower air cylinder 80 includes an actuator rod 81 which is connected to the tape press member 54 by means of a nut 83.
The air cylinders 78 and 80 and the other air cylinders shown in the drawings are conventional and are operated by compressed air. The air supply valves, hoses and switches which control the operation of the air cylinders are well known and thus are not shown or described in detail.
As apparent in FIG. 2, one of the air hose connections 74 to the dual air cylinder 66 is accommodated by a slot 75 located in the tool member 48. The slot 75 allows the dual acting air cylinder 66 to raise and lower the tool member 48 without destruction to the air hose 74.
It can be noted that the dual air cylinder 66 is fixedly mounted by means of the fastener 72. In general operation, energization of the upper air cylinder 78 vertically moves the tool member 4, and energization of the lower air cylinder 80 vertically moves the tape press member 54. As the tape press member 54 is lowered, the clamping surface 58 of the tape press member 54 is caused to approach the clamping surface 60 of the tool member 48.
A variety of operations can be caused to occur. As one example, the air cylinder 80 may hold the tape press member 54 stationary, and the air cylinder 78 may be actuated to raise the tool member 48, thereby effecting a clamping action between the clamping surface 58 of the tape press member 54 and the clamping surface 60 on the margin 62 of the tool member 48. As a further example, the air cylinder 78 may be actuated to lower the tool member 48 away from the tape press member 54, thus creating an opening through the window 50. As a further possibility, the air cylinder 80 may be actuated at the same time the air cylinder 78 is actuated oppositely, whereupon the two air cylinders are pitted one against the other. By reason of the design of the dual air cylinder 66, the air cylinder 80 is capable of overpowering the air cylinder 78, the consequence being that the air cylinder 80, acting upon the tape press member 54, moves both the tape press member 54 and the tool member 48 downwardly, as appears in FIG. 2, against the upward thrust of the air cylinder 78 on tool member 48. The various operating modes of the dual air cylinder 66 will be more particularly described in ensuing remarks when the operation of the apparatus to wrap the tape about a coil end is described.
The tape source for the apparatus 20 is a tape spool 82 rotatably mounted on rear plate 46. Adhesive tape 84 withdrawn from the spool 82 by a mechanism to be described is guided by tape wheels 86 pivotally mounted to the plate 46 to a tape advancing mechanism 88. In the preferred embodiment, the tape 84 is an adhesive tape, the adhesive side of which faces away from the wheels 86. It should be apparent, however, that other types of tape or binding material can be utilized without deviating from the scope of the present invention.
The tape advancing mechanism 88 includes an air cylinder 108 which is pivotally mounted by means not appearing in the drawing to a plate 109 which is in turn affixed to the rear plate 46. The air cylinder 108 positions a clevis arm 110 to which a lower tape jaw 94 is pivotally secured by a pin 112. The lower tape jaw 94 is pinned by means of pin 104 to a jaw bracket 106 which is affixed to an elongate upper tape jaw 90. The upper tape jaw 90 can be seen to extend horizontally below the air cylinder 108 and between supporting plates 102 which are affixed to the aforementioned plate 109.
The upper tape jaw 90 has a gripping portion 92 projecting forwardly from the plane of FIG. 2 so as to project through a slot 98 extending through the rear plate 46, thus to have access to the tape 84, as shown in FIG. 1. Likewise, the lower tape jaw 94 has a gripping portion 96 which projects forwardly from the plane of FIG. 2 to also enter the slot 98 located in the rear plate 46. The gripping portion 96 of the lower tape jaw 94 does not appear in detail in FIG. 1 because substantially concealed by the gripping portion 92 in slot 98.
The air cylinder 108 is a double acting cylinder and, when urging the clevis 110 to the left as appears in FIG. 2, urges the gripping portion 96 of the lower jaw 94 upwardly toward the gripping portion 92 of the upper jaw 90 so as to grip the leading end 100 of the tape 84 therebetween. Continued operation of the air cylinder 108 to the left as appears in FIG. 2 then functions to advance the leading end of the tape 84 toward the window 50 located in the tool member 48, the distance of such advance being limited as by the stroke length of the cylinder 108. As will be later described more fully, the dual air cylinder is then actuated to cause the tape 84 to be seized and retained between the clamp surfaces 58 and 60. Upon reversal of the direction in which the air cylinder 108 moves the clevis 110, the first action to occur will be a downward swing of the lower jaw 94 about the axis of the pin 104 to release the tape 84. Continued movement of the clevis 110 to the right as appears in FIG. 2 will cause the pin 112 to drivingly engage the jaw bracket 106, thus advancing both the lower jaw 94 and the upper jaw 90 to the right as shown in FIG. 2, the movement of such jaws being guided by the supporting plates 102 which receive the upper jaw 90 therebetween. As the jaws 90 and 94 move to the right as appears in FIG. 2, the jaw 94 ultimately bumps against an abutment 114 which is fixedly attached to the rear plate 46. At the time the jaw 94 bumps against the abutment 114, the rightward motion of the clevis 110 is being continued by the air cylinder 108 and the continued motion of the clevis 110 causes the lower jaw 94 to rise upwardly, pivoting about the pin 104, with the result that the jaws 90 and 94 again seize the tape 84. As previously indicated, the leading end 100 of the tape 84 is restrained during the rightward movement of the clevis 110; and, accordingly, the jaws 90 and 94 slip with respect to the tape 84 during the rightward movement of the clevis 110. After the lower jaw 94 has engaged the abutment 114 and continued motion of the clevis 110 to the right has caused the lower jaw 94 to swing upwardly as described, the available rightward movement of the cylinder 108 is stalled, and the tape is thereby clamped between the jaws 90 and 94 by maintaining the force of cylinder 108 in the rightward direction.
For reasons to be more fully described in a later portion of this specification, a vertical tape knife 116 is attached to the tape press member 54 by a knife bracket 118. This knife, which moves with the press member 54, will be utilized to sever the tape 84 at an appropriate point in the operating cycle hereinafter described. There is also shown in the drawings, particularly FIGS. 1 and 2, an air cylinder 124 which is mounted to aforementioned bracket 21. The air cylinder 124 has an actuator rod 128 joined by a collar 126 to a tape ram 122. As will be more fully discussed in the operating cycle described below, the tape ram 122 is moved at appropriate times by operation of the air cylinder 124 for the purposes of advancing tape being wrapped about a coil end to desired positions.
In a preferred operating cycle, the initial position of the apparatus 20 is as shown in FIG. 2. The upper tape jaw 90 and lower tape jaw 94 are in their most rightward positions gripping the tape 84 at its then leading end 100. The adhesive side of the tape 84 is the side facing gripping portion 96. The stator core 26 is supported by the track 36 so that the coil end 22 is in a position ready for taping. Both the tool member 48 and the tape press member 54 are withdrawn away from the coil end 22 with the lower margin 62, lower extension 56, and their clamping surfaces 58 and 60 spaced apart to expose the window 50. The tape ram 122 is also withdrawn away from the stator core 26.
The jaws 90 and 94 are then advanced toward window 50 by the action of air cylinder 108 on lower jaw 94, with the jaws remaining in a closed and gripping position by the pivoting action of lower jaw 94 about the pin 104. The leading end 100 of the tape 84 is thereby inserted through the exposed window 50. The tool member 48 is then raised by actuation of air cylinder 78, causing the tape end to be clamped at window 50 between the clamping surface 58 on the lower extension 56 of the tape press member 54, and the clamping surface 60 on the lower margin 62 as shown in FIG. 4.
After the leading end 100 is clamped at the window 50, the lower jaw 94 pivots away from upper jaw 90 to release the tape, as shown in FIG. 5. The pivoting of the lower jaw 94 away from jaw 90 is accomplished by reversing air cylinder 108 to move the tape jaws 90 and 94 back to their rightward position. Air cylinder 108 causes clevis arm 110 to pull the lower jaw 94 pivotally about the pin 104 and thereby separate the lower jaw 94 from the upper jaw 90. The separation of the lower jaw 94 from the upper jaw 90 is only slight, however, since the pin 112 will strike the bracket 106 shortly after the pivoting action of the jaw 94 begins, as is shown in FIG. 5. The continued action of the pin 112 against the bracket 106 will then cause both upper jaw 90 and lower jaw 94 to move rightwardly toward their original positions.
As shown in FIG. 6, the lower and upper jaws will again grip the tape as they move rightwardly to their original positions. When lower jaw 94 strikes the abutment 114, its rightward movement is stopped, and the continued rightward action of air cylinder 108 causes the lower jaw 94 to pivot about pin 104 until the jaws 90 and 94 come to rest, clamping the tape 84.
The lower cylinder 80 is then actuated to move the tape press member 54 down against the corresponding surface portion of the radially outward side 30 of coil end 22 so that the contoured surface 64 of press member 54 presses the adhesive side of a section of the tape adjacent the leading end 100 against the coil end 22, as shown in FIG. 7. As the tape press member 54 moves down, the tape knife 116 severs the tape 84 at a trailing end portion 120 so that a predetermined length of tape is used to wrap the coil end 22. The downward movement of tape press member 54 will bend trailing end portion 120 into the path of tape ram 122. During this downward movement, air cylinder 80 and air cylinder 78 are acting against each other, the clamping surface 60 on lower margin 62 being urged by air cylinder 78 upward and against the clamping surface 58 on the lower extension 56, which is being pushed downward by air cylinder 80. In the preferred embodiment, air cylinders 78 and 80 have been so chosen that the force exerted by cylinder 80 will be greater than that exerted by cylinder 78. Thus, the downward force of air cylinder 80 is sufficient to overcome the upward force of air cylinder 78, resulting in the movement of both the tool member 48 and tape press member 54 downward. However, the action of air cylinder 78, even though overpowered by air cylinder 80, keeps the tool member 48 biased upward so that the tape 84 continues to be clamped at window 50 between the clamping surface 58 on lower extension 56 and the clamping surface 60 on the lower margin 62 of tool member 48.
After the tape is pressed against the coil end 22 by the surface 64, air cylinder 78 is reversely actuated in order to reverse the direction of force on tool member 48 so that clamping surface 60 on margin 62 moves down and away from clamping surface 58 on lower extension 56. Window 50 is again exposed for receiving tape, but this time adjacent the radially inward side 32 of the coil end 22. Tape ram 122 is then moved axially by air cylinder 124 toward the opened window 50, pushing the trailing end 120 around the inward side 32 of coil end 22 and through the window 50 as shown in FIG. 8. The tool member 48 is then moved upward by air cylinder 78, clamping the leading and trailing ends of the tape together between the clamping surfaces 58 and 60 on lower extension 56 and lower margin 62 as shown in FIG. 9. The tool member 48 and tape press member 54 are then both withdrawn upwardly from the stator core by air cylinders 78 and 80, drawing trailing end 120 tightly around the coil and leaving a tab 130 formed by the two tape ends extending upwardly between the coil end 22 and core 26 as shown in FIG. 10. The ram 122 is withdrawn by reversing air cylinder 124, the stator core 26 is removed, the tool member 48 and tape press member 54 are moved apart to expose the window 50, and the apparatus is again in the initial position shown in FIG. 2, ready to perform the taping operation on a new coil end.
As can be seen most clearly in FIGS. 10 and 11, the tab 130 is formed by the taping apparatus with trailing end 120 overlapping leading end 100 so that the adhesive side 132 of the tab faces the coil end and can be manually pressed against it. This arrangement has been found to be particularly helpful in the manufacture of stators. Frequently there are finish wires leading from the stator coil which need to be readily available for later electrical connections but which often interfere with other work operations to be performed on the stator if they are left dangling from the coil. If such is the case, the finish wires may be conveniently held in place against the coil end by bringing them around the coil end to a position adjacent the tab 130, and then pressing the tab 130 to the coil end and over the finish wires.
It should be noted that, although the adhesive side 132 of the tab is shown in FIG. 11 generally facing the coil end, it can, if desired, be alternately made to face the core so that the tab may be pressed against the core rather than the coil end. This reversal is accomplished by making the leading end 100 longer than the trailing end 120. The relative length of the leading and trailing ends and the overall length of the tab 130 is easily varied during the operation of the apparatus by either controlling the movement of the advancing mechanism 88 so that more or less tape is fed through the exposed window 50 at the beginning of the taping operation, and in so doing affecting the length of the leading end 100, or by changing the mounting of the knife 116, by spacers or the like (not shown), so that it cuts the tape closer to or farther from the window 50, and in so doing affecting the length of the trailing end 120.
In a second embodiment shown in FIGS. 12 through 17, the construction and operation of the taping apparatus may be modified so that no tab will be formed. For purposes of comparison, the letter "a" has been added to the reference numerals of the second embodiment, but otherwise the parts of the second embodiment have been designated with generally the same reference numbers as the corresponding parts of the first embodiment.
FIG. 12 shows the initial position of an elongate tool member 48a, a tape press member 54a, and a coil end 22a. The tool member 48a and the tape press member 54a are controlled by a dual air cylinder (not shown) corresponding to the air cylinder 66 of the preferred embodiment. The upper air cylinder of the dual air cylinder vertically moves the tool member 48a, and the lower air cylinder of the dual air cylinder vertically moves the tape press member 54a.
For purposes of illustrating the application of the present invention to coils of various shapes, the coil end 22a is illustrated as having a generally square shape with a surface 64a correspondingly contoured. A square-shaped coil is generally indicative of a free standing coil, i.e., a coil which is wound first and later inserted into a stator core. The actual shape of the coil end, however, is generally unimportant in the practice of either the first or second embodiments, and the present invention may be used in taping either a coil wound on a stator core or a coil wound and later inserted into a stator core. In a coil of the latter type, the taping in accordance with the present invention may be accomplished either prior to or after insertion of the coil into the stator core.
A leading end 100a of adhesive tape 84a is moved by a tape advancing mechanism (not shown) and inserted through a window 50a in tool member 48a. The previously mentioned upper air cylinder is actuated to raise tool member 48a and thereby clamp the leading end 100a between a lower margin 62a on tool member 48a and a lower extension 56a on tape press member 54a, at their clamping surfaces 58a and 60a. As shown in FIG. 13, the tool member 48a and tape press member 54a are moved down toward the coil end 22a. This downward movement is accomplished by the downward action on the lower air cylinder on tape press member 54a. As in the preferred embodiment, the tape remains clamped during the downward movement by biasing tool member 48a upwardly with the upper air cylinder.
When contact between the coil end and tape 84a is made, as illustrated in FIG. 14, the upper air cylinder is reversed so that the margin 62a on tool member 48a is moved away from the lower extension 56a on tape press member 54a. This single step is required to prevent the tape 84a from tearing, which would occur if the tool member 48a and the tape press member 54a continued their downward movement with the tape clamped therebetween.
Thereafter, the tool member 48a and the tape press member 54a continue their spaced apart and downward movement until they reach a position, shown in FIG. 15, at which the window 50a is exposed on the inward side 32a of the coil end, and the contoured surface 64a is in contact with the coil end so that a portion of the tape, including a leading end 100a, is pressed to the coil end, and a trailing end 120a is bent into the path of a tape ram. As illustrated in FIG. 16, the tape ram (not shown) then pushes the trailing end 120a of the tape through the window 50a. The tape press member 54a and tool member 48a are then moved upwardly by the dual air cylinder, with the clamping surfaces 58a and 60a remaining apart so that the lower margin 62a wraps the trailing end 120a of the tape around a back side 136a of the coil end, illustrated at the left side of the coil end in FIG. 17, over the leading end 100a of the tape.
Although the presently preferred embodiments of this invention have been described, it will be noted that within the purview of this invention various changes may be made within the scope of the appended claims. | Apparatus for wrapping tape around the end of a stator coil. The apparatus advances tape from a spool to a position near the coil end, where it is clamped by clamping members and cut, and a section of the tape adjacent the leading end is pressed against one side of the coil end. The trailing end of the tape is then pushed around the opposite side of the coil end where it is received by the clamping members. The trailing end is moved by the clamping members toward the leading end to draw the trailing end tightly around the coil and press it to the leading end. | 8 |
This is a divisional of application Ser. No. 08/987,981, filed Dec. 10, 1997, now U. S. Pat. No. 6,159,341.
BACKGROUND OF THE INVENTION
The present invention relates to a wire section of a fiber web forming machine, particularly a paper making machine for forming a multi-ply fiber web, particularly a paper web. The wire section includes a wire section belt of a paper machine on which a first fiber ply is formed. It includes a twin-wire part of the wire section designed as a gap former and having a first and a second wire in which part a second fiber ply is formed. The two wires wrap around a forming roll at the beginning of the twin wire part. It further includes a combining section, in which the first and the second fiber plies are combined, for forming the multi-ply fiber web.
The invention further relates to a process for forming a multi-ply fiber web, including the steps of forming a first fiber ply, forming a second fiber ply, and then combining the first fiber ply, which is running in on a belt, and the second fiber ply, which is running in on a first wire, in a combining section.
Such a wire section and a process of this type for forming a multi-ply fiber web are disclosed in DE 44 02 274 A1, equivalent to U.S. Patent No, 5,584,967. This known wire section comprises a conventional Fourdrinier unit for forming a first fiber ply on a belt in the form of a horizontal wire. A second fiber ply is formed by a twin-wire part arranged above the first belt. The first and second plies are couched together, forming a multi-ply fiber web, particularly a paper or board web. According to FIG. 5 of DE '274, the twin-wire part is designed as a gap former.
The twin-wire part for forming the second fiber ply has a headbox or flowbox, has an evacuated forming roll downstream of the headbox, has a so-called D part which typically dewaters the web through a wire by suction and also applies pressure pulses on the wire and has a second forming roll. The two wires of the twin-wire part are led approximately horizontally and counter to the running direction of the belt, between the first forming roll and the second forming roll.
In the outlet region of the second forming roll, the top wire is lifted off the second fiber ply, and the second fiber ply is led to the couch roll on the bottom wire, at an angle of about 80° to the first wire.
Another wire section for forming a multi-ply fiber web is disclosed in WO 92/01111. In this wire section too, a first fiber ply is brought up on a belt which is a wire belt that runs approximately horizontally. A twin-wire part for forming a second fiber ply is arranged above the belt. The twin-wire part for forming the second fiber ply has a headbox and a forming board arranged downstream of the headbox. The board has a multiplicity of forming foils, which form a convexly slightly curved running surface for the first and the second wires and which engage the wire to produce pressure pulses. A wiper is provided on the top side at the outlet of the forming board. The top wire is lifted off the second fiber web upstream of the entry region of a couch roll. The bottom wire wraps around the couch roll by about 120°. A guide roll is provided on the underside of the belt so that the belt and the first wire wrap around the couch roll by about 45°. In the wire section in WO 92/01111, dewatering of the second fiber ply takes place solely on account of the tensile stress of the wires acting on the forming board, by centrifugal forces and by the force of gravity.
It is not possible to achieve high running speeds using these known wire sections. In addition, the twin-wire part arranged above the Fourdrinier unit needs considerable space. It is particularly unfavorable that the twin-wire part is located above that part of the Fourdrinier unit in which the finally formed (but still moist) multi-ply fiber web runs, on the belt, in the direction toward the following treatment stations (e.g. wire suction roll, press section, etc.). The quality of the web is thereby impaired.
SUMMARY OF THE INVENTION
It is the object of the present invention to provide a wire section of a paper machine and a process for forming a multi-ply fiber web that is as compact as possible and a process for forming a multi-ply fiber web that is of as high a quality as possible at high speeds.
The invention concerns a wire section for forming a multi-ply fiber web.
The wire section includes a belt which advances a first fiber ply toward a couch roll defining a combining section. A twin wire part of the wire section includes first and second wires between which a second fiber ply is initially formed. The second wire separates from the first wire and then the first wire which is supporting the second fiber ply meets the belt supporting the first fiber ply at the couch roll of the combining section to form the multi-ply fiber web. The twin wire part is arranged upstream of the combining section along the running direction of the belt. The second fiber ply runs on the first wire into the combining section at an angle less than 90° with respect to the belt entering the combining section. A suction box or arrangement holds the second fiber ply to the first wire when the first and second wires separate.
The wire section mentioned at the beginning achieves this object by the inflow direction of the fiber suspension into the gap former substantially corresponding to the running direction of the belt and furthermore, by the twin-wire part being upstream of the combining section in the running direction of the belt and by the second fiber ply on the first wire of the twin wire part running into the combining section at an angle of less than 90° with respect to the belt.
The process mentioned at the beginning for forming a multi-ply fiber web achieves this object because the second fiber ply is formed at least predominantly in the running direction of the belt and in a region which lies upstream of the combining section in the running direction of the belt, and because the second fiber layer on the first wire runs into the combining section at an angle of less than 90° with respect to the belt.
By the measures described above, the belt as well as the first and the second wires in the web forming section run substantially in the same running direction. It is therefore not necessary for the running direction of the second fiber ply to be deflected so sharply as in prior art before being combined with the first fiber ply. This eliminates the risk of the web lifting off the wire on which the web is carried at a location in the region of the couch roll, particularly if a relatively large diameter couch roll is provided. The runability of the overall wire section is increased. Thus, the limitation of the speed that is necessary with known wire sections is avoided. The multi-ply fiber web can therefore be formed at much higher speeds than was possible previously.
In addition, the smaller deflection at a higher speed allows higher moisture content directly upstream of the combining section, which produces an improved ply bond strength.
Furthermore, as a result of the invention the second fiber ply is formed above the initial part of the Fourdrinier unit, that is, above, where the first fiber ply is located on the belt. This avoids the second ply being formed above the combined, multi-ply fiber web. The combined multi-ply fiber web is therefore not interfered with by the twin-wire part which forms the second fiber ply. Such interference, for example, may be by condensate droplets falling on the combined web. This improves the quality of the finished multi-ply web.
Finally, arranging the twin-wire part upstream of the combining section in the running direction of the belt provides more space for the arrangement of dewatering and suction elements in the initial part of the Fourdrinier unit, since the combining point can be located closer to a wire suction roll of the Fourdrinier unit, for example. This produces a particularly compact construction of the wire section according to the invention.
The belt for the first ply can be designed as a wire or as a felt.
Moreover, it has been shown that an entry angle range of less than 90° is particularly beneficial for achieving particularly high speeds and a compact construction. An entry angle range of between 60° and 80° is particularly preferred particularly in cooperation with the above-mentioned relative large diameter couch roll.
According to a further preferred embodiment, the twin-wire part may be a separate unit which is placed as a unit onto the Fourdrinier unit. This enables the twin-wire part of the wire section according to the invention to be used for retrofitting of existing wire sections.
The design of the twin-wire former as a gap former produces a very good transverse profile of the second fiber ply and also enables very quiet running, which may be summarized under the heading “very good stability”, Further advantages of using a forming roll as the first forming element after the headbox reside in a particularly insensitive jet injection and in secure guidance not only of the inner wire but also of the outer wire, without the risk of “wire piping”, which can cause longitudinal stripes in the finished paper. This risk exists when the first forming element is an only slightly curved forming board. There is a further advantage that, in spite of a relatively high consistency (about 1-1.5%), a finished paper web is produced which has very good “formation”, i.e., with uniform fiber distribution.
The forming roll may be evacuated or not evacuated. In both cases, this achieves particularly high initial dewatering in the region of the forming roll. As a result, the second fiber ply can be led along a short path to the combining section. This also produces a particularly compact construction.
An embodiment is advantageous in which the second fiber ply, which is initially dewatered on the forming roll, can be led to couch roll on a direct path, without deflection around a further roll. This permits particularly high operating speeds to be achieved. It is particularly beneficial to arrange the forming roll underneath the “gap”, i.e., the entry pocket of the wires into the twin-wire zone. In this case, the forming roll may preferably not be evacuated but is nevertheless provided with an open surface, for the temporary storage of water. As a result, the second fiber ply is dewatered with less damage on the forming roll side so that fines are kept in this side of the paper ply. Since it is only this side of the second fiber ply that contacts the first fiber ply, the bonding of the fiber plies is improved.
In this case, providing a dewatering arrangement between the forming roll and the couch roll is particularly preferred. That arrangement has a box, preferably a suction box that is assigned to the first wire, designated as a top wire. The suction box includes stationary forming foils which are located in the loop of and engage the first wire and which generate pressure pulses in the suspension. Forming foils may also contact the second wire designated as a bottom wire. The foils of the first wire form a convexly curved running surface which deflects the second wire through an angle in the range of 0° to 20°. The foils above and below are arranged to alternate in the wire running direction. The forming foils can be designed to be movable or to be rigid.
This type of dewatering arrangement is also known as a D part. Connecting such a D part downstream of a forming roll that produces the initial dewatering causes ideal web formation. The formation of flocs is largely prevented. The result is shear forces acting uniformly over the web thickness. In this case, it is of particular advantage if the stationary forming foils form a concavely curved running surface by means of which the top wire is deflected through an angle in the range from 0° to 20°.
This means retains both wires securely in contact with the second fiber ply being formed which produces more uniform dewatering in the region of the dewatering arrangement, i.e., the D part. Deflection at an angle in the range from 0° to 20° is, on the other hand, still acceptable in this case from the point of view of maximum speed.
According to a further preferred embodiment, the first wire is designed as a top wire and wraps around the forming roll, while the first and the second wires together wrap around a deflection roll between the forming roll and the combining section. This variant is particularly advantageous when an especially thick and therefore initially high water content second fiber ply and/or an especially difficult to dewater second fiber ply is intended to be formed. The achievable speeds are not quite as high as in the previous embodiment which is without a deflection roll between the forming roll and the combining section. Alternatively, the deflection roll can be designed as an evacuated or a non-evacuated forming roll.
In an embodiment wherein the second wire has a series of forming foils applied against it, the foils are arranged opposite a region of the forming roll which is wrapped around by the top wire and the bottom wire. This improves formation on that side of the second fiber ply, which is joined to the first fiber ply in the combining section. The forming foils can be designed both as rigid foils and also as movable forming foils.
A suction separator is assigned to the first wire upstream of the couch roll. The suction separator enables the bottom wire to be separated from the second fiber ply at high running speed, before the second fiber ply is carried on the top wire to the combining section.
Of course, the present invention can be used for producing two-ply fiber webs and also three-ply or multi-ply fiber webs.
Further, the features described above and features explained below can be used not only in the combinations specified but also in other combinations or on their own, within the scope of the invention.
Other features and advantages of the present invention will become apparent from the following description of the invention which refers to the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 schematically shows a wire section for producing a multi-ply fiber web, including a twin-wire part placed on a Fourdrinier unit;
FIG. 2 shows a schematic side view of a first embodiment of a twin-wire part according to the invention; and
FIG. 3 shows a schematic side view of a second embodiment of a twin-wire part according to the invention.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a first embodiment of a wire section 9 according to the invention, which is used for forming multi-ply fiber webs, in particular paper or board webs. The wire section 9 is therefore predominantly intended for papermaking machines.
The wire section comprises a Fourdrinier unit 6 , having an approximately horizontally guided belt (preferably a web or a felt) 12 , with a running direction shown by an arrow 14 . On the belt 12 , a first fiber ply (not illustrated) is formed by a headbox or flowbox 8 followed by a plurality of dewatering elements 7 . As explained below, the first fiber ply is combined with a second fiber ply to form a two-ply fiber web.
A twin-wire part 20 , shown enlarged in FIG. 2, is arranged above the belt 12 and forms the second fiber web or ply. The twin-wire part 20 has a first endless loop belt or wire 22 and a second endless loop belt or wire 24 , which are guided to move parallel through a twin-wire zone in order to form the second fiber ply. In the region of the beginning of the twin-wire zone, the two wires 22 , 24 form an entry gap 28 . A headbox 26 indicated schematically at the entry gap 28 injects a fibrous suspension for the second fiber ply into the entry gap 28 . Alternatively, a multi-layer headbox can also be provided. This type of arrangement causes the twin-wire part 20 to be a so-called “gap former”,
A forming roll 30 is provided in the region of the entry gap 28 and in the loop of the second wire 24 , which is a bottom wire. A wire guide roll 32 is provided in the loop of the first wire 22 , which is a top wire.
The forming roll 30 has an open roll cover, i.e., it is provided with cutouts, and it is preferably not an evacuated roll. Alternatively, the forming roll 30 may be evacuated. The wires 22 , 24 run together over an upper section of the forming roll 30 and between the roll 30 and the opposite wire guide roll 32 . The wires wrap around the forming roll 30 over an angle which is preferably smaller than 90°.
Directly adjoining the forming roll 30 is a web dewatering section 39 in the form of a so-called D part. In the region of the top wire 22 , the D-part includes an either evacuated or non-evacuated suction box 36 which supports a series of stationary forming foils or strips 34 which are oriented so that their free ends contact and press against the top wire. The suction box 36 is combined with a suction separator. The first stationary foil 34 of the suction box 36 is arranged directly in the outlet region of the forming roll 30 . The forming foils 34 of the box 36 together form a running surface that is slightly convexly curved in the running direction of the wires 22 , 24 . On the side of the bottom wire 24 , opposite the foils 34 of the box 36 , a number of movable, preferably pneumatically loaded foils or strips or ledges may be arranged. The movable foils or strips have free ends or edges that are oriented to press against the bottom wire 24 . The stationary foils 34 and the movable foils of the forming board 38 are arranged to alternate along the wire running direction.
There are water receiving containers 37 and 39 , respectively, associated with the foils 34 and 38 .
In the outlet region of the D part 39 , the bottom wire 24 is separated from the second fiber ply by a suction separator 62 . The bottom wire is led back to the forming roll 30 over a plurality of guide rolls 40 .
The top wire 22 with the formed second fiber ply carried on it is led directly from the outlet region of the D part to a couch roll 42 . The diameter d of the couch roll 42 is relatively large, e.g. as large as or only slightly smaller than the diameter D of the forming roll 30 . The couch roll 42 is arranged such that the couch roll 42 dips into the belt, or such that the roll is slightly wrapped around by the belt 12 .
The top wire 22 carrying the second fiber ply runs from the D part 39 , oriented at an angle 44 of less than 90°, preferably in the range of 70° to 80°, and shown herein at about 75° with respect to the belt 12 and onto the couch roll 42 . The first and the second fiber webs are couched together between the top wire 22 and the belt 12 by means of the couch roll 42 . The top wire 22 is separated from the multi-ply fiber web in the outlet region of the couch roll 42 . The multi-ply fiber web that is combined in this way to consist of the first and the second fiber plies is separated from the top wire 22 by a further suction separator 63 and thereafter runs further together with the belt 12 , for example over a suction box 64 and a wire suction roll 65 (FIG. 1 ). The web is thereafter removed from the belt 12 in a known way, by a felt belt 66 and a pickup roll 67 , and is fed to a following unit of the machine, e.g. a press section. The top wire 22 is led back to the wire guide roll 32 located opposite the forming roll 30 by wrapping over wire guide rolls 46 .
Thus, for the purpose of initial dewatering, the twin-wire part 20 has a forming roll 30 followed by a so-called D part 39 for further dewatering. The twin-wire part 20 is therefore a so-called “roll-blade former”.
In this embodiment, the twin-wire part 20 is arranged upstream of the couch roll 42 along the running direction 14 of the belt 12 . Arrangement upstream of the couch roll 42 means that the forming or wire section from the headbox 26 and including the last forming unit (D part 39 ) is arranged upstream of the couch roll 42 . That the wire guide rolls 46 for return travel of the empty top wire 22 are to some extent placed downstream of the couch roll 42 as viewed on the path of the belt 12 , as shown in FIG. 2, is intended to be irrelevant in the present context.
This arrangement causes the two wires 22 , 24 of the twin-wire part 20 and the belt 12 to have substantially the same running direction. Therefore, the second fiber ply in the twin-wire former 20 is deflected only slightly before being couched. This enables extraordinarily high speeds of the entire wire section 9 to be achieved.
This arrangement of the forming roll 30 and the downstream D part 39 in the twin-wire part 20 produces a side of the second fiber ply that is richer in fines on the side facing away from the top wire 22 , and that is the side of the second ply that is couched together with the top side of the first fiber ply.
Other arrangements of forming foils are also possible instead of the D part 39 . For example, a suction box may also be provided on the bottom wire. Also, the forming roll 30 could also be evacuated. However, it has been found that extraordinarily high speeds with an excellent quality of the multi-ply fiber web formed can be achieved as a result of the combination of a non-evacuated open forming roll 30 with a D part 39 .
FIG. 3 illustrates a second embodiment 50 of a twin-wire part according to the invention. The same reference numbers are used for elements which have the same function as corresponding elements of the twin-wire part 20 .
The twin-wire part 50 again has an approximately horizontally aligned belt 12 , on which a first, performed fiber ply leads to the twin-wire part 50 in the direction 14 .
The twin-wire part 50 has a top wire 22 and a bottom wire 24 . The twin-wire part 50 has a forming roll 52 , which is wrapped around by the top wire 22 . A wire guide roll 54 is provided on the bottom wire 24 in the region of the entry gap 28 and the bottom wire 24 runs from the wire guide roll 54 onto the forming roll 52 . The forming roll 52 has an arcuate suction section 56 , which is arranged approximately in the region over which the top wire 22 and the bottom wire 24 together wrap around the forming roll 52 . A series of forming foils 58 are provided on the bottom wire 24 opposite the forming roll 52 and their free ends press on the wire 24 . These foils 58 are movable. Each foil 58 is pneumatically pressed, i.e., compliantly, against the bottom wire 24 with an individually adjustable force.
The top wire 22 and the bottom wire 24 , together with the second fiber ply that is arranged between them but is not illustrated, run obliquely upward from the forming roll 52 and wrap around a deflection roll 60 . From the deflection roll 60 , the top wire 22 , with the second fiber web ply lying upon it, runs to the couch roll 42 . In order to lift the second ply off the bottom wire 24 , a suction separator 62 is arranged on the side of the top wire, just downstream of the outlet region of the deflection roll 60 . The web is carried on the underside of the upper wire 22 . From the suction separator 62 , the top wire 22 , together with the fiber ply lying upon it, runs onto the couch roll 42 at an angle 44 of about 75° in relation to the belt 12 . At the belt 12 , the first fiber ply on the belt 12 meets the second fiber ply on the wire 22 . A catching container 41 is located underneath the bottom wire for receiving spray water. One of these containers may also be provided in the embodiment of FIG. 2 .
The twin-wire part 50 differs from the twin-wire part 20 illustrated in FIG. 2, first by the arrangement of the forming elements, i.e., forming roll 52 and forming foils 58 , and secondly by the deflection roll 60 , which is provided between the forming roll 52 and the couch roll 42 . The deflection roll 60 can either be an evacuated or a non-evacuated forming roll.
In this embodiment also, the second fiber ply is deflected only slightly before running into the couch roll 42 . This is because, in contrast with the twin-wire part 20 , the forming roll 52 of the twin-wire part 50 is wrapped around by the wires 22 , 24 only over a relatively small angular section of about 45°, whereas the forming roll 30 of the twin-wire part 20 is wrapped around by the wires 22 , 24 over an angle of about 90°.
The twin-wire parts 20 and 50 have in common that their twin-wire zones are both arranged upstream of the couch roll 42 in the running direction 14 of the belt 12 . As a result, the second fiber ply must be deflected only slightly, proceeding from the headbox 26 as far as the couch roll 42 . This applies especially as the running direction 14 of the belt 12 and that of the wires 22 , 24 in their forming region, i.e., their twin-wire zones, are substantially identical. In other words, the outflow directions of the two headboxes 8 and 26 in FIG. 1 are at least approximately identical. This means, coupled with the compact construction of the twin-wire part, enables the distance A between the couch roll 42 and the wire suction roll 65 to be made smaller than previously. This means that a small overall length of the wire part 9 can be achieved.
The slight deflection of the second fiber ply in the twin-wire parts 20 and 50 enables very high operating speeds to be achieved with the wire sections 9 according to the invention, without a risk of the web lifting off. At the same high speed, the lower deflection allows higher moisture contents directly upstream of the couching stage, which achieves an improved ply bond strength. Since both twin-wire parts 20 , 50 are upstream of the couch roll 42 in the running direction 14 of the belt 12 , the jointly couched multiply fiber layer following the couch roll 42 is not influenced by the operation of the twin-wire part 20 , 50 . In particular, condensate droplets do not drop from the twin-wire part 20 , 50 onto the finished multi-ply fiber layer. In any case, such droplets would impinge on the performed first fiber ply. But, this would not significantly impair the web formation.
The twin-wire parts 20 , 50 are preferably used for forming a white liner on the first fiber ply or for increasing the basis weight.
Although the present invention has been described in relation to particular embodiments thereof, many other variations and modifications and other uses will become apparent to those skilled in the art. It is preferred, therefore, that the present invention be limited not by the specific disclosure herein, but only by the appended claims. | A wire section for forming a multi-ply fiber web. The wire section includes a first belt which advances a first fiber ply toward a couch roll defining a combining section. A twin-wire zone of the wire section includes first and second wires between which a second fiber ply is initially formed in a gap former. The second wire separates from the first wire and then the first wire supporting the second fiber ply meets the first belt supporting the first fiber ply at the couch roll of the combining section to form the multi-ply fiber web. The twin-wire part is arranged upstream of the combining section along the running direction of the first belt. The second fiber ply runs on the first wire into the combining section at an angle less than 90° with respect to the belt entering the combining section. The path of the wires from the forming roll to the combining section is disclosed. A suction box or arrangement holds the second fiber ply to the first wire when the first and second wires separate. Dewatering foils press on the wires moving through the twin-wire zone. | 3 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority to and the benefit of U.S. Provisional Patent Application No. 61/769,548, filed 26 Feb. 2013, the disclosure of which is now expressly incorporated herein by reference.
TECHNICAL FIELD
[0002] The present disclosure relates to aircraft, engines, and particle separators for aircraft and engines.
BACKGROUND
[0003] Particle separators that effectively remove particles from an airflow to provide relatively clean air to an engine remain an area of interest. Some existing systems have various shortcomings, drawbacks, and disadvantages relative to certain applications. Accordingly, there remains a need for further contributions in this area of technology.
SUMMARY
[0004] One embodiment of the present disclosure is a unique particle separator. Another embodiment is a unique aircraft. Another embodiment is a unique inertial particle separator. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for aircraft, engines and particle separators for aircraft and engines. Further embodiments, forms, features, aspects, benefits, and advantages of the present application will become apparent from the description and figures provided herewith.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] The description herein makes reference to the accompanying drawings wherein like reference numerals refer to like parts throughout the several views, and wherein:
[0006] FIG. 1 schematically illustrates some aspects of a non-limiting example of an aircraft in accordance with an embodiment of the present disclosure;
[0007] FIG. 2 schematically illustrates a sectional view of some aspects of a non-limiting example of a particle separator in accordance with an embodiment of the present disclosure;
[0008] FIG. 3 schematically illustrates an isometric view of some aspects of a non-limiting example of a particle separator in accordance with an embodiment of the present disclosure; and
[0009] FIGS. 4A-4C illustrate some particle trajectories for an embodiment of a particle separator in accordance with the present disclosure.
DETAILED DESCRIPTION
[0010] For purposes of promoting an understanding of the principles of the disclosure, reference will now be made to the embodiments illustrated in the drawings, and specific language will be used to describe the same. It will nonetheless be understood that no limitation of the scope of the disclosure is intended by the illustration and description of certain embodiments of the disclosure. In addition, any alterations and/or modifications of the illustrated and/or described embodiment(s) are contemplated as being within the scope of the present disclosure. Further, any other applications of the principles of the disclosure, as illustrated and/or described herein, as would normally occur to one skilled in the art to which the disclosure pertains, are contemplated as being within the scope of the present disclosure.
[0011] Referring to FIG. 1 , some aspects of a non-limiting example of an aircraft 10 in accordance with an embodiment of the present disclosure are schematically depicted. Aircraft 10 includes a flight structure 12 , an air inlet 14 , a particle separator 16 , a transition duct 18 , an engine 20 , an exhaust nozzle 22 , and an exhaust exit 24 . In one form, aircraft 10 is a fixed-wing aircraft. In other embodiments, aircraft 10 may be a rotary wing aircraft or any other type of aircraft. In one form, flight structure 12 is a wing structure of aircraft 10 . In other embodiments, flight structure 12 may be a fuselage, a lift body, an empennage and/or any other structure of an aircraft. In one form, air inlet 14 and exhaust exit 24 are disposed on an upper surface of flight structure 12 . In other embodiments, one or both of air inlet 14 and exhaust exit 24 may be disposed on, embedded in or otherwise attached to or extending from any portion of flight structure 12 .
[0012] In one form, air inlet 14 is louvered. In other embodiments, air inlet 14 may take any other form. In one form, particle separator 16 is fluidly disposed downstream of air inlet 14 . In other embodiments, particle separator 16 may form part or all of air inlet 14 . In one form, particle separator 16 is displaced from the inlet of engine 20 , and is in fluid communication with the inlet of engine 20 via transition duct 18 . In other embodiments, particle separator 1 $ may be disposed immediately adjacent to the inlet of engine 20 . Particle separator 16 is configured to remove particles within a selected size or mass range from air received via air inlet 14 for use by engine 20 , e.g., in providing propulsion or other power for aircraft 10 . Transition duct 18 is configured to provide the cleaned air output of particle separator 16 to engine 20 . In one form, engine 20 is a gas turbine engine. In other embodiments, engine 20 may be another type of engine. In the form, as a gas turbine engine, engine 20 is a turbofan engine. In other embodiments, engine 20 may be any other type of gas turbine engine, e.g., a turbojet engine, a turboshaft engine, a turboprop engine, a hybrid engine, or may be any other type of turbomachine engine, including, for example, a pulse-jet, pulse detonation, ramjet, scramjet or any other type of subsonic, sonic, supersonic or hypersonic engine.
[0013] Referring to FIGS. 2 and 3 , some aspects of a non-limiting example of particle separator 16 are illustrated in accordance with an embodiment of the present disclosure. Particle separator 16 is an inertial particle separator. In one form, particle separator 16 includes a plurality of linear flow splitters 30 , structures in the form of linear end-wall flow guides 32 , a plurality of shaped linear flow splitters 34 , a plurality of linear flow splitters 36 , and a plurality of linear scavenge flowpaths or passages 38 . Flow splitters 30 , 34 and 36 ; flow guides 32 and scavenge flowpaths 38 are referred to as “linear” because they are not bodies of revolution disposed about a centerline, but rather, extend generally linearly between side or end 40 and side or end 42 . In one form, flow splitters 30 , 34 and 36 ; flow guides 32 ; and scavenge flowpaths 38 extend in a straight line between ends 40 and 42 , e.g., as would an extruded shape. In other embodiments, flow splitters 30 , 34 and 36 ; flow guides 32 ; and scavenge flowpaths 38 may not extend in a straight line, and may, for example and without limitation, undulate between ends 40 and 42 or otherwise vary from a straight line between ends 40 and 42 . In one form, each of flow splitters 30 , 34 and 36 ; flow guides 32 ; and scavenge flowpaths 38 are formed of sheet aluminum. In other embodiments, other materials may be employed. In the depicted embodiment, a sheet thickness of 0.055 inches is employed. In other embodiments, the material thickness may vary with the needs of the application.
[0014] Each flow splitter 30 is disposed adjacent to another flow splitter 30 or to one of flow guides 32 . Formed between adjacent flow splitters and/or flow guides 32 are flowpaths 44 . In some embodiments, only a single flow splitter 30 may be employed, e.g., disposed between flow guides 32 , and form two flowpaths 44 . Other embodiments may not employ any flow splitters 30 , and may form a single flowpath 44 between flow guides 32 . Still other embodiments may employ any number of flow splitters 30 , forming (in conjunction with flow guides 32 ) any number of flowpaths 44 .
[0015] In one form, flow splitters 34 are disposed downstream of flow splitters 30 and flow guides 32 , i.e., downstream of the leading edge portions 46 of flow splitters 30 and flow guides 32 . In other embodiments, flow splitters 34 may not be positioned downstream of flow splitters 30 and flow guides 32 . Flow splitters 34 are configured to subdivide each flowpath 44 into two flowpaths 48 . In one form, each flowpath 48 has the same flow area. In other embodiments, the flow area may vary between instances of flowpaths 48 . In one form, flow splitters 36 are disposed downstream of flow splitters 34 , i.e., downstream of the leading edge portions 49 of flow splitters 34 . In other embodiments, flow splitters 36 may not be disposed downstream of flow splitters 34 . Flow splitters 36 are configured to subdivide each flowpath 48 into two flowpaths, a vitiated air flowpath 50 and a cleaned air flowpath 52 . Each vitiated air flowpath 50 culminates in a scavenge flowpath 38 . In one form, scavenge flowpaths 38 are perpendicular to vitiated air flowpath 50 , e.g., perpendicular to the plane of the drawing of FIG. 2 . In other embodiments, scavenge flowpaths 38 may be arranged at other angles. Scavenge flowpaths 38 are configured to receive particles captured in vitiated air flowpaths 50 . In one form, scavenge flowpaths 38 are configured to discharge the particles to a desired location, e.g., overboard aircraft 10 , e.g., via exhaust exit 24 . In some embodiments, a scavenge blower (not shown), ejector (not shown) or other device or system may be employed to apply a suction to scavenge flowpaths 38 , e.g., in order to assist removal of particles captured in vitiated air flowpaths 50 . In other embodiments, no suction may be applied to scavenge flowpaths 38 .
[0016] Flow splitters 34 are configured to impart an outward velocity (outward relative to flow splitters 34 ) to particles entrained in the air received into flowpaths 48 and to impart momentum to the particles in the air flow and direct at least some of the particles (with air) toward vitiated air flowpath 50 . In one form, flow splitters 34 are configured to impart momentum to particles above a predetermined mass and direct the particles above the predetermined mass (with air) into vitiated air flowpath 50 , whereas the balance of the air is a cleaned air flow directed into cleaned air flowpath 52 along with some particles having a mass lower than the predetermined mass. The mass of particles (if any) entering cleaned air flowpath 52 is less than the mass of particles entering vitiated air flowpath 50 .
[0017] Walls 54 , 56 forming scavenge flowpaths 38 define a plurality of linear flow mixers 58 . Flow mixers 58 are positioned downstream of flow splitters 36 . Flow mixers 58 are configured to combine each adjacent pair of clean air flowpaths 52 into a single flowpath 60 . Flowpaths 60 are configured to direct the cleaned air toward the inlet of engine 20 .
[0018] Referring to FIGS. 4A-4C in conjunction with FIGS. 2 and 3 , during operation, air flow enters particle separator 16 approximately in the direction indicated by lines 70 . The airflow is split and directed into flowpaths 44 by splitters 30 and flow guides 32 . The air flow in each flowpath 44 is then split and directed into flowpaths 48 by flow splitters 34 . The airflow in each flowpath 48 is then split and directed into vitiated air flowpath 50 and clean air flowpath 52 . Adjacent pairs of clean air flowpaths 52 are combined by flow mixers 58 into flowpaths 60 . The vitiated air received into vitiated air flowpaths 50 flows into scavenge flowpaths 38 for removal from particle separator 16 .
[0019] In order to direct most or all of any particles in the air received into particle separator 16 into vitiated air flowpaths 50 , flow splitters 34 have a shape configured to impart momentum to particles in the air flowing in flowpaths 48 to direct the particles toward vitiated air flowpaths 50 , in addition, the flowpath walls 62 of flowpaths 48 , e.g., defined at least in part by flow splitters 30 , have a shape configured to direct the particles toward vitiated air flowpaths 50 . The path of the particles varies with the size (mass) of the particles. The shapes of flow splitters 34 and flowpaths walls 62 may vary with the needs of the application in order to direct particles within the selected mass range into vitiated air flowpaths 50 .
[0020] FIG. 4A-4C are analytical results illustrating the calculated trajectories of particles of different masses as they pass through illustrated portions of a non-limiting example of a particle separator 16 in accordance with an embodiment of the present disclosure. FIG. 4A illustrates streams 64 of ultra fine particles passing through the illustrated portions of particle separator 16 . FIG. 4B illustrates streams 66 of fine particles passing through the illustrated portions of particle separator 16 , wherein the shape of flow splitters 34 and walls 62 are configured to deflect the fine particles impacting flow splitters 34 and walls 62 toward vitiated air flowpath 50 . FIG. 4C illustrates streams 68 of course particles passing through the illustrated portions of particle separator 16 , wherein the shape of flow splitters 34 and wails 62 are configured to deflect the course particles impacting flow splitters 34 and walls 62 toward vitiated air flowpath 50 . The operating conditions for the illustration of FIGS, 4 A- 4 C are an engine 20 take-off power rating at sea level static, standard day inlet conditions. In the non-limiting example illustrated in FIGS. 4A-4C , flow splitters 34 and walls 62 are configured, e.g., in shape and elasticity, to direct substantially all of the fine and course particles into vitiated air flowpath 50 , e.g. as illustrated by particle streams 66 and 68 , respectively, entering vitiated air flowpath 50 ; and configured to direct most of the ultra fine particles into vitiated air flowpath 50 , e.g. as illustrated by particle streams 64 , at the same engine and inlet conditions. Hence, particle separator 16 is configured to provide relatively clean air to engine 20 via flowpaths 52 and 60 in the presence of ultra fine, fine and/or coarse particles in the air received into inlet 14 . Other engine power and/or inlet conditions may yield different particle capture results. In the illustrated examples of FIGS. 4A-4C , ultra fine particles are approximately 2 micron; fine particles are approximately 24 micron, and coarse particles are approximately 500 micron. Various embodiments of particle separator 16 may be configured to direct particles of other desired sizes and/or ranges of sizes into desired vitiated air flowpaths 50 . Also, in other embodiments, flow splitters 34 and walls 62 may be configured to yield different trajectories for particles of different sizes and/or masses in order to achieve the same or different results, e.g., different degrees of particle capture into vitiated air flowpaths 50 under the same or different engine and inlet conditions.
[0021] Embodiments of the present disclosure include a particle separator, comprising: two adjacent first linear flow splitters configured to form a first flowpath therebetween; a second linear flow splitter configured to subdivide the first flowpath into two second flowpaths; and two third linear flow splitters, each third linear flow splitter being configured to subdivide each second flowpath into -a pair of third flowpaths.
[0022] In a refinement, the particle separator further comprises a linear flow mixer configured to combine one third flowpath from each of two pairs of third flowpaths into a single fourth flowpath.
[0023] In another refinement, the fourth flowpath is configured to direct air toward a gas turbine engine.
[0024] In yet another refinement, the second linear flow splitter is positioned downstream of the first linear flow splitters; wherein the third linear flow splitters are positioned downstream of the second linear flow splitter; and wherein the linear flow mixer is positioned downstream of the third linear flow splitters.
[0025] In still another refinement, one of the third flowpaths formed by one of the third linear flow splitters is a vitiated air flowpath configured to receive a vitiated air flow wherein the other of the third flowpaths formed by the one of the third linear flow splitters is a clean air flowpath configured to receive a cleaned air flow.
[0026] In yet still another refinement, a mass of particles entering the clean air flowpath is less than a mass of particles entering the vitiated air flowpath.
[0027] In a further refinement, the second linear flow splitter is configured to impart momentum to particles above a predetermined mass and direct the particles with air toward the vitiated air flowpath.
[0028] In a yet further refinement, the balance of the air is directed into the clean air flowpath.
[0029] In a still further refinement, each of the second flowpaths have a same flow area.
[0030] In a yet still further refinement, the particle separator further comprises a scavenge flowpath in fluid communication with each vitiated air flowpath.
[0031] In another refinement, the scavenge flowpath is perpendicular to the vitiated air flowpath.
[0032] Embodiments of the present disclosure include an aircraft, comprising: a flight structure; an engine coupled to the flight structure; and a particle separator in fluid communication with the engine, including: one or more structures forming a first flowpath; a first linear flow splitter configured to subdivide the first flowpath into two second flowpaths; and two second linear flow splitters, each second linear flow splitter being configured to subdivide each second flowpath into a pair of third flowpaths.
[0033] In a refinement, the particle separator further includes a flow mixer configured to combine one third flowpath from each of two pairs of third flowpaths into a single fourth flowpath.
[0034] In another refinement, one of the third flowpaths formed by one of the second linear flow splitters is a vitiated air flowpath configured to receive a vitiated air flow; and wherein the other of the third flowpaths formed by the one of the second linear flow splitters is a clean air flowpath configured to receive a cleaned air flow.
[0035] In yet another refinement, a mass of particles entering the clean air flowpath is less than a mass of particles entering the vitiated air flowpath.
[0036] In still another refinement, the second linear flow splitter is configured to impart momentum to particles above a predetermined mass and to direct the particles with air toward the vitiated air flowpath.
[0037] In yet still another refinement, the balance of the air is directed into the clean air flowpath.
[0038] In a further refinement, the particle separator further includes a scavenge flowpath in fluid communication with each vitiated air flowpath. In a yet further refinement, the scavenge flowpath is perpendicular to the vitiated air flowpath.
[0039] Embodiments of the present disclosure include an inertial particle separator, comprising: means for forming a first flowpath; means for subdividing the first flowpath into a plurality of second flowpaths; and means for subdividing each second flowpath into a plurality of third flowpaths. In a refinement, the inertial particle separator further comprises means for combining at least some of the third flowpaths into a fourth flowpath.
[0040] While the invention has been described in connection with what is presently considered to be the most practical and preferred embodiment, it is to be understood that the disclosure is not to be limited to the disclosed embodiment(s), but on the contrary, is intended to cover various modifications and equivalent arrangements included within the spirit and scope of the appended claims, which scope is to be accorded the broadest interpretation so as to encompass all such modifications and equivalent structures as permitted under the law. Furthermore it should be understood that while the use of the word preferable, preferably, or preferred in the description above indicates that feature so described may be more desirable, it nonetheless may not be necessary and any embodiment lacking the same may be contemplated as within the scope of the disclosure, that scope being defined by the claims that follow. In reading the claims it is intended that when words such as “a,” “an,” “at least one” and “at least a portion” are used, there is no intention to limit the claim to only one item unless specifically stated to the contrary in the claim. Further, when the language “at least a portion” and/or “a portion” is used the item may include a portion and/or the entire item unless specifically stated to the contrary. | One embodiment of the present disclosure is a unique particle separator. Another embodiment is a unique aircraft. Another embodiment is a unique inertial particle separator. Other embodiments include apparatuses, systems, devices, hardware, methods, and combinations for aircraft, engines and particle separators for aircraft and engines. Further embodiments, forms, features, aspects, benefits, and advantages of the present disclosure will become apparent from the description and figures provided herewith. | 8 |
BACKGROUND OF THE INVENTION
The present invention relates to a new and distinctive corn inbred line, designated LH169.
The goal of plant breeding is to combine in a single variety/hybrid various desirable traits. For field crops, these traits may include resistance to diseases and insects, tolerance to heat and drought, reducing the time to crop maturity, greater yield, and better agronomic quality. With mechanical harvesting of many crops, uniformity of plant characteristics such as germination and stand establishment, growth rate, maturity, and fruit size is important.
There are numerous steps in the development of any novel, desirable plant germplasm. Plant breeding begins with the analysis and definition of problems and weaknesses of the current germplasm, the establishment of program goals, and the definition of specific breeding objectives. The next step is selection of germplasm that possess the traits to meet the program goals. The goal is to combine in a single variety or hybrid an improved combination of desirable traits from the parental germplasm. These important traits may include higher yield, resistance to diseases and insects, better stalks and roots, tolerance to drought and heat, and better agronomic quality.
Choice of breeding or selection methods depends on the mode of plant reproduction, the heritability of the trait(s) being improved, and the type of cultivar used commercially (e.g., F 1 hybrid cultivar, pureline cultivar, etc.). For highly heritable traits, a choice of superior individual plants evaluated at a single location will be effective, whereas for traits with low heritability, selection should be based on mean values obtained from replicated evaluations of families of related plants. Popular selection methods commonly include pedigree selection, modified pedigree selection, mass selection, and recurrent selection.
The complexity of inheritance influences choice of the breeding method. Backcross breeding is used to transfer one or a few favorable genes for a highly heritable trait into a desirable cultivar. This approach has been used extensively for breeding disease-resistant cultivars. Various recurrent selection techniques are used to improve quantitatively inherited traits controlled by numerous genes. The use of recurrent selection in self-pollinating crops depends on the ease of pollination, the frequency of successful hybrids from each pollination, and the number of hybrid offspring from each successful cross.
Each breeding program should include a periodic, objective evaluation of the efficiency of the breeding procedure. Evaluation criteria vary depending on the goal and objectives, but should include gain from selection per year based on comparisons to an appropriate standard, overall value of the advanced breeding lines, and number of successful cultivars produced per unit of input (e.g., per year, per dollar expended, etc.).
Promising advanced breeding lines are thoroughly tested and compared to appropriate standards in environments representative of the commercial target area(s) for three years at least. The best lines are candidates for new commercial cultivars; those still deficient in a few traits are used as parents to produce new populations for further selection.
These processes, which lead to the final step of marketing and distribution, usually take from eight to 12 years from the time the first cross is made. Therefore, development of new cultivars is a time-consuming process that requires precise forward planning, efficient use of resources, and a minimum of changes in direction.
A most difficult task is the identification of individuals that are genetically superior, because for most traits the true genotypic value is masked by other confounding plant traits or environmental factors. One method of identifying a superior plant is to observe its performance relative to other experimental plants and to a widely grown standard cultivar. If a single observation is inconclusive, replicated observations provide a better estimate of its genetic worth.
The goal of corn breeding is to develop new, unique and superior corn inbred lines and hybrids. The breeder initially selects and crosses two or more parental lines, followed by repeated selfing and selection, producing many new genetic combinations. The breeder can theoretically generate billions of different genetic combinations via crossing, selfing and mutations. The breeder has no direct control at the cellular level. Therefore, two breeders will never develop the same line, or even very similar lines, having the same corn traits.
Each year, the plant breeder selects the germplasm to advance to the next generation. This germplasm is grown under unique and different geographical, climatic and soil conditions, and further selections are then made, during and at the end of the growing season. The inbred lines which are developed are unpredictable. This unpredictability is because the breeder's selection occurs in unique environments, with no control at the DNA level (using conventional breeding procedures), and with millions of different possible genetic combinations being generated. A breeder of ordinary skill in the art cannot predict the final resulting lines he develops, except possibly in a very gross and general fashion. The same breeder cannot produce the same line twice by using the exact same original parents and the same selection techniques. This unpredictability results in the expenditure of large research monies to develop a superior new corn inbred line.
The development of commercial corn hybrids requires the development of homozygous inbred lines, the crossing of these lines, and the evaluation of the crosses. Pedigree breeding and recurrent selection breeding methods are used to develop inbred lines from breeding populations. Breeding programs combine desirable traits from two or more inbred lines or various broad-based sources into breeding pools from which inbred lines are developed by selfing and selection of desired phenotypes. The new inbreds are crossed with other inbred lines and the hybrids from these crosses are evaluated to determine which have commercial potential.
Pedigree breeding is used commonly for the improvement of self-pollinating crops or inbred lines of cross-pollinating crops. Two parents which possess favorable, complementary traits are crossed to produce an F 1 . An F 2 population is produced by selfing one or several F 1 's or by intercrossing two F 1 's (sib mating). Selection of the best individuals is usually begun in the F 2 population; then, beginning in the F 3 , the best individuals in the best families are selected. Replicated testing of families, or hybrid combinations involving individuals of these families, often follows in the F4 generation to improve the effectiveness of selection for traits with low heritability. At an advanced stage of inbreeding (i.e., F 6 and F 7 ), the best lines or mixtures of phenotypically similar lines are tested for potential release as new cultivars.
Mass and recurrent selections can be used to improve populations of either self- or cross-pollinating crops. A genetically variable population of heterozygous individuals is either identified or created by intercrossing several different parents. The best plants are selected based on individual superiority, outstanding progeny, or excellent combining ability. The selected plants are intercrossed to produce a new population in which further cycles of selection are continued.
Backcross breeding has been used to transfer genes for a simply inherited, highly heritable trait into a desirable homozygous cultivar or inbred line which is the recurrent parent. The source of the trait to be transferred is called the donor parent. The resulting plant is expected to have the attributes of the recurrent parent (e.g., cultivar) and the desirable trait transferred from the donor parent. After the initial cross, individuals possessing the phenotype of the donor parent are selected and repeatedly crossed (backcrossed) to the recurrent parent. The resulting plant is expected to have the attributes of the recurrent parent (e.g., cultivar) and the desirable trait transferred from the donor parent.
Descriptions of other breeding methods that are commonly used for different traits and crops can be found in one of several reference books (e.g., Allard, 1960; Simmonds, 1979; Sneep et al., 1979; Fehr, 1987).
Proper testing should detect any major faults and establish the level of superiority or improvement over current cultivars. In addition to showing superior performance, there must be a demand for a new cultivar that is compatible with industry standards or which creates a new market. The introduction of a new cultivar will incur additional costs to the seed producer, the grower, processor and consumer; for special advertising and marketing, altered seed and commercial production practices, and new product utilization. The testing preceding release of a new cultivar should take into consideration research and development costs as well as technical superiority of the final cultivar. For seed-propagated cultivars, it must be feasible to produce seed easily and economically.
Once the inbreds that give the best hybrid performance have been identified, the hybrid seed can be reproduced indefinitely as long as the homogeneity of the inbred parent is maintained. A single-cross hybrid is produced when two inbred lines are crossed to produce the F 1 progeny. A double-cross hybrid is produced from four inbred lines crossed in pairs (A×B and C×D) and then the two F 1 hybrids are crossed again (A×B)×(C×D). Much of the hybrid vigor exhibited by F 1 hybrids is lost in the next generation (F 2 ). Consequently, seed from hybrid varieties is not used for planting stock.
Corn is an important and valuable field crop. Thus, a continuing goal of plant breeders is to develop stable, high yielding corn hybrids that are agronomically sound. The reasons for this goal are obviously to maximize the amount of grain produced on the land used and to supply food for both animals and humans. To accomplish this goal, the corn breeder must select and develop corn plants that have the traits that result in superior parental lines for producing hybrids. This requires identification and selection of genetically unique individuals which in a segregating population occur as the result of a combination of crossover events plus the independent assortment of specific combinations of alleles at many gene loci which results in specific genotypes. Based on the number of segregating genes, the frequency of occurrence of any individual with a specific genotype is less than 1 in 10,000. Thus, even if the entire genotype of the parents has been characterized and the desired genotype is known, only a few, if any, individuals having the desired genotype may fe found in a large F 2 or S 0 population. Typically, however, the genotype of neither the parents nor the desired genotype is known in any detail.
SUMMARY OF THE INVENTION
According to the invention, there is provided a novel inbred corn line, designated LH169. This invention thus relates to the seeds of inbred corn line LH169, to the plants of inbred corn line LH169 and to methods for producing a corn plant produced by crossing the inbred line LH169 with itself or another corn line. This invention further relates to hybrid corn seeds and plants produced by crossing the inbred line LH169 with another corn line.
DEFINITIONS
In the description and tables which follow, a number of terms are used. In order to provide a clear and consistent understanding of the specification and claims, including the scope to be given such terms, the following definitions are provided:
Predicted RM. This trait for a hybrid, predicted relative maturity (RM), is based on the harvest moisture of the grain. The relative maturity rating is based on a known set of checks and utilizes conventional maturity systems such as the Minnesota Relative Maturity Rating System.
MN RM. This represents the Minnesota Relative Maturity Rating (MN RM) for the hybrid and is based on the harvest moisture of the grain relative to a standard set of checks of previously determined MN RM rating. Regression analysis is used to compute this rating.
Yield (Bushels/Acre). The yield in bushels/acre is the actual yield of the grain at harvest adjusted to 15.5% moisture.
Moisture. The moisture is the actual percentage moisture of the grain at harvest.
GDU Silk. The GDU silk (=heat unit silk) is the number of growing degree units (GDU) or heat units required for an inbred line or hybrid to reach silk emergence from the time of planting. Growing degree units are calculated by the Barger Method, where the heat units for a 24-hour period are: ##EQU1## The highest maximum used is 86° F. and the lowest minimum used is 50° F. For each hybrid, it takes a certain number of GDUs to reach various stages of plant development. GDUs are a way of measuring plant maturity.
Stalk Lodging. This is the percentage of plants that stalk lodge, i.e., stalk breakage, as measured by either natural lodging or pushing the stalks determining the percentage of plants that break off below the ear. This is a relative rating of a hybrid to other hybrids for standability.
Root Lodging. The root lodging is the percentage of plants that root lodge; i.e., those that lean from the vertical axis at an approximate 30° angle or greater would be counted as root lodged.
Plant Height. This is a measure of the height of the hybrid from the ground to the tip of the tassel, and is measured in centimeters.
Ear Height. The ear height is a measure from the ground to the ear node attachment, and is measured in centimeters.
Dropped Ears. This is a measure of the number of dropped ears per plot, and represents the percentage of plants that dropped an ear prior to harvest.
DETAILED DESCRIPTION OF THE INVENTION
Inbred corn line LH169 is a yellow dent corn with superior characteristics, and provides an excellent parental line in crosses for producing first generation (F 1 ) hybrid corn. This inbred is a medium season field corn inbred and is best adapted for the North Central region of the United States.
Inbred corn line LH169 was developed from the cross LH82×LH124 by selfing and using the ear-row pedigree method of breeding. Yield, stalk quality, root quality, ear retention, disease tolerance, late plant greenness, late plant intactness, pollen shedding ability, silking ability and corn borer tolerance were the criteria used to determine the rows from which ears were selected. Selfing and selection were practiced within the above F 1 cross for seven generations in the development of LH169. During the development of the line, crosses were made to inbred testers for the purpose of estimating the line's general and specific combining ability, and evaluations were run by the Williamsburg, Iowa and Stanton, Minn. Research Stations. The inbred was evaluated further as a line and in numerous crosses by the Williamsburg and Stanton Research Stations and other research stations across the Corn Belt. The inbred has proven to have a very good combining ability in hybrid combinations and to produce hybrids which are better adapted for several environments within the Corn Belt.
The inbred has shown uniformity and stability for all traits, as described in the following variety description information. It has been self-pollinated and ear-rowed a sufficient number of generations, with careful attention to uniformity of plant type to ensure homozygosity and phenotypic stability. The line has been increased both by hand and sibbed in isolated fields with continued observation for uniformity. No variant traits have been observed or are expected in LH169.
Inbred corn line LH169, being substantially homozygous, can be reproduced by planting seeds of the line, growing the resultant corn plants under self-pollinating or sib-pollinating conditions with adequate isolation and harvesting the resultant seed, using techniques familiar to the agricultural arts.
Inbred corn line LH169 has the following morphologic and other characteristics (based primarily on data collected at Williamsburg, Iowa):
VARIETY DESCRIPTION INFORMATION
A. Maturity
INBRED=LH169
Best Adapted For: North Central Region of Corn Belt
Heat Unit Silk: 1390 ##EQU2## B. Plant Characteristics Plant height (to tassel tip): 173 cm.
Length of top ear internode: 14 cm.
Number of ears per stalk: Slight two-ear tendency
Ear height (to base of top ear): 60 cm.
Number of tillers: None
Cytoplasm type: Normal
C. Leaf
Color: 5 GY 4/4 Munsell Color Charts for Plant Tissue
Angle from stalk: 30°-60°
Marginal waves: few
Number of leaves (mature plants): 12
Sheath pubescence: Light
Longitudinal creases: Few
Length (ear node leaf): 68 cm.
Width (widest point of ear node leaf): 9 cm.
D. Tassel
Number of lateral branches: 7
Branch angle from central spike: 30°-40°
Pollen shed: Heavy
Peduncle length (top leaf to basal branch): 5 cm.
Anther color: Yellow
Glume color: Green
E. Ear (Husked Ear Data Except When Stated Otherwise)
Length: 16 cm.
Weight: 82 gm.
Midpoint diameter: 39 mm.
Silk color: Green
Husk extension: Medium
Husk leaf: <8 cm.
Taper of Ear: Slight
Position of shank (dry husks): Upright
Kernel rows: 18
Husk color (fresh): Light green
Husk color (dry): Buff
Shank length: 9 cm.
Shank (no. of internodes): 9
F. Kernel (Dried)
Size (from ear midpoint)
Length: 11 mm.
Width: 8 mm.
Thickness: 4 mm.
Shape grade (% rounds): 60-80
Pericarp color: Colorless
Aleurone color: White
Endosperm color: Yellow
Endosperm type: Normal starch
Gm Weight/100 seeds (unsized): 21 gm.
G. Cob
Diameter at midpoint: 29 mm.
Strength: Strong
Color: White
H. Disease Resistance
Northern Leaf Blight (NLB): Tolerant
Northern Leaf Spot Race 3 (NLSR3): Tolerant
Eyespot: Susceptible
This invention is also directed to methods for producing a corn plant by crossing a first parent corn plant with a second parent corn plant, wherein the first or second corn plant is the inbred corn plant from the line LH169. Further, both first and second parent corn plants may be from the inbred line LH169. Therefore, any methods using the inbred corn line LH169 are part of this invention: selfing, backcrosses, hybrid breeding, and crosses to populations. Any plants produced using inbred corn line LH169 as a parent are within the scope of this invention. Advantageously, the inbred corn line is used in crosses with other corn varieties to produce first generation (F 1 ) corn hybrid seed and plants with superior characteristics.
As used herein, the term "plant" includes plant cells, plant protoplasts, plant cell of tissue culture from which corn plants can be regenerated, plant calli, plant clumps, and plant cells that are intact in plants or parts of plants, such as pollen, flowers, kernels, ears, cobs, leaves, husks, stalks, and the like.
Tissue culture of corn is described in U.S. Pat. Nos. 4,665,030, 4,806,483 and 4,843,005, incorporated herein by reference. Corn tissue culture procedures are also described in Green and Rhodes, "Plant Regeneration in Tissue Culture of Maize", Maize for Biological Research (Plant Molecular Biology Association, Charlottesville, Va. 1982), at 367-372. Thus, another aspect of this invention is to provide for cells which upon growth and differentiation produce the inbred line LH169.
LH169 closely resembles the LH82 parent, both in plant and ear type. LH82 is also the best comparison to LH169 because of LH82's long and substantial commercial success in hybrid combinations. LH169 as a line flowers earlier than either of its parents, and in specific hybrid combinations it flowers very early. LH169 in hybrid combinations is earlier flowering, has higher grain yield and lower grain moistures at harvest than LH82 in corresponding hybrid combinations, while standability appears similar. LH169 hybrids are 1-2% lower in harvest moisture. While the LH169 hybrids favor the LH82 hybrids in appearance, they have late season intactness and better tolerance to second brood corn borer damage. Observations suggest that LH169 will have better tolerance to some diseases than LH82, including Northern Leaf Blight and Northern Leaf Spot Race 3. LH169 is a good pollinator. The combination of traits--yield, dry down and disease tolerance--makes LH169 uniquely different from its parents and other corn lines.
TABLES
In the tables that follow, the traits and characteristics of inbred corn line LH169 are given in hybrid combination. The data collected on inbred corn line LH169 is presented for the key characteristics and traits. The tables present yield test information about LH169. LH169 was tested in several hybrid combinations at eight locations, with two or three replications per location. Information about these hybrids, as compared to several check hybrids, is presented.
The first pedigree listed in the comparison group is the hybrid containing LH169. Information for the pedigree includes:
1. Mean yield of the hybrid across all locations.
2. A mean for the percentage moisture (% M) for the hybrid across all locations.
3. A mean of the yield divided by the percentage moisture (Y/M) for the hybrid across all locations.
4. A mean of the percentage of plants with stalk lodging (% SL) across all locations.
5. A mean of the percentage of plants with root lodging (% RL) across all locations.
6. A mean of the percentage of plants with dropped ears (% DE).
7. The number of locations indicates the locations where these hybrids were tested together.
The series of hybrids listed under the hybrid containing LH169 are considered check hybrids. The check hybrids are compared to hybrids containing the inbred LH169.
The (+) or (-) sign in front of each number in each of the columns indicates how the mean values across plots of the hybrid containing inbred LH169 compare to the check crosses. A (+) or (-) sign in front of the number indicates that the mean of the hybrid containing inbred LH169 was greater or lesser, respectively, than the mean of the check hybrid. For example, a +4 in yield signifies that the hybrid containing inbred LH169 produced 4 bushels more corn than the check hybrid. If the value of the stalks has a (-) in front of the number 2, for example, then the hybrid containing the inbred LH169 had 2% less stalk lodging than the check hybrid.
TABLE 1______________________________________Overall Comparisons ofLH202 × LH169 Hybrids Vs. Check Hybrids Mean % %Hybrid Yield % M Y/M SL RL % DE______________________________________LH202 × LH169 184 19.12 9.62 4 2 0(at 15 Loc's)as compared to:LH206 × LH82 +22 -2.13 +2.02 0 +2 0LH202 × LH167 +10 -1.62 +1.20 -1 +2 0Pioneer 3751 +11 -.21 +.65 0 0 0LH74 × LH163 +22 +.13 +1.11 +1 0 0LH202 × LH163 +19 +.18 +.90 -1 +1 0A632 × LH163 +32 +1.40 +1.05 0 0 0______________________________________
TABLE 2______________________________________Overall Comparisons ofLH206 × LH169 Hybrids Vs. Check Hybrids Mean % %Hybrid Yield % M Y/M SL RL % DE______________________________________LH206 × LH169 169 19.67 8.59 4 1 0(at 12 Loc's)as compared to:LH206 × LH82 +7 -2.26 +1.19 -2 +1 0LH202 × LH167 -6 -1.53 +.34 -3 +2 0Pioneer 3751 -5 -.36 -.11 0 -1 0LH202 × LH163 +3 +.35 +.02 -2 0 0LH74 × LH163 +10 +.53 +.29 +1 -1 0A632 × LH163 +18 +1.71 +.16 -1 -1 0______________________________________
TABLE 3______________________________________Overall Comparisons ofLH74 × LH169 Hybrids Vs. Check Hybrids MeanHybrid Yield % M Y/M % SL % RL % DE______________________________________LH74 × LH169 171 21.14 8.07 2 4 0(at 14 Loc's)as compared to:LH74 × LH82 +4 -1.69 +.75 0 +3 0LH74 × LH61 +2 -.77 +.36 0 +3 0LH74 × LH167 -7 -.21 -.24 +1 +3 0LH211 × A641 -5 +.13 -.27 -1 -3 0LH222 × LH82 +2 +.49 -.10 -3 +3 0Pioneer 3751 -9 +.81 -.75 +1 +2 0LH74 × LH163 +8 +.92 +.01 +1 +4 0______________________________________
TABLE 4______________________________________Overall Comparisons ofLH163 × LH169 Hybrids Vs. Check Hybrids Mean %Hybrid Yield % M Y/M SL % RL % DE______________________________________LH163 × LH169 156 22.66 6.89 2 1 0(at 13 Loc's)as compared to:LH74 × LH167 -15 -3.36 +.32 -1 +1 0Pioneer 3751 -27 -2.05 -.52 -1 0 0LH146 × LH82 +6 -2.02 +.82 -4 -1 0LH222 × LH61 -5 -1.38 +.19 -2 +1 0LH74 × LH85 +5 -.45 +.34 -3 0 0______________________________________
TABLE 5______________________________________Overall Comparisons ofLH146 × LH169 Hybrids Vs. Check Hybrids Mean % %Hybrid Yield % M Y/M SL RL % DE______________________________________LH146 × LH169 169 21.27 7.92 2 5 0(at 9 Loc's)as compared to:LH146 × LH167 +6 -1.68 +.83 +1 +4 0Pioneer 3751 -18 -1.63 -.23 +1 +2 0LH146 × LH82 +19 -1.31 +1.28 +1 +3 0LH223 × LH82 0 -.03 +.03 0 +3 0LH74 × LH85 +7 +.31 +.23 -1 +3 0______________________________________
TABLE 6______________________________________Initial Disease Ratings* ofLH169, LH82 and LH163 InbredDisease LH169 LH82 LH163______________________________________NLSR3 1.0 4.0 4.0NLB 2.0 4.0 6.0Eyespot 4.0 5.0 7.0______________________________________ *1-9 scale with 1 being resistant and 9 being highly susceptible
DEPOSIT INFORMATION
Inbred seeds of LH169 have been placed on deposit with the American Type Culture Collection (ATCC), Rockville, Md. 20852, under Deposit Accession Number 75617 on 3 Dec. 1993. A Plant Variety Protection Certificate is being applied for with the United States Department of Agriculture.
Although the foregoing invention has been described in some detail by way of illustration and example for purposes of clarity and understanding, it will be obvious that certain changes and modifications may be practiced within the scope of the invention, as limited only by the scope of the appended claims. | A novel inbred corn line, designated LH169, is disclosed. The invention relates to the seeds of inbred corn line LH169, to the plants of inbred corn line LH169 and to methods for producing a corn plant produced by crossing the inbred line LH169 with itself or another corn line. The invention further relates to hybrid corn seeds and plants produced by crossing the inbred line LH169 with another corn line. | 8 |
This is a streamline continuation of application Ser. No. 572,939 filed Apr. 29, 1975, now abandoned.
BACKGROUND OF THE INVENTION
1. FIELD OF THE INVENTION
The object of the present invention is a process for fast firing of ceramic products and particularly of wall-tiles or floor-tiles or other uses.
2. DESCRIPTION OF THE PRIOR ART
The conventional process used for the production of tiles involves a double-firing process wherein the body of the tile, after having been formed by pressing the raw material, or in any other suitable way, is fired as it is and it is subsequently glazed on one of its faces and finally the glaze is fired.
The conventional process, which is used for a wide range of ceramic products, provides products of the desired quality, but it is obviously time consuming and expensive and attempts have been made to replace it with faster and cheaper processes, particularly by the so-called single firing processes in which the ceramic body is coated with the glaze after drying and subsequently the glazed body is fired in a single-phase.
The single-phase firing processes are more critical and difficult than the conventional one and have been carried out more or less successfully according to the raw materials used and the shape and nature of the required product. However, these do not always afford the desired savings, for instance in cases in which the single-firing requires a considerable length of time and produces a poor quality product or a high rate of rejects.
The relative fast single-firing is feasible, as well known in the art, by using certain raw materials, especially batches with a high content, for example 70%, of talcum and wollastonite.
However, such a method of operation is economically advantageous only in some specific areas, like the United States, but not in most areas like Europe, South America and Asia, where, for economic reasons and according to the availability of materials, there is required the use of natural clay bodies or--depending on the areas--of bodies firing with clay, kaolin, calcium or magnesium carbonates, silica and feldspathic materials and other natural components as well as pre-treated or synthetic materials.
SUMMARY OF THE INVENTION
The present invention refers to the production of tiles made from such materials or bodies which will be referred to in the following specification with the term "clay materials", it being understood that materials containing high percentages (50% or more) of talcum and wollastonite, as well as those with the addition of clay as binder, are excluded from the above term.
Such "clay materials" may contain raw clays and or pre-fired clays as a certain percentage, at least about 40% of raw clay, is necessary to confer to the material the desired mechanical properties, and they must not contain, as mentioned above, substantial amounts of talcum and wollastonite. As far as the rest is concerned, they may contain various materials, such as siliceous or feldspathic sand and alkaline-earth, iron compounds and others.
The composition should be preferably such that the sum of magnesium and calcium oxides does not exceed much more than 20% by weight (a percentage of 30%, no doubt, should be excessive) and even better it should not exceed 20%, and that the percentage of aluminum oxide be contained within the same percentages. Even more preferably the composition may contain an amount of iron oxide of a few units percent (less than 10% ) by weight.
The object of the present invention is a process for singlefiring of tiles, which enables the production of perfect products in an exceptionally short time, as has never been achieved heretofore, and consequently with substantial savings, made of "clay materials", as specified above, thus obtaining final products of the highest quality, of regular geometric shape and free of defects.
The process according to this invention comprises the steps of advancing a raw tile made of "clay materials"--the term having the meaning as mentioned above--dried and covered on one face with the glazing material, also dried, through a heat treatment chamber, with both front and back planar faces substantially exposed to the direct transmission of heat by convection, the tile passing in the heat treatment chamber through a first phase of fast heating until it reaches a temperature slightly below the maximum firing temperature and through a subsequent firing phase where it is kept at temperatures within the range of the final heating temperature and the maximum firing temperature, the tile being then cooled.
By the term "direct transmission of heat by convection" it is meant that the tile is heated by moving hot gases, with nearly total exclusion, or without determining presence, of other types of heat transmission (such as the conduction from the supporting means on which the tile rests and/or radiation from the walls of the treatment chamber. Obviously, this is accomplished when the hot gases provide the sole heat source within the chamber and therefore they heat the tile as well as the supporting means and the walls (other high temperature bodies being placed into such a position as not to be able to directly contribute to the heating of the tiles).
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a schematic illustration of a tunnel-type furnace running longitudinally on a single plane, for practicing the invention; and
FIG. 2 is a schematic view of a supporting and feeding means for the tiles, i.e. two rollers carried by shafts supporting a moving tile, the roller shafts being controlled by any suitable means outside the furnace.
DETAILED DESCRIPTION OF THE INVENTION
Usually, the advancing of the tiles with both faces (which means the glazed face and the rear face, without taking into account the edges which are of relatively negligible surface) substantially exposed to the direct transmission of heat by convection, is obtained by bringing the tiles in successive contact with underlying transporting supports, preferably having a rotating surface and fixed axis, with each of which they come into contact ideally along a generatrix.
The feeding takes place at high speed, considerably higher than the speeds adopted heretofore for materials of this type, at the rate of 1.5-2 meters/minute (these figures not being considered binding), such speeds being optimum for wall-tiles, and therefore 4-5 mm. thick, but may be slightly reduced for thicker tiles.
The heat treatment chamber is temperature-controlled and usually comprises a tunnel-kiln where, in successive areas, the tiles go through the successive steps of heating and being maintained at the firing temperature (or briefly, firing, although proper firing actually starts during the heating step) and are subsequently cooled outside or partially cooled in the treatment chamber.
The drying of the ceramic body is a common operation in the manufacturing of ceramic products and may be usually carried out at a speed differing from that of the above mentioned operation or at the same speed when the dryer is an integral part of the kiln. The same applies to drying of the glazing. In the following description reference is made to a process wherein drying of the tile body is performed previously and separately while drying of the glazing is carried out immediately prior to heating and at the same speed. In this case it lasts a few minutes, for example from 5 to 7 minutes, at suitable temperatures, for example up to 200° C., and under an adequate and intense gas circulation.
When drying of the glazing is completed and the actual heat treatment starts, the temperature of the tiles, according to the present invention, is quickly raised up to the firing temperature. The firing temperature, measured near the tiles--as are all the temperatures stated in this specification--may vary quite substantially according to the compositions, but it is generally around 1000° C., as for example between 800° C. and 1200° C., but, more commonly, between 1000° C. and 1100° C., for example around 1050° C. and 1060° C.
The heating of the tiles is carried out, as referred to above, in an environment where heat transmission takes place by convection with gas flowing counter-current to the direction of travel of the tiles, and besides heating the tiles, it heats also the walls of the heat treatment chamber which are normally made of refractory material and at times may become incandescent, turning into a light-red colour. In these conditions the temperature difference between walls and tiles is always kept at an amount that such heat exchanges by radiation do not have a determining effect.
It is important to dose heating in the heating zone, so as to produce a quick rising of the temperature of the tile, the only upper limit with respect to the rapidity of heating, since the material may be damaged by a too quick evolution of volatile products, by uncontrolled thermal contraction and expansion in the still raw tile and such a limit is set case by case. Generally, a heating time of 4-6 minutes is considered adequate and at this point it may be assumed that the tile has reached--at least on the surface--a temperature a few degrees lower than chamber temperature. This temperature will be referred to as the "firing temperature".
During the actual firing step, the tile remains at a practically constant surface temperature (even if not exactly constant due to the fact that heat-exchanges still continue and the temperature of the chamber is not exactly constant) and continues to advance in the firing zone which is at an almost even temperature tending to be lower at the start and at the end due to closeness to the heating and cooling zones respectively, and with gas flowing counter-current. This step lasts slightly over 10 minutes, for example between 11 and 15 minutes.
In the meantime the heat penetrates more deeply in the tile body, firing the inner layers of the tile. Finally, the cooling step takes place in a time slightly shorter than the firing time, for example slightly shorter than 12 minutes, say 8-10 minutes, and may be determined by a partly directed and partly indirect cooling and occurs partially inside and partially or entirely outside the chamber.
The times specified above by way of example are close to optimum for wall-tiles, 4-5 mm. thick, and may be increased, with a variation ratio generally not linear, for thicker tiles, such as those used for flooring, which may even be 10 mm thick and for which the length of time for heating may be for example up to 6-8 minutes and for firing 17-20 minutes.
It has been found, according to the present invention, that the best compromise between the necessity of suitably supporting the tile on the generatrices of the fixed-axis rotating supports for feeding, and the necessity of not introducing an excessive difference in the thermal conditions of the two faces of the tile, is obtained when the tile is kept in constant contact with two or three of these generatrices.
This is obtained in the more common case of the support by rotating rollers, when the distance between the centers of the rollers is equal to half the length of the tile itself. In such a case it is ensured that the product obtained is of regular geometric shape and free from defects. However, it is possible to modify to a reasonable extent this condition when in practice it is necessary to produce, with the same equipment, tiles of varying dimensions.
According to the present invention, the tile is formed of one of the bodies termed as "clay materials", as specified above. Typical materials forming the bodies are for example: plastic clays; no fat or semi-fat clays; kaolins; feldspars; dolomite and calcium carbonate; siliceous sand. The formulation of the glazing materials varies according to the required product and to the type of support used and may be raw, semi-raw, or fritted glazes.
In the carrying out the present invention there must be considered some physical properties of the material as specified in the following. A temperature/weight diagram of the material indicates a loss of weight with temperature increase according to the development of volatile substances.
With the increase in temperature and with the tile body kept at that temperature for some time, there appears first an increase and next, in the phase of specific interest, a loss of permeability of the tile body itself, which logically starts on the outer surfaces exposed to a quicker increase of temperature. The ceramic material used must have a total weight loss during the entire process, which although not very low when the above materials are dealt with, is however not excessive, for example, not more than 15%. In addition, it must be able to keep substantially its surface permeability at least up to a temperature of 700°-800° C. and until there is no substantial weight loss, as shown in the temperature/weight diagram, obviously under the conditions of the process according to this invention, particularly with the temperature-time gradients contemplated by the invention. Further, the thermo-dilatomeric behaviour of the material, i.e. variation of linear dimensions with increase in temperature, must be such as not to produce excessive difference in dimensions between the two faces of the tile, which due to the unavoidable unevenness in heating may not in fact be at the same temperature at least during some part of the process. Such behaviour of the material may be illustrated by plotting a thermo-dilatometric diagram.
By operating according to the invention, particularly under the preferred and optimum conditions, much better results are obtained, on an industrial scale, with respect to those obtained heretofore and actually beyond expectations. In the ceramic art the attempts made heretofore to introduce single-firing of tiles made of common materials which required a firing time of a few hours and resulted in the production of mostly defective tiles, led to the belief that such results were impossible. The speed increase, the lack of supports for the tile and the drastic reduction of operating times are all factors which, based on past technical experience, were supposed to be negative, so that it was assumed that manufacturing of excellent products from materials of the above mentioned type required operations under gentler, more gradual and mechanically easier condition than those previously adopted and not the contrary.
The fact that, by making all operating conditions simultaneously more severe, i.e. both speed and rapidity and mechanical feeding conditions of the tile, the result obtained was never achieved before even in conditions remotely approaching those of the invention, represents in fact a remarkable technical achievement.
For actuation practice of the invention a tunnel-type furnace running longitudinally on a single plane, as schematically illustrated in FIG. 1, is best suited.
The detailed structure is not shown, as it is not within the scope of the present invention, but generally comprises, assuming that drying of the tile body is carried out separately, a section 1 for drying of the glaze, a section 2 for the heating step, a section 3 for the firing step and a section 4 for the cooling step.
The furnace is conveniently heated by gas burners fitted in the walls so as not to radiate on the tiles, as schematically at 5, or by other suitable means, for example electric heating, the furnace walls being adequately insulated. In the case where gas burners are used, these will produce volumes of combustion by-products which will be conveniently moved counter-current with respect to the tile, travel by means of suitable suction devices (not shown) or other means so that gas masses increase from the outlet to the inlet of the treatment chamber and generally for the major portion of the chamber, usually in a linear manner. In the case of electric heating, air will have to be introduced to provide such volumes.
The elimination of moisture in area 1 may require a separate circulation of hot gas, as shown schematically at 6 (gas inlet) and 7 (outlet), the burners not being provided in this area. Suitable means will be provided to convey hot gases in counter-current flow with respect to the tiles and suitable means will thus be provided for loading and unloading of the tiles, as shown schematically at 8, driving the rollers at the required speeds and for speed control, and so on.
FIG. 2 shows an example of a supporting and feeding means for the tiles, two rollers 10 carried by shafts 11 supporting a moving tile 12; the roller shafts being controlled by any suitable means outside the furnace.
An example of carrying out the invention, illustrating the production of a particular tile, will now be given by way of example only, since the possibility of varying the compositions based on products available in nature for the industry is practically unlimited and skilled people in the art will be able to practice the invention based on what has hereinbefore been described in the specification without departing from the true scope of the invention even with compositions which are very different.
The initial material is a mixture of "red beds" clays having the following formulation: Ignit.loss 0-15%, SiO 2 55-70%, Al 2 O 3 15-20%, Fe 2 O 3 2-8%, CaO 1-10%, MgO 1-10%, K 2 O 1-6%, and Na 2 O 1-5%. The percentages are by weight.
The glaze used has the following composition: frits or glazes made of alkaline-boro-silicates containing Pb, Li, Ti, Ba, Ca, Mg, Sr, Sn, V, Zr: ceramic stains made of oxides or silicates or silico-aluminates of metals such as Fe, Co, Ni, Cr III, Ti, Mn, Cu, Zn, Ba, Zr, Sn, ecc.; various additives for grinding such as kaolins and clays, Zr silicates; sodium-silicate, -chloride and -carbonate.
The tiles are of two main types having dimensions of 150×150×4.5 and 200×200×9, respectively.
After pressing, drying and glazing the tiles are fed by means of rollers, as shown in FIG. 2, into an apparatus as illustrated in FIG. 1.
The feeding speed in the first case is 1.9 meters/minute and in the second case 1.4 meters/minute. Drying of the glaze lasts 5 and 6 minutes respectively, at a maximum temperature of 200° C. Heating lasts 5 and 6 minutes respectively. The time required for firing is 13 and 17 minutes respectively and the temperature measured in the chamber near the tiles is 1060° C. Cooling lasts 9 and 12 minutes respectively.
The tiles thus obtained are perfectly regular and meet the required technical specifications. | A process for the production of tiles made of ceramic material and having substantially planar front and back faces, comprising the steps of advancing a raw tile based on "clay material", with the term having the meaning as set forth in the description, dried and covered on one face with the glaze, which is also dried, in a heat treatment chamber with both faces at least substantially exposed to direct transmission of heat by convection, the tile in the heat treatment chamber going through a first fast heating phase until it reaches a temperature slightly lower than maximum firing temperature, and through a successive firing phase during which it is kept at a range of temperatures between the final heating temperature and the maximum firing temperature, the tile finally being cooled. | 2 |
GOVERNMENT INTEREST
The invention described herein may be manufactured, used, imported, sold, and licensed by or for the Government of the United States of America without the payment of any royalty thereon or therefor.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to permanent magnets and, more particularly, to high intensity permanent magnets having gradient fields and to methods of making such magnets.
2. Related Art
Permanent magnets that are capable of producing high intensity magnetic fields and that have a compact structure are known and are used, e.g., in miniaturized electrical components including disk drives for laptop and palmtop computers. In particular, permanent magnet materials that are highly remanent and coercive, such as those of the rare earth type, are produced to make compact flux sources of extraordinary strength. Examples of high-intensity, compact permanent magnets, which may employ these materials, may be found in the following patents. U.S. Pat. No. 4,837,542, to Leupold, entitled “Hollow Substantially Hemispherical Permanent Magnet High Field Flux Source for Producing a Uniform High Field”; U.S. Pat. No. 4,839,059 to Leupold, entitled “Clad Magic Ring Wigglers”; U.S. Pat. No. 5,103,200 to Leupold, entitled “High-Field Permanent Magnet Flux Source”; U.S. Pat. No. 5,216,401 to Leupold, entitled “Magnetic Field Sources Having Non-Distorting Access Ports”; U.S. Pat. No. 5,382,936 to Leupold et al., entitled “Field Augmented Permanent Magnet Structures”; U.S. Pat. No. 5,426,338 to Leupold, entitled “High-Power Electrical Machinery with Toroidal Permanent Magnets”; U.S. Pat. No. 5,434,462 to Leupold et al., entitled “High-Power Electrical Machinery”; and U.S. Pat. No. 5,523,731 to Leupold, entitled “Simplified Method of Making Light Weight Magnetic Field Sources Having Distortion-Free Access Ports. The entire contents of each of the foregoing patents is hereby incorporated herein by reference to the extent necessary to make and practice the present invention.
The basic configuration from which the magnetic arrangements described above are derived may be referred to as a Halboch Structure or a magic cylinder or ring. The magic ring is a permanent magnet which is magnetized in accordance with the configuration shown in FIG. 1 . The orientation of magnetization at any point (P) is at an angle (γ) from a vertical axis (z) and is equal to twice the polar coordinate of P,(θ) or according to equation (1) as follows:
γ=(2)(θ) (1)
where:
(θ) is a polar angle between the x and z axes that may vary from θ=0° to θ=±0° as shown.
Such a magnetization pattern produces in an internal cavity (c) a uniform magnetic field (represented by arrow h). Ideally the change in direction of magnetization should be continuous but this is not technically feasible. Instead an approximation to the ideal magic ring structure can be formed by a method as described in U.S. Pat. No. 5,523,731, previously incorporated herein by reference. The method may comprise uniformly magnetizing a cylindrical shell along a plane defined by radii of the shell and cutting the shell into thin washer shaped pieces. Each of the washer-shaped pieces may then be cut in a radial manner to form truncated pie shaped pieces that may be then reversed 180° (turned upside down) and transposed to proper locations along the circumference of the ring to form a thin magic ring slice having the magnetization approximately as shown in FIG. 1 . The formation of a magic cylinder may be accomplished by stacking the magic rings together in an elongated fashion. It will be recognized that the ideal structure can be approached as closely as desired by increasing the number of truncated pie shaped pieces per magic ring.
It may be desired in particular applications employing magic rings or cylinders that access ports of various sizes, shapes and locations extend through the shell and communicate with the internal cavity (c). However, removal of magnetic material to provide an access port to the interior through the magnetic shell will distort the interior field especially in the vicinity of the port. To overcome this drawback, a further method is proposed, as also described in U.S. Pat. No. 5,523,731, wherein some of the thin washer-shaped pieces that are sliced from the uniformly magnetized cylinder are interleaved with the magic ring slices to form a cylinder that allows for non-distorting access ports. In such a case, removal of magnetic material results in a non-distorting access port, since a uniformly magnetized ring produces no field in its interior cavity and superposition of such a magnetization pattern upon that of ae magic ring would result in no change in the field located in the cavity of the magic ring.
It is also sometimes desired to produce permanent magnets having a shell and a cavity wherethrough a high intensity magnetic field extends which is tapered, or has a gradient. For example, electron-beam tubes often require gradient fields, which typically vary along a beam axis, for use in focusing and guiding the beam. Microwave and millimeter wave sources require an axial field variation of a longitudinal magnetic field in order to produce a crisp waveform and storage rings and particle accelerators may require transverse magnetic fields including field tapering in the direction of a longitudinal axis of a beam in order to compensate for changes in a velocity of the beam. In spectroscopic analysis, magnetic fields with a linear taper in the direction of the field are often used to produce a spectral distribution of absorbed or emitted electromagnetic energy.
U.S. Pat. No. 5,216,400 to Leupold (below referred to as the “400 Patent”), the entire contents of which is hereby incorporated herein by reference to the extent necessary to make and practice the present invention, describes a permanent magnet having a cavity and producing a magnetic field that varies in intensity and in the direction of its orientation to produce a tapered or gradient magnetic field within a cavity thereof. As generally described therein, to provide a linear taper along the z axis of a magnetic ring or cylinder where the south pole is at z=0 at an inner edge of a cavity, the remanence is tapered along the polar angle θ according to equation (2) as follows:
B r (θ)=mθ+B r Min (0°) (2)
where:
B r (θ) is the desired magnet remanence at θ; B r Min is the minimum remanence appropriate to produce a field H(Min) at the low end of the taper located in the cavity of the magnetic ring or cylinder and H(Max) being the field at the high end of the taper; and where m is found according to equation (3) as follows:
m=[B r Max (90°)−B r Min (0°)]/π (3)
where:
B r Max is the maximum remanence at z=d l at the north pole of the cavity and d i is the diameter of the cavity.
The permanent magnets described in the above patents and documents have numerous applications and advantages, however, it is desired to provide a permanent magnet including a cavity having both a gradient magnetic field and a distortion free access port.
SUMMARY OF THE INVENTION
In accordance with an embodiment of the present invention, a permanent magnet comprises a shell surrounding a cavity. The shell comprises a magnetic remanence B r (θ) configured such that a magnetic field taper extends through the cavity and wherein the shell also comprises a non-distortive access region that is substantially absent any magnetic field.
Another aspect of the present invention concerns a permanent magnet that comprises a shell surrounding a cavity and wherein the shell comprises a magnetic remanence configured whereby a magnetic field taper extends through the cavity. The remanence B r (θ) of the shell varying according to the formula:
B r (θ)=[(B r X (θ)) 2 +(B r Z (θ)) 2 ] 1/2
where:
B r X (θ)={[(B r Max −B r Min )/90°](θ)−B r Min }cos(90°−2θ); B r Z (θ)={[(B r Max −B r Min )/90°](θ)−B r Min }sin(90°−2θ)+(B r Max +B r Min )/2; (θ) is a polar angle between θ=0° to θ=±180°; B r Max is a maximum remanence desired; and B r Min is equal to a minimum remanence appropriate to produce a minimum magnetic field H(Min) of the magnetic field taper. The shell also comprises a pair of opposing non-distortive access regions substantially absent any magnetic field.
A further aspect involves a method of making a permanent magnet having a cavity, comprising providing at least one first segment having a first magnetic field that has a single predetermined direction of magnetization and that has a uniform first remanence; providing at least one second segment having a second magnetic field that has a direction of magnetization (γ) that varies circumferentially along the segment according to the formula γ=(2)(θ) where θ is a polar angle from θ=0° to θ=360° and wherein the second magnetic field comprises a second remanence which increases in magnitude from θ=0° to θ=180° and decreases in magnitude from θ=180° to θ=360°; and combining the at least one first segment and the at least one second segment to form a permanent magnet.
BRIEF DESCRIPTION OF THE DRAWINGS
The following detailed description is made with reference to the accompanying drawings, in which:
FIG. 1 is diagram showing a magnetic ring in accordance with the prior art;
FIG. 2 is a series of diagrams showing how magnetic fields of magnetic rings may be combined in accordance with an embodiment of the present invention;
FIG. 3 is a top view of a cylindrical permanent magnet showing various directions of magnetization in accordance with an embodiment of the present invention;
FIG. 4 is a perspective view of a magnetic ring having a uniform magnetic field;
FIG. 5 is a perspective view of a magnetic ring having a magnitude and direction of magnetization that varies with a change in polar angle;
FIG. 6 is a perspective view of a cylindrical permanent magnet in accordance with an embodiment of the present invention;
FIG. 7 is a perspective view of a first cylindrical blank magnetized with a uniform magnetic field and comprising a plurality of washer-shaped pieces;
FIG. 8 is a perspective view of a second cylindrical blank having a magnitude and direction of magnetization that varies with a change in polar angle and that comprises a plurality of magnetic ring slices;
FIG. 9 is an exploded view showing assembly of the first segments of FIG. 7 and the second segments of FIG. 8 to form the cylindrical permanent magnet of FIG. 6 ;
FIG. 10 is an end view of the cylindrical permanent magnet of FIG. 6 showing the various magnitudes and directions of magnetization;
FIG. 11 is an end view of the cylindrical permanent magnet of FIG. 6 showing the lines of flux extending through a bore of the magnet; and
FIG. 12 is an exploded view showing assembly of a spherical permanent magnet in accordance with another embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
One embodiment of the present invention concerns a permanent magnet that has both a cavity comprising a gradient magnetic field and a distortion free access port. In another embodiment of the invention, a permanent magnet may comprise a plurality of first and second segments that may be easily assembled together to provide the desired magnetic field parameters.
Referring to FIG. 2 , and in accordance with an embodiment of the present invention, a combination of magnetic rings, each having a particular magnetization, may be combined to form a magnetic ring having a particular resultant magnetization, the particulars of which may be found by vector analysis. For example, a first magnetic ring A including a magnetization direction and magnitude represented by arrows a may be combined with a magnetic ring B including a magnetization represented by arrows b (of equal magnitude to those of arrows a and in tandem at poles p where θ=0° and θ=180°) to form a magnetic ring C that has a resulting field reflected in arrows c 1 and voids or nulls in points c 2 , located at θ=±90°. It will be understood that since a magnetization of zero is present at the nulls, represented at points c 2 , material may be removed from the magnetic ring C at points c 2 in order to provide non-distortive access ports as described in more detail below. Within the magnetic ring C the magnetization (M) components vary in the x and z directions according to the following equations (4) and (5):
M x =M 0 sin(2θ); (4)
M z =M 0 (cos2θ+1); (5)
where:
M 0 is the magnetization of the material used and is equal to the remanence (B r ) divided by 4π (M 0 =B r /4π). It will be recognized that where a desired B r exceeds that of the best available material, an increase in the radius of the ring may be used to compensate for this.
In another example, by combining magnetic ring D including magnetization represented by arrows d with magnetic ring E including a magnetization represented by arrows e (of equal magnitude to those of arrows e and in opposition at poles p), a magnetic ring F is formed with a resulting field reflected in arrows f 1 and voids in points f 2 , located at θ=0° and 180°. Accordingly, material may be removed from the magnetic ring F and non-distortive access ports may be provided at points f 2 . Within the magnetic ring C the magnetization (M) components vary in the x and z directions according to the following equations (6) and (7):
M x =M 0 cos(2θ); (6)
M z =M 0 (sin θ+1). (7)
Referring now to FIG. 3 , a cylindrical permanent magnet having both-a gradient magnetic field in a cavity thereof and a distortion free access port in accordance with an embodiment of the present invention is shown generally at 200 . The permanent magnet 200 may comprise a shell 202 and a plurality of sections 204 . Each section 204 may be magnetized, as described in more detail below, such that both a direction of magnetization and a magnitude of magnetization may vary section by section. This is represented by the direction and length of arrows 206 .
Further in accordance with this embodiment, a non-distortive access region or notch 208 is provided for access to a cavity 210 . Also, a gradient magnetic field, represented by arrow 211 , resides within the cavity 210 .
It has been found that when a magnetization of two separate magnetic rings or cylinders, such as those illustrated in FIGS. 4 and 5 , are combined, a magnetization that results is consistent with the magnetization represented by the arrows 206 of the permanent magnet 200 of FIG. 3 .
Referring now also to FIG. 4 , a magnetic ring 210 may be magnetized by a uniform magnetic field to form a uniform remanence (B r1 ) as represented by the direction and length of arrows 212 . As is evident to one of ordinary skill in the art, generally no magnetic field is present within a cavity 213 of the magnetic ring 210 .
Referring now further to FIG. 5 , a magnetic ring 214 , which may be similar to that described in U.S. Pat. No. 5,216,400, above incorporated herein by reference, is shown which may be magnetized such that the direction of magnetization (γ) varies circumferentially along the segment according to the equation (8) as follows:
γ=(2)(θ) (8)
where:
(θ) is a polar angle between the x and z axes that may vary from θ=0° to θ=±180° as shown.
Arrows 216 are oriented in a manner to illustrate the direction of magnetization (γ) which varies about the circumference of the magnetic ring 214 . Arrows 216 also illustrate the magnitude of a remanence (B r2 ) which also varies about the circumference of the magnetic ring 214 . In particular, the remanence (B r2 ) generally increases from θ=0° to θ=180° and decreases from θ=180° to θ=0°. More specifically, the remanence (B r2 ) varies according to equation (9) as follows:
B r2 (θ)=mθ+B r Min (9)
where:
θis a polar angle from θ=0° to θ=±180°; and m varies according to equation (10) as follows:
m=(B r Max −B r Min )/90° (10)
where:
B r Max is the maximum remanence required to generate a maximum H(Max) magnetic field strength at the high end of a resulting tapered or gradient field represented by arrow 218 which is located within a cavity 220 of the magnetic ring 214 ; and B r Min is equal to the minimum remanence appropriate to produce a magnetic field H(Min) at the low end of a resulting tapered or gradient field represented by arrow 218 . B r Min is also equal to B r1 of the magnetic ring 210 .
Combining the uniform magnetization of the magnetic ring 210 with the varying magnetization arrangement of the magnetic ring 214 results in a varying magnetization such as that of the permanent magnet 200 of FIG. 3 . Since generally no magnetic field is present in the cavity 213 of the magnetic ring 210 , combining magnetic rings 210 and 214 results in no change to the tapered or gradient magnetic field of the magnetic ring 214 and thus is represented in the magnetic ring 200 by arrow 211 . Also since the remanences (B r1 ) and (B r2 ) are equal but opposite in direction where θ=0°, a non-distortive access region exists at θ=0° and notch 208 may be provided. Further, the direction of magnetization (γ), illustrated by the direction of arrows 206 , may be found in accordance with vector analysis as exemplified above in connection with FIG. 2 .
In accordance with vector analysis, the resulting remanence in the permanent magnet 200 for θ=0° to θ=±180° for each vector component of the remanence along the x direction may be found from equation (6) as follows:
B r X (θ)={[(B r Max −B r Min )/90°](θ)−B r Min}cos( 90°−2θ) (11)
Each vector component of the resulting remanence along the z direction for θ=0° to θ=±180° may be found from equation (12) as follows:
B r Z (θ)={[(B r Max −B r Min )/90°](θ)−B r Min }sin(90°−2θ)−B r Min (12)
The vector components B r X (θ) and B r Z (θ) may be combined to form a resultant remanence via equation (13) as follows:
B r (θ)=[(B r X (θ)) 2 +(B r Z (θ)) 2 ] 1/2 (13)
The direction of magnetization (γ) for each of B r (θ) may be found in accordance with equation (14) as follows:
tan(γ)=B r Z /B r X (14)
It will also be appreciated that the particular location (θ) of the notch 208 (or slot in the case of a cylinder) may be varied depending upon a desired location for distortion free access. For example, distortion free access may be provided in the permanent magnet 200 at θ=90° and at θ=270° by modifying the uniform remanence (B r1 ) of the magnetic ring 210 to equal (B r Max +B r Min )/2 whereby the following equations (15) and (16) for vector components of the remanence are obtained.
B r X (θ)={[(B r Max −B r Min )/90°](θ)−B r Min }cos(90°−2θ) (15)
B r Z (θ)=[((B r Max −B r Min )/90°)(θ)−B r Min ]sin(90°−2θ)+(B r Max +B r Min )/2 (16)
The vector components B r X (θ) and B r Z (θ) may be combined to form a resultant remanence via equations (13) and (14) above.
It will be appreciated that the above-described equations may be used in connection with a sphere, although, the resulting distortion free access ports are cylindrical tunnels at the poles and an equatorial slot at the equator.
Optional Embodiment For Simple Assembly
Referring now to FIG. 6 , a permanent magnet, in accordance with another embodiment of the present invention, is illustrated generally at 10 . In this embodiment, the permanent magnet 10 comprises a plurality of segments 12 , 14 each having an aperture 16 . As illustrated, each of the segments 12 , 14 are magnetized, as described in more detail below, and may be concatenated together to create a magnetic field within the apertures 16 which is tapered or increases in strength in the direction of the arrow 18 and which comprises a non-distortive access region or notch 19 .
The segments 12 , or washer-shaped pieces and shown also in FIG. 7 , may be cut (illustrated by dashed lines 19 ) from a cylindrical blank 20 that may comprise any suitable material capable of high remanence and thereby producing a high strength magnetic field such as a composition that includes a rare earth element. The cylindrical blank 20 may be magnetized by a uniform magnetic field to form a uniform remanence (B r1 ) as represented by the direction and length of arrows 22 .
Referring to FIG. 8 , a cylindrical blank 24 is shown from which segments 14 , or magnetic ring slices, may be cut (as illustrated by dashed lines 26 ). The cylindrical blank 24 may comprise a similar material to that of the cylindrical blank 20 , although, it will be appreciated that other materials capable of high remanence may be employed. The cylindrical blank 24 may be magnetized such that the direction of magnetization (γ) varies circumferentially along the segment similar to that described above in connection with FIG. 5 and according to the equations (9) and (10) above. Accordingly, arrows 28 are oriented in a manner to illustrate the direction of magnetization that varies about the circumference of the cylindrical blank 24 . Arrows 28 also illustrate the magnitude of the remanence (B r2 ) which also generally increases from θ=0° to θ=180° and decreases from θ=180° to θ=360° as described above.
FIG. 9 illustrates assembly of the permanent magnet 10 , whereby segments 12 and 14 are interleaved together to form an elongated structure. It will be appreciated that the permanent magnet 10 may comprise a notch 30 ( FIG. 5 ) which may be formed prior to or after assembly of the segments 12 and 14 .
Referring now also to FIGS. 10 and 11 , after assembly of the permanent magnet 10 , the permanent magnet may have a resultant magnetic field remanence (represented by arrows 32 ) that includes a general null at the notch 30 and an increasing field strength (H) along a z axis through cavity 16 . As shown, H(min) represents a minimum field strength within the cavity 16 while H(max) represents a maximum field strength.
Another embodiment of a permanent magnet in accordance with the present invention is illustrated generally at 110 in FIG. 12 . The permanent magnet 110 may be similar to permanent magnet 10 in many aspects except that, instead of a generally cylindrical configuration, the permanent magnet 110 comprises a generally spherical configuration. Accordingly, similar components are labeled with similar reference numbers excepting that a one is included in the reference number for those referring to permanent magnet 110 .
The permanent magnet 110 comprises segments 112 and 114 each of which comprise a magnetic remanence B r1 and B r2 (represented by arrows 122 , 128 , respectively) which may be similar to that described above in connection with FIGS. 2 and 3 . Therefore, reference may be had above to segments 12 and 14 for further details concerning segments 112 and 114 .
Segments 112 and 114 may be cut from spherical blanks (not shown) which have been magnetized appropriately, as described above, and then assembled together by interleaving the segments 112 and 114 as shown. Also, the segments 112 and 114 may comprise a notch 130 that may be formed, e.g., prior to assembly thereof.
While the present invention has been described in connection with what are presently considered to be the most practical and preferred embodiments, it is to be understood that the present invention is not limited to these herein disclosed embodiments. Rather, the present invention is intended to cover all of the various modifications and equivalent arrangements included within the spirit and scope of the appended claims. | A permanent magnet comprises a shell surrounding a cavity. The shell has a magnetic remanence B r (θ) configured such that a magnetic field taper extends through the cavity and wherein the shell includes a non-distortive access region that is substantially magnetic field. | 7 |
BACKGROUND
[0001] The use of N 6 -(ferrocenmethyl)quinazoline-2,4,6-triamine as an antimicrobial, antibiotic, microbicide, bacteriological, bacteriostatic, antiparasitic, antiprotozoal, or antileishmanial agent has not been previously reported.
[0002] Since the emergence of leishmaniasis in 1885, few agents have been described and used in the treatment of this disease, and these agents have variable efficiency and effectiveness. Therapeutic options are rare and include expensive drugs that are difficult to obtain, lack a coordinated registry, and may be toxic or ineffective. Antimonials, for example (including the meglumine antimoniate), were introduced in 1940 and continue to be the treatment of choice for cutaneous leishmaniasis, although the treatment regimens are longer than 20 days and can induce pancreatitis (the most frequent reason that treatment is discontinued) as well as serious electrocardiographic changes. Amphotericin B, which is nephrotoxic and hypercalcemic, is also used (Alvar J, et al., 1997. Clin. Microbiol. Rev. 10: 298-319; Alvar J, et al., 2008. Clin. Microbiol. Rev. 21: 334-359).
[0003] Other compounds used as antiparasites, such as metronidazole, present variable results, which in general reflects a lack of evidence regarding these drugs. Recently, the in vitro leishmanicidal activity of hydroxyurea was described (Martinez-Rojano H, et al., 2008. Antimicrob. Agents Chemother. 52: 3642-3647), although in vivo evidence has not been reported.
THE SUBJECT MATTER OF THE INVENTION
[0004] The present invention refers to the human or veterinary use of a compound that contains N 6 -(ferrocenmethyl)quinazoline-2,4,6-triamine, as well as its derivatives and prodrugs, as an antimicrobial (antibiotic, microbicide), antiparasitic (parasiticide), antiprotozoal (protozoacide), or antileishmanial (leishmanicide) agent.
[0005] The N 6 -(ferrocenmethyl)quinazoline-2,4,6-triamine compound, which we refer to as H2, presents antimicrobial, antiparasitic, and leishmanicide activity from 0.1 μg/ml to greater than 100 μg/ml. H2 can be used in the treatment of infections caused by microorganisms, parasites, and protozoa, including members of the Leishmania genus in particular.
DESCRIPTION OF FIGURES
[0006] FIG. 1 : The biological activity of H2 toward the in vitro growth of Leishmania mexicana strain MHOM/MX/01/Tab3. A growth curve collected after 72 hours of parasite cultivation in a Neubauer chamber in the presence of the H2 is shown. The H2 concentration is shown on the horizontal axis, whereas the number of parasites/ml is shown on the vertical axis. The experiment was performed at room temperature using high-glucose Dulbecco's Modified Eagle's Medium with 10% fetal bovine serum.
[0007] FIG. 2 : Photograph obtained using an inverted microscope showing the inhibition of Leishmania growth by H2. The parasite culture shown in the left image was grown under the same conditions described in FIG. 1 but with the absence of H2. The right image shows a culture grown in the presence of 1 μg/ml of the H2 compound, indicating a clear lack of growth and destruction of the parasite in the presence of H2.
[0008] FIG. 3 : A plot showing the H2 prodrug activity toward the in vitro growth of Leishmania Mexicana . To obtain a higher sensitivity in this experiment, the MNYC/BZ/62/M379 reference strain, which has a higher sensitivity to H2 than does MHOM/MX/01/Tab3, was used. The number of parasites/ml was determined at 72 hours of incubation using 100 mM of each compound in four replicates. The culture conditions were the same as described in FIG. 1 .
[0009] FIG. 4 : An example of biological activity of H2 parenterally administered at a dose of 0.1 mg/mL in 100 μl of physiological saline solution; a) and c) correspond to the activity prior to treatment, b) is a control using only a saline solution, and d) is the condition with H2. Images b) and d) were collected at 14 days after treatment.
[0010] FIG. 5 : An example of the biological activity of the HA2 prodrug dissolved in drinking water and orally administrated at a dose of 1 mg/mL ad libitum for 3 days; a) before treatment, b) three months after treatment, c) six months after treatment, and d) seven months after treatment.
DESCRIPTION OF THE INVENTION
Description of the Compound
[0011] The compound N 6 -(ferrocenmethyl)quinazoline-2,4,6-triamine (H2) is a solid substance at room temperature and atmospheric pressure. Its contains carbon, hydrogen, nitrogen and iron (II) and has a molecular weight of 374 a.m.u., a condensed molecular formula C 19 H 19 N 5 Fe, and the following chemical structure:
[0000]
[0012] H2 presents the following physicochemical properties:
[0013] Melting point: 210.6-211° C.
[0014] R f : 0.53 (2-butanol/acetic acid/water 80:20:5)
[0015] Infrared spectrum (KBr): 3369 and 3244 (N—H), 1693 and 1668 (C═O), 823 (C—H ferrocene).
[0016] Proton nuclear magnetic resonance spectrum (DMSO-d 6 ): 3.98 ppm (t, J=6, 2H, CH 2 ), 4.10 ppm (t, J=3, 2H, ferrocene), 4.20 ppm (s, 5H, ferrocene), 4.32 ppm (t, J=3, 2H, ferrocene), 5.3 ppm (t, J=6, 2H, CH 2 ), 5.51 ppm (s, 2H, NH 2 ), 6.96 ppm (d, J=2.4, 1H, quinazoline), 7.02 ppm (s, 1H, NH 2 ), 7.04 ppm (br., s, 1H, quinazoline), 7.049 ppm (br, s, 1H, quinazoline).
[0017] Elemental analysis for C 19 H 20 FeN 5 : Calculated: C, 61.14; H, 5.13; N, 18.76. Measured: C, 61.14; H, 4.92; N, 18.03.
[0018] H2 synthesis is initiated by the condensation of N,N′-(6-aminoquinazoline-2,4-diyl)diacetamide with ferrocencarboxaldehyde in dimethylformamide (DMF). Subsequent reduction with sodium borohydride (NaBH 4 ) gives HA2, which produces H2 in a 62% yield when hydrolyzed in a methanolic sodium hydroxide solution.
[0000]
[0019] It is also possible to prepare H2 prodrugs, i.e., compounds with the same base structure that form H2 when metabolized in a living organism.
[0000]
TABLE
H2 Prodrugs
No.
R 1
R 2
R 3
HA2
NHC(O)CH 3
NHC(O)CH 3
H
2
NHCOCH 2 CH 2 COOH
NH 2
H
3
NH 2
NHCOCH 2 CH 2 COOH
H
4
NHCOCH 2 CH 2 COOH
NHCOCH 2 CH 2 COOH
H
5
NHCOCH 2 CH 2 COONHC(NH)NH 2
NH 2
H
6
NH 2
NHCOCH 2 CH 2 COONHC(NH)NH 2
H
7
NHCOCH 2 CH 2 COONHC(NH)NH 2
NHCOCH 2 CH 2 COONHC(NH)NH 2
H
[0020] These compounds can be obtained using the following process:
[0021] The synthesis of prodrugs 2 and 3 is initiated by reacting one equivalent of succinic anhydride with H2 in DMF. After stirring at room temperature until the reactants are consumed, the resulting suspension is separated by filtration. The mixture of the obtained compounds (2 and 3) is separated by open column chromatography using silica gel as the stationary phase and chloroform as the mobile phase. The synthesis of prodrugs 4 and 7 is initiated by reacting two equivalents of succinic anhydride with H2 in DMF. After stirring at room temperature until the reactants are consumed, the suspended solution is separated by filtration to obtain prodrug 4, which is reacted with dicyclohexylcarbodiimide and hydroxyurea in DMF at room temperature for 72 hours. The reaction mixture is separated by open column chromatography using silica gel as the stationary phase and a chloroform/methanol gradient as the mobile phase to obtain prodrug 7.
[0000]
Pharmaceutical Composition:
[0022] As part of the invention, the pharmaceutical compositions of H2, derivatives and prodrugs are also presented along with the pharmaceutically acceptable excipients. The following excipients can be employed for the compound synthesis: low-molecular-weight carboxymethylcellulose, high-molecular-weight carboxymethylcellulose, ethanol, Tween 20, Tween 80, Cremophor, polyethylene glycol, propylene glycol, glycerol, triethanolamine, lactose, alpha-cyclodextrin, beta-cyclodextrin, hydroxypropyl-beta-cyclodextrin, heptakis, methyl-beta-cyclodextrin, and gamma-cyclodextrin.
Administration Routes:
[0023] The administration of H2, derivatives or prodrugs to biological organisms is performed by any pharmaceutical route that is used and accepted for that purpose.
Biological Activity:
[0024] At greater than 5 μg/ml, H2 is lethal to Leishmania in less than 5 hours. The in vitro effect is apparent at 30 minutes after application. The parasite structure is modified such that it loses its characteristic form, loses refringence, becomes spherical, and is incapable of multiplying. H2 has a CL 50 of 2.6 μm/ml for the Leishmania mexicana MHOM/MX/01/Tab3 strain. The mechanism of cellular damage could not be identified by means of annexin for concentrations greater than 10 μg/ml; it is thought that a necrosis process rather than apoptosis is likely involved.
[0025] In comparison to other compounds with leishmanicidal activity, such as meglumine antimoniate, metronidazole, or hydroxyurea, H2 kills the total amount of parasites more quickly at up to 10-fold faster than any previously described compounds at doses that are ten-fold lower or less. H2 also presents activity against other protozoa, including Trypanosoma, Plasmodium, Entamoeba , and Giardia , as well as metazoan parasites and microorganisms in general.
[0026] Cytotoxicity against murine cells was not found in in vitro studies or in vivo studies using oral, parenteral, or dermal administration in mice. The compound was designed to specifically inhibit the activity of vital protozoan enzymes without activity in the human versions.
EXAMPLES
1) Synthesis
[0027] Using a 50 ml Florence flask equipped with magnetic stirring, a Vigreux column, and a nitrogen atmosphere, 0.31 g of ferrocencarboxaldehyde (0.00143), 0.3 g of N,N′-(6-aminoquinazoline-2,4-diyl)diacetamide (1 eq.), 1 ml of DMF, and a drop of acetic acid were combined. The mixture was stirred at 85° C. for 45 minutes. The mixture was cooled to 0° C. using an ice-water bath, and 0.0671 g (2 eq.) of NaBH 4 was slowly added. The ice bath was removed, and stirring was continued for 12 hours at room temperature. The DMF was evaporated in a rotatory evaporator, and a saturated solution of Na 2 CO 3 was added to the residue. The yellow precipitate that formed was separated by filtration and rinsed several times with water. After drying at room temperature, the solid was rinsed several times with diisopropyl ether to obtain 0.3239 g of HA2 with a 48% yield, R f =0.76 (CHCl 3 /MeOH 80:20) and p.f.=218-220° C. HA2 was hydrolyzed with one equivalent of a methanolic sodium hydroxide solution to obtain a precipitate that was separated by filtration. The solid was cleaned in methanol with activated carbon. From this procedure, 0.32 g of a yellow compound (H2) was obtained at a 62% yield, R f =0.53 (2-butanol/acetic acid/water 80:20:5) and p.f.=210.6-211° C.
2) Biological Activity
[0028] H2 (3 μg/ml) eliminates more than 90% of the parasites in Leishmania mexicana cultures (Tab3 or M379 strain) with 10 6 parasites/ml in Dulbecco's medium modified with 4.5 mg/mL glucose and 10% fetal bovine serum.
3) Pharmaceutical Preparation
[0029] To prepare a suspension of H2, 10 mg of the substance was dissolved in 1 ml of DMF. Subsequently, 100 μl of the solution was diluted with water (1:10) to obtain a suspension for oral administration to rodents.
4) H2 Derivatives
[0030]
[0000]
No.
R 1
R 2
R 3
8
NHC(O)CH 3
NHC(O)CH 3
CH 3
9
NHCOCH 2 CH 2 COOH
NH 2
CH 3
10
NH 2
NHCOCH 2 CH 2 COOH
CH 3
11
NHCOCH 2 CH 2 COOH
NHCOCH 2 CH 2 COOH
CH 3
12
NHCOCH 2 CH 2 COONHC(NH)NH 2
NH 2
CH 3
13
NH 2
NHCOCH 2 CH 2 COONHC(NH)NH 2
CH 3
14
NHCOCH 2 CH 2 COONHC(NH)NH 2
NHCOCH 2 CH 2 COONHC(NH)NH 2
CH 3
15
NHC(O)CH 3
NHC(O)CH 3
CH 3 CH 2
16
NHCOCH 2 CH 2 COOH
NH 2
CH 3 CH 2
17
NH 2
NHCOCH 2 CH 2 COOH
CH 3 CH 2
18
NHCOCH 2 CH 2 COOH
NHCOCH 2 CH 2 COOH
CH 3 CH 2
19
NHCOCH 2 CH 2 COONHC(NH)NH 2
NH 2
CH 3 CH 2
20
NH 2
NHCOCH 2 CH 2 COONHC(NH)NH 2
CH 3 CH 2
21
NHCOCH 2 CH 2 COONHC(NH)NH 2
NHCOCH 2 CH 2 COONHC(NH)NH 2
CH 3 CH 2
HO2
NH 2
OH
H
HO4
OH
NH 2
H
HO24
OH
OH
H
5) Prodrug Synthesis
[0031] In a 50 ml Florence flask equipped with magnetic stiffing, a Vigreux column, and a nitrogen atmosphere, 0.31 g of ferrocencarboxaldehyde (0.00143), 0.3 g of N,N′-(6-aminoquinazoline-2,4-diyl)diacetamide (1 eq.), 1 ml of DMF, and a drop of acetic acid were combined. The mixture was stirred at 85° C. for 45 minutes. The mixture was cooled to 0° C. in an ice-water bath, and 0.0671 g (2 eq.) of NaBH 4 was slowly added. The ice bath was removed, and stirring was continued for 12 hours at room temperature. Subsequently, the DMF was evaporated in a rotary evaporator. A saturated solution of Na 2 CO 3 was added to the residue. The yellow precipitate that formed was separated by filtration and rinsed several times with water. After drying at room temperature, the solid was rinsed several times with diisopropyl ether to obtain 0.3239 g of HA2 at 48% yield, R f =0.76 (CHCl 3 /MeOH 80:20) and p.f.=218-220° C.
6) Biological Activity of the HA2 Prodrug and the Derivatives HO2 and HO4
[0032] The following is a list of Leishmania mexicana growth inhibition activity by the prodrugs compared to H2 and a control.
[0000]
Compound
% of Leishmania Growth Inhibition
Control
0
HO2
20
HO4
25
FBC
32
HA2
24
H2
100
FBC: N-(ferrocenmethyl)aniline | The use of N 6 -(ferrocenmethyl)quinazoline-2,4,6-triamine (H2), its derivatives, and prodrugs that present antimicrobial (antibiotic, microbicide), antiparasitic (parasiticide), antiprotozoal (protozoacide), and antileishmanial (leishmanicide) activities, as well as its use as a drug in vertebrates (humans and animals). | 2 |
This application is a continuation of application Ser. No. 460,284, filed Jan. 24, 1983, now abandoned.
BACKGROUND OF THE INVENTION
This invention relates to a jewelry mounting construction especially adapted for incorporation with earring clamps and stickpins, and more specifically relates to a device for converting pierced-ear earrings into earrings capable of being clamped to unpierced ears, or into a stickpin.
