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FIELD OF THE INVENTION
The invention is generally related to data processing, and in particular to processor architectures and execution units incorporated therein.
BACKGROUND OF THE INVENTION
The fundamental task of every computer processor is to execute computer programs. How a processor handles this task, and how computer programs must present themselves to a processor for execution, are governed by both the instruction set architecture (ISA) and the microarchitecture of the processor. An ISA is analogous to a programming model, and relates principally to how instructions in a computer program should be formatted in order to be properly decoded and executed by a processor, although an ISA may also specify other aspects of the processor, such as native data types, registers, addressing modes, memory architecture, interrupt and exception handling, and external I/O. The microarchitecture principally governs lower level details regarding how instructions are decoded and executed, including the constituent parts of the processor (e.g., the types of execution units such as fixed and floating point execution units) and how these interconnect and interoperate to implement the processor's architectural specification.
An ISA typically includes a specification of the format of each type of instruction that is capable of being executed by a particular processor design. Typically, an instruction will be encoded to include an opcode that identifies the type of instruction, as well as one or more operands that identify input and/or output data to be processed by the instruction. In many processor designs, for example Reduced Instruction Set Computer (RISC) and other load-store designs, data is principally manipulated within a set of general purpose registers (GPR's) (often referred to as a “register file”), with load and store instructions used to respectively retrieve input data into GPR's from memory and store result or output data from GPR's and back into memory. Thus, for a majority of the instructions that manipulate data, the instructions specify one or more input or source registers from which input data is retrieved, and an output or destination register to which result data is written.
Instructions are typically defined in an ISA to be a fixed size, e.g., 32 bits or 64 bits in width. While multiple 32 or 64-bit values may be used to specify an instruction, the use of multiple values is undesirable because the multiple values take more time to propagate through the processor and significantly increase design complexity. With these fixed instruction widths, only a limited number of bits are available for use as opcodes and operands.
Each unique instruction type conventionally requires a unique opcode, so, in order to support a greater number of instruction types (a continuing need in the industry), additional bits often must be allocated to the opcode portion of an instruction architecture. In some instances, opcodes may be broken into primary and secondary opcodes, with the primary opcode defining an instruction type and the secondary opcode defining a subtype for a particular instruction type; however, even when primary and secondary opcodes are used, both opcodes occupy bit positions in each instruction.
Likewise, a continuing need exists for expanding the number of registers supported by an ISA, since improvements in fabrication technology continue to enable greater numbers of registers to be architected into an integrated circuit, and in general performance improves as the number of registers increases.
Each register requires a unique identifier as well, so as the number of registers increases, the number of bit positions in each instruction required to identify all supported registers likewise increases.
As an example, consider a processor architecture that supports 32-bit instructions with 6-bit primary opcode fields, and thus supports a total of 64 types, or classes of instructions. If, for example, it is desirable to implement within this architecture a class of instructions that identifies up to three source registers and a separate destination register from a register file of 64 registers, each operand requires a 6-bit operand field. As such, 6 bits are needed for the primary opcode, 18 bits are needed for the source register addresses and 6 bits are needed for the target register address, leaving only 2 bits for an extended opcode, and allowing for only four possible instructions in this instruction class.
In most instances, however, more instruction types are needed for an architecture to be useful. For instance, an instruction class for performing floating point operations may need instruction types that perform addition, subtraction, multiplication, fused multiply-add operations, division, exponentiation, trigonometric operations, comparison operations, and others.
Conventional attempts have been made to address these limitations. For example, three-source operations may be made destructive, meaning the target and one source address would be implicitly equal, such that one address field in the above example would not be needed, freeing up space for additional extended opcodes. Destructive operations, however, are often not convenient for compilers and software engineers, because often times an extra copy of the source data that would be overwritten by the destructive operation needs to be saved away in a temporary register, which can have potential performance problems in addition to using valuable temporary register space.
Therefore, a significant need continues to exist in the art for a manner of increasing the number and complexity of instructions supported by an instruction set architecture.
SUMMARY OF THE INVENTION
The invention addresses these and other problems associated with the prior art by obtaining the most significant portion of the full register address from register address calculation logic, which obtains the most significant portion of the full register address from a least significant portion of the current instruction's instruction address, and concatenates this portion with a portion of the address contained in the instruction, yielding a full register address suitable for addressing data in a large register file. The method of obtaining the most significant portion of the register address from the least significant bits of the instruction address is used as a substitute for storing full register addresses in the instruction. This allows independent instructions to be nestled between dependent ones in the instruction stream without hampering performance and also allowing for optimal secondary opcode space in the instruction.
One major reason why instruction set architectures strive for large numbers of registers is so that loops can be “un-rolled” to minimize branch misprediction performance penalties. The large numbers of registers are needed to do spills and fills of data without reusing the same register in a loop. Consider the following example where a long Taylor series approximation is computed for sin(x) with many iterations:
sin
(
x
)
≈
x
-
x
3
3
!
+
x
5
5
!
-
x
7
7
!
+
x
9
9
!
-
x
11
11
!
+
x
13
13
!
-
x
15
15
!
# initially:
# f1, f2, f10 contain x
# f3, f4, f6, f8 contain 1.0
# f7 contains −1.0
loop:
fmul
f2, f1, f2
# f1 contains x, initially f2 contains x also
fmul
f2, f1, f2
# f2 now contains x raised to the desired exp
fadd
f3, f3, f6
# increment the counter, initially contains 1
fmul
f4, f3, f4
# f4 contains the running factorial, init 1
fadd
f3, f3, f6
# increment the counter
fmul
f4, f3, f4
# f4 contains the running factorial
fdiv
f5, f6, f4
# f5 now has the reciprocal of the factorial
fmul
f8, f7, f8
# flip the sign appropriately
fmul
f9, f5, f2
# multiply the reciprocal with the x
component
fmadd
f10, f9,
# correct the sign and add to the sum in f10
f8, f10
fcmp
f3, end
# compare counter (exponent) to end
blt
loop
# branch back to loop if f3 < end
After loop unrolling twice, the loop may be similar to the below code listing, where registers f1 through f10 are used for the most significant part of the approximation, and f11 thru f20 are used for the least significant (starts with the x13/13! term), and they are summed together at the end.
# initially:
# f1, f2, f10 contain x
# f3, f4, f6, f8 contain 1.0
# f7 contains −1.0
# f1, f2, f10 contain x
# f3, f4, f6, f8 contain 1.0
# f7 contains −1.0
# end contains 5
loop:
fmul
f2, f1, f2
# f1 contains x, initially f2 contains x also
fmul
f12, f11, f12
#
fmul
f2, f1, f2
# f2 now contains x raised to the desired
exp
fmul
f12, f11, f12
#
fadd
f3, f3, f6
# increment the counter, initially contains
1
fadd
f13, f13, f16
#
fmul
f4, f3, f4
# f4 contains the running factorial, init 1
fmul
f14, f13, f14
#
fadd
f3, f3, f6
# increment the counter
fadd
f13, f13, f16
#
fmul
f4, f3, f4
# f4 contains the running factorial
fmul
f14, f13, f14
#
fdiv
f5, f6, f4
# f5 now has the reciprocal of the factorial
fdiv
f15, f16, f14
#
fmul
f8, f7, f8
# flip the sign appropriately
fmul
f18, f17, f18
#
fmul
f9, f5, f2
# multiply the reciprocal with the x
component
fmul
f19, f15, f12
#
fmadd
f10, f9, f8,
# correct the sign and add to the sum
f10
in f10
fmadd
f20, f19, f18,
# correct the sign and add to the sum
f20
in f20
fcmp
f3, end
# compare counter (exponent) to end
blt
loop
# branch back to loop if f3 < end
fadd
f10, f10, f20
# sum
Note that to minimize branch mispredict penalties and for other performance reasons, this loop would be unrolled further than 2 times typically, but for brevity's sake the example shown above is only unrolled two times. Note that to unroll the loop 4 times, approximately 40 registers would be needed, and this surpasses the limit of 32 registers for many architectures. Notice also that the unrolled target registers and source registers follow a predictable pattern and are interleaved, where instructions calculating the most significant portion (terms x thru x 11 /11!) are on even lines, and the least significant portion (terms x 13 /13! thru x 21 /21!) are on odd lines. This is intended to avoid dependency stalls between instructions, which hampers performance.
The disclosed invention avoids placing the upper address bits of source and/or target register addresses directly in the instruction itself, as that would use up valuable opcode space. Instead, the upper, most significant address bits are taken from the least significant bits of the address of the instruction. Special instruction decode hardware decodes these special instructions and concatenates a least significant subset of instruction address bits onto the most significant portion of the register address. In this particular implementation of the invention, the least significant 2 bits of the instruction address are concatenated onto the most significant portion of each register address portion contained in the instruction. Instruction addresses are 64 bits in width in this implementation, and numbered from most significant bit 0 to least significant bit 63 . Full register addresses are 6 bits in width and numbered from most significant bit 0 to least significant bit 5 . In this example, bits 60 : 61 are concatenated onto the most significant side of each register address portion contained in the instruction, such that bits 60 : 61 from the instruction address become bits 0 : 1 of each full register address. Thus, the example above is altered to be unrolled 4 times (only a portion shown for brevity) note the instruction address on the left. The bits of the instruction address that are concatenated with the register addresses from the instruction are shown in bold.
Instruction
Address
bits (58:63)
Instruction
0b00 00 00:
zfmul
f2, f1, f2
# f1 contains x, initially f2 contains x also
0b00 01 00:
zfmul
f34, f33, f34
# (in memory this looks like zfmul, f2, f1, f2)
0b00 10 00:
zfmul
f66, f65, f66
# (in memory this looks like zfmul, f2, f1, f2)
0b00 11 00:
zfmul
f98, f97, f98
# (in memory this looks like zfmul, f2, f1, f2)
0b01 00 00:
zfmul
f2, f1, f2
# f2 now contains x raised to the desired exp
0b01 01 00:
zfmul
f34, f33, f34
# (in memory this looks like zfmul, f2, f1, f2)
0b01 10 00:
zfmul
f66, f65, f66
# (in memory this looks like zfmul, f2, f1, f2)
0b01 11 00:
zfmul
f98, f97, f98
# (in memory this looks like zfmul, f2, f1, f2)
0b10 00 00:
zfadd
f3, f3, f6
# increment the counter, initially contains 1
0b10 01 00:
zfadd
f35, f35, f38
# (in memory this looks like zfadd f3, f3, f6)
0b10 10 00:
zfadd
f67, f67, f70
# (in memory this looks like zfadd f3, f3, f6)
0b10 11 00:
zfadd
f99, f99, f102
# (in memory this looks like zfadd f3, f3, f6)
0b11 00 00:
zfmul
f4, f3, f4
# f4 contains the running factorial, init 1
0b11 01 00:
zfmul
f36, f35, f36
# (in memory this looks like zfmul f4, f3, f4)
0b11 10 00:
zfmul
f68, f67, f68
# (in memory this looks like zfmul f4, f3, f4)
0b11 11 00:
zfmul
f100, f99, f100
# (in memory this looks like zfmul f4, f3, f4)
0b11 01 00:
zfaddb
f10, f10, f42
# final sum (instr zfaddb uses IA for B only)
0b11 10 00:
zfaddb
f10, f10, f74
#
0b11 10 00:
zfaddb
f10, f10, f106
#
Therefore, consistent with one aspect of the invention, a computer system includes a register file configured to store a target result operand and to retrieve a source operand both addressed by register addresses, an execution unit for executing instructions, where the execution unit is configured to receive the source operand from the register file and write the target result operand into the register file. The computer system also includes a register address calculation logic configured to receive a current instruction address portion associated with a current instruction, a source register address portion and a target register address portion, and to concatenate the current instruction address portion onto the source register address portion and the target register address portion to yield a full source register address corresponding to the source operand and a full target register address corresponding to the target operand. The register address calculation logic is further configured to provide the full source register address and the full target register address to the register file. The computer system also includes an instruction decode logic configured to decode the current instruction and provide the current instruction address portion and the source and target register address portions to the register address calculation logic.
Consistent with another aspect of the invention, a method is provided for executing instructions in a processor, where, in response to receiving an instruction that corresponds to an instruction opcode that contains only a portion of the full register address in lieu of full addresses, the addresses are obtained by concatenating each individual address portion provided in the instruction with a least significant address portion obtained from the current instruction's instruction address to yield full register addresses. The full source and target addresses are then provided to the register file such that operand data can be read from the register file that is associated with the source addresses. This operand data is then used to execute the instruction, and the resultant target data is written into the register file entry associated with the full target address.
These and other advantages and features, which characterize the invention, are set forth in the claims annexed hereto and forming a further part hereof. However, for a better understanding of the invention, and of the advantages and objectives attained through its use, reference should be made to the drawings, and to the accompanying descriptive matter, in which there is described exemplary embodiments of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of exemplary automated computing machinery including an exemplary computer useful in data processing consistent with embodiments of the present invention.
FIG. 2 is a block diagram illustrating in greater detail an exemplary implementation of the processor in FIG. 1 .
FIG. 3 is a block diagram illustrating an exemplary implementation of an auxiliary instruction issue and execution logic consistent with the invention, and capable of being implemented within the processor of FIG. 2 .
FIG. 4 is a block diagram of an address calculation logic consistent with the invention, and capable of being implemented within the processor of FIG. 2 .
FIG. 5 is a flow chart illustrating an exemplary sequence of operations performed by the auxiliary instruction issue and execution logic of FIG. 3 to implement register address calculation using current instruction address consistent with the invention.
FIG. 6 is an illustration of two instruction formats, the first instruction format suitable for execution by a prior art computing system, and the second suitable to be executed by an AXU Auxiliary Execution unit consistent with the embodiment shown in FIGS. 1-5 .
DETAILED DESCRIPTION
Embodiments consistent with the invention utilize register address calculation using current instruction addresses to generate full register addresses suitable for usage by large register files. A portion of the full address is obtained from the instruction while the remainder of the full address is obtained from the current instruction address by register address calculation logic. The two portions are concatenated and sent to the execution unit to begin execution.
The hereinafter described embodiments allow for much greater opcode space in fixed instruction width architectures by using register address offsets that occupy fewer bits than the full source addresses, thereby freeing up more bits in the instruction for opcode space.
Other modifications will become apparent to one of ordinary skill in the art having the benefit of the instant disclosure.
Hardware and Software Environment
Now turning to the drawings, wherein like numbers denote like parts throughout the several views, FIG. 1 illustrates exemplary automated computing machinery including an exemplary computer 10 useful in data processing consistent with embodiments of the present invention. Computer 10 of FIG. 1 includes at least one computer processor 12 or ‘CPU’ as well as a random access memory 14 (‘RAM’), which is connected through a high speed memory bus 16 and a bus adapter 18 to processor 12 through a processor bus 34 .
Stored in RAM 14 is an application 20 , a module of user-level computer program instructions for carrying out particular data processing tasks such as, for example, word processing, spreadsheets, database operations, video gaming, stock market simulations, graphics simulations, atomic quantum process simulations, or other user-level applications. Also stored in RAM 14 is an operating system 22 . Operating systems useful in connection with embodiments of the invention include UNIX™, Linux™, Microsoft Windows XP™, AIX™, IBM's i5/OS™, and others as will occur to those of skill in the art. Operating system 22 and application 20 in the example of FIG. 1 are shown in RAM 14 , but many components of such software typically are stored in non-volatile memory also, e.g., on data storage such as a disk drive 24 .
Computer 10 of FIG. 1 includes a disk drive adapter 38 coupled through an expansion bus 40 and bus adapter 18 to processor 12 and other components of the computer 10 . Disk drive adapter 38 connects non-volatile data storage to the computer 10 in the form of disk drive 24 , and may be implemented, for example, using Integrated Drive Electronics (‘IDE’) adapters, Small Computer System Interface (‘SCSI’) adapters, and others as will occur to those of skill in the art. Non-volatile computer memory also may be implemented for as an optical disk drive, electrically erasable programmable read-only memory (so-called ‘EEPROM’ or ‘Flash’ memory), RAM drives, and so on, as will occur to those of skill in the art.
Computer 10 also includes one or more input/output (‘I/O’) adapters 42 , which implement user-oriented input/output through, for example, software drivers and computer hardware for controlling input and output to and from user input devices 44 such as keyboards and mice. In addition, computer 10 includes a communications adapter 46 for data communications with a data communications network 50 . Such data communications may be carried out serially through RS-232 connections, through external buses such as a Universal Serial Bus (‘USB’), through data communications networks such as IP data communications networks, and in other ways as will occur to those of skill in the art. Communications adapter 46 implements the hardware level of data communications through which one computer sends data communications to another computer, directly or through a data communications network. Examples of communications adapter 46 suitable for use in computer 10 include but are not limited to modems for wired dial-up communications, Ethernet (IEEE 802.3) adapters for wired data communications network communications, and 802.11 adapters for wireless data communications network communications. Computer 10 also includes a display adapter 32 which facilitates data communication between bus adapter 18 and a display device 30 , allowing application 20 to visually present output on display device 30 .
FIG. 2 next illustrates in detail one exemplary implementation of a processor 12 consistent with the invention, implemented as a processing element partitioned into an instruction unit (IU) 162 , an execution unit (XU) 164 and an auxiliary execution unit (AXU) 166 . In the illustrated implementation, IU 162 includes a plurality of instruction buffers (I Buffer) 168 that receive instructions from an L1 instruction cache (iCACHE) 170 . Each instruction buffer 168 is dedicated to one of a plurality, e.g., four, symmetric multithreaded (SMT) hardware threads. An effective-to-real translation unit (iERAT) 172 is coupled to iCACHE 170 , and is used to translate instruction fetch requests from a plurality of thread fetch sequencers 174 into real addresses for retrieval of instructions from lower order memory, through a bus interface controller 108 . Each thread fetch sequencer 174 is dedicated to a particular hardware thread, and is used to ensure that instructions to be executed by the associated thread is fetched into the iCACHE 170 for dispatch to the appropriate execution unit. As also shown in FIG. 2 , instructions fetched into instruction buffer 168 may also be monitored by branch prediction logic 176 , which provides hints to each thread fetch sequencer 174 to minimize instruction cache misses resulting from branches in executing threads.
IU 162 also includes a plurality of issue logic blocks 178 and is configured to resolve dependencies and control the issue of instructions from instruction buffer 168 to XU 164 . In addition, in the illustrated embodiment, a plurality of separate auxiliary instruction issue logic blocks 180 is provided in AXU 166 , thus enabling separate instructions to be concurrently issued by different threads to XU 164 and AXU 166 . In an alternative embodiment, (not illustrated) auxiliary instruction issue logic 180 may be disposed in IU 162 , or may be omitted in its entirety, such that issue logic 178 issues instructions to AXU 166 .
XU 164 is implemented as a fixed point execution unit, including a general purpose register (GPR) 182 and a special purpose register (SPR) 198 both coupled to fixed point logic 184 , a branch logic 186 and a load/store logic 188 . Load/store logic 188 is further coupled to an L1 data cache (dCACHE) 190 , with effective to real translation provided by a dERAT logic 192 . XU 164 may be configured to implement practically any instruction set, e.g., all or a portion of a 32b or 64b Power™ Architecture instruction set.
AXU 166 operates as an auxiliary execution unit including the auxiliary instruction issue logic 180 along with one or more execution blocks 194 . AXU 166 may include any number of execution blocks, and may implement practically any type of execution unit, e.g., a floating point unit, or one or more specialized execution units such as encryption/decryption units, generic coprocessors, cryptographic processing units, vector processing units, graphics processing units, XML processing units, etc. In the illustrated embodiment, AXU 166 includes high speed auxiliary interface 196 , to facilitate high speed communication between AXU 166 and XU 164 , e.g., to support direct moves between AXU register contents and XU register contents and other high speed communication between execution units.
Register Address Calculation Logic in an Issue Unit
FIG. 3 illustrates in further detail an exemplary AXU 166 suitable for implementation inside of processor 12 in FIG. 2 . AXU 166 is configured with auxiliary instruction issue logic 180 , which is configured to select fair issuance of instructions from multiple threads using an issue select logic 208 , which in turn issues instructions from the selected thread to an auxiliary execution block 194 . AXU 166 is also configured to decode instructions for each thread with an instruction decode logic 202 . Instruction decode logic 202 decodes instructions from its associated thread to determine if the current instruction supports register address calculation using current instruction address consistent with embodiments of the invention. In addition, instruction decode logic 202 obtains one or more address portions from the instruction and provides them to address calculation logic 300 . Instruction decode logic 202 also passes along a portion of the instruction address associated with that thread's current instruction. Address calculation logic 300 is configured to generate full register addresses by concatenating the least significant bits of the current instruction's address onto the most significant portion of each register address portion obtained from the instruction, and provide the full addresses and the instruction to dependency logic 204 . Dependency logic 204 is configured to resolve dependencies between instructions by stalling dependent instructions for the appropriate number of cycles, and pass the instruction and associated full addresses to issue select logic 208 .
Issue select logic 208 is configured to select fair issuance of instructions from available threads in the design, and issue instructions and full register addresses to auxiliary execution block 194 . Auxiliary execution block 194 includes a register file 210 coupled to an execution unit 214 . Register file 210 includes an array of registers, each of which are accessed by a unique address. For example, register file 210 may be implemented to support 64 registers, each accessed by a unique full 6-bit address. It will be appreciated that different numbers of registers may be supported in different embodiments.
Auxiliary execution block 194 is configured to obtain the full addresses from issue select logic 208 , and provide them to register file 210 , which in turn reads operand data associated with the full address, and provides the operand data to execution unit 214 . Execution unit 214 may be implemented as a number of different types of execution units, e.g., floating point units, fixed point units, or specialized execution units such as graphics processing units, encryption/decryption units, coprocessors, XML processing units, etc, and still remain within the scope and spirit of the present invention.
Execution unit 214 performs some operation on this operand data e.g., addition, subtraction, division, etc, depending on the type of instruction issued from issue select logic 208 . Execution unit 214 provides the resultant target data 212 from the operation to register file 210 , where it is stored internally at a location associated with a full address obtained from issue select logic 208 .
In a multithreaded design consistent with the invention, one group 200 of instruction decode logic 202 , address calculation logic 300 , and dependency logic 204 exists for each thread in the design. Alternatively, other embodiments may be implemented in a single threaded design, where only a single thread is issued to one group 200 of instruction decode logic 202 , address calculation logic 300 , and dependency logic 204 , and only one group 200 exists in the design.
FIG. 4 illustrates in further detail address calculation logic 300 , previously shown in FIG. 3 . This particular embodiment of address calculation logic 300 is designed to obtain the two least significant bits of the current instruction's instruction address (numbered 60:61) and concatenate those two bits onto the most significant portion of each register address portion (each numbered 2:5) contained in the current instruction. In the illustrated embodiment, the register address portions contained in the instruction are 4 bits each, and when each of these address portions are concatenated with the least 2 significant bits of the instruction address, this yields a 6-bit full address denoted as bits 0 : 5 which are suitable for addressing the 64 registers in the register file.
In the illustrated embodiment, four register address portions are obtained from the instruction. The instruction contains target address portion TA(2:5), and three source register address portions named AA(2:5), BA(2:5) and CA(2:5). Bits 60 : 61 of the instruction address are sent to multiplexers 302 A, 302 B, 302 C and 302 D. These multiplexers are configured to select instruction address 60:61 to be passed to each multiplexers output if the opcode valid from instruction decode logic 202 is 1, indicating that the current instruction is an instruction that requires the least significant portion of the instruction address to be concatenated with address portions from the instruction to yield full register addresses. If the opcode valid is 0, “00” is passed to the output of multiplexers 302 A, 302 B, 302 C and 302 D.
The outputs of multiplexers 302 A, 302 B, 302 C and 302 D are then concatenated onto the most significant end of register address portions TA(2:5), AA(2:5), BA(2:5) and CA(2:5), respectively. This yields full register addresses TA(0:5), AA(0:5), BA(0:5), and CA(0:5) which are sent to dependency logic 204 .
FIG. 5 illustrates a method 400 outlining a sequence of operations performed by auxiliary execution unit 166 when processing an instruction from an instruction stream, and supporting register address calculation using the current instruction address consistent with the invention. With this sequence of operations, the instruction is received in block 410 . Control then passes to block 420 , where a determination is made as to whether the instruction type of the incoming instruction is of the type that contains any address portions in place of full register addresses, as supported by an execution unit supporting register address calculation using the current instruction address consistent with the invention. If not, control passes to block 440 , where the register addresses are generated normally. Control then passes to block 450 where execution of the instruction is completed, and finally control passes back to block 410 to receive the next incoming instruction in the instruction stream.
If a determination is made in block 420 that the current instruction is of the type that contains address portions in lieu of full addresses for use in address calculation using the current instruction address consistent with the invention, then control passes to block 430 , where a least significant portion of the current instruction address is concatenated onto the most significant end of each register address portion contained in the instruction, yielding full register addresses, which are then used to read entries from the register file and start executing the instruction. Control then passes to block 450 , where the execution of the instruction is completed, and control passes back to block 410 to receive the next incoming instruction in the instruction stream.
FIG. 6 illustrates at 500 an exemplary instruction format able to be executed by AXU 166 . Instruction format 500 contains 32 bits where the bits include an instruction opcode 501 consisting of 6 bits, a 6-bit target address 502 , three 6-bit source addresses 504 A, 504 B and 504 C, and a 2-bit secondary opcode 506 . As discussed previously, the 2-bit opcode 506 limits the instruction type to only 4 subtypes of operations, yet typically many more are needed.
FIG. 6 also illustrates at 600 an exemplary instruction format supporting register address calculation using the current instruction address and able to be executed by AXU 166 and method 400 consistent with the invention. Instruction format 600 contains 32 bits where the bits include an instruction opcode 601 consisting of 6 bits, a 6-bit target address 602 , and three source register portions 604 A, 604 B, and 604 C consisting of 4 bits each. In addition, instruction format 600 contains secondary opcode 606 which is 8 bits. The wider secondary opcode 606 allows for a far greater number of instruction subtypes.
The 4-bit source address portions 604 A, 604 B and 604 C may each be used to be supplied as address portions to the address calculation logic 300 in FIG. 4 . In this manner, the source address portions from the instruction may be used to produce full register addresses by concatenating each register address portion from the instruction with the least significant bits from the instruction address.
Instruction format 600 may contain any number and combination of source address portions versus full source addresses and not depart from the scope of the invention. For instance, in place of source portion 604 A a full 6-bit register address may be used, reducing the number of available bits in the secondary opcode 606 to 6 bits. Opcodes such as opcode 601 and secondary opcode 606 in the instruction specify which source operands in the instruction are referenced by register addresses directly and which require address calculation by address calculation logic 300 . It should be also bet noted that the fixed instruction width may be something other than 32 bits, for instance 64 bits, and not depart from the scope or spirit of the invention
Embodiments of the present invention may be implemented within the hardware and software environment described above in FIGS. 1-6 . However, it will be appreciated by one of ordinary skill in the art having the benefit of the instant disclosure that the invention may be implemented in a multitude of different environments, and that other modifications may be made to the aforementioned hardware and software embodiment without departing from the spirit and scope of the invention. As such, the invention is not limited to the particular hardware and software environment disclosed herein.
Other modifications will be apparent to one of ordinary skill in the art having the benefit of the instant disclosure. Therefore, the invention lies in the claims hereinafter appended.
|
Due to the ever expanding number of registers and new instructions in modern microprocessor cores, the address widths present in the instruction encoding continue to widen, and fewer instruction opcodes are available, making it more difficult to add new instructions to existing architectures without resorting to inelegant tricks that have drawbacks such as source destructive operations. The disclosed invention utilizes specialized decode and address calculation hardware that concatenates a fixed number of least significant bits of the instruction address onto the most significant side of each register address portion contained in the instruction, yielding the full register address, instead of providing the full register address widths for every register used in the instruction. This frees up valuable opcode space for other instructions and avoids compiler complexity. This aligns nicely with how most loops are unrolled in assembly language, where independent operations are near each other in memory.
| 6
|
FIELD OF THE INVENTION
This invention relates to temperature compensating devices for compensating the effect of temperature changes in an electrical or electronic circuit. In particular, it relates to a temperature compensating device using embedded columnar thermistors for enhanced performance.
BACKGROUND OF THE INVENTION
Temperature compensating devices are important components in a wide variety of electrical and electronic circuits such as high frequency communication circuits. Communication circuits are typically constructed using components, such as semiconductor devices, whose properties change with temperature. For example, solid state amplifiers are made using semiconductor components, and the current carrying ability of these components decreases with increasing temperature, reducing the gain of the amplifier. In the absence of compensation, such temperature-induced changes can deteriorate the performance of the circuit.
One method for compensating temperature-induced changes in a communication circuit is to cascade the circuit with a temperature compensating device whose pertinent characteristics vary oppositely with temperature. For example, an amplifier can be cascaded with a compensating device that increases in gain with increasing temperature. The cascaded combination minimizes gain variation with temperature.
U.S. Pat. No. 5,332,981 issued to the present applicant and John Steponick on Jul. 26, 1994, and is incorporated herein by reference. The '981 patent, which is entitled “Temperature Variable Attenuator,” describes a passive temperature compensating device using at least two different thermistors which are deposited as films on a substrate. The temperature coefficients of the thermistors are different and are selected so that the attenuator changes at a controlled rate with temperature while the impedance of the attenuator remains substantially constant.
Difficulties with the '981 device arise because the thermistors are formed as thin, relatively large area films on the surface of a substrate. The films are unduly susceptible to changes in air temperature. Moreover, there can be substantial temperature gradients between the film-air interface and the film/substrate interface. As one consequence, forced air cooling can vary the thermistor temperature and produce unwanted gain ripple. Another difficulty is that the relatively large area of the film requires a relatively large substrate. This increases cost, consumes board space, and degrades high frequency performance. Accordingly there is a need for improved temperature compensating devices.
SUMMARY OF THE INVENTION
In accordance with the invention, a temperature compensating device comprises one or more columnar thermistors embedded within a substrate. Because the thermistors are substantially covered by the substrate, they are less susceptible to changes in air temperature and to temperature gradients. Moreover, within the substrate the thermistors can be made thicker and smaller in lateral area, permitting more compact, less expensive devices that exhibit improved high frequency performance. The devices can advantageously be fabricated using the low temperature co-fired ceramic (LTCC) process.
BRIEF DESCRIPTION OF THE DRAWINGS
The advantages, nature and various additional features of the invention will appear more fully upon consideration of the illustrative embodiments now to be described in detail in connection with the accompanying drawings. In the drawings:
FIG. 1 is a perspective view of an exemplary temperature compensating device;
FIGS. 2A, 2 B and 2 C are simplified top, side and bottom views of the device of FIG. 1;
FIG. 3 is a schematic circuit diagram of the device of FIG. 1;
FIG. 4 illustrates trimming of a thermistor in the FIG. 1 device;
FIG. 5 shows an alternative embodiment of a temperature compensating device; and
FIG. 6 illustrates trimming of a thermistor in the FIG. 5 device.
It is to be understood that the drawings are for illustrating the concepts of the invention and are not to scale.
DETAILED DESCRIPTION
Referring to the drawings, FIG. 1 illustrates a temperature compensating device 99 comprising a substrate 100 having a pair of major surfaces 101 , 102 (preferably parallel) and a plurality of thermistors 104 , 105 , 106 connected in a temperature compensating circuit. At least one thermistor comprises one or more columnar bodies 103 of thermistor material, i.e. the bodies extend substantially in the direction between the major surfaces. The columnar bodies 103 (hereinafter “columns”) are conveniently uniform in cross sectional area. However the area can vary along the longitudinal direction without serious disadvantage. The columns 103 can be interconnected by metallization patterns 107 A, 107 B, 108 A, 108 B on the major surfaces. The resistance of each thermistor, at a given temperature, depends directly on the column length, inversely on the column area and inversely on the number of columns interconnected by the metallization.
FIGS. 2A, 2 B and 2 C are top, side and bottom views respectively of the temperature compensating device of FIG. 1 having major surfaces 101 (top) and 102 (bottom). Each column 103 of thermistor material extends substantially in the direction between the major surfaces. Each column 103 has ends which are small compared to the lateral area embedded within the substrate. A plurality of thermistors 104 , 105 and 106 are defined by patterns of metallization interconnecting sets of columns 103 on the major surfaces. Conveniently the metallization contacts the column ends near the major surfaces. Specifically, metallization patterns 107 A, 107 B on surface 101 and patterns 108 A, 108 B on surface 102 interconnect the ends of four columns 103 into thermistor 104 , six columns into thermistor 105 and four columns into thermistor 106 . Conveniently, notches 109 A, 109 B mark input/output contacts. Notches 110 A, 110 B mark ground contacts. In addition to connecting the columns, the metallization patterns 107 A, 107 B, 108 A, 108 B also define the interconnected circuit configuration among the thermistors 104 , 105 , 106 . It can be seen, for example, that the metallization patterns of FIGS. 2A, 2 B interconnect the thermistors 104 , 105 , 106 into the Pi configuration temperature compensating circuit schematically shown in FIG. 3 . The operation of this and other suitable temperature compensating circuits is described in the aforementioned U.S. Pat. No. 5,332,981 and in Reference Data for Engineers: Radio, Electronics, and Communications , Seventh Edition, Howard W. Sams & Co., Indianapolis, Ind., 1985, page: 11-4 et seq.
As compared with prior temperature compensating devices using thin film thermistors, the columnar thermistor device of FIG. 1 reduces air temperature modulation and thermal gradient problems. No significant areas of the thermistor columns are exposed. Moreover the device can be made smaller in lateral area by utilizing the volume within the substrate.
An additional advantage is that the resistance values of individual thermistors can be easily trimmed. Since the thermistors are columns 103 connected in parallel, the ohmic value of each thermistor can be increased by disconnecting columns from the circuit. FIG. 4 illustrates a column 103 disconnected by a cut 400 through the metallization 108 . The metallization can be cut, for example, by laser, abrasion or chemical etching.
The temperature compensating device of FIG. 1 is advantageously fabricated using Low Temperature Co-fired Ceramic (LTCC) processing. Holes are punched in unfired (“green”) ceramic sheets. The thermistor columns 103 can be formed in the holes. The columns can occupy a single layer, as illustrated in FIG. 1, or be formed in multiple stacked layers. Advantageously the columns are created by filling prepunched holes with a sinterable thermistor material, as in the form of glass-based frits. The connecting electrodes are then formed on the appropriate surfaces as by printing with conductive ink, and the green sheets are stacked and fired.
The thermistor material can be negative coefficient of temperature material (“NTC” material) or positive coefficient of temperature (“PTC”) material. NTC thermistors are typically based on oxides such as MgO or barium titanate; PTC thermistors are typically platinum-based. The ohmic value of each thermistor is determined by the number of columns (n), the diameter of each column (d), the length of the column (l) and the resitivity of the materials ρ. Specifically, the resistance R=ρl/πn (d/2) 2 . It will be appreciated that the metallization pattern can be configured to form any one of a variety of temperature compensating circuits.
FIG. 5 is a simplified view of an alternative embodiment using laterally extending columnar thermistors 503 . In the embodiment of FIG. 1 the maximum dimension of each column 103 extends between the major surfaces. The embodiment of FIG. 5 is substantially similar except that the maximum dimension of each columnar body 503 extends laterally in a direction parallel to a major surface. This embodiment can be fabricated in substantially the same way as the embodiment of FIG. 1, but has the advantage of compactly providing lower levels of resistance.
FIG. 6 illustrates how a laterally extending columnar thermistor 503 A can be trimmed by a cut in the metallization.
The invention can now be understood more clearly by consideration of the following specific embodiment.
EXAMPLE
An exemplary device according to FIG. 1 can be fabricated using the DuPont LTCC system 951 described in the DuPont material data sheet titled 951 Low-Temperature Cofire Dielectric Tape. The tape is a mixture of organic binder and glass. When fired, the tape forms the ceramic substrate for the circuit. Individual circuits are formed on a large wafer and then singulated after processing. Prior to firing, holes or vias are punched in the tape. The holes correspond to the location of the thermistor columns and conductor connections between tape layers. After punching, the vias are filled with either DuPont 6141 silver conductor to form electrically conductive connections, or with Electroscience Laboratories NTC 2112 thermistor material to create thermistor columns. Printing is accomplished using a squeegee printer and a metal stencil. After printing the solvents in the material are dried at 70° C. for 30 minutes. Electrically conductive interconnections are then made by screen printing a metal ink such as DuPont 6142 silver. All conductor prints must be dried. After the via holes are filled and conductive traces are printed and dried, the separate tape layers are aligned, stacked, and tacked together using a high temperature (200° C.), 3 mm diameter tool. The stacked tapes are then laminated at 3000-4000 PSI at 70° C. After lamination the assembly is heated to ˜400° C. to burn off the organic materials in the tape layers. After burn-off, the assembly is heated to 850° C. to sinter the glass. As the assembly exits the furnace and cools, the circuit forms a solid ceramic mass. Individual circuits are separated from the wafer by dicing.
It is understood that the above-described embodiments are illustrative of only a few of the many possible specific embodiments, which can represent applications of the invention. Numerous and varied other arrangements can be made by those skilled in the art without departing from the spirit and scope of the invention.
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A temperature compensating device comprises one or more columnar thermistors embedded within a substrate. Because the thermistors are substantially covered by the substrate, they are less susceptible to changes in air temperature and to temperature gradients. Moreover, within the substrate the thermistors can be made thicker and smaller in lateral area, permitting more compact, less expensive devices that exhibit improved high frequency performance. The devices can advantageously be fabricated using the low temperature co-fired ceramic (LTCC) process.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates generally to an automotive vehicle body construction and more specifically to a tow device thereof which features increased structural strength and which serves to protect the lowermost components of the vehicle with accidental impact against the road surface.
2. Description of the Prior Art
In a known arrangement, a hook or the like has been welded or otherwise fixedly secured to an essentially horizontal vehicle underpanel at a location above the lowermost level of the vehicle bottom. This arrangement has suffered from a number of drawbacks, such as impaired accessibility and susceptibility to buckling or other deformation upon the application of an excessive load when a cable or similar device is connected to the hook.
In an effort to overcome these problems it has been hitherto proposed to increase the thickness and strength of the panel to which the hook is attached and/or to add a reinforcing member to the existing panel to locally reinforce same against the aforementioned buckling. While these measures have to some extent solved the problem, they have inherently added undesirable weight and cost to the vehicle.
SUMMARY OF THE INVENTION
The present invention features a tow device disposed between and fixedly connected to two panels defining part of the vehicle structure. At least one of the panels has a wall section essentially perpendicular to the vehicle underpanel and parallel to the longitudinal axis thereof. The tow device is affixed to this wall section so that upon application of a large moment of force to the tow device, the buckling phenomenon exhibited by prior art constructions is resisted by the orientation of the wall section with respect to the axis about which the moment of force acts and by the distribution of the moment through two panels rather than through a single panel to an interconnected adjacent panel. The increased resistance to buckling under relatively large force moments permits the tow device to simultaneously perform a protective function by projecting below the lowermost portion of the vehicle body (such as the fuel tank and the exhaust pipe) to prevent impacting of the vehicle bottom on the road surface should the wheel or wheels enter pot holes or the like in the road.
Additional objects, advantages and novel features of the invention will be set forth in the description which follows and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
The features and advantages of the tow device according to the present invention will be more clearly appreciated from the following description taken in conjunction with the accompanying drawings in which like reference numerals designate corresponding elements, and in which
FIG. 1 is a view of the rear half of an automobile showing the disposition of a device according to the present invention as well as (in broken line) of the prior art arrangement;
FIG. 2 is a sectional view taken along section line A--A of FIG. 1;
FIG. 3 is a sectional view taken along section line B--B of FIG. 2;
FIG. 4 is a front elevation of a second embodiment of the present invention;
FIG. 5 is a sectional view taken along section line D--D of FIG. 4;
FIG. 6 is a sectional view taken along section line E--E of FIG. 4;
FIG. 7 is an exploded perspective view showing the second embodiment the present invention and a recess formed in the vertical panel in which the device is mounted; and
FIG. 8 is a sectional view of the arrangement shown in FIG. 7.
DETAILED DESCRIPTION OF THE INVENTION
Turning now to the drawings and more specifically to FIGS. 1, 2 and 3, a first embodiment of the tow device of the present invention is illustrated. A vehicle 1 has a structural panel 2, which in this case defines the floor of the vehicle trunk. The structural panel 2 is reinforced by longitudinally extending structural members 4 and 5, which have substantially channel shaped cross sections. A fuel tank 6 is mounted between the structural members 4 and 5, and an exhaust pipe 7 is mounted to the vehicle adjacent the fuel tank.
The structural panel 2, defining the floor of the trunk (or floor panel as it will be referred to hereinafter), is formed with perpendicular wall sections 8 and 9, which mate with external body panels 10 and 11. The perpendicular wall section 9, as illustrated, is further formed with an essentially horizontal section 3 which mates with the external body panel 11 to define a spare tire well 12 or the like. As best shown in FIGS. 2 and 3, the first embodiment of the tow device 14 of the present invention is sandwiched between a downwardly depending flange 13 of the channel member 5, and the perpendicular wall section 9, and is fixedly connected to one or both by welding or the like. In the first embodiment, the tow device takes the form of a simple U-shaped bar, the ends of which are welded in an appropriately shaped recess 15 formed into either or both of said wall section 9 and said flange 13. In FIG. 3, the recess 15 is shown to be formed in the perpendicular wall section 9.
The second embodiment of the present invention is illustrated in FIGS. 4 to 8. This embodiment differs from the first in that the U-shaped bar 14, is initially fixed (by welding or the like) to a base plate or structural attachment member 16. The structural attachment member 16 is formed with a flat section 17 and a raised section 18. The raised section 18 is interposed between the ends of the U-shaped member 14 which are, in the illustrated embodiment, welded to both the raised and flat sections.
While the arrangement illustrated in FIGS. 4 to 6 could be easily attached to a flat surface of the perpendicular wall section 9, it is preferred to additionally form a recess 19 in the perpendicular wall section 9 for receiving the structural attachment member 19 therein. The attachment member 16 is formed with flanges 20 and 21 which respectively contact the inner top edge of the recess 19 and the bottom of the spare tire well 12. In the instance where the recess is not provided, it is possible to seat the the flange 20 against the inner surface of the longitudinally extending structural member 5.
Thus, in the second embodiment of the tow device, the U-shaped bar 14 is fixed initially to the base plate (structural attachment member) 16, and the combination is then fixed in the recess 19. In this manner, locating the tow device during production is facilitated, and outstanding structural rigidity results. A loading force on the U-shaped bar 14 acts essentially parallel to the vehicle's longitudinal axis, resulting in a force moment about an axis essentially normal thereto tending to rotate the bar and attachment member 16. Due to the construction of the attachment member 16 including the raised section 18 and the perpendicular wall section 9 including the recess 19, the structural integrity of the wall section is greatly increased, thereby preventing the wall section 9 and the structural member flange 13 from buckling even under extreme conditions of excessive loading forces.
Accordingly, due to its inherent resistance to deformation, the two device projects as illustrated in FIG. 1, below the lowermost level of the vehicle body (in contrast with the prior art arrangement 22 illustrated in broken lines in FIG. 1) to define a definite degree of protection of the vehicle components such as the fuel tank 6 and exhaust pipe 7, in the event the vehicle should bottom out on its suspension due to various road conditions.
Thus, with the disclosed embodiments of the present invention it will be appreciated that without the need for increasing the thickness and strength of material from which the members such as the structural member 5 are formed, and without the need for any additional reinforcement panels, the present invention provides sufficient structual strength and rigidity to permit the tow device to serve as both a tow device and a protective device.
Further, it will be appreciated that the present invention is not limited to the rear of the vehicle and can be applied to front of same with equal effect.
The foregoing description of the preferred embodiments of the invention have been presented for purposes of illustration and description. They are not intended to be exhaustive or to limit the invention to the precise forms disclosed, and obviously many modifications and variations are possible in light of the above teachings. The embodiments were chosen and described in order to best explain the principles of the invention and its practical application to thereby enable others skilled in the art to best utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the claims appended hereto.
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A tow device is mounted between two structural members of a vehicle which share in absorbing a moment of force transmitted through the device when the vehicle is towed. One of the structural members is substantially normal to the axis about which the moment of force acts to provide resistance to structural deformation, while permitting the device to project below the vehicle body proper to prevent accidental impacting of the vehicle underbody on the road.
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RELATED APPLICATIONS
This application is a continuation of U.S. application Ser. No. 13/465,829, filed on May 7, 2012, which claims the benefit of U.S. Provisional Application Ser. No. 61/483,586 filed May 6, 2011, as well as U.S. Provisional Application Ser. No. 61/487,372 filed May 18, 2011, the contents of both of which are incorporated herein by reference in their entireties as if set forth in full.
BACKGROUND
1. Field of the Invention
The embodiments described herein relate generally to the field of radio-frequency identification (RFID) devices, and more particularly, to RFID switch tags.
2. Related Art
Conventional RFID tags lack the ability to be deactivated. However, there are certain situations where it is actually desirable to have an RFID tag deactivated. For example, in the context of traveling, RFID tags will often contain sensitive personal information stored within, for instance, an e-Passport, a visa, or a national identification card. Such information may contain the traveler's name, birth date, place of birth, nationality, and/or biometric information associated with that traveler. This information is intended to be read only by customs officials or other governmental authorities when the traveler enters or exits a country. However, since the read range of RFID tags can extend up to 30 feet, since an RFID tag does not need to be directly in the line of sight of an RFID reader, this sensitive information may be read by any number of unauthorized individuals as the individual walks through a train station or an airport. Unless the traveler houses his travel documents within a Faraday shield or other type of electro-resistant casing (which most travelers do not have), the sensitive information stored within the RFID tag remains perpetually at risk of being read by these unauthorized parties.
As a second example, consider RFID tags that are installed within automobiles, where such tags are used to facilitate automatic billing for the repeated use of certain toll-roads. In some of these toll-roads, the use of a car-pool lane is considered free of charge (which may be validly used, for example, when the automobile is housing at least one passenger other than the driver). Since a driver's RFID tag may not be deactivated, however, the RFID tag may respond to an interrogation signal issued from the toll-gate even when the driver has validly used the carpool lane. The result is that the driver may be billed for using the toll-road even when such use should have been considered free of charge because of the driver's valid use of the car-pool lane.
What is needed is a system for an RFID tag that may be easily activated or deactivated. Ideally, the system should be versatile and provide a clear sensory indication of the operational status of the RFID tag (i.e., activated or deactivated).
SUMMARY
Various embodiments of the present invention are directed to RFID switch devices. Such RFID switch devices advantageously enable manual activation/deactivation of the RF module. The RFID switch device may include a RF module with an integrated circuit adapted to ohmically connect to a substantially coplanar conductive trace pattern, as well as booster antenna for extending the operational range of the RFID device. The operational range of the RFID switch device may be extended when a region of the booster antenna overlaps a region of the conductive trace pattern on the RF module via inductive or capacitive coupling. In some embodiments, all or a portion of the booster antenna may at least partially shield the RF module when the RFID switch device is in an inactive state. The RFID switch device may further include a visual indicator displaying a first color if the RFID switch device is in an active state and/or a second color if the RFID switch device is in an inactive state.
In a first exemplary aspect, an RFID device is disclosed. In one embodiment, the RFID device comprises: a booster antenna adapted to extend the operational range of the RFID device; an RF module comprising an integrated circuit and a set of one or more conductive traces, wherein at least one conductive trace of said set of one or more conductive traces is adapted to electrically couple to a coupling region of the booster antenna when the coupling region of the booster antenna is located in a first position relative to said set of one or more conductive traces; and a switching mechanism adapted to change the position of the coupling region of the booster antenna relative to the position of said at least one conductive trace.
In a second exemplary aspect, an RFID transponder is disclosed. In one embodiment, the RFID transponder comprises: a first substrate comprising a first conductive trace pattern, wherein at least a portion of the first substrate is adapted to serve as an antenna for the RFID transponder; a second substrate comprising an integrated circuit and a second conductive trace pattern, wherein at least a portion of the second conductive trace pattern is adapted to electrically couple with at least a portion of the first conductive trace pattern when the first substrate is located in a first position relative to the second substrate; and a switching mechanism adapted to switch the position of the first substrate between a first position and at least a second position.
In a third exemplary aspect, an RFID device is disclosed. In one embodiment, the RFID device comprises: a booster antenna adapted to extend the operational range of the RFID device; a first RF module comprising a first integrated circuit and a first conductive trace pattern, wherein at least a portion of the first conductive trace pattern is adapted to electrically couple to a coupling region of the booster antenna when the coupling region of the booster antenna is located in a first position relative to the first conductive trace pattern; a second RF module comprising a second integrated circuit and a second conductive trace pattern, wherein at least a portion of the second conductive trace pattern is adapted to electrically couple to the coupling region of the booster antenna when the coupling region of the booster antenna is located in a second position relative to the second conductive trace pattern; and a switching mechanism adapted to change the position of the coupling region of the booster antenna relative to the positions of said first and second RF modules.
In a fourth exemplary aspect, an RFID device is disclosed. In one embodiment, the RFID device comprises: a first booster antenna adapted to extend the operational range of a first RF module; a second booster antenna adapted to extend the operational range of a second RF module; the first RF module comprising a first integrated circuit and a first conductive trace pattern, wherein at least a portion of the first conductive trace pattern is adapted to electrically couple to a coupling region of the first booster antenna when the coupling region of the first booster antenna is located in a first position relative to the first conductive trace pattern; a second RF module comprising a second integrated circuit and a second conductive trace pattern, wherein at least a portion of the second conductive trace pattern is adapted to electrically couple to the coupling region of the second booster antenna when the coupling region of the second booster antenna is located in a second position relative to the second conductive trace pattern; and a switching mechanism adapted to change the position of the coupling region of the first booster antenna relative to the first RF module, and the position of the coupling region of the second booster antenna relative to the second RF module.
In a fifth exemplary aspect, an RFID device is disclosed. In one embodiment, the RFID device comprises: a first booster antenna adapted to extend the operational range of an RF module as used with a first RFID service; a second booster antenna adapted to extend the operational range of the RF module as used with a second RFID service; the RF module comprising an integrated circuit and a conductive trace pattern, wherein at least a portion of the conductive trace pattern is adapted to electrically couple to a coupling region of the first booster antenna when the coupling region of the first booster antenna is located in a first position relative to the conductive trace pattern; and wherein at least a portion of the conductive trace pattern is adapted to electrically couple to a coupling region of the second booster antenna when the coupling region of the second booster antenna is located in a second position relative to the conductive trace pattern; and a switching mechanism adapted to change the position of the RF module relative to the respective coupling regions of the first and second booster antennas.
Other features and advantages of the present invention should become apparent from the following description of the preferred embodiments, taken in conjunction with the accompanying drawings, which illustrate, by way of example, the principles of the invention.
BRIEF DESCRIPTION OF THE DRAWINGS
Various embodiments disclosed herein are described in detail with reference to the following figures. The drawings are provided for purposes of illustration only and merely depict typical or exemplary embodiments. These drawings are provided to facilitate the reader's understanding of the invention and shall not be considered limiting of the breadth, scope, or applicability of the embodiments. It should be noted that for clarity and ease of illustration these drawings are not necessarily made to scale.
FIG. 1 is a block diagram illustrating an exemplary RFID system according to one embodiment of the present invention.
FIG. 2A is a block diagram illustrating an exemplary RFID switch tag with its RF module located in a first position relative to its booster antenna according to one embodiment of the present invention.
FIG. 2B is a block diagram of the exemplary RFID switch tag with its RF module located in a second position relative to its booster antenna according to the embodiment depicted in FIG. 2A .
FIG. 2C is a block diagram of the RFID switch tag depicted in FIGS. 2A and 2B as depicted within an exemplary casing featuring a position-altering mechanism according to one embodiment of the present invention.
FIG. 3 is a block diagram illustrating an exemplary RFID switch tag including two RF modules and a single booster antenna according to one embodiment of the present invention.
FIG. 4 is a block diagram illustrating an exemplary RFID switch tag including two RF modules and two corresponding booster antennas according to one embodiment of the present invention.
FIG. 5 is a block diagram illustrating an exemplary RFID switch tag including a single RF module and two booster antennas that are tuned to different frequencies according to one embodiment of the present invention.
FIG. 6A is a front-side view of an exemplary switch-activated RFID tag according to one embodiment of the present invention.
FIG. 6B is a perspective view of the back side of the exemplary switch-activated RFID tag according to the embodiment depicted in FIG. 6A .
FIG. 7A is a back-side view of an exemplary circular-shaped and rotatable RFID switch tag in a first position according to one embodiment of the present invention.
FIG. 7B is a back-side view of the exemplary circular-shaped and rotatable RFID switch tag in a second position according to the embodiment depicted in FIG. 7A .
FIG. 7C is a front-side view of the exemplary circular-shaped and rotatable RFID switch tag depicted in FIGS. 7A and 7B .
FIG. 8A is a perspective view of the back side of an exemplary triangular-shaped and rotatable RFID switch tag in a first position according to one embodiment of the present invention.
FIG. 8B is a back-side view of the exemplary triangular-shaped and rotatable RFID switch tag in a second position according to the embodiment depicted in FIG. 8A .
FIG. 8C is a front-side of the exemplary triangular-shaped and rotatable RFID switch tag depicted in FIGS. 8A and 8B .
FIG. 9A is a perspective view of the back side of an exemplary switch-activated RFID tag according to one embodiment of the present invention.
FIG. 9B is a front-side view of the exemplary switch-activated RFID tag depicted in FIG. 9A .
FIG. 10 is a perspective view of an exemplary slide-activated RFID tag according to one embodiment of the present invention.
DETAILED DESCRIPTION
RFID is an automatic identification method, relying on storing and remotely retrieving data using devices called RFID tags or transponders. The technology relies on cooperation between an RFID reader and an RFID tag. RFID tags can be applied to or incorporated within a variety of products, packaging, and identification mechanisms for the purpose of identification and tracking using radio waves. For example, RFID is used in enterprise supply chain management to improve the efficiency of inventory tracking and management. Some tags can be read from several meters away and beyond the line of sight of the RFID reader.
Most RFID tags contain at least two parts: One is an integrated circuit for storing and processing information, for modulating and demodulating a radio-frequency (RF) signal, and for performing other specialized functions. The second is an antenna for receiving and transmitting the signal. As the name implies, RFID tags are often used to store an identifier that can be used to identify the item to which the tag is attached or incorporated. An RFID tag may also contain non-volatile memory for storing additional data as well. In some cases, the memory may be writable or electrically erasable programmable read-only memory (i.e., EEPROM).
Most RFID systems use a modulation technique known as backscatter to enable the tags to communicate with the reader or interrogator. In a backscatter system, the interrogator transmits a Radio Frequency (RF) carrier signal that is reflected by the RFID tag. In order to communicate data back to the interrogator, the tag alternately reflects the RF carrier signal in a pattern understood by the interrogator. In certain systems, the interrogator can include its own carrier generation circuitry to generate a signal that can be modulated with data to be transmitted to the interrogator.
RFID tags come in one of three types: passive, active, and semi passive. Passive RFID tags have no internal power supply. The minute electrical current induced in the antenna by the incoming RF signal from the interrogator provides just enough power for the, e.g., CMOS integrated circuit in the tag to power up and transmit a response. Most passive tags transmit a signal by backscattering the carrier wave from the reader. This means that the antenna has to be designed both to collect power from the incoming signal and also to transmit the outbound backscatter signal.
Passive tags have practical read distances ranging from about 10 cm (4 in.) (ISO 14443) up to a few meters (Electronic Product Code (EPC) and ISO 18000-6), depending on the chosen radio frequency and antenna design/size. The lack of an onboard power supply means that the device can be quite small. For example, commercially available products exist that can be embedded in a sticker, or under the skin in the case of low frequency RFID tags.
Unlike passive RFID tags, active RFID tags have their own internal power source, which is used to power the integrated circuits and to broadcast the response signal to the reader. Communications from active tags to readers is typically much more reliable, i.e., fewer errors, than from passive tags. Active tags, due to their on-board power supply, may also transmit at higher power levels than passive tags, allowing them to be more robust in “RF challenged” environments, such as high environments, humidity or with dampening targets (including humans/cattle, which contain mostly water), reflective targets from metal (shipping containers, vehicles), or at longer distances. In turn, active tags are generally bigger, caused by battery volume, and more expensive to manufacture, caused by battery price. Many active tags today have operational ranges of hundreds of meters, and a battery life of up to 10 years. Active tags can include larger memories than passive tags, and may include the ability to store additional information received from the reader, although this is also possible with passive tags.
Semi-passive tags are similar to active tags in that they have their own power source, but the battery only powers the microchip and does not power the broadcasting of a signal. The response is usually powered by means of backscattering the RF energy from the reader, where energy is reflected back to the reader as with passive tags. An additional application for the battery is to power data storage. The battery-assisted reception circuitry of semi-passive tags leads to greater sensitivity than passive tags, typically 100 times more. The enhanced sensitivity can be leveraged as increased range (by one magnitude) and/or as enhanced read reliability (by reducing bit error rate at least one magnitude).
FIG. 1 is a block diagram illustrating an exemplary RFID system according to one embodiment of the present invention. As shown by this figure, RFID interrogator 102 communicates with one or more RFID tags 110 . Data can be exchanged between interrogator 102 and RFID tag 110 via radio transmit signal 108 and radio receive signal 112 . RFID interrogator 102 may include RF transceiver 104 , which contains both transmitter and receiver electronics configured to respectively generate and receive radio transit signal 108 and radio receive signal 112 via antenna 106 . The exchange of data may be accomplished via electromagnetic or electrostatic coupling in the RF spectrum in combination with various modulation and encoding schemes.
RFID tag 110 can be a transponder attached to an object of interest and serve as an information storage mechanism. The RFID tag 110 may itself contain an RF module 120 (including an integrated circuit 122 and conductive trace pattern 124 ) as well as its own antenna 126 . All or a portion of the antenna 126 may be adapted to interact with the conductive trace pattern 124 in order to gather energy from the RF field to enable the device circuit 122 to function. In some embodiments, the antenna 126 used to gather the RF energy may be in a different plane as that of the integrated circuit 122 .
The data in the transmit signal 108 and receive signals 112 may be contained in one or more bits for the purpose of providing identification and other information relevant to the particular RFID tag application. When RFID tag 110 passes within the range of the radio frequency magnetic or electromagnetic field emitted by antenna 106 , RFID tag 110 is excited and transmits data back to RF interrogator 102 . A change in the impedance of RFID tag 110 can be used to signal the data to RF interrogator 102 via the receive signal 112 . The impedance change in RFID tag 110 can be caused by producing a short circuit across the tag's antenna connections (not shown) in bursts of very short duration. RF transceiver 104 can sense the impedance change as a change in the level of reflected or backscattered energy arriving at antenna 106 .
Digital electronics 114 (which in some embodiments comprises a microprocessor with RAM) performs decoding and reading of the receive signal 112 . Similarly, digital electronics 114 performs the coding of the transmit signal 108 . Thus, RF interrogator 102 facilitates the reading or writing of data to RFID tags, e.g. RFID tag 110 that are within range of the RF field emitted by antenna 104 . Together, RF transceiver 104 and digital electronics 114 comprise reader 118 . Finally, digital electronics 114 and can be interfaced with an integral display and/or provide a parallel or serial communications interface to a host computer or industrial controller, e.g. host computer 116 .
As stated above, conventional RFID devices lack the ability to be manually activated or deactivated. Various embodiments of the present invention are therefore directed to an RFID switch tag adapted to allow a user to manually change the operational state of the RFID device by activation of a lever, switch, knob, slider, rotating member, or other similar structure.
As shown generally by the embodiments depicted in FIGS. 2A-2C , a tag may provided that includes an RF module, strap, or interposer, as well as a booster antenna 210 . The RF module 220 may comprise an RFID integrated circuit in an ohmic connection to impedance matched conductive trace pattern in the same plane as the integrated circuit. Even though the RF module 220 is fully functional and testable, it may have a limited range of operation due to the small surface area of the conductive trace pattern.
According to one embodiment, the operational range of the RF module 220 can be increased by conductive or inductive coupling. For example, an impedance matched booster antenna 210 can be used in conjunction with the RF module 220 . In one embodiment, this booster antenna 210 consists of a conductive trace pattern on a substrate. In this example, there is no RF device on the booster antenna 210 . Rather, the RF module 220 and booster antenna 210 are provided with an area where they can overlap so that the capacitive or inductive coupling of energy occurs. The RF energy gathered from the booster antenna 210 may be transferred through the RF module substrate and conducted into the RF module 220 . This is illustrated in FIG. 2A . As shown, the RF module 220 may be positioned relative to the booster antenna 210 such that RF energy gathered via the booster antenna 210 is transferred to the RF module 220 .
While not shown, RF module 220 may comprise an RFID integrated circuit and a conductive trace pattern. These trace patterns can then be either inductively or capacitively coupled with a booster antenna 210 . For optimal performance, the booster antenna 210 may be matched with the RFID integrated circuit inputs. If RF module 220 is displaced or not sufficiently coupled with antenna 210 , then the operational range of the tag can be significantly reduced.
Thus, the placement of the RF module 220 with respect to the booster antenna 210 may alter the operational range and performance of the RFID tag 110 . This is illustrated in FIG. 2B . In FIG. 2B , the relative positions of the RF module 220 and the booster antenna 210 are different than the arrangement shown in FIG. 2A . In the arrangement of FIG. 2B , a smaller portion, or none, of the RF energy collected by the booster antenna 210 is transferred to the RF module 220 . In this manner, the effective operational range of the RFID tag 110 may be reduced as compared to the arrangement of FIG. 2A . In fact, because RF module 220 is completely or at least partially shielded by a portion of antenna 210 , RFID communications between the RFID tag 110 and the RFID reader interrogator 102 may be completely halted. This non-operational state may be useful, for instance, in situations where it is desirable to render the RFID tag 110 unresponsive to an RFID interrogation signal. For example, as noted above, when no toll is due on a toll road due to the number of passengers in the car, it may be desirable for the RFID tag 110 to be unresponsive to an RFID interrogation issued by a toll road portal system.
In some embodiments, a mechanism is provided for selectively altering the relative position of RF module 220 and the booster antenna 210 . Advantageously, this allows a user to selectively displace the RF module 220 from an optimized position over the booster antenna 210 rendering it unresponsive or detuned such that it will not respond at a sufficient measurement or perform adequately. Thus, for example, when taking a toll road that is free for car-pools, a user can manipulate the mechanism in order to effectively deactivate the RFID tag 110 and avoid paying the toll. In various embodiments, the mechanism may include a switch, lever, knob, slider, rotatable member, or any other device or construction which serves this purpose.
A selectively-activatable RFID tag 110 is depicted in FIG. 2C . The RFID tag 110 may comprise a slider mechanism 240 and an indicator area 250 , where the RF module 220 is mechanically coupled to the slider 240 . By manipulating the slider, a user modifies the relative positions of the RF module 220 and the booster antenna 210 . The indicator area 250 may provide a visual indication of the status of the RFID tag 110 . For example, if the RF module 220 and booster antenna 210 are positioned for effective transfer of RF power, the indicator area 250 may present a first visual indication such as a green color. Conversely, if the RF module 220 and booster antenna 210 are not positioned for effective transfer of RF power, the indicator area may provide a second visual indication such as a red color. In this manner, one or more individuals can be alerted of the effective operability of the RFID tag 110 .
FIG. 3 is a block diagram illustrating an exemplary RFID switch tag including two RF modules and a single booster antenna according to one embodiment of the present invention. As shown, a single booster antenna 310 is provided. However, in this embodiment two RF modules 322 and 324 are shown. The booster antenna 310 and RF modules 322 and 324 may be positioned such that only one of the two modules 322 and 324 is effectively coupled to the booster antenna 310 at any one time. For example, as shown in FIG. 3 , RF module 322 is coupled to the booster antenna 310 while RF module 324 is shielded. Thus, RF module 322 is effectively tuned and responsive, while RF module 324 is effectively detuned and unresponsive.
A mechanism (e.g., switch, slider, knob, lever, rotatable member, etc.) such as the slider 240 depicted in FIG. 2C may be provided for selectively altering the relative position of RF module 322 and 324 and the booster antenna 310 . In this manner, the positioning altering mechanism can be manipulated to selectively cause zero or one of the two modules 322 and 324 to be coupled to the antenna 310 . For example, in a first state, only module 322 may be coupled with the booster antenna 310 . In a second state, only module 324 may be coupled with booster antenna 310 . In a third state, neither modules 322 or 324 are coupled with the booster antenna 310 .
Advantageously, this arrangement allows a single RFID tag 110 to be used for multiple services. For example, one RF module, e.g. module 322 , can be associated with toll road portal system. The other RF module, e.g., module 324 , can be associated with a system for tracking car-pool lane use. The user can manipulate the position altering mechanism in order to couple the booster antenna 310 to the RF module 322 or 324 that is appropriate for current usage. In some embodiments, one or more visuals indicators may also be provided to indicate which RF module 322 or 324 is currently coupled to the booster antenna. Note also that while only two RF modules 322 and 324 are depicted in FIG. 3 , any number of RF modules may be used in accordance with embodiments of the present invention.
In the embodiment of FIG. 3 , the RF modules 322 and 324 may be aligned horizontally and the direction of movement caused by manipulation of the position altering mechanism may likewise be horizontal. In other embodiments, however, the RF modules 322 and 324 may be aligned vertically and the direction of movement may be vertical. In still other embodiments, the RF modules 322 , 324 may be arranged in an arcuate manner and the direction of motion may also be arcuate. Various other arrangements of the RF modules 322 and 324 , the booster antenna 310 , and the direction of movement are also possible according to embodiments of the present invention.
FIG. 4 is a block diagram illustrating an exemplary RFID switch tag including two RF modules and two corresponding booster antennas according to one embodiment of the present invention. As shown by the figure, two booster antennas 412 and 414 and two RF modules 422 and 424 are provided. In some embodiments, each RF module 422 and 424 may be associated with a different RFID service such that a user may independently tune each pair of RF modules 422 and 424 and booster antennas 412 and 414 present within the RFID tag 110 . Note that while only two pairs of RF modules 422 and 424 and booster antennas 412 and 414 are depicted in FIG. 4 , any number of RF module/booster antenna pairs may be utilized according to embodiments of the present invention.
While the embodiment depicted in FIG. 4 depicts the antennas 412 and 414 as bearing similar physical properties (such as size and shape), each booster antenna 412 and 414 may have differing physical properties according to alternative embodiments. These differences may result in different properties for gathering RF energies. In some embodiments, the antennas 412 and 414 may be specifically tuned to different frequencies.
According to some embodiments, each of the RF modules 422 and 424 may be attached to single position altering mechanism (not shown). In this manner, a user can manipulate the mechanism such that only one of the two RF modules 422 and 424 is coupled to its respective boost antenna 412 or 414 at any one time. A visual indicator may be provided to indicate which RF module 422 or 424 is currently coupled to its respective booster antenna 412 and 414 . In some embodiments, the position altering mechanism may be manipulated such that both or neither of the RF modules 422 or 424 are coupled to the respective boost antennas 412 or 414 at the same time.
In other embodiments, each of the RF modules 422 and 424 may be attached to a separate position altering mechanism (not shown). According to these embodiments, both, neither, or only one of the RF modules 422 or 424 may be coupled to the respective boost antennas 412 and 414 at the same time. The visual indicator may display a first color if the first RF module 422 is active and a second color if the second RF module 424 is active.
Note that in the embodiment depicted in FIG. 4 , the booster antennas 412 and 414 may be arranged along a vertical axis, and a horizontal direction of motion is utilized via manipulation of the position altering mechanism. However, persons skilled in the art will appreciate that the booster antennas 412 and 414 may be arranged horizontally, vertically, along an arc, in different planes, or in various other manners. Additionally, the direction of motion may switch the RF modules 422 and 424 between coupled and uncoupled positions for the respective booster antennas 412 and 414 .
FIG. 5 is a block diagram illustrating an exemplary RFID switch tag including a single RF module and two booster antennas that are tuned to different frequencies according to one embodiment of the present invention. As shown, a single RF module 520 may be provided, along with two booster antennas 512 and 514 . The booster antennas 512 and 514 may be configured with different physical properties to enable the RF module 520 to switch between separate RFID services. In this respect, the RF module 520 may be mechanically coupled to a position altering mechanism such that the tag can be switched to select one or none of the booster antennas 512 and 514 . A visual indicator may display a first color if the first booster antenna 512 corresponding to a first RFID service is selected and a second color if the second booster antenna 514 corresponding to a second RFID service is selected.
As in the case of FIG. 4 , the booster antennas 512 and 514 may be arranged along a vertical axis and the direction of motion of the RF module 520 caused by manipulation of the position altering mechanism is vertical. In other embodiments, the booster antennas 512 and 514 may be arranged horizontally, along an arc, in different planes, or in another manner and the direction of motion is adapted to switch the RF module 520 between the booster antennas 512 and 514 .
FIGS. 6A-10 generally depict various embodiments of RFID switch tags which may be utilized, for example, within an automobile setting. Each of the RFID switch tags may be affixed, fastened, or adhered to a windshield, rearview mirror, automobile exterior, or to various other areas of the automobile according to embodiments of the present invention.
FIG. 6A is a front-side view of an exemplary switch-activated RFID tag according to one embodiment of the present invention, while FIG. 6B is a perspective view of the back side of the exemplary switch-activated RFID tag according to the embodiment depicted in FIG. 6A . As shown by the figure, the RFID tag may include a slider configuration 602 with a window 604 on the outside and one or more icon graphics 606 on the opposite side. In some embodiments, an optional mounting component (not shown) may be used to adhere, fasten, or clip the RFID tag to a visor, for example.
FIG. 7A is a back-side view of an exemplary circular-shaped and rotatable RFID switch tag in a first position according to one embodiment of the present invention, FIG. 7B is a back-side view of the exemplary circular-shaped and rotatable RFID switch tag in a second position according to the embodiment depicted in FIG. 7A , while FIG. 7C is a front-side view of the exemplary circular-shaped and rotatable RFID switch tag depicted in FIGS. 7A and 7B . As depicted in FIGS. 7A and 7B , a circular shaped member 702 may be rotated, for example, clockwise or counterclockwise, in order to activate or deactivate the RFID switch tag. Icon graphics 706 on the back-side may be used to inform one or more individuals of the activation state of the RFID switch tag. Optionally, a window 704 on the opposite side of the RFID switch tag (see FIG. 7C ) may be used to reveal the activation state of the RFID switch tag to the outside.
FIG. 8A is a perspective view of the back side of an exemplary triangular-shaped and rotatable RFID switch tag in a first position according to one embodiment of the present invention, FIG. 8B is a back-side view of the exemplary triangular-shaped and rotatable RFID switch tag in a second position according to the embodiment depicted in FIG. 8A , while FIG. 8C is a front-side of the exemplary triangular-shaped and rotatable RFID switch tag depicted in FIGS. 8A and 8B . FIGS. 8A-8C may operate similar to FIG. 7A-7C , but utilize a substantially triangular shape and design rather than a circular one. Various other shapes and designs may also be utilized in accordance with embodiments of the present invention.
FIG. 9A is a perspective view of the back side of an exemplary switch-activated RFID tag according to one embodiment of the present invention, while FIG. 9B is a front-side view of the exemplary switch-activated RFID tag depicted in FIG. 9A . As depicted in FIG. 9A , the RFID tag may utilize a slider configuration 902 with a windows on both sides 904 and 905 of the RFID tag. Such an RFID tag may be adhered to the window of the automobile or may also use a cradle system for mobility according to various embodiments.
FIG. 10 is a perspective view of a separate exemplary slide-activated RFID tag according to one embodiment of the present invention. According to some embodiments, no physical switch or level is utilized. Instead, the RFID tag may be activated or deactivated by manually sliding a first substrate 1002 to or from a casing 1004 .
While various embodiments of the present invention have been described above, it should be understood that they have been presented by way of example only, and not of limitation. The breadth and scope of the present invention should not be limited by any of the above-described exemplary embodiments. Where this document refers to technologies that would be apparent or known to one of ordinary skill in the art, such technologies encompass those apparent or known to the skilled artisan now or at any time in the future. In addition, the invention is not restricted to the illustrated example architectures or configurations, but the desired features can be implemented using a variety of alternative architectures and configurations. As will become apparent to one of ordinary skill in the art after reading this document, the illustrated embodiments and their various alternatives can be implemented without confinement to the illustrated example. One of ordinary skill in the art would also understand how alternative functional, logical or physical partitioning and configurations could be utilized to implement the desired features of the present invention.
Furthermore, although items, elements or components of the invention may be described or claimed in the singular, the plural is contemplated to be within the scope thereof unless limitation to the singular is explicitly stated. The presence of broadening words and phrases such as “one or more,” “at least,” “but not limited to” or other like phrases in some instances shall not be read to mean that the narrower case is intended or required in instances where such broadening phrases may be absent.
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Various embodiments of RFID switch devices are disclosed herein. Such RFID switch devices advantageously enable manual activation/deactivation of the RF module. The RFID switch device may include a RF module with an integrated circuit adapted to ohmically connect to a substantially coplanar conductive trace pattern, as well as booster antenna for extending the operational range of the RFID device. The operational range of the RFID switch device may be extended when a region of the booster antenna overlaps a region of the conductive trace pattern on the RF module via inductive or capacitive coupling. In some embodiments, all or a portion of the booster antenna may at least partially shield the RF module when the RFID switch device is in an inactive state. The RFID switch device may further include a visual indicator displaying a first color if the RFID switch device is in an active state and/or a second color if the RFID switch device is in an inactive state.
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BRIEF SUMMARY OF THE INVENTION
The present invention relates to glass sphere dispensing apparatus for applying small glass spheres or other particles of solid material into and onto a coating material. Particular use of the present invention is in the application of glass spheres simultaneous with the applying of a road marking liquid coating such as paint or thermoplastic on pavements and highways in order to provide night-time luminescence to the marking.
Particle dispensing apparatus of the above nature heretofore devised are deficient in various respects, principally in that they are limited to dispensing of particles of a given size efficiently. If such prior devices were doctored to constrict or narrow the width of the discharge orifice, proportionate reduction of particle flow could not be achieved, resulting in too great a consumption of the material. Such prior art devices, moreover, utilized an integral roller for discharge of particles upon the pavement, making it difficult to efficiently block off flow of particles to selective portions of the roller in instances where two or more separated streams or widths of the particles are to be dispensed. It is, accordingly, the principal object of this invention to provide a novel and improved dispensing apparatus of the character described that obviates the deficiencies of such apparatus heretofore devised.
It is another object of the invention to provide means in a dispensing apparatus for varying the individual width or widths of the stream or streams of glass spheres or other particles being dispensed to coincide with the width or widths of the liquid coating pavement marking.
It is a further object of the invention to dispense the particles proportionately without material waste.
Other objects, features and advantages of the invention will be apparent from the following description when read with reference to the accompanying drawings. In the drawings, wherein like reference numerals denote corresponding parts throughout the several views:
FIG. 1 illustrates, generally, a preferred form of variable width dispenser apparatus embodying the invention;
FIG. 2 is a vertical cross-sectional view of the variable width dispenser showing it in operating position;
FIG. 3 is a vertical cross-sectional view similar to that of FIG. 2, but showing the device in inoperative position; and
FIG. 4 is a perspective view with portions broken away, similar to that of FIG. 1 but showing a modified form of the invention.
DETAILED DESCRIPTION OF THE INVENTION
Referring now in detail to the drawings, reference numeral 10 in FIG. 1 designates, generally, a preferred form of variable width dispenser embodying the invention, the same comprising a holding reservoir or hopper 20 for glass spheres 12 to be dispensed. As best illustrated in FIGS. 1 and 2, the glass spheres 12 slide down an angled plate 22 comprising the hopper or reservoir 20 onto the roller assembly 40 comprising rollers 24, 24a, 24b and 24c, (see FIG. 1), the peripheral outer surfaces of said rollers being appropriately grooved (partially illustrated along the lengths thereof) to receive and evenly space said glass spheres.
The roller assembly 40 is rotated forwardly, as indicated by the arrows, when driven by the drive shaft 26 upon which they are co-axially journalled. As in hereinafter more particularly described, means is provided for selectively attaching one or more of the rollers 24, 24a, 24b, 24c for discharging a corresponding width or widths of glass streams being discharged to conform with the required width and spacing, (if more than one strip is being applied to the pavement). To this end, locking screws or pins 28 are provided in each of the rollers 24, 24a, 24b, 24c for slectively drivingly interconnecting said rollers with respect to the continuously rotating drive shaft 26. It is further to be noted that only the glass spheres 12 that are deposited within the roller grooves will be dispensed since outer portions of said rollers are constricted by closely adjacent flat surface gate 30, which will preferably be somewhat resilient and may be constructed of hard rubber or a rubber-like material.
The roller assembly 40 is fitted snugly from end to end within the housing of the dispenser 10, and is journalled therein below the hopper or reservouir 20 by means of bearings 42 at each end. One end of the drive shaft 26 carries a coupling member 40a for interconnection with a rotary drive mechanism (not illustrated) for actuating the glass sphere dispenser when carried along the roadway by an associated transport cart or the like, (not illustrated).
As illustrated in FIG. 1, 2 and 3, means is provided for selectively securing the roller sleeves 24, 24a, 24b, and 24c to their common drive shaft 26 for depositing preselected widths of stripes upon the coating to be reflectorized by the glass spheres 12 dispensed. To this end, a transverse support bar 36 is fixed within the dispensing housing 10 in spaced, parallel relation with respect to the outside of the roller assembly, said support bar being provided with a plurality of screw opening 38 a sub-plurality of which are in radial alignment, one each, with radial, threaded openings 34 in the rollers 24, 24a, 24b and 24c. Each of the aligned openings 38 carries, circumjacently received therein, a drive member 32 terminating in a kerf or screw-driver bit 32a which is adapted to engage set-screws 28 or the like which may be threadingly received, one each, in openings 34. It will thus be understood that the drive members 32 are each directed perpendicularly with respect to the common axis of the rollers 24, 24a, 24b and 24c, and coaxial with respective openings 28 therein when said roller sections are in such positions that their said openings are opposite their respective drive members, it being understood that said roller sections are independently rotatable about the common drive shaft 26 and are of such length as to provide for various preselected widths of beads to be dispensed. Each drive member 32 has circumjacently received thereon a helical spring 44 constrained between a collar 44a and the inside of the support bar 36. The spring 44 is thus operative to urge the tip or screw driver end 32a of the drive member 32 into the associated roller opening 34. A knob 50 at the outer end of each drive member 32 enables manual turning of the pertaining set screw or pin 28 in or out for engaging or disengaging the associated roller section, the roller section 24b as illustrated in FIG. 1, with respect to the continuously rotating drive shaft 26. With further reference to FIG. 1, roller sections 24a and 24c are illustrated as being secured to the common drive shaft 26 for dispensing glass spheres, whereas roller sections 24 and 24 b are illustrated as being in rest or non-operating position, that is, disconnected from drive shaft 26, their associated drive members 26 having been manually controlled to withdraw the respective set screws or pins 28. In this connection it will be noted that when roller sections are placed in inoperative position, their drive members 32 will be left in engagement with their respective attachment screws or pins under the influence of compression springs 44, thereby constraining said roller sections against inadvertent rotative movement.
FIG. 2 is a cross-sectional view illustrating one of the roller sections in operating position. The roller section 24a is illustrated as being engaged with respect to drive shaft 26 by means of the locking or set screw 28. Glass spheres 12 are deposited in the transverse grooves of the roller 24a and dispensed in sheet form conforming with the length of the roller 24b as the drive shaft 26 is rotated forwardly. The glass spheres 12 slide down the angle plate 22 onto the roller 24b, whence they are carried by gravity to be deposited upon angled deflection plate 52 affixed to the housing in spaced, parallel relation below the roller assembly 40. The plate 52 serves to evenly spread any glass spheres 12 that accumulate in and drop from the recessed attachment screw openings 34. When it is desired to lock a roller section 24, 24a, 24b or 24c on the shaft 26, the corresponding securement or set screw 28 will be rotated or otherwise moved by the drive member 32 for its secure attachment to the shaft 26, whereafter said drive member will be pulled clear of the pertaining roller section, and nut 48 threadingly received on threaded portion 32b of said drive member will be rotated in the inward direction for abutment against the outside of support plate 36 for retaining said drive member in the retracted position.
An entry or access door 54 hinged with respect to the dispenser housing 10 is provided for access to the entire dispensing mechanism, facilitating observation of operation and servicing.
As illustrated in FIG. 2, in operation the dispenser 10 is located and aligned behind the coating apparatus 18 as the glass spheres 12 pass through the space between the gate 30 and the operating roller for gravity feed upon the predeposited liquid coating 14, thereby to produce the reflectorized coating or strip 16 on the highway.
FIG. 3 illustrates, in vertical cross section, one of the roller sections (section 24) in an inoperative position. As illustrated, the pertaining set screw or pin 28 has been disengaged from the common drive shaft 26 by means of the drive member 32. As hereinabove described, the drive member 32, under the influence of compression spring 44, not only serves to adjust the locking screw or pin 28, but remains engaged with the pertaining roller opening 34 to prevent rotative slippage of the roller section under the influence of friction drive, for example. The screw 28 thus always remains in the corresponding radial opening in its roller section. The set screw or pin 28 is driven in or withdrawn either by rotation, as by use of a screw driver as illustrated, or, alternatively, by a slide or spring machanism providing for in and out movement with respect to the roller section. The compression spring 44 rides freely around drive member 32, being constrained between the support bar 36 at one end and the collar member 44a secured to said drive member near its inner end. When the nut 48 is rotated, it frees the drive member so that by holding the knob 40, being affixed to the outer end of said drive member, the operator may push the entire drive member into the opening 34 and thereby remove the screw or pin 28 to disengage from or engage with the common drive shaft 26. When it is desired to lock a roller section 24 on the drive shaft 26, the screw 28 will be rotated or slid securely against the drive shaft 26, the drive member 32 will be pulled clear of the roller section, and the nut 48 rotated to hold the drive member 32 in retracted position.
FIG. 4 illustrates, in a view similar to that of FIG. 1 described above, a modified form of the invention wherein roller sections 24d, 24e and 24f are used for other variations of width of strip and spacing between strips to be deposited if two strips are to be deposited. Thus, as illustrated, if the three roller sections 24d, 24e and 24f are each four inches in width, it is possible to deposit two, 4-inch width ribbons or strips of the glass spheres at a spacing of 4 inches by engaging the end roller sections 24e and 24f and disengaging the central roller section 24e. It will be apparent from the foregoing that simply by selecting for operation particular roller sections 24 from a predetermined group of various customarily used widths, it is possible to evenly dispense glass spheres 12 or the like in one or more ribbons or strips of predetermined width and spacing, as may be required.
It will be obvious to those skilled in the art that this device, while having particular application to road marking equipment, may also be used for the dispensing in predetermined widths of particles of any commensurate size. The invention, in brief, comprises all the embodiments and modifications coming within the scope and spirit of the following claims.
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An apparatus for applying glass spheres or other dry particles at prescribed adjustable widths without wastage of material by gravity feeding such spheres upon a roller assembly comprising a plurality of roller sections selectively engagable for rotation by a continuously driven coaxial drive shaft.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a paint roller for use in connection with hand painting the walls of a house or structure. The paint roller has particular utility in rolling the corner of a wall without getting paint on the adjacent perpendicular surface.
2. Description of the Prior Art
The use of paint rollers are desirable over paint brushes due to their speed, convenience, and the overall results obtained from their use. For example, when painting a room in one's house, the large area of the walls and ceiling can be painted quickly with a paint roller, with only the corners offering some difficulty. Often the painter is slowed down by the need to brush the corners first and then roll up to the brushed area in order to prevent paint on the end of the roller from getting on to the adjacent perpendicular wall. Using both a roller and brush can cause the undesirable visible condition that the texture of the brush is different from that of the roller. Even worse is the case where the two adjoining walls are painted a different color, where it is not acceptable for any of the paint to get on the adjacent wall, ceiling, or other surface.
The use of paint rollers is well known in the prior art, with some addressing the problem of rolling in corners discussed earlier. For example, U.S. Pat. No. 5,412,832 to Irven discloses an edge paint roller that specifically addresses the issue of painting in corners using an angled end portion of the roller. However, the paint roller disclosed in this patent has a fixed built-in angle, and cannot automatically adjust to an application.
U.S. Pat. No. 5,444,891 to Benson and U.S. Pat. No. 5,623,740 to Buns et al. disclose paint rollers that have a removable edge guard, which can be attached for painting corners. However, the thickness of these shields and the gap between the shield and the end of the roller prevents the ability to paint all the way into a corner. This approach also has the further drawback of paint collecting on the shield and eventually spreading on to the adjacent perpendicular surface.
Similarly, U.S. Pat. No. 5,769,769 to Torntore discloses a power roller with an edger device that applies a removable cap on the outer end of the roller to prevent paint from being applied outwardly from the end of the roller. However, there is nothing to prevent the outside surface of this cap or edger device from building up paint, which is then transferred to the adjacent perpendicular surface.
Lastly, U.S. Pat. No. 5,613,264 to Knowles discloses a paint roller corner cover, which covers the end of the roller. However, the purpose of the cover disclosed in this patent is to paint around the corner, as compared to painting up to a corner without getting paint on the adjacent perpendicular wall.
While the above-described devices fulfill their respective, particular objectives and requirements, the aforementioned patents do not describe a paint roller that can automatically adjust for painting in various shaped corners while keeping paint off any adjacent surfaces. It might appear that the outer end of a conventional paint roller could be cut at an angle and used for painting in corners, but as the roller turns this would paint a sinusoidal line in the corner as compared to a desired straight line. Therefore, a need exists for a new and improved paint roller with a simple and inexpensive corner mechanism that can be used for painting large surfaces and corners, without applying paint to the adjacent surfaces. In this regard, the present invention substantially fulfills this need. In this respect, the paint roller according to the present invention substantially departs from the conventional concepts and designs of the prior art, and in doing so provides an apparatus primarily developed for the purpose of applying paint in corners, while keeping paint off adjacent perpendicular surfaces. The present patent discloses a roller that has a simple swivel end cap, which automatically swivels to the required angle for painting corners, thereby preventing the transfer of paint on to any undesired surfaces.
SUMMARY OF THE INVENTION
In view of the foregoing disadvantages inherent in the known types of paint rollers now present in the prior art, the present invention provides an improved paint roller, and overcomes the above-mentioned disadvantages and drawbacks of the prior art. As such, the general purpose of the present invention, which will be described subsequently in greater detail, is to provide a new and improved painting apparatus, which has all the advantages of the prior art mentioned heretofore and additional novel features that result in a paint roller which is not anticipated, rendered obvious, suggested, or even implied by the prior art, either alone or in any combination thereof.
To attain this, the present invention essentially comprises a paint roller that has an outer swivel end that can automatically set to an angle up to about 30-degrees for painting in a corners without applying paint to the adjacent surface. The roller uses a flexible cylindrical paint sock, which is stretched over an outer roller tube and attached at both ends using screw caps so that when the outer angled end of the roller rotates, the length of the roller sock extends in length along the line of contact between the roller and the surface being painted. This keeps the extended portion of the paint sock in the corner, thereby painting a straight line while keeping the remaining portion of the roller's end circumference away from the adjacent surface.
The paint roller is constructed on a rod, which has a straight roller arm portion and a handle portion at right angles to the roller arm portion. A rotatable inner tube for supporting a swivel ball and swivel cap assembly is removably mounted to the roller arm portion. The swivel ball with attached outer swivel cap is attached to the outer end of the inner tube. An outer roller tube is concentrically placed over the inner tube and supported by a rotatable end-cap/screw at the handle end of the roller arm and by a rotatable swivel end-cap and swivel screw at the outer swivel end of the roller. The swivel cap automatically sets to place the outer end cap at an angle up to about 30-degrees relative to a reference perpendicular to the roller arm, thereby providing an outer roller end angle. The cylindrical paint sock is pulled over the outer roller tube, stretched over the two circular end caps and secured at the handle end by an end-cap/screw and at the outer swivel end by a swivel end-cap and swivel screw.
In operation, when the operator presses the end of the roller in a corner, the swivel end adjusts at an angle to place the extended portion of the swivel end cap in the corner, stretching the paint sock in the direction along the roller arm axis. This provides an angle at the end of the roller where all points on the circumference, except for the point of contact, is tilted at an angle away from the adjacent surface. As the rollers and swivel turn, the roller sock is stretched out over the outer swivel circular end cap, thereby applying paint along the corner in a straight line without allowing paint to get on adjacent surfaces.
There has thus been outlined, rather broadly, the more important features of the invention in order that the detailed description thereof that follows may be better understood and in order that the present contribution to the art may be better appreciated.
There are, of course, additional features of the invention that will be described hereinafter and which will form the subject matter of the claims attached.
Numerous objects, features and advantages of the present invention will be readily apparent to those of ordinary skill in the art upon a reading of the following detailed description of presently preferred, but nonetheless illustrative, embodiments of the present invention when taken in conjunction with the accompanying drawings. In this respect, before explaining the current embodiment of the invention in detail, it is to be understood that the invention is not limited in its application to the details of construction and to the arrangements of the components set forth in the following description or illustrated in the drawings. The invention is capable of other embodiments and of being practiced and carried out in various ways. Also, it is to be understood that the phraseology and terminology employed herein are for the purpose of descriptions and should not be regarded as limiting.
As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
It is therefore an object of the present invention to provide a new and improved paint roller that has all of the advantages of prior art paint rollers and none of the disadvantages.
It is another object of the present invention to provide a new and improved paint roller that may be easily and efficiently manufactured and marketed. The simplicity of the ball and cap swivel mechanism of the present invention meets this objective.
An even further object of the present invention is to provide a new and improved paint roller that has a low cost of manufacture with regard to both materials and labor, and which accordingly is then susceptible of low prices of sale to the consuming public, thereby making such paint rollers economically available to the buying public. Again, the simplicity of the ball and cap swivel mechanism of the present invention meets this objective.
Still another object of the present invention is to provide a new paint roller that provides in the apparatuses and methods of the prior art some of the advantages thereof, while simultaneously overcoming some of the disadvantages normally associated therewith.
These together with other objects of the invention, along with the various features of novelty that 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 the specific objects attained by its uses, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated preferred embodiments of the invention.
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:
FIG. 1 is a drawing of the preferred embodiment of the paint roller constructed in accordance with the principles of the present invention.
FIG. 2 is a longitudinal cross-sectional view of the paint roller of the present invention illustrating how the swivel end of the roller can be tilted at an angle for painting in corners.
FIG. 3 is a circumferential cross-sectional view of the paint roller of the present invention.
FIG. 4 is a drawing showing the assembly of the paint roller apparatus of the present invention.
FIG. 5 is an application drawing illustrating the painting of a straight line along the edge of a window using the paint roller of the present invention.
FIG. 6 is a perspective drawing of a second embodiment of the paint roller constructed in accordance with the principles of the present invention.
FIG. 7 is a perspective drawing shoving a cover plate/roller guide used with the paint roller of the second embodiment of the present invention.
The same reference numerals refer to the same parts throughout the various figures.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to the drawings of FIGS. 1-5 a preferred embodiment of the paint roller of the present invention is shown and generally designated by the reference numeral 10 . These figures illustrate and describe the new and improved paint roller 10 of the present invention for quickly rolling paint into corners. Particularly, FIG. 1 shows the assembled paint roller 10 , FIGS. 2 and 3 show longitudinal and circumferential cross-sectional drawings, respectively, of the paint roller, FIG. 4 shows the paint roller assembly, and FIG. 5 illustrates the application of the paint roller.
In FIG. 1 , the paint roller 10 has a flexible roller sock 12 , for holding and dispensing paint, pulled over an outer cylindrical roller tube, which is supported by rotatable circular end-caps 16 , 18 . The assembly is held together by means of screws, at each end of the roller, which also are used to secure the flexible sock in place. The outer end of the roller is swiveled at an angle, allowing paint to be applied in corners along a straight line. Roller socks 12 having various fiber surfaces can be used to obtain a desired paint texture. The roller assembly is removable mounted on the roller arm portion 14 of a metal rod, which is bent to provide a handle portion perpendicular to the roller. The handle portion of the metal rod is attached to a handle 20 .
More particularly, as shown in FIGS. 2 and 3 , the paint roller has a rotatable inner tube 22 , with a built-in swivel ball 24 and swivel block 26 assembly mounted on the outer end, which is removably pushed over the roller arm 14 and secured by means of a roller arm snap lock 28 . A concentric outer roller tube 30 is placed over the inner tube 22 and rotatably supported by a circular end-cap 17 and end-cap screw 16 at the handle end of the roller and by a swivel end-cap 18 and separate swivel screw 32 at the opposite outer end of the roller. The flexible paint sock 12 is stretched over the outer tube 30 , pulled over the circular end-caps 17 , and swivel end-cap 18 , and secured at each end of the roller by placing the sock under the screws 16 ; and 32 .
FIG. 4 shows the paint roller 10 assembly starting with the metal roller arm 14 and attached handle 20 with a rotatable circular end-cap 17 and end-cap screw 16 placed over the roller arm to support one end of the outer roller tube 30 . The inner tube 22 is then placed over the roller arm 14 and rotatable attached by means of the end-cap screw 16 being placed through the circular end-cap 17 and threaded into the inner tube bushing 23 mounted in the handle end of the inner tube 22 . Next, the outer roller tube 30 is placed concentrically over the inner tube 22 , where it is supported at the handle end by the circular end-cap 17 . The swivel ball 24 and attached swivel block 26 are then snapped on to the roller arm snap lock 28 on the outside end of the roller arm 14 away from the handle. A flexible roller sock 12 is then stretched over the outer roller tube 30 and the outside end is secured by placing the swivel end-cap cap 18 in the end of the outer tube 30 , folding the flexible roller sock 12 over the swivel end-cap 18 and securing with swivel screw 32 being threaded into the swivel block 26 . Additionally, a snap-on protective end-cover plate 40 can be utilized to keep paint from accumulating at the end of the roller.
In operation, when the operator presses the roller against the surface to be painted, the swivel block 26 swivels to an angle 38 ( FIG. 2 ) up to about 30-degrees. This stretches the flexible sock 12 by an amount 36 over the extended edge 34 of the swivel end-cap 18 . As the rollers turn, the swivel end-cap 18 also turns, always at the set angle, keeping the extended portion of the flexible sock in the corner, thereby painting a straight line along the corner.
FIG. 5 is an application drawing illustrating the painting of a straight line along the edge of a window 42 using the paint roller 10 of the present invention.
FIG. 7 is a perspective drawing showing a square or rectangular cover plate/roller guide used with the paint roller of the second embodiment of the present invention.
FIG. 6 is a perspective drawing of a second embodiment of the paint roller constructed in accordance with the principles of the present invention. In this case, snap-on end-caps 52 , 60 are used to hold the outer cylindrical roller tube 30 and flexible roller sock 12 in place at both ends of the roller. This embodiment of the paint roller is assembled by placing the rotatable snap-on end cap 52 on the roller arm 14 and then sliding the inner tube 22 on to the roller arm 14 . The swivel end-cap 54 is connected to the exposed roller arm snap lock 28 at the outside end of the roller arm 14 away from said handle end of the roller rod 14 . The outer cylindrical roller tube 30 is then placed concentrically over the inner tube 22 . The flexible roller sock 12 is then stretched over the outer cylindrical roller tube 30 and the swivel end-cap 54 and secured at the outside end by means of a second snap-on end cap 60 . Optionally, a rectangular cover plate/roller guide 62 can be snapped into the end-cap 60 for guiding the paint roller along door frames and other straight borders.
While a preferred embodiment of the paint roller has been described in detail, it should be apparent that modifications and variations thereto are possible, all of which fall within the true spirit and scope of the invention. With respect to the above description then, it is to be realized that the optimum dimensional relationships for the parts of the invention, to include variations in size, materials, shape, form, function and manner of operation, assembly and use, are deemed readily apparent and obvious to one skilled in the art, and all equivalent relationships to those illustrated in the drawings and described in the specification are intended to be encompassed by the present invention. For example, any suitable sturdy material such as metal, plastic, or hard rubber may be used in fabricating the roller tubes of the paint roller apparatus.
Therefore, the foregoing is considered as illustrative only of the principles of the invention. Further, since numerous modifications and changes will readily occur to those skilled in the art, it is not desired to limit the invention to the exact construction and operation shown and described, and accordingly, all suitable modifications and equivalents may be resorted to, falling within the scope of the invention.
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A paint roller having a stretchable cylindrical paint sock, which is pulled over both ends of an outer roller tube and attached by screw-cap means, with the outer end being stretched over a swivel end-cap capable of providing a roller end angle up to about 30-degrees, thereby allowing paint to be dispensed in a corner without applying paint to the adjacent perpendicular surface. In operation, as the roller turns, the paint sock is outwardly stretched over the swivel end-cap, extending the roller sock line of contact with the wall surface, thereby continuously applying paint in a straight line along the corner.
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RELATED APPLICATIONS
This application is a divisional of U.S. patent application Ser. No. 14/293,128 filed Jun. 2, 2014, which hereby claims the benefit of and priority thereto under 35 U.S.C. §§119, 120, 363, 365, and 37 C.F.R. §§1.55 and 1.78, which is a divisional of U.S. patent application Ser. No. 13/559,103 filed Jul. 26, 2012 now U.S. Pat. No. 8,790,410, the benefit of and priority thereto claimed under 35 U.S.C. §§119, 120, 363, 365, and 37 C.F.R. §1.55 and §1.78, and both are incorporated herein by this reference.
FIELD OF THE INVENTION
The invention relates to tibial tuberosity advancement procedures in canines.
BACKGROUND OF THE INVENTION
During the tibial tuberosity advancement procedures in canines, the tibia is cut just behind the tibial tuberosity and the tibial tuberosity is advanced to achieve a perpendicular relationship between the tibial plateau slope and the patella tendon. A titanium or stainless steel implant (also called a cage or spacer) is placed between the advanced tibial tuberosity and the tibia and a plate is used to secure the tibial tuberosity to the tibia.
Over time, bony growth forms in and around the spacer. In the case of an infection or other problem, it can be very difficult to remove the spacer. As many as one in ten tibial tuberosity advancement procedures result in infection or rejection of the spacer implant.
Biocompatible and biodegradable materials are known for use in implants but an implant made of a plastic biodegradable material and designed like prior art metal implants may not be strong enough to maintain the tibial tuberosity in the advanced state as the canine recovers and becomes active. Injection molding limitations also prevent manufacturing a plastic implant designed like the prior art metal tibial tuberosity implant.
SUMMARY OF THE INVENTION
In one or more aspects of a preferred embodiment of the invention, a trimable tibial tuberosity advancement implant is molded using a biocompatible, biodegradable material so that in case of infection or the like only the metal clip portion of the implant need be removed (using, for example, minimal invasive surgery techniques). And yet, the implant spacer body is structurally sound until decomposition and bony ingrowth occurs between the advanced tibial tuberosity and the tibia.
Featured is a tibial tuberosity advancement implant comprising a spacer body made of biocompatible, biodegradable material. A main section has at least one bony growth orifice therethrough. At least one fin extends from the main section by at least one connector. A clip is engageable with the main section and includes spaced screw holes for securing the spacer body to the advanced tibial tuberosity and the tibia when the spacer body is implanted.
The clip is usually made of stainless steel or titanium. It preferably includes spaced ears each having a screw hole and upper and lower spaced spring arms interconnecting the spaced ears. Each spring arm then includes an outwardly curved portion including a central cut out and the spacer body main section slot includes spaced upper and lower tabs each received in a cut out of the clip.
The typical biocompatible, biodegradable material used includes polyglycolic acid and/or polylactic acid. Preferably, the spacer body main section includes at lease two spaced bony growth orifices, the spacer body main section has an isosceles trapezoid cross sectional shape, the fins are angled inwardly rendering the top of the implant longer and wider than the bottom and there is a top and a bottom cuttable connector for each fin to customize the length of the implant.
One example of a tibial tuberosity advancement implant in accordance with the invention includes a spacer body made of biocompatible, biodegradable material and including a main section having an isosceles trapezoid cross sectional shape with at least one bony growth orifice therethrough and a proximal slot. Inwardly angled fins extend from the main section rendering the top of the implant longer than the bottom. A clip is slideable into the proximal slot of the main section and includes spaced screw holes for securing the spacer body to the advanced tibial tuberosity and the tibia.
Another tibial tuberosity advancement implant made of biodegradable material includes a proximal face, a slot behind the proximal face for a metal clip, distal spaced cuttable fins, and bony growth orifices in a main body section between the proximal face and the distal fins. Typically, the implant is longer and wider at the top than at the bottom and the body section is configured as an approximation of a concrete block.
This invention also features a method comprising advancing the tibial tuberosity of a canine, implanting a biodegradable spacer to retain the tibial tuberosity in an advanced position, fixing the implant using a metal non-biodegradable clip connected to the spacer, promoting bony in-growth and degradation of the biodegradable spacer, and removing the metal non-biodegradable clip in the case of an infection or other problem.
The subject invention, however, in other embodiments, need not achieve all these objectives and the claims hereof should not be limited to structures or methods capable of achieving these objectives.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWINGS
Other objects, features, and advantages will occur to those skilled in the art from the following description of a preferred embodiment and the accompanying drawings, in which:
FIG. 1 is a schematic three dimensional side view of an implant between an advanced tibial tuberosity and the tibia of a canine;
FIG. 2 is a schematic three dimensional side view of an example of a preferred version of a biodegradable implant in accordance with the invention;
FIG. 3 is a schematic bottom view of the implant shown in FIG. 2 ;
FIG. 4 is a schematic front view of an example of the clip portion of an implant in accordance with the invention;
FIG. 5 is a schematic front view of the implant of FIGS. 2-3 with the clip of FIG. 4 inserted therein.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows implant 10 used in a tibial tuberosity advancement procedure in accordance with the invention along with plate 12 . Implant 10 is preferably injection molded using a biocompatible, biodegradable plastic material such as polyglycolic acid and/or polylactic acid. It may also include bone growth proteins and the like. Initially, implant 10 is structurally sound and correctly spaces the advanced tibial tuberosity 14 from the tibia 16 while the canine is recuperating and thereafter active. The implant has features which promote bony growth between the advanced tibial tuberosity and the tibia which over time fills space 18 . Thereafter, the implant degrades and dissolves.
Thus, in the case of infection, rejection, or some other problems requiring removal of the implant, all that need be removed are the two screws and the metal clip portion of the implant. Minimally invasive surgical techniques can be used. In the prior art, as explained in the Background section above, the titanium or stainless steel implant was secured in the space 18 by bony growth and was very difficult to remove. Minimally invasive surgical techniques could not be used.
One preferred version of the implant is shown in FIGS. 2-5 . Structurally strong spacer body 20 , FIGS. 2-3 , is made of biocompatible, biodegradable material and includes main section 22 and distal fins 24 a and 24 b . Main section 22 has proximal slot 26 for clip 28 , FIG. 4 . Main section 22 also has bony growth orifices 30 a and 30 b therethrough designed to promote bone growth therein and around the implant. Section 22 somewhat mimics the configuration of a concrete block. Spaced fins 24 a and 24 b are also designed to promote bony growth in the space between main section 22 and fin 24 a and in the space between fin 24 a and fin 24 b . Also, top and bottom connectors 32 a and 32 b (connecting fin 24 a to main section 22 ) and top and bottom connectors 32 c and 32 d (connecting fin 24 b to fin 24 a ) can be cut, as desired, to shorten the length of the implant for different size canines.
With both fins intact, the implant is 27 mm long; with fin 24 b cut off, the implant is 24 mm long; and with both fins 24 a and 24 b cut oft the implant is 21 mm long. In this way, one mold is effectively able to produce three different length implants. Other sizes are possible. Different width cages are possible.
Fins 24 a and 24 b as well as distal wall 36 of main section 22 are angled inwardly at 25° with respect to vertical resulting in an implant with a shorter bottom surface 40 a and a longer top surface 40 b , FIGS. 3 and 5 . Spacer body main section 22 also has an isosceles trapezoid cross sectional shape as does proximal face 50 (see FIG. 5 ) and fins 24 a and 24 b . As a result, the top of the implant is wider and longer than the bottom. The implant thus conforms to the shape of the space between the tibia and the advanced tibial tuberosity.
In one example, the implant was 27 mm long at the top, 22 mm long at the bottom, 9 mm wide at the top, and 7 mm wide at the bottom. Fin connectors 32 were 2.1 by 6 by 1.2 mm. Slot 26 behind proximal face 50 was 1.2 mm wide.