Earrings have traditionally been available for use in pierced ears, or in unpierced ears. Pierced-ear earrings typically consist of a decorative object attached to a pin-like post; occasionally, pierced-ear earrings consist of a decorative object attached to a hooked pin or rod. When earrings are prepared with a post, they are conventionally secured to an earlobe by inserting the post through a hole pierced through an earlobe, and thereafter clamping an anchor attachment onto the post behind the earlobe so that the earring post cannot be removed from the ear without removing the anchor from the earring post. Earrings produced for use on earlobes that are not pierced must employ some form of clamping means attached to a decorative object, with the clamping means used to affix the decorative object to an earlobe. Normally, pierced ear earrings cannot be used on an ear that has not been pierced.
One aspect of the current jewelry industry is that the selection of pierced ear earrings far exceeds the selection of earrings adapted for use on unpierced ears. Moreover, the majority of higher quality decorative earrings are of the pierced ear type. Hence, persons desiring to wear earrings, but unable or unwilling to have their ears pierced, have a more limited selection of earrings to choose from.
Stickpins are forms of jewelry normally consisting of a decorative object attached to a long rod or pin with a pointed end. The rod or pin is inserted through clothing, and secured underneath the clothing, thereby allowing a person's decorative jewelry to be displayed wherever a person chooses. A limited selection of stickpins is, however, normally available. Moreover, stickpins are often sold as novelty items so that the quality of the decorative portion contained on a stickpin is often less than what an individual may desired.
Before this invention, persons without pierced ears who desired to use the decorative portion of a pierced-ear earring in nonpierced earrings, or as stickpins, were required to remove the decorative portion of the pierced-ear earring from the earring post or hook, and re-attach that decorative portion to a new clamp, such as the clamp disclosed in Saccoccio, U.S. Pat. No. 3,176,475 or to a stickpin. This is a delicate and somewhat tedious operation that usually can be accomplished only by a jeweler. Hence, persons desiring to use pierced-ear earring decorative portions have usually been required to take their chosen pierced-ear earrings to a jeweler for modification, with the delay and expense naturally attending to that action. Further, when decorative objects, such as diamonds, pearls, and delicately wrought precious metals, are removed from earrings, the operation, unless skillfully performed, may result in damage or disfiguration of the decorative portion of the earring.
An object of this invention is therefore to provide an improved jewelry mounting constuction for securing a decorative item onto the body or any apparel.
A further object of this invention is to provide an improved jewelry mounting construction capable of attaching pierced-ear earrings on nonpierced ears, and capable of supporting the decorative portion of a pierced-ear earring without removing that decorative portion from the earring post.
Another object of this invention is to provide an improved jewelry mounting construction for use as a stickpin.
Still another object of this invention is to provide an improved jewelry mounting construction for use as a stickpin receptacle capable of receiving the post or straightened hook attached to the decorative portion of a pierced ear earring.
SUMMARY OF THE INVENTION
These and other objects of the invention are accomplished by providing an improved jewelry mounting construction usable with an earring clamp or a stickpin. As an earring clamp, the mounting construction comprises a receptacle for receiving a pierced-ear earring post; in the preferred embodiment, the receptacle has a generally cylindrical bore in which the earring post may be inserted. The earring clamp also includes a means for securing the earring post in the receptacle bore, and a pincer jaw adapted to clasp an earlobe between the pincer jaw and the earring post receptacle. The clamping action of the improved earring clamp is provided by a leafspring affixed to the pincer jaw, and is elastically operated through motion of a leaver attached to spanning arm between the receptacle and the pincer jaw. In the preferred embodiment, the means for securing the earring post in the post receptacle is an elastic material affixed to the interior of the post receptacle bore, so that insertion of the earring post compresses the elastic material and produces frictional resistance to sliding movement of the post within the post receptacle bore. In an alternative embodiment, the post receptacle is filled with an elastic material that is puncturable and yieldable, such as an elastomeric adhesive.
The objects of this invention are also accomplished with a stickpin embodiment comprising a elongated pin or rod with a pointed end, and a second end affixed to a tubular earring post receptacle. The earring post receptacle has a means for securing the earring post in the receptacle, and the stickpin further comprises a pin retention attachment mountable on the pin at the stickpin's pointed end, to secure the stickpin in place when the stickpin has been attached to clothing or the like. In the preferred embodiment, the means for securing the earring post in the post receptacle comprises an elastic material affixed within the the center of the tubular post receptacle, so that insertion of the earring post into the post receptacle compresses the elastic material and produces frictional resistance to sliding movement of the earring post in the post receptacle.
BRIEF DESCRIPTION OF THE DRAWINGS
Two embodiments of the present invention are disclosed in the detailed description and drawings. The drawings include 6 figures to illustrate both embodiments, wherein like reference numerals in each drawing refer to like parts of the various embodiments. The drawings are briefly described as follows:
FIG. 1 is a side perspective view of the preferred embodiment of the invention depicting the improved earring clamp with a tubular earring post receptacle;
FIG. 2 is a side elevation of the earring clamp depicted in FIG. 1, showing operation of the leafspring mechanism;
FIG. 3 is a cutaway, side perspective view of the tubular post receptacle, depicting how a pierced-ear earring with an earring post may be inserted into the post receptacle to form a stickpin;
FIG. 4 is a side elevation of a second embodiment of the improved earring clamp;
FIG. 5 is a front plan view of the second embodiment depicted in FIG. 4;
FIG. 6 is a top plan view of the second embodiment depicted in FIGS. 4 and 5;
FIG. 7 is a side perspective view of a third embodiment of the improved earring clamp; and
FIG. 8 is a cutaway, side perspective view of a second embodiment of the tubular post receptacle and means for securing an earring post in the receptacle.
In the detailed description, directional terms such as "upper", and "lower" and the like, are used to relate the invention to the earlobe of a person oriented in the normally erect position. Terms of this type are used for the convenience of the person of ordinary skill in the art, and are not to limit the scope of any patent issuing on the present invention, unless expressly included in the claims.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention is a mounting construction for mounting jewelry on a persons body, or on an item of apparel. The jewelry is of the kind having a straight post for a support. Generally, the invention comprises a receptacle for receiving the support post of a piece of jewelry, and an attachment means for attaching the receptacle and jewelry to a part of the body, or to apparel. The receptacle is connected to the attachment means by being affixed to a support stud affixed to the attachment means.
Referring to FIGS. 1 and 2 of the accompanying drawings, a preferred embodiment of the present invention is incorporated in an earring clamp 10, so that the attachment means comprises a clamp for attaching jewelry to an earlobe. An alternative embodiment of the invention is shown in FIGS. 4, 5, and 6. The embodiment of FIG. 1 is regarded as the preferred mode of carrying out this invention. The earring clamp 10 is attached to a decorative jewelry piece 11, with a post 13.
The improved clamp can be set in two positions. The earring clamp 10 is shown in FIG. 1 in an open, or "cocked" position, and in FIG. 2 in a closed or "clamped" position. The earring clamp 10 includes a projecting stud 12, a post receptacle 14, and a pincer jaw 16. The pincer jaw 16 includes a contact surface 18 and a shank 20. The pincer jaw 16 is connected to the post receptacle 14 by a U-shaped spanning arm 22, the connecting portion of the spanning arm 22 being the projecting stud 12. The spanning arm 22 is inserted by the projecting stud 12 into the lower end of the post receptacle 14, and glued or soldered therein. The pincer jaw 16 with contact surface 18 and shank 20 comprises the attachment means for the mounting construction. The spanning arm 22 is the stud projecting from the attachment means and affixed to the receptacle, shown as post receptacle 14.
The earring clamp 10 is operated through use of a leafspring 24. The leafspring 24 is attached to the shank 20 at the shank's upper end by a clamp 26. The leafspring 24 interacts with the spanning arm 22, both to secure the pincer jaw 16 in an open or "cocked" position, and to exert pressure by the contact surface 18 against an earlobe when the pincer jaw 16 is in the closed position on an ear.
The leafspring 24 operates through pressure on a lever 28 extending from the spanning arm 22 as a continuation of spanning arm 22. The spanning arm 22 is pivotally connected to the pincer jaw 16 through axle arms 30 inserted through pivot holes 31. The leafspring 24 exerts pressure on the lever 28, thereby acting to restrain the lever 28 in a position roughly parallel to the shank 20. When the lever 28 is rotated in the pivot holes 31, the lever 28 is restrained in a position perpendicular to the shank 20, thereby lifting the leafspring 24 and "latching" the lever 28 against leafspring 24. Latching occurs when the lever 28 is perpendicular to the leafspring 24, so that the leafspring 24 cannot exert rotational force on the lever 28.
Referring to FIG. 3, the post receptacle 14 is shown in cutaway, and before attachment of the post receptacle to an earring post. FIG. 3 also illustrates an earring post 32 attached to the decorative portion 34 of an earring. FIG. 3 further illustrates a means for releasably securing an earring post 32 within the post receptacle 14. In the preferred embodiment, that means comprises a portion of an elastic, compressible material 36 affixed to the inner surface of the post receptacle 14. In the preferred embodiment, the compressible material is a strand of flexible, compressible fiber, such as polyurathane or plastic fiber. FIG. 3 therefore shows that the earring post 32 may be inserted into the post receptacle 14, causing a friction fit between the outer surface 38 of an earring post and the inner surface 40 of the earring post receptacle. The compression fit also operates through interaction between the outer surface 38 of the earring post and the compressible material 36.
FIG. 3 further illustrates use of the invention as a stickpin. The attachment means is a pin 42 sized to be slidably inserted into the lower end 42 of the post receptacle 14. The pin 42 has a tapered or pointed end 46 so that the pin 42 may be used as the portion of a stickpin that is inserted through clothing or other puncturable material. The upper end 48 of the pin 42 comprises the projecting stud of the attachment means and is therefore insertable in the lower end 44 of the post receptacle. In the preferred embodiment, the upper end 48 is secured within the post receptacle by means of an adhesive bonding agent such as glue. In alternative embodiments, the upper end 48 of the pin 42 can be secured to the lower end 44 of the post receptacle 14 by means of solder, or any other securing means.
Referring to FIGS. 4, 5, and 6, an alternative embodiment is displayed for the post receptacle 14, particularly for use with earrings. FIG. 4 illustrates a side view of an alternative embodiment 50 of the post receptacle. That alternative embodiment consists of a body 50 attached to the spanning arm 22. As shown in FIG. 5 and FIG. 6, the body 50 has an upper end portion which is U-shaped and the bight of the U-shape defines a earring post hole 52 in which an earring post may be inserted. The earring post hole 52 is oriented so that an earring post inserted through the hole 52 will be aligned parallel to the shank 20 of the pincer jaw 16 when the clamp is in the closed position. As shown in FIG. 5, the legs of the U-shape at the end of body 50 are formed by opposed gripper arms 56 and 54 depending from the portion of the body 50 defining the hole 52. The gripper arms 54 and 56 are positioned in opposed relationship, so that when an earring post, such as that illustrated as 32 in FIG. 3, is inserted through the hole 52, the earring post 32 is aligned approximately parallel to the gripper arms 54 and 56, and is thereby gripped by the lower portions of the gripping arms 54 and 56, to secure the post 32 within the gripper arms 54 and 56.
FIGS. 4, 5, and 6 further illustrate that the alternative embodiment 12 of the earring clamp operates through clamping action upon an ear or other material, with that clamping action applied by the body 50 and contact surface 18 of the pincer jaw 16. As in the preferred embodiment, the alternative embodiment receives its clamping action through operation of a leafspring (not shown) acting on the upper, pivot portion of the spanning arm 22. The pivot portion comprising a pivot hole 31 enclosing a axle arm 30. Again as in the preferred embodiment, the pincer jaw 16 may be latched in the open position, or the closed position as is shown in FIG. 4.
FIG. 3 further illustrates the method by which a pierced-ear earring may be converted to an earring suitable for use on unpierced ears, or to a stickpin. Considering FIG. 3 and FIG. 2, a method of converting pierced earrings begins by providing a clamp such as disclosed in FIG. 2; however, the clamp will not have the post receptacle 14, but would instead have an extended portion (not shown) of the spanning arm 22 constituting a clamping surface opposed to the contact surface 18. The extended portion of the spanning arm 22 is thereafter removed, leaving a clamp, such as is shown in FIG. 2, without the post receptacle 14. An earring post receptacle such as is shown in FIGS. 2 and 3 as 14 is then connected to the severed end 58 of the spanning arm 22. The earring post receptacle 14 is then securely affixed to the severed end 58 of the spanning 22, preferably by use of an adhesive bonding agent. Next, a means is provided for securing an earring post in the earring post receptacle 14. In the preferred embodiment, the means comprises a compressible material 36, such as a strand of polyurathane or plastic fiber, glued to the inner surface 40 of the post receptacle 14. The post receptacle 14 may also be sized for a simple friction fit between the outer surface 38 of the earring post and the inner surface 40 of the earring post receptacle. Thereafter, an earring must be prepared for insertion within the post receptacle 14, so that the decorative portion 34 of that earring may be properly displayed. In the preferred embodiment, this preparation comprises bending the earring post so that the decorative portion of the earring 34 is disposed away from the earring post 32. The preparation may also include tapering the lower end 60 of the earring post 32, to ease insertion of the earring post 32 into the post receptacle 14. If the pierced-ear earring has a hook, rather than a post, the hook must be mechanically straightened to form a post.
Referring to FIG. 7, a further alternative embodiment of the earring clamp is illustrated. Like the preferred embodiment, the embodiment illustrated in FIG. 7 contains a post receptacle 14 fixed to the severed end 58 of the spanning arm 22. Also as in the preferred embodiment, the alternative embodiment shown in FIG. 7 uses a lever 28 on the end of the spanning arm 22 interacting with the leaf spring to urge a shank 20 against the post receptacle 14; the leaf spring 24 is also attached to the shank 20 by a clamp 26, and the shank 20 rotates about axle arms 30 on the end of spanning arm 22, with the axle arms 30 extending through pivot holes 31 in the shank 20.
The alternative embodiment displayed in FIG. 7 differs from the preferred embodiment in that the upper end of the spanning arm 20 comprises a loop 62 pierced by a threaded bore 64 in the opposed sides of the loop. A tightening bolt 66 is threaded through the threaded bore 64 so that rotation of the tightening bolt urges the bolt towards or away from the post receptacle 14 when the shank 20 is in the closed position. A contact surface 68 is affixed to the tightening bolt 66 at its end nearest the post receptacle 14. A tightening handle 70 is affixed to the tightening bolt 66 at the tightening bolt's opposite end. In operation, manual rotation of the tightening handle 70 urges the tightening bolt 66 and contact surface 68 towards or away from the post receptacle 14, thereby increasing or decreasing the clamping pressure between the post receptacle 14 and the contact surface 68 when the shank 20 is in the closed position and the clamping mechanism is clamped on a body portion such as an ear lobe.
Referring to FIG. 8, an alternative embodiment of the means for securing the earring post to the post receptacle is illustrated. As in the preferred embodiment, the alternative embodiment shown in FIG. 8 includes a spanning arm 22 affixed within the post receptacle 14. Unlike the preferred embodiment, the friction means for securing the earring post 60 in the post receptacle 14 is a yieldable and puncturable elastic material such as an adhesive 72 inserted within the post receptacle 14. The adhesive 72 is preferably a silicone glue, such as is commonly used in many household adhesive compounds. Insertion of an earring post 60 in the post receptacle 14 then displaces portions of the adhesive 72, creating a friction fit between the outer surface of the earring post 60 and the inner surface of the post receptacle 14, thereby securing the earring post 60 against longitudinal movement within the post receptacle 14.
While preferred embodiments of the present invention have been set forth in the above detailed description, it is to be understood that the invention is limited only by the following claims and their equivalents. | An improved jewelry mounting construction for use in adapting pierced-ear earrings into earrings capable of being clamped on unpierced ears. Also disclosed is a construction for adapting pierced-ear earrings into stickpins. The improved construction comprises a clamping mechanism for securing a medium between opposed surfaces, one of those opposed surfaces being a receptacle for an earring post, with the receptacle having a means for securing the earring post of a pierced-ear earring therein. The mechanism for adapting pierced-ear earrings into stickpins comprises a post receptacle affixed to an elongated pin, with a means for securing an earring post therein. | 8 |
FIELD OF THE INVENTION
The present invention relates generally to the field of implantable stimulators and more particularly to cardiac pacemakers and implantable antiarrhythmia devices.
BACKGROUND OF THE INVENTION
Multi-site atrial pacing, for example bi-atrial pacing, is a known method of reducing the incidence of atrial tachyarrhythmias. In this pacing mode, atrial pacing electrodes are located at two sites within the atria. In response to sensing an atrial depolarization at one site, pacing pulses are delivered either to both sites or to the site at which the depolarization was not sensed. In the context of this pacing mode, the issue of whether to provide a pacing pulse or pulses in response to a sensed atrial premature depolarization, also referred to as a premature atrial contraction (PAC) has arisen, as in some cases pacing pulses synchronized to PACs can be pro-arrhythmic.
The issue of the possible pro-arrhythmic effect of PAC synchronized atrial pacing pulses is dealt with in the article “Multisite Pacing for AF management—Technical and Clinical Challenges”; Mehra, et al., Journal of Interventional Cardiac Electrophysiology, 2000; 4:69-79, incorporated in its entirety by reference herein. In this article, it is proposed that pacing pulses should not be delivered synchronized to PACs occurring at short coupling intervals from previous atrial depolarizations, but should be delivered synchronized to PACs having longer coupling intervals. An exemplary pacemaker for accomplishing this result is disclosed in U.S. Pat. No. 5,403,356, issued to Hill, et al., also incorporated herein by reference in its entirety. In this patent, a defined “APB interval” following an atrial depolarization is defined by the pacemaker. Non-refractory sensed PACs within this interval do not trigger synchronized pacing pulses. PACs sensed outside this interval do. In the particular embodiment disclosed in this patent, the duration of the APB interval varies as a result of sensed atrial rate. Automatic adjustment of anti-arrhythmia pacing modes and parameters generally is disclosed in U.S. Pat. No. 6,185,459, issued to Mehra, et al., also incorporated herein by reference in its entirety.
SUMMARY OF THE INVENTION
The present invention is directed to a method and apparatus for automatically adjusting the duration of an APB interval as in the Hill, et al. patent, to produce a minimum level of induced tachyarrhythmias. Generally, this desired result is accomplished by monitoring occurrences of atrial tachyarrhythmias following PACs and adjusting the APB interval accordingly. PACs are identified as being within a defined interval following a preceding sensed atrial depolarization or delivered atrial pacing pulse. Atrial tachyarrhythmia detection may be accomplished using any of the various known mechanisms.
In some embodiments, if an atrial tachyarrhythmia occurs following a PAC having an associated synchronized pacing pulse, the duration of the APB interval may be increased to extend past the coupling interval of the sensed PAC. Conversely, if an atrial tachyarrhythmia occurs following a sensed PAC without synchronized pacing, the APB interval may be reduced so that the coupling Interval of the sensed PAC is outside the APB interval. In some embodiments, adjustment of the APB interval may occur following a single occurrence of an atrial tachyarrhythmia following a PAC. In other embodiments, adjustment of the APB interval may require multiple occurrences of atrial tachyarrhythmia's occurring in the presence of PACs at or about a specific coupling interval. In some embodiments, the numbers of sensed tachyarrhythmias at different PAC coupling intervals may be stored in the form of a histogram to facilitate this analysis.
The invention may be practiced in a pacemaker as in the Hill, et al. patent, in which the APB interval is varied as a function of atrial rate or in pacemakers in which the APB interval is not rate-variable. Further, while the invention is disclosed herein in its simplest form, i.e. a bi-atrial pacer, the invention may also be incorporated into multi-site atrial pacemakers with ventricular sensing and pacing functions similar to those disclosed in the cited Mehra, et al. patent. The invention of course may also be incorporated into devices such as anti-arrhythmia pacemakers and implantable cardioverter-defibrillators, which have the capability of treating detected tachyarrhythmias.
Finally, while the invention is disclosed in the context of a bi-atrial pacemaker, it is also believed useful in the context of other multi-site atrial pacemakers. For example, the invention may be practiced in pacemakers in which electrodes are located in the right atrial appendage and Triangle of Koch, as disclosed in the cited Hill, et al. patent or in which synchronized atrial pacing occurs at more than two sites.
BRIEF DESCRIPTION OF THE DRAWINGS
These and other advantages and features of the present invention will be appreciated as the same becomes better understood by reference to the following detailed description of the preferred embodiment of the invention when considered in connection with the accompanying drawings, in which like numbered reference numbers designate like parts throughout the figures thereof, and wherein:
FIG. 1 is a drawing illustrating the interconnection of a cardiac pacemaker according to the present invention with the right and left atria of a human heart.
FIG. 2 is a block functional diagram of a cardiac pacemaker appropriate for use in practicing the present invention.
FIG. 3 is a simulated electrogram tracing in conjunction with a timing chart, indicating the operation of the various time intervals defined by a pacemaker according to a preferred embodiment of the invention.
FIG. 4 is an exemplary histogram illustrating one method of storing and organizing information related to occurrences of tachyarrhythmias occurring at different PAC coupling intervals
FIG. 5 is a functional flowchart, illustrating the basic operation of a pacemaker according to a preferred embodiment of the invention.
FIG. 6 is a functional flow chart generally illustrating adjustment of the APB interval according to a preferred embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the drawings described below, identically numbered components in the various drawings should be understood to be identical structures or steps.
FIG. 1 shows an implantable pacemaker 10 , according to the present invention, and its interconnection to a human heart 30 . The pacemaker is provided with two leads 14 and 16 , coupled to the pacemaker by means of a connector block 12 .
Leads 14 and 16 take the form of bipolar endocardial leads, of the type presently available and widely marketed for use in conjunction with cardiac pacemakers. These leads are provided with proximal electrodes ( 18 , 22 ) and distal electrodes ( 20 , 24 ). The electrode 24 adjacent the distal end of lead 14 is a helical electrode screwed into the tissue of the right atrium. Pacing and sensing using this lead is accomplished using ring electrode 22 and electrode 24 . Lead 16 is located in the coronary sinus and is similarly employed to sense and pace the left atrium using electrodes 18 and 20 . Other electrode locations within or adjacent to the atria may also be employed in conjunction with the present invention. For example, electrodes located in the triangle of Koch may be employed in conjunction with electrodes located in an area displaying prolonged refractory periods. Alternatively, electrodes located in an area displaying prolonged refractory periods may be employed in conjunction with electrodes located elsewhere in the right atrium. Alternatively, three or more electrode locations in or adjacent the right and/or left atria may be employed.
FIG. 2 is a block, functional diagram of a pacemaker appropriate for use in conjunction with the present invention. Because the diagram as illustrated makes use of presently available components and circuitry, only the basic functional operation as it relates to the present invention is described in detail. As a practical matter, it is believed that any of the available microprocessor controlled dual chamber (DDD, VDD) pacemakers presently on the market can readily be modified to practice the present invention, as they typically include all of the basic functional components illustrated.
In the embodiment illustrated, operation of the pacemaker is controlled by the microprocessor 100 , under control of programming stored in read only memory (ROM) 102 . Random access memory (RAM) 104 serves to store those parameters which are programmable by the physician, to store measurements made by the pacemaker and values calculated by the microprocessor. The RAM 104 may also be employed to store electrograms sensed by the pacemaker.
Microprocessor 100 is coupled to timing and control circuitry 106 by means of a data/address bus 108 . Timing and control circuitry 106 takes the form of a number of counters or timers for defining the time intervals discussed below in conjunction with FIG. 3 . The time intervals provided are intended to be programmable and to be varied under control of microprocessor 100 .
Pulse generator 110 is coupled to electrodes 114 and 116 , which may correspond to the electrodes located on lead 14 , in FIG. 1 . In particular, electrode 114 may correspond to ring electrode 22 , and electrode 116 may correspond to the helical electrode 24 . Pulse generator circuitry 112 is coupled to electrodes 118 and 120 , which may correspond to the electrodes on lead 16 ( FIG. 1 ). In particular, electrode 118 may correspond to ring electrode 18 , and electrode 120 may correspond to electrode 20 in FIG. 1 . Sense amp 122 is coupled to electrodes 114 and 116 . Sense amp 124 is coupled to electrodes 118 and 120 .
Timing/control circuitry 106 , in the context of the present invention, defines a number of basic timing intervals. The first timing interval is the escape interval, corresponding to basic pacing rate of the device, as is conventional in cardiac pacemakers. In response to time-out of the escape interval, timing/control circuitry 106 triggers pulse generators 110 and 112 to deliver cardiac pacing pulses. Time out of the escape interval also serves as an interrupt, triggering microprocessor 100 to perform any necessary calculations or updating and to reset the timers within timing/control circuitry 106 .
Also defined by timing/control circuit 106 are blanking and refractory periods, corresponding functionally to blanking and refractory periods in traditional cardiac pacemakers and applicable to both sense amps 122 and 124 . During the blanking period, sense amps 122 and 124 are disabled. During the portion of the refractory period extending beyond the blanking period, sense amps 122 and 124 are enabled. However, atrial depolarizations sensed by either sense amp during this period will not function to reset the basic rate interval. During the refractory period, sensing for noise or other interference may also be conducted, as currently done in conjunction with presently available cardiac pacemakers. In the event that a delay is provided between the sensing of depolarizations and delivery of pacing pulses, the control/timing circuitry would function to time this delay as well.
Timing/control circuitry 106 also defines the APB interval discussed above. In some embodiments, the APB interval may vary as a function of the measured atrial rate, over a preceding series of beats. For example, APB may be a defined percentage (e.g. one-half) of the average interval separating atrial depolarizations, over a preceding series of 8 beats. In such embodiments, this percentage may be adjusted as a function of the occurrences of tachyarrhythmias following PACs, as discussed in more detail below.
In response to an atrial depolarization sensed by amplifier 122 , following the APB interval, timing/control circuitry 106 may trigger only pulse generator 112 to deliver a pacing pulse or may trigger both pulse generators 110 and 112 to deliver pacing pulses. Similarly, in response to an atrial depolarization sensed by amplifier 124 , outside the APB interval, timing/control circuitry 106 may trigger only pulse generator 110 to deliver a pacing pulse or may trigger both pulse generators 110 and 112 to deliver pacing pulses. Microprocessor 100 is interrupted, and the escape interval, blanking interval, refractory interval and APB intervals timed by control/timing circuitry 106 are reset. The A-A interval is stored for later reference. A-A intervals which are less than a defined duration are flagged by the microprocessor as PAC coupling intervals and are employed to update the APB interval responsive to occurrences of atrial tachyarrhythmias as discussed below.
In embodiments employing a rate variable APB interval, microprocessor 100 may also update a running average of the preceding series of A-A intervals between sensed and paced atrial depolarizations, based on the time of occurrence of the most recent depolarization. Microprocessor 100 may then recalculate a new APB interval, based on the updated average. In response to a depolarization sensed by amplifier 122 , within the APB period, microprocessor 100 is interrupted, and the escape interval, blanking interval, refractory interval and APB intervals timed by control/timing circuitry 106 are reset. The A-A interval (PAC coupling interval) is stored for later reference. Timing/control circuitry 106 does not trigger pulse generator 112 to deliver a pacing pulse or pulses. In those embodiments employing rate-variable APB intervals the A-A interval ending in the premature atrial beat is not employed to update the running average of the A-A intervals.
In the event that the escape interval times out, pacing pulses are delivered by output circuits 110 and 112 , microprocessor 100 is interrupted and the escape interval, blanking interval, refractory interval and APB intervals timed by control/timing circuitry 106 are reset. In those embodiments employing rate-variable APB intervals the escape interval is used to update the average A-A interval, purposes of calculating a new value of the APB interval.
In the context of the present invention, the microprocessor 100 is also employed to analyze the occurrences and timing of atrial depolarizations to detect occurrences of tachyarrhythmias, especially atrial tachyarrhythmias. This analysis may be as simple as detection of an excessively high rate, or may employ measurements of other factors such a rate stability, suddenness of rapid rate onset depolarization waveform morphology or the like. Any known method of tachyarrhythmia detection may be employed, as the invention does not depend on any particular mechanism for tachyarrhythmia detection. Exemplary mechanisms for tachyarrhythmia detection may be found in U.S. Pat. No. 5,658,320 issued to Betzold et al., U.S. Pat. No. 5,968,079 issued to Warman, et al., U.S. Pat. No. 5,991,657 issued to Kim, U.S. Pat. No. 6,895,272 issued to Siem et al. and U.S. Pat. No. 6,052,620 issued to Gillberg et al, all incorporated herein by reference in their entireties. The particular detection methodology chosen will of course depend on the configuration of the pacemaker, e.g. whether it includes ventricular sensing capabilities.
In response to detection of an atrial tachyarrhythmia, the microprocessor 100 preferably determines whether the tachyarrhythmia is associated with a preceding PAC. This may be accomplished by determining whether a PAC occurred within a defined number of beats or a defined time interval prior to onset of the detected tachyarrhythmia. If so, the PAC's coupling interval is stored as part of a histogram. The histogram includes a number of defined bins, each of which extends over a range of PAC coupling intervals and stores a number indicating the number of occurrences of measured PAC coupling intervals occurring within the range defined by the bin. The histogram may extend over a defined number of preceding stored PACs, over a defined duration, or may simply continue to be updated until reset. The microprocessor 100 examines the histogram to determine whether any of the bins holds a value which meets a threshold number, indicating that PAC coupling intervals in this range are associated with occurrences of tachyarrhythmias. If the threshold is reached, the microprocessor adjusts the APB interval accordingly. This procedure is discussed in more detail in conjunction with FIGS. 4-6 .
FIG. 3 illustrates a simulated electrocardiogram (ECG) and associated timing charts, showing the interrelation of the various time intervals defined by the apparatus of FIG. 2 . The simulated ECG begins with a paced atrial depolarization at 200 . This event occurs as the result of a time out of the base pacing rate interval at 202 , triggering pacing pulses delivered by both pulse generators (PACE 110 and PACE 112 ) at 204 and 206 , respectively. Also illustrated are the refractory interval 208 , initiated in responses to delivery of pacing pulses at 204 and 206 and the APB interval 210 , similarly initiated following delivery of pacing pulses. APB interval 210 is updated by the microprocessor, following delivery of the pacing pulses, and extends for a predetermined period corresponding to a proportion or fraction of the current average atrial rate.
At 212 , a spontaneous atrial depolarization is sensed by sense amp 122 . Because depolarization 212 follows the expiration of APB interval 210 , a pacing pulse 214 is delivered by pulse generator 112 . Alternatively, pacing pulses may be delivered by both pulse generators, as discussed above. The refractory interval 216 and escape interval 218 are restarted. In embodiments employing rate variable APB intervals, the APB interval 220 is updated by the microprocessor and correspondingly restarted. At 222 , a premature atrial beat occurs, coming before time-out of APB interval 220 . In response to the atrial premature beat 222 , the refractory period 224 , APB period 226 and escape interval 228 are all restarted. However, in embodiments employing rate variable APB intervals, APB interval 226 is not updated to take into account the interval between depolarizations 212 and 222 .
At 230 , the basic rate interval times out, triggering delivery of pacing pulses 232 and 234 , by both pulse generators. The refractory interval 236 and the escape interval 238 are both restarted. In embodiments employing rate variable APB intervals, APB interval 240 is updated to reflect the A-A interval (the escape interval) between spontaneous depolarization 222 and delivery of the cardiac pacing pulses at 232 , 234 .
FIG. 4 is an exemplary histogram of a type that may be employed in conjunction with the present invention. The histogram defines a number of bins A-G, extending along a time axis 252 . Preferably the bins define time interval ranges extending between a minimum available APB interval duration (MINAPB) and a maximum available APB interval duration (MAXAPB). Depending on the specific implementation of the device, the bins may either be of defined duration range or a defined percentage of the range between APBMIN and APBMAX. A defined numerical threshold T is indicated along a vertical numeric axis 250 . In the simplest embodiment, the value of T could be set equal to one, resulting in adjustment of the APB interval following a single detected tachyarrhythmia. Alternatively, the value of T is set by the physician as indicative of an undesirable number of occurrences of tachyarrhythmias over the time duration or number of intervals reflected in the histogram, with the hope that frequency of tachyarrhythmias can ultimately be reduced below this level by appropriate adjustment of the APB. The counts of PAC coupling intervals in each bin are illustrated by means of the associated vertically extending bar.
As illustrated, the duration of the APB interval is preferably located at the lower or upper interval duration for one of the bins. In embodiments employing rate variable APB intervals, the bins may need to be adjusted following rate-based adjustment of the APB as discussed hereinbelow (e.g. bin ranges adjusted upward or downward) in order to maintain this relationship. In response to detection of an atrial tachyarrhythmia, the microprocessor 100 checks to determine whether any bin has a count that meets the threshold. If so, the duration of the APB interval is adjusted. If the bin meeting the threshold extends over intervals less than the duration of the APB interval, this indicates that PACs occurring in that interval range were not accompanied by synchronized pacing. The duration of the APB interval may then be set equal to the lower duration of the bin meeting the threshold to assure that subsequent PACs in this interval range are accompanied by synchronized pacing. If the bin meeting the threshold contains intervals greater than the APB interval, this indicates that the PACs in that interval range were accompanied by synchronized pacing. The duration of the APB interval may then be set equal to the lower duration of the bin meeting the threshold to assure that subsequent PACs in this interval range are not accompanied by synchronized pacing. Following adjustment of the APB interval based on occurrences of atrial tachyarrhythmias, the histogram is preferably cleared or reset.
In an even simpler embodiment, the histogram could be dispensed with entirely. The APB interval could be reset following an atrial tachyarrhythmia associated with a PAC by simply adjusting the APB interval to be greater than the coupling interval of the PAC if synchronized pacing was delivered and adjusting the APB interval to be less than the coupling interval of the PAC if synchronized pacing was not delivered.
FIG. 5 is a functional flow chart illustrating the operation of the device of FIG. 2 , as it practices the present invention. At 300 , the device is initialized. This may correspond to initial hook-up of the device to the battery, or to reprogramming of the device by physician. At 302 the microprocessor is awakened, resetting the time intervals in the control/timing circuitry, including the blanking interval, refractory interval, APB interval and escape interval. At 304 the device waits until the refractory interval has timed out.
When the refractory interval has timed out, the device awaits the occurrence of an atrial sense event at 306 or time out of the escape interval at 308 . If an atrial depolarization is sensed by either sense amp, the A-A interval is measured and stored. If its duration is short enough to qualify as a PAC, for example if it falls within the interval ranges defined in the stored histogram ( FIG. 4 ), the A-A interval (PAC coupling interval) is binned in the histogram at 314 . The microprocessor within the device checks at 320 to determine whether a tachyarrhythmia is present. If not, the device checks at 310 to determine whether the APB interval has timed out. This may be accomplished by the microprocessor, or by fixed logic within the timing/control circuitry.
If the APB interval has not timed out at the time the atrial depolarization is sensed, the device is simply reset at 302 , and the average A-A interval and APB intervals remain unchanged. If the APB interval has timed out when the atrial depolarization is sensed, at 112 the device delivers synchronized pacing pulses at one or both pairs of atrial electrodes as discussed above. The synchronized pacing pulse or pulses may be delivered essentially simultaneously with the detection of the atrial depolarization, or may be delivered following a short delay period, e.g. less than 50 ms.
If the device employs a rate variable APB, the A-A average is updated at 316 and a new APB value is calculated at 318 , as described in the cited Mehra et al. patent. The bin ranges of the histogram are also preferably adjusted upward or downward to retain the alignment of the APB interval with the end value of its associated bin value. If a rate variable APB interval is not employed, following delivery of synchronized pacing at 312 , the device simply returns to reset the timers at 302 .
In the event that no atrial depolarizations are sensed prior to timeout of the basic rate interval, as indicated at 308 , both pulse generators are activated at 324 . If the device employs a rate variable APB, The microprocessor updates the A-A average using the escape intervals the measured A-A interval, calculates a new APB interval at 318 , and the device is reset at 302 . Otherwise the device simply resets the timers at 302 .
In the event that an atrial tachyarrhythmia is detected at 320 , in embodiments in which antitachycardia therapies are available, they are delivered at 322 . While delivery of such therapies is not necessary for the present invention, it is anticipated that the invention may be practiced in devices capable of such therapy delivery. For example, devices as described in the above-cite Gillberg et al. patent. After detection at 320 or therapy delivery at 322 , the device determines whether the APB interval needs to be adjusted, as illustrated in FIG. 6 .
FIG. 6 is a functional flow chart illustrating the operation of the device to adjust the APB interval responsive to occurrence of atrial tacharrhythmias. Following detection of a tachyarrhythmia at 320 ( FIG. 5 ), the microprocessor within the device checks at 400 to determine whether the detected tachyarrhythmia was associated with a preceding PAC. For example, this may be accomplished by determining whether a preceding PAC occurred within a defined time period or number of beats preceding onset of the tachyarrhythmia. If not, the device may simply return to reset the timers at 302 ( FIG. 5 .) If a PAC is associated with the detected tachyarrhythmia, the device checks at 402 to determine whether the count in any of the histogram bins meets the defined threshold value. If not, the device may simply return to reset the timers at 302 ( FIG. 5 .)
If the count in a particular bin “BIN(T)” meets the threshold the device checks at 404 to determine whether the bin includes interval durations greater than the duration of the APB. If so, as discussed above in conjunction with FIG. 4 , the duration of APB is set equal to the maximum duration of BIN(T) at 408 . Otherwise, the duration of APB is set equal to the minimum duration of BIN(T) at 406 .
The basic operation of pacemakers according to the present invention can readily be extended to apply to systems employing three or more electrode locations. In response to a sensed depolarization at any of the electrodes, pacing pulses may be applied to all electrodes or only to the electrodes other than those through which the depolarization was sensed.
While the embodiment disclosed above employs separate sense amps and pulse generators for each electrode pair, It is believed within the scope of the present invention to employ fewer sense amps and pulse generators, so long as the required functions are present. For example, a single pulse generator could supply all electrodes with pacing pulse, with switching circuits to direct pulses to the desired electrodes or electrode pairs. Similarly, by switching, time multiplexing or other means, one sense amp could be shared by two or more electrodes or electrode pairs.
Further, while it is believed that for practical purposes, commercial implementations of devices employing the present invention will generally take the form of microprocessor controlled pacemakers, the invention and its associated functions may also readily be practiced by means of a pacemaker based on full custom digital integrated circuitry as widely practiced in the pacing industry, or may even be practiced in the form of a device fabricated of commercially available discrete components and circuits, so long as basic functions set forth above are preserved. Therefore, the disclosed embodiments should be considered exemplary, rather than limiting with regard to the claims that follow. | A multi-site atrial pacemaker capable of delivering pacing pulses to one location synchronized to sensed or paced atrial depolarizations on another location and a method of its use. A defined interval is defined following atrial depolarizations during which such synchronized atrial pacing pulses may not be delivered. The pacemaker automatically adjusts the duration of the defined interval to produce a minimum level of induced tachyarrhythmias. Generally, this desired result is accomplished by measuring coupling intervals of PACs, monitoring occurrences of atrial tachyarrhythmias associated with PACs and adjusting the defined interval accordingly. | 0 |
BACKGROUND OF THE INVENTION
[0001] Hemochromatosis is the most common progressive (and sometimes fatal) genetic disease in people of European descent. Hemochromatosis is a disease state characterized by an inappropriate increase in intestinal iron absorption. The increase can result in deposition of iron in organs such as the liver, pancreas, heart, and pituitary. Such iron deposition can lead to tissue damage and functional impairment of the organs.
[0002] In some populations, 60-100% of cases are attributable to homozygosity for a missense mutation at C282Y in the Histocompatibility iron (Fe) loading (HFE) gene, a major histocompatibility (MHC) non-classical class I gene located on chromosome 6p. Some patients are compound heterozygotes for C282Y and another mutation at H63D.
SUMMARY OF THE INVENTION
[0003] The invention is based on the discovery of novel mutations which are associated with aberrant iron metabolims, absorption, or storage, or in advanced cases, clinical hemochromatosis. Accordingly, the invention features a method of diagnosing an iron disorder, e.g., hemochromatosis or a genetic susceptibility to developing such a disorder, in a mammal by determining the presence of a mutation in exon 2 of an HFE nucleic acid. The mutation is not a C→G missense mutation at position 187 of SEQ ID NO:1 which leads to a H63D substitution. The nucleic acid is an RNA or DNA molecule in a biological sample taken from the mammal, e.g. a human patient, to be tested. The presence of the mutation is indicative of the disorder or a genetic susceptibility to developing it. An iron disorder is characterized by an aberrant serum iron level, ferritin level, or percent saturation of transferrin compared to the level associated with a normal control individual. An iron overload disorder is characterized by abnormally high iron absorption compared to a normal control individual. Clinical hemochromatosis is defined by an elevated fasting transferrin saturation level of greater than 45% saturation.
[0004] For example, the mutation is a missense mutation at nucleotide 314 of SEQ ID NO:1 such as 314C which leads to the expression of mutant HFE gene product with amino acid substitution I105T. The I105T mutation is located in the α1 helix of the HFE protein and participates in a hydrophobic pocket (the “F” pocket). The alpha helix structure of the α1 domain spans residues S80 to N 108 , inclusive. The I105T mutation is associated with an iron overload disorder.
TABLE 1 Human HFE cDNA sequence atgggcccg cgagccaggc cggcgcttct cctcctgatg cttttgcaga ccgcggtcct gcaggggcgc ttgctgcgtt cacactctct gcaccacctc ttcatgggtg cctcagagca ggaccttggt ctttccttgt ttgaagcttt gggctacgtg gatgaccagc tgttcgtgtt ctatgat cat gag agt cgcc H63D S65C gtgtggagcc ccgaactcca tgggtttcca gtagaatttc aagccagatg tggctgcagc tgagtcagag tctgaaa ggg tgggatcaca tgttcactgt tgacttctgg act att atgg G93R I105T aaaatcacaa ccacagcaag gagtcccaca ccctgcaggt catcctgggc tgtgaaatgc aagaagacaa cagtaccgag ggctactgga agtacgggta tgatgggcag gaccaccttg aattctgccc tgacacactg gattggagag cagcagaacc cagggcctgg cccaccaagc tggagtggga aaggcacaag attcgggcca ggcagaacag ggcctacctg gagagggact gccctgcaca gctgcagcag ttgctggagc tggggagagg tgttttggac caacaagtgc ctcctttggt gaaggtgaca catcatgtga cctcttcagt gaccactcta cggtgtcggg ccttgaacta ctacccccag aacatcacca tgaagtggct gaaggataag cagccaatgg atgccaagga gttcgaacct aaagacgtat tgcccaatgg ggatgggacc taccagggct ggataacctt ggctgtaccc cctggggaag agcagagata tacgtgccag gtggagcacc caggcctgga tcagcccctc attgtgatct gggagccctc accgtctggc accctagtca ttggagtcat cagtggaatt gctgtttttg tcgtcatctt gttcattgga attttgttca taatattaag gaagaggcag ggttcaagag gagccatggg gcactacgtc ttagctgaac gtgagtgaca cgcagcctgc agactcactg tgggaaggag acaaaactag agactcaaag agggagtgca tttatgagct cttcatgttt caggagagag ttgaacctaa acatagaaat tgcctgacga actccttgat tttagccttc tctgttcatt tcctcaaaaa gatttcccca tttaggtttc tgagttcctg catgccggtg atccctagct gtgacctctc ccctggaact gtctctcatg aacctcaagc tgcatctaga ggcttccttc atttcctccg tcacctcaga gacatacacc tatgtcattt catttcctat ttttggaaga ggactcctta aatttggggg acttacatga ttcattttaa catctgagaa aagctttgaa ccctgggacg tggctagtca taaccttacc agattcttac acatgtatct atgcattttc tggacccgtt caacttttcc tttgaatcct ctctctgtgt tacccagtaa ctcatctgtc accaagcctt ggggattctt ccatctgatt gtgatgtgag ttgcacagct atgaaggctg tgcactgcac gaatggaaga ggcacctgtc ccagaaaaag catcatggct atctgtgggt agtatgatgg gtgtttttag caggtaggag gcaaatatct tgaaaggggt tgtgaagagg tgttttttct aattggcatg aaggtgtcat acagatttgc aaagtttaat ggtgccttca tttgggatgc tactctagta ttccagacct gaagaatcac aataattttc tacctggtct ctccttgttc tgataatgaa aattatgata aggatgataa aagcacttac ttcgtgtccg actcttctga gcacctactt acatgcatta ctgcatgcac ttcttacaat aattctatga gataggtact attatcccca tttctttttt aaatgaagaa agtgaagtag gccgggcacg gtggctcgcg cctgtggtcc cagggtgctg agattgcagg tgtgagccac cctgcccagc cgtcaaaaga gtcttaatat atatatccag atggcatgtg tttactttat gttactacat gcacttggct gcataaatgt ggtacaacca ttctgtcttg aagggcaggt gcttcaggat accatataca gctcagaagt ttcttcttta ggcattaaat tttagcaaag atatctcatc tcttctttta aaccattttc tttttttgtg gttagaaaag ttatgtagaa aaaagtaaat gtgatttacg ctcattgtag aaaagctata aaatgaatac aattaaagct gttatttaat tagccagtga aaaactatta acaacttgtc tattacctgt tagtattatt gttgcattaa aaatgcatat actttaacaa atgtacactg tattgtaaaa aaaaaaa (SEQ ID NO:1; GENBANK ® Accession No. U60319)
[0005] TABLE 2 Human HFE gene product MGPRARPALLLLMLLQTAVLQG RLLRSHSLHYLFMGASEQDLGLSLFEALGYVDDQLFVFYD H E S RRVEPRTPWVSSRISSQ MWLQLSQSLK G WDHMFTVDFWTIMENHNHSK ESHTLQVILGCEMQEDNSTEGYWKYGYDG QDHLEFCPDTLDWRAAEPRAWPTKLEWERHKIRARQNRAYLERDCPAQLQQLLELGRGVL DQQVPPLVKVTHHVTSSVTTLRCRALNYYPQNITMKWLKDKQPMDAKEFEPKDVLPNGDG TYQGWITLAVPPGEEQRYTCQVEHPGLDQPLIVIWEPSPSGTLVIGVISGIAVFVVILFI GILFIILRKRQGSRGAMGHYVLAERE (SEQ ID NO: 2; GENBANK ® Accession No. U60319)
Residues 1-22=leader sequence; α1 domain underlined; residues 63, 65, 93, and 105 indicated in bold type)
Other mutations include nucleotide 277 of SEQ ID NO: 1, e.g., 277C which leads to expression of mutant HFE gene product G93R and one at nucleotide 193 of SEQ ID NO: 1, e.g., 193T, which leads to expression of mutant HFE gene product S65C.
[0006] Any biological sample containing an HFE nucleic acid or gene product is suitable for the diagnostic methods described herein. For example, the biological sample to be analyzed is whole blood, cord blood, serum, saliva, buccal tissue, plasma, effusions, ascites, urine, stool, semen, liver tissue, kidney tissue, cervical tissue, cells in amniotic fluid, cerebrospinal fluid, hair or tears. Prenatal testing can be done using methods used in the art, e.g., amniocentesis or chorionic villa sampling. Preferably, the biological sample is one that can be non-invasively obtained, e.g., cells in saliva or from hair follicles.
[0007] The assay is also used to screen individuals prior to donating blood to blood banks and to test organ tissue, e.g., a donor liver, prior to transplantation into a recipient patient. Both donors and recipients are screened.
[0008] In some cases, a nucleic acid is amplified prior to detecting a mutation. The nucleic acid is amplified using a first oligonucleotide primer which is 5′ to exon 2 and a second oligonucleotide primer is 3′ to exon 2. To detect mutation at nucleotide 314 of SEQ ID NO: 1, a first oligonucleotide primer which is 5′ to nucleotide 314 and a second oligonucleotide primer which is 3′ to nucleotide 314 is used in a standard amplification procedure such as polymerase chain reaction (PCR). To amplify a nucleic acid containing nucleotide 277 of SEQ ID NO: 1, a first oligonucleotide primer which is 5′ to nucleotide 277 and a second oligonucleotide primer which is 3′ to nucleotide 277 is used. Similarly, a nucleic acid containing nucleotide 193 of SEQ ID NO:1 is amplified using primers which flank that nucleotide. For example, for nucleotide 277, the first primer has a nucleotide sequence of SEQ ID NO: 3 and said second oligonucleotide primer has a nucleotide sequence of SEQ ID NO: 4, or the first primer has a nucleotide sequence of SEQ ID NO: 15 and said second oligonucleotide primer has a nucleotide sequence of SEQ ID NO: 16. Table 3, below, shows examples of primer pairs for amplification of nucleic acids in exons and introns of the HFE gene.
TABLE 3 I. PRIMERS USED FOR AMPLIFICATION Target DNA Forward Primer Reverse Primer Exon 2 CCTCCTACTACACATGGTTAAGG GCTCTGACAACCTCAGGAAGG (SEQ ID NO: 3) (SEQ ID NO: 4) Exon 3 GGTGGAAATAGGGACCTATTCC CACTCTGCCACTAGACTATAGG (SEQ ID NO: 5) (SEQ ID NO: 6) Exon 4 GTTCCAGTCTTCCTGGCAAGG AAATGCTTCCCATGGATGCCAG (SEQ ID NO: 7) (SEQ ID NO: 8) RT-PCR AAAGGATCCACCATGGGCCCGCGAGCCAGG GTGAGTCTGCAGGCTGCGTG (SEQ ID NO: 9) (SEQ ID NO: 10) Intron 4 GTTCCAGTCTTCCTGGCAAGG AAATGCTTCCCATGGATGCCAG (SEQ ID NO: 11) (SEQ ID NO: 12) Intron 5 GTTCCAGTCTTCCTGGCAAGG AAATGCTTCCCATGGATGCCAG (SEQ ID NO: 13) (SEQ ID NO: 14) II. PRIMERS USED FOR AMPLIFICATION Exon 2 GTGTGGAGCCTCAACATCCTG ACAAGACCTCAGACTTCCAGC (SEQ ID NO: 15) (SEQ ID NO: 16) Exon 3 GGTGGAAATAGGGACCTATTCC CACTCTGCCACTAGAGTATAGG (SEQ ID NO: 17) (SEQ ID NO: 18) Exon 4 GTTCCAGTCTTCCTGGCAAGG TTACCTCCTCAGGCACTCCTC (SEQ ID NO: 19) (SEQ ID NO: 20) RT-PCR AAAGGATCCACCATGGGCCCGCGAGCCAGG GTGAGTCTGCAGGCTGCGTG (SEQ ID NO: 21) (SEQ ID NO: 22) Intron 4 TGCCTGAGGAGGTAATTATGG AAATGCTTCCCATGGATGCCAG (SEQ ID NO: 23) (SEQ ID NO: 24) Intron 5 TGCCTGAGGAGGTAATTATGG AAATGCTTCCCATGGATGCCAG (SEQ ID NO: 25) (SEQ ID NO: 26)
[0009] Mutations in introns of the HFE gene have now been associated with iron disorders and/or hemochromatosis. By “exon” is meant a segment of a gene the sequence of which is represented in a mature RNA product, and by “intron” is meant a segment of a gene the sequence of which is not represented in a mature RNA product. An intron is a part of a primary nuclear transcript which is subsequently spliced out to produce a mature RNA product, i.e., a mRNA, which is then transported to the cytoplasm. A method of diagnosing an iron disorder or a genetic susceptibility to developing the disorder is carried out by determining the presence or absence of a mutation in an intron of HFE genomic DNA in a biological sample. The presence of the mutation is indicative of the disorder or a genetic susceptibility to developing the disorder. The presence of a mutation in an intron is a marker for an exon mutation, e.g., a mutation in intron 4, e.g., at nucleotide 6884 of SEQ ID NO:27 is associated with the S65C mutation in exon 2. A mutation in intron 5, e.g., at nucleotide 7055 of SEQ ID NO:27 is associated with hemochromatosis. In some cases, intron mutations may adversely affect proper splicing of exons or may alter regulatory signals. Preferably, the intron 4 mutation is 6884C and the intron 5 mutation is 7055G. To amplify nucleic acid molecule containing nucleotide 6884 or 7055, primers which flank that nucleotide, e.g., those described in Table 3, are used according to standard methods. Nucleic acid-based diagnostic methods may or may not include a step of amplification to increase the number of copies of the nucleic acid to be analyzed. To detect a mutation in intron 4, a patient-derived nucleic acid may be amplified using a first oligonucleotide primer which is 5′ to intron 4 and a second oligonucleotide primer which is 3′ to intron 4, and to detect a mutation in intron 5, the nucleic acid may be amplified using a first oligonucleotide primer which is 5′ to intron 5 and a second oligonucleotide primer which is 3′ to intron 5 (see, e.g., Table 3).
[0010] In addition to nucleic acid-based diagnostic methods, the invention includes a method of diagnosing an iron overload disorder or a genetic susceptibility thereto by determining the presence of a mutation in a HFE gene product in a biological sample. For example, the mutation results in a decrease in intramolecular salt bridge formation in the mutant HFE gene product compared to salt bridge formation in a wild type HFE gene product. The mutation which affects salt bridge formation is at or proximal to residue 63 of SEQ ID NO:2, but is not amino acid is substitution H63D. Preferably, the mutation is between residues 23-113, inclusive of SEQ ID NO:2 (Table 2), more preferably, it is between residues 90-100, inclusive, of SEQ ID NO:2, more preferably, it is between residues 58-68, inclusive, of SEQ ID NO:2, and most preferably, the mutation is amino acid substitution S65C. Alternatively, the mutation which affects salt bridge formation is a mutation, e.g., an amino acid substitution at residue 95 or proximal to residue 95 of SEQ ID NO:2. Preferably, the mutation is G93R. Such an HFE mutation is detected by immunoassay or any other ligand binding assay such as binding of the HFE gene product to a transferrin receptor. Mutations are also detected by amino acid sequencing, analysis of the structural conformation of the protein, or by altered binding to a carbohydrate or peptide mimetope.
[0011] A mutation indicative of an iron disorder or a genetic susceptibility to developing such a disorder is located in the α1 helix (e.g., which spans residues 80-108, inclusive, of SEQ ID NO:2) of an HFE gene product. The mutation may be an addition, deletion, or substitution of an amino acid in the wild type sequence. For example, the mutant HFE gene product contains the amino acid substitution I105T or G93R or in the loop of the β sheet of the HFE molecule, e.g., mutation S65C
[0012] Isolated nucleic acids encoding a mutated HFE gene products (and nucleic acids with nucleotide sequences complementary to such coding sequences) are also within the invention. Also included are nucleic acids which are at least 12 but less than 100 nucleotides in length. An isolated nucleic acid molecule is a nucleic acid molecule that is separated from the 5′ and 3′ sequences with which it is immediately contiguous in the naturally occurring genome of an organism. “Isolated” nucleic acid molecules include nucleic acid molecules which are not naturally occurring. For example, an isolated nucleic acid is one that has been amplified in vitro, e.g, by PCR; recombinantly produced; purified, e.g., by enzyme cleavage and gel separation; or chemically synthesized. For example, the restriction enzyme, Bst4C I (Sib Enzyme Limited, Novosibirsk, Russia), can be used to detect the G93R mutation (point mutation 277C); this enzyme cuts the mutated HFE nucleic acid but not the wild type HFE nucleic acid. Such nucleic acids are used as markers or probes for disease states. For example, a marker is a nucleic acid molecule containing a nucleotide polymorphism, e.g., a point mutation, associated with an iron disorder disease state flanked by wild type HFE sequences. The invention also encompasses nucleic acid molecules that hybridize, preferably under stringent conditions, to a nucleic acid molecule encoding a mutated HFE gene product (or a complementary strand of such a molecule). Preferably the hybridizing nucleic acid molecule is 400 nucleotides, more preferably 200 nucleotides, more preferably 100, more preferably 50, more preferably 25 nucleotides, more preferably 20 nucleotides, and most preferably 10-15 nucleotides, in length. For example, the nucleotide probe to detect a mutation is 13-15 nucleotides long. The nucleic acids are also used to produce recombinant peptides for generating antibodies specific for mutated HFE gene products. In preferred embodiments, an isolated nucleic acid molecule encodes an HFE polypeptide containing amino acid substitution I105T, G93R, or S65C, as well as nucleic acids the sequence of which are complementary to such nucleic acid which encode a mutant or wild type HFE gene product.
[0013] Also within the invention are substantially pure mutant HFE gene products, e.g., an HFE polypeptide containing amino acid substitution I105T, G93R, or S65C. Substantially pure or isolated HFE polypeptides include those that correspond to various functional domains of HFE or fragments thereof, e.g., a fragment of HFE that contains the α1 domain.
[0014] Wild type HFE binds to the transferrin receptor and regulates the affinity of transferrin receptor binding to transferrin. For example, a C282Y mutation in the HFE gene product reduces binding to the transferrin receptor, thus allowing the transferrin receptor to bind to transferrin (which leads to increased iron absorption).
[0015] The polypeptides of the invention encompass amino acid sequences that are substantially identical to the amino acid sequence shown in Table 2 (SEQ ID NO:2). Polypeptides of the invention are recombinantly produced, chemically synthesized, or purified from tissues in which they are naturally expressed according to standard biochemical methods of purification. Biologically active or functional polypeptides are those which possess one or more of the biological functions or activities of wild type HFE, e.g., binding to the transferrin receptor or regulation of binding of transferrin to the transferrin receptor. A functional polypeptide is also considered within the scope of the invention if it serves as an antigen for production of antibodies that specifically bind to an HFE epitope. In many cases, functional polypeptides retain one or more domains present in the naturally-occurring form of HFE.
[0016] The functional polypeptides may contain a primary amino acid sequence that has been altered from those disclosed herein. Preferably, the cysteine residues in exons 3 and 4 remain unchanged. Preferably the modifications consist of conservative amino acid substitutions. The terms “gene product”, “protein”, and “polypeptide” are used herein to describe any chain of amino acids, regardless of length or post-translational modification (for example, glycosylation or phosphorylation). Thus, the term “HFE polypeptide or gene product” includes full-length, naturally occurring HFE protein, as well a recombinantly or synthetically produced polypeptide that correspond to a full-length naturally occurring HFE or to a particular domain or portion of it.
[0017] The term “purified” as used herein refers to a nucleic acid or peptide that is substantially free of cellular material, viral material, or culture medium when produced by recombinant DNA techniques, or chemical precursors or other chemicals when chemically synthesized. Polypeptides are said to be “substantially pure” when they are within preparations that are at least 60% by weight (dry weight) the compound of interest. Preferably, the preparation is at least 75%, more preferably at least 90%, and most preferably at least 99%, by weight the compound of interest. Purity can be measured by any appropriate standard method, for example, by column chromatography, polyacrylamide gel electrophoresis, or HPLC analysis.
[0018] Diagnostic kits for identifying individuals suffering from or at risk of developing an iron disorder are also within the invention. A kit for detecting a nucleotide polymorphism associated with an iron disorder or a genetic susceptibility thereto contains an isolated nucleic acid which encodes at least a portion of the wild type or mutated HFE gene product, e.g., a portion which spans a mutation diagnostic for an iron disorder or hemochromatosis (or a nucleic acid the sequence of which is complementary to such a coding sequence). A kit for the detection of the presence of a mutation in exon 2 of an HFE nucleic acid contains a first oligonucleotide primer which is 5′ to exon 2 and a is second oligonucleotide primer is 3′ to exon 2, and a kit for an antibody-based diagnostic assay includes an antibody which preferentially binds to an epitope of a mutant HFE gene product, e.g., an HFE polypeptide containing amino acid substitution I105T, G93R, or S65C, compared to its binding to the wild type HFE polypeptide. An increase in binding of the mutant HFE-specific antibody to a patient-derived sample (compared to the level of binding detected in a wild type sample or sample derived from a known normal control individual) indicates the presence of a mutation which is diagnostic of an iron disorder, i.e., that the patient from which the sample was taken has an iron disorder or is at risk of developing one. The kit may also contain an antibody which binds to an epitope of wild type HFE which contains residue 105, 93, or 65. In the latter case, reduced binding of the antibody to a patient-derived HFE gene product (compared to the binding to a wild type HFE gene product or a gene product derived from a normal control individual) indicates the presence of a mutation which is diagnostic of an iron disorder, i.e., that the patient from which the sample was taken has an iron disorder or is at risk of developing one.
[0019] Individual mutations and combinations of mutations in the HFE gene are associated with varying severity of iron disorders. For example, the C282Y mutation in exon 4 is typically associated with clinical hemochromatosis, whereas other HFE mutations or combinations of mutations in HFE nucleic acids are associated with disorders of varying prognosis. In some cases, hemochromatosis patients have been identified which do not have a C282Y mutation. The I105T and G93R mutations are each alone associated with an increased risk of iron overload (compared to, e.g., the H63D mutation alone), and the presence of both the I105T and H63D mutation is associated with hemochromatosis. Accordingly, the invention includes a method of determining the prognosis for hemochromatosis in a mammal suffering from or at risk of developing said hemochromatosis by (a) detecting the presence or absence of a first mutation in exon 4 in each allele of an HFE nucleic acid, e.g., patient-derived chromosomal DNA, and (b) detecting the presence of a second mutation in exon 2 in each allele of the nucleic acid. The presence of the first mutation in both chromosomes, i.e. an exon 4 homozygote such as a C282Y homozygote, indicates a more negative prognosis compared to the presence of the second mutation in one or both chromosomes, i.e., an exon 2 heterozygote or homozygote. An exon 4 mutation homozygote is also associated with a more negative prognosis compared to the presence of a first mutation (exon 4) in one allele and the presence of the second mutation (exon 2) in one allele, i.e., a compound heterozygote.
[0020] Other features and advantages of the invention will be apparent from the following detailed description, and from the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0021] FIG. 1 is a diagram of the family of proband 1 (HFE genotype H63D/I105T). □=male, ●=female, ø=deceased, ▪=hemochromatosis phenotype. Proband 1 is indicated by an arrow. Phenotype and genotype data: age in year saturation; % Ftn=serum ferritin concentration. I105 separate chromosomes. The sister of the proband (II, 203) has hyperferritinemia.
[0022] FIG. 2 is a diagram of the family of proband 2 (HFE genotype C282Y/G93R). Symbols and abbreviations are the same as those described for FIG. 1 . Proband 2 is indicated with an arrow. G93R, C282Y, and wt alleles are known to exist only on separate chromosomes. The father and sister of the proband are being treated for hemochromatosis.
[0023] FIG. 3 is a diagram of the family of proband 3 (HFE genotype C282Y/S65C). Symbols and abbreviations are the same as those described for FIG. 1 . Proband 3 is indicated with an arrow. S65C, C282Y, and wt alleles are know to exist only on separate chromosomes. Proband 3 also has porphyria cutanea tarda, and her brother (II, 203) has ankylosing spondylitis.
DETAILED DESCRIPTION
[0024] A proband is the first individual in a family identified to be affected by hemochromatosis. Forward and reverse sequencing of HFE exons 2, 3, 4, and 5, and of portions of HFE introns 2, 4, and 5 was carried out on biological samples taken from twenty hemochromatosis probands who lacked C282Y homozygosity, C282Y/H63D compound heterozygosity, or H63D homozygosity. Four probands had novel HFE coding region mutations. Probands 1 and 2 were heterozygous for previously undescribed mutations: exon 2, nt 314T→C (314C; I105T), and exon 2, nt 277G→C (277C; G93R), respectively; these probands were also heterozygous for H63D and C282Y, respectively. Probands 3 and 4 were heterozygous for an HFE mutation in exon 2, nt 193A→T (193T; S65C). Twelve other probands did not have an exon 2 HFE exon mutation; four were heterozygous for H63D. In probands 1, 2, 3, and 4, the amino acid substitutions I105T, G93R, and S65C (respectively) occurred on separate chromosomes from those with the C282Y or H63D mutations. In 176 normal control subjects, two were heterozygous for S65C; I105T and G93R were not detected in controls. Nine probands were heterozygous and two probands were homozygous for a base-pair change at intron 2, nt 4919T/C (SEQ ID NO:27). Heterozygosity for a base-pair change in intron 4 (nt 6884T→C) was detected only in probands 3 and 4, both of whom also had S65C and HLA-A32. The intron 2 mutation is not diagnostic of an iron disorder and appears randomly in the population. One proband was heterozygous for a base-pair change at intron 5 (nt 7055A→G).
[0025] The data described herein indicate that, in addition to the C282Y and H63D HFE mutations, the HFE exon and intron 5 mutations described herein are diagnostic (and prognostic) of iron disorders.
[0000] Pathology of Iron Overload
[0026] Iron plays an essential role in normal growth and development, but in elevated concentrations, iron is a toxic inorganic molecule and is the leading cause of death in children by poisoning. It has been implicated in the pathophysiology of a number of common diseases, e.g., hepatitis, cancer, heart disease, reperfusion injury, rheumatoid arthritis, diabetes, AIDS, and psychological abnormalities (e.g. depression).
[0027] The incidence of cancer (especially liver cancer) rises dramatically in the course of hemochromatosis. Iron, acting alone or in synergy with other environmental agents, catalyzes free radical formation. These free radicals which mediate tissue damage also cause DNA double strand breaks and oncogene activation. Iron may also play a role in the pathogenesis of rheumatic diseases and in predisposition to heart disease. High levels of iron can also cause diabetes with 2% of diabetics being hemochromatosis patients. High levels of iron may also affect the disease progression of many viral diseases. Individuals infected with such viruses as hepatitis (e.g., hepatitis B or C) or HIV should be tested for HFE mutations because of the impact increased iron stores have on the treatment and prognosis of such diseases.
[0028] Excessive iron stores and iron deposition is also a major contributing factor in the pathology and treatment of non-valvular heart disease. These conditions include dilated cardiomyopathy cased by deposition of iron in myocardial fibers; myocardial injury the product of anthracycline cardiomyopathy and re-perfusion injury. Increased iron stores may also be a contributing factor in myocardial infarction due to atherosclerosis. Some evidence suggests a significant increase in the incidence of reported heart disease in probands (cardiac symptoms-32%, insulin-dependent diabetes-18%, cardiac arrhythmia-17%, clinically significant coronary artery atherosclerosis-9%, and congestive heart failure-7%. Cardiac complications have been detected in 30% of patients. These include EKG abnormalities, congestive heart failure and cardiac arrhythmias. An increased frequency of HFE mutations in individuals with porphyria cutanea tarda indicates that HFE mutations may predipose an individual to developing this syndrome.
[0029] The effect of iron overload is irreparable damage to vital organs and a multiplicity of associated pathologies described above. The multiplicity of clinical symptoms (and associated pathologies) often causes misdiagnosis of hemochromatosis or failure to diagnose hemochromatosis.
[0030] Untreated hemochromatosis is characterized by iron overload of parenchymal cells, which is toxic and the probable cause of various complications including cirrhosis, and liver cancer, arthropathy, hypogonadotropic hypogonadism, marrow aplasia, skin disorders, diabetes mellitus, and cardiomyopathy. There are 1.5 to 2 million active cases in the U.S. of which 40% have progressive liver disease because they have not been properly diagnosed or treated.
[0031] In untreated hemochromatosis, iron is universally deposited in the hepatocytes of the liver. The iron is found primarily in the cytoplasm of hepatocytes, and by electron microscopy in lysosomal vacuoles, and in more severe cases iron has also been reported deposited in mitochondria. Other liver toxins such as alcohol, and hepatitis exacerbate the damage caused by the iron deposition. Patients with hemochromatosis are advised not to drink, because of increased liver damage, or to smoke, as iron deposition can also occur in the lungs.
[0032] Individuals which are homozygous (and to a lesser extent heterozygous) for an HFE mutation are at risk for developing increased levels of blood lead. Thus, it is important to identify heterozygous as well as homozygous patients.
[0033] Identification and detection of mutations in the HFE gene are critical to understanding the general mechanisms of iron disorders and diagnosing iron-related pathologies.
[0000] Nucleic Acid-Based Assays for HFE Mutations
[0034] A biological sample containing RNA or DNA is obtained from an individual and the nucleic acid extracted. Optionally, the nucleic acid is amplified according to standard procedures such as PCR. A nucleic acid polymorphism, e.g, a single base pair polymorphism, is detected using methods well known in the art of molecular biology. For example, a mutation is detected using a standard sequencing assay, nucleic acid hybridization, e.g, using standard Southern, Northern, or dot blot hybridization assay systems and an HFE-specific oligonucleotide probe, restriction enzyme fragment polymorphism analysis, oligonucleotide ligation assay (OLA; Nikerson et al., 1990, Nucl. Acids Res. 87:8923-8927), primer extension analysis (Nikiforov et al., 1994, Nucl. Acids Res. 22:4167-4175), single strand conformation polymorphism (SSCP) analysis, allele-specific PCR (Rust et al., 1993, Nucl. Acids Res. 6:3623-3629), denaturing gradient gel electrophoresis (DGGE), fluorescent probe melting curve analysis (Bernard et al., 1998, Am. J. Pathol. 153:1055-61), RNA mismatch cleavage assay, capillary hybridization, or TaqMan™ assay (PE Applied Biosystems, Foster City, Calif.). Nucleic acid hybridization assays are also carried out using a bioelectronic microchip technology known in the art, e.g., that described in Sosnowski et al., 1997, Proc. Natl. Acad. Sci. U.S.A. 94:1119-1123; Cheng et al. 1998, Nature Biotechnology 16:541-546; or Edman et al., 1997, Nucl. Acids Res. 25:4907-4914.
[0000] Detection of Mutations Using Antibodies and Other HFE Ligands
[0035] Anti-HFE antibodies are know in the art, e.g., those described by Feder et al., 1997, J. Biol. Chem. 272:14025-14028, or are obtained using standard techniques. Such antibodies can be polyclonal or monoclonal. Polyclonal antibodies can be obtained, for example, by the methods described in Ghose et al., Methods in Enzymology, Vol. 93, 326-327, 1983. An HFE polypeptide, or an antigenic fragment thereof, is used as an immunogen to stimulate the production of HFE-reactive polyclonal antibodies in the antisera of animals such as rabbits, goats, sheep, rodents and the like. HFE antibodies specific for mutated HFE gene products are raised by immunizing animals with a polypeptide spanning the mutation, e.g, a polypeptide which contains the mutations described herein. For example, the entire α1 domain of a mutant HFE gene product is used as an immunogen. Monoclonal antibodies are obtained by the process described by Milstein and Kohler in Nature, 256:495-97, 1975, or as modified by Gerhard, Monoclonal Antibodies, Plenum Press, 1980, pages 370-371. Hybridomas are screened to identify those producing antibodies that are highly specific for an HFE polypeptide containing a mutation characteristic of an iron metabolism abnormality or clinical hemochromatosis. Preferably, the antibody has an affinity of at least about 10 5 liters/mole, preferably at least 106 liters/mole, more preferably at least 108 liters/mole, and most preferably, an affinity of at least about 10 9 liters/mole.
[0036] Antibodies specific for the wild type HFE can also be used to diagnose hemochromatosis or iron metabolism abnormalities. Such antibodies are also useful research tools to identify novel mutations indicative of iron disorders or hemochromatosis. A reduction in binding to a wild type HFE-specific antibody indicates the presence of a mutation. Antibody binding is detected using known methods. For example, an ELISA assay involves coating a substrate, e.g., a plastic dish, with an antigen, e.g., a patient-derived biological sample containing an HFE gene product. An antibody preparation is then added to the well. Antibodies specific for a mutant HFE gene product bind or fail to bind to a patient-derived sample in the well. Non-binding material is washed away and a marker enzyme e.g., horse radish peroxidase or alkaline phosphatase, coupled to a second antibody directed against the antigen-specific primary antibody is added in excess and the nonadherent material is washed away. An enzyme substrate is added to the well and the enzyme catalyzed conversion is monitored as is indicative of presence of the mutation. Antibodies are also labelled with various sizes of colloidal gold particles or latex particles for detection of binding.
[0037] The invention employs not only intact monoclonal or polyclonal antibodies, but also an immunologically-active antibody fragment, for example, a Fab or (Fab) 2 fragment; an antibody heavy chain, an antibody light chain; a genetically engineered single-chain Fv molecule (Ladner et al., U.S. Pat. No. 4,946,778).
EXAMPLE 1
Selection and Characterization of Subjects
[0038] All individuals studied were Caucasians, 18 years of age or older, and from central Alabama. Twenty probands were identified that were either heterozygous for C282Y or H63D, or lacked these mutations. Hemochromatosis is typically diagnosed by detecting elevated saturation of transferrin, with elevated serum ferritin levels, combined with liver biopsy. Each proband patient described below was previously diagnosed to have hemochromatosis by the working diagnostic criterion for hemochromatosis of the American College of Pathologists (elevated fasting transferrin saturation of greater than 60% saturation for males and greater than 50% saturation for females) on at least two occasions in the absence of other known causes. Probands were interviewed regarding their general medical history, diet (including estimated iron content and ethanol consumption), medicinal iron use, receipt of blood transfusion, prior significant hemorrhage, blood donation for transfusion and/or therapeutic phlebotomy, and pregnancy and lactation. Each proband was also evaluated for viral hepatitis B and C and other hepatic disorders, excess ethanol intake, and hereditary, and acquired anemia. Iron overload was defined as evidence of systemic iron overload demonstrated by otherwise unexplained elevated serum is ferritin concentration (≧300 ng/mL in men, ≧200 ng/mL in women), increased hepatic iron content determined using hepatic biopsy specimens, or iron >4 g mobilized by phlebotomy. Complications of iron overload were evaluated and treated, and therapeutic phlebotomy was performed using standard methods. HFE mutation analysis for C282Y and H63D and human leukocyte antigen (HLA) immunophenotyping or molecular typing were performed using known methods. In some family members, HLA haplotyping had been performed previously for other disease associations, or their HLA type could be deduced from analysis of their kinship and HFE genotyping results. Measurement of serum iron and other clinical laboratory parameters and analysis of hepatic biopsy specimens were performed using routine methods. Control subjects (n=176) who were in apparently good health and were unrelated to the hemochromatosis probands were recruited from the general population. Iron parameters were measured and HLA typing was performed in two control subjects after HFE genotyping revealed that they had the S65C mutation.
EXAMPLE 2
HFE Gene Analysis
[0039] PCR amplification was used to detect mutations. Genomic DNA was prepared from peripheral blood buffy coat or saliva using the QIAmpBlood Kit (QIAGEN, Valencia, Calif.) or FTA Paper and FTA purification reagent (Fitzco Inc., Maple Plain, Minn.), respectively. Fragments were amplified from genomic DNA using eLONGase (Life Technologies, Gaithersburg, Md.) or HotStarTaq DNA polymerase (QIAGEN, Valencia, Calif.). Primers used to amplify each exon are shown in Table 3.
TABLE 4 Human HFE genomic DNA 1 ggatccttta accgaggaga ttattatagc cggagctctg aagcagcaat ctcagttctt 61 gtgatagtga gcaaagaact acaaactaac accaaaatgc aagcttaaag caaagtttat 121 tgaagcacaa taatacactc tgagggacag cgggcttatt tctgcgaagt gaactcagca 181 cttctttaca gagctcaagg tgcttttatg gggtttgtgg ggaggagttg aggtttgggc 241 tgtatctgag tgacaggatg atgttatttg attgaagttt atagctatac aatctaaaat 301 taaactgtgc atggtcttac ctataatttg ttaagaaaag cctcccaggg atgggggggc 361 aaaactgtat gtaaattcta ttataatgat ggcatgatga acttggggtg aacttgaaga 421 caggcttttg tgttgttggg catgtgccac cttagggaat ttccacctgt accctccttt 481 ctctttctcc aggatatttt ggccacagac tttatcataa actccatccc ttagggtggc 541 attagggtag tcttgggcct gaatttaggt gggccagtgg ctgtcttagt gacagccttt 601 ccgctctctt ctgtcatccc ctcccaactg ctaatgtcta actacctaac aattacccat 661 taaatcagtg tgtctggggt taggagcagg cctcaatatg tttaatcatt ctccagataa 721 tcccaatact gtaaagtttg tgaaacactt gtcagataat tcaattatga aggctgtgga 781 acgtgtttca gtaggatcta attggttaat gttatgactt aattaatttg aatcaaaaaa 841 caaaatgaaa aagctttata tttctaagtc aaataagaca taagttggtc taaggttgag 901 ataaaatttt taaatgtatg attgaatttt gaaaatcata aatatttaaa tatctaaagt 961 tcagatcaga acattgcgaa gctactttcc ccaatcaaca acaccccttc aggatttaaa 1021 aaccaagggg gacactggat cacctagtgt ttcacaagca ggtaccttct gctgtaggag 1081 agagagaact aaagttctga aagacctgtt gcttttcacc aggaagtttt actgggcatc 1141 tcctgagcct aggcaatagc tgtagggtga cttctggagc catccccgtt tccccgcccc 1201 ccaaaagaag cggagattta acggggacgt gcggccagag ctggggaaat gggcccgcga 1261 gccaggccgg cgcttctcct cctgatgctt ttgcagaccg cggtcctgca ggggcgcttg 1321 ctgcgtgagt ccgagggctg cgggcgaact aggggcgcgg cgggggtgga aaaatcgaaa 1381 ctagcttttt ctttgcgctt gggagtttgc taactttgga ggacctgctc aacccaatcc 1441 gcaagcccct ctccctactt tctgcgtcca gaccccgtga gggagtgcct accactgaac 1501 tgcagatagg ggtccctcgc cccaggacct gccccctccc ccggctgtcc cggctctgcg 1561 gagtgacttt tggaaccgcc cactcccttc ccccaactag aatgctttta aataaatctc 1621 gtagttcctc acttgagccg agctaagcct ggggctcctt gaacctggaa ctcgggttta 1681 tttccaatgt cagctgtgca gttttttccc cagtcatctc caaacaggaa gttcttccct 1741 gagtgcttgc cgagaaggct gagcaaaccc acagcaggat ccgcacgggg tttccacctc 1801 agaacgaatg cgttgggcgg tgggggcgcg aaagagtggc gttggggatc tgaattcttc 1861 accattccac ccacttttgg tgagacctgg ggtggaggtc tctagggtgg gaggctcctg 1921 agagaggcct acctcgggcc tttccccact cttggcaatt gttcttttgc ctggaaaatt 1981 aagtatatgt tagttttgaa cgtttgaact gaacaattct cttttcggct aggctttatt 2041 gatttgcaat gtgctgtgta attaagaggc ctctctacaa agtactgata atgaacatgc 2101 aagcaatgca ctcacttcta agttacattc atatctgatc ttatttgatt ttcactaggc 2161 atagggaggt aggagctaat aatacgttta ttttactaga agttaactgg aattcagatt 2221 atataactct tttcaggtta caaagaacat aaataatctg gttttctgat gttatttcaa 2281 gtactacagc tgcttctaat cttagttgac agtgattttg ccctgtagtg tagcacagtg 2341 ttctgtgggt cacacgccgg cctcagcaca gcactttgag ttttggtact acgtgtatcc 2401 acattttaca catgacaaga atgaggcatg gcacggcctg cttcctggca aatttattca 2461 atggtacacg gggctttggt ggcagagctc atgtctccac ttcatagcta tgattcttaa 2521 acatcacact gcattagagg ttgaataata aaatttcatg ttgagcagaa atattcattg 2581 tttacaagtg taaatgagtc ccagccatgt gttgcactgt tcaagcccca agggagagag 2641 cagggaaaca agtctttacc ctttgatatt ttgcattcta gtgggagaga tgacaataag 2701 caaatgagca gaaagatata caacatcagg aaatcatggg tgttgtgaga agcagagaag 2761 tcagggcaag tcactctggg gctgacactt gagcagagac atgaaggaaa taagaatgat 2821 attgactggg agcagtattt cccaggcaaa ctgagtgggc ctggcaagtt ggattaaaaa 2881 gcgggttttc tcagcactac tcatgtgtgt gtgtgtgggg gggggggcgg cgtgggggtg 2941 ggaaggggga ctaccatctg catgtaggat gtctagcagt atcctgtcct ccctactcac 3001 taggtgctag gagcactccc ccagtcttga caaccaaaaa tgtctctaaa ctttgccaca 3061 tgtcacctag tagacaaact cctggttaag aagctcgggt tgaaaaaaat aaacaagtag 3121 tgctggggag tagaggccaa gaagtaggta atgggctcag aagaggagcc acaaacaagg 3181 ttgtgcaggc gcctgtaggc tgtggtgtga attctagcca aggagtaaca gtgatctgtc 3241 acaggctttt aaaagattgc tctggctgct atgtggaaag cagaatgaag ggagcaacag 3301 taaaagcagg gagcccagcc aggaagctgt tacacagtcc aggcaagagg tagtggagtg 3361 ggctgggtgg gaacagaaaa gggagtgaca aaccattgtc tcctgaatat attctgaagg 3421 aagttgctga aggattctat gttgtgtgag agaaagagaa gaattggctg ggtgtagtag 3481 ctcatgccaa ggaggaggcc aaggagagca gattcctgag ctcaggagtt caagaccagc 3541 ctgggcaaca cagcaaaacc ccttctctac aaaaaataca aaaattagct gggtgtggtg 3601 gcatgcacct gtgatcctag ctactcggga ggctgaggtg gagggtattg cttgagccca 3661 ggaagttgag gctgcagtga gccatgactg tgccactgta cttcagccta ggtgacagag 3721 caagaccctg tctcccctga ccccctgaaa aagagaagag ttaaagttga ctttgttctt 3781 tattttaatt ttattggcct gagcagtggg gtaattggca atgccatttc tgagatggtg 3841 aaggcagagg aaagagcagt ttggggtaaa tcaaggatct gcatttggac atgttaagtt 3901 tgagattcca gtcaggcttc caagtggtga ggccacatag gcagttcagt gtaagaattc 3961 aggaccaagg cagggcacgg tggctcactt ctgtaatccc agcactttgg tggctgaggc 4021 aggtagatca tttgaggtca ggagtttgag acaagcttgg ccaacatggt gaaaccccat 4081 gtctactaaa aatacaaaaa ttagcctggt gtggtggcgc acgcctatag tcccaggttt 4141 tcaggaggct taggtaggag aatcccttga acccaggagg tgcaggttgc agtgagctga 4201 gattgtgcca ctgcactcca gcctgggtga tagagtgaga ctctgtctca aaaaaaaaaa 4261 aaaaaaaaaa aaaaaaaaaa aactgaagga attattcctc aggatttggg tctaatttgc 4321 cctgagcacc aactcctgag ttcaactacc atggctagac acaccttaac attttctaga 4381 atccaccagc tttagtggag tctgtctaat catgagtatt ggaataggat ctgggggcag 4441 tgagggggtg gcagccacgt gtggcagaga aaagcacaca aggaaagagc acccaggact 4501 gtcatatgga agaaagacag gactgcaact cacccttcac aaaatgagga ccagacacag 4561 ctgatggtat gagttgatgc aggtgtgtgg agcctcaaca tcctgctccc ctcctactac 4621 acatggttaa ggcctgttgc tctgtctcca ggttcacact ctctgcacta cctcttcatg 4681 ggtgcctcag agcaggacct tggtctttcc ttgtttgaag ctttgggcta cgtggatgac 4741 cagctgttcg tgttctatga tcatgagagt cgccgtgtgg agccccgaac tccatgggtt 4801 tccagtagaa tttcaagcca gatgtggctg cagctgagtc agagtctgaa agggtgggat 4861 cacatgttca ctgttgactt ctggactatt atggaaaatc acaaccacag caagggtatg 4921 tggagagggg gcctcacctt cctgaggttg tcagagcttt tcatcttttc atgcatcttg 4981 aaggaaacag ctggaagtct gaggtcttgt gggagcaggg aagagggaag gaatttgctt 5041 cctgagatca tttggtcctt ggggatggtg gaaataggga cctattcctt tggttgcagt 5101 taacaaggct ggggattttt ccagagtccc acaccctgca ggtcatcctg ggctgtgaaa 5161 tgcaagaaga caacagtacc gagggctact ggaagtacgg gtatgatggg caggaccacc 5221 ttgaattctg ccctgacaca ctggattgga gagcagcaga acccagggcc tggcccacca 5281 agctggagtg ggaaaggcac aagattcggg ccaggcagaa cagggcctac ctggagaggg 5341 actgccctgc acagctgcag cagttgctgg agctggggag aggtgttttg gaccaacaag 5401 gtatggtgga aacacacttc tgcccctata ctctagtggc agagtggagg aggttgcagg 5461 gcacggaatc cctggttgga gtttcagagg tggctgaggc tgtgtgcctc tccaaattct 5521 gggaagggac tttctcaatc ctagagtctc taccttataa ttgagatgta tgagacagcc 5581 acaagtcatg ggtttaattt cttttctcca tgcatatggc tcaaagggaa gtgtctatgg 5641 cccttgcttt ttatttaacc aataatcttt tgtatattta tacctgttaa aaattcagaa 5701 atgtcaaggc cgggcacggt ggctcacccc tgtaatccca gcactttggg aggccgaggc 5761 gggtggtcac aaggtcagga gtttgagacc agcctgacca acatggtgaa acccgtctct 5821 aaaaaaatac aaaaattagc tggtcacagt catgcgcacc tgtagtccca gctaattgga 5881 aggctgaggc aggagcatcg cttgaacctg ggaagcggaa gttgcactga gccaagatcg 5941 cgccactgca ctccagccta ggcagcagag tgagactcca tcttaaaaaa aaaaaaaaaa 6001 aaaaagagaa ttcagagatc tcagctatca tatgaatacc aggacaaaat atcaagtgag 6061 gccacttatc agagtagaag aatcctttag gttaaaagtt tctttcatag aacatagcaa 6121 taatcactga agctacctat cttacaagtc cgcttcttat aacaatgcct cctaggttga 6181 cccaggtgaa actgaccatc tgtattcaat cattttcaat gcacataaag ggcaatttta 6241 tctatcagaa caaagaacat gggtaacaga tatgtatatt tacatgtgag gagaacaagc 6301 tgatctgact gctctccaag tgacactgtg ttagagtcca atcttaggac acaaaatggt 6361 gtctctcctg tagcttgttt ttttctgaaa agggtatttc cttcctccaa cctatagaag 6421 gaagtgaaag ttccagtctt cctggcaagg gtaaacagat cccctctcct catccttcct 6481 ctttcctgtc aagtgcctcc tttggtgaag gtgacacatc atgtgacctc ttcagtgacc 6541 actctacggt gtcgggcctt gaactactac ccccagaaca tcaccatgaa gtggctgaag 6601 gataagcagc caatggatgc caaggagttc gaacctaaag acgtattgcc caatggggat 6661 gggacctacc agggctggat aaccttggct gtaccccctg gggaagagca gagatatacg 6721 tgccaggtgg agcacccagg cctggatcag cccctcattg tgatctgggg tatgtgactg 6781 atgagagcca ggagctgaga aaatctattg ggggttgaga ggagtgcctg aggaggtaat 6841 tatggcagtg agatgaggat ctgctctttg ttaggggatg ggctgagggt ggcaatcaaa 6901 ggctttaact tgctttttct gttttagagc cctcaccgtc tggcacccta gtcattggag 6961 tcatcagtgg aattgctgtt tttgtcgtca tcttgttcat tggaattttg ttcataatat 7021 taaggaagag gcagggttca agtgagtagg aacaaggggg aagtctctta gtacctctgc 7081 cccagggcac agtgggaaga ggggcagagg ggatctggca tccatgggaa gcatttttct 7141 catttatatt ctttggggac accagcagct ccctgggaga cagaaaataa tggttctccc 7201 cagaatgaaa gtctctaatt caacaaacat cttcagagca cctactattt tgcaagagct 7261 gtttaaggta gtacaggggc tttgaggttg agaagtcact gtggctattc tcagaaccca 7321 aatctggtag ggaatgaaat tgatagcaag taaatgtagt taaagaagac cccatgaggt 7381 cctaaagcag gcaggaagca aatgcttagg gtgtcaaagg aaagaatgat cacattcagc 7441 tggggatcaa gatagccttc tggatcttga aggagaagct ggattccatt aggtgaggtt 7501 gaagatgatg ggaggtctac acagacggag caaccatgcc aagtaggaga gtataaggca 7561 tactgggaga ttagaaataa ttactgtacc ttaaccctga gtttgcttag ctatcactca 7621 ccaattatgc atttctaccc cctgaacatc tgtggtgtag ggaaaagaga atcagaaaga 7681 agccagctca tacagagtcc aagggtcttt tgggatattg ggttatgatc actggggtgt 7741 cattgaagga tcctaagaaa ggaggaccac gatctccctt atatggtgaa tgtgttgtta 7801 agaagttaga tgagaggtga ggagaccagt tagaaagcca ataagcattt ccagatgaga 7861 gataatggtt cttgaaatcc aatagtgccc aggtctaaat tgagatgggt gaatgaggaa 7921 aataaggaag agagaagagg caagatggtg cctaggtttg tgatgcctct ttcctgggtc 7981 tcttgtctcc acaggaggag ccatggggca ctacgtctta gctgaacgtg agtgacacgc 8041 agcctgcaga ctcactgtgg gaaggagaca aaactagaga ctcaaagagg gagtgcattt 8101 atgagctctt catgtttcag gagagagttg aacctaaaca tagaaattgc ctgacgaact 8161 ccttgatttt agccttctct gttcatttcc tcaaaaagat ttccccattt aggtttctga 8221 gttcctgcat gccggtgatc cctagctgtg acctctcccc tggaactgtc tctcatgaac 8281 ctcaagctgc atctagaggc ttccttcatt tcctccgtca cctcagagac atacacctat 8341 gtcatttcat ttcctatttt tggaagagga ctccttaaat ttgggggact tacatgattc 8401 attttaacat ctgagaaaag ctttgaaccc tgggacgtgg ctagtcataa ccttaccaga 8461 tttttacaca tgtatctatg cattttctgg acccgttcaa cttttccttt gaatcctctc 8521 tctgtgttac ccagtaactc atctgtcacc aagccttggg gattcttcca tctgattgtg 8581 atgtgagttg cacagctatg aaggctgtac actgcacgaa tggaagaggc acctgtccca 8641 gaaaaagcat catggctatc tgtgggtagt atgatgggtg tttttagcag gtaggaggca 8701 aatatcttga aaggggttgt gaagaggtgt tttttctaat tggcatgaag gtgtcataca 8761 gatttgcaaa gtttaatggt gccttcattt gggatgctac tctagtattc cagacctgaa 8821 gaatcacaat aattttctac ctggtctctc cttgttctga taatgaaaat tatgataagg 8881 atgataaaag cacttacttc gtgtccgact cttctgagca cctacttaca tgcattactg 8941 catgcacttc ttacaataat tctatgagat aggtactatt atccccattt cttttttaaa 9001 tgaagaaagt gaagtaggcc gggcacggtg gctcacgcct gtaatcccag cactttggga 9061 ggccaaagcg ggtggatcac gaggtcagga gatcgagacc atcctggcta acatggtgaa 9121 accccatctc taataaaaat acaaaaaatt agctgggcgt ggtggcagac gcctgtagtc 9181 ccagctactc ggaaggctga ggcaggagaa tggcatgaac ccaggaggca gagcttgcag 9241 tgagccgagt ttgcgccact gcactccagc ctaggtgaca gagtgagact ccatctcaaa 9301 aaaataaaaa taaaaataaa aaaatgaaaa aaaaaagaaa gtgaagtata gagtatctca 9361 tagtttgtca gtgatagaaa caggtttcaa actcagtcaa tctgaccgtt tgatacatct 9421 cagacaccac tacattcagt agtttagatg cctagaataa atagagaagg aaggagatgg 9481 ccttctcttc gtctcattgt gtttcttctg aatgagcttg aatcacatga aggggaacag 9541 cagaaaacaa ccaactgatc ctcagctgtc atgtttcctt taaaagtccc tgaaggaagg 9601 tcctggaatg tgactccctt gctcctctgt tgctctcttt ggcattcatt tctttggacc 9661 ctacgcaagg actgtaattg gtggggacag ctagtggccc tgctgggctt cacacacggt 9721 gtcctcccta ggccagtgcc tctggagtca gaactctggt ggtatttccc tcaatgaagt 9781 ggagtaagct ctctcatttt gagatggtat aatggaagcc accaagtggc ttagaggatg 9841 cccaggtcct tccatggagc cactggggtt ccggtgcaca ttaaaaaaaa aatctaacca 9901 ggacattcag gaattgctag attctgggaa atcagttcac catgttcaaa agagtctttt 9961 tttttttttt gagactctat tgcccaggct ggagtgcaat ggcatgatct cggctcactg 10021 taacctctgc ctcccaggtt caagcgattc tcctgtctca gcctcccaag tagctgggat 10081 tacaggcgtg caccaccatg cccggctaat ttttgtattt ttagtagaga cagggtttca 10141 ccatgttggc caggctggtc tcgaactctc ctgacctcgt gatccgcctg cctcggcctc 10201 ccaaagtgct gagattacag gtgtgagcca ccctgcccag ccgtcaaaag agtcttaata 10261 tatatatcca gatggcatgt gttcacttta tgttactaca tgcacttggc tgcataaatg 10321 tggtacaagc attctgtctt gaagggcagg tgcttcagga taccatatac agctcagaag 10381 tttcttcttt aggcattaaa ttttagcaaa gatatctcat ctcttctttt aaaccatttt 10441 ctttttttgt ggttagaaaa gttatgtaga aaaaagtaaa tgtgatttac gctcattgta 10501 gaaaagctat aaaatgaata caattaaagc tgttatttaa ttagccagtg aaaaactatt 10561 aacaacttgt ctattacctg ttagtattat tgttgcatta aaaatgcata tactttaata 10621 aatgtacatt gtattgtata ctgcatgatt ttattgaagt tcttgttcat cttgtgtata 10681 tacttaatcg ctttgtcatt ttggagacat ttattttgct tctaatttct ttacattttg 10741 tcttacggaa tattttcatt caactgtggt agccgaatta atcgtgtttc ttcactctag 10801 ggacattgtc gtctaagttg taagacattg gttattttac cagcaaacca ttctgaaagc 10861 atatgacaaa ttatttctct cttaatatct tactatactg aaagcagact gctataaggc 10921 ttcacttact cttctacctc ataaggaata tgttacaatt aatttattag gtaagcattt 10981 gttttatatt ggttttattt cacctgggct gagatttcaa gaaacacccc agtcttcaca 11041 gtaacacatt tcactaacac atttactaaa catcagcaac tgtggcctgt taattttttt 11101 aatagaaatt ttaagtcctc attttctttc ggtgtttttt aagcttaatt tttctggctt 11161 tattcataaa ttcttaaggt caactacatt tgaaaaatca aagacctgca ttttaaattc 11221 ttattcacct ctggcaaaac cattcacaaa ccatggtagt aaagagaagg gtgacacctg 11281 gtggccatag gtaaatgtac cacggtggtc cggtgaccag agatgcagcg ctgagggttt 11341 tcctgaaggt aaaggaataa agaatgggtg gaggggcgtg cactggaaat cacttgtaga 11401 gaaaagcccc tgaaaatttg agaaaacaaa caagaaacta cttaccagct atttgaattg 11461 ctggaatcac aggccattgc tgagctgcct gaactgggaa cacaacagaa ggaaaacaaa 11521 ccactctgat aatcattgag tcaagtacag caggtgattg aggactgctg agaggtacag 11581 gccaaaattc ttatgttgta ttataataat gtcatcttat aatactgtca gtattttata 11641 aaacattctt cacaaactca cacacattta aaaacaaaac actgtctcta aaatccccaa 11701 atttttcata aactcagttt taaactaact ttttttcaaa ccacaatctg atttaacaat 11761 gactatcatt taaatatttc tgactttcaa attaaagatt ttcacatgca ggctgatatt 11821 tgtaattgtg attctctctg taggctttgg gtataatgtg ttcttttcct tttttgcatc 11881 agcgattaac ttctacactc taacatgtag aatgttacta caatattaaa gtattttgta 11941 tgacaatttt atttgaaagc ctaggatgcg ttgacatcct gcatgcattt attacttgat 12001 atgcatgcat tctggtatct caagcattct atttctgagt aattgtttaa ggtgtagaag 12061 agatagatat ggtggatttg gagttgatac ttatatattt tctatttctt ggatggatga 12121 atttgtacat taaaagtttt ccatgg (SEQ ID NO:27; GENBANK ® Accession No. Z92910)
[0040] Exon 1 spans nt 1028-1324, inclusive; exon 2 spans nt 4652-4915, inclusive; exon 3 spans nt 5125-5400, inclusive; exon 4 spans nt 6494-6769, inclusive; exon 5 spans nt 6928-7041, inclusive; exon 6 spans nt 7995-9050, inclusive, and exon 7 spans nt 10206-10637, inclusive. Intron 4 spans nt 6770-6927, inclusive, and intron 5 spans nt 7042-7994, inclusive.
[0041] Total RNA for the RT-PCR was prepared from 1.5 mL of whole blood using the RNeasy Blood Kit (QIAGEN, Valencia, CA). Total messenger RNA encoding the HFE gene was transcribed and amplified with the primers shown above using standard methods, e.g., the Superscript ONE-STEP RT-PCR System (Life Technologies, Gaithersburg, Md.). The amplified product was directly subcloned into the pCR2.1-TOPO vector and transfected into TOP 10 bacteria (Invitrogen, Carlsbad, Calif.). Plasmid DNAs isolated from the subcloning were prepared with the UltraClean Mini Prep Kit (Mo Bio, Solana Beach, Calif.) and sequenced.
[0042] DNA sequencing was performed using the ABI Prism BigDye Terminator Cycle Sequencing Ready Reaction Kit (PE Applied Biosystems, Foster City, Calif.) and analyzed on an ABI Prism 377.
[0043] To detect mutations in exon 2 of the HFE gene, the genomic DNA of probands and normal control subjects were amplified and subjected to a dot blot hybridization assay. 1.0 μl of each resulting PCR product was then applied to a Magna Graph nylon membrane (MSI, Westboro, Mass.). The membranes were treated with 0.5 N NaOH/1.5 M NaCl to denature the DNA, neutralized with 0.5 M Tris-HCl (pH 8.0)/1.5 M NaCl, and rinsed with 2×SSC (1×SSC=0.15 M NaCl/0.015 M sodium citrate, pH 7.0). The DNAs were fixed on the membrane by UV irradiation using a Stratalinker 1800 (Stratagene, Inc., La Jolla, Calif.). The ECL 3′-oligolabelling and detection system (Amersham, Arlington Heights, Ill.) was used for synthesis of labeled oligonucleotide probes, hybridization, and signal detection. The oligonucleotide sequences used to detect each point mutation were (substituted bases are shown as upper case letters):
TABLE 5 Oligonucleotide Probes Point Mutation Oligonucleotide G93R mutation gtctgaaaCggtgggat (SEQ ID NO:28) I105T mutation acttctggactaCtatgg (SEQ ID NO:29) S65C mutation atcatgagTgtcgccgt (SEQ ID NO:30)
[0044] For signal detection, each oligonucleotide was labeled with fluorescein-11-dUTP using terminal deoxynucleotidyl transferase according to the manufacturer's instructions (Amersham Ltd., Arlington Heights, Ill.). The membranes were prehybridized in 5×SSC, 0.1% Hybridization buffer component, 0.02% SDS, 5% LiquidBlock at 42° C. for approximately 2 hours. Labelled oligonucleotide probes were added to individual bags containing the membranes and prehybridization buffer and incubated at 42° C. overnight. The blots were washed twice with 5×SSC, 0.1% SDS for 5 minutes at room temperature. Stringency washes for hybridization with oligonucleotides having the sequence of SEQ ID NO: 30 or 28 were performed twice in 0.2×SSC/0.1% SDS for 15 minutes at 42° C. Membranes probed with an oligonucleotide having the sequence of SEQ ID NO:29 was washed twice under less stringent conditions (0.5×SSC/0.1% SDS, 15 minutes at 42° C.). Detection of a fluorescent signal was performed according to standard methods.
EXAMPLE 3
Characterization of Probands
[0045] The mean age of the twenty probands was 44±11 years (range 27-62 years); thirteen (65.0%) were men and seven (35.0%) were women. Eleven had iron overload. One had hepatic cirrhosis, two had diabetes mellitus, four had arthropathy, and two had hypogonadotrophic hypogonadism. One proband also had hereditary stomatocytosis, another had beta-thalassemia trait, a third had ethanol intake >60 g daily, and a fourth had porphyria cutanea tarda. No proband had evidence of excess oral or parenteral iron intake, or of viral hepatitis B or C. At diagnosis of hemochromatosis, evaluation for common HFE mutations revealed that eleven probands were C282Y heterozygotes, five were H63D heterozygotes, and four did not inherit C282Y or H63D.
[0046] The mean age of the initial 176 control subjects was 52±15 years (range 18-86 years); 79 (44.9%) were men and 97 (55.1%) were women. There was no significant difference in the mean ages of men and women. Frequencies of HFE genotypes among the control subjects are shown in Table 6. These values are similar to those previously reported from normal persons from the same geographic area.
TABLE 6 Frequencies of HFE Genotypes in Alabama Subjects. Hemochromatosis Probands with “Atypical” HFE Normal Control HFE Genotype Genotypes, % (n) Subjects, % (n) wt/wt 15.00 (3) 60.23 106) C282Y/wt 45.00 (9) 13.06 (23) H63D/wt 20.00 (4) 15.34 (27) S65C/wt 5.00 (1) 1.14 (2) C282Y/S65C 5.00 (1) 0 C282Y/G93R 5.00 (1) 0 H63D/1105T 5.00 (1) 0 H63D/C282Y 0 6.82 (12) H63D/H63D 0 3.41 (6) Results are expressed as percentage (n). The wild-type (wt) allele was defined as the HFE configuration in which the mutations C282Y, H63D, S65C, I105T, or G93R were not detected.
EXAMPLE 4
Identification of Novel HFE Mutations in Hemochromatosis Probands
[0047] The following novel mutations (missense mutations) were identified in probands 1 and 2: exon 2, nt 314T→C (I105T), and exon 2, nt 277G→C (G93R), respectively (Table 7; FIGS. 1 and 2 ). Probands 3 and 4 had a S65C mutation The S65C mutation has been observed in hemochromatosis patients but has not been deemed to be indicative of a disease state. In contrast, the data presented herein indicate that the S65C mutation is diagnostic of a disease state. This result is surprising in view of earlier observations. Other than C282Y or H63D, no HFE exon mutations were detected in the remaining sixteen of the twenty probands (Table 6). Nine probands were heterozygous for a base-pair change at intron 2, nt 4919T/C (SEQ ID NO:27); two probands were homozygous for this base-pair change. Heterozygosity for a base-pair change in intron 4 (nt 6884T→C) was detected only in probands 3 and 4, both of whom also inherited S65C. One proband was heterozygous for a base-pair change at intron 5, nt 7055A→G.
[0048] Using dot blot methodology, heterozygosity for the S65C mutation was detected in two of 176 normal control subjects (Table 6). The G93R or I105T mutations were not detected in normal control subjects (Tables 6 and 8).
EXAMPLE 5
Association of Novel HFE Coding Region Mutations to C282Y and H63D and HFE Intron Alleles
[0049] In proband 1, two mutations of exon 2 (H63D and I105T) were detected. After subcloning the genomic fragment, the subclones revealed that these mutations occurred on separate chromosomes; this observation was confirmed by family studies indicating segregation of I105T
TABLE 7 Phenotypes and Uncommon HFE Genotypes in Alabama Subjects* Age (years), HFE Transferrin Serum Ferritin, Hepatocyte Phlebotomy, Subject† Sex Genotype HLA Type Saturation, % ng/mL Iron Grade Units Proband 1 52 M H63D/I105T A2, 3; B7, 7 62 868 2+ 20 Proband 2† 40 M C282Y/G93R A2, 3; B7, 62 78 861 4+ 34 Proband 3§ 47 F C282Y/S65C A2, 32; B8, 44; 90 281 3+ 37 Bw4, 6; Cw5, 7 Proband 4** 81 F S65C/wt A2, 32; B14, 62 100 5,135 N.D. 37 Normal Control 1 28 M S65C/wt A2, 31; B35, 60 28 141 N.D. N.D. Normal Control 2 69 M S65C/wt A24, 26; B8, 42 747 2+ N.D. B37; Bw4, 6; Cw6, 5 (or 7) *Serum transferrin saturation, serum ferritin concentration, and percutaneous hepatic biopsy were performed before therapeutic phlebotomy was initiated. Reference ranges for these parameters are 15-45%; 20-300 ng/mL (men) and 20-200 ng/mL (women); and 0-1+, respectively. Iron depletion (serum ferritin ≦20 ng/mL) was induced by removing the indicated numbers of units of blood. None of these persons had evidence of hepatic # cirrhosis, diabetes mellitus, hemochromatosis-associated arthropathy, hypogonadotrophic hypogonadism, other endocrinopathy, or cardiomopathy. N.D. = not done. The mutations indicated are exon 4, nt 845G→A (C282Y); exon 2, nt 187C→G (H63D); exon 2, nt 314T→C (I105T); exon 2, nt 277G→C (G93R); and exon 2, nt 193A→T (S65C). The wild-type (wt) allele was defined as an HFE allele in which the mutations C282Y, H63D, S6SC, I105T, or G93R were not detected. †Countries of origin: Probands 1 and 2, England; Proband 3, Wales, England, and Americas (Cherokee); Proband 4, England and Ireland; Normal Control 1, England; Normal Control 2, The Netherlands. ‡The father and sister of Proband 2 are presently undergoing therapy for hemochromatosis and iron overload, but their clinical and genetic data were unavailable. §Proband 3 had porphyria cutanea tarda alleviated with therapeutic phlebotomy. **Proband 4 had hereditary stomatocytosis unaffected by phlebotomy treatments. 37 units of blood were removed by phlebotomy before treatment was discontinued due to stroke apparently unrelated to anemia or iron overload (post-treatment serum ferritin 1,561 ng/mL). Her 59 year-old daughter (who does not have hereditary stomatocytosis) had transferrin saturation 42%, serum ferritin 62 ng/mL, HLA type A1, 32; B14, 15; Bw4, 6; Cw3, 8, and HFE genotype S65C/H63D. # These data permitted assignment of the S65C mutation in this family to a haplotype carrying HLA-A32; linkage of S65C and HLA-A32 was also observed in the family of Proband 3.
[0050] TABLE 8 Frequencies of HFE Alleles in Alabama Subjects. wt* C282Y H63D S65C† I105T G93R Hemochromatosis Probands with 0.500 0.275 0.125 0.050 0.025 0.025 “Atypical” HFE Genotypes (n = 20) Normal Control Subjects (n = 176) 0.750 0.099 0.145 0.006 ‡ ‡ The wild-type (wt) allele was defined as an HFE allele in which the mutations C282Y, H63D, S65C, I105T, or G93R were not detected. †S65C was detected in 2 of 22 (0.091) proband chromosomes and in 2 of 266 (0.0075) control chromosomes that did not bear the C282Y, H63D, S65C, I105T, or G93R mutation. ‡Based on this data set, the frequency of the I105T and G93R HFE alleles is estimated to be <0.0028, respectively.
and H63D ( FIG. 1 ). In proband 2 (HFE genotype C282Y/G93R), RT-PCR analysis (with subsequent subcloning and sequencing) revealed that these HFE mutations occurred on separate chromosomes. Family studies of proband 3 (HFE genotype C282Y/S65C) indicated that the C282Y and S65C HFE alleles segregated independently, establishing their occurrence on separate chromosomes (Table 7, FIG. 3 ).
[0051] In proband 1 (HFE genotype H63D/I105T), the I105T mutation was co-inherited with HLA-A3, B7. In probands 3 and 4 and their respective families, S65C was inherited on the same chromosome as HLA-A32, indicating that HLA-A32 is a marker for chromosomes bearing the S65C mutation, and individuals with HLA-A32 have an increased risk for developing hemochromatosis. The G93R mutation is associated with HLA-A2, and individuals with that haplotype have an increased risk for developing hemochromatosis. The I105T mutation is associated with HLA-A3, e.g., HLA-A3, B7, and individuals with that haplotype have an increased risk for developing hemochromatosis. Among twenty probands tested, the nucleotide polymorphism in intron 4 (nt 6884T→C) was detected in probands 3 and 4, both of whom also had S65C. Subjects that tested positive for the S65C mutation all were found to have the intron 4 (6884T→C) mutation, including two probands (3 and 4), their families, and two normal controls.
EXAMPLE 6
HFE Coding Region Mutations and Clinical Phenotype
[0052] The 110ST and G93R mutations were associated with a hemochromatosis clinical phenotype in probands 1 and 2 who also inherited H63D and C282Y, respectively. Proband 3 had clinical evidence of hemochromatosis, iron overload, and porphyria cutanea tarda associated with compound heterozygosity for C282Y and S65C. Proband 4 had severe iron overload associated with heterozygosity for S65C and co-inheritance of hereditary stomatocytosis (Table 7). The sister of proband 1 (HFE genotype I105T/wt) was not completely evaluated for hyperferritinemia ( FIG. 1 ). Otherwise, family members of probands who were heterozygous for novel HFE mutations described herein had little or no evidence of abnormal iron parameters, a hemochromatosis phenotype, or of iron overload (Table 7 and 9; FIGS. 1 and 3 ). Normal Control 1 who had HFE genotype S65C/wt had a
TABLE 9 Hemochromatiosis (HC) Family study/patent Diagnosis/ intron 4 Tf sat** Ftn** Hepatocyte Subject/Age/Sex HLA Type exon 2 exon 4 5636 bp % ng/ml Iron grade Proband 1/57M (201) A2, 3; B7, 7 H63D/H, 1105T/1 Wt T 62 868 HC/2+ brother/45M(204) H63D/H Wt T* 31 186 sister/50F(203) A3, 3: B7, 7 1105T Wt* T* 37 576 daughter/31F(301) A32, 68 ; B7, 44 1105T/1 Wt* T* 31 56 son/27M(302) A2, 68; B7, 44 H63D/H Wt* T* 33 44 Proband 2/40M A2, 3; B7, 62 G93R/G C282Y/C T 78 861 HC/4+ Father Wt C282Y/Y* T* HC Sister G93R/G C282Y/C* T* HC Proband 3/47(201) A2, 32; B8, 44 S65C/S C282Y/C T/C 90 281 HC/3+ brother/45M(202) A2, 32; B44, 51 S65C/S Wt T/C 33 42 mother/81F(102) A2, 2; B8, 51 Wt C282Y/C T* NT NT sister/33F(204) A2, 7; B27, 51 Wt Wt T* NT NT brother/35M(203) A2, 7; B27, 51 Wt Wt* T* NT NT sister Wt C282Y/C* T* sister S65C/S Wt* T/C* Proband 4/81F A2, 32; B14, 62 S65C/S Wt T/C 100 S135 HC + stomatocytosis daughter/59 • A1, 32; B14, 15 H63D/H, S65C/S Wt* T/C 42 62 Control 1/28M A2, 31; B35, 60 S65C/S Wt T/C 28 141 Control 2/69M A24, 26; B8, 37 S65C/S Wt T/C 42 747 2+ *RE cut **normal (15-45%) ***20-300 ng/ml (men) 2C-200 ng/ml (women)
normal iron phenotype (Table 7). Normal Control 2, who also had the HFE genotype S65C/wt, had hyperferritinemia and mildly increased stainable hepatocellular iron deposition, but had no symptoms or other objective findings attributable to iron overload (Table 7). These data indicate that S65C heterozygosity is associated with abnormal iron parameters.
EXAMPLE 7
HLA Gene Linkage
[0053] In the family of proband 1, the I105T mutation was linked to HLA-A3, B7, markers which are often linked to the C282Y mutation and its ancestral haplotype. HLA-A3, B7 is also significantly more common among C282Y-negative hemochromatosis probands than in normal control subjects tested. S65C was linked to HLA-A32 in probands 3 and 4 (and their respective families). The base-pair change in intron is 4 (nt 6884T→C) was detected only in probands who inherited the S65C mutation. These data indicate that an intron 4 mutation (nt 6884→C) is a marker for chromosomes bearing the S65C HFE allele. Three of four probands who inherited mutated HFE exon 2 mutations described herein also inherited the C282Y or H63D mutations on separate chromosomes. In a fourth proband, the co-inheritance of S65C heterozygosity and hereditary stomatocytosis was associated with severe iron overload.
[0054] Altered interactions of transferrin receptor, transferrin, and C282Y and H63D mutant HFE protein contribute to the pathology of hemochromatosis. The S65C, G93R, and I105T mutations are located within the α1 domain: in the α1 helix of the HFE class I-like heavy chain (I105T and G93R), and at the tip of the A chain loop of the β-pleated sheet (S65C). These mutations affect the overall structure of the HFE gene product, and specifically affect the salt bridge between residues H63 and D95. The I105T substitution also inhibits proper folding of the α1 domain of the HFE gene product, and specifically affects the hydrophobicity of the hydrophobic F pocket.
[0055] Other embodiments are within the following claims. | The invention features a method of diagnosing an iron disorder, e.g., hemochromatosis, or a genetic susceptibility to developing such a disorder in a mammal by determining the presence of a mutation in exon 2 or in an intron of an HFE nucleic acid. | 2 |
BACKGROUND OF THE INVENTION
The present invention relates to a semiconductor memory device and, more particularly, to a MOS (metal oxide semiconductor) type dynamic memory device.
In the MOS type dynamic memory device, as an example of a semiconductor memory device, one transistor/cell type memory device in which a single transistor and a single capacitor are used as a memory cell has dominantly been used aiming at improving a density of integration. In the MOS type dynamic memory device using such memory cells, different signal voltages appearing on a pair of data lines are very small (e.g. about several tens of mV) since the memory cell per se has no amplifying function. To sense such a minute signal, a sense amplifier is used. For accurately sensing the signal voltage by the sense amplifier, prior to the sensing operation by the sense amplifier, the potentials (referred to as initial potentials) on the pair of data lines must be set at the same level.
FIG. 1 shows a circuit construction of a part of a general MOS type dynamic memory device which is related to the present invention.
As shown, a pair of data lines DL and DL are connected to a sense amplifier SA. Coupled with the data lines DL and DL are regeneration circuits RC and RC, a plurality of memory cells (only a couple of memory cells are illustrated, for simplicity), and dummy cells DC and DC. Word lines WL and WL are coupled with the memory cells MC and MC, respectively. The dummy cells DC and DC are also coupled with word lines WLd and WLd, respectively.
The operation of the dynamic memory device as mentioned above will be described referring to FIGS. 2A to 2F. Assume now that a chip enable signal CE (FIG. 2A) is level-shifted from "1" to "0" and the operation phase shifts from an active cycle to a precharge cycle. Through this transient, the word line WL and dummy word line WLd (FIG. 2C) having been activated in the active cycle, the drive pulse φ SA (FIG. 2D) to the sense amplifier SA, and the regeneration pulse φ REF (FIG. 2E) go to "0" level. Then, the precharge pulse φ p (FIG. 2B) goes to "1". When the precharge pulse φ p is at "1" level, the data line DL and DL are precharged through transistors T1, T2 and T3 of the sense amplifier SA, while at the same time the data lines DL and DL are short circuited through the transistors T2 and T3. As a result, the data lines DL and DL are set at the same potential (FIG. 2F). In this case, the data lines DL and DL are generally charged up to the maximum voltage V DD , i.e. the power source voltage, for reducing the stray capacitors associated with the data lines or for ensuring the regeneration of the signal voltages on the data lines which will be performed in the succeeding stage.
To this end, the voltage of the precharge pulse φ p corresponding to "1" level is set at least at V DD +V TH (V TH designates the threshold voltage of each of the transistors T2 and T3). The transistors T7 of the dummy cells DC and DC are also turned on, so that the charge stored in the capacitors Csd of the dummy cells DC and DC are discharged, and the potential stored in the capacitors Csd is a power source voltage V SS ("0" level).
Then, the chip enable pulse CE becomes "1" in level and the operation phase enters the active cycle. In this case, to secure the satisfactory charge into the data lines DL and DL and to ensure the setting of the initial potentials on the data lines to the same value, the precharge pulse φ p is kept at "1" level for a while after the chip enable pulse CE becomes "1" in level and the active cycle starts. The precharge pulse φ p becomes "0", and then one selected word line WL on the data line DL side (the number of word lines WL in a memory of 16 K bits is 128) and the dummy word line WLd on the opposite data line DL side are "1" in level ("1" level on the word lines WL and WL is set at V DD+V TH or more). Subsequently, the charge stored in the capacitors Cs and Csd in the memory cell MC and dummy cell DC which are connected to the selected word lines WL and the dummy word line WLd, respectively, are read out onto the data lines DL and DL, respectively.
At this time, a signal voltage caused by the charge given in accordance with a capacitance ratio of the stray capacitor Cs in the memory cell MC and the stray capacitor C D associated with the data line DL, appears on the data line DL. In this case, the capacitance of the stray capacitor C D is considerably larger than that of the capacitor Cs, C D >>Cs, so that the signal voltage appearing on the data line DL is extremely low. Since the capacitance of the capacitor Csd in the dummy cell DC is approximately 1/2 that of the capacitor Cs in the memory cell MC, there appears on the data line DL a voltage corresponding to an approximately 1/2 that between "1" level and "0" level on the data line DL.
The stored data in the memory cell MC may be detected through the comparison of the magnitudes of those signal voltages on the data lines DL and DL by the cross-connected transistors T4 and T5 in the sense amplifier SA. The sensing operation by the sense amplifier follows. When the drive pulse φ SA (FIG. 2D) for the sense amplifier is "1" in level, the transistor T6 is turned on to in turn operate the transistors T4 and T5. As a result, the potential only on the lower potential data line of the data lines DL and DL drops to "0" in level, and the potential on the higher potential data line is kept as it is so that the signal voltage on the higher potential data line is amplified.
The signal voltage on the higher potential data line is actually very low. For this reason, even if the sense amplifier used is very sensitive, the potential on the higher potential data line drops at the operation time. Then, the potential drop on the data leads line is compensated for by the regeneration circuits RC and RC. The connection points Na and Nb in the regeneration circuits RC and RC are charged when the data lines DL and DL are charged in the precharge cycle.
The regeneration circuit RC (or RC), connected to the data line discharged through the operation of the sense amplifier SA by, for example, DC (or DC), is not operated even when the regeneration pulse φ REF (FIG. 2E) is "1", because the connection point Na (or Nb) is also discharged. In this situation, the higher potential data line, or the data line not discharged, for example, DL (or DL), is still at higher potential even though the potential on that line is dropped. Therefore, the gate source voltage of a barrier transistor T8b (or T8a) in the regeneration circuit RC (or RC) is the threshold voltage or slightly less, so that the barrier transistor T8b (or T8a) is kept off or substantially off. Accordingly, the connection point Nb (or Na) of the regeneration circuit RC (or RC) is charged up to V DD +V TH or more by the capacitor Cb (or Ca) when the regeneration pulse φ REF becomes "1" in level. Accordingly, the higher potential data line is charged up to its maximum voltage V DD through the transistor T9b (or T9a) in the regeneration circuit RC (or RC). In this way, the signal voltage on the higher potential data line is raised to make it easy to sense the data.
The signal voltage difference between the data lines DL and DL when the sense amplifier SA is operated is very small, 20 to 200 mV. Therefore, to correctly sense the data by the sense amplifier, it is necessary to set the potentials (initial potentials) on the data lines DL and DL to substantially the same value before the sensing operation. For example, when a signal voltage difference between the data lines DL and DL is 50 mV, and the setting value difference between the same data lines is 20 mV, the actual signal voltage is reduced almost half.
The initial potential setting is of great significance at the present day, because the signal voltage is reduce a further lower with increase of the memory capacity and with the precharge cycle period (normally 100 μs or so) being shorter with requirement of the high operation speed.
To reliably set the initial potentials on the data lines DL and DL, it might be a satisfactory measure to increase conductances of the transistors T2 and T3 of the sense amplifier SA. This measure, however, is accompanied by increase of the capacitances of the transistors T2 and T3 of the sense amplifier SA against ground. To avoid this, the capacitance of the capacitor for bootstrap in the precharge pulse generation circuit shown in FIG. 3 must be set large. The large capacitor Cp makes it difficult to generate the precharge pulse φ p and increases the necessary chip area when the memory device is integrated in fabrication.
SUMMARY OF THE INVENTION
Accordingly, an object of the present invention is to provide a semiconductor memory device which can reliably set the initial potentials on a pair of data lines, thereby eliminating an increase of chip area and the difficulty of generating the precharge pulse.
According to the present invention, there is provided a semiconductor device comprising: a pair of first and second data lines charged to a predetermined potential during a precharge period; sense amplifier means for sensing a potential of said pair of first and second data lines during an active period provided between the pair of said first and second data lines; and regeneration means provided for said first and second data lines which operate to form at least one of a charge path to said first and second data lines and a short circuit path for short circuiting said first and second data lines during said precharge period and to make the potential of the one of the data lines which is closer to said predetermine potential than that of the other data line, approximate to said predetermined potential.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a circuit diagram of a prior MOS type dynamic memory device;
FIGS. 2A to 2F are waveforms of potential changes at leading portions in the circuit diagram shown in FIG. 1;
FIG. 3 is a circuit diagram of a precharge pulse generation circuit;
FIG. 4 is a circuit arrangement illustrating an embodiment of a semiconductor memory device according to the present invention;
FIGS. 5A to 5F are waveforms of potential changes at the leading portions in the semiconductor device shown in FIG. 4;
FIG. 6 is a circuit diagram illustrating an embodiment of a sense amplifier circuit according to the present invention;
FIG. 7 is a circuit diagram illustrating an embodiment of a regeneration circuit according to the present invention;
FIG. 8 is a circuit diagram illustrating another embodiment of a sense amplifier according to the present invention; and
FIGS. 9 and 10 are circuit diagram illustrating other embodiments of a regeneration circuit according to the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 4 shows an embodiment of a semiconductor memory device according to the present invention. FIGS. 5A to 5F illustrate signal waveforms at the major portions of the semiconductor memory device shown in FIG. 4. In FIG. 4, DL and DL designate a pair of data lines and all transistors used in the embodiment are of N channel and enhancement type. Transistors T21, T22, T23, T24, T25 and T26 make up a sense amplifier. Transistors T27A and T28A, capacitor C A , and transistor T29 make up a regeneration circuit RC on the data line DL side. Transistors T27B and T28B, capacitor C B , and transistor T29 make up a regeneration circuit RC on the data line DL.
A transistor T30 and a capacitor Cs make up a memory cell MC. Transistors T31 and T32, and a capacitor Csd make up a dummy memory cell DC.
The construction of the sense amplifier will be described in detail. The transistors T21 is for applying a high potential power source voltage V DD . The drain of the transistor T21 is connected to the power source V DD and at its source to the drains of the transistors T22 and T23. A precharge pulse φ p (FIG. 5B) is applied to the gate of the transistor T21. The transistors T22 and T23 are for charging and shorting the data lines DL and DL.
The source of the transistor T21 is connected to the data lines DL and DL. Thus, the transistors T22 and T23 form charging paths to the data lines DL and DL and short circuiting paths for short circuiting these data line. The precharge pulse φ p is applied to both the gates of the transistors T22 and T23.
Cross-connected transistors T24 and T25 are used for voltage amplification or data detection. The transistor T24 is connected at the drain to the data line DL and at the gate to the data line DL. The drain of the transistor T25 is connected to the data line DL and at the gate to the data line DL. The sources of the transistors T24 and T25 are connected together with the drain of the transistor T26 for the sense amplifier. The source of the transistor T26 is coupled with the power source voltage V SS ("0" level). The drive pulse φ SA (FIG. 5D) is applied to the gate of the transistor T26.
Although the single sense amplifier is illustrated in the drawing, a plurality of such sense amplifiers, in an actual case, are incorporated in a semiconductor memory device. In this case, the transistors T22 and T23 must be fabricated into the memory device for each sense amplifier SA, while the transistor T21 for applying the high potential voltage V DD and the transistor T26 for discharging to the low potential voltage V SS are not necessarily provided for each sense amplifier, but may be provided commonly for the respective sense amplifiers. When the memory capacity of the semiconductor memory device is 16 K bits, for example, the number of the sense amplifiers is 128. Transistors T21, T26 may be provided commonly for the 128 sense amplifiers.
The construction of the regeneration circuit RC will be described. The transistor T29 is for applying a high voltage power source voltage V DD . The drain of the transistor T29 is connected to the power source voltage V DD and T29's source is connected to the drain of the transistor T27A. The regeneration pulse φ REF II (FIG. 5F) is applied to the gate of the transistor T29. The transistor T28A is connected at the source to the data line DL and at the gate to the power source voltage V DD . A common node N A between the gate of the transistor T27A and the drain of the transistor T28A is connected to one end of the capacitor C A . The other end of the capacitor C A is coupled with a regeneration pulse φ REF I (FIG. 5E).
The drain and the source of the barrier transistor T28A may be replaced with each other according to the voltage. Since, an initial time of the precharge period the common node N A is charged through the data line DL, the data line DL is connected to the drain and the common node N A is connected to the source.
The construction of the regeneration circuit RC will be described. The transistor T29 used for the regeneration circuit RC is also used for the same purpose in the regeneration circuit RC. The transistor T29 is connected at the source to the drain of the transistor T27B of which the source is connected to the data line DL. The transistor T27B is connected at the gate to the drain of the barrier transistor T28B and at the source to the data line DL. A common node between the gate of the transistor T27B and the drain of the transistor T28B is connected at one end of the capacitor C B of which the other end is coupled with the regeneration pulse φ REF I (FIG. 5E). As in the regeneration circuit RC, the drain and source of the barrier transistor T28B may be replaced with each other also in the regeneration circuit RC.
A practical construction of the memory cell MC will be described. The transistor T30 is connected at the drain to the data line DL and at the gate to the corresponding word line WL. The source of the transistor T30 is connected to one end of the capacitor Cs of which the other end is coupled with the power source voltage V DD applied. The memory cells have all the same constructions. In the drawing, the construction of the single memory cell is illustrated and the remaining memory cells are indicated by mere blocks. The same thing is true for the dummy memory cells MC.