Preferably, stainless steel or titanium 1 mm thick clip 28 , FIG. 4 has spaced ears 70 a and 70 b each with a screw hole 72 b and 72 b , respectively. Curved upper 74 a and lower 74 b spring arms interconnect the ears 70 . Each spring arm 74 includes central cut out 76 a , 76 b that receive therein centered tabs connecting proximal face 50 , FIGS. 2-3 to main section 22 . Bottom tab 78 a is shown in FIG. 3 and top tab 78 b is shown in FIG. 2 . The clip spring arm cutouts are wider than the thickness of the tabs so clip 28 can be rotated slightly with respect to the spacer body. When clip 28 is inserted into spacer body slot 26 , spring arms 74 a and 74 b are compressed towards each other. After insertion, the upper and lower tabs retained in the cutouts retain the clip in the spacer body.
Although specific features of the invention are shown in some drawings and not in others, this is for convenience only as each feature may be combined with any or all of the other features in accordance with the invention. The words “including”, “comprising”, “having”, and “with” as used herein are to be interpreted broadly and comprehensively and are not limited to any physical interconnection. Moreover, any embodiments disclosed in the subject application are not to be taken as the only possible embodiments.
In addition, any amendment presented during the prosecution of the patent application for this patent is not a disclaimer of any claim element presented in the application as filed: those skilled in the art cannot reasonably be expected to draft a claim that would literally encompass all possible equivalents, many equivalents will be unforeseeable at the time of the amendment and are beyond a fair interpretation of what is to be surrendered (if anything), the rationale underlying the amendment may bear no more than a tangential relation to many equivalents, and/or there are many other reasons the applicant can not be expected to describe certain insubstantial substitutes for any claim element amended.
Other embodiments will occur to those skilled in the art and are within the following claims.
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A tibial tuberosity advancement implant and method includes a spacer body made of biocompatible, biodegradable material and having a main section with at least one bony growth orifice therethrough and at least one fin extending from the main section by at least one connector. A metal clip is engageable with of the spacer body main section and includes spaced screw holes for securing the spacer body to the advanced tibial tuberosity and the tibia when the implant is placed in the space between the advanced tibial tuberosity and the tibia.
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This application is a division of application Ser. No. 07/981,014, filed Nov. 24, 1992, now U.S. Pat. No. 5,349,505.
BACKGROUND OF THE INVENTION
The field of the present invention is underwater lighting for pools and the like.
Swimming pools are subject in most jurisdictions to restrictive codes directed to the avoidance of electrical shock. Most typically, all conductive elements associated with the pool are to be grounded to a conductive net provided about the pool. This includes lighting fixtures. Additionally, powered fixtures are to be grounded to the electrical panel from which current is obtained for running the fixture such as a pool light.
A main pool light typically includes a conductive forming shell which is integrally associated with the structure of the pool and is electrically grounded to the pool grounding net. This conductive forming shell forms a niche in the side of the pool for receipt of a light housing. Such shells are typically displaced from an associated light housing with free water flow into the niche defined by the shell. The water admitted between the housing and the shell is used to cool the light.
Typical light housings are sealed with a lamp contained therein, a lens covering a front opening and a bezel about the lens which covers the periphery of the niche for aesthetic purposes and mounts the housing to the forming shell. The housings are typically conductive and have a ground wire extending as part of a cable through the forming shell and to the junction box. The conductive housing is also in electrical communication with tile forming shell through the bezel and in turn with the pool grounding net.
Failure considerations in defining codes include the prospect of the lens being broken. Under such circumstances, electrical potential lines in the pool water are understood to form fields much like magnetic field lines. The metallic housing, bezel and forming shell all act to constrain the electric field and prevent shock to anyone nearby. The grounding through the net is further intended to prevent shock when someone comes in contact with another conductive element in the pool, such as a ladder or drain.
SUMMARY OF THE INVENTION
The present invention is directed to a wet niche light for a pool.
In a first aspect of the present invention, a nonconductive housing is employed within the wet niche. A grounded conductive shield extends over each of two lamp sockets. The shield provides containment for any electrical fields which may be established around the sockets if water invades the housing.
In another aspect of the present invention, the conductive shield of the first aspect may act as a reflector. A double-ended lamp employed in the sockets may be configured to fall from electrical contact if broken.
In a further aspect of the present invention, a nonconductive forming shell is associated with a lamp to define a pool niche. A conductive ring is employed about the front opening of the forming shell and also extends rearwardly as a strap to a terminal through the nonconductive forming shell. This makes grounding of the conductive ring to the pool net possible. This arrangement further provides confinement of any electric field as well as a conventional terminal for shell grounding.
In yet a further object of the present invention, a light is constructed with a housing, a lens across the front opening of the housing and a bezel configured to receive the lens and to attach to the housing for sealed engagement through the means of resilient clips. A uniform seal is thus insured without overstressing components or requiring metallic, conductive materials.
In further aspects of the present invention combinations of the foregoing principles are contemplated.
Accordingly, it is an object of the present invention to provide an improved wet niche light. Other and further objects and advantages will appear hereinafter.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a front view of a light of the present invention.
FIG. 2 is a vertical cross-sectional view of the light including the housing and forming shell.
FIG. 3 is a front view of the housing with the bezel and lens removed.
FIG. 4 is a back view of the lens and bezel assembly.
FIG. 5 is a cross-sectional side view of the bezel.
FIG. 6 is a perspective view of the conductive shield.
FIG. 7 is a side view of a rigid grounding conductor.
FIG. 8 is a back view of the rigid grounding conductor.
FIG. 9 is a side view of the conductive ring.
FIG. 10 is a front view of the conductive ring.
FIG. 11 is a diagrammatic view of a pool illustrating light rays from a fixture of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Turning in detail to the drawings, FIG. 1 illustrates a niche light for swimming pools as it would be viewed from the pool. A lens 10 is illustrated to be surrounded by a bezel 12. The construction of the light is better illustrated in FIG. 2 as further including a nonconductive forming shell 14 and a nonconductive housing 16. The forming shell 14 defines a niche 18 having a front opening lying substantially in a vertical plane as it is arranged in the pool. Threaded ports 20 and 22 may be plugged or may include grommets for receipt of electrical conduit extending from the pool to a junction box. The front opening of the nonconductive forming shell 14 is generally circular.
FIGS. 9 and 10 provide the details of a conductive ring 24 which is pressed into the inner periphery of the nonconductive forming shell 14 at the front opening. Anchors 26 press outwardly against the nonmetallic shell and lock the conductive ring 24 in place. A strap 28 extends rearwardly into the shell 14 from the conductive ring 24. A terminal 30 is bolted to the shell 14 for attachment to the grounded pool net.
The nonconductive housing 16 is water tight but for a front opening also lying in a vertical plane as positioned in the pool. The housing 16 is spaced from the nonconductive forming shell 14 in order that water may fully surround the housing 16 and provide cooling thereto.
The housing includes a foot 32 which extends downwardly from the bottom thereof. At the upper end of the housing 16, a tab 33 having a hole therethrough provides for receipt of a fastening bolt 34. The foot 32 and the bolt 34 engage a stop 36 and a threaded hole 38, respectively, arranged on the conductive ring 24. As the conductive ring 24 is securely positioned within the shell 14 by means of the anchors 26, the stop 36 and hole 38 securely retain the housing 16 and yet allow the bolt 34 to be removed for relamping.
The interior of the housing 16 includes a channel 40 extending partially about the cavity. At one end of the channel 40, a potting cavity 42 is positioned to receive conductive elements from externally of the housing. Two socket cavities 44 and 46 are provided on either side of the main cavity of the housing 16. In a first socket cavity 44, a retaining slot is defined by two inwardly extending flanges 48 and 50 spaced to receive a square positioning flange 51 on a socket 52. The other socket cavity 46 also includes inwardly extending flanges 54 and 56 which are spaced further apart than the flanges 48 and 50 so as to receive a square positioning flange 59 on a socket 58 and a spring 60. The spring 60 is placed in compression so as to bias the socket 58 inwardly within the housing 16. The sockets 52 and 58 are aligned to define an axis therebetween for receipt of a double ended lamp 62. The lamp is to be of sufficient length to place the spring 60 in added compression through movement of the socket 58 to accommodate the lamp. The sockets 52 and 58 are preferably designed so that the double ended lamp 62 is held in place by compression and does not have the ends of the lamp held in frictional engagement. In this way, if the lamp 62 is ever broken, the two or more fragments will fall from the sockets 52 and 58 so as to cease to conduct electricity under such a failure mode.
Within the housing 16, a first conductor 64 extends from the socket 52 around the channel 40 to the potting cavity 42. A second conductor 66 extends from the socket 58 into the potting cavity 42. In the conductor 64, a thermostat 67 is positioned which ceases to conduct above a selected temperature. Consequently, if the lamp is on without water around the housing 16, the accumulated heat will cause the thermostat to actuate and turn off the lamp.
A conductive shield 68 is positioned within the housing 16 so as to shield the sockets 52 and 58. The conductive shield may be considered as three portions with two outward portions 70 and 72 covering the sockets and a central, reflective portion 74. The outward, socket portions 70 and 72 each extend over a socket and then extend inwardly within the housing 16 to meet the reflective portion 74 located behind the lamp 62. Holes 76 and 78 provide for placement of the double ended lamp 62. The conductive shield 68 may conveniently be of highly reflective metal sheet so as to reflect a maximum amount of the light emanating from the lamp 62 outwardly into the pool. A connector 80 forming part of the conductive shield 68 extends to the potting cavity 42 where it is coupled with a ground conductor 82.
Extending from the potting cavity 42 outwardly to the hole in the housing 16 for receiving the bolt 34 is a rigid ground conductor 84. This rigid conductor 84 is connected at one end to the connector 80. This connection in turn provides a ground to the ground conductor 82 extending to the junction box and, ultimately, to an electrical panel. At its other end, the rigid conductor 84 is associated with the bolt 34 that is threaded into the hole 38 of the conductive ring 34. Thus, a separate grounding to the pool net is provided. Holes are provided through the wall of the housing 16 at the potting cavity 42 in order that the rigid conductor 84 may pass therethrough as well as a conduit containing the conductors 64 and 66 and the grounded conductor 82. A potting body 86 is then poured and solidified into the potting cavity 42 as well as the channel 40.
The bezel 12 is best illustrated in FIGS. 4 and 5. The bezel 12 includes a circular body 88 having a central hole 90 therethrough. A rearwardly extending flange 92 which is cylindrical in form defines a seat for the lens 10. Outwardly of the flange 92 are flange segments 94 which extend further rearwardly on the bezel 12 to further define the seat for the lens 10 which fits therein. In the circular body 88, circulation holes 96, as best seen in FIG. 1, communicate with the interior of the shell 14 defining the niche.
Also extending rearwardly from the bezel 12 are clips 98. Each clip 98 is a resilient leg extending rearwardly on the bezel with an interlocking portion 100. The housing 16 includes outwardly extending flanges 102 to which the interlocking portions 100 may resiliently pass over when the bezel 12 is pressed against the front of the housing 16 and come into interlocking engagement.
The front of the housing 16 includes a sealing channel 104 which contains an O-ring 106. The O-ring 106 is compressed by the lens 10 when the bezel and lens assembly is positioned and interlocked on the housing 16.
The lens 10 is preferably planar with means for further refracting light in other than on upward direction, e.g., horizontally and downwardly to this end, vertically arranged dispersion ribs 108 are on the back side of the lens 10. The vertically arranged ribs 108 spread light horizontally from the lamp 62. A smooth circular rim 110 about the lens 10 provides a seat against the O-ring 106. A strip of opaque material extends 180° about the junction between the main portion of the lens 10 and the rim 110 to prevent a vertical dispersion of light at that junction.
Turning to FIG. 11, an optical system is illustrated which prevents the light image from the wet niche light from directly being observed above the pool. The pool wall 112 is schematically illustrated as supporting a housing 16. Light from the lamp 62 is shown to be refracted through the lens 10 into the pool. The lamp 62 is positioned rearwardly in the housing 16 away from the lens 10 to an extent that the maximum upward angle of light exiting from the lens 10 is below the critical angle of total reflection at the water-to-air boundary 114. The use of a planar lens and only vertical ribs allows for horizontal but not vertical dispersion of the light through the lens to insure further the appropriate angle. To further reduce creation of an image of the light on the surface, the lower portion 116 of the interior of the housing 16 may be painted black or otherwise configured such that light does not reflect directly from the lamp 62 onto the lower surface of the interior portion of the housing and through the lens.
An angle of incidence is the angle a ray makes with a normal to the surface at the point of intersection of the ray with that surface. For a water-to-air boundary, an angle of incidence of 48.5° or more will cause total reflection of the light at that surface. To simply meet this critical angle of total reflection, light emanating from the lens 10 placed at 90° to the surface of the water is to have an upward angle of refraction, i.e., the angle between a light path extending upwardly from the lens 10 and a horizontal plane including the point of exit of the light path from the lens 10, which is no more than 41.5°. Because of the air-to-glass and glass-to-water boundaries at the lens 10, the upward angle of incidence from the lamp 62, i.e., the angle between a light path extending upwardly from the lamp 62 and a horizontal plane including the source of light from the lamp 62, to any portion of the lens 10 which can transmit light, is not to exceed slightly over 62°. These angles assume a flat water surface.
At the same time, the principal objective is to disperse light into the pool. With the vast majority of pools, light dispersion from a single pool light is virtually complete throughout the pool even with a maximum angle of incidence on the lens 10 from the lamp 62 of much less than the critical angle of 62°.
To reduce flashing of light from the pool resulting from waves and ripples, the upward angle of incidence by light from the lamp 62 against the lens which can pass through the lens 10 has been reduced to a maximum of approximately 42°. A 42° maximum upward angle of incidence from the lamp 62 to the lens 10 results in a 30° maximum upward angle of refraction at the glass-to-water boundary. This gives a minimum angle of incidence at the water-to-air surface of the pool, when flat, of 60°, 11.5° over the critical angle of total reflection. Fixture misalignment and some waves are thereby accommodated. The maximum downward and lateral angles of refraction may intentionally far exceed the maximum upward angle to insure full illumination of the pool. This configuration has been found to provide adequate light dispersion in the conventional swimming pool, eliminate viewing of an image of the pool light from above the water surface and reduces flashing at surface ripples to an aesthetically pleasing effect. The effect generally appears to be light flashes at the surface rather than the image of a pool light below the surface.
Thus, an improved wet niche pool light is here described. While embodiments and applications of this invention have been shown and described, it would be apparent to those skilled in the art that many more modifications are possible without departing from the inventive concepts herein. The invention, therefore is not to be restricted except in the spirit of the appended claims.
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A wet niche light having a nonconductive forming shell 14 with a nonconductive housing 16 mounted therein. A double ended lamp is fixed within the housing in sockets which do not retain the lamp in friction engagement but rather hold the lamp by axial compression. A conductive reflector extends over the sockets and is grounded externally. A planar lens having vertical ribs is positioned within a bezel that attaches to the forward side of the housing by means of resilient clips. The nonconductive forming shell includes a conductive ring about the front opening of the shell with a conductor extending rearwardly for coupling with a pool grounding net. The lamp is positioned far enough within the housing such that no direct light from the lamp will strike the surface of the water in the pool at less than the critical angle of total reflection. The interior of the housing includes a lower portion painted in black such that light will not be reflected therefrom to strike the water surface at an angle less than the critical angle of total reflection.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] The current application claims the benefit of and priority to Israel Patent Application No. 194519, filed Oct. 5, 2008, and incorporated herein by reference in its entirety.
FIELD OF THE INVENTION
[0002] The present invention relates to the field of pelvic floor reconstruction. In particular, the present invention relates to the field of pelvic floor reconstruction using implants.
BACKGROUND OF THE INVENTION
[0003] Pelvic organ prolapse (POP) is a common female problem that can have a profound impact on a woman's quality of life.
[0004] The organs in the pelvic cavity, uterus, vagina, bladder and rectum, are held in place by a web of muscles and connective tissues that act much like a hammock. When these muscles and tissues become weakened or damaged, one or more of the pelvic organs shift out of normal position and literally “fall” into the vagina.
[0005] Prolapse surgical reconstruction is performed through the vagina. During the procedure, the surgeon repositions the prolapsed organs, securing them to surrounding tissues and ligaments, and may use a synthetic non-absorbable polypropylene mesh implant.
[0006] However, the prior art surgical procedures penetrate the patient from several directions.
[0007] As well, they do not provide reliable anchoring of the mesh implant.
[0008] It is an object of the present invention to provide a reliable anchoring of the mesh implant.
[0009] Other objects and advantages of the invention will become apparent as the description proceeds.
SUMMARY OF THE INVENTION
[0010] The following embodiments and aspects thereof are described and illustrated in conjunction with systems, tools methods, and so forth, which are meant to be merely illustrative, not limiting in scope.
[0011] In one aspect, the present invention may be directed to a needle for surgical threading of a strap of an implant through a tissue, the needle comprising:
a trap for trapping the strap to the needle, while the needle may be at the accessible side of the tissue; a tip for threading the trapped strap from the accessible side to the opposing side; and a mechanism for releasing the trap, the mechanism driven from the accessible side of the tissue, thereby allowing return of the tip to the accessible side of the tissue while abandoning the strap at the threaded point, thus performing threading from the accessible side of the tissue.
The trap may comprise:
a niche, for inserting an end of the strap of the implant; and a rod, for grasping the end of the strap.
The niche may be located near the tip.
[0018] The end of the strap may comprise a looped end for inserting the rod thereinto.
[0019] According to another embodiment the rod is capable of applying physical force on the end of the strap towards the limiting wall thereof in the niche.
[0020] The mechanism for releasing the trap may be manually driven.
[0021] The mechanism for releasing the trap may comprise a cable, driven from the accessible side of the tissue, for removing the rod from the end of the strap.
[0022] The needle may further comprise an arm for driving the mechanism, the arm located outside the surgical area.
[0023] In another aspect, the present invention is directed to an anterior implant comprising:
at least two first straps for threading thereof into the arcus tendineous fascia pelvic (ATFP) ligaments; at least two second straps for threading thereof into the sacrospinous (SS) ligaments; and a loop between the second straps for anchoring thereof to the cervix.
[0027] The anterior implant may be used for reconstructing the organs selected from the group including: prolapse of the urinary bladder, the colon, the small intestine.
[0028] The anterior implant may further comprise spaces for reducing weight of the implant.
[0029] In another aspect, the present invention is directed to a posterior implant comprising:
at least two straps for threading thereof into the sacrospinous (SS) ligaments; a first loop between the straps for anchoring thereof to the cervix; and a second loop at the side opposing the straps, the second loop for anchoring thereof to the perineal body.
[0033] The posterior implant may be used for reconstructing the organs selected from the group including: the colon, the small intestine, the uterus.
[0034] The posterior implant may further comprise spaces for reducing weight of the implant.
[0035] In another aspect, the present invention is directed to a method for using a needle to thread a strap through a surface, the method comprising the steps of:
trapping an end of the strap while the needle is at the accessible side of the surface tissue; threading the needle, together with the trapped strap, through the surface, from the accessible side of the surface; releasing the trap, such that the driving of release is from the accessible side; and returning the needle to the accessible side while abandoning the strap at the threaded point, thereby performing threading from the accessible side.
[0041] The trapping of the end of the strap may comprise the steps of:
inserting the end of the strap into a niche; and grasping the end of the strap.
[0044] Grasping of the end of the strap may comprise the step of inserting a rod of the needle into a looped end of the strap.
[0045] According to another embodiment grasping of the end of the strap may comprise the step of applying physical force on the end of the strap towards the limiting wall thereof in the niche.
[0046] Releasing the trap may comprise the step of removing the rod from the end of the strap.
[0047] In another aspect, the present invention is directed to a method for installing an anterior implant, the method comprising the steps of:
threading at least two first straps of the implant into the arcus tendineous fascia pelvic (ATFP) ligaments; threading at least two second straps of the implant into the sacrospinous (SS) ligaments; and anchoring a loop between the second straps to the cervix.
[0051] In another aspect, the present invention is directed to a method for installing a posterior implant, the method comprising the steps of:
threading at least two straps of the implant into the sacrospinous (SS) ligaments; anchoring a first loop between the straps, to the cervix; and anchoring a second loop at the side opposing the straps, to the perineal body.
[0055] In addition to the exemplary aspects and embodiments described above, further aspects and embodiments will become apparent by reference to the figures and by study of the following detailed description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0056] The objects and features of the present invention will become apparent from the following detailed description considered in conjunction with the accompanying drawings, in which:
[0057] FIG. 1 illustrates an anterior implant according to one embodiment of the present invention.
[0058] FIG. 2 illustrates an anterior view of the pelvic area before installing the anterior implant.
[0059] FIG. 3 illustrates the view of FIG. 2 after installing the anterior implant.
[0060] FIG. 4 illustrates a posterior implant according to one embodiment of the present invention.
[0061] FIG. 5 illustrates the view of FIG. 2 after installing the posterior implant.
[0062] FIG. 6 illustrates the head of a needle for threading the straps of the implants, according to one embodiment of the present invention.
[0063] FIG. 7 illustrates the first step of threading the straps of the implants, using the needle of FIG. 6 .
[0064] FIG. 8 illustrates the second step of threading the straps of the implants, using the needle of FIG. 6 .
[0065] FIG. 9 illustrates the third step of threading the straps of the implants, using the needle of FIG. 6 .
[0066] FIG. 10 illustrates the fourth step of threading the straps of the implants, using the needle of FIG. 6 .
[0067] FIG. 11 illustrates the needle of FIG. 6 and its operation.
[0068] FIG. 12 illustrates the operation of the needle of FIG. 6 from the aspect of the surgeon's access to the pelvic area.
[0069] FIG. 13 illustrates the operation of the needle of FIG. 6 in the aspect of FIG. 12 , to another ligament.
[0070] It is to be understood, however, that the drawings are designed solely for purposes of illustration and not as a definition of the limits of the invention, for which reference should be made to the appended claims. It should be further understood that the drawings are not necessarily drawn to scale and that, unless otherwise indicated, are merely intended to conceptually illustrate the structures and procedures described herein. Reference numerals may be repeated among the figures in order to indicate corresponding or analogous elements.
DETAILED DESCRIPTION OF THE INVENTION
[0071] In the following detailed description, numerous specific details are set forth in order to provide a thorough understanding of the invention. However, it will be understood by those skilled in the art that the present invention may be practiced without these specific details. In some instances, well-known methods, procedures, components and circuits have not been described in detail, for the sake of brevity.
[0072] FIG. 1 illustrates an anterior implant according to one embodiment of the present invention.
[0073] Anterior implant 1 includes four straps 10 , each ending with a looped end 20 . Anterior implant 1 may also include a loop 8 between two interior straps 10 .
[0074] Anterior implant 1 may include spaces 4 for reducing the weight thereof.
[0075] FIG. 2 illustrates an anterior view of the pelvic area before installing the anterior implant.
[0076] The anterior view of pelvic area 34 refers to the side allowing surgical access through the patient's vaginal opening.
[0077] Denoted bones are the ischial spine 27 extending from the posterior border of the ischium 26 , and the sacrum 46 .
[0078] Also shown are the perineal body 52 , and the cervix 50 extending from the uterus (womb) 48 .
[0079] Pelvic area 34 includes two ligaments of arcus tendineous fascia pelvic (ATFP) 30 and two ligaments of sacrospinous (SS) 28 .
[0080] FIG. 3 illustrates the view of FIG. 2 after installing the anterior implant.
[0081] Anterior implant 1 is used for reconstructing the anterior pelvic floor, including prolapse of the urinary bladder and/or the colon and the small intestine.
[0082] Two straps 10 of anterior implant 1 are threaded into two ATFP ligaments 30 , and the other two straps 10 are inserted into two SS ligaments 28 .
[0083] Loop 8 may be sutured to cervix 50 for improving strength and security of the anchoring of anterior implant 1 .
[0084] FIG. 4 illustrates a posterior implant according to one embodiment of the present invention.
[0085] Posterior implant 2 includes two straps 10 , each ending with a looped end 20 . Posterior implant 2 may include a loop 36 between two interior straps 10 , and another loop 9 at the opposing side.
[0086] Posterior implant 2 may include spaces 4 for reducing the weight thereof.
[0087] FIG. 5 illustrates the view of FIG. 2 after installing the posterior implant.
[0088] Posterior implant 2 is used for reconstructing the posterior pelvic floor, including prolapse of the colon, the small intestine and/or the uterus (womb).
[0089] Two straps 10 of posterior implant 2 are inserted into two SS ligaments 28 .
[0090] Loop 36 may be sutured to cervix 50 , and loop 9 may be sutured to perineal body 52 for improving the strength and security of the connection.
[0091] FIG. 6 illustrates the head of a needle for threading the straps of the implants, according to one embodiment of the present invention.
[0092] A needle 6 is used for threading each of straps 10 through ATFP ligaments 30 and SS ligaments 28 .
[0093] The head of needle 6 includes a rod 18 , which may be manually slid back and forth in a track 16 within a body 14 , as in brake cables.
[0094] The edge 42 of rod 18 may be inserted into a niche 40 . The tip 12 of needle 6 is located at the edge of body 14 .
[0095] FIG. 7 illustrates the first step of threading the straps of the implants, using the needle of FIG. 6 .
[0096] The surgeon inserts looped end 20 of strap 10 into niche 40 , and traps it by rod edge 42 of rod 18 into looped end 20 .
[0097] In case that the surgeon has not succeeded in inserting rod 18 into looped end 20 , the surgeon may trap looped end 20 by applying physical force of rod edge 42 towards the limiting wall thereof in niche 40 .
[0098] According to another embodiment the surgeon may trap strap 10 directly by applying physical force of rod edge 42 on the end of strap 10 towards the limiting wall thereof in niche 40 .
[0099] FIG. 8 illustrates the second step of threading the straps of the implants, using the needle of FIG. 6 .
[0100] The surgeon then pushes tip 12 together with body 14 into an ATFP ligament 30 or into an SS ligament 28 , threading looped end 20 and strap 10 through the ligament.
[0101] FIG. 9 illustrates the third step of threading the straps of the implants, using the needle of FIG. 6 .
[0102] The surgeon then slides rod edge 42 out of niche 40 , releasing looped end 20 from rod edge 42 .
[0103] FIG. 10 illustrates the fourth step of threading the straps of the implants, using the needle of FIG. 6 .
[0104] The surgeon then pulls body 14 together with tip 12 out of ATFP ligament 30 or SS ligament 28 . Since looped end 20 has been released at the third step, and since ligament 30 (or 28 ) shrinks tightly, as shown by the arrows, strap 10 remains threaded while tip 12 exits.
[0105] FIG. 11 illustrates the needle of FIG. 6 and its operation.
[0106] The surgeon holds handle 24 of needle 6 , and slides rod 18 by toggling a toggle arm 22 , which is connected to rod 18 .
[0107] Needle 6 as a whole may be flexible like a brake cable, thin and long enough to occupy minimal surgery space.
[0108] Since tip 12 is inserted into the pelvic area, and toggle arm 22 is far away tip 12 , toggle arm is located outside the body of the patient and may be located farther and outside the surgical area.
[0109] It may be appreciated according to these steps that the surgeon can thread strap 10 from the side having surgical access, without requiring any additional perforations of the body from the opposing direction.
[0110] FIG. 12 illustrates the operation of the needle of FIG. 6 in aspect of the surgeon's access to the pelvic area.
[0111] The surgeon inserts finger 32 thereof into the vagina 44 between the patient's legs 38 and reaches pelvic area 34 (the lines of the parts inside are dashed). The surgeon then separates an SS ligament 28 from the other organs, locates tip 12 of needle 6 on a selected threading point on SS ligament 28 , and traps trapping looped end 20 to niche 40 of needle 6 .
[0112] The surgeon then penetrates tip 12 through SS ligament 28 and pushes into the desired depth; then releases looped end 20 from needle 6 by toggling toggle arm 22 , using the other hand thereof.
[0113] The surgeon can then pull tip 12 back, leaving looped end 20 and strap 10 at the side beyond, having tight shrinking of SS ligament 28 towards strap 10 at the threaded point.
[0114] Tying of strap 10 is not required due to natural tying of SS ligament 28 to strap 10 .
[0115] FIG. 13 illustrates the operation of the needle of FIG. 6 in aspect FIG. 12 , to another ligament.
[0116] The surgeon inserts the finger 32 thereof into vagina 44 , then separates an ATFP ligament 30 , and locates tip 12 of needle 6 on the selected threading point, after trapping looped end 20 to niche 40 of needle 6 .
[0117] The surgeon then penetrates tip 12 through ATFP ligament 30 and on to the desired depth; then releases looped end 20 from needle 6 by toggling toggle arm 22 , using the other hand thereof, then pulls tip 12 back leaving looped end 20 and strap 10 at the side beyond, having tight shrinking of ATFP ligament 30 towards strap 10 at the threaded point.
[0118] In the figures and description herein, the following numerals and symbols have been mentioned:
[0119] numeral 1 denotes an anterior implant;
[0120] numeral 2 denotes a posterior implant;
[0121] numeral 4 denotes a space for reducing the weight of an implant;
[0122] numeral 6 denotes a needle according to one embodiment of the present invention;
[0123] numeral 8 denotes a loop in the anterior implant for anchoring it to the cervix;
[0124] numeral 9 denotes a loop in the posterior implant for anchoring it to the perineal body;
[0125] numeral 10 denotes a strap extending from the implant;
[0126] numeral 12 denotes a tip of the inventive needle;
[0127] numeral 14 denotes the body of the inventive needle;
[0128] numeral 16 denotes a track within the body of the needle;
[0129] numeral 18 denotes a rod traveling within the body of the needle;
[0130] numeral 20 denotes a looped end at the edge of the implant strap;
[0131] numeral 22 denotes a toggle arm for trapping and releasing the looped end;
[0132] numeral 24 denotes a handle of the needle;
[0133] numeral 26 denotes the ischium (bone);
[0134] numeral 27 denotes the ischial spine (bone);
[0135] numeral 28 denotes a sacrospinous (SS) ligament;
[0136] numeral 30 denotes an arcus tendineous fascia pelvic (ATFP) ligament;
[0137] numeral 32 denotes a surgeon's finger;
[0138] numeral 34 denotes the pelvic area;
[0139] numeral 36 denotes a loop in the posterior implant for anchoring it to the cervix;
[0140] numeral 38 denotes a patient's leg;
[0141] numeral 40 denotes a niche in the needle for trapping the looped end of the strap;
[0142] numeral 42 denotes the edge of the rod sliding in the track;
[0143] numeral 44 denotes the vagina, into which the surgeon inserts the finger thereof;
[0144] numeral 46 denotes the sacrum (bone);
[0145] numeral 48 denotes the uterus (womb);
[0146] numeral 50 denotes the cervix, extending from the uterus; and
[0147] numeral 52 denotes the perineal body;
[0148] While certain features of the invention have been illustrated and described herein, the invention can be embodied in other forms, ways, modifications, substitutions, canchores, equivalents, and so forth. The foregoing description of the embodiments of the invention has been presented for the purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Many modifications and variations are possible in light of this disclosure. It is intended that the scope of the invention be limited not by this detailed description, but rather by the claims appended hereto.
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In one aspect, the present invention may be directed to a needle for surgical threading of a strap of an implant through a tissue, the needle comprising: a trap for trapping the strap to the needle while the needle may be at the accessible side of the tissue; a tip for threading the trapped strap from the accessible side to the opposing side; and a mechanism for releasing the trap, the mechanism driven from the accessible side of the tissue, thereby allowing return of the tip to the accessible side of the tissue while abandoning the strap at the threaded point, thus performing the threading from the accessible side of the tissue.
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TECHNICAL FIELD
This invention relates in general to electronic card extractors.
More particularly, this invention relates to electronic card extractors for avionic equipment items of an aircraft.
BACKGROUND
The avionic equipment items of an aircraft are made up of computers having the form of electronic cards installed in units or cabinets, connected to the electrical bundle of the aircraft. In practice, the electronic cards are installed by one of their edges into a slot provided for this purpose on a base installed in a unit. The back of the unit has a plurality of connectors disposed perpendicular to the base, so as to connect electrically the electronic cards installed on the base by an edge perpendicular to and immediately adjoining the edge installed in the slot of the base.
Usually, in a standard device comprising electronic cards, in order to remove an electronic card it is necessary to make sure to have cut off the electrical supply of the electronic card in order to avoid any damage to the electronic components before actuating the extractor in order to extract the card.
In avionic equipment items, there are modular equipment items wherein one of the sought objectives is to retain the availability of various avionic functions even when a given electronic card is removed. In concrete terms, it is a matter of being able to remove cards independently of one another and to see to it that the equipment is able to provide a given function despite the absence of one or more electronic cards.
In practice, in order to extract an electronic card, the operator sends out an extraction request on a central computer for a given card. The other cards then are reconfigured in order to be able to function without the chosen card and the power supply of the latter is cut off. A visual indicator tells the operator that he may extract the card.
Nonetheless, the risk remains that the operator will not remove the card on which the extraction request has been implemented, but another card. An erroneous extraction may damage the card in question. In addition, malfunctions of the system may occur since the system has not been reconfigured to operate without the card extracted by error.
The problem thus is to make extraction of the card subject to the modular preparation of the other electronic cards and to the cutoff of current thereto.
More generally, the problem therefore is to prevent incorrect or erroneous extractions of the electronic cards.
In order to be extracted, the cards are provided with extractors in the form of a lever making it possible to reduce an extraction force applied on the lever in order to contribute toward extracting the card.
In fact, the evolution of the number of components on the electronic cards led to the increase of the number of contacts between the cards and their connectors. The contact pressure on each of the cards is such that it is necessary to provide an extractor. In practice, an extraction may require a force ranging up to 350 N. It is understood that without the aid of an extractor, it is impossible to extract the card.
SUMMARY
Based on these observations, the invention proposes a base for an electronic card comprising at least one slot adapted for accommodating an electronic card with an extraction lever installed rotatably in relation thereto and adapted for pivoting between a first position and a second position, the lever having a support end adapted for coming to rest on a support element of the base in order to extract the electronic card from the base when the lever changes over from the first to the second position, the support element having a first state in which the extraction lever does not bear on the support element when changing over from the first position to the second position, and a second state, in which the lever bears on the element when changing over from the first to the second position, the rotation of the lever from the first position to the second position then bringing about a movement for extraction of the card through resting of the support end of the lever on the support element along a support direction.
The invention thus proposes to make the support surface for the extraction lever inoperative, so as to make the latter inoperative through lack of support surface when that is necessary. In other words, since the efficacy of the lever is dependent on the presence of a support surface, the fact of making the latter inoperative prevents activation of the lever and therefore stands in the way of any erroneous extraction of the card.
This ensures a greater reliability during maintenance operations.
According to one possible advantageous characteristic of the invention, the support element is installed free in translation along the support direction, and the changeover from the first to the second state is accomplished by a mechanical blockage of the support element in translation in a position in which the support end of the lever bears on the said element during rotation of the lever from the first position to the second position, then bringing about a movement for extraction of the card.
In this way, the number of mechanical parts in motion advantageously is limited.
According to possible advantageous characteristics of the invention, combined if need be:
the support element is movable between a first position in which it is not in the path of the support end of the lever when the latter changes over from its first to its second position, and a second position in which the support element is in the said path of the support end of the lever, the changeover from the first to the second state being accomplished by a movement and a mechanical blockage of the support element from the said first position to the said second position; the support element is movable in translation along the support direction; the support element is movable along a direction more or less perpendicular to the support direction; the mechanical blockage is accomplished with the aid of an electromagnet.
According to another aspect, the invention relates to an extraction device comprising at least one electronic card having a lever having a support end adapted for coming to rest on a support element and a base such as described above.
According to an advantageous aspect, the extraction device comprises visual means indicating that the support element is in the second state.
According to another aspect, the invention relates to an electronic card extraction device comprising a plurality of interconnected cards and control means adapted for:
receiving an extraction request for a given card, reconfiguring the other cards so as to provide the function or functions of the card to be extracted, sending a signal to the support element of the selected card to change over from the first to the second state, indicating by a visual indicator that the card is ready to be extracted.
According to another aspect, the invention relates to a method for extraction of an electronic card with the aid of an extraction device such as described above, comprising the following steps:
sending out an extraction request for a given card, identifying with the aid of the visual indicator that the card is ready to be extracted, extracting the card by causing the lever to change over from the first to the second position.
According to another aspect, the invention relates to an aircraft equipped with a base and/or an extraction device and/or a control device such as described above.
BRIEF DESCRIPTION OF THE DRAWINGS
The explanation of the invention now will be continued with the detailed description of two exemplary embodiments, given below by way of illustration and non-limitative, with reference to the attached drawings. Thereon:
FIGS. 1 a to 1 c show the operating principle of an extraction lever for an electronic card in general;
FIGS. 2 a to 2 c show the operating principle of an extraction lever for an electronic card according to the invention;
FIG. 3 is a side view of an alternative embodiment of an extraction device for an electronic card according to the invention;
FIG. 4 is a side view of another embodiment of an extraction device for an electronic card according to the invention.
FIG. 5 is a schematic view of a control device connected to a plurality of bases and cards.
DETAILED DESCRIPTION
Generally speaking, the same numerical references are used in the description of the attached Figures for identical or similar elements.
FIGS. 1 a , 1 b and 1 c schematically show in a side view an electronic card 1 installed by its lower edge in a slot 2 provided for this purpose in a base 3 installed in a unit 4 . The back of unit 4 has a connector 5 disposed perpendicular to the base in the same plane as slot 2 so as to connect electrically the electrical contacts of the electronic cards disposed on an edge perpendicular to and immediately adjoining the edge installed in the slot of the base.
On FIGS. 1 a to 1 c the electrical contacts of card 1 have been shown, the other cards, not visible, being installed in the same way.
Card 1 has, at the end opposite electrical contacts 6 , a lever 10 installed rotatably on card 1 through a pivot 11 perpendicular to the card and to the longitudinal direction of the latter.
As visible more particularly on FIGS. 1 b and 1 c , when the lever is pivoted around pivot 11 from a first position ( FIG. 1 a ) to a second position ( FIG. 1 c ), a support end 12 of the lever bears on an exterior face of base 3 forming a support surface, reducing the force applied to the opposite end of the lever in order to convert it into a force for extraction of the card from its connector 5 .
The contact forces between contacts 6 and connector 5 are such that the use of an extraction lever 10 is necessary in order to extract card 1 from connector 5 . The invention benefits from this finding by proposing to provide or not provide a support surface for the lever, in this way allowing or precluding extraction of the card.
A first embodiment of an extraction device according to the invention is visible on FIGS. 2 a to 2 c . According to the same mechanical principle as on FIGS. 1 a to 1 c , the extraction device comprises an extraction lever 10 for electronic card 1 installed along pivot 11 in relation to the card, so that it may pivot between a first position and a second position. The movement for extraction of the card is dependent on the presence of a support surface for the support end 12 of the lever.
As visible on FIGS. 2 a to 2 c , the base according to the invention has a support device 20 . The latter comprises a support plate 21 integral with a rod 22 at least partially ferromagnetic and installed translatably in base 3 between a first retracted position such as visible on FIG. 2 a and a second position referred to as support such as visible on FIGS. 2 b and 2 c . Translation from the first position to the support position is controlled by an electromagnet 23 composed of the ferromagnetic part of rod 22 on which there is installed an electrical coil 24 supplied by an electrical circuit 25 subjected to a DC voltage. Circuit 25 may be interrupted with the aid of a switch 26 . The ferromagnetic part of rod 22 and coil 24 jointly form an electromagnet.
When switch 26 is closed, coil 24 generates an electromagnetic field acting on the ferromagnetic part of rod 22 , thus causing it to change over from the retracted position visible on FIG. 1 to the support position visible on FIG. 2 b in which support plate 21 is moved forward so that support end 12 of lever 10 bears on the support plate. Lever 10 then brings about a movement for extraction of the card during its rotation around pivot 11 as visible on FIG. 2 c.
In this way, advantageously, since the extraction of the card is dependent on the presence of the support surface for lever 10 , any untimely extraction is prevented as long as support element 21 is not in the second position referred to as support.
An alternative embodiment is shown on FIG. 3 .
According to the same principle as set forth on FIGS. 2 a and 2 c , in this embodiment a support device 30 is installed in base 3 . This device comprises a support plate 31 integral with a rod 32 installed translatably in base 3 and integral with its end opposite a stop plate 33 . A spring 34 comes to rest on the free face of plate 33 so as to come to flatten the latter against two stops 35 projecting from base 3 .
According to the same principle as set forth for FIGS. 2 a to 2 c , rod 32 has a ferromagnetic portion around which there is installed an electrical coil 36 connected to an electrical circuit 37 subjected to a DC voltage. The electrical circuit 37 may be interrupted with the aid of a switch 38 . The ferromagnetic part of rod 32 and coil 36 jointly form an electromagnet.
In operation, device 30 has a rest position such as visible on FIG. 3 , in which spring 34 comes to flatten stop plate 33 against stops 35 , support plate 31 then being in a position referred to as support for end 12 of lever 10 . If the latter came to be lowered while switch 38 is open, support plate 31 would retract into device 30 by compressing spring 34 . The extraction lever then would not bear on support plate 31 and there would be no effect of movement for extraction of the card for lack of support surface.
When switch 38 is closed, coil 36 generates an electromagnetic field around the ferromagnetic part of shaft 32 , thus blocking the assembly in translation, which immobilizes support plate 31 . Lever 10 then may be lowered until its support end 12 comes to rest on support plate 31 from now on immobilized, and it then brings about a movement for extraction of the card through support on this plate in a manner similar to the extraction illustrated on FIGS. 2 b and 2 c.
Spring 34 and coil 36 forming an electromagnet with shaft 32 are sized so that a minimal voltage is required to block translation of the assembly when switch 38 is closed.
Another embodiment is shown schematically on FIG. 4 . In this embodiment, an electronic card 1 similar in every respect to the electronic cards such as described above and having a lever 10 with a support end 12 is adapted for cooperating with a locking mechanism 40 . The latter has a lock 41 fastened to a base, not shown, and in which a slot is provided to accommodate electronic card 1 in a manner analogous to the embodiments described above. It is a matter of an electromagnetic lock connected to an electrical circuit, not shown, and similar in every respect to the electrical circuit described above. Electromagnetic lock 41 has a feeler gauge 42 controlled in translation by an electromagnet shown disposed inside the lock. The locking mechanism 40 is fastened onto the base (not shown) at the level of support end 12 of the lever, when card 1 is inserted therein. The feeler gauge 42 is adapted for moving in translation between a first position in which it is retracted completely into the body of lock 41 and a second position, such as shown on FIG. 4 , in which the feeler gauge is in the path of support end 12 when the lever pivots around pivot 11 . Feeler gauge 42 then serves as support element for support end 12 of the lever, then bringing about a movement for extraction of the card in a manner analogous to the extraction shown on FIGS. 2 b and 2 c . In an embodiment not shown, the lock is fastened in a machining provided for this purpose on the base.
According to an advantageous aspect of the invention able to be applied to all the embodiments described above, in a device comprising a plurality of interconnected electronic cards (not shown), visual indication means are provided on the card or close thereto in order to indicate to the operator that the support means are activated. It is a matter, for example, of a light-emitting diode connected to the power supply circuit of the electromagnet and which indicates whether the latter is carrying current.
According to the embodiments, the operator knows, depending on whether the diode is on or off, whether the card is ready to be extracted.
In practice, the switches of the power supply circuits of the embodiments of the invention described above are controlled by a control device 50 for the extraction of electronic cards. In a device comprising a plurality of interconnected electronic cards 52 , this control device 50 is adapted for receiving from the operator an extraction request for a given electronic card, and for then reconfiguring the other cards so that the latter provide the function or functions of the card to be extracted. The device then sends a signal to the corresponding switch of the card to activate the support means and cause them to change over to a state in which the lever bears on the support element. At the same time, if a visual indicator 51 is present, the latter is swung to a state in which it indicates to the operator that the chosen card is ready to be extracted.
In practice, the operator sends out an extraction request for a given card on the control device 50 . He then identifies, with the aid of the visual indicator 51 , that the card in question is ready to be extracted and, the support means being activated, he acts on the lever so as to cause it to change over from the first to the second position such as described above in order to extract the card in question.
Numerous other variants are possible according to circumstances, and in this regard it is recalled that the invention is not limited to the examples described and shown.
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A base for an electronic card includes at least one slot adapted for accommodating an electronic card with an extraction lever installed rotatably in relation thereto and adapted for pivoting between a first position and a second position. The lever has a support end adapted for coming to rest on a support element of the base in order to extract the electronic card from the base when the lever changes from the first to the second position. The support element has a first state in which the extraction lever does not bear on the support element when changing from the first position to the second position, and a second state, in which the lever bears on the support element when changing from the first to the second position. This creates a movement for extraction of the card through the support end along a support direction.
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BACKGROUND OF THE INVENTION
This invention is directed to a carriage reciprocator and positioner. This invention is related to a class of devices known as chain reciprocators.
Present day chain reciprocators have carriages connected directly to a chain. Reciprocation of the carriage is achieved by reversing the motion of the chain. Reversal of chain motion can have detrimental effects especially in those applications where high speed, short stroke carriage reciprocation is required. In such applications and others the chain life is shortened since the chain is required to take most of the inertial shock of carriage reversal. In addition, in high speed, short stroke reciprocation environments, one section of the chain tends to wear excessively which usually leads to differential wear of the sprocket teeth and resultant chain slap.
SUMMARY OF THE INVENTION
Accordingly, it is an object of this invention to provide a carriage reciprocator and positioner having a chain which continuously runs in one direction and wherein most of the inertial shock of carriage reversal is absorbed by the carriage. It is a further object of this invention to provide a device wherein all of the chain is used, wherein device longevity and reliability are increased, wherein the velocity of the carriage is controllable, wherein chain life is extended and wherein a unique arrangement of air clutches, chain sprockets and associated elements, are arranged to automatically achieve carriage reciprocation along an adjustable stroke length. These and other objects of the invention are achieved as follows.
A carriage is provided with two air clutches each of which controls a respective one of two carriage mounted chain sprockets. The carriage is arranged to move along two vertically spaced co-planar rails which are each separately attached to a housing. The housing supports a variable speed motor which is arranged to continuously drive an elongated roller chain around two spaced co-planar sprockets. The chain lies in a plane which is parallel to and situated between the carriage plane and the plane of the rails.
The continuously running roller chain presents one direction of chain motion to the top of the carriage and an opposite direction of chain motion to the bottom of the carriage. One of the carriage mounted sprockets engages the chain near the top of the carriage and the other carriage mounted sprocket engages the chain near the bottom of the carriage. Each of the carriage mounted sprockets is arranged to normally idle with chain motion and the carriage is then normally stationary. However, actuation of an air clutch prevents its associated sprocket from spinning with chain motion and effectively locks that sprocket and clutch to the chain. Since the clutch is secured to the carriage, the carriage will be carried along the rails by the chain in a linear direction which is dependent upon which portion of the chain was so engaged. The carriage will move in one direction until the then operative clutch is de-actuated and the other clutch is actuated whereupon the carriage reverses direction.
Automatic actuation and de-actuation of the two air clutches is achieved with the use of a four way, two position, pilot operated spool valve which is mounted on the carriage and which is provided with a suitable source of compressed air. Two control shafts extend from either side of the spool valve. Each of the control shafts is arranged to eventually contact a respective one of two shock absorbers which are each adjustably secured to the housing. The spool valve is arranged to actuate one clutch while simultaneously deactivating the other. When air is supplied to the spool valve it will assume one of two positions and actuate one of the two clutches. The carriage will move in a particular direction until one of the spool valve control shafts contacts one of the two shock absorbers. At the moment of contact the spool valve assumes its other position deactuating the then inoperative air clutch. In this manner carriage direction is automatically reversed and the carriage is caused to reciprocate between the two shock absorbers.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric view of a carriage reciprocator and positioner according to this invention; for clarity of presentation a housing to which some of the elements are attached is not shown and certain dimensions have been exaggerated.
FIG. 2 is a partial cross-sectional view, taken along the lines 2--2, of the device shown in FIG. 1; this view highlights the configuration of an air clutch and associated carriage chain sprocket both of which are part of the device shown in FIG. 1.
FIG. 3 is a plan view, partially sectioned of the air clutch shown in FIG. 2 and is taken along the line 3--3 in FIG. 2.
FIG. 4 is a plan view, partially sectioned, of the carriage chain sprocket shown in FIG. 2 and is taken along the line 4--4 in FIG. 2.
FIG. 5 is a schematic diagram of the air clutches and a controlling spool valve, all of which are part of the device shown in FIGS. 1 and 2.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, the carriage reciprocator and positioner includes a conventional variable speed motor 12 which is conventionally arranged to turn a driven sprocket 14. An idler sprocket 16, spaced apart from, but in the same plane as, the driven sprocket 14, is also provided. A continuous roller chain 22 extends around and between the driven sprocket 14 and the idler sprocket 16. An upper rail 18 and a lower rail 20 are also provided. The rails 18, 20 have hexagonal cross sections. The rails 18, 20 lie in a plane parallel to but behind the plane in which the sprockets 14, 16 and chain lie.
For clarity of presentation, the housing which supports the motor 12, idler sprocket 16 and rails 18, 20 is not shown in FIG. 1. However, it is to be understood that these elements are conventionally secured to such unshown housing.
A carriage 24 rides on and between the upper and lower rails 18, 20. Four parallel and spaced axles 26 project rearwardly from the carriage 24. The axles 26 are secured to the carriage 24 by any conventional means such as bolts 30. Each axle 26 is provided with a rotatable wheel 28. Two of the wheels 28 are arranged to move along the upper rail 18 and the other two wheels 28 are arranged to move along the lower rail 20. The carriage 24 is provided with at least one support pin 25 which may be secured to the carriage in any suitable fashion and upon which any suitable element, such as a spray gun, may be supported.
Upon the carriage 24 are mounted a four way spool valve 32, two identical air clutches 34, 35 and two identical carriage chain sprockets 36 (one of which does not appear in FIG. 1). The spool valve 32 is secured to the carriage 24 with a standoff support 33.
With further reference to FIG. 1, the spool valve 32 is provided with an air inlet 32a and air outlet 32a'. Compressed air is fed to the inlet 32a from a controllable source (not shown) through a hose (not shown) of appropriate length. Each of two air control lines 32b, 32c extends from the spool valve 32 to a respective one of the two air clutches 34, 35. Each of two spool valve control shafts 32d, 32e extend from a respective side of the spool valve 32 in a plane parallel to the plane in which the chain 22 lies.
Each of two shock absorbers 38, 39 is adjustably set opposite a respective one of the two spool valve control shafts 32d, 32e. Each of the two shock absorbers 38, 39 is movably mounted on a housing (not shown) with a respective one of two support bars 38a, 39a. The distance between the shock absorbers 38, 39 is defined as the stroke of the carriage 24. The stroke may be made smaller or larger by adjusting the distance between the shock absorbers 38, 39. (As will be made clearer below, when one of the two air clutches 34, 35 is actuated, the carriage 24 will move in one direction until one of the two spool valve control shafts 32d, 32e contacts a respective one of the two shock absorbers 38, 39. At the moment of contact the spool valve 32 automatically deactivates the operative one of the two air clutches 34, 35 and actuates its counterpart. This action causes the carriage 24 to move in an opposite direction until the other one of the two spool valve control shafts 32d, 32e contacts the other one of the two shock absorbers 38, 39. In this manner, the carriage 24 is caused to reciprocate between the two shock absorbers 38, 39).
Referring to FIG. 2, which is a cross section, along the line 2--2, of the device shown in FIG. 1, a detailed view of one of the two identical air clutches 34, 35 and of one of the two identical carriage chain sprockets 36, 37 is shown.
The air clutch 34 includes three major elements: a clutch cylinder 340, which is stationary with respect to the carriage 24, a clutch piston 341 which is axially movable with respect to the clutch cylinder 340, and a friction liner 342 which is secured to the flat head 341a of the clutch piston 341.
The clutch cylinder 340 is substantially circular in shape and is rigidly secured to the carriage 24 by any suitable means (not shown). The clutch cylinder 340 is provided with an air inlet 340a which accommodates the air control line 32b. The clutch cylinder 340 is also provided with a centrally located, elongated, cylindrically shaped hub 340b which is flanked by two cylindrically shaped bosses 340d, 340e. The clutch piston 341 is also substantially circular in shape. One side, defined as the piston head 341a, faces a land 36a on the carriage chain sprocket 36; the other side is provided with two circular recesses 341b, 341c which flank a circular hole 341d which is concentric with the hub 340b of the clutch cylinder 340. Each of the two bosses 340d, 340e on the cylinder 340 normally repose within a respective one of the two recesses 341b, 341c in the piston 341. This arrangement prevents the piston 341 from rotating with respect to the cylinder 340 but allows the piston 341 to slide along the hub 340b of the cylinder 340.
The clutch piston also includes a disc shaped friction liner 342 which is secured to the piston head 341a by conventional means (not shown). Two cup shaped "O"-rings 343, 344 prevent air leakage as the piston 341 moves along the hub 340b.
With further reference to FIG. 2, a detailed view of one of the carriage chain sprockets 36, 37 is also shown. The sprocket 36 is conventional in design and is arranged to normally rotate on a reduced diameter portion of the hub 340b. Two captured roller bearings 36b, 36c are provided. A threaded bolt 40, which extends from the valve support 33 and through the bore 340c in the hub 340b is provided with a washer 40a and a nut 40b. (See FIG. 4). The two bearings 36b, 36c repose between the washer 40a and the shoulder 340f of the reduced diameter portion of the hub 340b. This arrangement insures not only that the sprocket 36 freely rotates but also that a preferred distance is maintained between the land 36a of the sprocket 36 and the friction liner 342 when no compressed air is introduced into the inlet 340a.
FIG. 2 also shows part of the housing 11 in which all of the foregoing elements are lodged. The shock absorber support bar 39a is shown extending to a housing overhang 11a which extends the length of the housing and upon and along which the support bar 39a and its companion support bar 38a slide. Each of the two shock absorber support bars 38a, 39a may be removably secured to a selected portion of the overhang 11a by means of a clamp 11b and bolts 11c or in any other suitable manner.
With further reference to FIG. 2, the carriage 24 is also provided with four identical spacers 42 which project from the carriage 24 toward the chain 22. The top two of the spacers 42 support an upper chain guide rail 44 and the bottom two of the spacers 42 support a lower chain guide rail 45. Both chain guide rails 44, 45 extend the length of the carriage and insure proper registration of the chain 22 with each of the two carriage chain sprockets 36, 37.
In FIG. 5, a pneumatic diagram of the spool valve 32 and the clutches 34, 35 is presented. With the spool valve in the first position shown in FIG. 5, the lower clutch 34 is connected to a source, S, of compressed air and the upper clutch 35 is connected to the air return R. Hence the lower clutch 34 is actuated and the upper clutch 35 is deactuated.
The spool valve 32 is a four way, pilot operated, two position device of conventional design. As is well known the spool valve 32 operates on a pressure differential principal. Actuation of, for example, the control shaft 32d exhausts its associated pilot operator to atmosphere to thereby create a pressure differential within a poppet chamber (not shown) which causes the poppets (not shown) to shift. The spool valve 32 then assumes its second position and the poppets are locked until the other control shaft 32e is actuated. When the spool valve 32 assumes the second position, the upper clutch 35 is connected to the source, S, and the lower clutch 34 is connected to the return, R.
OPERATION
When the variable speed motor 12 is energized, the chain runs continuously in a clockwise direction at the speed set by the motor speed controllers (not shown). The carriage 24 is initially stationary. When compressed air, at 75 psi for example, is introduced into the inlet 32a of the spool valve 32, one of the two air clutches 34, 35 is actuated depending upon the initial condition of the spool valve 32. If the lower air clutch 34 is actuated, its piston 341 will slide along its hub 340b until the friction liner 342 engages the land 36a on the carriage chain sprocket 36. Before the liner 342 makes contact, the sprocket 36 idly spins with the motion of the chain 22. However, once the liner 342 fully abuts the sprocket land 36a, the sprocket 36 is no longer free to turn. Hence the sprocket 36, chain 22, and clutch 34 are effectively locked together. Since the clutch 34 is secured to the carriage 24, the carriage will move linearly in chain direction "A". (See FIG. 1) The carriage will move in direction "A" until the spool valve control shaft 32d encounters the left shock absorber 38 at which time the lower clutch 34 is deactuated and the upper clutch 35 is actuated. When pressurized air is supplied to the upper clutch 34, it locks or brakes its associated carriage sprocket 37 in the same manner and the carriage 24 then travels linearly in direction "B" until the right spool valve control shaft 32e encounters the right shock absorber 39. When contact is made, the direction on the carriage 24 is reversed and so on. In this manner the carriage 24 is caused to reciprocate until pressurized air is no longer supplied to the spool valve 32.
It is clear that both air clutches 34, 35 act as a brake. A unique design feature of the air clutch 34 is the absence of any biasing element which would act to return the clutch piston 341 to the unengaged position (shown in FIG. 2) when pressurized air is no longer supplied to the clutch 34. Through experimentation it was discovered that when pressurized air is removed from the clutch 34, the rotational movement of the freed sprocket 36, among other supposed things, creates enough force against the liner 342 and piston 341 to push these united elements away from the land 36a on the sprocket 36 so that they assume the unengaged position portrayed in FIG. 2.
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An air brake includes a friction liner attached to a piston-like member which is arranged to reciprocate with respect to a stationary member. The piston-like member is urged into its inoperative position without the use of a biasing element such as a spring or spring-like member. sp
This is a division of application Ser. No. 888,190 filed Mar. 20, 1978, now U.S. Pat. No. 4,227,421.
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The invention relates to an apparatus for detecting yarn movement.
DESCRIPTION OF THE PRIOR ART
According to the prior art, there is known an apparatus for detecting yarn movement comprising a yarn guide unit through which a yarn can be passed, the yarn guide unit having a support surface adapted to be frictionally engaged by the yarn, a converter element associated with the support surface for generating an electrical output signal indicative of a longitudinal yarn movement and a member for biasing the yarn into engagement with the support surface for mechanically amplifying the signal, the member being movably mounted relative to the support surface in the yarn guide unit.
In an apparatus of the type defined as known from Swiss Patent 546,840, a member acting on the yarn is a contact member maintained in point contact with the yarn for biasing it into engagement with a support surface of a friction body by acting directly on the yarn at its contact point with the support surface to thereby amplify the useful signals by increasing the contact pressure of the yarn by mechanical means. The contact member is spring-loaded.
In a yarn monitoring apparatus known from FR-A-1,498,049, the presence and/or movement of the unbroken yarn is detected by guiding it under tension over a support surface belonging to a cantilevered resilient tongue member the other end of which transmits any vibrations directly to the converter element. A large proportion of the energy transmitted by the yarn to the support surface is dissipated by the deformation of the tongue member and its movement about its mounting location. As a result, the useful signal is only of a limited strength.
In an apparatus known from Swiss Patent 479 478 (corresponding to U.S. Pat. No. 3,676,769), a member is a pressure-exerting member biasing the yarn into engagement with a support surface with a sufficient contact pressure. The pressure-exerting member serves the purpose of creating an additional electrostatic charge by frictional engagement with the yarn, resulting in strong potential variations which are readily detectable for thus detecting the movement of the yarn.
In an apparatus known from EP-A 0,139,231 (corresponding to U.S. Pat. No. 4,605,875), the yarn is deflected through a guide ring connected to a foot portion. Provided on the foot portion is a piezo-electric converter element for converting vibrations of the guide ring into electric signals. The longitudinal movement of the yarn results in such vibrations of the guide ring due to its frictional contact therewith. As long as the yarn is not moved, however, this arrangement results in a relatively strong noise signal, so that the output signal of the converter element is difficult to detect or even unfit for use due to the unfavourable signal-to-noise ratio. A movement of a smooth yarn at a slow rate of advance is scarcely detectable.
An apparatus known from DE-B-1,018,644 serves for detecting a yarn or web breakage. In this apparatus, a ball member biased towards a switch contact is prevented from making contact by the yarn or web as long as it is not broken. A movement of the yarn or web is not indicated.
Known from GB-A-2,059,594 is an apparatus for indicating the presence and movement of a yarn by the employ of a piezo-electric converter element directly engaged by the yarn. The converter element is shaped as a cantilevered rod fixedly mounted at one end and contacted by the yarn at its opposite free end. A pre-biased resilient stop member acts on the converter element at a location between its fixed and free ends in a direction substantially parallel to the direction of movement of the yarn. The converter element monitors the yarn directly.
It is an object of the present invention to improve an apparatus of the type described above so as to result in an improved signal-to-noise ratio of the output signal while being of simple construction.
SUMMARY OF THE INVENTION
This object is attained, according to the invention, providing an apparatus for detecting yarn movement comprising a yarn guide unit for slidably guiding a moving yarn, and a converter cooperating with the yarn guide unit for generating an electric signal. With the aim of improving the signal-noise ratio of an apparatus of this type, there is provided a member mounted for movement relative to the yarn guide unit and disposed such that the yarn is guided between the member and the yarn guide unit in simultaneous contact with the member and the yarn guide unit, the member being subjected to a biasing action relative to the yarn guide unit. The converter cooperates with the member for generating the output signal in response to movements of the member and the support surface relative to one another and for monitoring the movements of the member and/or its impacts on said support surface.
In this embodiment, it is not the yarn itself which is primarily used for generating the useful signal, but rather the member moved by the yarn during its longitudinal movement, the movements of this member being readily detectable. Since the detected signal resulting from the movement of the member are substantially stronger than the noise signal in the stationary state of the yarn and the member, the signal-to-noise ratio of the output signal is considerably improved. Especially in the case of slow movements of a smooth yarn, the moving member will generate a strong output signal via the converter element. Any movement of the yarn results in a movement of the support surface and the movably supported member relative to one another, resulting in a relatively great amplitude of the converter element output signal even at low yarn speeds. Even in the case of aggravating exterior influences a reliable differentiation between the stationary state and movement of the yarn is possible, and that is substantially independent of the quality and speed of the yarn. It is not the relatively high contact pressure exerted by the yarn on the support surface which is the decisive criterion, but rather the movement of the member relative to the support surface caused by the movement of the yarn and used for generating the output signal.
When the member is subjected to a biasing force acting thereon, preferably in a resilient manner, in the direction towards the support surface, it will always tend to rapidly return to the support surface after having been moved away therefrom, resulting in conspicuous movements of the member relative to, or even impacts thereof on, the support surface, to thereby unequivocally inform the converter element of the fact that the yarn is moving. However, as long as the yarn is not moving, the biasing force acts to keep the member very still, resulting in a distinctive difference detectable by the converter element.
When the member cooperates with the support surface to simultaneously act as a yarn brake for the yarn the longitudinal movement of which is to be monitored, the usefulness of the apparatus is considerably broadened. Although in this case the apparatus occupies only a very small space, it is capable of performing a dual function, which is highly advantageous in view of the frequently very restricted accommodation space. A yarn brake is required in many cases. When the apparatus itself is capable of performing the yarn brake function, it is possible to do without an additional yarn brake.
When the support surface is provided on a yarn guide ring of the yarn guide unit, and the member is a ball engaging the yarn guide ring at its downstream side and having a diameter which is greater than the interior diameter of the yarn guide ring, the construction of the apparatus for detecting a longitudinal yarn movement is considerably simplified, while the apparatus is readily capable of performing the additional function of a yarn brake. When thus employing a ball as the movable member, a constant and uniform signal generating function is ensured irrespective of the location of the yarn in the yarn guide ring.
A structurally advantageous embodiment of the apparatus makes use of a metal ball biased into preferably axial engagement with the yarn guide ring by a magnetic field. The magnetic field offers the advantage that the metal ball member is always attracted toward the yarn guide ring as by an invisible spring, and that the yarn may pass through the yarn guide ring at any circumferential location without contacting any part of the apparatus other than the yarn guide ring and the metal ball member. The metal ball member is nevertheless prevented from dropping out, because the magnetic force acts uniformly in all directions and always tends to attract the metal ball member towards the yarn guide ring in the axial direction.
Under these aspects it is advantageous to arrange a plurality of magnets about the yarn guide ring so as to be radially adjustable. Since the magnets are disposed at the upstream side of the yarn guide ring, they generate a biasing force acting on the metal ball member in the axial direction towards the yarn guide ring, resulting in the advantage that the return movement of the metal ball member after its displacement by the yarn is very distinctive, or even that the metal ball member impacts on the support surface of the yarn guide ring. This permits readily detectable signals to be generated. The radial adjustability of the magnets permits the biasing force of the member to be accurately selected.
In a preferred embodiment the yarn guide ring consists of a ceramic material, the yarn guide unit comprises resilient suspension means for the yarn guide ring, and the converter element is a piezo-electric sensor connected to the yarn guide ring and embedded in the resilient suspension means. The contact pressure of the member displaced by the yarn or the impacts of the member are transmitted to the converter element without any delay and without losses, resulting in the immediate generation of a strong output signal.
It is also advantageous that the engagement force of the member is adjustable so as to permit the amplification of the output signal and/or the yarn braking action to be varied. In this manner it is possible to readily adapt the apparatus to given yarn qualities and yarn speeds. It is also possible to selectively adjust the response threshold of the apparatus.
An alternative embodiment is characterized in that the movable member consists of a metal or contains a metal insert, and that the converter element is a stationarily mounted proximity sensor directed onto the movable member. In this embodiment it is not absolutely necessary that the movable member impacts on the support surface in the course of its movements caused by the yarn. It is rather sufficient for the movable member to be displaced relative to the proximity sensor to thereby cause the latter to generate an output signal which is substantially stronger than the noise signal generated when the yarn is not moving.
BRIEF DESCRIPTION OF THE DRAWINGS
Embodiments of the subject matter of the invention shall now be described by way of example with reference to the drawings, wherein:
FIG. 1 is a cross-sectional, view taken along the line I--I in FIG. 2 detecting a yarn movement, which is at the same time useful as a yarn brake,
FIG. 2 is an end view of the apparatus of FIG. 1 in the direction of a yarn passing therethrough, and
FIG. 3 is sectional view of the apparatus of FIG. 2, taken along the line III--III.
FIG. 4 is a view corresponding to a fragment of FIG. 1, and illustrating a modification in which a proximity sensor is used.
DESCRIPTION OF PREFERRED EMBODIMENTS
According to FIG. 1, an apparatus 1 devised both for detecting a yarn movement and for braking the yarn comprises a cup-shaped aluminum or plastic housing 2 having a central axial bore 3. Fixedly secured in bore 3 is a ceramic inlet guide bushing 4. Disposed downstream of inlet guide bushing 4 in the running direction of a yarn 5 is a yarn guide unit 6 provided with a suspension ring 7 made of an elastic material and connected to housing 2. Mounted in suspension ring 7 is a ceramic guide ring 8. Provided downstream of yarn guide unit 6 in the yarn running direction is a radially symmetric seat 9 having a conical inner bore coaxially aligned with bore 3 and serving for threading the yarn 5 therethrough. Guide ring 8 is formed with a rounded transition between its cylindrical inner surface and its end faces so as to ensure the smooth passage therethrough of yarn 5 and to provide a rounded support surface for the yarn and a member 10 disposed at the yarn exit side of the guide ring. Member 10 is for instance a metal ball the diameter of which is greater than the interior diameter of the guide ring. Member 10 is subjected to the action of a magnetic field biasing it in the axial direction opposite the yarn running direction towards the support surface of guide ring 8. The magnetic field is generated by for instance two bar magnets 11, 12 disposed at the yarn entry side of guide ring 8 at radially aligned positions with respect to the axis of bore 3. As shown in FIGS. 1 and 2, bar magnets 11, 12 are retained in groove-shaped recesses 13 of housing 2 so as to be radially adjustable relative to the axis of bore 3 to thereby permit the strength of the magnetic field acting on member 10 to be selectively varied. The strength of the magnetic field determines the contact pressure between member 10 and the support surface of yarn guide ring 8, and thus likewise the braking action exerted by member 10 on yarn 5. Referring to FIG. 1, the downstream end of the guide ring 8 provides a seat onto which the member 10 is urged by the magnetic field.
Additionally mounted in housing 2 is a soft-magnetic annular disc 14 for focussing the magnetic field.
As shown by dash-dotted lines in FIG. 1, member 10 may be displaced to a radially off-center position in the internal bore of seat 9 to thereby facilitate the threading of yarn 5.
According to FIG. 3, ceramic guide ring 8 has an extension 18 to which a piezo-electric converter element or transducer 15 is adhesively secured. Element 15 has terminals 16 for connection to a circuit board 17 for the pre-amplification of the output signal which in its amplified state is applied to a not shown evaluator circuit.
The biasing force acting on member 10 may also be supplied by a spring element or the action of gravity.
In the described embodiment the yarn guide unit 6 is provided with a stationary guide ring 8. In a modification it is also possible to employ a centrally mounted stationary member with the yarn guide unit movably mounted relative thereto. This arrangement will also result in the effect that the movement of the yarn guide unit relative to the stationary member produces a mechanical amplification of the converter signal. The only thing that matters is that the longitudinal movement of the yarn results in a movement of the member and the support surface relative to one another, the output signal resulting from this movement being more distinctive than the signal resulting from the movement of the yarn relative to the support surface.
It is also conceivable to employ other converter elements, for instance capacitive proximity sensors, inductive elements for detecting relative movements or any other elements known in the art for generating a signal indicative of the movement of two bodies relative to one another.
The member 10 may also assume the form of a cone or a wedge rather than a spherical shape. It is not either absolutely necessary that the member 10 and/or the yarn guide unit 6 be of rotation-symmetrical configuration, it being also possible to employ a mirror-symmetrical configuration relative to a symmetry plane. It is solely of decisive importance that the member which is movable relative to the support surface of the yarn guide unit contacts the yarn simultaneously with the yarn guide unit itself, so that the longitudinal movement of the yarn necessarily results in a movement of the member and the yarn guide unit, or its support surface, respectively, relative to one another. Possible embodiments of the member and the yarn guide unit include for instance curved slide surfaces engaging the yarn at opposite sides, or cylindrical elements likewise engaging opposite sides of the yarn. Also conceivable are non-symmetrical configurations of the movable member and the yarn guide unit.
In addition to its function of detecting the longitudinal yarn movement, the apparatus 1 is also capable of acting as a yarn brake, because yarn 5 has always to be pulled through the gap between the member 18 and the support surface defined by guide ring 8, the biasing force acting on member 10 resulting in a yarn braking action. On the one hand, the biasing force, the magnitude of which is adjustable as explained above, determines the strength of the output signal in cooperation with the mass of the member. On the other hand, the biasing force also determines the braking action capable of being generated by the action of apparatus 1 as a yarn brake. The adjustment of the biasing force thus permits both the output signal amplification and the yarn braking action to be varied, the above mentioned modifications of constructions and shapes of the cooperating components making it possible to determine beforehand the relative magnitudes of the output signal amplification effect and/or the yarn braking effect.
In the embodiment shown, member 10 is in contact with the support surface of yarn guide ring 8 as long as yarn 5 is not moved. This mutual engagement may be in the form of a point contact. Member 10 acts to hold yarn 5 in contact with the support surface. Converter element 15 generates a noise signal, which is relatively weak, however. As soon as yarn 5 is imparted a longitudinal movement through bore 3, member 10 is displaced relative to the support surface, the biasing force constantly acting thereon during its movements causing it to repeatedly impact on the support surface. Converter element 15 responds to these alternating movements and impacts of member 10 and generates an output signal clearly distinctive from the noise signal. When a proximity sensor is employed, it is not necessary for the member to constantly or repeatedly contact the support surface, inasmuch as the proximity sensor is capable of generating a distinctive output signal in response to the relative movements of the member.
Referring to FIG. 4, the proximity sensor 15' detects whether the member 10 moves toward or away from the sensor 15' and thus generates a signal which represents the movement of member 10 under the influence of yarn 5 and consequently the movement of the yarn.
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An apparatus for detecting a yarn movement comprises a yarn guide unit for the sliding guidance of a moving yarn, and a converter cooperating with the yarn guide unit for generating an electric signal. With the aim of improving the signal-noise ratio of an apparatus of this type, there is provided a member mounted for movement relative to the yarn guide unit and disposed such that the yarn is guided between the member and the yarn guide unit in simultaneous contact with the member and the yarn guide unit, the member being subjected to a biasing action relative to the yarn guide unit.
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BACKGROUND OF THE INVENTION
The present invention relates to a fiber lubricant composition which is particularly useful for lubricating a spunbonded nonwoven fabric and to fibers and fabrics having said lubricant composition thereon.
More specifically the fiber lubricant composition of this invention consists essentially of a synergistic mixture of certain silicone-glycol copolymers and butyl stearate which, when applied to spunbonded nonwoven polypropylene carpet backing, provides unexpectedly good lubrication for needle-tufting of the backing and an unexpectedly low flammability of a tufted carpet produced therefrom.
A spunbonded fabric is a continuous filament nonwoven fabric made by combining all the steps from polymer preparation to finished fabric in one process. Curtains of polymer filaments are extruded, drawn, forwarded to a belt and combined there into a web with the required design. The web is then bonded and can be finished in the same single process.
The basic process steps for making spunbonded nonwoven fabrics are quite simple. Multiple spinnerettes extrude large numbers of polymer filaments which are drawn and oriented in groups, by rolls or by high velocity air, and then projected, in some desired geometrical array, as a web onto a slowly moving porous belt provided with suction to hold the web. The belt then carries the web to a bonding operation such as binder application and/or heater rolling and then to one or more further operational steps in the process. These latter steps can be the traditional textile finishing steps such as printing or embossing when process speeds are compatible.
There are many spunbonded nonwoven fabrics available commercially. Examples of such materials are those based on synthetic fibers, such as polyesters, polyamides and polyolefins, such as polypropylene, polyethylene, or combinations of the foregoing. The particular fiber type used will depend on the nature of the finished product one wishes to make. Each uses for spunbonded nonwoven fabrics ranges from such things as book covers, to clothing fabric to carpet backing.
One of the most significant commercial uses of spunbonded nonwoven fabric is the use of spunbonded nonwoven polypropylene as a carpet backing. The spunbonded nonwoven polypropylene fabric has been substituted for the woven jute backing materials that have been used heretofore in the production of carpets.
In this use the carpet yarn is threaded through a suitably large needle which is then punched through the spunbonded nonwoven polypropylene fabric, designated as the primary backing. A looper device catches the yarn on the opposite side of the backing to form loops or tufts and the yarn and needle are then withdrawn to complete the formation of the loop or tuft. The backing fabric is then advanced and the cycle is repeated to form additional tufts. The tufts make up the pile or face of the final carpet. A commercial tufting machine may have up to 2400 needles in a row all working in unison to make a carpet up to 15 feet in width.
The primary backing, which is the spunbonded nonwoven polypropylene fabric, is the structural base of the carpet. It holds the tufts in place and provides dimensional stability and strength to the carpet. To the back of the tufted spunbonded nonwoven polypropylene backing there is applied a glue, for example a latex of natural rubber or styrene-butadiene rubber, which coating firmly anchors the tufts in place and keeps them from pulling out. A jute or foam back may then be placed on the glued carpet backing to act as a pad or cushion.
In the development of this use of the spunbonded nonwoven fabric it was found that the needles did extensive damage to the carpet backing on penetration of the structure, resulting in a large loss in strength during the tufting process.
Campbell, et al., U.S. Pat. No. 3,867,188 discovered that when certain silicone-glycol copolymers were applied to the spunbonded nonwoven polypropylene backing the penetration of the needle therethrough in the tufting process was facilitated and the backing damage and its attendant loss of strength could be significantly reduced.
Useful as Campbell et al's discovery is, it suffers from a drawback common to previous processes comprising using a silicone as a lubricant for spunbonded nonwoven carpet backing, i.e. increased flammability of certain carpeting produced therefrom. It appears that as the carpet yarn is punched through a carpet backing that has been lubricated with a silicone-containing composition it picks up some of the lubricant composition, thereby resulting in a carpet having the lubricant composition on its facing as well as on its backing. It is thought that, at certain levels of add-on, silicone compositions are responsible for the enhanced flammability of some thermoplastic yarn materials, that is demonstrated in some testing procedures.
SUMMARY OF THE INVENTION
It is an object of this invention to provide a silicone-glycol-containing composition which is useful for lubricating spunbonded nonwoven carpet backing but which does not increase the flammability of a carpet prepared by needle-tufting a spunbonded nonwoven carpet backing treated therewith. It is a further object of this invention to provide an improved spunbonded nonwoven polypropylene carpet backing. It is another object of this invention to provide an improved spunbonded nonwoven fabric. It is an additional object of this invention to provide an improved fiber.
These objects, and others which will become obvious to one considering the following specification and appended claims, are obtained by preparing a mixture consisting essentially of from 1.0 to 9.0 parts by weight of butyl stearate and 1.0 parts by weight of the silicone-glycols disclosed by Campbell et al. in U.S. Pat. No. 3,867,188 and applying the resulting composition to a fiber, such as those of a spunbonded nonwoven fabric.
It was surprising to discover that such a mixture, when applied to a spunbonded nonwoven polypropylene carpet backing at a concentration of approximately 1 percent by weight, based on the weight of the carpet backing, would not increase the flammability of a carpet prepared from the resulting polypropylene backing.
While this invention is not to be limited by theory, it is believed that the compositions of this invention operate, with respect to their carpet flammability behavior, by simply allowing a small amount of silicone-glycol copolymer to be applied to the polypropylene carpet backing, thereby not contributing to the flammability of a carpet produced therefrom.
However, it was completely unexpected to find that the compositions of this invention provide a level of lubrication of the spunbonded nonwoven carpet backing which exceeds that obtained when either butyl stearate or the silicone-glycols of Campbell et al. noted above are applied alone to the spunbonded nonwoven backing.
DETAILED DESCRIPTION OF THE INVENTION
This invention relates to a composition consisting essentially of (a) 1.0 part by weight of a silicone-glycol copolymer having the formula
(CH.sub.3).sub.3 SiO{(CH.sub.3).sub.2 SiO}.sub.x {(CH.sub.3)(G)SiO}.sub.y Si(CH.sub.3).sub.3
wherein G denotes a silicon-bonded radical having the formula --R(OC 3 H 6 ) z OH, R denotes an alkylene radical containing from 1 to 18 carbon atoms, x has an average value of from 40 to 90, y has an average value of from 1 to 10 and z has an average value of from 1 to 10, and (b) from 1.0 to 9.0 parts by weight of butyl stearate.
This invention also relates to a spunbonded nonwoven fabric having thereon a composition of this invention.
This invention further relates to a spunbonded nonwoven polypropylene carpet backing having thereon an amount of the compositions of this invention, said amount being sufficient to place on the carpet backing from 0.05 to 0.5 parts by weight, based on 100 parts by weight of the carpet backing, of the silicone-glycol copolymer component in the compositions of this invention.
This invention still further relates to a fiber having thereon a composition of this invention.
The silicone-glycol copolymer which is used in the compositions of this invention is a trimethylsilyl endblocked siloxane which contains from 40 to 90 dimethylsiloxane units and from 1 to 10 methylglycolsiloxane units. The copolymers useful herein are water-insoluble because the water-soluble silicone-glycol copolymers, when used in the preparation of needle-tufted carpet, allow the subsequently applied latex glue to wet and penetrate the polypropylene backing too far, resulting in a poor carpet.
The glycol radicals of the methylglycolsiloxane units are represented in the copolymer formula by the symbol G which is more specifically defined as having the formula --R(OC 3 H 6 ) z OH. The R radical in this formula can be any alkylene unit containing from 1 to 18 carbon atoms. Thus, for example, R can be a methylene, ethylene, propylene, butylene, isobutylene, hexylene, decylene, dodecylene or an octacdecylene radical. The glycol portion represented by the (OC 3 H 6 ) z portion of the structure is, as can be seen from the formula, an oxypropylene radical. The glycol radical is hydroxyl endblocked or, as is commonly stated in the art, an uncapped glycol. As indicated there can be an average of from 1 to 10 oxypropylene units making up the glycol portion of the structure, i.e., z has an average value of from 1 to 10. It is preferred, however, that z have an average value of from 1 to 5.
The average number of methylglycolsiloxane units in the silicone-glycol copolymer can range from 1 to 10 which is to say y can have an average value from 1 to 10. However, it is generally preferred that the average value of y be in the range of from 1 to 5. The subscript x can have an average value of from 40 to 90, but preferably ranges in value from 50 to 75. The subscript x defines the average number of dimethylsiloxane units in the silicone-glycol copolymer.
Based on the disclosure of the structure herein the preparation of the silicone-glycol copolymer set forth above will be obvious to those skilled in the art of the preparation of such materials. Preferably said silicone-glycol copolymer is prepared by first preparing a siloxane of the structure Me 3 SiO(Me 2 SiO) x (MeHSiO) y SiMe 3 in the well-known manner and thereafter reacting therewith, in the presence of a platinum-containing hydrosilylation catalyst, an unsaturated glycol such as a glycol having the formula CH 2 ═CHCH 2 (OC 3 H 6 ) z OH, in sufficient quantity to react with all silicon-bonded hydrogen atoms on the siloxane. The resulting silicone-glycol copolymer is substantially free of silicon-bonded hydrogen radicals.
A preferred siloxane-glycol copolymer component in the compositions of this invention has the formula
(CH.sub.3).sub.3 SiO{(CH.sub.3).sub.2 SiO}.sub.67 {(CH.sub.3)(HO(C.sub.3 H.sub.6 O).sub.2.5 -CH.sub.2 CH.sub.2 CH.sub.2)SiO}.sub.3 Si(CH.sub.3).sub.3.
Examples of other suitable silicone-glycol copolymers useful herein include ##STR1##
Butyl stearate is a well-known oleaginous liquid which is soluble in alcohol but substantially insoluble in water. It is commercially available in various grades such as technical grade, cosmetic grade and chemically pure grade. All of these grades of butyl stearate are suitable for use in this invention. Butyl stearate is a well-known component of fiber lubricant, polish, coating, cosmetic, pharmaceutical and textile-treating compositions. Its identity and uses need no further elaboration here.
The compositions of this invention are single phase, homogeneous mixtures which can be prepared by any suitable method, such as by simple, but thorough, mixing of the components thereof.
The compositions of this invention may contain non-essential components such as volatile diluents to provide emulsions or solutions thereof and trace amounts of colorants, odorants and other adjuvants which are common to textile-treating compositions.
A preferred composition of this invention for treating spunbonded nonwoven carpet backing consists essentially of 1.0 part by weight of the preferred siloxane-glycol copolymer, detailed above, and 21/3 parts by weight of butyl stearate.
The compositions of this invention can be applied to a fiber or to a fabric by any of the well-known techniques such as padding, rolling, spraying and dipping. To assure a desirable degree of fiber-bonding, the fibers of a spunbonded fabric, such as those of a carpet backing, should be treated with the compositions of this invention after the fiber-bonding operation has been completed.
The amount of the compositions of this invention that is applied to the fiber or fabric will depend to some extent on the desired results but generally speaking will fall within the range of 0.1-10 percent by weight based on the weight of the fiber or fabric. However, it is believed that generally an amount in the range of 0.5-5 percent will meet most needs.
To confer desirable reduced-flammability characteristics to a polypropylene carpet made from a spunbonded nonwoven carpet backing of this invention the composition of this invention should be applied to the carpet backing in an amount that will place, on the carpet backing, from 0.05 to 0.5 parts by weight of the silicone-glycol component for every 100 parts by weight of the spunbonded nonwoven carpet backing.
The compositions of this invention are useful for lubricating synthetic fibers, such as monofilament threads, polyfilament threads, yarns and tows and staple that are used to prepare woven, knitted and sewn fabrics. The compositions of this invention can be applied to a fiber before or after it is used to prepare a woven, knitted or sewn fabric.
The following examples are disclosed to further illustrate, but not limit, the present invention. All parts and percentages are by weight unless otherwise stated. Me denotes the methyl radical. Percent pick-up for fiber-lubricating composition by the carpet backing is based on the weight of the carpet backing.
Pill Test
Flammability of a needle-tufted carpet sample was measured by this test wherein a methenamine fuel pill is placed in the center of a 12"×12" carpet sample, previously dessicated and placed on a flat horizontal support, and ignited. A pass rating is given to the carpet if the region of burning does not extend beyond a distance of three inches from the pill.
Tongue Tear Test (TTT)
Lubrication of a needle-tufted carpet sample was measured by this test. Higher values of TTT show greater lubrication of the backing.
The tufted non-woven sheet is cut into a sample 6 inches wide (cross-machine direction, across tufting rows) and 8 inches long (machine direction, along tufting rows). The sample is cut in the center of the width 4 inches in the machine (tufting) direction. The sample is mounted in an "Instron" tester using 1.5 inch by 2 inch serrated clamps. With a jaw separation of 3 inches, one side of the sample cut is mounted in the upper jaw and the other side of the sample cut is mounted in the lower jaw. The sample is uniformly spaced between the jaws. The full scale load is adjusted to a value greater than the tear strength expected for the sample. Using a cross head speed of 12 inches per minute and a chart speed of 10 inches per minute, the "Instron" is started and the sample is torn. An average of the three highest stresses during tearing is taken. The tongue tear strength in pounds is reported as this average divided by 100 and multiplied by the full scale load. In general several determinations are made and the average reported.
Tufted Grab Tensile (TGT)
Effective lubrication of a carpet backing to reduce fiber breaking during needle-tufting without reducing tuft retention is measured by this test. Higher values of TGT show greater lubrication fo the backing.
A tufted sample is cut into samples 4 inches wide by 6 inches long in the tufting direction. The sample is mounted in an "Instron" using a 1 inch by 2 inch clamp on the back side and a 1 inch square clamp on the front side at a jaw separation of 3 inches. A crosshead speed of 12 inches per minute is used. The peak of the "Instron" curve is read and reported as pounds breaking strength.
EXAMPLES
A silicone-glycol copolymer having the approximate average formula ##STR2## was mixed in various amount with five portions of butyl stearate to provide five compositions of this invention containing 9, 4, 21/3, 11/2 and 1 parts, respectively, of butyl stearate for every part of siloxane-glycol copolymer.
Seven pieces of spunbonded nonwoven polypropylene carpet backing, designated as Typar®-3301 by E. I. DuPont de Nemours and Co., Inc., were coated, using a gravure roll, with one of the above compositions of this invention or butyl stearate or the silicone-glycol copolymer noted above. An eighth sample of carpet backing was not coated.
The coated and noncoated carpet backing samples were needle-tufted with a 1/10 guage needle fitted with 2600 denier Herculon® brand polypropylene yarn, 10 tufts per inch, to provide a carpet sample having a pile height of 1/4". The resulting carpet samples were examined for flammability, using the Pill Test, and for lubricity using the Tufted Tear Tensile and Tufted Grab Tensile tests, all described above. These samples and test data are summarized in the Table.
The compositions of this invention (reference numbers 2 through 6) provide a greater amount of lubrication, as measured by the Tufted Grab Tensile Test than either of their components (reference numbers 1 and 7). Those carpet samples that were prepared from fabrics of this invention having no more than 0.5 percent silicone-glycol copolymer on the fabric (reference numbers 2 through 5) were no more flammable than the control carpet or the carpet having only butyl stearate on its backing (reference number 1).
TABLE__________________________________________________________________________Carpet-Backing Finish Test ResultsRef. Composition, parts Pick-up, Flammability, Tufted Grab Tufted TearNo. Silicone-glycol Butyl stearate % No. Pass/No. Fail Tensile, lbs. Tensile, lbs.__________________________________________________________________________Control0 0 0 8/0 16 71/21.sup.(1)0 1 1.8 8/0 34 212 1 9 1.2 8/0 64 273 1 4 1.2 8/0 75 354 1 21/3 1.0 8/0 83 395 1 11/2 1.2 8/0 70 416 1 1 1.5 5/3 64 427.sup.(1)1 0 1.2 4/4 56 40__________________________________________________________________________ .sup.(1) Reference numbers 1 and 7 are for comparative purposes only.
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Fiber lubricant compositions having unusual lubricating properties for spunbonded, nonwoven polypropylene carpet backing are disclosed. A needle-tufted carpet, prepared from a carpet backing bearing a composition of this invention, has unexpectedly high strength and unexpectedly low flammability. The compositions of this invention comprising a mixture of butyl stearate and certain silicone-glycol copolymers, are useful as a lubricant for synthetic fibers, in general.
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TECHNICAL AREA
[0001] The present invention relates to a holding means for holding and protecting a movable connector part of a hydraulic system.
BACKGROUND OF THE INVENTION
[0002] Hydraulic systems are used in a wide variety of applications. One application relates to work vehicles, such as wheel loaders or tractors, to which a work equipment, such as front loader, a plough, a bucket or similar, my be connected. A part from being mechanically connected to the work vehicle, the work equipment also needs to be hydraulically connected. The work equipment includes a hydraulic system for controlling its functions. This hydraulic system is connected to and driven by the hydraulic system of the work vehicle.
[0003] The two hydraulic systems are interconnected by means of connector parts. The connectors are preferably of a multi coupling type, in which a plurality of hydraulic connections may be connected in one single operation. A multi coupling comprises a fixed part on the vehicle and a movable part on the work equipment. It is however still common to connect each and every hydraulic connection individually, usually by means of so called quick couplings, one for every connection. In this application a “fixed connector part” denotes the connector on the work vehicle regardless of if it is of a multi coupling type or of comprises a plurality of individual couplings. Accordingly, application a “movable connector part” denotes the connector on the work equipment regardless of if it is of a multi coupling type or if it comprises a plurality of individual couplings.
[0004] It is important for the well function of these connectors that they are kept clean, both during working operations, but also in between working operations. The work vehicle often operates in harsh environments, in which the connector parts are exposed to dirt. Thus, there exists a need for an arrangement for protecting the connector parts of the hydraulic systems. As the work vehicle sometimes is operated without work equipment the protective arrangement needs to adaptable, such that it also protects the fixed connector part and the movable connector part individually when they are disconnected from each other.
[0005] Conventionally, the fixed connector part has been provided with a pivotable lid, which is arranged to cover the fixed connector part when no movable connector part is connected to it. To connect the movable connector part, the cover is folded open to make room for the movable connector part. This conventional type of cover protects the fixed connector part satisfactory when it is left disconnected. However, other than that it has a number of disadvantages. Firstly, the cover collects dirt during operation as the lower protective surface of it is left exposed to the environment during normal operation. Thus the cover has to be cleaned each time it is to be remounted on the fixed connector part. Additionally, no protection is provided for the movable connector part when it is disconnected from the fixed connector part. Normally, the work equipment with the exposed movable connector part is stored in a rather dirty environment, often outside. Thus it is not uncommon that the movable connector part needs to be cleaned before it is connected to the fixed connector part.
BRIEF DESCRIPTION OF THE INVENTION
[0006] An aim of the present invention is to provide an improved arrangement for keeping the connector parts clean.
[0007] This is achieved according to the present invention by the holding means of claim 1 . Preferable embodiments of the present invention are indicated in the dependent claims.
[0008] According to a main aspect, the invention relates to a holding means for protecting a movable connector part of a hydraulic system on a work equipment, which movable connector part is connectable to a fixed connector part of a hydraulic system on a work vehicle, the holding means having an contact surface being adapted to fit tightly on the movable connector part such that its hydraulic connections are protected and unexposed when the movable connector part is placed in the holding means. The holding means is adapted to be fixedly arranged on a work equipment, such that the contact surface of the holding means is accessible for protective connection of the movable connector part.
[0009] An advantage of the present invention is that the movable connector part is kept clean in between operations, such that it does not have to be cleaned before use.
[0010] Further, a second advantage of the invention is that thanks to the holding means the movable connector part of the work equipment is protected from impact as long as it is parked in the holding means. In prior art where there was no provision for protecting the movable connector part when disconnected from the fixed connector part there was always a risk that it might be damaged in one way or another. This risk is clearly minimised with the holding means according to the invention.
SHORT DESCRIPTION OF THE DRAWINGS
[0011] In the following detailed description of the invention, reference will be made to the accompanying drawings, of which:
[0012] FIG. 1 shows a work vehicle provided with a fixed connector part, wherein a work equipment with a movable multi coupling part is arranged on the work vehicle;
[0013] FIG. 2 shows a detailed view of the fixed connector part of FIG. 1 ;
[0014] FIG. 3 shows a work vehicle with a disconnected work equipment;
[0015] FIG. 4 shows a detailed view of the fixed connector part of FIG. 3 provided with a cover according to an embodiment of the invention;
[0016] FIG. 5 shows a detailed view of the movable connector part of FIG. 3 , parked in a holding means according to the invention;
[0017] FIG. 6 shows the holding means in detail;
[0018] FIG. 7 shows the holding means and three sets of connectable fittings;
[0019] FIG. 8 shows the movable connector part parked in the holding means;
[0020] FIG. 9 shows a movable connector part in form of 4 individual hydraulic couplings and an electric connector parked in the holding means;
[0021] FIG. 10 shows a movable connector part in form of 2 individual hydraulic couplings and an electric connector parked in the holding means;
[0022] FIG. 11 shows a cover arranged on the holding means.
DETAILED DESCRIPTION OF THE INVENTION
[0023] FIG. 1 shows a schematic view of a work vehicle 1 , i.e. a tractor, provided with a conventional hydraulic system comprising a hydraulic pump, a tank with hydraulic fluid and a number of conduits, connections and valves. The hydraulic system comprises a fixed connector part 10 , which is adapted to be connected to a movable connector part of a hydraulic system of a work equipment 2 to be used on the work vehicle 1 . In FIGS. 1-5 the movable connector part is represented by a movable multi coupling part 20 .
[0024] Often, a work vehicle 1 is used for a number of different work tasks involving different work equipments 2 . In the figures, the work equipment 2 is exemplified by a front loader unit, which is releasably attached to the work vehicle 1 . In addition to the movable connector part 20 , the front loader is provided with a movable hydraulic system comprising connections, conduits and pistons for lifting the loader and tilting the bucket. Generally, different types of equipments are adapted to be releasably attached to the work vehicle 1 . Hence, the hydraulic connection unit of the work equipments 2 , i.e. the movable connector part, must be adapted to be connected to/disconnected from the fixed connector part 10 of the hydraulic system on the work vehicle 1 . Additionally, different tools may be connected to the work equipment 2 . The tools generally also include hydraulic systems, which systems need to be connected to the hydraulic system of the work vehicle, via the hydraulic system of the work equipment 2 . These connections might or might not be of the same type as the connections between the work equipment 2 and the work vehicle 1 . For the sake of simplicity, only the connection between the work equipment 2 and the work vehicle 1 is described in this application. The invention may however also be used at the connection between the work equipment 2 and the tool.
[0025] FIGS. 1-2 show the work vehicle 1 when the work equipment 2 is arranged on it. In this state, the movable multi coupling part 20 is connected to the fixed connector part 10 , and a cover 40 is arranged to protect a holding means 30 , which is arranged on the work equipment 2 .
[0026] In FIGS. 3-5 , the work equipment 2 is disconnected from the work vehicle 1 . In this state the movable multi coupling part 20 is parked in the holding means 30 , and the cover 40 is instead arranged on the fixed connector part 10 in order to protect it.
[0027] The main aspect of the invention concerns the holding means 30 or “parking slot”, which is adapted to be arranged on the work equipment 2 on a suitable location where it does not interfere with the function of the work equipment. The holding means 30 is designed such that it mates with the movable multi coupling part 20 . Thus, it resembles the fixed connector part 10 and comprises an contact surface 32 arranged to correspond to and co-act with the connection surface of the movable multi coupling part 20 , in order to protect the connection surface of the movable multi coupling part when attached to the holding means 30 . The holding means 30 in the shown embodiment is provided with a central bar 33 corresponding to a bar of the embodied fixed hydraulic connection part 10 . The holding means 30 is further provided with a circumferential rim 31 , inside which the movable multi coupling part 20 fits tightly, such that it is efficiently held at place without any possibility to rotate. Preferably, the rim 31 also defines the outer border of the contact surface 32 . Thus, the rim functions as a protective limit, keeping dirt away from the contact surface.
[0028] When the work equipment 2 is not to be used any more, the movable multi coupling part 20 is disconnected from the fixed connector part 10 on the work vehicle and inserted into the holding means 30 in which it fits tightly and remains fixed. The movable multi coupling part 20 is thus kept out of the way and is at the same time protected from the environment, such that dirt, debris, ice, snow etc. is kept away from its connection surface. Conventionally the connection part of the work equipments have been left exposed to the environment, which of course may lead to all kinds of problems, including total failure of the connector part due to impact with neighbouring objects, and heavy soiling of both the connector part and the environment due to spillage of hydraulic fluid.
[0029] As indicated above, not all work equipments 2 are provided with a movable connector part of a multi coupling type. Therefore, the holding means 30 according to the invention is also adapted to receiving conventional hydraulic quick couplings. Openings 34 a - d are arranged in the holding means 30 , which are dimensioned to house individual quick couplings 24 a - d , see e.g. FIG. 9 or 10 . Hence, if the work equipment 2 is furnished with individual quick couplings 24 a - d instead of a movable multi coupling part 20 , these may be individually housed in these openings 34 a - d of the holding means 30 . Often, en electric connection is integrated in the fixed connector part for supplying the work equipment with electricity. Therefore, the holding means is provided with a dummy 33 arranged for attachment of such an electric connection of the work equipment.
[0030] In the shown embodiment the electric connection is covered by a housing 25 which fits on the central dummy 33 .
[0031] Consequently, a holding means 30 is advantageously arranged on all work equipments 2 that include a hydraulic system, regardless of the type of connection the hydraulic system of the work equipment 2 is provided with.
[0032] A second protecting means, in form of a cover 40 , is provided in accordance with the present invention on the one hand for protecting the fixed connector part 10 when the movable connector 20 , 24 a - d part is not connected to it, and on the other for protecting the holding means 30 when the movable connector part is connected to the fixed connector part 10 . The cover 40 is arranged as a lid with a lower surface that corresponds to the lower surface of the movable connector part 20 , such that it fits the upper surface of the fixed connector part 10 and the upper surface of the holding means 30 . The cover 40 may further be arranged with a central sleeve which protrudes through an opening in the cover, and is connected to a knob 41 for turning the sleeve around its longitudinal axis. The sleeve may have the same configuration as the sleeve of the movable connector part 20 , which enables the sleeve to be attached to the central bar 13 of the fixed connector part 10 in order to protect the hydraulic connections of the fixed connector part 10 when it is not in use. On the other hand, when the hydraulic system of the equipment is connected to the hydraulic system of the work vehicle, the cover is attached to the holding means 30 in order to protect the holding means 30 from dirt and debris. Thus, the holding means 30 and the cover 40 provides a full protection of the hydraulic connection parts of the present invention both during use and when parked.
[0033] As the cover is intended to be transferred between the fixed connector part and the holding means it may not fixed to either of these. However it may preferably be attached to the work vehicle by means of a strap or similar. This is conceivable as the cover 40 is only attached to the holding means 30 when the work equipment with the holding means is attached to the work vehicle 1 . When the work equipment 2 is disconnected from the work vehicle 1 the movable connector part 20 is placed in the holding means 30 and the cover 40 is placed on the fixed connector part 10 . It is of course possible within the scope of the claims to use two individual covers, one for the fixed connector part 10 and for the holding means 30 , but for such an embodiment the covers need to be arranged such that they do not collect dirt when they are disconnected.
[0034] In the shown embodiment the holding means and the cover are designed to fit a special embodiment of a movable and a fixed connector part, respectively. As can be readily understood from the above the present invention may however be designed in many ways without departing from the scope of protection as defined by the patent claims. A general idea is that the holding means and the cover should be designed to fit the movable and the fixed connector part of the hydraulic system where it is to be implemented. It is thereby to be understood that the embodiments described above and shown in the drawings are to be regarded as non-limiting examples.
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Holding means ( 30 ) for protecting a movable connector part ( 20; 24 a - d ) of a hydraulic system on a work equipment ( 2 ), which movable 5 connector part ( 20; 24 a - d ) is connectable to a fixed connector part ( 10 ) of a hydraulic system of a work vehicle ( 1 ), the holding means ( 30 ) having a contact surface ( 32 ) being adapted to mate with the movable connector part ( 20; 24 a - d ) such that its hydraulic connections are protected and unexposed when it is placed in the holding means ( 30 ). 10 The holding means ( 30 ) is adapted to be fixedly arranged on the work equipment ( 2 ), such that said contact surface ( 32 ) of the holding means ( 30 ) is accessible for protective connection of the movable connector part ( 20; 24 a - d ).
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[0001] The present invention relates in general to the field of biosensors, and in particular to methods and apparatus for regenerating such sensors, thereby increasing the effective life thereof.
[0002] In a specific aspect the invention relates to a system for continuous analysis of analytes in blood or serum comprising means for regeneration of the sensor employed therein.
BACKGROUND OF THE INVENTION
[0003] Measurements of analytes in blood is commonly performed by sampling blood from patients and analyzing said samples in a laboratory, often situated at a location remote from the ward. E.g. for glucose analysis there are available special reagent sticks usable for measuring on site i.e. in the ward. However, the accuracy of such measurements is questionable, and the error could be 10-20% at best.
[0004] Often it is necessary to perform several sequential measurements over periods of several hours, which is very labor intensive. Furthermore, the risk for errors because of the human intervention is evident, and the low accuracy is of course also a drawback in this regard.
[0005] For the purposes of this application, the term “biosensor” means any device having a portion which interacts with biological or biochemical material, and has the capability to generate a signal indicative of a change in some parameter of said biological or biochemical material as a consequence of said interaction.
[0006] When analytes such as glucose, urea, lactate, ATP, glycerol, creatinine and pyruvate in biological samples, such as blood, plasma or serum are analyzed using biosensor techniques based on immobilization of enzymes, the sensor surface will be exposed to a certain amount of sample during a certain time sufficient to achieve an adequate sensor response. It is well known that the sensor response gradually will degrade because of fouling of the surface. This in its turn is a consequence of said exposure and the interaction between the surface and the substances present in the sample that occurs. The chemical and physical composition of the sample is thereby of importance, the sample i.a. comprising red cells, blood platelets, macromolecules, electrolytes, lipids, red/ox-compounds etc. It is also known that the support material for the enzyme immobilization in biosensors based on enzyme column technology is fouled by the substances present in the sample.
[0007] In cases where selective membranes are used for protection of the sensor surface of biosensors based on enzyme electrode technology, said membranes are also fouled by such substances.
[0008] This fouling influences the sensor response by substantially reducing the life and stability of the biosensor.
DESCRIPTION OF RELATED ART
[0009] Most known metabolite sensors today are based on the amperometric principle, that is measurement of oxygen consumption or hydrogen peroxide production in electrochemical reactions. However, interference with reducing/oxidizing substances causes problems like long time drift, need for frequent calibration and short life. Regarding the sampling procedure there exist devices which, before the actual measurement, condition the blood before it enters the actual sensor by e.g. introducing a special step, such as dialysis. This is both a more complicated solution and also more expensive, since the dialysis cassette has to be replaced before a new measurement can be made.
[0010] Another known sensor principle is by utilizing the heat production when the analytes are decomposed by the appropriate enzyme for the analyte in question. This so called enzyme calorimeter principle is known from U.S. Pat. No. 4,021,307. The enzyme calorimeter disclosed therein is however not suited for direct measurement on whole blood, since the blood cells quickly will clog the column containing the immobilized enzyme, due to adsorption of blood constituents such as various cells, trombocytes, proteins etc. This effect could be circumvented to a certain extent by diluting the blood at least ten times, which will reduce the sensitivity of the measurement considerably. However such a measure would require an extra supply of a diluting solution. Another way of reducing the clogging of the column is to use a special super porous support material with a pore size larger than 10 μm. This support made from agarose, is however softer than the conventional support materials used in this field, preferably glass, and therefore are at a certain risk of (occasionally) being compressed by the blood sample, which in turn quickly will clog the column.
[0011] Thus, at present there is no reliable method and system available for the direct and continuous analysis of whole blood drawn from patients.
SUMMARY OF THE INVENTION
[0012] The present invention therefore seeks to provide an improved method of analyzing whole blood in respect of analytes such as glucose, lactate, urea, ATP, glycerol, creatinine and pyruvate wherein the drawbacks of the prior art methods are alleviated.
[0013] In particular the active life of a biosensor that is used for such analysis is prolonged by providing for reduced fouling of the sensor by regenerating the sensor in accordance with the invention.
[0014] The method according to the invention is defined in claim 1 .
[0015] In a second aspect of the invention there is also provided a system for long time measurements of whole blood directly and continuously sampled from a patient, wherein the flow of the sampled blood is held at a very low rate.
[0016] The system according to the invention is defined in claim 12 .
[0017] Further scope of applicability of the present invention will become apparent from the detailed description given hereinafter.
[0018] 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.