A practical arrangement of the dummy cell DC will be described. The transistor T31 is connected at the drain to the data line DL and at the gate to the dummy word line WLd. The source of the transistor T31 is connected to one end of the capacitor Csd of which the other end is connected to the power source voltage V DD ; and also to the drain of the transistor T32. The source of T32 is coupled with the power source voltage V SS . The precharge pulse φ p is applied to the gate of the transistor T32.
Since the construction of the dummy cell DC is also the same as that of the dummy cell DC, it is indicated by a block.
In the figure, C D and C D indicate stray capacitors associated with the data lines DL and DL, respectively. Since a plurality of memory cells MC, MC are connected to the data lines DL, DL and the stray capacitor C D or C D is considerably larger than the capacitor Cs in the memory cell MC or MC, C D >>Cs. The capacitor Csd in the dummy cell DC or DC is approximately 1/2 the capacitor Cs in the memory cell MC or MC.
The operation of the memory device shown in FIG. 4 will be described referring to FIGS. 5A to 5F illustrating timing charts.
When the chip enable pulse CE (FIG. 5A) changes from "1" to "0" and its operation phase shifts to the precharge cycle, the regeneration pulses φ REF I (FIG. 5E) and φ REF II (FIG. 5F) are "0" in level. Then, when the precharge pulse (FIG. 5B) is "1" in level, the data line DL is charged through the transistors T21 and T22 of the sense amplifier SA, and the data line DL is charged through the transistors T21 and T23 of the sense amplifier SA. When the precharge pulse φ p is "1", the data lines DL and DL are short circuited with each other through the transistors T22 and T23. At t1 when both the data lines DL and DL are charged to approximately V DD -V TH (V TH designates the threshold voltage of each transistor T21, T22 and T23), the regeneration pulse φ REF I and φ REF II are both "1".
Also at t1, the common nodes N A and N B in the regeneration circuits RC and RC are both charged up to approximately V DD -V TH . Further, the gate-source voltage of each transistor T28A or T28B is approximately V TH , so that the transistors T28A and T28B are almost in an OFF condition. Accordingly, when the regeneration pulse φ REF I becomes "1" in level at the time point t1, the potentials at the common nodes N A and N B are both bootstrapped to be boosted to a high potential of V DD+V TH or more. As a result, the transistor T27A of the regeneration circuit RC and the transistor T27B of the regeneration circuit RC are turned on, so that the data lines DL and DL are interconnected with each other through the transistors T27A and T27B.
At time t1, the regeneration pulse φ REF II is "1" in level, so that the transistor 29 common for the regeneration circuits RC and RC is turned on. Accordingly, a charge path to the data line DL through the transistors T29 and T27A is formed, and the same time a charge path to the data line DL through the transistors T29 and T27B is formed.
In this way, during the precharge period, the charge and short circuit paths are formed; the charge path formed by the transistors T21, T22 and T23 in the sense amplifier SA, the charge path by the transistors T29, T27A and T27B in the regeneration circuits RC and RC, the short circuit paths by the transistors T22 and T23 in the sense amplifier SA, and the short circuit path by the transistors T27A and T27B in the regeneration circuits RC and RC. Therefore, charging the initial potentials on the data lines DL and DL to the same value is reliably and quickly performed. For example, when the conductances of the transistors T27A and T27B are substantially equal to those of the transistors T22 and T23, a time required for setting the initial value to the same value is reduced by half. This fact greatly contributes to a high accuracy and stable operation of the sense amplifier SA.
Then, the chip enable pulse CE becomes "1" in level and the operation phase of the memory device shifts to the active cycle. As a result, the regeneration pulse φ REF I and φ REF II return to "0" in level in synchronism with the return of the precharge pulse φ p to "0" level. As a result, the setting of the initial potentials on the data lines DL and DL to the same value is finished.
After the precharge pulse φ p is "0", a single word line WL (FIG. 5C) is selected on the data line DL side, for example. And a dummy word line WLd (FIG. 5C) is selected on the data line DL side. As a result, the data, i.e. charge, stored in the capacitor Cs in the memory cell MC connected to the word line WL and the capacitor Csd in the dummy cell DC connected to the dummy word line WLd are respectively read out on the data lines DL and DL, so that signal voltages caused on the read out data, i.e. the charge, appear on the data lines DL and DL.
In this case, since the signal voltages caused in accordance with the capacitance ratio of the capacitors Cs and Csd and the stray capacitors C D and C D appear on the data lines DL and DL, respectively, these signals are very small. Thereafter, the magnitudes of the signal voltages on the data lines DL and DL are compared to each other to detect the stored data. Namely, after the signal voltages appear on the data lines DL and DL, the drive pulse φ SA (FIG. 5D) becomes "1" in level and the discharge transistor T26 is turned on. Then, the transistors T24 and T25 operate, so that only the lower potential data line of those lines DL and DL discharges to "0" in level. The higher potential data line is kept at the higher potential so that the signal voltage on the higher potential data line is amplified and sensed. In this case, when the memory cell MC of the data line DL is selected and the data of the memory cell MC is "0", the low potential data line is the data line DL, while when it is "1", the data line is on the line DL.
After the operation by the sense amplifier SA, the regeneration pulses φ REF I and φ REF II return to "1" level so that the higher potential data line is regenerated. The potential on the higher potential data line, or the data line not discharged, drops to some extent through the sensing operation of sense amplifier SA. Nevertheless, it is still at relatively high potential. For this reason, the gatesource voltage of the barrier transistor T28B (or T28A) in regeneration circuit RC (or RC) is at the threshold voltage or slightly less than that voltage. As a result, the barrier transistor T28B (or T28A) is kept in an OFF state.
Accordingly, the common node N B (or N A ) in the regeneration circuit RC (or RC) is boosted to V DD +V TH or more by the capacitor C B (or C A ) when the regeneration pulse φ REF I is "1" in level. Accordingly, the higher potential data line DL (or DL) is charged up to the maximum potential, or the power source voltage V DD , through the transistor T27B (or T27A) of the regeneration circuit RC (or RC). The memory device shown in FIG. 4 operates as mentioned above.
The "1" level potential of the regeneration pulse φ REF I may be the power source voltage V DD . The "1" level of the regeneration pulse φ REF II must be V DD +V TH or more in order that the data lines DL and DL must be charged up to the power source voltage V DD . The transistor T29 supplied with the regeneration pulse φ REF II necessary for the memory device may be only one. Therefore, such pulse may readily be produced.
Also in the present embodiment, the data lines DL and DL are charged through the regeneration circuits RC and RC and are short circuited to each other. After the data lines DL and DL are charged up to a value near the V DD -V TH through the transistors T21, T22 and T23 of the sense amplifier SA and the regeneration circuits RC and RC are operated, the data lines DL and DL may be charged up to the power source voltage V DD . Therefore, "1" level of the precharge pulse φ p may be the power source voltage V DD . Consequently, the precharge pulse φ p can readily be obtained.
Alternatively, the regeneration pulse φ REF II may be set at "0" level during a period that the precharge pulse φ p is at "1" level, as indicated by a bold dotted line in FIG. 5F so that the charge paths to the data lines DL, DL through the transistors T29, T27A and T27B are not formed, but only the short circuit path through the transistors T27A and T27B is formed.
FIG. 6 shows another embodiment of a semiconductor memory device according to the present invention. In the present embodiment, the transistor T21 for the voltage supply in the sense amplifier SA is omitted. The transistors T22 and T23 are directly connected to the power source voltage V DD , not through the transistor T21. The remaining in the construction is the same as that of the circuit shown in FIG. 4. Accordingly, like numerals are used for designating like portions in FIG. 4.
In the present embodiment, the data lines DL and DL are precharged through the transistors T22 and T23 to boost the common nodes N A and N B in the regeneration circuits RC and RC, which are charged together with the data lines DL and DL. The data line DL is charged through the charge path including the transistors T29 and T27A. The data line DL is charged through the discharge path including the transistors T29 and T27B. Through the short circuit path by the transistors T27A and T27B, the data lines DL and DL are interconnected with each other. Accordingly, no short circuit path by the transistors T22 and T23 is formed, unlike the embodiment shown in FIG. 4.
FIG. 7 shows another embodiment of a semiconductor memory device according to the present invention. In the present embodiment, the transistor T29 shown in FIG. 4 is omitted. The transistors T27A and T27B are directly connected to the power source voltage V DD not through the transistor T29. Accordingly, there is no short circuit path by the transistors T27A and T27B, and the interconnection between the data lines DL and DL is made by only the short circuit path by the transistors T22 and T23. The charge is made through a charge path passing through the transistor T27A, a charge path passing through the transistor T27B, and charge paths passing through the transistors T21 and T22 and the transistors T21 and T23.
It will be understood that the present invention is not limited to the above-mentioned embodiments. For example, as shown in FIG. 8, the transistor T21 is omitted and there may be provided between the data lines DL and DL a short circuiting transistor T41 whose gate receives the precharge pulse φ p .
The regeneration circuit RC may be modified to an arrangement as shown in FIG. 9 in which the transistor T28A shown in FIG. 4 is replaced by a transistor of the depletion type whose gate receives the low potential power source voltage V SS .
As shown in FIG. 10, a proper pulse φ in synchronism with the pulses φ REF I and φ REF II, is applied to the gate at transistor T28A in place of the higher potential power source voltage V DD . With the application of such pulses, the stray capacitance C D when the sense amplifier SA is operated may be reduced.
As seen from the foregoing description, in the present invention, also at the time of setting the initial potentials on the pair of data lines to the same potential, the regeneration circuit is operated to charge and/or short the pair of data lines through the regeneration circuit. With this construction of the semiconductor memory, the initial potentials on the pair of data lines can reliably and quickly be set to the same value, without the difficulty of the generation of the precharge pulse. | A semiconductor device includes: a pair of first and second data lines charged to a predetermined potential during a precharge period; a sense amplifier for sensing the potential of the pair of data lines during an active period; and a regeneration circuit which charges the first and second data lines to the predetermined potential and maintain the potential of the higher potential data line after the sense amplifier senses during the active period. | 6 |
FIELD OF THE INVENTION
[0001] This invention involves a disc type wood chipper and, in particular, a wood chipping machine that is capable of producing wood chips of a small enough size such that the chips can be economically reduced to wood flour utilizing largely energy supplied to the machine for chipping but typically wasted in the chipping and chip discharge process.
BACKGROUND OF THE INVENTION
[0002] This invention relates to a wood chipping machine that utilizes most of the available and unused internal energy of the machine needed to generate chips of a size that they can be further reduced to wood flour in a single low energy cutting and hammering operation. This reduction to wood flour was historically accomplished by chipping logs or wood scraps into chips having a ¾″ length/width or less and then collecting these chips and hammering them into wood flour in a high horsepower, energy inefficient hammer mill. Hammering whole logs and large chips directly into powder has also been attempted but has proven to be extremely inefficient and results in an extremely low production rate.
[0003] Typically disc type chippers having sufficiently large enough production rates suitable for use in economic industrial processes, utilize relatively large diameter discs which are generally in the 72″ (1.8 M) range. Depending on the process involved, between 10 and 40 knives are used to obtain an adequate output rate when the disc is rotated at rim speeds of between 9,200 and 12,000 feet per minute (2800-3600 M/min). Accordingly, these machines require a good deal of energy, a high percentage of which is not consumed or utilized in the chipping process but is discharged from the machine with the chips largely in the form of heat.
SUMMARY OF THE INVENTION
[0004] It is therefore an object of the present invention to more thoroughly utilize virtually all of the energy supplied to a disc type wood chipper to further reduce the wood particle size normally produced in the chipper.
[0005] It is a further object of the present invention to improve large disc type chippers that are used in the production of wood flour.
[0006] It is a further object of the present invention to reduce the costs involved in the production of wood chips of a small size for chemical processing or for the production of pelletized fuels.
[0007] These and other objects of the present invention are attained in a disc type chipping machine having a chipping disc that contains a plurality of generally radially extending slots passing through the disc between its front face to its back face. The disc is enclosed within a protective casing. A primary knife is located within the front face entrance of each slot and is arranged to cut chips of a desired length from a wood work piece that is brought in contact therewith. A counter knife is mounted immediately behind each primary knife and is arranged to slice each chip longitudinally as the chip passes through the slot thus utilizing the energy normally imparted to the chips. A series of hammers are mounted upon the back face of the disc adjacent to each slot which coact with stationary anvils that are mounted upon the inside of the casing to further break up or pulverize the chips leaving each slot. The chips are then delivered by centrifugal force into a flow channel that surrounds the outer back face and rim of the disc. A series of paddle units are mounted upon the disc with each unit having a wing that passes over the rim of the disc to engage the chip in the flow channel and conducts the chips into a discharge duct. In a further refinement, serrated chip cutters are contained on at least one wall of the flow channel which coact with the wings to further reduce the size of the chips prior to their entering the discharge duct. Here again only the energy normally associated with the chipping operation is utilized in this chip reduction operation. The discharge duct is connected to a separator or chip bin in which the chips are separated from air in the flow stream. A roughened or serrated baffle plate is located at the entrance to the separator or bin upon which the entering chips are impinged to again still further reduce the size of the chips utilizing the kinetic energy stored in the chip stream.
BRIEF DESCRIPTION OF THE DRAWING
[0008] For a better understanding of these and other objects of the present invention reference will be made to the following detailed description of the of the invention which is to be read in association with the accompanying drawings, wherein:
[0009] FIG. 1 is a rear perspective view of a wood chipping machine with portions of the machine casing moved back to better illustrate the chipping disc system of the present invention;
[0010] FIG. 2 is a partial perspective view again viewing from the back side of the machine further illustrating the knife alignment contained in the chipper disc slots;
[0011] FIG. 3 is an enlarged perspective view of a counter knife blade that is mounted in each of the disc slots behind the chipper's primary blade;
[0012] FIG. 4 is an enlarged sectional view that is taken along lines 4 - 4 in FIG. 2 ;
[0013] FIG. 5 is a partial enlarged view illustrating the counter knife blade arrangement employed in the main embodiment of the present invention;
[0014] FIG. 6 is a partial enlarged perspective view showing a hammer and anvil mounting arrangement suitable for use in the present chipper;
[0015] FIG. 7 is a partial enlarged perspective view illustrating a series of paddle units employed in the present chipper system;
[0016] FIG. 8 is a perspective view illustrating a top discharge duct of the present machine delivering chips into a chip bin or separator; and
[0017] FIG. 9 is a side elevation showing a chipper having a bottom discharge that employs the chip reducing system of the present invention.
DESCRIPTION OF THE INVENTION
[0018] Turning initially to FIG. 1 there is illustrated a wood chipping machine, generally referenced 10 , that embodies the teachings of the present invention. The machine is enclosed by a heavy metal protective casing generally referenced 12 which encompasses a rotary disc 13 . The disc is mounted upon a horizontally disposed shaft 15 that is supported upon a pair of bearing blocks 16 and 17 . The shaft is turned at a relatively high rim speed of between 9,000 and 13,000 feet per minute (2,800 and 4,000 meters per minute) by a high speed motor and transmission (not shown). In this view, a quarter section 18 of the casing has been detached from the main section of the casing and moved back along a rail system 19 to expose the back side of the disc. Preferably, the disc has a diameter of about 72″ (1.8 meters or more) and contains between 10 and 40 slots 20 - 20 that extend more or less radially from the mid region of the disc toward the outer rim thereof. Slot angles of between 30 and 45 degrees with regard to the front face of the disc can be employed depending upon the energy demands of the system.
[0019] As further illustrated in FIGS. 2-4 , each slot 20 contains a primary blade 23 located in the entrance to the slot at the front face of the disc. The primary blade contains a single knife edge and may have one or more sections that extend across the slot opening. The primary knife is arranged to slice chips of a predetermined length from a log or any other similar wooden work piece that is brought into contact with the front face of the disc through a feed spout or throat (not shown). A second counter knife 25 is mounted in each of the slots immediately behind the primary knife. The surface of the counter knife that contacts the chips is serrated and contains a series of parallel blade elements 27 - 27 that slope upwardly from the back face 28 of the knife toward the front edge face 29 thereof as best shown in FIG. 3 . In assembly, the counter knife blades 27 - 27 are arranged such that they are each aligned perpendicular to the front face 32 and the rear face 33 of the disc. The counter knife blade edges are spaced apart a distance (d) to achieve a product which is substantially smaller than the spacing between the blade edges. The blade edges are positioned to slice each of the chip ribbons coming off the primary blade longitudinally utilizing only the energy normally imparted to the chips but which is not typically used in material size reduction.
[0020] As best shown in FIG. 2 , the two knives are tightly secured in each of the slots by a plurality of bolts 38 - 38 that pass through openings provided in each of the knives and are threaded into the disc.
[0021] This type of knife holder is relatively simple in design, however it provides for ease of positioning of both knifes so that the blades of the counter knife can be properly aligned with the blade of the primary knife while, at the same time enabling the primary blade to be positioned within the slot to produce chips having a desired length that typically is between ¼″ and ⅝″ (6 and 10 mm). As noted above, as the initially cut chips move through each slot they are cut longitudinally by the blades of the counter knife. As illustrated in FIG. 5 , each of the blades on a counter knife may be spaced for example about ⅜ of an inch (10 mm) from its neighbor so that a preponderance of the chips that exit each slot have a width of about ⅜″ (10 mm). As illustrated in FIG. 5 , the counter knife blades are each of equal height between the blade root and its cutting edge. The height of the blades is selected depending upon the width of the slot in which it is mounted so that the maximum number of chips are acted upon as they pass through the slot. In either case, the spacing between the blades cutting edge is uniform as for example the above noted ⅜″ (10 mm).
[0022] Upon leaving each slot, the chips are directed by the centrifugal force generated by the rotating disc toward the rim of the disc and ultimately into a flow channel 40 ( FIG. 1 ) that encompasses the back of the disc. Immediately adjacent to each slot and in general parallel alignment therewith are a plurality of hammer units 52 - 52 that are secured to the rear face of the disc so that the hammer units rotate with the disc. As best seen in FIG. 7 , the hammers are arranged to move through clusters of stationary anvil units 53 - 53 that are mounted upon the inside rear wall 55 of the machine casing within the flow channel. The hammers mounted upon the disc are adapted to pass through spaces provided in the anvil clusters to tear, shard, or otherwise pulverize the chips as they move toward the rim of the disc within the flow channel.
[0023] After the hammering operation is completed, the chips move upwardly in the flow channel into the rim area of the rotating disc. As illustrated in FIG. 8 the top wall 60 of the chute as well as the side wall of the chute are formed by the outer part of the machine casing. A series of paddle assemblies, generally referenced 65 , are bolted to the back face of the disc between some or each of the slots. Each of the paddle assemblies contains an elongated blade 66 that passes over the rim of the disc with the blade substantially filling the top of the chamber 40 so that the blades engage and propel the chips within the chamber into the entrance to discharge chute 67 shown in FIG. 1 .
[0024] A close running clearance can be provided between the edges of the blades and the walls of the chamber. A number of serrated sections 70 - 70 are contained on the inner surface 71 of the top wall of the flow chamber. The serrated sections extend across the entire width of the paddle blades whereby the chips are forced by the rotating disc into contact with the serrations as the paddle blades move thereunder. Here again, due to forces involved and the speed of the disc, the average chip size is further reduced within the chamber before the flow is released to the discharge duct. The upper edge of the paddle blades can also contain serrations 76 to further enhance the effectiveness of the chip reducing process.
[0025] As noted above, the disc rim speed of the machine is preferably between 9,200 and 13,000 feet per minute. Accordingly, the chips entering the duct are moving at or slightly below the rim velocity of the disc. A good deal of kinetic energy is thus contained in the exiting flow stream. As shown in FIG. 9 , the discharge duct in this embodiment is connected to a cyclone separator 80 or any other similar device for separating the chip material from the entering air. The discharge end 77 of the duct is arranged to empty into the separator so that the flow is directed onto the inclined receiving surface 84 of baffle plate 83 . The plate has a roughened or serrated impact surface, against which the still rapidly moving chips are directed causing a still further reduction in the average chip size.
[0026] Turning now to FIG. 10 , there is shown a wood chipper generally referenced 89 that embodies the teachings of the present invention and which is equipped with a chip handling system having a downward discharge configuration. The chipper is mounted upon a substrate such as a cement floor 90 over a chip collecting bin 94 . A downwardly directed discharge duct 91 connects the chip flow channel located at the rear of the disc 13 to the collecting bin. An inclined baffle plate 92 is mounted within the entrance 93 of the bin so that the baffle intercepts the incoming flow stream as it is discharged into the bin. Here again, the impacted surface of the baffle plate is roughened or serrated sufficiently to further pulverize or reduce the size of the incoming chips.
[0027] As should be now evident, the chips produced in the present machine undergo a multi-step reduction in size as they move through the machine. Two of the steps involve the slicing of chips from a wooden work piece while the following steps involve further physically breaking down or pulverizing the chips. These steps are all carried out utilizing the energy already supplied to a chipper for chipping but not normally utilized for significant material size reduction by the machine to produce chips of a size such that the chips can pass freely through a sieve having ⅜″ (10 mm) diameter holes. Accordingly, the chips so produced can be more efficiently and rapidly turned into the extremely small sizes necessary in the production of wood pellets or for use in various chemical or industrial processes.
[0028] While the invention has been described with reference to a preferred embodiment, it will be understood by those skilled in the art that various changes may be made and equivalents may be substituted for elements thereof to adapt to particular situations without departing from the scope of the invention. Therefore, it is intended that the invention not be limited to the particular embodiments disclosed as the best mode contemplated for carrying out this invention, but that the invention will include all embodiments falling within the scope and spirit of the appended claims. | A disc type wood chipper that utilizes a high percentage of the energy required for chipping but not substantially utilized in the material size reduction within the machine to produce chips of a small enough size such that the chips produced can be turned into wood flour or wood pellets with the expenditure of very little additional energy. | 1 |
BACKGROUND OF THE INVENTION
This invention relates to safety devices for straight ladders and extension ladders, more particularly, a ladder safety accessory kit that levels, stabilizes and holds a ladder in place during use, thereby ensuring the safety of a user while climbing and/or performing work while on the ladder.
Many jobs require the use of ladders to reach areas that are not accessible or within reach of a person standing on the ground. Ladders are commonly used to climb onto roofs of houses and other buildings. Ladders are also used to perform jobs, such as painting, washing windows and so forth. Normally, the bottom portion of the ladder rests on the ground or other similar horizontal surface and the upper end of the ladder typically leans against the vertical wall surface of a building or work surface so that the ladder is oriented at an angle which makes it easy and safe for a user to climb up and down. The use of ladders can be very dangerous and is known to be a major cause of accidents. When a ladder is positioned against a structure, it is essential that the ladder be properly angled to prevent the base of the ladder from slipping. However, not every structure is a flat surface and the ground is not always perfectly level. In addition, most bases and or upper portions of most ladders are not adjustable and thus, cannot be adapted for use on a slanted ground or oddly shaped structure. Furthermore, users currently have no way to easily determine if a ladder is horizontally level and placed at a safe angle in relation to a structure. An even further problem with current ladders is the lack of storage space for tools and other items. Although, many ladders do provide trays for placing tools and other items while working on the ladder, these trays are only flat surfaces that do not secure the tools and/or prevent the tools from accidentally falling to the ground.
Therefore, a need exists for a ladder safety accessory kit that provides an upper stabilizer assembly for adjusting the top portion of a ladder to compensate and/or lock onto different shaped structures, a lower stabilizer assembly for adjusting the bottom portion of the ladder to compensate for uneven ground, a leveling measurement device for determining that the ladder is angled correctly and is level and a storage tray for safely storing tools and other items while working on the ladder.
The relevant prior art includes the following references:
Pat. No.
(U.S. unless
stated otherwise)
Inventor
Issue/Publication Date
6,408,984
Cavagnaro
Jun. 25, 2002
5,899,296
Lantz
May 04, 1999
5,850,894
Busenhart
Dec. 22, 1998
5,740,881
Lensak
Apr. 21, 1998
5,476,153
Dickerson et al.
Dec. 19, 1995
5,273,133
Thocher et al.
Dec. 28, 1993
3,805,917
Luther
Apr. 23, 1974
3,708,080
Schlei
Jan. 02, 1973
3,456,757
Sain
Jul. 22, 1969
2,503,626
Mayberry
Apr. 11, 1950
2,196,640
Meier
Apr. 09, 1940
799,782
Ellinger et al.
Sep. 19, 1905
SUMMARY OF THE INVENTION
The primary object of the present invention is to provide a ladder safety accessory kit that is adaptable to any shaped structure or surface.
Another object of the present invention is to provide a ladder safety accessory kit that adjusts to compensate for uneven ground.
An even further object of the present invention is to provide a ladder safety accessory kit allows a user to quickly and easily determine a ladder is angled correctly.
Another object of the present invention is to provide a ladder safety accessory kit that allows a user to quickly and easily determine that a ladder is level.
An even further object of the present invention is to provide a ladder safety accessory kit that provides a storage area for tools and other items.
The present invention fulfills the above and other objects by providing a ladder safety accessory kit having an upper stabilizer assembly, a lower stabilizer assembly, a leveling measurement device and a storage tray. The ladder safety accessory kit may be integrated with new ladders or used to retrofit existing ladders. Typically, a ladder has a front side that a user climbs, a rear side that faces a structure, an upper portion that rests against a structure, a lower portion that rests on the ground, sides, and a plurality of rungs in-between the sides. The upper stabilizer assembly is located on the upper portion of the ladder. The upper stabilizer assembly comprises upper vertical adjustment bars located on both sides of the ladder. Stabilizer bars are slidably attached to the upper vertical adjustment bars, thereby allowing a user to adjust the position of the stabilizer bars on the ladder. The stabilizer bars are also pivotally attached to the vertical adjustment bars, thereby allowing a user to fold the stabilizer bars upward and flat against the vertical adjustment bars for easy storage of the ladder and ladder safety accessory kit Locking means are located on proximal ends of the stabilizer bars. The locking means engage apertures located on the vertical adjustment bars, thereby allowing a user to lock the stabilizer bars at a desired height. The vertical adjustment bars may be permanently attached to a ladder via an attachment means, such as screws, nuts and bolts, welding, rivets, etc., or by other attachment means, such as one or more tubular members. One end of the at least one tubular member is permanently attached to the vertical adjustment bars and the opposite end is placed through a hollow rung of the ladder. The tubular members may be further secured to the ladder via at least one pin, which passes through the rung of the ladder and the tubular member, and/or by a cross member that extends through the length of the rung and engages a tubular member on either side of the ladder.
The lower stabilizer assembly is located on the lower portion of the ladder. Lower vertical adjustment bars are located on both sides of the ladder. Legs are slidably attached to the lower vertical adjustment bars, thereby allowing a user to adjust the length of the legs. Locking means engage apertures located on the lower vertical adjustment bars, thereby allowing a user to lock the legs at a desired height. The lower vertical adjustment bars may be permanently attached to the ladder via an attachment means, such as screws, nuts and bolts, welding, rivets, etc., or by other attachment means, such as one or more tubular members. One end of the at least one tubular member is permanently attached to the lower vertical adjustment bars and the opposite end placed through a hollow rung of the ladder. The tubular members may be further secured to the ladder via at least one pin, which passes through the rung of the ladder and the tubular member, and/or by a cross member that extends through the length of the rung and engages a tubular member on either side of the ladder. Feet are pivotally attached to the legs via pivot points so the ladder can be angled in relation to the feet. The feet may also be folded upward flat against the legs and lower adjustment bars for easy storage of the ladder and ladder safety accessory kit.
A bolt and locking nut assembly secures the feet to the legs and may be used to lock the ladder at a specific angle in relation to the feet, thereby ensuring that the ladder will remain in a locked position when leaned against a structure. A spike is pivotally attached to the foot via a pivot point. The spike may be folded into the foot for storage or when the foot is being used on a hard surface. The spike may also be folded into a downward position so that the spike will dig into the ground, thereby preventing the foot from sliding backwards.
The storage tray is used for holding tools and other materials while performing work on the ladder and is attached to the upper stabilizer assembly between the stabilizer bars. The storage tray may be secured to the stabilizer assembly by an attachment means, such as nuts and bolts, clips, screws, etc. Storage cups in the storage tray may be used for storing items, such as nails, screws, etc. Storage holes in the storage tray may be used for storing tools, such as screwdrivers, paintbrushes, etc. Although the storage tray may be made of any rigid material, it is preferably made of a magnetized metal that will prevent tools and other items from easily falling from the storage tray.
A leveling measurement device is located on either side of the ladder preferably at eye level, thereby allowing a user to read the leveling measurement device while in a standing position. The leveling measurement device has a front cover and a rear cover hingedly attached to the base. A horizontal bubble level is located on an inner surface of the front cover and a vertical horizontal bubble is located on an inner surface of the rear cover. The horizontal bubble level is preferably horizontally positioned on the inner surface of the front cover so a user can determine if the ladder is level and the ladder is not overextended sideways. The vertical bubble level is preferably positioned on the inner surface of the rear cover at angle of approximately 14.5 degrees in relationship to the ground, thereby ensuring that the base of the ladder is positioned at the proper distance from the structure the ladder is leaning against. To use the leveling measurement device, a user first opens the level measurement device so that the front cover and rear cover form a ninety degree angle. Next, the user adjusts the distance between the base of the ladder and the structure so the ladder is being leaned against the structure so that the bubble in the vertical bubble level is located in-between the two indicator lines printed on the vertical bubble level. Finally, the user adjusts the sides of the ladder so that the bubble in the horizontal bubble level is located in-between the two indicator lines printed on the horizontal bubble level.
The above and other objects, features and advantages of the present invention should become even more readily apparent to those skilled in the art upon a reading of the following detailed description in conjunction with the drawings wherein there is shown and described illustrative embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
In the following detailed description, reference will be made to the attached drawings in which:
FIG. 1 is a rear view of a ladder having an upper stabilizer assembly, lower stabilizer assembly and a leveling measurement device of the present invention attached thereto;
FIG. 2 is a side view of a ladder having an upper stabilizer assembly, lower stabilizer assembly and a leveling measurement device of a ladder safety accessory kit attached thereto;
FIG. 3 is a front plan view of two upper vertical adjustment bars secured together by tubular members and cross members;
FIG. 4 is a cross sectional view of an upper vertical adjustment bar;
FIG. 5 is a cross sectional view of an upper vertical adjustment bar having a safety lock attached thereto;
FIG. 6 is a partial cutaway side view of a stabilizer bar and sliding base of an upper stabilizer assembly;
FIG. 7 is a top view of a ladder having an upper stabilizer assembly with a cross bar attached thereto;
FIG. 8 is a top view of a ladder having an upper stabilizer assembly with extension bars forming a V-shaped configuration attached thereto;
FIG. 9 is a top view of a ladder having an upper stabilizer assembly with extension bars forming a V-shaped configuration attached thereto;
FIG. 10 is a top view of a ladder having an stabilizer bar assembly with extension bars attached thereto forming a horizontal extension configuration;
FIG. 11 is a front view of a storage tray of the present invention;
FIG. 12 is a side view of a stabilizer bar having a footer of the present invention attached thereto;
FIG. 13 is a side view of a lower stabilizer assembly of the present invention;
FIG. 14 is a front partial cross sectional view of a leg and foot of the present invention;
FIG. 15 is a front plan view of two lower vertical adjustment bars secured together by cross members;
FIG. 16 is an inside view of a leveling measurement device in a fully open position; and
FIG. 17 is a top view of a leveling measurement device in a partially open position.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
For purposes of describing the preferred embodiment, the terminology used in reference to the numbered accessories in the drawings is as follows:
1 . ladder 2 . upper stabilizer assembly 3 . lower stabilizer assembly 4 . leveling measurement device 5 . ladder safety accessory kit 6 . front surface 7 . rear surface 8 . upper portion 9 . lower portion 10 . side 11 . rung 12 . upper vertical adjustment bar 13 . stabilizer bar 14 . proximal end of stabilizer bar 15 . distal end of stabilizer bar 16 . locking means 17 . aperture 18 . attachment means 19 . tubular member 20 . pin 21 . cross member 22 . lower vertical adjustment bar 23 . leg 24 . vertical slot 25 . cap 26 . base 27 . trigger 28 . lower lever 29 . upper lever 30 . spring 31 . crossbar 32 . cap 33 . extension bar 34 . V-shaped configuration 35 . horizontal extension configuration 36 . storage tray 37 . storage cup 38 . storage hole 39 . tab 40 . footer 41 . flat portion 42 . hook portion 43 . non-skid material 44 . foot 45 . pivot point 46 . bolt 47 . 46 a . locking washer 48 . spike 49 . opening 50 . rear cover 51 . front cover 52 . horizontal bubble level 53 . inner surface of cover 54 . vertical bubble level 55 . inner surface of base 56 . screw 57 . double sided tape 58 . curved slot 59 . flat surface 60 . safety lock 61 . upper plate 62 . lower plate 63 . nut 64 . bolt 65 . lever 66 . eave 67 . house 68 . window 69 . pole 70 . clip
With reference to FIGS. 1 and 2 , rear and side views of a ladder 1 having an upper stabilizer assembly 2 , lower stabilizer assembly 3 and a leveling measurement device 4 of a ladder safety accessory kit 5 attached thereto is shown. The ladder 1 has a front surface 6 that a user climbs, a rear surface 7 that faces a structure, an upper portion 8 that rests against a structure, a lower portion 9 that rests on the ground, sides 10 , and a plurality of rungs 11 in-between the sides 10 . The upper stabilizer assembly 2 is located on the upper portion 8 of the ladder 1 and has upper vertical adjustment bars 12 are located on both sides 10 of the ladder 1 . Stabilizer bars 13 having proximal ends 14 and distal ends 15 are slidably attached to the upper vertical adjustment bars 12 , thereby allowing a user to adjust the position of the stabilizer bars 13 . The stabilizer bars 13 are also pivotally attached to the upper vertical adjustment bars 12 , thereby allowing a user to fold the stabilizer bars 13 upward and flat against the upper vertical adjustment bars 12 , thereby allowing for easy storage of the ladder 1 and ladder safety accessory kit 5 . Locking means 16 , as shown in FIGS. 5 and 6 , are located on proximal ends 14 of the stabilizer bars 13 . The locking means 16 engage apertures 17 located on the upper vertical adjustment bars 12 , thereby allowing a user to lock the each stabilizer bar 13 at a desired height. The upper vertical adjustment bars 12 may be permanently attached to the ladder 1 via an attachment means 18 , such as screws, nuts and bolts, welding, rivets, etc., or by other attachment means 18 , such as at least one tubular member 19 . Tubular members 19 are permanently attached to the upper vertical adjustment bars 12 and the tubular members 19 are placed through rungs 11 of the ladder 1 , thereby securing the upper vertical adjustment bars 12 to the ladder 1 . The at least one tubular member 19 may be further secured to the ladder 1 via at least one pin 20 which passes through the rung 11 the at least one tubular member 19 and/or by a cross member 21 , as shown in FIG. 3 , that extends through the length of the rung 11 and engages the at least one tubular member 19 on both sides 10 of the ladder 1 .
The lower stabilizer assembly 3 is located on the lower portion 9 of the ladder 1 . lower vertical adjustment bars 22 are located on both sides 10 of the ladder 1 . Legs 23 are slidably attached to the lower vertical adjustment bars 22 , thereby allowing a user to adjust the sides 10 of the ladder 1 to accommodate an uneven ground. Feet 44 are pivotally attached to the bottom of the legs 23 , thereby allowing legs 23 to be angled in relation to the feet 44 , as shown further in FIG. 2 . Bolts 46 secure the feet 44 to the legs 23 and are used to lock the legs 23 at desired angles in relation to the feet 44 , thereby ensuring that the ladder 1 will remain in a locked position when leaned against a structure. Locking means 16 , as shown in FIG. 13 , are located in the legs 23 . The locking means 16 engage apertures 17 located on the lower vertical adjustment bars 22 , thereby allowing a user to lock the legs 23 at a desired height. The lower vertical adjustment bars 22 may be permanently attached to the ladder 1 via an attachment means 18 , such as screws, nuts and bolts, welding, rivets, etc., or by other attachment means 18 , such as at least one tubular member 19 . One end of the at least one tubular member 19 is permanently attached to an lower vertical adjustment bar 22 and the opposite end of the tubular member 19 is placed through a rung 11 of the ladder 1 . The at least one tubular member 19 may be further secured to the ladder 1 via at least one pin 20 which passes through the rung 11 the at least one tubular member 19 and/or by a cross member 21 , as shown in FIG. 14 , that extends through the length of the rung 11 and engages the at least one tubular member 19 on both sides 10 of the ladder 1 .
The leveling measurement 4 device, as shown in more detail in FIGS. 15 and 16 , may be located on either side 10 of the ladder 1 preferably at eye level, thereby allowing a user to read the leveling measurement device 4 while in a standing position.
With reference to FIG. 2 , a side view of a ladder 1 having an upper stabilizer assembly 2 , lower stabilizer assembly 3 and a leveling measurement device 4 of a ladder safety accessory kit 5 attached thereto is shown. The ladder 1 has a front surface 6 that a user climbs, a rear surface 7 that faces a structure, an upper portion 8 that rests against a structure, a lower portion 9 that rests on the ground, sides 10 , and a plurality of rungs 11 in-between the sides 10 . The upper stabilizer assembly 2 is located on the upper portion 8 of the ladder 1 . The upper vertical adjustment bars 12 are located on both sides 10 of the ladder 1 . Stabilizer bars 13 having proximal ends 14 and distal ends 15 are slidably attached to the upper vertical adjustment bars 12 , thereby allowing a user to adjust the position of the stabilizer bars 13 in relation to a structure. As shown here, the height of the stabilizer bars 13 are adjusted so that they fit securely underneath the eave 66 of a house 67 , thereby further securing the ladder 1 in place. The stabilizer bars 13 are also pivotally attached to the upper vertical adjustment bars 12 , thereby allowing a user to fold the stabilizer bars 13 upward and flat against the upper vertical adjustment bars 12 , thereby allowing for easy storage of the ladder 1 and ladder safety accessory kit 5 .
The lower stabilizer assembly 3 is located on the lower portion 9 of the ladder 1 . lower vertical adjustment bars 22 are located on both sides 10 of the ladder 1 . Legs 23 are slidably attached to the lower vertical adjustment bars 22 , thereby allowing a user to adjust the sides 10 of the ladder 1 to accommodate an uneven ground. A foot 44 is pivotally attached to the bottom of the leg 23 , thereby allowing leg 23 to be angled in relation to the foot 44 , as shown further in FIG. 2 . A bolt 45 secures the foot 44 to the leg 23 and is used to lock the leg 23 at a desired angle in relation to the foot 44 , thereby ensuring that the ladder 1 will remain in a locked position when leaned against a structure. Locking means 16 , as shown in FIG. 13 , are located in the legs 23 . The locking means 16 engage apertures 17 located on the lower vertical adjustment bars 22 , thereby allowing a user to lock the legs 23 at a desired height. The lower stabilizer assembly 3 allows a user to easily move the ladder 1 across the length of a house 67 without having to readjust the stabilizer bars 13 in relation to the eave 66 of the house 67 . For example, a user may simply lower the height of the ladder 1 using the lower stabilizer assembly 3 , thereby disengaging the stabilizer bars 13 from the eave 66 of the house 67 , and move the ladder 1 over. Then, the user may simply raise the height of the ladder 1 using the lower stabilizer assembly 3 , thereby re-engaging the stabilizer bars 13 to the cave 66 of the house 67
The leveling measurement 4 device, as shown in more detail FIGS. 15 and 16 , may be located on either side 10 of the ladder 1 preferably at eye level, thereby allowing a user to read the leveling measurement device 4 while in a standing position.
With reference to FIG. 3 , a front plan view of two upper vertical adjustment bars 12 secured together by tubular members 19 and cross members 21 is shown. Each upper vertical adjustment bar 12 is substantially tubular shaped with a vertical slot 24 running the length of the upper vertical adjustment bar 12 , as shown further in FIG. 4 . The substantially tubular shape and vertical slot 24 allow for a stabilizer bar 13 to be slidably attached to the upper vertical adjustment bar 12 . A plurality of apertures 17 are located on the upper vertical adjustment bars 12 . The apertures 17 are used in conjunction with a locking means 16 , as shown in FIGS. 5 and 6 , for securing the stabilizer bars 13 at desired heights. The stabilizer bars 13 may be adjusted to different heights to accommodate for securing a ladder to a slanted roof and other surfaces. Caps 25 are located on either end of the upper vertical adjustment bars 12 to prevent the stabilizer bars 13 from sliding too far up or down and becoming disengaged from the upper vertical adjustment bars 12 . Tubular members 19 for attaching the upper vertical adjustment bar 12 to a ladder 1 are attached to the upper vertical adjustment bars 12 . The tubular members 19 are placed through rungs 11 of the ladder 1 . The tubular members 19 may be further secured to the ladder 1 with pins 20 that pass through the rungs 11 and the tubular members 19 . The tubular members 19 may also be further secured to the ladder 1 by cross members 21 that extend through the length of the rungs 11 and engage the tubular members 19 . The cross members 21 are preferably similarly shaped to the tubular members 19 and are only slightly larger diameter wise than the tubular members 19 , thereby allowing for a secure fit between the tubular members 19 and the cross members 21 . Safety locks 60 , as shown further in FIG. 5 , are located above and below the stabilizer bars 13 .
With reference to FIG. 4 , a cross sectional view of an upper vertical adjustment bar 12 is shown. The upper vertical adjustment bar 12 is substantially tubular shaped with a vertical slot 24 running the length of the upper vertical adjustment bar 12 . The substantially tubular shape and vertical slot 24 allow for a stabilizer bar 13 to be slidably attached to the upper vertical adjustment bar 12 , as shown previously in FIG. 3 .
With reference to FIG. 5 , a cross sectional view of an upper vertical adjustment bar 12 having a safety lock 60 attached thereto is shown. The safety lock 60 has an upper plate 61 and a lower plate 62 secured together by a nut 63 and bolt 64 . The safety lock 60 is placed in a vertical slot 24 of an upper vertical adjustment bar 12 . A lever 65 secured to one end of the bolt 64 pulls the upper plate 61 and lower plate 62 together when in a locked position, thereby sandwiching the the edges of the vertical slot 24 and locking the safety lock 60 in place on the vertical adjustment bar 12 . A spring 30 located between the upper plate 61 and lower plate 62 keep the upper plate 61 and a lower plate 62 separated when the lever 65 is in an unlocked position.
With reference to FIG. 6 , a side view of a stabilizer bar 13 and sliding base 26 of an upper stabilizer assembly 2 is shown. The stabilizer bar 13 has a proximal end 14 and a distal end 15 . The stabilizer bar 13 is pivotally attached at the proximal end 14 to the base 26 , thereby allowing the stabilizer bar 13 to be folded upward. The base 26 fits inside an upper vertical adjustment bar 12 , as shown previously in FIG. 3 . When the base 26 is placed inside the upper vertical adjustment bar 12 , the stabilizer bar 13 extends through a vertical slot 24 located in the upper vertical adjustment bar 12 , as shown previously in FIG. 3 . Apertures 17 located on the stabilizer bar 13 allow a user to attach various accessories to the stabilizer bar. A locking means 16 having a trigger 27 located in the proximal end 14 of the stabilizer bar and the base 26 is accessible through an opening 49 on the stabilizer bar 13 .
With reference to FIG. 7 , a partial cutaway side view of a stabilizer bar 13 and sliding base 26 of an upper stabilizer assembly 2 is shown. The stabilizer bar 13 has a proximal end 14 and a distal end 15 . The stabilizer bar 13 is pivotally attached at the proximal end 14 to the base 26 , thereby allowing the stabilizer bar 13 to be folded upward. The base 26 fits inside an upper vertical adjustment bar 12 , as shown previously in FIG. 3 . When the base 26 is placed inside the upper vertical adjustment bar 12 , the stabilizer bar 13 extends through a vertical slot 24 located in the upper vertical adjustment bar 12 , as shown previously in FIG. 3 . Apertures 17 located on the stabilizer bar 13 allow a user to attach various accessories to the stabilizer bar. A locking means 16 having a trigger 27 located in the proximal end 14 of the stabilizer bar and the base 26 is accessible through an opening 49 on the stabilizer bar 13 . The locking means 16 has a lower lever 28 and an upper lever 29 both pivotally attached to the sliding base 26 . Springs 30 keep the upper lever 29 and lower lever 28 in a locked position so that the upper lever 29 and lower lever 28 are both engaged in the at least one aperture 17 of the upper vertical adjustment bar 12 . By pushing upward on the trigger 27 , pressure is applied to the springs 30 and the upper lever 29 is moved in an angled upward direction away from and out of the at least one aperture 17 and the lower lever 28 is moved in a angled downward direction away from and out of the at least one aperture 17 .
With reference to FIG. 8 , a top view of a ladder 1 having an upper stabilizer assembly 2 with a cross bar 31 attached thereto is shown. Upper vertical adjustment bars 12 are located on both sides 10 of the ladder 1 . Proximal ends 14 of stabilizer bars 13 are slidably attached to the upper vertical adjustment bars 12 , thereby allowing a user to adjust the position of the stabilizer bars 13 . The cross bar 31 is attached to distal ends 15 of the stabilizer bars 13 . The cross bar 31 allows a user to safely lean the ladder 1 against a house 67 without having to lean the ladder 1 directly on a window 68 . Caps 32 made of non-skid material are located on both ends of the cross bar 31 .
With reference to FIG. 9 , a top view of a ladder 1 having an upper stabilizer assembly 2 with extension bars 33 forming a V-shaped configuration 34 attached thereto is shown. Upper vertical adjustment bars 12 are located on both sides 10 of the ladder 1 . Proximal ends 14 of stabilizer bars 13 are slidably attached to the upper vertical adjustment bars 12 , thereby allowing a user to adjust the position of the stabilizer bars 13 . The extension bars 33 are pivotally attached to distal ends 15 of the stabilizer bars 13 , thereby allowing the extension bars 33 to be configured in different shapes depending on what type of structure the ladder 1 is being placed against. Here, the extension bars 33 are folded inward, thereby creating a V-shape configuration 34 . The V-shape configuration 34 allows a user to safely lean the ladder 1 against structures, such as poles 69 and corners. A cross bar 31 attached to both stabilizer bars 13 and extension bars 33 adds extra strength to the upper stabilizer bar assembly 2 when it is placed against a structure.
With reference to FIG. 10 , a top view of a ladder 1 having a stabilizer bar assembly 2 with extension bars 33 attached thereto forming a horizontal extension configuration 35 is shown. Upper vertical adjustment bars 12 are located on both sides 10 of the ladder 1 . Proximal ends 14 of stabilizer bars 13 are slidably attached to the upper vertical adjustment bars 12 , thereby allowing a user to adjust the position of the stabilizer bars 13 . The extension bars 33 are pivotally attached to distal ends 15 of the stabilizer bars 13 , thereby allowing the extension bars 33 to be configured in different shapes depending on what type of structure the ladder 1 is being placed against. Here, the extension bars 33 are folded outward, thereby creating ninety degree angles with the stabilizer bars 13 . This horizontal extension configuration 35 allows a user to safely lean the ladder 1 against a house 67 without having to lean the ladder 1 directly on a window 68 . Cross bars 31 attached to both the stabilizing bars 13 and the extension bars 33 add extra strength to the upper stabilizer bar assembly 2 when it is placed against a structure. A storage tray 36 having a flat surface 59 for holding tools and other materials while performing work on the ladder 1 is attached to the upper stabilizer assembly 2 between the stabilizer bars 13 . Storage cups 37 located in the in the storage tray 36 may be used for storing items, such as nails, screws and so forth. Storage holes 38 located in the in the storage tray 36 may be used for storing tools, such as screwdrivers, paintbrushes and so forth. Although the storage tray 36 may be made of any rigid material, it is preferably mad of a magnetized metal that will prevent tools and other items from easily falling from the storage tray 36 .
With reference to FIG. 11 , a front view of a storage tray 36 of the present invention is shown. The storage tray 36 is used for holding tools and other materials while performing work on a ladder 1 and may be attached to an upper stabilizer assembly 2 between the stabilizer bars 13 , as previously shown in FIG. 9 , or directly to a ladder using attachment means 18 , such as screws, nuts and bolts, welding, rivets, clips, etc. As shown here, the storage tray has a plurality of tabs 39 extending downward for the storage tray 36 . The tabs 39 have apertures 17 for receiving attachment means 18 , such as bolts, screws, etc., for attaching the storage tray 36 to the upper stabilizer assembly 2 . The storage tray 36 has a flat surface 60 with storage cups 37 located in the in the storage tray 36 may be used for storing items, such as nails, screws and so forth. Storage holes 38 , as shown previously in FIG. 10 , located in the in the storage tray 36 may be used for storing tools, such as screwdrivers, paintbrushes and so forth.
With reference to FIG. 12 , a side view of a stabilizer bar 13 having a footer 40 of the present invention attached thereto is shown. The footer 40 has a flat portion 41 and a hook portion 42 and is slidably attached to the stabilizer bar 13 having at least one aperture 17 . A locking means 16 , such as a bolt, cotter pin etc., engages the at least one aperture, thereby locking the footer 40 in a desired position. The flat portion 41 may have an outer layer non-skid material 43 , such as rubber, to prevent slipping. The footer 40 may be placed on the stabilizer bar 13 with the flat portion 41 facing toward a ladder 1 or the hook portion 42 facing toward a ladder 1 . For example, the footer 40 may be placed on the stabilizer bar 13 with the hooked portion 42 facing the ladder 1 , thereby allowing a user to hook the footer 40 over power lines or other elevated cables to prevent the ladder 1 from tilting backwards while in use. Alternatively, the footer 40 may be placed on the stabilizer bar 13 with the flat portion 41 facing the ladder 2 , thereby allowing a user to lock the ladder 2 against the top of a wall.
With reference to FIG. 13 , a side view of a lower stabilizer assembly 3 of the present invention is shown. A lower vertical adjustment bar 22 is substantially tubular shaped with a vertical slot 24 running the length of the lower vertical adjustment bar 22 . The substantially tubular shape and vertical slot 24 allow a leg 23 to be slidably attached to the lower vertical adjustment bar 22 . A plurality of apertures 17 are located on the lower vertical adjustment bar 22 . The apertures 17 are used in conjunction with a locking means 16 to adjust and secure the leg 23 to a desired height. A cap 25 located on the top of the lower vertical adjustment bar 22 prevents the leg 23 from sliding too far up the lower vertical adjustment bar 22 . A foot 44 is pivotally attached to the bottom of the leg 23 via a pivot point 45 , thereby allowing leg 23 to be angled in relation to the foot 44 . A bolt 46 secures the foot 44 to the leg 23 through a curved slot 58 that allows a user to lock the leg 23 at a desired angle in relation to the foot 44 , thereby ensuring that a ladder 1 will remain in a locked position when leaned against a structure, as shown previously in FIG. 2 . A spike 48 is pivotally attached to the foot 44 . The spike 48 may be folded into the foot 44 for storage or when the foot 44 is being used on a hard surface. The spike 48 may be folded down, as shown here, when the foot is being used on soft ground so that the spike 48 will dig into the ground, thereby preventing the foot 44 from sliding backwards.
With reference to FIG. 14 , a front partial cross sectional view of a leg 23 and foot 44 of the present invention is shown. The foot 44 is pivotally attached to the bottom of the leg 23 via a pivot point 45 , thereby allowing leg 23 to be angled in relation to the foot 44 . A bolt 46 and locking washer 46 a secure the foot 44 to the leg 23 and are used to lock the leg 23 at a desired angle in relation to the foot 44 , thereby ensuring that a ladder 1 will remain in a locked position when leaned against a structure, as shown previously in FIG. 2 . A locking means 16 having a trigger 27 located in the leg 23 extends out of an opening 49 of the leg 23 . The locking means 16 has a lower lever 28 and an upper lever 29 both pivotally attached to the leg 23 . Springs 30 keep the upper lever 28 and lower lever 29 in a locked position so that the upper lever 28 and lower lever 29 are both engaged in an at the at least one aperture 17 of the lower vertical adjustment bar 12 .
With reference to FIG. 15 , a front plan view of two lower vertical adjustment bars 22 secured together by cross members 21 is shown. Tubular members 19 for attaching the upper vertical adjustment bar 12 to a ladder 1 are attached to the lower vertical adjustment bars 22 . The tubular members 19 are placed through rungs 11 of the ladder 1 . The tubular members 19 may be further secured to the ladder 1 with pins 20 that pass through the rungs 11 the tubular members 19 and/or by cross members 21 that extend through the length of the rungs 11 and engage the tubular members 19 . The cross members 21 are preferably similarly shaped to the tubular members 19 and are only slightly larger diameter wise than the tubular members 19 , thereby allowing for a secure fit between the tubular members 19 and the cross members 21 .
With reference to FIG. 16 , an inside view of a leveling measurement device 4 in a fully open position is shown. The leveling measurement device 4 has a rear cover 50 and a front cover 51 hingedly attached to each other. A horizontal bubble level 52 is located on an inner surface 53 of the front cover 51 and a vertical bubble level 54 located on an inner surface 55 of the rear cover 50 . The horizontal bubble level 52 is preferably horizontally positioned on the inner surface 53 of the front cover 51 so a user can determine if a ladder 1 is level and the ladder 1 is not leaning sideways. The vertical bubble level 54 is preferably positioned on the inner surface 55 of the rear cover 50 at an angle of approximately 14.5 degrees in relationship to the ground so a user can determine if a lower portion 9 of a ladder 1 is positioned at the proper distance from the structure the ladder 1 is leaning against. The leveling measurement device 4 may be attached to a ladder 1 , as shown in FIG. 1 , via an attachment means 18 , such as screws 56 , double sided tape, a hook and loop fastener, etc. The leveling measurement device 4 is preferably attached to a ladder 1 so that the leveling measurement device 4 is at eye level. Clips 70 for securing the vertical bubble level 54 to the inner surface 55 of the rear cover 50 are provided. The clips 70 allow a user position the vertical bubble level 54 at the proper angle depending on which side of a ladder 1 the leveling measurement device 4 is being attached to. To use the leveling measurement device 4 , a user first opens the level measurement device 4 so that the front cover 51 and rear cover 50 form a ninety degree angle. Then the user adjusts the sides 10 of the ladder 1 so that the bubble in the horizontal bubble level 52 is located in-between the two indicator lines printed on the horizontal bubble level. Next, the user adjusts the distance between the lower portion 9 of the ladder 1 and the structure the ladder 1 is being leaned against so that the bubble in the vertical bubble level 54 is located in-between the two indicator lines printed on the vertical bubble level 54 . The vertical bubble levels 52 , 54 may be filled with a liquid that glows in the dark, thereby allowing a user to see the bubble levels 52 , 54 to be seen in the dark.
Finally with reference to FIG. 17 , a top view of a leveling measurement device 4 in a partially open position is shown. The leveling measurement device 4 has a rear cover 50 and a front cover 51 hingedly attached to each other. A horizontal bubble level 52 is located on an inner surface 53 of the front cover 51 and a vertical bubble level 54 located on an inner surface 55 of the rear cover 50 . The horizontal bubble level 52 is preferably horizontally positioned on the inner surface 53 of the front cover 51 so a user can determine if a ladder 1 is level and the ladder 1 is not leaning sideways. The vertical bubble level 54 is preferably positioned on the inner surface 55 of the rear cover 50 at an angle of approximately 14.5 degrees in relationship to the ground so a user can determine if a lower portion 9 of a ladder 1 is positioned at the proper distance from the structure the ladder 1 is leaning against. The leveling measurement device 4 may be attached to a ladder 1 , as shown in FIG. 1 , via an attachment means 18 , such as screws, double sided tape 57 , a hook and loop fastener, etc.
It is to be understood that while a preferred embodiment of the invention is illustrated, it is not to be limited to the specific form or arrangement of parts herein described and shown. It will be apparent to those skilled in the art that various changes may be made without departing from the scope of the invention and the invention is not to be considered limited to what is shown and described in the specification and drawings. | A ladder safety accessory kit ( 5 ) for straight and extension ladders ( 1 ) having an upper stabilizer assembly ( 2 ) that makes the ladder adaptable to any shaped structure or surface, a lower stabilizer assembly ( 3 ) that makes the ladder adjustable to accommodate for uneven ground, a leveling measurement device ( 4 ) that allows a user to quickly and easily determine that the ladder is level and angled correctly and a storage tray ( 36 ) that provides a storage area for tools and other items. The ladder safety accessory kit may be integrated with new ladders or used to retrofit existing ladders. | 4 |
CROSS-REFERENCE TO RELATED APPLICATIONS
The present application is a continuation application, which claims priority to the co-pending United States application for patent, having the Ser. No. 13/506,655, filed May 7, 2012, which in turn claims priority to the United States application having the Ser. No. 12/653,152, filed Dec. 9, 2009, now U.S. Pat. No. 8,196,515. Each of the above-referenced applications is incorporated by reference herein in its entirety.
FIELD
Embodiments usable within the scope of the present disclosure relate, generally, to power sources and methods usable to actuate a subsurface tool, and more specifically, to a thermite-based power source usable to generate pressure in a subsurface environment suitable for moving and/or actuating subsurface tools.
BACKGROUND
Subsurface tools, placed downhole within a well, are used for a variety of purposes. Such tools can include packers or plugs, cutters, other similar downhole tools, and setting tools used in conjunction with such devices.
For example, in a typical downhole operation, a packer can be lowered into a well and positioned at a desired depth, and a setting tool can be positioned above the packer in operative association therewith. An explosive power charge is then provided in conjunction with the setting tool. When it is desired to set the packer, the power charge is initiated, which causes gas to be rapidly produced, forcefully driving a movable portion of the setting tool into a position to actuate the packer to seal a desired area of the well. The gas can also provide sufficient force to shear a shear pin or similar frangible member to separate the setting tool from the packer.
The force applied to a subsurface tool by a power charge and/or a setting tool must be carefully controlled. The force must be sufficient to set a packer or to similarly actuate other types of downhole tools; however, excessive force can damage portions of a downhole tool, rendering it ineffective. Additionally, a power charge must be configured to provide force for a sufficient period of time. An explosive force provided for an extremely short duration can fail to actuate a tool, and in many cases a “slow set” is preferred due to favorable characteristics provided when actuating a tool in such a manner. For example, when setting a packer, a “slow set” provides the packer with improved holding capacity.
Conventional power charges are classified as explosive devices. Most power charges include black powder and/or ammonium perchlorate, and are configured to provide a short, forceful pressure to a subsurface tool to actuate the tool. An explosive force can often create shockwaves within a well bore, which can undesirably move and/or damage various tools and other components disposed within.
Classification of power charges as explosive devices creates numerous difficulties relating to their transport and use. Shipment of explosive devices on commercial carriers, such as passenger and cargo airplanes, is prohibited. Further, shipment of explosive devices via most trucking companies or similar ground transport is also prohibited. Permissible truck, rail, and ship-based modes of transport are burdened by exacting and costly requirements. Shipments of explosives by rail require buffering areas around an explosive device, resulting in inefficient spacing of cargo with increased cost to the shipper. Shipments by truck require use of vehicles specifically equipped and designated to carry explosive devices, which is a costly process due to the hazards involved. Shipment using ships is subject to regulation by port authorities of various nations, grounded in national security concerns, which greatly increases the time and expense required for the shipment.
The difficulties inherent in the shipment of explosive devices are complicated by the fact that numerous oil and gas wells requiring use of power charges are located in remote locales, which are subject to various national and local regulations regarding explosive devices, and which often require numerous modes of transportation and numerous carriers to reach.
Operation of explosive power charges is also restricted, depending on the location in which an operation is to be performed. In many locations, the user of a power charge must be specifically licensed to handle and operate explosive devices. Some nations do not allow transport or use of explosive devices within their borders without obtaining a special permit to requisition a desired explosive device from a designated storage area. In others, various governmental agents or other specialists must be present to ensure safe operation of the device.
In addition to the regulatory difficulties present when using an explosive power charge, the explosive nature of conventional power charges can inhibit the effectiveness of such devices.
In some instances, a packer or similar subsurface tool can become misaligned within a wellbore. Use of an explosive power charge to provide a short, powerful burst of pressure to actuate the tool can cause the tool to set, or otherwise become actuated, in a misaligned orientation, hindering its effectiveness. While conventional power charges are configured to provide a sustained pressure over a short period of time, this period of time is often insufficient to allow a misaligned tool to become realigned within a wellbore, while a longer, slower application of pressure (a “slow set”) can cause a tool to become aligned as it is actuated. Additionally, a longer, slower application of pressure to a subsurface tool can improve the quality of the actuation of the tool (e.g., improved holding capacity of a packer), as described previously.
A further complication encountered when using explosive power charges relates to the heat transfer created by the device. Conventional power charges can heat a subsurface tool to temperatures in excess of 2,000 degrees Fahrenheit. These extreme temperatures can cause excessive wear to tool components, leading to the degradation of one or more portions of the tool.
A need exists for a power source, usable as an alternative to conventional power charges, which does not contain explosive substances, thereby avoiding the difficulties inherent in the transport and use of explosive devices.
A further need exists for a power source that provides a continuous pressure to a subsurface tool over an extended period of time, enabling alignment of misaligned tools and improving the quality of the actuation of the subsurface tool, while providing an aggregate pressure equal to or exceeding that provided by conventional power charges.
A need also exists for a power source that provides pressure sufficient to actuate a subsurface tool without increasing the temperature of the tool to an extent that can cause significant damage or degradation.
Embodiments usable within the scope of the present disclosure meet these needs.
SUMMARY
Embodiments usable within the scope of the present disclosure relate, generally, to a power source, which can be usable to actuate a variety of subsurface tools, such as packers, plugs, cutters, and/or a setting tool operably associated therewith. The power source can incorporate use of non-explosive, reactive components that can provide a pressure sufficient to actuate a subsurface tool. The aggregate pressure provided during the reaction of the components can equal or exceed that provided by a conventional explosive power charge. By omitting use of explosive components, the power source is not subject to the burdensome restrictions relating to use and transport of explosive devices, while providing a more continuous pressure over a greater period of time than a conventional explosive power charge.
In an embodiment, the power source includes thermite, present in a quantity sufficient to generate a thermite reaction. Thermite is a mixture that includes a powdered or finely divided metal, such as aluminum, magnesium, chromium, nickel, and/or similar metals, combined with a metal oxide, such as cupric oxide, iron oxide, and/or similar metal oxides. The ignition point of thermite can vary, depending on the specific composition of the thermite mixture. For example, the ignition point of a mixture of aluminum and cupric oxide is about 1200 degrees Fahrenheit. Other thermite mixtures can have an ignition point as low as 900 degrees Fahrenheit.
When ignited, the thermite can produce a non-explosive, exothermic reaction. The rate of the thermite reaction occurs on the order of milliseconds, while an explosive reaction has a rate occurring on the order of nanoseconds. While explosive reactions can create detrimental explosive shockwaves within a wellbore, use of a thermite-based power charge can avoid such shockwaves.
The power source can include a gas producing substance and/or compound disposed in association with the thermite. Pressure from the gas produced can be usable to actuate a subsurface tool, such as by causing movement of a movable portion of a tool from a first position to a second position. In an embodiment, the substance and/or compound includes a polymer that can produce a gas responsive to the thermite reaction, and as such, the present application may refer to use of a “polymer” in many instances; however, it should be understood that the term “polymer” is used synonymously with any substance that can produce gas responsive to a thermite reaction.
Usable polymers can include, without limitation, polyethylene, polypropylene, polystyrene, polyester, polyurethane, acetal, nylon, polycarbonate, vinyl, acrylin, acrylonitrile butadiene styrene, polyimide, cyclic olefin copolymer, polyphenylene sulfide, polyketone, polyetheretherketone, polyetherimide, polyethersulfone, polyamide imide, styrene acrylonitrile, cellulose propionate, diallyl phthalate, melamine formaldehyde, other similar polymers, or combinations thereof.
In an embodiment, the polymer can take the shape of a container, disposed exterior to, and at least partially enclosing, the thermite. Other associations between a polymer and thermite can be usable, such as substantially mixing the polymer with the thermite, or otherwise combining the polymer and thermite, such that the polymer produces gas responsive to the thermite reaction. For example, a usable polymer can be included within a thermite mixture as a binding agent. In an embodiment, a polymer can be present in an amount ranging from 110% the quantity of thermite to 250% the quantity of thermite, and in a preferred embodiment, in an amount approximately equal to 125% the quantity of thermite.
Use of a power source that includes thermite and a polymer that produces gas when the thermite reaction occurs provides increased pressure when compared to reacting thermite without a polymer. Use of thermite alone may fail to produce sufficient pressure to actuate a subsurface tool in some cases.
In an embodiment, the gas produced by the polymer can slow the thermite reaction, while being non-extinguishing of the thermite reaction, which enables the power source to provide a continuous pressure over a period of time. In an embodiment, the thermite reaction, as affected by the gas, can occur over a period of time in excess of one minute. The aggregate pressure produced by the power source over the time, within which the thermite reaction occurs, can exceed the pressure provided by a conventional explosive power charge. Additionally, use of a continuous pressure, suitable for a “slow set,” can improve the quality of the actuation of certain subsurface tools, such as packers. Further, when a packer or a similar tool has become misaligned in a borehole, application of a continuous, steadily increasing pressure over a period of time can cause the misaligned tool to straighten as it is actuated. Use of an explosive burst of force provided by a conventional power charge can instead cause a misaligned tool to become actuated in an improper orientation.
In embodiments where a “slow set” may not be desired, such as when actuating a subsurface tool requiring pressure to be exerted for a period of time less than that of the thermite reaction, one or more accelerants can be included within the power source. For example, inclusion of magnesium or a similar accelerant, in association with the thermite and/or the polymer can cause a reaction that would have occurred over a period of two to three minutes to occur within ten to twenty seconds.
In a further embodiment, the polymer and/or the gas can reduce the heat transfer from the thermite reaction to the subsurface tool, or to another adjacent object. While typically, an exothermic thermite reaction can increase the temperature of an adjacent object by up to 6,000 degrees Fahrenheit, potentially causing wear and/or degradation of a subsurface tool, an embodiment can include a quantity and configuration of thermite and polymer that can control the heat transfer of the reaction, such that the temperature of an adjacent subsurface tool can be increased by only 1000 degrees Fahrenheit or less. During typical use, embodiments of the present power source could increase the temperature of an adjacent tool by only 225 degrees Fahrenheit or less.
In one possible method of use, a power source, as described above, can be provided in operative association with a movable member of a subsurface tool. For example, a packer secured to a setting tool, having a piston or mandrel used to actuate the packer, can be lowered into a wellbore, the power source being placed adjacent to, or otherwise in operative association with, the piston or mandrel. A thermal generator, torch, or similar device, usable to begin the thermite reaction, can be provided in association with the thermite.
When the tool has been lowered to a selected depth and it is desirable to actuate the tool, the thermal generator can be used to initiate the thermite reaction, such as by providing current to the thermal generator through electrical contacts with a source of power located at the well surface. The power source can be actuated using a self-contained thermal generator that includes batteries, a mechanical spring, and/or another source of power usable to cause the thermal generator to initiate the thermite reaction. Initiation of the reaction can be manual (e.g., through remote or direct actuation), or the reaction can be initiated automatically, responsive to a number of conditions including time, pressure, temperature, motion, and/or other factors or conditions, through use of various timers and/or sensors in communication with the thermal generator.
As the thermite reacts, the polymer produces gas, and the gas from the polymer and/or the thermite reaction can apply a pressure to the movable member sufficient to actuate the subsurface tool. The gas from the polymer can slow the thermite reaction, thereby enabling, in various embodiments, provision of a continuous pressure to the movable member over a period of time, and/or prevention of excessive heat transfer from the thermite reaction to the subsurface tool. As described above, the thermite reaction can provide a continuous, increasing pressure such that if a packer or similar tool has become misaligned, pressure from the power source will push the tool into alignment prior to actuating the tool.
The force provided by the power source can be controlled by varying the quantity of thermite and/or the quantity of polymer. In an embodiment, the force provided by the power source can be used to perform actions subsequent to actuating the subsurface tool. For example, after actuating a setting tool to cause setting of a packer, the force from the power source could shear a shear pin or similar item to cause separation of the setting tool from the packer.
Embodiments usable within the scope of the present disclosure thereby provide a non-explosive alternative to conventional explosive power charges, that can provide a continuous pressure over a period of time that equals or exceeds the aggregate pressure provided by conventional alternatives, and can reduce heat transfer from the power source to a subsurface tool.
BRIEF DESCRIPTION OF THE DRAWINGS
In the detailed description of various embodiments of the present invention presented below, reference is made to the accompanying drawings, in which:
FIG. 1 depicts an embodiment of a subsurface tool within a wellbore, in operative association with an embodiment of a power source usable within the scope of the present disclosure.
FIG. 2 depicts a cross-sectional view of an embodiment of a power source usable within the scope of the present disclosure.
Embodiments usable within the scope of the present disclosure are described below with reference to the listed Figures.
DETAILED DESCRIPTION OF THE EMBODIMENTS
Before explaining selected embodiments in detail, it is to be understood that the present invention is not limited to the particular embodiments described herein and that the present invention can be practiced or carried out in various ways.
Referring now to FIG. 1 , an embodiment of a power source usable within the scope of the present disclosure is shown within a wellbore, in operative association with a subsurface tool.
Specifically, FIG. 1 depicts a wellbore ( 13 ), drilled within the earth ( 14 ), extending from the surface ( 16 ) to a desired depth. The wellbore has a packer ( 11 ) disposed therein. While FIG. 1 depicts a cased wellbore ( 13 ), it should be noted that embodiments of the power source can be usable within any type of hole or opening, including cased or uncased wells, open holes, mines, platforms over subsurface openings, or other similar subsurface locations beneath land or water, as well as above-ground locations where production of a gas and/or pressure is desirable to actuate a tool and/or for other purposes. Additionally, while FIG. 1 depicts the wellbore ( 13 ) containing a packer ( 11 ), embodiments of a power source can be usable to actuate any type of subsurface tool, including without limitation, packers, plugs, cutters, setting tools, and other devices able to be actuated using pressure.
The packer ( 11 ) is shown in operative association with a setting tool ( 15 ), usable to actuate the packer ( 11 ). Exemplary setting tools can include such tools as Baker No. 10 and No. 20, from Baker Oil Tools. Another exemplary setting tool is described in U.S. Pat. No. 5,396,951, the entirety of which is incorporated herein by reference. Through actuation by the setting tool ( 15 ), the packer ( 11 ) can deploy sealing members ( 51 ) against the inner circumference of the wellbore ( 13 ).
A firing head ( 17 ) is shown coupled to the setting tool ( 15 ), the firing head ( 17 ) containing an embodiment of a power source (not visible in FIG. 1 ). The power source within the firing head ( 17 ) can be operatively coupled with a movable member of the setting tool ( 15 ) (e.g., a movable piston ( 43 ), shown in FIG. 2 ), such that gas produced by the power source can apply, to the setting tool ( 15 ), a pressure sufficient to cause actuation of the setting tool ( 15 ). An electrical conduit ( 45 ) is shown connecting the firing head ( 17 ) to a source of power (not shown) disposed at the surface ( 16 ), for ignition of the power source. Other sources of power, such as batteries, a downhole source of power, a mechanical source of power, or similar sources of power, can be usable, such that a electrical connection between the firing head ( 17 ) and the surface ( 16 ) is not required.
Referring now to FIG. 2 , an embodiment of a power source ( 21 ), usable within the scope of the present disclosure, is shown, disposed within the firing head ( 17 ). The power source ( 21 ) is depicted including a quantity of thermite ( 23 ), partially encased by a polymer ( 25 ), the polymer ( 25 ) defining a bottom wall ( 31 ) and a side wall ( 33 ). In one or more embodiments, the bottom wall ( 31 ) and/or the side wall ( 33 ) can be omitted, and the thermite ( 23 ) can be pressed against a stop or wall within the firing head ( 17 ) or against the setting tool ( 15 ).
The top of the thermite ( 23 ) is shown enclosed by a cap ( 41 ). The firing head ( 17 ) can also include an outer cap ( 42 ), which is shown enclosing the power source ( 21 ) contained within, enabling the entirety of the pressure produced by the power source ( 21 ) to be contained for actuating a movable member, shown as a piston ( 43 ) within the setting tool ( 15 ), by causing pressure produced by the power source ( 21 ) to be directed in a downhole direction. A thermal generator ( 27 ) is shown disposed in contact with the thermite ( 23 ) for initiating the thermite reaction. An electrical conduit (such as that depicted in FIG. 1 ), or a similar source of energy can be usable to activate the thermal generator ( 27 ). A typical thermal generator can produce heat sufficient to ignite the thermite ( 23 ) responsive to electrical current. An exemplary thermal generator is shown and described in U.S. Pat. No. 6,925,937, the entirety of which is incorporated herein by reference. Usable thermal generators can include any source of heat for initiating the thermite reaction, including, without limitation, direct contact between heating elements and the thermite or use of a heat source in communication with a separate controlled quantity of thermite used to initiate the thermite reaction within the power source ( 21 ).
While the polymer ( 25 ) is shown having the structural form of a container or sleeve for containing or otherwise partially or wholly enclosing the thermite ( 23 ), the polymer ( 25 ) can be combined with the thermite ( 23 ) in any manner that permits the polymer ( 25 ) to produce gas responsive to the thermite reaction.
Thermite includes a mixture of powdered or finely divided metals and metal oxides that reacts exothermically when ignited. The resulting thermite reaction is classified as non-explosive, the reaction occurring over a period of milliseconds, rather than nanoseconds. Specifically, thermite can include powdered aluminum, magnesium, chromium, nickel, or other similar metals, mixed with cupric oxide, iron oxide, or other similar metal oxides. In a preferred embodiment, the thermite ( 23 ) includes a mixture of aluminum and cupric oxide.
The polymer ( 25 ) can include any polymer or copolymer that produces gas responsive to the thermite reaction, and preferably produces a gas that slows the thermite reaction and/or reduces heat transfer of the thermite reaction. Such polymers can include, without limitation, polyethylene, polypropylene, polystyrene, polyester, polyurethane, acetal, nylon, polycarbonate, vinyl, acrylin, acrylonitrile butadiene styrene, polyimide, cyclic olefin copolymer, polyphenylene sulfide, polyketone, polyetheretherketone, polyetherimide, polyethersulfone, polyamide imide, styrene acrylonitrile, cellulose propionate, diallyl phthalate, melamine formaldehyde, or combinations thereof.
The quantity of polymer ( 25 ) within the power source ( 21 ) can be varied, in relation to the quantity of thermite ( 23 ), e.g., depending on the subsurface tool to be set and/or other purpose for which the power source is used. For example, when setting a packer, approximately 25% more polymer than thermite, by weight, can be used. In other embodiments, the quantity of polymer can range from 110% the quantity of thermite to 250% the quantity of thermite, by weight. It should be understood, however, that any quantity of polymer in relation to the quantity of thermite can be used, depending on the desired characteristics of the power source and the pressure to be produced.
In an embodiment, the power source ( 21 ) can include an accelerant (not shown), such as magnesium, mixed or otherwise associated with the thermite ( 23 ) and/or the polymer ( 25 ).
In one possible method of use, electrical current can be provided to the thermal generator ( 27 ), via the electrical conduit (depicted in FIG. 1 ) or using another similar source of power. Once the thermal generator ( 27 ) reaches the ignition temperature of the thermite ( 23 ), the thermite ( 23 ) begins to react. Heat from the thermite reaction heats the polymer ( 25 ), which causes the polymer to produce gas, which is at least partially consumed by the thermite reaction, thereby slowing the reaction. Absent the polymer ( 25 ), the thermite could potentially react rapidly, in a manner of seconds or less. Through use of the polymer ( 25 ) to attenuate the reaction, the thermite reaction can occur over several minutes, generally from one to three minutes in an embodiment. The gas produced by the polymer ( 25 ) can further increase the overall gas pressure produced by the thermite reaction.
The gas from the polymer ( 25 ) and/or the thermite reaction, confined by the outer cap ( 42 ), can breach the bottom wall ( 31 ) to apply pressure to the piston ( 43 ), thereby actuating the subsurface tool ( 15 ). The thermite reaction is not temperature sensitive, thus, the power source ( 21 ) is unaffected by the temperature of the downhole environment, enabling a reliable and controllable pressure to be provided by varying the quantity of thermite ( 23 ) and polymer ( 25 ) within the power source ( 21 ). Through provision of a “slow set” to a packer or similar tool, such as a continuous pressure for a period of one minute or longer, elastomeric sealing elements can obtain a greater holding capacity than sealing elements that are set more rapidly.
Subsequent to the thermite reaction, the thermite ( 23 ) and polymer ( 25 ) can be substantially consumed, such that only ash byproducts remain. The quantity of thermite ( 23 ) and/or polymer ( 25 ) can be configured to vary the reaction rate and the pressure provided by the reaction. For example, the length of the firing head ( 17 ) can be extended to accommodate a larger quantity of thermite ( 23 ) and/or polymer ( 25 ) when a longer reaction is desired. Similarly, a longitudinal hole or similar gap can be provided within the thermite ( 23 ) to shorten the reaction time.
While various embodiments have been described with emphasis, it should be understood that within the scope of the appended claims, the present invention might be practiced other than as specifically described herein. | Power sources and methods for applying a force to an object include use of thermite in a quantity sufficient to generate a thermite reaction, and a gas producing substance disposed in association with the thermite. The gas producing substance produces a gas when the thermite reaction occurs. The thermite reaction, the gas, or combinations thereof provide a force to the object. The gas can slow the thermite reaction to enable slower or continuous application of force while being non-extinguishing of the thermite reaction. The gas can further control heat transfer from the thermite reaction to adjacent objects. | 4 |
The present application hereby claims priority under 35 U.S.C. §119 on European patent application number EP 02002719.9 filed Feb. 6, 2002, the entire contents of which are hereby incorporated herein by reference.
FIELD OF THE INVENTION
The invention generally relates to a fluid-flow machine which includes a casing. Preferably, the casing includes a rotationally mounted rotor with three blade regions which are fluidically connected. It also generally relates to a method of operating the fluid-flow machine as a steam turbine.
BACKGROUND OF THE INVENTION
Known fluid-flow machines which have a high-pressure and a low-pressure-steam region may be of single-cylinder or two-cylinder construction. Such fluid-flow machines, in particular steam turbines, are shown in 1997P03012 DE. The two-cylinder design does not belong to the technical field of the present invention and is therefore not described in more detail. The single-cylinder design consists of a rotor having two single-flow blade regions which point toward the respective casing ends. One blade region is designed as a high-pressure-steam blade region and another blade region is designed as a low-pressure-steam region. Inflowing live steam flows in the axial direction first of all through the blade region of the high-pressure-steam blade region. From there, the steam, which is now partly expanded, passes via a line to the intermediate-pressure-steam blade region.
In the high-pressure and intermediate-pressure regions, the specific volume, at a constant mass flow, increases relatively slightly in the course of the expansion. Starting from the transition region between intermediate pressure and low pressure (about 2 to 3 bar), the specific steam volume increases sharply, and the volumetric flow and thus the requisite flow area likewise increase sharply. Physical limits (e.g. strength) are encountered when realizing the flow area and this involves considerable construction outlay.
A disadvantage with these known embodiments having a high-pressure expansion region is that superheated steam comes in contact with the interior of a turbine end. To reduce the amount of steam escaping from the turbine, a plurality of sealing shells are arranged between outer casing and rotor. The high-energy steam between the sealing shells is partly fed back into blading regions of lower temperature for the thermodynamic optimization of the process. In this case, the introduction of the sealing shell steam into the blading regions leads to asymmetrical casing heating at the casing circumference, and this asymmetrical casing heating results in thermal stresses and deformations, i.e. distortion of the casing, which may possibly lead to grazing of blades on the casing.
SUMMARY OF THE INVENTION
An object of an embodiment of the present invention is therefore to design a single-cylinder fluid-flow machine in such a way that no feedback of sealing shell steam with regard to thermodynamic optimization of the process is necessary.
A further object of an embodiment of the invention is to specify a method of operating a steam turbine.
According to an embodiment of the invention, the object which relates to the fluid-flow machine may be achieved in that the fluid-flow machine has an outer casing in which a rotor with three blade regions is mounted in a rotational manner, one of the blade regions being an inner region and the other blade regions being outer regions, through which blade regions a flow medium flows in a respective direction of flow during operation, the inner blade region being enclosed by the outer blade regions along the rotor, and the directions of flow in the outer blade regions being opposed to one another and being directed away from the inner region.
This configuration, for the first time, takes advantage of the fact that, by the above-described arrangement of the blade regions, an outflowing flow medium with virtually identical characteristic quantities such as pressure, temperature and volumetric flow discharges at the outer casing ends. Due to the low discharge parameters of the steam at the two casing ends, the arrangement of sealing shell systems with feedback of sealing shell steam into the blade regions is not necessary. Asymmetrical heating at the casing circumference due to the introduction of sealing shell steam is ruled out.
The compact design of the fluid-flow machine leads to further advantages in production, which lead to material and time savings. The material and time saving may be attributed, inter alia, to a design of the components in a reduced form. The use of less material leads to components of smaller mass and thereby to better start-up and operating behavior; in particular the reduction in size of the last blade stages is advantageous here.
Due to the smaller mass, the moment of inertia of the rotor changes. As a result, the start-up time is reduced.
In an advantageous development, the flow medium, after flowing through the inner blade region, is divided into two partial flows via a backflow passage. One of the partial flows flows through the backflow passage.
It is advantageous to provide the backflow passage with an axial compensator for compensating for thermal expansions. Temperature-induced outer casing stresses are thereby avoided. The axial compensator, for example, may include a bellows or the like.
The impingement of the flow medium on the rotating blade regions leads to a force acting in the axial direction. This force is called axial thrust. To compensate for the axial thrust, the rotor, in an advantageous development, is designed with a shaft step provided in front of the inner blade region.
A considerable advantage in this case results from the simple cost-effective integration in the casing.
To reduce leakages between the outer casing ends and the rotor, sealing shells with labyrinth seals or the like are arranged.
The fluid-flow machine preferably has an inflow region in which the flow medium is expanded in an adjoining expansion region by a control stage. The pressure of the flow medium in the expansion region is expanded to a wheel space pressure by a control stage. This control method provides for a rapid and precise means of controlling the fluid-flow machine and leads to good operating behavior.
An advantageous development is the design of the fluid-flow machine as a steam turbine.
The fluid-flow machine may be advantageously designed as an axial-flow compressor.
The object which relates to the method may be achieved according to an embodiment of the invention by the description of a method for operating a steam turbine. The steam turbine is designed with a rotationally mounted rotor having three blade regions, one of the blade regions being an inner region and the other blade regions being outer regions, through which blade regions a flow medium flows in a respective direction of flow during operation, the inner blade region being enclosed by the outer blade regions along the rotor, and the flow medium, after flowing through the inner blade region, being divided into two partial flows. After the division into the two partial flows, the one partial flow flows through an outer blade region and the other partial flow flows through the other blade region.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is explained in more detail below with reference to exemplary embodiments which are shown schematically in the drawings.
For the same and functionally identical components, the same designations are used throughout. In the drawings:
FIG. 1 shows a schematic longitudinal section through a fluid-flow machine;
FIG. 2 shows a representation of the basic mode of operation of a turbine and an axial-flow compressor.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
FIG. 1 shows a schematic longitudinal section through a fluid-flow machine 1 having an outer casing 2 , a plurality of inner casings 11 , 12 , 16 , 21 and a rotor 3 . Four blade regions 4 , 5 , 6 , 7 are arranged on the rotor 3 . In this exemplary embodiment, the four blade regions are divided into two inner blade regions 5 , 6 and two outer blade regions 4 , 7 . The two outer blade regions 4 , 7 are arranged in opposition to one another and point away from the inner blade regions 5 , 6 .
Upstream of the first inner blade region 5 , an inflow opening 8 is contained in the outer casing. A control stage 9 is provided starting from the inflow opening 8 in the direction of the first inner blade region 5 . An expansion region 31 follows the control stage 9 in the direction of the first inner blade region 5 . In the exemplary embodiment presented, guide blades 10 are attached to the inner casing 11 in the first inner blade region 5 .
Following the first inner blade region 5 is a further inner blade region 6 . In the second inner blade region 6 , further guide blades 13 are attached to a further inner casing 12 . One or more outlet openings 14 are contained between the second inner blade region 6 and an outer blade region 7 . At the outer blade region 7 , further guide blades 15 are fixed to a further inner casing 16 .
Located in the outer casing 2 between a further outer blade region 4 and the inflow region 8 is an inflow opening 32 which is fluidically connected to the outlet opening 14 via a backflow passage 19 . In the region of the outer blade region 4 , further guide blades 20 are located in a further inner casing 21 .
The backflow passage 19 is provided with an axial compensator 22 in order to compensate for thermal stresses between the backflow passage 19 and the outer casing 2 .
The rotor 3 is designed with a shaft step 23 in order to compensate for the axial thrust of the rotor 3 .
Sealing shells 24 a and 24 b are arranged between the rotor 3 and the outer casing 2 in order to reduce the leakage from the fluid-flow machine.
During operation, a flow medium flows via the inflow opening 8 into the fluid-flow machine 1 . From there, the flow medium passes to the control stage 9 , where the pressure is expanded to a wheel space pressure. The flow medium then flows through the first blade region 5 . In the exemplary embodiment shown, the flow medium then flows through the second blade region 6 . Downstream of this second blade region 6 , the flow medium is separated into two partial flows 18 , 33 by way of one or more openings 14 . The partial flow 33 flows through the outer blade region 7 . The second partial flow 18 flows via the backflow passage 19 into an inflow opening 32 . From there, the partial flow flows through the further outer blade region 4 . After flowing through the outer blade regions 4 , 5 , both partial flows pass out of the fluid-flow machine 1 via outlet openings 17 a , 17 b.
Due to the separation of the flow medium into two partial flows 18 , 33 and due to the arrangement shown of the blade regions 4 , 5 , 6 and 7 , the individual partial flows of the separated flow medium reach the outer blade regions 4 , 7 with virtually identical characteristic quantities such as pressure, temperature and volumetric flow. A resulting advantage is the symmetrical casing heating. Due to the low state variables of the flow medium in these regions, smaller thermal deformations occur, and the operating reliability of the fluid-flow machine increases. The design of the sealing shells between outer casing and rotor is advantageous for reducing the leakage without feedback of sealing shell steam between the blading regions.
The compact single-cylinder design results in further advantages in production and in the start-up and operating behavior. In this case, advantage is taken of the fact that material can be saved. In particular, the last blade stages can be produced in smaller sizes.
The operating principle of the fluid-flow machine 1 according to an embodiment of the invention is shown in FIG. 2 . The fluid-flow machine may be designed as a steam turbine on the one hand and as an axial-flow compressor on the other hand.
In a design as a steam turbine, the operating principle is as described below. Via a steam generator 25 , superheated steam 26 passes via a feed line 27 into a steam turbine interior 28 . After flowing through the above-described blade regions 4 , 5 , 6 and 7 in the steam turbine interior 28 , the superheated steam is expanded and flows via a discharge line 29 to a condenser 30 . The rotation of the rotor 3 may be used for generating electrical energy.
In a design as an axial-flow compressor, the operating principle is as described below. By forced rotation of the rotor 3 , atmospheric air or the like in an inlet opening 30 a is fed via a feed line 29 a into an axial-flow-compressor interior 28 a . In the axial-flow-compressor interior 28 a , by a direction of rotation of the rotor 3 and thus of the above-described blade regions 4 , 5 , 6 and 7 which is reversed compared with the steam turbine, the atmospheric air is compressed and passes via a line 27 a in a highly compressed manner to an outlet 25 a.
LIST OF REFERENCES
1 Fluid-flow machine
2 Outer casing
3 Rotor
4 Outer blade region
5 Inner blade region
6 Inner blade region
7 Outer blade region
8 Inflow opening
9 Control stage
10 Guide blades
11 Inner casing
12 Inner casing
13 Guide blades
14 Outlet openings
15 Guide blades
16 Inner casing
17 a, b Outlet openings
18 Second partial flow
19 Backflow passage
20 Guide blades
21 Inner casing
22 Axial compressor
23 Shaft step
24 a, b Sealing shells
25 Steam generator
26 Superheated steam
27 Feed line
28 Steam turbine interior
29 Discharge line
30 Condenser
31 Expansion region
32 Inflow opening
33 First partial flow
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. | A fluid-flow machine includes an outer casing having a rotationally mounted rotor with three blade regions. The blade regions are divided into an inner blade region and two outer blade regions, the two outer blade regions pointing outward toward the outer casing end. The fluid-flow machine includes one or more outlet openings, via which the flow medium is divided into two partial flows. The two partial flows then flow through the respective outer blade regions. | 5 |
RELATED APPLICATIONS
[0001] This application is a continuation of U.S. patent application Ser. No. 13/612,522, filed on Sep. 12, 2012, which is a continuation of U.S. patent application Ser. No. 12/463,051, filed on May 8, 2009, which is a continuation of U.S. patent application Ser. No. 10/546,104, filed on Jul. 19, 2006, which is a U.S. National Phase Application of International Application No. PCT/US04/05153, filed Feb. 20, 2004, which claims priority of U.S. Provisional Patent Application No. 60/449,545, filed on Feb. 21, 2003.
[0002] This application is also a continuation of U.S. patent application Ser. No. 12/463,051, filed on May 8, 2009, which is a continuation of U.S. patent application Ser. No. 10/546,104, filed on Jul. 19, 2006, which is a U.S. National Phase Application of International Application No. PCT/US04/05153, filed Feb. 20, 2004, which claims priority of U.S. Provisional Patent Application No. 60/449,545, filed on Feb. 21, 2003.
[0003] U.S. patent application Ser. No. 13/612,522 published as U.S. Publication No. 2013/0000628 on Jan. 3, 2013; U.S. patent application Ser. No. 12/463,051 published as U.S. Publication No. 2009/0223503 on Sep. 10, 2009; U.S. patent application Ser. No. 10/546,104 published as U.S. Publication No. 2007/0006865 on Jan. 11, 2007; and International Application No. PCT/US04/05153 published as International Publication No. WO 2004/076928 on Sep. 10, 2004. The entire contents of each of the foregoing applications and publications are hereby incorporated by reference.
FIELD OF THE INVENTION
[0004] The present invention relates to a gas-fired tunnel oven, and particularly a gas-fired conveyor oven.
BACKGROUND
[0005] Commercial, gas-fired tunnel ovens equipped with conveyors produce, among other things, pizzas, cookies, bread, cakes and donuts. Each oven routinely processes a large volume of food products and, as a result, becomes rather dirty. Bits of the food products themselves, burned food products, and soot from the burners are typical sources of contamination that accumulate during use.
[0006] Gas-fired tunnel ovens traditionally have been cleaned manually with detergent and acid solutions. The oven must be taken apart for cleaning by these methods. In addition to the oven walls, roof, and floor, the conveyor used with the tunnel oven must be cleaned, as well as any jet-impingement convection fingers, convection blowers, and fired burners. Cleaning by the traditional methods is tedious and expensive.
SUMMARY
[0007] In theory, a gas-fired, commercially-sized tunnel oven might be cleaned by installing electrical heaters at critical points to raise the internal temperature to a range that reduces virtually all contamination to ash. In practice, cleaning a gas-fired tunnel oven by raising the temperature with electrical heaters requires an estimated 50-100 amperes of electricity for each oven. Commercial bakers do not normally have access to this much electrical current, and the cost of installing high current electrical service is a significant financial barrier for most bakers.
[0008] Accordingly, there is a need for a self-cleaning, gas-fired tunnel oven suitable for use with a conveyor that can be cleaned without need of disassembly, manual cleaning, or detergents. Commercial bakers would welcome a self-cleaning, gas-fired tunnel oven.
[0009] In some embodiments, a conveyor oven having a first mode of operation and a second mode of operation is provided. The conveyor oven generally includes an oven chamber in which food is cooked, a conveyor movable to convey the food through the oven chamber, a burner to generate heat for the oven chamber, at least one blower to circulate air within the oven chamber, and a controller. The burner has a combustion airflow rate, and operates at a first output during the first mode of operation and at a second output that is greater than the first output during the second mode of operation. The blower operates at a first speed during the first mode of operation and at a second speed that is faster than the first speed during the second mode of operation. The controller is responsive to at least one of a burner output and an internal temperature of the oven chamber, and increases the speed of the blower from the first speed during the first mode of operation to the second speed during the second mode of operation responsive to at least one of an increase of the burner output and an increase of the internal temperature of the oven chamber.
[0010] Also, in some embodiments, a conveyor oven generally includes an oven chamber in which food is cooked, a conveyor movable to convey the food through the oven chamber, a gas burner configured to generate heat for the oven chamber, at least one blower to circulate air within the oven chamber, and a controller. The gas burner has an adjustable combustion airflow rate and an adjustable gas flow rate. The controller is responsive to at least one of a burner output and an internal temperature of the oven chamber, and increases the combustion airflow rate response to at least one of an increase in the burner output and an increase in the internal temperature of the oven chamber.
[0011] Other aspects of the invention will become apparent by consideration of the detailed description and accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0012] FIG. 1 is a perspective view of a self-cleaning oven with both first and second conveyor extension sections extended, each of the conveyor sections being depicted without its mesh belt for clarity;
[0013] FIG. 2 is a partial perspective view of the oven of FIG. 1 showing a drive shaft, a main conveyor section and the first and second conveyor extension sections, each of the conveyor sections being depicted without its mesh belt for clarity;
[0014] FIG. 3 is a side view of the oven of FIG. 1 with one of the side walls removed, showing one of the blower and motor assemblies and two air-impingement fingers;
[0015] FIG. 4 is a perspective view of the oven of FIG. 1 with the first conveyor extension section extended and the second conveyor extension section retracted, the first conveyor extension section being shown without its mesh belt for clarity;
[0016] FIG. 5 is a view of the oven of FIG. 1 with the front access door removed, showing both conveyor extension sections in their retracted positions;
[0017] FIG. 6 is a front elevation view of the oven of FIG. 1 with both conveyor extension sections retracted;
[0018] FIG. 7 is an overhead perspective view of the oven of FIG. 1 with the ceiling and overhead insulation removed, showing a roof-mounted burner assembly, two blower and motor assemblies, and a vent arrangement;
[0019] FIG. 8 is a close-up perspective view of the burner assembly of FIG. 3 showing a gas shut-off valve, a gas valve, an air valve, a valve link that coordinates the action of the gas valve with the action of the air valve, and a burner;
[0020] FIG. 9 is a rear perspective view of the oven of FIG. 1 showing the two blowers and the vent arrangement; and
[0021] FIG. 10 is a perspective view of walls and a tubular frame support surrounding a cooking chamber of the oven of FIG. 1 .
[0022] FIG. 11 is a partial perspective view of the oven of FIG. 1 showing a drive shaft, the main conveyor section and the first conveyor extension section, each of the conveyors depicted without its mesh belt for clarity.
[0023] FIG. 12 is an overhead view of the oven of FIG. 1 with the ceiling and overhead insulation removed, showing a roof-mounted flame tube assembly and two blower and motor assemblies.
[0024] FIG. 13 is a view of the main conveyor section through an oven opening with one of the conveyor extension sections removed.
[0025] FIG. 14 is a view of the main conveyor section and its connection to the front wall of the oven depicted in FIG. 1 .
[0026] FIG. 15 is a view of one of the conveyor extension sections separated from the oven of FIG. 1 .
[0027] FIG. 16 is a side view of the mesh belt of one of the conveyor extension sections.
DETAILED DESCRIPTION
[0028] According to one embodiment, a pyrolytically self-cleaning, gas-fired, conveyor oven 10 , as shown in FIG. 1 , includes an oven housing 12 supported on four legs 14 . The oven housing 12 surrounds a cooking chamber 16 through which food products are passed on a conveyor assembly 18 . The oven 10 also includes a front access door 40 that can be opened using a front access door handle 41 .
[0029] As best seen in FIG. 2 , the conveyor assembly 18 includes powered rollers 20 that drive a wire mesh conveyor belt (not shown in the Figures) that conveys food through the cooking chamber 16 . The powered rollers 20 can be driven in either direction so that, as viewed in FIG. 2 , the conveyor belt can convey food through the cooking chamber 16 from left-to-right or right-to-left. Food products can be transported by the conveyor assembly 18 into a first oven opening 37 and out of a second oven opening 38 or, alternatively, into the second oven opening 38 and out of the first oven opening 37 . In either case, the motion of the conveyor drive motor (not shown) and, consequently, the motions of the conveyor assembly 18 are precisely and continuously controlled in order to provide the optimum cooking time for the food products. The speed and direction of the conveyor assembly 18 are input by an operator through a control station (not shown).
[0030] As the oven 10 is shown in FIGS. 1 and 2 , it is configured for cooking food products. That is, the conveyor assembly 18 extends out of the cooking chamber 16 at both ends. Food is placed on the conveyor assembly 18 at either end of the oven 10 and is carried through the cooking chamber 16 to the other end of the oven 10 . As best seen in FIG. 2 , the conveyor assembly 18 includes a main conveyor section 30 and first and second conveyor extension sections 32 , 34 extending out of the cooking chamber 16 . Over time, as food products travel back and forth over the conveyor assembly 18 , the various sections 30 , 32 , 34 of the conveyor assembly 18 clog with food debris and otherwise become dirty. Additionally, food particles that drop onto various surfaces and components within the cooking chamber 16 become dirty. To clean the oven 10 , the first and second conveyor extension sections 32 , 34 can be disconnected from the main conveyor section 30 and inserted into the cooking chamber 16 .
[0031] The main conveyor 30 is driven by a direct current electric motor operating through a gear reducer. A pulse-controlled conveyor drive motor (not shown) turns a drive shaft 86 which is rigidly attached to a drive gear 88 , which are depicted in FIG. 11 . The drive motor sends well-defined pulses of electrical energy to move the drive shaft 86 in either a clockwise or counterclockwise direction. Each electrical pulse of the motor moves the drive shaft 86 a reproducible increment. For example, a single pulse may be adjusted to advance the drive shaft 86 by a predetermined number of angular degrees. The frequency of electrical pules determines the speed of the drive shaft 86 , and consequently the speed of the conveyor assembly 18 , in either direction. The drive gear 88 turns the main conveyor section 30 and the first and second conveyor extension sections 32 , 34 by means of follower gears 90 , 92 (only one is shown for the first conveyor extension section 32 ). The follower gears 90 , 92 cause conveyor axles 110 to turn, which creates the conveyor motion. The speed of all the conveyor sections, and ultimately, the cooking time of food products traveling through the oven 10 , is regulated by the drive motor. The drive motor for oven 10 is controlled by a digital control unit (not shown).
[0032] FIGS. 1 and 2 depict both the first conveyor extension section 32 and the second conveyor extension section 34 in an extended and locked position, the conveyor extension sections 32 , 34 being both collapsible and extendable. The first conveyor extension section 32 is accompanied by a first insulated door 35 and the second conveyor extension section 34 is accompanied by a second insulated door 36 . Both the first and second conveyor extension sections 32 , 34 can be separated from the oven housing 12 and inserted into a first oven opening 37 and a second oven opening 38 , respectively. After the conveyor extension sections 32 , 34 have been inserted into the oven housing 12 , the first insulated door 35 can be shut to close the first oven opening 37 and the second insulated door 36 can be shut to close the second oven opening 38 .
[0033] FIG. 11 is a partial perspective view of oven 10 in which only selected components are shown in order to better communicate the invention. FIG. 11 shows the relationship of the main conveyor section 30 to the first conveyor extension section 32 when the first conveyor extension section 32 is in the extended position. The first and second conveyor extension sections 32 , 34 (only one is shown in FIG. 11 ) each include an upper notch 78 , sized and shaped to receive an upper peg 80 , which is attached to an inside wall of the oven (not shown in FIG. 11 ). The first and second conveyor extension sections 32 , 34 also each include a lower notch 82 for receiving a lower peg 84 , which is also attached to the inside wall (not shown). Lifting the first and second conveyor extension sections 32 , 34 causes them to rotate about the upper pegs 80 until the lower pegs 84 disengage from the lower notches 82 .
[0034] With the lower notches 82 disengaged, the first and second conveyor extension sections 32 , 34 can be separated from oven 10 and inserted into the first and second oven openings 37 , 38 so that the first and second insulated doors 35 , 36 close the first and second oven openings 36 , 38 , as shown in FIG. 6 .
[0035] In order to assemble the conveyor assembly 18 for baking, the first conveyor section 32 is partially inserted into the first oven opening 37 and locked in an extended position with respect to the main conveyor section 30 . The first conveyor section 32 is locked by inserting the pair of upper notches 78 formed by the sides of the first conveyor section 32 under a pair of upper pegs 80 mounted in the oven 10 . A pair of lower notches 82 also formed by the sides of the first conveyor extension 32 are then rotated onto a pair of lower pegs 84 mounted in the oven 10 . The second conveyor extension section 34 is similarly inserted into the second oven opening 38 and locked in an extended position with respect to the main conveyor section 30 .
[0036] The first conveyor extension section 32 is separated from the oven 10 in FIG. 13 , providing a close-up view of the first oven opening 37 and the main conveyor section 30 . The drive shaft 86 of the main conveyor section 30 extends between two side plates 96 , although only one of the side plates 96 is visible in FIG. 13 . FIG. 13 also depicts five of the six drive sprocket wheels 100 attached to the conveyor axle 110 of the main conveyor section 30 . A mesh belt 102 is shown as an endless chain engaged with the drive sprocket wheels 100 . One of the upper pegs 80 and one of the lower pegs 84 , which cooperate for locking the first conveyor section 32 (not shown in FIG. 13 ) in an extended position, are also visible in FIG. 13 .
[0037] The sixth of the six drive sprocket wheels 100 of the main conveyor section 30 is shown in FIG. 14 along with one of the two side plates 96 . A bracket 106 extends from one of the side plates 96 and is fastened to the front wall 66 for supporting the main conveyor section 30 . The front wall 66 also supports one of the upper pegs 80 and one of the lower pegs 84 .
[0038] A close-up, partial perspective view of the first conveyor extension section 32 is presented in FIG. 15 . The mesh belt 102 of the first conveyor extension section 32 tends to sag if not supported, as illustrated in FIG. 16 . FIG. 15 depicts four guides 108 , which are provided to support the mesh belt 102 . The guides 108 are in turn supported by guide supports 98 , which extend the width of the first conveyor extension section 32 . FIG. 15 also shows the conveyor axle 110 and the six drive sprocket wheels 100 for the first conveyor section, which are used to facilitate the progress of the mesh belt 102 .
[0039] FIG. 4 shows the second conveyor extension section 34 inserted into the cooking chamber 16 and a second insulated door 36 closed to seal off the second oven opening 38 through which the second conveyor extension section 34 previously extended.
[0040] FIG. 5 further illustrates that the main conveyor section 30 supports the first conveyor extension section 32 when the first conveyor extension section 32 is inserted into the first oven opening 37 . Inserting the first conveyor extension section 32 into first oven opening 37 allows the first insulated door 35 to close the first oven opening 37 . Similarly, the main conveyor section 30 supports the second conveyor extension section 34 , when the second conveyor extension section 34 is inserted into the second oven opening 38 so that the second insulated door 36 can close the second oven opening 38 . With the insulated doors 35 , 36 closed, the cooking chamber 16 of the oven 10 is completely sealed, as shown in FIG. 6 . The cooking chamber 16 can then be superheated to approximately 900°, turning all food debris in the oven 10 to ash. When the food debris has been burned and turned to ash, the front access door 40 can be opened using the front access door handle 41 and the ash can be cleaned from the oven 10 .
[0041] As seen in FIGS. 13-16 each of conveyors includes endless stainless steel mesh belts 102 capable of traveling in either direction and at variable speeds. Crumb trays (not shown) are removably installed underneath the first and second conveyor extension sections 32 , 34 .
[0042] As food travels through the cooking chamber 16 , it is cooked by the impingement of hot air that is directed at the main conveyor section 30 through nozzles 22 located on fingers 24 . As shown in FIGS. 2 and 3 , the depicted conveyor oven 10 includes two fingers 24 , a lower finger having nozzles 22 directing air upward at the bottom of the conveyor assembly 18 and an upper finger having nozzles 22 (not seen in FIG. 2 ) directing air downward at the top of the main conveyor section 30 . The fingers 24 contain an inner distributor plate (not shown) and a perforated outer plate containing the nozzles 22 that collimate the heated air and evenly distribute the heated air across the main conveyor section 30 on which the food products ride. The oven 10 depicted in FIG. 3 includes two fingers 24 (one above the conveyor and one below), however, the oven 10 can accommodate a number of bottom fingers 24 and top fingers 24 . Any combination or deletion of fingers may be employed.
[0043] The hot air directed through the fingers 24 is heated by a burner assembly 42 (best seen in FIGS. 7 and 8 ) located under an instrument panel 39 ( FIG. 1 ) on the front of the oven 10 . The burner assembly 42 creates the heat used by the oven 10 during both cooking (baking) and self-cleaning The burner assembly 42 heats the hot air that flows through the fingers 24 to cook food products passing along the conveyor assembly 18 . The burner assembly 42 burns a gas and air mixture at a burner 44 , which shoots a flame down a flame tube 46 . The flame heats the air contained in the flame tube 46 , and the heated air exits the flame tube through an outlet 47 and into a plenum 94 , as seen in FIG. 12 . The open space of the plenum 94 , located in front of the back wall 70 of the oven 10 , provides the hot air with a directed passageway toward a blower housing 74 where it will be circulated throughout the cooking chamber 16 .
[0044] Because the burner 44 is called upon to satisfy a wide range of heat output requirements, it is necessary to control the flow of gas and air supplied to the burner 44 . While the burner 44 is operating, the flow of both air and heating gas to the burner 44 is modulated by a combined control system. With this combined modulating control system for combustion air and heating gas, optimum combustion conditions within the burner 44 can be maintained approximately constant over a range of heat outputs. With this combined modulating control system, the ratio of combustion air flow to heating gas flow can be optimized and maintained so that combustion is thermally efficient and environmentally sound, producing a minimum of objectionable byproducts.
[0045] The ratio of combustion air to heating gas can be optimized to produce, for example, environmentally clean burning and the ratio will remain close to the optimum value whether the programmable controller (not shown) calls for high heat or low heat. Alternatively, the ratio may be optimized for optimal fuel consumption, optimal heat-up time or any other results that the operator desires and the ratio will not vary substantially with heat output. This modulating control system for combustion air and heating gas over a range of heat output is especially advantageous for a self-cleaning oven, such as the oven 10 , where a range of heat outputs is required.
[0046] The burner assembly 42 includes an actuator 48 that operates an air valve 50 that regulates the amount of air entering the burner 44 from a combustion air blower 52 . The actuator 48 controls the position of the air valve 50 based on signals received from other control instruments and sensors (not shown) included in oven 10 . A valve link 54 coordinates the movement of the gas valve 56 with that of the air valve 50 . The gas valve 56 receives gas from an automatic gas shut-off valve 57 and modulates the flow of this gas so that the ratio of heating gas to combustion air is relatively constant for a wide range of heating loads. The valve link 54 connects the air valve 50 to the gas valve 56 so that as the actuator 48 opens and closes the air valve 50 , the gas valve 56 is correspondingly opened and closed, proportionally mixing the air and gas as they enter the burner 44 . The air and gas mixture is then ignited inside the burner 44 and a flame shoots down the flame tube 46 .
[0047] One of the advantages of modulating air and gas control, as provided by the valve link 54 , is that the amount of excess air in the flame tube 46 remains substantially the same during high and low heating load periods. This advantage is particularly important in a self-cleaning, pyrolitic oven, which exhibits a significantly higher heating load during self-cleaning than conventional cooking heating loads. Although the valve link 54 depicted in FIGS. 6 , 7 and 8 is mechanical, it is also contemplated that the positions of an air valve and a gas valve in modulating air and gas control systems may alternatively be coordinated by, for example, utilizing electronically-controlled actuators for each of the valves and coordinating their positions by means of one or more electronic controllers.
[0048] The burner 44 may be mounted anywhere in the oven. Preferably, the burner 44 is roof-mounted as shown and sends its flame along the inside of the flame tube 46 mounted adjacent the ceiling of the oven 10 . During operation of the oven 10 , contaminants tend to accumulate most heavily on and near the oven floors. Thus, the roof-mounted burner system is more likely to progressively incinerate—and less likely to ignite—the floor accumulation as compared to conventional floor-mounted and wall-mounted burner configurations.
[0049] During baking and self-cleaning operations, the flame tube 46 becomes very hot and radiates heat energy throughout the inventive oven 10 . It is contemplated that a diffusing tube (not shown) may be employed around the burner for processing food products that tend to discolor or otherwise deteriorate when subjected to intense radiant heat.
[0050] The oven 10 has two relatively large blowers 26 , 27 (see FIG. 7 ) to move the heated air created by the burner 44 through the fingers 24 and onto the product so that the most efficient bake is achieved for each food product processed in the oven 10 . More specifically, the oven 10 employs collimated, vertical air streams to give uniform and intensive heating. The collimated, vertical streams of air that emerge from the fingers 24 provide an exceptional heat transfer rate and generally bake foods faster and at lower temperatures than in conventional convection hot air or infrared heating ovens.
[0051] The hot air is circulated through the oven 10 by the two blowers 26 , 27 located at the back of the oven 10 (see FIG. 9 ). The two convection blowers 26 , 27 are located in the blower housing 74 (see FIG. 10 ). The blowers 26 , 27 are each powered by a blower motor 75 (only one is shown in FIG. 9 ), which is mounted on the back wall 70 , and connected to the blowers 26 , 27 by a shaft (not shown). In order to protect the shafts from the pyrolitic temperature of the self-cleaning operation, the shafts may be fitted with heat-slingers (not shown) or other cooling apparatuses. A heat slinger is a type of fan arrangement mounted on the shaft. Each blower motor 75 may be equipped with a dedicated speed controller (not shown), preferably including an electrical power inverter. With the benefit of individual speed control, the blowers 26 , 27 can be individually accelerated and decelerated to optimize electrical current inrush, the burner 44 firing or convective heat loss. The speed of the blowers 26 , 27 may also be individually controlled in order to create distinguishable heating zones within the oven 10 to optimize the baking of particular food products.
[0052] In another embodiment, the blowers 26 , 27 may be variable speed blowers that are controlled together so that their speeds, while variable, are always the same as each other.
[0053] There are also two cooling fans 13 , 15 located on the front of oven 10 as depicted in FIGS. 1 , 4 , 6 , and 7 . These fans blow cool air in through the machinery compartment and out the side walls. The cooling fans 13 , 15 draw air from the surroundings through the instrument panel 39 for cooling the instruments located behind the instrument panel 39 . A portion of the discharge air from the cooling fans 13 , 15 may enter the combustion air blower 52 and be delivered to the burner 44 as combustion air. The remainder of the discharge air from cooling fans 13 , 15 enters passages that extend between the external sheeting of the oven 10 and an inside wall, which supports insulation. The flow of air in these passages serves to cool the external sheeting of the oven 10 below preferably about 125 degrees F.
[0054] Referring to FIG. 9 , a vent arrangement 58 is located at the back of the oven 10 . The vent arrangement 58 includes a vent valve 60 that is positioned between a vent tube 62 and a T-shaped tube 64 that communicates with the high-pressure sides of the blowers 26 . During a normal cooking cycle, the vent valve 60 is closed so that no air passes through the vent valve 60 into the vent tube 62 . In this way, during cooking, air that is heated is directed solely into the cooking chamber 16 for efficient cooking of food in the cooking chamber 16 . However, when it is desired to clean the oven 10 , the vent valve 60 is opened and the oven openings 37 , 38 are closed, as discussed above. By opening the vent valve 60 , enough heated air is exhausted through the vent tube 62 to maintain a slight negative pressure within the cooking chamber 16 . In this way, the smoke and soot that develops during a self-cleaning cycle is exhausted through the vent tube 62 and the passage of smoke and soot through small openings and cracks in the oven housing 12 is prevented.
[0055] As shown in FIG. 10 , the cooking chamber 16 is bounded by a front wall 66 and two side walls 68 that are connected to a back wall 70 . The front wall 66 , two side walls 68 , and back wall 70 are all screwed together to form a box surrounding the cooking chamber 16 . The back wall 70 of this box is fixed to a tubular frame 71 , which is connected to a platform 72 . However, while the back wall 70 of the box is fixed to the tubular frame 71 , the front wall 66 , and two side walls 68 are free-floating. That is, the front wall 66 and two side walls 68 are connected to the back wall 70 , but are not connected to the tubular frame 71 . The perimeters of the front wall 66 and the two side walls 68 include lips 73 that sit on the various members that make up the tubular frame 71 , but are not fixedly connected to those members. In this way, the front wall 66 and two side walls 68 are free to move relative to the tubular frame 71 so that during cooking, and particularly during self-cleaning when the temperatures in the cooking chamber 16 are relatively high, the front wall 66 and side walls 68 of the cooking chamber 16 are free to expand and slide on the members of the tubular frame 71 , thereby preventing buckling and warping of the walls of the cooking chamber 16 .
[0056] A unified display control station (not shown) for the oven 10 can include a blower selector, a heat selector, a conveyor selector, two or more conveyor speed controllers and a digital temperature controller. Additionally, a machinery compartment access panel safety switch disconnects electrical power to the controls and the blowers when the machinery compartment access panel is opened.
[0057] In order to start up the oven 10 , an operator confirms that the front access door 40 is closed. The operator then turns the blower and conveyor selectors to the “on” position. If necessary, the operator adjusts the conveyor speed setting by pushing appropriate selectors on the conveyor speed controller. The operator adjusts the temperature controller to a desired temperature and selects normal operation. A heat switch on a control station (not shown) of the oven 10 activates the combustion air blower 52 . The burner 44 is a direct ignition burner. The main gas valve 57 is opened while starting a spark in the burner 44 . A sensor then monitors whether a flame is present within the burner 44 . If a flame is not detected within 6 seconds, the main gas valve 57 is shut down, the burner 44 is purged, and the ignition cycle is repeated. Referring to FIGS. 7 and 8 , a gas bypass tube 76 provides enough gas to the burner 44 to maintain a minimum flame even when the gas modulation valve 56 is closed.
[0058] The oven 10 will typically heat to a desired heating set-point temperature within a matter of minutes. While the oven 10 is heating, the control station (not shown) displays the actual temperature. One or more thermocouples (not shown) in the interior of the oven 10 send signals to a programmable controller (not shown) that controls the actuator 48 . If the programmable controller (not shown) calls for more heat, the actuator 48 rotates to open the air valve 50 and more combustion air is permitted to pass from the combustion air blower 52 to the burner 44 . Simultaneously, the valve link 54 moves under the influence of the actuator 48 to further open the gas valve 56 , permitting more heating gas to pass from gas line 55 to the burner 44 . If the programmable controller (not shown) calls for less heat, the valve link 54 causes the air valve 50 and the gas valve 56 to close simultaneously and proportionally. Consequently, the ratio of combustion air flow to heating gas flow entering the burner 44 remains approximately constant over a range of heat output.
[0059] As mentioned, the speed of the blowers 26 , 27 can be varied. For example, the speed of the blowers may be two-thirds full speed during start-up and self-cleaning cycles and full speed during a cooking cycle to promote heating efficiency during each of the cycles. For heating the oven 10 to baking or self-cleaning temperatures, one or both of the blower motors 75 (only one is shown in FIG. 9 ) start and routinely ramp up to a desired operating speed in a programmable period of time. Programming the start-up time of convection blower motors 75 makes firing of the burner 44 more reliable and promotes better combustion, among other things. When the blowers 26 , 27 are turning, the burner 44 is initially fired with a minimum heat output and ramped up to the baking or self-cleaning heat output over a period of time by, for example, a programmable controller (not shown). When the desired heat output has been achieved, the blower motors 75 are accelerated to operating speed in a programmable period of time.
[0060] The start-up procedure (i.e., ramping up the speed of one or both of the blowers 26 , 27 ) prevents an objectionable current inrush situation that is observed in conventional ovens, which commonly start two or more blower motors at full speed simultaneously. This startup procedure is also quieter, and requires less electricity and heating gas, than the startup of conventional ovens. Because the blowers 26 , 27 draw more electrical current when the oven is cold and the air in the oven is relatively dense, operating both blowers at low speed during heat-up (start-up) saves electricity. Also, because increased convection on the inside surfaces of the oven walls promotes heat loss to the kitchen, operating only one of the convection blowers during heat-up saves heating gas.
[0061] Preferably, each of the blowers 26 , 27 is equipped with an electrical power inverter (not shown), which alters the frequency and/or voltage of the electrical current to control the speed of the blower 26 or 27 . In that case, the blower motor 75 can be either ramped up to operating speed over a programmable period such as, for example, about thirty minutes, or held at an optimal intermediate speed until the oven 10 reaches baking or cleaning temperature and then accelerated. These variations conserve still more energy by providing appropriate programmable blower speeds depending on the current operation of the oven 10 . When the oven 10 is, for example, baking (cooking), self-cleaning, warming up, or cooling down, the blowers 26 , 27 can operate at specific speeds best suited for each individual activity.
[0062] Furthermore, for baking, the speed of the blower motors 75 (only one is shown in FIG. 9 ) may be separately adjusted to create two or more different heating zones (not shown) within the oven 10 . These heating zones (not shown) can be created at will and utilized to optimize the baking process and, consequently, the finished quality of a particular food product. The oven 10 may be equipped with two or more thermocouples (not shown) or other temperature sensors to individually monitor and adjust these heating zones (not shown). The manner in which the signals from these thermocouples (not shown) are averaged or otherwise interpreted by the programmable controller can be varied to suit the food product.
[0063] In order to shut down the blowers 26 , 27 , the operator selects standby on the control station. The blowers 26 , 27 will remain in operation until the oven 10 has cooled to below 200 degrees F. and then cease turning.
[0064] When it is determined that the oven 10 should be cleaned, it is cooled to a temperature below about 140 degrees F. The operator then disengages the first conveyor extension section 32 and withdraws the first conveyor extension section 32 from the first oven opening 37 . The first conveyor extension section 32 is then inserted into the first oven opening 37 so that the first conveyor extension section 32 is supported by the main conveyor section 30 and the first insulated door 35 closes the first oven opening 37 . The second conveyor extension section 34 is similarly separated from the oven 10 and inserted into the second oven opening 38 and the second insulated door 36 is closed. Because the first and second conveyor extension sections 32 , 34 are inserted into the interior of the oven 10 , they are cleaned by pyrolitic heat during the self-cleaning cycle. The vent valve 60 (best seen in FIG. 9 ) is opened and the blowers 26 , 27 are then brought up to operating speed and the burner 44 is fired to raise the oven 10 to self-cleaning temperature. During the self-cleaning cycle, oven 10 operates under the control of temperature sensors and controllers (not shown) that are specifically designed to operate in the range of about 650-1000 degrees F. These may be the same sensors and controllers used for baking (not shown) or a separate set.
[0065] In either case, the programmable control system actuates a set of safety interlocks adapted for cleaning temperature operation. For example, the oven overrides the baking cycle high temperature shutdown limits, which are typically set at values less than 600 degrees F. As another example, the programmable control system actuates door locks that deter people from opening the oven doors during the pyrolitic self-cleaning cycle.
[0066] The programmable controller also initiates corrective action if unsafe or undesirable conditions are detected. For example, upon detecting excessively high temperatures, high smoke levels or low oxygen levels within the oven, the programmable controller shuts down the burner 44 and the blowers 26 , 27 .
[0067] As mentioned, during cleaning, the interior of the oven 10 is kept under a negative pressure compared to the surrounding atmospheric pressure. In the illustrated embodiment the opening of the vent valve 60 and the operation of the blowers 26 , 27 create the negative pressure in the interior of the oven 10 . As mentioned earlier, when the vent valve 60 is opened and the blowers 26 , 27 are operating, enough circulating hot air escapes through the vent valve 60 to create the negative pressure inside the cooking chamber 16 necessary to force the smoke and soot created during the cleaning cycle through the vent tube 62 . In another embodiment, an inducer blower (not shown) maintains the interior of the oven 10 under a negative pressure during cleaning as compared to the surrounding atmospheric pressure. The inducer blower creates this negative pressure by drawing air from the blower housing 74 . The blowers 26 , 27 actually assist the inducer blower in creating this negative pressure because the discharge flow from the blowers 26 , 27 is impelled directly into the inducer blower. The combined effect is similar to that of a two-stage blower. The discharge flow from the inducer blower is sent to the vent arrangement 58 .
[0068] The inducer blower could also take suction from the interior of the oven 10 during normal baking The entry of the inducer blower opens directly into the blower housing 74 . The inducer blower may be positioned directly in the path of the discharge air flow from each of the blowers 26 , 27 so that the two sets of blowers work in tandem to reduce the pressure in the interior of the oven 10 . Alternatively, the inducer blower may be mounted anywhere in the interior of the oven 10 . The discharge flow of air from the inducer blower is sent to the vent arrangement 58 for disposal.
[0069] Maintaining negative pressure in the interior of the oven 10 during both cooking and self-cleaning enhances energy efficiency and safety. Maintaining negative pressure in the interior of the oven 10 during the cooking and self-cleaning operations insures that little or no heated air escapes to the kitchen. Minimizing heated air loss makes the oven 10 more energy efficient. Any loss or discharge of heated air from the interior of the oven 10 necessitates the combustion of additional heating gas. By directing all exhaust flows from the oven 10 to the vent arrangement 58 and ultimately the vent tube 62 , the loss or discharge of heated air can be better controlled and minimized. Also, the negative pressure system promotes safety because negative pressure retains burning gases in the interior of the oven 10 rather than permitting them to escape into the kitchen. Additionally, maintaining negative pressure in the oven 10 tends to prevent any smoky residue from building up on the exterior of the oven 10 during normal cooking and self-cleaning operations. The exterior surfaces of the oven 10 remain clean longer because they are not subjected to smoke, which commonly escapes from the atmospheric cooking chambers of conventional ovens.
[0070] The blowers 26 , 27 turn at a relatively low speed during a first incineration period of the cleaning cycle. This low speed uniformly distributes heat throughout the interior of the oven 10 while minimizing convective heat loss through the walls of the oven 10 . The first incineration period generally continues for about one hour, although it may be longer or shorter based on factors such as the cleaning temperature and the amount and type of contamination in the oven 10 .
[0071] During a second incineration period, which is generally about one to three hours in duration, the blowers 26 , 27 operate at a relatively higher speed to promote complete incineration of the contamination or debris accumulation. The temperature of the oven 10 is increased to a peak temperature at least once during the second incineration period.
[0072] After the incineration periods, the programmable controller cools the oven, disengages the safety interlocks and arranges the control system for cooking operation. Due to the combination of high temperature and convective air flow in the inventive oven during the self-cleaning cycle, any contamination accumulation that is in the oven is reduced to harmless and sterile ash. This ash may be collected on drip pans provided for that purpose, which can be accessed through the front access door 40 and carried away to disposal. Alternatively, the ash may be collected in a vacuum cleaner system that is built into or independent of the inventive oven.
[0073] It is contemplated that collection of the ash from the lower fingers may be facilitated by constructing the mesh belt 102 of the main conveyor section 30 so that it is close to or touching the perforated plates of the lower fingers 24 . The mesh belt 102 thus pushes or scrapes the ash from the lower fingers 24 for collection by a drip pan or vacuum system. Preferably, the perforations are formed so that the lower fingers 24 present a nonabrasive surface to the mesh belt 102 .
[0074] Although the invention has been described in detail with reference to certain preferred embodiments, variations and modifications exist within the scope and spirit of the invention as described and defined in the following claims. | A conveyor oven having a first mode of operation and a second mode of operation is provided. The conveyor oven generally includes an oven chamber in which food is cooked, a conveyor movable to convey the food through the oven chamber, a burner to generate heat for the oven chamber, at least one blower to circulate air within the oven chamber, and a controller. The burner has a combustion airflow rate, and operates at a first output during the first mode of operation and at a second output that is greater than the first output during the second mode of operation. The blower operates at a first speed during the first mode of operation and at a second speed that is faster than the first speed during the second mode of operation. The controller is responsive to at least one of a burner output and an internal temperature of the oven chamber, and increases the speed of the blower from the first speed during the first mode of operation to the second speed during the second mode of operation responsive to at least one of an increase of the burner output and an increase of the internal temperature of the oven chamber. | 5 |
This is a continuation application of Ser. No. 09/783,387, filed Feb. 15, 2001, now abandoned, which claims priority to Provisional Serial No. 60/198,755, filed Apr. 21, 2000, which claims priority to European Application No. 00103546.8, filed Feb. 18, 2000.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to Raney copper, to a process for the production thereof and to a process for dehydrogenating alcohols.
2. Background Information
It is known to dehydrogenate diethanolamine to yield iminodiacetic acid (U.S. Pat. No. 5,689,000; WO 96/01146; WO 92/06949; published patent application JP 091 55 195; U.S. Pat. No. 5,292,936; U.S. Pat. No. 5,367,112; CA 212 10 20).
SUMMARY OF THE INVENTION
The present invention provides Raney copper which is characterised in that it is doped with at least one metal from the group comprising iron and/or noble metal.
Doping may be achieved both by alloying the doping element with the Raney alloy, which consists of copper and aluminium, and by impregnating the previously prepared Raney copper with the doping element.
The Raney copper according to the invention may contain the doping elements in a quantity of 10 ppm to 5 wt. %. Noble metal doping may amount to 10 to 50000 ppm, preferably 500 to 50000 ppm. The doping metals may be selected from the group comprising iron and palladium, platinum, gold, rhenium, silver, iridium, ruthenium and/or rhodium.
The Raney copper according to the invention may comprise meso- and macropores, but no micropores.
The inital formed alloy can contain more than 50% Cu so that the finished catalyst contains more residual Al than normally found under the same activation conditions.
The initial formed alloy can be heat treated in air temperatures higher than 500° C. activation.
The initial formed alloy can contain more than 50% Cu and heat treated in air temperatures higher than 500° C. before activation.
The average particle size of the Raney copper according to the invention may be 35±30 μm.
The average particle size of the Raney copper according to the invention is of significance during use in oxidation reactions or alcohol dehydrogenation reactions.
On repeated use, known Raney copper forms granules (agglomerates), so deactivating the Raney copper.
The Raney copper according to the invention doped with iron and/or noble metal is not deactivated by unwanted granulation. Advantageously, the Raney copper according to the invention may readily be filtered.
The Raney copper according to the invention exhibits greater activity in the dehydrogenation of ethylene glycol than the Cr/Raney copper according to EP 0 620 209 A1 or U.S. Pat. No. 5,292,936.
The Raney copper according to the invention furthermore advantageously contains no toxic metals, such as chromium for example.
The present invention also provides a process for the production of the Raney copper, which process is characterised in that a copper/aluminium alloy is activated by means of an aqueous sodium hydroxide solution, the catalyst is washed, suspended in water, an iron salt or noble metal salt solution is added to this suspension, the pH value of the solution is adjusted to a value from 4 to 11, the catalyst is separated from the solution and washed.
The present invention also provides a process for the production of the Raney copper, which process is characterised in that the doping metal is alloyed together with copper and aluminium, is then activated by means of aqueous sodium hydroxide solution and the catalyst is washed.
The present invention also provides a process for the catalytic dehydrogenation of alcohols to their corresponding carbonyls and carboxylic acids, which process is characterised in that a Raney copper doped with iron or noble metal is used as the catalyst.
The process according to the invention for the dehydrogenation of alcohols may be used for dehydrogenating glycols and/or aminoalcohols. The catalyst may be used in the form of a suspension for such reactions.
The alcohols which may be dehydrogenated according to the invention may be mono- or polyhydric alcohols. Said alcohols, including polyether glycols, may be aliphatic, cyclic or aromatic compounds which react with a strong base to yield the carboxylate.
It is necessary in this connection that the alcohol and the resultant carboxylate are stable in a strongly basic solution and that the alcohol is at least somewhat soluble in water.
Suitable primary, monohydric alcohols may include:
aliphatic alcohols, which may be branched, linear, cyclic or aromatic alcohols, such as for example benzyl alcohol, wherein these alcohols may be substituted with various groups which are stable in bases.
Suitable aliphatic alcohols may be ethanol, propanol, butanol, pentanol or the like.
According to the invention, glycols may be oxidised or dehydrogenated to yield carboxylic acids. Glycols may, for example, be:
ethylene glycol
propylene glycol
1,3-propanediol
butylene glycol
1,4-butanediol
It is thus possible, for example, to dehydrogenate ethylene is glycol to yield glycolic acid (monocarboxylic acid) and to produce the dicarboxylic acid oxalic acid by subsequent reaction with KOH.
Aminoalcohols may also be dehydrogenated with the doped Raney copper according to the invention to yield the corresponding aminocarboxylic acids. The amino alcohols may have 1 to 50 C atoms.
It is accordingly possible, for example, to dehydrogenate N-methylethanolamine to yield sarcosine; THEEDA (tetrahydroxyethylethylenediamine) to yield the tetrasodium salt of EDTA (ethylenediaminetetraacetate); monoethanolamine to yield glycine; diethanolamine to yield iminodiacetic acid; 3-amino-1-propanol to yield beta-alanine; 2-amino-1-butanol to yield 2-aminobutyric acid.
In one embodiment of the invention, the process according to the invention may be used to dehydrogenate aminoalcohols of the formula
in which R 1 and R 2 each mean hydrogen; hydroxyethyl; —CH 2 CO 2 H; an alkyl group having 1 to 18 C atoms; an aminoalkyl group having 1 to 3 C atoms; a hydroxyalkylaminoalkyl group having 2 to 3 C atoms and phosphonomethyl.
The aminoalcohols which may be used according to the invention are known. If R 1 and R 2 are hydrogen, the aminoalcohol is diethanolamine.
If R 1 and R 2 are hydroxyethyl, the aminoalcohol is triethanolamine. The resultant aminocarboxylic acid salts of these starting aminoalcohols should be the salts of glycine, iminodiacetic acid and nitrilotriacetic acid respectively. Further aminoalcohols comprise N-methylethanolamine, N,N-dimethylethanolamine, N-ethylethanolamine, N-isopropylethanolamine, N-butylethanolamine, N-nonylethanolamine, N-(2-aminoethyl)ethanolamine, N-(3-aminopropyl)ethanolamine, N,N-diethylethanolamine, N,N-dibutylethanolamine, N-methyldiethanolamine, N-ethyldiethanolamine, N-isopropyldiethanolamine, N-butyldiethanolamine, N-ethyl-N-(2-aminoethyl)-ethanolamine, N-methyl-N-(3-aminopropyl)ethanolamine, tetra(2-hydroxyethyl)ethylenediamine and the like.
Further examples of aminocarboxylic acid salts are the salts of N-methylglycine, N,N-dimethylglycine, N-ethylglycine, N-isopropylglycine, N-butylglycine, N-nonylglycine, N-(2-aminoethyl)glycine, N-(3-aminopropyl) glycine, N,N-diethylglycine, N,N-dibutylglycine, N-methyliminodiacetic acid, N-ethyliminodiacetic acid, N-isopropyliminodiacetic acid, N-butyliminodiacetic acid, N-ethyl-N-(2-aminoethyl)glycine, N-methyl-N-(3-aminopropyl)glycine, ethylenediaminetetraacetic acid etc.
R 1 or R 2 may also be a phosphonomethyl group, wherein the starting amino compound may be N-phosphonomethylethanolamine and the resultant amino acid N-phosphonomethylglycine. If, of R 1 or R 2 , one R=phosphonomethyl and the other R=—CH 2 CH 2 OH, the resultant amino acid would be N-phosphonomethyliminodiacetic acid, which may be converted in known manner into N-phosphonomethylglycine. If, of R 1 or R 2 , one R=phosphonomethyl and the other R is an alkyl group, the resultant acid would be N-alkyl-N-phosphonomethylglycine, which may be converted into N-phosphonomethylglycine in accordance with U.S. Pat. No. 5,068,404.
The process according to the invention may be performed at is a temperature of 50 to 250° C., preferably of 80 to 200° C., and at a pressure of 0.1 to 200 bar, preferably at standard pressure to 50 bar.
The pressure is required because the alcohols have an elevated vapour pressure. If the pressure were too low, the alcohol would also be discharged when the hydrogen was discharged.
DETAILED DESCRIPTION OF THE INVENTION
Example 1
Production of the Catalyst According to the Invention
An alloy consisting of 50% Cu/50% Al is activated with an aqueous sodium hydroxide solution. The corresponding catalyst is washed until the sodium aluminate has been completely removed. Hexachloroplatinum is then added to the suspension of the washed catalyst. The pH value is adjusted and stirring of the suspension is continued. The doped catalyst is then washed. The platinum content of the catalyst is 1%. The activity of this catalyst for dehydrogenating ethylene glycol is 299 ml of hydrogen per hour per gram of catalyst (c.f. Example 3).
Example 2
Production of the Catalyst According to the Invention
An alloy consisting of 50% Cu/50% Al is activated with an aqueous sodium hydroxide solution. The corresponding catalyst is washed until the sodium aluminate has been completely removed. Iron (III) chloride is then added to the suspension of the washed catalyst. The pH value is adjusted and stirring of the suspension is continued. The doped catalyst is then washed. The iron content of the catalyst is 3%.
Example 3
Dehydrogenation of ethylene glycol to yield sodium glycolate and sodium oxalate by means of the activated catalyst according to the Example is performed at 108° C. and atmospheric pressure. 70 ml of ethylene glycol are first added to a heterogeneous suspension of 8 grams of catalyst and 70 ml of an aqueous sodium hydroxide solution. The suspension is stirred at 400 rpm. The rate of reaction is measured by means of the quantity of hydrogen evolved between 30 and 90 minutes from the beginning of the reaction. The results are stated as ml of hydrogen per hour per gram of catalyst. The activity of this catalyst for dehydrogenating ethylene glycol is 299 ml of hydrogen per hour per gram of catalyst.
Example 4
Comparative Example
An alloy consisting of 50% Cu/50% Al is activated with an aqueous sodium hydroxide solution. The corresponding catalyst is washed until the sodium aluminate has been completely removed. The activity of this catalyst for dehydrogenating ethylene glycol is 205 ml of hydrogen per hour per gram of catalyst.
Example 5
Comparative Example
A 50% Cu/50% Al alloy is activated with an aqueous sodium hydroxide solution. The corresponding catalyst is washed until the sodium aluminate has been completely removed. Chromium nitrate is added to the suspension of the washed catalyst, the pH value adjusted, stirring of the suspension is continued and the doped catalyst washed once more. The chromium content in the catalyst is 2000 ppm. The activity of this catalyst for dehydrogenating ethylene glycol is 253 ml of hydrogen per hour per gram of catalyst.
Example 6
Comparative Example
A Cu/Al/V alloy is activated with an aqueous sodium hydroxide solution. The corresponding catalyst is washed until the sodium aluminate has been completely removed. The content of V in the catalyst is 1%. The activity of the catalyst for dehydrogenating ethylene glycol is 253 ml of hydrogen per hour per gram of catalyst.
Example 7
Production of Iminodiacetic Acid with Platinum on Raney Copper as Catalyst
The Example illustrates the conversion of diethanolamine (DEA) to yield the sodium salt of iminodiacetic acid (IDA) with Pt-doped Raney copper as catalyst.
The tests are performed in a 2 L Büchi autoclave. The autoclave is equipped with a sparging agitator, which is operated at a standard speed of 500 min-l (sic). The autoclave is equipped with a jacket. The temperature in the autoclave may be adjusted by means of a temperature controlled oil bath.
The following materials are initially introduced into the autoclave:
318.8 g
of diethanolamine (3 mol)
508 g
of aqueous NaOH solution (50 wt. %, 6.3 mol NaOH)
64 g
of catalyst according to the invention: 1% Pt on
Raney copper stored under water
370 g
of H 2 O, ultrasonically degassed
The autoclave is pressurised to 10 bar with nitrogen and adjusted to the reaction temperature (TR=160° C.). Once the reaction has begun, the evolved hydrogen is discharged, with the released quantity being determined by means of a dry gas meter. The reaction is terminated after a period of 5 h and the autoclave cooled. The reaction products are flushed from the autoclave with degassed water, the catalyst filtered out and the dehydrogenation products analysed by ion chromatography.
As table 1 shows, the catalyst used may be recycled repeatedly without appreciable loss of activity.
TABLE 1
Conversion of diethanolamine on Pt-doped Raney copper
Number of batches with catalyst
IDA yield [mol %]
1
94.3
2
92.5
3
98.6
4
96.8
5
95.0
6
94.7
7
90.9
8
91.8
9
93.4
10
95.8
11
97.7
12
93.5
13
95.7
14
92.6
15
90.0
16
n.d.
17
n.d.
18
95.2
[n.d. = not determined]
Example 6
Production of Iminodiacetic Acid with Iron on Raney Copper as Catalyst
The following materials are initially introduced into a 2 L autoclave:
318.8 g
of diethanolamine (3 mol)
508 g
of aqueous NaOH solution (50 wt. %, 6.3 mol NaOH)
64 g
of catalyst according to the invention: 3% Fe on
Raney copper stored under water
370 g
of H 2 O, ultrasonically degassed
The test is performed in a similar manner to Example 5. The yields listed in Table 2 are achieved; no deactivation of the catalyst is observable even after repeated use of the catalyst.
TABLE 2
Conversion of diethanolamine on Fe-doped Raney copper
Number of batches with catalyst
IDA yield [mol %]
1
95.3
2
99.1
3
99.0
4
n.d.
5
n.d.
6
91.9
7
n.d.
8
n.d.
9
n.d.
10
93.7
11
n.d.
12
n.d.
13
n.d.
14
94.0
Example 7
Comparative Example
Production of Iminodiacetic Acid on Undoped Raney Copper
Pure Raney copper (Degussa catalyst BFX 3113W) is used under the conditions of Example 5. The Raney copper exhibits distinct deactivation after only a few batches. (Table 3)
TABLE 3
Conversion of diethanolamine on Raney copper
Number of batches with catalyst
IDA yield [mol %]
1
91.6
2
82.8
3
68.3
4
51.3
Example 8
Production of Glycine with Platinum on Raney Copper as Catalyst
The following materials are initially introduced into the 2 L autoclave:
307 g
of monoethanolamine (5 mol)
420 g
of aqueous NaOH solution (50 wt. %, 5.25 mol NaOH)
64 g
of catalyst according to the invention: 1% Pt on
Raney copper stored under water
400 g
of H 2 O; ultrasonically degassed
The test is performed in a similar manner to Example 5. The yields listed in table 4 are achieved. No deactivation of the catalyst is observable even after repeated use of the catalyst.
TABLE 4
Conversion of monoethanolamine on Pt-doped Raney copper
Number of batches with catalyst
Glycine yield [mol %]
1
98.5
2
97.5
3
n.d.
4
n.d.
5
98.1
Example 9
Production of β-alanine with Platinum on Raney Copper as Catalyst
The following materials are initially introduced into the 2 L autoclave:
380 g
of 3-amino-1-propanol (5 mol)
422 g
of aqueous NaOH solution (50 wt. %, 5.25 mol NaOH)
64 g
of catalyst according to the invention: 1% Pt on
Raney copper stored under water
250 g
of H 2 O; ultrasonically degassed
The test performed in a similar manner to Example 5. The yields listed in Table 5 are achieved. No deactivation of the catalyst is observable even after repeated use of the catalyst.
TABLE 5
Conversion of 3-amino-1-propanol on Pt-doped Raney copper
Number of batches with catalyst
β-Alanine yield [mol %]
1
98.2
2
98.3
3
n.d.
4
n.d.
5
98.3
Example 10
Production of 2-aminobutyric Acid with Platinum on Raney Copper as Catalyst
The following materials are initially introduced into the 2 L autoclave:
460 g
of 2-amino-1-butanol (5 mol)
392 g
of aqueous NaOH solution (50 wt. %, 5.25 mol NaOH)
64 g
of catalyst according to the invention: 1% Pt on
Raney copper stored under water
140 g
of H 2 O; ultrasonically degassed
The test is performed in a similar manner to Example 5. The yields listed in Table 6 are achieved. No deactivation of the catalyst is observable even after repeated use of the catalyst.
TABLE 6
Conversion of 2-amino-1-butanol on Pt-doped Raney
copper
Number of batches with
2-Amino-1-butyric acid yield
catalyst
[mol %]
1
99.2
2
98.1
3
n.d.
4
n.d.
5
98.9
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 shows the advantage of the catalyst according to the invention illustrated by the example of the dehydrogenation or conversion of diethanolamine to yield iminodiacetic acid.
The catalyst according to the invention exhibits a distinctly longer service life than the undoped Raney catalyst. | Raney copper which is doped with at least one metal from the group comprising iron and/or noble metals is used as a catalyst in the dehydrogenation of alcohols. | 1 |
BACKGROUND OF THE INVENTION
1 Field of the Invention
This invention relates generally to drive mechanisms for pedal powered vehicles such as bicycles and tricycles and more particularly to bicycle drive mechanisms of the chainless planetary type.
2. Description of the Prior Art
The most common multiple speed bicycle uses a chain and derailleur system. The chain requires periodic cleaning and oiling to prevent premature chain failure and must be removed from the rear sprocket to change the tire. Chain maintenance is particularly troublesome if the bicycle is ridden extensively on dirt roads and trails. Also, when the rider is bearing down hard on the pedals on a hill, the derailleur usually will not carry the chain to a lower gear. Consequently, with a chain/derailleur system, the cyclist must anticipate the terrain and shift gears before getting on a hill in a gear that is too high, since he may not then be able to shift to a lower gear. Further, all the gears of a conventional ten or twelve speed drive are not efficiently usable because of the angle the chain makes with the sprockets, and shifting is not done in a simple set sequence that is easily mastered. These problems are eliminated with the present invention, as will be seen.
The transmission described in U.S. Pat. No. 2,505,464 by Debuit is a chainless type, located on the axis of the front wheel concentric with the pedal drive shaft, but Debuit's transmission is not planetary, is mounted alongside the wheel hub rather than inside it, is limited in the number of gear ratios it makes available (four plus a direct drive option), and carries the pedal torque through single gear teeth requiring large-tooth gears to prevent early fatigue failure.
SUMMARY OF THE INVENTION
An object of this invention is to provide a compact, durable, low maintenance, multiple speed drive suitable for pedal powered vehicles intended for off-road operation, a particular embodiment being adapted for use on a bicycle camper, with gear ratios low enough to permit transporting the camper payload up steep grades, and high enough to permit conventional bicycle speeds on paved roads.
The three stage planetary driving wheel in accordance with the present invention includes a pedal drive shaft mounted in bearings on the axis of the wheel; a sun gear carrier, a planet gear carrier, and a ring gear all rotatably mounted inside the wheel hub; five sets of different size planet gears with three planet gears in each set mounted on bearings in the planet gear carrier, with each planet gear in constant mesh with a sun gear freely rotating on the sun gear carrier, and in constant mesh with the ring gear; a drive fitting with its axial position adjustable for selectively driving either the ring gear or the planet gear carrier from the pedal drive shaft; means for locking any selected one of the freely rotating sun gears to the sun gear carrier; means for selectively locking either the ring gear or the sun gear carrier to the vehicle frame; and three free-wheel ratchet mechanisms coupling, respectively, the planet gear carrier, the ring gear, and the sun gear carrier with the wheel hub. Five first stage speeds are obtained by driving the ring gear from the pedal drive shaft with the sun gear locked to the vehicle frame and with the planet gear carrier driving the wheel hub through the first free-wheel ratchet mechanism. A direct drive is obtained by driving the planet gear carrier from the pedal drive shaft with both the ring gear and the sun gear carrier free to rotate. Five second stage speeds are obtained by driving the planet gear carrier from the pedal drive shaft with the sun gear locked to the vehicle frame and with the ring gear driving the wheel hub through the second free-wheel ratchet mechanism; and five third stage speeds are obtained by driving the planet gear carrier from tne pedal drive shaft with the ring gear locked to the vehicle frame and the sun gear carrier driving the wheel hub through the third free-wheel ratchet mechanism. Thus, sixteen speeds are available with this particular embodiment of the present invention.
Other aspects and advantages of the present invention will become apparent from the following more detailed description taken in conjunction with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a right side elevation view of the planetary driving wheel;
FIG. 2 is an enlarged cross sectional view taken along the line 2--2 of FIG. 1;
FIG. 3 is an enlarged partial view of the central portion of the wheel hub;
FIG 4 is a partial cross sectional view taken along the line 4--4 of FIG. 2;
FIG. 5 is a partial cross sectional view taken along the line 5--5 of FIG. 2; and
FIG. 6 is a partial cross sectional view taken along the line 6--6 of FIG. 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 2, the planetary driving wheel in accordance with the present invention includes a wheel hub 7; a ring gear 8; ring gear locking teeth 9; a sun gear carrier 10; sun gear carrier locking teeth 11; a planet gear carrier 12; a drive fitting 13; a second stage driving plate 14; a first and third stage driving plate 15; a right side vehicle frame interface fitting 16; a left side vehicle frame interface fitting 17; pedal crank arms 18; and pedal drive shaft 19.
The pedal drive shaft 19 is splined for the transfer of torque from the crank arms 18 to the drive fitting 13. The crank arms 18 and drive shaft 19 are held centered in the vehicle frame interface fittings 16 and 17 by the ball bearings 21. Each of the crank arms 18 is held seated against a splined washer 22 and snap ring 23 by a spanner bolt 20. The inner race of each of the bearings 21 is captive between a shoulder on its respective crank arm 18 and the washer 22, and the outer race is captive between a snap ring and a shoulder on its associated vehicle frame interface fitting 16 or 17.
The ring gear 8 is held centered on the right side vehicle frame interface fitting 16 by the ball bearing 34. The inner race of the bearing 34 is captive between a snap ring and a shoulder on the interface fitting 16, and the outer race is captive between a snap ring and a shoulder on the ring gear 8. The right side driving plate 14, which is installed in the wheel hub 7 with right hand threads so that the driving torque is tightening, is held centered on the ring gear 8 by the ball bearing 36.
The axial position of the drive fitting 13 is adjustable between an inboard position where it drives the planet gear carrier 12, and an outboard position where it drives the ring gear 8. The drive fitting 13 is held in its inboard position by the compression spring 33 which holds the drive fitting seated against a snap ring on the drive shaft 19. Movement to the outboard position is accomplished with the drive fitting positioner 31, which is fabricated in the form of a ball bearing with its inner race captive in the drive fitting 13, and its outer race keyed to axial tracks in the frame interface fitting 16. Axial location of the positioner 31 is controlled by the positioner actuation cable 32 which passes out through two axial holes in the vehicle frame interface fitting 16, wraps around a 90 degree radius in the outboard end of each of the axial holes, and, as seen in FIG. 1, wraps around the pulley 61 whose position is controlled by a two position lever of the vehicle frame.
As best seen in FIG. 6, the ring gear 8 has an internal spline 62 for engaging the drive fitting 13 which matches an identical internal spline in the planet gear carrier 12. As seen in FIGS. 2 and 6, a pair of spring loaded dogs 55 are installed in the ring gear 8 with steel pins 56. The dogs 55 engage machined cogs in the second stage driving plate 14 in a conventional free-wheel ratchet arrangement, and drive the wheel when the ring gear is driven by the selected set of planet gears. When the ring gear is driven by the drive fitting 13, a tooth on the drive fitting 13 engages a radial tab on each of the dogs 55 and holds the dogs out of engagement with the cogs machined in the driving plate 14 so that the wheel can be driven at a rate slower than the ring gear.
As seen in FIG. 2, the sun gear carrier 10 is held centered on the left side vehicle frame interface fitting 17 by the ball bearing 35. The inner race of the bearing 35 is captive between a snap ring and a shoulder on the vehicle frame interface fitting 17, and the outer race is captive between a snap ring and a shoulder on the sun gear carrier 10. The first and third stage driving plate 15, which is installed in the left end of the wheel hub with left hand threads so that the driving torque is tightening, is held centered on the sun gear carrier by the ball bearing 37. As seen in FIGS. 2 and 4, a pair of spring loaded dogs 58 are installed in the driving plate 15 with the steel pins 59 and engage cogs machined in the sun gear carrier 10 in a conventional free-wheel ratchet arrangement so that the sun gear carrier drives the wheel. As also seen in FIGS. 2 and 4, the spring loaded dogs 52 are installed in the first stage drive ring 26 with steel pins 53. The drive ring 26 is attached to the planet gear carrier 12 with three screws 51. The dogs 52 engage cogs machined in the driving plate 15 so that the ring 26 drives the wheel when the sun gear is locked against rotation.
As seen in FIG. 2, a split ring 27 is installed in each of five circumferential grooves in the sun gear carrier 10. An involute sun gear is installed over each of the five split rings with projections on the split rings 27 keying them to the gears, as seen in FIG. 5. The sun gears slide freely on oil-filled porous bronze bushings 25 which maintain the spacing between the gears. The five sun gears have 60, 66, 78, 96, and 126 teeth, respectively, as noted in FIG. 2. Speed selection is achieved through locking a selected one of the five sun gears to the sun gear carrier 10 by positioning a sun gear selector 28 in the plane of the selected gear with a sun gear selector actuation cable 29.
As seen in FIG. 5, four radial projections on the sun gear selector 28 slide in axial slots in the sun gear carrier 10 and key the split ring in the plane of which it is located to the sun gear carrier. The sun gear selector 28 is made up in the form of a ball bearing with the outer race keyed to and rotating with the sun gear carrier, and with the inner race keyed to an integral cylindrical extension of the vehicle frame interface fitting 17. The axial position of the selector 28 is controlled by the sun gear selector return spring 30 and the selector actuation cable 29 which passes out through two diametrically opposed axial holes in the vehicle frame interface fitting 17, wraps around a 90 degree internal radius in the end of each of the axial holes and passes out through two parallel holes orthogonal to the axial holes to wrap 180 degrees around a pulley 61 in an arrangement identical to that shown in FIG. 1 for the drive fitting positioner actuation cable 32.
As shown in FIG. 2, the planet gear carrier 12 is held centered inside an inboard cylindrical extension of the ring gear 8 by a ball bearing 38. The inner race of the bearing 38 is captive between a snap ring and a shoulder on the planet gear carrier 12, and the outer race is captive between a snap ring and a shoulder on the ring gear 8. Five sets of planet gears, with three planet gears in each set, are installed on bearings in the planet gear carrier 12, with each set of planet gears in constant mesh with the 174 tooth ring gear 8 and with one of the five sun gears freely rotating on the sun gear carrier 10. As shown in FIGS. 2 and 5, three 57 tooth planet gears, in mesh with the 60 tooth sun gear, are each mounted on a ball bearing 40 with the inner race of the bearing clamped in the planet gear carrier 12 by a screw 41. Three 54 tooth planet gears, in constant mesh with the 66 tooth sun gear, are mounted on the ball bearing 42 with the inner race of the bearing 42 clamped in the planet gear carrier 12 with a screw 43. Three 48 tooth planet gears, in constant mesh with the 78 tooth sun gear, are each mounted on a ball bearing 44 with a pin 45 in the planet gear carrier 12. Three 39 tooth planet gears, in constant mesh with the 96 tooth sun gear, are each mounted on a ball bearing 46 with the inner race of the bearing clamped in the planet gear carrier 12 with a screw 47. Three 24 tooth planet gears, in constant mesh with the 126 tooth sun gear, are each mounted on an oil-filled porous bronze bushing 50, with the bushing 50 rotating on a polished steel sleeve 49, with the sleeve 49 clamped in the planet gear carrier 12 by the screw 51. The three planet gears in each set are located 120 degrees apart, as shown in FIG. 5, and the planet gears in adjacent sets are located 60 degrees apart. 32 pitch gears are used in the 16-speed example design selected to illustrate the planetary driving wheel in accordance with the present invention.
The exposed outboard end of an integral cylindrical extension on the ring gear 8 has an external tooth form 9, and the exposed outboard end of an integral cylindrical extension on the sun gear carrier 10 has an identical external tooth form 11, which are used for locking the ring gear or the sun gear carrier against rotation through engagement with actuated blocks with mating tooth forms sliding in tracks on the vehicle frame. When the sun gear carrier 10 is locked against rotation and the ring gear 8 is driven from the pedal drive shaft 19 by the drive fitting 13, with the wheel hub driven by the planet gear carrier 12, the first stage gear ratio is given by (0.5N+n)/(N+n) where N is the number of teeth on the selected sun gear and n is the number of teeth on each of the three mating planet gears.
When the sun gear carrier 10 is locked against rotation and the planet gear carrier 12 is driven from the pedal drive shaft 19 by the drive fitting 13 with the ring gear 8 driving the wheel hub, the second stage gear ratio is given by (N+n)/(0.5N+n) where, as before, N is the number of teeth on the selected sun gear, and n is the number of teeth on each of the three mating planet gears.
When the ring gear 8 is locked against rotation and the planet gear carrier 12 is driven from the pedal drive shaft 19 by the drive fitting 13 with the sun gear carrier 10 driving the wheel hub, the third stage gear ratio is given by (N+n)/0.5N. In the table below the number of teeth on the selected sun gear and on each of its mating planet gears is given with the resulting gear ratios for each stage together with the vehicle speed for a pedal speed of 80 rpm and a 27 inch diameter driving wheel. In the example design selected to illustrate the planetary driving wheel in accordance with the present invention, 32 pitch gears are used with 174 teeth and a resultant pitch diameter of 5.4375 inches for the ring gear 8.
______________________________________ SPEED N n RATIO MPH______________________________________first stage one 126 24 .580 3.727 two 96 39 .644 4.138 three 78 48 .690 4.433 four 66 54 .725 4.659 five 60 57 .744 4.781 six direct drive 1.00 6.426second stage seven 60 57 1.345 8.643 eight 66 54 1.379 8.861 nine 78 48 1.448 9.305 ten 96 39 1.552 9.973 eleven 126 24 1.724 11.078third stage twelve 126 24 2.381 15.300 thirteen 96 39 2.813 18.076 fourteen 78 48 3.231 20.762 fifteen 66 54 3.636 23.365 sixteen 60 57 3.900 25.061______________________________________
The gears and resulting gear ratios listed above are presented for illustrative purposes and the present invention should not be considered as limited to them.
While this invention has been described in terms of a preferred embodiment, it is anticipated that persons reading the preceding descriptions and studying the drawings will realize many possible modifications thereof. For example, two or four planet gears could be used in each set instead of three, and they could be rotatably mounted on the planet gear carrier with roller bearings or plain bearings instead of ball bearings. Likewise, the addition of a sun gear and mating set of planet gears would result in a nineteen speed planetary driving wheel, while the deletion of a sun gear and mating set of planet gears would result in a thirteen speed driving wheel.
It is therefore intended that the following appended claims be interpreted as including all such modifications and alterations as fall within the true scope and spirit of the present invention. | A three stage, sixteen-speed, planetary driving wheel, with the pedal drive shaft on the axis of the wheel and vehicle interface fittings on both sides inboard of the pedal crank arms, for mounting in pedal powered vehicles to replace the chain and derailleur system used in conventional multiple speed bicycles. Because the planetary gear arrangement is completely enclosed inside the wheel hub where it is well protected from dirt, and because this driving wheel provides five low range speeds below direct drive, it is well suited for mountain bicycles or for transporting the payload of a bicycle camper up steep grades. | 1 |
BACKGROUND OF THE INVENTION
The present invention relates broadly to a self-contained self-cleaning portable air cleaner and, in particular, to a self-contained air cleaner for industrial applications that is a relatively compact unit that can be easily removed from one work station to another in a manufacturing plant. The unit of the present invention includes an integral compressor in the self-cleaning apparatus so that the unit does not require an external source of compressed air.
The prior art, which includes an air cleaner unit for similar applications manufactured by the assignee of the present invention, comprises portable air cleaner units typically provided with cloth bag filters and means to manually agitate the bags to clean the bag of collected dust. The prior art units thus require significant operator attention and maintenance to periodically clean the filters. Prior art air cleaning apparatus has been developed that is automatic. Such prior art units typically include cylindrical pleated paper filter members. The self-cleaning apparatus is reverse pulse electrically actuated air valves which are disposed to introduce a short pulse or burst of compressed air into the inner axial passageways of the cylindrical pleated paper filter members. Compressed air expands through the pleated paper filtering element dislodging the collected dust therefrom. In the prior art, the reverse pulse air valves commonly are connected to an external air compressor. Thus whenever the air cleaner unit is moved from one location to another, the associated compressor and drive motor associated therewith must also be moved or the unit must be located near an alternative compressed air source. At times it becomes impractical or difficult to locate the unit near a suitable source of compressed air and therefore the prior art units become dependent upon the availability of compressed air.
It is desirable to have a relatively compact air cleaner unit which is self-cleaning and which can operate independently of external compressed air sources. The present invention provides such a unit by incorporating into the unit itself a relatively small capacity compressor. The compressor is driven directly by a power takeoff from the fan or blower which serves to draw air through the air cleaner unit. The compressor is connected to the reverse pulse air valves and electrical control means are provided to regulate the periodic opening and closing of the valves to generate the reverse pulses of clean air. The air cleaner of the present invention incorporates relatively compact housing design that can be easily transported. Operator maintenance of the unit is minimized by the self-cleaning feature and the unit is totally independent of an external compressed air source and therefore truly portable.
SUMMARY OF THE INVENTION
The present invention is a self-contained self-cleaning air cleaner that includes a housing with a first partition mounted within the housing dividing the interior of the housing into a clean air chamber and a filtering chamber. The first partition has an opening therein which provides fluid communication between the filtering and clean air chambers. The housing has a dust-laden air inlet opening into the filtering chamber and a clean air outlet opening into the clean air chamber. Filter means are disposed within the filtering chamber to provide filtered fluid communication between the filtering chamber and the clean air chamber through the opening in the partition. Means are mounted within the housing for drawing air through the housing from the dust-laden inlet to the clean air outlet. Means are provided for periodically and automatically cleaning the filter means of the dust collected thereon. The cleaning means includes a compressor integrally mounted within the housing and a means for driving the compressor directly from the means for drawing air through the housing. A regulated valve means is connected to the compressor and mounted within the housing for periodically and automatically directing a pulse of compressed air from the compressor into the filter means to remove the dust therefrom.
In the preferred embodiment the means for drawing air through the housing includes a fan having a rotating shaft and a compressor having a rotating driven shaft. The means for connecting the rotating shaft of the fan to the driven rotating shaft of the compressor is a flexible shaft. The housing of the air cleaner includes a first housing member with a substantially vertically aligned central elongation axis and which defines the clean air chamber and a second housing member with a substantially horizontally aligned elongation axis defining the filtering chamber. The first partition is disposed within the housing in an oblique plane at an angle with respect to the elongation axes of the first and second housing members.
In one embodiment of the present invention, the filter means includes first and second elongated filter members disposed within the filtering chamber, each having elongation axes generally parallel to the elongation axis of the second housing member. Each of the filter members has an inner axial passageway and an elongated annular filter element providing filtered fluid communication between the filtering chamber and the inner axial passageway. A pair of openings are provided in the first partition and each of the filter members are mounted within the filtering chamber to provide fluid communication through the pair of openings in the partition between the axial passageway and the clean air chamber. The valve means includes first and second electrically actuated valves disposed within the clean air chamber to provide pulses of compressed air from the compressor into the axial passageways of the filter members. Electrical control means are provided for alternately opening the first and second electrically actuated valves in succession to alternately clean the first and second filter members. A compressed air accumulator may be mounted within the housing and connected to the compressor. The accumulator is also connected to the first and second electrically actuated valves and the electrical control means includes a means responsive to the pressure in the accumulator for selectively opening the valves at a predetermined air pressure.
It can be seen that the present invention therefore provides a self-cleaning air cleaner which is independent of external compressed air sources and therefore easily movable from one work location to another as needed. The compressor is driven directly from the fan or blower which is typically electrically powered and which draws air into the cleaner. The filters of the present air cleaner are automatically and periodically cleaned by valve means that are electrically controlled. Thus there is minimum required operator maintenance that consists essentially of removal of dust collected in a dust collection hopper. Manual cleaning of the filters is eliminated, and the maintenance of the filters is limited to periodic inspection and replacement at relatively long intervals of operating time. These and other advantages of the present invention will become more apparent with reference to the accompanying drawings, detailed description of the preferred embodiment, and the claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a view in perspective of the air cleaner of the present invention;
FIG. 2 is a sectional view in side elevation of the air cleaner of FIG. 1;
FIG. 3 is a sectional top plan view of the air cleaner of FIG. 1;
FIG. 4 is an end view in elevation of the air cleaner of FIG. 1 with an access panel removed;
FIG. 5 is an enlarged fragmentary sectional view illustrating the seal between the air cleaner housing and the access panel;
FIG. 6 is an enlarged fragmentary sectional view illustrating the seal between the air cleaner housing and the dust collection hopper;
FIG. 7 is an enlarged view illustrating the connection between the compressor and fan with the compressor shown in section; and
FIG. 8 is a schematic diagram of the electrical control circuit of the air cleaner of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings, wherein like numerals represent like parts throughout the several views, FIG. 1 is a view in perspective showing the portable self-cleaning air cleaner of the present invention designated generally as 10. Air cleaner 10 includes a housing 12 with an upper housing member 14 which is elongated substantially in the horizontal direction and a lower housing member 16 which is elongated substantially in the vertical direction. Removably attached to housing member 14 at the bottom thereof is a dust collection hopper 18. A pair of wheels 20 and 22 are mounted to lower housing 16 proximate dust collection hopper 18 to facilitate relocation of air cleaner 10 to work areas where it may be most needed at a particular time.
Upper housing member 14 includes a top wall 24, side walls 26 and 28, and an open end which is enclosed by removably mounted access panel 30. Housing member 14 also has an inwardly and downwardly sloping bottom wall 32 with an opening at 34 through which collected dust passes into hopper 18. The end of the housing member 14 opposite access panel 30 is mounted to lower housing member 16 as will be described in more detail hereafter. Housing member 16 includes an end wall 36, side walls 38 and 40 and a bottom wall 42 and end wall 44.
As can be seen in more detail in FIG. 2, upper housing member 14 defines a chamber 46 having a substantially horizontally oriented elongation axis. On the other hand, housing member 16 defines a chamber 48 having a substantially vertically oriented elongation axis; the elongation axes of chambers 46 and 48 thereby are disposed substantially perpendicular to each other. Housing members 14 and 16 are joined to each other along an oblique plane, or a plane defined as angularly oriented or disposed with respect to horizontal and vertical axes passing therethrough. Lying in this oblique plane and separating chambers 46 and 48 is a first partition plate 50 mounted within housing 12. As illustrated specifically in FIG. 3, in the preferred embodiment partition plate 50 has a pair of openings 52 and 54 therein to provide fluid communication between chambers 46 and 48. Affixed to partition plate 50 and top wall 24 within chamber 46 and disposed generally in a vertical plane is a second partition plate 56. Partition plate 56 divides chamber 46 into a first chamber portion 58 and a second chamber portion 60. Second partition plate 56 has a pair of large openings 62 and 64 therein which are aligned with openings 52 and 54, respectively. Partition plate 56 also has a plurality of smaller apertures 66 therein and plate 56 functions as a diffuser as will be described in more detail hereafter.
As shown in more detail in FIG. 4, partition plate 56 is affixed to partition plate 50 by a pair of tabs 68 and 70. Portions of partition plate 56 are cut away as indicated at 72 to provide an opening along the bottom edge of plate 56 connecting chamber portions 58 and 60. A pair of annular disc-like filter mounting plates 74 and 76 are mounted to partition plate 56 about openings 62 and 64. A pair of tubular members 78 and 80 are affixed to plates 50 and 56 and provide a fluid passageway between openings 62 and 52 and openings 54 and 64, respectively. Opposite ends of tubular member 78 are affixed about openings 52 and 62 while opposite ends of tubular member 80 are affixed about openings 54 and 64. The fluid passageway defined by tubular members 78 and 80 are sealed from first chamber portion 58. Affixed to tubular members 78 and 80 proximate openings 62 and 64 are a pair of filter mounting yokes 82 and 84 that extend into chamber portion 60. A pair of filters 86 and 88 are mounted about yokes 82 and 84. Filters 86 and 88 may be conventional pleated paper filters that include annular filter elements 90 and 92, each having an inner axial passageway 94 and 96, respectively. Threaded members 98 and 100 extend from the ends of mounting yokes 82 and 84, respectively. Filters 86 and 88 are fastened against mounting plates 74 and 76 by end caps 102 and 104 tightened against annular filter elements 90 and 92 by wing nuts 106 and 108. Filters 86 and 88 are thereby sealed at opposite ends by mountng plates 74 and 76 and end caps 102 and 104. Fluid communication between axial passageways 94 and 96 and second chamber portion 60 is therefore solely through annular filter elements 90 and 92. Tubular members 78 and 80 in conjunction with filters 86 and 88 thereby define a pair of fluid passageways having generally horizontally disposed axes and which provide filtered fluid communication between second chamber portion 60 and chamber 48 through openings 52 and 54.
Access panel 30 is secured by internally threaded knobs 110 and 112 which are received on threaded extension members 90 and 100. FIG. 5 illustrates the preferred manner of providing an airtight seal for access panel 30. Specifically, side walls 26 and 28, top wall 24, and bottom wall 32 are provided with a flange portion, as shown at 114. Access panel 30 has a complementary flange portion 116. A gasket 118 is disposed between complementary flange portions 114 and 116 and may be firmly attached to either. When access panel 30 is tightened by knobs 110 and 112, gasket 118 may be compressed somewhat to provide an airtight seal for second chamber portion 60.
Housing 12 is provided with at least one dust-laden air inlet 120 which opens into first chamber portion 58. In the preferred embodiment, dust-laden air inlet 120 is disposed in a mitered corner 122 of housing 12. It is understood that more than one such dust-laden air inlet may be provided as shown in FIG. 1 or that the positioning of the dust-laden air inlet may be varied as long as the air inlet opens into chamber portion 58.
A fan sheet 122 divides chamber 48 into an upper section 124 and a lower section 126. Affixed to fan sheet 122 is a fan housing 128 in which is mounted a fan or blower designated generally as 130. Fan 130 is mounted vertically within lower section 126. An opening 132 is provided in fan sheet 122 through which air in upper section 124 is drawn into fan housing 128. Fan housing 128 also has an opening at 134 through which air drawn from upper section 124 is blown into lower section 126. Side wall 38 of lower housing member 16 is provided with a louvered panel 136 through which clean air is exhausted from housing 12 Fan 130 may be any conveniently sized unit and is typically electrically powered.
Mounted within upper section 124 of chamber 48 is a filter self-cleaning apparatus designated generally as 138. Self-cleaning apparatus 138 includes a small capacity compressor 140, which will be described in more detail hereafter, mounted to a removable (as shown by the dashed lines in FIG. 2) panel 142 of rear wall 36. Panel 142 can be secured to rear wall 36 by any convenient prior art means or hinged thereto. Compressor 140 is driven by a flexible shaft 144 connected to the rotating shaft of fan or blower unit 130. The compressed air output of compressor 140 is fed through a line 146 to a small capacity accumulator 150 also mounted to panel 142. A pair of reverse flow valves 152 and 154 are mounted on panel 142 and aligned generally with the axes of the axial passageways formed by tubular member 78 and filter 86 and tubular members 80 and filter 88, respectively. Valves 152 and 154 are thus disposed to direct pulses of cleaning air through openings 52 and 54 and thus into axial passageways 94 and 96.
Valves 152 and 154 are connected by lines, one of which is shown at 156, to accumulator 150. In the preferred embodiment, a pressure switch (not shown) is mounted within accumulator 150 and control means are provided to alternately actuate valves 152 and 154 when the pressure within accumulator 150 reaches a predetermined value. Valves 152 and 154 are conventional electrically actuated reverse pulse valves well-known in the prior art.
Hopper 18 may be removably connected to bottom wall 32 by any convenient prior art means. FIG. 6 illustrates a means for providing an airtight seal between hopper 18 and bottom wall 32. Mating flange portions 158 and 160 are mounted to bottom wall 32 proximate opening 34 and hopper 18 proximate the top thereof, respectively. A sealing gasket 162 is disposed between flange portions 158 and 160. It will be understood that gasket 162 may be affixed to either flange portion 158 or flange portion 160. A suitable means for securing hopper 18 to bottom wall 32 can provide compressive force of flange portions 158 and 160 on gasket 162 to ensure an airtight seal. Hopper 18 is disclosed in the preferred embodiment as a rigid dust collection structure, however it is understood that it is contemplated within the spirit and scope of the present invention that hopper 18 may be a wire basket or cage which supports a plastic disposable bag in which dust is collected.
FIGS. 7 and 8 illustrate in more detail small capacity compressor 140, its connection to fan 130, and the electrical control circuit for timing the short burst of cleaning air from valves 152 and 154. In FIG. 7 the hub of the rotating shaft of fan 130 is designated generally as 164. An adapter plate 166 is affixed to hub 164 by convenient means such as welding or screw-type fastening means. Affixed to adapter plate 166 is a conventional swagelok fitting 168. Flexible shaft 144, which may be selected from any convenient prior art design commercially available, is secured to plate 166 by fitting 168. The opposite end of flexible shaft 144 is provided with an internally threaded coupling member 170 which receives a threaded extension 172 of a rotating shaft 174 of small capacity compressor 140. Compressor 140 includes a cylinder head 176 with a compression chamber 178 disposed therein. A piston 180 is mounted for reciprocation within chamber 178 and is connected by a rod and crank mechanism 182 to shaft 174. Cylinder head 176 has a restricted compressed air outlet passageway 184. Air outlet passageway 184 is in fluid communication through a check valve 186 to compressed air outlet 188 to which line 146 to accumulator 150 is connected. Check valve 186 includes a ball 190 biased to close restricted outlet 184 by a spring 192. Rotation of hub 164 of fan 130 is transmitted by flexible shaft 144 to shaft 174. Rotation of shaft 174 causes the reciprocation of piston 180 thereby compressing the air in chamber in 178. Upon each compression stroke of piston 180, ball 190 is lifted from its seat thereby permitting the compressed air to exit to outlet 188 and through line 146 to accumulator 150.
FIG. 8 illustrates schematically the control of reverse pulse air valves 152 and 154. Valves 152 and 154, as previously described are conventional reverse pulse valves and are illustrated in FIG. 8 as solenoid-actuated valves with coils 194 and 196 respectively. A fan motor 198 associated with fan 130 is shown in block diagram form and is connected through a fan motor starter 200 to a source of AC power. Coil 194 and 196 are also connected to the source of AC power through lines 202 and 204 such that valves 152 and 154 cannot be energized unless motor 198 is on. The design of fan motor starter 200 is considered to be within the knowledge of one having ordinary skill in the art. One side of coil 194 is connected to line 202 by line 206. The opposite side of coil 194 is connected by line 208 to a terminal 210a of a stepping relay 210. One side of coil 196 is connected to line 202 by line 212. The opposite side of coil 196 is connected by line 214 to a terminal 210b of stepping relay 210. Stepping relay 210 has a switch arm 216 connected to a common terminal 210c. Terminal 210c is connected to one side of stepping relay coil 218 and by line 220 to a terminal 222a of a pressure switch 222. The opposite side of coil 218 is connected by line 224 to line 202. Pressure switch 222, which may be any conventional switch for detecting the pressure within accumulator 150, includes an off terminal 222b and a common terminal 222c. Terminal 222c provides a return path of power transmission through starter 200 from the source of AC power. Pressure switch 222 has a switch arm 226 connected to terminal 222c and movable between terminals 222a and 222b.
The operation of the present invention will now be described. Air cleaner 10 is started by energizing fan 130. The fan motor is connected to a suitable source of AC power (not shown). Fan 130 drives compressor 140 which begins to pump compressed air into accumulator 150. Fan 130 draws dust-laden air through inlet 120 into first chamber portion 58. Dust and debris entrapped in the air which is larger in size than apertures 66 in partition plate 56 pass through plate 56 at cutouts 72 and into hopper 18 under the effects of gravity and the air flow through chamber 46. Smaller dust particles pass through apertures 66 into second chamber portion 60. The air is drawn through filters 86 and 88 with the dust being deposited on filter elements 90 and 92. The filtered air passes into axial passageways 94 and 96, through tubular members 78 and 80, and through openings 62 and 64 into clean air chamber 48. The cleaned air is drawn through housing 28 and blown from housing 12 through louvered panel 136. As will be described in more detail with respect to the electrical controls, when the pressure in accumulator 150 reaches a predetermined value, one of valves 152 or 154 is opened and a pluse of compressed air stored in accumulator 150 is directed through opening 52 or 54 into axial passageway 94 or 96. The pulse of compressed air tends to expand within tubular members 78 and 80 creating a venturi effect which induces additional reverse air flow. The pulse of cleaning air expands outward through filter elements 90 and 92 from axial passageways 94 and 96 dislodging the accumulated dust thereon. The dust dislodged from filters 86 and 88 is collected in hopper 18. Air continues to be drawn into cleaner 10 during the reverse pulse of clean air and the air flow through housing 46 sweeps across filters 86 and 88 facilitating the removal of the dust from elements 90 and 92 and the collection of the dust in hopper 18. The greater volume of dislodged dust is carried away from the filter into hopper 18 while some of the dust may be redeposited on the filter toward its end proximate cap 102. On the next successive clean air pulse the redeposited dust will again be dislodged from the filter and collected in hopper 18. Partition plate 56 with aperture 66 serves as a diffuser of the air flow from chamber portion 58 into chamber portion 60 to ensure uniform flow through chamber 46.
In the preferred embodiment, valves 152 and 154 are alternately opened. Thus, the successive pulses of reverse flow cleaning air alternate back and forth between filters 86 and 88. Although it is not shown, a vertical separator sheet can be disposed within chamber portion between filters 86 and 88. Such separator sheet would tend to minimize the cross entrapment of dust dislodged from one filter onto the other filter. The separator sheet could also serve the additional function of providing structural support for top wall 24.
In the preferred embodiment, as previously mentioned, self-cleaning apparatus 138 is mounted on a removable panel 142 to facilitate maintenance and repair of apparatus 138. In the preferred embodiment, the inside of louvered panel 136 can also be covered with an open cell foam which acts as a diffuser for the clean air exiting through panel 136. Lower section 126 of chamber 48 may also be lined with a closed cell acoustic foam to reduce sound generated by cleaner 10.
Referring specifically to FIG. 8, the operation of the electrical control of valves 152 and 154 will now be described. With switch arm 226 of pressure switch 222 in the position shown contacting terminal 222b, valves 152 and 154 remain closed and relay 210 is not energized. When pressure switch 222 senses a predetermined pressure within accumulator 150, switch arm 226 is moved to terminal 222a completing a circuit path from line 202 to line 224 through coil 218 of relay 210, through line 220, switch 222 and line 204. With stepping relay 210 thus energized, switch arm 216 would change position from terminal 210a as shown to terminal 210b. Thus, a circuit is also established from line 202 through line 212 to coil 196, through line 214, relay 210 line 220, pressure switch 222 to line 204. Valves 152 and 154 are typically solenoid-type valves and upon introduction of current into coil 196 the valve is opened introducing a pulse of cleaning air from accumulator 150. As can be seen, coil 194 of valve 152 remains unenergized and thus valve 152 remains closed. Upon reduction of pressure in accumulator 150, switch arm 226 of pressure switch 222 returns to terminal 222b breaking the circuit and deenergizing coil 196 and coil 218. Valve 152 is closed and switch arm 226 is positioned in contact with terminal 222b. After the reverse pulse air valve closes the pressure in accumulator 150 begins to build once again. When the pressure reaches the predetermined value, switch 222 is activated and switch arm 226 is moved to contact terminal 222a. Stepping relay 210 is energized and switch arm 216 is thereby disconnected from terminal 210b and connected to terminal 210a. A circuit is thereby completed from line 202 through line 206, coil 194 of valve 152, line 208, stepping relay 201, line 220 and switch 222 to line 204. With coil 194 thus energized, valve 152 is opened and a reverse pulse of cleaning air is introduced into the other of filters 86 and 88. It can be seen that stepping relay 210 provides for the alternating opening of valves 152 and 154 as pressure switch 222 detects the predetermined accumulated pressure within accumulator 150. In the preferred embodiment it is contemplated that accumulator 150 may have a volumne of approximately 0.2 cubic feet. Additionally, a typical actuating pressure may be approximately 90 psi. Compressor 140 may be selected to have a capacity on the order of 0.05 cubic inches. Compressor 140 is operative at all times while fan 130 is running. With an accumulator having 0.2 cubic foot capacity it has been noted that it takes 10 to 12 minutes to fill the accumulator to 90 psi for the initial cleaning air pulse. Thereafter the pulses are generated at approximately 2-minute intervals since the pressure within the accumulator 150 remains relatively high after each pulse with a pulse duration of approximately 15 milliseconds. Pressure switch 222 and stepping relayrelay 210 can be selected from commercially available devices. For example, one suitable stepping relay is a 12-step relay with alternate steps connected in series.
From the above description, it can be seen that the present invention is an improved portable air cleaner which establishes a flow pattern from the dust-laden air inlet through a diffuser partition across dust-collecting filters facilitating reverse pulse dislodged dust movement into a dust collection hopper. The reverse pulses are directed through tubular members which serve as flow inducing venturis during the pulse cleaning operation. Two filter elements may be mounted generally horizontally and side-by-side permitting maximum reduction in overall height and volume. A removable closure panel provides for ease of servicing the filter elements. The reverse pulse apparatus is mounted on a removable panel in a clean air chamber also facilitating maintenance of the unit. The fan is mounted vertically in the clean air chamber lowering the center of gravity of the unit and providing for clean air exhaust into the base of the unit for acoustic control. Housing 12 includes three major subassemblies, upper housing member 14, lower housing member 16 and partition plate 50 to minimize production costs and provide for a modular molded plastic structure. The provision of a small capacity compressor integral with the air cleaner and which is driven by the fan motor eliminates the need for an external source of compressed air thereby making the air cleaner of the present invention truly portable. Although in the preferred embodiment the power takeoff to drive the compressor from the fan is disclosed as a flexible shaft, it is understood that the compressor could be mounted within the housing such that a rigid power takeoff shaft can be utilized to connect the hub of the fan to the shaft of the small capacity compressor. The flexible drive shaft, however, facilitates the mounting of the compressor on the removable back panel of the housing to simplify maintenance of self-cleaning apparatus 138. The compressor and accumulator capacity specifically disclosed above are, it is understood, simply representative of typical suitable values. | A self-contained self-cleaning air cleaner that includes a housing with a first partition mounted within the housing to divide the interior of the housing into a clean air chamber and a filtering chamber. The first partition has an opening which provides fluid communication between the filtering and cleaning chambers. A filtering apparatus is disposed within the filtering chamber to provide filtered fluid communication between the filtering chamber and the clean air chamber through the opening in the partition. A fan or blower is mounted within the housing for drawing air through the housing from a dust-laden air inlet which opens into the filtering chamber to a clean air outlet which opens into the clean air chamber. A small capacity compressor is integrally mounted within the housing and is directly driven by the fan or blower. A reverse air pulse valve is connected to the compressor and disposed within the housing to direct a pulse of clean air into the filter apparatus to dislodge the dust collected thereon. Electrical control circuitry is provided to periodically and automatically open the reverse pulse air valve. The compressor is preferably connected to a compressed air accumulator within the housing and the control circuitry includes a pressure responsive device which monitors the pressure within the accumulator such that the air valve which is also connected to the accumulator is actuated or opened when the pressure within the accumulator reaches a predetermined value. The fan has a rotating shaft and the compressor has a rotating driven shaft. A flexible shaft is provided to connect the rotating shaft of the compressor to the fan rotating shaft to provide the drive for the compressor. | 1 |
CROSS REFERENCE TO RELATED APPLICATION
This is a continuation-in-part of my copending application Ser. No. 242,763, filed Apr. 10, 1972, entitled "Antibacterial Compositions," now abandoned, which is incorporated herein by reference.
DETAILED DESCRIPTION
It is well known that various aromatic ring halogenated compounds possess marked antimicrobial activity. Such substances include ring halogenated salicylanilides, halogenated carbanilides and halogenated thiocarbanilides. It is also known that the utility of these substances and in particular their ease of formulation is in many instances hindered by low solubility in aqueous media. Various solutions to this problem have been found, as for example, the utilization of certain quaternary salts as solubilizing agents; see e.g. British specification Nos. 1,161,671 and 1,161,672. Certain quaternary ammonium compounds themselves have excellent antimicrobial activity, but surprisingly the combination of an aromatic ring halogenated compound and antibacterial quaternary salt produces results which are no more than additive and often less than additive. One possible explanation for this phenomenon is the orientation of the quaternary salt when absorbed as a film on the bacteria. Thus, whereas benzalkonium chloride ordinarily kills bacteria, dried bacteria which are coated with a greasy film can survive many hours of contact with this quaternary salt, presumably because of its absorption being oriented with the harmless hydrocarbon moiety in contact with the bacteria; see Rahm, Proc. Soc. Exptl. Biol. Med., 62, 2-4 (1946 ). Fatty material also seems to protect Staphylococcus aureus against cetyl pyridinium chloride. Cationic soaps are also known to form films which are very resistant to mechanical removal from the skin, with the inner surface of the film showing low bactericidal activity and the outerside of the film strong bactericidal activity. The formation of such films will of course have little effect on combating bacteria if the bacteria remains underneath. See Miller et al, Proc. Soc. Exptl. Biol. Med. 54, 174-6 (1943).
The present invention is based upon the discovery that a combination of two antibacterial agents together with a solubilizing quaternary salt, which itself demonstrates antibacterial activity, results in a degree of antibacterial activity which, in most cases, greatly exceeds the additive effects of the individual components. As will be seen hereafter, this overall effect appears to be largely dependent upon the presence of all three components since the activity of any two of the threee components corresponds to that previously observed, i.e. additive effects. Under the most ideal conditions, the bacteriostatic activity of 3,4',5-tribromo salicylanilide alone against Pseudomonas aeruginosa is 75 ppm. The incorporation of 2% soap reduces this activity to 160 ppm, based on active ingredient. The minimum inhibitory concentration of 2,4,4'-trichloro-2'-hydroxydiphenyl ether alone against Pseudomonas aeruginosa is reported to be greater than 300 ppm. In the presence of a surfactant such as soap, no practical activity is demonstrable. By contrast, the composition of the present invention has anti-bacterial activity even in the presence of a surfactant.
The present invention employs as a first component of the composition an antibacterially effective amount of at least one halogenated salicylanilide, carbanilide or thiocarbanilide having one or two halogen atoms on each phenyl ring and up to one trifluoromethyl on one phenyl ring. Preferably, the halogen atom is chlorine or bromine. These materials are well known to the art and include such species as 3,4',5-tribromo salicylanilide, 3,5-dibromo salicylanilide, 4',5-dibromo salicylanilide, 5-chloro-2',4'-dibromo salicylanilide, 3,4',5-trichloro salicylanilide, 4'-chloro-5-bromo salicylanilide, 2',3,4',5-tetrabromo salicylanilide, 3,4,4'-trichlorocarbanilide and 3-trifluoromethyl-4,4'-dichloro carbanilide. Other suitable compounds of this type are disclosed for example in J. Pharmaceutical Sciences, 50, No. 10,831-837 (1961) and in Arzneimittel Forschung, 4, Heft. 9, 1954. Preferred species of this class as 3,4',5-trichloro salicylanilide, 3,4,4'-trichloro carbanilide, 3-trifluoromethyl-4,4'-dichloro carbanilide and in particular 3,4',5-tribromo salicylanilide and 2',3,4',5-tetrabromo salicylanilide.
The second component of the present composition comprises at least one halogenated 2-hydroxydiphenyl ether or bisphenol.
It is preferred to use a halogenated 2-hydroxydiphenyl ether having one or two halogen atoms on each phenyl ring. Preferably, the halogen atoms are chlorine or bromine. Such halogenated 2-hydroxydiphenyl ethers are well known and described in greater detail in, for example, U.S. Pat. No. 3,506,720. Preferred species of this class include 2,4,4'-trichloro-2'-hydroxydiphenyl ether and 4,4'-dichloro-2'-hydroxydiphenyl ether.
The halogenated bisphenol has the formula ##SPC1##
where X is halogen, preferably chlorine or bromine and where n is 1-4, preferably 1 or 2. These compounds may be prepared by brominating bisphenol under normal conditions, such as atmospheric pressure and a temperature below 100°C, to introduce one or two bromine atoms per phenyl ring. To introduce more than two bromine atoms per phenyl ring, it is necessary to use a Friedel Crafts catalyst, such as aluminum chloride or iron bromide in an anhydrous medium. See, for example, Berichte, 35, p.303, 1902. Typical compounds of this class are 3,3'-dibromo-2,2'-biphenyldiol, 3,3',5,5'-tetrabromo-2,2'-biphenyldiol, 3,3',5,5'-tetrabromo-4,4'-biphenyldiol, octachloro-2,2'-biphenyldiol, 2,2',6,6'-tetrabromo-3,3'-biphenyldiol, and 2,2',6,6'-tetrabromo-4,4'-biphenyldiol.
The quaternary salt of the present invention can be diagrammatically depicted as having the formula (I) below: ##SPC2##
wherein
X is chlorine or bromine;
each of R 1 and R 2 is alkyl of 1 to 3 carbon atoms;
R 3 is alkyl, alkenyl or haloalkyl of 6 to 18 carbon atoms;
A - is a physiological acceptable monovalent anion; each of x, y and z, independent of the other, has a value of from 1 to 10;
the sum of x, y and z is 9 to 15;
m has a value of 0 or 1; and
n has a value of from 1 to 4.
Quaternary salts of this type are disclosed in my copending application Ser. No. 223,308 filed Feb. 3, 1972 entitled "Antibacterial Quaternary Ammonium Salts and Method of Preparing Same," which is incorporated herein by reference. In particular, preferred quaternary salts are those in which X is chloro, A - is the chloride anion, m is 0, n is 1, the sum of x, y and z is approximately 12, R 1 and R 2 are both methyl, and R 3 is a mixture of hydrocarbon chains, 65% dodecyl, 25% tetradecyl and 10% hexadecyl. This quaternary salt is commercially available from Fine Organics, Inc. under the designation HQ8.
The backbone of the novel quaternary salts is formed by a polyol of the formula HOCH 2 --(CHOH) n --CH 2 OH, where n is 1 to 4. Illustrative of this group are glycerol, erythritol and sorbitol. The polyol is condensed with an appropriate 1,2-epoxyalkane of the formula ##SPC3##
where m is as defined above, such as ethylene or propylene oxide. The resulting polyether of the formula: ##SPC4##
where m and x, y and z are as defined above, is next reacted with epichloro or epibromohydrin. Finally, the obtained organic halide of the formula: ##SPC5##
where m, x, y, z and X are as defined above, is condensed with a tertiary amine of the formula NR 1 R 2 R 3 , where R 1 , R 2 and R 3 are as defined above to form the quaternary salt of formula I. Illustrative examples of the tertiary amine are decyl dimethylamine, dodecyl dimethylamine and di-n-propyl octylamine. In connection with the latter reaction, the unexpected observation was made that only the two halides whose positions correspond to the position of the primary alcoholic groups in the starting polyol react with the tertiary amine employed. The following illustrates the sequence of reactions and the chemical operations involved.
A. the intermediate product (II) is prepared from commercially available ethoxylated glycerol as follows:
To 648g (1 mol) of ethoxylated glycerin (containing approximately 12 ethylene groups) and 3 milliliters of the BF 3 -ether complex add 278g of epichlorohydrin at 90°C, then cool to 25°C; add 21 grams of active Al 2 O 3 followed by 600 ml of acetone; filter off Al 2 O 3 and strip acetone.
The immediate product (II) is a viscous liquid. Yield: 877g. Equivalent weight of intermediate (II) is 309 (one-third of mol. wt.).
The reaction may be illustrated by the following equation: ##SPC6##
x + y + z = approximately 12
B. mix 309g (1/3 mol) of (II)
180.5g (2/3 mol) dimethyl dodecylamine and 600 ml n-butanol.
Maintain the reaction mixture at 115°-120°C for 18 hours. Then strip off butanol; a viscous fluid containing the quaternary salt is obtained in nearly quantitative yield. The quaternary salt thus formed has the formula: ##SPC7##
where the sum of x, y and z is approximately 12.
While dodecylamine is used in this illustrative preparation, any C 6 -C 18 amine, or mixture thereof, can be used, such as a commercial trialkylamine containing, for instance, 65% C 12 , 25% C 14 and 10% C 16 alkyl groups. Likewise, any other suitable tertiary base may be used as the quaternizing agent, such as one containing higher alkenyl or halogen-substituted alkyl or alkenyl groups, and in place of the methyl groups, one may be ethyl or propyl or both ethyl and propyl.
The amount of each of the three components in the composition of the present invention is that which will produce in combination with the other ingredients an increased antibacterial effect, as may be readily determined through well known and simple tests such as determination of the minimum inhibitory concentration. In the case of the halogenated salicylanilide, carbanilide or thiocarbanilide, this amount is generally from about 0.05% to about 3% by weight of the composition. The halogenated 2-hydroxydiphenyl ether or bisphenol is in turn present in an amount of from about 0.025% to about 1% of the total weight of the composition. Finally the quaternary salt is generally employed in amounts ranging from about 0.2% to about 4% of the total weight of the composition.
As noted above, the final composition is in the form of an aqueous solution or suspension and thus, in addition to water, the composition may include additional components such as foam builders, cleansing agents, viscosity building agent, hydrotropes, coupling agents, buffering agents, stabilizers and the like. The selection of these adjuvants is determined according to the usual considerations of mutual compatibility, activity, stability and physiological acceptability such as lack of irritation.
Generally the final solution should have a pH of about 7.5 to about 10, preferably 8 to 9, in order to provide good sudsing and cleansing action while maintaining the underlying antibacterial activity. This pH is below that of normal soap and upon dilution with 5 volumes of water, the final pH will generally be from about neutrality to about 9.5. Maintenance of the desired pH can be obtained through the use of buffering agents, as for example borax. Other ingredients which may be added include monoesters of sodium sulfosuccinate, alkanolamine condensate and triethanolamine lauryl sulfates as detergents and foaming agents, xylene sodium sulfonate, a stabilizing agent producing a clear, stable product, propylene glycol, a coupling agent which also imparts stability to the product and the like.
As noted above, the compositions of the present invention find use as surgical scrubs, antiseptic skin cleansers, disinfectants and the like. The compositions not only effect a reduction in bacteria count on the skin but also form a residual antimicrobial mantle. In addition to their antibacterial activity, the compositions have a sudsing and cleansing action.
The following Examples will serve to further typify the nature of this invention without restricting the scope thereof, the scope being defined solely by the appended claims.
EXAMPLE 1
The following compositions are prepared utilizing one-half of the total composition of a basic vehicle preparation composed of the following ingredients: 10% sodium sulfosuccinate half-ester (Emcol 4300, Witco Chemical Corp.); 10% ethoxylated alkanolamine (Emcol 5130 in which the alcohol is a fatty alcohol mixture of C 11 , C 14 , C 15 and C 17 ethoxylated to the extent of 3 mols of ethylene oxide); 2% alkanolamide (Condensate L-90); triethanolamine lauryl sulfate (Richonol T); 5% propylene glycol; 3% borax and 10% xylene sodium sulfonate.
The ingredients of this vehicle are combined with the indicated quantities of antibacterial agents and quaternary salts and the second half of the composition is completed through the addition of water.
TABLE I______________________________________% of Total Composition Halo- HalogenatedCompo- genated Hydroxydi- Quat Vehi-sition Salicyl- phenyl Salt.sup.3 cle Water anilide.sup.1 Ether.sup.2______________________________________A 1 -- -- 50 49B -- -- 2 50 48C -- 0.25 -- 50 49.75D -- -- -- 50 50E 1 -- 2 50 47F -- 0.25 2 50 47.75G 1 0.25 -- 50 48.75H 1 0.25 2 50 46.75______________________________________ .sup.1 = 3,4'-tribromo salicylanilide .sup.2 = 2,4,4'-trichloro-2-hydroxydiphenylether .sup.3 = 1,3-di-[(3-mixed alkyl dimethylammonium-2-hydroxy-propoxy)-polyethoxy]-2-[(3-chloro-2-hydroxyprooxy)-polyethoxy] propane dichloride have a total of about 12 ethoxy groups and in which the "mixed alkyl" is about 65% dodecyl, 25% tetradecyl and 10% hexadecyl (HQ8, Fine Organics, Inc.)?
The antibacterial properties of these compositions can be seen from the following data on the dilutions made in sterile nutrient broth; Letheen broth serving as the subculture media with incubation for 48 hours at 37°C (media growth controls all positive).
TABLE II__________________________________________________________________________Compo- S. aureus E. coli Ps. aeruginosasition MIC KILL MIC KILL MIC KILL__________________________________________________________________________A 1:800 1:800 1:10 1:10: 1:10: <1:5B 1:3200 1:1600 1:5 <1:5 1:10 <1:5C 1:800 1:200 1:10 <1:5 1:10 <1:5D 1:40 1:40 1:5 <1:5 1:5 <1:5E 1:1600 1:1600 1:5 1:5 1:5 <1:5F 1:200 1:50 1:6400 <1:5 1:5 <1:5G 1:1600 1:800 1:12,500 1:12,500 1:10 <1:5H >1:50,000 1:6400 1:50,000 >1:50,000 1:30 1:15__________________________________________________________________________
EXAMPLE 2
The activity of the compositions of the present invention as compared with known antibacterial surgical scrubs may be seen from the following table in which dilutions of the test material were prepared aseptically directly into Difco nutrient broth with the dilutions being incubated at 37°C for 48 hours to determine the MIC and then subcultured into a Letheen broth and incubated for 48 hours to determine kill.
TABLE III__________________________________________________________________________ 3% Composition H HexachloropheneOrganism MIC KILL MIC KILL__________________________________________________________________________S. aureus 1:50,000 1:6400 1:30 1:30 (-) (-) (-) (-)E. coli 1:50,000 1:50,000 1:5 1:5 (-) (-) (-) (+)Ps. aeruginosa 1:15 1:10 1:5 1:5 (-) (-) (-) (+)Salmonella choleraesuis 1:10 1:5 1:5 1:5 (-) (-) (-) (+)__________________________________________________________________________ (-) = no growth (+) = growth
EXAMPLE 3
A composition was prepared according to the following formulation:
Ingredient % Total Composition______________________________________Tribromsalan 2HQ8 42,4,4'-trichloro-2'-hydroxy- diphenyl ether 0.5Emcol 5130 (alkanolamine condensate) 10Emcol 4300 (sodium sulfosuccinate monoester) 40Richonol T (triethanolamine lauryl sulfate) 20Propylene glycol 5Borax 3Xylene sodium sulfonate 5Sodium hydroxide 3.5Water 7Total 100.0______________________________________
The pH of the aforegoing composition is 9.3 and when diluted as a 10% solution, 9.1. The material has an irritation index of 1.5 when tested on skin according to the method of Draize, "Dermal Toxicity," Appraisal of the Safety of Chemicals in Foods, Drugs and Cosmetics, Staff of Division of Pharmacology, FDA, Dept. of HEW, page 47. The material is thus only mildly irritating, less so than commercial hand soap. When tested for eye irritation according to the Draize technique, loc. cit., page 46, a very low score of irritation for unwashed eye and no irritation for washed eye was observed. No damage, including damage to the brain, was observed upon dermal application daily over a period of 30 days to rats.
EXAMPLE 4
The following ingredients are combined to form a skin lotion:
Stearic acid 2.3%Carboxy vinyl polymer Ca 4%Liquid lanolin, oil soluble, dewaxed, liquid fraction of cosmetic grade 5%Triethanolamine 1%Ethyl alcohol 7%Trichlorocarbanilide 0.2%2,4,4'-trichloro-2'-hydroxydiphenyl ether 0.1%HQ8 0.2%
The foregoing ingredients, to which may be added coloring agents and perfumes, are thoroughly blended.
EXAMPLE 5
Following the procedure of Example 1, the following antibacterial compositions are formed:
TABLE IV______________________________________% of Total CompositionCompo- Component Component Quatsition A.sup.1 B.sup.2 Salt.sup.3 Vehicle Water______________________________________I 1 0.25 2 50 46.75J 1 0.25 2 50 46.75______________________________________ .sup.1 Component A for composition I is 2',3,4',5-tetrabromo salicylanide Component A for composition J is 3,4',5-tribromo salicylanide. .sup.2 Component B for composition I is 2,4,4'-trichloro-2-hydroxydiphenylether. Component B for composition J is 3,3',5,5'-tetrabromo-2,2'-biphenyldiol. .sup.3 Same as Quat Salt of Table I. | Aqueous antibacterial compositions for use as surgical scrubs, antiseptic skin cleansers and hand lotions are prepared from a combination of (a) at least one halogenated salicylanilide, carbanilide or thiocarbanilide; (b) at least one halogenated diphenylhydroxy ether or bisphenol; and (c) a quaternary salt derived from an ethoxylated or propoxylated polyol. The compositions are of low toxicity and possess an extremely high order of activity against both Gram-positive and Gram-negative organisms. | 1 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a fluorine-containing elastomer composition and more particularly to a fluorine-containing elastomer compositon capable of producing vulcanized products with good vulcanization properties, especially high tensile strength and elongation.
2. Description of the Prior Art
Owing to useful characteristics at elevated temperatures, such as high heat resistance, high chemical resistance, high oil resistance, high weathering resistance, demands for vulcanized products of fluorine-containing elastomer have been drastically increasing in the form of sealing materials such as gaskets, O-rings, packings etc., hoses, sheets, etc. in the fields of the automobile industry, the oil hydraulic industry, the general machine industry, the aviation industry, etc. In other words, it can be said that the demands for the vulcanized products of fluorine-containing elastomers have become versatile and stringent in addition to a demand for more efficient molding and processing.
Vulcanization of the fluorine-containing elastomer was initially carried out with polyamine-based derivatives such as hexamethylenediamine carbonate and methylenebis-(cyclohexyl)amine carbonate, but these vulcanization systems gave a poor scorching resistance such a poor processing safety and a poor storage stability or the vulcanized products had a poor permanent compression strain. Thereafter, a process for crosslinking the fluorine-containing elastomer with a polyhydroxyaromatic compound in the presence of a vulcanization accelerator and an acid acceptor was proposed as another vulcanization system capable of overcoming the afore-mentioned disadvantages, and has been practically utilized up to now.
The vulcanization accelerators so far proposed for the vulcanization system are quaternary phosphonium salt compounds [Japanese Patent Application Kokai (Laid-open) No. 47-191], quaternary ammonium salt compounds [Japanese Patent Publication No. 52-38072 and Japanese Patent Application Kokai (Laid-open) No. 47-3831], quaternary ammonium salt compounds of 8-alkyl (or 8-aralkyl)-1,8-diazabicyclo[5,4,0]-undec-7-ene [Japanese Patent Publication No. 52-8863] and [Japanese Patent Application Kokai (Laid-open) No. 48-55231], or combinations thereof with such an amount of 1,8-diazabicyclo[5,4,0]-undec-7-ene as substantially not to vulcanize the fluorine-containing elastomer [Japanese Patent Publication No. 57-20333], etc.
However, even with these vulcanization systems, neither tensile strength nor elongation of the vulcanized product reaches the desired satisfactory level yet and also the storage stability of green elastomer compostion is not satisfactory yet.
A vulcanization system containing a vulcanization accelerator of the quaternary ammonium salt compound had a considerable susceptibility to moisture absorption and deliquescence at the storage in addition to the aforementioned disadvantages and thus needed a special consideration for the storing. This not only caused a handling trouble, but also often lowered the vulcanization characteristics and the physical properties of vulcanized products.
The present applicant have been so far made extensive studies on acceleration of the vulcanization rate without deteriorating the scorching resistance and the permanent compression strain of vulcanized products and also on solution of the problems appearing in the so far known vulcanization systems, and previously found that in a vulcanization system using a polyhydroxyaromatic compound as a crosslinking agent in the presence of an acid acceptor, not only good storage stability, processing safety and vulcanization characteristics (vulcanization flowability, vulcanization rate, etc.) as green elastomer composition, but also considerably improved mechanical strength and permanent compression strain of vulcanized product, which had been the problems to be improved in the so far known vulcanization system, could be obtained by using a specific quaternary ammonium salt compound and an N-alkyl-substituted amide compound as vulcanization accelerator components at the same time, or further using such an amount of 1,8-diazabicyclo[5,4,0]-undec-7-ene, 1,5-diazabicyclo[4,3,0]-non-5-ene or 4-dialkylaminopyridine whose an alkyl group has 1 to 4 carbon atoms as to substantially fail to vulcanize the fluorine-containing elastomer together with the said two vulcanization accelerator components, and proposed a vulcanization system based on this finding [Japanese Patent Publication No. 59-46986]. The vulcanization system was found to be effective for improving the dispersibility of the system at the kneading and the shapability at the vulcanization molding.
In the said vulcanization system, a quaternary ammonium salt compound represented by the following general formula [II]: ##STR2## wherein R 1 is an aralkyl group having 7 to 20 carbon atoms, R 2 is a hydrogen atom or a dialkylamino group whose alkyl group has 1 to 4 carbon atoms, and X - is an anion, was used as the said specific ammonium salt compound. A fluorine-containing elastomer compositon containing the quaternary ammonium salt compound and the N-alkyl-substituted amide compound had no fear at all of moisture absorption and diliquescence during the storage. Furthermore, the said fluorine-containing elastomer composition had good storage stability, processing safety, and vulcanization characteristics, and gave a considerably improved shapability at the vulcanization molding, mechanical strength and permanent compression strain to vulcanized products and also had a higher vulcanization rate without deteriorating the scorching resistance.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a novel vulacanization system showing neither moisture absorption nor diliquescence even in a system using the quaternary ammmonium salt compound alone without the N-alkyl-substituted amide compound, but fully showing the preferable characteristics obtained in the afore-mentioned vulcanization systems.
The object can be attained by a fluorine-containing elastomer composition comprising the following components (a) to (d) or (a) to (e). That is, the present fluorine-containing elastomer composition comprises (a) a fluorine-containing elastomer, (b) at least one of an oxide and a hydroxide of divalent metal, (c) a polyhydroxyaromatic compound, and (d) a quaternary ammonium salt compound represented by the following general formula [I]: ##STR3## wherein R is an alkyl group having 1 to 24 carbon atoms, or an aralkyl group having 7 to 20 carbon atoms, R' is a piperidino radical or a pyrrolidinyl radical, and X - is an anion, or further (e) such an amount of 1,8-diazabicyclo[5,4,0]-undec-7-ene or 1,5-diazabicyclo[4,3,0]-non-5-ene as to substantially fail to vulcanize the fluorine-containing elastomer.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Fluorine-containing elastomer to be vulcanized is highly fluorinated copolymers in an elastomeric state, and for example, copolymers of vinylidene fluoride with other fluoroolefins, and more specifically include copolymers of vinylidene fluoride with at least one of hexafluoropropene, pentafluoropropene, trifluoroethylene, trifluorochloroethylene, tetrafluoroethylene, vinyl fluoride, perfluoroacrylate ester, perfluoroalkyl acrylate, perfluoro(methyl vinyl)ether, perfluoro(propyl vinyl)ether, etc., and preferably copolymer of vinylidene fluoride-hexafluoropropene and terpolymer of vinylidene fluoride-tetrafluoroethylene-hexafluoropropene. It is preferable that the copolymer contains about 40 to about 90% by mole of vinylidene fluoride.
As the oxide and the hydroxide as an acid-acceptor in the present invention, generally about 1 to about 40 parts by weight, preferably about 3 to about 15 parts by weight of at least one of oxides and hydroxides of divalent metals such as magnesium, calcium, barium, lead, zinc, etc. is used per 100 parts by weight of the fluorine-containing elastomer in the present invention.
The polyhydroxyaromatic compound for use as a cross-linking agent in the present invention includes 2,2-bis(4-hydroxyphenyl)propane [bisphenol A], 2,2-bis(4-hydroxyphenyl)perfluoropropane [bisphenol AF], hydroquinone, catechol, resorcinol, 4,4'-dihydroxydiphenyl, 4,4'-dihydroxydiphenylmethane, 4,4'-dihydroxydiphenylsulfone, 2,2-bis(4-hydroxyphenyl)butane, etc., preferably bisphenol A, bisphenol AF, hydroquinone, etc. These may be in the form of an alkali metal salt or alkaline earth metal salt. The crosslinking agent is used in an amount of about 0.5 to about 10 parts by weight, preferably about 0.5 to about 6 parts by weight, per 100 parts by weight of the fluorine-containing elastomer. Below about 0.5 parts by weight, the crosslinking density becomes too small, whereas above about 10 parts by weight the crosslinking density becomes too high, with the result that the rubber-like resilience is lost.
The quaternary ammonium salt compound represented by the foregoing formula [I] includes, for example, 1-benzyl-4-piperidinopyridinium chloride, 1-benzyl-4-(1-pyrrolidinyl)pyridinium chloride, 1-benzyl-4-piperidinopyridinium bromide, 1-benzyl-4-piperidinopyridinium stearate, 1-ethyl-4-(1-pyrrolidinyl)pyridinium chloride, etc., and the anionic groups are exemplified above, but may include halide, hydroxide, alkoxide, carboxylate, phenoxide, sulfonate, sulfate, sulfite, carbonate, nitrate, phosphate, thiocyanate, borate, tetraphenylborate, tetrafluoroborate, hexafluorophosphate, hexafluorosilicate, benzoate, etc.
About 0.1 to about 10 parts by weight, preferably about 0.1 to about 2 parts by weight of at least one of the quaternary ammonium salt compounds is used per 100 parts by weight of the fluorine-containing elastomer. Below about 0.1 parts by weight, the crosslinkability will be deteriorated, whereas above 10 parts by weight various characteristics of vulcanized products are adversely influenced to a considerable degree.
At least one of 1,8-diazabicyclo[5,4,0]-undec-7-ene and 1,5-diazabicyclo[4,3,0]-non-5-ene, if contained as an additional component in the composition, has a remarkable effect or the improvement of permanent compression strain of vulcanized products. At least one of these additional components is contained generally in such an amount as to substantially fail to vulcanize the fluorine-containing elastomer, preferably in an amount of not more than about 0.2 parts by weight per 100 parts by weight of the fluorine-containing elastomers, and particularly preferably in a ratio of not more than about 10% by weight thereof to the quaternary ammonium salt compound. Above the upper limit, an adverse effect will appear on the scorching resistance of green elastomer composition, and the crosslinking density of vulcanized product will be too high, resulting in a decrease in elongation.
These components for the vulcanization system can be mixed together and kneaded as such, or diluted with and dispersed in carbon black, silica powder, clay, talc, diatomaceous earth, barium sulfate, etc. or may be used as a master batch dispersion with the fluorine-containing elastomer. Furthermore, so far known filler, reinforcing agent, plasticizer, lubricant, processing additive, pigment, etc. can be added, if desired, to the present composition besides the foregoing components.
Vulcanization is carried out by heating after the said components for the vulcanization system and the said various additives are added to the fluorine-containing elastomer and mixed according to a conventional mixing method, for example, by roll mixing, kneader mixing, Banbury mixing, solution mixing, etc. Generally, primary vulcanization is carried out by heating at a temperature of about 140° to about 200° C. for about 2 to about 120 minutes, and secondary vulcanization is carried out by heating at about 150° to about 250° C. for up to 30 hours.
The present fluorine-containing elastomer composition shows neither moisture absorption nor deliquescence when stored as a green composition, and therefore has not only good storage stability and processing stability, but also good physical properties of vulcanization product, particularly higher tensile strength and elongation than those of the vulcanization systems using 3,5-dimethyl substitute or 4-phenyl substitute of 1-benzylpyridinium chloride requiring no N-alkyl-substituted amide compound at the same time [Japanese Patent Application Kokai (Laid-open) No. 62-89,745 and U.S. Pat. No. 4,734,460].
The present invention will be described in detail below, referring to Examples and Comparative Examples. Examples 1 to 3 and Comparative Examples 1 to 3.
Copolymer obtained by copolymerization of vinylidene fluoride with hexafluoropropene in the presence of ammonium persulfate as a polymerization initiator in an aqueous medium, using acetone as a chain transfer agent [molar ratio of comonomers=78:22 (vinylidene fluoride:hexafluoropropene), solution viscosity η sp/c=0.98 (35° C. in acetone, c=1.0), Mooney viscosity of copolymer ML 1+10 53 (121° C.); fluorine-containing elastomer A] was mixed with the components shown in the following Table 1 according to the composition proportions shown therein through 8-inch mixing rolls to prepare fluorine-containing elastomer composition. The composition formulations are given in parts by weight in Table 1.
TABLE 1______________________________________ Compatative Example ExampleComposition formulation 1 2 3 1 2 3______________________________________Fluorine-containing 100 100 100 100 100 100elastomer AMT carbon black 25 25 25 25 25 25Calcium hydroxide 5 5 5 5 5 5Magnesium oxide 3 3 3 3 3 3Bisphenol AF 2 2 2 2 2 21,8-diazabicyclo- 0.02 0.03[5,4,0]-undec-7-ene1-benzyl-4- 0.4(1-pyrrolidinyl)-pyridinium chloride1-benzyl-4-piperidino- 0.4 0.4pyridinium chloride1-benzylpyridinium 0.35chlorideBenzyltriphenyl- 0.5phosphonium chloride8-benzyl-1,8-diazabi- 0.4cyclo[5,4,0]-undec-7-enium chloride______________________________________
The thus obtained various fluorine-containing elastomer compositions were subjected to determination of moisture absorption and deliquescence of green elastomer composition (sheets of green elastomer compositions, 100×100×2 mm in size, obtained by adding 100 parts by weight of each of valcanization accelerator component to 100 parts by weight of the fluorine-containing elastomer were placed in a low temperature humidistatic and thermostatic chamber made by Hashimoto Seisakusho K. K. Japan, and the surface state of the sheets was inspected after being left at a temperature of 25° C. and a humidity of 70% for 24 hours, and the non-wet state was evaluated as "none", the wet state as "yes", and the water droplet-deposited state as "considerable"); Mooney viscosity and scorching time (time required until the Mooney viscosity takes a minimum value of +5, serving as an index for the storage stability and the processing safety as measured at the temperature of 121° C.) and vulcanization characteristics by means of an oscillating disk rheometer (ODR) made by Toyo Seiki K. K., Japan.
Furthermore, the elastomer compositions were vulcanized by pressing at 180° C. for 5 minutes and then subjected to secondary vulcanization in an oven at 230° C. for 22 hours, and various physical properties of vulcanized products were determined according to JIS K-6301. Permanent compression strain was measured by making O-rings of P-24 through vulcanization under the same conditions as described above and by 25% compression thereof. The results of the determinations are given in the following Table 2.
TABLE 2__________________________________________________________________________ Comparative Example ExampleDeterminations 1 2 3 1 2 3__________________________________________________________________________Moisture absorption and none none none consid- none consid-deliquescence of green erable erableelastomer compositionMooney viscosity 72 72 72 73 72 73ML.sub.1+4 (121° C.) (min.)Scorching time Δ5 28.5 29.0 27.0 20.1 22.4 21.6(121° C.) (min.)Physical properties of vulcanized products (vulcanization at 180°C. for 5 min.by pressing and at 230° C. for 22 hours in an oven)Hardness (JIS A) 75 75 75 75 75 75100% modulus (kg/cm.sup.2) 55 58 60 56 57 59Tensile strength (kg/cm.sup.2) 165 175 179 145 130 137Elongation (%) 240 265 260 195 190 190Permanent compression strain at 175° C.22 hours (%) 11 10 8 10 8 1070 hours (%) 30 27 23 25 24 28__________________________________________________________________________ | A fluorine-containing elastomer composition comprising a fluorine-containing elastomer, at least one of oxide and hydroxide of divalent metal, a polyhydroxyaromatic compound, and a quaternary ammonium salt compound represented by the general formula: ##STR1## wherein R' is a piperidino or a pyrrolidinyl radical, and if desired, further containing 1,8-diazabicyclo-[5,4,0]-undec-7-ene or 1,5-diazabicyclo[4,3,0]-non-5-ene, has good storage stability as green elastomer composition and gives distinguished physical properties to the vulcanized products. | 2 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a speed-compensating apparatus for feeding a plurality of threads to a weaving or knitting machine in which threads are taken up at different speeds, the threads being withdrawn tangentially from spools which are provided with a drive.
2. Description of the Prior Art
Normally the threads fed to such machines are drawn off endwise from the spools, that is, each thread is drawn over a free end of each spool which is not rotated. However in this action the thread is twisted, since in withdrawal over 360°, it is twisted once about its axis. In some machines this twisting is undesired, and the threads must be withdrawn tangentially from the spools, which requires that the spools rotate. If the threads are taken up at different speeds by the machine, either the spools must be driven with correspondingly different speeds, which would necessitate an expensive drive system, or a special speed-adjusting device must be provided.
SUMMARY OF THE INVENTION
The problem of adjusting the thread feeding speed in a weaving or knitting machine is solved in accordance with the invention by passing each thread around the underside of a free travelling compensating pulley which is biased downward by its weight and is movable downward and upward over a specific range of travel. Before each compensating pulley reaches the lower end of its range of travel during downward movement, a first control device produces a signal which indicates the presence at the lower position of the corresponding compensating pulley. In response to the signal from the first control device, the corresponding spool drive clutch is disengaged so that the compensating pulley rises due to continued withdrawal of the thread by the machine. Before each compensating pulley reaches the upper end of the range of travel during upward movement, a second control device produces a signal indicating the presence of the compensating pulley at this point to engage the corresponding spool drive.
The travelling compensating pulley, provided for each thread and movable upwards and downwards over a specific range of travel, produces a thread reservoir which, within the limits of its range of travel, can take up additional thread when the drive speed for the spool exceeds the take-up speed of the machine or can deliver additional thread when the take-up speed of the machine exceeds the drive speed for the spool. When a spool drive clutch is alternately engaged and disengaged in response to the corresponding first and second control devices, the compensating pulley alternately moves downwards and upwards; the speed of movement in each direction varies in accordance with differing thread withdrawal speed of the machine.
The above-explained speed-compensating device finds preferred utilization in warp knitting machines to which transversely extending weft threads are fed in order, for example, to reduce the possibility of transverse stretching of the knitted fabric. These weft threads are laid by a weft carriage moving to and fro over the width of the machine. The weft threads are fed to the weft carriage from above approximately in the middle of the machine width, so that even in the case of substantially constant speed of the weft carriage (apart from the reversing and acceleration at the ends of its travel) a varying thread withdrawal speed results. The thread withdrawal speed here varies periodically from a value close to zero up to a maximum speed.
The second control device can advantageously be formed by a timer actuated by the first control device which is formed by a detector. The duration of the timer is set so that, taking in consideration the mean speed of withdrawal of the working machine, the timer produces a signal; thus the upper end of the range of travel is reached, by the timer in accordance with the mean speed of thread withdrawal.
The capacity of the thread reservoir can be increased by forming the compensating pulley as a multiple pulley around which the thread is passed more than once in a manner similar to the passing of a rope more than once around a multiple pulley tackle block.
For guiding the compensating pulleys, two rails are expediently provided for each pulley which is guided between rails and rests on the rails, the rails being slightly inclined in relation to the vertical in such a way that the weight of the compensating pulleys just presses them against the rails. In this arrangement, practically only the force of gravity acts upon the compensating pulleys during their upward and downward movement, without excessive friction being exerted by the rails upon the compensating pulleys. Consequently the compensating pulleys can adapt themselves immediately to quick variations of speed of withdrawal.
BRIEF DESCRIPTION OF THE DRAWINGS
An example of embodiment of the invention is illustrated in the figures, wherein:
FIG. 1 is side-elevational diagrammatical illustration of an apparatus for feeding threads to a machine in accordance with the invention.
FIG. 2 is a perspective illustration of a double pulley variation for the apparatus of FIG. 1.
FIG. 3 is a diagram of a modified control arrangement for the apparatus of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A thread feeding apparatus with speed-compensation as illustrated in FIG. 1 includes a frame 1 on which a plurality of spindles 14 (only one spindle identified by numeral 14 at spool 8) are rotatably mounted for supporting spools 2-13 pushed onto the respective spindles. A sprocket and clutch mechanism 15 is coupled to each spindle for driving the respective spools. An endless chain 16 is looped around all the clutch sprockets 15 as well as idler sprockets 17, 18 and 19 in a return path. The chain 16 is also looped around one sprocket of a double sprocket 20 which has its other sprocket coupled to a chain 21 driven by a drive system (not shown). Thus on rotation of this drive system when the clutch mechanisms 15 are driving the spindles 14, the spools 2-13 are rotated.
A set of pulleys 23, 24 and 25 is suitably arranged for directing a thread 22 tangentially from each of the spools 2-13 on which the threads 22 are wound. The threads 22 are then fed from the reversing pulleys 25 to the working machine (not shown).
As may be seen from FIG. 1 between the pulleys 24 and 25, each thread 22 is guided around a corresponding compensating pulley 26 which holds the thread 22 under tension by reason of its weight. Each compensating pulley 26 is guided between two rails (only the rear rail 27 is illustrated). The compensating pulley 26 constantly rests on the rails 27 by reason of a slight oblique placing of the rails 27 in relation to the vertical, the weight of the compensating pulley 26 holding the pulley 26 lightly against the rails 27. By reason of the only slightly oblique placing of the rails 27, there is insufficient friction between the compensating pulley 26 and the rails 27 to produce any practical noticeable effect. Thus practically, only the force of gravity is effective in moving the compensating pulley 26, apart from the tension of the thread 22. Consequently the compensating pulley 26 can adapt itself immediately to quickly varying speeds and tensions of the thread 22.
Each speed-compensating device as illustrated furthermore possesses a first control device 28 and a second control device 29. The first devices 28 are for example light detecting control systems in which a light beam 30 is emitted by each device and each device includes means for detecting reflected light. Mirrors 31 for reflecting the light beams 30 back to the devices 28 are arranged within guard plates 32 which also serve to catch the respective compensating pulleys 26 running down inthe case of breakage of the threads 22. Each first control device 28, when the compensating pulley 26 runs through its light beam 30, gives off a signal which through a signal lead represented in dot-and-dash line 33 is conducted to the corresponding clutch mechanism 15 of the spool concerned (illustrated in FIG. 1 only for the spool 2). Each clutch mechanism is such that the clutch mechanism is disengaged between its drive sprocket and spool in response to the signal from the corresponding first control device. Thus each thread 22 is withdrawn from its spool over pulleys 23 and 24 with a very low or zero speed when its clutch mechanism is operated by the signal on line 33 while thread 22 is drawn off over the pulley 25 by tension from the working machine at a speed greater than speed of the thread supplied over pulley 24. Consequently the compensating pulley 26 is pulled up on the rails 27. The control device 28 is positioned so that the light beam 30 is directed to cross the path of movement of the compensating pulley 26 over a relatively great length of its downward movement such that the compensating pulley 26 interrupts the light beam 30 during the entire time required for the first control device 28 to operate the clutch.
The compensating pulley 26 is pulled up in the drawing off of the thread 22 over the pulley 25 by the knitting or weaving machine, until the compensating pulley 26 comes into the region of the second control device 29. This second control device 29 is for example a conventional proximity switch in which an electric or magnetic field is disturbed by the movement of the compensating pulley 26 into proximity thereto so that the control device 29 produces a signal. This signal is fed through the signal lead 34 likewise to the clutch mechanism 15 between the drive sprocket and the spool. Consequently the compensating pulley 26 descends again along the rails 27, whereby the thread reservoir fills again until the compensating pulley 26 comes into the light beam 30 again, whereupon the operation as described above is repeated in response to operation of the first control device 28. It is noted that second control devices 29 are provided individually for all of the compensating pulleys 26 for the corresponding spools 2-13. The relevant signal leads 33 and 34 are assembled in symbolic representation into a bundle 35 of signal leads from the control devices 28 and 29 to the corresponding clutches for spools 2-13.
In this way the thread reservoir provided by the range of travel of each compensating pulley 26 between its first control device 28 and its second control device 29 is constantly filled and emptied again, the compensating pulley 26 running downards for filling and upwards again for emptying.
This style of reservoir filling and emptying has the advantage that no separate expense has to be incurred for the drive systems for the spools 2-13 as regards their speed in adaptation to the speed of thread withdrawal. If in fact it were intended to keep the reservoir constantly in a middle position, it would have to be ensured by means of a special expensive regulating system that the drive systems of the spools 2-13 constantly run exactly at the speed corresponding to the speed of withdrawal by the knitting or weaving machine. Since thread spools are always wound with varying diameters so that the velocity of thread withdrawal fluctuates from spool to spool for a single spool rotational speed, an individual regulated drive system would have to be provided for each spool. In the present device, fluctuation in the velocity of thread withdrawal during the running of the compensating pulley 26 from one extreme position to its other position are readily compensated for by the pulley 26 running upward or downward faster or slower. In addition, the tension of all threads 22 is kept constant in the present apparatus, since the tension is dependent substantially solely upon the weight of the individual compensating pulleys 26. Since these pulleys possess equal weights the tension of all the threads remain constant.
In FIG. 2 there is illustrated a compensating pulley formed as double pulley, consisting of the single pulleys 36 and 37. The two single pulleys 36 and 37 are mounted each freely rotatably on the spindle 38. The thread 22 is here looped around the individual pulleys 36 and 37 as in a tackle block, the following thread course resulting:
The thread 22 runs firstly over the pulley 39 as thead piece 40 to the single pulley 37, then as thread piece 41 to the reversing pulley 42, then as thread piece 43 to the single pulley 36 and finally from the latter as thread piece 44 to the pulley 45 and thence to the weaving or knitting machine.
In the thread reservoir as illustrated in FIG. 2 there is a double storage capacity compared with the individual looping of the compensating pulley 26 of FIG. 1. This can naturally be increased still further by the provision of further single pulleys and correspondingly reversing pulleys, as in a tackle block.
In FIG. 3 another variation of the two control devices is provided. The control device 28 is again illustrated and works in the same manner as described with reference to FIG. 1. The signal emitter 28 through its signal lead 33 not only conrols the clutch mechanism between the drive sprocket and the spool, but furthermore upon producing a signal, also actuates a timer 46 which after a delay produces a signal on its output lead 47. This signal on output 47 is used to cause engagement of the corresponding clutch in the same manner as the output signal of the second control device 29 of FIG. 1. The delay of the timer 46 is set according to the mean speed of withdrawal of the thread 22 by the weaving or knitting machine so that the compensating pulley 26 ascends to a point approaching the end of the range of travel (i.e., to approximately the level of the second control device 29 in FIG. 1). At this moment the timing member 46 produces its signal on its output 47, which then through the signal lead 34 acts in the manner as described with reference to FIG. 1 to engage the clutch of the corresponding spool, whereupon the compensating pulley 26 slides downwards again.
Since many variations, modifications and changes in detail may be made to the above described embodiments, it is intended that all matter described in the foregoing description and shown in the accompanying drawings be interpreted as illustrative and not in a limiting sense. What is claimed is: | Clutches in rotating drives of spools feeding threads to a weaving or knitting machine are disengaged when respective gravity-biased travelling compensating pulleys reach their lower limits and are reengaged when the respective pulleys reach their upper limits. The variable loops of thread formed by the compensating pulleys compensate for different speeds of thread take up by the machine. | 3 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is a continuation-in-part application of U.S. Ser. No. 11/088,287 filed on Mar. 24, 2005 which claimed priority to Provisional Application Ser. No. 60/557,638, filed on Mar. 30, 2004, the disclosures of which are incorporated herein by reference.
FEDERALLY SPONSORED RESEARCH
[0002] The present invention was developed with funds from the Department of Defense. Therefore, the United States Government may have certain rights in the invention.
REFERENCE TO MICROFICHE APPENDIX
[0003] Not applicable.
FIELD OF THE INVENTION
[0004] This invention relates to gas-to-liquid (GTL) technology, and more particularly to GTL processes practiced on a mobile or transportable platform. The invention further relates to a transportable GTL facility which is capable of accessing stranded gas reserves.
BACKGROUND
[0005] Of the estimated 5,500 TCF of natural gas reserves worldwide, nearly one-half is stranded, with over 50% of those reserves being offshore. For our purpose, the term “stranded gas” means natural gas that cannot be economically delivered to market using current gas transportation methods or current commercial GTL processes. Stranded gas includes associated and flared/vented gas, and gas that is re-injected purely for regulatory compliance rather than for reservoir-pressure maintenance. Some of the factors that determine when a pipeline is profitable include resource volume, transport route, pipeline distance, regulatory environment, market size and demand growth. Excess reserves may be considered stranded where a paltry delivery rate is required to avoid oversupply of local markets. Negative economics may also arise from technical complexity or expense associated with recovering and/or gathering the gas.
[0006] One method of producing stranded gas is to process it through a Fischer-Tropsch (FT) gas-to-liquid (GTL) system. GTL is an application of the basic Fischer-Tropsch (FT) process, wherein synthesis gas (or syngas, which is composed primarily of H 2 and CO) is reacted in the presence of a Fischer-Tropsch catalyst to produce heavier hydrocarbons. Possible Fischer-Tropsch end products include kerosene, naphtha, waxes, liquid paraffins and lubes, synthetic diesel, gasoline, and jet fuel. Stranded natural gas may be used as a raw feedstock for GTL operations, thereby monetizing otherwise worthless gas.
SUMMARY OF THE INVENTION
[0007] The GTL barge provided by the invention is designed to develop natural gas assets in the 0.5-5.0 TCF range where there is currently no infrastructure to produce and transport the stranded reserves since the fields are not large enough to economically support an LNG facility. By employing the barge, the owner/operator of the field gets the added benefit of being able to book the reserves. The GTL barge includes a syngas generating section and a Fischer-Tropsch (FT) reaction section. The GTL barge is an inland barge and, therefore, not ocean-going. The GTL barge is designed to be transportable to or near a gas formation by lift ship or other dry haul method. Product upgrading may also be included in the GTL barge, either integrated on the GTL inland barge or located near the GTL barge, such as on a separate barge or on-shore.
DETAILED DESCRIPTION OF THE INVENTION
[0008] The transportable GTL inland barge enables an exploration and production company to produce and thus monetize stranded gas fields. The GTL barge focuses on gas reserves in or near shallow water or onshore gas reserves that are near the coastline or other navigable waterway.
[0009] The GTL barge is ideally suited to process associated rich gas that might otherwise be flared or re-injected. Estimated worldwide flared gas is about 10 billion ft 3 per day. A single GTL barge, for example, may be designed to produce approximately 20,000 barrels per day (bpd) of total liquid products, including approximately 12,000 bpd of GTL products. Assuming the natural gas has about 2 gpm propane and higher carbon number natural gas liquid (“NGL”); the combined NGL and GTL products are about 8700 bpd of clean diesel fuel, 7300 bpd of naphtha, and 4400 bpd of LPG. The mobility and/or transportability of a GTL plant enables the operator to mitigate long-term project and financial risk by having the ability to relocate the barge. The GTL barges may be constructed in shipyards.
[0010] The GTL barge is used where it is within a distance from a gas reserve to-which it would be economically feasible to build a pipeline to transport natural gas feed to the barge. The products from the barge may be either synthetic crude or upgraded products, including for example, transportation fuels.
[0011] Where there are two or more reserves located fairly close to each other, the reserves may be accumulated by pipeline or by compressed natural gas (“CNG”) to supply feedstock to a single GTL barge. Where two or more barges are located in a region, a single syncrude upgrading section may serve such barges and the upgrading section may be located on one of the barges, a separate barge or a separate location. A shuttle barge may be used to carry syncrude to the product upgrading unit.
[0012] In one embodiment of the invention, the GTL barge is constructed on an inland barge. As defined herein, the term “inland barge” means a barge which is transportable by lift ship or other form of barge dry haul and which is not suitable for towing or operation at sea or in any waters having wave action greater than that of Sea State 0 (as defined by Pierson-Moskowitz Sea Spectrum). It should be noted that the Sea State 0 is based upon wind speeds of around three (3) knots. However, as used herein, the term inland barge will include designs which may withstand wind loads of about 120 kilometers per hour or greater. The inland barge, however, may be towed within inland waters, such as rivers, lakes and intercoastal waterways. The inland barge is installed and then operated only in calm water. “Installed” is defined as either freely floating in confining moorings or fixed in a non-floating arrangement. Confining moorings will allow the barge to float on a water body allowing only uniform vertical motion with essentially no lateral or twisting motion. In some embodiments, a barge having jacking legs may be used and installation of the jacking legs installs the barge. As used herein, the term “calm water” means near shore, such as on pylons, beached, or in a natural or man-made inlet which may or may not be dammed and/or drained, or on a fixed platform if off-shore. The term “calm water” may also include inland waterways, such as rivers, lakes, ship channels, bayous, and intercoastal waterways which are protected from substantial natural wave action. Other methods of securing the barge in calm water include use of a flotation jacket surrounding the outer perimeter of the barge, anchoring, or installation of legs under the barge. As used herein, the terms “GTL barge” and “GTL inland barge” are synonymous.
[0013] As the term is defined herein, inland barges are not intended for offshore use unless installed on a fixed platform. Similarly, the term “inland barge” does not include ocean-going vessels which are mobile under their own power. Rather, the inland barge is transported via dry haul lift ship to a location within a commercially practical distance from an appropriate natural gas reserve. Commercially practical distances are those in which a pipeline from the reserve to the barge may be constructed while maintaining the total cost of synthetic crude or hydrocarbon product production within competitive market limits. Such distances vary according to the structure of the intervening terrain as well as other production and market factors, such as then current market prices for the hydrocarbon products to be produced and local labor costs.
[0014] The GTL barge may be split into numerous sections, for example, a natural gas purification section, a natural gas liquid recovery section; a syngas production section; a Fischer-Tropsch Reaction (“FTR”) section; and a product separation/upgrading section. These sections may or may not be modules as equipment from one section may be intermingled with equipment from another section. Alternatively, each section may be substantially self-contained and located substantially separately from the other sections
[0015] For the production of syngas, two basic methods have been employed. The two methods are steam reforming, wherein one or more light hydrocarbons such as methane are reacted with steam over a catalyst to form carbon monoxide and hydrogen, and partial oxidation, wherein one or more light hydrocarbons are combusted or reacted sub-stoichiometrically to produce synthesis gas.
[0016] The basic steam reforming reaction of methane is represented by the following formula:
[0000] CH 4 +H 2 O+Catalyst→CO+3H 2
[0017] The steam reforming reaction is endothermic and a catalyst containing nickel is often utilized. The hydrogen to carbon monoxide ratio of the synthesis gas produced by steam reforming of methane is approximately 3:1.
[0018] Partial oxidation is the non-catalytic, sub-stoichiometric combustion of light hydrocarbons such as methane to produce the synthesis gas. The basic reaction is represented as follows:
[0000] CH 4 +½O 2 →CO+2H 2
[0019] The partial oxidation reaction is typically carried out using high purity oxygen. High purity oxygen can be quite expensive. The hydrogen to carbon monoxide ratio of synthesis gas produced by the partial oxidation of methane is approximately 2:1.
[0020] In some situations these approaches may be combined. A combination of partial oxidation and steam reforming, known as autothermal reforming, wherein air is used as a source of oxygen for the partial oxidation reaction has also been used for producing synthesis gas heretofore. Autothermal reforming is a combination of partial oxidation and steam reforming where the exothermic heat of the partial oxidation supplies the necessary heat for the endothermic steam reforming reaction. The autothermal reforming process can be carried out in a relatively inexpensive refractory lined carbon steel vessel whereby low cost is typically involved.
[0021] The autothermal process generally results in a lower hydrogen to carbon monoxide ratio in the synthesis gas than does steam reforming alone. That is, as stated above, the steam reforming reaction with methane results in a ratio of about 3:1 while the partial oxidation of methane results in a ratio of about 2:1. The optimum, ratio for the hydrocarbon synthesis reaction carried out at low or medium pressure over a cobalt catalyst is 2:1. When the feed to the autothermal reforming process is a mixture of light hydrocarbons such as a natural gas stream, some form of additional control is desired to maintain the ratio of hydrogen to carbon monoxide in the synthesis gas at the optimum ratio of about 2:1.
[0022] In some embodiments the syngas production section of the GTL barge is an Autothermal Reforming unit (“ATR”). The ATR section is any capable of producing a synthesis gas to be utilized in the associated Fischer-Tropsch reaction section. As will be understood in the art, ATR may take different forms but generally is comprised of a vessel having a reforming catalyst (e.g. nickel-containing catalyst) therein which converts the air/steam/natural gas to a synthesis gas. Syngas useful in producing a Fischer-Tropsch product may contain hydrogen, carbon monoxide and nitrogen with H 2 :CO ratios from about 0.8:1 to about 3.0:1. Operating conditions and parameters of an autothermal reactor for producing a syngas useful in the process of the invention are well known to those skilled in the art. Such operating conditions and parameters include but are not limited to those disclosed in U.S. Pat. No. 6,155,039, and U.S. Provisional Patent Application Ser. No. 60/497,177.
[0023] In some embodiments of the invention, an autothermal reforming process is utilized wherein the ATR is fed natural gas and air-derived oxygen. The term “air-derived oxygen” as used herein refers to oxygen obtained from air by means other than a cryogenic air separation plant. For example, air may be passed through a selective membrane through which oxygen is selectively absorbed and/or passed. Such membranes are known in the art, for example, in U.S. Pat. No. 6,406,518. Included in such membranes are those commonly referred to as mixed conductor ceramic membranes, oxygen ion transport membranes, and ionic/mixed conductor membranes.
[0024] The syngas may be optionally preheated before it is delivered to the Fischer-Tropsch reactor. As will be understood in the art, Fischer Tropsch reactors are well known in the art and basically are comprised of a vessel containing an appropriate catalyst (e.g. cobalt-containing catalyst) therein. Fischer-Tropsch catalysts include, for example, cobalt, iron, ruthenium as well as other Group IVA, Group VIII and Group VIIB transition metals or combinations of such metals, to prepare both saturated and unsaturated hydrocarbons. There are several known catalysts which are used in converting a synthesis gas depending on the product desired; e.g., see U.S. Pat. Nos. 6,169,120 and 6,239,184. The Fischer-Tropsch catalyst may include a support, such as a metal-oxide support, including for example, silica, alumina, silica-alumina or titanium oxides. For example, a cobalt (Co) catalyst on transition alumina may be used. The Co concentration on the support may be between about 5 wt % and about 40 wt %. Certain catalyst promoters and stabilizers, which are known in the art, may optionally be used. Stabilizers include Group IIA or Group IIIB metals, while the promoters may include elements from Group IVA, Group VIII or Group VIIB. The Fischer-Tropsch catalyst and reaction conditions may be selected to be optimal for desired reaction products, such as for hydrocarbons of certain chain lengths or number of carbon atoms. Any of the following reactor configurations may be employed for Fischer-Tropsch synthesis: fixed bed, slurry bed reactor, ebullating bed, fluidizing bed, or continuously stirred tank reactor (“CSTR”). The FTR may be operated at a pressure from about 100 psia to about 800 psia and a temperature from about 300° F. to about 600° F. The reactor gas hourly space velocity (“GHSV”) may be from about 1000 hr −1 to about 15000 hr −1 . Operating conditions and parameters of the FTR useful in the process of the invention are well known to those skilled in the art. Such operating conditions and parameters include but are not limited to those disclosed in U.S. Pat. No. 6,172,124.
[0025] Given the safety issues of dealing with pure oxygen, air based systems have a significant advantage with a mobile or transportable system. The use of air instead of pure oxygen for generating synthesis gas in a mobile or transportable process wherein hydrocarbon processing equipment is necessarily located in relatively close proximity to any air or oxygen-handling equipment significantly raises safety, may be less capital-intensive and may reduce the size of the plant and facilities.
[0026] The product separation/upgrading section includes equipment for processing the syncrude products from the FT section to fuel-grade products, namely diesel and naphtha. The upgrading equipment may be installed on the GTL barge or may be located on an adjacent platform, barge or onshore facility. Preferably, products are not stored on the barge but rather transported to a separate location, such as a floating storage offloading unit (FSO) farther out from the shore to hold the product. The FSO may be a reconditioned single hull tanker. Product upgrading equipment may include distillation tower(s) as well as hydroprocessing and hydrocracking reactors.
[0027] The utilities section supplies the utilities for all the processes. An integrated utility facility will provide the most synergy of the various utilities needed for the processes. Some common utilities include, but are not limited to, air, nitrogen, electric power generation, fuel gas system, flare systems, drain systems, boiler feed water supply, steam generation and cooling water. Other utilities include, but are not limited to, hydrogen generation, propane refrigeration, catalyst handling and storage/offloading of multiple products, depending on the GTL barge configuration.
[0028] In a preferred embodiment, the flare is a ground flare and may be located on an auxiliary deck or separate from the GTL barge, such as on shore or on a separate barge or platform.
[0029] Cooling on the GTL barge may come from a combination of a closed-loop cooling water system, high pressure BFW heat recovery, air coolers and direct seawater cooling. Water for the utilities can come from a variety of sources, but most likely would be drawn from the sea near the barge. In a preferred embodiment, the sea water would be drawn from about 250 to about 1750 feet below the surface. Sea water may also be drawn from depths from about 50, 100 or 200 feet below the surface. At this depth, the water is typically about 35 to about 55° F. The sea water preferably has a temperature of ≦55° F., more preferably ≦50° F. In alternate embodiments, the sea water is in tropical climates and the temperature difference of the sea water and the surface of the sea may be as little as about 5.4° F. The amount of deep sea water is dependent upon the temperature of the source water, the discharge temperature, and the heat removal requirements of the GTL process equipment.
[0030] Typically, water used for cooling and discharged to the surface of the sea is limited to about 5.4° F. above the surface temperature, depending on local environmental regulation. For example, deep sea water that starts out at 40° F. can be heated to the local surface temperature plus a margin which is determined by the location. For 90° F. surface water, the discharge temperature could be 95.4° F., resulting in the deep sea water being heated 55.4° F. versus surface water that could only be heated 5.4° F. The increased heat capacity of the deep sea water reduces the amount of water by approximately 1025%. Deep sea water usage results in considerable savings in sea water pumps, sea water piping, heat exchanger surface area, and consumption of power.
[0031] Colder water may also improve contaminate removal from syngas, increase FT catalyst activity, reduced FT catalyst consumption, increase product recovery, reduce compression power requirements, reduce process piping sizes, and reduce FT reactor cooling coils.
[0032] Sea water intake lines would deliver the deep sea water to the barge via a moon pool located within the vessel hull. The moon pool would feed the sea water pumps circulating water to process and utility equipment. Water is forced into the moon pool by the hydraulic head exerted by the surrounding water. In alternate embodiments, any mechanism that is capable of supplying sea water to the cooling water system may be used.
[0033] A GTL plant typically produces and requires large quantities of high grade energy (High Pressure (HP) steam) and produces an excess of lower grade energy (Medium pressure (MP) steam and low-BTU tail gas). By balancing the output from the GTL section with the input needed to produce the syngas, HP steam generated by the GTL section is used as a feed stream to the reformer and can be used to drive compressors and to produce power. All the tail gas is used for process heating and additional HP steam generation. Some additional fuel gas is required for electrical power generation, low-BTU combustors and direct fired heaters.
[0034] A central power plant offers flexibility via possible load shedding of non-essential consumers, load sharing between spare generators and thus higher availability of the main processes. Combinations of steam turbines, gas turbines and generators may be used to provide power. In a preferred embodiment, a steam turbine along with a gas turbine and two diesel engine generators are used to provide power.
[0035] The GTL barge requires hydrogen, which is produced in the reformer of the GTL process. In a preferred embodiment, a separate steam methane reformer (SMR) is proposed to supply hydrogen during startup. In alternate embodiments, a pressure swing absorber (PSA) may also be used alone or in tandem with the SMR.
[0036] While the invention has been described with respect to a limited number of embodiments, the specific features of one embodiment should not be attributed to other embodiments of the invention. No single embodiment is representative of all aspects of the inventions. Moreover, variations and modifications therefrom exist. For example, the GTL barge described herein may comprise other components. The appended claims intend to cover all such variations and modifications as falling within the scope of the invention. | A transportable GTL processing facility constructed on an inland barge is provided. Also provided is a process for producing liquid hydrocarbons from natural gas utilizing a transportable GTL processing facility. The facility and process may be used to access and convert stranded natural gas in an economical fashion into liquid hydrocarbons. Further provided is a transportable GTL processing facility and process for producing liquid hydrocarbons wherein the liquid hydrocarbons are upgraded into transportation fuels and other locally usable materials. Water facilities of the transportable GTL processing facility are supplied from the sea near the barge. | 4 |
INCORPORATION OF RELATED APPLICATION
[0001] This application relates to U.S. patent application Ser. No. 09/851,930 filed on May 10, 2001, the entire contents of which is incorporated herein by its reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates generally to external counterpulsation cardiac assist devices, and more particularly, to external counterpulsation cardiac assist device pressure applicators having an outer shell that resists deformation.
[0004] 2. Prior Art
[0005] In the existing external counterpulsation cardiac assist device (ECPCAD) applicators (hereinafter “applicators”); limb pressure is generated by inflating balloon-like chambers that surround the limb. In addition, to keep the volume of the inflow air in check, the balloon-like chambers are encased in a relatively non-extensible fabric to minimize the bulging out of the applicator assembly.
[0006] The longitudinal and transverse cross-sections of a typical applicator as mounted on a patient thigh are shown in FIGS. 1 and 2, respectively. In these illustrations, the limb 100 is encased in the outer shell 102 . The space between the limb surface and the outer shell 102 is filled with a balloon 101 . Such applicator designs with the outer shell 102 consisting of relatively non-extensible fabric type of material are currently in common use. The outer shell 102 of the applicator and its underlying balloon 101 are generally made wider than usually necessary, and while applying the applicator to the limb, it is overlaid to tightly cover the limb surface and is held in place by an extended VELCRO strap (not shown) or some other similar means.
[0007] The applicator is used by laying the patient on a bed, “wrapping” the applicator around the limbs, usually the legs, the thighs, arms, buttock, etc., and affixing the outer shell 102 by VELCRO or other similar means so that the assembly stays tightly over the limbs. Part of the limb such as the ankles, knees, feet, elbows, chest area, neck and the head are not covered since due to the absence of a considerable amount of muscle mass, no significant amount of blood can be displaced by the external pressure.
[0008] The amount of fluid (i.e., gas or liquid) that is required to operate each applicator is dependent on at least several factors.
[0009] Firstly, the amount of fluid that is required to operate each applicator is dependent on the initial volume (space) between the lining and the balloon and the balloon and the limb (if any) that has to be occupied by the expanding balloon. The effects of this factor is usually countered by attempting to wrap the applicator as closely to the limb surface as possible and leaving as little as possible space (volume or void space) to be filled by the balloon during the pressure application process. This precludes so-called rigid outer shells of various forms that have a fixed inner volume and are to be used on different patients with different limb geometry even though it may be attempted to fill at least part of the gap between the patients limb and such rigid outer shells using variously shaped and various material inserts. The process of filling such gaps is extremely cumbersome and cannot fill all the existing gaps since it is almost impossible to construct the required three-dimensionally shaped inserts, particularly in the presence of highly flexible balloons that are located between the “rigid” outer shell and the limb.
[0010] The amount of fluid that is required to operate each applicator is also dependent on the amount of reduction in the volume of the segment of the limb that is enclosed by the applicator due to the applied pressure by the balloon and the level of limb surface pressure that has to be reached. These factors correspond to the desired and useful action of the applicator, which results in the blood pumping action of the device. The required airflow cannot therefore be reduced without reducing the volume of the blood that is displaced, thereby reducing the effectiveness of the applicator.
[0011] The amount of fluid that is required to operate each applicator is further dependent on the amount of increase in the applicator volume due to the expansion, bulging and change in the cross-sectional shape of its relatively non-extensible outer shell. This factor is indicative of the relative ease with which the outer shell of the applicator can expand and deform to allow its total internal volume (within which the encased segment of the limb is located) to increase with increased balloon generated internal pressure. This increase in the enclosed volume does not serve any purpose as far as the operation and performance of the applicator is concerned, and greatly reduces the efficiency of the applicator operation and it is the main source of increased demand on the air inflow to achieve the desired level of (limb) surface pressure during each cycle of its operation.
[0012] The amount of fluid that is required to operate each applicator is still further dependent on the volume of the soft tissue that may be pushed out of the sides of the applicator enclosure as the balloon is pressurized and pressure is applied to the limb segment. This factor also reduces the efficiency of the applicator by allowing some soft tissue mass to be pushed out of the enclosed volume, thereby reducing the volume of the displaced blood. In addition, the required volume of the air inflow to achieve the desired level of surface pressure is increased.
[0013] Lastly, the amount of fluid that is required to operate each applicator is still yet further dependent on the sliding of the shell down the limb towards a thinner section of the limb, thereby increasing the volume that has to be occupied by the expanding balloon. This factor greatly reduces the efficiency of the applicator by requiring a larger amount of air inflow to achieve the desired surface limb pressure.
[0014] Ideally, if the outer shell of the applicator is constructed to be rigid and to closely follow the contour of the enclosing limb surface (while allowing room for the pressure producing balloon), and prevented from shifting to the thinner side of the limb, the aforementioned increase in the internal volume of the applicator is almost totally eliminated. However, such rigid outer shells have to be constructed for each specific limb section of each individual to closely match their limb surface contour. Such relatively rigid applicator outer shells may be custom made using, for example various molding and rapid prototyping techniques known in the art, but with relatively high expense and by requiring an extended amount of time to produce the applicators for each individual patient.
SUMMARY OF THE INVENTION
[0015] Therefore it is an object of the present invention to provide a device and method for significantly reducing the aforementioned tendency of the outer shell of the applicator to expand and/or deform and thereby increase their internal volume as the internal balloon is pressurized.
[0016] Another objective of the present invention is to provide a device and method for minimizing the amount of soft tissue that is pushed out of the enclosed volume of the applicator.
[0017] Another objective of the present invention is to provide a device and method for minimizing the sliding of the applicator along the limb towards the thinner segments.
[0018] Accordingly, an applicator for applying an external counterpulsation to a body portion is provided. The applicator comprising: an outer shell for covering the body portion, the outer shell having a length in a longitudinal direction and a circumference in a circumferential direction; a balloon disposed in the outer shell, pressurization of which applies an external pressure to the body portion; and at least one anti-deformation member for reducing an amount of deformation of the outer shell caused by the pressurization of the balloon.
[0019] In a first preferred implementation, the at least one anti-deformation member preferably comprises a plurality of beam members disposed on an outer surface of the outer shell in the longitudinal direction. Preferably, the plurality of beam members are equally spaced along the circumference of the outer shell and at least one of the plurality of beam members has an I-beam cross-sectional shape.
[0020] Preferably, the plurality of beam members are disposed on the outer shell by threads that engage a portion of the beam members and a corresponding portion of the outer shell. Alternatively, the outer shell further comprises a pocket having an opening extending in the longitudinal direction for each of the plurality of beam members, wherein each of the plurality of beam members are disposed in a corresponding pocket. Preferably, the pockets are disposed on an outer surface of the outer shell. The pockets are preferably fastened to the outer shell by threads that engage a portion of the pockets and a corresponding portion of the outer shell.
[0021] At least one of the plurality of beam members preferably further comprises two or more beam segments, each of which are separated by a hinged joint to allow the beam member and outer shell to conform to a shape of the body portion in the longitudinal direction. Preferably, the hinged joint is a ball joint for allowing rotation of the beam segments in at least two directions. Alternatively, the hinged joint is a pinned joint for allowing rotation of the beam segments in a direction parallel to the longitudinal direction. The outer shell has a first and second end separated in the longitudinal direction by the length, wherein at least one of the plurality of beam members is preferably attached to the outer shell at each of the first and second ends.
[0022] In another preferred implementation, the applicator further comprises at least one transverse element disposed between at least two adjacent beam members of the plurality of beam members. Preferably, the at least one transverse element extends in the circumferential direction of the outer shell. The at least one transverse element can extend only in the circumferential direction or alternatively, the at least one transverse element comprises first and second transverse elements, the first and second transverse elements crisscrossing in the circumferential direction.
[0023] In another alternative, the at least one transverse element comprises a solid plate having a length substantially equivalent to the length of the outer shell. In another alternative, the at least one transverse element extends concavely in the circumferential direction.
[0024] In yet another alternative, the at least one anti-deformation member comprises constructing at least a portion of the outer shell with a plurality of truss elements which extend in the longitudinal direction. Preferably, each of the plurality of truss elements comprises a triangular truss element. The triangular truss elements preferably have a top and two angled sides, the top extends in the circumferential direction and the two angled sides extend in the longitudinal direction. The anti-deformation member preferably further comprises an outer sheet disposed on the tops of each of the triangular truss elements. Preferably the triangular truss elements and sheet member further comprise Velcro disposed between the tops and the outer sheet for connecting the outer sheet to the tops. Preferably, the plurality of truss elements are formed on a bottom sheet, the bottom sheet having a joint formed between adjacent truss elements. At least one of the joints is preferably a living joint formed in the bottom sheet.
[0025] In yet another preferred implementation, the applicator further comprises means for preventing tissue from bulging out from the first and second ends of the outer shell due to the pressurization of the balloon. Preferably, the means for preventing tissue from bulging out from the first and second ends comprises a collar disposed around the body portion adjacent each of the first and second ends. The collar preferably comprises a thin flexible material wrapped around the body portion adjacent each of the first and second ends to a desired height.
[0026] In still yet another preferred implementation the applicator further comprises means for preventing movement of the outer shell in the longitudinal direction. Preferably, the means for preventing movement of the outer shell in the longitudinal direction comprises a flexible material wrapped around both the first and second ends of the outer shell and the corresponding body portion adjacent the first and second ends. Where the applicator further comprises the means for preventing movement of the outer shell in the longitudinal direction, the means for preventing movement of the outer shell in the longitudinal direction preferably comprises a flexible material wrapped around both the first and second ends of the outer shell and the corresponding collars.
[0027] Also provided is a method for applying an external counterpulsation to a body portion. The method comprising: covering the body portion with an outer shell, the outer shell having a length in a longitudinal direction and a circumference in a circumferential direction; disposing a balloon in the outer shell; pressurizing the balloon to apply an external pressure to the body portion; and disposing at least one anti-deformation member in or on the outer shell for reducing an amount of deformation of the outer shell caused by the pressurization of the balloon.
BRIEF DESCRIPTION OF THE DRAWINGS
[0028] These and other features, aspects, and advantages of the apparatus and methods of the present invention will become better understood with regard to the following description, appended claims, and accompanying drawings where:
[0029] [0029]FIG. 1 illustrates a longitudinal sectional view of an applicator of the prior art shown disposed about a patient's limb.
[0030] [0030]FIG. 2 illustrates a radial sectional view of the applicator of FIG. 1 as taken along line 2 - 2 in FIG. 1.
[0031] [0031]FIG. 3 illustrates the applicator of FIG. 2 in which the shell is deformed in a longitudinal direction.
[0032] [0032]FIG. 4 illustrates a radial sectional view of a first variation of a preferred implementation of an applicator of the present invention.
[0033] [0033]FIG. 5 illustrates a first variation of a partial enlarged view of the applicator of FIG. 4.
[0034] [0034]FIG. 6 illustrates a second variation of a partial enlarged view of the applicator of FIG. 4.
[0035] [0035]FIG. 7 illustrates a longitudinal view of a first variation of the beam members of FIG. 4.
[0036] [0036]FIG. 8 illustrates a longitudinal view of a second variation of the beam members of FIG. 4.
[0037] [0037]FIG. 9 illustrates a partial radial sectional view of the applicator of FIG. 4 that has a portion of radial bulging.
[0038] [0038]FIG. 10 illustrates transverse elements connected between two beam members.
[0039] [0039]FIG. 11 illustrates a partial radial view of the applicator of FIG. 4 that has a transverse element disposed between two beam members.
[0040] [0040]FIG. 12 illustrates a truss structure disposed around an applicator and limb.
[0041] [0041]FIG. 13 illustrates a partial view of a sheet member used to fabricate the truss structure of FIG. 12.
[0042] [0042]FIG. 14 illustrates a partial view of the truss structure of FIG. 12 having an outer layer formed thereon.
[0043] [0043]FIG. 15 illustrates a sectional view of an applicator in a longitudinal direction showing preferred implementations of both a means for preventing tissue from bulging out of the first and second ends and means for preventing a movement of the applicator in the longitudinal direction.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0044] Although this invention is applicable to numerous and various types of applicators and fluids for use therein, it has been found particularly useful in the environment of applicators for use on limbs that operate with air. Therefore, without limiting the applicability of the invention to applicators for limbs that operate with air, the invention will be described in such environment.