[0019] 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 not limitative of the present invention, and wherein
[0020] FIG. 1 is an overview of a system according to the invention;
[0021] FIG. 2 is a cross sectional view through a connector according to the invention;
[0022] FIG. 3 is a view similar to FIG. 2 , but showing a conventional connector without the inventive sealing feature; and
[0023] FIG. 4 is a flow chart illustrating the sequence of steps in the method of the invention.
DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS
[0024] In FIG. 1 there is disclosed a system for performing a continuous monitoring of the concentration of analytes in blood.
[0025] It comprises a blood sampling device 2 , such as a cannula 4 inserted in a vein of a patient. The cannula 4 is connected to the other system components via a tubing 8 and a suitable connector 6 (to be described) connecting to a pump 10 , which is provided for drawing the various fluids through the system at controlled flow rates. The pump is a multichannel pump, and has a first input 12 for the blood from the sampling device 2 , a second input 14 for buffer solution from a buffer storage 15 , and a third input 16 for anticoagulant from an anticoagulant reservoir 17 . Anticoagulant is fed through a line 9 into the sample flow in line 8 at a point near the tip of the catheter 4 .
[0026] Alternatively there may be provided separate pumps for the various components.
[0027] The valve 20 is important for the operation in accordance with the invention, and has two inputs, one input 21 for sample blood, fed from pump 10 through line 22 , and one input 23 for buffer, fed through line 24 . There are also two outputs, a first connecting to line 25 a feeding the fluid to the analysis portion, and a second connecting to line 25 b for discharging the fluid as waste. The valve 20 is designed such as to permit fluid (i.e. blood in this embodiment) from line 22 to be injected into the buffer flow from line 24 .
[0028] All surfaces in the system exposed to sample are coated with heparin in order to make the system blood compatible.
[0029] The actual sample analysis may be carried out in a so called enzyme reactor (ER) 26 , although it is contemplated that any biosensor type may be used, provided it has a sensitive portion arranged in some kind of flow passage where flow past the sensitive portion of the sensor can be controlled. Thus, a sensor of a type that is merely immersed in a liquid would not be suitable for use with this invention. An ER is used in a preferred embodiment and will be described in more detail below.
[0030] The system also comprises a control unit 50 , which may be a micro processor or a PC. An interface 55 is connected between the control unit 50 and the components in the system, such that control signals to the pump 10 and the valve 20 are fed via lines 52 and 54 respectively. Thus, the pumping rate in the various independently operated flow passages may be increased or decreased, and the valve 20 may be switched between its various positions by commands issued by the control unit in response to signals from the biosensor. An amplifier 56 is provided for amplifying the signals from the biosensor 26 , and feeding said signals to the interface on line 58 , for further transmission to the control unit which uses the information thus obtained to issue the appropriate control commands to the pump and valve.
[0000] The Enzyme Reactor
[0031] An enzyme reactor (ER) 26 comprises a sensor column. The column contains support material such as beads of glass or hard polymer resin, on which enzyme has been immobilized. Immobilization of enzyme is standard procedure and does not form part of this invention, and will hence not be described in detail herein.
[0032] The operation and function of the ER 26 is as follows.
[0033] The sensor column has two thermistors 30 , 32 , one 30 arranged at the column inlet and the other 32 at the column outlet. Fluid entering the column will begin reacting with the enzyme that is immobilized on the beads in the column, and will thereby generate heat, causing the temperature of the fluid to increase. By monitoring the temperatures at the inlet and outlet respectively, and integrating the temperature over time, the integral obtained will correspond to the heat of reaction, which then may be related to the concentration of e.g. glucose in the fluid.
[0034] Because of non-specific reactions that may be exothermic or endothermic and which occur in the column, temperature fluctuation must be accounted for. Thermostating the reactor is one way of doing this, but it can be achieved also in other ways and by other means, and is not crucial to the invention.
[0000] Operation
[0035] Returning now to FIG. 1 , there is illustrated an embodiment of the system which comprises a biosensor 26 arranged in a thermostated environment. The system is operated as follows:
[0036] The catheter 4 is inserted in a blood vessel of a patient, and connected to the tubing of the system by means of a connector 6 (to be described). Initially the pump will draw blood through line 8 via line 22 , through the valve 20 and to the waste line 25 b for disposal, and buffer from buffer storage 15 is drawn via line 18 through the valve 20 and via line 25 a into the enzyme reactor 26 . The continuously measured signals obtained from the sensor when the buffer passes through it will form a background or zero level, and the flow of buffer will be referred to as a “background flow” in this application. The rate of background flow may vary in the range 0.1-10 ml/min., and preferably is 1 ml/min.
[0037] If desired, and indeed it is mostly required, anticoagulant is mixed with the blood. Normally a ratio between sample and anticoagulant of 1:1 will be used, although other ratios are conceivable for specific conditions. The anticoagulant is pumped in line 9 and injected in the sample flow line 8 near the catheter 4 tip.
[0038] At a time when it is desired to make a measurement the valve is given a “SWITCH TO INJECTION MODE” command to the effect that the blood is redirected into the buffer stream, for a period of time of a duration sufficient for an aliquot of 10 μl to be entered as a liquid plug in the buffer stream (other sample volumes may of course be employed, but at the present time 10 μl has proven suitable in most cases). This “blood plug” is passed in line 25 a , which runs in the thermostated medium, where the sample obtains a controlled temperature, and then it enters the ER 26 .
[0039] As soon as the blood, containing e.g. glucose, reaches the ER 26 , the glucose will start reacting with the enzyme, thereby evolving heat of reaction. The enzyme reaction is a very rapid process. Other components in the blood, such as various cells, trombocytes and proteins having a tendency to adsorb to the material inside the reactor, will begin to adsorb. The latter process is however a slow process compared to the diffusion controlled enzyme reaction. The small glucose molecules diffuse very much faster than the macromolecules and other macro components in the blood.
[0040] The thermistor 32 at the output end of the ER 26 will experience a rise in temperature caused by the enzyme reaction occurring in the reactor (at this time the entire sample preferably should have entered the reactor, although this is not absolutely necessary, as will be discussed below).
[0041] In the present embodiment the temperature increase sensed by thermistor 32 is transmitted to the control unit which is programmed to respond to an increase in the temperature signal to issue a INCREASE BUFFER FLOW RATE command to the pump 10 to increase the rate of flow of the buffer by 5-100%, preferably by 10-50%, most preferably by 15-30%.
[0042] By balancing the flow rates, i.e. defining a suitable ratio between background flow rate and increased flow rate, it is possible to create a situation where larger components, such as cells, proteins etc, are washed away before they have had an opportunity to adsorb on the active surfaces inside the ER 26 , and at the same time allow the smaller molecules of interest sufficient time to react with the enzyme to such an extent that it is possible to detect the reaction.
[0043] This balancing of flow ratios within the given limits is made by straight forward routine experimentation for a given system, and is easily done by the skilled man.
[0044] In an alternative embodiment it may be sufficient if only a fraction of the sample has entered the reactor. In this case the detection of signal onset is not used for triggering. Instead a certain time is determined empirically, namely the time it takes for the sample to just about reach the reactor after injection into the background flow. This time is then programmed into the control unit and used as a starting point for increaseded flow. This time can of course be selected such that different fractions of sample enter the reactor. It should be noted that if only a very minor fraction has entered when increaseded flow is initiated, the signal will be low; however, in most cases the entire sample will have reached the reactor by virtue of the void volume of the reactor being substantially larger than the sample volume.
[0045] It could also be possible to wait a short time, such as up to 5 seconds, after the sample completely has entered the reactor, i.e. after the detection by thermistor 32 , before increasing the flow. Thus, in fact there is a time interval during which increased flow can be performed. The actual set of parameters has to be found empirically for each individual system, and the skilled man will be able to find these parameters without inventive work.
[0046] The flow pulse at the higher flow rate is maintained until a preselected signal value from the reaction response has been recorded, e.g. a peak maximum, and at this point the flow will be decreased by a RETURN TO NORMAL FLOW command to the pump 10 , thereby stopping the additional flow of buffer solution. The duration of the pulse of increased flow rate may be 10-60 s, preferably 20-40 s.
[0047] Temperature fluctuations may be eliminated by thermostating the system, e.g. having the ER 26 immersed in a controlled temperature bath.
[0048] FIG. 4 illustrates the control algorithm in a simplified flow chart form.
[0049] When it is desired to make a measurement, the operator may select a INJECT command from a menu, or the computer may be programmed to issue the command at a preselected point in time. This command will set the valve such that the flow of sample (blood) is diverted into the buffer flow, for a time sufficient to inject the desired sample volume, i.e. 10 μl. Then, the valve is reset to normal mode, i.e. the blood is discharged as waste.
[0050] If the system parameters, such as configurations, flows etc. are well defined, then it is possible to preset the time T when increased flow is to be initiated. Thus, when the elapsed time t after injection of sample equals T, increasing is initiated by the computer.
[0051] Alternatively, the computer continuously registers the signal from the thermistor, and when a signal gradient, i.e. a temperature rise, of sufficient magnitude occurs, increasing the flow is initiated.
[0052] The increase in flow is performed by increasing the pump speed, by the computer issuing a INCREASE PUMP SPEED command to the interface, such the initial pump rate P 0 is increased by a factor corresponding to an increase of 5-100%, preferably by 10-50%, most preferably by 15-30%. Thus, the pump speed during increased flow (or pulse) mode is
P=P 0 +XP 0 .
[0053] After a time Δt when the reaction in the reactor is complete, the pump speed is reverted back to the initial value P 0 .
[0054] Then, control reverts to the computer for either a programmed new measurement at a preselected point in time, or an operator initiated measurement.
[0000] The Connector
[0055] In FIG. 2 a connector device for connecting to a patient, suitable for use in connection with the system according to the invention is illustrated.
[0056] The connector device, generally designated 100 , comprises a male part, generally designated 102 , and a female part, generally designated 104 .
[0057] The male part 102 is provided on the distal end of a catheter 106 that has been inserted in e.g. a blood vessel of a patient.
[0058] The female part 104 comprises a narrow tube 108 of e.g. steel, the inner diameter of which is larger than the inner diameter of the lumen 110 of the catheter 106 . The ratio between diameters is preferably 2-3:1. Furthermore, the steel tube 108 is milled or ground on its outer proximal end such that a sharp cutting edge 112 is formed, i.e. the outer surface is made slightly conical at the proximal end.
[0059] The tube 108 is inserted in and fixed centrally of a concentric socket structure 114 , forming said female part 104 . The socket 114 thus comprises a cylinder like element having a circular/cylindrical opening or bore 116 , the inner surface of which is slightly tapered, and in the center of which the tube 108 protrudes a fractional distance of the depth of said opening. Thus the cutting edge 112 of the tube 108 is located somewhere in the region between the bottom 118 of said opening 116 and its peripheral edge 120 . The tapering is such that the diameter at the bottom 118 is slightly smaller than the diameter at the peripheral edge 120 .
[0060] Similarly, the catheter is located centrally of a cylindrical member 122 forming the male part 102 , the outer diameter of which snugly fits inside the opening of the female part 104 . The end surface 124 of the catheter 106 is flush with the end surface 126 of the cylindrical member 122 . The tube 108 extends so much away from the bottom 118 of the female part that when the male and female parts are connected, the sharp edge 112 will penetrate the end surface of the catheter 106 .
[0061] The catheter 106 is made of a material that is enough resilient or soft, that when the male and female parts are connected, the cutting edge 112 sinks into the end surface 124 of the catheter 106 . Thereby a reliable and safe connection is provided in the transport of blood from the patient to the measuring system. Suitable materials for the catheter are e.g. soft PVC/silicone.
[0062] An example of a suitable locking device usable with the connector and having a male/female structure as outlined above is a Luer®-type lock.
[0063] As can be seen in the figure there is an abrupt change in the flow cross-section at the connection between catheter 106 and tube 108 . This is essential in the sense that it will prevent or alleviate clogging of the flow path. This principle is known.
[0064] By providing the direct contact connection between tube 108 and catheter 106 , as disclosed above, the large volume 116 is eliminated from the flow path. This is important in the sense that if the blood would have to pass such a large volume before entering the tube 108 , there would be enough time for the constituents of the blood to adhere to the inner surfaces of said volume 116 . In FIG. 3 a connector comprising an ordinary Luer-lock type coupling is shown. The male part 102 and the female part 104 are connected such as to form a dead space 119 . It is self evident that the flow rate will decrease drastically when the blood enters the large dead space 119 inside the coupling, thereby giving the blood constituents time to adhere to the inner surface of the connector and eventually clog the connector.
[0065] Of course it is equally conceivable to provide the catheter in the female part and the tube in the male part. However, the first embodiment is preferred since the sharp edge of the tube will be protected if arranged “inside” the female part, as shown.
[0066] Other types of couplings are of course conceivable, the important feature is the provision of a sharp edge on the tube, and a catheter having the necessary softness or resiliency that the edge will actually sink into the material when the parts are connected.
[0067] For example one could envisage some type of screw and nut connector, or a bayonet type coupling.
[0068] The invention will now be further illustrated by way of the following non-limiting Examples.
EXAMPLES
[0069] The following Examples were performed with the setup shown in FIG. 1 . The sensor was an enzyme reactor having dimensions 20 mm length×4 mm diameter.
[0070] The skilled man will easily be able to select suitable thermistors having the appropriate properties. One example of thermistor is obtained from Victory Eng. Inc.
[0071] The sample volume was 5 or 10 μl, and the background flow was 1 ml/min.
[0072] Signal values are given in Volts.
Example I (comparative)
[0073] In this example the flow was kept constant, and thus no increased flow was applied. The sample (blood) volume was 5 μl, and the base line signal was recorded before and after detection was made. Three consecutive runs were performed.
Signal/V
[0074]
Sample No.
Before det.
After det.
1
0.10
0.15
2
0.15
0.23
3
0.22
0.34
[0075] As is clearly demonstrated the baseline signal before detection increases from 0.10 to 0.22 V, and also the baseline signal after detection increases from 0.15 to 0.34 V.
Example II (comparative)
[0076] The experiment of Example I was repeated with a fresh sensor and new samples.
Sample No. Before det. After det. 4 0.14 0.38 5 0.35 0.63
[0077] Again the base line signals clearly are not reproducible between runs.
Example III (comparative)
[0078] In this example the flow was also kept constant but a sample prepared from a standard solution and glucose was introduced, and passed through the reactor.
Sample No. Before det. After det. 6 0.30 0.31 7 0.29 0.31
[0079] As can be seen, the base line signal is not affected.
Example IV (comparative)
[0080] The same conditions as in Example I, but the sample volume is increased to 10 μl.
Sample No. Before det. After det. 8 0.55 0.64 9 0.59 0.67 10 0.62 0.70
[0081] Again, the base line is not reproducible between runs.
Example V (According to the Invention)
[0082] In this example the sample volume was 1011. When the onset of sensor response was detected, the buffer flow was increased by 15% and maintained at that level for 20 seconds, when the response signal began to decrease again.
Sample No. Before det. After det. 11 0.23 0.22 12 0.23 0.22 13 0.23 0.22 14 0.22 0.22 15 0.21 0.22 16 0.20 0.22 17 0.21 0.22 18 0.21 0.21 19 0.23 0.21
[0083] As can be seen from the table, 9 consecutive runs were made and the base line returned reproducibly to the same level within the accuracy that measurements allow.
[0084] The system described herein is preferably designed as a “bed-side monitor”, i.e. a portable system for making around-the-clock surveillance of e.g. intensive care patients, or patients undergoing dialysis.
[0085] The control unit and other hardware components are thereby integrated in one single piece of equipment that is easily moved from one location to another.
[0086] Although the description has been made with reference to a system and method for analyzing analytes in blood, it is equally possible to use the inventive ideas for other types of complex biological/biochemical media, such as fermentation media, animal cell culture media.
[0087] For example it is suitable for analyzing ethanol or residual sugar in mash in brewing processes. It could also be used for analyzing various substances, e.g. insulin, amino acids or growth hormone in cell culture media.
[0088] It could also be used to analyze various components in milk or similar foodstuffs.
[0089] The skilled man could envisage numerous other applications of the basic principle of the invention, and implement them without inventive work.
[0090] 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.
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The invention comprises a method of regenerating a biosensor. It involves passing a background flow of fluid without reactive components through the flow passage. At a selected point in time a sample aliquot is injected into said background flow. At a point in time when a signal from said sensor is obtained the flow rate of the background fluid is increased. The invention also comprises a system for continuous monitoring of analytes in a biological fluid, the system having increased life by virtue of inherent regeneration of sensors employed. It comprises a biosensor ( 26, 30, 32 ), a sampling device ( 4 ) for providing a sample of said biological fluid, and means ( 10, 15, 18, 24 ) for passing a flow of a background fluid through said flow passage at selectable flow rates, means ( 20, 50, 55 ) for injecting said sample into said flow of background fluid, and means ( 50, 55 ) for increasing the flow rate of said combined flow. Means for achieving a washing action at the signal generating portion are provided.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application claims benefit of U.S. Provisional Patent Application Ser. No. 61/823,336, filed May 14, 2013 (APPM/17011USL), which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] Embodiments of the present invention generally relate to improving the threshold voltage in a thin film transistor (TFT).
[0004] 2. Description of the Related Art
[0005] Current interest in TFT arrays is particularly high because these devices may be used in liquid crystal active matrix displays (LCDs) of the kind often employed for computer and television flat panels. The LCDs may also contain light emitting diodes (LEDs), such as organic light emitting diodes (OLEDs) for back lighting. The LEDs and OLEDs require TFTs for addressing the activity of the displays.
[0006] The current driven through the TFTs (i.e., the on-current) is limited by the channel material (often referred to as the active material, semiconductor material or semiconductor active material) as well as the channel width and length. Additionally, the turn-on voltage is determined by the accumulation of the carrier in the channel area of the semiconductor layer which could change as the shift of the fixed charge in the semiconductor material or the charge trapping in interfaces and the threshold voltage shifts after bias temperature stress or current temperature stress. Current MO-TFTs, such as indium gallium zinc oxide (IGZO), zinc oxide (ZnO) and zinc oxynitride (ZnON) TFT devices, have interface problems which can include mobility problems and offset turn on voltages.
[0007] Therefore, there is a need in the art for better control of the threshold voltage of TFTs.
SUMMARY OF THE INVENTION
[0008] The present invention generally relates to controlling the threshold voltage and off-current of a TFT. In one embodiment, a semiconductor device can include a substrate comprising a surface with a thin film transistor formed thereon; a first passivation layer formed over the thin film transistor; a slot or trench formed in the first passivation layer; and a second passivation layer formed over the first passivation layer and within the trench.
[0009] In another embodiment, a semiconductor device can include a substrate comprising a surface with a thin film transistor formed thereon; a silicon nitride layer formed over the source electrode, the drain electrode and the semiconductor layer; one or more trenches formed through the silicon nitride layer; and a silicon oxide layer formed over the silicon nitride layer and within the one or more trenches. The thin film transistor can include a gate electrode disposed over a substrate; the gate dielectric layer disposed over the gate electrode; the semiconductor layer disposed over the gate dielectric layer; a source electrode disposed over the semiconductor layer; and a drain electrode disposed over the semiconductor layer.
[0010] In another embodiment, a method for forming a thin film transistor can include forming a source electrode and a drain electrode over a semiconductor layer that is formed over a gate dielectric layer and a gate electrode, a first portion of the semiconductor layer is exposed between the source electrode and the drain electrode; depositing a first passivation layer over the source electrode, the drain electrode and the exposed first portion of the semiconductor layer; forming at least one trench in the first passivation layer between the source and the drain to expose a second portion of the semiconductor layer; and depositing a second passivation layer on the first passivation layer and within the trench.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] So that the manner in which the above recited features of the present invention can be understood in detail, a more particular description of the invention, briefly summarized above, may be had by reference to embodiments, some of which are illustrated in the appended drawings. It is to be noted, however, that the appended drawings illustrate only typical embodiments of this invention and are therefore not to be considered limiting of its scope, for the invention may admit to other equally effective embodiments.
[0012] FIG. 1 is a cross-sectional schematic view of a PVD chamber according to one embodiment of the invention;
[0013] FIGS. 2A-2C are schematic cross-sectional views of a TFT at various stages of production; and
[0014] FIGS. 3A-3C depict TFT devices incorporating one or more slots or trenches according to one embodiment.
[0015] To facilitate understanding, identical reference numerals have been used, where possible, to designate identical elements that are common to the figures. It is contemplated that elements disclosed in one embodiment may be beneficially utilized on other embodiments without specific recitation.
DETAILED DESCRIPTION
[0016] The present invention generally relates to using trenches in the passivation layer to control the threshold voltage of a TFT. A TFT has a threshold voltage which is the voltage at the gate which is required for current to flow between the source and the drain. By forming one or more slots or trenches through the passivation layer, and then filling the slots or trenches with additional passivation material, the threshold voltage can be corrected such that current flow is better controlled by the gate when the gate is either on or off based on voltage received.
[0017] The invention is illustratively described below utilized in a processing system, such as a plasma enhanced chemical vapor deposition (PECVD) system available from AKT America, a division of Applied Materials, Inc., located in Santa Clara, Calif. However, it should be understood that the invention has utility in other system configurations, including those sold by other manufacturers.
[0018] FIG. 1 is a schematic, cross sectional view of an apparatus that may be used to perform the operations described herein. The apparatus includes a chamber 100 in which one or more films may be deposited onto a substrate 120 . The chamber 100 generally includes walls 102 , a bottom 104 and a showerhead 106 which define a process volume. A substrate support 118 is disposed within the process volume. The process volume is accessed through a slit valve opening 108 such that the substrate 120 may be transferred in and out of the chamber 100 . The substrate support 118 may be coupled to an actuator 116 to raise and lower the substrate support 118 . Lift pins 122 are moveably disposed through the substrate support 118 to move a substrate to and from the substrate receiving surface. The substrate support 118 may also include heating and/or cooling elements 124 to maintain the substrate support 118 at a desired temperature. The substrate support 118 can also include RF return straps 126 to provide an RF return path at the periphery of the substrate support 118 .
[0019] The showerhead 106 can be coupled to a backing plate 112 by a fastening mechanism 140 . The showerhead 106 may be coupled to the backing plate 112 by one or more fastening mechanisms 140 to help prevent sag and/or control the straightness/curvature of the showerhead 106 .
[0020] A gas source 132 can be coupled to the backing plate 112 to provide process gases through gas passages in the showerhead 106 to a processing area between the showerhead 106 and the substrate 120 . The gas source 132 can include a silicon-containing gas supply source, an oxygen containing gas supply source, and a nitrogen-containing gas supply source, among others. Typical process gases useable with one or more embodiments include silane (SiH 4 ), disilane, N 2 O, ammonia (NH 3 ), H 2 , N 2 or combinations thereof.
[0021] A vacuum pump 110 is coupled to the chamber 100 to control the process volume at a desired pressure. An RF source 128 can be coupled through a match network 150 to the backing plate 112 and/or to the showerhead 106 to provide an RF current to the showerhead 106 . The RF current creates an electric field between the showerhead 106 and the substrate support 118 so that a plasma may be generated from the gases between the showerhead 106 and the substrate support 118 .
[0022] A remote plasma source 130 , such as an inductively coupled remote plasma source 130 , may also be coupled between the gas source 132 and the backing plate 112 . Between processing substrates, a cleaning gas may be provided to the remote plasma source 130 so that a remote plasma is generated. The radicals from the remote plasma may be provided to chamber 100 to clean chamber 100 components. The cleaning gas may be further excited by the RF source 128 provided to the showerhead 106 .
[0023] The showerhead 106 may additionally be coupled to the backing plate 112 by showerhead suspension 134 . In one embodiment, the showerhead suspension 134 is a flexible metal skirt. The showerhead suspension 134 may have a lip 136 upon which the showerhead 106 may rest. The backing plate 112 may rest on an upper surface of a ledge 114 coupled with the chamber walls 102 to seal the chamber 100 .
[0024] FIGS. 2A-2C are schematic cross-sectional views of a TFT 200 at various stages of production. As shown in FIG. 2A , a gate electrode 204 is formed over a substrate 202 . Suitable materials that may be utilized for the substrate 202 include, but not limited to, silicon, germanium, silicon-germanium, soda lime glass, glass, semiconductor, plastic, steel or stainless steel substrates. Suitable materials that may be utilized for the gate electrode 204 include, but are not limited to, chromium, copper, aluminum, tantalum, titanium, molybdenum, and combinations thereof, or transparent conductive oxides (TCO) such as indium tin oxide (ITO) or fluorine doped zinc oxide (ZnO:F) which are commonly used as transparent electrodes. The gate electrode 204 may be deposited by suitable deposition techniques such as PVD, MOCVD, a spin-on process and printing processes. The gate electrode 204 may be patterned using an etching process.
[0025] Over the gate electrode 204 , a gate dielectric layer 206 may be deposited. Suitable materials that may be used for the gate dielectric layer 206 include silicon dioxide, silicon oxynitride, silicon nitride, aluminum oxide or combinations thereof. The gate dielectric layer 206 may be deposited by suitable deposition techniques including plasma enhanced chemical vapor deposition (PECVD).
[0026] A semiconductor layer 208 is then formed over the gate dielectric layer 206 as shown in FIG. 2B . Suitable materials that may be used for the semiconductor layer 208 include Indium Gallium Zinc Oxide (IGZO), Zinc Oxynitride (ZnON) ZnO x N y , SnO x N y , InO x N y , CdO x N y , GaO x N y , ZnSnO x N y , ZnInO x N y , ZnCdO x N y , ZnGaO x N y , SnInO x N y , SnCdO x N y , SnGaO x N y , InCdO x N y , InGaO x N y , CdGaO x N y , ZnSnInO x N y , ZnSnCdO x N y , ZnSnGaO x N y , ZnInCdO x N y , ZnInGaO x N y , ZnCdGaO x N y , SnInCdO x N y , SnInGaO x N y , SnCdGaO x N y , InCdGaO x N y , ZnSnInCdO x N y , ZnSnInGaO x N y , ZnInCdGaO x N y , and SnInCdGaO x N y . Each of the aforementioned semiconductor films may be doped by a dopant. The semiconductor layer 208 may be deposited by suitable deposition methods, such as PVD. In practice, the semiconductor layer 208 is oftentimes referred to as the channel layer, the active layer or the semiconductor active layer.
[0027] As shown in FIG. 2C , over the semiconductor layer 208 , the source electrode 210 and the drain electrode 212 are formed. The exposed portion of the semiconductor layer 208 between the source and drain electrodes 210 , 212 is referred to as the slot or trench 214 . Suitable materials for the source and drain electrodes 210 , 212 include chromium, copper, aluminum, tantalum, titanium, molybdenum, and combinations thereof, or TCOs mentioned above. The source and drain electrodes 210 , 212 may be formed by suitable deposition techniques, such as PVD followed by patterning through etching.
[0028] FIGS. 3A-3C depict TFT devices incorporating a slot according to one or more embodiments. In this depiction, the substrate 302 has a stack with one or more layers which are deposited and etched as described with reference to FIGS. 2A-2C , including a gate electrode 305 , a gate dielectric layer 306 , a semiconductor layer 308 , a source electrode 311 and a drain electrode 312 .
[0029] Depicted in FIG. 3A , a first passivation layer 318 is deposited over an exposed semiconductor material 316 , the source electrode 311 and the drain electrode 312 . In one embodiment, the first passivation layer 318 is a silicon oxide or silicon nitride layer, such as SiO x , SiN, SiON or combinations thereof. The first passivation layer 318 can be deposited to a thickness of from 20 Å to 3000 Å. The first passivation layer 318 can be deposited using CVD, PECVD, ALD or other deposition techniques known in the art. Deposition gases for depositing the first passivation layer 318 can include silanes, such as SiH 4 , N 2 O, O 2 , N 2 , an inert carrier gas, such as Ar, or combinations thereof. As depicted, the deposition of the first passivation layer 318 is substantially conformal across the surface of the exposed semiconductor material 316 , the source electrode 311 and drain electrode 312 . The first passivation layer 318 can have a low flat band voltage. In one embodiment, the flat band voltage of the first passivation layer 318 can be lower than −10 V. In another embodiment, the flat band voltage of the first passivation layer 318 can be approximately 0 V.
[0030] A trench 314 is then formed in the first passivation layer 318 between the source electrode 311 and the drain electrode 312 to expose the semiconductor layer 308 . The trench 314 can formed by patterning the first passivation layer 318 . The first passivation layer 318 can be patterned by forming either a photolithographic mask or a hard mask over the first passivation layer 318 and exposing the first passivation layer 318 to an etchant. The first passivation layer 318 may be patterned by exposing the exposed portions of the first passivation layer 318 to a wet etchant or to an etching plasma. In one embodiment, the etching plasma can comprise gases selected from SF 6 , O 2 , Cl 2 , or combinations thereof.
[0031] The trench 314 is generally a slot or trench which extends at least the length of the source electrode 311 and drain electrode 312 . In one embodiment, the source electrode 311 and the drain electrode 312 are both approximately 40 microns wide and the trench 314 extends approximately 50 microns to 60 microns. Thus, the ratio of the source/drain electrode width to the slot or trench length can be from 1:1 to 1:2, such as between 1:1 and 1:1.5. In this embodiment, the width of the slot or trench can be from about 1 micron to about 3 microns, such as about 2 microns. In further embodiments, the trench 314 can extend to multiple TFTs such that the trench is formed above the active channel region for each of the TFTs involved.
[0032] The trench 314 can be parallel to the edge of either the source electrode 311 or the drain electrode 312 . The trench 314 can be positioned at one or more locations in the portion of the first passivation layer 318 which is above the exposed semiconductor material 316 . Depicted here, the trench 314 is positioned approximately in the center of the first passivation layer 318 . However, the positioning of the trench 314 may be shifted within the region of the exposed semiconductor material 316 .
[0033] Once the trench 314 is etched, the exposed semiconductor material 316 can be treated with an activated gas. The activated gas can include oxygen, nitrogen or combinations thereof. The activated gas can be activated by plasma and delivered to the substrate to expose the exposed semiconductor material 316 , where the activated gas can be incorporated into the exposed portion of the exposed semiconductor material 316 . After the trench 314 is etched into the first passivation layer 318 and any treatment performed, a second passivation layer 319 is then formed over the surface of the first passivation layer 318 and the trench 314 . The second passivation layer 319 can be deposited generally in the same manner as the first passivation layer 318 . The second passivation layer 319 is composed of a separate passivation material from that of the first passivation layer 318 . In one example, the first passivation layer 318 is composed of silicon nitride and the second passivation layer 319 is composed of silicon oxide. In one or more embodiments, the material deposited in the trench 314 is the same material used to form the second passivation layer 319 . The first passivation layer 318 or the second passivation layer 319 may be deposited with or treated with either p-type dopants or n-type dopants.
[0034] Further, the first passivation layer 318 , the second passivation layer 319 or combinations thereof, can be composed of one or more sublayers, such that the first passivation layer 318 or the second passivation layer 319 are composed of a plurality of sublayers (not shown). The sublayers may be composed of silicon oxide or silicon nitride, such as SiO x , SiN, SiON or combinations thereof. The sublayers of the first passivation layer 318 or the second passivation layer 319 may have different compositions between them. The sublayers which interface between the first passivation layer 318 and the second passivation layer 319 should be of a different composition than one another. In one example, the first passivation layer 318 is composed of a single layer of SiN and the second passivation layer is composed of three layers, where the first layer is SiO, the second layer is SiON and the third layer is SiO. The first layer of the second passivation layer 319 forms the interface with the first passivation layer 318 . Further permutations are envisioned without further specific recitation.
[0035] FIG. 3B depicts a first passivation layer 338 deposited over the exposed semiconductor material 316 , the source electrode 311 and drain electrode 312 . The first passivation layer 338 can be substantially similar to the passivation layer 318 described with reference to FIG. 3A . In this embodiment, the passivation layer 338 has a trench 334 formed therein. The trench insert can be formed using the photomask/etch method described with reference to FIG. 3A . The trench 334 is wider in this embodiment and offset toward the drain electrode 312 . After the trench 334 is etched into the first passivation layer 338 , a second passivation layer 339 is then formed over the surface of the first passivation layer 338 and in the trench 334 . The second passivation layer 339 can be substantially similar to the second passivation layer described with reference to FIG. 3A .
[0036] FIG. 3C depicts a first passivation layer 358 deposited over the exposed semiconductor material 316 , the source electrode 311 and drain electrode 312 . The first passivation layer 358 can be substantially similar to the passivation layer 318 described with reference to FIG. 3A . In this embodiment, the passivation layer 358 has two trenches 354 formed therein. The trenches 354 are formed near both the source electrode 311 and the drain electrode 312 . After the trench 354 is etched into the first passivation layer 358 , a second passivation layer 359 is then formed over the surface of the first passivation layer 358 and in the trench 354 . The second passivation layer 359 can be substantially similar to the second passivation layer described with reference to FIG. 3A .
[0037] The trenches described above are believed to improve the threshold voltage (V th ) of the TFT. The V th is the value of the gate-source voltage when the conducting channel just begins to connect the source and drain contacts of the transistor, allowing significant current to flow. Though, optimally, this voltage would be zero, most modern TFTs do not achieve an optimal V th . Thus, many modern TFT can have a low steady current between the source electrode and the drain electrode, even when the gate is not receiving voltage. The trench is believed to shift the actual V th closer to the optimal V th through the creation of a second field which interferes with the first field.
[0038] While the foregoing is directed to embodiments of the present invention, other and further embodiments of the invention may be devised without departing from the basic scope thereof, and the scope thereof is determined by the claims that follow.
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Embodiments disclosed herein generally relate to thin film transistors with one or more trenches to control the threshold voltage and off-current and methods of making the same. In one embodiment, a semiconductor device can include a substrate comprising a surface with a thin film transistor formed thereon, a first passivation layer formed over the thin film transistor, a trench formed within the first passivation layer and a second passivation layer formed over the first passivation layer and within the trench.
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BACKGROUND OF THE INVENTION
FIELD OF THE INVENTION
The invention belongs to the mechanical arts and relates, more specifically, to a traveling-gear mechanism for a transport system of a cableway system. The mechanism is equipped with running rollers and with a coupling configuration.
Transport assemblies of prior art cableway systems are designed, on the one hand, with clamps, by means of which they can be clamped onto the haulage cable, and, on the other hand, with traveling-gear mechanisms, by means of which they can be moved along guide rails in the stations once the clamps have been opened. In such prior art cableway systems, the haulage cable is maintained at a running speed of approximately 8 m/sec. In the stations, the transport assembly is uncoupled from the haulage cable and moved through the station region along guide rails at such a speed that passengers can leave and/or board the corresponding transport device (e.g., gondola, cabin, lift chair, etc.).
It is known here for the running rollers to be produced from a metallic material. Such known running rollers, however, are disadvantageous because their movement along the guide rails, which are likewise produced from metal, causes very pronounced noise development. In order to keep the running noise to the lowest possible level, it is also known to produce the rollers of the running-gear mechanism from a plastic material. However, such running rollers have the disadvantage that they are at considerably greater risk of rupturing than is the case for running rollers produced from metal. If a running roller ruptures, this can cause serious disruption to operation. In particular, in the region where the transport assembly is coupled to the haulage cable, there is the risk of the haulage cable not being gripped by the clamps, as a result of which the transport assembly may crash downward as it leaves the station.
In order to eliminate this risk, it is known to provide additional guide rails, which are intended to ensure that the haulage cable is gripped by the clamps even if a running roller ruptures. These additional guide rails, however, do not meet the current requirements because they result in a further high level of design-related outlay and also because they do not ensure proper functioning of the clamps.
SUMMARY OF THE INVENTION
The object of the present invention is to provide a traveling-gear mechanism which overcomes the above-noted deficiencies and disadvantages of the prior art devices and methods of this general kind, and which clearly avoid the disadvantages of the prior art traveling-gear mechanisms.
With the above and other objects in view there is provided, in accordance with the invention, a running-gear mechanism for a transport assembly of a cableway system, comprising: running rollers configured to run in a guide rail, a coupling assembly for coupling the running-gear mechanism to a cable, and at least one downwardly projecting continuation disposed in a vicinity of the running rollers and configured to project into the guide rail.
In other words, the objects of the invention are achieved by providing, in the region of the running rollers, at least one downwardly projecting continuation which projects into the guide rails. In the case where a running roller ruptures, the continuation projecting into the guide rail assumes the function of a runner which slides in the guide rail, i.e., the projection “catches” the assembly, and then provides for the necessary emergency running properties during the coupling operation of the clamps.
In accordance with an added feature of the invention, the assembly is formed with a load-bearing member carrying the running rollers. In that case, the at least one continuation projects from the load-bearing member.
In accordance with an additional feature of the invention, the at least one continuation is disposed in a plane defined by the running rollers.
In accordance with another feature of the invention, there are provided a plurality of rollers. The at least one continuation is formed as two continuations disposed outside the two outer running rollers.
In accordance with again another feature of the invention, the two continuations are disposed to butt closely against the running rollers, and with a cross section decreasing in a direction away from the running rollers.
In accordance with a concomitant feature of the invention, the running rollers define a running surface at a given level, and the at least one continuation has a length such that a free end thereof terminates slightly above the given level.
In other words, there are preferably provided two continuations which are located outside the two outer running rollers of the traveling-gear mechanism. In this case, the two continuations may be arranged to butt closely against the running rollers, and they have a cross section which decreases in the direction away from the running rollers. In addition, the at least one continuation is preferably of such a length that its free end terminates slightly above the running surface of the running rollers.
Other features which are considered as characteristic for the invention are set forth in the appended claims.
Although the invention is illustrated and described herein as embodied in a traveling-gear mechanism for the transport assembly of a cableway system, 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.
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
FIG. 1 is a side-elevational view of the traveling-gear mechanism of a transport assembly of a cableway system;
FIG. 1 a is a sectional view of the traveling-gear mechanism taken along the line A—A in FIG. 1;
FIG. 2 is a side elevational view of a load-bearing member for the running rollers of the traveling-gear mechanism according to FIG. 1;
FIG. 2 a is a plan view of the load-bearing member; and
FIG. 2 b is an end view of the load-bearing member.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring now to the figures of the drawing in detail and first, particularly, to FIG. 1 thereof, there is seen a traveling-gear mechanism for a transport assembly, such as a cabin or a chair, of a cableway system. The traveling-gear mechanism comprises a load-bearing member 1 for two running rollers 2 . Additionally provided on the traveling-gear mechanism are a clamping mechanism 3 and a control mechanism 4 which interacts therewith. Since these arrangements are known from the prior art, they will not be explained in any more detail. Reference may be had, for example, to European patent EP 621 163 B1 which describes a clamping and control mechanism of this general type. The running rollers 2 , in the stations, are assigned guide rails 20 , along which the transport assembly which have been uncoupled from the haulage cable are moved through the stations at such a speed that passengers can board and/or leave them.
The load-bearing member 1 for the running rollers 2 is designed with downwardly projecting continuations 5 which are located laterally outside the two running rollers 2 . The continuations are arranged directly alongside the running rollers 2 and are of such a length that they terminate just slightly above the running surface of the guide rail 20 .
The task of these continuations 5 is, in the case where a running roller 2 ruptures, to act as a runner in the guide rail 20 . When the roller 2 ruptures, the continuation 5 assumes the function of the ruptured running roller so as to ensure the emergency running properties which are necessary for the coupling operation.
In order to fulfil this function, the continuations 5 have to project as far as possible in the guide rails 20 . This ensures that, in the case of a running roller rupturing, the running-gear mechanism is retained in virtually the same vertical position as in the case of a fully functional running roller 2 . In addition, the continuations 5 have to be of a width which is approximately equal to the width of the running rollers 2 , in order thus also to ensure guidance in the necessary lateral position. Since, however, it is also necessary here to ensure the necessary ability of the running-gear mechanism to negotiate curves, the continuations 5 are of approximately triangular design in horizontal cross section. In this respect, reference is had to the illustration of FIG. 1 a.
The load-bearing member 1 , which is designed with continuations 5 and is intended for the running rollers 2 , will be explained in more detail with reference to FIGS. 2, 2 a and 2 b . The load-bearing member 1 , which is configured as an elongate component made of sheet steel, has two plates 11 which are formed with bores 12 into which it is possible to insert bolts for the running rollers 2 . In addition, in the plane of the running rollers 2 , it is designed with the two obliquely downwardly projecting continuations 5 , which project into the guide rails. In the case where the associated running roller ruptures, the continuations 5 act as runners that slide in the guide rails. As a result of this the necessary emergency running properties are achieved. The load-bearing member 1 is also designed with bores 13 , which serve for fastening the clamping assembly on the load-bearing member. In addition, it is formed with bores 14 , which serve for fastening the friction surface against which the conveying wheels come into abutment.
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A running-gear mechanism for the transport assembly of a cableway system has running rollers that roll in guide rails while the coupling assembly is uncoupled from the haulage cable. In the region of the running rollers there is provided at least one downwardly projecting continuation which projects into the guide rails.
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FIELD OF THE INVENTION
This invention relates to a cylinder lock which can be controlled by electric signals. To explain further, in detail, the locking and release of the rotating inner cam in relation to the outer barrel can be controlled by an electric signal.
BACKGROUND OF THE INVENTION
Up to now, a so called electric or electronic lock controlled by an electric signal involved a locking/unlocking action initiated by an electric motor or a solenoid. But, these actuators require power from a few watts to over ten watts and an actuating time of over 100 milliseconds therefore electric energy of over one Joule is necessary to institute the locking/unlocking action.
Up to now, the construction of the electronic lock has been such that the locking bolt has been directly attached to the locking actuator and also a large lock body has been required to install a large actuator. Also, power consumption is very high. Therefore, there is a limit for fitting to the door and maintenance is troublesome.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a small sized, low power consumption electronic lock.
Another object of this invention is to provide an electronic cylinder for a lock where the condition of release or not between the inner cam and the outer barrel can be controlled by judging whether the electric signal received from the electronic key is correct or false.
Still another object of the present invention is to provide an electronic cylinder that cannot be picked by the use of a false mechanical key or any other mechanical means. The cylinder for locks contains an outer barrel and an inner cam with a keyhole such that when the means of operation is inserted in the said keyhole in the said inner cam, the said inner cam can rotate inside the said outer barrel.
According to the present invention in a cylinder for locks containing an outer barrel and an inner cam with a keyhole such that a rotating operation of said inner cam can be carried out inside said outer barrel by means of an operating means which is to be inserted in the said keyhole in the said inner cam, said cylinder comprises an arm component which is installed in an inner space of said outer barrel by a supporting member and supported such as to allow free see-saw or pivot action, a through hole defined in said outer barrel, an engaging hole placed in the said inner cam such that when said inner cam and said outer barrel are in the correct position both said through hole and said engaging hole are in alignment, a pin component mounted on said arm component, said pin component being for prohibiting relative movement of said inner cam to said outer barrel when said pin component is inserted into said engaging hole through said through hole a spring means for urging said arm component in a direction wherein said pin component is withdrawn from said engaging hole, a driving mechanism for driving said pin component into the said engaging hole overcoming the opposing force provided by the said spring means in response to a prescribed operation of said operating means and, a holding mechanism for holding a condition where said pin component is engaged into said engaging hole without consuming electric power when said pin component enters a predetermined state with respect to the engaging hole, said holding mechanism being capable of releasing said pin component from the held position when an electric signal is received.
The binding and release of the inner cam can be accomplished by the interaction of the pin component and the engaging hole. The pin is required to move 2-4 mm and large power is needed for the operation of an electro-magnetic device which has a 2-4 mm gap. Because the ampere turns required to get the necessary magnetic flux is proportional to the gap length and the required electric power is proportional to the square of the ampere turns the following is apparent.
The cylinder of this invention includes a self-holding electromagnetic device. To close the air gap of the holding device the means of operation is withdrawn from the keyhole situated in the inner cam by using human power. The release of the holding device from the held position requires the receipt of an electric signal from an external source.
When the holding device is in the held position the air gap is negligible and because of the aforementioned properties of the electro-magnetic device an extremely small amount of electric power is needed to move the device from the held position. Also, the operating time is extremely small and the physical construction of the electro-magnetic device is very small.
When the correct key is inserted into the cylinder lock an electric signal is received from the key and in response to the receipt of this signal the pin is withdrawn from the engaging hole by a spring means once the electro magnetic device has been moved from the held position thus allowing the rotation of the inner cam. The inner cam then be rotated by turning the key causing the retraction of the lock's locking bolt. The withdrawal of the pin is initiated by the use of electric power. This power is extremely small.
In order to return the holding device from the held open position either the inner cam is rotated or the key is withdrawn from the keyhole. This process does not use any electric power allowing substantial saving of power to be made. The withdrawal of the pin is therefore done using a combination of a spring means and an electric force which requires very little power.
In conjunction, the insertion of the pin into the engaging hole is done entirely by human force and a spring means resulting in zero power consumption. Because of the extremely low power consumption a small type battery can be used to supply power. This battery can either be installed in the cylinder or it can be installed in the key to supply power to the cylinder. If the battery is installed in the key it means an electronic cylinder lock can be produced that does not contain a power source, resulting in extremely low maintenance requirements. The invention will be better understood and the other objects and advantages thereof will be more apparent from the following detailed description of preferred embodiments with reference to the accompanying drawings.
BRIEF EXPLANATION OF THE DRAWINGS
FIG. 1 is a sectional elevation to show the actual operation of an electrically controlled cylinder for locks under this invention.
FIG. 2 is a front elevation of an electrically controlled cylinder as shown in FIG. 1.
FIG. 3 is a sectional elevation of a cylinder to show that relative revolutionary motion of the inner cam and the outer barrel is possible.
FIG. 4 is a sectional elevation of FIG. 1 along A--A line.
FIG. 5 is a sectional elevation of FIG. 1 along B--B line.
FIG. 6 is a sectional elevation to show another example of the actual operation of an electrically controlled cylinder for locks.
FIG. 7 is a sectional elevation of inner cam along C--C line taken from FIG. 6.
FIG. 8 is a sectional elevation to show an additional example of actual operation.
FIGS. 9A and 9B are enlarged and detailed pictures of holding type electro magnetic device as shown in FIG. 8.
FIG. 10 is a block diagram of the control unit shown in FIG. 1.
FIG. 11 is a perspective view of a special mechanics of FIG. 1.
DESCRIPTION OF PREFERRED EMBODIMENTS
The cylinder 1 according to this invention as shown in FIG. 1 and FIG. 2 is equipped with outer barrel 2 and inner cam 3 which can freely revolve inside a space 2a. Inner cam 3 has a key-hole 5 wherein an electronic key 4 is to be inserted. By twisting the electronic key 4, inner cam 3 can revolve inside a space 2a to a pre-determined angle. However, inner cam 3 is incorporated into outer barrel 2 by a commonly used method so that it does not move towards the Y-axis inside the space 2a. A plate protuberance 6 is attached to one end of inner cam 3, and when the inner cam 3 revolves, its revolutionary motion is transmitted through this protuberance 6 to a bolt inside a lock box which is not shown in FIG. 1 and FIG. 2.
Special mechanics 10 are installed in the space 2b inside an outer barrel 2 in order to work the binding and release of the relative revolutionary motion between the outer barrel 2 and the inner cam 3.
The special mechanics 10 is shown in FIG. 11. The special mechanics 10 has an L-shaped supporting material 11 firmly fixed by some method to the inside wall of the space 2b. At the free end 11b of the vertical arm 11a of the L-shape supporting material 11, a long plate shaped spring arm is attached slightly off its center by means of a movable iron 22 such that it can move with see-saw or pivotal action.
On the barrel 2, a hole 2c is opened to hold the tip 13a of pin 13, and also in the inner cam there is a hole 3a in order to insert the tip 13a through the hole 2c.
This engaging hole 3a, as shown in picture 4, is oriented to form a line with the hole 2c in order to hold the outer barrel 2 and the inner cam 3 in their prescribed relative positions. When this is completed, the relative revolutionary motion between the inner cam 3 and the outer barrel 2 becomes impossible. The inner cam 3 is now in the locked state.
When the hole 2c and the engaging hole 3a are in perfect alignment, the electronic key 4 can be freely inserted or withdrawn from the keyhole 5 situated in the inner cam 3. The motion of the tip 13a of the pin 13 into the engaging hole 3a is governed by the motion of the electronic key 4 in the keyhole 5. For this purpose the base end of rod 14 is firmly fixed by some method to the other end of the movable arm 12. The tip 14a of the rod 14 is directed towards the inner cam 3 and this tip 14a is inserted into the keyhole 5 by passing the tip 14a through the holes 2a and 3b inside the outer barrel 2 and the inner cam 3 respectively so that the tip 14a comes into contact with the base of the concave groove 4a situated in the key 4 which is now situated in the keyhole 5.
Numeral reference 15 shows a sleeve which covers the tip 14a of rod 14 in order to protect against picking. The sleeve 15 is constantly pressed in contact with the tip 14a of the rod 14 by a plate spring 16. Therefore, normally the sleeve 15 will move in conjunction with the rod 14. There is a contracting coil spring 13 between the movable arm 12 and the inner wall of the space 26 and by the contracting power of the spring 17 the arm 12 is energized so that pin 13 is withdrawn from the engaging hole 3a. This situation is indicated in picture 1, where the tip 14a of the rod 14 together with the sleeve 15 is fitted in the concave groove 4a of the electronic key 4. As a result of this, the inner cam 3 can rotate freely in the space 2a by twisting the electronic key 4. The inner cam 3 is now in the unlocked state.
As you can see from FIG. 5, the hole 3b inside the inner cam 3 extends along the circumference for 180 degrees forming a groove in the inner cam 3. According to FIG. 1, the electronic key 4 can be used to either lock or unlock the inner cam 3 depending on your preference.
As shown in FIG. 1, when the electronic key 4 is withdrawn from the keyhole 5, the rod 14 is forced out of the concave groove 4a causing the movable arm 12 to pivot and forcing the tip 13a of pin 13 into the engaging hole 3a thus locking the inner cam 3. There is an electro-magnetic holding device 18 which is used to hold the arm 12 in the locked state and is also used to release the arm 12 in response to the receipt of an electric signal when requested. This consumes very little electric power.
The electro-magnetic holding device 18 is made of of a permanent magnet self-holding electro-magnet 21 which consists of a permanent magnet 19, a core 19a around which is wound a solenoid coil 20 and a steel plate 22 which is fixed to the movable arm 12. The steel plate 22 is oriented such that it faces the core 19a (see FIG. 11).
When the rod 14 is forced out of the groove 4a, in response to the operation of the key 4, the gap between the plate 22 and the core 19a becomes negligible. The steel plate 22 is then attracted and held by the permanent magnet 19 causing the inner cam 3 to become held in the locked state.
Then, using the control unit (c/u) 30 with its build-in power source an exciting current is supplied to the solenoid coil 20 in such a way so as to reduce the effective magnetic flux of the permanent magnet 19. Due to this the attracting force of the permanent magnet self-holding electro-magnet 21 becomes weaker than the opposing force of the coil spring 17 which causes the arm 12 to pivot lifting the tip 13a of pin 13 out of the engaging hole 3a. This means the inner cam 3 is now free to rotate.
The release current to be fed to the permanent magnet self-holding electro-magnet 21 is supplied by the control unit 30 with its built in power source, as shown in the picture, or it can be supplied through the manual operation of an on/off switch from an outside power source.
In the example as shown, the electronic key 4, as in FIG. 1 contains the following parts:
a sensor 41 to detect whether the electronic key 4 is inserted in the keyhole 5,
a signal generator 42 to generate a predetermined code signal in response to the output signal of sensor 41,
a coil 43 which is used to transmit the signal from the signal generator 42 to the control unit 30,
a battery 44 which is built into the electronic key 4 to supply the power necessary for this operation.
On the other hand, the control unit 30, as shown in FIG. 10, contains a coil 31 which is used to receive the signal transmitted from coil 43. It also contains decoding circuitry 32 to determine if the received code is correct or not. If the code is correct the exiting current will be supplied to the solenoid 20. All the power necessary for this operation is supplied by the battery 33. Hence, it is obvious that the material making up the principal part of the electronic key 4 must be hard and robust, such as hard plastic, and into which the necessary electronic components, battery etc. can be moulded.
Hereunder, the operation of the electrically controlled cylinder will be described.
FIG. 1 shows the case where pin 13 is inserted in the engaging hole 3a such that the inner cam 3 cannot rotate. In this state the movable arm 22 is attracted by the magnetic flux of the permanent magnet 19 and held in this position without consuming power. While in this state if the electronic key 4 is inserted fully into the keyhole 5 the key 4 transmits a code signal which is received by the control unit 30 and processed. Only if the processed code signal is correct will an exciting current be fed to the solenoid 20.
This current flows in a direction such as to diminish the flux of the permanent magnet 19. Therefore the flux holding the armature 22 is diminished and the force of spring 17 becomes larger than that of the electro magnet 21, this forces armature 22 into the up position due to the pulling force of spring 17. This also causes pin 13 to be raised. The inner cam 3 is now free to rotate and the lock/unlock condition can be achieved. Pin 13 must move a distance of between 2-4 mm for the unlock state to be reached, and the contracting force of spring 17 is sufficient to do this without consuming electric power. The electric power needed to reduce the magnetic flux of the permanent magnet 19, based on the data taken from the test sample, was 0.10 watts. This is based on a holding force of the holding device of 50 grams and a spring force of 25 grams for the spring 17. 5 mS was found to be sufficient time for supplying power in order for the unlocking action to take place. This means there is an energy consumption of: 0.1 watts×5 mS=0.5 milliJoules. FIG. 3 shows the unlocked state of the cylinder where the pin 13 is in the raised position.
In addition, when pin 13 is in the raised position the rod 14 is, in the reverse manner, forced down into the concave groove 49 contained in the electronic key 4. In this state the inner cam 3 is free to rotate, so that when the electronic key 4 is twisted manually it forces the rod 14 to move upwards through the hole 2a according to FIG. 4. Also, when the inner cam 3 is twisted the lock body connecting plate 6 also rotates. Thus the bolt in the lock body can be retracted and extended by the rotation of the inner cam. This is not shown in FIG. 3. The locking and unlocking directions can be predetermined by specifying the direction of rotation of the inner cam 3. This design for the cylinder lock has now been used for a long time and is hence in the public domain.
When the locking or unlocking action is complete the inner cam 3 returns to its initial position and only in this position can the electronic key 4 be withdrawn from the keyhole 5. This method is also in the public domain as it has been used for many years. The withdrawal method is shown in FIG. 2.
In this state when the electronic key 4 is withdrawn the rod 14 is pushed upwards as it slides upward along the slope of the concave groove 4a. This causes the arm 12 to pivot forcing the plate 22 to come into contact with and be held by the permanent magnet 19. The amount of movement of the rod 14 must be sufficient to bring the plate 22 into contact with the permanent magnet 19. Therefore the concave groove 4a in the electronic key 4 must be designed with enough leeway to ensure that the operation is always performed. Depending on this leeway an excess movement may occur in the arm 12 therefore this arm is designed to flex slightly to overcome this problem. In continuation, as the arm 12 moves upward the plate 22 moves downward into the engaging hole 3a. This action prevents any relative motion of the inner cam 3 and the outer barrel 2 as they are now locked by the pin 13. In this way the cylinder can be relocked and held in this state without using any electric power.
From the previously mentioned test sample data the power needed to release the plate 22 from the held position was 0.1 watts. However, when a gap of 0.8 mm exists between the plate 22 and the core 19a of the electromagnetic device 21 a power of 7 watts and an operating time of 12 milliseconds is required in order to close the gap. This means the amount of energy required is:
7 W×12 mS=84 milliJoules.
In this way, this invention can save considerable amounts of energy.
The above explanation applies to the example outlined in FIG. 1. When the electronic key 4 is withdrawn with withdrawing power is used to return the plate 22 to the held position of the electromagnetic holding device and the inner cam 3 becomes impossible to rotate. This in turn means the lock cannot be opened.
In addition, based on the example in FIG. 1, the sleeve 15 which covers the tip of the rod 14 and is held by the plate spring 16 is used to prevent against so-called picking. When the rod 14 is in the raised position the sleeve 15 is used so that no external means can be introduced into the hole 2a to interfere with the rod 14 as there is no direct physical connection between the sleeve 15 and the rod 14.
FIG. 6 is another represenation of this invention. The method outlined in FIG. 6 is such that when the inner cam 3 is rotated the rod 14 is pushed upwards causing the plate 22 to become held by the holding device. In the cylinder outlined in FIG. 6, denoted 1', the hole 2d of the outer barrel 2 corresponds to the groove 3c whose shape is outlined in FIG. 7. In FIG. 7 when the rod 14 is in the down position and the inner cam 3 is rotated the rod 14 is pushed upward causing the plate 22 to be attracted to and held by the magnetic holding device. When the pin 13 and the engaging hole 3a are not perfectly aligned the pin 13 cannot be inserted into the engaging hole 3a. In this case the plate spring 9 bends applying a downward force onto the pin 13. Under this force pin 13 slides along the outer surface of the inner cam 3 as it is rotated. When the inner cam 3 has been returned to the position where the key 4 can be withdrawn and the key 4 is then withdrawn the pin 13 is then pushed into the engaging hole 3a. The inner cam 3 is now in the locked state. On top of this as you can see from FIG. 6, the concave groove 4a in the key 4 is not necessary for this operation.
The apparatus shown in FIG. 8 is a mechanical type holding device. With the previously mentioned electromagnetic device it was stated that the operating power increases in proportion with the square of the length of the air gap between the steel plate armature 22 and the core of the electromagnet 19a. Therefore if an electromagnet where the air gap is small is used only a small operating power is necessary in order to move the pin 13.
The apparatus outlined in FIG. 8 differs from that outlined in FIG. 1 in the method of the construction of the holding device 18. In FIG. 8 the holding device is a mechanical arrangement whereas in FIG. 1 the holding device is a permanent magnet electromagnetic holding device.
The holding device 50 sohwn in FIG. 8, as shown in detail in FIGS. 9a and 9b consists of an electromagnet 51 with an exciting coil, an armature 52 such that it can be hooked to the arm 12 which is attached to the pin 13 when the pin 13 is in the down i.e. locked position and a spring 54 which is fixed between the electromagnet 51 and the arm 52 so that it applies a force to the arm 52 in a direction such as to move the arm 52 towards the pin 13.
The case shown in FIG. 9a is that where the electromagnetic device 50 is not energized. As the key 4 is withdrawn from the keyhole 5 the pin 13 is forced downwards with the point of the hook 53 sliding along the side of the pin 13 in a direction opposing the direction of the spring force 54. Once the arm 12 has completely passed the tip of the hook 53 the spring 54 applies a force such that the hook 53 is once again brought into contact with the side of the pin 13 such that the pin 13 cannot return from this position. The tip 13a of pin 13 is now inserted into the engaging hole 3a and is held in this locked state. Therefore the inner cam 3 cannot be rotated and the main lock body cannot be operated.
The case shown in FIG. 9b is that where the electromagnetic device is energized. When electric current is applied to the electromagnetic device 50 the arm 52 is attracted toward the core releasing the hook 53 holding the arm 12. The arm 12 is now free to move and under the force supplied by the spring 17 the arm 12 moves in an upward direction causing the pin 13 to be withdrawn from the engaging hole 3a. The inner cam 3 is now free to rotate. The main lock body connected to the plate 6 can now be operated by twisting the key 4.
According to the above explanation contained in FIGS. 8-9b the amount of movement of the pin 13 is 2-4 mm however, the amount of movement of the hook 53 is only 0.2-0.5 mm therefore the amount of electric power required to operate the electromagnetic device is small.
To return the pin 13 from the case outlined in FIG. 9b to that outlined in FIG. 9a the electronic key 4 is withdrawn from the keyhole 5 in the same way as was applied to the case in FIG. 1 where human power only was used. In this way absolutely no electric power is consumed. Therefore, in the case outlined above, as was the case for that explained in FIG. 1, the power consumption of the complete invention is extremely small.
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In a cylinder for locks having an outer barrel and an inner cam with a keyhole. In order to lock the movement of the inner cam, a pin is provided in the outer barrel and the pin is engaged into a hole defined in the inner cam to lock the inner cam. The pin is urged by a spring so as to eject the pin from the hole and the pin is inserted into the hole by a driving mechanism utilizing a manual force. The engaging state of the pin with respect to the hole is held by a hold mechanism without any electric power consumption. The hold mechanism is responsive to an electric signal to release the engaging state between the pin and the hole.
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FIELD OF INVENTION
[0001] The present invention relates, generally, to a process for the production of fuel grade dimethyl ether (DME) from methanol dehydration via catalytic distillation. The methanol is produced from syngas in a methanol synthesis loop and this syngas is produced from natural gas in a steam reformer using either a pressurized burner or an atmospheric pressure burner.
BACKGROUND OF INVENTION
[0002] Dimethyl ether (DME) is rapidly being recognized as the optimum energy vector for the 21st century. Its high oxygen content and absence of carbon to carbon bonds eliminate soot and particulates in the post combustion environment. The application of DME is especially logical in countries that are poor in oil and gas resources. DME is much more environmentally friendly than conventional hydrocarbon fuels.
[0003] DME's overall physical properties are similar to those of LPG. DME liquefies at 59 psia (6.1 bar) or −13° F. (−25° C.). Its vapor pressure at 122° F. (50° C.) is 170 psig (12.7 bar), while that of propane is 250 psig (18.3 bar). Since DME can readily exist in a liquid form, it is easily transportable in terms of international trade.
The DME end product, when it is utilized, will be 100% clean. DME can be used as a one-to-one replacement as a fuel for diesel engines. As a diesel fuel replacement, DME is 100% clean in terms of sulfur, 100% clean in terms of soot or particulates, and much cleaner than conventional fuels in terms of NO X and CO 2 emissions. DME is decomposed in a troposphere in less than a day; it does not cause ozone layer depletion.
[0008] DME can be produced from syngas (CO and H 2 ) generated by natural gas reforming directly as described by I K Hyun Kim et al. in REF. 1:
[0000] 3CO+3H 2 →CH 3 OCH 3 +CO 2 ΔH 270° C.=− 258.73 KJ/mol (1)
[0000] Or from methanol synthesis and then methanol dehydration:
[0000] 2CO+4H 2 →2CH 3 OH ΔH 270° C. =−201.84 KJ/mol (2)
[0000] 2CH 3 OH→CH 3 OCH 3 +H 2 O ΔH 270° C. =−17.35 KJ/mol (3)
[0009] In the direct DME synthesis process when natural gas is used as the carbonaceous feedstock, it requires a H 2 to CO molar ratio to be close to 1.0 (EQ. 1) in the DME synthesis loop feed gas. Therefore, a huge amount of CO 2 is fed to the reformer to manipulate this ratio. The majority of added CO 2 then has to be removed by a solvent wash such as cold methanol (Rectisol™), or chilled Selexol™ physical solvent to avoid CO 2 build up in the DME synthesis loop. In addition, the CO 2 produced by EQ. 1 will also have to be removed at cryogenic condition, i.e. −40° F. (−40° C.) by the produced DME and some methanol (REF. 1). The DME and methanol produced are used here as the CO 2 absorption solvent. While the DME synthesis temperatures are 536 to 572° F. (260 to 300° C.), this causes a huge energy loss in heating and cooling. Because of these reasons, we abandon the natural gas to DME synthesis direct process in this invention.
[0010] In the indirect DME synthesis process, methanol will have to be synthesized first (EQ. 2) and then dehydrates the methanol synthesized to produce DME (EQ. 3). There are several methanol synthesis processes available. The major differences among these processes are in the methanol synthesis loop designs used to remove the heat generated by the highly exothermic methanol synthesis reactions. The method currently used by these processes is to increase the H 2 to CO molar ratio of the feed gas to the methanol synthesis loop far beyond the stoichiometric ratio in order to remove the exothermic heat. For instance, Imperial Chemical Industries (ICI) methanol synthesis process (REF. 2) uses a H 2 /CO molar ratio in the feed gas to the methanol synthesis loop of 7.97; Johnson Matthey (REF. 3), 16.62; Exxon Mobil (REF. 4), 6.70; TEC (REF. 6) 10.53; and UNITEL (REF. 7), 7.05. In methanol synthesis, the feed gas to the methanol synthesis loop is characterized by the stoichiometric ratio (H 2 —CO 2 )/(CO+CO 2 ), often referred to as the module M. A module of 2.05 defines an ideal stoichiometric synthesis gas for formation of methanol. These high values of the H 2 /CO molar ratio used by these methanol synthesis processes yield high module numbers also (Table 1).
[0000]
TABLE 1
FEED SYNGAS COMPARISON WITH LITERATURE DATA IN METHANOL SYNTHESIS
Present
Invention
Exxon
Johnson
Feed Gas
1
UNITEL
ICI
Mobil
TEC
Matthey
Phase
Vapor
Vapor
Vapor
Vapor
Vapor
Vapor
Temperature, ° C. (° F.)
205 (401)
110 (230)
80 (176)
77 (170)
240 (464)
230 (446)
Pressure, bar (psig)
71 (1,015)
82 (1,175)
84 (1,204)
85 (1,218)
100 (1,436)
85 (1,218)
Feed Gas Comp., mol %
CH 4
10.68
5.74
9.33
12.05
1.35*
10.10
CO
15.75
9.08
8.70
10.31
7.90
4.89
CO 2
9.50
10.60
10.45
4.14
5.80
3.27
H 2
61.16
64.00
69.37
69.03
83.20
81.24
H 2 O
0.22
0.24
0.11
0.10
0.10
0.12
N 2
2.27
9.76
1.66
3.84
1.35*
0.00
CH 4 O
0.42
0.58
0.38
0.53
0.30
0.38
TOTAL
100.00
100.00
100.00
100.00
100.00
100.00
Feed Gas H 2 to CO
3.88
7.05
7.97
6.70
10.53
16.62
Molar Ratio
Feed Gas Module
2.05
2.71
3.08
4.49
5.65
9.56
Number
CO 2 in Feed Gas, wt %
33.85
37.67
43.65
19.59
35.69
23.64
Methanol Synthesis
12.65
12.56
9.52
8.83
—
5.10
Loop Recycle Gas MW
Methanol Synthesis
1.24
2.35
1.99
4.00
—
3.00
Loop Recycle to Make-
up Gas Molar Ratio
Methanol Synthesis
29.65
15.00
5.64
1.48
—
8.85
Loop Recycle Purge, %
Internal Reactor Cooling
No
Yes
Yes
No
Yes
Yes
H 2 Recovery from Purge
No
No
Yes
No
—
No
of Methanol Synthesis
Loop
Recovery from H 2
Yes
Yes
Yes
No
—
No
Membrane Recycle Gas
*Assume equal amount of CH 4 and N 2 in the gas mixture.
[0011] The drawback of these high module numbers is that they dilute the reactants which reduce the syngas conversion efficiency for methanol synthesis and meanwhile cause a tremendous increase in the energy required by the recycle stream compressor, in addition larger methanol synthesis reactor(s) and piping are also required. The details of this drawback will be further illustrated in Example 3.
[0012] It has now been found that the above drawback can be avoided by (i) purging recycle gas of the methanol synthesis loop to the H 2 membrane; (ii) recovering a H 2 rich stream from the H 2 membrane; (iii) purging recycle gas B ( FIG. 1A ) to the steam reformer HP burner; (iv) feeding both remaining recycle gas B and natural gas to the saturator; (v) manipulating these two purge rates to obtain 2.05 module number for the methanol synthesis feed gas and meanwhile also provide appropriate remaining recycle gas B flow to evaporate enough steam in the saturator for the downstream steam reforming reactions.
SUMMARY OF THE INVENTION
[0013] It is the object of the present invention to provide a process of economically and efficiently producing DME, which comprises converting the natural gas into syngas by a pressurized reformer, which then undergoes methanol synthesis and catalytic distillation dehydration to convert raw methanol into fuel grade DME.
[0014] In order to accomplish the above object, the present invention provides a process for the production of DME comprising the following steps of:
Purging a portion of recycle gas B ( FIG. 1A ) from the H 2 membrane to the steam reformer HP burner; Simultaneously subjecting a feedstock mixture including natural gas and the remaining of the recycle gas B to the bottom of a saturator; Feeding a hot water stream to the top of the saturator and allowing the hot water to evaporate in the presence of the rising gaseous stream as it travels down the saturator. In this way, all the high pressure steam required for the downsteam reforming reactions is provided; Steam reforming the saturated natural gas and the remaining recycle gas B to produce a syngas; Recovering the heat from the reformer effluent by superheating the saturated high pressure steam to generate electric power in a syngas heat recovery boiler and superheating boiler feed water to generate superheated medium pressure steam for additional electric power generation; Directing the effluent from the medium pressure heat recovery boiler into a cooler where bulk of the water vapor in the syngas is condensed and knocked-out; Combining the compressed syngas with the methanol synthesis loop recycle gas A ( FIG. 1A ) to yield a module number of 2.05 which is the ideal module number for methanol synthesis; Subjecting the combined gas mixture to the methanol synthesis loop in the presence of Haldor Topsoe MK-121 methanol synthesis catalyst to obtain a reaction product gas mixture including methanol, carbon dioxide, water vapor, inerts like methane and nitrogen, and unconverted hydrogen and carbon monoxide; Condensing the reaction product gas mixture to separate the methanol and the water produced; Reducing the pressure of the crude methanol product to evaporate dissolved gases; Purifying the low pressure crude methanol product by a light end distillation column to strip more dissolved gases; Pumping the purified crude methanol product to a pressure of about 115 psig (9 bar) and then it is fed to a catalytic distillation dehydration column for the production of fuel grade DME.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1A is a simplified process flow diagram for the production of fuel grade DME from natural gas.
[0028] FIG. 1B is the complete turboexpander-turbocompressor system.
[0029] FIG. 2 is a simplified material balance for the natural gas to DME via the methanol dehydration route using three adiabatic methanol synthesis reactors in series.
[0030] FIG. 3 is a steam/water balance for the process of natural gas to DME via the methanol dehydration route using three adiabatic methanol synthesis reactors in series.
[0031] FIG. 4 is the operation conditions of the turboexpander-turbocompressor system.
[0032] FIG. 5 is a simplified process flow diagram for the natural gas to DME via the methanol dehydration route using a single MRF methanol synthesis reactor.
DETAILED DESCRIPTION OF THE INVENTION
[0033] For illustration purposes, a methanol synthesis loop with three adiabatic fixed bed reactors in series 8 with internal cooling between the reactors had been chosen for Example 1; and a steam-rising Multi-stage indirect cooling and Radial Flow (MRF) single methanol synthesis catalytic reactor 8 has been chosen for Example 3.
[0034] A pressurized gaseous stream of desulfurized NG and the majority of the recycle gas B from the H 2 membrane System 1 ( FIG. 1A ) is fed to the bottom of a saturator 2 while one liquid stream of hot water under pressure is fed at the top of the saturator 2 . The hot water is allowed to evaporate in the presence of the rising gaseous stream as it travels down the saturator 2 . In this way, 100% of the high pressure steam required for the downstream steam reforming reactions can be provided, which would otherwise have been supplied through high energy consumption.
[0035] The saturated natural gas and the majority of the recycle gas B stream then is preheated by the burner flue gas waste heat recovery section 3 before entering the tubular steam reformer 4 operated at 1,600° F. (871° C.) and 300 psig (21.7 bar). One method of overcoming problems of stress-rupture failures of the reformer catalyst tubes due to high temperature and high pressure operation is to use a pressurized burner in the reformer which is called pressurized reformer. Burner pressures are suitably maintained at about 100 to 250 psig (7.9 to 18.3 bar) and preferably about 150 to 200 psig (11.4 to 14.8 bar). The saturated natural gas and the majority of the recycle gas B mixture is brought to the requisite elevated temperature and supplied the endothermic heat for the steam reforming reactions by transfer of heat from the hot burner effluent gas through the metal walls of catalyst tubes. The pressurized reformer 4 is different to a conventional reformer in that the primary heat transfer mechanism is convection rather than radiation. The integrated internal heat recovery design of the pressurized reformer 4 ensures an improved fuel demand to meet reforming heat load requirements and improved overall energy efficiency. One way to compare the reformer overall energy efficiency is by the comparison of exit temperatures of reformer process gases and flue gases (Table 2). Another advantage of the pressurized reformer 4 is that it is less than a quarter of the weight and size of a conventional reformer. The uniformity of the reaction and combustion conditions of the pressurized reformer 4 avoid undesirable carbon formation and give very efficient combustion with minimum excess air for the fuel combustion, avoiding unwanted heat losses and resulting in a lower fuel consumption for a given reformer duty.
[0000]
TABLE 2
STEAM REFORMER COMPARISON
CONVENTIONAL
PRESSURIZED
Has to be field constructed
Shop fabrication to enable a high
and assembled
level of quality control & reduction
in project construction schedules
Non-transportable
Truck transportable dimensions
Thermally inefficient, heat
The primary heat transfer mechanism is
transfer is radiative
convective
Reformer process gas exit
Reformer process gas exit temperature:
temperature: about 1,600° F.
about 1,020 to 1,050° F. (549 to
(871° C.)
566° C.)
Reformer flue gas exit
Reformer flue gas exit temperatures:
temperatures: 1,825 to 1,900°
1,060 to 1,100° F. (571 to 593° C.)
F. (996 to 1,038° C.)
Fuel consumption: 100%
Fuel consumption: 46%
Size of weight of reformer:
Size & weight of reformer: less than 25%
100%
Reformer duty: 100%
Reformer duty: 75%
Reformer flue gas exit flow
Reformer flue gas exit flow rate: 3%
rate: 100%
[0036] A turboexpander 5 ( FIG. 1B ) is placed at the end of the burner flue gas waste heat recovery section 6 to recover waste energy by driving the last stage of a three-stage air compressor 7 . It helps cut the air compression energy needs by more than 40%.
[0037] A low or atmospheric pressure burner can also be used in the reformer which is called conventional reformer, and by doing so the primary heat transfer mechanism will be radiation rather than convection. The reformer process gas effluent temperature will be about 1,600° F. (871° C.) instead of about 1,020 to 1,050° F. (549 to 566° C.) and the reformer flue gas effluent temperature will be 1,825° F. (996° C.) minimum, 1,900° F. (1,038° C.) maximum instead of about 1,060 to 1,100° F. (571 to 593° C.) as shown in Table 2. Now special condition is required in design to overcome problems of stress-rupture failures of the reformer catalyst tubes due to high temperature and high pressure operations.
[0038] The sensible heat of the hot syngas produced by the pressurized reformer 4 is recovered by superheating a high pressure saturated steam for electric power generation and then superheating a medium pressure boiler feed water for additional electric power generation. This syngas is then further cooled to knockout water before it is compressed to methanol synthesis pressure (1,045 psig or 73 bar). At this point, the conventional methanol synthesis catalyst usually requires an acid gas (CO 2 and sulfur compounds) removal step to lower the CO 2 content in the syngas to be less than about 3 mol % in order to maintain the catalyst activity when natural gas is used as the carbonaceous fuel in the steam reformer and a module number of 2.05 is desired for the feed gas to the methanol synthesis loop. A solvent wash by amines, Selexol™ Rectisol™, etc. is needed. However, a high capital cost and high energy consumption are associated to pump the solvent around and to regenerate the solvent. Recently, a breakthrough of methanol synthesis catalyst named MK-121 was developed by Haldor Topsoe. MK-121 ensures very high conversion efficiency whether the synthesis gas is rich in carbon dioxide, carbon monoxide or both. Furthermore, MK-121 allows operation at lower temperatures than conventional methanol synthesis catalysts where conditions for byproduct formation is less favorable. MK-121 also has a high capacity for sulfur uptake and metal carbonyls and can in most cases, completely guard itself against residual poisons. Thus, the costly acid gas removal step before the methanol synthesis loop is eliminated permanently.
[0039] The compressed syngas sometimes called make-up syngas, is mixed with the methanol synthesis loop recycle gas A, preheated by the process gas from the last adiabatic methanol synthesis reactor 8 before it is fed to the methanol synthesis loop. The mixed methanol synthesis feed gas is characterized by the stoichiometric ratio (H 2 —CO 2 )/(CO+CO 2 ), often referred to as the module M as discussed above. A module of 2 defines a stoichiometric synthesis gas for formation of methanol. In actual cases, a slightly higher module number like 2.05 will be used. Other important properties of the synthesis gas are the CO to CO 2 molar ratio and the concentration of inerts. A high CO to CO 2 molar ratio will increase the reaction rate and the achievable per pass conversion. In addition, the formation of water will decrease, which reduces the catalyst deactivation rate. High concentration of inerts will lower the partial pressure of the active reactants. Inerts in the methanol synthesis are typically methane and nitrogen which are controlled by the purge rates from the methanol synthesis loop and from recycle gas B.
[0040] In the methanol synthesis loop, conversion of syngas into crude methanol takes place. Crude methanol is a mixture of methanol, a small amount of water, dissolved gases, and traces of byproducts. The conversion of hydrogen and carbon oxides to methanol is described by the following reactions:
[0000] CO+2H 2 →CH 3 OH ΔH 270° C. =−100.92 KJ/mol (4)
[0000] CO 2 +3H 2 →CH 3 OH+H 2 O ΔH 270° C. =−61.38 KJ/mol (5)
[0000] CO+H 2 O→CO 2 +H 2 ΔH 270° C. =−39.54 KJ/mol (6)
[0041] The methanol synthesis is exothermic and the maximum conversion is obtained at low temperature and high pressure. A challenge in the design of methanol synthesis is to remove the heat of reaction efficiently and economically. Today, six different designs of methanol synthesis reactors are commercially in operation: (1) quench reactor; (2) adiabatic reactors in series; (3) tube cooling reactor; (4) steam rising isothermal tubular bed reactor; (5) steam rising isothermal boiler coil reactor; (6) steam rising Multi-stage indirect-cooling and Radial Flow (MRF) Reactor.
[0042] In our invention, about 90 to 95% of the methanol produced is by EQ. 4, and only 5 to 10% is by EQ. 5. Another important characteristic of our invention is that a high purge rate, about 30%, is applied to the methanol synthesis loop using three adiabatic reactors in series (Example 1) and about 80% in Example 3 when a single MRF reactor is used in the methanol synthesis loop. The majority of the recycle gas B after the H 2 membrane 1 (H 2 removal step) is recycled to pick up steam in the saturator 2 and to supply the CO 2 needed for the reformer 4 to manipulate the module number for permitting optimization of the syngas composition for methanol production. The H 2 rich stream removed from the H 2 membrane 1 can either go through a PSA system to produce pure H 2 at 260 psig (19 bar) in Example 1, and at 400 psig (28.6 bar) in Example 3, or can be used as boiler fuel for the electric power/steam generation.
[0043] The process gas stream from the last adiabatic methanol synthesis reactor 8 is used to preheat the feed gas to the first reactor before it is cooled further to condense the crude methanol product. The crude methanol stream is let down in pressure from methanol synthesis pressure to about 10 psig (1.7 bar) in order to evaporate dissolved gases and then is fed to a light end distillation column 9 to strip more dissolved gases. The purified crude methanol now containing mainly methanol and water is pumped to a pressure of about 115 psig (9 bar) and is fed to a catalytic distillation dehydration column 10 for the production of fuel grade DME. The water produced from the catalytic distillation dehydration column bottom is combined with the knockout water and make-up boiler feed water and heat exchanged with the internal methanol synthesis reactor effluents before it is fed to the top of the saturator 2 ( FIG. 3 ).
[0044] Although the invention has been described with reference to its various embodiments, from this description, those skilled in the art may appreciate changes and modifications thereto, which do not depart from the scope and spirit of the invention as described herein and claimed hereafter. The following examples illustrate specific embodiments of the invention, and is not meant to limit the scope of the invention in any way.
Example 1
[0045] A combined gaseous mixture of 804.78 lbmol/hr of natural gas and 762.92 lbmol/hr of recycle gas B are fed to the bottom of a saturator, while a stream of hot water is fed at the top of the saturator ( FIG. 2 ). The rising gaseous stream evaporates the hot water as it travels down the saturator. The flow rate of the recycle gas B stream and the CO 2 concentration in the stream are manipulated to obtain 2.05 module number for the methanol synthesis feed gas and meanwhile also to evaporate enough steam in the saturator for the downstream steam reforming reactors.
[0046] The saturated natural gas and the remaining recycle gas B mixture is then preheated by the HP burner flue gas before entering the tubular steam reformer operated at 1,600° F. (871° C.) and 300 psig (21.7 bar). A syngas with the composition below is obtained (Table 3):
[0000]
TABLE 3
SYNGAS FROM PRESSURIZED STEAM REFORMER
PHASE
VAPOR
Temp., ° F. (° C.)
1,021.0 (544.4)
Pressure, psig (bar)
295 (21.4)
Flowrate, lbmol/hr
5,030.10
H 2 /CO molar ratio
3.0395
Composition
Mol %
CH 4
5.69
CO 2
5.90
N 2
1.20
H 2 O
20.91
CO
16.41
H 2
49.88
[0047] The sensible heat of the hot syngas produced by the pressurized reformer is recovered first by superheating a high pressure stream of saturated steam at 600 psig (42.4 bar) and 489° F. (253.9° C.) to 800° F. (426.7° C.) which generates 6889 hp electric power through a steam turbine, and then superheats a medium pressure boiler feed water at 290 psig (21.0 bar) and 220° F. (104.4° C.) to 671° F. (355.0° C.) which then generates an additional 682 hp electric power. The syngas is then further cooled to knockout most of its moisture content, 1,032.97 lbmol/hr before it is compressed to the methanol synthesis pressure, 1,045 psig (73.1 bar). This compressed syngas is sometimes called make-up syngas.
[0048] The make-up syngas is mixed with the methanol synthesis loop recycle gas A to obtain a methanol synthesis loop feed gas with an appropriate module number by methods as discussed above. For illustration purposes, a synthesis loop with three adiabatic fixed bed reactors in series with internal cooling between the reactors is chosen. The cooling is provided by preheat of boiler feed water or generation of medium pressure steam. The combined gas mixture is preheated by the process gas from the last adiabatic methanol synthesis reactor to 401° F. (205° C.) before it is fed to the methanol synthesis loop. A 30% purge gas rate is applied to the methanol synthesis loop and 85% of the recycle gas B is fed to the bottom of the saturator to pick up enough steam in the saturator and meanwhile to get a module number of 2.05 for the methanol synthesis feed gas. The methanol synthesis loop feed gas has the following composition (Table 4):
[0000]
TABLE 4
METHANOL SYNTHESIS LOOP FEED GAS
PHASE
VAPOR
Temp., ° F. (° C.)
401.0 (205.0)
Pressure, psig (bar)
1,018.5 (71.2)
Flowrate, lbmol/hr
8,971.74
H 2 /CO molar ratio
3.8847
Module
2.05
Composition
Mol %
CH 4
10.68
CO 2
9.50
N 2
2.27
H 2 O
0.22
CO
15.75
H 2
61.16
CH 4 O
0.42
[0049] The process gas stream from the last adiabatic methanol synthesis reactor is used to preheat the feed gas before it is cooled further to 105° F. (40.6° C.) to condense the crude methanol product which has the following composition (Table 5):
[0000]
TABLE 5
CRUDE METHANOL PRODUCT
PHASE
VAPOR
Temp., ° F. (° C.)
105.0 (40.6)
Pressure, psig (bar)
974.5 (68.2)
Flowrate, lbmol/hr
680.46
Composition
Mol %
CH 4
0.46
CO 2
4.42
N 2
0.02
H 2 O
7.47
CO
0.07
H 2
0.22
CH 4 O
87.34
Acetic Acid
13.81 ppm
Acetone
13.28 ppm
Ethanol
29.56 ppm
[0050] This crude methanol stream is let down in pressure from 974 psig (68.2 bar) to 10 psig (1.7 bar) to evaporate dissolved gases and then is fed to a 15 stage light end distillation column to strip more dissolved gases. By letting down the pressure to 10 psig (1.7 bar) instead of 120 psig (9.3 bar), it saves 82% of the condenser cooling duty and 65% of the reboiler heat duty for the light end distillation column (Table 6).
[0000]
TABLE 6
LIGHT END DISTILLATION COLUMN COMPARISON
Cases
Case 1
Case 2
Pressure, psig (bar)
120 (9.3)
10 (1.7)
Stages
15
15
Molar Reflux Ratio
2
2
Condenser Duty, Btu/hr
−1,370,906
−248,659
Reboiler Duty, Btu/hr
4,264,289
1,477,999
[0051] The bottom stream from the light end distillation column contains mainly methanol and water (Table 7).
[0000]
TABLE 7
PURIFIED CRUDE METHANOL PRODUCT
PHASE
VAPOR
Temp., ° F. (° C.)
177.2 (80.7)
Pressure, psig (bar)
11.0 (1.8)
Flowrate, lbmol/hr
637.88
Composition
Mol %
CH 4
0.00
CO 2
0.00
N 2
0.00
H 2 O
7.95
CO
0.00
H 2
0.00
CH 4 O
92.05
Acetic Acid
14.73 ppm
Acetone
13.09 ppm
Ethanol
31.33 ppm
[0052] The bottom stream is pumped to 116 psig (9 bar) and is then fed to a 30 stage catalytic distillation dehydration column (Table 8) for the production of 293.58 lbmol/hr or 162.29 ton/day of fuel grade DME.
[0000]
TABLE 8
CATALYTIC DISTILLATION DEHYDRATION COLUMN
Feed Stream
Phase
Liquid
Temp., ° F. (° C.)
177.4
(80.8)
Pressure, psig (bar)
116.4
(9)
Flowrate, lbmol/hr
637.88
Composition
Mol %
CH 4 O
92.05
H 2 O
7.95
Acetic Acid
14.73
ppm
Acetone
13.09
ppm
Ethanol
31.33
ppm
Catalytic Distillation Column
Stripping Stages
21 to 30
Total Stages
30
Rectification Stages
1 to 7
Reaction Stages
8 to 20
Feed Stage
8
Column Pressure, psig (bar)
116 (9)
Molar Reflux Ratio
9
Distillate to CH 4 O Feed Ratio
0.5
DME Purity
99.9834
mol %
99.9884
wt %
[0053] The H 2 rich stream removed from the H 2 membrane can either go through a PSA system to produce 7.70 MMSCFD of pure hydrogen at 260 psig (19 bar) or can be used as boiler fuel to produce 345 ton/day of 600 psig saturated steam for the catalytic distillation dehydration column reboiler and 6,889 HP of electric power which is about 98% of the power requirements for the entire DME plant.
[0054] The water stream produced at the catalytic distillation dehydration column bottom is 99.97 mol % or 99.94 wt % pure and there is no need for any waste water treatment. It is combined with the knockout water and make-up boiler feed water, heat exchanged with the internal methanol synthesis reactor effluents before it is fed to the top of the saturator ( FIG. 3 ).
Example 2
[0055] The pressurized furnace effluent leaving the interchanger at 467° F. (241.7° C.) and 140 psig (10.7 bar) is directed to a turboexpander to recover the waste energy by driving a turbocompressor to compress air from 52.3 psig (4.6 bar) to 166.3 psig (12.5 bar) which accounts for 41% of total air compression energy ( FIG. 4 ).
[0056] Kunio Hirotani et al. (REF. 6) disclosed an optimum catalytic reactor design for methanol synthesis called steam rising Multi-stage indirect cooling and Radial Flow (MRF) single methanol synthesis catalytic reactor, in which the heat of the highly exothermic methanol synthesis reactions over the catalyst bed is removed by means of cooling tubes arranged adequately in the bed. Due to the large cross surface area for syngas flow in a radial flow pattern, extremely small pressure drop through the catalyst bed is resulted and an ideal temperature profile is accomplished for achieving higher conversion of syngas per pass on the same volume of catalyst.
[0057] The specification of a 5,000 ton/day MRF reactor: Inlet and outlet gas compositions, operating conditions are summarized in Table 9. The last column in Table 9 is the simulated outlet gas composition by Aspen Plus Basic Engineering V7.3.
[0000]
TABLE 9
SPECIFICATION OF A 5,000 TON/DAY MRF REACTOR
Composition,
Inlet
Outlet
Simulated Out-
mol %
Gas
Gas
let Gas
H 2
83.2
77.3
77.3
CO
7.9
2.1
2.2
CO 2
5.8
4.4
4.4
CH 4 + N 2
2.7
3.2
3.2
H 2 O
0.1
2.8
2.7
CH 4 O
0.3
10.2
10.2
Total
100.0
100.0
100.0
Temperature, ° C. (° F.)
240 (464)
260 (500)
260 (500)
Pressure, bar (psig)
100 (1,436)
99 (1,421)
99 (1,421)
Example 3
[0058] In this example, the natural gas feed rate and conditions are the same as in Example 1 except that the three adiabatic methanol synthesis reactors in series are replaced by the above single MRF reactor. Due to the higher conversion of the syngas (mainly CO conversion) to methanol is achieved in the MRF reactor, a higher methanol synthesis loop recycle purge about 80% and about 5% purge of the H 2 depleted H 2 membrane recycle gas B are required to yield the ideal feed gas module number of 2.05 to the methanol synthesis loop.
[0059] In the following Table 10, the flow rates, temperatures, pressures, enthalpy, vapor fractions and component mole fractions, etc. of all the streams shown in FIG. 5 are presented. In this example, the feed gas flow rate to the methanol synthesis loop reduces from 8,971.74 lbmol/hr to 4,694.32 lbmol/hr which is 47.7% smaller. This means that for the same amount of natural gas feed rate only about half the reactor volume and catalyst are required. It is amazed to find out that even with the 47.7% smaller methanol synthesis reactor, the DME production from the same natural gas feed rate as used in Example 1 has increased from 162.29 tons/day to 178.95 tons/day.
[0000]
TABLE 10
SIMPLIFIED MATERIAL BALANCE FOR THE NATURAL GAS TO DME VIA THE METHANOL DEHYDRATION ROUTE USING A SINGLE MRF METHANOL SYNTHESIS REACTOR
Stream No.
1
2
3
4
5
6
7
8
9
Stream Name
Saturated Natural
Flue Gas
Remaining
Gas & Remaining
Purge Gas of
from Turbo
Natural Gas
Recycle Gas B
Hot Water
Recycle Gas B
Natural Gas
Air to
Recycle Gas B
Compressor
Syngas from
to Saturator
to Saturator
to Saturator
to Reformer
to HP Burner
Compressor
to HP Burner
Expander
Reformer
Total Flow lbmol/hr
804.78
868.93
1,973.22
3,660.32
284.05
3,415.00
45.73
3,743.26
5,239.86
Total Flow lb/hr
13,543.69
20,928.35
35,548.00
70,019.84
4,780.24
98,524.11
1,101.49
104,406.00
70,019.84
Total Flow cuft/hr
22,250
24,109
672
94,546
14,524
1,360,440
1,445
686,879
270,307
Temperature ° F.
400
400
420
370
400
86
79
225
1021
Pressure, psia
335
335
330
330
181
15
181
40
310
Vapor Fraction
1
1
0
1
1
1
1
1
1
Liquid Fraction
0.00
0.00
1.00
0.00
0.00
0.00
0.00
0.00
0.00
Average Mole Weight
16.83
24.09
18.02
19.13
16.83
28.85
24.09
27.89
13.36
Density lbmol/cuft
0.04
0.04
2.94
0.04
0.02
0.00
0.03
0.01
0.02
Density lb/cuft
0.61
0.87
52.94
0.74
0.33
0.07
0.76
0.15
0.26
Mole Frac
Methane, CH4
16.04
0.9520
0.3015
0.0000
0.2805
0.9520
0.0000
0.3015
0.0000
0.0542
Carbon Dioxide, CO2
44.01
0.0070
0.1939
0.0000
0.0468
0.0070
0.0000
0.1939
0.0854
0.0572
Nitrogen, N2
28.01
0.0130
0.1569
0.0000
0.0401
0.0130
0.7900
0.1569
0.7236
0.0280
Oxygen, O2
32.00
0.0000
0.0000
0.0000
0.0000
0.0000
0.2100
0.0000
0.0300
0.0000
Water, H2O
18.02
0.0000
0.0000
1.0000
0.5473
0.0000
0.0000
0.0000
0.1602
0.2070
Carbon Monoxide, CO
28.01
0.0000
0.2001
0.0000
0.0475
0.0000
0.0000
0.2001
0.0005
0.1593
Hydrogen, H2
2.02
0.0000
0.1337
0.0000
0.0317
0.0000
0.0000
0.1337
0.0002
0.4941
Methanol, CH4O
32.04
0.0000
0.0139
0.0000
0.0000
0.0000
0.0000
0.0139
0.0000
0.0000
DME, C2H6O-1
46.07
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
Ethane, C2H6
30.07
0.0250
0.0000
0.0000
0.0055
0.0250
0.0000
0.0000
0.0000
0.0000
Propane, C3H8
44.10
0.0030
0.0000
0.0000
0.0007
0.0030
0.0000
0.0000
0.0000
0.0000
Acetic Acid, C2H4O-01
60.05
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
Acetone, C3H6O-01
58.08
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
Ethanol, C2H6O-02
46.07
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
Butenol, C4H10-01
74.12
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
Enthalpy Btu/lbmol
−29638.68
−50499.93
−116550.00
−74048.62
−29611.36
60.02
−53229.89
−30050.45
−33087.79
Enthalpy Btu/lb
−1761.17
−2096.72
−6469.47
−3870.93
−1759.55
2.08
−2210.07
−1077.40
−2476.09
Enthalpy MMBtu/hr
−23853000.00
−43881000.00
−233470000.00
−271040000.00
−8411100.00
204984.00
−2434400.00
−112490000.00
−173380000.00
Entropy Btu/lbmol-R
−20.81
−0.95
−29.93
−10.66
−19.55
1.13
−3.68
−0.16
4.79
Entropy Btu/lb-R
−1.24
−0.04
−1.66
−0.56
−1.16
0.04
−0.15
−0.01
0.36
Stream No.
10
11
12
13
14
15
16
17
18
Stream Name
Make-up Syngas
Feed Gas to
Raw Methanol to
Knockout
to Methanol
Methanol
Hydrogen
Recycle
Recycle
Catalytic Distillation
DME
Water
Synthesis Loop
Synthesis Loop
to Boiler
Gas B
Gas A
Dehydration
Wastewater
Product
Total Flow lbmol/hr
1,065.28
4,174.59
4,694.34
1,164.35
914.66
519.75
689.19
365.47
323.71
Total Flow lb/hr
19,194.39
50,825.45
57,537.95
4,819.97
22,029.85
6,712.46
21,498.72
6,586.25
14,912.47
Total Flow cuft/hr
311
23,730
33,533
17,075
3,901
2,247
466
118
380
Temperature ° F.
108
275
464
125
125
108
177
349
105
Pressure, psia
280
1455
1450
435
1420
1455
131
133
131
Vapor Fraction
0
1
1
1
1
1
0
0
0
Liquid Fraction
1.00
0.00
0.00
0.00
0.00
0.00
1.00
1.00
1.00
Average Mole Weight
18.02
12.17
12.26
4.14
24.09
12.91
31.19
18.02
46.07
Density lbmol/cuft
3.42
0.18
0.14
0.07
0.23
0.23
1.48
3.09
0.85
Density lb/cuft
61.65
2.14
1.72
0.28
5.65
2.99
46.12
55.74
39.29
Mole Frac
Methane, CH4
16.04
0.0000
0.0681
0.0754
0.0029
0.3015
0.1343
0.0000
0.0000
0.0000
Carbon Dioxide, CO2
44.01
0.0001
0.0718
0.0762
0.0462
0.1939
0.1112
0.0000
0.0000
0.0000
Nitrogen, N2
28.01
0.0000
0.0352
0.0390
0.0023
0.1569
0.0703
0.0000
0.0000
0.0000
Oxygen, O2
32.00
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
Water, H2O
18.02
0.9999
0.0047
0.0042
0.0002
0.0000
0.0001
0.0605
0.9997
0.0000
Carbon Monoxide, CO
28.01
0.0000
0.2000
0.1878
0.0027
0.2001
0.0895
0.0000
0.0000
0.0000
Hydrogen, H2
2.02
0.0000
0.6202
0.6167
0.9453
0.1337
0.5883
0.0000
0.0000
0.0000
Methanol, CH4O
32.04
0.0000
0.0000
0.0007
0.0003
0.0139
0.0063
0.9394
0.0002
0.0001
DME, C2H6O-1
46.07
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.9998
Ethane, C2H6
30.07
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
Propane, C3H8
44.10
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
Acetic Acid, C2H4O-01
60.05
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
Acetone, C3H6O-01
58.08
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
Ethanol, C2H6O-02
46.07
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0001
0.0000
Butanol, C4H10-01
74.12
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
0.0000
Enthalpy Btu/lbmol
−122360.00
−22883.45
−21810.37
−7739.87
−53229.89
−27806.99
−101950.00
−117940.00
−86847.89
Enthalpy Btu/lb
−6790.70
−1879.55
−1779.44
−1869.70
−2210.07
−2153.13
−3268.25
−6544.70
−1885.26
Enthalpy MMBtu/hr
−130340000.00
−95529000.00
−102390000.00
−9011900.00
−48687000.00
−14453000.00
−70263000.00
−43105000.00
−28114000.00
Entropy Btu/lbmol-R
−38.04
−1.73
−0.31
−5.64
−7.67
−7.26
−52.94
−31.57
−74.81
Entropy Btu/lb-R
−2.11
−0.14
−0.02
−1.36
−0.32
−0.56
−1.70
−1.75
−1.62
[0060] The H 2 rich stream removed from the H 2 membrane at 420 psig (30 bar) with a flow rate of 1,164.35 lbmol/hr has the following composition (Table 11).
[0000]
TABLE 11
HYDROGEN RICH STREAM REMOVED
FROM THE HYDROGEN MEMBRANE
PHASE
VAPOR
Temp., ° F. (° C.)
125.0 (51.7)
Pressure, psig (bar)
42.00 (30.0)
Flowrate, lbmol/hr
1,164.35
Composition
Mol %
CH 4
0.29
CO 2
4.62
N 2
0.23
H 2 O
0.02
CO
0.27
H 2
94.54
CH 4 O
0.03
[0061] The H 2 rich stream removed from the H 2 membrane can either go through a PSA system to produce 7.50 MMSCFD of pure hydrogen at 400 psig (28.6 bar) or can be used as boiler fuel to produce 380 ton/day of 600 psig saturated steam for the catalytic distillation dehydration column reboiler and 6,503 HP of electric power which is about 80% of the power requirements for the entire DME plant.
[0062] Although the coupled purge rates is 80% and 5% in this example are quite different from that in Example 1i.e. 30% and 15%, the resulting inlet gases to the H 2 membrane system from both examples are quite similar both in gas compositions and flow rates (Table 12). It means that as long as the natural gas feed rate is kept constant, the same H 2 membrane system can be used for all cases when the ideal module number of 2.05 in the feed gases to the methanol synthesis loop is maintained.
[0000]
TABLE 12
COMPARISON OF INLET GASES TO THE H 2 MEMBRANE
SYSTEM BETWEEN EXAMPLES 1 AND 3
EXAMPLE
EXAMPLE 1
EXAMPLE 3
Purge Rate for the Methanol
30
80
Synthesis Loop
Purge Rate for Recycle Gas B
15
5
Inlet Gas Comp., mol %
CH 4
13.51
13.43
CO 2
11.17
11.12
N 2
2.88
7.03
H 2 O
0.02
0.01
CO
11.80
8.95
H 2
59.87
58.83
CH 4 O
0.75
0.63
TOTAL
100.00
100.00
Flow Rate, lbmol/hr
2,097
2,079
[0063] The remaining recycle gas B (S2 in FIG. 5 ) contents a CH 4 flow of 261.98 lbmol/hr which accounts for 92.16% of the CH 4 slip in the steam reformer effluent (S9 in FIG. 5 ) and meanwhile enforces a 97.09% of CH 4 conversion for the natural gas feed stream to the saturator (S1 in FIG. 5 ). The results are summarized in Table 13.
[0000]
TABLE 13
METHANE CONVERSION OF THE NATURAL GAS FEED
UNDER HIGH PRESSURE & MILD TEMPERATURE
FOR STEAM REFORMER OPERATION CONDITIONS
Phase
Vapor
Steam Reformer Operating Pressure, psig (bar)
300 (21.7)
Steam Reformer Operating Temperature, ° F. (° C.)
1,600 (871)
CH 4 Conversion of the Natural Gas Feed, %
97.09
Saturated Natural
Component
Natural
Remaining
Gas & Remaining
Syngas
Molar Flow,
Gas to
Recycle Gas B
Recycle Gas B to
from
lbmol/hr
Separator
to Saturator
Reformer
Reformer
CH 4
766.15
261.98
1,026.64
284.25
CO 2
5.63
168.48
171.23
299.94
N 2
10.46
136.33
146.75
146.75
H 2 O
0.00
0.01
2,003.23
1,084.81
CO
0.00
173.85
173.81
834.87
H 2
0.00
116.18
116.12
2,589.21
CH 4 O
0.00
12.10
0.06
0.00
C 2 H 6
20.12
0.00
20.07
0.02
C 3 H 8
2.42
0.00
2.41
0.00
TOTAL
804.78
868.93
3,660.32
5,239.85
[0064] When the natural gas feed stream is not combined with the remaining recycle gas B, then all the CH 4 slip in the steam reformer effluent will come from the natural gas feed stream and the CH 4 conversion of the natural feed stream to the saturator drops from 97.09% to 73.02% (Table 14).
[0000]
TABLE 14
METHANE CONVERSION OF THE NATURAL GAS FEED
WHEN THE REMAINING RECYCLE GAS B IS NOT COMBINED
WITH THE NATURAL GAS FEED STREAM
Phase
Vapor
Steam Reformer Operating Pressure, psig (bar)
300 (21.7)
Steam Reformer Operating Temperature, ° F. (° C.)
1,600 (871)
CH 4 Conversion of the Natural Gas Feed, %
73.02
Saturated Natural Gas
Component Molar
Natural Gas to
& Remaining Recycle
Syngas from
Flow, lbmol/hr
Separator
Gas B to Reformer
Reformer
CH 4
766.15
765.43
206.53
CO 2
5.63
4.25
153.45
N 2
10.46
10.44
10.44
H 2 O
0.00
1,516.31
760.80
CO
0.00
0.00
457.10
H 2
0.00
0.00
1,943.21
CH 4 O
0.00
0.00
0.00
C 2 H 6
20.12
20.10
0.01
C 3 H 8
2.42
2.41
0.00
TOTAL
804.78
2,318.94
3,531.54
[0065] In order to restore the high CH 4 conversion of the natural gas, the common practice of today's industrial applications is to increase the steam reformer operating temperature to 1,832° F. (1,000° C.) that improves the CH 4 conversion to 93.70%, and then reduces the steam reformer operating pressure to 200 psig (14.8 bar) that finally restores the CH 4 conversion to 97.09%. Of course, higher reformer operating temperature means higher fuel consumption; and lower syngas production pressure means higher syngas compressor compression power.
Example 4
[0066] Keeping the same operating conditions as shown in Table 9, the MRF reactor is simulated by Aspen Plus Basic Engineering V7.3 using all the feed syngases in Table 1. The simulated results are summarized in Table 15 (Example 3 data are also included in the table for comparison purposes).
[0000]
TABLE 15
SIMULATED MRF METHANOL REACTOR RESULTS USING
ALL THE FEED SYNGASES IN TABLE 1 UNDER THE SAME
OPERATING CONDITIONS AS SHOWN IN TABLE 9
Methanol
Present
Present
Synthesis
Invention
Invention
Exxon
Johnson
Processes
2
1
UNITEL
ICI
Mobil
TEC
Matthey
Feed Gas Comp., mol %
CH 4
7.49
10.68
5.74
9.33
12.05
1.35*
10.10
CO
18.76
15.75
9.08
8.70
10.31
7.90
4.89
CO 2
7.65
9.50
10.60
10.45
4.14
5.80
3.27
H 2
61.70
61.16
64.00
69.37
69.03
83.20
81.24
H 2 O
0.42
0.22
0.24
0.11
0.10
0.10
0.12
N 2
3.91
2.27
9.76
1.66
3.84
1.35*
0.00
CH 4 O
0.07
0.42
0.58
0.38
0.53
0.30
0.38
TOTAL
100.00
100.00
100.00
100.00
100.00
100.00
100.00
Outlet Gas Comp., mol %
H 2
45.7
47.1
54.6
60.1
61.0
77.3
77.3
CO
6.9
5.9
3.7
3.3
3.0
2.2
1.4
CO 2
10.0
11.2
10.2
9.6
3.7
4.4
1.9
CH 4 + N 2
16.0
17.2
18.5
13.2
19.4
3.2
11.3
H 2 O
1.3
1.7
2.7
3.2
1.4
2.7
1.9
CH 4 O
20.1
16.9
10.3
10.6
11.5
10.2
6.2
Total
100.0
100.0
100.0
100.0
100.0
100.0
100.0
Feed Gas Module
2.05
2.05
2.71
3.08
4.49
5.65
9.56
Number
Feed Gas H 2 /CO
3.28
3.88
7.05
7.97
6.70
10.53
16.62
Molar Ratio
Feed Gas CO/CO 2
2.46
1.66
0.86
0.83
2.49
1.36
1.50
Molar Ratio
CH 4 O Production
14.36
12.32
10.31
8.44
8.94
8.23
5.21
Based on 100 lbmol/hr
Feed Gas, lbmol/hr
H 2 O Production Based
1.26
1.05
2.08
2.52
1.06
2.18
1.57
on 100 lbmol/hr Feed
Gas, lbmol/hr
CO Conversion, %
74
72
66
68
76
77
75
CO 2 Conversion, %
6
11
20
24
26
38
48
*Assume equal amount of CH 4 and N 2 in the gas mixture.