[0045] As used herein, the term “longitudinal” refers to the direction along a limb's length, while the term “radial” refers to the direction perpendicular to the longitudinal direction. Further, “circumference” and “circumferential direction” refer to the length and direction, respectively, around the applicator as shown in cross-section. Although, the applicators are shown as having a circular or near-circular cross-section in the Figures, they are shown as such by way of example only and not to limit the scope or spirit of the present invention. Further, the terms “circumference” and “circumferential direction” are not to be interpreted to only cover such circular or near-circular configurations.
[0046] In general, there are at least four modes of deformation that contribute to the aforementioned increase in the internal volume of the outer shell as the balloon is pressurized. Each of these four modes of deformation will now be fully explained and preferred implementations of devices and methods for minimizing them are described with regard to the Figures. To this end, simplified models of the applicator's outer shell structure are utilized to describe each mode of deformation and the devices and methods of countering them. However, it is appreciated by those of ordinary skill in the art, that the devices and methods described herein can be utilized with applicator's of varying complexity and configuration without departing from the scope or spirit of the present invention.
[0047] Mode 1: Longitudinal Deformation of the Outer Shell:
[0048] Referring now to FIG. 3, the first mode of deformation is illustrated therein. This mode of deformation is the result of the outer shell 102 bulging out in the longitudinal plane as the balloon 101 is pressurized. In this mode, the outer shell 102 is deformed outward along a length “L” in a longitudinal direction (A) in a mode similar to bending in beams that are under a distributed bending pressure (force). This mode of deformation occurs even if the outer shell 102 fabric is relatively non-extensible and cannot therefore readily expand in the radial and longitudinal directions since the outer shell 102 is relatively free to contract longitudinally due to the fact that first and second sides 103 , 104 are not held a relatively fixed distance apart.
[0049] Referring now to FIG. 4 therein is shown a preferred implementation of an applicator that prevents or reduces the longitudinal bulging of the shell shown in FIG. 3. The outer shell 201 has beam members 200 with appropriate bending stiffness that are placed longitudinally and held against an outer shell 201 . The beam members are attached or otherwise firmly held against the non-extensible fabric of the outer shell 201 and disposed along the circumferential direction (C), preferably equally spaced about the circumference of the outer shell 201 . In general, any number of such beam members 200 may be employed. At the limit, the outer shell 201 may be made entirely of such beam members 200 that are placed very close to each other or even side by side and held together by relatively non-extensible fabric or other material. However, it is preferred that a certain amount of spacing between the beam members 200 be provided to reduce the weight of the outer shell 201 and make it easier to apply to the limb segment. The beam members 200 are preferred to be held together by the aforementioned relatively non-extensible fabric of the outer shell 201 to prevent the radial expansion of the shell 201 under the balloon pressure. Such an arrangement of the longitudinally positioned beam members around the periphery of the thigh is shown in the cross-sectional view of FIG. 4.
[0050] In FIG. 4, I-beam type beam members 200 are shown. Such sections are preferred since they provide high bending stiffness with low cross-sectional area; thereby low weight per unit length of the beam members 200 for a required level of bending stiffness. However, it will be appreciated by those of ordinary skill in the art that due to other considerations, such as manufacturing and assembly considerations, beam members 200 with other cross-sectional areas may also be used as long as they are sized to provide the required bending stiffness.
[0051] In FIG. 4., the beam members 200 are shown arranged around the limb segment 100 , which is covered by the balloon 101 . The beam members 200 are fixed to the non-extensible material of the outer shell 201 , preferably a fabric or similar non-extensible material with bending flexibility to prevent outward radial expansion of the beam members 200 and outer shell 201 assembly. The beam members 200 and the non-extensible fabric like material of the outer shell 201 may be assembled in a variety of ways such as by permanently attaching the beam members 200 to the relatively non-extensible fabric outer shell 201 , for instance by using similar fabric threads 203 as shown in FIG. 5. Alternatively, the beam members 200 can be firmly encased in pockets 204 that are provided in the relatively non-extensible fabric shell 201 , for instance as shown in FIG. 6. The pockets 204 can be integrally formed with the shell 201 or attached thereto, such as by threads 205 .
[0052] The device and method illustrated in FIG. 6 are preferred since it is easier to manufacture, assemble and apply to the limb segment. In addition, the pockets 204 can be filled with the beam members 200 as needed to prevent the bulging out of the applicator under balloon pressure.
[0053] Referring now to FIGS. 7 and 8, there are shown first and second variations of the beam members, referred to by reference numerals 200 a and 200 b , respectively. The beam members 200 a and 200 b illustrated in FIGS. 7 and 8 are shown in the longitudinal direction (along the length of the applicator). FIGS. 7 and 8 illustrate the stiffening beam members 200 , particularly when encased in the pockets 204 , constructed as beam segments 300 , 400 that are hinged together, preferably with spherical (ball) joints 301 or simple hinged (pin) joints 401 with their axes of rotation perpendicular to the long axis of the beam segments 400 and directed in the transverse direction in the assembled applicator. In FIG. 7, three beam segments 300 with their long axes 302 are shown connected with spherical joints 301 . In FIG. 8, three beam segments 400 with their long axes 402 are shown connected with the simple hinge joints 401 that allow relative rotation of the beam segments about axes 403 which are perpendicular to the axes 402 . Such beam members 200 a , 200 b allow the outer shell 201 to be readily contoured to the outer surface geometry of the limb segment, but would still prevent the aforementioned bulging of the outer shell 201 since the total length of the beam members 200 a , 200 b cannot be reduced. In both cases, the ends of the segmented beam members 200 a , 200 b are firmly attached to the first and second ends 103 and 104 of the outer shell 201 .
[0054] Mode 2: Radial Expansion of the Outer Shell:
[0055] This mode of deformation refers to the radial expansion of the outer shell 201 due to its elastic behavior as the inner balloon 101 is pressurized. As a result, even if longitudinal bulging of the outer shell 201 is prevented by the aforementioned beam members 200 , the volume enclosed by the outer shell 201 is increased, thereby increasing the amount of fluid that has to be pumped into the balloon(s) 101 to achieve the desired level of limb surface pressure.
[0056] This mode of deformation can be prevented by using a relatively non-extensible fabric or the like to construct the outer shell 201 as described for the previous mode of deformation. Alternatively, this mode of deformation can be prevented by preventing radial expansion of the outer shell 201 using one or more straps (not shown) of relatively non-extensible material that are wrapped over the outer shell 201 and locked in place by VELCRO or other similar means. The straps may be of various widths. One may even use a single “strap” that is the length of the outer shell 201 . On the other hand, a string or band (not shown) of relatively non-extensible material may be also be used to wrap around the outer shell 201 and secured in place.
[0057] The latter is generally preferable since an outer shell 201 is generally required and might as well be constructed with relatively non-extensible material and eliminate the need for secondary means of preventing radial expansion of the outer shell. Such a solution would also serve the purpose of minimizing local bulging of the outer shell 201 as described below for the third mode of deformation.
[0058] Mode 3: Local Bulging of the Outer Shell:
[0059] Referring now to FIG. 9, this mode of deformation refers to the bulging of the outer shell 201 in the radial direction (R) between the aforementioned stiffening beam members 200 and any other additional stiffening elements (e.g., stiffening elements positioned between the beam members 201 ) as is shown in FIG. 9. This bulging occurs when a portion of the outer shell surface 205 is unsupported by such longitudinal and/or transverse stiffeners and is subject to pressure generated by the underlying balloons. Such local bulging of the outer shell 201 within two longitudinal beam members 200 while under balloon pressure 206 is shown in FIG. 9. Such bulging occurs even if the outer shell 201 is relatively non-extensible, but less severely.
[0060] Although such outward bulging can be reduced by reducing the distance between the beam members 200 , or by using a larger number of beam members 200 (with less bending stiffness) it is preferred that the bulging be minimized by adding transverse elements 250 to connect the beam members 200 at a number of positions along the length of the beam members as is shown in FIGS. 10 and 11. Thus, the transverse elements 250 extend in the circumferential direction (C) of the outer shell 201 . Although the transverse elements 250 are shown as simple straight elements they may be placed in any other pattern to bridge the beam members 200 as long as they result in smaller exposed outer shell areas, for instance in a crisscrossed pattern of elements 251 connecting the beam elements 200 . The transverse elements 250 may also be a solid plate connecting the beam members 200 . The solid plate having a length substantially equivalent to the length (L) of the outer shell 201 . Lastly, such outer bulging can be minimized by employing curved transverse elements 252 that are secured to the beam members 200 as shown in FIG. 11. Transverse element 251 is shown in FIG. 11 as extending concavely in the circumferential direction.
[0061] Mode 4: Change in the Shape of the Outer Shell Cross Section in the Radial Plane:
[0062] This mode of deformation refers to the situation in which the shape of the cross-section of the outer shell 201 of the applicator in the radial plane before the balloon is pressurized is non-circular, which is most often the case. In general, a non-circular shell under internal pressure (of the balloons for the present applicators) tends to become circular. As the outer shell 201 tends to become more circular, the area within the shell 201 cross-section and thereby the internal (enclosed) volume of the applicator would tend to increase.
[0063] To prevent such deformations the outer shell 201 can be enclosed with a structure that has a bending rigidity. A preferred implementation of such structures is a truss structure. However, since the structure has to be deformable while the applicator is being assembled around the limb, it is preferred that the structure be fully or partially formed with jointed (pin and/or spherical joints or their equivalent living joints) elements and rigidified during the assembly after it is placed around the applicator. For this reason., triangular truss structures or their equivalent are preferred. The schematic of such a structure 350 is shown in FIG. 12.
[0064] Referring now to FIG. 13, in practice, such a triangular truss structure 350 can be readily assembled around the, limb and is preferably constructed as a sheet member 510 of relatively hard material, such as plastic, and is preferably extruded. The sheet member 510 is preferably formed with triangular or other similar cross-sectioned truss elements 500 with appropriate stiffness in its plane and bending stiffness so that the truss elements 500 could take the place of the beam elements 200 . The truss elements 500 are extruded with a bottom sheet portion 503 with living joints 501 formed therein between each of the truss elements 500 so that the sheet member 510 can be formed into a circular or near circular configuration as shown in FIG. 12. The tops or top surface ridges 502 of the elements 500 are either roughened or provided with VELCRO.
[0065] Referring now to FIG. 14, during the assembly, the sheet member 510 is formed into the shape of the outer surface of the outer shell 201 and covered limb. An outer sheet 504 which can be a sheet made out of a relatively non-extensible material is preferably wrapped around the assembly to secure the sheet member 510 . The outer sheet 504 is held securely in place by means of outer straps (not shown) or the like. The outer layer 504 is preferably secured to the ridges 502 of the sheet member 510 by means of VELCRO, friction or the like. The desired triangular truss structure 350 is thus formed. For the truss structure 350 to provide the desired rigidity, the longitudinal sides 500 a of each element 500 should be relatively rigid and provide enough resistance to buckling. For this reason, the outer sheet 504 must be thick and have enough stiffness (e.g., stiffened by outer ribs) to withstand maximum compressive and bucking forces. As a result, all sides 500 a of the elements 500 and thereby the truss structure 350 is made rigid and can therefore resist change in its geometry as the balloon(s) 101 are pressurized.
[0066] Referring now to FIG. 15, to prevent a volume of the soft tissue to be pushed out of the sides of the applicator enclosure, segments of the limb before and after the applicator are prevented from “bulging out” by a means for preventing the tissue from bulging out of the first and second ends 103 , 104 . This can be readily accomplished by disposing a collar 601 on the limb or other body portion adjacent the first and second ends 103 , 104 . Preferably, the collar 601 comprises a relatively non-extensible sheet of flexible material 601 wrapped around the limb 603 at the first and second ends 103 , 104 of the applicator 600 . Obviously, the longer the length (l) of the wrapped elements 601 and the more resistant they are to the deformations described in the aforementioned modes, the more resistance they would provide to soft tissue displacement.
[0067] The applicator slippage problem is addressed by providing a means for preventing movement-of the applicator in the longitudinal direction (L), preferably, by ensuring that the surface of the applicator that is in contact with the limb (directly or through the intermediate layer of highly air permeable material) provides enough “frictional” or “sticktion” force to prevent its slippage towards the thinner segment of the limb. In addition or in place of such means of preventing slippage, the elements 601 are preferably used to provide the required resistance to slippage. This can be accomplished by selecting a material for elements 601 or by coating the surfaces that are in contact with the limb surface with materials that provide enough friction or sticktion between the elements 601 and the limb surface. In which case, the ends of the applicator have to be secured to the elements 601 directly or by the intermediate sheets of flexible material 602 , which is preferably wrapped around the first and second ends 103 , 104 and the portions of the body adjacent the applicator (or alternatively, the collars 601 ).
[0068] While there has been shown and described what is considered to be preferred embodiments of the invention, it will, of course, be understood that various modifications and changes in form or detail could readily be made without departing from the spirit of the invention. It is therefore intended that the invention be not limited to the exact forms described and illustrated, but should be constructed to cover all modifications that may fall within the scope of the appended claims. | An applicator for applying an external counterpulsation to a body portion is provided. The applicator including: an outer shell for covering the body portion, the outer shell having a length in a longitudinal direction and a circumference in a circumferential direction; a balloon disposed in the outer shell, pressurization of which applies an external pressure to the body portion; and at least one anti-deformation member for reducing an amount of deformation of the outer shell caused by the pressurization of the balloon. | 0 |
CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is the US National Stage of International Application No. PCT/EP2012/050604 filed Jan. 17, 2012 and claims benefit thereof, the entire content of which is hereby incorporated herein by reference. The International Application claims priority to the European application No. 11152648.9 EP filed Jan. 31, 2011, the entire contents of which is hereby incorporated herein by reference.
FIELD OF INVENTION
[0002] The present invention relates to an energy store for storing and emitting electrical energy. In addition, the invention relates to a method for discharging and charging such an energy store.
BACKGROUND OF INVENTION
[0003] Energy stores for storing and emitting electrical energy are, for example, of great importance for many mobile applications. While the storage capacity of current energy stores is sufficient for the storage of electrical energy for the operation of smaller devices such as cell phones, portable computers, etc., energy stores for the storage of electrical energy for larger applications such as, for example, electrically powered vehicles are still fraught with imperfections which preclude their successful use in a commercial context. In particular, the storage capacity of the batteries used does not yet meet the desired requirements. Although, for example, lithium ion batteries achieve good results for use in cell phones or computers, for instance, they are not wholly suitable for electric vehicles with their high energy requirements. The storage capacity of lithium ion batteries is a limiting factor for the range of an electric vehicle. As the size of the battery in the vehicle cannot be increased at will, the range remains limited.
[0004] In the automotive field in particular, systems are also known in which the energy necessary for propulsion is stored in the form of hydrogen. By means of a fuel cell the hydrogen is then converted into electric current with which the engine can be driven.
[0005] For such technology, however, the construction of a fueling station network for hydrogen is necessary, making the introduction of this technology expensive, in particular with regard to the stringent safety requirements for fueling stations due to the risk of explosion.
SUMMARY OF INVENTION
[0006] Compared with this prior art, the object of the present invention is to provide an advantageous energy store and an advantageous method for discharging and charging an energy store. In addition, an object of the present invention is to provide an advantageous electrical system with an electrical load.
[0007] The above objects are achieved by the features of the independent claim(s). The dependent claims contain advantageous embodiments of the invention.
[0008] An energy store according to the invention comprises a rechargeable primary energy store and a secondary energy store. The primary energy store comprises a first electrode which generates anions and which conducts anions, a second electrode which accepts anions and/or which conducts anions and an electrolyte typically designed as solid matter which is arranged between the first electrode and the second electrode and which conducts anions. In addition, the primary energy store comprises a first redox pair which forms the second electrode or is in contact with same and which comprises an oxidation reactant and an oxidation product. Furthermore, the energy store according to the invention comprises at least one storable second oxidation reactant that belongs to a second redox pair. The secondary energy store is designed as a store for the second oxidation reactant.
[0009] Between the primary energy store and the secondary energy store there is a connecting line allowing the second oxidation reactant to be conducted from the primary energy store to the secondary energy store and back. A metal and its oxide or two different oxidation states of a metal, for example, can be used as the first redox pair.
[0010] The second oxidation reactant may in particular be gaseous. A suitable second oxidation reactant is, for example, hydrogen. By means of a compressor present between the primary energy store and the secondary energy store for compressing the secondary oxidation reactant a particularly high storage capacity can be achieved for the gaseous oxidation reactant in the second energy store. For the storage of a gaseous second oxidation reactant in particular there may be a high-pressure gas reservoir or a metal-hydride storage unit.
[0011] According to the invention a rechargeable battery, the design of which corresponds to a fuel cell, in particular a solid oxide fuel cell (SOFC), is therefore operated in an additional operating mode as a fuel cell or electrolyzer for a redox pair such as, for example, H 2 O/H 2 . In the battery electrical energy is stored in the form of a typically solid, but sometimes also liquid redox pair, wherein the redox pair in the fully charging state only comprises the reduced portion, in other words the oxidation reactant, and in the discharging state the oxidized part, in other words the oxidation product. To emit energy the oxidation reactant is, for example, oxidized by means of atmospheric oxygen, wherein the atmospheric oxygen is ionized by the first electrode, the oxygen ions are conducted via the first electrode to the electrolyte permeable for the oxygen ions and after passage through the electrolyte oxidize the oxidation reactant.
[0012] The oxidation reactant can be either the material of the second electrode itself or a material in contact with said electrode. In the latter case, the second electrode conducts anions. It should be noted here that the use of atmospheric oxygen for oxidation is only chosen as an illustrative example and that instead of oxygen ions, use can also be made of other anions in principle.
[0013] When the oxidation reactant of the first redox pair has fully oxidized and no more current flow based on further oxidation of this redox pair is therefore possible, in the additional operating mode the oxidation reactant of a second oxidation pair, for example hydrogen, can be supplied to the second electrode, the battery then operating as a fuel cell. On the second electrode oxidation of the second oxidation reactant then takes place with the emission of electrons which are conducted back to the first electrode via a circuit. In this way, emission of electricity from the energy store can be extended until the second oxidation reactant has been exhausted.
[0014] To charge the energy store or recharge the energy store, the first and second electrode are connected to a power supply, the polarity being selected such that the material of the first redox pair is reduced on account of the power supply. After the material of the first redox pair has been completely reduced and the primary energy store has therefore been recharged, in the additional operating mode an oxidation product of the second redox pair can be supplied to the second electrode and the battery operated as an electrolyzer. When using hydrogen as a second oxidation reactant, water vapor, for example, can be supplied as an oxidation product.
[0015] On account of the current flow through the electrodes, electrolysis of the oxidation product of the second redox pair takes place so that the oxidation reactant of the second redox pair arises, which can then be stored in the second energy store.
[0016] The oxidation product of the second redox pair arising during discharging of the energy store need not necessarily be identical to the oxidation product of the second redox pair used for charging. For example, the oxidation product of the second redox pair arising during discharging can be discharged into the environment. To this end the energy store may have an outlet for the discharge of the oxidation product of the second redox pair. If the oxidation product of the second redox pair which arises during discharging is discharged into the environment, an oxidation product of the second redox pair must be newly supplied to charge the energy store. To this end the energy store may have an inlet for the supply of an oxidation product of the second redox pair. The outlet for the discharge of the oxidation product of the second redox pair arising during discharging and the inlet for the supply of the oxidation product of the second redox pair during charging of the energy store may be identical in particular. The embodiment in which the oxidation product of the second redox pair arising during discharging is discharged into the environment is suitable in particular if the oxidation product is environmentally compatible and can be obtained without great expenditure. This is the case, for instance, when hydrogen is used as an oxidation reactant. When atmospheric oxygen is used for oxidation, for example, water vapor is produced as an oxidation product which can be discharged without damage to the environment. In addition, water vapor for introduction into the energy store during charging is available without great expense.
[0017] In particular, if the oxidation product arising during discharging of the energy store is not readily environmentally compatible or the oxidation product can only be obtained at great expense during charging of the energy store, it is advantageous if the energy store includes a reservoir for collecting the oxidation product of the second redox pair and a connecting line between the primary energy store and the reservoir which enables the conducting of the second oxidation product from the primary energy store to the reservoir. The oxidation product collected in the reservoir can then be reused while the energy store is being charged.
[0018] An electrical system with an electrical load according to the invention is equipped with at least one energy store according to the invention. In particular, the load may be an electrically driven device, for instance an electric motor. In addition, it is advantageous if the energy store is designed to be replaceable, as then a stoppage of electrical consumption during the charging time necessary for the charging of the energy store can be avoided.
[0019] The use of an energy store according to the invention enables the system to fall back on an energy store with a high charging capacity, thus permitting the electrical device to have an extended life without recharging the energy store.
[0020] In the method according to the invention for discharging and charging an energy store according to the invention, during discharging the primary energy store is first discharged while emitting electrical energy, by the first oxidation reactant being oxidized to the first oxidation product. Then the second oxidation reactant from the secondary energy store is supplied to the primary energy store for the further emission of electrical energy.
[0021] This is then oxidized to the oxidation product of the second redox pair on the second electrode. When charging the energy store, first the primary energy store is charged while consuming electrical energy, with the first oxidation product of the first redox pair being reduced to the first oxidation reactant. Then while continuing to consume electrical energy an oxidation product of the second redox pair is supplied to the primary energy store, and is reduced on the second electrode to the second oxidation reactant. The oxidation reactant arising on the second electrode is conducted into the second energy store for storage.
[0022] As a result of the primary energy store being operated as an electrolyzer after charging of the primary energy store, the charging capacity of the energy store can be increased. Likewise, as a result of operation as a fuel cell the duration of current output can be extended after discharging of the first energy store.
[0023] To increase the storage capacity of the secondary energy store for a given volume, in the case of a gaseous second oxidation reactant compression of the second oxidation reactant before storage in the secondary energy store may take place.
[0024] The oxidation product of the second redox pair arising during discharging of the energy store may either be discharged into the environment or conducted to a reservoir and collected there. The latter is advantageous in particular if the oxidation product arising during discharging of the energy store is not environmentally friendly or an oxidation product for charging the energy store cannot be provided without relatively great expense. The oxidation product collected in the reservoir is then available for reuse during charging.
BRIEF DESCRIPTION OF THE DRAWINGS
[0025] Additional features, properties and advantages of the present invention are emerge from the following description of exemplary embodiments with reference to the attached figures.
[0026] FIG. 1 shows an example of a primary energy store of the energy store according to the invention.
[0027] FIG. 2 shows an energy store according to the invention in highly schematized form.
[0028] FIG. 3 shows the energy store from FIG. 2 in a first discharge mode.
[0029] FIG. 4 shows the energy store from FIG. 2 in a second discharge mode.
[0030] FIG. 5 shows the energy store from FIG. 2 in a first charge mode.
[0031] FIG. 6 shows the energy store from FIG. 2 in a second charge mode.
DETAILED DESCRIPTION OF INVENTION
[0032] Hereinafter the present invention is explained in more detail on the basis of a highly schematized exemplary embodiment shown in FIGS. 1 to 6 . First an explanation is provided of the primary energy store and its operation on the basis of FIG. 1 . On the basis of FIGS. 2 to 6 the structure of the energy store according to the invention and its operation is then explained.
[0033] The primary energy store of an energy store according to the invention is shown in a highly schematized manner in FIG. 1 . Within the framework of the exemplary embodiment a primary energy store is described which is equipped with a metal and a metal oxide as the first redox pair and in which oxidation is performed with the aid of atmospheric oxygen. However, it should be noted here that the first redox pair need not necessarily comprise a metal and a metal oxide but, for example, two metal oxides with different oxidation states or a non-metallic oxidation reactant Likewise, the oxidizing agent need not necessarily be atmospheric oxygen. Other gases or liquids forming anions may also be used in oxidation. Instead of two-fold negatively charged oxygen ions, oxidation then takes place on the basis of another singly or multiply negatively charged ion, for example CO 3 2− or PO 4 3− . In addition, other elements or compounds forming anions, for instance, fluorine or chlorine and fluorine or chlorine compounds, can also be used for oxidation. However, atmospheric oxygen is particularly suitable as an oxidizing agent as it is available everywhere in abundance and does not damage the environment.
[0034] In the present exemplary embodiment, the primary energy store 1 comprises a first electrode 3 which is arranged in such a way that air can be fed past it. It is made of an Oxygen Transporting Material, OTM for short, which generates oxygen ions O 2− from the atmospheric oxygen and is also able to conduct the oxygen ions. Examples of suitable materials for the first electrode 3 , hereinafter referred to as an air electrode, are perovskite (ABO 3 ) or zirconium oxide, which is doped with scandium oxide or yttrium oxide (ScSZ and YSZ) as well as combinations thereof.
[0035] The primary energy store comprises a second electrode which accepts and/or conducts the oxygen ions and which in the present exemplary embodiment consists of a metal, for instance iron, which is oxidized by the oxygen ions. Alternatively, the second electrode 5 may also consist of a material conducting oxygen ions such as, for example, perovskite, which has a sponge-like or scaffold-like structure. In this case, a liquid redox pair may be used into which the second electrode is immersed. As the second electrode in the present exemplary embodiment is made of a redox pair formed by a metal and a metal oxide, wherein depending on the state of charge of the primary energy store it consists of metal, metal oxide or a mixture of both, it is hereinafter referred to as a metal electrode 5 .
[0036] An electrolyte layer 7 is arranged between the air electrode 3 and the metal electrode 5 , and in the present exemplary embodiment is a ceramic membrane transporting oxygen ions. For example, it may be made of a single phase of zirconium oxide which is stabilized with scandium oxide or yttrium oxide. Alternatively mixtures of yttrium oxide which is doped with zirconium oxide and yttrium oxide which is doped with scandium oxide may also be used.
[0037] When discharging the primary energy store, oxygen ions O 2− are formed from the air fed past the air electrode 3 , wherein electrons are absorbed by the oxygen from the material of the air electrode to form anions. The consequent oxygen ions migrate through the electrolyte layer 7 to the metal electrode 5 where they oxidize the metal while emitting electrons. The surfeit of electrons thus arising in the metal electrode is conducted to the air electrode 3 by the interposition of an electrical load 9 . The reactions taking place during the discharging process are shown in the upper half of FIG. 1 .
[0038] The charging process and the reactions taking place at the same time are shown in the lower half of FIG. 1 . Instead of an electrical load, a power supply 11 is connected to the electrodes 3 , 5 to charge the primary load, wherein the negative terminal is connected to the metal electrode and the positive terminal to the air electrode. By means of the electrons flowing to the metal electrode, the metal oxide is reduced, releasing oxygen ions which migrate through the electrolyte layer 7 to the air electrode 3 . In the air electrode 3 , which is connected to the positive terminal of the energy source 11 , the electrons are emitted by the oxygen ions so that molecular oxygen is formed, which is emitted by the air electrode 3 to the environment. If the metal oxide of the metal electrode 5 is completely reduced to metal, additional charging of the primary energy store is not possible.
[0039] In order to then be able to continue to charge the energy store according to the invention even if the metal oxide has been completely reduced, the energy store comprises a secondary energy store 13 which is connected via a gas line 17 to a housing 15 , which encloses the metal electrode 5 (cf. FIG. 2 ). In addition, the housing 15 has an inlet/outlet 19 via which a gas or vapor can be discharged into or out of the inside of the housing 15 . For additional charging of the energy store according to the invention, a second, typically gaseous redox pair is used. In the present exemplary embodiment this second redox pair is formed from hydrogen and water vapor. However, other redox pairs, in particular gaseous redox pairs can also be considered. But liquid redox pairs are not ruled out entirely either.
[0040] In the present exemplary embodiment water vapor is fed through the inlet/outlet 19 into the inside of the housing 15 for further charging of the energy store according to the invention. At the same time the primary energy store remains connected to the power supply, as shown in the lower half of FIG. 1 . Instead of a further reduction of the metal, a reduction of the water vapor introduced into the inside of the housing 15 to hydrogen now takes place, which by means of a compressor 21 arranged in the gas line 17 is introduced into the secondary energy store 13 , which in the present exemplary embodiment is designed as a high-pressure gas reservoir. The oxygen ions arising during reduction of the water vapor are in turn forwarded via the electrolyte layer 7 to the air electrode 3 and there converted to molecular oxygen which is discharged into the environment. For additional charging of the energy store according to the invention the primary energy store is therefore used as an electrolyzer for the electrolysis of water vapor. Electrolysis and storage of the hydrogen can take place until the secondary energy store 13 is completely filled with hydrogen. Only then is the energy store according to the invention fully charged.
[0041] Although a high-pressure gas reservoir is used in the present exemplary embodiment for the storage of hydrogen, other embodiments are also possible. For example, the secondary energy store can be designed as a metal-hydride storage unit. Likewise, the second redox pair does not need to consist of water vapor and hydrogen. Thus, the hydrogen can be replaced by methane, for example. Likewise, the water vapor can be replaced by another component, for example by hydrogen fluoride. However, the use of water vapor as a component of the redox pair is advantageous from environmental perspectives. In addition, the oxidation product used for charging may be distinguished from the oxidation product arising during discharging. A redox pair within the meaning of the present invention may therefore also comprise more than one oxidation product.
[0042] However, it is advantageous if both oxidation products are identical as then a complete material cycle can be realized.
[0043] The discharging of a fully charged energy store according to the invention is shown in FIGS. 3 and 4 , the complete recharging of the energy store in FIGS. 5 and 6 . When discharging the energy store according to the invention, in other words during consumption of electrical energy by a load 9 connected to the electrodes 3 , 5 of the primary energy store 1 , first the primary energy store is discharged by means of oxidation of the metal electrode 5 . This discharge mode is shown in FIG. 3 .
[0044] If the primary energy store 1 is discharged, hydrogen from the secondary energy store 13 is supplied to the inside of the housing 15 , and is oxidized into water vapor on the now oxidized metal electrode 5 by the oxygen ions obtained in the air electrode 3 . The water vapor is finally discharged via the inlet/outlet 19 to the environment. This mode of discharge, which is schematically represented in FIG. 4 , can be continued until the secondary energy store 13 is unable to discharge any more hydrogen.
[0045] To charge the energy store according to the invention, instead of the load 9 a power supply 11 is connected to the primary energy store 1 , as shown in the lower half of FIG. 1 . With the aid of this power supply, the metal oxide of the metal electrode 5 is reduced to metal. This charging mode is shown in FIG. 5 . If a further reduction of the metal electrode 5 is not possible, water vapor is injected into the inside of the housing 15 via the inlet/outlet 19 and is reduced to hydrogen until the secondary energy store 13 has been completely filled. This charging mode is shown in FIG. 6 .
[0046] In addition to the modifications of the exemplary embodiment already described, further modifications are possible. Thus, for example, a reservoir 23 which is connected via a connecting line 25 to the inside of the housing 15 (shown by a dotted line in FIG. 2 ) may be available for the water vapor arising during the discharging of the secondary store, in which reservoir 23 the water vapor is collected so that it can be reused when charging the secondary energy store. This embodiment is advantageous in particular if the second redox pair does not contain any water vapor as an oxidation product but an oxidation product which should not be discharged into the environment, whether because it is environmentally damaging or because it is not readily obtainable for recharging the secondary energy store.
[0047] The energy store according to the invention is suitable, for example, for mobile applications, in particular for electrically powered vehicles. In this case, the load 9 shown in FIG. 1 is an electric motor. But other mobile or non-mobile electrical systems which have an electrical load such as, for example, an electric motor or other electrically powered devices, may also have an energy store according to the invention for the supply of energy. Mobile medical devices or lamps are conceivable, for example.
[0048] In addition, it is possible to design the energy store to be replaceable so that a fully discharged energy store can be replaced by a new, charged energy store. In this way, stoppages can be avoided when charging the energy store. Alternatively, there is the option of such an electrical system having more than one energy store according to the invention, in particular two energy stores.
[0049] Then one energy store can be charged while the other energy store supplies the electrical load with power. In particular, the exemplary embodiment with at least two energy stores is practical for stationary electrical systems, whereas the version with a replaceable energy store according to the invention is advantageous in mobile applications. | An energy store includes a rechargeable primary energy store having a first electrode which generates anions and which conducts anions, a second electrode which accepts anions and/or which conducts anions, an electrolyte which is arranged between the first electrode and the second electrode and which conducts anions and is embodied as a solid, and a first redox pair which forms the second electrode or is in contact with same and which includes an oxidation reactant and an oxidation product. The store includes at least one storable second oxidation reactant that belongs to a second redox pair and a secondary energy store which is designed as a store for the second oxidation reactant. A connecting line is provided between the primary energy store and the secondary energy store, the connecting line allowing the second oxidation reactant to be conducted from the primary energy store to the secondary energy store and back. | 8 |
CROSS-REFERENCE TO RELATED APPLICATION
This is a continuation of my U.S. patent application Ser. No. 07/970,140, filed Nov. 2, 1992 now abandoned.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to a method for processing signals, in particular audio signals for hearing aids.
2. The Prior Art
A recurring problem in the transmission and amplification of audio signals is the adjustment of the volume to the respective requirements. This problem also arises in the transmission of other signals, such as data signals via modems, for example.
There is a special problem concerning hearing aids in that very low noises have to be amplified very strongly in order to be noticed by the user. However, in some cases loud noises are amplified too strongly, which can be very unpleasant for the user.
A whole range of methods are known for the compression of the signals. These methods have the disadvantage that they require a certain response time. This leads to a delay in the response behavior. Generally, such a delay is not desirable because in this way very quiet sounds that occur directly after louder sounds are covered up.
A further disadvantage consists of the fact that such circuits for compressing the volume are often insufficiently adjustable and controllable or not adjustable at all.
SUMMARY OF THE INVENTION
It is the object of the present invention to avoid these disadvantages and to create a method with which signal processing without reactions times is possible.
In accordance with the invention it is therefore provided that at first a momentary amplitude signal A(t) is generated which is equivalent to the amplitude of the input signal u i (t) and that said momentary amplitude signal A(t) is used for processing the input signal u i (t). Because said momentary amplitude signal A(t) is available in real time, it is possible to carry out the signal processing free of delays. Depending on the requirements it is possible to achieve a compression or expansion of the volume.
A compression of the volume is achieved if the input signal u i (t) is divided by the momentary amplitude signal A(t) which, if required, is multiplied by a constant K. The constant K prevents division by zero. If the constant K is chosen sufficiently small, the output signal has a practically constant amplitude, i.e., a minute volume range. This may be desirable in the case of data transmission systems that use telephone lines.
A particularly simple and far-reaching controllability of signal processing can be achieved by using the momentary amplitude signal A(t) for controlling the amplification of the input signal u i (t).
In a particularly favorable embodiment of the method in accordance with the invention the following steps are provided:
Generation of an analytical signal, consisting of two Hilbert signals h 1 (t), h 2 (t), whose energy spectrum is equivalent to that of the input signal u i (t).
Formation of the square root of the sum of the squares of the two Hilbert signals h 1 (t) and h 2 (t).
An analytical signal is designated as a complex signal whose imaginary component represents the Hilbert transformation of the real component. The mathematical basics are known and have been explained in detail in R. B. Randall: "Frequency Analysis", Bruel & Kjaer, 1987, for example. Due to this property the two components of the analytical signal will be referred to in short as Hilbert signals.
The Hilbert transformation produces from one function another function whose amplitude spectrum is identical, but whose phase relation is displaced in all frequencies by π/2. Principally it would be possible to subject the input signal to such a Hilbert transformation. This, however, is very difficult to realize in a circuit. Nevertheless it is easily possible to generate two output signals that both coincide with the input signal in the amplitude spectrum and whose phase relationship between the two output signals is shifted by π/2. The momentary amplitude signal A(t) is gained in such a way that the square root is formed by the sum of the squares of the two Hilbert signals h 1 (t) and h 2 (t).
Furthermore, the invention relates to an apparatus for processing signals, in particular audio signals for hearing aids. The apparatus is arranged in accordance with the invention in such a way that an amplitude signal circuit is provided with which a momentary amplitude signal A(t) is produceable whose momentary strength is substantially proportional to the momentary amplitude of the input signal u i (t) and that furthermore a logic element is provided in which said amplitude signal A(t) is combined with the input signal u i (t).
It is preferable if the logic element comprises a divider circuit in which the input signal u i (t) can be divided by the momentary amplitude signal A(t). In this way a strong reduction of the volume range is achieved.
To prevent division by zero an adder as well as an adjustable signal source may be provided, whereby the output of the amplitude signal circuit and the adjustable signal source are connected to the inputs of the adder.
In a preferable embodiment of the invention it is provided that a non-linear transformer is connected to the output of the amplitude signal circuit, which transformer controls a voltage-controlled amplifier for the input signal u i (t). Depending on the characteristics of the non-linear transformer it is possible to realize any desired transforming function. In combination with the non-linear transformer the voltage-controlled amplifier forms the logic element.
It may also be provided that a timer is connected in series with the non-linear transformer. Said timer, which can be a lag or delay unit, also allows processing based on the slope of signal rises.
Preferably, the amplitude signal circuit comprises the following components:
a Hilbert circuit (HS) with two outputs which are supplied with two Hilbert signals h 1 (t) and h 2 (t) gained from an input signal u i (t), which Hilbert signals represent the components of an analytical signal;
a logic circuit which with its two inputs are connected to the outputs of the Hilbert circuit and which produces an output signal A(t) according to the following algorithm from the two signals h 1 (t) and h 2 (t) that are supplied to the inputs: ##EQU1##
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is now outlined in greater detail by reference to the embodiments schematically represented in the Figures:
FIGS. 1a, 1b, 2 and 3 show block diagrams of various embodiments of the invention;
FIG. 4 shows a block diagram of the Hilbert circuit;
FIG. 5 shows an embodiment of the Hilbert circuit;
FIG. 6 shows a block diagram of a variation of the Hilbert circuit;
FIG. 7 shows an embodiment of the logic circuit;
FIGS. 8 and 9 show diagrams of the input and output signals.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the embodiment of the invention as shown in FIG. 1 two Hilbert signals h 1 (t) and h 2 (t) are gained from the input signal u i (t) by means of the Hilbert circuit HS.
A logic circuit VS is connected with its two inputs to the outputs of the Hilbert circuits. Logic circuit VS produces from the signals h 1 (t) and h 2 (t) that are supplied to the inputs an output signal A(t) according to the following algorithm where V indicates the voltage of the Hilbert signals: ##EQU2##
This momentary amplitude signal A(t) is further processed in the logic element VG. It is increased in an adder ADD by a constant signal K which is produced by an adjustable signal source Q. The following operation is carried out in a divider circuit DS:
u.sub.o (t)=h.sub.1 (t)/(A(t)+K).
With respect to the final result it is not important whether the input signal u i (t) or, as represented in FIG. 1, a Hilbert signal h 1 (t) is used as dividend.
Such a circuit is equivalent to a compressor without transient or decay periods which does not cause distortions for an isolated sound. In the event that several sinusoidal components exist side by side, it is obvious that intermodulation distortions will occur. Despite this, however, the output signal still sounds substantially natural because similar distortions occur in the concha of the human ear.
In the embodiment as shown in FIG. 2 the momentary amplitude signal A(t) is supplied via a non-linear transformer NLP to a voltage-controlled amplifier VCA. Said amplifier VCA amplifies the input signal u i (t) depending on signal n(A(t)) which is supplied to the output of the non-linear transformer NLP. Depending on the characteristics of the non-linear transformer NLP it is possible to set any desired volume behavior. In addition, this also allows providing a control, such as one that depends on the frequency or manual settings.
In FIG. 3 a delay unit T is arranged behind the non-linear transformer NLP. This provides the option of also realizing time-selective transforming functions.
FIG. 4 shows that the Hilbert circuit HS can be arranged by at least two all-passes AP 1 , AP 2 . The transforming behaviour of all-passes AP 1 , AP 2 is selected in such a way that Hilbert signals h 1 (t) and h 2 (t) are supplied to the two outputs within the desired frequency range, of which Hilbert signals a signal h 1 (t) or h 2 (t) represents substantially the Hilbert transformation of the respective other signal h 2 (t) or h 1 (t).
FIG. 5 shows in detail the possible arrangement of the Hilbert circuit HS in accordance with FIG. 4. In this circuit the input IN is connected in the known manner with an amplifier 1 and a bridge circuit 2 whose two branches are connected with the output of amplifier 1.
The two branches of the bridge circuit 2 are each formed by a resistor 3, 4 with a capacitor 5, 6 and by the coupling in parallel of a resistor 7, 8 with a condensor 9, 10 which is connected to each of said branch, the components in both branches being provided with different dimensions. The two output signals h 1 (t) and h 2 (t) are tapped from the connecting points of the series R/C elements with the parallel R/C elements. Resistors and capacitors should be selected with suitable ratings.
If the frequency range for the Hilbert transformation is not sufficiently narrow in accordance with FIGS. 4 and 5, a frequency separating filter FW may be provided which, for example, consists of a highpass HP and lowpass TP, as is shown in FIG. 6. The partial signals p(t) and q(t) are transformed separately by means of several pairs of all-passes AP 1 , AP 2 ; AP 3 , AP 4 and added thereafter in order to obtain the Hilbert signals h 1 (t) and h 2 (t).
FIG. 7 shows a logic circuit which generates the signal: ##EQU3## on output A 1 from the signals h 1 (t) and h 2 (t) that are supplied to inputs E 1 and E 2 .
Such a circuit is known from FERRANTI: Analog IC-Design, 1980, for example. It consists of two series connections of transistors T11, T12, T21 and T22 whose bases are connected with their collectors. The input signals h 1 (t) and h 2 (t) to be combined are supplied to said series circuits. Said series connections are further connected to the bases of two transistors T3, T4 connected in parallel. A further transistor T5 is connected to these in series. The base of transistor T5 is connected to its collector. A current A(t), which is equivalent to ##EQU4## flows through the transistors T3, T4, whereby h 1 (t) and h 2 (t) are the input currents.
The circuit in accordance with the invention, in particular in the embodiment of FIG. 1, acts as contrast amplifier which suppresses noise. FIG. 8 shows that the response time is actually virtually zero. The upper curve shows the input signal u i (t), the lower curve shows the output signal u o (t). The input signal u i (t) is zero during the first period Z 1 , small during the second period Z 2 , and large during the third period Z 3 . The amplitude of the output signal is substantially independent of the amplitude of the input signal.
FIG. 9 shows the effect as contrast amplifier. The upper curves shows the input signal u i (t), the lower the output signal u o (t). The input signal u i (t) consists of a rectangular signal with an overlaid sinusoidal oscillation. In the output signal u o (t) represented below, the rectangular signal is still clearly visible, whereas the sinusoidal signal has substantially been smoothed.
The two lower curves of FIG. 9 show the spectral distribution of the input signal u i (t) and the output signal u o (t). The important aspect is that in the input signal u i (t) the peak value is approx. 13 dB over the minimum value, whereas in the output signal u o (t) the peak value is approx. 19 dB over the minimum value. | Method and apparatus for processing signals, in particular audio signals for hearing aids. A delay-free processing of signals is achieved in that at first a momentary amplitude signal A(t) is produced whose strength is proportional to the momentary amplitude of the input signal u i (t) and that the momentary amplitude signal A(t) is used for processing the input signal u i (t). | 7 |
FIELD OF THE INVENTION
The present invention pertains to a process for sewing a flap with rough closing edge and a pocket on a fabric part in one operation and to an automatic sewing machine for carrying out this process.
BACKGROUND OF THE INVENTION
The conventional sewing of a flap with a rough closing edge on a fabric part with a pocket placed on in advance is carried out, as is shown in FIGS. 4 and 5, in two partial steps. In a first partial step, the flap 10 with its rough closing edge 14, being in a rotated position in relation to the finished position of use 11, is aligned at a predetermined distance from the sewn-on pocket 9, taking into account the course of the pattern 17 of the fabric part, pocket and flap, and is connected to the fabric part 6 by means of a fastening seam 12. The flap 10 is then rotated by 180° into its position of use 11 around this fastening seam 12 in the second partial step and is connected to the fabric part 6 with a cover seam (top seam) 13, and the distance 15 between the cover seam 13 and the fastening seam 12 is selected to be such that the rough closing edge 14 of the flap 11 placed on in the finished position is no longer visible. This operation, which is carried out freely guided by hand, requires a high skill on the part of the seamstress to maintain the specified position of the flap 11 in relation to the pocket 9 and also to make the course 17 of the stripes or checks to be congruent within the specified tolerances in the case of figured fabrics. The process used here is extraordinarily time-consuming and requires a very large amount of training in order to meet the quality specifications and the required output.
A process and an automatic sewing machine for sewing a flap on a fabric part, in which the flap has a folded (clean) closing edge, is described in the patent DE 41 24 164 C2. In this case, the flap is pre-positioned in an offset parking position in relation to the pocket and is displaced into the position of use proper after the pocket has been sewn on, and is then sewn on. This process is not suitable for sewing on a flap with a rough closing edge for quality reasons, because the rough closing edge is visible after the flap has been sewn on.
SUMMARY AND OBJECTS OF THE INVENTION
The basic object of the present invention is to provide a process for sewing a flap with a rough closing edge together with a pocket on a fabric part in one operation and an automatic sewing machine for carrying out this process, in which the alignment and the sewing on of the flap with a rough closing edge are performed in a short time and with a simple device.
This object is accomplished according to the present invention in a process of the type described in the introduction by providing and positioning the flap with a rough closing edge in a rotated position in relation to a final position or "position of use" on the fabric part. The fabric part and the flap are then transported in fixed association with one another to a sewing machine with a sewing position. The flap is connected to the fabric part by means of a first flap seam. The flap is then rotated around the first flap seam into a final position, "position of use", and the flap is connected to the fabric part by means of a second flap seam at a distance spaced from said first flap seam.
The flap is aligned according to the pattern according to the fabric part inserted in advance and the positioned pocket cut in a rotated sew-on position in relation to its finished position of use relative to the fabric part and the pocket cut. The order of the alignment processes of the individual parts in relation to one another is extensively free. After folding the pocket cut and the sewing onto the fabric part, which may be a shirt part, a blouse part or a pant part, the positioned flap is sewn on with a first fastening seam and is then rotated into its position of use around this fastening seam, and it is subsequently connected to the fabric part by means of a cover seam such that the rough closing edge of the flap is no longer visible. As a result, a reduction in the overall processing time (process time and idle time) of the fabric part, pocket cut and flap through the manufacturing area is achieved, because operations that were previously carried out at separate workplaces are integrated in one clamping.
This leads to a reduction of the costs. At the same time, this leads to an improvement in quality, because the risk of the flap not having an exact position relative to the pocket cut and the fabric part after the alignment process is reduced due to the clamped guiding of the seam.
An automatic sewing machine only connecting the flap and not positioning or connecting the pocket cut is also provided for carrying out the process. Contrary to the currently known positioning of a pocket cut in relation to a fabric part and the subsequent folding of the pocket cut and the sewing of these two parts, only the flap must be additionally inserted. The device is designed as such a flexible device that it can, of course, also be used when only pocket cuts without flaps are to be sewn on. The shape and the position of the fastening and cover seams by means of which the flap is fastened to the fabric part may be readily varied.
The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this disclosure. For a better understanding of the invention, its operating advantages and specific objects attained by its uses, reference is made to the accompanying drawings and descriptive matter in which preferred embodiments of the invention are illustrated.
BRIEF DESCRIPTION OF THE DRAWINGS
In the drawings:
FIG. 1 is a partially cutaway representation of the top view of an automatic sewing machine according to the present invention;
FIG. 2 is a side view A-B of the preparation station (loading station) 2 with the folding device;
FIG. 3 is the side view A-B of a variant of the preparation station 2 with the folding device;
FIG. 4 is a shirt with the pocket and flap sewn on in the rotated position with the fastening seam;
FIG. 5a is a shirt with the pocket and flap sewn on in the position of use with the cover seam;
FIG. 5b is the pocket and flap in the position of use with two cover seams and pencil opening (design variant to FIG. 5);
FIG. 6a is a side view of the fabric holder and sewing machine in a sectional representation C-D;
FIG. 6b is the flap-gripping system in a sectional representation along L-M;
FIG. 7 is the side view (sectional representation E-F) of the fabric holder with the turning slide extended;
FIG. 8 is the top view of the fabric holder with the turning slide extended;
FIG. 9 is the side view (sectional representation G-H) of the fabric holder with the turning slide withdrawn;
FIG. 10 is the top view of the fabric holder with the turning slide withdrawn;
FIG. 11 is the side view (sectional representation I-K) of the fabric holder with the folding slide withdrawn; and
FIG. 12 is the top view of the fabric holder with the folding slide withdrawn.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The automatic sewing machine shown in FIGS. 1 and 2 has a frame 1, on which a preparation station with a folding device 2 (loading station), a sewing machine 3, and a fabric guide unit 4 is stationarily arranged. The fabric part 6, which may be, e.g., a shirt front part, is positioned in the preparation station 2 on the fabric support plate 5 according to corresponding line marks 7 and 7'. The pocket cut 8 is positioned on a thin folding plate 22 made of spring steel at the stop 23, aligned with the fabric part 6 according to the pattern, and is held in the position necessary for folding and sewing in relation to the fabric part 6 by the elastic clamps 24 and 24'. For the alignment according to pattern of the fabric parts in relation to one another, the folding plate 22 is perforated by a window 27, through which the course of the pattern 18 of the fabric parts to be sewn together can be traced. The folding device or tools 32, which are necessary for folding the pocket cut 8, are shown only partially, and by means of which the pocket cut 8 is folded and positioned in the correct position on the lower fabric part 6, are accommodated in the support 31 projecting freely over the fabric support 5. Such folding devices have been generally known and are widespread in practice, so that a detailed description is not necessary. The following documents may be referred to as examples: DE 37 09 264 A1 (corresponding to U.S. Pat. No. 4,813,362), DE 37 09 210 A1 (corresponding to U.S. Pat. No. 4,793,272), and DE 37 09 251 A1 (corresponding to U.S. Pat. No. 4,785,749), and incorporated by reference.
The folding plate 22 is connected to a step-like positioning support 102 to form a changing unit, which is fastened to the guide support 105 via the pins 103 and 103' by means of the screw 104. In its sew-on position, which is rotated by 180° in relation to its finished position of use, the flap 10 is aligned on the positioning surface 25 with the fabric part 6 and the pocket cut 8 according to the pattern at the stop 26 and is held in position by the elastic clamps 28 and 28'.
FIG. 3 shows another possibility of positioning the flap 10 in relation to the fabric part 6. In this case, the folding plate 22 is withdrawn by means of the cylinder 29 and the fabric part 6 is aligned as was described above. The flap 10 is then aligned in its sewn-on position, which is rotated by 180° in relation to its finished position of use, at the fabric part 6 at two light marks emitted by two light radiators 33, taking into account the course of the pattern, and is sectioned by a vacuum chamber 34 over a perforated plate 35. In the next step, the folding plate 22 is again withdrawn into its starting position, and the pocket cut 8 is positioned as was likewise described above. Instead of the light marks, it is also possible to use a movable stop 100, at which the flap 10 is positioned and then moved out of the folding area of the folding device 32.
As is shown in FIG. 6, the sewing machine 3 comprises, in the usual design, a base plate 36 having a cylinder arm design and an upper arm 37, in which an arm shaft 38 is mounted, which is driven by an electronically controlled motor 39. The drive of the needle bar 40 with the needle 41 and also the drive of a hook 42 located in the base plate 36 are derived from the arm shaft 38 in the usual manner. A thread 45 is fed to the needle 41 via a thread take-up lever 43 and a thread tensioner 44, and the thread is gripped by the shuttle 42 when the needle 41 dips into the base plate 36 through a stitch hole 46 and is connected to a lower thread, not shown, to form a double-thread lock stitch.
Above the fabric support plate 5 (FIG. 1 and FIG. 6), a fabric guide means 4, which is arranged behind the sewing machine 3 when viewed from the operator's side 47, is provided for the fabric parts 6, 8, 10 to be sewn together. It has a guide rail 48, which is rigidly connected to the frame 1 above the fabric support plate 5. A guide carriage 49 is driven on the guide rail 48 in the X direction via a toothed belt 50 by a computer-controlled motor (not shown here). The guide rail 51, on which the guide carriage 52 is moved in the Y direction by a computer-controlled motor (not shown here) via a toothed belt 53, is rigidly connected to the guide carriage 49 for the movement in the X direction. The guide rail 48 with the guide carriage 49 for the movement in the X direction and the guide rail 51 with the guide carriage 52 for the movement in the Y direction form a mobile rectangular system of coordinates, with which any amount of travel can be performed in the known manner by means of a computer-controlled program (CNC) with the control unit 96. The Y carriage 52 is provided with a bracket 54, in which two guide rails 55 and 55' slide. The guide bars 55 and 55' are connected to the connecting support 57 to form a guide unit. This guide unit is actuated by the compressed air-controlled lifting cylinder 58, which is fastened to the bracket 54 on the one side and is connected to the connecting support 57 at its piston rod 56. A fabric holder 60 is positioned at the connecting support 57 by means of straight pins 59 and is fastened by means of screws 61, and the fabric holder is perforated by a groove 62, which corresponds to the course of the seam of the pocket contour 16 to be sewn.
To sew the flap 10 on the fabric part 6, the fabric holder 60 is equipped with a turning slide system 63, a folding slide system 64, and a flap-gripping system 65.
The turning slide system 63, see FIG. 7 and FIG. 8, comprises a turning strip 66, which is fastened to the cylinder clamping pieces 67 and 67', to which the piston rods of the cylinders or turning strip drives 68 and 68' are connected to form a displacing unit. The cylinders 68 and 68' are mounted at their end rotatably around the pin 69 in fork-shaped bearing blocks 70 and 70', which are fastened to the fabric holder 60. The exact height position of the turning strip 63 relative to the fabric support plate 5 is set by the adjusting elements 71 and 71', at which the cylinders 68 and 68' are supported. The pressing systems 72 and 72', which press down the entire set turning slide system 63 against the adjusting elements 71 and 71' with the springs 73 and 73', on the one hand, and permit the turning strips 66 to be raised during crossing over thickened parts of the fabric, on the other hand, are arranged at the cylinders 68 and 68' on the opposite side of the pin 69. The spring pressure of the pressing system 72 and 72' is transmitted to the cylinders 68 and 68' via the bolt 74. To increase the action of the pressing force, the bolt 74 may be designed as a piston, and controlled compressed air may be admitted to the spring chamber 75 via the inlet 76. The turning strip 66 is provided with a slot 77 for sewing the cover seam 13 and is provided with a tapering chamfer 79 along the turning edge 78 to improve movement under the pocket flap 10 and the subsequent turning around the folding strip 80.
The folding slide system 64 has a design similar to that of the turning slide system 63. The folding strip 80 is fastened to the cylinder clamping pieces 81 and 81', which are in turn connected to the piston rods of the cylinders or folding strip drive means 82 and 82' to form one unit. The cylinders 82 and 82' are fastened to the fabric holder 60 similarly to the fastening of the turning slide system via the fork-shaped bearing blocks 83 and 83', in which the cylinders are mounted rotatably. The pressing systems 84 and 84' press the cylinders 82 and 82' against the adjusting elements 85 and 85', which are set such that the necessary pressing pressure for sewing the fastening seam 12 is brought about when the folding strip 80 is placed on the flap 10.
The flap-gripping system 65 (FIG. 1, FIG. 6a and FIG. 6b) comprises a guide housing 88, in which two needle bars 86 and 86' moving in opposite directions are actuated by the needle cylinders 89 and 89'. Due to the alternating actuation of the cylinders 89 and 89', the needle bars 86 and 86' are displaced in the downward direction according to the known principle and penetrate with the needles 87 into the fabric of the flap 10 in the process to pick this up as a part of the fabric holder 60.
Instead of the needle gripper, it is also possible to use a vacuum gripper, which does not leave behind any damage on the fabric during the processing of delicate fabrics.
The guide housing 88 is moved up and down in a slot in the fabric holder 60 by the fabric holder cylinder 90, which is fastened to the fabric holder 60 via the cylinder holder 91. Two fabric holder rods 92 and 92', which extend under the cylinders 68, 68', 82 and 82' and raise same when the fabric holder 60 is placed on the folding plate 22 in the loading station 2 and during the return of the folding plate 22 from the folding position, so that a soft, trouble-free process is guaranteed during the transfer of the fabric parts to be sewn from the loading station 2 to the sewing machine 3, are fastened to the guide housing 88. To protect the needles from damage in the extended position in the loading position 2, the flap support surface 25 is provided with a groove 106 (FIG. 2), into which the needle tips passing through can penetrate.
The mode of operation is as follows:
A fabric part 6, here a shirt front part, is placed on the fabric support plate 5 under the folding device of the loading station 2 (FIG. 1 and FIG. 2) and is aligned at the line marks 7 and 7' as was described above, while the folding plate 22 is in an extended position brought about by the folding plate cylinder 29 above the fabric part 6. The pocket cut 8 is then placed on the folding plate 22 and pushed against the stop 23 and is positioned there according to the pattern and is held at the same time by means of the clamps 24 and 24'. The flap 10 is placed on the positioning surface 25 in the same manner, is pushed into the sew-on position against the stop 26, and is aligned according to the pattern, as a result of which it is held by the clamps 28 and 28' at the same time.
The pocket cut 8 is then folded by means of folding tools 32, which are shown only partially, i.e., its edge 19 is folded over on the underside of the folding plate 22. The folding plate 22 is subsequently lowered together with the folding tools 32 shown only partially onto the fabric part 6 located on the fabric support plate 5. The folding tools 32 are separated from the folding plate 22 and are pivoted upward as a whole with the folding tool support 31 and moved away to the rear. With the exception of the placement of the positioning surface 25 and the flap 10 in a rotated sew-on position and of the rough closing edge on the folding plate 22, this procedure has been known from the above-mentioned DE 37 09 251 A1 (corresponding to U.S. Pat. No. 4,813,362), DE 37 09 251 A1 (corresponding to U.S. Pat. No. 4,785,749) and DE 37 09 210 A1 (corresponding to U.S. Pat. No. 4,793,272), which may thus be referred to.
The fabric holder 60 (FIG. 1, FIG. 2, FIG. 6a and FIG. 6b) with the turning slide system 63 arranged on it, with the folding slide system 64 and the flap-gripping system 65 is moved into the loading station 2, located on the left in FIG. 1, in the raised position (with the cylinders 58 and 90 withdrawn) via the guide carriages 49 (for the X axis) and 52 (for the Y axis) with the associated toothed belts 50 and 53 by means of computer-controlled motors (not shown here) for the X and Y axes. In this position, in which the slot 62 assumes an exact position relative to the folded pocket 9, the fabric holder 60 is lowered onto the folding plate 22 by reversing the movement of the cylinder 58, and the folded pocket 9 with the fabric part 6 is pressed against the fabric support plate 5. The movement of the cylinder 90 for the flap-gripping system 65 is then reversed, and it lowers the turning strip 66 and the folding strip 80 onto the support surface 20 and the guide housing 88 with the needle bars 86 and 86' onto the flap 10. The cylinders 89 and 89' are actuated in this position, as a result of which the needle bars 86 and 86' with the needles 87 are extended, and they penetrate into the flap 10. By reversing the movement of the cylinder 90 again (cylinder 90 withdrawn), the flap 10 gripped with the needle bars 86 and 86' is raised from the positioning surface 25, as the turning strip 66 and the folding strip 80 are also raised from the support surface 20 via the rods 92 and 92'. The folding plate 22, which is under the pressure of the fabric holder 60 and presses the folded pocket 9 with the fabric part 6 against the fabric support plate 5, is then pulled out under the fabric holder 60 together with the support surfaces 20 and 25 and the clamps 24, 24' and 28, 28' by reversing the movement of the cylinder 29, and the folded pocket 9 and the flap 10 remain in a fixed position relative to the fabric part 6 in their above-described sew-on position. The fabric holder 60 with the three fabric parts 6, 9 and 10 is subsequently transferred from the loading station 2 to the sewing machine 3 by means of the fabric guide system 4, and the movement of the cylinder 90 of the flap-gripping system is again reversed during this movement, and it lowers the gripped flap 10 with the needle bars 86 and 86' onto the fabric part 6 and holds it non-displaceably in the predetermined sew-on position. The turning strip 66 and the folding strip 80 are also lowered to the level predetermined by the adjusting elements 71, 71' and 85, 85' by reversing the movement of the cylinder 90. The seam 16, by means of which the folded pocket 9 is connected to the fabric part 6, is then sewn in the usual manner.
After this sewing process, the fabric parts 6, 9 and 10 are pushed by means of the fabric holder 60 over the vacuum chamber 93 of the fabric-holding means 98. By correspondingly admitting vacuum to the vacuum chamber 93, the three fabric parts 6, 9 and 10 are suctioned over the perforated plate 94 and are held in a fixed position on the fabric support plate 5. The movement of the cylinders 89 and 89' is reversed in this position, so that the needle bars 86 and 86' release the flap 10, and the fabric holder 60 is raised by reversing the movement of the cylinder 58.
The fabric holder 60 is moved from this raised position from the pocket sew-on position into the flap sew-on position by a corresponding drive of the Y carriage 52 by a predetermined amount Y1 in the negative Y direction, so that the folding edge 95 of the folding slide 80 comes down in the vicinity of the fastening seam 12 after the lowering of the fabric holder 60 onto the fabric parts 6, 9 and 10 and presses the flap 10 down against the fabric support plate 5 for sewing the fastening seam 12 (FIG. 7 and FIG. 8).
The turning strip 66 is extended at this point in time at the latest into the position shown in FIGS. 7 and 8 by reversing the movement of the turning slide cylinders 68 and 68'. The sewing of the fastening seam 12, whose course can be freely selected, e.g., with a seam interruption for a pencil opening 101 (FIG. 5b), is performed thereafter.
After the fastening seam 12 has been prepared, the movement of the turning slide cylinders 68 and 68' is reversed, and these cylinders move the turning strip 66 under the flap 10 to the fastening seam 12, which is located in the immediate vicinity of the folding strip 80. The turning strip 66 and thus also the flap 10 are raised during this movement (FIG. 9 and FIG. 10) approximately to the level of the folding strip 80 by slightly tilting the angle of the cylinders 68 and 68' in relation to the fabric support plate 5.
At the fastening seam 12, the turning strip 66, which continues to move toward its end position, abuts the folding strip 80, with which it comes into contact, and it rotates the flap 10 by 180° around the fastening seam 12 and the folding edge 95 of the folding strip 80 into its final position of use 11. Due to the folding strip 80 being in the immediate vicinity of the fastening seam 12, an exact rotation and consequently also folding of the flap 10 around the folding edge 95 into its position of use 11 by means of the turning strip 66 is guaranteed with all fabric grades.
After the turning strip 66 has reached its new end position, the movement of the folding slide cylinders 82 and 82' is reversed, and the folding strip 80 is withdrawn into its new end position, as is shown in FIGS. 11 and 12, and it releases the flap 11 for sewing the cover seam 13. After the folding strip 80 has reached its new position, the turning strip 66 presses the flap 11 against the fabric support plate 5 by means of the pressing systems 72 and 72'. In this state, the flap is connected in its position of use 11 to the fabric part 6 through the slot 77 of the turning strip by means of the cover seam 13.
After the conclusion of this sewing process, the fabric holder 60 is raised by reversing the movement of the cylinder 58, and the Y carriage 52 is displaced by a section Y2 to the extent that the folding strip 80 is no longer covered by the flap 11. The unstacking of the fabric parts 6, 9 and 11 sewn together, which will begin thereafter, can thus take place in a trouble-free manner. During the sewing process, which takes place automatically, the operator can again place new fabric parts into the preparation station 2 in the above-described manner. These new fabric parts will be sewn after the finished, sewn fabric parts 6, 9 and 11 have been unstacked and the fabric holder 60 has been returned into the loading position 2.
The sewing on of pocket flaps with two cover seams is also performed in practice for design reasons. This variant (FIG. 5b) can also be carried out with the above-described device. The flap 10 is rotated now into its position of use 11 around the folding strip 80, without sewing the fastening seam 12, and is subsequently sewn to the fabric part 6 with two cover seams 13 and 21, as is shown in FIG. 11. The course of these seams may be freely selected, e.g., with a seam interruption 101 for a pencil opening.
To hold the fabric parts 6, 9 and 10 in the fabric-holding means 98, a needle bar 99 may also be used during the transfer of the fabric holder 60 from the pocket sew-on position into the flap sew-on position, wherein the needle bar 99 penetrates into the fabric of these fabric parts due to actuation of the cylinder or needle drive 107 via the perforated plate 94 and holds these fabric parts in a fixed position on the fabric support plate 5.
As an alternative, this process and this automatic sewing machine may also be used to sew on flaps on clothes in the manner described here, which have no pockets for reasons of fashion or on which the pockets must be sewn on according to another manufacturing process for manufacturing technical reasons.
All drives, motors and cylinders with the solenoid valves associated with them are actuated via a programmable control 96.
The features described in specification, drawings, abstract, and claims, can be used individually and in arbitrary combinations for practicing the present invention.
While specific embodiments of the invention have been shown and described in detail to illustrate the application of the principles of the invention, it will be understood that the invention may be embodied otherwise without departing from such principles. | A preparation station including a fabric support plate, a folding plate and a positioning support for a flap of a flap pocket. The fabric part to which the pocket is to be connected, is supported by the fabric support plate. The flap, and possibly the pocket cut are lined at the preparation station. The pocket cut can also be placed into its folded position by the preparation station. The fabric part, with the pocket cut, if present, and the pocket flap are then moved by a fabric holder to a sewing machine with a sewing position. There, the pocket cut can be sewn onto the fabric part if desired. The pocket flap is in a rotated position, which is angularly spaced by approximately 180° from a final position of the pocket flap. The pocket flap can then be connected to the fabric part by a fastening seam. A turning strip turns over the flap, in cooperation with a folding strip, and another seam connects the flap to the fabric part in its final position. In another embodiment, the folding strip can hold the rough cut end of the pocket flap against the fabric part, and the turning strip turns the remainder of the flap into the final position, where the flap is connected to the fabric part by one or two seams. | 3 |
TECHNICAL FIELD
The present invention relates to a thermoplastic polyester resin composition, and more particularly to a thermoplastic polyester resin composition wherein a modified polyolefin elastomer is used as a modifier.
BACKGROUND ART
When compared with other industrial materials such as glass, metals, wood, concrete, thermoplastic polyester resin compositions have various features such as inexpensiveness lightness, high specific strength, high chemical stability, high moldability. and therefore they are widely used for industrial products, domestic utensils and parts of both.
Under the recent development of industry and technology, various techniques have been developed and studied to improve the properties and qualities of the compositions by reinforcement means with glass fibers or filers and/or various polymer alloy technologies.
Polyethylene terephthalate (hereinafter referred to as ‘PET’), a kind of thermoplastic polyester resin, is superior in heat resistance, chemical resistance, mechanical characteristics and electric characteristics, additionally transparency and barrier ability whereby it is widely used for bottles and packaging material for food.
However, one of the shortcomings of PET is inferiority in impact resistance, and thereby the uses of PET as a material for injection molding is markedly limited. In fact, only glass fiber reinforced materials are practically used as a material for injection molding.
Therefore, improvement of PET's properties by inexpensive and easy means is expected in order to overcome the limited uses of PET as a molding material. If such techniques are developed, the uses of thermoplastic polyester resin will be widened to electric home appliances, construction materials, automobile parts and the like.
Another problem is that a large number of various PET bottles being dumped by industries etc. have few uses for recycling due to the reasons mentioned above, although it is possible to collect them.
In particular, it is a big problem that recycled PET bottles have few uses, although collecting the bottles is easy and safe, and the bottles are high in purity as a raw material since they are originally vessels for drinks and the like.
DISCLOSURE OF THE INVENTION
The present invention has been intended to achieve the above-mentioned purposes.
The inventors of the present invention developed a carboxyl-modified metallocene catalyzed polyolefin elastomer (polyolefin elastomer polymerized by using a metallocene catalyst) and a glycidyl methacrylate adduct to the elastomer for inexpensive and easily manufacturable modifier of a thermoplastic polyester resin, and thereby developed a novel thermoplastic polyester resin which is superior in impact resistance.
The present invention thus increases the uses for recycled thermoplastic polyester resins.
Additionally, the inventors succeeded in developing a thermoplastic polyester resin wherein inorganic fillers are mixed.
The present invention is embodied in accordance with the following constitutions and particulars.
The invention according to Claim 1 is a thermoplastic polyester resin composition comprising 90 to 60 parts by weight of a thermoplastic polyester resin and 10 to 40 parts by weight of a carboxyl-modified metallocene catalyzed polyolefin elastomer.
The above-mentioned composition improves a thermoplastic polyester resin markedly in its mechanical characteristics.
The invention according to Claim 2 is the thermoplastic polyester resin composition according to Claim 1 , wherein the aforementioned thermoplastic polyester resin is polyethylene terephthalate.
The above-mentioned composition provides a highly impact-resistant thermoplastic polyester resin composition, wherein polyethylene terephthalate, which is frequently used for PET bottles, is the main material.
The invention according to Claim 3 is the thermoplastic polyester resin composition according to Claim 2 wherein the aforementioned metallocene catalyzed polyolefin elastomer is ethylene.α-olefin copolymer hating 5 to 30 wt. %, based on the weight of the ethylene, of α-olefin comonomer and the basic structure (repeating unit) of the elastomer is [CH 2 —CH 2 ] n .[CH 2 —CHR] m (R is a side chain represented in CH 3 .[CH 2 ] L , L is 3 to 8 inclusive.).
The above-mentioned composition improves impact resistance of a thermoplastic polyester resin since the elastomer comprises the side chains with an appropriate length. Moreover, appropriate flexibility of the resins is attained.
The invention according to Claim 4 is a filled (inorganic-filler-mixed) thermoplastic polyester resin composition comprising 100 parts by weight of the thermoplastic polyester resin composition according to Claims 3 and 10 to 500 parts by weight of an inorganic filler.
The above-mentioned composition improves a thermoplastic polyester resin composition markedly in its mechanical strength, such as its flexural modulus, by the action of the inorganic or mineral filler. In addition, the mixing of a thermoplastic polyester resin composition and an inorganic filler is rendered easy and uniform since the mixing ratio of the composition and the filler is appropriate. Furthermore, the polyolefin elastomer is improved in interfacial contact with the inorganic filler and thereby retains even more preferable mechanical characteristics since the whole elastomer is modified with an acid uniformly.
The invention according to Claim 5 is the thermoplastic polyester resin composition according to Claim 4 , wherein a carboxyl-modified metallocene catalyzed polyolefin elastomer is modified with 0.01 to 1.0 wt. %, based on the weight of the elastomer, of maleic anhydride or maleic acid.
The above-mentioned composition enables the whole metallocene catalyzed polyolefin elastomer to be uniformly modified with an acid under the limited conditions, and therefore the elastomer is improved in the bonding with a thermoplastic polyester resin and inorganic fillers. In addition, with the use of a twin-screw extruder, it is possible to facilitate the acid modification of the polyolefin elastomer and the mixing of the elastomer with a thermoplastic polyester resin and additionally an inorganic filler.
The inventions according to Claims 6 to 8 are the inventions wherein the invention according to Claim 2 is combined with the inventions according to Claims 4 and/or 5 .
The invention according to Claim 9 is the thermoplastic polyester resin composition according to Claim 1 , wherein the aforementioned thermoplastic polyester resin is a mixture of polyethylene terephthalate and polybutylene terephthalate at a weight ratio of from 95:5 to 5:95.
The above-mentioned composition provides a highly impact-resistant thermoplastic polyester resin composition, wherein the main material is the mixture of polyethylene terephthalate and polybutylene terephthalate at a wide range of weight ratios of from 95:5 to 5:95 in consideration of flowability, moldability and heat resistance depending on its uses.
The inventions according to Claims 10 to 15 are the inventions according to Claims 3 to 8 , wherein the mixture of polyethylene terephthalate and polybutylene terephthalate is used in place of the polyethylene terephthalate in the inventions according to Claims 3 to 8 , in correspondence to the difference between the invention according to Claim 9 and the invention according to Claim 2 .
The invention according to Claim 16 is a thermoplastic polyester resin composition comprising 90 to 60 parts by weight of a thermoplastic polyester resin and 10 to 40 parts by weight of a glycidyl methacrylate adduct to a metallocene catalyzed polyolefin elastomer.
The above-mentioned composition provides a highly impact-resistant thermoplastic polyester resin composition comprising 90 to 60 parts by weight of thermoplastic polyester resin and 10 to 40 parts by weight of the glycidyl methacrylate adduct to a metallocene catalyzed polyolefin elastomer which is excellent in impact resistance.
The inventions according to Claims 17 to 30 are the inventions according to Claims 2 to 15 , wherein the glycidyl methacrylate adduct is used in place of a carboxyl-modified metallocene catalyzed polyolefin elastomer in the inventions according to Claims 2 to 15 in correspondence to the difference between the invention according to Claim 16 and the invention according to Claim 1 .
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an example of a metallocene catalyst.
FIG. 2 is an example of aluminoxane compound which is used in combination with a metallocene compound as a composite catalyst.
FIG. 3 is another example of a metallocene catalyst, an example of a composite catalyst.
FIG. 4 is a graph showing the difference in molecular-weight distribution between a polyolefin elastomer polymerized by using a metallocene catalyst (single-site catalyst) and a polyolefin elastomer polymerized by using a conventional catalyst.
FIG. 5 is a graph showing the difference in DSC-method melting point and density between a polyolefin elastomer polymerized by using a metallocene catalyst (single-site catalyst) and a polyolefin elastomer polymerized by using a conventional catalyst.
FIG. 6 is an example of the chemical structures of a geometrically constrained catalyst.
FIG. 7 is a model view showing a main chain having long branched chains with a length close to the main chain in a metallocene catalyzed polyolefin elastomer.
FIG. 8 is a view showing the basic structure of a main chain in a metallocene catalyzed polyolefin elastomer.
FIG. 9 is a schematic view showing the acid modification of a metallocene catalyzed polyolefin elastomer and the glycidyl methacrylate addition to the elastomer and the production of a thermoplastic polyester resin composition with the use of a twin-screw kneader.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The presuppositional techniques and equipment for carrying out the present invention are described in the following details.
Metallocene Catalyst
The metallocene catalyst herein is a catalyst wherein the qualities of the coexistent active sites are uniform. The catalyst is a compound which holds a transition metal between unsaturated cyclic compounds in the chemical structure (metallocene), and therefore called a metallocene catalyst or a single-site catalyst. Since active sites with different qualities do not coexist in the catalyst, it is possible to produce a uniform polymer with a small distribution of molecular weight and a polymer with an arbitrary regularity corresponding to the symmetry of ligand.
Specifically, the catalyst has a structure as shown in FIG. 1 .
The catalyst in FIG. 1 is called a metallocene complex. A composite catalyst wherein the metallocene complex shown in FIG. 1 is combined with the compound shown in FIG. 2 (aluminoxane) can also be listed.
In FIG. 1, M 1 is Ti, Zr, Hf, V, Nb or Ta. R 1 and R 2 may be the same as or different from each other, and represent hydrogen atom halogen atom. an alkyl group having 1 to 10C (carbon atom). an alkoxyl group having 1 to 10C, an aryl group having 6 to 10C, an alkenyl group having 6 to 10C, an alkenyl group having 2 to 10C, an arylalkyl group having 7 to 40C, an alkylaryl group having 7 to 40C or an arylalkenyl group having 8 to 40C. R 3 and R 4 are the same as or different from each other, and represent a residual group of mononuclear or polynuclear hydrocarbon which can form a complex having a sandwich structure with central metal atom M 1 .
R 5 is ═BR 6 , ═AIR 6 , —Ge—, —Sn—, —O—, —S—, ═SO, ═SO 2 , ═NR 6 , ═CO, ═PR 6 or P(O)R 6 (wherein R 6 is hydrogen atom or halogen atom.). In FIG. 2, R 11 to R 15 may be the same as or different from each other, and represents 1 to 6C alkyl group, 1 to 6C fluoroalkyl group. 6 to 18C aryl group, 6 to 18C fluoroaryl group or hydrogen atom. a is an integer of 0 to 50 inclusive.
FIG. 3 shows an example of a composite catalyst comprising the compounds shown in FIGS. 1 and 2. The details of the catalyst will not be given herein since the catalyst is a publicly known art which is disclosed. for example, in PACKPIA , No. 4. pp.12-53, 1994, as well as in Japanese Unexamined Patent Publications No. 5-140227, No. 5-140228, No. 5-209019 and the like.
A Metallocene Catalyzed Polyolefin Elastomer
A metallocene catalyzed polyolefin elastomer polymerized by using the above-mentioned metallocene catalyst has a distinct melting point and glass transition temperature as well as no tackiness because of a narrow molecular weightdistribution, homogeneity and even molecular weight as shown in the molecular-weight distribution graph (FIG. 4 ).
In the figures, the multisite catalyst is a conventional catalyst. FIG. 5 shows how the DSC-method melting point and density differ in both catalysts. The metallocene catalyzed polyolefin elastomer. which is essential to the present invention, comprises 5 to 30 wt. % of α-olefin comonomer to ethylene and the side chains with 6C in Examples. In the present state of the art (at the time of the application), the elastomer is produced by using a geometrically constrained catalyst among the metallocene catalysts. A geometrically constrained catalyst is a coordination metal complex in which a metal atom or ion is bonded to a delocalized substitution π bond site to form a constrained geometry around the metal atom or ion. More particularly, it is a composite catalyst as shown in FIG. 3, wherein a compound having cyclopentadiene molecules as the ligand (zirconocene dichloride), which is shown on the left side in FIG. 3, is combined with an aluminoxane compound, which is shown on the right side in FIG. 3 .
Another example is shown in FIG. 6 .
The more detailed description of the catalyst will not be given herein since the catalyst is a publicly known art which is disclosed on pp. 10 of JAPAN PLASTICS , No. 2, Vol. 47, as well as Japanese Unexamined Patent Publications No. 7-500622, No. 7-53618, etc.
A polyolefin elastomer produced by using the geometrically constrained catalyst has high moldability in addition to the general characteristics particular to a polyolefin elastomer produced by using a metallocene catalyst, because long branched chains are selectively introduced to a main chain. The model constitution is shown in FIG. 7 and the basic structure of the main chain is shown in FIG. 8 . As shown in FIG. 8, the side chain has 6C.
In Japan, the polyolefin elastomer is commercially available from Du Pont Dow Elastomer, Inc. under the trade name of ENGAGE. The physical property values of ENGAGE 8200, a kind among the various kinds of ENGAGEs with the grades for general uses (the density is 0.885 to 0.870 g/cc ) are roughly as follows:
The density is 0.87 g/cc, the ratio of comonomer is 24 wt. %, the melt index is 5 (g/10 min.), the tensile strength is 72 kg/cm 2 , the 100% tensile modulus is 22 kg/cm 2 , the extensibility is 980%, the shore hardness is 75 (A) and 26 (D), the DSC melting point (peak) is 68° C.
Various kinds of ENGAGEs with high density grade (0.895 to 0.910 g/cc) are also available. The more detailed description of the polyolefin elastomer will not be given herein since the polyolefin elastomer is a publicly known art disclosed not only in the catalogs of the corporation but also on pp. 76-77 Polyfile , August 1996, etc.
The Acid Modification of a Polyolefin Elastomer
It has been well known for long that, by modifying polypropylene, polyethylene, ethylene propylene rubber (EPR), ethylene propylene diene methylene (EPDXI) and the like with an acid, polar groups are added to those matters, and the compatibility of those matters with nylon etc. is thus improved.
However, it has been considered that the metallocene catalyzed polyolefin elastomer can not be modified with an acid since the bridges are easily caused by the action of peroxides or the irradiation of radioactive rays. The elastomer can not therefore be used as a modifier for PET and the like (impact modifier) and its uses have been limited in the uses with polyolefin-based plastics in consideration of compatibility.
Nevertheless, the inventors succeeded in modifying the elastomer with an acid under the limited conditions detailed below and thus completed to produce a thermoplastic polyester resin with far higher impact resistance than that of conventional materials by mixing the resin with the modified elastomer.
Maleic acid, acrylic acid. methacrylic acid. fumaric acid, itaconic acid, citraconic acid and anhydrides of these acids are among the acids usable for the acid modification of the polyolefin elastomer. Among them, maleic anhydride is preferable because of its two functional groups and inexpensiveness. The reason why the anhydride is preferable is that the monomer reactivity is high and the grafting is easy in view of steric hindrance, polar factor and the like.
An organic peroxide which decomposes at an appropriate speed at the melting temperature of the elastomer are used as an initiator for the grafting Lauroyl peroxide, di-tert-butyl peroxide, 1,3-bis (t-butylperoxyisopropyl) benzene, benzoyl peroxide, tert-butyl perbenzoate, dicumyl peroxide or the like are used as the organic peroxide.
The process of acid modification of a polyolefin-based elastomer is described below.
Single screw extruders, twin-screw extruders, kneaders and the like are usable for the process. Among them, a twin-screw extruder equipped with a kneading mechanism such as rotor type kneading segments or kneading discs as shown in FIG. 9 is preferable. In FIG. 9, the twin-screw extruder comprises an upper feeding port ( 1 ), a downstream feeding port ( 2 ), rotor type kneading segments ( 3 ) and kneading discs ( 4 ). Only the upper feeding port ( 1 ) is used herein. After the inside of the extruder's cylinder is heated to the temperature at which the polyolefin elastomer can melt and the organic peroxide can act, pellets of the elastomer, maleic anhydride and organic peroxide, each with a predetermined quantity, or the prepared mixture of the aforementioned three matters each with a predetermined quantity is consecutively provided into the upper feeding port of the extruder through the hopper. The quantity of the maleic anhydride is 0.01 to 1.0 wt. % to the elastomer, preferably 0.05 to 0.2 wt. % to the elastomer. The reason is that less quantity of the maleic anhydride than the above range results in insufficient compatibility, while more quantity results in such undesirable phenomena that the effect of the compatibility improvement reaches its limit, the bridges of molecules occur and the elastomer can not be uniformly dispersed and mixed in a thermoplastic polyester resin, flowability in molding is hindered and the appearance of molded products is spoiled.
The examples described later will detail the significant effects of the acidmodified polyolefin elastomer thus produced to the present invention.
The Adding of Glycidyl Methacrylate to a Polyolefin Elastomer
The process of the addition of glycidyl methacrylate to a polyolefin elastomer, which is another constituent in the present invention, is described below.
The preferable equipment for this process is the same as used in the above-mentioned acid modification. likewise only the upper feeding port ( 1 ) is used.
After the inside of the extruder's cylinder is heated to the temperature at which the polyolefin elastomer can melt and the organic peroxide can act, the prepared mixture comprising pellets of the elastomer, glycidyl methacrylate and organic peroxide, each with a predetermined quantity, is consecutively provided into the upper feeding port of the extruder through the hopper. The quantity of the glycidyl methacrylate is 0.01 to 1.0 wt. % to the elastomer, preferably 0.05 to 0.2 wt. % to the elastomer. The reason is that less quantity of the glycidyl methacrylate than the above range results in insufficient compatibility, while more quantity results in such undesirable phenomena that the effect of the compatibility improvement reaches its limit, the bridges of molecules occur and the elastomer can not be uniformly dispersed and mixed in the thermoplastic polyester resin, flowability in molding is hindered and the appearance of molded products is spoiled.
The examples described later will detail the significant effects of the glycidyl-methacrylate-added polyolefin elastomer thus produced to the present invention.
A Thermoplastic Polyester Resin
In view of waste disposal, it is preferable that the pulverized materials derived from used PET bottles are employed as a thermoplastic polyester resin for a main material of a thermoplastic polyester resin composition, although the pulverized materials have various weight ratios of polyethylene terephthalate and polybutylene terephthalate.
Inorganic Fillers
It is preferable that inorganic fillers are surface-treated beforehand by 0.01 to 0.5 wt. % of silane coupling agent, or stearic acid or metallic salt of the acid is uniformly applied onto the surface in order to further improve the interfacial adhesion of the inorganic fillers to a carboxyl-modified polyolefin elastomer. The materials are 0.1 to 10 l in particle size of calcium carbonate, talc, mica, silica, kaolin, clay, wollastonite, potassium titanate, barium sulfate, magnesium hydrate or glass beads and the like. Generally, 10 to 200 parts by weight, preferably 50 to 200 parts by weight, of the inorganic fillers is mixed with 100 parts by weight of a thermoplastic polyester resin.
Iron powder, copper powder or brass powder is used to obtain molded products with a high specific gravity, and ferrite is used for plastic magnets. In these cases, 100 to 500 parts by weight of the inorganic fillers is mixed with 100 parts by weight of a thermoplastic polyester resin.
The Producing and Kneading of a Thermoplastic Polyester Resin Composition
A thermoplastic polyester resin composition of the present invention can be produced by melting and kneading the mixture of polyester resin powder and a polyolefin elastomer modified with a carboxylic acid with the use of extruders. The composition can be easily produced by using an ordinary single or twin-screw extruder. A single screw extruder is often equipped with Dulmage type kneading screws and barrier flight (Maddock) type screws in order to reinforce the effect of kneading, and such extruders may also be used.
As a process to effectively produce a thermoplastic polyester resin composition of the present invention, it is possible to employ the method of modifying a polyolefin elastomer with an acid by using a twin-screw extruder and providing a the thermoplastic polyester resin into the second material feeding port placed at the midstream of the same extruder. In this method, it is preferable to install rotor type kneading segments or disc type kneading blocks in the second step. In this case, maleic anhydride and organic peroxide are entirely exhausted in the upper part of the extruder, and therefore they do not give any bad effects to polyethylene terephthalate.
The melting and kneading are normally carried out at a temperature of around 260° C.
EXAMPLES
A thermoplastic polyester resin composition of the present invention is illustrated by the following examples.
Raw Materials
Thermoplastic Polyester Resin
Pulverized flakes of used PET bottles manufactured by With PET Bottle Recycle, Inc.
Metallocene Catalyzed Polyolefin Elastomer (POE)
ENGAGE 8200 manufactured by Du Pont Dow Elastomer, Inc.
As found in FIG. 5, a DSC-method melting point of ENGAGEs can be selected within a certain range corresponding to the matter compatible with it. ENGAGE 8200 was used in the examples herein.
In the examples, the conditions were as follows.
1. Acid Modification of POE
100 parts by weight of polyolefin elastomer ENGAGE 8200, 0.2 parts by weight of maleic anhydride (pulverized below 1 mm) and 0.1 parts by weight of 1,3-bis(t-butylperoxyisopropyl)benzene were mixed uniformly by a drum blender.
2. Adding of Glycidyl Methacrylate to POE
(1) 100 parts by weight of polyolefin elastomer: ENGAGE 8200, 0.2 parts by weight of glycidyl methacrylate: Blenmer G manufactured by Nippon Oil & Fats, Inc. and 0.1 parts by weight of di-tert-butyl peroxide were mixed uniformly by a drum blender.
(2) 100 parts by weight of polyolefin elastomer: ENGAGE 8200, 0.4 parts by weight of glycidyl methacrylate: Blenmer G manufactured by Nippon Oil & Fats, Inc. and 0.1 parts by weight of di-tert-butyl peroxide were mixed uniformly by a drum blender.
3. Extruding
A twin-screw extruder, NRII-46 mmSG manufactured by Freesia Macross, Inc., was used.
The constitution was as follows.
L/D=40 in total, and starting from the hopper, the constitution was;
(1) 18 D of feeding and melting section
(2) 6 D of rotor type kneading segments
(3) 4 D of feeding section
(A second feeding port is placed here. However, it was not used in the examples.)
(4) 4 D of kneading discs
(5) 8 D of discharge section
(A vent hole is provided at the position of 2 D in this zone, and the zone is degassed with a vacuum pump.).
Cylinder temperature
200° C.
Screw rotation
150 RPM
Throughput
50 kg/hr.
The above-mentioned mixtures were melted, kneaded and extruded according to the conditions set forth above.
The extruded article in the above 1 is hereinafter referred to as ‘M-POE-0.2’, likewise, the article in the above 2 (1) as ‘G-POE-0.2’ and the article in the above 2 (2) as ‘G-POE-0.4’.
4. Producing a Thermoplastic Polyester Resin Composition with Mixing
The compositions of the present invention were produced under the conditions below with the use of the same extruder as above.
Cylinder temperature
250° C.
Screw rotation
200 RPM
Throughput
60 kg/hr
Melting, kneading and extruding were carried out according to the conditions set forth above.
5. Testing
Injection molding machine
J75E11 manufactured by Japan Steel Works,
Inc.
Cylinder temperature 250° C.
Mold
The specimens for ASTM D638 Tensile Test
and the specimens for ASTM D790 Flexural
Test were molded in a set.
Mold temperature 80° C.
The test results of the mechanical characteristics of thus produced test specimens are shown in Table 1 and 2.
In these tables, PET represents thermoplastic polyester resin, POE represents polyolefin elastomer, M-POE-0.2 represents polyolefin elastomer modified with a carboxylic acid, G-POE-0.2 represents the adduct of 0.2 wt. % of glycidyl methacrylate to polyolefin elastomer and G-POE-0.4 represents the adduct of 0.4 wt. % of glycidyl methacrylate to polyolefin elastomer. In Comparative Example 1, the value 100 on the line of PET shows that PET is 100 wt. %, and in the Comparative Example 2, 80 on PET and 20 on POE shows that PET is 80 wt. % and POE is 20 wt. %. It is to be understood that the numbers in the other examples represent likewise.
The Izod impact strength values were improved little in Comparative Examples 2 and 3 wherein 20 or 30 wt. % of conventional POE is mixed. However, the Izod impact strength values were improved markedly in Examples 1 to 7 wherein 10 or 20 wt. % of the carboxyl-modified POE (M-POE-0.2) or the glycidyl methacrylate adduct to POE (G-POE-0.2, G-POE-0.4) was used, and in particular, over 80 kgf ·cm/cm of the values, which is the highest strength of impact resistance among plastic materials, were obtained in the Examples wherein 30 wt. % of the modified POE was mixed. Furthermore, the flexural strengths and flexural moduli were also sufficient values for structural members, and thereby the effect of the present invention was demonstrated.
In regard to the mixing and dispersing of fillers, the pellets produced according to the above method were observed with a microscope. Consequently, no abnormality was confirmed therein. Moreover, it was confirmed that the states of dispersing and mixing were good.
While a preferred form of the present invention has been described above, it is to be understood that the present invention is not limited thereto.
For example, other ingredients may be mixed such as pigments, dyes, heat stabilizers, antioxidants, UV stabilizers, antistatic agents, plasticizers and other polymers.
Additionally, a side chain of polyolefin elastomer may have either more than or less than 6C.
TABLE 1
Comparative
Comparative
Comparative
Example
Example
Example
Example
Example
Composition
Unit
1
2
3
1
2
PET
Wt. %
100
80
70
90
70
POE
Wt. %
20
30
M-POE-0.2
Wt. %
10
30
G-POE-0.2
Wt. %
G-POE-0.4
Wt. %
Mechanical
property
Flexural strength
Kgf/mm 2
8.8
5.0
3.9
6.7
4.5
Flexural modulus
Kgf/mm 2
252
170
135
210
150
Izod impact strength
Kgf · cm/cm 2
2.6
2.5
5.0
6.7
82.3
TABLE 2
Example
Example
Example
Example
Example
Composition
Unit
3
4
5
6
7
PET
Wt. %
80
70
90
80
70
POE
Wt. %
M-POE-0.2
Wt. %
G-POE-0.2
Wt. %
20
30
G-POE-0.4
Wt. %
10
20
30
Mechanical
property
Flexural strength
Kgf/mm 2
5.4
4.2
7.0
5.5
4.4
Flexural modulus
Kgf/mm 2
173
144
221
183
148
Izod impact strength
kgf · cm/cm 2
12.8
82.0
7.8
11.4
73.6 | The purposes of the present invention are to provide highly impact-resistant thermoplastic polyester resin inexpensively and promote the recycling of PET bottles, which are dumped as waste. To attain the purposes, a carboxyl-modified metallocene catalyzed polyolefin elastomer or a glycidyl methacrylate adduct to the elastomer is melt-blended with a thermoplastic polyester resin, particularly, the powder of recycled PET bottles. Additionally, a filler can be mixed, if necessary. | 2 |
This is a divisional of copending application Ser. No. 039,891 filed on Apr. 17, 1987 now U.S. Pat. No. 4,833,017.
BACKGROUND OF THE INVENTION
This invention relates to stretch wrap thermoplastic film, methods for forming a unitized plurality of goods, e.g., a pallet load, by application of stretch wrap film thereto and the stretch-wrapped units resulting therefrom. The invention is particularly concerned with a method of forming a thermoplastic stretch wrap film possessing a significant cling force on one surface thereof and no substantial cling force on the other surface thereof, the latter surface possessing a slide property when in contact with a like surface with relative motion therebetween due to the presence of particulate antiblock agent mechanically bonded to said surface.
The use of thermoplastic stretch wrap film for the overwrap packaging of goods and, in particular, the unitizing of pallet loads, constitutes a commercially significant application of polymer film. Overwrapping a plurality of articles to provide a unitized load can be achieved by a variety of techniques. In one procedure, the load to be wrapped is positioned upon a platform, or turntable, which is made to rotate and in so doing, to take up stretch wrap film supplied from a continuous roll. Braking tension is applied to the film roll so that the film is continuously subjected to a stretching, or tensioning, force as it wraps around the rotating load in overlapping layers. Generally, the stretch wrap film is supplied from a vertically arranged roll positioned adjacent to the rotating pallet load. Rotational speeds of from about 5 to about 50 revolutions per minute are common. At the completion of the overwrap operation, the turntable is completely stopped and the film is cut and attached to an underlying layer of film employing tack sealing, adhesive tape, spray adhesives, etc. Depending upon the width of the stretch wrap roll, the load being overlapped can be shrouded in the film while the vertically arranged film roll remains in a fixed position. Alternatively, the film roll, for example, in the case of relatively narrow film widths and relatively wide pallet loads, can be made to move in a vertical direction as the load is being overwrapped whereby a spiral wrapping effect is achieved on the packaged goods.
Some resins which have been used in the fabrication of stretch wrap film are polyethylene, polyvinyl-chloride and ethylene vinyl acetate. A fairly recent development has been the utilization of linear low density polyethylene (LLDPE) in the manufacture of stretch wrap film, e.g., as described in U.S. Pat. Nos. 4,399,180, 4,418,114 and 4,518,654, the contents of which are incorporated by reference herein. The excellent toughness and puncture resistance properties of LLDPE makes it an excellent resin for such an application. LLDPE and methods for its manufacture are described in, among others, U.S. Patent Nos. 3,645,992; 4,076,698; 4,011,382; 4,163,831; 4,205,021; 4,302,565; 4,302,566; 4,359,561; and, 4,522,987. Films fabricated from the typical LLDPE resins of commerce possess little or no cling property on either surface thereof in the absence of added cling agent.
Thermoplastic films possessing a cling property are known in the art. U.S. Pat. No. 4,311,808 describes a cling film containing a homogeneous mixture of polyisobutylene, ethylene-propylene and a low density polyethylene.
U.S. Pat. No. 4,367,256 describes a cling wrap plastic film based on a blend of high pressure low density polyethylene (HPLDPE) and LLDPE in which the latter resin represents from 5-16 weight percent of the total. In one embodiment, this film is sandwiched between two HPLDPE films.
U.S. Pat. No. 4,399,173 describes a multilayer plastic film free of melt fracture which is suitable for a variety of applications including, by implication, the stretch wrapping of goods. The film possesses a core layer of LLDPE resin of melt index 0.2-3.0 decigrams per minute and skin layers of LLDPE resin of melt index 5.0-20.0 decigrams per minute.
U.S. Pat. Nos. 4,399,180 and 4,418,114 describe a coextruded composite stretch wrap film in which an LLDPE core layer is surfaced with HPLDPE skin layers.
In the one-sided cling stretch wrap film of U.S. Pat. No. 4,518,654, layer A fabricated from a resin possessing an inherent cling property and/or a cling property resulting from the incorporation of a cling additive therein is coextruded with layer B fabricated from a resin exhibiting little if any cling, layer B exhibiting a slide property when in contrast with a layer of itself with relative motion therebetween. Layer B can contain from about 0.05 to about 2.0 weight percent of such antiblocking materials as crystalline and amorphous silicate, e.g., Na 2 O.Al 2 O 3 .SiO 2 .4H 2 O, diatomaceous earth, talc, and the like, evenly distributed therein. In each of the two working examples of this patent, layer A is an LLDPE film containing a cling additive, namely, polyisobutylene, the aforesaid synthetic sodium silicate particles being uniformly incorporated throughout layer B of the film of Example 1 and amorphous silica particles being uniformly incorporated throughout layer B of the film of Example 2. As noted in U.S. Pat. No. 4,518,654, the presence of cling on one side of the stretch wrap film but non-cling/slide properties on the other overcomes the problem of the tendency of a pallet load overwrapped with a stretch wrap film possessing cling on both of its major surfaces from destructively pulling away from a similarly overwrapped pallet load with which it is in contact when one of the pallet loads is moved relative to the other (as would be the case in the fork lift truck-handling of such overwrapped pallet loads stored in a warehouse).
U.S. Pat. No. 4,436,788 describes a stretch wrap film obtained from a mixture of 40-90 weight percent ethylene-vinyl acetate copolymer and 8-55 weight percent LLDPE.
Japanese Laid-Open Patent No. 19528/1980 describes a two-layer stretch wrap film in which a low density polyethylene layer is coextruded with a low density polyethylene layer containing from 3 to 20 weight parts of a tackifier, e.g., a polyisobutylene having a molecular weight of 200 to 300.
As previously indicated, methods of stretch wrapping articles, containers, etc., are known. U.S. Pat. No. 3,986,611 describes a tension-wrapped palletized load obtained with a stretch wrap film possessing a cling additive.
U.S. Pat. No. 4,079,565 describes a stretch-wrapped package, process and apparatus which employs a stretch wrap polyethylene film.
U.S. Pat. No. 4,409,776 discloses a method and apparatus for packing articles with a composite stretch wrap film one surface of which is nonadhesive. The adhesive surface is obtained with an "adhesive film" such as one fabricated from ethylene-vinyl acetate copolymer, 1,2-polybutadiene or styrenebutadiene copolymer and the nonadhesive surface is obtained with a "nonadhesive film" such as one fabricated from a crystalline polyolefin, e.g., polyethylene, polypropylene or ethylene-propylene copolymer.
It is an object of the present invention to provide a thermpolastic stretch wrap film of simplified construction, e.g., a monolayer film, possessing a significant cling property on at least one of its major surfaces and a slide property on its other surface.
It is another object of the present invention to provide a stretch wrap film fabricated from an LLDPE resin inherently exhibiting a significant level of cling on one surface thereof in the absence of cling additive and a slide property on the opposite surface thereof due to the presence of particulate antiblock agent mechanically bonded to said surface.
Other objects of the invention include the use of a stretch wrap film of the aforementioned characteristics in the overwrapping of a plurality of goods, e.g., a pallet load, to provide a unitized packaged unit.
SUMMARY OF THE INVENTION
In accordance with the foregoing objects, a stretch wrap film is provided which comprises a layer of thermoplastic film possessing a significant cling property on one surface thereof and no significant cling property on the opposite surface thereof, the latter surface possessing a slide property when in contact with a like film surface with relative motion therebetween due to the presence of particulate antiblock agent mechanically bonded to said surface.
The term "antiblock" agent shall be understood herein to mean any material which is effective to prevent or discourage any significant degree of cling between the surface of the film to which it is applied and a like film surface and to confer a slide property on said surface relative to a like film surface.
The foregoing film possesses several advantages over a film in which antiblock agent is distributed substantially uniformly throughout a discrete film layer as, for example, in the multilayer film of U.S. Pat. No. 4,518,654 supra. As previously noted, particulate antiblock agent is uniformly distributed throughout non-cling layer B of this film. Not only do the antiblock agent particles which are not at the surface of this film layer contribute nothing to the non-cling/slide properties of such surface (and as such, can be regarded as wasted material), their presence within the interior of film layer B can serve as points of tear and/or fracture initiation which compromise the tear and puncture resistance properties of the total film structure. In contrast to this arrangement, the particulate antiblock agent in the stretch wrap film of this invention is applied to the one film surface only after the film has been formed, e.g., by slot-cast or blown tube extrusion. Thus, only the composition and properties of the film at its surface are altered or affected, the composition and properties of the rest of the film remaining essentially unchanged.
Another significant advantage of the stretch wrap film is that it can, if desired, be fabricated from a monolayer thus avoiding the material and/or processing costs associated with the production of a multilayer stretch wrap film.
The stretch wrap film of this invention can be used to overwrap one or a group of articles to form a unitized monolithic packaged unit employing any of the known and conventional tension-wrapping techniques such as those described above.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a schematic representation of a stretch wrap film of this invention; and,
FIG. 2 is a schematic representation of a process for fabricating the film of this invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Any thermoplastic film-forming resin which is capable of being fashioned into a stretch wrap film is suitable for use herein. Films formed from the polyolefin homopolymers and copolymers, with and without minor amounts of blending, or alloying, resins, are generally preferred. Examples of suitable film-forming resins include the polyethylenes, e.g., HPLDPE and LLDPE resins, ethylene-vinyl acetate copolymer, ethylene-vinyl acetate-vinyl alcohol terpolymer, ethylene-propylene copolymer, ethylene-butene-1 copolymer, ethylene-propylene-butene-1 terpolymer, crystalline polypropylene, polybutene-1, and the like.
The film can be one which inherently possesses a significant cling property, e.g., one fabricated from an LLDPE film of relatively high n-hexane extractibles content as more fully described below, whose natural cling force may be enhanced or supplemented by the addition of one or more cling additives. The film can also be one which initially possesses little if any inherent cling force, e.g., a film made from LLDPE resins of typically low n-hexane extractibles content referred to above, and to which one or more cling agents have been added. Either type of LLDPE resin, especially the former, is preferred for use in fabricating the stretch wrap film of this invention.
Cling additive, where present, can be selected from any of the materials previously used to confer a cling force to thermoplastic film. Examples of such materials include ethylene-vinyl acetate copolymers, polyisobutylenes of relatively low molecular weight, e.g., from about 200 to about 300, fatty acid glycerides such as the glycerol oleates, alkali metal sulfosuccinates, amorphous atactic polypropylenes, e.g., those having average molecular weights of about 2000, polyterpenes, and so forth. The cling additive can be present in the film in widely varying concentrations, e.g., from about 0.5 to about 10, and advantageously, from about 1 to about 5, weight percent of the film-forming resin component.
For reasons of cost, it is preferred to provide the stretch wrap film of the present invention as a single film layer possessing a significant inherent and/or imparted cling property on one surface and non-cling/slide properties on the other surface. Such an embodiment is schematically depicted in FIG. 1 in which a cross section of film 10, blown or cast from a suitable resin 11 such as LLDPE, and shown greatly exaggerated for purposes of illustration, possesses inherent or added cling on surface 12 and a slide property on non-cling surface 13 conferred by particles of antiblock agent mechanically bonded thereto.
This film as well as the multilayer variations thereof can be provided in the manner schematically shown in FIG. 2. Thus, a blown or cast monofilm or coextruded multilayer film possessing cling on the upper surface thereof and whose surfaces are still hot enough to be in a semi-plastic state is passed over a powder applicator, e.g., of the blower-type, which directs a stream of particulate antiblock agent against the lower surface of the film. A quantity of the powder, specific useful levels of which can be experimentally calculated for a given film formed under given film-forming conditions, will adhere to the semi-plastic lower surface of the film and, following passage of the film through a pair of rolls, will become mechanically bonded thereto. Ordinarily, from about 0.01 to about 1.0 or more, and preferably from about 0.1 to about 0.5, weight percent of particulate antiblock agent by weight of the resin component of the entire film structure will be taken up by the under surface of the film in this manner and more or less become uniformly distributed on such surface. These levels of particle impregnation are generally quite effective in overcoming and rendering negligible the cling force exhibited by this surface of the film and imparting a significant slide property thereto. Any non-adherent antiblock agent particles can be conveniently removed by application of vacuum to the under surface of the film. Finally, the one-sided cling stretch wrap film can be subjected to one or more downstream operations such as surface treatment by flame, chemical or corona discharge, slitting, winding, etc.
When a blown tube of film is involved, the particles of antiblock agent can be applied either to the interior or to the exterior surface of the still-hot film. In the case of the former, a "cloud" of particulate can be formed within the film tube or bubble; in the case of the latter, an annular powder spraying element can be provided which completely surrounds the film tube and directs the powdery antiblock agent against this surface It is also within the scope of the invention to reheat a film produced by any film forming operation to the point where particles of antiblock agent directed aginst one of its surfaces will mechanically bond thereto.
Alternatively, particulate antiblock agent can be electrostatically deposited upon the one surface of the film employing known techniques and equipment, e.g., the Series 400 Dry Wax Applicator manufactured by Oxy-Dry Corporation, Roselle, N.J.
The particulate antiblock agent can be selected from amongst any of a wide variety of inorganic and organic materials which impart non-cling/slide properties to the surface of a thermoplastic film. Inorganic materials which, in powder form, are useful as antiblock agents include those disclosed in U.S. Pat. No. 4,518,654, supra, and generally include such materials as the silicas, diatomaceous earth, calcium silicate, bentonite, clay, talcs, etc. Organic materials include starches and various kinds of finely divided polymeric materials, e.g., polyethylenes. The average particle size of the antiblock agents can vary widely, e.g., from about 10 to about 200, and preferably from about 20 to about 100, millimicrons.
Although the film of the present invention is preferably realized in the form of a single layer, it is also within the scope of this invention to provide a multilayer film, or laminate, made up of two, three or even more individual layers. In the multilayer embodiment of the film herein, the exposed surface of one outer layer will exhibit a significant cling force while the exposed surface of the other outer layer will exhibit non-cling/slide properties. For example, a two layer structure can be provided in which an LLDPE-based layer possessing inherent cling and/or cling additive is coextruded with an HPLDPE-based layer impregnated with particulate antiblock agent as described above. In one three-layer laminate embodiment of the film herein, an LLDPE core layer is coextruded with a first surface layer based on EVA copolymer which provides an effective level of cling force and a second surface layer of HPLDPE containing particulate antiblock agent mechanically bonded to its exposed surface. Other combinations are, of course, possible.
As previously stated and due to its excellent physical properties such as high tear strength and excellent puncture resistance, the LLDPE resins are preferred for the construction of the present film. The term "LLDPE" is to be understood in the generally recognized sense of a copolymer of ethylene and small amounts, e.g., from 1 to about 10 weight percent, of at least one other copolymerized alpha-monoolefin comonomer possessing from 4 to about 10, and preferably, from 5 to 8, carbon atoms. Typical comonomers include butene-1, 1,3-methyl-butene-1, 1,3-methyl-pentene-1, hexene-1, 4-methylpentene-1, 3-methyl-hexene-1; octene-1, decene-1, etc. The LLDPE resins are prepared at relatively low pressures employing coordination-type catalysts. Reference may be made to U.S. Pat. Nos. 3,645,992; 4,076,698; 4,011,382; 4,163,831; 4,205,021; 4,302,565; 4,302,566; 4,359,561; and 4,522,987, supra, for more details of the manufacture and properties of LLDPE resins including those which are useful herein. An especially preferred type of LLDPE resin is one containing an unusually high content of n-hexane extractibles since such a resin can possess a fairly high level of cling without the need to add cling-conferring materials. Although it has not been confirmed that the n-hexane extractibles are, in fact, the cause of the inherent cling property of a film fabricated from such a resin, a correlation between cling and the level of such extractibles has been observed lending support to the view that the extractibles are indeed responsible for the cling behavior. As measured by the n-hexane extractibles method described in 21 C.F.R. 177.1520 to which reference may be made for specific details, an LLDPE film of about 1.5 mils thickness containing from about 3 weight percent up to as high as 15 weight of such extractibles will exhibit a significant level of cling. Preferably, the LLDPE film or film layer herein will contain from about 4 to about 10 and still more preferably, from about 5 to about 8, weight percent of n-hexane extractibles.
The level of n-hexane extractibles in such a film can also be expressed in terms of a specific cling force. Thus, the n-hexane extractible component of the LLDPE film can be such as to provide a cling force of at least about 75 grams, preferably at least about 100 grams and more preferably at least about 200 grams. Cling forces exceeding 200 grams, e.g., 300-400 grams, can also be achieved. The preferred high n-hexane extractibles LLDPE resins of this invention have a density ranging from about 0.905 to about 0.940 gm/c.c. and a melt index of from about 1 to about 6. Such resins can contain known and conventional cling additives, e.g., any of those previously mentioned, to augment the cling property which they already inherently exhibit.
Film thickness, whether of a monolayer or a multilayer film, can vary widely and, in general, can be a thickness which is typical for stretch wrap films. A total film thickness of from about 0.4 to about 2.5 mils, preferably from about 0.5 to about 0.9 mils, is suitable for most applications. In the case of multilayer films constructed in accordance with this invention, the outer layer(s) can represent from about 10 to about 90, and preferably from 30 to about 80, percent of the total gauge thickness with the other layer(s) representing the balance of the thickness.
Either or both major surfaces of the film can be treated by such known and conventional post-forming operations as corona discharge, chemical treatment, flame treatment, etc., to modify the printability or ink receptivity of the surface(s) or to impart other desirable characteristics thereto.
The stretch wrap film of this invention can, if desired, be provided in the non-stretched, i.e., unoriented, or at most only modestly stretched, state prior to use or it can be provided as a pre-stretched film with little, if any, additional stretch being applied to the film at the time of use. Thus, the film herein can be capable of undergoing stretch from about 0 to about 400, and preferably from about 75 to about 250, linear percent during the overwrapping operation.
Where the manufacture of a multilayer film is concerned, it is preferred to employ known and conventional techniques of coextrusion to assemble the composite structure. Reference may be made to U.S. Pat. No. 3,748,962, the contents of which are incorporated by reference herein, for details of a coextrusion procedure which can be employed in the fabrication of a multilayer film in accordance with this invention.
It is, of course, to be understood that the film of this convention can contain one or more other known and conventional film additives, e.g., fillers, pigments, antioxidants, UV stabilizers, and the like, in the customary amounts.
The following examples are illustrative of the one-sided cling stretch wrap film of this invention.
EXAMPLE 1
An LLDPE resin (ethylene-octene-1 copolymer) is extruded at 520° F. through a slot die onto a cast roll at line speeds of 750 ft/min to provide a monolayer film of about 0.8 mils. The cling force of this film is about 160 gm, one which renders the film suitable for commercial stretch wrap application with or without added cling agent. Before the surfaces of the film have had an opportunity to completely set, approximately 0.1 weight percent of particulate aluminum silicate Na 2 O. A1 2 O 3 .SiO 2 .4H 2 O (average particle size of 3-4 microns) antiblock agent is mechanically bonded to the under surface of the film employing the powder applicator method described in connection with FIG. 2. The resulting film continues to exhibit a relatively high cling force on its upper surface but essentially no cling force on its under surface which instead exhibits a slide property when in contact with a layer of itself.
EXAMPLE 2
Example 1 is substantially repeated with a monolayer film extruded from an LLDPE resin possessing little inherent cling force but containing 3 parts of polyisobutylene (number average molecular weight of 2060) to impart a relatively high level of cling force thereto. The resulting stretch wrap film possesses much the same surface properties as the film of Example 1.
EXAMPLE 3
A two layer film structure of about 0.8 mils total thickness is formed by coextruding an EVA copolymer film of about 0.1 mils thickness and possessing a high level of cling with the LLDPE resin of Example 2 of about 0.7 mils thickness and to which no cling agent is added. The exposed surface of the LLDPE layer is then provided with a superficially embedded coating of particulate antiblock agent in essentially the same manner as in Example 1. The resulting stretch wrap film possesses properties at its exposed surfaces similar to the films of Examples 1 and 2.
EXAMPLE 4
Example 3 is substantially repeated but with a three layer film structure formed by coextruding the LLDPE film (about 0.6 mils thickness) with an EVA copolymer film (about 0.1 mils thickness) on one surface and an HPLDPE film (about 0.1 mils thickness) on the other. The exposed surface of the EVA surface layer exhibits cling, and the exposed surface of the HPLDPE film exhibits non-cling/slide properties, similar to those of the films of Examples 1, 2 and 3. | A method for forming a one-sided cling stretch wrap film by adhering a particulate antiblock to one surface of the film while the surface is in a semiplastic state, applying a particle-embedding force to the surface and removing excess particulate matter. The thermoplastic stretch wrap film exhibits a significant level of cling on one surface but no appreciable cling force on the other, the latter surface exhibiting a slide property when in contact with a film or like surface due to the presence of particulate antiblock agent mechanically bonded thereto. The film can be used to overwrap one or a group of articles to form a unitized packaged unit employing any of the known and conventional tension-wrapping techniques. Because of its one-sided cling and slide capabilities, pallet loads overwrapped with the film and in mutual contact avoid film tearing or destruction when the pallet loads are separated from each other. | 1 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a system for miter cutting, and more particularly, to a system for miter cutting that includes a device for modeling the angle of convergent surfaces and transposing the modeled angle to a miter saw for miter cutting through a slot defined on the miter saw.
2. Background of the Related Art
The primary function of a miter saw is to cut a piece of material (hereinafter also referred to as a “workpiece”) at a defined angle. Miter saws are most often used to prepare moldings or decorative trim to fit adjacent to surfaces that converge to form an angle, such as an inside or outside corner, so that the moldings or trim appear to follow along the surfaces continuously.
For practical reasons as well as aesthetics, the workpieces are fit to the convergent surfaces by cutting each of the workpieces at an angle which equals, as nearly as possible, one half of the angle formed at the convergence.
Most, if not all, miter saws have preset locking positions for various angles and setting the cutting angle is easily accomplished if the convergence angle corresponds with one of these positions. For example, virtually all miter saws have a preset position for 45 degrees to facilitate cutting workpieces to fit a 90 degree convergence angle.
However, the process becomes more difficult if the convergence angle does not correspond to an angle having a preset cutting position on the miter saw. This circumstance is encountered more often than not, especially throughout existing structures, such as residential homes and apartments.
In these circumstances, half the convergence angle must be measured and transferred to the miter saw in a way that enables the miter saw to be positioned for cutting each workpiece accordingly. Moreover, most moldings or trim are not of equidimensional design, in that they have a planar surface which opposes an ornamental surface and top and bottom edges which may differ in width. For such applications, the miter saw can be set so that a first workpiece is cut to half the convergent angle for the workpiece to be placed along a first convergent surface, but the miter saw must then be set to the inverse or mirror image of the first angle before cutting the second workpiece so that the second workpiece can be positioned along the second convergent surface with the correct orientation. Thus, the measured angle of convergence must be measured and/or transferred to the miter saw twice.
Some devices exist which can measure both internal and external existing angles in degrees, enabling the operator to set the miter saw to one half of that angle by using the saw's miter scale. Other devices duplicate the existing angle and provide a means for transferring one half of that angle to the workpiece by pencil, or scribe, enabling the operator to set the miter saw by visual reference to that line.
The primary problems associated with using such devices are that they are prone to inaccuracies, because, among other things, they involve one or more intermediate steps between the measurement of the existing angle and the setting of the miter saw, each of which is capable of introducing error.
U.S. Pat. No. 5,473,821 to DeMarco discloses a device that can model a convergence angle and transfer one half of that angle to a power miter saw, but only if the miter saw is manufactured to resemble the miter saw described by DeMarco (hereinafter also referred to as the “DeMarco miter saw”). The Demarco miter saw, as described in the '821 patent, deviates from standard power miter saws so much that it would be impossible to use the DeMarco angle-modeling device on miter saws which have not been specifically manufactured in accordance therewith. DeMarco does not demonstrate flaws in the standard power miter saw design or provide justification for changing manufacturing practices to produce miter saws as those shown in the '821 patent, and his design introduces a variety of problems not presented by the standard design.
For example, a workpiece placed on the DeMarco miter saw is held against a guide fence on only one side of the cut rather than both sides as it is with standard designs. This configuration decreases support for the workpiece and increases the possibility that it will move during the cutting process, thereby compromising accuracy, since the cutting action of the blade tends to move or bend the workpiece. The configuration also reduces the operator's options with regard to stabilizing the workpiece against the fence, thus creating safety issues which are not found in the standard design.
Another problem with the DeMarco design relates to the need to move the fences to duplicate the angel of convergence. This configuration increases the complexity and difficulty associated with using the DeMarco miter saw because it requires the reorientation of the workpiece, and any workpiece support system, for different angles and for mitering separate pieces to frame the same angle. In contrast, with the standard design the workpiece is always cut along the same axis, which generally corresponds to a workbench or other support system for the workpiece.
The DeMarco miter saw presents further difficulty in using it to frame an interior angle because each fence blocks the path of a workpiece placed against the other, thus eliminating the operators ability to make one cut for both dimension and angle.
Thus, there is a need for a device which overcomes the problems associated with the prior art as described above. In particular, what is needed is a system or device for modeling an angle formed by convergent surfaces and transferring one half of that angle directly to a miter saw, which can be employed with power miter saws of standard design and hand miter saws designed to accommodate it. Clearly, a device such as this would increase the speed, accuracy and efficiency of the miter saw and miter cutting process.
SUMMARY OF THE INVENTION
The present invention solves the problems of the prior art by, among other things, providing a device for modeling an angle formed by two convergent surfaces and a system for transferring one half of that modeled angle directly to a miter saw to facilitate the cutting of workpieces to border the convergent surfaces, which can be manufactured with or retrofitted onto a standard power miter saw and can also be used with a hand miter saw which is designed to accommodate it.
The present invention consists of a tool and miter saw having a slot defined thereon. The miter saw is configured so that the slot remains parallel to the cutting plane of the miter saw as it is rotated relative to a fixed fence or other device for aligning the workpiece. The tool models the angle of convergence via pivotally connected angle framing arms which are then fixed in position; bisects that angle by support links which are pivotally connected to each other and to each of the framing arms; and transfers the appropriate cutting angle to the miter saw. In this embodiment, the transfer is accomplished by one or more positioning members, which are used to align the bisecting line of the convergence angle with the longitudinal axis of the slot.
The tool is configured so that one framing arm may be placed against and adjacent to each of the convergent sides of an interior angle, with the pivotal coupling of the framing arms being equidistant from the outside edge of each. The pivotal couplings of the framing arms to the support links are equidistant from the outside edge of each framing arm and from the pivotal coupling of the framing arms. The pivotal coupling of the support links is equidistant from the pivotal coupling of each support link to a framing arm.
The present invention is also directed to a system for facilitating miter cutting which includes a tool for modeling a convergence of two surfaces having a first elongate framing arm pivotally coupled with a second elongate framing arm. The first and second framing arms are interconnected by two support links. The first and second framing arms are each pivotally coupled to a support link, which support links, in turn, are pivotally coupled to each other.
This embodiment of a tool constructed in accordance with the present invention also includes a pair of miter positioning members that extend in the same general direction, substantially perpendicularly with respect to the plane of the tool. The miter positioning members are centered on a line between the pivotal coupling of the framing arms and the pivotal coupling of the support links. Preferably, one positioning member is aligned with and directly below the pivotal coupling of the framing arms and the other is aligned with and directly below the coupling of the support links.
A fastener is also provided for adjusting the rigidity of the tool to control the pivotal movement of the first and second framing arms. The fastener may be associated with one or more of the pivotal couplings.
In one embodiment, the tool includes an elongate central arm which shares the pivotal coupling between the first and second framing arms and includes a longitudinal slot defined therein along which the pivotal coupling of the support links is slidably mounted. In this embodiment, the position of the framing arms may be locked by restricting slidable movement of this pivotal coupling along the longitudinal slot.
A tool constructed in accordance with the present invention can also include a setting or support structure which permits modeling external angles. This may include extending the length of the first and second framing arms along their respective longitudinal axes, such as by attaching extension arms of adjustable length to the first and second framing arms.
The present invention is also directed to a miter saw which includes a base having a rotatably mounted carriage disposed thereon that supports a planar work surface, a fence for aligning and affixing the workpiece thereto, which may be in two or more linearly aligned fence segments, is perpendicular to the working surface and is mounted on the base or in such other manner that it remains stationary as the work surface rotates; a knob or other assembly for directing the rotation of the rotatably mounted carriage and work surface disposed thereon and locking the carriage and work surface in a desired position; and a pivoting arm or other means for bringing a saw blade to the work surface which is mounted on the carriage and rotates with the work surface.
This embodiment of a system constructed in accordance with the present invention includes a substantially planar kerf plate for being mounted in, and substantially flush with, the rotatably mounted work surface of a miter saw either as original equipment on a miter saw designed to be utilized with the present invention or as a replacement for the kerf plate on an existing miter saw. The kerf plate of this embodiment has a central slot which is substantially parallel to the cutting plane and configured and dimensioned for engaging the miter positioning members of the tool constructed in accordance with the present invention and receiving the saw blade. Preferably, the kerf plate is fabricated from a non-ferrous material.
The system constructed in accordance with the present invention is generally intended for use as described herein. For an interior angle formed by the convergence of two surfaces, the angle is modeled and one half of that angle transposed to the miter saw by placing each framing arm adjacent to one of the surfaces, locking the tool in that position, engaging the miter positioning members in the miter saw kerf plate slot, rotating the work surface until a framing arm is adjacent to the fixed fence and then locking the work surface in that position.
For an exterior angle formed by the convergence of two surfaces, the angle is modeled and one half of that angle transposed to the miter saw by extending the framing arms of the tool, placing each extended arm adjacent to one of the surfaces, locking the tool in that position, releasing or removing the extending portions of the framing arms, engaging the miter positioning members in the kerf plate slot, rotating the work surface until a framing arm is adjacent to the fixed fence and then locking the work surface in that position.
To cut framing pieces for the angle, the saw is set twice. The first piece is cut after the working surface has been rotated to one side, bringing one framing arm to a position adjacent to the fence, and the second piece is cut after the working surface has been rotated to the other side, bringing the other framing arm to a position adjacent to the fence.
In a preferred embodiment constructed in accordance with the present invention, the miter saw includes a base having a rotatably mounted carriage disposed thereon which supports a planar work surface and a locking knob assembly for directing and locking its rotational movement; a fence for aligning and holding the work piece consisting of two fence segments, one on each side of the cutting plane, which are perpendicular to the work surface, linearly aligned and mounted on the base in such a manner that they remain stationary as the work surface rotates; and a spring loaded pivot joint and pivotal arm which supports a housing for a circular blade and electric drive motor. The pivot joint and pivotal arm are configured and mounted to rotate with the work surface, thereby maintaining a fixed position relative to the work surface, and establish a cutting plane which is perpendicular to the work surface and intersects the rotational center of the carriage and work surface.
The miter saw also includes a substantially planar slotted kerf plate mounted in, and substantially flush with, the work surface. The kerf plate slot is disposed over an aperture in the work surface, parallel with respect to, and centered on, the cutting plane. The slot is configured and dimensioned to receive the circular saw blade and engage the miter positioning members of an angle modeling device constructed in accordance with the present invention.
The modeling device includes a first elongate framing arm pivotally coupled with a second elongate framing arm about an elongate central arm. The elongate central arm includes a longitudinal slot defined therein. Two support links are interconnected with the first and second framing arms by pivotal couplings. The pivotal coupling connecting the support links to each other is mounted on the central arm to slide along the longitudinal slot, and includes a fitting, such as a threaded shaft and wing nut or threaded knob, configured to compress the linking arms and the central arm, thereby locking the device in position.
In accordance with this preferred embodiment, the angle modeling device includes two miter positioning members extending in the same direction, perpendicularly with respect to the plane of the tool. One such positioning member is aligned with and directly below the pivotal coupling of the framing arms while the other positioning member is aligned with and directly below the coupling of the support links.
In addition, the device of this preferred embodiment includes detachable extension arms of variable lengths, which extend the length of the first and second framing arms along their respective longitudinal axes, thereby providing a tool to model exterior angles.
In a second preferred embodiment constructed in accordance with the present invention, the miter saw includes a base having a rotatably mounted carriage disposed thereon which supports a planar work surface and a locking knob assembly for directing and locking its rotational movement; a fence for aligning and holding the workpiece consisting of two fence segments, one on each side of the cutting plane, which are perpendicular to the work surface, linearly aligned and mounted on the base in such a manner that they remain stationary as the work surface rotates; two slotted guides mounted at the front and back of the rotatably mounted carriage in such a manner that they rotate with the work surface, thereby maintaining a fixed position relative to it. The slots in the guides are perpendicular to the work surface and configured to engage and guide a hand saw. The guides are mounted in a manner to establish a cutting plane which is perpendicular to the work surface and intersects the rotational center of the carriage and work surface.
The miter saw also includes a substantially planar kerf plate mounted in and substantially flush with, the work surface. The kerf plate slot is disposed over an aperture in the work surface, is parallel to the cutting plane, centered on it, and configured and dimensioned to receive the hand saw blade and to engage the miter positioning members of an angle modeling device as described above.
The present invention is also directed to a method for mitering two pieces of material to frame converging surfaces. The method includes the step of applying a tool at the convergence of the converging surfaces to model the angle of convergence. The tool may include first and second elongate framing arms pivotally coupled to each other at an end thereof, first and second support links, each pivotally coupled to a framing arm at a point which is equidistant from the pivotal coupling of the framing arms. The support links can be pivotally coupled to each other at a point equidistant from their respective pivotal couplings with the framing arms. The tool may further include fastening means for temporarily setting the first and second framing arms in a desired angular relationship facilitated by the pivotal coupling of the first and second framing arms, pivotal couplings of the first and second support links to the first and second framing arms, and the pivotal coupling of the first and second support links to each other, and at least two positioning members extending substantially perpendicular to the plane of the tool and coaxial with the pivotal coupling of the framing arms and the pivotal coupling of the first and second support links to each other, whereby the axis formed between the positioning members bisects the angle formed by the coupling of the first and second framing arms.
The method also includes the steps of locking the tool to maintain the first and second framing arms in a position corresponding to the angle of convergence, and affixing the tool to a miter cutting system.