[0067] Example 4 further illustrates the importance of having a module number in the feed gas to the methanol synthesis loop to be as close to 2.05 as possible. As shown in Table 15, a reduction of the module number from 5.65 (TEC) to 2.05 (Present Inventions) can increase the CH 4 O production by 50% for Present Invention 1 or 74% for Present Invention 2; and even a slightly increase of the module number to 2.71 (UNITEL) can cause a loss in CH 4 O production by 20% for Present Invention 1 or 39% for Present Invention 2.
Example 5
[0068] Same as Example 3 except that the pressurized burner in the reformer is replaced by an atmospheric pressure burner. The primary heat transfer mechanism is radiation now rather than convection. A comparison of reformer process gas effluent temperatures, reformer flue gas effluent temperatures, reformer burner pressures, reformer fuel consumption, and reformer duties, etc. are shown in Table 16.
[0000]
TABLE 16
A COMPARISON OF REFORMER PROCESS GAS EFFLUENT
TEMPERATURES, REFORMER FLUE GAS EFFLUENT
TEMPERATURES, REFORMER BURNER PRESSURES,
REFORMER FUEL CONSUMPTION, AND REFORMER
DUTIES, ETC. BETWEEN EXAMPLES 3 AND 5
EXAMPLE
EXAMPLE 3
EXAMPLE 5
Reformer burner pressure, psig (bar)
150 (11.4)
2 (1.2)
Primary heat transfer
Convective
Radiative
Reformer process gas exit temperature,
1,021 (549)
1,600 (871)
° F. (° C.)
Reformer flue gas exit temperature,
1,080 (582)
1,825 (996)
° F. (° C.)
Reformer fuel (NG) consumption,
284.05 (46%)
615.40 (100%)
lbmol/hr
Reformer duty, MMBtu/hr
79.17 (75%)
105.71 (100%)
[0069] It should be understood from the foregoing that, while particular implementations have been illustrated and described, various modifications can be made thereto and are contemplated herein. It is also not intended that the invention be limited by the specific examples provided within the specification. While the invention has been described with reference to the aforementioned specification, the descriptions and illustrations of the preferable embodiments herein are not meant to be construed in a limiting sense. Furthermore, it shall be understood that all aspects of the invention are not limited to the specific depictions, configurations or relative proportions set forth herein which depend upon a variety of conditions and variables. Various modifications in form and detail of the embodiments of the invention will be apparent to a person skilled in the art. It is therefore contemplated that the invention shall also cover any such modifications, variations and equivalents.
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Disclosed herein is a process for monetization of natural gas by producing fuel grade dimethyl ether (DME). The process includes three reactive stages with the first reactive stage being the conversion of natural gas into syngas, the second reactive stage being the conversion of syngas into crude methanol and the third reactive stage being the production of fuel grade dimethyl ether. The management and optimization of the water and steam circuits is important to maintain net overall system efficiency and mitigation of any liquid effluents.
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CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority to U.S. Provisional Application No. 60/759,033, filed Jan. 17, 2006 and titled “Community-Based Parental Controls,” which is incorporated by reference.
TECHNICAL FIELD
[0002] This disclosure relates in part to controlling access to content.
BACKGROUND
[0003] Users may access available content over the Internet through a network service provider. Some available content may be inappropriate for certain users. Accordingly, content is often rated to enable a determination of whether it is appropriate for given users.
SUMMARY
[0004] A user wanting to control network access to content from their home computer has a limited ability to determine whether a large amount of content is appropriate or inappropriate. Although other individual's judgments of appropriateness for some content may be available, the other individual's judgments may be to few in number or incompatible with the user's own view of appropriateness.
[0005] One described system enables a user to control network access to content by providing an ability to create, to join, and to apply content rating groups. The content rating groups include data useful in enabling a determination of the appropriateness or inappropriateness of individual pieces of content. Thus different content rating groups may judge or enable judgment of the appropriateness or inappropriateness of content differently. A user may select which rating group, among multiple rating groups, most accurately conforms to the user's own judgment concerning content, and the user may apply the selected rating group to future content delivered in response to content requests.
[0006] The claims listed at the end of this disclosure are to be considered part of the specification for all purposes, including providing support for any future claims.
[0007] The various aspects, implementations, and features may be implemented in a variety of manners, even if only described herein in, for example, a single manner. The various aspects, implementations, and features may be implemented using, for example, one or more of: a method; an apparatus; an apparatus for performing a method; a program or other set of instructions for performing one or more aspects, implementations, or features; an apparatus that includes a program or other set of instructions; a computer readable medium; or a propagated signal. The computer readable medium or propagated signal may include, for example, instructions, software, and other data. The various aspects, implementations, and features may also include additional components, such as, for example, a computer, a router, a server, or a peripheral device.
[0008] The details of one or more implementations are set forth in the accompanying drawings and the description below.
DESCRIPTION OF DRAWINGS
[0009] FIG. 1 illustrates an exemplary system for providing network access control.
[0010] FIG. 2 illustrates an exemplary system for providing network access control.
[0011] FIG. 3 illustrates an exemplary process for selecting and using a rating group.
[0012] FIG. 4 illustrates an exemplary process for selecting and using multiple rating groups.
[0013] FIG. 5 illustrates an exemplary network service provider for maintaining multiple rating groups.
[0014] FIG. 6 illustrates an exemplary process for creating a rating group and compiling ratings.
[0015] FIG. 7A illustrates an exemplary graphical user interface of a hierarchal ratings group selection screen.
[0016] FIG. 7B illustrates an exemplary graphical user interface of a ratings group options screen.
[0017] FIG. 7C illustrates an exemplary graphical user interface of a vote submission screen.
DETAILED DESCRIPTION
[0018] An Internet service provider enables a home personal computer to display Internet content. The Internet content may include content that one or more users of the home personal computer do not want to be made available to one or more other users of the home personal computer. Using technology described by this application, the user is made able to join or create a rating group in order to block access to such content by others.
[0019] In one implementation, the rating groups allow members to vote on whether or not pieces of content should be blocked. Because multiple members may vote on content, a large amount of content may be rated. A rating group may be specific to a group of individuals with certain interests or beliefs. A user may create their own rating group and their own preferences as to who may join and who may vote. Multiple rating groups may be joined concurrently by a user.
[0020] After joining one or more rating groups, requested content deemed inappropriate by the rating groups may be blocked. If a piece of content is requested by the home personal computer, the network access provider searches joined rating groups to determine if a rating has been assigned by any of the joined rating groups to that piece of content. If no rating has been assigned, the network service provider may or may not enable access to the requested content. If ratings exist in multiple joined rating groups, the network service provider may consult one or more of these ratings in determining whether to block or grant access to the content. In one example, for instance, the network service provider may be configured to utilize a hierarchal system to determine which rating to utilize, and thereafter, the network service provider may consult the rating to block or grant access to the content.
[0021] Referring to FIG. 1 , a system 100 is configured to provide network communication and content access according to one or more of the methods described below. System 100 includes a client 102 coupled to a network service provider 104 that is coupled to a network 106 . The network 106 also is coupled to various resources 108 - 112 .
[0022] The client 102 may include devices with which the user interacts in order to send a request for content. For example, the client 102 may be a personal computer, a laptop, a cell phone, or a personal data assistant. The client 102 also, or alternatively, may include an application, software, or instructions, with which a user interacts in order to send a request for content. The client 102 may communicate with the network service provider 104 through one or more of various methods, such as wireless networking or Ethernet cable. The network service provider 104 may include, for example, a router or a server, and may be utilized to link multiple clients 102 to the network 106 . The network service provider 104 may include parental controls by filtering requests for content with content ratings groups as described in FIGS. 2-7C to restrict content access by the user. The network 106 may include, for example, the Internet, and is coupled to various resources 108 - 112 . The resources are providers of content. Content can include various types of information, such as, for example, a webpage, a downloadable file, an email, or a message-board.
[0023] Referring to FIG. 2 , a system 200 is configured to provide network communication.
[0024] System 200 includes voting clients 212 and using clients 214 coupled to a network service provider 204 that is coupled to a network 106 .
[0025] The voting clients 212 are users that are enabled to submit votes towards the rating of content within a rating group. The voting clients 212 include client 102 as well as clients 202 and 204 . The using clients 214 are users that are enabled to use the rating of content within a rating group. The using clients 214 include clients 206 - 210 . The voting and using clients 212 - 214 may communicate with the network service provider 204 through various methods, such as wireless networking or Ethernet cable. A given client may be both a voting client 212 and a using client 214 .
[0026] The network service provider 204 may include parental controls to restrict content access by the user. The network service provider 204 includes a parental control unit 220 that maintains a plurality of rating groups 230 - 240 utilized to determine whether to provide access to resources 108 - 112 to the using clients 214 . The rating groups 230 - 240 include ratings information indicating the rating of content. When a using client 214 which is a member of one or more rating groups 230 - 240 requests access to resources 108 - 112 , the parental control unit 220 utilizes ratings within the rating groups 230 - 240 to determine whether to provide access to the requested resources 108 - 112 .
[0027] For example, rating group # 1 230 is an open community group, in which any client 102 meeting certain characteristics may provide ratings. Rating group # 2 240 is a closed community group, in which only specifically identified clients may provide ratings. The words “open” and “closed” are merely exemplary, and indicate some of the variation group membership may have. For example, group members may be specifically identified by the group creator and unchanging, group members may be limited to those clients that satisfy one or more specified characteristics/qualifications, or anyone may be allowed to join a group. Information directed toward the rating of content may be collected in various ways. For example, information directed toward the rating of content may be collected from a single user, may be collected from only voting clients 212 , may be open to collection from all clients, or may be extracted from a database of ratings.
[0028] The previous description is an example implementation of the system 200 for providing network communication and other or different elements may be included. For example, the rating groups 230 - 240 may be stored on one of the resources 108 - 112 and may be updated independently of the network service provider 104 .
[0029] Referring to FIG. 3 , a process 300 is illustrated for selecting and applying a rating. The process 300 may be used in conjunction with the system 200 of FIG. 2 and the discussion below describes the process 300 in the context of the system 200 . However, other systems may be used.
[0030] The process 300 includes a sub-process for processing a selection of a rating group. The sub-process begins when a using client 214 , such as client 102 , selects a rating group to be applied ( 305 ). The selection may include specification of an open 230 or a closed 240 rating group, although FIG. 3 is illustrated for an open group 230 . The parental control unit 220 receives the selection and associates one or more users with the selected rating group ( 310 ). Associating one or more users may include storing information identifying the client 214 that directs the parental control unit 220 to refer to at least that rating group when a using client 214 sends a request for content. The information identifying the client 214 may be stored in a table, and be linked to the appropriate rating group. Alternatively, the information identifying the client 214 may be stored in the rating group, and the rating groups may be accessed and searched to determine which rating group a particular client is associated with.
[0031] Process 300 includes another sub-process for processing a request for content. The sub-process includes the client 102 sending a request for content ( 315 ). The request for content may be for any, for example, Internet based content, such as, for example, a webpage, a downloadable file, an email, or a message-board. The parental control unit 220 receives the request for content which prompts the parental control unit 220 to determine if the client 102 is associated with a rating group ( 320 ).
[0032] If the client 102 is determined, in operation 320 , to not be associated with a rating group 230 - 240 , the parental control unit 220 redirects the request for content to the resource 108 over the network 106 ( 325 ). The resource 108 receives the request for content and sends the requested content to the client 102 over the network 106 ( 330 ). The client 102 then receives the requested content ( 335 ).
[0033] If the client 102 is determined to be associated with a rating group in operation 320 , the parental control unit 220 sends a query for the rating of the content to the open rating group 230 ( 340 ). The open rating group 230 accesses the rating for the requested content ( 345 ), and the open rating group 230 sends the rating for the requested content to the parental control unit 220 ( 350 ). The parental control unit 220 receives the rating for the requested content. Utilizing information stored about the client 102 and the received rating for the requested content, the parental control unit 220 determines and sends information based on the accessed rating to the client 102 ( 355 ). The information based on the accessed rating indicates whether the requested access to some or all of the content is, or is not, to be granted. For example, the information may include: the rating itself, the requested content (in which case the parental control unit 220 simply serves the content requested, e.g., if it satisfies the parental controls), a “blocked” display, or non-displayed information indicating that the content will not be provided. The client 102 receives the information based on the accessed rating ( 360 ).
[0034] The previous description is an example implementation of the process 300 of selecting and applying a rating, and other or different operations may be included. In some implementations, when the resource 108 receives the request for content and sends the requested content to the client 102 over the network 106 ( 330 ), the resource 108 may send the requested content to the client 102 through the parental control unit 220 where additional information is used in order to determine the information to the client ( 355 ). For example, the ratings groups 230 - 240 may utilize other rules to determine whether to block a request. Other rules may include automatically denying requests in which certain words or phrases are present in the requested content. The words or phrases may be kept in a content ratings group list which may be open or closed to editing by group member.
[0035] Also, if no rating is found for the requested content, the network access provider may or may not provide access to that content.
[0036] Referring to FIG. 4 , process 400 is shown to illustrate selecting multiple rating groups and applying content ratings that are established by one or more of the multiple rating groups for requested content. The process 400 may be used in conjunction with the system 200 of FIG. 2 and the discussion below describes the process 400 in the context of the system 200 . However, other systems may be used.
[0037] The process 400 includes a client 102 that enables a selection of multiple rating groups to be applied to content requests ( 405 ). The selection may include specification of an open 230 or a closed 240 rating group and includes one primary rating group (shown in FIG. 4 as rating group 230 ) and one or more secondary rating groups ( FIG. 4 shows one secondary rating group of rating group 240 ). The user may be allowed to designate the primary and secondary rating groups, or such designation may be made by, e.g., the parental control unit 220 . As explained below, the primary rating group is the rating group that is first accessed by the parental control unit 220 in order to select a rating for particular requested content. If the primary rating group does not include a rating for the particular requested content, the parental control unit 220 applies a rating established by the secondary rating group. The parental control unit 220 receives the selection and associates one or more users with the selected rating groups ( 410 ). Associating one or more users may include storing information in the rating groups that directs the parental control unit 220 to refer to those rating groups when the user sends a requests for content.
[0038] The process 400 includes the client 102 sending a request for content ( 415 ). The request for content may be for any, for example, Internet based content, such as, for example, a webpage, a downloadable file, an email, or a message-board. The parental control unit 220 receives the request for content which prompts the parental control unit 220 to determine if the client 102 is associated with a rating group ( 420 ).
[0039] If it is determined in operation 420 that the client 102 is not associated with a rating group 230 - 240 , the parental control unit 220 redirects the request for content to the resource through the network 106 ( 425 ). The resource 108 receives the request for content and sends the requested content to the client 102 ( 430 ) through the network 106 . The client 102 then receives the requested content ( 435 ).
[0040] If it is determined in operation 420 that the client 102 is associated with a rating group, the parental control unit 220 sends a query for a rating of the requested content to the primary open rating group 230 ( 440 ). The primary open rating group 230 determines whether a rating for the requested content is established by the primary open rating group 230 ( 445 ).
[0041] If it is determined in operation 445 that a rating for the requested content is established by the primary open rating group 230 , the rating established by the primary open rating group 230 is sent to the parental control unit 220 ( 450 ). The parental control unit 220 receives the rating for the requested content. Using information stored about the client and the received rating for the requested content, the parental control unit 220 determines and sends information for example, as discussed with respect to operation 355 , based on the accessed rating to the client 102 ( 455 ). The information based on the accessed rating indicates whether some or all of the requested content is or is not to be blocked, and may include information detailing a lack of stored rating for the requested content. The client 102 receives the information based on the accessed rating ( 460 ).
[0042] If it is determined in operation 445 that a rating for the requested content is not established by the primary rating open group 230 , process 400 determines whether a rating for the requested content is established by the secondary closed rating group 240 ( 465 ). If it is determined in operation 465 that a rating for the requested content is established by the secondary closed rating group 240 , then the rating is sent to the parental control unit 220 ( 468 ).
[0043] A user may set up multiple rating groups to be applied in a specified, or hierarchical, order. For example, as indicated in FIG. 4 , a first rating group 230 is searched for a rating for particular content. If a rating is not found, then a second closed rating group 240 is searched. Tertiary, and further, rating groups may also be designated by, for example, a user. Additionally, the decision at any point in the hierarchy may require input from multiple rating groups. Moreover, if multiple secondary rating groups are associated with the user (not shown), each of the multiple secondary rating groups may be accessed to determine a rating for the requested content, and the ratings may be combined to form a final rating. The combination may include, for example, taking an average or a median or using some other mathematical or logical operation.
[0044] Process 400 includes the parental control unit 220 receiving the rating for the requested content, using information stored about the client and the received rating to determine information based on the accessed rating, and sending the information to the client 102 ( 470 ). The information based on the accessed rating indicates whether the requested access to some or all of the content is or is not to be granted. The client 102 receives the information based on the accessed rating ( 475 ).
[0045] If it is determined in operation 465 that a rating for the requested content is not established by the secondary closed rating group 240 , the requested content is sent to the client 102 ( 430 ). Other implementations, however, may block the requested content.
[0046] The previous description is an example implementation of the process 400 of selecting and applying a rating, and other or different operations may be included. For example, multiple hierarchies of ratings groups beyond a primary and secondary may be employed. Further, selected ratings may be based on all available ratings, such as, for example, by selections the most common rating for the requested content from among the available ratings.
[0047] Referring to FIG. 5 , system 500 includes the network service provider 204 , which includes a parental control unit 220 , and compiled ratings for a first open rating group 230 and a second closed rating group 240 .
[0048] The first open rating group 230 includes various categories such as a content category 232 describing a piece of content, several user rating categories 234 a - c , and an overall rating category for the rating group 238 . The first rating open group 230 includes three entries 233 , organized as three rows 233 a - c . An entry for the content category 232 in the first row 233 a is listed as “Content #1” and includes descriptive information, including, for example, the piece of content's location. The user rating entries 234 a - c for the first row 233 a are listed as 4 , 5 , and 6 , respectively, and the overall rating 238 is listed as 5 which is an average value.
[0049] The first open rating group 230 also may include weights (e.g. between zero and one, inclusive) for each of the user rating categories 234 a - c , which weighting may be the same or different. In the example shown in FIG. 5 , each of the user rating categories 234 a - c are weighted equally. In another example, user rating category 234 a may be weighted twice as much as user rating categories 234 b - c , which would produce an overall rating 238 of 4.75.
[0050] Weights may vary based on, for example, the authority, the judgment, the position, or the trustworthiness of the user contributing the ratings. An individual that created the first rating open group 230 , or individuals satisfying all of the desirable characteristics of rating contributors, or particularly designated individuals (e.g. the nuclear members of a family), may be given higher weights. For example, rules may direct users that have been members for a given amount of time or are more active, may be given more weight than less active or newer members. Also, a member which consistently votes against the majority or members who consistently vote to allow all content may be given less or no weight.
[0051] The previous description is an example implementation of the system 500 including a network service provider and compiled rankings. Other implementations may be organized differently and may include different or fewer elements. The value of the overall rating 239 may be computed by a method other than averaging each individual value for the entry ratings 236 . For example, weights as described above may be associated with each vote and included in the computation. Also, non-linear computations or regression of weights or votes, such as where larger deviations are minimized (e.g. “least squares” or quadratic), may be included to minimize the effect of votes that are significantly different than the majority.
[0052] Referring to FIG. 6 , process 600 enables creation of a rating group and compilation of ratings. The process 600 may be used in conjunction with the system 200 of FIG. 2 and the discussion below describes the process 600 in the context of the system 200 . However, other systems may be used.
[0053] The process 600 includes a client 102 sending a request to create a rating group ( 605 ). The request includes characteristics associated with the rating group. The parental control unit 220 receives the request to create the rating group and also receives the characteristics associated with the request for the rating group. The associated characteristics are used by parental control unit 220 to determine properties of the rating group such as, for example, whether the rating group is open or closed, the method of vote computation to determine overall ratings for content, and the requirements needed for a user to join the rating group. A closed group may, for example, only enable users of certain names or characteristics to join. The parental control unit 220 forms the rating group ( 610 ), and the rating group is added to a set of previously established rating groups ( 615 ).
[0054] Process 600 includes a separate sub-process for processing a request to join the new group. The sub-process includes a client 202 sending a request to the parental control unit 220 to join the rating group on behalf of user # 2 ( 620 ). The parental control unit 220 receives the request and verifies that user # 2 satisfies the required characteristics of the rating group ( 625 ).
[0055] If user # 2 satisfies the required characteristics of the rating group, user # 2 is added to the rating group ( 630 ). If user # 2 does not satisfy the required characteristics of the rating group in operation 625 , then user # 2 's request to join the rating group is denied by the parental control unit 220 ( 632 ), and the denial is received by the client 202 ( 634 ).
[0056] Process 600 includes another separate sub-process for receiving and processing a rating. The sub-process includes the client 202 sending a rating for a particular piece of content on behalf of user # 2 to the parental control unit 220 ( 635 ). The parental control unit 220 receives the rating ( 637 ), and determines whether user # 2 belongs to the rating group ( 638 ). If user # 2 belongs to the rating group, then the parental control unit 220 associates user # 2 's rating with the rating group ( 640 ). Associating a rating with a rating group may include weighting the user # 2 rating to an appropriate value. Further, the overall rating for the particular piece of content is updated and compiled ( 650 ). If user # 2 does not belong to the rating group, then the parental control unit 220 denies the rating submission from user # 2 ( 660 ).
[0057] The previous description is an example implementation of the process 600 of creating a rating group and compiling ratings, and other or different operations may be included. For example, an open rating group 230 could be created that has no required characteristics, or in which there are desired characteristics that are not enforced.
[0058] Implementations may also allow a rating group to be provided by a third party, such as, for example, a recognized group with a known ideology. Users may prefer to select such a known rating group as, for example, one of several hierarchically organized rating groups. Depending on various factors, such as the availability of ratings from such known rating groups, users may be charged a fee for access to ratings from the known rating group. Implementations may also allow users to contribute ratings to the known rating group, perhaps requiring that these users meet various qualifications or pay a fee.
[0059] Implementations may also provide an administrative user in a rating group, with privileges beyond the privileges extended to other users that are members of the rating group. For example, the administrative user may be required to approve or reject (1) all (or some, e.g., based on designated criteria) users before those users are allowed to become members of the rating group, (2) all ratings of content (or some, e.g., ratings of particular content) from members, (3) all compiled ratings of content, wherein the compiled ratings are compiled from the member's ratings, or (4) only specific compiled ratings, such as, for example, ratings that indicate that content is suitable for all audiences.
[0060] Other implementations do not explicitly require a user to join a rating group in order to rate content. One implementation allows a user to identify itself and to submit content ratings. These rating are made available as a rating group. Thus, for example, a user # 1 may notice that a user # 2 has submitted various ratings. If user # 1 trusts the ratings of user # 2 , then user # 1 may designate user # 2 as a rating group to be applied as access control to content requests from user # 1 (or from other users, for example, under the supervision of user # 1 ). Further, user # 1 may notice that multiple users have submitted ratings, and if user # 1 trusts all of the multiple users, then user # 1 may designate that an average (for example) be taken over the ratings of all of the multiple users, and this average may then be applied as an access control rule for content requests from user # 1 (or from other users, for example, under the supervision of user # 1 ).
[0061] As is evident from the breadth of the disclosure, implementations, features, and techniques described herein, as well as variations or combinations of them, may be implemented at least in part, for example, in an operating system or in a stand-alone application or utility, running on one or more of a variety of devices. Such devices may include, for example, a personal computer, a server, a router, a gateway, or a special-purpose computer or machine. Moreover a device may also include, for example, discrete or integrated hardware, firmware, and software. A device may include, for example, a processor, which refers to processing devices in general, including, for example, a microprocessor, an integrated circuit, a programmable logic device, and a device containing a software application.
[0062] Such a device may be configured to perform one or more processes. For example, implementations may be embodied in a device that includes one or more computer readable media having instructions for carrying out one or more processes. The computer readable medium may include, for example, a storage device such as, for example, a hard disk, a compact diskette, a random access memory (“RAM”), and a read-only memory (“ROM”). A computer readable medium also may include, for example, formatted electromagnetic waves encoding or transmitting instructions. Instructions may be, for example, in hardware, firmware, software, and in an electromagnetic wave. Instructions may be found in, for example, an operating system, a separate application, or a combination of the two. A processor may be, for example, both a device configured to carry out a process and a device including computer readable media having instructions for carrying out a process.
[0063] Referring to FIG. 7A , an exemplary graphical user interface (GUI) of a hierarchal ratings group selection screen 700 includes main entries 705 that may contain one or more levels of sub-category entries 715 and 720 and group selection options 735 and 740 .
[0064] The GUI 700 enables a user to browse and select ratings groups through a hierarchal selection process. The top level 705 displays general categories of ratings groups. The main entries 705 include a title, such as the religions entry 710 , that describes the nature of the material that is rated. Each of the main entries 705 may include the number of ratings groups that are sub-categories to the entry. The religions entry 710 and the included sub-categories 715 and 725 include ratings that are adapted to user preferences based on a religious motivation, and may or may not include ratings based on other motivations. For example, a ratings group within the religions entry 710 , may deny a request for blasphemous subject matter, but may not deny a request for violent subject matter.
[0065] Located within the religions entry 710 are multiple religions sub-categories 715 , such as Christian 720 . The Christian sub-category entry 720 includes three further sub-category entries 725 . The Baptist entry 730 is a sub-category of the Christian entry 720 and includes ratings that are adapted to user preferences based on a christian religious motivation, and in particular, based on a Baptist motivation. The Baptist entry 730 includes the number of group members (shown as 1300 ) and may include the number of voting member (not-shown).
[0066] The selection option 735 and 740 enable a user to select a ratings group and include a “join primary option” 735 , and a “join secondary option” 740 . The “join primary option” 735 enables a user to specify a chosen rating group as the primary rating group. The “join secondary option” enables a user to specify a chosen rating group as a secondary rating group.
[0067] In one implementation, entries that are higher in hierarchy than a sub-category entry are separate ratings groups that function independently of the sub-category entries. In another implementation, entries that are higher in hierarchy than a sub-category entry may include a ratings group that include rating votes of the sub-categories. The ratings votes of the sub-categories may by included in various ways. For example, the religions entry 710 may deny any request that would be denied by any of the sub-category entries 715 . Also, the religions entry 710 may deny any request that would be denied by all or a combination of the sub-category entries 715 . Further, the religions entry 710 may calculate an average or weighted average of the sub-category entries 715 ratings to determine whether to deny a request.
[0068] The previous description illustrates one of various implementations of a ratings group selection screen. Other implementations may be organized differently and may include different or fewer elements. For example, the entries may be organized in a non-hierarchal order, such as alphabetically.
[0069] Referring to FIG. 7B , a GUI of a ratings group information screen 750 includes a detailed group information section 760 , a group summary section 770 , a group voting requirements section 775 , and a group options section 780 .
[0070] The detailed group information section 760 includes information detailing information about the ratings group and includes a group hierarchal order 762 , a descriptive icon 764 , and a group statistics section 766 . The group hierarchal order 762 details the location, within a group hierarchy, of the selected ratings group. The descriptive icon 764 includes a picture that illustrates the subject matter the ratings groups is directed to. The group statistics section 766 includes information such as the number of current members and the number of voting members.
[0071] The group summary section 770 includes a written summary of the subject matter allowed or denied by the group. For example, the written summary may specify that one subject matter is allowable while another subject matter is blocked.
[0072] The voting requirements section 775 includes a written description of the requirements of members to vote on content ratings. For example, a voting requirements section 775 may detail a length of time required by members and/or whose approval is necessary to be able to vote.
[0073] The group options section 780 includes options directed to the group that may be selected. For example, the options may include joining the group as a primary or secondary group, or requesting voting privileges for the group.
[0074] The previous description illustrates one of various implementations of a ratings group information screen. Other implementations may be organized differently and may include different or fewer elements. For example, contact information for group administrators may be included in the detailed group information section 760 .
[0075] Referring to FIG. 7C , a GUI of a vote submission screen 790 includes a content snapshot 792 , a main voting option 794 , and a secondary voting option 796 . The content snapshot 792 includes an illustration or screenshot of the content the vote is directed to. The screenshot may be, for example, a screenshot of a website or a still shot of a multimedia file. The main voting option 794 enables the user to submit a vote directed to a piece of content. The vote may be, for example, whether the content includes a graphic violence. The secondary voting option 794 enables users to submit votes concerning characteristics that may be related to other ratings groups. The secondary vote may be, for example, whether the content includes nudity or adult language.
[0076] The previous description illustrates one of various implementations of a vote submission screen. Other implementations may be organized differently and may include different or fewer elements. For example, the main voting option 794 may include a vote of a number between 1-10 instead of a ‘yes’ or ‘no.’ Also, the main voting option 794 may have multiple voting option per submission that may adapt to received response. For example, if a user submits a ‘yes’ response designating the content includes graphic violence, a more detailed question may be presented, such as, “how graphic on a scale of 1-10 is the violence in the subject matter?”
[0077] A number of implementations have been described. Nevertheless, it will be understood that various modifications may be made. For example, elements of different implementations may be combined, supplemented, modified, or removed to produce other implementations. Further, various technologies may be used, combined, and modified to produce an implementation. Accordingly, other implementations are within the scope of the following claims.
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According to a general aspect, a method includes maintaining rating groups, each rating group providing a rating for content compiled based on information received from a user evaluating the content. The method also includes receiving, from a first user, a selection of a first rating group, from among the rating groups, to be applied to a set of users associated with the first user. The method also includes receiving, from a user, a request for a piece of content from the content. The method also includes determining that the user from which the request was received belongs to the set of users associated with the first user. The method also includes, based upon the determination that the user belonged to the set of users associated with the first user, accessing information associated with the first rating group and determining whether the first rating group includes a rating for the requested piece of content. The method also includes determining whether or not to provide information to the requesting user conditioned on the indication or absence of a rating for the requested piece of content within the first rating group.
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FIELD OF THE INVENTION
This invention relates to a method and an apparatus of forming thin films, which is characterized by connecting a physical vapor deposition device and a chemical vapor deposition device, which is small and requires a short thin-film formation time.
BACKGROUND OF THE INVENTION
Recently, the technique has been eagerly developed to process various materials of conductor, semiconductor, dielectrics, magnetic body, and superconductor into thin films to be used to manufacture thin film devices. Large numbers of apparatus for forming a thin film have been developed according to the objective. Among them, there is an apparatus of forming thin films which can perform a physical vapor deposition and a chemical vapor deposition in the same chamber (e.g., Laid-open Japanese Patent Application No. (Tokkai Hei) 5-109655). We manufactured a thin-film formation apparatus with the same principle shown in FIG. 5. This apparatus is configured such that an electrode integrated with a substrate heater 51 and an electrode 52 are disposed inside a reaction chamber 50, and the electrode 52 is connected to a high-frequency generator (rf (radio-frequency) generator) 53. Also, a substrate 54 is placed on the electrode integrated with a substrate heater 51, and the substrate heater integrated electrode 51 is rotated during the film formation by a substrate rotary system 55. 56 represents an exhaust system for enhancing a vacuum degree inside the reaction chamber 50. 57 represents a pipe for letting in vapor which arised by vaporizing a starting material through heating during the chemical vapor deposition. When a thin film capacitor comprising one kind of thin film device shown in FIG. 6 is manufactured using this thin-film formation apparatus, argon gas (throughput 2 SCCM) comprising an inactive gas is first let in from the pipe 57 for sputtering. Furthermore, on the upper part of the electrode 52, a target 58 for sputtering a lower electrode material such as platinum is fixed, and a lower electrode 59 such as platinum is formed on top of the substrate 54 by means of an rf sputtering method, which is one of the physical vapor deposition methods. At this time, the temperature of the substrate 54 is about 600° C., and the gas pressure inside the reaction chamber 50 is about 1.4 Pa. Next, a dielectric film 60 such as Ba 1-x Sr x TiO 3 is formed on the surface of the lower electrode 59 by a plasma chemical vapor deposition method. This film is formed by generating plasma while letting in from the pipe 57 the vapor of the starting material (barium, strontium, organometal compound of titanium), reactive gas (oxygen), and carrier gas (argon). At this time, the temperature of the substrate 54 is about 600° C., and the gas pressure inside the reaction chamber 50 is about 7 Pa. Finally, an upper electrode 61 such as platinum is formed on the surface of the dielectric film 60 under the same conditions as those with the lower electrode 59.
In addition, it is common to perform the physical vapor deposition and the chemical vapor deposition in separate devices.
In the above-mentioned conventional technique, there was a problem when a thin film device was manufactured with a thin film formation apparatus which performed the physical vapor deposition and the chemical vapor deposition in the same chamber. Namely, when a thin film is formed by the physical vapor deposition method after a thin film is formed by the chemical vapor deposition method, it took an extremely long time to clean the inner walls of the chamber or electrodes for increasing the vacuum degree. This was due to the fact that the vapor, which was led in by vaporizing the starting material through heating during the chemical vapor deposition, is cooled, caked again, and remains attached on the inner walls of the chamber or on the electrodes. Another problem was that, when the physical vapor deposition and the chemical vapor deposition are to be performed in separate devices, it was necessary to secure a large area for the installation.
SUMMARY OF THE INVENTION
It is an object of this invention to solve the above-mentioned problems in the conventional system by providing a method and an apparatus of forming thin films, which is small and requires a short thin-film formation time.
In order to accomplish these and other objects and advantages, an apparatus of forming thin films of this invention comprises at least one physical vapor deposition device and at least one chemical vapor deposition device, wherein said physical vapor deposition device and said chemical vapor deposition device are provided with an exhaust pipe respectively for connection with a common exhaust means and an exhaust switching means.
Next, this invention includes a method of forming thin films using a thin film formation apparatus comprising at least one physical vapor deposition device, at least one chemical vapor deposition device, and a common exhaust means, and comprises the steps of connecting the exhaust means via an exhaust switching means and an exhaust pipe to one of said vapor deposition devices, performing a deposition on a substrate surface, connecting the exhaust means via the exhaust switching means and an exhaust pipe to the other vapor deposition device, and further performing a deposition on the substrate surface.
It is preferable that a connection part is disposed at least at one of exhaust pipes which are present between the exhaust switching means and the physical vapor deposition device and between the exhaust switching means and the chemical vapor deposition device.
Furthermore, it is preferable that a substrate transfer passage having at least one switch valve is connected between at least one physical vapor deposition device and at least one chemical vapor deposition device, and a substrate transfer system for forwarding a substrate through the substrate transfer passage is connected to said physical vapor deposition device or said chemical vapor deposition device.
In addition, it is preferable that a thin film is formed on a substrate surface by either said physical vapor deposition device or said chemical vapor deposition device, said both vapor deposition devices are exhausted, said substrate is forwarded to the other vapor deposition device of said two vapor deposition devices through said substrate transfer passage having a switch valve using said substrate transfer system, and a thin film is formed on the substrate surface, thereby forming thin films without exposing the substrate to the air.
It is preferable that the physical vapor deposition device forms a thin film without a chemical reaction by solidifying a gas or ion of a material to be formed into a thin film on a substrate surface.
Furthermore, it is preferable that the physical vapor deposition device comprises one device selected from the group consisting of a vacuum vapor deposition device, an ion plating device, a sputtering device, an ion-containing vapor deposition device, a reactive ion plating device, and a molecular beam epitaxy device.
In addition, it is preferable that the chemical vapor deposition device forms a thin film by providing a gas of a compound comprising composite elements of a material to be formed into a thin film on a substrate surface, and by allowing a chemical reaction to take place inside the gaseous phase or on the substrate surface.
Also, it is preferable that the chemical vapor deposition device comprises one device selected from the group consisting of a thermal CVD (chemical vapor deposition) device, a plasma CVD device, a MOCVD (metalorganic chemical vapor deposition) device, and a plasma MOCVD device.
It is preferable that the physical vapor deposition device comprises at least one device selected from a vacuum vapor deposition device, a sputtering device, and an ion plating device, and that the chemical vapor deposition device comprises either a plasma chemical vapor deposition device or a thermal chemical vapor deposition device.
According to the apparatus of forming thin films of this invention, the apparatus comprises at least one physical vapor deposition device and at least one chemical vapor deposition device, wherein said physical vapor deposition device and said chemical vapor deposition device are provided with an exhaust pipe respectively for connection with a common exhaust means and an exhaust switching means. As a result, an apparatus for forming thin films, which is small and requires a short thin-film formation time, can be attained, together with a method forming thin films. In particular, according to the configuration in which the exhaust switching means is connected to the physical vapor deposition device, to the chemical vapor deposition device, and to an exhaust means via exhaust pipes, this apparatus can be accomplished with a small size, which has at least two chambers and one exhaust means. In this way, thin films can be formed in a short film formation time with a small apparatus, since vapor of a starting material which is led in at the time of chemical vapor deposition does not enter the physical vapor deposition device.
The following effects can be obtained by this invention:
(1) The apparatus of forming thin films is configured such that the exhaust switching means is connected to the physical vapor deposition device, to the chemical vapor deposition device, and to an exhaust means via exhaust pipes, so that vapor of a starting material which is led in at the time of chemical vapor deposition can be prevented from attaching and remaining in the physical vapor deposition device. Thus, the thin-film formation time can be reduced considerably.
(2) The apparatus of forming thin films is configured such that the exhaust switching means is connected to the physical vapor deposition device, to the chemical vapor deposition device, and to an exhaust means via exhaust pipes, and a substrate transfer passage having at least one switch valve is connected between the physical vapor deposition device and the chemical vapor deposition device, and a substrate transfer system for forwarding a substrate through the substrate transfer passage is connected to the physical vapor deposition device or the chemical vapor deposition device, so that the thin-film formation time can be reduced considerably.
(3) According to this invention, a small apparatus of forming thin films which requires a small area for installation can be obtained.
(4) The method of forming thin films using a thin-film formation apparatus, which comprises the exhaust switching means is connected to the physical vapor deposition device, to the chemical vapor deposition device, and to an exhaust means via exhaust pipes, a substrate transfer passage having a switch valve connected between the physical vapor deposition device and the chemical vapor deposition device, and a substrate transfer system for forwarding a substrate through the substrate transfer passage connected to the physical vapor deposition device or the chemical vapor deposition device, comprises the steps of forming a thin film on a substrate surface by either the physical vapor deposition device or the chemical vapor deposition device, exhausting the physical vapor deposition device and the chemical vapor deposition device, forwarding the substrate from the physical vapor deposition device to the chemical vapor deposition device or from the chemical vapor deposition device to the physical vapor deposition device through the substrate transfer passage having a switch valve using the substrate transfer system, and forming a thin film on the substrate surface, thereby forming thin films without exposing the substrate to the air. As a result, the thin film formation time can be reduced considerably, and thin films which have less difference in properties can be formed.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a cross-sectional view showing an apparatus of forming thin films in Example 1 of this invention.
FIG. 2 is a cross-sectional view showing an apparatus of forming thin films in Example 2 of this invention.
FIG. 3 is a cross-sectional view showing an apparatus of forming thin films in Example 3 of this invention.
FIG. 4 is a cross-sectional view showing an apparatus of forming thin films in Example 4 of this invention.
FIG. 5 is a cross-sectional view showing a conventional apparatus of forming thin films.
FIG. 6 is a cross-sectional view of a thin film capacitor.
DETAILED DESCRIPTION OF THE INVENTION
This invention will be described in detail by referring to the following examples and attached figures. The examples are illustrative and should not be construed as limiting the invention in any way.
EXAMPLE 1
In FIG. 1, reference numeral 1 represents an exhaust switching means, which is connected to a physical vapor deposition device 3 via an exhaust pipe 2a, to a chemical vapor deposition device 4 via an exhaust pipe 2b, and to an exhaust means 5 via an exhaust pipe 2c. As for the composite elements which have the same function as that in the conventional thin film formation apparatus shown in FIG. 5, they are provided with the same reference numerals.
A method of manufacturing thin films capacitor shown in FIG. 6 will be explained by referring to FIG. 1.
First, a silicon substrate 54 was fixed to an electrode integrated with a substrate heater 51 which was disposed in an rf magnetron sputtering device 3 as one physical vapor deposition device. Next, a high-frequency generator 53 was connected to an electrode 52 which has a platinum target 58 fixed on its upper surface. Subsequently, by means of the exhaust switching means 1, the rf magnetron sputtering device 3 and a turbo molecular pump 5 comprising one exhaust means were connected via the exhaust pipes 2a and 2c, and the reactive chamber 50 was exhausted until the gas pressure reached about 0.5 Pa. Then, argon gas as an inactive gas (throughput 2 SCCM) for sputtering was let in through a sputter gas inlet pipe 62, and the silicon substrate 54 was heated at about 600° C . Also, when 50 W of plasma power was applied for 14 minutes by the high-frequency generator 53 (13.56 MHz) while rotating by a substrate rotary system 55, a lower electrode 59 made of platinum was formed with a thickness of about 100 nm. At this moment, the gas pressure inside the reactive chamber 50 was 1.4 Pa.
Next, the silicon substrate 54 formed on the lower electrode 59 of platinum was taken out by breaking the vacuum inside the rf magnetron sputtering device 3, and this silicon substrate 54 was installed to an electrode integrated with a substrate heater 51 inside a plasma chemical vapor deposition device 4 as one chemical vapor deposition device. Subsequently, by means of an exhaust switching means 1, the plasma chemical vapor deposition device 4 and the turbo molecular pump 5 were connected via the exhaust pipes 2b and 2c, and the reactive chamber 50 was exhausted until the gas pressure reached about 3 Pa. Next, for forming a dielectric film 60, each of the vapors which resulted from heating barium dipivaloylmethane {Ba(DPM) 2 , DPM=C 5 H 7 O 2 } (solid at room temperature), strontium dipivaloylmethane {Sr(DPM) 2 } (solid at room temperature), and tetraisopropoxy titanium {Ti(C 3 H 7 O) 4 } (liquid at room temperature) as the starting material was let into the reactive chamber 50 from a pipe 57 together with argon carrier gas (each throughput is 25, 25, 5 SCCM) and oxygen as a reactive gas (throughput is 10 SCCM). At this moment, the gas pressure inside the reactive chamber 50 was about 7 Pa. Then, the silicon substrate 54 was heated at about 600° C., and when 1.4 W/cm 2 of plasma power was applied for 16 minutes by the high-frequency generator 53 while rotating by the substrate rotary system 55, the dielectric thin film 60 made of Ba 1-x Sr x TiO 3 was formed with a thickness of about 2 μm.
Subsequently, the silicon substrate 54 having the dielectric thin film 60 formed on the lower electrode 59 was taken out by breaking the vacuum inside the plasma chemical vapor deposition device 4, and this silicon substrate 54 was once again fixed to the electrode integrated with a substrate heater 51 in the rf magnetron sputtering device 3. In this way, an upper electrode 61 was formed under the same conditions as those when the lower electrode 59 of platinum had been formed. In this instance, since the vapor of the starting material which was led in during the chemical vapor deposition did not enter the rf magnetron sputtering device 3, it was unnecessary to clean the inner walls of the chamber or the electrodes. Therefore, an upper electrode could be formed immediately after the dielectric film was formed. As a result, compared with a conventional thin film formation apparatus which performs the physical vapor deposition and the chemical vapor deposition in the same chamber, thin films could be formed with an extremely short time. Furthermore, this configuration had the advantage of reducing the area needed to install the apparatus, compared with performing the physical vapor deposition and the chemical vapor deposition in separate devices.
EXAMPLE 2
Another embodiment of this invention will be explained by referring to FIG. 2.
This embodiment differs from the embodiment of FIG. 1 in that a connection part 6 is disposed at the exhaust pipe 2a between the exhaust switching means 1 and the rf magnetron sputtering device 3.
This configuration has the advantage of separating the rf magnetron sputtering device at the connection part 6 and exchanging it easily with other physical vapor deposition devices.
Furthermore, the connection part 6 may be disposed at the exhaust pipe 2b of between the exhaust switching means 1 and the plasma chemical vapor deposition device 4. Also, the device to be exchanged may be other chemical vapor deposition devices.
EXAMPLE 3
Another embodiment of this invention will be explained by referring to FIG. 3.
This embodiment differs from the embodiment of FIG. 1 in that a substrate transfer passage 8 having a switch valve 7 is connected between the rf magnetron sputtering device 3 and the plasma chemical vapor deposition device 4, and also that a substrate transfer system 9 is connected to the plasma chemical vapor deposition device 4.
Furthermore, this method of forming thin films differs in that thin films can be formed without exposing the substrate to the air. In other words, the switch valve 7 was closed, and the lower electrode 59 was formed inside the rf magnetron sputtering device 3 on the silicon substrate 54 according to the same method as in Example 1, and then, after switching the exhaust switching means 1 to the side of the plasma chemical vapor deposition device 4 and exhausting it. The switch valve 7 was opened, and the silicon substrate 54 was forwarded to the side of the plasma chemical vapor deposition device 4 through the substrate transfer passage 8 by the substrate transfer system 9. Next, the switch valve 7 was closed, and the dielectric thin film 60 of Ba 1-x Sr x TiO 3 was formed on the lower electrode 59 according to the same method as in Example 1 through plasma chemical vapor deposition. After the dielectric thin film 60 was formed, the plasma chemical vapor deposition device 4 was sufficiently exhausted. While keeping the switch valve 7 closed, the exhaust switch means 1 was switched to the side of the rf magnetron sputtering device 3, which was then exhausted. Subsequently, the switch valve 7 was opened, and the silicon substrate 54 was forwarded once again to the side of the rf magnetron sputtering device 3 through the substrate transfer passage 8 by the substrate transfer system 9. Next, the switch valve 7 was closed, and the upper electrode 61 was formed inside the rf magnetron sputtering device 3 on the dielectric thin film 60 of Ba 1-x Sr x TiO 3 with the same method as in Example 1.
According to the above-mentioned confirmation, it is clear that the apparatus of forming thin films in this embodiment can form thin films without exposing the silicon substrate to the air, so that the thin films can be formed with less time than in Example 1. Furthermore, when a substrate disposed with a film is exposed at high temperature to the air by breaking the vacuum, a transformed layer is created at a part of the film surface. As a result, the thin film capacitors manufactured in the above-mentioned manner tend to show difference in properties. However, the apparatus of forming thin films in this embodiment can form thin films without exposing the silicon substrate to the air, thereby enabling reducing of the differences in the properties.
EXAMPLE 4
Another embodiment of this invention will be explained by referring to FIG. 4.
This embodiment differs from the embodiment of FIG. 3 in that a connection part 10 is disposed at the substrate transfer passage 8, and a connection part 6 is disposed at an exhaust pipe 2c of between the rf magnetron sputtering device 3 and a turbo molecular pump 5. The substrate transfer passage 8 having the switch valve 7 is connected with the plasma chemical vapor deposition device 4, and the substrate transfer system 9 is connected to the plasma chemical vapor deposition device 4. This configuration has the advantage of cutting off the rf magnetron sputtering device at the connection parts 6 and 10, and exchanging it with other physical vapor deposition devices.
In addition, the connection parts 6 and 10 may be disposed at an exhaust pipe 2b of between the exhaust switching means 1 and the plasma chemical vapor deposition device 4. Furthermore, the device to be exchanged may be other chemical vapor deposition devices.
Also, the embodiments of this invention used the rf sputtering device as the physical vapor deposition device, but the same effects can be obtained by using a vacuum vapor deposition device or an ion plating device. Furthermore, the plasma chemical vapor deposition device was used as the chemical vapor deposition device, but the same effects can be obtained by using a thermochemical vapor deposition device. In addition, the substrate is not limited to the silicon substrate which was used here, but other semiconductor substrates, for example, a conductive substrate such as metal, glass, an insulating substrate such as ceramics, gallium arsenide may be used as well to obtain the same effects. Also, the thin films formed are not limited to the dielectric thin films of platinum and Ba 1-x Sr x TiO 3 described here, but other conductive thin films, other dielectric thin films, semiconductor thin films, magnetic thin films, and superconductive thin films may be used to obtain the same effects. Furthermore, it was explained in the above-mentioned embodiments by using one rf sputtering device and one plasma chemical vapor deposition device, but the configuration is not limited to this, and the number can be increased, if necessary. Also, the substrate transfer system may be connected to the physical vapor deposition device instead of the chemical vapor deposition device. In addition, as for the exhaust means, an oil diffusion pump or a dry pump may be used instead of the turbo molecular pump which is one kind of mechanical pump. The switch valve disposed at the substrate transfer passage may be two or more, if necessary.
The invention may be embodied in other forms without departing from the spirit or essential characteristics thereof. The embodiments disclosed in this application are to be considered in all respects as illustrative and not as restrictive. The scope of the invention is indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are intended to be embraced therein.
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An apparatus of forming thin films, which is small and requires a short thin-film formation time, is provided which comprises at least one physical vapor deposition device and at least one chemical vapor deposition device, wherein said physical vapor deposition device and said chemical vapor deposition device are provided with an exhaust pipe respectively for connection with a common exhaust means and an exhaust switching means. A method of forming thin films using this apparatus is also provided. According to the configuration in which the exhaust switching means is connected via exhaust pipes to the physical vapor deposition device, to the chemical vapor deposition device, and to the exhaust means, this apparatus can be accomplished in a small size which has at least two chambers and one exhaust means. In this way, thin films can be formed in a short thin-film formation time with a small apparatus, since vapor of a starting material which is led in at the time of chemical vapor deposition does not enter the physical vapor deposition device.
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RELATED APPLICATIONS
[0001] This application is a divisional of U.S. Ser. No. 09/223,545, which was filed on Dec. 30, 1998, which claims priority to U.S. Provisional Application No. 60/070,166, filed Dec. 31, 1997. The entire teachings of the above applications are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] Metallized polymer sheeting is now commonly employed as a substitute for decorative chrome parts, especially in the automotive industry. Typically, such metallized polymer sheeting includes a layer of metal disposed between two polymer sheets.
[0003] There are several problems, however, with many types of known metallized polymer sheets. For example, laminates typically include an electrically continuous metal layer sandwiched between two polymer sheets. Such materials are often subject to delamination consequent to poor binding between the metal layer and the polymer layers on either side. Further, corrosion of the metal layer, which is usually aluminum can spread between the polymer layers, thereby causing significant diminution in appearance.
[0004] One attempt to reduce the likelihood of delamination and loss of appearance resulting from corrosion of the metal layer has been to form a discontinuous metal layer on a polymer basecoat, such as a resinous urethane. A monomer top-coat, such as a solvent-based aliphatic urethane, is then deposited on the discontinuous metal layer, and subsequently polymerized to encapsulate metal islands of the discontinuous metal layer and to bond them to the polymer basecoat.
[0005] However, formations of metal islands on various types of polymers can be difficult. Also, bonding of a urethane top layer during polymerization to a polyurethane basecoat can be poor. One attempt to improve adhesion has been to etch the basecoat and discontinuous metal layer with a sodium hydroxide solution to remove residual metal between islands of the discontinuous metal layer. A limitation to this method is that etching can result in the formation of blackened areas in the metal layer, thereby detracting from the appearance of the resulting laminated part.
[0006] There are several other problems that can be associated with polymerizing a top layer in situ to form metallized polymeric sheeting. For example, polyurethanes, in particular, generally are not sufficiently hydrophobic to prevent weathering over extended periods of time and are easily attacked by sodium hydroxide and acids, such as nitric acid. Thicker layers of polyurethane top-coat are difficult to form because in situ polymerization can cause the resulting composite to appear irregular. In addition, evaporation of a solvent component during polymerization of urethanes can cause “popping” or bubbles to form, also diminishing the appearance of the finished product. Further, methods which employ deposition of a basecoat, such as a resinous urethane basecoat, require that the basecoat be applied to a substrate, from which the resulting metallized composite generally cannot be removed. Therefore, the utility of this method for forming various products, having different applications, is limited.