The miter cutting system may include a rotatable planar work surface and stationary guide fence for supporting a work piece and positioning the work piece in an angular relationship for cutting with a saw, receiving means for the at least two positioning members in the rotatable work surface, whereby alternate rotation of the work surface such that the first and second framing arms abut alternate sides of the guide fence positions the work surface for cutting a work piece along the axis formed between the positioning members.
The positioning members of the tool being received by the receiving means, the method further includes the steps of rotating the work surface until one of the framing arms contacts the guide fence, positioning a first work piece on the work surface in alignment with the guide fence and cutting the work piece with a saw, and removing the cut work piece. With the positioning members of the tool being received by the receiving means, the method further includes rotating the work surface until the other one of the framing arms contacts the guide fence, positioning a second work piece on the work surface in alignment and with the guide fence, cutting the work piece with a saw; and removing the cut workpiece.
Other objects and advantages of the invention will be apparent from the following description, the accompanying drawings and the appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
So that those having ordinary skill in the art to which the present invention appertains will more readily understand how to make and use the same, reference may be had to the drawings wherein:
FIG. 1 is a top plan view of a tool for modeling angles constructed in accordance with the present invention;
FIG. 2 is a side elevational view of the tool illustrated in FIG. 1 ;
FIG. 3 is a top plan view of the tool shown in FIG. 1 , illustrating extensions to the framing arms and attachment points for extensions;
FIG. 4 is a perspective view of a power miter saw of generally standard design;
FIG. 5 is a front view of the miter saw shown in FIG. 4 , illustrating the rotational movement of the working surface and pivotal arm provided by the rotatably mounted carriage;
FIG. 6 is a perspective view of a miter saw shown in FIG. 4 , illustrating the downward or cutting pivotal movement of the arm used to cut a workpiece placed on the worksurface;
FIG. 7 is a top view of the tool shown in FIG. 1 positioned in an inside corner formed by two convergent surfaces and configured to model the angle of convergence;
FIG. 8 is a top view of the tool taken from the inside corner as shown in FIG. 7 , wherein the tool is positioned on the kerf plate of a miter saw work surface in accordance with the present invention;
FIG. 9 is a top view of the tool positioned on the kerf plate of a miter saw as shown in FIG. 8 , wherein the miter saw work surface has been rotated so that a first arm of the tool contacts the fixed fence;
FIG. 10 is a top view of the miter saw work surface rotated as shown in FIG. 9 with a workpiece positioned on the work surface for cutting with the miter saw;
FIG. 11 is a top view of the inside corner of FIG. 7 , wherein the workpiece cut by the miter saw as shown in FIG. 10 in accordance with the present invention is positioned to border one of the two converging surfaces forming the inside corner;
FIG. 12 is a top view of the tool configured to model the inside corner as shown in FIG. 7 and positioned on the kerf plate of a miter saw work surface in accordance with the present invention, wherein the miter saw work surface has been rotated so that the second arm of the tool abuts the fixed fence;
FIG. 13 is a top view of the miter saw work surface rotated as shown in FIG. 12 with a workpiece positioned on the work surface for cutting with the miter saw;
FIG. 14 is a top view of the inside corner of FIG. 11 , wherein the workpiece cut by the miter saw as shown in FIG. 13 in accordance with the present invention is positioned to border the second of the two converging surfaces forming the inside corner;
FIG. 15 is a top view of the tool shown in FIG. 1 with arm extensions, such as those depicted in FIG. 3 , wherein the tool is positioned in an outside corner formed by two convergent surfaces and configured to model the angle of convergence;
FIG. 16 is a top view of the tool taken from the outside corner as shown in FIG. 15 , wherein the tool is positioned on the kerf plate of a miter saw work surface without arm extensions in accordance with the present invention;
FIG. 17 is a top view of the tool positioned on the kerf plate of a miter saw as shown in FIG. 16 , wherein the miter saw work surface has been rotated so that a first arm of the tool contacts the fixed fence;
FIG. 18 is a top view of the miter saw work surface rotated as shown in FIG. 17 with a workpiece positioned on the work surface for cutting with the miter saw;
FIG. 19 is a top view of the outside corner of FIG. 15 , wherein the workpiece cut by the miter saw as shown in FIG. 18 in accordance with the present invention is positioned to border one of the two converging surfaces forming the outside corner;
FIG. 20 is a top view of the tool configured to model the outside corner as shown in FIG. 15 , wherein the tool is positioned on the kerf plate of a miter saw work surface without arm extensions in accordance with the present invention and the miter saw work surface has been rotated so that the second arm of the tool abuts the fixed fence;
FIG. 21 is a top view of the miter saw work surface rotated as shown in FIG. 20 with a workpiece positioned on the work surface for cutting with the miter saw;
FIG. 22 is a top view of the outside corner of FIG. 19 , wherein the workpiece cut by the miter saw as shown in FIG. 21 in accordance with the present invention is positioned to border the second of the two converging surfaces forming the outside corner;
FIG. 23 is a top plan view of a miter saw work surface with a kerf plate constructed in accordance with the present invention secured thereon.
FIG. 24 is a top plan view of a hand miter saw designed to accommodate a tool for modeling angles constructed in accordance with the present invention; and
FIG. 25 is a front elevational view of the saw shown in FIG. 24 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
The advantages of a system for perfecting miter cuts constructed or retrofitted on a miter saw in accordance with the present invention will become more readily apparent to those having ordinary skill in the art from the following detailed description of certain preferred embodiments taken in conjunction with the drawings which set forth representative embodiments thereof. Unless otherwise apparent, or stated, directional references, such as “right,” “left,” “upper,” “below,” “horizontal” “vertical,” “upward” and “downward”, are intended to be relative to the orientation of a particular embodiment of the invention as shown in the first numbered view of that embodiment. In addition, a given reference numeral indicates the same or similar structure when it appears in different figures and like reference numerals identify similar structural elements and/or features of the subject invention.
Referring now to FIG. 1 , in which there is illustrated a preferred embodiment of a miter angle modeling and transferring tool constructed in accordance with the present invention and generally designated by the reference numeral 10 . Tool 10 is substantially planar and includes a left elongate framing arm 12 and a right elongate framing arm 14 . This preferred embodiment also includes an elongate central arm 16 . The left arm 12 and right arm 14 are pivotally connected adjacent to a first end of each, respectively, by coupling 18 , and are configured so that one framing arm may be placed against and adjacent to each of the convergent sides of an interior angle. Left and right arms 12 and 14 can be pivoted via coupling 18 to define an angle between arms 12 and 14 . As can be best viewed in FIG. 2 , coupling 18 includes a miter positioning member 20 which extends perpendicularly with respect to the plane of tool 10 . In this embodiment, miter positioning member 20 is essentially a protrusion, referred to hereinafter as locator pin 20 . Locator pin 20 is positioned equidistant from the outer edges of left and right arms 12 and 14 , respectively.
A left support link 22 is pivotally interconnected adjacent to a first end thereof, with left arm 12 at a coupling 24 . Similarly, a right support link 26 is pivotally interconnected adjacent to a first end thereof, with right arm 14 at a coupling 28 .
Left and right support links 22 and 26 are pivotally connected to central arm 16 by a coupling 30 . Preferably, coupling 30 is disposed adjacent the second ends of each of the support links 22 and 26 . Pivotal connections 24 and 28 are equidistant from pivotal connection 18 , pivotal connection 30 and from the outside edges of framing arms 12 and 14 .
In this embodiment, coupling 30 includes another protruding miter positioning member 32 , which is also referred to hereinafter as locator pin 32 . Locator pin 32 is substantially centered on and extends from coupling 30 substantially perpendicularly with respect to the plane of tool 10 , and in the same general direction as locator pin 20 .
In the embodiment of the present invention depicted in the figures, coupling 30 is slidably mounted on central arm 16 for movement within a central slot 34 defined longitudinally in central arm 16 . Locator pin 32 is substantially centered on coupling 30 and also is slidably engaged within central slot 34 by virtue of its connection with coupling 30 . Preferably, coupling 30 may be tightened, by a threaded shaft and knob or similar device, so that coupling 30 remains in its position, thus preventing pivotal movement by tool 10 .
An independent fastening assembly may also be used with the present invention, such as a wing-nut and threaded bolt, which can be tightened to lock coupling 30 in position along central slot 34 . Other fastening assemblies which prohibit pivotal movement of left and right arms 12 and 14 may also be utilized.
Left elongate arm 12 and right elongate arm 14 are expandable along the longitudinal axis towards coupling 18 . For example, this may be accomplished by including additional members of the same width as the arms 12 and 14 , respectively, which are slidably attached thereto, or by including arms 12 and 14 which are telescoping or contain telescoping sections.
In this embodiment of the present invention, as shown in FIG. 3 , extension members 36 having substantially the same width as arms 12 and 14 , respectively, but greater longitudinal length, are attached to arms 12 and 14 via fasteners 38 to facilitate the modeling of exterior angles. Fasteners 38 may include bolts and wingnuts, hook and latch, or any other suitable fastening devices. It should be readily apparent to those skilled in the art that it is within the purview of the present invention to provide extension members 36 of various lengths, or extension members 36 which are adjustable, to accommodate a variety of exterior angles and surrounding conditions.
Referring now to FIG. 4 , in which there is illustrated a preferred embodiment of a miter saw orientated for operation thereof, which employs a system constructed in accordance with the present invention designated generally by a reference numeral 40 . Miter saw 40 is powered by an electrical connection to a home outlet, however, the source of power is not critical for the operation of the present invention.
Miter saw 40 includes a base 42 having a generally planar and circular work surface 44 . A fence, consisting of a linearly aligned right side segment 46 and left side segment 48 , is disposed perpendicularly with respect to work surface 44 , is supported by base 42 so that it remains stationary as work surface 44 is rotated and is used to position and support a work piece against surface 44 for cutting. A kerf plate 50 with a longitudinal slot 52 is seated in surface 44 between right side fence segment 46 and left side fence segment 48 . Kerf plate 50 is recessed so that it is substantially evenly aligned with surface 44 . Slot 52 is located over an aperture in the work surface 44 (not shown) and sufficiently sized to receive a saw blade. Furthermore, slot 52 is sufficiently configured to engage pins 20 and 32 therein and may further include keyed notches, indents or the like for matching corresponding keyed elements in pins 20 and 32 . Preferably, for safety reasons, among other things, kerf plate 50 is constructed of a resilient but non-ferrous material, such as plastic.
Work surface 44 is disposed over a carriage 54 mounted on base 42 and configured for rotational movement in the horizontal plane. A locking clamp and knob assembly 56 is disposed on carriage 54 to facilitate movement of the carriage 54 along with work surface 44 . An arm 58 is supported by a spring loaded pivot assembly 60 connected with carriage 54 , which provides for pivotal movement of arm 58 thereby causing the circular blade 62 mounted on its upper portion to move through a vertical plane which is perpendicular to working surface 44 , and passes through and is aligned with the rotational center of carriage 54 and with slot 52 . FIG. 6 best illustrates the manner in which this pivotal movement is utilized to cut material. Pivot assembly 60 and clamp and knob assembly 56 are positioned in substantially opposed, radially outer portions of the carriage 54 .
Carriage 54 facilitates rotational movement of work surface 44 in excess of 45 degrees to the left and right relative to the center alignment (i.e., with slot 52 being set in a substantially perpendicular relationship with respect to base 42 ). FIG. 5 depicts miter saw 40 with carriage 54 rotated to the right and illustrates the manner in which work surface 44 , slot 52 and arm 58 rotate with carriage 54 and maintain their respective positions relative to each other.
A circular blade 62 , which is driven by an onboard motor 64 and covered by a retractable guard 66 , is mounted for rotational motion on the upper portion of arm 58 . A trigger switch 68 in electrical communication with motor 64 is positioned adjacent a handle 70 defined on arm 58 to facilitate activation of blade 62 while moving arm 58 to cut a workpiece on surface 44 , as shown in FIG. 6 .
The system in accordance with the present invention may be used in a variety of ways to produce highly accurate miter angle cuts. FIGS. 7-14 illustrate a preferred method for using tool 10 to model/measure an inside angle (i.e., formed by two recessing convergent surfaces) and transfer that angle to miter saw 40 for cutting a workpiece to fit within the inside angle accordingly.
As shown in FIG. 7 , tool 10 is fit onto inside corner 80 by using right and left framing arms 12 and 14 to form a surrounding border about the convergence, thus matching the angle of inside corner 80 , as defined by a left side surface 82 and right side surface 84 , with arms 12 and 14 . Once the convergence is modeled by tool 10 , the fastener associated with coupling 30 is tightened to ensure that the “framed” position of arms 12 and 14 is maintained. In FIG. 8 , tool 10 is placed on work surface 44 so that pins 20 and 32 are engaged in slot 52 of kerf plate 50 . Using locking clamp and knob assembly 56 , carriage 54 is rotated to move work surface 44 , along with tool 10 while still engaged in slot 52 , so that left arm 12 abuts left side fence segment 48 as shown in FIG. 9 . After positioning work surface 44 , tool 10 is then removed from kerf plate 50 . As shown in FIG. 10 , the workpiece is placed on surface 44 abutting right side and left side fence segments 46 and 48 before being cut by the saw. As shown in FIG. 1 , one end of the cut workpiece matches half the angle of inside corner 80 and can be positioned to border left side convergent surface 82 .
FIGS. 12-14 illustrate the same process for cutting another workpiece so that one end includes an angle matching the right side half of interior corner 80 . The tool 10 is placed back into slot 52 , and work surface 44 is rotated so that right arm 14 abuts right side fence segment 46 . Tool 10 is removed and the workpiece is positioned against the right side and left side fence segments 46 and 48 before being cut. As shown in FIG. 14 , the workpiece can be positioned against right side surface 84 so that the two workpieces fit together and form a border about inside corner 80 .
FIGS. 15-22 illustrate the method for using tool 10 to model/measure the angle of an outside corner 86 formed by two projecting convergent surfaces, a left side surface 88 and a right side surface 90 , and transfer that modeled angle to the miter saw 40 for cutting workpieces to border the outside corner 86 .
As shown in FIG. 15 , extension members 36 are attached to right and left arms 12 and 14 , respectively, to frame outside corner 86 . Once the convergence is modeled, arms 12 and 14 are held in position by tightening the fastener associated with coupling 30 . Extension members 36 are removed and tool 10 is fit into slot 52 of kerf plate 50 , as shown in FIG. 16 . In FIG. 17 , work surface 44 is rotated so that left arm 12 abuts left side fence segment 48 . Tool 10 is removed and the workpiece is placed on surface 44 for cutting with miter saw 40 , as shown in FIG. 18 . For an outside corner such as corner 86 , the workpiece cut with the tool 10 abutting left side fence segment 48 will provide the border for right side surface 90 , as shown in FIG. 19 .
As depicted by FIGS. 20-22 , the process is similar for producing a workpiece that can border left side surface 88 and fit with the right side surface workpiece about outside corner 86 .
The present invention is advantageously adapted to existing miter saws without redesigning or reconfiguring existing equipment, or changing the design of the present invention. As shown in FIG. 23 , any existing kerf plate on a miter saw can be removed by screws 92 and replaced by a kerf plate in accordance with the present invention. The kerf plate may also consist of two parts, each of which defines one half of the central slot.
FIGS. 24 and 25 illustrate the manner in which a tool 10 constructed in accordance with the present invention, as described above, may be used in conjunction with a hand miter saw which is generally designated by the reference numeral 140 .
Hand miter saw 140 includes a base 142 having a rotatably mounted carriage 154 which is configured for rotational movement in the horizontal plane and which supports a generally planar and circular work surface 144 . A fence, consisting of linearly aligned right side and left side segments 146 and 148 is used to position and support a workpiece against surface 144 for cutting. The fence is perpendicular to work surface 144 and is supported by base 142 so that it remains stationary as work surface 144 rotates.
A substantially planar kerf plate 150 with a longitudinal slot 152 is seated in surface 144 between right side fence segment 146 and left side fence segment 148 . Kerf plate 150 is recessed so that it is substantially evenly aligned with surface 144 . Slot 152 is sufficiently sized to receive a saw blade, is located over an aperture in work surface 144 and is configured to engage locator pins 20 and 32 from tool 10 therein. Slot 152 may further include keyed notches, indents or the like for matching corresponding keyed elements in pins 20 and 32 . Preferably, kerf plate 150 is constructed of a resilient but non-ferrous material such as plastic.
A locking clamp and knob assembly 156 is disposed on carriage 154 to facilitate movement of carriage 154 along with work surface 144 . Braces 194 and 196 are supported by carriage 154 for rotational movement therewith. Braces 194 and 196 project above work surface 144 in a spaced relationship at either end of slot 152 . Both braces 194 and 196 contain a slot 198 disposed in the same place, perpendicularly with respect to work surface 144 . Slots 198 are configured and dimensioned to receive a hand saw without restraining the movement in slots 198 associated with cutting. Preferably, the hand saw is of the type commonly known as a back saw. Braces 194 and 198 with slots 198 are mounted and configured to align a hand saw positioned therein with slot 152 in kerf plate 150 .
Tool 10 would be used to model/measure an angle formed by either exterior or interior convergent surfaces in the same manner as in the previous embodiment. The angle is transferred to miter saw 140 in substantially the same manner as described above and illustrated in FIGS. 7 through 22 , except the workpiece is cut with a hand saw.
While the systems and methods for using the system contained herein constitute preferred embodiments of the invention, it is to be understood that the invention is not limited to these precise systems and methods of use, and that changes may be made thereto without departing from the scope of the invention which is defined in the appended claims. | A system for modeling a recessed or protruding angle formed by convergent surfaces and transferring that modeled angle directly to a miter saw for facilitating the cutting of workpieces in conformance with the bisection of that modeled angle. This system may be manufactured with, or retrofitted onto a standard miter saw or used with a hand miter saw designed to accommodate the system. | 4 |
This application is a continuation of U.S. patent application Ser. No. 12/173,076 of Kodi, filed Jul. 15, 2008, entitled “Method Of Attaching Reinforcing Bars”, which is a continuation of U.S. patent application Ser. No. 11/122,195 of Kodi, filed May 3, 2005, entitled “Bar Clip With Flared Legs”, the details of both of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
The present invention relates generally to an apparatus and method of attaching and aligning reinforcing bars in a framework for supporting a concrete matrix. More particularly, this invention pertains to clips for joining reinforcing bars in a framework. Even more particularly, this invention pertains to a clip with flared legs for joining pairs of reinforcing bars in a parallel orientation.
It has been long known in the art of reinforced concrete structures to provide fastening means for aligning and attaching reinforcing bars in a framework prior to encasing such bars in a concrete matrix. One well known fastening means used in forming a framework of reinforcing bars is to wrap adjacent bars with wire ties, or other similar binding materials. Another well known fastening means is to attach such reinforcing bars by welding instead of wrapping. Both of these fastening means provide for attaching bars arranged in either transverse or parallel orientations. However, both means are labor intensive and, thus, more expensive when compared to the use of more recently developed reinforcing bar clips.
Plastic clips have been developed to provide a means of rapidly attaching adjacent reinforcing bars that are arranged in transverse orientations. For example, Padrum, in U.S. Pat. No. 4,110,951, teaches a plastic U-shaped clip formed by two opposing flanges extending from a base. Each of the flanges is split to form opposing and aligned openings within each flange. The clip is positioned and aligned above two reinforcement bars that are in a transverse orientation to each other. Pressure applied to the base causes the first reinforcing bar to be forced between the flanges and held in an upper position. Continued application of pressure upon the base causes the second reinforcing bar to be forced between the opposing split opening in the flanges and held in a lower position independent of the first bar.
A second example of prior art plastic clips is shown in U.S. Pat. No. 5,626,436 to Dragone. The Dragone clip is a U-shaped assembly comprising two parallel longitudinal members connecting two opposed hook assemblies. Each hook assembly comprises two connecting members, each extending from one of the longitudinal members, and a fulcrum section. A hook is formed by two opposing fingers, each attached at an opposite end of the fulcrum section and extending from the fulcrum section in a direction away from the longitudinal members. A gap is formed between each pair of opposing fingers. To install the Dragone clip, a first reinforcing bar is forced between the two opposed hook assemblies and held in an upper position against the parallel longitudinal members. The parallel longitudinal members are squeezed together by the user, causing each pair of opposing fingers to spread apart. The user slips the spread fingers of the opposing hooks over a second reinforcing bar that is positioned transverse to the first bar. The user then releases the parallel longitudinal members. As the parallel longitudinal members separate, each pair of opposing fingers close around the second bar and hold it in a lower position. The Dragone clip is sized so as to hold the second bar against the first bar.
One shortcoming of these two plastic clips is the limited orientations in which they can be used. These clips can only be used with transversely oriented reinforcement bars. However, frameworks of reinforcement bars frequently require attachment of bars in parallel orientations as well as transverse orientations. Previously, no clips existed to attach reinforcement bars in parallel orientations. Where frameworks are constructed using either of the prior art clips, the user can only use such clips to attach transversely oriented bars. All other attachment orientations require the user to employ more labor intensive methods of attaching the bars, such as wire wrap. What is needed, then, is a reinforcement bar clip that can be used to attach adjacent reinforcing bars arranged in a parallel orientation.
To make the task of attaching reinforcement bars in a framework as simple as possible, it would be advantageous if only one type of clip were necessary to join reinforcement bars in either a transverse orientation or in a parallel orientation. Therefore, what is additionally needed is a reinforcement bar clip that can be used to attach adjacent reinforcing bars arranged in either a transverse orientation or in a parallel orientation.
BRIEF SUMMARY OF THE INVENTION
In the preferred embodiment, the present invention includes a color coded molded plastic clip including a pair of opposing clasp assemblies. Each clasp assembly has an upper clasp and a lower clasp for holding, respectively, first and second reinforcement bars in a parallel orientation. Each upper clasp includes a pair of opposing, convexly curved fingers that extend upwards from a transverse support and are attached to a pair of parallel longitudinal supports. Each clasp assembly further includes a second pair of opposing, convexly curved fingers extending downward from either end of the transverse support so as to form a lower clasp.
One novel aspect of the preferred embodiment of the present invention is a pair of flared guides attached to the lower ends of the opposing fingers of each lower clasp. During installation of the clip's lower clasps upon a reinforcement bar, each pair of flared guides engages the bar and guides it to the lower clasp gaps for insertion into the lower clasps.
An alternative embodiment of the present invention additionally includes two alternative upper clasps formed from the longitudinal supports cooperating with the opposed clamp assemblies. Each alternative upper clasp includes an alternative upper seat and an alternative upper clasp gap for receiving and holding a reinforcement bar in an orientation transverse to a reinforcement bar received and held by the lower clasp. Advantageously, the clip of this alternative preferred embodiment can be selectively used to attach and hold two reinforcement bars arranged in either a parallel orientation or in a transverse orientation.
Accordingly it is an object of the present invention to provide a reinforcement bar clip that can be used to attach adjacent reinforcing bars arranged in a parallel orientation.
It is an additional object of the present invention to provide a reinforcement bar clip that can be used to attach adjacent reinforcing bars arranged in either a transverse orientation or in a parallel orientation.
Finally, it is an object of the present invention to provide a means of guiding a reinforcement bar into a clasp during installation of the clip.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
FIG. 1 is an oblique view of a preferred embodiment of the reinforcement bar clip of the present invention.
FIG. 2 is an end view of the clip of FIG. 1 along the longitudinal axis.
FIG. 3 is a side view of the clip of FIG. 1 along the transverse axis.
FIG. 4 is oblique view of the clip of FIG. 1 .
FIG. 5 is an oblique view of the clip of FIG. 1 shown holding two reinforcement bars in a transverse orientation.
FIG. 6 is a similar oblique view of the clip of FIG. 1 shown holding two reinforcement bars in a parallel orientation.
DETAILED DESCRIPTION OF THE INVENTION
One preferred embodiment of the reinforcement bar clip 10 of the present invention is shown in FIG. 1 , wherein orientation of the clip 10 is shown with reference to the vertical direction arrow 15 , the longitudinal direction arrow 12 and the transverse direction arrow 14 . The embodiment shown in FIG. 1 is a molded plastic clip 10 made of a resilient plastic material having a color selected to indicate the appropriate gauge of reinforcement bars upon which it may be installed. The clip 10 comprises a plurality of clasp assemblies. The embodiment shown in FIG. 1 comprises a pair of opposing first and second clasp assemblies 20 , 21 . Each first and second clasp assembly 20 , 21 is attached to parallel first and second longitudinal supports 16 , 18 and extends downward from the longitudinal supports 16 , 18 . The opposing first and second clasp assemblies 20 , 21 , together with the first and second longitudinal supports 16 , 18 , form a U-shaped profile, as is shown in FIG. 3 .
Referring again to FIG. 1 , the first and second clasp assemblies 20 , 21 each comprise an upper clasp 22 for holding a first reinforcement bar and a lower clasp 24 for holding a second reinforcement bars in a parallel orientation to the first reinforcement bar. For each first and second clasp assembly 20 , 21 , opposing, convexly curved fingers 34 extend upward from either end of a transverse support 26 so as to form the upper clasp 22 . One finger 34 a is shown attached to the first longitudinal support 16 and the opposing finger 34 b is shown attached to the second longitudinal support 18 . Together with the transverse support 26 , the opposing fingers 34 a , 34 b form an upper seat 32 . Referring now to FIGS. 1 , 2 and 4 , an upper clasp gap 42 is disposed between the first and second longitudinal supports 16 , 18 so as to provide a means of inserting the first reinforcement bar into the upper clasp 22 . The upper clasp gap 42 is selected so as to be narrower than the diameter of the first reinforcement bar, while the upper seat 32 is adapted in size and shape to compressively engage the first reinforcement bar when such bar is placed within the upper clasp 22 .
Referring again to FIG. 1 , for each first and second clasp assembly 20 , 21 , opposing, convexly curved fingers 34 c , 34 d extend downward from either end of the transverse support 26 so as to form the lower clasp 24 . Together with the transverse support 26 , the pair of opposing fingers 34 c , 34 d form a lower seat 30 . Referring now to FIGS. 1 , 2 and 4 , a lower clasp gap 40 is disposed between the opposing fingers 34 c , 34 d so as to provide a means of inserting a reinforcement bar into the lower clasp 24 . The lower clasp gap 40 is selected so as to be narrower than the diameter of the second reinforcement bar, while the lower seat 30 is adapted in size and shape to compressively engage the second reinforcement bar when such bar is placed within the lower clasp 24 .
The term ‘gauge of a clip’ is used herein to indicate the size of bar that the clip can attach and hold. In the preferred embodiment of the present invention, the gauge of the clip 10 is indicated by the color of the material used to fabricate the clip 10 . For example, a clip 10 having a red color may have a gauge of 0.425 inches and a clip 10 having a white color may have a gauge of 0.525 inches. Other color coding schemes would be obvious to one skilled in the skilled in the art. Optionally, the gauge of the clip is cast, printed or otherwise numerically indicated on the surface of the clip 10 . Preferably, the gauge of the clip is indicated by both color of the clip 10 and by the color of the material used to fabricate the clip 10 .
A preferred method of installing the clip 10 upon parallel oriented reinforcement bars is described. The gauge of the reinforcement bars is determined and the appropriate size of clip 10 is selected as indicated above. The receiver tip in the preferred embodiment of the application tool (not shown) is interchangeable and is selected by the gauge appropriate for installation into the upper clasp gap 42 . The clip 10 is removably installed upon the application tool by sliding the receiver tip into the upper clasp gap 42 so as to form a rigid assembly held together by a friction fit between the receiver tip and the first and second longitudinal supports 16 , 18 .
One novel aspect of the present invention is the flared guide 35 attached to the lower ends of each opposing finger 34 c , 34 d of the lower clasp 24 . During installation of the lower clasp 24 of the clip 10 upon a reinforcement bar 52 , each pair of flared guides 35 engage the bar 52 and guide it to the lower clasp gap 40 for insertion into the lower clasp 24 of each clasp assembly 20 , 21 . As the lower clasp 24 is pressed against the reinforcement bar 52 , the flaring of guides 35 cause the opposing fingers 34 c , 34 d to spread open so as to enlarge the lower clasp gap 40 sufficiently for the insertion of the bar 52 . After the bar 52 is inserted into the lower clasp 24 , the opposing fingers 34 c , 34 d close so as to hold the bar in the lower seat 30 .
Once the reinforcing bar 52 , is inserted into the lower clasp 24 , the receiver tip of the application tool 100 is removed from the upper clasp gap 42 . With the upper clasp gap 42 clear, another reinforcement bar 50 , is positioned above the upper clasp gap 42 and in a parallel orientation to the reinforcement bar 52 held in the lower clasp 24 . The bar 50 and the clip 10 are forced together so as to cause the opposing fingers 34 a , 34 b to spread open so as to enlarge the upper clasp gap 42 sufficiently for the insertion of the bar 50 . After the bar 50 is inserted into the upper clasp 22 , the opposing fingers 34 a , 34 b close so as to hold the bar in the upper seat 32 . In this configuration, the preferred embodiment of the clip 10 of the present invention holds the two reinforcement bars 50 , 52 independent of the other bar and a parallel orientation with the other bar as shown in FIG. 6 .
In an alternative preferred embodiment (not shown), flared guide 35 are attached to the upper ends of each opposing finger 34 a , 34 b and longitudinal supports 16 , 18 of the upper clasp 22 . During installation of the upper clasp 22 of the clip 10 upon a reinforcement bar 50 , each pair of flared guides 35 engage the bar 50 and guide it to the upper clasp gap 42 for insertion into the upper clasp 22 of each clasp assembly 20 , 21 in the same manner described above for the lower clasp 24 .
Referring to FIGS. 3 and 5 , an additional preferred embodiment is shown. In the embodiment shown, longitudinal supports 16 , 18 each cooperate with the opposed clamp assemblies 20 , 21 to form two aligned and opposing alternative upper clasps 23 . Each alternative upper clasp 23 includes an alternative upper seat 33 and an alternative upper clasp gap 44 . This additional preferred embodiment also includes upper and lower clasps 22 , 24 as previously described. In one application of this additional preferred embodiment, a first reinforcement bar is placed into the alternate upper clasps 23 by forcing the bar 50 into the alternate upper clasp gaps 44 and against the alternative upper seats 33 . A second reinforcement bar 52 is oriented in a position transverse to the first bar. The second bar 52 is then forced into the lower clasps 24 so as to contact the first bar 50 and to hold it against the alternative upper seats 33 . In the configuration shown in FIG. 5 , the clip 10 of this additional preferred embodiment attaches and holds two reinforcement bars 50 , 52 in a transverse orientation.
Advantageously, the clip 10 of this alternative preferred embodiment can selectively attach and hold two reinforcement bars 50 , 52 in either a parallel orientation, as described above, or in a transverse orientation as shown in FIG. 5 . This aspect of the invention allows a single type of clip to be used to attach adjacent reinforcing bars arranged in either a transverse orientation or in a parallel orientation.
Thus, although there have been described particular embodiments of the present invention of a new and useful Method of Attaching Reinforcing Bars, it is not intended that such references be construed as limitations upon the scope of this invention except as set forth in the following claims. | A system of attaching and aligning both parallel and transverse bars for supporting a concrete matrix includes a plurality of substantially identical molded plastic clips for alternatively attaching and holding two parallel reinforcing bars of equal diameter or two transverse reinforcing bars of equal diameter. | 4 |
FIELD OF THE INVENTION
The present invention relates to a transport system for transporting work pieces along a path, and a stopping mechanism for halting an electric mover guided automatically to move along a guide rail.
BACKGROUND OF THE INVENTION
Electric movers or cars in prior art transport systems of this type usually have wheels driven by electric motors and having a built-in brake. The brake not only increases the manufacturing cost of the system, but also makes it more complex to operate, more particularly the brake has to be deenergized whenever the electric mover is operated manually or is driven by an auxiliary conveyor. The brake of the electric mover has to be energized again when it is intended to stop moving.
Therefore, a need exists for a new type of transport system with a brakeless electric motor as its prime mover. The electric mover in this case must easily be controllable to stop at a given station or to stay sidelined. We have in the past proposed to meet these requirements by transport systems having a first and second stop switches to cut off the supply of power to each brakeless motor. The first switch is installed in a switchboard of a stopping mechanism and is manually operable to halt each electric mover at a given station. The second stop switch is provided on each electric mover whereby a member protruding rearwardly from a preceding electric mover actuates the second switch of a following mover when the latter approaches the former closer than a predetermined distance. The two stop switches and their accessories and their operation present various problems that complicate the transport system.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide an improved transport system comprising a plurality of electric movers each driven by a brakeless motor, and each electric mover can be easily stopped at a desired station and/or to stay sidelined.
The transport system of the present invention has at least one electric mover and a stopping mechanism, wherein each electric mover has a drive wheel, a brakeless motor for rotating the drive wheel, a photoelectric switch for deenergizing the brakeless motor, a contact member for stopping the electric mover, and a first detectable member which can be sensed and actuated to stop a following electric mover. A first photoelectric switch can cut off the supply of power to the brakeless motor. The first detectable member protrudes rearwardly from each electric mover and extends to a distance along the direction of travel of the mover. A second photoelectric switch on a following electric mover faces and senses the proximity of the first detectable member of the preceding electric mover, when the latter mover approaches the following mover closer than by predetermined distance.
The stopping mechanism at a desired stopping location, has a stopper for bearing against the contact member of the electric mover to be stopped, a second detectable member and a shifter. The shifter is operable to retracts the stopper and the second detectable member from their operating or stopping positions. The second detectable member extends to a distance in the travel direction. When this detectable member is shifted to its operative position, it faces the photoelectric switch, and can thus be sensed by it, before contact of the stopper with the contact member.
In the transport system of the present invention, a timer can be employed to resume supplying power to the brakeless motor after the passing of a predetermined time after the photoelectric switch stopped sensing. The second detectable member of the stopping mechanism which can face the photoelectric switch can be disposed at a level different than that of the first detectable member carried by the electric mover.
DESCRIPTION OF THE DRAWING
The invention is described in greater detail by reference being had to the drawing, wherein:
FIG. 1 is a side elevational view of a transport system of the present invention showing a guide rail in broken lines;
FIG. 2 is a front elevational view of the system of FIG. 1 with parts thereof being shown in cross section;
FIG. 3 is another side elevational view of the system of FIG. 1 showing a preceding electric mover halted by a following mover;
FIG. 4 is a plan view of portions of the electric movers shown in FIG. 3, with some parts shown in horizontal cross section;
FIG. 5 is a side elevational view of a mechanism for stopping the electric movers;
FIG. 6 is a front elevational view of an electric mover shown together with a positioning means of the stopping mechanism, with parts shown in cross section;
FIG. 7 is another front elevational view of the mover together with a stopper and a second detectable member, with some parts shown in cross section; and
FIG. 8 is a plan view of modified parts in the system.
DETAILED DESCRIPTION OF THE INVENTION
As shown in FIGS. 1 and 2, an electric mover 1 is guided for automatically advancing along a guide rail 2. The electric mover 1 includes a drive trolley 3 and an idler trolley 4, which are connected one to another by a loading bar 5. A hanging platform 6 depends from the loading bar 5 and supports and carries an article `W` to be transported.
The drive trolley 3 has a trolley body 7, a brakeless motor 8, a drive wheel 9, lateral rollers 10, and a collector 12. The trolley body 7 is disposed at one side of the guide rail 2, and the motor 8 having a speed reducer, is secured to a top of the trolley body 7. The drive wheel 9 that is connected to an output shaft 8a a of the motor rolls on an upper surface of the guide rail 2. The lateral rollers 10 are each journaled on a vertical shaft and are disposed on both sides of the guide rail. Top and bottom portions of the guide rail 2 are engaged by the lateral rollers to keep the trolley from rocking sideways, or from rocking forward and backward. The collector 12 is in sliding contact with electrical feeder wires 11 (see FIG. 2) extending along one side of the guide rail 2. The front end of the loading bar 5 is connected to a vertical shaft 13 hanging downward from the trolley body 7, and it is rockable sideways.
The idler trolley 4 has a trolley body 14 located at the one side of the guide rail 2, a freely rotatable wheel 16, and lateral rollers 17. The freely rotatable wheel 16 is adapted to roll on the upper surface of the guide rail 2 and is supported by a horizontal shaft 15 extending from a bearing which is secured to a top of the trolley body 14. The lateral rollers 17 are journaled on vertical shafts and are disposed on both sides of the guide rail. The top and bottom portions of the guide rail are contacted by the lateral rollers 17 to keep the idler trolley from rocking sideways or forward and backward. The rear end of the loading bar 5 is connected to a vertical shaft 18 depends from the trolley body 14 and is rockable sideways.
As best seen in FIGS. 3 and 4, the drive trolley 3 has a forward lug 19 protruding from a lower end of the trolley body 7 below the loading bar 5. A bumper 20 is attached to the forward end of the lug 19, which is the foremost end of the electric mover 1. Similarly, the idler trolley 4 has a rearward lug 21 protruding from a lower end of the trolley body 14, located below the loading bar 5. A bumper 22 is attached to the rearward end of the lug 21, which is the rearmost end of the electric mover 1.
A photoelectric switch 23 attached by a bracket 24 to the forward lug 19, serves to stop the electric mover. The photoelectric switch 23 is located above and beside the bumper 20, on the side thereof opposite to the trolley body 7. The switch 23 can open the power connection of the electric mover 1 for stopping its movement when the proximity of another object is sensed by the switch.
A contact member 25 is a rod extending sideways and outwardly from a portion of the loading bar 5, with the portion located behind photoelectric switch 23, and serves to halt the electric mover. A fan shaped first detectable member 26 is mounted by a bracket 27 from the rearward lug 21 below the bumper 22. The member 26 has a rearward extending width and projects from a preceding electric mover 6 be sensed by the photoelectric switch 23 of a following electric mover when it approached the preceding mover closer than by a predetermined distance.
FIGS. 5 to 7 show a stopping mechanism 28 located at a station where each electric mover 1 has to be temporarily halted. The stopping mechanism 28 has a stopper member 29, a second detectable member 30 to be sensed by the photoelectric switch 23, a shifter 31 and a positioner 32. The stopper 29 can bear against the contact member 25 of the electric mover to halt it in place. The shifter 31 shifts the stopper member 29 and the second detectable member 30 between their operative position depicted by the solid lines in FIGS. 5 and 7 and their nonoperative, retracted position shown in broken lines in FIG. 7.
The second detectable member 30 is formed integrally with or is attached to the lower end of a rockable arm 34. This arm 34 is swingable sideways about a shaft 33 which is disposed parallel to the direction of travel of the electric mover 1, shown by an arrow in FIG. 5. The second detectable member 30 takes its horizontal and operative position when the rockable arm 34 is vertically positioned. In that operative position the second detectable member 30 extends forwardly and rearwardly from the rockable arm 34 will vertically intervene between the photoelectric switch 23 of a following mover and the first detectable member 26 of a preceding mover.
The stopper member 29 is made of a shock absorbing rubber or the like material and is attached to a lower side surface of the rockable arm 34. This lower surface, which in an alternative mode may itself substitute for the stopper, faces the electric mover which approaches the stopper. The shifter 31 is a pneumatic cylinder interposed between a frame 35 and the rockable arm 34 pivoted therefrom by the shaft 33. The frame 35 secures the guide rail 2 to a support beam 37 disposed thereabove.
The positioner 32 as shown in FIGS. 5 and 6 has an auxiliary guide rail 38 extending parallel with the direction of travel of the electric movers, a chassis 40, a pusher 42 and a cylinder unit 43 for driving the pusher. The chassis 40 is supported by traction wheels 39 and is movable along the auxiliary guide rail 38. The pusher 42 is vertically pivoted from the chassis by a transversely disposed horizontal shaft 41. The pusher 42 in its lowered operative position shown in a solid line in FIG. 5 is adapted to press the contact member 25 of the electric mover 1 against the stopper 29 when the stopper is in its lowered operative position. The lowered working position of the pusher is the normal lowest position towards which it is always urged by gravity or a by a spring. A frame 44 which supports the auxiliary guide rail 38 also secures the main guide rail 2 to the support beam 37, retaining both guide rails below the support beam.
In operation of the transporting system described above, the collector 12 receives power from the electric feeder wires 11 to energize the motor 8 to rotation. The motor rotates the drive wheel 9 and thereby causes the electric mover 1 to travel along the main guide rail 2. As the electric mover 1 arrives at the station where the stopping mechanism 28 is located and the stopping of the mover at the station is desired, the shifter 31 lowers the rockable arm 36 with the second detectable member 30 thereon. As the mover approaches the station, the photoelectric switch 23 enters a space above the second detectable member 30. Upon detection of the second detectable member 30 by the photoelectric switch 23, the supply of electricity to the motor 8 is immediately cut off, thus making it freely rotatable. The electric mover 1 travels further by a small distance due to inertia, until coming into contact with or stopping short of the stopper member 29. During such an inertial forward movement, the photoelectric switch 23 on the mover 1 continues to sense the elongated second detectable member 30, continuing to keep open the electric power circuit of the motor 8.
Thus, the second detectable member 30 sensed by the photoelectric switch 30 opens the power circuit but does not cause any immediate contact between the contact member 25 and the stopper member 29. This is because the second detectable member 30 is of such a length that the mover 1 is allowed to move inertially until the contact member 25 contacts or stops short of the stopper member 29.
As shown in FIG. 5, the contact member 25 of the stopped mover 1 is located between the pusher 42 of the positioner 32 and the stopper member 29. This is because the contact member 25 temporarily swung the pusher 41 upwardly into its retracted position shown in broken lines by passing under the pusher before the mover 1 stops. Then the cylinder unit 43 drives the chassis 40 forward. The contact member 25 is contacted and pushed forward by the pusher 42 until the contact member is pressed against the stopper member 29 to halt the electric mover 1 at a predetermined position.
The cylinder unit 43 of the positioner 32 activates the pusher 42 to push the electric mover forward to the stop 29, when in the operative position of the stopping mechanism the arrival of the mover into the vicinity of the pusher 42 is detected. This can be accomplished by the provision of a detectable plate 45 on the mover 1 above the contact member 25. A photoelectric switch 46 mounted from the guide rail 2, swings down together with the rockable arm 34 for sensing the proximity of the contact member 25 and to actuate the cylinder unit 43 of the positioner 42.
In summary, the photoelectric switch 23 of each electric mover 1 does not only sense the second detectable member 30 of the stopping mechanism 28, but also senses the first detectable member 26 of a preceding electric mover. In each occasion of said sensing the electric switch 23 will stop the electric mover, when it sensed a detectable member 30 or 26. In that case the sensor switch 23 of a following mover 1 approaching the preceding mover 1 halted by the positioner 32, enters the space above the first detectable member 26 of the preceding mover as shown in FIGS. 3 and 4, and will thereby sense it. As a result, the power is cut off to the motor 8 that rotates the drive wheel 9 of the following mover 1. The motor 8 thus rendered freely rotatable will allow the following mover 1 to make an inertial forward movement up to a certain distance, until the forward bumper 20 of the succeeding mover contacts, or comes to a stop short of, the rearward bumper 22 of the preceding mover 1. During such an inertial movement, the photoelectric switch 23 in the following mover 1 continues to sense the first detectable member 2 of the preceding mover, so that the power circuit for the motor 8 continues to remain open.
The length of the first detectable member 26 is designed so that the rearward bumper 22 of the preceding mover will not immediately collide with the forward bumper 20 of the following mover when the photoelectric switch 23 cuts off the power when it senses the member 26 of the preceding mover. Thus, the inertial movement of the succeeding mover 1 continues until the forward bumper 22 collides with, or comes to a stop short of, the rearward bumper 20.
In this manner, following electric movers 1 will stop one after another automatically forming a row of movers with the leading mover 1 being stopped at the station by the stopping mechanism 28. When the leading mover 1 is to leave the station, the cylinder unit 36 pivots the rockable arm 34 upward about the shaft 33 so that the second detectable member 30 and the stopper member 29 in the stopping mechanism 28 are retracted to their nonoperative position. As the detectable member 30 is removed sideways from the space below the photoelectric switch 23, it stops sensing the presence of the detectable member 30 and the power circuit of the motor 8 is closed. The thus restarted motor 8 starts rotation of the drive wheel 9 and the leading mover 1 on its forward travel.
As the leading mover 1 travels forward, its first detectable member 26 is removed from the sensing range of the photoelectric switch 23 of the following electric mover. The power circuit of the motor 8 of the following electric mover starts to move it forward. The other following movers will similarly move forward one after another, until the foremost one of the following movers is stopped by the stopping mechanism 28.
The rockable arm 34 returns to its operative position to bring the detectable member 30 and the stopper member 29 into their operative positions shown in solid lines, when the departing leading mover's contact member 25 cleared the rockable arm 34. The switch 23 of the departing leading mover 1 which has moved forward no longer senses the second detectable member 30. The detectable plate 46 is no longer sensed by the additional photoelectric switch 45 when the contact member 25 has moved forward by a sufficient distance away from the rockable arm 34. In response to the non-sensing state of the additional switch 46, the cylinder unit 36 of the shifter 31 can return the detectable member 30 and stopper member 29 to their operative position.
When the second detectable member 30 and the stopper member 29 return to their operative position upon the departure of the leading mover 1, the first detectable member 26 of the departing electric mover passes by the station of the stopping mechanism 28. As this detectable member 26 moves along but below the operative second detectable member 30, there is no interference between those detectable members.
In an alternative mode, a timer 23a can be employed to delay the closing of power circuit for the motor 8 of the following mover, until the switch 23 advances of the preceding mover sufficiently so that it can no longer sense the detectable member 26. Thus the second detectable member 30 can return with the stopper member 29 to the operative position, after the first detectable member 26 of the departing mover has passed by them and before the succeeding photoelectric switch 23 arrives at the stopping mechanism. In this case, the second detectable member 30 can take its operative position also at the same level as the preceding detectable member 26.
The timer for resuming the delayed supply of power to the brakeless motor 8 after the change over of the switch 23 into its non-sensing state can also maintain a sufficient distance between preceding and following movers 1. This feature will be advantageous in that even if the travel path of the movers is curved and would increase resistance to the wheels 9 and 16 thereby decelerating the preceding mover 1, the following mover will not approach the preceding mover that its switch 23 would sense the detectable member 26 trailing from the preceding mover. Thus, a frequent starting and stopping of the following mover 1 at the entrance of the curved path region can be avoided.
In places such as an ascending path an auxiliary conveyor can be used to drive the movers 1 at a constant and probably lower speed. The electric wires 11 can be dispensed with to cut off power supply to the movers. The motor 8 will thus become idle to enable each mover 1 to be moved freely, so that for example a pusher of the auxiliary conveyor engages the contact member 25 and carries the mover forward at the desired constant speed. Power supply to any electric mover 1 can be cut off when maintenance work has to performed. The movers thus rendered idle can be moved manually during maintenance.
In the described embodiment, the pusher 42 of the positioner 32 is designed to press against the contact member 25 of the mover 1 to push it against the stopper member 29 in the stopping mechanism 28. As the rockable arm 34 could be subjected to considerable frictional resistance from the contact member 25 when the stopper member 29 is retracted into its nonoperative position.
FIG. 8 shows a suitable device to avoid such a problem. In this device, the stopper member 29 has a slanted face 29a such that an acute edge of the surface 47a thereof does lead an obtuse edge on the oblique surface 29a when the rockable arm swings, to thereby take a position nearer the contact member 25 than the obtuse edge does. Correspondingly, the contact member 25 has a lug with a slanted face 47a to come into surface contact with the corresponding oblique surface 29a of the stopper member 29. The slanted surface can be either formed on the contact member 25, or on a separate piece 47 attached thereto.
The full scope of the invention is defined by the following claims. | A transport system having (i) electrical movers for moving in a travel direction along a guide rail, each having (a) a drive wheel, (b) a brakeless electric motor for rotating the drive wheel, (c) a photoelectric switch adapted to sense the proximity of an object, (d) a contact member for stopping movement of the electric mover at a predetermined location, the photoelectric switch being disposed in the travel direction ahead of said contact member for switching the supply of electrical power to the motor upon sensing or ceasing to sense a previously sensed proximity of an object, and (ii) a stopping mechanism located along the guide rail for stopping the movement of an electric mover, including (a) a stopper adapted in an operative position thereof to stop a moving electrical mover by contact with the contact member, and to allow movement of the electrical mover when the stopper is not in its operative position, (b) a shifter for shifting the stopper in and out of its operating position, and (c) a detectable member shiftable by the shifter to a position perpendicularly to the travel direction when the detectable member is shifted to said perpendicular position, it can be sensed by the photoelectric switch before contact between the stopper and the contact member. | 8 |
RELATED U.S. APPLICATION DATA
This application is a division of U.S. patent application Ser. No. 10/569,147, filed on Feb. 21, 2006 now U.S. Pat No. 7,709,579 which is the national phase filing of International Patent Application No. PCT/US2004/25280, filed Aug. 5, 2004, which claims priority to U.S. patent application Ser. No. 10/642,325, filed on Aug. 18, 2003, the contents of all which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
Curable compositions, such as benzoxazine-based ones, are useful in applications within the aerospace industry, such as for example as a heat curable composition for use as a matrix resin in advanced processes, such as resin transfer molding, vacuum assisted transfer molding and resin film infusion, and their use in such advanced processes form the basis of the present invention.
2. Brief Description of Related Technology
Epoxy resins with various hardeners have been used extensively in the aerospace industry, both as adhesives and as matrix resins for use in prepreg assembly with a variety of substrates.
Blends of epoxy resins and benzoxazines are known. See e.g. U.S. Pat. No. 4,607,091 (Schreiber), U.S. Pat. No. 5,021,484 (Schreiber), U.S. Pat. No. 5,200,452 (Schreiber), and U.S. Pat. No. 5,445,911 (Schreiber). These blends appear to be potentially useful in the electronics industry as the epoxy resins can reduce the melt viscosity of benzoxazines allowing for the use of higher filler loading while maintaining a processable viscosity. However, epoxy resins oftentimes undesirably increase the temperature at which benzoxazines polymerize.
Ternary blends of epoxy resins, benzoxazines and phenolic resins are also known. See U.S. Pat. No. 6,207,786 (Ishida), and S. Rimdusit and H. Ishida, “Development of new class of electronic packaging materials based on ternary system of benzoxazine, epoxy, and phenolic resin,” Polymer, 41, 7941-49 (2000).
Resin transfer molding (“RTM”) is a process by which a resin—conventionally and predominately, epoxy-based resin systems and maleimide-based systems—is pumped at low viscosities and under pressure into a closed mold die set containing a preform of dry fabric. The resin infuses into the preform to make a fiber-reinforced composite article. The RTM process can be used to produce at low cost composite parts that are complex in shape. These parts typically require continuous fiber reinforcement along with inside mold line and outside mold line controlled surfaces.
Fiber-reinforced composite articles may be manufactured from vacuum assisted resin transfer molding (“VaRTM”), like RTM. In contrast to RTM, VaRTM employs an open mold and places the system under a vacuum to assist the resin infusion process.
Resin film infusion (“RFI”), like RTM, infuses a resin into a preform placed in a mold. Here, however, the resin is in the form of a film, which is placed in the mold together with the preform. U.S. Pat. No. 5,902,535 speaks to RFI molds and processes, and is expressly incorporated herein by reference.
The matrix resin used in the RTM and VaRTM advanced prossesses should desirably have a low injection viscosity to allow complete wetting and infusion of the preform.
Bismaleimide-based resins for RTM and RFI processes are known, and examples of which are described in U.S. Pat. Nos. 5,955,566 and 6,313,248.
And, two component epoxy resin compositions have been used, where the epoxy resin and the hardener components are combined immediately prior to use. One component epoxy resin compositions oftentimes must be stored at controlled low temperatures to prevent premature cross-linking reactions and to extend storage life. Otherwise, the viscosities of such one component epoxy resin compositions would build far too quickly, thus rendering their working life unsuitable (or at least not desirable) from a commercial standpoint.
Notwithstanding the state of the technology, there is a need for other resin systems to be used in these advanced processes, particularly a resin system with improved performance properties. And to date there has been no disclosure, teaching or suggestion to prepare a heat curable composition either as a matrix resin or in film form based on benzoxazine-containing compositions for these advanced processes.
SUMMARY OF THE INVENTION
The present invention relates to a process for producing composite articles in advanced processes, such as RTM, VaRTM and RFI systems, using a benzoxazine-containing heat curable composition.
The present invention thus provides in one aspect thereof a RTM process, steps of which include:
(a) providing a heat curable composition into a closed mold containing a preform;
(b) exposing the interior of the mold to a first elevated temperature and elevated pressure sufficient to wet the preform with the heat curable composition; and
(c) curing the heat curable composition-impregnated preform within the mold at a second elevated temperature to form a RTM product.
In another aspect, there is provided a VaRTM process, steps of which include:
providing a preform into a mold;
providing a heat curable composition into the mold under a first elevated temperature and under vacuum for a time sufficient to allow the composition to wet the preform; and
exposing the mold containing the composition wetted-preform to a second elevated temperature while under vacuum sufficient to cure the heat curable composition-wetted preform within the mold to form a VaRTM product.
In yet another aspect, there is provided a RFI process, steps of which include:
providing a preform into a closed mold containing a heat curable composition in film form;
exposing the interior of the mold to a first elevated temperature and optionally vacuum, while the exterior of the mold is exposed to an elevated pressure, for a time sufficient to infuse the preform with the heat curable composition; and
curing the heat curable composition-infused preform within the mold at a second elevated temperature to form a RFI product.
In each of these processes, the heat curable composition comprises (i) a benzoxazine component.
Of course, the invention provides products made by these advanced processes.
In still another aspect, the invention provides a binder composition, which is useful in both the RTM and VaRTM processes. The inventive binder composition is partially cured by exposure to elevated temperature conditions over time sufficient to increase the melting point higher than the temperature at which a matrix resin composition is to be infused into a preform and lower than the point at which the partially cured binder composition and the matrix resin composition are miscible.
The present invention will be more fully understood by a reading of the following detailed description of the invention.
DETAILED DESCRIPTION OF THE INVENTION
As noted above, provides in one aspect thereof a RTM process, steps of which include:
(a) providing a heat curable composition into a closed mold containing a preform;
(b) exposing the interior of the mold to a first elevated temperature and elevated pressure sufficient to wet the preform with the heat curable composition; and
(c) curing the heat curable composition-impregnated preform within the mold at a second elevated temperature to form a RTM product.
In another aspect, there is provided a VaRTM process, steps of which include:
(a) providing a preform into a mold;
(b) providing a heat curable composition into the mold under a first elevated temperature and under vacuum for a time sufficient to allow the composition to wet the preform; and
(c) exposing the mold containing the composition wetted-preform to a second elevated temperature while under vacuum sufficient to cure the heat curable composition-wetted preform within the mold to form a VaRTM product.
In yet another aspect, there is provided a RFI process, steps of which include:
(a) providing a preform into a closed mold containing a heat curable composition in film form;
(b) exposing the interior of the mold to a first elevated temperature and optionally vacuum, while the exterior of the mold is exposed to an elevated pressure, for a time sufficient to infuse the preform with the heat curable composition; and
(c) curing the heat curable composition-infused preform within the mold at a second elevated temperature to form a RFI product.
In each of these process the heat curable composition comprises (i) a benzoxazine component.
Of course, the invention provides products, such as RFI, RTM and VaRTM products, made by these advanced processes.
In still another aspect, the invention provides a binder composition, which is useful in both the RTM and VaRTM processes. The inventive binder composition is partially cured by exposure to elevated temperature conditions over time sufficient to increase the melting point higher than the temperature at which a matrix resin composition is to be infused into a preform and lower than the point at which the partially cured binder composition and the matrix resin composition are miscible.
Complex three dimensional part geometries may be molded in the advanced processes described herein as a single piece unit. RFI, for instance, is particularly useful for molding large composite parts, as it defines the entire geometry of the part in a single process cycle, thereby eliminating any subsequent assembly or bonding processes. In the aerospace industry, for one, it is not uncommon for parts to be up to 100 feet in length and up to 30 feet in width, located on lofted surfaces with integral stiffening and attachment details. Using these advanced processes to form such large parts, assembly and tooling costs normally associated with a mechanically fastened or bonded structure may be reduced. In addition, narrow engineering tolerances may be realized using these advanced processes to enable assembly of a large aircraft structure with minimal shimming, typically associated with non-monolithic components constructed from sub-assemblies.
In an RFI process, a resin film molding tool is ordinarily used, which includes an outer mold tool, which includes a facing sheet supported by a support structure. A resin film prepared from a benzoxazine is positioned on the facing sheet, and a preform is positioned on the resin film. The preform is designed in the shape of a desired article to be fabricated from compositing materials, such as fibers made from carbon, aramid, ceramic and the like. The preform may include a preform skin, as described in U.S. Pat. No. 5,281,388, the disclosure of which is hereby expressly incorporated herein by reference.
RTM systems are well known, such as those described in U.S. Pat. Nos. 5,369,192, 5,567,499, 5,677,048, 5,851,336, and 6,156,146, which are incorporated herein by reference. VaRTM systems are also well known, such as those described in U.S. Pat. Nos. 5,315,462, 5,480,603 and 5,439,635, which also expressly are incorporated herein by reference.
RTM systems produce composite articles from resin impregnated preforms. The preform is placed in a cavity mold. A benzoxazine-containing heat curable composition is then injected into the mold to wet and infuse the fibers of the preform. In an RTM process, the benzoxazine-containing heat curable composition is introduced into the cavity mold under pressure. The benzoxazine-containing heat curable composition-infused preform is cured under elevated temperature. The resulting solid article may be subjected to post curing operations to produce a final composite article, though this is not required.
Thus, with the RTM process, the preform is placed, within the mold. The preform used in the RTM process may include a benzoxazine-containing heat curable binder composition, tacked to the fibers which make up the preform.
In an RTM process, therefore, the mold is then closed and the benzoxazine-containing heat curable composition is introduced, and allowed to infuse the preform. This introduction may occur under mildly elevated temperature conditions to improve flow characteristics of the benzoxazine-containing heat curable composition for a time sufficient to allow wetting of the preform.
The interior of the mold is then heated to and maintained at, a temperature (ordinarily within the range of 250° F. to 350° F.) which is sufficient to cure the benzoxazine-containing heat curable composition, for a time sufficient to cure the heat curable composition. This time is ordinarily within the 60 to 180 minute range, depending of course on the precise constituents of the heat curable composition. After cure is complete, the temperature of the mold is allowed to cool and the RTM product made by the process is removed.
In a VaRTM process, after providing the preform, a dispersing medium may be disposed thereover. The dispersing medium is positioned on the surface of prefrom in an envelope within the mold. The dispersing medium is oftentimes an open weave fabric. The vacuum is applied to collapse the dispersing medium against the preform and assist in the introduction of the benzoxazine-containing heat curable composition into the mold to wet and infuse the preform.
The benzoxazine-containing heat curable composition is injected into the mold, and allowed to wet and infuse the preform. This injection may again occur under a mildly elevated temperature, this time through and under vacuum for a period of time sufficient to allow the composition to wet and infuse the preform.
The benzoxazine-containing heat curable composition is introduced under vacuum into the envelope to wet and infuse the preform. The vacuum is applied to the interior of the envelope via a vacuum line to collapse the flexible sheet against the preform. The vacuum draws the benzoxazine-containing heat curable composition through the preform and helps to avoid the formation of air bubbles or voids in the finished article. The benzoxazine-containing heat curable composition cures while being subjected to the vacuum.
The mold is then exposed to an elevated temperature, ordinarily within the range at 250° F. to 350° F., while remaining under vacuum, for a period of time sufficient to cure the heat curable composition-wetted preform within the mold. This time period again is ordinarily within the 60 to 180 minute range. The vacuum also draws off any fumes produced during the curing process. After cure is complete, the temperature of the mold is allowed to cool and the VaRTM product made by the process is removed.
For these advanced processes, the benzoxazine-containing heat curable composition has a viscosity in the range of 10 to 5000 cps at resin injection temperature (10 to 3000 cps for RTM or VaRTM; 10-5000 cps for RFI). In addition, the time within which the viscosity of the heat curable composition increases by 100% under the process conditions is in the range of 1 to 10 hours.
The resulting solid article so made by the VaRTM process may be subjected to post curing operations to produce a final composite article.
The first step in either of the RTM/VaRTM processes is thus to fabricate a fiber preform in the shape of the desired article. The preform generally includes a number of fabric layers or plies made from these fibers that impart the desired reinforcing properties to a resulting composite article. Once the fiber preform has been fabricated, the preform is placed in a mold.
The benzoxazine of the heat curable composition may be embraced by the following structure:
where o is 1-4, X is selected from a direct bond (when o is 2), alkyl (when o is 1), alkylene (when o is 2-4), carbonyl (when o is 2), thiol (when o is 1), thioether (when o is 2), sulfoxide (when o is 2), and sulfone (when o is 2), R 1 is selected from hydrogen, alkyl, alkenyl and aryl, and R 4 is selected from hydrogen, halogen, alkyl and alkenyl.
More specifically, the benzoxazine may be embraced by the following structure:
where X is selected from of a direct bond, CH 2 , C(CH 3 ) 2 , C═O, S, S═O and O═S═O, R 1 and R 2 are the same or different and are selected from hydrogen, alkyl, such as methyl, ethyl, propyls and butyls, alkenyl, such as allyl, and aryl and R 4 are the same or different and are selected from hydrogen or allyl.
Representative benzoxazines include:
where R 1 , R 2 and R 4 are as defined above.
Alternatively, the benzoxazine may be embraced by the following structure:
where p is 1-4, Y is selected from the group consisting of biphenyl (when p is 2), diphenyl methane (when p is 2) and derivatives thereof (such as alkylated diphenyl methanes like tetra methyl, tetra ethyl, tetra isopropyl, dimethyl/diethyl and the like), diphenyl ethyl (when p is 2), diphenyl isopropane (when p is 2), diphenyl sulfide (when p is 2), diphenyl sulfoxide(when p is 2), diphenyl sulfone (when p is 2), and diphenyl ketone (when p is 2), and R 4 is selected from hydrogen, halogen, alkyl and alkenyl.
Though not embraced by structures I, II or III additional benzoxazines are within the following structures:
where R 1 , R 2 and R 4 are as defined above, and R 3 is defined as R 1 R 2 or R 4 .
Examples of these benzoxazines therefore include:
The benzoxazine component may include the combination of multifunctional benzoxazines and monofunctional benzoxazines. Examples of monofunctional benzoxazines may be embraced by the following structure:
where R is alkyl, such as methyl, ethyl, propyls and butyls, or aryl, and R 4 is selected from hydrogen, halogen, alkyl and alkenyl.
Eamples of such a monofunctional benzoxazine are:
The benzoxazine component should be present in an amount in the range of about 10 to about 99 percent by weight, such as about 25 to about 75 percent by weight, desirably about 35 to about 65 percent by weight, based on the total weight of the composition. In the event that a monofunctional benzoxazine is present as well, the monofunctional benzoxazine may be present in an amount in the range of about 0 to about 90 percent by weight, such as about 10 to about 80 percent by weight, more desirably about 25 to about 60 percent by weight, based on the total weight of the benzoxazine component—that is, the monofunctional benzoxazine and multifunctional benzoxazine.
In one version of the heat curable composition, the benzoxazine component may also include (ii) a toughener component comprising acrylonitrile-butadiene co-polymer having secondary amine terminal groups.
This toughener component should be present in an amount in the range of about 1 to about 90 percent by weight, such as about 10 to about 70 percent by weight, desirably about 15 to about 30 percent by weight, based on the total weight of the composition.
In another version of the heat curable composition; the benzoxazine component may also include
(ii) an epoxy or episulfide component; (iii) optionally, one or more of an oxazoline component, a cyanate ester component, a phenolic component, and a thiophenolic component; (iv) optionally, acrylonitrile-butadiene co-polymer, a polyimide component, and a polyimide/siloxane component; and (v) optionally, a curative.
The epoxy or episulfide component should be present in an amount in the range of about 5 to about 60 percent by weight, such as about 10 to about 50 percent by weight, desirably about 15 to about 35 percent by weight, based on the total weight of the composition.
The oxazoline component, the cyanate ester component, the phenolic component, and the thiophenolic component should be present in an amount in the range of about 5 to about 60 percent by weight, such as about 10 to about 50 percent by weight, desirably about 15 to about 35 percent by weight, based on the total weight of the composition.
The acrylonitrile-butadiene co-polymer, polyimide component, and the polyimide/siloxane component should be present in an amount in the range of about 1 to about 50 percent by weight, such as about 5 to about 35 percent by weight, desirably about 10 to about 25 percent by weight, based on the total weight of the composition.
The curative should be present in an amount in the range of about 0.01 to about 40 percent by weight, such as about 0.5 to about 20 percent by weight, desirably about 1 to about 15. percent by weight, based on the total weight of the composition.
The binder composition, which may be used in the RTM or VaRTM process, includes a solid benzoxazine component, which is partially cured by exposure to elevated temperature conditions over time sufficient to increase the melting point higher than the temperature at which a matrix resin composition is to be infused into a preform and lower than the point at which the partially cured binder composition and the heat curable composition are miscible. The binder composition may also include a spacer selected from particles constructed of thermoplastics, rubbers, metals, carbon, core shell, ceramics and combinations thereof.
Like the heat curable composition, the binder composition may include a toughener component comprising an acrylonitrile-butadiene co-polymer component (such as acrylonitrile-butadiene co-polymer having secondary amine terminal groups), polyimide component, and a polyimide/siloxane component; and/or an optional, epoxy resin or episulfide resin component; an optional, one or more of an oxazoline component, a cyanate ester component, a phenolic component, and a thiophenolic component; and an optional curative.
EXAMPLES
Example 1
In this example, a formulation suitable for use as a thick film in an RFI process (such as 0.20 pounds/ft 2 areal weight or 30 mils thickness), or as a resin for VaRTM and RTM is illustrated.
The formulation included an approximate 1:1 mixture of benzoxazines based on bisphenol F and thiodiphenol at a 68 weight percent; cycloaliphatic epoxy resin (CY 179, commercially available from Vantico) at a 23 weight percent; and ATBN (1300X16, commercially available from Noveon, Cleveland, Ohio) at a 9 weight percent, based on the total formulation. The components can be added to one another in any convenient order, and mixed at room temperature for a time sufficient to generate a substantially homogenous mixture.
The formulation so formed may be used in an RTM process, for instance, as follows:
Preheat the formulation to a temperature of 160° F. Insert a preform into a closed mold Preheat the mold to a temperature of 250° F. Apply vacuum to the mold for a period of time of 1 hour to remove any volatiles from the preform Preheat resin injector to a temperature of 235° F. Add the preheated formulation to the injector When the formulation equilibrates at a temperature of 250° F., apply full vacuum for a period of time of 15 minutes to remove air Release the vacuum Inject the formulation at about the rate of 5 to 200 cc per minute using about 20 psi injection pressure, which may be increased, if desired throughout the injection to maintain the desired flow rate When the preform is fully impregnated, close the mold resin exit ports Pressurize the tool to 100 psi and hold at that pressure for a period of time of about 10 minutes Ramp the mold temperature to 350° F. at 3° F. per minute When the formulation has gelled, remove the applied pressure Hold the temperature at 350° F. for a period of time of 3 hours Cool to a temperature of 120° F. Open the mold and remove the cured part.
The properties of the so formed cured part in the form of a panel were observed as follows using Toray T-300 3K 70 plain weave woven carbon fabric:
Glass transition temperature, hot/wet, ° F.
354
Open hole compressive strength @ 75° F., ksi
43
Open hole compressive modulus @ 75° F., msi
7.1
Open hole compressive @ 180° F., wet, ° F.
36
Compression after impact @ 75° F., ksi
33
Example 2
In this example, a formulation was prepared from an approximate 60:40 mixture of bifunctional benzoxazine and monofunctional benzoxazine, each based on formaldehyde, phenol and aniline at a 75 weight percent, and cycloaliphatic epoxy resin (CY 179) at a 25 weight percent, based on the total formulation. As in Example 1, the components can be added to one another in any convenient order. Here, however, the components were mixed at an elevated termperature in the range of 160° F. to 180° F. for a time sufficient to generate a substantially homogenous mixture.
The formulation so formed may be used in an RTM, with a injection temperature in the range of from 180° F. to 250° F., with an injection window of at least 4 hours. The formulation can be cured at a temperature of 350° F. for a period of time of 2 hours.
The properties of the so formed cured part in the form of a panel were observed as follows using Cramer 445 Fabric, and conditioned as noted:
Property
Conditioning
Test Conditions
Values
ILSS (Mpa)
MEK/RT/1 h
RT
60
Water/100° C./2 h
70° C.
68
Dry
RT
60
Dry
120° C.
60
70° C./85% RH
70° C.
68
T g , onset (° C.)
Dry
N/A
190
70° C./85% RH
N/A
170
IPS strength (Mpa)
Dry
RT
112
IPS modulus (Gpa)
Dry
RT
4.9
CAI (Mpa)
Dry
RT
227
Here, ILSS is interlaminar sheer strength, MEK is methyl ethyl ketone and CAI is compression after impact. | Curable compositions, such as benzoxazine-based ones, are useful in applications within the aerospace industry, such as for example as a heat curable composition for use as a matrix resin in advanced processes, such as resin transfer molding, vacuum assisted transfer molding and resin film infusion, and their use in such advanced processes form the basis of the present invention. | 8 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to systems and methods for utilization of solar energy. More particularly, it concerns improvements in collection efficiency of solar energy collection systems by heating gas and liquid streams in controlled manner at the same time.
2. Description of the Prior Art
A great amount of study and work has been devoted in the past to solar energy utilization and, as the cost of fossil fuel has increased, the pace of such study and work has increased. Nevertheless, the relatively high cost of solar energy equipment per energy unit usefully delivered has been a serious deterent to its widescale use. Equipment costs and improvement in its collection efficiency would serve to increase demand for and use of solar energy systems.
The present inventor has previously patented a solar energy system using improved solar heat collectors to supply reaction heat in conducting continuous chemical processes, e.g., manufacture of methane gas (see U.S. Pat. No 4,057,401).
Solar collectors have, of course, been used to heat gas alone (see U.S. Pat. No. 4,016,860) or liquid alone (see U.S. Pat. No. 4,082,081). Also, there are numerous solar heaters that use heated air for heat exchange with liquid to provide heated liquid or, the reverse, heated liquid to provide heated air (see U.S. Pat. Nos. 3,250,269; 3,875,925; 3,919,998 and 3,960,136).
Notwithstanding the extensive research and development directed to solar energy collection, there exists a continuing need for improvements in efficiency of such operation and reduction in the cost of equipment used therewith.
OBJECTS
A principal object of this invention is the provision of new systems and methods for solar energy collection.
Another object is the provision of improvements in solar energy collection to obtain high energy collection efficiency and reduce the cost per unit of energy rendered usefully available in such collection operations.
A further object is the provision of a solar energy collector that heats gas and liquid at the same time and increases the BTUs obtained per square foot of collecting area.
Other objects and further scope of applicability of the present invention will become apparent from the detailed description given hereinafter; it should be understood, however, that the detailed description, while indicating preferred embodiments of the invention, is given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
SUMMARY OF THE INVENTION
The objects of the invention are accomplished by constructing a solar energy collector system to enable sun rays radiated upon the collector to simultaneously heat separate gas and liquid streams pumped through the collector and to regulate exposure times of the gas and liquid within the collector automatically by separate thermostatic controls. A gas passageway is provided sunward of the liquid passage which is in direct heat exchange with an opaque panel of heat conductive material positioned in the gas-tight chamber of the collector defined by a insulated housing and a pair of spaced apart covers formed of transparent material. The gas passageway is located below the two covers and is tiered by central screen means that intercepts a portion of the sun rays entering the collector while allowing the remaining rays to heat the opaque panel on the shadow side of the screen means. Shutter means is provided to move between the first and second transparent covers to shade the screen means, passageways and panel from sunrays radiating on the collector and there is means automatically to operate the shutter means dependent upon the temperature existing in the collector chamber.
BRIEF DESCRIPTION OF THE DRAWINGS
A more complete understanding of the invention may be had by reference to the accompanying drawings in which:
FIG. 1 is diagrammatic lateral view of a solar heat collector system of the invention.
FIG. 2 is a lateral sectional view of a solar heat collector of the invention.
FIG. 3 is a sectional view taken on the line 3--3 of FIG. 2.
FIG. 4 is fragmentary plan view of the solar heat collector of FIG. 2.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring in detail to the drawings, the collector system 2 basically comprises collector means 4, reflector means 6, gas conduit means 8, liquid conduit means 10, liquid storage means 12 and external heat exchange means 14.
The collector means 4 comprises a quadrangular housing 16 formed of heat insulation material and a first transparent cover 18 having a flat surface portion 20, dependent end portions 22 and dependent side portions 24. The end portions 22 are sealed to the ends 26 of housing 16 by the contoured strips 28 fixed to the ends 26 by fasteners (not shown). Similarly, side portions 24 are sealed to the sides 30 of housing 16 by contoured strips 32 fixed to the sides 30 by fasteners (not shown). Accordingly, the cover 18 forms an air-tight chamber 34 over the housing 16.
A second transparent cover 36 having a flat surface portion 38, dependent end portions 40 and dependent side portions 42 is positioned within chamber 34 with portion 38 spaced apart and substantially parallel to portion 20 of cover 18 providing therebetween a space 44. The angled tip 46 of portion 42 is held upon the ledge portion 48 of housing 16 by contoured strip 50 while the angled tip 52 of portion 40 rests on ledge portion 54 of housing 16.
A rod or wire frame 56 provides support and rigidity to the cover 18 and, likewise the frame 58 strengthens the cover 36.
Screen means 60 is stretched substantially parallel to the cover 36 across the chamber 34 between the angle members 62 forming a gas passageway 64 between cover 36 and screen means 60.
The screen means 60 intercepts a portion of the sun rays passing through covers 18 and 36 causing the passageway 64 to be heated. It may be formed, for example, of a single layer of woven metal screening. Advantageously, however, the means 60 is made of two layers 66 and 68 of metal screening with the surface of layer 68 opposite the cover 36 being light reflective and the other three surfaces of layers 66 and 68 being light absorptive. This can be attained by making layers 66 and 68 of woven aluminum screen with the top and bottom surfaces of layer 66 and top surface of layer 68 being coated with light absorptive material, e.g., matt-finish black paint while leaving the bottom surface of layer 68 uncoated.
An opaque panel 70 is positioned within the chamber 34 substantially parallel to the screen means 60 and spaced apart therefrom forming a longitudinal passageway 72 between means 60 and panel 70. The panel may be formed of any heat conductive material, e.g., aluminum, copper or steel sheet or plate.
Tubing 74 is positioned in direct heat-exchange contact with the panel 70, e.g., by welding the tubing to the panel. The tubing can be of any desired cross-section, e.g., circular, square, elliptical, etc. and formed of any suitable heat-conductive material, e.g., copper, aluminum etc. Alternatively, the combination of panel 70 and tubing 74 may be replaced with a pair of metal plates stamped and welded together to form a liquid conduit equivalent to the tubing 74.
The tubing 74 is contiguous with a liquid inlet 76 that enters into the chamber 34 through the base 78 of the housing 16 and a liquid outlet 80 that exits through the housing base 78. A pressure relief valve 82 may be included in the tubing line 74 to prevent the pressure in the line from exceeding a predetermined maximum.
A corrugated sheet 84, e.g., stamped from metal or other heat conductive material, serves to support the panel 70 and tubing 74 spaced above the base 78 of housing 16. The sheet 84 also creates a gas passageway 86 below the panel 70 and the housing base 78.
A gas inlet 88 extends through the housing 16 and into the gas passageway 64. A manifold 90 fitted to the exhaust end 92 of inlet 88 serves to distribute gas from inlet 88 evenly across the width of passageway 64.
The downstream end 94 of passageway 64 joins the upstream end 96 of passageway 72 so gas flows, as indicated by the arrows in FIG. 2, from inlet 88 along passageway 64 and then passageway 72 until baffle 98 directs it into the gas outlet 100 which extends through the housing 16. Gas also flows from gas passageway 64 through passageway 86 below the panel 70 to exit through the gas outlet 100.
Although the gas flow as described above is preferred, other arrangements may be used. For example, the forced gas may enter the top and return to the top of the collector or from the bottom and return to the bottom, or from the right or left side and return to the same or other side. In any of these arrangements, the gas stream after being heated in the collector means 2 can be conveyed by conduit means 8 to the heat exchange means 14 and recycled to the collector means 2 and/or conveyed to storage (not shown). The conduit means 8 can comprise exhaust pipe 102, return pipe 104 and gas blower 106.
The liquid conduit means 10 comprises a line 108 leading from a liquid source and a pump 110 that delivers liquid under pressure to the liquid inlet 76. The liquid outlet line 80 leads to the storage means 12 comprising small, insulated storage tank 110, intermediate size tank 112 and large size tank 114. The inlet pipes 116, 118 and 120 to tanks 110, 112 and 114 respectively, include control valves 122. Similarly, the exit lines 124, 126 and 128 from tanks 110, 112 and 114 respectively, include control valves 130, and connect to a common line 132.
The liquid supplied through line 108 may be water, water containing antifreeze, brine or any other suitable liquid. It may be derived from a primary source (not shown) such as a water main or may be the whole or any part of the liquid which flows out of storage means 12 via line 132.
Two tanks, e.g., 110 and 114, may be used or, alternatively, more than three tanks may be used. Regardless of number, the tanks should be heat insulated and advantageously placed under ground. Also they are graduated in size. As the temperature of liquid in the storage tank 110 reaches a predetermined level, e.g., 180°-200° F., differential thermostats (not shown) controlling valves 122 will operate to switch liquid flow from line 80 from tank 110 to tank 112 and then from 112 to 114. Liquid is pumped from tank 110 last, i.e., if all tanks are at the same predetermined temperature, use of heated liquid will begin from the largest tank 114 until its temperature drops to a predetermined level, e.g., 175° F. Then, a differential thermostat will operate control valve 130 of tank 114 to cut off flow from tank 114 and starts flow from tank 112, etc.
The rate of flow of liquid into the collector 4 via line 76 is controlled by thermostatic means 134 which comprises a throttle valve 136 regulated by a thermostat (not shown) which may be attached to panel 70 or inserted in tubing 74. Also, the rate of flow of gas into the collector 4 via line 88 is controlled by thermostatic means 138 which comprises a throttle valve 140 regulated by a thermostat (not shown) which may be positioned in the passageway 64 or other desired position in chamber 34.
The amount of heat, i.e., BTUs, absorbed by the gas and liquid flowing in the collector 4 from the sun rays is in direct relation to the exposure time (distance travelled in collector/flow rate). The temperature of liquid and gas is controlled, in part, by controlling the flow rate. To obtain the maximum amount of heat, the new collection methods automatically increase or decrease the flow rates thermostatically. The gas flow rate may be controlled by thermostatically increasing or decreasing the speed of the gas blower 106 or by controlled opening or closing of the throttle valve 140. The liquid flow rate may be controlled by thermostatically increasing or decreasing the speed of the pump 100 or by controlled opening and closing thermostatically the throttle valve 136. The thermostatic sensors (not shown) that form part of the thermostatic means 134 and 148 may be located at any suitable place in the collector 4 or in the conduit means 10 and 8 respectively.
The collector 4 is provided with shutter means 142 to shade the chamber 34 and the various elements contained therein for sun rays. The shutter means is automatically operated by latch means 144 in response to the temperature that may exist in chamber 34. For example, the shutter means automatically shuts off sunlight to the screen means 60 in case of an electrical power failure that would stop the running of pump 110 and blower 106. When the pump or the blower is off, during a clear or a high sun ray absorption time, the sun collector temperature can raise to 400° F. or more, when there is no liquid or gas flow through the sun collector system. If temperature raises about the setting or the pressure relief valve 82, the valve will open--this will allow the liquid in the tube system to escape. If antifreeze or a refrigerant is used in the liquid system, it will require replacement at an added expense or material and labor, when liquid is released by the relief valve.
The shutter means 142 is in between the transparent covers 18 and 36, closing over the cover 36 to prevent a high temperature buildup. Also, thermostatically, the blower and pump will be turned off when the temperature is in the sun collector drops below a predetermined temperature and, would also be turned on at a predetermined raise in temperature. This low temperature turn off will close the shutter means 142 over the inner cover 36 which helps to keep in the heat already in the collector.
The shutter means 142 comprises a roller 146 carried in bearing 148 biased by an internal spring (not shown) to rotate so as to wind the cords or cables 150 onto the roller 146. The cables 150 are connected at the unwound end to the flexible, opaque web 152 which rolls around the roller 154 carried by bearing 156. The web is made of cloth, non-woven fabric or the like and preferably has light reflective surfaces. The roller 154 is rotated by the motor 158 and reduction drive 160.
The latch means 144 is advantageously a magnetic brake which is turned on by a limit switch (not shown) that turns off motor 158 when the shutter web 152 is fully wound onto the roller 154. The energized brake 144 holds the roller and web from unwinding, but if there is a power failure, the brake will be de-energized and allow the roller 154 to move so cable 150 will wind onto roller 146 and draw web 152 across the collector to roller 146 shutting off sun rays from entering the collector. This interior roll-up type of shutter means is advantageously used to protect the collector against overheating.
The reflector means 6 comprises a quadrangular sheet 162 having dependent side portions 164. It is pivoted at one end upon spring-biased hinges 166 that urge reflector means 6 toward a closed position covering the collector (see FIG. 3). The reflector means 6 is moved into the open position (see FIG. 1) where it will reflect sun rays into the collector 4 by cable 168 which is fastened at end 170 to sheet 162. The cable 168 passes over the pulley 172 to the motor drive 174.
Sun rays are enhanced up to 40 percent by using the reflective means 6. The panel is attached to bottom of collector housing by a spring loaded hinge 166 set at an open angle of about 110° between collector housing surface and the reflective panel. The sun rays are bounced or reflected from the reflective means 6 through the transparent cover of collector at the same time that the sun rays are received directly through the transparent covers to obtain the maximum energy yield. The hinged reflective means 6 has a spring attached to hinges 166 which holds the hinge in a normal closed position. The closed position covers up the transparent cover on the collector if electrical power should fail. If reception was high, means 6 can also prevent damage to the collector from overheating. The reflective means 6 can close up when heat reception is too low (using a preset temperature remote control thermostat (not shown) that opens the circuit to magnetic brake 176 which holds the reflective panel in down (open) position. This allows the spring tension to raise panel, closing the front of collector, also, turning off the fluid pump and gas blower.
Closing the face of the collector helps to retain the heat which is in the collector and housing unit. The spring pressure in hinges 166 will close and hold the means 6 closed when power is off. When electrical power comes back on, or temperature in the collector is above a predetermined setting, the reflective panel is pulled down to its normal open position by the flexible cables 168 which are rolled up by the small electrical motor unit 174. When the reflective means reaches a predetermined down (or open) position, the sheet 162 operates the limit switch 178. In the reflection position, the switch 178 turns off the electrical motor and turns on the magnetic brake, holding sheet 162 down (open).
The collector 4 is pivoted at one side upon the standard 180 and adjustable support means 182 is connected to the housing 16 to permit the collector the be fixed at varied angles about the standard 180 relative to the horizon.
A pressure relief valve 183 may be fitted in the housing 16 to prevent damage to the collector 4 due to excessive gas pressure build-up in the chamber 34.
Gas is heated by the sun rays coming in through the two transparent covers 18 and 36, then passing over screens 66 and 68 heating the gas twice, once when the gas is forced over the upper screen and, when it returns behind bottom screen. The gas also flows in front of and in back of collector panel 70 with liquid tubes attached. The sun rays pass through the screens and are absorbed by the panel 70 in back of screens with liquid tubes attached; thus, heating both gas and liquid at the same time.
The two screens 66 and 68 are close together and both have an open space at the same end. The top screen is treated as previously stated, with a heat absorbing coating on both sides. The bottom screen is treated with the same heat absorbing coating, only on the top side of the bottom screen. The under side of the bottom screen is reflective, to help hold the heat rays inward that have been received from the sun for greater heat absorption. It is necessary to maintain an average temperature between 170° F. and 200° F. to furnish the required heat for a heat absorption air-conditioning system.
As can be seen by reference to FIGS. 2 and 3, the level of the screen means 60 and the panel 70 is above the top surface of ledge portion 48 of housing 16. This brings them on a level with transparent sides 24 and 42, etc. of the transparent covers 18 and 36 so the means 60 and panel 70 will obtain maximum exposure to sun rays, i.e., shadowing of them by housing 16 early and late in the day is eliminated.
The heated gas can be used to heat liquid by passing the heated gas through a heat exchanger. Also, the heated liquid can be used to heat gas by passing the heated liquid through a heat exchanger; thus, supplying the maximum amount of heated gas or heated liquid which different systems may require.
Where air-conditioning is needed, more than space heating, more heated liquid will be required. When the need for space heating is greater, either gas heating or liquid heating can be used for the space heating. It is also possible to use both heated gas and heated liquid for space heating, air-conditioning and hot water at the same time. | A solar energy collector system having high energy collection efficiency simultaneously heats separate gas and liquid streams flowing through the collector. The gas flows in a tiered passage sunward of the liquid passage. Exposure times of gas and liquid are regulated by separate thermostatic controls. The heated gas and liquid may be used as energy imput for space heating, hot water, air conditioning, etc., separately or in combination. | 5 |
BACKGROUND OF THE INVENTION
1) Field of the Invention
The present invention relates to brassieres. The invention relates more particularly to brassieres including non-underwire and underwire brassieres, and blanks and methods for making such brassieres, wherein the blanks are formed from circularly knit fabric tubes.
2) Description of the Related Art
Brassieres are generally designed to provide support, shaping, and separation of the wearer's breasts. Conventionally, brassieres for larger-breasted women often include underwires extending along the lower margins of the breast cups. Underwires provide a level of stability, or at least the perception of stability, that fabric alone generally cannot provide, in part because fabric cannot support compressive forces the way underwires can. Typically, brassieres are fashioned in a cut-and-sew manner, as exemplified for instance in U.S. Pat. No. 4,372,312. A brassiere made in this manner may consist of more than a dozen separate fabric pieces sewn together. One advantage of the cut-and-sew method is that different areas of the brassiere can be given different properties, since the various fabric pieces can be of different knits, different yarns, etc. It may be advantageous, for example, to make some portions of the brassiere resiliently stretchable to hug the wearer's body, while other portions are relatively unstretchable for greater stability.
The cut-and-sew method, however, is disadvantageous in that it entails a great number of cutting and sewing operations. Accordingly, methods of fashioning brassieres from circularly knit fabrics have been developed in an effort to improve the speed and efficiency of production. For example, commonly assigned U.S. Pat. Nos. 5,479,791 and 5,592,826 disclose methods for making non-underwire brassieres from circularly knit tubular blanks. The brassieres are made from single-ply tubular blanks that have a turned welt at one end to form a torso portion of the brassiere. A series of courses for defining breast cups and front and rear shoulder straps are integrally knit to the turned welt. The brassiere requires sewing only for joining the front and rear shoulder straps to each other. The '826 patent discloses modifying the knit structure along outer edges of the breast cups nearest the wearer's arms to form panels having a greater resistance to coursewise stretching than the remainder of the fabric blank. The relatively unstretchable panels provide increased lift and support.
U.S. Pat. No. 6,287,168 overcomes some of the aforementioned problems by providing a brassiere formed from a circularly knit fabric tube 50 , as shown in FIGS. 2 and 3 of the '168 patent. The blank is knit to have two pairs of breast cups 24 , torso encircling portions 26 and central panels 28 that are arranged in mirror image about a fold region 56 along which the blank is folded so that the cups, torso encircling portions and central panels overlap and form a two-ply structure. Advantageously, the central panel can be knit to have greater resistance to stretching than the cups and torso encircling portions for an effect similar to cut-and-sew brassieres but without seams for additional wearer comfort. Despite the minimal seams, however, the brassiere still requires the use of elastic banding 46 to secure the edges of the overlapping material together, as shown in FIG. 1 of the '168 patent. Elastic banding has the aesthetic drawback in that it can sometimes show through a blouse. In addition, elastic banding, depending upon its location, can reduce wearer comfort.
Therefore, it would be advantageous to have a brassiere that provides adequate and comfortable support for the wearer while at the same time reducing the use of elastic banding and seams. It would be further advantageous if the brassiere were constructed of a circular knit fabric tube to minimize the amount of cutting and stitching necessary to construct the brassiere.
BRIEF SUMMARY OF THE INVENTION
The present invention addresses the above needs and achieves other advantages by providing a brassiere for extending around a wearer's torso and supporting the wearer's breasts. The brassiere includes a torso strap supporting a pair of breast cups which in turn support the wearer's breasts. The breast cups are constructed of a two-ply fabric, preferably a circularly knit fabric, and each of the breast cups has a fold line positioned along at least a portion of its upper edge so as to improve wearer comfort and eliminate the need for elastic trim along the upper edge and thereby reduce seams visible through clothing. Optionally, the fold may be knit to have a thinner material than the remaining plies to facilitate formation of a crisp fold along the upper edge of the breast cup, which helps the fold lie flat against the wearer's skin and thereby imparts a smooth, finished appearance. Also, an underwire may be attached along a lower edge of each of the breast cups to provide extra support.
In one embodiment, the brassiere of the present invention includes a torso strap and a pair of breast cups. The torso strap has at least one pair of ends. A two-ply fabric material having an inner, body-adjacent layer and an outer layer defines the pair of breast cups. The breast cups are attached adjacently to each other and extend between the ends of the torso strap. Each of the breast cups has a lower edge that when worn extends under a respective one of the wearer's breasts. The lower edge includes a seam extending at least partly therealong. An upper edge of each of the breast cups is configured to extend over at least an upper portion of the respective one of the wearer's breasts. The upper edge is defined by a fold line between the inner and outer layers so as to provide a comfortable fit for the wearer.
In another aspect, the upper edge is configured to extend along a medial portion of the wearer's breast. More particularly, the breast cups are attached at a point between the wearer's breasts and each folded upper edge extends laterally upwards from the attachment point along the medial portions of the wearer's breasts.
The torso strap may also be constructed of a two-ply material and includes at least one edge defined by a fold line between its plies. Preferably, the fold line defines a lower edge of the torso strap. The torso strap may be separated into a pair of lateral panels each having a free end opposite the torso strap's attachment to one of the breast cups. Cooperative fastener members attached to the free ends of the two panels allow the free ends to be releaseably joined so that the torso strap can be secured about the wearer's body.
The two-ply fabric material defining the breast cups may be formed of a circularly knit fabric blank folded upon itself along the fold line defining the upper edge of each of the breast cups. The free edges of the breast cups may have underwires either disposed against an exterior side of one of the plies, or between the plies to provide extra support for the wearer's breasts.
In yet another embodiment, the present invention includes a blank for making a brassiere. The blank includes a first series of courses defining a first pair of breast cup panels and a first torso strap panel. The first series of courses begins at a first end of the fabric structure and progresses toward an opposite, second end of the fabric structure. An end of the first series of courses defines an upper edge of the breast cup panels and a lower edge of the torso strap panel. A second series of courses is knit to the end of the first series of courses, progressing to the second end of the fabric structure. The second series of courses defines a second pair of breast cup panels and a second torso strap panel arranged in mirror image to the corresponding panels of the first series of courses. In this manner, the fabric structure can be folded about a fold line located between the first and second series of courses to create a two-ply structure having the first breast cup panels and the first torso strap panel overlying the second breast cup panels and the second torso strap panel, respectively.
Preferably, the fabric structure is a circularly knit fabric tube, which may have a turned welt at one or each end of the tube. Also, the fold line may have a thinner knit than the rest of the blank so as to facilitate sharp folding so that these edges of a finished brassiere that are formed by the fold will lie flat against the wearer's skin.
The present invention has many advantages. For instance, the smooth upper medial edge on each of the breast cups and the smooth bottom edge of the torso strap minimizes the amount of stitching and or banding needed to form the brassiere. Banding and seams tend to show through clothing, creating unsightly lines, especially when in contact with the clothing, such as on the top edge of a breast cup immediately beneath a blouse or shirt. Avoiding the use of seams and/or banding on the upper edge of the breast cup where a blouse or top generally makes close contact therefore improves the aesthetic appearance of the wearer. In addition, reduction of banding and stitching tends to reduce the effort and cost of constructing the brassiere.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)
Having thus described the invention in general terms, reference will now be made to the accompanying drawings, which are not necessarily drawn to scale, and wherein:
FIG. 1 is a perspective view of a two-ply brassiere of one embodiment of the present invention being worn by a wearer;
FIG. 2 is a plan view of the brassiere of FIG. 1 laid flat;
FIGS. 3-5 are sectional views of the brassiere of FIG. 1 along the section lines shown in FIG. 2;
FIG. 6 is a perspective view of a tubular blank defining panels of the brassiere of another embodiment of the present invention; and
FIG. 7 is a plan view of the tubular blank of FIG. 6 cut longitudinally and laid flat.
DETAILED DESCRIPTION OF THE INVENTION
The present inventions now will be described more fully hereinafter with reference to the accompanying drawings, in which some, but not all embodiments of the invention are shown. Indeed, these inventions may be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided so that this disclosure will satisfy applicable legal requirements. Like numbers refer to like elements throughout.
A brassiere 10 of one embodiment of the present invention is shown in FIGS. 1 and 2. The brassiere includes a pair of breast cups 14 , a torso strap 16 attached to the breast cups and a pair of shoulder straps 20 attached to the breast cups and the torso strap. The brassiere 10 also includes an underwire 24 sewn to each breast cup for further stability, as shown in FIGS. 2, 3 and 5 . Each underwire 24 is encased in a fabric casing 26 and the casing is sewn or otherwise attached to the respective breast cup.
The breast cups 14 and torso strap 16 preferably have a knit structure that makes them resiliently stretchable vertically and horizontally. The breast cups 14 and torso strap 16 can be knit, for example, from various types of face yarns depending on the desired properties of the fabric, and the face yarns can be of various deniers. The selection of the face yarns and the knit depend primarily on the desired characteristics of the fabric such as the hand, appearance, texture, etc. The breast cups 14 and torso strap 16 can also incorporate elastomeric yarns such as spandex (bare and/or covered) or the like so as to impart resiliency to the fabric.
If desired, portions of the breast cups 14 and torso strap 16 may be knit to achieve greater resistance to stretching, as described in commonly assigned U.S. Pat. No. 6,287,168 which is incorporated herein by reference. For instance, some parts of the breast cups 14 and torso strap 16 may be knit from different yarns or can have a different configuration of stitch loops than the other parts.
The torso strap 16 in the illustrated embodiment is formed in two halves comprising one lateral panel having one end attached to one of the breast cups 14 and another lateral panel having one end attached to the other breast cup. The free end of one of the halves of the torso strap has fastener members 28 , such as hooks, attached to it. The free end of the other half of the torso strap has cooperative fastener members 30 , such as eyes, attached to it for engagement with the opposite fastener members 28 so that the brassiere can be engaged about the torso of a wearer.
The brassiere 10 preferably has a two-ply construction as best seen in the cross-sectional views of FIGS. 3 through 5. Each of the breast cups 14 and the torso strap 16 are formed from a piece of fabric, preferably cut from a single, continuous piece of circular-knit fabric, folded upon itself to define an inner ply 32 that faces the wearer's body and an outer ply 34 that faces outward. Advantageously, the plies of the breast cups are folded so as to strategically place their edges formed by folding for maximum comfort and to minimize the appearance of seams through outer clothing. For instance, as can be seen in the illustrated embodiment, a fold line of the plies of each of the breast cups 14 is positioned so as to form a bandless upper, medial edge 38 . A fold line of the torso encircling strap 16 is on the bottom of the torso encircling strap so as to form a bandless bottom edge 50 . The orientation and size of the smooth upper edge of the breast cups 14 can be changed to suit the style or type of the brassiere and still be within the scope of the present invention. For instance, a lateral portion of the upper edge may be smooth and seamless.
The lower, free ends of the plies of each of the breast cups 14 are folded over (forming a four-ply region for a smooth edge) and stitched together with the same stitching used to secure the fabric casing 26 enclosing the underwire 24 to the breast cups, as shown by the sectional view in FIG. 3 . In non-underwire brassieres, the free edges of the breast cups can be secured by stitching, ultrasonically welding, gluing, or otherwise attaching a strip of elastic or non-elastic banding that is wrapped over the free edges of the breast cups for a finished edge. Also, the underwire can be attached in other configurations, such as by being sealed or stitched between the plies of the breast cups 14 , or housed in the fabric casing 26 stitched onto the front of the breast cups.
Medial portions of the free ends of the plies forming the torso encircling strap 16 adjacent the breast cups 14 are also secured to the breast cups by stitching or otherwise attaching the fabric casing 26 and underwire 24 to the breast cups. In particular, the medial portions of the free ends of the torso strap 16 plies are secured between the plies of the breast cups 14 and the casing 26 , as shown by the sectional view in FIG. 5 . The remainder of the free ends of the plies along the upper edge of the torso strap 16 and the lateral edges of the breast cups 14 are secured together by extending the portions of the shoulder straps 20 thereover. The shoulder straps are preferably formed of a strip of banding 36 folded over on itself and joined together. The banding is also wrapped about the free edges of the plies of the breast cups 14 and torso strap 16 and secured thereto, as shown by the sectional view of FIG. 4 .
The brassiere 10 preferably is fabricated from a circularly knit fabric tube 40 , as shown in FIG. 6 . The tube 40 preferably has a turned welt 42 formed at one end and may have another turned welt (not shown) at the other end to prevent the tube from raveling and to facilitate handling of the fabric in subsequent fabrication processes as described below. Knitting of the tube 40 begins by knitting the turned welt 42 . A first series of courses is then knit to the turned welt 42 so as to form a first tubular structure 40 a defining panels 14 for forming the breast cups and the torso strap 16 . The first series of courses terminates at a fold region 46 that will define the lowermost edge of the finished brassiere.
Preferably, the fold region 46 is knit to be thinner than the rest of the fabric tube, which can be accomplished, for example, by dropping the heavier yarns for a few courses (e.g., for about 8 courses) such that only the lighter yarns are knit for those courses. Next, a second series of courses is knit to the end of the first series of courses so as to form a second tubular structure 40 b forming an extension of the first tubular structure 40 a . The second tubular structure 40 b defines breast cup panels 14 and torso strap panel 16 in mirror image to the corresponding features of the first tubular structure about the fold region 46 . At the end of the second series of courses, an optional turned welt can be knit and the fabric tube 40 is taken off the circular knitting machine.
By folding the fabric tube 40 about the fold region 46 , the second tubular structure 40 b can be positioned in overlying relation to the first tubular structure 40 a so that the breast cup panels and torso strap panels of the two tubular structures are overlying and in registration with each other. If it is desired to fabricate a brassiere having a single continuous torso strap 16 (i.e., such that the wearer dons the brassiere by slipping it over the head and onto the torso), the folded fabric tube 40 can then be cut along sew lines defining the outlines of the breast cup panels 14 and the torso strap panels. In particular, a pair of the overlapping breast cup panels 14 are separated from the other pair of the overlapping breast cup panels and the overlapping torso panels 16 prior to folding and stitching.
The panels are then stitched together into the above-described finished arrangement by rotating the breast cup panels 14 until the fold lines 38 are oriented as the upward medial edges of the breast cups, as shown in FIGS. 1 and 2. The medial portions of the free edges of the plies forming the torso encircling strap 16 are secured to the adjacent portions of free edges of the breast cups 14 by attachment of the underwire 24 and its fabric casing 26 , as shown in FIGS. 3 and 5. Attachment of the fabric casing also attaches the breast cups 14 together. The shoulder straps 20 are attached to the remaining free edges of the breast cup panels 14 and the torso panels 16 . It should be noted that these steps may be performed in different orders, such as cutting and then folding each of the panels.
Alternatively, the fabric tube 40 can be slit along a longitudinal line 48 located generally diametrically opposite from the breast cup panels 14 , as shown in FIG. 6, and the slit tube can be opened up into a flat configuration as depicted in FIG. 7 . The resulting flat blank can then folded about the fold region 46 , and then the steps of cutting and attaching the underwires and the shoulder straps 30 can be peformed. In this case, the torso strap 26 is formed in two halves and fastener members 28 , 30 are attached to the ends of the two halves as with the brassiere 10 of FIG. 2 . This fabrication method enables the girth of the torso strap to be reduced from the full girth of the fabric tube 40 , if desired.
The flat fabric blank of FIG. 7 can be boarded, if desired, to make it lay flat and to take out wrinkles. The turned welt 42 or welts can facilitate handling the blank during the boarding and other processes, and also prevent the edges of the blank from curling and raveling.
Preferably, the breast cups 14 are molded after the fabric tube 40 is slit and breast cup panels are folded about the fold region 46 , so that the breast cups are shaped with a desired contour. To this end, the fabric at least in the breast cup regions includes a heat-settable yarn. Molding can be performed on a conventional molding device, which generally includes a heated convex form and a frame that stretches the fabric over the form so that the heat-settable yarn is softened while in the stretched condition. After softening, the fabric is removed from the form and the heat-settable yarn cools so as to permanently retain the contoured shape of the breast cup. If desired, one two-ply breast cup may be placed over the other two-ply breast cup prior to molding so that both cups are molded simultaneously.
It is also possible to fabricate a blank for the brassiere by circularly knitting a two-ply fabric tube. The tube is essentially knit as one long turned welt by knitting a first series of courses that will become an outer ply of the blank and by knitting a second series of courses that will become the inner ply of the blank. For example, the tube can be knit on a circular knitting machine having cylinder needles and dial needles, the cylinder needles being used to knit the first series of courses and the dial needles being used to knit the second series of courses. The knitting of two-ply tubes is a process known to those of skill in the art, and hence is not further described herein. By knitting the tube as a two-ply structure, the tube does not require turned welts at the ends such as included with the previously described one-ply tube, and the blank comes off the knitting machine as a two-ply structure so as to eliminate the need to fold the blank before cutting.
The present invention has many advantages. For instance, the smooth upper medial edge 38 on each of the breast cups 14 and the smooth bottom edge 50 of the torso strap 16 minimize the amount of stitching and or banding needed to form the brassiere 10 . Banding and seams tend to show through clothing, creating unsightly lines, especially when in contact with the clothing, such as on the top edge of a breast cup immediately beneath a blouse or shirt. Avoiding the use of seams and/or banding on the upper edge of the breast cup where a blouse or top generally makes close contact therefore improves the aesthetic appearance of the wearer. In addition, elimination of banding and stitching tends to reduce the effort and cost of constructing the brassiere 10 .
Many modifications and other embodiments of the inventions set forth herein will come to mind to one skilled in the art to which these inventions pertain having the benefit of the teachings presented in the foregoing descriptions and the associated drawings. Therefore, it is to be understood that the inventions are not to be limited to the specific embodiments disclosed and that modifications and other embodiments are intended to be included within the scope of the appended claims. Although specific terms are employed herein, they are used in a generic and descriptive sense only and not for purposes of limitation. | A brassiere for extending around a wearer's torso and supporting the wearer's breasts. The brassiere includes a torso strap supporting a pair of breast cups which in turn support the wearer's breasts. The breast cups are constructed of a two-ply fabric, preferably a circularly knit fabric, and each of the breast cups has a fold line positioned along at least a portion of its top edge so as to improve wearer comfort and reduce seams visible through clothing. Also, an underwire may be attached to an exterior side of one of the plies of the two-ply material of each of the breast cups to provide extra support. Optionally, the fold may be knit to have a thinner material than the remaining plies to facilitate formation of a smooth folded upper edge of the breast cup with a finished appearance. | 3 |
This application is a Divisional of application Ser. No. 10/028,759, filed on Dec. 28, 2001, now U.S. Pat. No. 6,833,883, and for which priority is claimed under 35 U.S.C. § 120; and this application claims priority of Application No. 2001-7097 and 2001-30699 filed in Korea on Feb. 13, 2001 and Jun. 1, 2001, under 35 U.S.C. § 119; the entire contents of all are hereby incorporated by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to liquid crystal display devices, and more particularly, to an array substrate for reflective and transflective liquid crystal display devices.
2. Description of the Background Art
Generally, a reflective liquid crystal display device does not need to equip an additional light source such as a back light because it can substitute an external light source for the back light. A transflective liquid crystal display device has both properties of the reflective liquid crystal display device and a transmissive liquid crystal display device. Because the transflective liquid crystal display device utilizes both of the back light and the external light source, it can save power consumption.
FIG. 1 illustrates a liquid crystal panel for a conventional transflective liquid crystal display device. The conventional transflective liquid crystal display device 11 has an upper substrate 15 that includes a color filter 18 a transparent common electrode 13 and a lower substrate 21 that includes a pixel region “P”, a pixel electrode 19 , thin film transistor and an array of gate lines 25 and data lines 27 . The color filter 18 includes a black matrix 16 and sub-color filters R, G and B. The pixel electrode 19 has a transmission portion “A” and a reflection portion “PR”. Liquid crystal 23 is interposed between the upper substrate 15 and the lower substrate 21 . The lower substrate 21 is also referred to as an array substrate with thin film transistors “T”, switching elements, arranged in a matrix on the array substrate 21 . A plurality of horizontal gate lines 25 and a plurality of vertical data lines 27 cross each other defining the pixel region “P”. If the transparent pixel electrode 19 and the transmission portion “A” are omitted from the transflective liquid crystal display device, it becomes a reflective liquid crystal display device.
FIG. 2 is a plan view illustrating a partial array substrate for a conventional reflective liquid crystal display device. As shown in the figure, a plurality of gate lines 25 and a plurality of data lines 27 cross each other defining a pixel region “P”. A thin film transistor “T” is formed at a crossing portion of the gate line 25 and the data line 27 . The thin film transistor “T” usually includes a gate electrode 32 , a source electrode 33 , a drain electrode 35 and an active layer 34 . A pixel electrode 19 is formed in the pixel region “P” and the thin film transistor “T” connected to the drain electrode 35 drives the liquid crystal 23 of FIG. 1 . A reflective electrode, which is formed of opaque conductive metal having a high reflexibility, is substituted for the pixel electrode 19 in the reflective liquid crystal display device. The opaque conductive metal is selected from a group consisting of aluminum (Al) and aluminum alloys (AlNd, for example), for example.
Because the reflective liquid crystal display device uses an external light source, incident light from the external light source passes through the upper substrate (not shown) and is then reflected at the reflective electrode 10 on the array substrate 21 . The reflected light subsequently passes through the liquid crystal and thereby polarization properties of the light are changed according to birefringence properties of the liquid crystal. Color images can be displayed when the light passing through the liquid crystal colors the color filter.
FIG. 3 is a cross-sectional view taken along III-III of FIG. 2 according to the conventional art. As shown in the figure, a gate electrode 32 and a gate line 25 of FIG. 2 are formed on a substrate 21 . A gate insulating layer 41 is formed on the substrate 21 and on the gate electrode 32 . An active layer 34 is formed on the gate insulating layer 41 and partially overlapped with a source electrode 33 and a drain electrode 35 . The source electrode 33 , the drain electrode 35 and the data line 27 are formed on the active layer 34 . A thin film transistor includes the gate electrode 32 , the source electrode 33 , the drain electrode 35 and the active layer 34 . A passivation layer 43 made of insulating material is formed on the thin film transistor. The passivation layer 43 is subsequently patterned to form a drain contact hole 45 exposing a part of the drain electrode 35 . A reflective electrode 19 contacts the drain electrode 35 through the drain contact hole 45 . The material for the reflective electrode 19 is selected from a group including aluminum (Al) and aluminum alloy (AlNd, for example), etc.
FIG. 5 is a cross-sectional view taken along line V-V of FIG. 4 according to the conventional art. A thin film transistor “T” including a gate electrode 32 , a source electrode 33 , a drain electrode 35 and an active layer 34 is formed and a first passivation layer 43 is formed on the thin film transistor “T”. The first passivation layer 43 is formed by depositing a transparent organic insulating material such as benzocyclobutene (BCB) and acrylic resin. A drain contact hole 45 that exposes a part of the drain electrode 35 is formed and a etching hole 53 is formed by etching the first passivation layer 43 corresponding to the transmission hole 53 in the pixel region “P”. A reflective electrode 19 a that contacts the drain electrode 35 through the drain contact hole 45 is formed in the pixel region “P”. The reflective electrode 19 a is formed of aluminum (Al) and aluminum alloys (AlNd, for example), etc. A second passivation layer 47 is formed on the reflective electrode 19 a and patterned to expose the reflective electrode 19 a corresponding to the drain contact hole 45 . The second passivation layer 47 is formed of insulating material such as silicon oxide (SiO 2 ) or silicon nitride (SiN X ), for example. A transparent pixel electrode 19 b that contacts the exposed reflective electrode 19 a through the patterned second passivation layer 47 is formed on the second passivation layer 47 .
Several masks for patterning array elements of the array substrate are used in the manufacturing of the conventional reflective and transflective liquid crystal display device. An align key for accurate aligning of the mask and the substrate is formed on the corner of the substrate simultaneously with the gate line or the data line forming process. The shape of the align key has unevenness. Accordingly, a detector aligns the mask and the substrate by irradiating light onto the uneven surface of the align key and sensing the light reflected from the surface of the align key.
FIG. 6 is a plan view illustrating a partial array substrate having a coplanar type polysilicon thin film transistor for a conventional transflective liquid crystal display device. A gate line 71 and a data line 84 cross each other defining a pixel region “P” and a thin film transistor “T” is formed at a crossing portion of the gate line 71 and the data line 84 . The thin film transistor “T” is a polysilicon thin film transistor that includes a polysilicon active layer and has a coplanar structure in which a gate electrode 70 is formed under a source electrode 80 and a drain electrode 82 . A gate pad 74 and a data pad 86 , which receive an external signal, are formed respectively at one end of the gate line 71 and the data line 84 . The gate pad 74 and the data pad 86 respectively contact a gate pad terminal 94 and a data pad terminal 96 that are formed of transparent conductive material. The thin film transistor “T” includes the gate electrode 70 , the source electrode 80 , the drain electrode 82 and an active layer 66 . The active layer 66 has an active layer expanded portion 67 in the pixel region “P”. A storage line 72 is formed parallel to the gate line 71 with a same material as that of the gate line 71 and has a storage line expanded potion 73 in the pixel region “P”. The pixel electrode 63 contacts the drain electrode 82 . A storage capacitor portion “C” and a reflection portion “PR” are formed in the pixel region “P”. A reflector 102 is formed on the storage capacitor portion “C”. The rest potion of the pixel region “P” except the reflector 102 is a transmission portion “F”.
FIGS. 7A to 7F are cross-sectional views taken along IV-IV, V-V, VI-VI of FIG. 6 illustrating a fabricating sequence of an array substrate according to the related art. In FIG. 7A , a first insulating layer 62 is formed on a substrate 60 by depositing inorganic insulating material such as silicon oxide (SiO 2 ) or silicon nitride (SiN X ) and an amorphous silicon layer 64 is formed on the first insulating layer by depositing amorphous silicon (a-Si:H). The first insulating layer 62 , referred to as a buffer layer, is for preventing an expansion of alkaline substances from the substrate 60 . The amorphous silicon layer 64 is crystallized into polysilicon by introducing a solid phase crystallization (SPC) method, a metal induced crystallization (MIC) method, a laser annealing method and a field effect metal induced crystallization (FEMIC) method.
In FIG. 7B , a semi-conductor layer 66 is formed by patterning the crystallized layer and a gate insulating layer 68 , a second insulating layer, is formed on the semi-conductor layer 66 . A conductive metal layer is subsequently formed on the gate insulating layer 68 . A gate electrode 70 and a gate line 71 of FIG. 6 are formed by patterning the deposited conductive metal layer. The semi-conductor layer 66 has a semi-conductor layer expanded portion 67 in the pixel region “P”. The gate pad 74 is formed at one end of the gate line 71 . The storage line 72 is simultaneously formed parallel to the gate line 71 and the storage line 72 has the storage line expanded portion 73 on the pixel region “P”.
The semi-conductor layer 66 can be divided into two regions, one is a first active region “A” and the other is a second active region “B”. The first active region “A” is a pure silicon region and the second active region “B” is an impure silicon region. The second active regions “B” are positioned at both sides of the first active region “A”. The gate insulating layer 68 and the gate electrode 70 are formed on the first active region “A”. After forming of the gate electrode 70 , ion doping is performed onto the second active region “B” to form a resistant contact layer. The gate electrode 70 serves as an ion stopper that prevents dopants from penetrating into the first active region “A”. After the ion doping is finished, the semi-conductor layer 66 , the polysilicon island, implements a specific electric characteristic, which varies with types of the dopants. If the dopant is, for example, B 2 H 6 that includes a Group III element, a doped portion of the polysilicon island 66 becomes a p-type semiconductor. Whereas, if the dopant is PH 3 that includes a Group VI element, the doped portion of the polysilicon island 66 becomes an n-type semiconductor. A proper dopant should be selected to satisfy the use of a device. After the dopant is applied onto the polysilicon island 66 , the dopant is activated.
In FIG. 7C , a third insulating layer 76 , i.e, an interlayer insulator, is formed over the whole area of the substrate 60 and is patterned to form a source contact hole 78 a and a drain contact hole 78 b . A source electrode 80 and a drain electrode 82 , which contact the second active region “B” through the source contact hole 78 a and the drain contact hole 78 b , respectively, are formed by depositing and then patterning conductive metals such as aluminum (Al), aluminum alloys, tungsten (W), copper (Cu), chromium (Cr) and molybdenum (Mo), etc. A data line 84 that contacts the source electrode 80 is simultaneously formed and a data pad 86 is formed at one end of the data line 84 . The polysilicon thin film transistor “T” is formed through the above processes.
In FIG. 7D , a fourth insulating layer 88 is formed on the whole area of the substrate 60 and then the thin film transistor undergoes a hydrogenation process. The hydrogenation process is for removing defects that occurred on the surface of the active layer 66 . A fifth insulating layer 90 is formed on the fourth insulating layer 88 using transparent organic insulating material such as benzocyclobutene (BCB) or acrylic resin. A first drain contact hole 92 exposing the drain electrode 82 , a gate pad contact hole 91 exposing the gate pad 74 and a data pad contact hole 95 exposing the data pad 86 are formed by patterning simultaneously the laminated layers.
In FIG. 7E , a pixel electrode 93 that contacts the exposed drain electrode 82 and is extended to the pixel region, a gate pad terminal 94 that contacts the exposed gate pad and a data pad terminal 96 that contacts the exposed data pad are formed on the fifth insulating layer 90 using transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO), for example.
In FIG. 7F , a sixth insulating layer 98 is formed on the whole area of the substrate 60 using silicon oxide (SiO 2 ) or silicon nitride (SiN X ), for example. A second drain contact hole 100 that exposes the pixel electrode 93 contacting the drain electrode 82 is formed by patterning the sixth insulating layer 98 . A reflective electrode 102 , which contacts the exposed pixel electrode 93 , is formed on the sixth insulating layer 98 using conductive metal such as aluminum (Al) or aluminum alloys, for example. A first etching hole 104 that exposes the gate pad terminal 94 and a second etching hole 106 that exposes the data pad terminal 96 are formed by patterning the sixth insulating layer 98 . The reason for exposing the gate pad terminal 94 and the data pad terminal 96 in the last process is to prevent the pixel electrode 93 and the reflective electrode 102 from being etched together in etching solution during an etching process for the reflective electrode 102 .
Conventional reflective or transflective liquid crystal display devices have some problems described as follows. First, because a reflective electrode is formed on an organic insulating layer such as benzocyclobutene (BCB) and the contact property of the reflective electrode and the benzocyclobutene (BCB) layer is not good, the reflective electrode may not be stably deposited on the organic insulating layer. This lacks of stability lowers electric properties of a liquid crystal panel. Second, when a sputtering process is used for forming the reflective electrode on the benzocyclobutene (BCB), accelerated electrons collide into the surface of the benzocyclobutene (BCB) and separate the benzocyclobutene (BCB) particles from the surface, which produces benzocyclobutene (BCB) particles in a deposition chamber. The benzocyclobutene (BCB) particles in the deposition chamber contaminate the deposition chamber. Lastly, an align key may not be detected by a detecting apparatus if the benzocyclobutene (BCB) is deposited on the substrate and covers the align key. Accordingly, alignment error of a mask and the substrate may be occurred during a light exposing process for patterning the reflective electrode.
SUMMARY OF THE INVENTION
Accordingly, the present invention is directed to an array substrate for reflective and transflective liquid crystal display devices and a manufacturing method of the array substrate for reflective and transflective liquid crystal display devices that substantially obviates one or more of problems due to limitations and disadvantages of the related art.
An object of the present invention is to provide an array substrate for a reflective liquid crystal display device, wherein a reflective electrode is not formed on organic insulating material such as benzocyclobutene (BCB), but formed on inorganic insulating material such as silicon nitride (SiN X ) to improve contact property of the reflective electrode and to prevent a deposition chamber from being contaminated with particles of the organic insulating material.
Another object of the present invention is to provide a manufacturing method of an array substrate for a reflective liquid crystal display device.
Another object of the present invention is to provide an array substrate for a transflective liquid crystal display device, wherein a reflective electrode is not formed on organic insulating material such as benzocyclobutene (BCB), but formed on inorganic insulating material such as silicon nitride (SiN X ) to improve contact property of the reflective electrode and to prevent a deposition chamber from being contaminated with particles of the organic insulating material.
Another object of the present invention is to provide a manufacturing method of an array substrate for a transflective liquid crystal display device.
Another object of the present invention is to provide an array substrate for a transflective liquid crystal display device having a barrier layer between an organic insulating layer and a reflector to improve contact property of the reflective electrode and to prevent a deposition chamber from being contaminated with particles of the organic insulating material.
Another object of the present invention is to provide a manufacturing method of an array substrate for a transflective liquid crystal display device having a barrier layer between an organic insulating layer and a reflector.
To achieve these and other advantages, one embodiment of the present invention, an array substrate for a reflective liquid crystal display device includes a gate line and a data line defining a pixel region by crossing each other, a switching element at a crossing portion of the gate line and the data line, a first passivation layer covering the switching element and the data line, the first passivation layer being formed of inorganic insulating material, a reflective electrode on the first passivation layer, the reflective electrode being connected to the switching element, and a second passivation layer on the reflective electrode, the second passivation layer being formed of organic insulating material. The reflective electrode is formed of conductive metal material such as aluminum (Al) or aluminum alloys, for example. The switching element is a thin film transistor including a gate electrode, a source electrode, a drain electrode and an active layer. The first passivation layer is desirably formed of silicon nitride (SiN X ). The second passivation layer is formed of organic insulating material such as benzocyclobutene (BCB) or acrylic resin, for example.
In another aspect, a preferred embodiment of a manufacturing method of an array substrate for a reflective liquid crystal display device includes the steps of forming a gate line and a data line that define a pixel region by crossing each other; forming a switching element at a crossing portion of the gate line and the data line; forming a first passivation layer covering the switching element and the data line; the first passivation layer being formed of inorganic insulating material; forming a reflective electrode on the first passivation layer, the reflective electrode being connected to the switching element; and, forming a second passivation layer on the reflective electrode. The second passivation layer being formed of organic insulating material.
The reflective electrode may be formed of conductive metal material such as aluminum (Al) or aluminum alloys, for example. The switching element is a thin film transistor including a gate electrode, a source electrode, a drain electrode and an active layer. The first passivation layer is preferably formed of silicon nitride (SiN X ). The second passivation layer is formed of organic insulating material such as benzocyclobutene (BCB) or acrylic resin, for example.
In another embodiment, an array substrate for a transflective liquid crystal display device includes a gate line and a data line defining a pixel region by crossing each other; a switching element at a crossing portion of the gate line and the data line; a first passivation layer covering the switching element and the data line and being formed of inorganic insulating material; a reflective electrode on the first passivation layer, connected to the switching element and including a transmission hole; a second passivation layer on the reflective electrode, formed of organic insulating material and patterned to expose a part of the switching element; and a transparent pixel electrode on the second passivation layer, formed in the pixel region and contacting the exposed part of the switching element.
The reflective electrode is formed of conductive metal material such as aluminum (Al) or aluminum alloys, for example. The switching element is a thin film transistor including a gate electrode, a source electrode, a drain electrode and an active layer. The first passivation layer is desirably formed of silicon nitride (SiN X ). The second passivation layer is formed of organic insulating material such as benzocyclobutene (BCB) or acrylic resin, for example.
In another embodiment, a manufacturing method of an array substrate for a transflective liquid crystal display device includes the steps of forming a gate line and a data line defining a pixel region by crossing each other; forming a switching element at a crossing portion of the gate line and the data line; forming a first passivation layer covering the switching element and the data line, the first passivation layer being formed of inorganic insulating material; forming a reflective electrode on the first passivation layer, the reflective electrode being connected to the switching element and including a transmission hole; forming a second passivation layer on the reflective electrode, the second passivation layer being formed of organic insulating material and patterned to expose a part of the switching element; and forming a transparent pixel electrode on the second passivation layer. The pixel electrode being formed in the pixel region and contacting the exposed part of the switching element. The reflective electrode is formed of conductive metal material such as aluminum (Al) or aluminum alloys, for example. The switching element is a thin film transistor including a gate electrode, a source electrode, a drain electrode and an active layer. The first passivation layer is desirably formed of silicon nitride (SiN X ). The second passivation layer is formed of organic insulating material such as benzocyclobutene (BCB) or acrylic resin, for example.
In another embodiment, an array substrate for a transflective liquid crystal display device includes a thin film transistor including an active layer a gate electrode and source and drain electrodes, being formed on a substrate in sequence; a gate line including a gate pad at one end of it, the gate line being connected to the gate electrode; a storage line being formed parallel to the gate line and being spaced apart from the gate line; a data line defining a pixel region by crossing the gate line, including a data pad at one end of it and being connected to the source electrode; an organic insulating layer over the thin film transistor and the data line; a barrier layer on the organic insulating layer and formed of inorganic insulating material; a reflector on the barrier layer, and a transparent pixel electrode on an inorganic insulating layer. The pixel electrode contacting the drain electrode, and the inorganic insulating layer being formed between the reflector and the pixel electrode. The array substrate for a transflective liquid crystal display device may further include a buffer layer beneath the active layer using inorganic insulating material such as silicon oxide (SiO 2 ) or silicon nitride (SiN X ), for example. The active layer is formed of polysilicon. The storage line is desirably formed with a same material as that of the gate line on a same layer as that of the gate line. The reflector is formed of conductive metal material such as aluminum (Al) or aluminum alloys, for example. The pixel electrode is formed of transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO), for example. The reflector may desirably be extended to the data line and simultaneously cover the thin film transistor. The reflector may be partially overlapped with the gate line and the gate line. The barrier layer is formed using inorganic insulating material such as silicon oxide (SiO 2 ) or silicon nitride (SiN X ), for example. The array substrate further may include an insulating layer beneath the organic insulating layer to perform a hydrogenation process of the thin film transistor. The barrier layer is desirably formed of silicon nitride (SiN X ).
In another embodiment, a manufacturing method of an array substrate for a transflective liquid crystal display device includes the steps of forming a thin film transistor including an active layer, a first insulating layer, a gate electrode, a second insulating layer being formed on a substrate in sequence; forming a gate line and a storage line such that, the gate line includes a gate pad at one end of it and being connected to the gate electrode; and the storage line is formed parallel to the gate line and spaced apart from the gate line; forming a data line defining a pixel region by crossing the gate line including a data pad at one end of it and being connected to the source electrode, forming a third insulating layer over the thin film transistor and the data line, the third insulating layer being formed of transparent organic insulating material; forming a fourth insulating layer on the third insulating layer, the third insulating layer being a barrier layer and being formed of inorganic insulating material; forming a reflector on the barrier layer; forming a drain contact hole over the drain electrode by depositing and patterning a fifth insulating layer on the reflector; and forming a transparent pixel electrode on an inorganic insulating layer, the pixel electrode contacting the drain electrode. The inorganic insulating layer being formed between the reflector and the pixel electrode. The array substrate for a transflective liquid crystal display device may further include a buffer layer beneath the active layer using inorganic insulating material such as silicon oxide (SiO 2 ) or silicon nitride (SiN X ), for example. The active layer is formed of polysilicon. The storage line is desirably formed with a same material as that of the gate line on a same layer as that of the gate line. The reflector is formed of conductive metal material such as aluminum (Al) or aluminum alloys, for example. The pixel electrode is formed of transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO). The reflector may desirably be extended to the data line and cover the thin film transistor. The reflector may be partially overlapped with the gate line and the gate line. The barrier layer is formed using inorganic insulating material such as silicon oxide (SiO 2 ) or silicon nitride (SiN X ), for example. The manufacturing method of the array substrate according to the present invention further includes forming an insulating layer beneath the organic insulating layer to perform a hydrogenation process of the thin film transistor. The barrier layer is desirably formed of silicon nitride (SiN X ).
These and other objects of the present application will become more readily apparent from the detailed description given hereinafter. However, it should be understood that the detailed description and specific examples, while indicating preferred embodiments of the invention, are given by way of illustration only, since various changes and modifications within the spirit and scope of the invention will become apparent to those skilled in the art from this detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will become more fully understood from the detailed description given hereinbelow and the accompanying drawings which are given by way of illustration only, and thus are not limitative of the present invention and wherein:
FIG. 1 is an exploded perspective view illustrating a liquid crystal panel for a conventional transflective liquid crystal display device;
FIG. 2 is a plan view illustrating a partial array substrate for a conventional reflective liquid crystal display device;
FIG. 3 is a cross-sectional view taken along line III-III of FIG. 2 according to the conventional art;
FIG. 4 is a plan view illustrating a partial array substrate having an inverted stagger type thin film transistor for a conventional transflective liquid crystal display device;
FIG. 5 is a cross-sectional view taken along line V-V of FIG. 4 according to the conventional art;
FIG. 6 is a plan view illustrating a partial array substrate having a coplanar type polysilicon thin film transistor for a conventional transflective liquid crystal display device;
FIGS. 7A to 7F are cross-sectional views taken along lines IV-IV, V-V, VI-VI of FIG. 6 illustrating a fabricating sequence of an array substrate according to the conventional art;
FIG. 8 is a plan view illustrating a partial array substrate for a reflective liquid crystal display device according to a first embodiment of the present invention;
FIGS. 9A to 9C are cross-sectional views taken along III-III of FIG. 8 illustrating a method of manufacturing an array substrate according to the first embodiment of the present invention;
FIG. 10 is a plan view illustrating a partial array substrate having an inverted stagger type thin film transistor for a transflective liquid crystal display device according to a second embodiment of the present invention;
FIGS. 11A to 11E are cross-sectional views taken along line V-V of FIG. 10 illustrating a fabricating sequence of an array substrate according to the second embodiment of the present invention;
FIG. 12 is a plan view illustrating a partial array substrate having a coplanar type polysilicon thin film transistor for a transflective liquid crystal display device according to a third embodiment of the present invention; and
FIGS. 13A to 13F are cross-sectional views taken along lines IV-IV, V-V, VI-VI of FIG. 12 illustrating a fabricating sequence of an array substrate according to the third embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Reference will now be made in detail to the preferred embodiment of the present invention, which is illustrated in the accompanying drawings.
A first embodiment of the present invention will be described hereinafter with reference to FIG. 8 and FIGS. 9A to 9C . FIG. 8 is a plan view illustrating a partial array substrate for a reflective liquid crystal display device according to the first embodiment of the present invention. FIGS. 9A to 9C are cross-sectional views taken along III-III of FIG. 8 illustrating a fabricating sequence of an array substrate according to the first embodiment of the present invention. In FIG. 9A , a gate line 125 and a gate electrode 132 are formed on the substrate 111 by depositing conductive metal such as aluminum (Al), aluminum alloys, molybdenum (Mo), copper (Cu), tungsten (W) and chromium (Cr), for example, and patterning it. If the gate electrode 132 and the gate line 125 are formed of aluminum (Al), an additional conductive metal layer for protecting the gate electrode 132 and the gate line 125 may be formed. A gate insulating layer 141 is formed on the substrate 111 and on the gate electrode 132 by depositing or coating organic insulating material or inorganic insulating material. The organic insulating material for the gate insulating layer 141 is selected from a group including benzocyclobutene (BCB) and acrylic resin. The inorganic insulating material for the gate insulating layer 141 is selected from a group including silicon oxide (SiO 2 ) and silicon nitride (SiN X ). A semi-conductor layer 134 is formed on the gate insulating layer 141 by depositing an amorphous silicon layer and impure amorphous silicon layer on the gate insulating layer 141 and patterning it. A data line 127 crossing the gate line 125 , a source electrode 133 connected to the data line 127 and a drain electrode 135 being spaced apart from the source electrode 133 are formed by depositing conductive metal material on the whole area of the substrate 111 and patterning it. Though it is not shown in the figure, an align key is formed on the corner of the substrate 111 during the gate line 125 of FIG. 8 forming process or the data line 127 forming process.
In FIG. 9B , a first passivation layer 143 is formed on the substrate by depositing an inorganic insulating material such as silicon oxide (SiO 2 ) or silicon nitride (SiN X ) and then patterning it to form a drain contact hole 145 exposing a part of the drain electrode 135 . The first passivation layer 143 is formed thin. As a result, it can be formed thin on the align key allowing an uneven shape of the align key be remained.
In FIG. 9C , a reflective electrode 147 that contacts the drain electrode 135 through the drain contact hole 145 is formed on the first passivation layer 143 by depositing and patterning a conductive metal material such as aluminum (Al) or aluminum alloys that has a low electric resistance and high reflexibility. At this time, a detection of the align key can be performed well during the depositing and etching process for the reflective electrode 147 . Accordingly, a process error caused by an alignment error of the mask and the substrate does not occur during the reflective electrode forming process. A second passivation layer 149 is formed on the substrate 111 by depositing organic insulating material.
If silicon nitride (SiN X ) is formed beneath the reflective electrode 147 , the electrical conduction property of the liquid crystal panel can be improved and contact property between the reflective electrode 147 and the first passivation layer 143 can be improved, which results in an improvement of electric properties of a liquid crystal panel.
A second embodiment of the present invention will be described hereinafter with reference to FIG. 10 and FIGS. 11A to 11E . FIG. 10 is a plan view illustrating a partial array substrate having an inverted stagger type thin film transistor for a transflective liquid crystal display device according to the second embodiment of the present invention. FIGS. 11A to 11E are cross-sectional views taken along line V-V of FIG. 10 illustrating a fabricating sequence of an array substrate according to the second embodiment of the present invention. In FIG. 11A , because a thin film transistor forming process is the same as that of the first embodiment, i.e., a reflective liquid crystal display device, it will not be described in detail herein.
As shown in FIG. 11A , a gate electrode 132 , a source electrode 133 , a drain electrode 135 , an active layer 134 and a data line 127 are formed on a substrate 111 in sequence. Though it is not shown in the Figures, an align key for accurate aligning of the mask and the substrate is formed on the corner of the substrate simultaneously with the gate line or the data line forming process. The shape of the align key is uneven. Accordingly, a detector aligns the mask and the substrate by irradiating light onto the uneven surface of the align key and sensing the light reflected from the surface of the align key.
In FIG. 11B , a first passivation layer 149 is formed on the substrate 111 and on the thin film transistor “T” by depositing inorganic insulating material such as silicon nitride (SiN X ), for example, on the substrate 111 . Because the first passivation layer 149 is formed thin on the substrate 111 compared with organic insulating material such as benzocyclobutene (BCB), for example, the uneven shape of the align key may remain. A first drain contact hole 150 a for exposing a part of the drain electrode 135 is formed by patterning the first passivation layer 149 .
In FIG. 11C , a reflector 153 that includes a transmission hole 151 in the pixel region is formed by depositing and patterning a metal such as aluminum (Al) and aluminum alloys, for example, on the first passivation layer 149 . At this time, a detection of the align key can be achieved well during the depositing and etching process for the reflector 153 . Accordingly, a process error caused by an alignment error of the mask and the substrate is not occurred during the reflective electrode forming process.
In FIG. 11D , a second passivation layer 154 is formed on the substrate 111 by depositing transparent organic insulating material such as benzocyclobutene (BCB) and acrylic resin. A second drain contact hole 150 b that exposes a part of the drain electrode 135 is formed by etching the second passivation layer 154 corresponding to the first drain contact hole 150 a of FIG. 11C and an etching hole 155 is formed by etching the second passivation layer 154 corresponding to the transmission hole 151 . At this time, the first passivation layer 149 may be etched simultaneously with the second passivation layer 154 .
In FIG. 11E , a transparent pixel electrode 157 that contacts the drain electrode 135 through the drain contact hole is formed by depositing and patterning transparent conductive material such as indium tin oxide (ITO) or indium zinc oxide (IZO), for example, on the second passivation layer 154 .
Whereas the drain electrode is exposed by etching the first passivation layer 149 and the second passivation layer 154 respectively in a different process as in FIG. 11B and FIG. 11D , the drain contact hole can be formed by etching the first passivation layer 149 and the second passivation layer 154 , simultaneously in a single process.
A third embodiment of the present invention will be described hereinafter with reference to FIG. 12 and FIGS. 13A to 13F . FIG. 12 is a plan view illustrating a partial array substrate having a coplanar type polysilicon thin film transistor for a transflective liquid crystal display device according to the third embodiment of the present invention. FIGS. 13A to 13F are cross-sectional views taken along lines IV-IV, V-V and VI-VI of FIG. 12 illustrating a fabricating sequence of an array substrate according to the third embodiment of the present invention.
In FIG. 13A , a first insulating layer 162 , i.e., a buffer layer, is formed on the transparent insulating substrate 160 by depositing inorganic insulating material such as silicon oxide (SiO 2 ) or silicon nitride (SiN X ). The buffer layer 162 is optional. A polysilicon layer 164 is formed by depositing amorphous silicon (a-Si: H) on the buffer layer 162 and crystallizing the amorphous silicon.
In FIG. 13B , a semi-conductor layer 166 is formed by patterning the polysilicon layer 164 . The semi-conductor layer 166 has a semi-conductor layer expanded portion 167 corresponding to a pixel region “P” of FIG. 12 . The semi-conductor layer 166 can be divided into a first active region “A” that serves as an active channel and a second active region “B” that is ion doped. A second insulating layer 168 , i.e., a gate insulating layer, is formed on the substrate 160 and on the semi-conductor layer 166 by depositing inorganic insulating material such as silicon oxide (SiO 2 ) or silicon nitride (SiN X ), for example, on the substrate 160 . A gate electrode 170 over the first active region “A”, a gate line 171 connected to the gate electrode 170 and a gate pad 174 connected to one end of the gate line 171 are formed by depositing and patterning conductive metal material on the second insulating layer 168 . A storage line 172 is simultaneously formed parallel to the gate line 171 and the storage line 171 has a storage line expanded portion 173 .
In FIG. 13C , a third insulating layer 176 , i.e., interlayer insulating layer, is formed by depositing insulating material on the whole area of the substrate 160 . A first contact hole 178 a and a second contact hole 178 b , which expose the second active region “B” of the semi-conductor layer 167 are formed. A source electrode 180 and a drain electrode 182 , which contact the exposed second active region “B” are formed by depositing and patterning conductive metal such as aluminum (Al), aluminum alloys, chromium (Cr), tungsten (W), molybdenum (Mo) and niobium (Nb), for example, on the third insulating layer 176 . A data line 184 , which is connected to the source electrode 180 and vertically extended form the source electrode 180 is formed on the third insulating layer 176 . A data pad is formed at one end of the data line 184 . The data line 184 defines a pixel region “P” by crossing the gate line 171 . A polysilicon thin film transistor is formed through the above processes.
In FIG. 13D , a fourth insulating layer 188 is formed by depositing inorganic insulating material such as silicon oxide (SiO 2 ) or silicon nitride (SiN X ), for example, on the substrate 160 . The thin film transistor then undergoes a hydrogenation process. The hydrogenation process is for removing defects occurred on the surface of the active layer 166 and the fourth insulating layer 188 may be formed of silicon nitride (SiN X ) that includes hydrogen. A fifth insulating layer 190 is formed by depositing transparent organic insulating material such as benzocyclobutene (BCB) or acrylic resin, for example, on the fourth insulating layer 188 . A sixth insulating layer 200 , i.e., a barrier layer, is formed by depositing inorganic insulating material such as silicon oxide (SiO 2 ) or silicon nitride (SiN X ), for example, on the fifth insulating layer 190 .
In FIG. 13E , a reflector 202 is formed in the pixel region “P” by depositing and patterning conductive metal material such as aluminum (Al) or aluminum alloys, for example, on the barrier layer 200 . As shown in the figure, the reflector 202 is formed over the storage line expanded portion 173 . However, the reflector 202 may be formed over the thin film transistor and extended to cover the gate line 171 and the data line 184 . The reflector and the storage line expansion portion 173 constitute a reflection portion “E” of FIG. 12 in the pixel region “P” of FIG. 12 and the remaining portion of the pixel region “P” of FIG. 12 is a transmission portion “F” of FIG. 12 . Accordingly, an area ratio between the reflection portion and the transmission portion can be controlled by varying the reflector 202 and the storage line expansion portion 173 . A seventh insulating layer 205 is formed by depositing inorganic insulating material such as silicon oxide (SiO 2 ) or silicon nitride (SiN X ), for example, on the substrate 130 and on the reflector 202 . A drain contact hole 192 that exposes a part of the drain electrode 182 is formed by etching the fourth insulating layer 188 , the fifth insulating layer 190 , the sixth insulating layer 200 , i.e., the barrier layer and the seventh insulating layer 205 over the drain electrode 182 . A gate pad contact hole 194 that exposes the gate pad 174 is formed by etching laminated insulating layers from the third insulating layer 176 to the seventh insulating layer 205 over the gate pad 174 . A data pad contact hole 196 that exposes the data pad is formed by etching laminated layers from the fourth insulating layer 188 to the seventh insulating layer 205 over the data pad 186 .
An under-cut and an inversed taper, which occurs in the wall of the plurality of the contact holes can be prevented by equalizing an etching speed of the transparent organic insulating layers with the etching speed of the plurality of inorganic insulating layers. The equalizing of the etching speeds of the laminated layers is performed by adding about 65˜80% of oxygen gas to etching gas (SF 6 , CF 4 ).
In FIG. 13F , a pixel electrode 198 contacts the exposed drain electrode 182 through the drain contact hole 192 . A gate pad terminal 201 contacts the gate pad 174 through the gate pad contact hole 194 . A data pad terminal 204 contacts the data pad 186 through the data pad contact hole 196 . The pixel electrode 198 , gate pad terminal 201 and data pad terminal 204 are formed by depositing and patterning transparent conductive metal material such as indium tin oxide (ITO) or indium zinc oxide (IZO), for example, on the seventh insulating layer 205 and in the respective contact holes 192 , 194 and 196 .
The transflective liquid crystal display device of the present invention having a high aperture ratio can be manufactured through the manufacturing process described above.
As described above, an array substrate for reflective and transflective liquid crystal display devices includes a reflective electrode that avoids being formed directly on an organic insulating layer such as benzocyclobutene (BCB) by exchanging a forming order of the organic insulating layer and an inorganic insulating layer such as silicon nitride (SiN X ) or by introducing a barrier layer between the organic insulating layer and the reflective electrode. Accordingly, the array substrate with reflective electrode formed in this matter avoids the problems of the conventional art discussed above.
The invention being thus described, it will be obvious that the same may be varied in many ways. Such variations are not to be regarded as a departure from the spirit and scope of the invention, and all such modifications as would be obvious to one skilled in the art are intended to be included within the scope of the following claims. | An array substrate for a reflective liquid crystal display device, including a gate line and a data line defining a pixel region by crossing each other; a switching element at a crossing portion of the gate line and the data line; a first passivation layer covering the switching element and the data line; and formed of an inorganic insulating material; a reflective electrode on the first passivation layer, and connected to the switching element; and a second passivation layer on the reflective electrode. The second passivation layer being formed of an organic insulating material. | 6 |
BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a surgical instrument comprising a connecting device which permits, according to defined and independent positions, the rapid assembly and/or dismantling of the mobile cutting element and its actuating grip.
The connecting device is intended for surgical instruments comprising cutting elements which slide relative to one another.
The connecting device is more particularly applicable to surgical instruments comprising a fixed cutting element and a mobile cutting element which are actuated by the agency of an elastically loaded mobile grip.
2. Description of the Related Art
The applicant has filed patent applications FR 98/05 689 and FR 98/05 690 in France relating to a surgical instrument and a connecting device.
The surgical instrument possesses a main body on which a mobile clamping jaw slides by the agency of an elastically loaded grip.
The main body is formed by a fixed grip which is extended by an elongate support forming a fixed clamping jaw. The mobile clamping jaw, which is actuated by means of the elastically loaded grip, slides on the fixed clamping jaw in a longitudinal direction.
The fixed and mobile clamping jaws respectively possess, opposite the fixed and mobile grips, cutting means which interact with each other during the longitudinal displacements of the said mobile clamping jaw to make successive cuts in the hard bone tissue or soft tissue of a patient.
The connecting device in patent applications FR 98/05 689 and FR 98/05 690 merely permit the rapid assembly and dismantling of the mobile element without parts of the,instrument having to be withdrawn. The connecting device comprises means for the angular indexing of the,mobile grip about its axis of rotation to permit, in a given position, the positioning or withdrawal of the mobile element of the main body of the instrument.
SUMMARY OF THE INVENTION
The purpose of the connecting device according to the present invention is to improve that described in patent applications FR 98/05 689 and FR 98/05 690 in the name of the applicant so as to enable, in predefined and independent positions, both the assembly or dismantling of the mobile element and the assembly or dismantling of the mobile grip.
The connecting device for a surgical instrument according to the present invention comprises indexing means defining a first series of angular positions permitting the positioning or withdrawal of the mobile element and a second series of angular positions, independent of the first, for the assembly or dismantling of the mobile grip.
The connecting device according to the present invention possesses angular indexing means which are formed by:
an elastically loaded pivot for the pivoting of the mobile grip relative to the fixed grip of the main body of the instrument,
and guide means solidly fixed to the said mobile grip and interacting with the said pivot and a drive spindle provided on the mobile element for its longitudinal movements relative to the main body.
BRIEF DESCRIPTION OF DRAWINGS
The description which follows, having regard to the attached drawings, which are given by way of non-limiting examples, will provide a better understanding of the invention, the features which it possesses and the advantages which it is capable of providing:
FIG. 1 is a view showing a surgical instrument according to the present invention.
FIGS. 2 to 6 are views show the main body of the surgical instrument in detail.
FIGS. 7 to 14 are views showing, in detail, the mobile element sliding on the main body of the surgical instrument.
FIG. 15 is a view showing the mobile grip of the surgical instrument.
FIGS. 16 to 18 are views showing the pivot of the mobile grip on the main body of the surgical instrument.
FIG. 19 is a view showing the position of the pivot when the surgical instrument is in operation.
FIG. 20 is a view showing the position of the pivot for the positioning or withdrawal either of the mobile grip or of the mobile cutting element.
FIGS. 21 a and 22 a are views showing the extreme positions of the mobile grip on the main body for the positioning or withdrawal of the mobile cutting element when the pivot is in the position according to FIG. 20 .
FIGS. 21 b to 21 d and 22 b to 22 d are views illustrating the positions of the mobile grip and of the pin of the mobile cutting element in operation when the pivot is in the position according to FIG. 19 .
FIGS. 21 e and 22 e are views showing the extreme positions of the mobile grip on the main body during its positioning or withdrawal when the pivot is in the position according to FIG. 20
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows a surgical instrument 1 of the Kerrison forceps type, comprising a connecting device 100 which permits, in accordance with defined and independent angular positions, the rapid assembly and/or dismantling of a mobile cutting element 8 and of its actuating grip 5 .
The surgical instrument 1 comprises a main body 2 formed by a fixed grip 3 which is extended in a substantially horizontal plane by a fixed element or an elongate support 4 constituting a fixed clamping jaw.
The main body 2 comprises, at the junction between the fixed grip 3 and the fixed clamping jaw 4 , a mobile grip 5 which pivots about an elastically loaded pivot 6 .
The mobile grip 5 is connected to the fixed grip 3 by spring plates 7 which are provided between the two grips to restore the mobile grip 5 to its original position after each pivoting movement.
The fixed clamping jaw 4 of the main body 2 interacts with a mobile element or a mobile clamping jaw 8 which slides in a longitudinal direction from front to rear on the said fixed clamping jaw 4 when a force is applied to the mobile grip 5 .
The connecting device 100 comprises angular indexing means which make it possible to set the mobile grip 5 in defined and independent angular positions for the positioning or withdrawal of the mobile element 8 of the main body 2 , on the one hand, and the assembly or dismantling of the mobile grip 5 of the said body, on the other hand.
FIGS. 2 to 6 show the main body 2 which possesses, within its thickness and at the point of the junction between the grip 3 and the clamping jaw 4 , an aperture of conical profile 9 delimited by opposite and inclined surfaces 10 , 11 in order that the more open side of the said aperture faces towards the upper edge 12 of the fixed clamping jaw 4 .
The main body 2 comprises, on each side of the aperture 9 , an arcuate lug 13 which is pierced by a drilled hole 14 intended to receive the pivot 6 to guide the mobile grip 5 in rotation.
The maximum travel of the mobile grip 5 about the pivot 6 within the aperture 9 of the main body 2 is delimited by the inclined and opposite surfaces 10 , 11 , as will be more clearly seen in due course.
The fixed clamping jaw 4 possesses, towards its free end which is opposite to the end through which the aperture 9 passes, a tip 15 extending in a substantially vertical direction, either upwards or downwards relative to the longitudinal axis of the surgical instrument 1 .
The tip 15 possesses, within its thickness, a hollow 16 delimiting opposite edges 17 which are inclined relative to the upper edge 12 of the fixed clamping jaw 4 . The edges 17 of the tip 15 are machined to form cutting elements in order to cut bony fragments or soft tissue (FIG. 5 ).
The opposite edges 17 of the tip 15 are chamfered outwards at an angle α of approximately 30 degrees relative to the outer edge of the said tip (FIG. 6 ).
The fixed clamping jaw 4 is solidly fixed, at its upper edge 12 and opposite the tip 15 , to a T-shaped peg 18 allowing the longitudinal guiding of the mobile clamping jaw 8 .
Likewise, the fixed clamping jaw 4 comprises, in the vicinity of the tip 15 , another T-shaped peg 19 which improves the guiding of the mobile clamping jaw 8 over the entirety of its travel (FIGS. 3, 4 ).
Moreover, the T-shaped peg 19 possesses, towards the peg 18 , a portion 19 a of a lesser height than that envisaged for the peg 19 .
FIGS. 7 to 14 show the element, or mobile clamping jaw 8 , which comprises, at one of its ends and within its thickness, an arcuate recess 20 . Through this recess passes a drive spindle 21 which interacts with the mobile grip 5 to convert the rotary movements of the said grip into linear movement in order for the mobile clamping jaw 8 to slide on the fixed clamping jaw 4 .
The recess 20 communicates with a groove 22 which extends towards the other end of the mobile clamping jaw 8 . The groove 22 possesses, immediately in the extension of the recess 20 , opposite ribs 23 separated by an aperture 24 to form a slide which interacts with the T-shaped peg 18 of the fixed clamping jaw 4 (FIGS. 8, 9 ).
The opposite ribs 23 extend into a portion of the groove 22 to form a zone within which the peg 18 is not guided, to permit, in accordance with a defined angular position, the positioning or withdrawal of the mobile clamping jaw 8 .
The latter comprises in its inner portion a channel 25 opening opposite to the recess 20 at the position of an inclined end formed by inclined edges 26 which are machined to possess a cutting profile (FIGS. 10, 11 ).
The opposite edges 26 of the inclined end of the mobile clamping jaw 8 are chamfered outwards at an angle β of approximately 30 degrees relative to the outer edge of the said clamping jaw (FIGS. 13, 14 ).
Furthermore, the upper portions of the opposite edges 26 of the mobile clamping jaw 8 are chamfered towards the interior of the channel 25 at an angle χ of approximately 30 degrees relative to the upper edge of the said clamping jaw.
The channel 25 extends towards the recess 20 to open outwards and into the upper portion of the mobile clamping jaw 8 via an oblong opening 27 .
It will be noted that the channel 25 is designed to form a magazine making it possible to retain the bone fragments cut away by means of the chamfered edges 17 and 26 of each clamping jaw, both fixed 4 and mobile 8 .
The channel 25 possesses, in the vicinity of the inclined edges 26 and at the position of the lower edge 28 of the mobile clamping jaw 8 , opposite ribs 29 separated by an aperture 30 so as to constitute a slide which interacts with the T-shaped peg 19 of the fixed clamping jaw 4 (FIG. 11 ).
It will be noted that the channel 25 of the mobile clamping jaw 8 possesses a U-shaped profile which is open towards the lower edge 28 .
FIG. 15 shows in detail the mobile grip 5 , which possesses an angled section formed by a short first branch 31 extended by a longer second branch 46 .
The first branch 31 is extended, opposite to the second branch 46 , by a plate 32 pierced by a drilled hole 33 communicating with an oblong and open-ended aperture 34 .
The drilled hole 33 is designed with a diameter slightly greater than that envisaged for the oblong aperture 34 .
The drilled hole 33 is designed to accommodate the pivot 6 in order that the grip 5 may pivot about the latter when it is mounted on the main body 2 of the instrument 1 .
The oblong aperture 34 made in the plate 32 of the grip 5 is designed to receive the drive pin 21 passing through the recess 20 of the mobile clamping jaw 8 .
FIGS. 16 to 20 show in detail the various elements forming the pivot 6 allowing the pivoting of the mobile grip 5 relative to the main body 2 .
The pivot 6 is formed by a screw 35 having a tightening head 36 solidly fixed to a cylindrical body 37 whose end opposite the said head possesses a threaded portion 38 .
A compression spring 39 is arranged around the cylindrical body 37 so as to bear against the tightening head 36 and the main body 2 of the surgical instrument 1 , in the assembled position.
The cylindrical body of the screw 35 possesses a diameter slightly smaller than that envisaged for the drilled hole 33 , but greater than that of the oblong aperture 34 .
The cylindrical body 37 possesses, on each side of its longitudinal axis and from the head 36 towards the threaded portion 38 , a flattened portion 47 reducing in diameter or width over a part of its length.
The latter, contained between the diametrically opposed flattened portions 47 , is of a slightly smaller size than the oblong aperture 34 of the plate 32 .
The pivot 6 comprises a tightening nut 40 which interacts with the threaded portion 38 of the screw 35 .
The tightening nut 40 possesses, on its periphery, an indexing finger 41 which extends towards the head 36 of the screw 35 when the said nut is screwed onto the said screw. The indexing finger 41 is disposed in a plane parallel to that containing the pivot 6 of the mobile grip 5 .
The indexing finger 41 comprises an elongate portion 42 possessing two straight and parallel opposite faces 43 , 44 .
Opposite the indexing finger 41 , the tightening nut 40 comprises an open-ended hole 48 which interacts with a finger 49 , extending parallel to the axis of the drilled holes 14 and solidly fixed to the main body 2 for the translatory guidance of the pivot 6 (FIGS. 19 and 20 ).
The assembly of the instrument 1 comprises screwing the pivot 6 onto the main body 2 in a manner such that its tightening screw 35 provided with the spring 39 is introduced into the drilled hole 14 of the first lug 13 and then passes through the other drilled hole 14 of the second lug 13 to allow the nut 40 to be screwed onto the threaded portion 38 of the cylindrical body 37 .
The assembly of the mobile grip 5 between the two lugs 13 of the main body 2 takes place when the spring 39 of the pivot 6 is compressed to present the flattened portions 47 within the aperture 9 (FIG. 20 ).
Specifically, in this position, the nut 40 is moved away from the main body allowing the plate 32 of the grip 5 to be presented in an inclined position and bearing against the surface 11 of the aperture 9 (FIGS. 21 e ; 22 e ).
It will be noted that the flattened portions 47 f the pivot 6 interact with the aperture 34 of the late 32 until the said pivot is accommodated in the drilled hole 33 .
Locking of the grip 5 on the main body 2 is achieved when the pressure on the pivot 6 is withdrawn.
The transverse movement of the pivot 6 under the force of the spring 39 enables the flattened portions 47 of the screw 35 to be positioned outside the drilled hole 33 to prevent any communication with the aperture 34 , as a result of the difference in diameter between the latter and the screw 35 (FIG. 19 ).
The positioning of the grip 5 on the main body 2 enables the plate 32 to pass through the aperture 9 and to emerge above the upper edge 12 of the fixed clamping jaw 4 in order to present the oblong aperture 34 for the assembly of the mobile element 8 .
The positioning of the mobile clamping jaw 8 on the fixed clamping jaw 4 can only be achieved when the plate 32 of the mobile grip 5 is in the immediate vicinity of the inclined surface 10 of the aperture 9 of the main body 2 (FIGS. 21 a , 22 a ).
For this purpose, it is therefore necessary to exert further pressure to the head 36 of the screw 35 of the pivot 6 in order to compress the spring 39 and release the elongate portion 42 of the indexing finger 41 of the nut 40 (FIG. 20 ).
As soon as the portion 42 is withdrawn from its original position, the mobile grip 5 , under the force of the elastic means 7 , can pivot through a few additional degrees about its pivot 6 in order for the indexing finger 41 to bear against the branch 31 and the shoulder SO.
In this position, the plate 32 of the grip 5 is placed in the immediate vicinity of the inclined surface 10 in order for the aperture 34 to be directed towards the rear of the main body 2 so as to free its access. The position of the plate 32 allows the introduction of the drive spindle 21 passing through the recess 20 of the mobile clamping jaw 8 in the oblong aperture 34 .
It will be found that, in this position, the flattened portions 47 of the pivot 6 are not disposed parallel to the edges of the aperture 34 , thus preventing any possibility of withdrawal of the mobile grip 5 .
Simultaneously with the positioning of the spindle 21 in the aperture 34 , the T-shaped peg 18 of the fixed clamping jaw 4 is accommodated in the groove portion 22 furthest from the recess 20 of the mobile clamping jaw 8 , while the peg 19 interacts with the channel 25 provided towards the inclined end of the said mobile clamping jaw.
It is then sufficient to press lightly on the mobile grip 5 , compressing the elastic restoring means 7 , for it to pivot about the pivot 6 , thus permitting the indexing finger 41 to be restored to its original position under the action of the spring 39 .
In operation, the mobile grip 5 , solidly fixed to the plate 32 , allows the displacement of the mobile clamping jaw 8 on the fixed clamping jaw 4 between an open position, where the chamfered edges 17 and 26 are moved apart from one another, and a closed position, where the chamfered edges 17 and 26 bear against one another (FIGS. 21 b , 21 c , 21 d ; 22 b , 22 c , 22 d ).
Specifically, the angular range of movement of the mobile grip 5 within the aperture 9 of the main body 2 is limited by the indexing finger 41 of the pivot 6 to allow the translatory movement of the mobile clamping jaw 8 on the fixed clamping jaw 4 in accordance with defined longitudinal movements.
It will be noted that the grip 5 is automatically restored to its position of rest, in other words when the clamping jaws 4 and 8 are opened by the agency of the elastic restoring means 7 provided between the said mobile grip 5 and the fixed grip 3 of the main body 2 .
The transition from the open position to the closed position of the clamping jaws 4 and 8 enables the surgeon to cut fragments of bone or soft tissue by means of the chamfered edges 17 , 26 .
The pieces cut away during the successive movements of the mobile clamping jaw 8 on the fixed jaw 4 are recovered in the channel 25 to prevent their falling amid the operating area.
The profile of the peg 19 , possessing a portion 19 a of lesser height, makes it possible to prevent the build-up within the channel 25 of pieces of tissue cut away by the chamfered edges 17 , 26 .
When the channel 25 is filled with fragments of bone or soft tissue, it is possible to extract them through the oblong opening 26 made in the upper part of the mobile clamping jaw 8 .
The connecting device 100 allows the mobile clamping jaw 8 to be withdrawn from the main body 2 , independently of the mobile grip 5 , for the recovery of the fragments of bone or soft tissue, following a procedure reversing that described above for its positioning.
Specifically, it is sufficient to apply pressure to the head 36 of the screw 35 of the pivot 6 in order to compress the spring 39 and release the elongate portion 42 of the indexing finger 41 of the nut 40 from its original position between the branch 31 and the shoulder 50 (FIG. 20 ).
As soon as the portion 42 is withdrawn from its original position, the mobile grip 5 , under the force of the elastic means 7 , can pivot through a few additional degrees about its pivot 6 in order for the indexing finger 41 to bear against the branch 31 and the shoulder 50 .
In this position, the plate 32 of the grip 5 is placed in the immediate vicinity of the inclined surface 10 in order for the aperture 34 to be directed towards the rear of the main body 2 so as to free its access.
The position of the plate 32 allows the withdrawal of the spindle 21 from the oblong aperture 34 , and the simultaneous release of the ribs 23 and 29 from the plugs 18 and 19 for withdrawal of the mobile clamping jaw 8 of the main body 2 (FIGS. 21 a , 22 a ).
The mobile grip 5 may likewise be dismantled when it is necessary to carry out complete sterilization of the surgical instrument 1 .
For this purpose, it is necessary to unlock the elastic means 7 in order to release the mobile grip 5 from the fixed grip 3 of the main body 2 .
Subsequently, it is sufficient to exert pressure on the head 36 of the screw 35 of the pivot 6 in order to compress the spring 39 and release the elongate portion 42 of the indexing finger 41 of the nut 40 from its original position between the branch 31 and the shoulder 50 (FIG. 20 ).
In this position, the plate 32 of the mobile grip 5 is positioned in the immediate vicinity of the inclined surface 11 of the aperture 9 , while the flattened portions 47 of the screw 35 are disposed parallel to the edges of the oblong aperture 34 in order for the pivot 6 to be able to slide within the latter for the purpose of withdrawal of the grip 5 (FIGS. 21 e , 22 e ).
FIGS. 22 a to 22 e show an alternative embodiment of the profile of the oblong aperture 34 of the plate 32 when the surgical instrument 1 possesses no peg 18 on the main element 2 for the guiding of the mobile element 8 .
It will be noted that the oblong aperture 34 possesses, opposite the drilled hole 33 , and in accordance with its longitudinal axis, an oblong seating 51 which possesses a greater width than that envisaged for the said aperture.
Likewise, the drive spindle 21 disposed inside the recess 20 of the mobile element possesses diametrically opposed flattened portions 52 which define a spindle size which is substantially smaller than the width of the oblong aperture 34 .
By contrast, the diameter of the drive spindle 21 is greater than the width of the aperture 34 to prevent its extraction in the operating position of the surgical instrument, as explained previously (FIGS. 22 b to 22 d ).
The positioning or withdrawal of the mobile element 8 takes place in the same manner as described above, specifically in that the plate 32 must again be in the vicinity of the inclined surface 10 to allow the introduction of the drive spindle 21 in order that its flattened portions 52 are disposed parallel to the opposite edges of the oblong seating 51 .
In the operating position, it will be found that the drive spindle 21 retained in the seating 52 constitutes a means for guiding the mobile element 8 , preventing its withdrawal under the compressive forces necessary to cut away fragments of bone or soft tissue between the inclined and chamfered edges 17 , 26 .
It will be noted that the connecting device 100 according to the present invention may be provided on other surgical instruments to permit, in a given position, the positioning or the withdrawal of the mobile element 8 and of the mobile grip 5 of the said instrument. | A connecting device for a surgical instrument having at least one mobile cutting element which is reciprocally movable relative to a fixed jaw by operation of a resiliently loaded mobile grip wherein the connecting device includes an indexing mechanism which can be moved to a first position to permit mounting or removal of the mobile cutting element and a second position to permit independent mounting or removal of the mobile grip. | 0 |
RELATED APPLICATIONS
[0001] This application claims priority from earlier filed U.S. provisional application Ser. No. 60/209,332, filed Jun. 2, 2000.
FIELD OF THE INVENTION
[0002] The present invention relates generally to pressure vessels. More specifically, the present invention relates to a double acting hinge for use on the door of a pressure vessel.
BACKGROUND OF THE INVENTION
[0003] On a typical pressure vessel, such as, by way of example rather than limitation, an autoclave, the pressure vessel is provided with a door mounted on a pair of hinges. The opening to the vessel commonly requires a seal, with the seal being compressed between the door and the vessel when the door is closed and secured. Known closing mechanisms are usually employed which compress the door against the vessel, thus compressing the seal in order to provide an air tight fit. The seals are usually in the form of an 0 -ring which surrounds the opening to the vessel.
[0004] A number of concerns exist in the prior art, including ensuring proper alignment of the hinges, providing for adequate compression of the seal, and protecting the seal from damage during opening and closing of the door. Thus, there exists a continuing need for improved pressure vessel components that address one or more of the afore-mentioned concerns.
BRIEF DESCRIPTION OF THE DRAWINGS
[0005] [0005]FIG. 1 is a top plan schematic view of a pressure vessel having a door mounted to the vessel by a hinge mechanism assembled in accordance with the teachings of the present invention;
[0006] [0006]FIG. 2 is a partially exploded, fragmentary view in perspective of the pressure vessel and the hinge mechanism of FIG. 1;
[0007] [0007]FIG. 3 is an enlarged cross-sectional view of the hinge mechanism assembled in accordance with the teachings of the present invention and illustrating the device in a neutral position;
[0008] [0008]FIG. 4 is an enlarged cross-sectional view similar to FIG. 3 but illustrating the device in an inward position; and
[0009] [0009]FIG. 5 is an enlarged cross-sectional view similar to FIGS. 3 and 4 but illustrating the device in an outward position;
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0010] The embodiment described herein is not intended to be exhaustive or to limit the scope of the invention to the precise form or forms disclosed. Instead, the following embodiment has been chosen and described in order to best explain the principles of the invention and to enable others skilled in the art to follow its teachings.
[0011] Referring now to FIGS. 1 and 2 of the drawings, a hinge mechanism assembled in accordance with the teachings of the present invention is generally referred to by the reference numeral 10 . The hinge mechanism 10 is shown mounted to a pressure vessel 12 , with the hinge mechanism 10 pivotally connecting a door 14 to the pressure vessel 12 . The pressure vessel 12 defines an interior cavity 16 , with one end of the pressure vessel 12 forming a peripheral rim 18 which is arranged to receive a seal 20 , such that an interface 22 between the door 14 and the rim 18 will form a pressure tight seal. The seal 20 will preferably take the form of an O-ring seal of the type commonly employed in the art. An axis 23 extends longitudinally through the pressure vessel 12 , with the axis 23 generally defining an inward direction 23 - 1 and an outward direction 23 - 2 . It will be understood that all references to the inward and outward directions are meant to be generally parallel to the axis 23 in either one of the inward direction 23 - 1 or the outward direction 23 - 2 .
[0012] As shown in FIG. 1, one or more clamps 24 may be provided in order to secure the door 14 in the closed position of FIG. 1. Any number of commercially available clamps 24 may be employed, with the construction, function, and operation of such clamps 24 or other suitable closing mechanisms being generally well known to those of skill in the art.
[0013] Referring now to FIGS. 3 - 5 , the hinge mechanism 10 is shown therein. Although the pressure vessel 10 will typically include a pair of such hinge mechanisms 10 , only a single such hinge mechanism 10 will be described in detail herein, it being understood that a second such hinge mechanism will be substantially identical. The disclosed hinge mechanism 10 includes a housing 26 having a pair of ends 28 , 30 . In the disclosed embodiment, the housing 26 will be generally cylindrical, although other suitable shapes may be employed. An elongated rod 32 is disposed within the housing 26 such that the rod 32 will reciprocate as will be explained in greater detail below. The rod 32 includes a first end 34 and a second end 36 . The first end 34 of the rod 32 generally extends from the from the first end 28 of the housing 26 , while the second end 36 of the rod 32 generally extends from the second end 30 of the housing 26 . The first end 34 of the rod 32 includes a pivot 38 .
[0014] In the disclosed embodiment the pivot 38 may take the form of a ball rod end 40 which is attached to the first end 34 of the rod 32 , such as by threads 40 (FIG. 3). Such a ball rod end 40 is commercially available from a wide variety of sources. Alternatively, the pivot 38 may be an integral part of the rod 32 . Still alternatively, the pivot 38 may take the form of any one of many commercially available pivot assemblies.
[0015] A coil spring 42 is disposed within the housing 26 . The coil spring 42 includes a first end 44 , shown disposed toward the first end 28 of the housing 26 in FIG. 3, and a second end 46 , shown disposed toward the second end 30 of the housing 26 in FIG. 3. A first slidable coupling 48 and a second slidable coupling 50 are provided. The first and second slidable couplings 48 , 50 slidably connect the spring 42 to the rod 32 , and enable the spring 42 , the rod 32 , and the housing 26 to interact in such a way that the rod 32 will be shiftable between the neutral position shown in FIG. 3, toward the inward position shown in FIG. 4 (i.e., with the rod 32 shifted toward the right when viewing FIG. 4), and the outward position shown in FIG. 5 (i.e., with the rod 32 shifted toward the left when viewing FIG. 5).
[0016] The rod 32 includes a first shoulder 52 defined generally toward the first end 34 of the rod 32 , and further includes a second shoulder defined generally toward the second end 36 of the rod 32 . It will be noted that when the rod 32 is in the neutral position of FIG. 3, the spring 42 , by virtue of the slidable couplings 48 , 50 , engages both of the first shoulder 52 and the second shoulder 54 . The first and second shoulders 52 , 54 are separated by a central section 56 of the rod, with the central section 56 having a narrowed cross section 58 relative to a widened section 52 - 1 just beyond the first shoulder 52 and a widened section 54 - 1 just beyond the second shoulder 54 . The coil spring 42 defines a central passage 60 that extends lengthwise through the coil spring 42 . In the disclosed embodiment, the rod 32 extends through this central passage 60 .
[0017] In the disclosed embodiment, the first and second slidable couplings 48 , 50 each include a washer 62 , 64 , respectively. Each washer 62 , 64 includes a central aperture 62 - 1 , 64 - 1 , respectively, sized to fit over the narrowed cross section 58 of the central section 56 of the rod 32 . Further, each of the washers 62 , 64 is sized to abut an adjacent one of the shoulders 52 , 54 . Accordingly, each of the washers 62 , 64 will slide relative to the rod 32 along the central section 56 , with the travel of the washers 62 , 64 being limited by contact with an adjacent one of the shoulders 52 , 54 (i.e., travel of the first washer 62 is limited by contact with the first shoulder 52 , while travel of the second washer 64 is limited by contact with the second shoulder 54 ).
[0018] The housing 26 includes a first bushing 66 located at the first end 28 , and a second bushing 68 located at the second end 30 . The bushings 66 , 68 are sized to slidably receive the widened sections 52 - 1 and 54 - 1 , respectively, at the first end 34 and the second end 36 of the rod 32 . The bushing 66 includes an edge 70 disposed toward the spring 42 , while the bushing 68 also includes an edge 72 disposed toward the spring 42 . In the disclosed embodiment, the distance between the edges 70 , 72 , matches the distance between the shoulders 52 , 54 . Consequently, the rod 32 , when disposed in the neutral position of FIG. 3, will be maintained in the neutral position without having any “play” inwardly or outwardly (i.e., there will no movement of the rod 32 without the spring 42 being compressed).
[0019] Preferably, the spring 42 is in under a pre-load at all times. That is, the spring 42 is already compressed when the rod 32 is in the neutral position, with the edge 70 applying a force toward the right when viewing FIGS. 3 - 5 , and the edge 72 applying a force toward the left when viewing FIGS. 3 - 5 . This pre-load on the spring 42 helps to maintain the rod 32 in the neutral position. The amount of the pre-load may be varied, depending on to what degree the user wishes to have the hinge mechanism biased toward the neutral position. This pre-load may be achieved by choosing a spring 42 having a relaxed or unloaded length that is longer than the distance between the first and second shoulders 52 , 54 . Thus, when slidable couplings 48 , 50 are assembled on the rod 32 , such as by threading the ball rod end 40 in place (the first shoulder 52 may be formed by a portion of the ball rod end 40 ), the spring 42 will be compressed between the shoulders 52 , 54 as the shoulders are brought closer together by threading the ball rod end 40 onto the rod 32 .
[0020] In operation, the door 14 is mounted to the pivot 38 on each of the provided hinge mechanisms 10 , such as by using a pin 74 (FIG. 2) through the ball rod end 40 . Instead of the pin 74 , any suitable rod, bolt, screw, or other structure may be employed. The pins 74 will secure two pairs of flanges 76 - 1 , 76 - 2 (FIG. 2) to the ball rod end 40 at the first end 34 of the rod 32 on each of the hinge mechanisms 10 . The ball rod end 40 will serve to accommodate slight misalignment of the hinge mechanism 10 and/or slight misalignments of the flanges 76 - 1 and/or 76 - 2 . Consequently, smooth operation of the door 14 is facilitated. It will be understood that the hinge mechanisms 10 will be mounted directly to an outer portion 78 (FIGS. 1 and 2) of the pressure vessel 12 , such as by welding or bolting to any suitable mounting structure, flange, etc. (not shown), which may be formed on or attached to the outer portion 78 of the pressure vessel 12 in a known manner. It will also be noted that, when the pressure vessel 12 is being prepared for operation, the clamps 42 (or other suitable closing mechanism) will apply a generally inward force to the door 14 in order to compress the door 14 against the seal 20 , thus providing a more pressure-secure seal at the interface 22 between the door 14 and the peripheral rim 18 . This movement of the door 14 in the inward direction will cause the pin 74 to force the rod 32 in the inward direction (i.e., toward the right when viewing FIGS. 3 - 5 ).
[0021] On the other hand, when the door 14 is opened (upon release fo the clamps 42 or other suitable closing mechanism, it may be desirable that the door 14 is able to be pulled away slightly from the peripheral rim 18 , such that the door 14 may be pivoted toward the open position (shown in dotted lines in FIG. 1) without binding on one edge of the seal 20 . In order to prevent binding, the door 14 (and specifically the flanges 76 - 1 and 76 - 2 ) may be displaced slightly in the outward direction away from the adjacent portion of the rim 18 . This outward movement of the door 14 will cause the pin 74 to force the rod 32 in the outward direction (i.e., toward the left when viewing FIGS. 3 - 5 ).
[0022] Referring again to FIG. 3, when the rod 32 is disposed in the neutral position the spring 42 is preferably at least partially compressed in order to prevent play as outlined above, and in order to be under a pre-load. Thus, the first washer 62 is biased against the inner edge 70 of the first bushing 66 , and is also biased against the first shoulder 52 . Similarly, the second washer 64 is biased against the inner edge 72 of the second bushing 68 , and is also biased against the second shoulder 54 .
[0023] When the door 14 of the pressure vessel 12 is closed and drawn inwardly by the clamps 42 , the rod 32 will shift inwardly by virtue of the inward force applied to the first end 34 by the pin 74 . Consequently, the rod 32 will shift toward the position of FIG. 4. When this happens, the second washer 64 (abutting the edge 72 of the bushing 68 ) moves along the central section 56 as the shoulder 54 and the widened section 54 - 1 slide through the bushing 68 . Thus, the hinge mechanism 10 accommodates inward movement of the door 14 . Also, by virtue of the washer 62 abutting the shoulder 52 and the washer 64 abutting the edge 72 of the bushing 68 , the spring 42 applies an outward biasing force to the rod 32 . This outward biasing force varies with distance as the rod moves, and may be calculated using well known engineering principles based on the spring constant for the chosen spring.
[0024] On the other hand, when the door 14 of the pressure vessel 12 is to be opened, and it is desired to pull the door 14 away from the seal 20 , the rod 32 will shift outwardly by virtue of the outward force applied to the first end 34 by the pin 74 (passing through the neutral position of FIG. 3). Consequently, the rod 32 will shift toward the position of FIG. 5. When this happens, the first washer 612 (abutting the edge 70 of the bushing 66 ) moves along the central section 56 as the shoulder 52 and the widened section 52 - 1 slide through the bushing 66 . Thus, the hinge mechanism 10 accommodates outward movement of the door 14 . Also, by virtue of the washer 64 abutting the shoulder 54 and the washer 62 abutting the edge 70 of the bushing 66 , the spring 42 applies an inward biasing force to the rod 32 . Again, this outward biasing force varies with distance as the rod moves, and may be calculated using the well known engineering principles based on the spring constant for the chosen spring.
[0025] According to the disclosed embodiment, the hinge mechanism provides a double action spring effect with a single spring 42 . The single, double acting spring permits the door 14 to be compressed onto the seal 20 , and further permits the door 14 to pull away from the seal 20 upon opening the door 14 , such that the seal 20 is not damaged by the door 14 as might occur with more convention hinges. Preferably, the spring is provided with a relatively high pre-load. Further, the ball rod ends 40 provide better alignment of the door 14 with respect to the hinges 10 and the vessel 12 .
[0026] Numerous modifications and alternative embodiments of the invention will be apparent to those skilled in the art in view of the foregoing description. Accordingly, this description is to be construed as illustrative only and is for the purpose of teaching those skilled in the art the best mode of carrying out the invention. The details of the structure may be varied substantially without departing from the spirit of the invention, and the exclusive use of all modifications which come within the scope of the appended claims is reserved. | A hinge mechanism for joining a door to a vessel is disclosed. The hinge mechanism includes a housing having a first end and a second end, and a rod reciprocally disposed in the housing, with the rod having a first end adapted to pivotally engage the door and further having a second end. A spring is disposed within the housing. A first coupling slidably connects a first end of the spring to the first end of the rod, and a second coupling slidably connects a second end of the spring to the second end of the rod. The spring, the housing, and the first and second couplings cooperate to permit movement of the rod between an outward position, an inward position, and a neutral position between the outward position and the inward position. The spring is arranged to bias the rod toward the neutral position. | 8 |
[0001] This application is a continuation of U.S. patent application Ser. No. 13/301,610, filed on Nov. 21, 2011, which is currently allowed, and is a continuation of U.S. patent application Ser. No. 11/865,685, filed on Oct. 1, 2007, (now U.S. Pat. No. 8,130,770), and is a continuation of U.S. patent application Ser. No. 10/187,132, filed on Jun. 28, 2002, (now U.S. Pat. No. 7,277,413) and which claims priority from:
[0002] [1] U.S. Provisional Application Ser. No. 60/302,661, filed Jul. 5, 2001, entitled “HCF ACCESS THROUGH TIERED CONTENTION,”
[0003] [2] U.S. Provisional Application Ser. No. 60/304,122, filed Jul. 11, 2001, entitled “HCF ACCESS THROUGH TIERED CONTENTION,” and
[0004] [3] U.S. Provisional Application Ser. No. 60/317,933 filed Sep. 10, 2001, entitled “HCF ACCESS AND OVERLAPPED BSS MITIGATION,” all of which are incorporated herein by reference.
RELATED APPLICATIONS
[0005] This patent application is related to the copending regular U.S. patent application Ser. No. 09/985,257, filed Nov. 2, 2001, by Mathilde Benveniste, entitled “TIERED CONTENTION MULTIPLE ACCESS (TCMA): A METHOD FOR PRIORITY-BASED SHARED CHANNEL ACCESS,” (now U.S. Pat. No. 7,095,754) which is incorporated by reference.
FIELD OF THE INVENTION
[0006] The invention disclosed broadly relates to telecommunications methods and more particularly relates to Quality of Service (QoS) management in multiple access packet networks.
BACKGROUND OF THE INVENTION
Wireless Local Area Networks (WLANS)
[0007] Wireless local area networks (WLANs) generally operate at peak speeds of between 10 to 100 Mbps and have a typical range of 100 meters. Single cell Wireless LANs, are suitable for small single-floor offices or stores. A station in a wireless LAN can be a personal computer, a bar code scanner, or other mobile or stationary device that uses a wireless network interface card (NIC) to make the connection, over the RF link to other stations in the network. The single-cell wireless LAN provides connectivity within radio range between wireless stations. An access point allows connections via the backbone network, to wired network-based resources, such as servers. A single cell wireless LAN can typically support up to 25 users and still keep network access delays at an acceptable level. Multiple cell wireless LANs provide greater range than does a single cell, by means of a set of access points and a wired network backbone to interconnect a plurality of single cell LANs. Multiple cell wireless LANs can cover larger multiple-floor buildings. A mobile laptop computer or data collector with a wireless network interface card (NIC) can roam within the coverage area while maintaining a live connection to the backbone network.
[0008] Wireless LAN specifications and standards include the IEEE 802.11 Wireless LAN Standard and the HIPERLAN Type 1 and Type 2 Standards. The IEEE 802.11 Wireless LAN Standard is published in three parts as IEEE 802.11-1999; IEEE 802.11a-1999; and IEEE 802.11b-1999, which are available from the IEEE, Inc. web site http://grouper.ieee.org/groups/802/11. An overview of the HIPERLAN Type 1 principles of operation is provided in the publication HIPERLAN Type 1 Standard, ETSI ETS 300 652 , WA2 Dec. 1997. An overview of the HIPERLAN Type 2 principles of operation is provided in the Broadband Radio Access Networks (BRAN), HIPERLAN Type 2; System Overview, ETSI TR 101 683 VI.I.1 (2000-02) and a more detailed specification of its network architecture is described in HIPERLAN Type 2, Data Link Control (DLC) Layer; Part 4. Extension for Home Environment, ETSI TS 101 761-4 V1.2.1 (2000-12). A subset of wireless LANs is Wireless Personal Area Networks (PANs), of which the Bluetooth Standard is the best known. The Bluetooth Special Interest Group, Specification Of The Bluetooth System, Version 1.1, Feb. 22, 2001, describes the principles of Bluetooth device operation and communication protocols.
[0009] The IEEE 802.11 Wireless LAN Standard defines at least two different physical (PHY) specifications and one common medium access control (MAC) specification. The IEEE 802.11(a) Standard is designed to operate in unlicensed portions of the radio spectrum, usually either in the 2.4 GHz Industrial, Scientific, and Medical (ISM) band or the 5 GHz Unlicensed-National Information Infrastructure (U-NII) band. It uses orthogonal frequency division multiplexing (OFDM) to deliver up to 54 Mbps data rates. The IEEE 802.11(b) Standard is designed for the 2.4 GHz ISM band and uses direct sequence spread spectrum (DSSS) to deliver up to 11 Mbps data rates. The IEEE 802.11 Wireless LAN Standard describes two major components, the mobile station and the fixed access point (AP). IEEE 802.11 networks can also have an independent configuration where the mobile stations communicate directly with one another, without support from a fixed access point.
[0010] A single cell wireless LAN using the IEEE 802.11 Wireless LAN Standard is an Independent Basic Service Set (IBSS) network. An IBSS has an optional backbone network and consists of at least two wireless stations. A multiple cell wireless LAN using the IEEE 802.11 Wireless LAN Standard is an Extended Service Set (ESS) network. An ESS satisfies the needs of large coverage networks of arbitrary size and complexity.
[0011] Each wireless station and access point in an IEEE 802.11 wireless LAN implements the MAC layer service, which provides the capability for wireless stations to exchange MAC frames. The MAC frame transmits management, control, or data between wireless stations and access points. After a station forms the applicable MAC frame, the frame's bits are passed to the Physical Layer for transmission.
[0012] Before transmitting a frame, the MAC layer must first gain access to the network. Three interframe space (IFS) intervals defer an IEEE 802.11 station's access to the medium and provide various levels of priority. Each interval defines the duration between the end of the last symbol of the previous frame, to the beginning of the first symbol of the next frame. The Short Interframe Space (SIFS) provides the highest priority level by allowing some frames to access the medium before others, such as an Acknowledgement (ACK) frame, a Clear to Send (CTS) frame, or a subsequent fragment burst of a previous data frame. These frames require expedited access to the network to minimize frame retransmissions.
[0013] The Priority Interframe Space (PIFS) is used for high priority access to the medium during the contention-free period. The point coordinator in the access point connected to backbone network, controls the priority-based Point Coordination Function (PCF) to dictate which stations in cell can gain access to the medium. The point coordinator in the access point sends a contention-free poll frame to a station, granting the station permission to transmit a single frame to any destination. All other stations in the cell can only transmit during contention-free period if the point coordinator grants them access to the medium. The end of the contention-free period is signaled by the contention-free end frame sent by the point coordinator, which occurs when time expires or when the point coordinator has no further frames to transmit and no stations to poll.
[0014] The distributed coordination function (DCF) Interframe Space (DIFS) is used for transmitting low priority data frames during the contention-based period. The DIFS spacing delays the transmission of lower priority frames to occur later than the priority-based transmission frames. An Extended Interframe Space (EIFS) goes beyond the time of a DIFS interval, as a waiting period when a bad reception occurs. The EIFS interval provides enough time for the receiving station to send an acknowledgment (ACK) frame.
[0015] During the contention-based period, the distributed coordination function (DCF) uses the Carrier-Sense Multiple Access With Collision Avoidance (CSMA/CA) contention-based protocol, which is similar to IEEE 802.3 Ethernet. The CSMA/CA protocol minimizes the chance of collisions between stations sharing the medium, by waiting a random backoff interval, if the station's sensing mechanism indicates a busy medium. The period of time immediately following traffic on the medium is when the highest probability of collisions occurs, especially where there is high utilization. Once the medium is idle, CSMA/CA protocol causes each station to delay its transmission by a random backoff time, thereby minimizing the chance it will collide with those from other stations.
[0016] The CSMA/CA protocol computes the random backoff time as the product of a constant, the slot time, times a pseudo-random number RN which has a range of values from zero to a collision window CW. The value of the collision window for the first try to access the network is CW1, which yields the first try random backoff time. If the first try to access the network by a station fails, then the CSMA/CA protocol computes a new CW by doubling the current value of CW as CW2=CW 1 times 2. The value of the collision window for the second try to access the network is CW2, which yields the second try random backoff time. This process by the CSMA/CA protocol of increasing the delay before transmission is called binary exponential backoff. The reason for increasing CW is to minimize collisions and maximize throughput for both low and high network utilization. Stations with low network utilization are not forced to wait very long before transmitting their frame. On the first or second attempt, a station will make a successful transmission. However, if the utilization of the network is high, the CSMA/CA protocol delays stations for longer periods to avoid the chance of multiple stations transmitting at the same time. If the second try to access the network fails, then the CSMA/CA protocol computes a new CW by again doubling the current value of CW as CW3=CW1 times 4. The value of the collision window for the third try to access the network is CW3, which yields the third try random backoff time. The value of CW increases to relatively high values after successive retransmissions, under high traffic loads. This provides greater transmission spacing between stations waiting to transmit.
Collision Avoidance Techniques
[0017] Four general collision avoidance approaches have emerged: [1] Carrier Sense Multiple Access (CSMA) [see, F. Tobagi and L. Kleinrock, “Packet Switching in Radio Channels Part I—Carrier Sense Multiple Access Models and their Throughput Delay Characteristics”, IEEE Transactions on Communications, Vol 23, No 12, Pages 1400-1416, 1975], [2] Multiple Access Collision Avoidance (MACA) [see, P. Karn, “MACA—A New Channel Access Protocol for Wireless Ad-Hoc Networks”, Proceedings of the ARRL/CRRL Amateur Radio Ninth Computer Networking Conference, Pages 134-140, 1990], [3] their combination CSMA/CA, and [4] collision avoidance tree expansion.
[0018] CSMA allows access attempts after sensing the channel for activity. Still, simultaneous transmit attempts lead to collisions, thus rendering the protocol unstable at high traffic loads. The protocol also suffers from the hidden terminal problem.
[0019] The latter problem was resolved by the MACA protocol, which involves a three-way handshake [P. Karn, supra]. The origin node sends a request to send (RTS) notice of the impending transmission. A response is returned by the destination if the RTS notice is received successfully and the origin node proceeds with the transmission. This protocol also reduces the average delay as collisions are detected upon transmission of merely a short message, the RTS. With the length of the packet included in the RTS and echoed in the clear to send (CTS) messages, hidden terminals can avoid colliding with the transmitted message. However, this prevents the back-to-back re-transmission in case of unsuccessfully transmitted packets. A five-way handshake MACA protocol provides notification to competing sources of the successful termination of the transmission. [see, V. Bharghavan, A. Demiers, S. Shenker, and L. Zhang, “MACAW: A media access protocol for wireless LANs, SIGCOMM '94, Pages 212-225, ACM, 1994.]
[0020] CSMA and MACA are combined in CSMA/CA, which is MACA with carrier sensing, to give better performance at high loads. A four-way handshake is employed in the basic contention-based access protocol used in the Distributed Coordination Function (DCF) of the IEEE 802.11 Standard for Wireless LANs. [see, IEEE Standards Department, D3, “Wireless Medium Access Control and Physical Layer WG,” IEEE Draft Standard P802.11 Wireless LAN, January 1996.]
[0021] Collisions can be avoided by splitting the contending terminals before transmission is attempted. In the pseudo-Bayesian control method, each terminal determines whether it has permission to transmit using a random number generator and a permission probability “p” that depends on the estimated backlog. [see, R. L. Rivest, “Network control by Bayesian Broadcast”, IEEE Trans. Inform. Theory, Vol IT 25, pp. 505-515, September 1979]
[0022] To resolve collisions, subsequent transmission attempts are typically staggered randomly in time using the following two approaches: binary tree and binary exponential backoff.
[0023] Upon collision, the binary tree method requires the contending nodes to self-partition into two groups with specified probabilities. This process is repeated with each new collision. The order in which contending nodes transmit is determined either by serial or parallel resolution of the tree. [see, J. L. Massey, “Collision-resolution algorithms and random-access communications”, in Multi-User Communication Systems, G. Longo (ed.), CISM Courses and Lectures No. 265. New York: Springer 1982, pp. 73-137.]
[0024] In the binary exponential backoff approach, a backoff counter tracks the number of pauses and hence the number of completed transmissions before a node with pending packets attempts to seize the channel. A contending node initializes its backoff counter by drawing a random value, given the backoff window size. Each time the channel is found idle, the backoff counter is decreased and transmission is attempted upon expiration of the backoff counter. The window size is doubled every time a collision occurs, and the backoff countdown starts again. [see, A. Tanenbaum, Computer Networks, 3 rd ed., Upper Saddle River, N.J., Prentice Hall, 1996] The Distributed Coordination Function (DCF) of the IEEE 802.11 Standard for Wireless LANs employs a variant of this contention resolution scheme, a truncated binary exponential backoff, starting at a specified window and allowing up to a maximum backoff range below which transmission is attempted. [IEEE Standards Department, D3, supra] Different backoff counters may be maintained by a contending node for traffic to specific destinations. [Bharghavan, supra] In the IEEE 802.11 Standard, the channel is shared by a centralized access protocol, the Point Coordination Function (PCF), which provides contention-free transfer based on a polling scheme controlled by the access point (AP) of a basic service set (BSS). [IEEE Standards Department, D3, supra] The centralized access protocol gains control of the channel and maintains control for the entire contention-free period by waiting a shorter time between transmissions than the stations using the Distributed Coordination Function (DCF) access procedure. Following the end of the contention-free period, the DCF access procedure begins, with each station contending for access using the CSMA/CA method.
[0025] The 802.11 MAC Layer provides both contention and contention-free access to the shared wireless medium. The MAC Layer uses various MAC frame types to implement its functions of MAC management, control, and data transmission. Each station and access point on an 802.11 wireless LAN implements the MAC Layer service, which enables stations to exchange packets. The results of sensing the channel to determine whether the medium is busy or idle, are sent to the MAC coordination function of the station. The MAC coordination also carries out a virtual carrier sense protocol based on reservation information found in the Duration Field of all frames. This information announces to all other stations, the sending station's impending use of the medium. The MAC coordination monitors the Duration Field in all MAC frames and places this information in the station's Network Allocation Vector (NAV) if the value is greater than the current NAV value. The NAV operates similarly to a timer, starting with a value equal to the Duration Field of the last frame transmission sensed on the medium, and counting down to zero. After the NAV reaches zero, the station can transmit, if its physical sensing of the channel indicates a clear channel.
[0026] At the beginning of a contention-free period, the access point senses the medium, and if it is idle, it sends a Beacon packet to all stations. The Beacon packet contains the length of the contention-free interval. The MAC coordination in each member station places the length of the contention-free interval in the station's Network Allocation Vector (NAV), which prevents the station from taking control of the medium until the end of the contention-free period. During the contention-free period, the access point can send a polling message to a member station, enabling it to send a data packet to any other station in the BSS wireless cell.
Quality of Service (QoS)
[0027] Quality of service (QoS) is a measure of service quality provided to a customer. The primary measures of QoS are message loss, message delay, and network availability. Voice and video applications have the most rigorous delay and loss requirements. Interactive data applications such as Web browsing have less restrained delay and loss requirements, but they are sensitive to errors. Non-real-time applications such as file transfer, Email, and data backup operate acceptably across a wide range of loss rates and delay. Some applications require a minimum amount of capacity to operate at all, for example, voice and video. Many network providers guarantee specific QoS and capacity levels through the use of Service-Level Agreements (SLAs). An SLA is a contract between an enterprise user and a network provider that specifies the capacity to be provided between points in the network that must be delivered with a specified QoS. If the network provider fails to meet the terms of the SLA, then the user may be entitled a refund. The SLA is typically offered by network providers for private line, frame relay, ATM, or Internet networks employed by enterprises.
[0028] The transmission of time-sensitive and data application traffic over a packet network imposes requirements on the delay or delay jitter, and the error rates realized; these parameters are referred to generically as the QoS (Quality of Service) parameters. Prioritized packet scheduling, preferential packet dropping, and bandwidth allocation are among the techniques available at the various nodes of the network, including access points, that enable packets from different applications to be treated differently, helping achieve the different quality of service objectives. Such techniques exist in centralized and distributed variations. The concern herein is with distributed mechanisms for multiple access in cellular packet networks or wireless ad hoc networks.
[0029] Management of contention for the shared transmission medium must reflect the goals sought for the performance of the overall system. For instance, one such goal would be the maximization of goodput (the amount of good data transmitted as a fraction of the channel capacity) for the entire system, or of the utilization efficiency of the RF spectrum; another is the minimization of the worst-case delay. As multiple types of traffic with different performance requirements are combined into packet streams that compete for the same transmission medium, a multi-objective optimization is required.
[0030] Ideally, one would want a multiple access protocol that is capable of effecting packet transmission scheduling as close to the optimal scheduling as possible, but with distributed control. Distributed control implies both some knowledge of the attributes of the competing packet sources and limited control mechanisms.
[0031] To apply any scheduling algorithm in random multiple access, a mechanism must exist that imposes an order in which packets will seize the medium. For distributed control, this ordering must be achieved independently, without any prompting or coordination from a control node. Only if there is a reasonable likelihood that packet transmissions will be ordered according to the scheduling algorithm, can one expect that the algorithm's proclaimed objective will be attained.
[0032] The above cited, copending patent application by Mathilde Benveniste, entitled “Tiered Contention Multiple Access (TCMA): A Method for Priority-Based Shared Channel Access”, describes the Tiered Contention Multiple Access (TCMA) distributed medium access protocol that schedules transmission of different types of traffic based on their QoS service quality specifications. This protocol makes changes to the contention window following the transmission of a frame, and therefore is also called Extended-DCF (E-DCF). During the contention window, the various stations on the network contend for access to the network. To avoid collisions, the MAC protocol requires that each station first wait for a randomly-chosen time period, called an arbitration time. Since this period is chosen at random by each station, there is less likelihood of collisions between stations. TCMA uses the contention window to give higher priority to some stations than to others. Assigning a short contention window to those stations that should have higher priority ensures that in most cases, the higher-priority stations will be able to transmit ahead of the lower-priority stations. TCMA schedules transmission of different types of traffic based on their QoS service quality specifications. As seen in FIG. 1 , which depicts the tiered contention mechanism, a station cannot engage in backoff countdown until the completion of an idle period of length equal to its arbitration time.
[0033] The above cited, copending patent application by Mathilde Benveniste also applies TCMA to the use of the wireless access point as a traffic director. This application of the TCMA protocol is called the hybrid coordination function (HCF). In HCF, the access point uses a polling technique as the traffic control mechanism. The access point sends polling packets to a succession of stations on the network. The individual stations can reply to the poll with a packet that contains not only the response, but also any data that needs to be transmitted. Each station must wait to be polled. The access point establishes a polling priority based on the QoS priority of each station.
[0034] What is needed in the prior art is a way to apply the hybrid coordination function (HCF) to wireless cells that have overlapping access points contending for the same medium.
SUMMARY OF THE INVENTION
[0035] In accordance with the invention, the Tiered Contention Multiple Access (TCMA) protocol is applied to wireless cells which have overlapping access points contending for the same medium. Quality of Service (QoS) support is provided to overlapping access points to schedule transmission of different types of traffic based on the service quality specifications of the access points.
[0036] The inventive method reduces interference in a medium between overlapping wireless LAN cells, each cell including an access point station and a plurality of member stations. In accordance with the invention, the method assigns to a first access point station in a first wireless LAN cell, a first scheduling tag. The scheduling tag has a value that determines an accessing order for the cell in a transmission frame, with respect to the accessing order of other wireless cells. The scheduling tag value is deterministically set. The scheduling tag value can be permanently assigned to the access point by its manufacturer, it can be assigned by the network administrator at network startup, it can be assigned by a global processor that coordinates a plurality of wireless cells over a backbone network, it can be drawn from a pool of possible tag values during an initial handshake negotiation with other wireless stations, or it can be cyclically permuted in real-time, on a frame-by-frame basis, from a pool of possible values, coordinating that cyclic permutation with that of other access points in other wireless cells.
[0037] An access point station in a wireless cell signals the beginning of an intra-cell contention-free period for member stations in its cell by transmitting a beacon packet. The duration of the intra-cell contention-free period is deterministically set. The member stations in the cell store the intra-cell contention-free period value as a Network Allocation Vector (NAV). Each member station in the cell decrements the value of the NAV in a manner similar to other backoff time values, during which it will delay accessing the medium.
[0038] In accordance with the invention, the method assigns to the first access point station, a first inter-cell contention-free period value, which gives notice to any other cell receiving the beacon packet, that the first cell has seized the medium for the period of time represented by the value. The inter-cell contention-free period value is deterministically set. Further in accordance with the invention, any station receiving the beacon packet immediately broadcasts a contention-free time response (CFTR) packet containing a copy of the first inter-cell contention-free period value. In this manner, the notice is distributed to a second access point station in an overlapping, second cell. The second access point stores the first inter-cell contention-free period value as an Inter-BSS Network Allocation Vector (IBNAV). The second access point decrements the value of IBNAV in a manner similar to other backoff time values, during which it will delay accessing the medium.
[0039] Still further in accordance with the invention, the method also assigns to first member stations in the first cell, a first shorter backoff value for high Quality of Service (QoS) data and a first longer backoff value for lower QoS data. The backoff time is the interval that a member station waits after the expiration of the contention-free period, before the member station contends for access to the medium. Since more than one member station in a cell may be competing for access, the actual backoff time for a particular station can be selected as one of several possible values. In one embodiment, the actual backoff time for each particular station is deterministically set, so as to reduce the length of idle periods. In another embodiment, the actual backoff time for each particular station is randomly drawn from a range of possible values between a minimum delay interval to a maximum delay interval. The range of possible backoff time values is a contention window. The backoff values assigned to a cell may be in the form of a specified contention window. High QoS data is typically isochronous data such as streaming video or audio data that must arrive at its destination at regular intervals. Low QoS data is typically file transfer data and email, which can be delayed in its delivery and yet still be acceptable. The Tiered Contention Multiple Access (TCMA) protocol coordinates the transmission of packets within a cell, so as to give preference to high QoS data over low QoS data, to insure that the required quality of service is maintained for each type of data.
[0040] The method similarly assigns to a second access point station in a second wireless LAN cell that overlaps the first cell, a second contention-free period value longer than the first contention-free period value. The method also assigns to second member stations in the second cell, a second shorter backoff value for high QoS data and a second longer backoff value for lower QoS data. The first and second cells are considered to be overlapped when one or more stations in the first cell inadvertently receive packets from member stations or the access point of the other cell. The invention reduces the interference between the overlapped cells by coordinating the timing of their respective transmissions, while maintaining the TCMA protocol's preference for the transmission of high QoS data over low QoS data in each respective cell.
[0041] During the operation of two overlapped cells, the method transmits a first beacon packet including the intra-cell contention-free period value (the increment to the NAV) and inter-cell contention-free period value (the CFTR), from the first access point to the first member stations in the first cell. The beacon packet is received by the member stations of the first cell and can be inadvertently received by at least one overlapped member station of the second cell. Each member station in the first cell increments its NAV with the intra-cell contention-free period value and stores the inter-cell contention-free period value as the CFTR.
[0042] In accordance with the invention, each station that receives the first beacon packet, immediately responds by transmitting a first contention-free time response (CFTR) packet that contains a copy of the inter-cell contention-free period value (CFTR). A CFTR packet is transmitted from the first member stations in the first cell and also by the overlapped member stations of the second cell. The effect of the transmission of CFTR packets from member stations in the second cell is to alert the second access point and the second member stations in the second cell, that the medium has been seized by the first access point in the first cell. When the second access point in the second cell receives the CFTR packet it stores a copy of the inter-cell contention-free period value as the IBNAV.
[0043] Similar to a station's Network Allocation Vector (NAV), a first IBNAV is set at the second access point to indicate the time the medium will be free again. Also similar to the NAV, the first IBNAV is decremented with each succeeding slot, similar to the decrementing of other backoff times. When the second access point receives the first IBNAV representing the first cell's contention-free period value, the second access point must respect the first IBNAV value and delay transmitting its beacon packet and the exchange of other packets in the second cell until the expiration of the received, first IBNAV.
[0044] When the second access point has decremented the first IBNAV to zero, the second access point transmits its second beacon packet including its second contention-free period values of NAV and a second IBNAV, to the second member stations in the second cell. Each station that receives the second beacon packet immediately responds by transmitting a second contention-free time response (CFTR) packet that contains a copy of the second IBNAV inter-cell contention-free period value. The second CFTR packet is transmitted from the second member stations in the second cell and also by the overlapped member stations of the first cell. The effect of the transmission of the second CFTR packets from overlapped member stations in the first cell is to alert the first access point and the first member stations in the first cell, that the medium has been seized by the second access point in the second cell. When the first access point in the first cell receives the CFTR packet it stores the a copy of the second IBNAV inter-cell contention-free period value, to indicate the time the medium will be free again. The second IBNAV is decremented with each succeeding frame, similar to the decrementing of other backoff times.
[0045] The second member stations in the second cell wait for completion of the countdown of their NAVs to begin the TCMA protocol of counting down the second shorter backoff for high QoS data and then transmitting second high QoS data packets.
[0046] Meanwhile, the first access point in the first cell waits for completion of the countdown of the second IBNAV inter-cell contention-free period before starting the countdown of its own NAV for its own intra-cell contention-free period. The first member stations in the first cell wait for the countdown of their NAVs, to begin the TCMA protocol of counting down the first longer backoff for low QoS data and then transmitting first low QoS data.
[0047] Meanwhile the second member stations are waiting for the TCMA protocol of counting down the second longer backoff for lower QoS data before transmitting the second lower QoS data.
[0048] In this manner, interference in a medium between overlapping wireless LAN cells is reduced.
[0049] Potential collisions between cells engaged in centralized access can be averted or resolved by the TCMA protocol. In accordance with the invention, deterministically set backoff delays are used, which tend to reduce the length of the idle periods. The possibility of coincident or overlapping contention-free periods between neighboring cells is eliminated through the use of an “interference sensing” method employing a new frame.
[0050] The invention enables communication of channel occupancy information to neighboring access points. When a beacon packet is transmitted, and before transmission of any other data or polling packets, all stations hearing the beacon will respond by sending a frame, the contention-free time response (CFTR), that will contain the duration of the contention-free period found in the beacon. An access point in neighboring cells, or stations attempting contention-based channel access, which receive this message from a station in the cell overlapping region, are thus alerted that the channel has been seized by an access point. Similar to a station's Network Allocation Vector (NAV), an Inter-Cell Network Allocation Vector at the access point accordingly indicates when the time the channel will be free again. Unless the Inter-Cell Network Allocation Vector is reset, the access point will decrease its backoff value only after the expiration of the Inter-Cell Network Allocation Vector, according to the backoff countdown rules.
[0051] In another aspect of the invention, potential collisions between different access points engaged in centralized access cart be averted or resolved by using deterministic backoff delays, which avoid collisions between access points, and eliminate gaps between consecutive poll/response exchanges or contention-free bursts (CFBs) between the access point and its associated stations.
[0052] The resulting invention applies the Tiered Contention Multiple Access (TCMA) protocol to wireless cells which have overlapping access points contending for the same medium.
DESCRIPTION OF THE FIGURES
[0053] FIG. 1 depicts the tiered contention mechanism.
[0054] FIG. 1A through 1J show the interaction of two wireless LAN cells which have overlapping access points contending for the same medium, in accordance with the invention.
[0055] FIG. 1K shows a timing diagram for the interaction of two wireless LAN cells in FIG. 1A through 1J , in accordance with the invention.
[0056] FIG. 1L shows the IEEE 802.11 packet structure for a beacon packet, including the increment to the NAV period and the CFTR period, in accordance with the invention.
[0057] FIG. 1M shows the IEEE 802.11 packet structure for a CFTR packet, including the CFTR period, in accordance with the invention.
[0058] FIG. 2 illustrates the ordering of transmissions from three groups of BSSs.
[0059] FIG. 3 illustrates how three interfering BSSs share the same channel for two consecutive frames.
[0060] FIG. 4 illustrates how three interfering BSSs, each with two types of traffic of different priorities, share the same channel in two consecutive frames.
[0061] FIGS. 5 ( 5 a and 5 b ) illustrates the possible re-use of tags.
[0062] FIG. 6 illustrates the deterministic post-backoff.
[0063] FIG. 7 shows the relationships of repeating sequences of CFBs.
[0064] FIG. 8 illustrates the role of pegging in a sequence of CFBs by three overlapping access points.
[0065] FIG. 9 illustrates the start-up procedure for a new access point, HC2, given an existing access point, HC1.
[0066] FIG. 10 shows the relationship of repeating sequences of Tier I CFBs.
[0067] FIG. 11 illustrates the start-up procedure for a new access point, HC2, given an existing access point, HC 1 .
DISCUSSION OF THE PREFERRED EMBODIMENT
[0068] The invention disclosed broadly relates to telecommunications methods and more particularly relates to Quality-of-Service (QoS) management in multiple access packet networks. Several protocols, either centralized or distributed can co-exist on the same channel through the Tiered Contention Multiple Access method. The proper arbitration time to be assigned to the centralized access protocol must satisfy the following requirements: (i) the centralized access protocol enjoys top priority access, (ii) once the centralized protocol seizes the channel, it maintains control until the contention-free period ends, (iii) the protocols are backward compatible, and (iv) Overlapping Basic Service Sets (OBSSs) engaged in centralized-protocol can share the channel efficiently.
[0069] In accordance with the invention, the Tiered Contention Multiple Access (TCMA) protocol is applied to wireless cells which have overlapping access points contending for the same medium. Quality of Service (QoS) support is provided to overlapping access points to schedule transmission of different types of traffic based on the service quality specifications of the access points.
[0070] The inventive method reduces interference in a medium between overlapping wireless LAN cells, each cell including an access point station and a plurality of member stations. FIGS. 1A through 1J show the interaction of two wireless LAN cells which have overlapping access points contending for the same medium, in accordance with the invention. The method assigns to a first access point station in a first wireless LAN cell, a first scheduling tag. The scheduling tag has a value that determines an accessing order for the cell in a transmission frame, with respect to the accessing order of other wireless cells. The scheduling tag value is deterministically set. The scheduling tag value can be permanently assigned to the access point by its manufacturer, it can be assigned by the network administrator at network startup, it can be assigned by a global processor that coordinates a plurality of wireless cells over a backbone network, it can be drawn from a pool of possible tag values during an initial handshake negotiation with other wireless stations, or it can be cyclically permuted in real-time, on a frame-by-frame basis, from a pool of possible values, coordinating that cyclic permutation with that of other access points in other wireless cells.
[0071] The interaction of the two wireless LAN cells 100 and 150 in FIGS. 1A through 1J is shown in the timing diagram of FIG. 1K . The timing diagram of FIG. 1K begins at instant T0, goes to instant T9, and includes periods P1 through P8, as shown in the figure. The various packets discussed below are also shown in FIG. 1K , placed at their respective times of occurrence. An access point station in a wireless cell signals the beginning of an intra-cell contention-free period for member stations in its cell by transmitting a beacon packet. FIG. 1A shows access point 152 of cell 150 connected to backbone network 160 , transmitting the beacon packet 124 . In accordance with the invention, the beacon packet 124 includes two contention-free period values, the first is the Network Allocation Vector (NAV) (or alternately its incremental value ΔNAV), which specifies a period value P3 for the intra-cell contention-free period for member stations in its own cell. Member stations within the cell 150 must wait for the period P3 before beginning the Tiered Contention Multiple Access (TCMA) procedure, as shown in FIG. 1K . The other contention-free period value included in the beacon packet 124 is the Inter-BSS Network Allocation Vector (IBNAV), which specifies the contention-free time response (CFTR) period P4. The contention-free time response (CFTR) period P4 gives notice to any other cell receiving the beacon packet, such as cell 100 , that the first cell 150 has seized the medium for the period of time represented by the value P4.
[0072] The beacon packet 124 is received by the member stations 154 A (with a low QoS requirement 164 A) and 154 B (with a high QoS requirement 164 B) in the cell 150 during the period from T1 to T2. The member stations 154 A and 154 B store the value of ΔNAV=P3 and begin counting down that value during the contention free period of the cell 150 . The duration of the intra-cell contention-free period ANAV=P3 is deterministically set. The member stations in the cell store the intra-cell contention-free period value P3 as the Network Allocation Vector (NAV). Each member station in the cell 150 decrements the value of the NAV in a manner similar to other backoff time values, during which it will delay accessing the medium. FIG. 1L shows the IEEE 802.11 packet structure 260 for the beacon packet 124 or 120 , including the increment to the NAV period and the CFTR period. The beacon packet structure 260 includes fields 261 to 267 . Field 267 specifies the ANAV value of P3 and the CFTR value of P4. In accordance with the invention, the method assigns to the first access point station, a first inter-cell contention-free period value, which gives notice to any other cell receiving the beacon packet, that the first cell has seized the medium for the period of time represented by the value. The inter-cell contention-free period value is deterministically set.
[0073] Further in accordance with the invention, any station receiving the beacon packet 124 immediately rebroadcasts a contention-free time response (CFTR) packet 126 containing a copy of the first inter-cell contention-free period value P4. The value P4 specifies the Inter-BSS Network Allocation Vector (IBNAV), i.e., the contention-free time response (CFTR) period that the second access point 102 must wait, while the first cell 150 has seized the medium. FIG. 1B shows overlap station 106 in the region of overlap 170 transmitting the CFTR packet 126 to stations in both cells 100 and 150 during the period front T1 to T2. FIG. 1M shows the IEEE 802.11 packet structure 360 for a CFTR packet 126 or 122 , including the CFTR period. The CFTR packet structure 360 includes fields 361 to 367 . Field 367 specifies the CFTR value of P4. In this manner, the notice is distributed to the second access point station 102 in the overlapping, second cell 100 .
[0074] FIG. 1C shows the point coordinator in access point 152 of cell 150 controlling the contention-free period within the cell 150 by using the polling packet 128 during the period from T2 to T3. In the mean time, the second access point 102 in the second cell 100 connected to backbone network 110 , stores the first inter-cell contention-free period value P4 received in the CFTR packet 126 , which it stores as the Inter-BSS Network Allocation Vector (IBNAV). The second access point 102 decrements the value of IBNAV in a manner similar to other backoff time values, during which it will delay accessing the medium.
[0075] Still further in accordance with the invention, the method uses the Tiered Contention Multiple Access (TCMA) protocol to assign to first member stations in the first cell 150 , a first shorter backoff value for high Quality of Service (QoS) data and a first longer backoff value for lower QoS data. FIG. 1D shows the station 154 B in the cell 150 , having a high QoS requirement 164 B, decreasing its High QoS backoff period to zero and beginning TCMA contention to transmit its high QoS data packet 130 during the period from T3 to T4. The backoff time is the interval that a member station waits after the expiration of the contention-free period P3, before the member station 154 B contends for access to the medium. Since more than one member station in a cell may be competing for access, the actual backoff time for a particular station can be selected as one of several possible values. In one embodiment, the actual backoff time for each particular station is deterministically set, so as to reduce the length of idle periods. In another embodiment, the actual backoff time for each particular station is randomly drawn from a range of possible values between a minimum delay interval to a maximum delay interval. The range of possible backoff time values is a contention window. The backoff values assigned to a cell may be in the form of a specified contention window. High QoS data is typically isochronous data such as streaming video or audio data that must arrive at its destination at regular intervals. Low QoS data is typically file transfer data and email, which can be delayed in its delivery and yet still be acceptable. The Tiered Contention Multiple Access (TCMA) protocol coordinates the transmission of packets within a cell, so as to give preference to high QoS data over low QoS data, to insure that the required quality of service is maintained for each type of data.
[0076] The method similarly assigns to the second access point 102 station in the second wireless LAN cell 100 that overlaps the first sell 150 , a second contention-free period value CFTR=P7 longer than the first contention-free period value CFTR=P4. FIG. 1E shows the second access point 102 in the cell 100 transmitting its beacon packet 120 including its contention-free period values of NAV (P6) and IBNAV (P7), to the member stations 104 A (with a low QoS requirement 114 A), 104 B (with a high QoS requirement 114 B) and 106 in the cell 100 during the period from T4 to T5. FIG. 1F shows that each station, including the overlap station 106 , that receives the second beacon packet 120 , immediately responds by retransmitting a second contention-free time response (CFTR) packet 122 that contains a copy of the second inter-cell contention-free period value P7 during the period from T4 to T5.
[0077] FIG. 1G shows the point coordinator in access point 102 of cell 100 controlling the contention-free period within cell 100 using the polling packet 132 during the period from T5 to T6.
[0078] The method uses the Tiered Contention Multiple Access (TCMA) protocol to assign to second member stations in the second cell 100 , a second shorter backoff value for high QoS data and a second longer backoff value for lower QoS data. FIG. 1H shows the station 104 B in the cell 100 , having a high QoS requirement 114 B, decreasing its High QoS backoff period to zero and beginning TCMA contention to transmit its high QoS data packet 134 during the period from T6 to T7. FIG. 1I shows the first member stations 154 A and 154 B in the first cell 150 waiting for the countdown of their NAVs, to begin the TCMA protocol of counting down the first longer backoff for low QoS data and then transmitting first low QoS data 136 during the period from T7 to T8. FIG. 1J shows the second member stations 104 A, 104 B, and 106 are waiting for the TCMA protocol of counting down the second longer backoff for lower QoS data before transmitting the second lower QoS data 138 during the period from T8 to T9.
[0079] The first and second cells are considered to be overlapped when one or more stations in the first cell can inadvertently receive packets from member stations or the access point of the other cell. The invention reduces the interference between the overlapped cells by coordinating the timing of their respective transmissions, while maintaining the TCMA protocol's preference for the transmission of high QoS data over low QoS data in each respective cell.
[0080] During the operation of two overlapped cells, the method in FIG. 1A transmits a first beacon packet 124 including the intra-cell contention-free period value (the increment to the NAV) and inter-cell contention-free period value (the CFTR), from the first access point 152 to the first member stations 154 B and 154 A in the first cell 150 . The beacon packet is received by the member stations of the first cell and inadvertently by at least one overlapped member station 106 of the second cell 100 . Each member station 154 B and 154 A in the first cell increments its NAV with the intra-cell contention-free period value P3 and stores the inter-cell contention-free period value P4 as the CFTR.
[0081] In accordance with the invention, each station that receives the first beacon packet 124 , immediately responds by transmitting a first contention-free time response (CFTR packet 126 in FIG. 1B that contains a copy of the inter-cell contention-free period P4 value (CFTR). A CFTR packet 126 is transmitted from the first member stations 154 B and 154 A in the first cell 150 and also by the overlapped member stations 106 of the second cell 100 . The effect of the transmission of CFTR packets 126 from member stations 106 in the second cell 100 is to alert the second access point 102 and the second member stations 104 A and 104 B in the second cell 100 , that the medium has been seized by the first access point 152 in the first cell 150 . When the second access point 102 in the second cell 100 receives the CFTR packet 126 it stores a copy of the inter-cell contention-free period value P4 as the IBNAV.
[0082] Similar to a station's Network Allocation Vector (NAV), an IBNAV is set at the access point to indicate the time the medium will be free again. Also similar to the NAV, the IBNAV is decremented with each succeeding slot, similar to the decrementing of other backoff times. When the second access point receives a new IBNAV representing the first cell's contention-free period value, then the second access point must respect the IBNAV value and delay transmitting its beacon packet and the exchange of other packets in the second cell until the expiration of the received, IBNAV.
[0083] Later, as shown in FIG. 1E , when the second access point 102 transmits its second beacon packet 120 including its second contention-free period values of NAV (P6) and IBNAV (P7), to the second member stations 104 A, 104 B and 106 in the second cell 100 , each station that receives the second beacon packet, immediately responds by transmitting a second contention-free time response (CFTR) packet 122 in FIG. 1F , that contains a copy of the second inter-cell contention-free period value P7. A CFTR packet 122 is transmitted from the second member stations 104 A, 104 B and overlapped station 106 in the second cell and also by the overlapped member stations of the first cell. The effect of the transmission of CFTR packets from overlapped member station 106 is to alert the first access point 152 and the first member stations 145 A and 154 B in the first cell 150 , that the medium has been seized by the second access point 102 in the second cell 100 . When the first access point 152 in the first cell 150 receives the CFTR packet 122 it stores the a copy of the second inter-cell contention-free period value P7 as an IBNAV, to indicate the time the medium will be free again. The IBNAV is decremented with each succeeding slot, similar to the decrementing of other backoff times.
[0084] The second member stations 104 A, 104 B, and 106 in the second cell 100 wait for completion of the countdown of their NAVs to begin the TCMA protocol of counting down the second shorter backoff for high QoS data and then transmitting second high QoS data packets, as shown in FIGS. 1G and 1H .
[0085] Meanwhile, the first access point 152 in the first cell 150 waits for completion of the countdown of the second inter-cell contention-free period P7 in its IBNAV in FIGS. 1G and 1H before starting the countdown of its own NAV for its own intra-cell contention-free period. The first member stations 154 A and 154 B in the first cell 150 wait for the countdown of their NAVs, to begin the TCMA protocol of counting down the first longer backoff for low QoS data and then transmitting first low QoS data in FIG. 1I .
[0086] Meanwhile the second member stations 104 A, 104 B, and 106 are waiting for the TCMA protocol of counting down the second longer backoff for lower QoS data before transmitting the second lower QoS data 138 in FIG. 1J .
[0087] In this manner, interference in a medium between overlapping wireless LAN cells is reduced.
DETAILED DESCRIPTION OF THE INVENTION
[0088] TCMA can accommodate co-existing Extended Distributed Coordination Function (E-DCF) and centralized access protocols. In order to ensure that the centralized access protocol operating under Hybrid Coordination Function (HCF) is assigned top priority access, it must have the shortest arbitration time. Its arbitration time is determined by considering two additional requirements: uninterrupted control of the channel for the duration of the contention-free period, and backward compatibility.
Uninterrupted Contention-Free Channel Control
[0089] The channel must remain under the control of the centralized access protocol until the contention-free period is complete once it has been seized by the centralized access protocol. For this, it is sufficient that the maximum spacing between consecutive transmissions exchanged in the centralized access protocol, referred to as the central coordination time (CCT), be shorter than the time the channel must be idle before a station attempts a contention-based transmission following the end of a busy-channel time interval. The centralized access protocol has a CCT equal to the Priority Interframe Space (PIFS). Hence, no station may access the channel by contention, using either the distributed coordination function (DCF) or Extended-DCF (E-DCF) access procedure, before an idle period of length of the DCF Interframe Space (DIFS) equaling PIFS+1(slot time) following the end of a busy-channel time interval. This requirement is met by DCF. For E-DCF, it would be sufficient for the Urgency Arbitration Time (UAT) of a class j, UAT j , to be greater than PIFS for all classes j>1.
Backward Compatibility
[0090] Backward compatibility relates to the priority treatment of traffic handled by enhanced stations (ESTAs) as compared to legacy stations (STAs). In addition to traffic class differentiation, the ESTAs must provide certain traffic classes with higher or equal priority access than that provided by the STAs. That means that certain traffic classes should be assigned a shorter arbitration times than DIFS, the de facto arbitration time of legacy stations.
[0091] Because the time in which the “clear channel assessment” (CCA) function can be completed is set at the minimum attainable for the IEEE 802.11 physical layer (PHY) specification, the arbitration times of any two classes of different priority would have to be separated by at least one “time slot”. This requirement implies that the highest priority traffic class would be required to have an arbitration time equal to DIFS-1(slot time)=PIFS.
[0092] Though an arbitration time of PIFS appears to fail meeting the requirement for uninterrupted control of the channel during the contention-free period, it is possible for an ESTA to access the channel by E-DCF using an arbitration time of PIFS and, of the same time, allow priority access to the centralized access protocol at PIFS. This is achieved as follows. Contention-based transmission is restricted to occur after a DIFS idle period following the end of a busy channel period by ensuring that the backoff value of such stations is drawn from a random distribution with lower bound that is at least 1. Given that all backlogged stations resume backoff countdown after a busy-channel interval with a residual backoff of at least 1, an ESTA will attempt transmission following completion of the busy interval only after an idle period equal to PIFS+1(slot time)=DIFS. This enables the centralized access protocol to maintain control of the channel without colliding with contention-based transmissions by ESTAs attempting to access the channel using E-DCF.
[0093] To see that the residual backoff value of a backlogged station will be greater than or equal to 1 whenever countdown is resumed at the end of a busy channel period, consider a station with a backoff value m>0. The station will decrease its residual backoff value by 1 following each time slot during which the channel remains idle. If m reaches 0 before countdown is interrupted by a transmission, the station will attempt transmission. The transmission will either fail, leading to a new backoff being drawn, or succeed. Therefore, countdown will be resumed after the busy-channel period ends, only with a residual backoff of 1 or greater. Consequently, if the smallest random backoff that can be drawn is 1 or greater, an ESTA will always wait for at least a DIFS idle interval following a busy period before it attempts transmission.
[0094] Only one class can be derived with priority above legacy through differentiation by arbitration time alone, by using the arbitration time of PIFS. Multiple classes with that priority can be obtained by differentiation through other parameters, such as the parameters of the backoff time distribution; e.g. the contention window size. For all the classes so derived, a DIFS idle period will follow a busy channel interval before the ESTA seizes the channel if the restriction is imposed that the backoff value of such stations be drawn from a random distribution with lower bound of at least 1.
[0095] Because PIFS is shorter than DIFS, the traffic classes with arbitration time equal to PIFS will have higher access priority than the traffic classes with arbitration time equal to DIFS. As seen in FIG. 1 , which depicts the tiered contention mechanism, a station cannot engage in backoff countdown until the completion of an idle period of length equal to its arbitration time. Therefore, a legacy station will be unable to resume backoff countdown at the end of a busy-channel interval, if an ESTA with arbitration time of PIFS has a residual backoff of 1. Moreover, a legacy station will be unable to transmit until all higher-priority ESTAs with residual backoff of 1 have transmitted. Only legacy stations that draw a backoff value of 0 will transmit after a DIFS idle period, thus competing for the channel with the higher priority stations. This occurs only with a probability less than 3 percent, since the probability of drawing a random backoff of 0 from the range [0, 31] is equal to 1/32.
Top Priority for the Centralized Access Protocol
[0096] For the centralized access protocol to enjoy the highest priority access, it must have an arbitration time shorter than PIFS by at least a time slot; that is, its arbitration time must equal PIFS-1(slot time)=the Short Interframe Space (SIFS). As in the case of the highest traffic priority classes for ESTAs accessing the channel by E-DCF, the random backoff values for the beacon of the centralized access protocol must be drawn from a range with a lower bound of at least 1. Using the same reasoning as above, the centralized access protocol will not transmit before an idle period less than PIFS=SIFS+1(slot time), thus respecting the inter-frame spacing requirement for a SIFS idle period within frame exchange sequences. Consequently, the shorter arbitration time assigned to the centralized access protocol ensures that it accesses the channel with higher priority than any station attempting, contention-based access through E-DCF, while at the same time respecting the SITS spacing requirement.
[0097] It should be noted that while collisions are prevented between frame exchanges during the contention-free period, collisions are possible both between the beacons of centralized access protocols of different BSSs located within interfering range [having coverage overlap], and between the beacon of a centralized access protocol and stations accessing the channel by contention using E-DCF. The probability of such collisions is low because higher priority nodes with residual backoff value m equal to I always seize the channel before lower priority nodes. Inter-access point collisions are resolved through the backoff procedure of TCMA.
Inter-Access Point Contention
[0098] Potential collisions between BSSs engaged in centralized access can be averted or resolved by a backoff procedure. The complication arising here is that a random backoff delay could result in idle periods longer periods than the SIFS+1(slot time)=PIFS, which is what ensures priority access to the centralized protocol over E-DCF traffic contention-based traffic. Hence, the collisions with contention-based traffic would occur. Using short backoff windows in order to avoid this problem would increase the collisions experienced. In accordance with the invention, deterministically set backoff delays are used, which tend to reduce the length of the idle periods.
[0099] Another aspect of inter-BSS interference that affects the performance of centralized protocols adversely is the possible interruption with a collision of what starts as an interference-free poll/response exchange between the access point and its associated stations. The possibility of coincident or overlapping contention-free periods between neighboring BSSs is eliminated through the use of an “interference sensing” method employing a new frame.
Deterministic Backoff Procedure for the Centralized Access Protocol
[0100] A modified backoff procedure is pursued for the beacons of the centralized access protocols. A backoff counter is employed in the same way as in TCMA. But while the backoff delay in TCMA is selected randomly from a contention window, in the case of the centralized access protocol beacons, the backoff value is set deterministically.
[0101] Scheduling of packet transmission occurs once per frame, at the beginning of the frame. Only the packets queued at the start of a frame will be transmitted in that frame. It is assumed that BSSs are synchronized. A means for achieving such synchronization is through the exchange of messages relayed by boundary stations [stations in the overlapping regions of neighboring BSSs].
[0102] The backoff delay is selected through a mechanism called “tag scheduling”. Tags, which are ordinal labels, are assigned to different BSSs. BSSs that do not interfere with one another may be assigned the same tag, while BSSs with the potential to interfere with one another must receive different tags. For each frame, the tags are ordered in a way that is known a priori. This order represents the sequence in which the BSS with a given tag will access the channel in that frame. The backoff delay increases with the rank of the “tag” that has been assigned to the BSS for the current frame, as tags are permuted to give each group of BSS with the same tag a fair chance at the channel. For instance, a cyclic permutation for three tags, t=1, 2, 3, would give the following ordering: 1, 2, 3 for the first frame, 3, 1, 2 next, and then 2, 3, 1. One could also use other permutation mechanisms that are adaptive to traffic conditions and traffic priorities. The difference in the backoff delays corresponding to two consecutive tags is one time slot. FIG. 2 illustrates the ordering of transmissions from three groups of BSSs.
[0103] A backoff counter is associated with each backoff delay. It is decreased according to the rules of TCMA using the arbitration time of Short Interframe Space (SIFS) as described in the preceding section. That is, once the channel is idle for a time interval equal to SIFS, the backoff counter associated with the centralized protocol of the BSS is decreased by 1 for each slot time the channel is idle. Access attempt occurs when the backoff counter expires. The minimum backoff counter associated with the highest-ranking tag is 1. FIG. 3 illustrates how three interfering BSSs share the same channel for two consecutive frames. The tags assigned in each of the two frames are (1, 2), (2, 3), and (3, 1) for the three BSSs, respectively. The backoff delays for the three tags are 1, 2, and 3 time slots.
[0104] When the channel is seized by the centralized protocol of a BSS, it engages in the polling and transmission functions for a time interval, known as the contention-free period. Once the channel has been successfully accessed that way, protection by the Network Allocation Vector (NAV) prevents interference from contention based traffic originating within that BSS. Avoidance of interference from neighboring BSS is discussed below. A maximum limit is imposed on the reservation length in order to even out the load on the channel from different BSSs and allow sufficient channel time for contention-based traffic.
[0105] It is important to note the advantage of using deterministic backoff delays, versus random. Assuming an efficient (i.e., compact) tag re-use plan, deterministic backoff delays increase the likelihood that a beacon will occur precisely after an idle period of length SIFS+1=PIFS. This will enable the centralized protocol to gain access to the channel, as a higher priority class should, before contention-based traffic can access the channel at DIFS=PIFS+1. Using a random backoff delay instead might impose a longer idle period and hence, give rise to collisions with contention-based traffic. Use of short backoff windows to avoid this problem would be ill advised, since that would result in collision between the various BSS beacons.
[0106] Though the backoff delays are set in a deterministic manner, there are no guarantees that collisions will always be avoided. Unless the duration of the contention-free period is the same for all BSSs, there is the possibility that interfering BSSs will attempt to access the channel at once. In case of such a collision, the backoff procedure starts again with the backoff delay associated with the tag assigned to the BSS, decreased by 1, and can be repeated until expiration of the frame. At the start of a new frame, a new tag is assigned to the BSS according to the pre-specified sequence, and the deferral time interval associated with the new tag is used.
[0107] Collisions are also possible if tag assignments are imperfect (interfering BSSs are assigned the same tag). In the event of such a collision, transmission should be retried with random backoff. In order to deal with either type of collision, resolution occurs by drawing a random delay from a contention window size that increases with the deterministic backoff delay associated with the tag in that frame. Though random backoff is used in this event, starting with deterministic backoff helps reduce contention time.
[0108] In a hybrid scenario, random backoff can be combined with tag scheduling. Instead of using backoff delays linked to the rank of a tag in a frame, the contention window size from which the backoff delay is drawn would increase with decreasing rank. The advantage of such an approach is to relax the restrictions on re-use by allowing the possibility that potentially interfering stations will be assigned the same tag. The disadvantage is that the Inter-BSS Contention Period (IBCP) time needed to eliminate contention by E-DCF traffic increases.
Interference Sensing
[0109] Interference sensing is the mechanism by which the occupancy status of a channel is determined. The access point only needs to know of channel activity in interfering BSSs. The best interference sensing mechanism is one that ensures that the channel is not used simultaneously by potentially interfering users. This involves listening to the channel by both the access point and stations. If the access point atone checks whether the channel is idle, the result does not convey adequate information on the potential for interference at a receiving station, nor does it address the problem of interference caused to others by the transmission, as an access point may not be able to hear transmissions from its neighboring access points, yet there is potential of interference to stations on the boundary of neighboring BSSs. Stations must detect neighboring BSS beacons and forward the information to their associated access point. However, transmission of this information by a station would cause interference within the neighboring BSS.
[0110] In order to enable communication of channel occupancy information to neighboring access points, the invention includes the following mechanism. When a beacon packet is transmitted, and before transmission of any other data or polling packets, all stations hearing the beacon will respond by sending a frame, the contention-free time response (CFTR), that will contain the duration of the contention-free period found in the beacon. An access point in neighboring BSSs, or stations attempting contention-based channel access, that receive this message from a station in the BSS overlapping region are thus alerted that the channel has been seized by a BSS. Similar to a station's Network Allocation Vector (NAV), an Inter-Cell Network Allocation Vector, also referred to herein as an inter-BSS NAV (IBNAV), is set at the access point, accordingly, indicating the time the channel will be free again. Unless the IBNAV is reset, the access point will decrease its backoff value only after the expiration of the IBNAV, according to the backoff countdown rules.
[0111] Alternatively, if beacons are sent at fixed time increments, receipt of the contention-free time response (CFTR) frame would suffice to extend the IBNAV. The alternative would be convenient in order to obviate the need for full decoding of the CFTR frame. It is necessary, however, that the frame type of CFTR be recognizable.
[0112] Contention by E-DCF traffic white various interfering BSSs attempt to initiate their contention-free period can be lessened by adjusting the session length used to update the NAV and IBNAV. The contention-free period length is increased by a period Inter-BSS Contention Period (IBCP) during which the access points only will attempt access of the channel using the backoff procedure, while ESTAs wait for its expiration before attempting transmission. This mechanism can reduce the contention seen by the centralized protocols when employing either type of backoff delay, random or deterministic. With deterministic backoff delays, IBCP is set equal to the longest residual backoff delay possible, which is T(slot time), where T is the number of different tags. Given reasonable re-use of the tags, the channel time devoted to the IBCP would be less with deterministic backoff delays, as compared to the random.
QoS Management
[0113] A QoS-capable centralized protocol will have traffic with different time delay requirements queued in different priority buffers. Delay-sensitive traffic will be sent first, followed by traffic with lower priority. Tag scheduling is used again, but now there are two or more backoff values associated with each tag, a shorter value for the higher priority traffic and longer ones for lower priority. A BSS will transmit its top priority packets first, as described before. Once the top priority traffic has been transmitted, there would be further delay before the BSS would attempt to transmit lower priority traffic in order to give neighboring BSSs a chance to transmit their top priority packets. As long as any of the deferral rime intervals for low-priority traffic is longer than the deferral time intervals for higher priority traffic of any tag, in general all neighboring BSSs would have a chance to transmit all pending top-priority packets before any lower-priority packets are transmitted.
[0114] FIG. 4 illustrates how three interfering BSSs, each with two types of traffic of different priorities, share the same channel in two consecutive frames. As before, the tags assigned in each of the two frames are (1, 2), (2, 3), and (3, 1) for the three BSSs, respectively. The deferral times for the top priority traffic are 1, 2, and 3 time slots for tags 1, 2, and 3, respectively. The deferral times for the higher priority traffic are 4, 5, and 6 time slots for tags 1, 2, and 3, respectively.
Tag Assignments
[0115] A requirement in assigning tags to BSS is that distinct tags must be given to user entities with potential to interfere. This is not a difficult requirement to meet. In the absence of any information, a different tag could be assigned to each user entity. In that case, non-interfering cells will use the channel simultaneously even though they have different tags. Interference sensing will enable reuse of the channel by non-interfering BSSs that have been assigned different tags.
[0116] There are advantages, however, in reducing the number of different tags. For instance, if the interference relationships between user entities are known, it is advantageous to assign the same tag to non-interfering BSS, and thus have a smaller number of tags. The utilization of bandwidth, and hence total throughput, would be greater as shorter deferral time intervals leave more of the frame time available for transmission. Moreover, an efficient (i.e., compact) tag re-use plan will decrease the likelihood of contention between the centralized protocol beacons of interfering BSSs contenting for access and E-DCF traffic. This problem is mitigated by using the IBCP time in the IBNAV, but re-use will reduce the length of this time.
[0117] The assignment of tags to cells can be done without knowledge of the location of the access points and/or the stations. Tag assignment, like channel selection can be to done at the time of installation. And again, like dynamic channel selection, it can be selected by the access point dynamically. RF planning, which processes signal-strength measurements can establish re-use groups and thus reduce the required number of tags. FIG. 5 , which includes FIGS. 5( a ) and 5 ( b ), illustrates the possible re-use of tags. In FIG. 5( a ), the access points are located at ideal spots on a hexagonal grid to achieve a regular tessellating pattern. In FIG. 5( b ), the access points have been placed as convenient and tags are assigned to avoid overlap. Imperfect tag assignments will lead to collisions between the access points, but such collisions can be resolved.
[0118] To recap, arbitration times have been assigned to a centralized access protocol that co-exists with ESTAs accessing the channel through E-DCF. The centralized access protocol has the top priority, while E-DCF can offer traffic classes with priority access both above and below that provided by legacy stations using DCF.
[0119] Table 1 illustrates the parameter specification for K+1 different classes according to the requirements given above. The centralized access protocol is assigned the highest priority classification, and hence the shortest arbitration time. The top k-1 traffic classes for the E-DCF have priority above legacy but below the centralized access protocol; they achieve differentiation through the variation of the contention window size as well as other parameters. E-DCF traffic classes with priority above legacy have a lower bound, rLower, of the distribution from which backoff values are drawn that is equal to 1 or greater. Differentiation for classes with priority below legacy is achieved by increasing arbitration times; the lower bound of the random backoff distribution can be 0.
[0120] BSSs within interfering range of one another compete for the channel through a deterministic backoff procedure employing tag scheduling, which rotates the backoff value for fairness among potentially interfering BSS. Re-use of a tag is permitted in non-interfering BSS. Multiple queues with their own backoff values enable prioritization of different QoS traffic classes.
Contention-Free Bursts
[0121] In accordance with the invention, potential collisions between different BSSs engaged in centralized access can be averted/resolved by deterministic backoff delays, which avoid collisions between access points, and eliminate gaps between consecutive poll/response exchanges between the access point and its associated stations. These are referred to as contention-free bursts (CFBs).
Deterministic Backoff Procedure for the Centralized Access Protocol
[0122] A modified backoff procedure is pursued for the beacons of the centralized access protocols. A backoff counter is employed in the same way as in TCMA. But while the backoff delay in TCMA is selected randomly from a contention window, in the case of the centralized access protocol beacons, the backoff value is set deterministically to a fixed value Bkoff, at the end of its contention-free session. Post-backoff is turned on.
[0123] The backoff counter is decreased according to the rules of TCMA using the arbitration time AIFS=SIFS as described in the preceding section. That is, once the channel is idle for a time interval equal to SIFS, the backoff counter associated with the centralized protocol of the BSS is decreased by 1 for each slot time the channel is idle. Access attempt occurs when the backoff counter expires. An HC will restart its backoff after completing its transmission. The deterministic post-backoff procedure is illustrated in FIG. 6 .
[0124] When the channel is seized by the centralized protocol of a BSS, it engages in the polling and transmission functions for a time interval, known as the contention-free period. Once the channel has been successfully accessed that way, protection by the NAV prevents interference from contention based traffic originating in the BSS. Avoidance of interference from neighboring BSS is discussed below.
Non-Conflicting Contiguous Sequences of CFBs
[0125] As long as the value of Bkoff is greater than or equal to the maximum number of interfering BSS, it is possible for the contention-free periods of a cluster of neighboring/overlapping BSSs to repeat in the same order without a collision between them. CFBs of different BSSs can be made to follow one another in a contiguous sequence, thus maximizing access of the centralized protocol to the channel. This can be seen as follows.
[0126] Given a sequence of successful CFBs initiated by different BSSs, subsequent CFBs will not conflict because the follower's backoff counter always exceeds that of the leader by at least 1. If the previous CFBs were contiguous (that is, if consecutive CFBs were separated by idle gaps of length PIFS, the new CFBs will be also continuous because the follower's backoff delay exceeds that of the leader by exactly 1. Channel access attempts by E-DCF stations require an idle gap of length equal to DIFS or greater. FIG. 7 shows the relationships of repeating sequences of CFBs.
[0127] In order to maintain contiguity, an HC that does not have any traffic to transmit when its backoff expires, it will transmit a short packet—a “peg”—and then engage in post-backoff. This way no gaps of length DIFS+1 are left idle until all HCs have completed one CFB per cycle, and restarted the backoff countdown procedure. E-DCF stations are thus prevented from seizing the channel until each BSS completes at least one CFB per cycle. FIG. 8 illustrates the role of pegging in a sequence of CFBs by three overlapping access points.
[0128] Finally it is shown how such a contiguous sequence can constructed by analyzing how a new access point initiates its first CFB. Every time a new access point is installed, it must find its position in the repeating sequence of CFBs. The new access point listens to the channel for the desired cycle, trying to recognize the sequence. It listens for an “idle” PIFS following a busy channel. When that occurs, or after counting Bkoff time slots, whichever comes first, the new access point starts looking for the first idle longer than PIFS, which signifies the end of the sequence of CFBs. As long as the Bkoff is greater than the number of interfering BSS, there will always be such an idle period. The access point sets its post-backoff delay so that it transmits always right at the end of the CFB sequence. That is if at time t, an idle>PIFS has been detected, the access point's backoff at time t is Bkoff-x(t), where x(t) is the number of idle time slots after PIFS. FIG. 9 illustrates this start-up procedure for a new access point, HC2, given an existing access point, HC 1 .
Interference Sensing
[0129] Interference sensing is the mechanism by which the occupancy status of a channel is determined. The access point only needs to know of channel activity in interfering BSSs. The best interference sensing mechanism is one that ensures that the channel is not used simultaneously by potentially interfering users. This involves listening to the channel, by both the access point and stations. If the access point alone checks whether the channel is idle, the result does not convey adequate information on the potential for interference at a receiving station, nor does it address the problem of interference caused to others by the transmission, as an access point may not be able to hear transmissions from its neighboring access points, yet there is potential of interference to stations on the boundary of neighboring BSS. Stations must detect neighboring BSS beacons and forward the information to their associated access point. However, transmission of this information by a station would cause interference within the neighboring BSS.
[0130] In order to enable communication of channel occupancy information to neighboring access points, the following mechanism is proposed. When a beacon packet is transmitted, and before transmission of any other data or polling packets, all stations not associated with the access point that hear the beacon will respond by sending a frame, the contention-free time response (CFTR), that will contain the duration of the contention-free period found in the beacon. An associated station will transmit the remaining duration of the contention-free period when polled. An access point in neighboring BSSs, or stations attempting contention-based channel access, that receive this message from a station in the BSS overlapping region are thus be alerted that the channel has been seized by a BSS. Similar to a station's NAV, an inter-BSS NAV (IBNAV) will be set at the access point accordingly indicating the time the channel will be free again. Unless the IBNAV is reset, the access point will decrease its backoff value only after the expiration of the IBNAV, according to the backoff countdown rules.
[0131] Alternatively, if beacons are sent at fixed time increments, receipt of the CFTR frame would suffice to extend the IBNAV. The alternative would be convenient in order to obviate the need for full decoding of the CFTR frame. It is necessary, however, that the frame type of CFTR be recognizable.
[0132] Contention by E-DCF traffic while various interfering BSSs attempt to initiate their contention-free period can be lessened by adjusting the session length used to update the NAV and IBNAV. The contention-free period length is increased by a period IBCP (inter-BSS contention period) during which the access points only will attempt access of the channel using the backoff procedure, while ESTAs wait for its expiration before attempting transmission. This mechanism can reduce the contention seen by the centralized protocols when employing either type of backoff delay—random or deterministic.
QoS Management
[0133] A QoS-capable centralized protocol will have traffic with different time delay requirements queued in different priority buffers. Delay-sensitive traffic will be sent first, followed by traffic with lower priority. A BSS will schedule transmissions from separate queues so that the QoS requirements are met. It will transmit its top priority packets first, as described before. Once the top priority traffic has been transmitted, the BSS would attempt to transmit lower priority traffic in the CFBs allotted.
[0134] Three parameters are employed to help manage QoS. The deterministic backoff delay, Bkoff, and the maximum length of a CFB and of a DCF transmission. Since these parameters determine the relative allocation of the channel time between the centralized and distributed protocols, they can be adjusted to reflect the distribution of the traffic load between the two protocols. It must be kept in mind, however, that the same value of Bkoff should be used by all interfering BSSs.
QoS Guarantees
[0135] To enable high priority traffic to be delivered within guaranteed latency limits, a variation of the above method is described. CFBs of an access point are separated into two types, or tiers. The first contains time sensitive data and is sent when the period TXdt expires. The second tier contains time non-sensitive traffic and is sent when the backoff counter expires as a result of the countdown procedure. When all neighboring BSS have a chance to transmit their time sensitive traffic, the channel is available for additional transmissions before needing to transmit time-sensitive traffic again. Lower priority contention-free data can be then transmitted, using a backoff-based procedure.
[0136] Tier II CFBs can be initiated in various methods. Two will be described here. They are: (1) random post-backoff, and (2) deterministic post-backoff. Both methods use the same AIFS used for top-priority EDCF transmissions, in order to avoid conflict with Tier I CFBs (i.e. an AIFS=PIFS). Conflict with top priority EDCF transmissions can be mitigated in case (1) or prevented in case (2) through the use of the IBNAV with an IBCP.
[0137] Random post-backoff assigns an access point a backoff drawn from a prespecified contention window. A short contention window would lead to conflicts between Tier II CFBs. A long contention window reduces the conflict between interfering BSS attempting to access the channel at once. Long backoff values would reduce the fraction of the time the channel carries CFBs. Furthermore, the gaps created by multiple consecutive idle slots make room for DCF transmissions, reducing further the channel time available to CFBs. A long IBCP value would alleviate some of the conflict with DCF transmissions.
[0138] Deterministic post-backoff eliminates the problems present with random post-backoff. Conflicts with top priority EDCF transmissions can be prevented with an IBCP of 1. Moreover, as explained above, the Tier II CFBs generated by this method, do not conflict with one another and form contiguous repeating sequences.
Non-Conflicting Contiguous Sequences of Tier I CFBs
[0139] Periodic transmission is achieved by maintaining a timer which is reset at the desired period TXdt as soon as the timer expires. A CFB is initiated upon expiration of the timer. As long as Tier I contention-free periods are all made the same size (by adding time non-critical traffic), which is not less than the maximum DCF transmission or Tier II CFB length, it is possible for the contention-free periods of a cluster of neighboring/overlapping BSSs to repeat in the same order without a collision between them. CFBs of different BSSs can be made to follow one another in a contiguous sequence, thus maximizing access of the centralized protocol to the channel. This can be seen as follows.
[0140] Given a sequence of successful CFBs initiated by different BSSs, subsequent CFBs will not conflict because their timers will expire at least TICFBLength apart. If the leading access point's timer expires while the channel is busy, it will be able to start a new CFB before the follower HC because DCF transmissions are of equal or shorter length, and Type II CFBs have equal or shorter length.
[0141] If the previous CFBs were contiguous (that is, if consecutive CFBs were separated by idle gaps of length PIFS), the new CFBs will be also continuous because the follower's timer will expire on or before the completion of the leader's CFB because their CFBs have the same length. Channel access attempts by E-DCF stations or Tier II CFBs require an idle gap of length equal to DIPS or greater, and hence they cannot be interjected. FIG. 10 shows the relationship of repeating sequences of Tier I CFBs.
[0142] Finally it is shown how such a contiguous sequence can constructed by analyzing how a new access point initiates its first Tier I CFB. Every time a new access point is installed, it musts find its position in the repeating sequence of CFBs. The new access point listens to the channel for the desired cycle, trying to recognize the sequence. It listens for an “idle” PIFS following a busy channel. When that occurs, or after a period TXdt, whichever comes first, the new access, point starts looking for the first idle longer than PIFS, which signifies the end of the sequence of Tier I CFBs. As long as the TXdt is greater than the number of interfering BSS times the duration of a Tier I CFB, TICFBLength, there will always be such an idle period. The access point sets its timer so that it transmits always right at the end of the CFB sequence. That is, if at time t, an idle of length X(t)>PIFS has been detected, the access point's timer at time t is TXdt−X(t)+PIFS. FIG. 11 illustrates this start-up procedure for a new access point, HC2, given an existing access point, HC1.
Possibility of Collisions
[0143] Though the backoff delays are set in a deterministic manner, there are no guarantees that collisions will always be avoided. Unless all access points sense the start and end of CFBs at the same time, there is the possibility that interfering BSSs will attempt to access the channel at once. This situation arises when there is significant distance between access points, but not sufficient to eliminate interference between them. Such a situation can be alleviated through the assignment for different channels.
[0144] Arbitration times are assigned to a centralized access protocol that co-exists with ESTAs accessing the channel through E-DCF. The centralized access protocol has the top priority, while E-DCF can offer traffic classes with priority access both above and below that provided by legacy stations using DCF.
[0145] Table 1 illustrates the parameter specification for K+1 different classes according to the requirements given above. The centralized access protocol is assigned the highest priority classification, and hence the shortest arbitration time The top k-1 traffic classes for the E-DCF have priority above legacy but below the centralized access protocol; they achieve differentiation through the variation of the contention window size as well as other parameters. E-DCF traffic classes with priority above legacy have a lower bound, rLower, of the distribution from which backoff values are drawn that is equal to 1 or greater. Differentiation for classes with priority below legacy is achieved by increasing arbitration times; the lower bound of the random backoff distribution can be 0.
[0000]
TABLE 1
TCMA Priority Class Description
Priority
Description
Arbitration time
rLower
0
Centralized access protocol
SIFS
>=1
I to k-I
E-DCF Traffic with priority
PIFS = SIFS +
>=1
Legacy or Centralized access
1 (slot time)
Tier II CFBs
k
E-DCF Legacy-equivalent
DIFS = SIFS +
0
traffic priority
2 (slot time)
N = k +
E-DCF Traffic priority below
>DIFS = SIFS +
0
I to K
Legacy
(2 + n − k) (slot time)
[0146] BSSs within short interfering range of one another can compete for and share the channel through the use of a deterministic backoff procedure employing post-backoff. Contiguous repeating sequences of contention-free periods provide the centralized protocol efficient access to the channel which is shared by E-DCF transmissions. The relative channel time allotted to the two protocols can be adjusted by tuning parameters of the protocol. Scheduling of traffic queued in multiple queues at the access point can meet QoS requirements. More stringent latency requirements can be met with a two-tiered method, which employs both a timer and post-backoff to initiate CFBs.
[0147] CFB contiguity is preserved when using deterministic post-backoff or if CFBs of constant length are used whenever transmission is caused by the expiration of the TXdt timer-the Tier I approach. Contiguity is not necessarily preserved, however, if the CFBs have variable length when the Tier I approach is used. Any gaps that would arise in this case would allow contention-based transmissions to be interjected, thus risking delays and possible collisions between HCs.
[0148] Because of the fixed CFB length requirement, whereas the Tier I approach delivers regularly-spaced CFBs, using it alone, without a Tier II protocol, results in inefficient utilization of the channel. The same fixed bandwidth allocation to each BSS gives rise to situations where channel time allocated for a CFB to one BSS may be left idle while another BSS is overloaded. The Tier II protocols provide for dynamic bandwidth allocation among BSSs.
[0149] Various illustrative examples of the invention have been described in detail. In addition, however, many modifications and changes can be made to these examples without departing from the nature and spirit of the invention. | A method and system reduce interference between overlapping first and second wireless LAN cells in a medium. Each cell includes a respective plurality of member stations and there is at least one overlapped station occupying both cells. An inter-cell contention-free period value is assigned to a first access point station in the first cell, associated with an accessing order in the medium for member stations in the first and second cells. The access point transmits a beacon packet containing the inter-cell contention-free period value, which is intercepted at the overlapped station. The overlapped station forwards the inter-cell contention-free period value to member stations in the second cell. A second access point in the second cell can then delay transmissions by member stations in the second cell until after the inter-cell contention-free period expires. | 7 |
BACKGROUND OF THE INVENTION
[0001] The present invention relates to a fuel cell device, and also to a method of operating the fuel cell device.
[0002] Modern fuel cell systems both for stationary and for mobile applications are generally operated so that the anode side is supplied with fuel, in particular hydrogen, and the cathode side is supplied with oxygen, in particular air. The supplied and the withdrawn gas streams are pumped or blown in and out of the fuel cell stack. This means that the current fuel cell stacks operate in a through flow or the operating material streams flow through them.
[0003] Partially, on the anode side of the stack a relatively high quantity of not converted hydrogen is blown off. Partially, the hydrogen containing anode waste gas is pumped or recycled in a circle, to improve the total efficiency of the system.
[0004] Furthermore, conventionally at least the cathode gas is moisturized before the entry in the fuel cell stack, in order not to dry the protons-guiding membrane of the stack. Corresponding membranes or MEAs (Membrane Electrode Assembly) must have a certain average moisture, to conduct the protons. Along the flow path of the cathode gas, water is produced which is partially taken by the cathode gas. Partially, so much water can be produced on the membrane, that water stays on the membrane and thereby the contact of the hydrogen protons passing through the membrane with the oxygen molecules of the cathode gas no longer can be completely guaranteed.
[0005] The above described as well as other effects lead for example to local drying and wetting of the membrane, depletion of the operation gas, temperature changes, wherein also temperature influences act on conductivity of the membrane, so that during the through flow of the stack high inhomogenuities occur with respect to the gas composition, stack and gas temperature, membrane and gas moisture, as well as the pressure. This inhomogenuities reduce the efficiency of the fuel cell system.
SUMMARY OF THE INVENTION
[0006] Accordingly, it is an object of the present invention to provide a fuel cell device, which avoids the disadvantages of the prior art.
[0007] More particularly, it is an object of the present invention to provide a fuel cell device with a fuel cell unit and a control unit for controlling and/or regulation of at least one adjusting element, wherein the adjusting element is formed for influencing at least one operational substance (fuel) stream of the fuel cell unit, and also to provide a method of operating a fuel cell device, wherein inhomogenuities of the fuel cell unit or the membrane are significantly reduced.
[0008] In keeping with these objects and with others which will become apparent hereinafter, one feature of the present invention resides, briefly stated, in a fuel cell device, comprising a fuel cell unit; at least one adjusting element for influencing at least one fuel stream of said fuel cell unit; a control unit for controlling and/regulating of at least one adjusting element, said control unit being formed so that at least in one operational mode it provides a periodic filling and emptying of said fuel cell unit.
[0009] Another feature of the present invention resides, briefly stated, in a method of operating a fuel cell device, comprising the steps of flowing a fuel stream into a fuel cell unit; flowing at least partially converted fuel stream out of the fuel cell unit; and providing at least one filling phase for filling the fuel stream and emptying phase, which substantially follows in time, for emptying at least partially converted fuel stream.
[0010] The fuel cell device in accordance with the present invention, in addition to other structural elements, is formed so that at least in one operating mode the control unit is formed for periodic filling and emptying of the fuel cell unit.
[0011] The method in accordance with the present invention, in addition to other method features, is performed so that at least one filling phase for filling the fuel stream and one substantially subsequent emptying phase for emptying the at least partially converted fuel stream are provided.
[0012] With the present invention, in particular the operation of the fuel cell device is realized in a cycled fashion or in a charge fashion. In contrast to the prior art, in which due to the throughflow operation almost always local inhomogenuities are produced or reinforced, the corresponding inhomogenuities in the present invention, due to filling and the emptying of the fuel cell element or due to the filling phase and the emptying phase, are destroyed or can not develop to a degree as in the prior art. Thereby, the membrane can be relatively uniformly moisturized and tampered.
[0013] Moreover, a depletion of the relevant gas components, in particular of hydrogen and oxygen, in the fuel cell is substantially prevented. Correspondingly, the efficiency of the fuel cell system when compared with the prior art is significantly increased and the loading of the fuel cell stack or the membrane is significantly reduced, which is exhibited in a higher service life of the stack.
[0014] The periodic filling or emptying of the fuel cell unit or the fuel cell stack can be realized by a change of the cathode and/or anode volume. For example it is recommended that the fuel cell stack can be formed in the form of a bellows or the same, wherein periodic filling or emptying is realized by corresponding volume changes.
[0015] Preferably, the control unit is formed for changing a pressure of the fuel stream. By means of a correspondingly formed control unit, the filling or emptying is realized by a pressure increase or a pressure reduction. Correspondingly, expensive constructions for changing the volume of the corresponding fuel cell units are dispensed with and/or commercially available components can be used with small structural changes, which ensures an especially efficient realization of the invention.
[0016] A pressure-loaded storage can be provided in accordance with the present invention for storing the fuel stream. By means of an adjusting element, such as for example a regulating valve or the like, the pressure change of the fuel stream can be converted for the periodic filling or emptying of the fuel cell unit.
[0017] Alternatively, or in combination with it, at least one pressure generating unit can be provided for generation of the pressure change of the fuel stream. The pressure generating unit can be formed for example as a blower, fan and/or condensor so that by controlling or regulating the pressure generating unit by means of the control unit, an advantageous adaptation of the fuel pressure can be provided.
[0018] In accordance with a special further embodiment of the present invention, in the region of the proton conducting membrane of the fuel cell unit, at least one direction change is provided between a filling direction of the fuel stream and an emptying direction of the at least partially converted fuel stream. It is possible that the filling direction is substantially opposite to the emptying direction. With this feature it is guaranteed that at least a partial region of the fuel stream flows preferably twice or many times over. Thereby in advantageous manner, inhomogenuities with respect to the gas composition, stack and gas temperature, membrane and gas moisture as well as the pressure are substantially compensated. Therefore, an especially efficient reduction of the inhomogenuities and an especially advantageous increase of the efficiency of the fuel cell system are provided.
[0019] In some cases, for example depending on the fuel stream, a filling and a separate emptying opening of the fuel cell unit are provided. It is possible that the filling openings and the emptying openings are arranged in the same side of the fuel cell unit or the fuel cell stack. It is recommended to provide several filling openings and/or several emptying openings depending on the fuel stream.
[0020] In a preferable embodiment of the invention, a filling opening of the fuel cell unit corresponds to an emptying opening of the fuel cell unit. Thereby an especially simple, efficient favorable embodiment of the invention can be realized. For example, a closing or an opening element for opening or closing of the corresponding opening is provided. Correspondingly the structural expenses are reduced.
[0021] Advantageously, the fuel stream is formed as an oxidation medium stream, in particular as air stream of a cathode of the fuel cell unit. Frequently, alternatively or in combination with it, the reduction medium stream or hydrogen stream is formed on the anode of the fuel cell unit as a fuel stream in accordance with the invention. Preferably, a filling phase and an emptying phase of the oxidation medium stream, as well the reduction medium stream are substantially realized in the same time or in the same phase. Thereby the substantially pressure-sensitive membrane of the fuel cell unit is loaded substantially uniformly with pressure from both sides, so that a negative effect on the membrane is efficiently prevented.
[0022] In a preferable variant of the invention, the control unit is formed for adaptation of the pressure changes of the fuel stream depending on the power output of the fuel cell unit. With this feature, the fuel cell unit can be advantageously adapted to dynamic load requirements, in particular in mobile or vehicle applications in advantageous manner.
[0023] Preferably, for example an amplitude, a frequency and/or an average value of the amplitude or the pressure changes of the fuel stream, are substantially proportional to the power output of the fuel cell unit. For example a spreading of the amplitude and/or an increase of the average value of the amplitude is provided with an increase of the power output. It is possible that the frequency of the periodic pressure change or the filling and/or emptying phase is adapted proportionally to the power output, wherein an increase of frequency is provided with an increase of the stack output power.
[0024] Preferably, a volume of the cathode of the fuel cell unit is substantially greater than a volume of the anode of the fuel cell unit. For example, the cathode volume is many times or approximately 4 times greater than the anode volume of the fuel cell unit. Thereby in an advantageous manner an air gulping at the cathode side by consumed oxygen is correspondingly weakened or completely prevented. It is possible to provide a post-regulation of the oxygen concentration of the cathode side. Alternatively, or in combination with it, in the anode side, the pressure buildup can take place by hydrogen consumption because of the fuel cell action, which by means of the control unit or at least one pressure buildup regulator can be continuously regulated or post-controlled. Thereby a substantially constant average hydrogen concentration at the anode side is available.
[0025] In general, with the pressure fluctuation of the fuel stream, in particular by partial pressure fluctuation, in the fuel cell unit a change or fluctuation of the stack voltage occurs. This can be taken care of or compensated in an advantageous manner substantially by a corresponding power electronics, in particular by means of a DC/DC convertor.
[0026] Generally, the gasses which flow into the fuel cell can be heated or tampered by one or several heat exchangers in advantageous manner by the outflowing gas or another heating fluid.
[0027] In an advantageous embodiment of the invention, at least one sensor is provided for detecting a partial pressure, in particular of the oxygen and/or the hydrogen. Alternatively, or in combination with it, also the moisture content of an at least one fuel stream can be detected or sensed by means of an advantageous sensor. The control unit in accordance with the present invention controls or regulates corresponding adjusting members such as valves, pressure generating units, fuel storage, etc.
[0028] Basically, corresponding fuel cell devices can be used in so-called APU applications and/or in travel drive systems or in stationary applications.
[0029] Summarizing the above, it should be emphasized that the core of the invention is a filling and emptying of the fuel cell unit, which is substantially similar to breathing of living beings. This leads to the situation, that first of all, by inflow of the cathode gas or outflow of the cathode gas in an opposite direction, contrary to the prior art, it flows many times at least through a partial region of the membrane and thereby takes water formed on the membrane during the filling in, and gives out water from the membrane during emptying, so that both the formation of differently moisturized membrane regions and thereby directly interacting, different temperature distributions of the membrane are efficiently eliminated or reduced. Correspondingly, the efficiency of the fuel cell system is increased.
[0030] The novel features which are considered as characteristic for the present invention are set forth in particular in the appended claims. The invention itself, however, both as to its construction and its method of operation, together with additional objects and advantages thereof, will be best understood from the following description of specific embodiments when read in connection with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
[0031] FIG. 1 is a view schematically showing a block diagram of an inventive fuel cell device; and
[0032] FIG. 2 is a view schematically showing a course of pressure changes in the inventive fuel cell device.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0033] FIG. 1 schematically shows the construction of a fuel cell device in accordance with the present invention. The fuel cell device has a fuel cell 1 with an anode 2 , a cathode 3 and a membrane 4 . An electric power P ei is available on the membrane 4 .
[0034] The fuel cell 1 in the shown embodiment has an opening 5 of the anode 2 and an opening 6 of the cathode 3 , through which air 7 or a hydrogen-containing gas 8 can flow in and flow out. Thereby the fuel cell 1 in accordance with the present invention is periodically filled and emptied.
[0035] For periodically filling and emptying, an oxygen supply 9 and a hydrogen supply 10 have several, in particular controllable or regulatable components.
[0036] For example, the fuel supply 9 of the fuel cell 1 includes a compressor 1 , which for example aspirates atmospheric air from the environment and compresses it to the required operational pressure. For fine adjustment of the oxygen or air pressure of the oxygen supply 9 , a pressure regulating valve 12 can be provided. Furthermore, the oxygen supply 9 includes a pressure drain valve 13 and a pressure measuring element 14 .
[0037] A not shown control unit for control or regulation of the valves 12 , 13 as well as of the compressor 11 opens for example the valve 12 in the filling phase, whereas the pressure drain valve 13 is closed, so that pressure loaded oxygen flows into the cathode 3 . In the emptying phase the pressure regulating valve 12 is partially or completely closed and the pressure drain valve 13 is open, so that the pressure in the cathode 3 is reduced approximately to environment pressure, wherein at least partially converted air flows out of the system.
[0038] Correspondingly, the cathode 3 is filled or emptied, generally in the same phase as the anode 2 with pressure loaded hydrogen 8 . For this purpose the fuel supply 10 has for example a storage 5 , which intermediately stores the hydrogen 8 or hydrogen-containing gas. In some cases the hydrogen is produced on-board in a vehicle by means of a reformer or the like from hydrocarbons, such as gasoline or diesel, etc. In some cases the hydrogen 8 can be stored in a tank directly in liquid or gaseous form.
[0039] The tank 15 filled with the pressure-loaded hydrogen 8 is arranged in a flow direction before the pressure regulating valve 16 . Therefore an advantageous fine regulation of the hydrogen 8 which acts with pressure on the anode 2 can be realized. Correspondingly at the cathode side the filling phase is realized so that the pressure regulating valve 6 and the purge valve 17 is closed. The emptying phase of the anode 2 is thereby converted, so that the valve 16 is closed and the valve 17 is open, and therefore at least partially converted hydrogen 8 can be available for recycling or repeated use via a container 18 and a compressor 19 of the anode in the filling phase. Due to the circulation guidance of the partially converted hydrogen 8 the total efficiency of the system is advantageously increased.
[0040] A pressure measuring element 20 and 14 is connected with the advantageous control unit, not shown in the drawings. It senses the pressure produced on the cathode 3 or on the anode 2 and advantageously controls or regulates the corresponding components of the system. An optionally provided spraying valve 21 is arranged in advantageous manner on the cathode 9 , so that in some cases in a spraying phase the anode 2 is can be sprayed in a through flow. For this purpose some accumulated residual gas or the like is removed without great expenses from the anode 2 . The spraying valve 21 can be connected to the input 5 , so that instead of the through flow a return flow is generated. Thereby the stack structure is generally somewhat simplified. It is possible that the cathode 3 includes a corresponding spraying unit, not shown in the drawings.
[0041] The fuel cell 1 in accordance with the present invention, in contrast to the prior art, is operated most of the time not in a through flow operation, but instead in a periodic filling and emptying operation. For this purpose the outputs available in the prior art in conventional fuel cell units 1 are closed, so that the filling and the emptying can be performed in some cases by means of the same opening 5 or 6 .
[0042] Advantageously, at the anode and the cathode side the pressure is substantially increased in the same phase, which prevents a destruction of the membrane 4 by damaging pressure differences in an efficient way. Subsequently, the pressure buildup ends and in some cases the gasses 7 , 8 are locked in the fuel cell unit 1 during a predetermined time. With the purge valve 17 , the pressure at the anode side is lowered in the hydrogen container 18 , and at the cathode side 3 via an outlet valve 13 the pressure also is lowered, however outwardly into the environment. Subsequently the hydrogen gas 8 is pumped from the container 18 by a compressor or condensor 19 into the stack 1 or into the anode 3 . At the cathode side 3 , the pressure is correspondingly increased by the pressure regulating valve 12 .
[0043] The anode side pressure reduction, due to hydrogen consumption because of the fuel cell operation, is continuously regulated by means of the pressure regulating element 20 and a fuel unit. In some cases with high stack output power, for example the frequency of the periodic modulation or the filling and emptying of the fuel cell unit 1 is increased, and with low stack powers is correspondingly reduced. In some cases alternatively the operation can be performed with particularly slow, variable operational pressure and in some cases with superimposed pressure modulation. The modulation value can be adjusted in some cases to the power output of the stack 1 .
[0044] A corresponding change of the pressure modulation is schematically shown in FIG. 2 . For example in a phase PI the air 7 or the hydrogen 8 fills the fuel cell 1 or is emptied from it with an average pressure of approximately 1.8 bar and an amplitude of approximately 0.6 bar. With a load change from the phase PI to a phase PIII, an intermediate phase PII is provided, so that in the phase PIII for example the average pressure of the modulation is increased to approximately 2.2 bar and an amplitude is available at approximately 1.6 bar. In phase PI the stack 1 provides a lower power to a corresponding consumer that in the phase PII. Correspondingly, the pressure in the phase PI changes modulated as in phase PIII and, as described above, the average pressure level correspondingly changes. Low pressure differences between the anode and the cathode side are tolerable within a certain range provided by the stack construction.
[0045] The pressure course basically can be approximately sine-shaped, as shown for example in FIG. 2 . Alternatively, the pressure course can run however substantially rectangularly or substantially rounded or in another fashion. Generally, the pressure course is provided by the properties or dynamics of the pressure generator and/or the available fuel cell components, which act for example in a corresponding damping of the pressure course.
[0046] It will be understood that each of the elements described above, or two or more together, may also find a useful application in other types of constructions differing from the types described above.
[0047] While the invention has been illustrated and described as embodied in fuel cell device, and method of operating the fuel cell device, it is not intended to be limited to the details shown, since various modifications and structural changes may be made without departing in any way from the spirit of the present invention.
[0048] Without further analysis, the foregoing will so fully reveal the gist of the present invention that others can, by applying current knowledge, readily adapt it for various applications without omitting features that, from the standpoint of prior art, fairly constitute essential characteristics of the generic or specific aspects of this invention. | A fuel cell device has a fuel cell unit, at least one adjusting element for influencing at least one fuel stream of the fuel cell unit, a control unit for controlling and/regulating of at least one adjusting element, the control unit being formed so that at least in one operational mode it provides a periodic filling and emptying of the fuel cell unit. | 7 |
[0001] This application claims priority from Provisional U.S. patent application Ser. No. 60/227,907, filed Aug. 28, 2000 by de la Chica, et al. which is hereby incorporated by reference in its entirety, and to Provisional U.S. patent application Ser. No. 60/276,950, filed Mar. 20, 2001 by de la Chica, et al, which is hereby incorporated by reference in its entirety. This application is also related to U.S. Patent Application entitled “System and Methods for the Production, Distribution, and Flexible Usage of Electronic Content in Heterogeneous Distributed Environments” filed by McCutchen, et al., concurrent with the filing of this application, the teachings of which is hereby incorporated in its entirety.
[0002] This application includes material which is subject to copyright protection. The copyright owner has no objection to the facsimile reproduction by anyone of the patent disclosure, as it appears in the Patent and Trademark Office files or records, but otherwise reserves all copyright rights whatsoever.
FIELD OF THE INVENTION
[0003] The present invention relates to the field of flexible usage of electronic content or electronic data in heterogeneous distributed environments.
BACKGROUND OF THE INVENTION
[0004] With the advent of advanced computer networking infrastructures such as the Internet and its successors, and the ever-increasing penetration of computers and computerized devices in everyday life, traditional manifestations of content—audio, visual, textual, and/or multimedia to name a few—continue to give way to higher quality electronic manifestations of said content. Electronic manifestations of content feature a series of innate properties that make them especially suitable for cheaper production, easier acquisition (including ownership transfers), and enhanced usage.
[0005] In addition to leveraging production pricing differentials brought about by faster, cheaper technology in the fields of central processing unit (CPU) speeds, data storage, and display devices, electronic manifestations of content facilitate searching and manipulation using well-known techniques in the areas of information indexing and electronic signal and symbol manipulation. Lower production costs for electronic manifestations of content have resulted in an increase in the volume of all forms of content available to end-users. In turn, increasing volumes of content have resulted in end-users being faced with a deluge of content that makes flexibility and ease of use key factors for the widespread adoption of electronic forms of content. This electronic content availability explosion has been accompanied by increasing concerns for the protection of the rights of the content creator or copyright owner (collectively “content creator”). The business and legal needs of protecting the rights of the copyright owner to these electronic manifestations of content is at odds with the mass distribution capabilities facilitated by advances in networking technology and applications.
[0006] Research and analysis of existing technology and inventions in the area of electronic content creation, acquisition, manipulation and usage show an increased focus in the following three areas: usage rights expression and enforcement, cryptographic techniques, and dedicated display devices. While the existing state-of-the-art in the aforementioned domains addresses important aspects of those domains, a vacuum exists in the areas that take advantage of the electronic medium to facilitate widespread adoption of electronic manifestations of content requiring secure delivery and controlled fair usage. In addition, existing technology and invention efforts fail to take into account the socio-economic factors accompanying the introduction of any new technology. As a result, the existing electronic content technologies and inventions tend to “get in the way” of content users accomplishing their goals, including attaining competitive advantages, informational enrichment, and entertainment.
[0007] In an information-driven environment, content users find it hard to tolerate the limitations brought about by inventions and products that hinder the content user's ability to locate, acquire, and use content in ways that protect the rights of the content owner while providing the content user with the flexibility previously afforded by earlier content technologies such as print books and magazines; music records, tapes and CDs; and movie DVDs. Current trends often force the end-user to tie the electronic content to a specific device, a tenet contrary to the uber-connectivity facilitated by advances in the communications and networking areas such as the Internet, wireless networks, and virtual private networks (VPNs).
[0008] Some inventions and commercial products exist in the usage rights technology arena that provide coverage in the areas of electronic content usage rights expression and enforcement of said rights descriptions. For example, U.S. Pat. No. 5,715,403, to Stefik, incorporated herein by reference, defines a limited grammar that allows the rights owner to describe a limited set of usage rights, and protocols that allows an entity to request and exercise any approved usage right defined at production time by the rights owner. The proposed limited usage rights grammar focuses on computer-centric atomic operations such as electronic content viewing, copying, and embedding while making no provision for the premise that the content rights owner and end-user may be interested in defining more flexible usage models that go beyond binary responses to requests for simple actions on the electronic content for a particular device.
[0009] Other prior art also attempts to address some of the shortcomings in content usage rights control through various schemes. For example, U.S. Pat. No. 5,845,281, to Benson, et al., which is incorporated herein by reference, addresses issues associated with enforcing usage rights via a computer program that checks content usage control data against content usage requests by an end user, and either grants or denies such access requests. In addition, U.S. Pat. No. 6,182,218, to Saito, incorporated herein by reference, presents both invisible and visible digital watermarking techniques for tracking electronic content usage through the use of a digital content management program embedded in the user's system.
[0010] While the aforementioned copyright protection techniques may prove useful in simple circumstances, these inventions do not address issues brought about by the fact that most end-users own a variety of rendering devices and systems. In addition, grammars proposed in the prior art fail to address a user's desire to engage in independent electronic content trading and exchange. This is an important oversight, as such trading and exchange may take place after a user has legally acquired a protected electronic content item.
[0011] Moreover, such inventions fail to recognize the need to provide content usage boundaries that adequately reflect and account for the environment surrounding content users where flexibility and ease of use are prime objectives. In other words, the state of the art fails to strike a balance between the content creator's copyright and piracy protection desires and the content user's yearning for flexibility and ease of electronic content use across multiple rendering devices and systems.
[0012] The field of cryptography finds its roots in ancient practices aimed to disguise, protect and securely transfer personal, political and military messages. Kahn provides in depth non-technical coverage of the history of cryptography from Ancient Times until the date of writing (1963) in his book The Codebreakers, which is incorporated herein by reference. Additional in-depth technical descriptions can be obtained from reading the Handbook of Applied Cryptography by Menezes, et al, incorporated herein by reference. In recent years, advances in the field of public-key cryptography have given rise to the publication of standard system definitions, such as the Public Key Infrastructure (PKI), which aim to formally describe usage of advanced cryptographic techniques initially described by Diffie and Hellman in their article “New directions in cryptography” in IEEE Transactions on Information Theory 22 (1976), the teachings of which are incorporated herein by reference. U.S. Pat. No. 6,098,056, to Rusnar and Zeintara, describes a three-level PKI-based approach solution for the cryptographic problem of trusted delivery of electronic content and its decryption. U.S. Pat. No. 6,226,618, Downs et al., provides a variation of the three-level PKI-based electronic content decryption key transfer where the intermediary is a “trusted” clearinghouse. U.S. Pat. No. 6,237,786, Van Wie and Weber, describes techniques that allow the invisible and indelible transfer of electronic rights management control information within a signal being transferred via an insecure channel. The teachings of the aforementioned patents are included herein by reference.
[0013] As illustrated by the aforementioned cryptography-related patents and references, current state of the art focuses on improved methods for content encryption and decryption key transfer while largely ignoring many of the issues associated with the practical usage of the electronic content once securely delivered to the end user.
[0014] New advances in electronics and electronic components have provided an environment where new inventions and products are conceived either as dedicated or multi-purpose electronic content rendering devices, including music devices and electronic book devices. U.S. Pat. No. 5,636,276, to Brugger, proposes a device for the secure, encrypted distribution of music in electronic form. U.S. Pat. No. 5,956,034, to Sachs and Pomeroy, describes a device capable of providing secure rendering of electronic books using encryption and in-memory decryption techniques. In both cases, the inventions focus mainly on generic protection of the electronic content while in transit as well as during aural or graphical rendering. Also importantly, the aforementioned patents serve to also exemplify the increasing number of content and rendering options available to users. The aforementioned patents are incorporated herein by reference.
[0015] As seen from the provided references, the current state of the art fails to address issues associated with providing users with an experience that is both pleasant and consistent with legally and socially acceptable fair content uses. It is particularly significant to note that none of the aforementioned inventions and products makes any provisions for supporting the availability of multiple content rendering systems and autonomous electronic content markets to the user. Similarly, provisions and mechanisms have not been developed which provide a user with ubiquitous access to electronic content. Such access would enable a user to experience content independent of their physical location or target rendering system.
[0016] For the purposes of describing the invention, the term “rendering system” refers to any combination of hardware and software components used to play back the electronic content visually, aurally, or by any other sensorial means. The separation of content from content rendering systems is important since it more closely describes commonly accepted practices such as playing a music Compact Disc (CD) using a CD player inside a vehicle and later playing the same music CD in a player located inside a house. In addition, the term “autonomous electronic content markets” and “autonomous electronic markets” refer to any combination of hardware and software components used to support legal, user-defined electronic content trade and exchange transactions.
SUMMARY OF THE INVENTION
[0017] Accordingly, the present invention is directed to systems and methods for flexible electronic content usage in heterogeneous distributed environments that substantially obviates one or more of the problems due to limitations and disadvantages of the related art.
[0018] An object of the present invention is to allow extensible personal content management in a distributed heterogeneous environment.
[0019] Another object of the present invention is a system and methods to organize electronic content under personal content management system control into a virtual information portfolio containing one or more logical content groups, wherein a content group may recursively contain zero or more logical content groups.
[0020] An additional object of the present invention is an extension of the personal content management system to encompass both unprotected and protected electronic content. The personal content management system can also be further extended to process unprotected and protected content uploads, as well as electronic order confirmations for protected or unprotected content which originate from disparate electronic content distribution systems.
[0021] A further object of the present invention is to enable users to access personal content management systems from any access point within a distributed networked environment, utilizing tethered or wireless network access means.
[0022] Another object of the present invention is to allow users to fully or partially transfer selected electronic content items currently under personal content management system control to a distributed computing device for rendering and usage while in either network-connected or stand-alone modes.
[0023] An additional object of the invention is to extend the personal content management system to adaptively transform electronic content to match target rendering system capabilities.
[0024] Still another object of the invention is to provide a flexible, autonomous content market that also provides consistent and reliable copyright enforcement. The present invention provides such a content market through a system and methods by which individual electronic content items can be designated as available to either the general public or selected communities. Furthermore, users may designate individual content items as transferable, thereby indicating the content owner's desire to transfer electronic content ownership to a third-party, either temporarily or permanently. In addition, such ownership transfers may involve financial transfers between users or entities, including the involvement of an intermediary.
[0025] Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.
[0026] The present invention can be seen as extending and enhancing the prior art in the fields of electronic content usage rights enforcement and electronic content rendering device definition systems. In addition, the present invention provides methods supporting fair and flexible electronic content usage in distributed network environments. The present invention provides those improvements through systems and methods that enable users to manage and use disparate content in a distributed network environment by using a personal content management system.
[0027] Through a collection of hardware and software components, a personal content management system can track content attributes, such as content location, thereby allowing a user to access and control content stored in disparate locations through a consistent, easy to use interface. The personal content management system can also give users a virtual information portfolio, through which user owned content can be managed and organized. A virtual information portfolio may consist of a combination of hardware and software components which provide users with distributed virtual electronic content repositories. A virtual information portfolio provides users with a variety of electronic content presentations by transparently handling physical electronic content access. A virtual information portfolio provides both automatic and manual content grouping methods. Logical content groups may in turn contain zero or more internal content groups as designated by the user.
[0028] In a preferred embodiment, such content groups may be presented to a user through a tree-like graphical representation. In such a visualization scenario, intermediate nodes in a tree may represent logical groups, and terminal leaves in a tree can represent actual individual content available for upload, download, transformation, playback, exchange, trading and other operations. The preceding preferred embodiment description is intended to be exemplary, and should not be interpreted as limiting the scope of the present invention.
[0029] Since the virtual information portfolio may contain private information, the present invention also provides systems and methods to support user authentication. In a preferred embodiment, users are uniquely identified through PKI certificates. Authenticity of such certificates may be verified using a variety of methods, including, but not limited to, traditional authentication methods, like usernames and passwords, as well as more sophisticated authentication means, such as biometric identification techniques. While PKI provides established techniques to accomplish such authentication, the preceding description of a preferred embodiment is included here as exemplary and should not be considered as limiting the scope of the present invention to solely a PKI based approach.
[0030] The personal content management system leverages a template, or plug-in, architecture to provide an extensible mechanism capable of handling idiosyncrasies associated with specific electronic content upload, download, protection, and rendering systems. Furthermore, the virtual information portfolio provides mechanisms that enable a user to consistently manage protected and unprotected electronic content from a variety of sources. A virtual information portfolio provides access to content metadata that, in a preferred embodiment, can be used to describe and represent content owned by a user. For the purpose of describing the present invention, the term metadata refers to ancillary information about an electronic content item, and may include author, title, publication date, publisher name, and other information. The preceding list of metadata components should be considered as exemplary and by no means comprehensive or limiting the scope of the present invention.
[0031] The personal content management system also provides programmatic mechanisms necessary to enable access to virtual information portfolio contents, including actual content. The personal content management system can also contain ancillary content information collected from distributed computing devices, rendering systems, and the files connected to a distributed communications network, including information collected using a variety of protocols. The present invention facilitates transparent software component transfers to target rendering systems by handling user authentication, electronic content transfer, transformation, rendering, copyright protection, and other services.
[0032] The present invention also allows a user to define, manage, and operate an autonomous electronic content marketplace. This aspect of the invention leverages innate content characteristics to facilitate low overhead content ownership transactions. A personal content management system can also provide systems and methods to define external user access policies to content within a virtual information portfolio. Much as users trade, barter, and borrow current physical media, such as books, CDs and DVDs, the present invention allows users to define policies and constraints surrounding such trading practices for their electronic content. This aspect of the invention is of particular significance for secure electronic content that requires a fine degree of sensitivity to the issues associated with copyright protection. While the present invention facilitates the trading of legally owned electronic content manifestations, the system also provides mechanisms to enable copyright protection.
[0033] It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.
BRIEF DESCRIPTION OF THE DRAWINGS
[0034] The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.
[0035] In the drawings:
[0036] [0036]FIG. 1 is a block diagram illustrating a distributed network where a user may access said network from a number of disparate access points and where electronic content manifestations may reside on different physical locations across said network.
[0037] [0037]FIG. 2 is a block diagram showing a logical view of a virtual information portfolio, including several logical content groupings.
[0038] [0038]FIG. 3 is a block diagram depicting an information flow that may be used for authentication purposes in a preferred embodiment to control access to a virtual information portfolio.
[0039] [0039]FIG. 4 is a block diagram illustrating interactions among system components facilities content acquisition, delivery, and rendering.
[0040] [0040]FIG. 5 is a Unified Modeling Language (UML) sequence diagram depicting a control flow enabling a user to access content requiring secure rendering using a remote wireless device.
[0041] [0041]FIG. 6 is a block diagram illustrating a structure which supports a virtual information portfolio's ability to manage and trade electronic content.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0042] Reference will now be made in detail to preferred embodiments of the present invention, examples of which are illustrated in the accompanying drawings.
[0043] [0043]FIG. 1 addresses two important objects of the present invention: content location and user access. FIG. 1 presents collections of electronic content 100 , 102 , and 104 , which, for the purposed of the embodiment illustrated in FIG. 1, are assumed to be owned by a single user. The present invention allows content 100 , 102 , and 104 , to reside at completely separate physical locations, represented in FIG. 1 by network servers 101 , 103 , and 105 . In a preferred embodiment, network servers 101 , 103 , and 105 can be interconnected via a common network backbone 106 . It should be apparent to one skilled in the art that alternative embodiments, including those in which network servers 101 , 103 , and 105 are physically connected to independent networks, are also possible and within the scope and spirit of the present invention. From a user's perspective, the present invention provides seamless access to content 100 , 102 , and 104 through a variety of access points 107 , which may include desktop computers, laptops, wireless computing devices, wireless communication devices, and other devices.
[0044] [0044]FIG. 2 presents a logical view of content location aspects of the present invention. FIG. 2 illustrates the use of a virtual information portfolio 207 to insulate users from the details of the physical layout of electronic content objects 200 , 201 , 202 , 204 , and 205 . In FIG. 2, content objects 200 , 201 , and 202 are shown to physically reside in network server 203 , while electronic content objects 204 and 205 are shown to reside in network server 206 . For the purposes of describing this aspect of the invention, one can assume that the aforementioned content objects legally belong to a single user.
[0045] Virtual information portfolio 207 is multi-layer software arranged in a multi-tier architecture. A presentation application layer on a user device (not illustrated) and provides an interface to data stored in, and services provided by, virtual information portfolio 207 . In the business logic tier, virtual information portfolio 207 consists of an interface layer that tracks content attributes, including user defined attributes, and allows users to group content based on those attributes. In addition, virtual information portfolio 207 serves as a logical layer that provides a mapping between how users organize and perceive their electronic content for their own purposes and where content objects physically reside within a network.
[0046] [0046]FIG. 2 illustrates a user who has organized electronic content into two logical content groups, 208 and 209 that contain different electronic content objects based on a user's preferred categorization scheme. For example, Logical Group Alpha 208 contains references to content objects 210 , 211 , and 212 that in actuality represent physical electronic objects stored in different locations across a network. While Content Object- 1 . 1 210 and Content Object- 1 . 3 211 are physically stored in Network Server- 1 203 , Content Object- 2 . 2 212 is physically stored in Network Server- 2 206 .
[0047] In a preferred embodiment, virtual information portfolio 207 can allow a user to manually create, delete, modify, and manipulate logical content groups. In addition, a user may add and remove individual content items, and create recursive structures. In alternative embodiments, the present invention may include the complementary use of electronic content indexing and classification systems and methods to aid in the automated organization of large volumes of content.
[0048] [0048]FIG. 3 illustrates a preferred embodiment in which biometric input system 301 and standard PKI techniques provide user 300 with authenticated access to the contents of virtual information portfolio 313 in a preferred embodiment. Before user 300 is granted access to virtual information portfolio 313 , user 300 performs a one-time registration step with registration service 305 . As part of this process, user 300 provides user registration data 302 , along with user biometric data 303 , to registration service 304 . User registration data 302 may include, but is not limited to, different degrees of demographic information about user 300 . User biometric data 303 is collected and transferred to registration service 304 through biometric input system 301 .
[0049] For the purpose of describing the present invention, biometric input system 301 may consist of a collection of hardware and software components capable of collecting, encoding, and communicating one or more biological metrics taken from user 300 with the user's consent. Such biometric measurements may vary in degrees of uniqueness and physical intrusiveness and may include fingerprinting, retinal scans, DNA sampling, and the like. Since both biometric and demographic data present significant privacy issues, the present invention may be extended by one skilled in the art to employ standard PKI asymmetric encryption techniques to securely exchange registration information 302 and 303 with registration service 304 . Registration service 304 communicates registration data 305 to PKI certification authority 306 , which encodes registration data 305 into PKI certificate 307 and delivers it to user 300 .
[0050] When user 300 requests access to virtual information portfolio 313 , personal content management system 310 allows user 300 to send PKI certificate 308 and user biometric data 309 for verification. Once personal content management system 310 has verified biometric information encoded in certificate 308 with the provided user biometric data 309 , user 300 may be granted access to virtual information portfolio 313 . While not explicitly depicted in FIG. 3, user 300 may control multiple virtual information portfolios through a single personal content management system, or may use multiple personal content management systems to mediate access to multiple virtual information portfolios. While the preceding description focuses on specific concepts associated with standard PKI and biometric identification techniques, it should be apparent to one skilled in the art that alternative approaches may be considered to address security and authentication issues without departing from the spirit or scope of the invention.
[0051] [0051]FIG. 4 illustrates activities and control flow associated with electronic content acquisition, management, and rendering. The present invention encompasses said activities for both protected and unprotected content. FIG. 4 illustrates two distinct logical flows.
[0052] With respect to unprotected content, user 400 may directly initiate content upload or transfer 411 to virtual information portfolio 407 . In such a scenario, personal content manager 405 can transfer data 406 , which can include content information, such as the physical location of the content, and optionally the content itself, to virtual information portfolio 407 .
[0053] In the protected content scenario depicted in FIG. 4, user 400 can interact with electronic content store 402 via programmatic or interactive means to browse and select protected content for purchase. Once user 400 decides which electronic content manifestation to purchase, information about the product 401 , such as a product identifier and payment information, to electronic content store 402 . Once payment information has been cleared by electronic content store 402 , electronic content store 402 may transfer electronic order confirmation 403 to personal content management system 405 . In a preferred embodiment, order confirmation 403 may contain an order identifier, a content identifier, and a product identifier. Such identifiers can allow personal content management system 405 to obtain content information 406 required by virtual information portfolio 407 to facilitate content rendering and presentation of said content to user 400 . Personal content management system 405 is capable of processing electronic order confirmations 403 from multiple electronic content stores 402 through order processing plug-ins 404 customized for individual order confirmation protocols.
[0054] Personal content management system 405 handles communications with virtual information portfolio 407 , which in turn is responsible for handling storage and content presentation. Content presentation can be handled through a series of presentation plugins 408 that may present content to user 400 using a variety of textual presentations, graphical metaphors, or other sensorial presentations. In addition, personal content management system 405 can transform and transfer content to external rendering device 410 using content adaptor plug-ins 409 . Such content adaptor plug-ins 409 may interact with external rendering device 410 to determine its rendering capabilities, and use information contained in ancillary content objects to transform the content for subsequent rendering in external rendering device 410 .
[0055] [0055]FIG. 5 illustrates a preferred message sequence as exchanged between user 500 , wireless device 501 , owned by user 500 , and personal content management system 502 , for the purposes of giving wireless device 501 access to specific content. User 500 can initiate the exchange by requesting a connection 503 via wireless device 501 . Wireless device 501 responds to said request by setting up a network connection 504 to personal content management system 502 . At that point, personal content management system 502 interacts with wireless device 501 to determine whether or not said device features necessary and up-to-date authentication software 505 required for authentication. If target wireless device 501 does not have necessary authentication software installed, or if an authentication software component is out of date, an up-to-date authentication software component can be distributed to said wireless device 501 for installation.
[0056] Once any necessary authentication software has been verified as installed in target wireless device 501 , an authentication sequence can be initiated by personal content management system 502 requesting user credentials 506 from wireless device 501 . At this stage, wireless device 501 requests biometric user input 507 from user 500 , which is to be used as part of data to be sent to personal content management system 502 for authentication purposes. User 500 provides requested biometric user input 508 , which is forwarded 509 by wireless device 501 to personal content management system 502 . If the user certificate matches the biometric data sent by wireless device 501 , personal content management system 502 may accept connection 510 , thus allowing user 500 to access the virtual information portfolio contents.
[0057] Once authenticated, user 500 can request access to content 511 that requires secure rendering for copyright protection reasons. Personal content management system 502 may communicate with wireless device 501 to verify 512 that software required to produce a secure content rendering is already installed on the target wireless device 501 . If the necessary software is not installed, or if said secure rendering software is out of date, personal content management system 502 may initiate installation of the required software. Once wireless device 501 has the necessary secure rendering software installed, personal content management system 502 can transform and transfer 513 content to target wireless device 501 .
[0058] In a preferred embodiment, personal content management system 502 can transfer content 513 to target wireless device 501 , thereby allowing user 500 to disconnect from network 514 after said data transfer is complete, thus minimizing carrier charges for metered wireless network usage. Alternative embodiments may utilize electronic data streaming techniques to transfer electronic content, as needed, to target wireless device 502 for secure rendering in situations where network access costs are not an issue. Once wireless device 501 receives the content, connections with personal content management system 502 can be terminated 514 . From that point on, user 500 may access content directly from wireless device 501 , and may produce a secure rendering 515 that does not require further authentication or network connectivity.
[0059] [0059]FIG. 6 illustrates data structures that may be used in a preferred embodiment to support the ability of a virtual information portfolio 600 to create an autonomous electronic content marketplace. Virtual information portfolio 600 maintains an internal look-up table 601 to keep track the information necessary to present the contents of virtual information portfolio 600 to a user, and to locate the actual electronic content data. In a preferred embodiment, look-up table 601 keeps all entries indexed by unique content identifier 602 . Such a content identifier 602 may follow existing content identification schemes, such as International Standard Book Number (ISBN) or Digital Object Identifier (DOI), or it may employ an entirely new, unique content identification and numbering scheme. Look-up table 601 may also contain content metadata 602 , content location 603 , and sharing policy definition 604 . It should be apparent to one skilled in the art that the number of fields may be increased or decreased, and that additional fields can be substituted for those set forth above, without departing from the spirit or scope of the invention.
[0060] Content metadata 602 may contain a varying number of data fields that describe the electronic content manifestation in further detail, including, but not limited to, title, author, publication data, and publisher. Content location 603 provides an unambiguous description of the physical content location. For content location 602 expression purposes, look-up table 601 may use a standard resource locator specification, such as a Uniform Resource Locator (URL), or similar scheme. Sharing policy definition 603 provides a user with the flexibility to control how electronic content manifestations may be presented to outside users and programmatic entities.
[0061] Through sharing policy definition 603 , the present invention extends a user's ability to trade electronic content outside the context of pre-established electronic commerce infrastructures, and allows a user to exploit the competitive and financial advantages of a more flexible, autonomous content market. Sharing policy definition 603 centers around four main areas: content visibility 606 , content actions 607 , content actions constraints 608 , and rights management 609 .
[0062] Content visibility 606 allows a user to define whether particular content is private, public, or controlled. Private content may be visible to only authenticated users who have previously registered with a registration service, while public content may be visible to any user who may or may not have previously registered with said registration service. Controlled content refers to electronic content manifestations that are visible to certain authenticated users of other personal content management systems within the network. Through a distributed registration service, authenticated users may be organized into groups that facilitate specification of access control policies for controlled electronic content. It is important to note that such user groupings may be associated with corporate organizational information stored in a Light-weight Directory Access Protocol (LDAP) service, or may be based on less structured organizational units such as freely associated network user communities. A goal of the invention is to allow users to define which external users have access to specific content within a virtual information portfolio.
[0063] Content actions 607 allow a user to specify which operations are allowed for a specific electronic content manifestation. Content actions 607 are only available to users who meet criteria specified in content visibility 606 . In a preferred embodiment, virtual information portfolio 600 gives a user control over at least the following actions: content previewing, content borrowing and content review editing. It should be apparent that one skilled in the art could extend the range of supported virtual information portfolio operations and remain within the scope and spirit of the present invention.
[0064] For content previewing purposes, the constraint may specify which portions of the electronic content manifestation are available for preview. It is important to note that for secure content, the length and nature of the electronic content preview may be specified by the content creator at content creation time. For content borrowing purposes, the constraint may help a user place chronological and financial boundaries around such a transaction. For example, a user could specify a time limit of 48 hours and a price of five U.S. dollars for a particular content to allow for the checkout of that content for said price to an external user. In another example, a user could specify no time limit and a price of ten U.S. dollars for particular content to allow for the permanent sale of the content to external users. In essence, virtual information portfolio 600 may use look-up table 601 to support the emergence of independently owned and operated personal digital marketplaces supporting a variety of content usages and business models in a noncentralized fashion.
[0065] The present invention addresses issues of copyright protection in lookup-table 601 by providing a field within sharing policy definition 605 that tracks the digital rights management (DRM) requirements 609 particular content. In a preferred embodiment, this field may contain values indicating that the content does not require any copyright protection, or the identifier for the copyright protection scheme required by the electronic content. Such copyright protection scheme identifiers may point to industry standards, such as those defined by the Electronic Book Exchange (EBX), or vendor-specific techniques. It should be apparent to one skilled in the art that the example values described above may be extended with additional DRM techniques as they become generally accepted and available and should not be construed as limiting the scope of the present invention.
[0066] While the invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to those skilled in the art that various changes and modifications can be made therein without departing from the spirit and scope thereof. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. | A system and methods supporting flexible content usage in distributed environments, where users may have access to electronic content from multiple disparate sources and rendering systems. The invention consists of a personal content management system and a collection of virtual information portfolios. The personal content management system manages user authentication, handles content uploads either from a public source such as a user or from an electronic content store, and transforms the content for specific rendering devices, thus providing ubiquitous access to said electronic content. The virtual information portfolio supports content distribution across multiple physical locations while providing support for multiple logical content groupings, including recursive content groupings. The virtual information portfolio allows logical content structure to be presented to users through a variety of formats, and enables the user to sell, share, lend, exchange, and trade digitally protected and non-protected electronic content directly with other users or entities. | 6 |
FIELD OF THE INVENTION
This invention relates to wear-resistant coatings, and more particularly, to a process for applying a wear-resistant coating to the inner diameters of automotive engine cylinder bores.
BACKGROUND OF THE INVENTION
The auto industry has long sought to use lightweight materials as the base material for engine blocks so as to reduce overall vehicle weight and thus enhance fuel efficiency. Use of such materials (e.g., aluminum and its alloys) for automotive componentry such as engine heads and blocks often requires the incorporation of insert materials such as steel or cast iron to provide wear resistance which is not attainable with the lighter material on contact surfaces such as valve seats and cylinder bores. In particular, aluminum engine blocks require some type of wear-resistant surface on the cylinder bores, for example, to accommodate the sliding action of the piston sealing rings.
Previous approaches to this problem have been to use cast-in-place iron or steel liners in the cylinder bores, or to fashion the engine block out of materials such as the 390-type aluminum alloys, wherein a high fraction of primary silicon particles at the surface of the material provides the necessary wear resistance. Liners were found to be too heavy, limited heat conduction to the water jacket, required specialized facilities for either casting in place or inserting in the engine block, and were expensive to install. The use of 390 alloy for engine blocks, while solving the wear resistance problem, introduces other problems, such as difficulty in machining the material and specialized steps required to produce the most desirable wear surface.
Other approaches to the cylinder bore surfacing problem for aluminum alloys have used an electrodeposition process to produce layers which incorporate silicon carbide particles into a nickel matrix, such as the Nikasil process (registered trademark of the Mahle Company). The drawback of this technique is the complexity of the process for selective plating of engine cylinders requiring either localized deposition or extensive and elaborate masking. Wear-resistant coatings have also been deposited on engine parts using chemical vapor deposition (CVD) techniques, as disclosed in U.S. Pat. No. 5,226,975 (Denton et al.). These processes, however, can require 10 to 60 hours for a satisfactory coating to be deposited and thus are far too slow for assembly line purposes
Thermal spraying systems represent another approach to applying wear-resistant coatings to cylinder bore surfaces at processing rates significantly greater than other coating processes, such as CVD. These systems in general rely on a combination of heat and momentum to cause droplets of the coating material to conform and bond to the surface being coated. Different thermal spraying systems employ varied methods of imparting heat and momentum to a stream of droplets which will form the coating. One such system is the high velocity oxy-fuel (HVOF) process, such as disclosed in U.S. Pat. No. 5,019,429 (Moskowitz et al.). In the HVOF process, droplets attain a high velocity with high pressure gas as a transport medium and bond through plastic deformation upon impact with the coated surface. HVOF has been used for coating engine cylinder bores, as disclosed in U.S. Pat. No. 5,080,056 (Kramer et al.). The HVOF process, however, is slow (60 grams/minute), noisy (transport gases flow at supersonic speeds), and produces excessive heat which must often be dissipated from the workpieces by ancillary cooling schemes.
Another thermal spraying method, plasma spraying, uses a plasma arc to heat gases which heat and accelerate a droplet stream which is directed at a substrate rotating around a plasma torch by high pressure gas, as disclosed in U.S. Pat. No. 4,970,364 (Muller). Droplet velocities are lower than in the HVOF process but are heated to a higher temperature so that they are in a molten state upon reaching the substrate in order to provide a good bond. Other thermal atomization techniques, such as those used for powder production (Fabrication of Powders by the Rotating Electrode Process, Champagne and Angers, The International Journal of Powder Metallurgy & Powder Technology, Volume 16, No. 4, 1980), use a rotating rod of the feedstock material to impart momentum to the melted droplets. Powder production processes, however, are inadequate to form the required cylinder bore coating.
SUMMARY OF THE INVENTION
The present invention provides a rotating electrode coating process for depositing a wear-resistant coating at a high rate onto the inner surfaces of cylindrical objects, such as automotive engine cylinder bores. In particular, a method is disclosed for making an aluminum alloy automotive engine block comprising the steps of casting an engine block of aluminum alloy, depositing a wear-resistant coating onto cylinder walls in the engine block by melting the tip of a rotating rod, made of an iron-based alloy or other comparable composite material, with a plasma torch within the engine block cylinders, and finishing the cylinder walls to a chosen size and surface topography by conventional boring and honing practices.
The wear-resistant coating, which preferably is of an iron-based or steel alloy, is applied by one preferred method to the inner wall of a cylinder in an aluminum alloy engine block by positioning a transferred arc torch within the cylinder, striking an arc between the torch and a consumable rod, made of an iron-based alloy or other comparable composite material, such that the arc end of the rod melts, rotating the rod to eject a diametral spray pattern of molten droplets from the arc end of the rod to the cylinder inner diameter, and translating the rod and the torch generally along the central axis of the cylinder such that the ejected droplets impact the wall of the cylinder in a molten state to form an evenly distributed coating on the cylinder.
Preferably, a plasma heated process is used in which a plasma arc is struck between the torch and the rod with an argon-oxygen gas mixture used to produce the plasma gas, preferably at a rate of approximately 24 to 32 liters of argon per minute and oxygen at a rate of 11 to 17 liters per minute. The torch is preferably cooled with argon gas, and by partially enclosing the cylinder during deposition of the coating the plasma gas and the cooling gas may purge the cylinder and thus control the atmosphere therein. It has been found that good results are achieved when a steel alloy rod, for example, AISI 1045 steel, having a mean diameter of between approximately 10 mm and 20 mm, is melted by the plasma arc and rotated at a velocity of between approximately 14,000 rpm and 18,000 rpm to produce a deposition rate of at least 195 grams per minute.
In addition to using a plasma transferred arc apparatus for melting the feedstock rod, other apparati for producing intense heat may also be used, such as lasers, electron beams, and flames. Furthermore, any metal or conductive composite material capable of conducting a transferred arc may be used as the feedstock for the process. Grey iron is a desirable feedstock material due to the self-lubricating aspects of the incorporated graphite.
Thus, an object of the present invention is to produce a wear-resistant coating, such as cast iron or steel, on an aluminum cylinder bore surface by a plasma rotating electrode thermal spray process.
A further object is to provide a high deposition rate method for coating cylinder bores of an internal combustion engine.
Another object of the present invention is to provide a method to thermally spray wear-resistant coatings onto an aluminum engine block cylinder bore which is feasible from both a technical and manufacturing standpoint in the sense of being able to be incorporated into an online engine build facility.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an aluminum alloy engine block showing the cylinders as conventionally arranged.
FIG. 2 is a schematic representation of the rotating electrode coating method of the present invention.
FIG. 3 is a schematic diagram of the apparatus used for applying a wear-resistant coating to a cylinder of an engine block using the rotating electrode coating method of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
An engine block 10 cast of an aluminum alloy, for example type 319, is shown in FIG. 1 having six cylinders 12, three on either side of engine block 10. Each cylinder 12 has a cylinder bore 14 into which a piston (not shown) will be fitted for operation in the conventional internal combustion engine sense. To prevent wear of bore 14 by the piston and its sealing rings, a wear-resistant coating 16 is applied using a rotating electrode coating process as further described below.
FIG. 2 illustrates the basic concept of powder production and thermal spraying, which, as discussed below, is modified for the present invention. The coating material to be deposited on cylinder bore 14 is formulated into a rod 20 which provides the feedstock. The coating material of rod 20 is both electrically conductive and can be melted, such as AISI 1045 steel and, additionally, does not volatilize directly. Insulator 22 electrically isolates rod 20 from connecting boss 24 which is attached to motor 26 (FIG. 3) which provides rotation. Speeds of up to 20,000 rpm can be used, with rods of up to 4 cm in diameter. A non-consumable electrode 28 provides the counter electrode, and an arc 30 is struck between the electrodes (rod 20 and electrode 28), and a plasma jet is formed with gases 31 routed by shield 33 to flow between the electrodes. Molten material formed on the surface of rod 20 is ejected by centrifugal force and forms a droplet spray 32. Brush 34 provides the electrical contact to the rotating electrode, which, in FIG. 2, is rod 20.
The two-electrode arc process shown in FIG. 2 can typically only deliver a limited amount of superheating to the molten droplet spray 32 which, while sufficient for powder production, is insufficient for producing low porosity coatings on cylinder bores. To provide additional heating of the ejected droplets, a plasma-based torch is used to replace the non-consumable electrode 28, as shown in FIG. 3. Typical plasma torch configurations (not shown) include the transferred arc, in which the surface of feedstock rod 20 acquires a positive charge relative to the gun cathode, with a neutral or grounded nozzle, and a non-transferred arc or torch, in which the nozzle becomes the anode. For applying metal alloy coatings to cylinder bores, a transferred arc plasma torch 38 has been used in conjunction with electrical isolation of feedstock rod 20, as is further described below.
The preferred arrangement for cylinder bore coating is illustrated in FIG. 3. The consumable feedstock rod 20 rotates at a high rate of speed, preferably between 14,000 rpm and 18,000 rpm, so that ejected molten droplet spray 32 (FIG. 2) travels under the influence of centrifugal force to the cylinder bore 14 to form coating 16 thereon. Maximum rotational speeds of rod 20 would be on the order of 20,000 rpm. Rod 20 can translate along cylinder center axis 36 in association with movement of the transferred plasma-arc torch 38 as material is consumed to form coating 16. Plasma-arc torch 38, which is, for example, a modified Thermal Dynamics PCM-100 plasma transferred arc cutting torch, can be used to achieve melting of consumable anode rod 20. Head assembly 40 contains torch 38, conduits (not shown) for transmitting gas (typically argon or some inert gas) to torch 38, electrical connections to torch 38, and conduits (not shown) for routing plasma gas and cooling fluid gas to torch 38.
Plasma plume 42 is generated by torch 38 and is projected onto the end of the rotating feedstock rod 20. The heated gases from plasma plume 42 aid in superheating ejected molten droplet spray 32 from feedstock rod 20 and may also provide additional gaseous flow to transport spray 32 to cylinder bore 14. The centrifugal force of rotating rod 20, however, is the main driving force for producing the thermal spray morphology of the resulting coating 16.
Other intense and concentrated heat sources could alternatively be used to melt rotating rod 20, such as lasers, electron beams, and flames. Referring again to FIG. 3, head assembly 40 can contain a laser 38 which generates laser beam 42 directed at rod 20. Droplet spray 32 is formed as discussed above when rod 20 melts and is rotated to eject the molten droplets. Likewise, head 40 can contain an electron beam generator 38 which generates an electron beam 42 to melt rod 20.
Consumable feedstock rod 20, which is melted to form droplet spray 32, preferably is an iron-base or steel alloy, but could include other metals and composites which are electrically conductive and not volatilized by the plasma 42. Essentially, any metal or conductive composite material capable of conducting a transferred arc may be used as the feedstock rod 20 for the process. Grey iron, which for purposes of this disclosure is an iron-based alloy, would be advantageous as feedstock rod 20 due to the self-lubricating aspects of the incorporated graphite. Grey iron has been used in conventional liners with the graphite droplets acting to minimize scuffing while also providing pockets for oil retention. Gases for nitriding or carburizing could also be fed through rod 20 or as the plasma forming gases.
Torch 38 is operated using a plasma preferably comprising a combination of argon and another diatomic gas. Combinations of argon/oxygen, argon/nitrogen, and argon/hydrogen may be employed. Argon is preferably used as the cooling gas. Table 1 indicates typical gas flows for torch 38 operation.
TABLE 1______________________________________Plasma gas compositions and flow rates.Plasma Gas Cooling Gas______________________________________1. N.sub.2 : 14 l/min Ar: 140 l/minAr: 28 l/min2. H.sub.2 : 14 l/min Ar: 140 l/minAr: 28 l/min3. O.sub.2 : 14 l/min Ar: 140 l/minAr: 28 l/min______________________________________
The ratio of diatomic gas to inert gas may be altered to have the diatomic gas comprise up to 80% of the plasma.
The ends 13 of substrate cylinder 12 are preferably partially enclosed during the coating process to allow the plasma and cooling gases to purge the cylinder and control the atmosphere. End section 44 is attached for that purpose (FIG. 3). Failure to control the atmosphere may cause droplet spray 32 to travel through air during flight to cylinder bore 14, resulting in oxidation of the droplets. The effects of plasma gas upon droplet size and coating 16 structure have been evaluated using the three gas compositions shown above in Table 1. The mean droplet size for each plasma gas combination is given below in Table 2.
TABLE 2______________________________________Mean droplet size vs. plasma gas.Plasma Gas Mean Droplet Size (um)______________________________________Ar/N.sub.2 247Ar/H.sub.2 247Ar/O.sub.2 209______________________________________
Coating 16 deposit rates for the plasma rotating electrode process of the present invention are shown in Table 3.
TABLE 3______________________________________Melt rate vs. plasma gas.Plasma gas Melt rate______________________________________Ar/N.sub.2 157 gm/minAr/H.sub.2 142 gm/minAr/O.sub.2 195 gm/min______________________________________
The highest melt rate, 195 gm/min, occurred when using argon/oxygen plasma. Melt rates for all plasma gases investigated are highly favorable when compared with typical deposition rates of 40-60 grams/min for conventional thermal spray processes such as air plasma spray (APS), high velocity oxy-fuel (HVOF) and wire-arc. With the demonstrated coating rates in Table 3, the method of the present invention can be used satisfactorily in manufacturing settings for coating the internal cylinder bores of an aluminum cast engine block with a wear-resistant coating.
To achieve good adhesion of coating 16, cylinder 12 is prepared for coating by blasting cylinder bore 14 with chilled iron shot. Alternatively, cylinder bore 14 is grit blasted with an appropriate abrasive material, such as number 12 alumina, at between 60 psi and 95 psi prior to spray depositing the coating 16 on bore 14. Other cylinder bore 14 preparation methods known to those skilled in the art and suggested by this disclosure can be also be used.
Although the preferred embodiment of the present invention has been disclosed, various changes and modifications may be made without departing from the scope of the invention as set forth in the appended claims. | A method for coating the internal cylinder bores of a cast aluminum engine block comprising the steps of casting an engine block of aluminum alloy, thermally spraying a wear-resistant coating onto cylinder walls in the engine block by melting the tip of a rotating iron-based alloy rod with a plasma torch within cylinders in the engine block, and honing the cylinder walls to a chosen size. | 2 |
BACKGROUND OF THE INVENTION
Field of the Invention
This invention pertains to the field of hand tools. More particularly, this invention pertains to a hand-operated tool or apparatus for use in forming bends in certain bendable tubes such as, for example, tubes through which electrical wires pass, known as "conduit."
BACKGROUND OF THE INVENTION
Tubing is used in the construction industry to convey gasses and liquids, as well as to support electrical wires, from place to place. In the building industry, most tubing is used to direct liquids and electrical wires throughout a structure.
While there is some use of plastic tubing, the tubing used to contain wires is generally made of metal and known as "conduit". The reason for using metal over plastic in this instance is that conduit is usually installed after the building is partially or fully constructed and must be bent to follow the contours of the building such as around columns, pipes, pilasters, floor joists, etc., and the tubing must maintain its shape after it is bent around these obstructions. Metal tubing is more easily bent and holds its shape far better than plastic tubing.
The metal conduit generally used to carry electrical wires carries the generic name "Electrical Metal Tubing" or "EMT" conduit. It is usually made of aluminum alloy and has a relatively thin wall. Bending EMT conduit has historically been accomplished with a manual tube-bending tool of the type generally shown in U.S. Pat. Nos 1,379,016; 1,754,635; 1,878,754; 2,233,393; 2,349,525; 2,381,064; 2,630,033; 3,063,314; 4,587,832; and U.K. Pat. No. 2,092,036, as well as with a few machines of the type shown in U.S. Pat. No. 3,691,815 and Italian Pat. No. 629,437.
In these patented inventions, the conduit tube is generally laid in a groove formed in the convex edge portion of a shoe or bending anvil, clasped or temporarily held at one end thereof by a collar or hook, and the anvil rotated or rolled against a solid surface along the convex edge by force applied to a handle extending outward from the anvil on the opposite side from the groove. The desired degree of bend is usually "eyeballed", however, some attempts have been made to reduce the estimated degree of bend to a more precise measurement, see U.S. Pat. Nos. 2,349,525; 3,063,314; and, 4,587,832.
Where wires traverse a wall containing obstructions, such as columns, pipes or ducts, the conduit may be bent into a single offset or a double offset, the latter referred to as a "saddle". An offset is merely a displacement in the tube formed by two spaced-apart bends or arcs of the same angularity but in opposite directions. The span of tubing between the two bends is called the "offset span" and may vary in length depending upon a number of factors such as the total offset distance, the required acuteness of the offset angle, etc.
While bending a tube using the hand tools shown in the prior art is subject to certain inaccuracies in angularity, forming an offset having two bends is more critical as the inaccuracies in each bend rarely compensate each other and, more often than not, they accumulate to cause a larger overall error. An inaccurate offset means that one leg of the tube will either extend too far from the wall to make mounting difficult or fit too close such that the other leg is pulled out of its wall attachment. The prior art has not cured this problem.
Even worse are the inaccuracies that arise in the formation of a saddle. A saddle comprises two offsets in close opposition so that the result is tubing whose major conduit axis lies in a common plane, for example, the plane adjacent a flat wall, and where one offset extends the tubing out of the plane of the wall and another offset returns the tubing to the plane to permit the tube to pass around the obstruction. Saddles contain four angles, each with its own inaccuracy. The inaccuracy of each angle, created by the mere "eyeballing" of hand-bending, as aforedescribed, may and often does create such disparity in the offset spans that the result is unacceptable from a building code point of view, is sloppy and looks poor, and results in the need to rebend the offset angles or redo the whole saddle, thus causing a waste of material and a loss of work time.
These problems have been completely overcome in the instant invention. This invention is a compact, sturdy apparatus for use in rapidly forming very accurate offsets and saddles. An offset of extreme accuracy may be formed in one swift motion; a saddle also of exact dimensions may be formed in two swift motions. The astonishing accuracy and swift accomplishment of forming these bends using this invention saves energy, work time and material. The ease of use of the invention allows accurate offsets and saddles to be formed by less experienced personnel such as trainees. Offsets need not be redone, tubing is not wasted and work may continue without undue interruption.
SUMMARY OF THE INVENTION
This invention is an apparatus for rapidly forming accurate offsets in bendable tubes comprising a tube bending anvil, containing an arcuate edge portion having formed therein a planar tube-receiving groove and a tube-retaining means for clasping the tube at one end of the groove, means for arranging the tube-receiving groove normal to a flat work surface and accurately positioning it above the surface with the tube-retaining means at the apex thereof, the means including a mounting plate and legs on the plate for supporting it vertically upon the work surface. The invention also includes means to adjust the height of the anvil accurately above the work surface and the use of a second tube-bending anvil having a handle extending therefrom for providing a combination of downward pressure on a tube mounted in the first anvil above the work surface and applying rotative force to the second anvil to simultaneously cause the first offset bend or arc to be formed about the first anvil, above the work surface, and the second offset arc formed about the second anvil adjacent the work surface.
The main object of this invention is an apparatus for forming offsets and saddles in bendable tubing with accuracies and speed heretofore unknown in the prior art. Other objects of the invention include a means for removing the estimation in the normal bending operations in forming offsets and saddles, a means of swiftly and accurately changing the degree of offset needed for a particular operation, means for forming offsets and for separately forming saddles without the use of large equipment, and apparatus that is sturdy and compact and easily transported from job site to job site, that is amenable to making offset bends of a variety of angles and radii and an apparatus capable of bending a variety of sizes of tubes. These and other objects of the invention will appear more clearly upon reading the following Description of the Preferred Embodiment taken together with the drawings appended hereto. The scope of protection the inventor seeks may be gleaned from a fair reading of the claims that conclude this specification.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a top plan view of a typical wall having a change in wall thickness showing a required offset formed in conduit attached to the wall;
FIG. 2 is a top plan view of a typical wall having a vertical pipe adjacent thereto showing a required saddle formed in conduit attached to the wall;
FIG. 3 is a front plan view of one embodiment of the means to support the tube-bending anvil of this invention above a work surface.
FIG. 4 is a front plan view of another embodiment of the means to support the tube-bending anvil of this invention above a work surface.
FIG. 5 is an end view of the anvil and mounting plate shown in FIG. 4;
FIG. 6 is a cross-sectional view of part of the slot and channel taken along lines 6--6 in FIG. 5.
FIG. 7 is an isometric view of one embodiment of the legs supporting the plate and anvil on the work surface with the anvil removed for clarity.
FIG. 8 is a front plan view of a typical second tube-bending anvil used in conjunction with the apparatus of this invention.
FIG. 9 shows the embodiment of FIG. 3 being used to form an offset.
FIG. 10 shows the offset produced in FIG. 9.
FIG. 11 shows the embodiment of FIG. 3 being used to form a saddle.
FIG. 12 shows the saddle produced in FIG. 11.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Shown in FIG. 1 is a top plan view of a typical wall 1 having an area 3 of one thickness and an area 5 of greater thickness. Adjacent one surface (generally the inside surface) of wall 1 is mounted an elongated tube or conduit 7, of the EMT variety previously mentioned, carrying electrical lines 9. Conduit 7 is mounted adjacent the surface of wall 1 by a series of spaced-apart fasteners 11 that generally have a conduit enclosing portion 13 and a mounting pin 15 extending outward therefrom for insertion in a hole 17 drilled or otherwise formed in wall 1. Conduit 7 traverses the span between wall thickness 3 and wall thickness 5 through an offset 19 that comprises a first offset bend or arc 21 and a second or return offset bend or arc 23. The portion of conduit 7 traversing the distance between arcs 21 and 23 is termed the "offset span" 25. The measured distance between the axes of the straight portions of conduit 7 outside of offset 19, shown as v--v and w--w, is referred to as the "offset distance" x.
As shown in FIG. 2, where conduit 7 is required to bend around or traverse an obstruction such as a pipe 27, a saddle 29 is required to be formed in conduit 7. Saddle 29 contains two offsets in opposed or face-to-face arrangement and comprises two first offset bends 21, spaced on opposite sides of pipe 27, and two separated but closer spaced return offset bends or arcs 23. The distance between return offset bends 23 may vary according to the width of the projection outward from the wall around which conduit 7 is to traverse. It may be small to transverse a pipe or larger, should the obstruction be a wide air conditioning or heating duct, etc. The lateral distance between conduit axis v--v and conduit span axis w--w as shown in FIG. 2 is still termed the "offset distance" x.
One embodiment of this invention is shown in FIG. 3 and comprises a tube-bending anvil 31, usually made of metal, such as cast iron, to withstand the rigors of tube bending, that contain an arcuate edge portion 33 of set radius spanning ends 35 and 37. A planar tube-receiving groove 39 is formed in edge portion 33 between ends 35 and 37 of a radius sufficient to receive a bendable tube therein. The axis of groove 39 lies in a plane z--z (FIG. 5). At edge portion end 35 is located tube-retaining means 41 which is used to temporarily anchor a tube in groove 39 for the bending operation. Means 41 is shown to comprise a hook 43 of short length extending up and over top of groove 39 and terminating at end 45. An offset groove 47 is formed in anvil 31, below hook 43, in a downward or inward direction from groove 39. In practice, a tube is inserted into offset groove 47 under hook 43 and then rotated to engage hook 43 and place it tangential to groove 39 at end 35. To remove the tube the steps are reversed. Means 41 may also take the form of a collar located at edge portion end 35 into which the tube is temporarily inserted, see U.S. Pat. No. 1,878,754.
Means 49 is next provided to arrange anvil 31 and its tubereceiving groove 39, with its plane y--y, normal to a flat work surface and accurately positioned thereabove with said means 41 at the uppermost position or apex of arcuate edge portion 33.
Means 49, comprises a mounting plate 51 defined by spaced-apart parallel side edges 53a and 53b, spaced-apart parallel top and bottom edges 55a and 55b and front surface 57 and rear surface 59. One embodiment of means 49 is shown in FIG. 3 to include first and second series of apertures 61 and 63 in spaced-apart vertical arrangement, series 61 positioned near plate side edge 53a and second series 63 positioned near plate side edge 53b. Said apertures 61 and 63 align with spaced-apart apertures 67 and 69 that are formed in anvil 31 near ends 35 and 37. First and second series of apertures 61 and 63 are arranged to adjust anvil 31 at specifically desired offset distances "x" above work surface 71 in usable increments such as half inch or quarter inch. These distances can be established using the measured indicia "I" scribed up front surface 57 of plate 51 near plate side edge 53a. This arrangement provides for accurate offset forming within the distances required of most construction operations. A pair of pins 73a and 73 b are inserted in apertures 67 and 69 and adapted for insertion in the aligned apertures of first and second series 61 and 63 to anchor anvil 31 against plate 51.
A first vertical slot 75, formed through plate 51 may be included, generally centrally located or centermounted between side edges 53a and 53b and adapted to receive therethrough a threaded pin or bolt 77 extending from a rotatable handle 79 and adapted to be threadably received in a nut 81 that is adapted to slide in a channel 83 formed in plate rear surface 59 (see FIG. 6). Anvil 31 may be moved into precise adjustment above work surface 71 and held against plate 51 by tightening clamp handle 79 and thereafter rigidly retained thereagainst by inserting pins 73a and 73b into the appropriate apertures of first and second series 61 and 63.
Another preferred embodiment of means 49 is shown in FIG. 4. First vertical slot 75 is shown in combination with a second vertical slot 85, formed in mounting plate 51 and spaced apart from first vertical slot 75, having parallel, spaced-apart opposed slot edges 87 and 89. Slot edge 87 is provided with a series of serrations 91 substantially along its entire length. Pin 73b is sized to pass freely up and down second slot 85 when clamp handle 79 is loosened and anvil 31 rotated slightly counterclockwise to allow it to move up and down to different distances above work surface 71. Upon reaching the desired distance, anvil 31 is rotated slightly clockwise to establish tube-retaining means 41 in the uppermost or apex position and clamp handle 79 is tightened against nut 81 and thereafter a tube is inserted in tube-retaining means 41 as shown in dotted outline. Pin 73b is now in contact with serrations 91 and, as downward pressure is applied to the tube extending from retaining means 41 above tube receiving groove 39, for the purpose of starting to form the offset, pin 73b jams against serrations 91 to prevent any vertical inter-movement between anvil 31 and mounting plate 51.
For more rigidity in the apparatus, a third vertical slot 93 is shown formed in plate 51 spaced apart from second vertical slot 85 and on the opposite side therefrom from first slot 75. Third vertical slot 93 is bordered by parallel spaced-apart slot edges 95 and 97 wherein slot edge 97 has formed therein a series of serrations 99. Just as in the previous embodiment, pin 73a is adapted to move freely in slot 93 when anvil 31 is rotated slightly counter clockwise and then moves into contact with serrations 99 when it is "straightened" so that pin 73a jams against serrations 99 to prevent vertical movement during subsequent use of the apparatus.
The apparatus is supported on work surface 71 by legs attached to plate 51. In FIG. 7 is shown one embodiment of such a support. A first "L-shaped" leg 101 is provided, attached to plate rear surface 59 by bolts 103 or welding (not shown) or the like. Leg 101 has a vertical portion 105 located adjacent plate side edge 53a and a horizontal portion 107 extending along plate bottom edge 55b and beyond plate 51. A vertical support bar 109 extends down plate rear surface 59 adjacent plate side edge 53b and is attached to horizontal leg portion 107 by welding at 111, said bar attached to plate 51 by bolts 113.
A second "L-shaped" leg 115 of terminal length is provided, having a first horizontal portion 117 extending outward from plate 51 and attached thereto at one end 119 by a hinge 121 and a second horizontal portion 118 extending substantially parallel to the plane of plate 51. Hinge 121 comprises two hinged tabs 123 and 125; tab 123 is welded or otherwise attached to plate rear surface 59 and leg end 119 is attached to tab 125 a short distance out from hinge pin 127 to allow leg 115 to swing from its support position in front of plate 51, shown in solid outline in FIG. 7, around behind plate 51 to a storage position, shown in dotted outline in the same Figure.
In FIGS. 3, 4 and 5 are shown another embodiment of support legs for plate 51. The same first "L-shaped" leg 101 and vertical support bar 109 are used, however, second "L-shaped" leg 115 has been replaced. An opening 131 is formed in the lower corner of plate 51, at the junction of plate side edge 53a and bottom edge 55b. A short, hollow sleeve 133 is positioned in opening 131, arranged normal to plate 51 and rigidly attached thereto such as by welding. A short stub 135 having terminal ends 137a and 137b is slidingly received in sleeve 133 and arranged normal to plate 51 with ends 137a and 137b extending from opposite sides of plate 51 to provide front-to-rear support to the apparatus. A cut-out 139 is made in anvil 31 to allow said anvil to avoid interference with sleeve 133 and moved closer to work surface 71.
To form an offset or a saddle with anvil 31 a second anvil 141 is needed. Second anvil 141 is generally shown in FIG. 8 to comprise a shoe 143 containing an arcuate edge portion 145 having formed therein a planar tube-receiving groove 147 terminated at groove ends 149 and 151 and a tube-retaining means 41 such as a hook 43 and associated groove 47 for temporarily clasping a tube at end 149 of groove 147. A handle 153 extends from a socket 155 located on the opposite or concave side of edge portion 145 and attached to edge portion 145 by webbing 157. As shown in FIG. 9, an offset is formed in conduit 7, an offset distance "x", by mounting anvil 31 above work surface 71 the distance "x" and thereafter positioning conduit 7 in tube retaining means 41 located at the highest point or apex of edge portion 33. Second anvil 141 is thereafter operatively positioned on conduit 7 spaced apart from first anvil 31 with its tube-receiving groove 147 aligned in common plane y--y with tube-retaining groove 39 of anvil 31 and tube-retaining means 41 of each anvil facing away from each other. The operator's foot or arm is place on the top of second anvil 141 and vertical downward force is applied thereto. Simultaneously, handle 153 extending from second anvil 141 is rotated from its outwardly angled initial position, shown in FIG. 9 toward the vertical or inward toward plate 51. The simultaneous downward pressure on conduit 7 and the rotation of second anvil 141 causes second offset arc 23 to be formed in groove 39 of first anvil 31 and first offset arc 21 to be formed in groove 147 of second anvil 141. The resulting offset is shown in FIG. 10. It should be noted that only one setting is needed to be made for first anvil 31 and only one bending operation performed to make the full offset.
To make a saddle, the first offset, shown in FIG. 10 is simply reversed as shown in FIG. 11 and the upper level displaced portion of conduit 7 is reinserted in first anvil 31. A similar downward stroke and rotation of second anvil 141 is performed as shown in FIG. 11 and the full saddle is formed in this second motion. The resultant saddle is shown in FIG. 12. | A tube bender for making accurate offsets and saddles in electrical conduit wherein a first tube-bending anvil is adapted to be positioned flat against a mounting plate at various specified distances above a flat work surface, the distance of the offset or saddle, the plate and anvil being supported vertically above the surface on legs extending outward from the plate, the anvil used in cooperation with a second, hand-held tube-bending anvil, wherein a bendable tube supported therebetween can be formed into an offset with one downward motion applied to the second anvil for displacing the electrical conduit the distance of the offset and wherein a saddle may be formed by doubling an offset. | 1 |
RELATED APPLICATION
This is a;
Continuation-in-part of Ser. No. 139,441, now abandoned
Filed: May 3, 1971
Title: Filament Winding Apparatus And Method
Inventor: Rexford H. Bradt
OBJECTS OF THE INVENTION
It is the object of this invention to provide a practical process for making, handling and winding strands of thermoplastic materials or thermoplastic materials in combination with other plastic materials or reinforcements to form useful shapes.
Another object is to provide a continuous process and apparatus which will make wound shapes from thermoplastic windable materials.
Yet another object is to make stronger pipe and the like from highly stretch oriented peripherally wound thermoplastic materials.
BACKGROUND OF THE INVENTION
The winding of assorted plastics and rubbers to make cylindrical articles has long been practiced. Soda straws have been spiral wound, phenolic saturated canvas is wound on mandrels and cured to make bearings, rubber has been saturated into cloth and wound spirally to make industrial hose and in recent years fiberglass saturated with polyesters have been wound into industrial pipe and other shapes.
Polyester fabrications have contributed most of the prior filament winding technology. Polyesters are syrups at room temperature and must be catalized and heated for rapid cure. Syrups are either saturated into fiberglass strands before, during or after winding of same. In all cases the glass is wound against glass because the syrup is too thin to effectively separate a tension wound strand of fibrous glass. Rotation of mandrel or form must be slow when using liquid polyester saturants to avoid centrifugal losses. The alternate method of post-saturation results in pinholes and porosity unless overwrapped with cellophane or equivalent and centrifugally spun to more effectively displace air.
Rotating conveying mandrels using belts, chain or other devices to continuously propel a builtup winding on the mandrel are known. Such require protective continuous overwrapping to prevent fouling of equipment with polyester syrup which effectively destroys the usefulness of the equipment. Such means of conveying and overwrapping layers also prevents efficient heat transfer from mandrel to wound part and thereby prevents such processes from being commercially competitive.
Polyester winding methods also include use of creels rotating about the mandrel. Balancing same at high speeds is impractical because reinforcement packages are not commercially uniform enough to be rotated on a creel at several hundred revolutions per minute.
All objects which can be made by winding have specific strength needs which require great winding pattern flexibility and reliability of pattern once established. Many continuous processes only provide for winding spirals. Pressure pipe and stressed products require that crossed spirals be used and same must usually be balanced.
To present date, to the applicant's knowledge, no thermoset plastic material capable of forming an unreinforced self-supporting strand is known to the trade.
Thermoplastics can form self-supporting strands, yet because of their inherent hot tack and other properties which make guiding and handling of strands difficult, have not been effectively used in filament winding. Because of the kinetic mode of operation needed in working with thermoplastics, an entirely different technique and art is required as compared with reinforced thermoset technology.
In prior commercial art, only one method has been found and it used no guiding or tension control when a rotating tank form mounted on a rail car was slowly moved past the ribbon die of an extruder to slowly produce a heavy overlapped spiral winding.
The technology of thermoplastic filament winding has substantially no background.
DEFINITIONS OF TERMS AS USED IN THIS INVENTION
The term thermoplastic as used herein comprehends thermoplastic resins (e.g., polystyrene, polyvinyl chloride) as well as other materials which soften even temporarily upon heating (e.g., B stage phenolic, epoxy and melamine resins as well as a variety of rubbers and organic or inorganic glasses).
The term strand is used in this application to mean a continuous guidable form of material usually supplied by extrusion and delivered to the guiding means in a molten condition which may be applied at one guiding and application station. Thus a strand may include a single filament or a warp of very many separate and parallel filaments. A filament may consist of a monofilament or a plurality of monofilaments, a plastic encased wire or a saturated reinforcement, a filled or hollow tube, a ribbon, an extruded profile, a length of foam, or any substantially continuous guidable form suited to wrapping on a mandrel regardless of how formed.
As herein used, guidable refers to its common meaning imparting requisite flexibility plus the ability of responding to surface treatments for rendering soft, tacky thermoplastics non-clinging to guides.
Stretch orientation is a term common to the textile fibers and plastic strapping manufacturing art. It refers to the orienting of composing molecules into a lateral alignment with attendant increase in tensile strength of the formed filament. The drawing and drafting of thermoplastics are coming to mean stretch orienting.
As herein used, case harden refers to a momentary, shallow, surface quenching such as is obtained by high speed passage through hot water or steam or momentary contact with a vaporizable film to impart a temporary non-sticky surface to a filament so that internal heat can later resoften it.
The term composite has recently come to mean a structure composed of fiberglass and plastic. The term heterogeneous is used in this application to cover the assorted combinations of materials other than fiberglass reinforced plastics.
Cohesion is the joining of similar material as contrasted to the adhesion of different materials.
The term turn-around node refers to the location at which the spiral of grouped separate parallel filaments reverses direction or the spiral turns around, a terminus.
Progressive winding as herein used refers to the pattern obtained when moving a strand guiding applicator to-and-fro while moving the applicator support base in a direction parallel to the axis of rotation of the part being formed. Thus increments or right and left turning spirals are formed with a degree of overlapping determined by the specific settings selected. A series of overlapping frustrums of cones comprises the layer formed from low lead movement of the applicator while open structures may be obtained with synchronized high lead patterns.
A slip mandrel is a rotating highly polished form usually tapered toward an unsupported or open end.
A troweling head is an applicator or delivery head for thermoplastic material, usually movable, and supplied with thermoplastic by, or flexibly connected to, a pressure supply such as an extruder, and having a doctor blade of any configuration which shapes, separates, meters, levels and compacts or trowels the applied material into intimate contact with the rotating mandrel or prior applied material on the mandrel. The bare mandrel and/or the pre-wrapped mandrel forms at least part of the outlet of the troweling head so that the applied material need not form a discrete self supporting strand.
The strand from a troweling head always escapes in the outwardly rotating direction, while the inward rotation of the mandrel prevents material escape on that side of the trowling head.
The terms incremental and sequential removal as well as intermittent removal mean that a movement of the formed product axially along the mandrel is synchronized with the transverse of the strand application means which applies the first hot layer to the cooling mandrel.
SUMMARY OF THE INVENTION
This invention relates in general to the production of pipe, tanks or other wound structures by winding hot, sticky strands of a thermoplastic material on a rotating mandrel.
A thermoplastic material is formed into pipe or similar articles by winding strands comprised of semi-hardened thermoplastic material on a rotating mandrel to form a layer thereon. In most instances, the winding is effected by an applicator which reciprocates in close proximity to the mandrel. In some cases, the mandrel is also reciprocated to provide an extended cooling period. The hardened pipe may be pulled or pushed from the mandrel in a continuous or intermittent fashion by conveying tractors and thereafter cut into sections as desired. The surface of the mandrel may be tapered to a small degree to aid in the removal of the pipe.
The handling of the hot thermoplastic strands can be accomplished through the use of guiding devices having means to partially cool the surface of the strand. The strand may also be temporarily case hardened by superficially cooling or dusted with thermoplastic powder to obtain handling capabilities.
By appropriate control of the rotational and reciprocatory speeds of the mandrel and the reciprocatory speeds of the applicator, pipe may be produced with specific strength characteristics.
An applied strand may actually consist of a guidable ribbon or a warp of parallel ribbons, filaments, tubes, rods, wires etc. in any combination or form of thermoplastic or thermoplastic clad continuous guidable shapes. The geometry of strand guiding, tensioning or forming apparatus may vary according to the needs of strand components used for a given product.
More specifically the invention involves use of a mandrel on which the product is wound is tapered and polished to facilitate removal of any chilled tubular shape formed thereon and has internal channels through which cold water or other chilling fluid is pumped to at least partly solidify the newly formed pipe so that it may be pulled or pushed from the mandrel.
In order to provide more time for the innermost layer of thermoplastic in contact with the mandrel to cool, the rotating chilled mandrel is allowed to remain in a stationary relationship with respect to the freshly applied material for at least an instant before moving the wound material axially along the mandrel. During such stationary period the winding operation is continued and overwraps the previously applied material.
Various tensioning and guiding devices are also provided for control of the hot strand between the extruder die and the applicator wand. The surface of these devices may be constantly supplied with water or other volatile liquid so that the strand passing over them does not stick or clog up the device. The strand may alternately be passed through a hot water bath at high speed to case harden it and solidify its skin prior to passing over guiding rollers. However, this case hardening is remelted by the internal heat or the strand soon after it emerges from the bath. Instead, the strand may be dusted with a compatible thermoplastic powder to enable a guide or roller to be used without a sticking problem. This dust or powder also melts soon after its application and thereby does not interfere with the bonding of adjacent windings and layers.
In a representative form of this invention, a thermoplastic strand is supplied in a hot semi-molten form from a conventional extruder. The strand is passed through tensioning devices which stretch it before it is applied by a rapidly reciprocating applicator wand to the rotating mandrel. Compacting or holding rolls are used to hold the new windings in place especially at the point where the wand changes direction. In some instances, the chilled mandrel is slowly traversed back and forth to increase the amount of time the newly formed pipe has to harden before being conveyed off. The pipe conveyors may be either continuous in operation or may intermittently strip the mandrel. Either internal or external rotating and gripping conveyors or tractors may be used. By closely synchronizing the rotation and traversing of the mandrel, the speed, length of stroke, and movement of the applicator wand and the movement of the conveyors, pipe with a specific wall thickness, desired pattern of winding and strength characteristics may be formed.
A cool strand of thermoplastic may also be used for the winding process but must be heated before application. Creation of a cohesive bond between unmelted strands may be accomplished by a shaped and heated shoe over which the strand must pass. The shoe is also in contact with the previous winding upon which the in-running strand is to be wound to assure its susceptibility to being bonded with the new winding. Alternately the rapidly moving strand may pass through a hot gaseous heat source, such as a flame, immediately prior to pressing against the body being wound. This gaseous heat source can also heat the surface of the body on which the in-running strand is being wound to effect superficial but intimate cohesive anchoring of the strand without melting or appreciably annealing a stretch oriented strand being applied. An oven may be used to encase a portion of the mandrel to stabilize and make uniform the temperature of the wound strands where slow exterior cooling is beneficial during progressive winding.
A variety of heterogeneous products may be formed by using a plurality of application stations either axially or circumferentially arranged in close proximity to the mandrel. Such multi-station apparatus may utilize an inner wound layer and an outer wound layer between which is sandwiched a layer of troweled on thermoplastic or thermosetting plastic. Pipe so formed can utilize the heat of the inner and outer thermoplastic windings to cure a middle layer of thermoset. The heterogeneous wall structure thus formed may take advantage of the strong points of several plastics, rather than depending on a plastic which is only good in a single respect. Thus this process may be used to make assorted products. For example, a series of products may be made by either winding a given material to form a single layered product or by winding successive layers of the same material in order to facilitate partial cooling of each layer or by winding a first layer in an annealed more resistant form, successive layers in a stress oriented high tensile form and finally an outer protective layer in less easily abraded annealed form. By these and other variations heterogeneous structures may be made from a single material applied in different forms or patterns.
In addition this process permits use of many combinations of materials and heterogeneous structures of great variety are possible. For example, pipe made from a first chemically resisting impervious inner layer overwrapped by one or more structurally strong layers and finally followed by outer layers as may be made from insulating foams and/or weather or flame proofing materials.
Furthermore, wound combinations may be made of thermoplastic materials containing reinforcements or encasements of any type such as: metal wire, textile or fiberglass threads or rovings, twine or mats, hollow, electrically conductive, or otherwise functional thermoplastic encasable strandforming materials.
Hollow structures such as pipe may also be wound from strands of fiberglass or like reinforcing material which have been saturated with or embedded in an encasement of thermoplastic which, when hot wound, serves as the structure bonding matrix. Adjustable tensioning devices may be used to prevent the filaments from cutting through the thermoplastic coating. Applicator units may also carry a non-adhering compacting roll as is needed to calender the hot applied strand into intimate contact with the mandrel or prior applied layers.
One preferred combination of materials is obtained by winding a first layer of hot thermoplastic material, a second layer of reinforced thermosetting material and a third layer of hot thermoplastic material to encase and supply added heat for curing the intermediate thermosetting layer as well as adding chemical, scuff and weathering resistance.
BRIEF DESCRIPTION OF THE DRAWINGS
The accompanying drawings illustrate the invention. In these drawings:
FIG. 1 is a plan view showing a portion of filament winding apparatus;
FIG. 2 is a plan view of an adjacent portion of the apparatus shown in FIG. 1.
FIG. 3 is a plan view of the remaining portion of the apparatus shown in FIGS. 1 and 2;
FIG. 4 is an enlarged plan view of one of the pulling tractors shown in FIG. 3;
FIG. 5 is a section on the line 5--5 of FIG. 4;
FIG. 6 is a plan view of a winding apparatus utilizing an internal gripper;
FIG. 7 is a fragmental section showing a collapsible mandrel;
FIG. 8 is a vertical section of a hot strand guiding device;
FIG. 9 is a vertical section of an alternative form of guiding device;
FIG. 10 is a vertical section showing a third guiding device;
FIG. 11 is a section showing a fourth guiding device;
FIG. 12 is a section showing a heated shoe applicator head;
FIG. 13 is a section showing a hot gas applicator head;
FIG. 14 illustrates a strand tensioning device;
FIG. 15 is a plan view of a pipe winding apparatus;
FIG. 16 is section on the line 16--16 of FIG. 15; and
FIG. 17 is representation, partially diagrammatic, of a system for producing composite pipe.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIGS. 1 through 3 illustrate a machine for the winding of plastic pipe or tank shells. The machine comprises a head stock 10 which contains and supports a spindle 12. The spindle 12 is connected at its forward end to a tapered windng slip mandrel 14 by a quick change lock nut 16. The mandrel is highly polished and is tapered toward its forward unsupported end, preferably by one to two degrees, to facilitate the removal of pipe wound thereon and to compensate for shrinkage of the cooling pipe. The highly polished surface of the mandrel also facilitates this removal as well as providing a smooth finish to the inner surface of the product pipe thereby reducing the frictional losses effected in a liquid flowing through the finished pipe.
The spindle 12 and the connected mandrel 14 are rotated by means of a chain driven sprocket gear 18 mounted on the spindle to the rear of the headstock 10. The driving chain 20 is connected to one of a pair of sprocket gears 22 and 24 mounted on the end of a drive shaft 26 which supplies a rotatory drive for the tractors 28 and 30 which are synchronized to continuously rotate with, and to remove finished pipe from the mandrel. The drive shaft 26 is supported in and by bearing blocks 32 and 34. Rotational power is supplied to the main tractor pull off drive shaft 40 through a timing chain 44 from the main drive shaft 26. The tractors 28 and 30, shown in more detail in FIGS. 4 and 5, are supported on the main tractor drive shaft 40 and two matched lead screws 46 and 48 which supply the power for the tractor to pull pipe from the mandrel. Lead screws 46 and 48 are driven through a transmission 42 and timing chains 50 and 52 from the main spindle drive shaft 26.
The tractors 28 and 30 are shown in more detail in FIGS. 4 and 5. The function of these tractors is to continuously remove completed pipe 54 from the mandrel 14. Each of the tractors has an air operated double chuck 56 which is clamped on the newly formed pipe 54 to pull it from the mandrel. The chuck 56 is rotated at the same speed as the mandrel 14 by a chain 60 driven from a sprocket gear 62. This gear 62 is slidably keyed to the main tractor drive shaft 40 so that the shaft 40 rotates the gear yet allows it to move longitudinally within a keyed slot in the shaft. It is important that the air chucks 56 be rotated at exactly the same speed as the mandrel to avoid applying a torque or twist to tne new pipe.
The pulling movement of the tractors 28 and 30 is controlled by the engagement of two half-nuts 66 and 68 with the lead screws 46 and 48 respectively. Each of these half-nuts 66 and 68 is controlled by a rectractable arm 70 and 72 in which they are carried. The upper ends of these arms 70 and 72 are rotatably connected to the ends of a piston in an air cylinder 78. When the piston in this air cylinder 78 is extended, the arms 74 and 76 rotate about the lower ends 80 and 82 so that the two half-nuts 66 and 68 engage the leads 46 and 48. Conversely, the half-nuts 66 and 68 are disengaged from the lead screws when the piston in the air cylinder 78 is retracted.
The clamping of the air chucks and the engagement of the half-nuts are controlled by means of uni-directional limit switches which are depressed by extending members on the tractors 28 and 30 as the members pass over them. The arrows in FIG. 3 adjacent these switches signify which direction the respective tractor must be traveling to actuate each switch. Each tractor 28 and 30 has two pairs of these controlling limit switches associated with it. The inner two switches 84 and 86 control the clamping and unclamping respectively of the air chuck; the outer two switches 88 and 90 control the engagement and dis-enagagement, respectively, of the half-nuts. The half-nut disengaging switch 90 also controls an air solenoid 92 which rapidly moves the tractor back toward the mandrel until it has passed over the air chuck clamping switch 84 and has actuated the half-nut engagement switch 88. The latter switch 88 also de-energizes the return air solenoid 92.
Preferably, one tractor has its air chuck clamped and is pulling the pipe as the other tractor is being returned to its starting position by the particular return air cylinder 92. The air chuck clamping switch 84 is activated only when the tractor is moving in a pulling direction, i.e., from left to right as in FIG. 3, and the air chuck unclamping switch 86 is activated before the return switch 90 so that the air chuck is clamped after and prior to any changes in the direction of the tractor's movement.
The actual winding of the pipe takes place in a zone defined by two holding rollers 100 and 102 located in close proximity to the mandrel 14. The thermoplastic ribbon or filament to be wound into pipe is supplied by a conventional extruder and its tension adjusted by tensioning devices before passing across an applicator wand 106 and being applied to the rotating mandrel 14. The wand 104 is connected to adjustable linkage 106 which has a finger 108 attached thereto which acts as the follower in the track of a cam 110. The configuration of this track controls the reciprocatory movements of the wand 104. It is to be understood that the track in this cam 110 shown in FIG. 2 is only exemplary of an actual cam track configuration. The actual configuration depends upon the lead of the winding desired. A long lead (i.e., a coarse thread) with respect to the turning mandrel, would create a pipe with generally longitudinal windings having a high beam strength; a short lead (i.e., a fine thread) would result in a pipe with high bursting strength. The cam configuration and rotational speeds are mandated by the specific pipe requirements.
The cam 110 is rotated through an adjustable transmission 111 from a driving chain 105 which permits the stroke speed of the wand 104 relative to the speed of mandrel to be adjusted for various types of pipe.
The continuous removal of pipe from the mandrel requires that the mandrel also reciprocate in exact timed relation with the applicator wand 104. An arcuate shifting fork 114 is positioned between the flanges 116 of a shift-collar member 118 fixed to the rear of the spindle 12 to effect this reciprocation. A finger 112 is at the lower end of the fork 114 which is operatively positioned in the trace of a second cam 115. This cam 115 is driven through a transmission 120 by the timing chain 105. The contour of the fork 115 permits the collar 118 to turn with the spindle, yet, under the direction of the cam 115, apply force to an appropriate flange 116 of the collar 118 thereby reciprocating the spindle.
The pipe wrapping process is begun by placing a thin cardboard tube or the like over the mandrel 14 and extending its forward end into the tractor pullers 28 and 30. Initially, the mandrel 14 and the applicator wand 104 are in their left-most positions. The end of a hot, tacky ribbon 11 of thermoplastic is placed directly into the in-running nip between the cardboard covered mandrel and the holding roller 100 nearest the headstock. The ribbon 11 may be either completely thermoplastic or may contain generally parallel reinforcing fibers which have been saturated with molten thermoplastic.
The first layer of pipe winding is placed on the cardboard covered mandrel as the application wand 104 is moved away from the headstock under the direction of its guiding barrel cam 110. The pitch of the winding is a function of the lead of the applicator wand 104 with respect to the rotational speed of the mandrel. The action of the holding roller 100 permits as large or as small a pitch as desired with minimal danger of the wound strands slipping. The second holding roller 102 is located at the other end of the transverse stroke of the applicator wand 104 to securely hold the winding in place as the direction of the applicator wand 104 is again quickly reversed by its barrel cam 110. The second layer may be reversed spiral with respect to the first and may either be at a different pitch or at the same pitch. These rolls 100 and 102 may be sprayed with a fog as a precaution against the strand sticking to them. Their use is particularly advantageous when the strand is composed of separate reinforcing filaments because the filaments are free to shift relative to one another as they are gripped by the rollers thereby preventing buckling of the strand of the "turn-around" node.
The movement of the mandrel under the control of its barrel cam 115 is synchronized with the reciprocating feed wand 104 and pull-off tractors 28 and 30 so that the mandrel advances by an amount preferably equal to the length of pipe pulled off by the tractors 28 and 30 for each complete cycle of the feed wand. The gradual advancement of the mandrel permits the just applied windings to be hardened by a chilling fluid running through internal cavities just below the surface of the mandrel, so that the mandrel may be slipped back to its starting position. The cooling fluid is supplied by a rotary fitting 122 which is carried on and reciprocates with the forward end of the spindle. The mandrel is quickly retracted by its cam at the end of its forward cooling stroke. Means for continuation of cooling the formed parts after removal from the mandrel are schematically indicated.
The initial windings of the pipe adhere to the cardboard tube starter permitting the tractors 28 and 30 to begin their continuous removal of pipe. Once the cardboard tube is gone the windings are applied directly to the polished and chilled mandrel. In addition, the newly formed pipe may pass through a chilling fog or bath 123 before being gripped by the tractors. The plastic covered cardboard starting tube may be discarded when the ends of the finished pipe are trimmed. The trimming and length cutter (not shown) may be located after the tractors.
The nodes formed when the holding rollers 100 and 102 retain the new winding as the direction of the feed wand 104 reverses must not be permitted to fall in the same circumferential position each time if it is desired to avoid a ridge in the pipe structure. The rotational speed of the mandrel, the movement of the mandrel and the wand stroke may be precisely adjusted to give a desired node pattern. The mandrel rotation and node precessing may be adjusted to give a straight single line, two or more lines, spiral lines, or a lost pattern with nodes not readily visible.
There are, of course, various modifications of this process which may be made within the scope of my invention. An additional roller 124 or sets of rollers located about the periphery of the mandrel, may be used to calender the newly formed pipe before it leaves the mandrel or to imprint, emboss or shape the pipe while yet soft with a trademark (or locally applied threads) for example.
Application of finishing, calendering, embossing and the like designs to the yet hot outer layer are considered part of my preferred process.
The rotary fitting 122 may be used to supply the mandrel with curing heat to permit the use of this system with thermosets. In this instance the bath 123 would be replaced by a curing oven and a release pre-wrap would be needed.
Another arrangement for forming plastic pipe in accordance with my invention is shown in FIG. 6. This structure comprises a tapered mandrel 132 which is connected to a rotating, non-reciprocatory spindle 130. The taper of the mandrel 132 is preferably about 1/2° to 2° to facilitate pipe removal by an internal gripper 134. This gripper, or tractor member, is rotated by a tubular shaft 136 at the same speed at which the mandrel 132 rotates. The tubular shaft 136 extends through a longitudinal bore in the mandrel and spindle through spacing collar 137 and is connected at its rear end to a flanged collar 138. A directional member 140 is arcuately forked at one end. This end fits in and about the collar 138. The other end of the forked member 140 forms a follower for a barrel cam 142. Rotary drive for the cam 142 is provided through an adjustable transmission 144 from a main spindle drive 146. The ends of the track in the cam 142 are flat to enable an air cylinder 148 supplied through a valve 150 from an air supply 152 to engage and disengage the gripper 134 when the gripper is not moving as determined by the positions of two switches 154 and 156.
More specifically, the gripper 134 is comprised of two compressing end members 158 and 160 which are connected at either end of a compressible rubber plug 162. A shaft 164 passes through the end member 158 closest to the mandrel, through the rubber plug 162 and is connected to the interior side of the other end member 160. The shaft 164 extends rearwardly through the hollow driving shaft 136 and terminates in a piston in the air cylinder 148. The air cylinder 148, when actuated, causes the shaft 164 to move longitudinally within, and with respect to, the encompassing shaft 136. The action compresses the rubber plug 162 causing its outer surface to radially expand and to come in contact with the inner surface of the newly formed pipe.
Thermoplastic strand is wound on the mandrel 132 using a cam guided wand apparatus generally the same as that shown in FIG. 1. A cardboard tube is placed initially around the mandrel and extends over the gripper 134. Tape is first wound on the tube covering the mandrel as the gripper 134 begins its reciprocating movement under the direction of the barrel cam 142. The inside of the mandrel 132 is provided with a plurality of chilling fluid channels to chill the surface of the mandrel in order to assure quick setting of the internal layers of the new pipe. The chilling liquid enters and leaves the spindle and mandrel through a rotary fitting 168 which rides on the tubular shaft 136 between the sheave member 138 and the rear spindle mounting block 170. The hardening thereby given to the interior surface of the pipe is sufficient to keep the compressed rubber plug 162 from deforming the pipe during conveyance. The cardboard tube has no further purpose after its rearwardly extending end is conveyed past the stroke of the gripper 134. It may be trimmed off and discarded after the desired length of pipe has been formed.
The intermittent operation of the system of FIG. 6 is preferably synchronized by appropriate relation of the cam 142 and gripping conveyor 134 movements to permit one stroke of the conveyor to expose an amount of bare mandrel equal to about one width of the strand being wound. This relationship gives a shingle or stepped relationship to the resultant layers of winding which effects high structural integrity in the wound article.
Apparatus and guides for handling and applying hot thermoplastic strands are shown in FIGS. 8 through 11. These structures are used to guide the hot sticky strand between a thermoplastic extruder and the winding mandrel and may be connected to auxiliary platforms adjustably positioned at appropriate places along the length of the guided strand. The device illustrated in FIG. 8 uses a wetted roller 196 which is rotated on an axis generally perpendicular to the path of the heated strand 198. This roller 196 is continually rotated and doctored to coat its surface with a film of water from a water bath 200. Steam is generated at the surface of contact between the top of the wetted roller 196 and the hot strand 198 which prevents the strand from sticking to the roller yet permits the roller to perform its function of guiding and supporting the strand. More specifically, the steam generated buoys up the strand and holds it off the surface of the roll.
The structure illustrated in FIG. 9 utilizes a nozzle 202 to spray steam or other fog at the line of intersection between a hot strand of thermoplastic 204 and a rotating roller 206. Again, this strand is buoyed up and rides on a steam layer.
A third structure is shown in FIG. 10 utilizing a sintered roll 208 which is supplied with steam or other cooling fog through a central journal 210. The steam escapes through the porous surface of the roll 208 and supports a hot strand 212 being guided by the roll 208 in a non-sticking relationship.
A similar structure is illustrated in FIG. 11 wherein a hot strand 216 passes over a non-rotating block 218 comprised of a sintered material. This block is supplied with a cooling fog, preferably steam, through an inlet 220. The configuration of the block 218 may be used to give more control and guidance to the strand for particular applications.
A relatively cold strand of thermoplastic may be used for winding but its surface must be heated to a sticky consistency before application to a mandrel or to windings already on a mandrel. Apparatus for this procedure are shown in FIGS. 12 and 13. FIG. 12 shows a strand 222 passing over a guide 224 and heated shoe 226. The heated shoe 226 is maintained at an elevated temperature by hot gas which is supplied through an inlet 228 generally parallel to the winding mandrel 230. The shape and heated surfaces of the shoe 226 enables both the surface of the in-running strand 222 and the surface of that portion of winding 232 already on the mandrel to be heated to a semi-molten consistency. In most instances, the tension on the in-running strand 222 is sufficient along with the applied heat to bond the progressive windings together. The carrier 234 for the heating element 226 may be retracted or pushed back on a slide 236 as wall thickness of the pipe being wound increases.
The structure of FIG. 13 also utilizes the concept of heating an in-running strand 238 at its point, or line, of intersection with already-laid-down windings. The relatively cool strand 238 passes over a guide 240 similar to that in FIG. 12, and is subsequently wound on a mandrel 242. A shaped nozzle 244 that is supplied with hot air or other gas and is directed at the place where the strand 238 touches the winding on the mandrel. Again the guide 240 carrying the nozzle 244 may be operatively moved away from the mandrel on a slide 246 as the pipe 248 increases in wall thickness.
In winding stretch oriented preformed material on a cold mandrel, heating the side which will be applied to the mandrel is only necessary to give the inner surface of such formed tubular article a highly glossy finish. Surface reheat means indicated are only needed where windings are applied over other windings and where windings overlap adjacent layers.
Apparatus, such as that shown in FIG. 14, is necessary in winding pipe which requires a close maintenance of the tension in the incoming ribbon. The control of the tension becomes very important when the ribbon contains reinforcing strands of a material such as fiberglass. If the tension on the winding is too great the fiberglass reinforcing strands (if continuous) will cut through the soft thermoplastic and the inner surface of the wound pipe will be what is known as glass rich which thereby greatly reduces the inner chemical resistance of the pipe or tank. The apparatus in FIG. 14 comprises a lower arm 256 and roller 257 which is rotatably and spring connected to a platform 258. An upper arm 260 which supports a roller 261 at one end is rotatably attached at its other, or lower end to the lower arm 256 by a pin or similar coupling 262. The rolls may be fogged to prevent sticking of the guided strand. To begin winding, a spring 264 which is connected between the upper and lower arm is disconnected to permit the upper arm 260 to be swung back into the dotted line position. The winding on the mandrel 266 is started by passing the starting end of a hot strand 268 over the roller 261 on the end of the retracted arm 260 and into the in-running nip between the roller 257, on the forward end of the lower arm 256, and the mandrel 266. The mandrel 266 is slowly rotated. The upper arm 260 is concurrently returned to its solid line position and the spring 264 reattached. The rolls 257 and 261, which are driven at an adjustable speed with respect to the mandrel, are used to exert tension on the incoming strand 268 to enable the strand to be wound on the mandrel with a constant winding tension: i.e., they isolate the winding process from changes in the tension of the supplied strand. Furthermore, the rolls 257 and 261 compact the incoming strand between them to assure uniformity of the strand thickness prior to winding. Similarly, the lower roll may compact the strand onto the mandrel or a layer of winding on the mandrel.
The pressure applied by these rolls is determined by the selection of the tension springs 264 and 265. The latter spring operatively connects the lower arm 256 to the base 258 of the device. The rolls may be grooved to avoid calendering adjacent separate reinforcing filaments together when several such filaments are used. The entire tensioning device shown in FIG. 14 rides on a transverse slide (not shown) which may be driven by a ball nut and screw or other similar means.
An apparatus for winding comparatively short lengths of pipe in accordance with my invention is shown in FIG. 15 and FIG. 16. The apparatus shown comprises a melted thermoplastic supply hopper 290, an extruder 292, an extruder driving motor 293 and a swiveling die head 294. The die head alternatively may be equipped as a saturating cross head for treating or saturating reinforcing filaments or rovings which would be supplied from a creel (not shown). Thermoplastic forced into the die head 294 by the action of the screw in the extruder 292 merges from the head as a ribbon 296. The ribbon passes into a tank 300 of hot water and under a roller 298 which is immersed in the tank. The water case hardens the strand enabling it to pass over subsequent guiding rolls 302, 304 and 306 without sticking. The still hot interior of the strand reheats the surface layers before the strand is wound on a rotating mandrel 308. The strand is guided onto the mandrel 308 by a traversing guide 310 which is driven back and forth on a lead screw 312. The rotary drive for the mandrel 308 and the lead screw 312 is contained in a head stock 314. The other end of the mandrel 308 is rotatably held in place by an adjustable center 316.
The other end of the lead screw 312 is supported and contained in a control box 318 which supports the adjustable center 320. This box 318 contains a revolution counter for the lead screw for adjustably effecting a reversal of the direction of rotation of the screw. The point of this reversal depends on the length of pipe being wound.
The length of the guiding mechanism for the hot strand between the die head 294 and the traversing guide 310 must be compensated as the mechanism swings through its winding application arc. Supporting side members 320 and 322 are rotatably connected to the traversing guide 310, to the front of the extruder supported water tank 300 and to each other. The common connection is by and on the shaft 324 which carries the middle roller 304. This roller 304 is moved up and down by the members 320 and 322 as the guide 310 is traversed back and forth in order to compensate for the change in length required in the mechanism arm.
FIG. 7 illustrates an easily removable, semi-collapsible mandrel for use in making short lengths of pipe where apparatus for conveying the pipe off is not practical. Th mandrel comprises a body portion 180 which is threaded at one end 182 for mounting in a driving spindle. A cylindrical collar 184 is fastened around the body of the mandrel 180 near one end. A low durometer rubber sleeve 186 is slipped on the mandrel and into abutting relationship with the collar 184. A second collar 188 is mounted as by threads 190 on the opposite end of the mandrel into abutting relation with the other end of the rubber sleeve 186. A thin jacket 192 preferably made from a material such as Teflon or silicone rubber, is fastened to the exterior surface of the rubber sleeve 186. The thread-on collar 188 is tightened in order to compress the rubber sleeve 186 and force the jacket 192 uniformly and radially outward. This expansion of the jacket 192 can be effected prior to or after connecting the mandrel 180 to a spindle. After thermoplastic pipe of the desired thickness and length has been wound on the mandrel, the mandrel may be removed from the spindle and another like mandrel installed. To remove the pipe, the compressing collar 188 is loosened thereby permitting the rubber sleeve 186 to return to its original shape which in turn permits the mandrel to be easily extracted.
Collapsing and expanding of such a special release mandrel can also be mechanically synchronized with the already described collapsing and expanding incremental intermittent pushoff device 134 already described and shown in FIG. 6.
An oven structure 326 is optional and when used may partially surround the mandrel 308 as shown in FIG. 15 and FIG. 16. It is comprised of an outer hood 328 and an array of low intensity flame burners or hot gas inlets 330. The oven maintains the surfaces of the partially complete pipe in a semi-molten stage to assure the bonding of subsequent layers.
Using the mandrel illustrated in FIG. 7 with the process diagrammed in FIGS. 15 and 16 and the guiding and tension controls previously described, parts such as posts, poles and other assorted tubular shapes can be made. When the traverse lead is reversed at the same node each pass of a full length oven enclosed wind and when the lead is substantially greater than the width of the strand being applied, on open meshed product of great strength-to-weight ratio is obtained.
In a similar process use of an oven may be avoided by progressively winding a mandrel with an open meshed pattern where the applied wrap encases the prior layer before cooling and shrinking can distort or weaken the part.
A structure for forming a heterogeneous pipe is shown in FIG. 17. It is generally of a mandrel 332 mounted on and driven through a transmission in a headstock 334.
A serial array of barrel cams 336, 338 and 340 are mounted on a shaft 342 which is driven by a timing chain 344 from the main mandrel drive in the headstock 334. The barrel cam 336 nearest the headstock controls the stroke of a hot thermoplastic strand applicator 346. The thermoplastic strand 347 is supplied directly from an extruder 348 for winding a first layer on the mandrel. Preferably, this first or inner layer is comprised of a highly chemical resistant thermoplastic such as polystyrene, or polyvinyl-chloride.
The second layer is comprised optionally for example either of a thermoplastic or a thermosetting plastic. In this instance, a troweling head 350 is guided by a barrel cam 338 for reciprocatory motion. A second extruder 351 supplies, in the case of thermoplastic, molten material through a flexible supply tube 352 which is encased in a low voltage braided resistance heater. The supply tube terminates in a trowling head 350 which extrudes and trowels a layer of hot plastic onto the first previously wound layer. Alternatively, the second layer may be comprised of a thermo-setting plastic such as a polyester, a polyvinyl-chloride plastisol containing a blowing agent or any other heat activated plastic material which can also be troweled on.
A third layer is applied by winding a hot thermoplastic strand by a third applicator wand 354 supplied with a strand 356 from an extruder 358. The third layer is generally comprised of a strong, scuff resistant substance such as a weatherproof grade of acrylic or an impact grade of polystyrene.
There are several permutations of this process which fall within the scope of my invention. If the middle layer were a thermo-setting plastic the hot third layer and the still semi-hot first layer would cause the setting of the sandwiched layer. This process enables pipe with a thermosetting layer to be manufactured without the need for reinforcing glass filaments which has heretofore characterized thermosetting plastic pipe. If the middle layer were made of PVC (polyvinyl-chloride) with a blowing or foaming agent, the hot third layer will seal the middle layer and cause the blowing agent to react. The resulting pipe would not only be chemical resistant on the inside and scuff resistant on the outside but would be insulated by the foamed middle layer. The middle layer could also be comprised of filamentary winding which under winding tension imbeds itself in the first layer of thermoplastic.
In any of the various filament or strand winding devices above described, the characteristics of the pipe formed will depend upon the type of plastic employed and upon the use to which the pipe is going to be put. A pipe with high beam strength requires relatively high lead winding helices, while high bursting strength requires very low lead helices. Combinations of patterns applied at successive stations give control of resultant properties.
The tight winding of hot strands inherently adds strength to the finished product by stretch orienting the molecular structure in the strand. The type of conveyance, i.e., internal or external grippers, depends upon the length of pipe which is desired. External grippers with their continuity of conveyance are much more adapted to use with long lengths of rigid pipe than are the intermittent working internal grippers which can work best in small diameter more flexible tubing.
While the winding machines illustrated are described as used in the production of pipe having circular cross-section and therefore employ mandrels of circular cross-section, mandrels of other cross-sectional shapes may be employed to produce pipes of other than circular cross-section.
Although one of the major embodiments of this process is elimination of the need for prewrapping of a complex self-conveying mandrel as is used with reinforced polyesters on occasion, e.g., as where a very low tensile first layer material is used, a prewrapping and/or application of mold release material to the subject tapered mandrel may be used.
The great variability of the claimed process may be further illustrated by using a more steeply tapering chilled mandrel, for example, a mandrel tapering from 12 inches to 6 inches over a length of 81/3 ft., and by controlling the lateral traverse movement of the base of the reciprocatable applicator station and further synchronizing the movement of the first hauloff tractor with the said base traverse (e.g., by mounting the tractor traverse controlling limit switches on a movable bar attachable to said base), the winding can be caused to take place at any part of the tapered mandrel and products may thereby be made having any inside diameter corresponding to that part of the bar where such winding is applied. In this specific instance the inside diameter of each stepwise incremental axial movement would have a taper of 0.030 inches per axial inch. Fairly rapid transitions in diameter give sculptured or turned columnar effects while a constant movement can produce uniformly tapered products such as light poles. The inside diameters will always have incremental tapers equal to the mandrel's taper.
Considerable variation is permissible in the relation between the width of the ribbon and the lead of its turns as wound. Successive turns may overlap to any desired extene by making the lead less than the width of the strand. If desired, the lead may be so selected that adjacent turns abut without any overlapping. If the lead is lengthened to a point where adjacent turns are axially spaced, an open-wound layer will be formed, and by superimposing a plurality of such layers it is possible to produce a hollow structure which, while not suitable for the conveyance of liquids, will serve, for example, as a flag pole. | A precision thermoplastic filament winding process for forming into pipe or similar articles by winding strands comprised of semi-hardened thermoplastic material on a rotating mandrel to form a layer thereon.
Single or multiple component, unreinforced and/or continuously reinforced filament wound cylindrical products are continuously produced by winding, at least an inner layer of thermoplastic material upon a rotating cooling mandrel which reciprocates axially in timed relation with moving guiding means and a rotary stripping means.
Timing sequence provides a dwell relationship between the cooling mandrel and the hot semi-molten applied material so that at least the inner surface of the freshly applied material is rendered non-sticking and strong enough to enable it to be moved along the surface of the mandrel an incremental distance determined by the planned sequence and pattern required to give the desired specific properties. | 1 |
CROSS-REFERENCE
The inventions disclosed and claimed in co-assigned U.S. patent applications Ser. No. 267,235, filed May 26, 1981, and Ser. No. 282,218, filed July 10, 1981, which may be material to the examination of this application, are incorporated herein by reference.
BACKGROUND OF THE INVENTION
Robots and the science of robotics are receiving increasing interest and attention both in terms of use in industrial environments and research to improve existing robots and develop far more sophisticated robots.
Robots of the current generation may be equipped with elementary artificial vision and tactile sensors, e.g., television cameras and pressure sensitive switches or load cells, respectively. The ability to accurately sense small variations in pressure, ideally on the scale exhibited by biological fingers, and utilize that information in an interactive or feedback system, is predicted to become an increasingly important area of robotic technology in the future.
SUMMARY OF THE INVENTION
The pressure imager of the invention consists of a plurality of sensing cells or regions arranged in an array or pattern in a body of semiconductor material, a layer of the oxide of the semiconductor material situated on and contiguous with a substantial portion of the top major surface of the body, and an adherent layer of piezo-electric material over the oxide layer. Preferably, the piezo-electric material is a flexible, compliant, and tough polymer such as polyvinylidene fluoride. The small size of the individual sensing regions yields a highly sensitive imager ideally suited for use in robotic architecture.
The individual sensing cells are of the piezo-electric gate controlled diode (PZGCD) type or the piezo-electric field effect transistor (PZFET) type selected primarily with reference to the operating environment. The PZGCDs are characterized by a small diameter substantially cylindrical hole which extends completely or substantially through the thickness of the body between the major top and bottom surfaces of the body and a substantially cylindrical semiconductor region of generally uniform cross-section which is substantially concentric with the hole and extends between the major surfaces. The conductivity type of the semiconductor region is made opposite to that of the body of semiconductor material, thus a substantially cylindrical P-N type junction extending between the major top and bottom surfaces of the body is formed with the body. The individual cells are separated by a gridwork of excavations in the top surface of the body or, preferably, by a gridwork of heavily doped regions extending a short distance into the interior of the body from the top major surface.
Cells having piezo-electric field effect transistors (PZFETs) are similar to cells having PZGCDs, except there are two spaced holes with their associated substantially concentric cylindrical semiconductor regions per cell.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevation view, schematic in form and in cross-section, of a portion of a robotic pressure imager of this invention with an object situated thereon.
FIG. 2 is an elevation view, schematic in form and in cross-section, of one of the sensing cells of the imager of FIG. 1 of the piezo-electric gate controlled diode type.
FIG. 2A is an elevation view, schematic in form and in cross-section, of the cell of FIG. 2 drawn to illustrate the principles of operation.
FIG. 3 is an elevation view, schematic in form and in cross-section, of one of the sensing cells of the imager of FIG. 1 of the piezo-electric field effect transistor type.
FIG. 4 is a bottom view, schematic in form, of a portion of the robotic pressure imager of FIG. 1 having sensing cells of the piezo-electric gate controlled diode type and means for addressing the diodes.
DETAILED DESCRIPTION OF THE INVENTION
With reference to FIG. 1, there is shown in schematic cross-section a portion of a robotic pressure imager 10 of the present invention. Illustratively, an object, i.e., bolt 5 whose size, shape, and weight are to be sensed, is shown situated on imager 10.
The principal elements of imager 10 are a plurality of sensing regions 20 situated in a pattern or array in a body 15 of semiconductor material, a layer 16 of the oxide of the semiconductor material covering at least a substantial portion of top surface 22 of body 15, and a layer 17 of piezo-electric material situated over and adherent to oxide layer 16. Sensing regions 20 are considerably smaller than the features of the object to be sensed, thus the imager of this invention has high sensitivity.
The semiconductor material of body 15 may be selected from those materials which are known by the practitioners of the art of the construction of semiconductor or microelectronic devices. Suitable materials include silicon, germanium, compounds of a group III element of the periodic table and a group V element (e.g., gallium arsenide) and compounds of a group II and a group VI element (e.g., cadmium telluride). Silicon is presently preferred due to its availability and the ease with which a passivating film, e.g., layer 16, may be formed. Body 15, and imager 10, are in the form of thin, i.e., on the order of about 6 to about 100 mils in thickness, wafers or chips whose shape is determined in accordance with the dictates of the particular robotic architecture with which imager 10 is to be used. The thickness dimension, measured as the perpendicular distance between top major surface 22 and bottom major surface 23, is, therefore, small in comparison to the lateral dimensions of top 22 and bottom 23 major surfaces of body 15.
Conventional piezo-electric materials, e.g., quartz, Rochelle salt, and lithium sulphate monohydrate (Li 2 SO 4 .H 2 O), can be used for layer 17. However, since the aforementioned conventional materials are typically hard, stiff and brittle, a preferred alternate is a thermoplastic fluorocarbon polymer such as polyvinylidene fluoride (PVF 2 ). These polymers are compliant, flexible, and tough and are available commercially as sheets as thin as 6 μm in rolls 1000 meters long and over 1 meter wide. Moreover, in such quantities, they are relatively inexpensive compared to the conventional piezo-electric materials. In addition, PVF 2 , like Teflon®, is chemically inert, electrically insulating, and has been used as a protective coating for metallic surfaces. These polymers can be easily applied as adherent layer 17 by the use of suitable adhesives, such as rubber cement or epoxy, or by heating to about 200° C., with pressure applied, for a time sufficient to render the polymer tacky and then cooling.
In FIG. 2, there is shown schematically in more detail a single sensing region or cell 20. Region 20 of FIG. 2 is a piezo-electric gate controlled diode (PZGCD) made in accordance with the method disclosed and claimed in the above-referenced Ser. No. 267,235 application. For purposes of illustration, the material of body 15 is silicon with a substantially uniform distribution of atoms of an impurity element, i.e., a dopant, therein. The concentration of the dopant atoms is typically measured in terms of the resistivity of body 15 and, if selected properly, will impart P-type or N-type conductivity to the silicon. As is known by the practitioners of the semiconductor arts, if the dopant atoms are Al, Ga or B, for example, the silicon will exhibit P-type conductivity and if the dopant atoms are As, Sb, or P, for example, the silicon will exhibit N-type conductivity. Illustratively, the silicon of body 15 of FIG. 2 is lightly doped, i.e., has a low concentration of impurity atoms and is of the N - type as indicated by the symbol N - . Body 15 is lightly doped so that its conductivity type may easily be inverted to the opposite type conductivity by the application of an electrostatic field as discussed further below.
Hole 21 is a cylindrical cavity extending substantially perpendicularly between major top 22 and bottom 23 surfaces of body 15 through the thickness dimension of body 15. Hole axis 24 is substantially parallel to substantially cylindrical inner surface 25 of hole 21.
Holes 21 are best produced by the laser drilling process disclosed in the cross-referenced Ser. No. 267,235 application. Briefly described, a laser such as ESI, Inc. Model 25 Laser Scribing System modified with a 10 watt (maximum) optoacoustic Q-switched Nd:YAG head manufactured by U.S. Laser Corp. is used. The laser is operated in a repetitively Q-switched mode with a focused beam size of about 20 microns, a depth of focus of about 250 microns, an individual pulse duration of about 200 nanoseconds and a repetition rate of about 3 KHz. At a power level of about 2 watts, measured independently in a continuously pulsed mode, ten pulse trains of 5 msec duration separated by a 10 msec delay drill approximately 5 holes per second. Using the above parameters, holes 21 as small as about 3/4 mil in diameter (D) with axis 24-to-axis 24 spacings as close as about 1.5D can be drilled through 12-mil thick silicon wafers by the laser beam means without spalling, cracking, or introducing stresses or strains, i.e., damage, into the material of semiconductor body 15 adjacent to holes 21.
Region 26 shown in FIG. 2 is a semiconductor region of generally uniform cross-section substantially concentric with hole 21 and extending between surfaces 22 and 23. Region 26 is made by diffusing impurity atoms radially a distance t into body 15 from surface 25 by gas diffusion or from an adherent solid state source in accordance with the method described in more detail in the cross-referenced Ser. No. 267,235 application. In the PZGCDs of this application, region 26 will have at least a different type conductivity from that of body 15.
Interface 27 formed between region 26 and the semiconductor material of body 15, is substantially concentric with hole 21, extends between surfaces 22 and 23, and is situated away from inner surface 25 by the distance, t, to which the impurity atoms diffuse into body 15 from surface 25. Since, as illustratively shown on FIG. 2, the material of body 15 is of N-type conductivity and region 26 is of P-type conductivity, interface 27 will be a P-N type junction.
Longitudinally-extending regions 28 serve to isolate adjacent sensing regions 20. Regions 28 may be excavations below surface 22, but, preferably, regions 28 are semiconductors having the same conductivity type as body 15, but are more heavily doped as indicated by the symbol N + . Doped isolation regions 28 may be formed by diffusing the dopant into body 15 or by ion implantation techniques conventionaly known to those skilled in the art of semiconductor device manufacture. Isolation regions 28 should extend at least about 2 microns into body 15 from surface 22. As noted above, the diameter, D, of hole 21 is typically 1 mil. The center line 24-to-center line 24 distance between adjacent cells 20 should be about 2D, thus regions 28 will be about 1 mil from center line 24. This spacing represents a good trade-off between cell resolution which is a measure of the size of the object which can be sensed and cell sensitivity which is a measure of the cell's ability to detect small changes in pressure per cell surface contact area.
After regions 28 are formed, layer 16 of the oxide of the material of body 15 is formed in contact with surface 22. Since the area of holes 21, as viewed looking down on surface 22, is small in comparison to the surface area of cell 20, as delineated by regions 28, substantialy all of the surface of cell 20 will be covered by oxide layer 16. Thereafter, layer 17 of the piezo-electric material, preferably PVF 2 , is affixed on top of layer 16 as discussed above. Layer 38, which is optional, is discussed in detail in a subsequent section below.
The operation of sensing region 20 is shown schematically in FIG. 2A whereon certain details of FIG. 2 have been omitted for clarity and others added to aid the following description. Any pressure, P, on PVF 2 film 17 generates a polarization, P Q , in film 17 that induces a charge, Q s , on surface 29 of the film in accordance with equations (1) and (2)
P.sub.Q =αP (1)
and
Q.sub.s =BP.sub.Q (2)
where α and β are material constants. As with any piezo-electric material, the application of stress generates an electrostatic charge within the material. The polarity of the charge, positive or negative, will be a function of the type of stress, e.g., tensile or compressive, and will either be unique to the material or, as with PVF 2 , may be imparted by manufacture.
Surface charge Q s of the proper polarity first causes a space-charge or depletion zone to form in near-surface region 30 and, with increasing pressure, the conductivity type of region 30 changes to the type opposite to that of the material of body 15, as shown in FIG. 2A. With further increases in pressure, region 30 is extended farther away from surface 22. While the pressure-induced changes in region 30 are small, they are much larger and more readily measured than the electrostatic charges in layer 17. Thus, the changes in region 30, including the formation of a depletion zone, may be accurately measured by means of suitable instrumentation, e.g., a capacitance bridge, connected between regions 26 and body 15.
In FIG. 3, there is shown schematically a single sensing region or cell 20 of the piezo-electric field effect transistor (PZFET) type. The nomenclature of FIG. 2 is carried over to FIG. 3 and is the same except as indicated in the following discussion.
Blind holes or cylindrical cavities 21 and 21A extending from bottom surface 23 into and terminating in the thickness dimension of semiconductor body 15 can reproducibly be made by carefully controlling the number of pulses from the above-described laser operated with the parameters described above. Blind holes are an alternative embodiment of the through-thickness holes shown in FIGS. 2 and 2A, thus the PZGCDs of FIGS. 2 and 2A and the PZFET of FIG. 3 may be made either with through-thickness holes or blind holes. With blind holes 21 and 21A, the dopant is diffused from inner walls 25 as well as from bottoms 33 of the holes to form semiconductor regions 26. Regions 26 will be substantially in the form of right circular cylinders if the cavities are laser drilled substantially completely through body 15, i.e., to within about 10% of the thickness dimension of body 15. In FIG. 3, for illustrative purposes, the conductivity type of body 15 and semiconductor regions 26 have been selected opposite to those shown in FIGS. 2 and 2A, and therefore, the polarity of layer 17 is also selected opposite to that of FIGS. 2 and 2A. As in the case of the PZGCD, the diameter of cavities 21 and 21A is about 1 mil. The center line 24-to-center line 24 distance, L, between holes 21 and 21A of one cell 20 is about 2D, or 2 mils, and the distance between the nearest cavities of adjacent cells 20 is also about 2D, thus regions 28 are approximately equidistant between center lines 24 of adjacent cells.
Pressure, P, is shown applied across the entire sensing surface 29 of cell 20, thus regions 30 extend out to regions 28 and a continous region 30 is formed between semiconductor regions 26 between holes 21 and 21A. Pressure, P, as sensed by PZFET cell 20 of FIG. 3 is best detected and measured in terms of resistance changes measured between semiconductor regions 26 surrounding holes 21 and 21A. Incremental increases in pressure, P, from that depicted in FIG. 3 drives regions 30 deeper into body 15 and produces a further incremental detectable change in resistance. For lighter pressures or pressures over a smaller area of surface 29 than is illustrated in FIG. 3, regions 30 will be less extensive and may not form a continuous region between semiconductor regions 26, however, a detectable change from the unstressed material will be produced.
The robotic pressure imager 10 of FIG. 1 consists of a plurality of cells 20 arranged in an array. By the term array it is meant that cells 20 are arranged in a periodic repeating geometric pattern. An example of an array is shown in FIG. 4 which is imager 10 of FIG. 1 when viewed by looking at a portion of bottom surface 23. Illustratively, individual cells 20 are of the piezo-electric gate controlled diode type shown in FIGS. 2 and 2A. Cells 20 are bounded by the gridwork formed by intersecting isolation regions 28. When viewed from top surface 22, isolation regions 28 are continuous between their points of intersection 38, but are shown as dotted lines in the bottom view of FIG. 4. The center lines of holes 21 are located at the orthogonal intersections of a first set of parallel lines 34 separated from each other by the distance M and a second set of parallel lines 35 separated from each other by the distance N which, in FIG. 4, is equal to M. Concentric with holes 21 are semiconducting regions 26 and interfaces 27.
The array of FIG. 4 is illustrative and is not intended to be limiting as other arrays compatible with the robotic functions to be performed are within the contemplation of the invention. For example, it may be advantageous for the array to consist of a grouping of a small number of cells in an array with the groupings themselves arranged in a larger array configuration, i.e., a hierarchy of arrays. Similarly, isolation regions 28 may be in a form other than the straight line segments of FIG. 4, e.g., a plurality of circles whose peripheries do or do not touch or intersect.
Further shown on FIG. 4 are means for obtaining the information from cells 20 of imager 10. A first series of parallel conductive strips 36 are placed in contact with or in the proximity of bottom surface 23, but in contact with semiconductor areas 26 using conventional semiconductor device manufacturing techniques. On upper surface 22, there is similarly provided in contact with the portions of semiconductor regions 26 accessible from top surface 22 a second series of parallel conductive strips 37 which are orthogonal to the first set. Microelectronic solid-state devices, for example, (not shown) may be provided to permit each cell 20 of imager 10 to be addressed individually.
The second set of semiconductor strips 37 may be provided on the same surface as first set 36 as is typical in the prior art. The uniqueness of through-thickness diodes 26, i.e., the combination of hole 21 plus semiconductor region 26, however, permits the conductive strips to be placed on opposite surfaces thus greatly reducing the potential for interference in the form of cross-talk which may arise in prior art devices. A protective covering layer (not shown) overlying bottom surface 23 may optionally be provided.
Use of the piezo-electric gate controlled diode (PZGCD) is generally preferred for cell 20 when imager 10 is used in the presence of floating potentials and in the presence of static electricity. In this type environment, it may be advantageous to place a grounded metal layer over piezo-electric layer 17 to shield imager 10 from stray charges. Such a grounded layer is shown schematically in FIG. 2 as layer 38. Layer 38 may be provided as a thin sheet applied over layer 17 or formed in place by such techniques as sputtering or evaporation of a metal such as aluminum. The thickness of layer 38 should be on the order of about 1 micron so as not to interfere with the ability of cells 20 to independently sense pressure changes. The piezo-electric field effect transistor (PZFET) is generally preferred for cell 20 when imager 10 is used in environments having alternating current (AC) type noise. Oxide layer 16 may also be considered optional with cells 20 and imager 10, however, use of layer 16 is preferable since it prevents the buildup of stray charges from impurity ions, for example, at top surface 22.
Those skilled in the art will readily recognize that other changes, omissions and additions from the form and detail of the preferred embodiments shown herein may be made without departing from the spirit and scope of the invention. | A fine-scale array of pressure transducers which mimic biological nerve endings and are particularly useful in robotic architecture are provided. | 7 |
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