[0007] Therefore, a need exists for a metallized composite and a method for forming such a metallized composite that overcomes or minimizes the above-referenced problems.
SUMMARY OF THE INVENTION
[0008] The present invention is directed to a metallized sheeting, such as a formable metallized plastic sheet, and a composite. The invention is also directed to a method for forming the sheeting and composite.
[0009] In one embodiment, the invention is a formable metallized plastic sheet which, upon molding, does not cause degradation of reflectivity of the metal sheet.
[0010] In another embodiment, metallized composite includes a first thermoplastic layer and a discontinuous layer on the first layer. The discontinuous layer is formed of discrete islands of metal in an adhesive. A second thermoplastic layer is disposed over the discontinuous layer, whereby the discontinuous layer is between said first and second thermoplastic layers.
[0011] In still another embodiment, the metallized sheeting includes a continuous thermoplastic sheet and at least one discontinuous layer of metal within said thermoplastic sheet.
[0012] The method includes depositing a metal on a first thermoplastic layer to form a discontinuous layer of the metal. A second thermoplastic layer is laminated onto the discontinuous layer.
[0013] The present invention has several advantages. For example, neither thermoplastic layer of the composite is polymerized in situ. Rather, the thermoplastic layers are laminated together to sandwich the discontinuous layer of metal islands in an adhesive bedding. Consequently, a wider variety of polymers can be employed to form the composite, thereby enabling greater opportunity for improving specific qualities of the composite and for tailoring construction of the composite for specific uses. For example, the choice of polymerized web materials can be selected for improved formation of discrete metal islands, such as by combining a particular metal with a polymer web that minimizes residual metal between metal islands. Alternatively, a polymer web can be selected that is preferably suitable for specific methods of metal deposition. By minimizing the amount of metal that remains between metal islands of the discontinuous layer, the need for etching can be significantly reduced or eliminated.
[0014] Further, because a top polymeric layer is not formed in situ, greater thicknesses can be employed without diminishing the appearance of the finished product, thereby improving resistance to environmental use conditions, such as weathering. In some instances, a plasma of unsaturated monomers, such as acrylates or methacrylates, may need to be polymerized on indium in vacuo; in such instances, the top layer would be added in another operation. Also, evaporation of solvents during polymerization is eliminated, thereby preventing “popping” and other potential processing problems. Moreover, a wider variety of methods of forming the composite can be employed, such as by depositing metal islands first on a thermoplastic drum surface, and subsequently transferring the metal islands to a first continuous thermoplastic web. A second thermoplastic web can then be applied over the discontinuous layer to form the composite. In other embodiments, the first and second thermoplastic webs can be bonded to each other by melting, use of an adhesive, or by compression. All of these processing options provide potential sources for reducing the cost of production and increasing overall product quality and productivity.
[0015] Different polymers can be employed for the two thermoplastic sheets, thereby further broadening the utility of the composites of the invention. In addition, neither the first nor the second thermoplastic web is bound to a substrate. Consequently, composites of the invention can be made to be flexible. Specific applications of flexible reflectors or mirrors can include adjustable rear-view mirrors for use in automobiles and as substitutes for conventional chrome-plated metal parts. In another embodiment, the composites can be molded after formation without degradation of the reflectivity of the discontinuous metal layer. Molding, such as embossing, for example, can provide an inexpensive means for incorporating a logo into flexible patches, such as can be applied to apparel, footwear, etc., that have the appearance of being perfectly reflective.
[0016] Other uses include in-mold decoration, blow molding and thermoforming. In-mold decoration, for example, includes injection molding a thermoplastic behind the sheet of composite to enable formation complex plastic art, such as parts having a reflective, mirror-like surface. The injection molding resin should be compatible with the first layer (the layer that will contact the molten injection molding resin). Preferably, the composition of the injection molding resin and the composition of the first layer of the composite will be the same; for example, injection molding a thermoplastic polyolefin (TPO) onto a composite which has as its first layer (facing the polymer melt) a TPO. Alternatively, the first thermoplastic layer and the injection molding resin should be compatible in the melt stage. An example of such a combination is a thermoplastic sheet of polycarbonate and an injection molding resin of polycarbonate-ABS blend.
[0017] Blow molding is similar to injection molding except that the molding resin is melted, extruded through a die and then blown with air or gas pressure against the walls of a mold cavity. In this case, a sheet of composite would be inserted into the mold and then the resin would be injected behind it.
[0018] In a thermoforming operation, the sheet is heated to soften it and then pushed into a cavity of a particular shape by a hot die surface. Vacuum forming is a similar process that also incorporates a vacuum to draw the softened sheet into the mold cavity as die pressure is applied to the opposite face.
BRIEF DESCRIPTION OF THE DRAWINGS
[0019] [0019]FIG. 1 is a cross-section of one embodiment of the composite of the invention, wherein first and second thermoplastic layers are bound together by an adhesive.
[0020] [0020]FIG. 2 is a cross-section of another embodiment of the composite of the invention, wherein a continuous thermoplastic layer encapsulates a discontinuous layer of metal.
[0021] [0021]FIG. 3 is a schematic representation of one embodiment of apparatus suitable for forming a composite of the invention.
[0022] [0022]FIG. 4 is a schematic representation of an alternate apparatus for forming a composite of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0023] The features and other details of the apparatus and method of the invention will now be more particularly described with reference to the accompanying drawings and pointed out in the claims. It will be understood that the particular embodiments of the invention are shown by way of illustration and not as limitations of the invention. The principal features of this invention can be employed in various embodiments without departing from the scope of the invention. All parts and percentages are by weight unless otherwise specified.
[0024] The invention is directed to a formable metallized plastic sheet and a method for forming the metallized plastic sheet. The term “formable,” as defined herein, includes, inter alia, suitability for in-mold decoration, blow molding, thermoforming, vacuum forming, etc. The formable metallized plastic sheet, upon molding, does not cause degradation of reflectivity of the metal sheet.
[0025] In one embodiment, shown in FIG. 1, metallized composite 10 includes first thermoplastic layer 12 . Discontinuous layer 14 is on first thermoplastic layer 12 and includes first side 16 and second side 18 . Discontinuous layer includes discrete islands of metal 20 and adhesive 22 . Second thermoplastic layer 24 is on discontinuous layer 14 , whereby discontinuous layer 14 is between the first and second thermoplastic layers. Discontinuous layer 14 preferably includes discrete specular islands of metal. Suitable metals, as defined herein, are those that can be deposited, or formed, on a suitable thermoplastic polymer. Examples of suitable metals include indium, zinc, tin, gallium, aluminum, cadmium, copper, nickel, cobalt, chromium, iron, gold, platinum, palladium, rhodium, etc. Preferably, the metal is indium. Also, preferably, discontinuous layer 14 is reflective; most preferably, discontinuous layer 14 has a mirror or mirror-like appearance. Optionally, discontinuous layer 14 can include specular islands of metal alloy. Examples of suitable alloys include stainless steel, nichrome, etc.
[0026] Examples of suitable adhesives of discontinuous layer 14 include at least one compound selected from the group consisting of styrene-butadiene copolymers, ethylene vinyl acetates, polyesters, polyamides, epoxies, acrylic pressure-sensitive adhesives, silicone pressure-sensitive adhesives, polyurethanes and isocyanate-cured polymers. The adhesive can be a thermally-activated adhesive.
[0027] In one specific embodiment, the adhesive includes two components. Preferred embodiments of adhesives that include at least two components include combinations of polyester, polychloroprene or polyurethane with isocyanate-functional crosslinkers, and a combination of water-based polyurethane dispersion with aziridine or with a water-dispersable isocyanate crosslinker. In another specific embodiment, the adhesive can be suitable for curing by exposure to ultraviolet light. An example of such an adhesive is ultraviolet light-curable pressure-sensitive adhesive.
[0028] First and second thermoplastic layers include at least one suitable thermoplastic polymer. These layers can also be formed of the same material, or they can be formed of different materials. A suitable thermoplastic polymer, as defined herein, is a thermoplastic polymer that effectively shields discontinuous layer 14 from environmental factors, such as weathering, humidity, and acidic or basic solutions encountered during ordinary intended final use of the composite. Examples of acidic and basic solutions include mild solutions of nitric acid or caustic. Specific examples of suitable thermoplastic polymers include, inter alia, polyethylene, polystyrene, polycarbonate, polyethylene terephthalate (PET), glycol-modified polyethylene terephthalate (PETG), polyvinylchloride (PVC), thermoplastic polyurethane (TPU), acrylonitrile butadiene styrene (ABS), polymethylmethacrylate, polypropylene, polyvinyl fluoride (PVF), TPO, polyethylene napthalate (PEN), polymethylpentene, polyimide, polyetherimide, polether ether ketone (PEEK), polysulfone, polyether sulfone, ethylene chlorotrifluoroethylene, cellulose acetate, cellulose acetate butyrate, plasticized polyvinyl chloride, polyester polycarbonate blends, ionomers (Surtyn), and co-extruded films or sheets of these thermoplastics, etc. The thermoplastic polymers can be elastomeric thermoplastics, and are commonly referred to as thermoplastic elastomers or TPE's. Examples include polyurethane (TPU), styrene-butadiene-styrene (SBS), styrene-ethylene-butadiene-styrene (SEEBS). Examples of opaque or translucent thermoplatics include polypropylene, polyamide, polyphenylene sulfide (PPS), styrene-maleic anhydride, polytetrafluoroethylene (PTFE), polycarbonate-ABS blends, polycarbonate polyester blends, modified polyphenylene oxide (PPO).
[0029] In one embodiment, first thermoplastic layer 12 predominantly includes a first thermoplastic polymer and a second thermoplastic layer 24 predominantly includes a second thermoplastic polymer. Examples of suitable combinations of first and second thermoplastic polymers are combinations of polyvinylidene difluoride (PVDF) and acrylonitrile butadiene styrene (ABS), PVDF/TPO, TPU/PVC, etc.
[0030] First thermoplastic layer 12 or second thermoplastic layer 24 , or both, can be clear or tinted. Examples of suitable components for tinting continuous thermoplastic layers 12 and or 24 include suitable organic or inorganic dyes or pigments, etc. As an alternative to tinting the thermoplastic layer, the adhesive can be tinted. This has the advantage of being cheaper than adding colorant to plastic sheeting; moreover, the plastic sheeting can screen the colorant for exposure to ultraviolet light (UV), thus making it possible to use nonlight-fast colorants. In another embodiment, first thermoplastic layer 12 or second thermoplastic layer 24 can be opaque. Examples of suitable components that can cause opacity include carbon black, iron oxide, titanium dioxide, etc.
[0031] Metallized composite 10 can be embossed, such as by a conventional method, including, for example, heat pressing. As another option, metallized composite 10 can be formed, for example, to form a part that is to exhibit a translucence that is a multiple of the translucence of a single-ply of metallized composite. As another alternative, metallized composite 10 can be supported by a substrate, whereby metallized composite 10 is in contact with the substrate. Examples of suitable substrates include thermoplastic polyurethane, polyvinylchloride, glycol modified polyethylene, thermoplastic polyolefin, fiber reinforced nylon, fiberglass, aluminum, and metal alloys, such as steel, etc.
[0032] In another embodiment, metallized composite 26 , shown in FIG. 2, includes continuous thermoplastic sheet 28 that encapsulates discontinuous layer 30 of metal. The metal, or metals of discontinuous layer 30 , and suitable thermoplastic polymers of continuous thermoplastic sheet 28 are the same as those described above with reference to FIG. 1.
[0033] As with the embodiments set forth above and shown in FIG. 1, metallized composite 26 of FIG. 2 can include one or more thermoplastic layers that are clear, tinted or opaque. Also, elastomeric thermoplastic composite can be supported by a substrate, formed or embossed. In one embodiment, discontinuous layer 30 substantially partitions thermoplastic sheet 28 , whereby thermoplastic sheet 28 predominantly includes a first thermoplastic polymer at first side 32 of discontinuous layer 30 , and predominantly includes a second thermoplastic polymer at second side 34 of discontinuous layer 30 .
[0034] The method for forming a metallized composite of the invention generally includes depositing a metal on a first thermoplastic layer to form a discontinuous layer of the metal. A second thermoplastic layer is laminated onto the discontinuous layer. Suitable methods for deposition of metal on the first thermoplastic layer includes electron evaporation, sputtering, ion plating, induction heating, thermal evaporation, transfer of a preformed metal layer from a separate substrate, etc.
[0035] Optionally, the method includes bonding the first thermoplastic layer to the second elastomeric thermoplastic layer. Examples of suitable methods for bonding the thermoplastic layers include heating, to thereby cause the layers to melt combined and form a single, continuous thermoplastic layer. Alternatively, the layers can be bonded by heating without melting, pressing the layers together, or applying a suitable adhesive to the first and/or second thermoplastic layer before laminating the layers together.
[0036] In embodiments where an adhesive is employed that is curable by ultraviolet light, the method includes exposing the thermoplastic composite to ultraviolet light to thereby cure the adhesive. Alternatively, a UV-curable adhesive applied to one thermoplastic layer can be exposed to UV light and then laminated to a second thermoplastic layer.
[0037] Conventional methods can be employed to conduct other optional steps, such as molding, folding, and/or embossing the metallized composite. In one embodiment, apparatus 40 , shown in FIG. 3, is employed to conduct a method of the invention. Therein, first thermoplastic layer 42 is drawn from roll 44 across deposition guns 46 by reel 48 . Deposition guns 44 deposit a suitable metal, such as indium on first thermoplastic layer 42 . Deposited metal forms discrete islands on first thermoplastic layer 42 , which then passes across roller 50 . Preferably, roller 50 cools first thermoplastic web 42 . Optionally, first elastomeric thermoplastic web 42 is coated with an adhesive deposited prior to or after deposition of specular islands of metal.
[0038] Second elastomeric thermoplastic layer 52 is drawn from roll 54 by reel 48 . Optionally, second thermoplastic layer 52 is coated with an adhesive. First and second thermoplastic layers 42 , 52 meet at rollers 56 . In one embodiment, rollers 56 are heated. Preferably, in embodiments where rollers 56 are heated, they are heated to a temperature of about 300° F. First and second elastomeric thermoplastic layers 42 , 52 become bonded to each other while passing through rollers 56 , to thereby form a thermoplastic composite 58 of the invention. Thermoplastic composite 58 is drawn across roller 60 and then collected on reel 48 .
[0039] In another embodiment, apparatus 70 , shown in FIG. 4, is employed to conduct a method of the invention. In this embodiment, drum 72 includes a suitable thermoplastic coating 74 . A suitable thermoplastic coating is one that will enable formation of discrete metal islands thereon by deposition, such as by electron beam evaporation, and which is suitable for transfer of metal islands to a first thermoplastic layer. An example of a suitable thermoplastic coating of drum is JPS 1880 Glossy 2® sheet stock material (urethane).
[0040] Drum 72 rotates, whereby metal plumes formed by deposition guns 76 cause deposition of the metal onto thermoplastic coating 74 of drum 72 . As drum 72 rotates, discontinuous layer 78 of metal islands forms on thermoplastic coating 74 of drum 72 .
[0041] First thermoplastic layer 80 is drawn from drum 82 by take-up reel 84 . During conveyance from drum 82 to take-up reel 84 , first thermoplastic layer 80 passes between rollers 86 and drum 72 . Rollers 86 press first thermoplastic layer 80 against discontinuous layer 78 on drum 72 , thereby transferring discontinuous layer 78 to thermoplastic layer 80 . In one embodiment, rollers 86 are heated.
[0042] Second thermoplastic layer 88 is drawn from drum 90 by take-up reel 84 . Optionally, an adhesive is deposited on second thermoplastic layer 88 . First and second thermoplastic layers 80 , 88 meet at rollers 92 . Rollers 92 cause contact between first and second thermoplastic layers 80 , 88 . Preferably, rollers 92 are heated. Contact between first and second thermoplastic layers 80 , 88 at rollers 92 causes formation of a thermoplastic composite of the invention. The thermoplastic composite is subsequently collected on take-up reel 84 .
[0043] In another embodiment, indium is vacuum deposited on a first thermoplastic layer. The metallized sheet is removed from the vacuum chamber and laminated to a second thermoplastic layer or to the second thermoplastic layer with adhesive pre-applied, using conventional laminating methods employed in the coating/laminating industry. Alternatively, the deposited indium layer is coated in vacuo with a thin plasma-polymerized coating to protect the metallization.
[0044] In still another embodiment, an interleaf of plastic film, usually polyethylene or polyethylene terephthalate is wound with the indium metallization to protect the metal layer as it is rewound. It is subsequently stripped out as the metallized sheeting is coated or laminated.
[0045] In a further embodiment, the metallized sheeting is laminated to a film adhesive. A film adhesive consists of a layer of adhesive between two release liners. One liner at a time can be removed and the adhesive laminated to one thermoplastic sheeting. The second liner can then be removed and the laminate is adhered to the second thermoplastic layer.
[0046] The performance of the metallized composite can be further improved by overcoating or overlaminating additional layers of polymerized plastics or films over the composite to further improve abrasion resistance, chemical resistance, weathering resistance, etc. For example, a UV-curable hardcoat can be applied to the metallized composite and then cure the coating by exposure to high-intensity UV light.
[0047] The invention will now be further described by the following examples, which are not intended to be limiting in any way. All parts and percentages are by weight unless otherwise specified.
[0048] Exemplification
EXAMPLE 1
[0049] A sample of A-4100® clear urethane sheet stock, made by Deerfield Urethane, A Bayer Company, South Deerfield, Mass., was metallized in a 72″ metallizer (Part #EJWIN403MM30, made by Kurt J. Lesker Co., Inc., Clairton, Pa.). About 300 Å of indium was deposited, through electron beam deposition, onto the surface of the urethane. A second sheet of A-4100® clear urethane sheet stock was removed from its polyester released liner backing and was gently pressed onto the surface of the indium. Special attention was given to removing air bubbles that might expand in the convection process. A heat gun was then utilized to heat the two samples. The conventional heat gun was set to a temperature of 400° F. and was held at a distance of approximately 4 inches from target. When exposed to the heat, the two identical sheets of material immediately showed signs of melting as the two materials appeared to be fused together. The indium layer slightly discolored during the convection heating. Samples of the same type were repeatedly run to attempt to maximize appearance. Finally, a convection oven set at a temperature of 300° F. was used to melt the materials together over a 4-5 minute duration. Slight iridescence persisted with the fusing process. Since the initial trials with the A-4100® clear urethane sheet stock, it was been determined that the metallized unprotected sheet appeared to have a finite shelf life, whereafter the sample will discolor, and eventually turn white with thermal application of the top film. In practice, it should be the intent of the designer to have the materials mated as soon as possible to prevent this occurrence.
EXAMPLE 2
[0050] A sample of JPS 1880 Glossy 2® sheetstock material (urethane) was metallized in a 72″ metallizer (Part #EJWIN403MM30, made by Kurt J. Lesker Co., Inc., Clairton, Pa.). About 300 Å of indium was deposited, through electron beam deposition, onto the surface of the urethane. A sample of the A-4100® clear urethane sheet stock, with the polyester release liner backing removed, was then gently applied to the surface of the indium. The sandwiched samples were then inserted into a 300° F. convection oven for a duration of 2 minutes. The samples were then removed from the oven and allowed to cool to the touch. The samples were then manually pulled apart by starting a separation at the edge. At this point it was noted that the indium had been effectively transferred to the A-4100® clear urethane sheet stock substrate. The indium surface maintained its superior reflective properties with no distortion evident. The sample of the JPS material was discarded, while a second sheet of A-4100® clear urethane sheet stock was thermally adhered to the first using the same process outlined above.
EXAMPLE 3
[0051] Additional work was performed using an adhesive technique for application of the protective film. Two samples of sheet, JPS 1880 Glossy 2® sheet stock and 30 mil E-grade double polished PVC film were used. Both of the sheets generally had a transparent appearance, but the E-grade double polished PVC film material had a slight blue tint due to the resin's inherent nature. They were metallized in a 72″ metallizer (Part #EJWIN403MM30, made by Kurt J. Lesker Co., Inc., Clairton, Pa.). About 300 Å of indium was deposited, through electron beam deposition, onto the surface of the urethane. After metallization, an adhesive-backed film of PVC, KPMF® black, supplied through Kay Automotive Graphics, Inc. from KPMF, Inc., Wells, Okla., was carefully applied to the indium layers of each sample. The sample, when viewed through the JPS 1880 Glossy 2® sheet stock material or E-grade double polished PVC film material, exhibited a clear mirror-like appearance.
EXAMPLE 4
[0052] A standard vacuum web metallizer was used to vacuum metallize continuous rolls of film with indium metal. Indium wire (0.070″) from Arconium Corporation was continuously fed to heated ceramic boats. Highly reflective indium depositions were achieved using web speeds of 50 to 300 ft/minute.
[0053] 1,100 linear feet of 40″ wide 1-mil PET film was vacuum metallized at web speeds from 30 to 50-ft/minute. The indium wire feed rate averaged 28″/minute. This highly reflective, vacuum metallized film was then adhesively laminated to 6.5 mil PET film in a standard web coater-laminator to create a laminate with the indium layer between two PET films. The adhesive used was National Starch 3918 laminating adhesive modified with carbon black filler to provide an opaque backing to the indium layer. The adhesive was applied to the uncoated polyester film using a 165 quad gravure cylinder; web speed was 50 feet/minute. The adhesive coated film was then laminated in-line to the indium-coated film at a nip temperature of 130° F.
[0054] Samples of this laminate were then tested for lamination strength using an Instron tester. Initial bond values (obtained within 15 minutes of lamination) were 1.8-2.3 lbs./inch. Samples aged at room temperature for three days had lamination strengths of 2.4-2.5 lbs./inch.
[0055] Equivalents
[0056] Those skilled in the art will recognize, or be able to ascertain using no more than routine experimentation, many equivalents to the specific embodiments of the invention described specifically herein. Such equivalents are intended to be encompassed in the scope of the claims.
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A metallized composite includes a thermoplastic sheet and at least one discontinuous layer of metal within the thermoplastic sheet. The discontinuous metal layer can be disposed between two thermoplastic layers that are bound together, such as by melting the layers together, pressing, or by use of an adhesive. The metallized composites of the invention can be employed as reflective surfaces, such as are used as mirrors or substitutes for chrome trim on automobiles. A particularly preferred metal as a component of the discontinuous layer of the composite is indium.
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RELATED APPLICATIONS
[0001] The present application is based on, and claims priority from, Provisional Application No. 60/886,529, filed Jan. 25, 2007, the disclosure of which is hereby incorporated by reference herein in its entirety.
BACKGROUND OF THE INVENTION
[0002] The present invention generally relates to a method and device that aids in vehicle restoration, and more particularly to a reinforcement plate for a door handle of a vehicle.
[0003] Restoration of vintage and classic automobiles is a common hobby for many car enthusiasts. Restoration may involve purchasing a classic or vintage automobile, obtaining the necessary parts to restore the vehicle, performing the work necessary to assemble the parts, etc. In many cases, finding the parts necessary to adequately restore a vehicle in and of itself is a difficult task.
[0004] Vehicle doors of classic or vintage automobiles often require restoration. The vehicle doors of older cars are often manufactured from a single sheet of metal of a relatively small thickness. The vehicle door includes a door handle which is received and secured through openings extending through the sheet metal. Over time, repetitive pushing and pulling on the door handle may weaken the metal surrounding the door handle. Disadvantageously, the metal surrounding the door handle may eventually dimple, buckle or bubble, which may detract from the overall appearance of the restored vehicle.
[0005] Accordingly, it is desirable to provide a reinforced vehicle door handle which is strengthened in the area of the vehicle door surrounding the door handle and is of a simple design that is easy to manufacture.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] The various features and advantages of this invention will become apparent to those skilled in the art from the following detailed description. The drawings that accompany the detailed description can be briefly described as follows:
[0007] FIG. 1 illustrates a vehicle door having an example door handle reinforcement plate;
[0008] FIG. 2 is a schematic side view of the vehicle door illustrated in FIG. 1 ;
[0009] FIG. 3 illustrates the example door handle reinforcement plate;
[0010] FIG. 4 is a front view of the example door handle reinforcement plate illustrated in FIG. 3 ; and
[0011] FIG. 5 illustrates a method for reinforcing a vehicle door.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0012] FIG. 1 illustrates a vehicle door 10 having a door handle 12 . The vehicle door 10 includes an outer surface 14 and an inner surface 16 . The outer surface 14 faces the exterior of a vehicle, while the inner surface 16 faces an interior compartment of a vehicle.
[0013] A reinforcement plate 18 is positioned at the inner surface 16 of the vehicle door 10 directly adjacent to the door handle 12 (See FIG. 2 ). A latching mechanism 20 of the door handle 12 is received through the reinforcement plate 18 . A plurality of fasteners 22 attach the reinforcement plate 18 to the door handle 12 and tightly secure the reinforcement plate 18 and the door handle 12 to the vehicle door 10 . The reinforcement plate 18 provides increased structural integrity of the door handle 12 relative to the vehicle door 10 and prevents the dimpling or buckling of the area of the vehicle door 10 which surrounds the door handle 12 . The example vehicle door 10 , the example door handle 12 and the example reinforcement plate 18 illustrated and described herein are not limited to any particular size and shape and may vary depending upon the model of vehicle these components accompany.
[0014] FIG. 3 illustrates the example reinforcement plate 18 . In the example shown and discussed herein, only a left handed reinforcement plate 18 for the vehicle doors 10 of the left side of a vehicle is shown for clarity. Those skilled in the art will understand that a right handed reinforcement plate for the vehicle doors of the right side of the vehicle could be a mirror image of the left handed reinforcement plate 18 illustrated and described herein.
[0015] The reinforcement plate 18 includes a body portion 24 and a pair of flange portions 26 . The body portion 24 extends between the flange portions 26 . The reinforcement plate 18 defines a length L and a width W. The body portion 24 is disposed along a substantial portion of the width W of the reinforcement plate 18 and extends along the entire length L of the reinforcement plate 18 . It should be understood that the actual length, width and thickness of the reinforcement plate will vary depending upon design specific parameters, including but not limited to, the model of vehicle and the type of door handle included with the vehicle door.
[0016] The body portion 24 of the reinforcement plate 18 includes a latch opening 28 and at least one fastener opening 30 . In one example, the body portion 24 includes two fastener openings 30 . Although two fastener openings 30 are shown in FIG. 3 , it should be understood that the actual number, size and shape of fastener openings 30 will depend upon the type of door handle 12 included with the vehicle door 10 . The latch opening 28 receives the latch mechanism 20 of the door handle 12 where mounted to the vehicle door 10 . In one example, the shape of the latch opening 28 directly corresponds to the shape of the latch mechanism 20 . A worker of ordinary skill in the art having the benefit of this disclosure would be able to design the latch opening 28 to receive any latch mechanism 20 of any door handle 12 .
[0017] The flange portions 26 of the reinforcement plate 18 extend transversely from the body portion 24 . In one example, the flange portions 26 extend at an angle Y of 45 degrees relative to an axis A defined by the body portion 24 (see FIG. 4 ). In another example, the flange portions 26 extend at an angle Y of 27.5 degrees relative to the axis A defined by the body portion 24 . In yet another example, the flange portions 26 are angled at angle Y relative to the body portion 24 such that the body portion 24 contours the natural body line of the vehicle door 10 . It should be understood that the actual angle Y of the flange portions 26 relative to the axis A of the body portion 24 will vary depending upon the design of the vehicle door and the door handle. The flange portions 26 provide strength and integrity to the reinforcement plate 18 when the reinforcement plate 18 is attached to the door handle 12 .
[0018] FIG. 5 , with continuing reference to FIGS. 1-4 , illustrates an example method 100 for reinforcing a door handle 12 of a vehicle door 10 . At step block 102 , an appropriate reinforcement plate 18 is selected based upon the model of vehicle and the type of door handle 12 included on the vehicle door 10 of the vehicle. For example, where the vehicle being restored is a 1970 Dodge Dart, an appropriate reinforcement plate 18 having a latch opening 28 and fastener openings 30 which correspond to the door handle 12 of the 1970 Dodge Dart is selected.
[0019] Next, at step block 104 , the door handle 12 of the vehicle door 10 is at least partially inserted into openings of the vehicle door 10 to position the door handle 12 against the outer surface 14 of the vehicle door 10 . Where required, such as where an entire new vehicle door 10 is necessary, holes may be drilled through the vehicle door 10 to receive the door handle 12 .
[0020] The reinforcement plate 18 is positioned at the inner surface 16 of the vehicle door 10 at step block 106 . In one example, the reinforcement plate 18 is positioned such that the flange portions 26 extend in a direction toward the inner compartment of the vehicle. The latch mechanism 20 of the door handle 12 is extended through the latch opening 28 of the reinforcement plate 18 and the reinforcement plate 18 is pushed directly against the inner surface 16 of the vehicle door 10 such that it is directly adjacent to the door handle 12 . At step block 108 , the fastener openings 30 of the reinforcement plate 18 are aligned with the existing fastener openings of the door handle 12 .
[0021] Finally, at step block 110 , the fasteners 22 are inserted into the fastener openings 30 at the inner surface 16 in a direction towards the outer surface 14 of the vehicle door 10 . The fasteners 22 are torqued in a known manner to securely tighten the reinforcement plate 18 relative to the vehicle door 10 and to securely affix the door handle 12 to the outer surface 14 of the vehicle door 10 . The reinforcement plate 18 provides structural integrity to the door handle 12 and the vehicle door 10 as the door handle 12 is pushed and pulled to open and close the vehicle door 10 . That is, the reinforcement plate 18 distributes the forces that result from pushing and pulling on the door handle 12 over a greater area of the vehicle door 10 to increase the stiffness and strength of the mounting of the door handle 12 .
[0022] The foregoing description shall be interpreted as illustrative and not in any limiting sense. A worker of ordinary skill in the art would recognize that certain modifications would come within the scope of this invention. For that reason, the following claim should be studied to determine the true scope and content of this invention.
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A door handle reinforcement plate that is positioned on the inner surface of a vehicle door. The plate is mounted using the fasteners of the existing door handle. The door handle reinforcement plate adds strength and rigidity to the vehicle door to prevent the vehicle door from flexing or distorting in an undesirable fashion.
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FIELD OF INVENTION
This invention relates generally to braking systems and more particularly to a disc brake system having a unitary support for the brake pads.
BACKGROUND OF THE INVENTION
In a typical disc brake, a rotor secured to one of the wheels of an automotive vehicle rotates between a pair of brake pads. The braking load, when the brake pads engage the rotor, is reacted against abutments or rails at opposite ends of each pad. The pad ends push against one rail or the other depending on the direction of rotation. This produces a couple, forcing the leading edges of the brake pads together, giving rise to instability and noise.
SUMMARY OF THE INVENTION
In accordance with the present invention, each disc brake pad has one end portion connected to and partially restrained by a support, and a second free end portion which is cantilevered from the first end portion. The general operation of this type of braking arrangement is disclosed in co-pending application Ser. No. 08/931,605, filed Sep. 16, 1997 and which is assigned to the same assignee as that of the instant application and which is incorporated herein by reference.
More particularly, the disc brake assembly includes an axially rotatable brake rotor disposed between two brake pads. Each brake pad has a leading end portion and a trailing end portion. The leading end portions of the brake pads engage and are circumferentially restrained by a support. The trailing end portions are substantially cantilevered from the leading end portions. During forward braking, the pads pull rather than push against the support which provides a reaction abutment. A more stable and quieter braking action is the result.
Preferably, the support for the brake pads includes a rail in the form of a reaction block having a pair of slots or reaction surfaces, with the leading end portions of the brake pads having fingers respectively restrained within the slots. In normal forward wheel rotation, as soon as the brake is applied, the brake pads are pulled circumferentially by the friction forces which are reacted by the reaction block, effectively acting as a pinned joint at the interface between the reaction block and the fingers. The brake pads engage the rotor beyond this interface rather than before it. Therefore, the brake pads are dragged or pulled over the rotor rather than pushed, providing much less potential for vibration and noise. Both forward and reverse wheel rotation braking forces are reacted by the same reaction block. Since no trailing brake pad reaction block is required, unsprung mass is reduced. Less raw material is used, thereby lowering material costs. The associated vibrational propensities of a trailing brake pad restraint are eliminated. Brake pad cooling is improved because potential airflow is increased.
The undesirable reaction force couple present in prior constructions which forces the leading edges of the brake pads together is most effectively balanced or stabilized if the reaction surfaces of the slots engaged by the fingers of the brake pads are machined at an angle or in an arc rather than perpendicular to the brake pads. If machined at an angle, the reaction surface will provide a constant countering torque throughout the life of the brake pad. However, as the pad wears, the balancing effect diminishes. To more nearly balance out the changing couple as the pad wears, the reaction surface is machined in an arc. This provides a relatively large balancing couple when the pads are new, which dwindles as the pad wears thinner. By selecting the appropriate angle or arc, the reaction surface will produce as much counterbalancing as needed to produce a more stabile braking system with reduced vibration and propensity to squeal.
One object of this invention is to provide a disc brake assembly having the foregoing features and capabilities.
Another object of the invention is to provide a disc brake assembly which is more stable and quiet, is composed of a relatively few simple parts, is rugged and durable in use, and can be readily manufactured and assembled.
These and other objects, features and advantages of the invention will become more apparent as the following description proceeds, especially when considered with the accompanying drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of an automobile equipped with a braking system constructed in accordance with the invention.
FIG. 2 is a fragmentary perspective view of the braking system.
FIG. 3 is an exploded, fragmentary perspective view of the braking system.
FIG. 4 is a fragmentary top view showing the brake pads on opposite sides of the rotor.
FIG. 5 is a view with parts in elevation and parts in section taken on the line 5--5 in FIG. 4.
FIG. 6 is a fragmentary side elevational view of the braking system taken in the direction of the arrow 6 in FIG. 2.
FIG. 7 is a view similar to FIG. 4, but shows a modification.
FIG. 8 is an elevational view of one of the brake pads in FIG. 7.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now more particularly to the drawings, there is shown in FIG. 1 an automobile 10 having a disc brake 12 constructed in accordance with the invention. In FIGS. 2 and 3, the disc brake 12 is shown to include a circular rotor 14 concentric with and secured to a wheel 16 (FIG. 1) of the automobile 10 for axial rotation therewith about axis 17, and a generally U-shaped caliper 18 having brake pads 20 and 22 on opposite sides of the outer peripheral portion 24 of the rotor.
As further seen in FIGS. 2 and 3, a steering knuckle 26 provides a base or support for the caliper 18. The caliper 18 embraces the peripheral portion 24 of the rotor and has jaws 28 and 30 on opposite sides thereof to which one or more brake pads may be spring clipped. The jaw 28 is provided with a hydraulic cylinder 32 for urging the brake pad 20, which may be spring clipped to it, against one face of the peripheral portion 24 of the rotor and by reaction, the pad 22 against the opposite face of the peripheral portion of the rotor. This much of the disc brake is of conventional construction, as more fully described in U.S. Pat. No. 4,944,371 which is incorporated herein in its entirety by reference.
Each of the brake pads 20 and 22 includes an elongated, arcuate, flat, planar backing plate 34 (FIG. 5) which has planar, parallel, laterally inner and outer surfaces. Each backing plate is parallel to the rotor, and a body 36 of frictional material is provided on the laterally inner surface thereof facing the peripheral portion 24 of the rotor. The arcuate backing plates 34 are parallel to one another and each extends in a circular arc along the outer peripheral portion 24 of the rotor and is centered on the axis 17 of the rotor.
In FIGS. 4 and 5, each of the brake pads 20 and 22 is shown to include opposite end portions 38 and 40. When the wheel 16 and rotor 14 are rotating counterclockwise in FIG. 5 (the forward direction), the end portion 38 is the leading end portion and the end portion 40 is the trailing end portion. The leading end portion 38 of the brake pad 20 has a radially outwardly extending finger 42 which is a flat, integral, coplanar extension of the backing plate of the brake pad 20. The leading end portion 38 of the brake pad 22 has a radially outwardly extending finger 44 which is a flat, coplanar, integral extension of the backing plate of the brake pad 22. Line 84 is a radius from the center 17 of rotation of the rotor 14 drawn through the center of finger 42. Although fingers 42 and 44 are shown extending outwardly parallel to line 84, they may be angled forwardly so that they extend outwardly parallel to line 78 (which also passes through the rotor axis 17), or parallel to any line passing through axis 17 between lines 78 and 84. Proper choice of finger orientation per these guide lines allows further reduction of radial instability.
As seen in FIGS. 2 and 3, a support including a rail in the form of a reaction block 50 is rigidly secured as by bolts 51 to the steering knuckle 26. Reaction block 50 has two laterally spaced-apart slots 52 and 54. As seen in FIGS. 4 and 5, the fingers 42 and 44 of the brake pads 20 and 22 extend into the respective slots 52 and 54. Each finger may be pinned in its slot or retained therein by a transverse pin extending through a hole 55 in the finger and bearing on the outer surface of the reaction block 50. The end 56 of each slot provides a reaction surface which is straight and flat, and forms an inclined acute angle θ to a line perpendicular to the central plane of the rotor 14 (FIG. 4). The end 58 of each slot provides a reaction surface which is straight and flat, and parallel to the reaction surface 56 and forms the same inclined acute angle θ to a line perpendicular to the central plane of the rotor 14. The ends 56 and 58 of each slot also form an acute angle with the planar surfaces of the associated backing plate. The reaction surfaces 56 of the slots 42 and 44 together define an included angle of less than 180°. The reaction surfaces 58 of the slots define the same included angle. The fingers 42 and 44 engage the reaction surfaces 56 on forward braking, whereas they engage the reaction surfaces 58 on rearward braking. The sides 60 and 62 of each slot are parallel to the plane of the finger therein and to the rotor 14.
The backing plates 34, at the leading end portions 38 of the brake pads, extend circumferentially from the fingers 42 and 44 and generally perpendicularly from the slots into which the fingers extend.
The distance between the reaction surfaces 56 and 58 of each of the slots 52 and 54 is slightly greater than the distance between the end edges 64 and 66 of the finger therein. The end edges 64 and 66 are flat and parallel to one another and parallel to the reaction surfaces 56 and 58. Thus, the end edges 64 have a flush engagement with the reaction surfaces 56 on forward braking, and the end edges 66 have a flush engagement with the reaction surfaces 58 on rearward braking.
The distance between the sides 60 and 62 of the slots 52 and 54 is greater than the distance between the flat parallel sides of the finger therein by an amount sufficient to allow the brake pads to be moved laterally inwardly and outwardly into and out of frictional contact with the opposite sides of the outer peripheral portion 24 of the rotor.
The trailing end portions 40 of the brake pads are free floating, that is, they are not connected to a reaction block or to any other abutment, nor do they engage any abutment of any kind which would resist rotation. Thus, other than any clipped connection to the caliper jaws or hydraulic cylinder, the brake pads are cantilevered from their leading end portions 38 via loose connection to the reaction block 50.
The point 74 in FIG. 5 is the approximate midpoint circumferentially and radially of the brake pad 20 and represents the point through which all resolved rotor drag forces act circumferentially along line 82. The line 78 is a radius from the center 17 of rotation of the rotor 14 to the midpoint 74. The line 82 drawn through the midpoint 74 perpendicular to radius 78 passes through the slot 52 and intersects the radius 84 at 83 which is the center of the finger 42 in slot 52. The same relationships apply to the brake pad 22.
This geometric relationship allows the brake pads to radially self-align on the rotor, thereby reducing radial instability of the pads and thereby reducing brake vibration and noise. Since the point of contact between the fingers 42,44 and the reaction block 50 is on or near line 82 as is resultant point 74 through which all rotor drag forces may be resolved in a circumferential direction, there is little or no radial force tending to radially push or pull the brake pad. This promotes stability and reduces brake noise.
As noted above, the reaction surfaces 56 and 58 of each of the slots 52 and 54 are formed at an acute angle θ to lines perpendicular to the central plane of the rotor 14. The angle θ is an angle selected to provide a constant torque to counterbalance the destabilizing couple which tends to pull the leading ends of the brake pads into the rotor and produce squeal. The angle θ is preferably determined by the formula ##EQU1## where T, as shown in FIG. 7, equals the thickness of the body 36 of friction material plus one-half the thickness of the backing plate 34, and L equals the distance between the midpoint 74 of the brake pad 20 or 22 and the intersection 83 of the radius 84 through the midpoint of the finger and the line 82 which is drawn perpendicular to the radius 78 through midpoint 74. The reaction surfaces of both slots are formed to the same angle.
When, during counterclockwise rotation of the wheel 16 in the forward direction as shown in FIG. 5, the brake is applied by actuation of the cylinder 32 to move the brake pads 20 and 22 laterally inwardly to cause the friction material 36 to make contact with the opposite sides of the peripheral portion 24 of the rotor, there is a reaction "pull" on the reaction block 50 through the flush engagement of the edges 64 of the fingers 42 and 44 with the reaction surfaces 56 of the slots 52 and 54. Since the trailing end portions 40 of the brake pads are free floating, virtually all braking forces are reacted through the leading end fingers such that there is no reaction push on the trailing end portions and virtually no resultant instability and squeal as in prior designs. The movement of the fingers along the inclined reaction surfaces 56 provides a constant countering torque opposing the forces pressing the leading edges of the pads together. Although the leading end fingers push against the reaction block during clockwise or rearward braking of the wheel, the trailing end portions are still not subjected to reaction forces as substantially all braking forces are reacted through the fingers during both forward and rearward braking of the wheel. On rearward braking, the edges 66 of the fingers have a flush engagement with the reaction surfaces 58 of the slots and in this case, the movement of the fingers along the inclined reaction surfaces 58 provides a constant countering torque opposing the forces pressing the trailing edges of the pads together.
FIGS. 7 and 8, show a modification in which the reaction surfaces 56A and 58A of the slots 52A and 54A are arcuate rather than straight. Each arc is on a radius R having a center spaced toward the trailing end of the disc brake pad, that is, in the direction of forward rotation, on the central plane of the rotor 14. Preferably, the radius R is equal to W divided by cos (90-θ), where W equals the distance between the central plane of the rotor and the outer surface 62A of the slot, and θ is the angle whose tangent equals T/L where T equals the thickness of the body 36A of friction material plus one-half the thickness of the backing plate 34A, and L equals the distance between the midpoint 74A circumferentially and radially of the disc brake pad and the intersection 83A of a radius 84A from the axis of rotor rotation through the center of the finger and a line 82A through the midpoint 74A of the disc brake pad perpendicular to a second radius 78A from the axis of rotation through the midpoint 74A. Both reaction surfaces 56A and 58A of each slot have the same radius. Note in FIG. 7, the angle θ is formed by a tangent to the arc of the reaction surface 58A at its laterally outer extremity and a line perpendicular to the plane of the rotor.
Preferably, in this construction the two end edges 64A and 66A of the fingers which are engageable with the reaction surfaces of the slots are convexly rounded as indicated.
Other than is as described, the construction of FIGS. 7 and 8 is like the construction of FIGS. 1-6.
As the body 36A of friction material wears, the offset producing the original couples forcing the leading ends of the pads inwardly against the rotor diminishes. The arcuately formed reaction surfaces 56A and 58A more nearly match this changing couple than the straight line reaction surfaces 56 and 58 of the embodiment of FIGS. 1-6. This arcuate form of the reaction surfaces provides a larger angle (and hence larger balancing couples) when the pads are new, dwindling as the pads become thinner.
While preferably fingers with convexly rounded end edges are most effective when used with the arcuate reaction surfaces in FIGS. 7 and 8, fingers with this configuration may also be used with the first described embodiment in which the reaction surfaces are straight rather than arcuate. Likewise, the finger construction in the first embodiment may, if desired, also be used with the arcuate reaction surface type construction in the second embodiment.
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A mounting assembly for a disc brake pad which has a first end portion provided with a finger engaged with a reaction surface in a slot of a reaction block to partially restrain the disc brake pad when it is applied against a rotor. The reaction surface is machined at an angle or in an arc to counterbalance the couple which forces the leading end of the disc brake pad inwardly against the rotor. The disc brake pad has a substantially unrestrained second end portion which is cantilevered from the first end portion. Braking forces are reacted virtually exclusively against the reaction block which is located externally of and separated from the disc brake caliper assembly.
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[0001] This is a divisional of U.S. application Ser. No. 10/134,780, filed Apr. 29, 2002, the entire disclosure of which is incorporated herein by reference.
FIELD OF THE INVENTION
[0002] The present invention relates generally to peer-to-peer protocols, and more particularly to security framework infrastructures for peer-to-peer protocols.
BACKGROUND OF THE INVENTION
[0003] Peer-to-peer (P2P) communication, and in fact all types of communication, depend on the possibility of establishing valid connections between selected entities. However, entities may have one or several addresses that may vary because the entities move in the network, because the topology changes, or because an address lease cannot be renewed. A classic architectural solution to this addressing problem is thus to assign to each entity a stable name, and to “resolve” this name to a current address when a connection is needed. This name to address translation must be very robust, and it must also allow for easy and fast updates.
[0004] To increase the likelihood that an entity's address may be found by those seeking to connect to it, many peer-to-peer protocols, including the Peer Name Resolution Protocol (PNRP), allow entities to publish their address through various mechanisms. Some protocols also allow a client to acquire knowledge of other entities' addresses through the processing of requests from others in the network. Indeed, it is this acquisition of address knowledge that enables successful operation of peer-to-peer networks. That is, the better the information about other peers in the network, the greater the likelihood that a search for a particular resource will converge.
[0005] However, without a robust security infrastructure underlying the peer-to-peer protocol, malicious entities can easily disrupt the ability for such peer-to-peer systems to converge. Such disruptions may be caused, for example, by an entity that engages in identity theft. In such an identity theft attack on the peer-to-peer network, a malicious node publishes address information for identifications (IDs) with which it does not have an authorized relationship, i.e. it is neither the owner nor a group member, etc. A malicious entity could also intercept and/or respond first before the good node responds, thus appearing to be the good node.
[0006] Commonly, P2P network attacks may attempt to disrupt or exhaust node or network resources. In PNRP, a malicious entity could also obstruct PNRP resolution by flooding the network with bad information so that other entities in the network would tend to forward requests to nonexistent nodes (which would adversely affect the convergence of searches), or to nodes controlled by the attacker. PNRP's name resolution ability could also be degraded by modifying the RESOLVE packet used to discover resources before forwarding it to a next node, or by sending an invalid RESPONSE to back to the requester that generated the RESOLVE packet. A malicious entity could also attempt to disrupt the operation of the peer-to-peer network by trying to ensure that searches will not converge by, for example, instead of forwarding the search to a node in its cache that is closer to the ID to aid in the search convergence, forwarding the search to a node that is further away from the requested ID. Alternatively, the malicious entity could simply not respond to the search request at all. The PNRP resolution could be further hampered by a malicious node sending an invalid BYE message on behalf of a valid ID. As a result, other nodes in the cloud will remove this valid ID from their cache, decreasing the number of valid nodes stored therein.
[0007] While simply validating address certificates may prevent the identity theft problem, such is ineffective against an attack that impedes PNRP resolution. An attacker can continue to generate verifiable address certificates (or have them pre-generated) and flood the corresponding IDs in the peer-to-peer cloud. If any of the nodes attempts to verify ownership of the ID, the attacker would be able to verify that it is the owner for the flooded IDs because, in fact, it is. However, if the attacker manages to generate enough IDs it can bring most of the peer-to-peer searches to one of the nodes it controls. Once a malicious node brings the search to controlled node, the attacker fairly controls and directs the operation of the network.
[0008] A malicious node may also attempt a denial of service (DoS) attack. When a P2P node changes, it may publish its new information to other network nodes. If all the nodes that learn about the new node records try to perform an ID ownership check, a storm of network activity against the advertised ID owner will occur. Exploiting this weakness, an attacker could mount an internet protocol (IP) DoS attack against a certain target by making that target very popular. For example, if a malicious entity advertises an Internet Website IP address as the updated node's ID IP, all the nodes in the peer-to-peer network that receive this advertised IP will try to connect to that IP to verify the authenticity of the record. Of course, the Website's server will not be able to verify ownership of the ID because the attacker generated this information. However, the damage has already been done. That is, the attacker convinced a good part of the peer-to-peer community to flood the IP address with validation requests and may have effectively shut it down.
[0009] Another type of DoS attack that overwhelms a node or a cloud by exhausting one or more resources occurs when a malicious node sends a large volume of invalid/valid peer address certificates (PACs) to a single node (e.g. by using FLOOD/RESOLVE/SOLICIT packets). The node that receives these PACs will consume all its CPU trying to verify all of the PACs. Similarly, by sending invalid FLOOD/RESOLVE packets, a malicious node will achieve packet multiplication within the cloud. That is, the malicious node can consume network bandwidth for a PNRP cloud using a small number of such packets because the node to which these packets are sent will respond by sending additional packets. Network bandwidth multiplication can also be achieved by a malicious node by sending bogus REQUEST messages to which good nodes will respond by FLOODing the PACs, which are of a larger size than the REQUEST.
[0010] A malicious node can also perpetrate an attack in the PNRP cloud by obstructing the initial node synch up. That is, to join the PNRP cloud a node tries to connect to one of the nodes already present in the PNRP cloud. If the node tries to connect to the malicious node, it can be completely controlled by that malicious node. Further, a malicious node can send invalid REQUEST packets when two good nodes are involved in the synchronization process. This is a type of DoS attack that will hamper the synch up. Because the invalid REQUEST packets generate FLOOD messages in response, initial node synch up may be hindered.
[0011] There exists a need in the art, therefore, for security mechanisms that will ensure the integrity of the P2P cloud by preventing or mitigating the effect of such attacks.
BRIEF SUMMARY OF THE INVENTION
[0012] The inventive concepts disclosed in this application involve a new and improved method for inhibiting a malicious node's ability to disrupt normal operation of a peer-to-peer network. Specifically, the present invention presents methods to address various types of attacks that may be launched by a malicious node, including identity theft attacks, denial of service attacks, attacks that merely attempt to hamper the address resolution in the peer-to-peer network, as well as attacks that attempt to hamper a new node's ability to join and participate in the peer-to-peer network.
[0013] The security infrastructure and methods presented allow both secure and insecure identities to be used by nodes by making them self-verifying. When necessary or opportunistic, ID ownership is validated by piggybacking the validation on existing messages or, if necessary, by sending a small inquire message. The probability of connecting initially to a malicious node is reduced by randomly selecting the connection node. Further, information from malicious nodes is identified and can be disregarded by maintaining information about prior communications requiring a future response. Denial of service attacks are inhibited by allowing the node to disregard requests when its resource utilization exceeds a predetermined limit. The ability for a malicious node to remove a valid node is reduced by requiring revocation certificates to be signed by the node to be removed.
[0014] In accordance with one embodiment of the present invention, a method of generating a self-verifiable insecure peer address certificate (PAC) that will prevent a malicious node from publishing another node's secure identification in an insecure PAC in the peer-to-peer network is presented. This method comprises the steps of generating an insecure PAC for a resource discoverable in the peer-to-peer network. The resource has a peer-to-peer identification (ID). The method further includes the step of including a uniform resource identifier (URI) in the insecure PAC from which the peer-to-peer ID is derived. Preferably, the URI is in the format “p2p://URI”. The peer-to-peer ID may also be insecure.
[0015] In a further embodiment, a method of opportunistically validating a peer address certificate at a first node in a peer-to-peer network is presented. This first node utilizes a multilevel cache for storage of peer address certificates, and the method comprises the steps of receiving a peer address certificate (PAC) purportedly from a second node and determining the PAC storage level in the multilevel cache. When the PAC is to be stored in one of two lowest cache levels, the method places the PAC in a set aside list, generates an INQUIRE message containing an ID of the PAC to be validated, and transmits the INQUIRE message to the second node. When the PAC is to be stored in an upper cache level other than one of the two lowest cache levels, the method stores the PAC in the upper cache level marked as ‘not validated’. In this case, the PAC will be validated the first time it is used. The method may also request a certificate chain for the PAC.
[0016] In a preferred embodiment, creating of the INQUIRE message comprises the step of generating a transaction ID to be included in the INQUIRE message. When an AUTHORITY message is received from the second node in response to the INQUIRE message, the PAC is removed from the set aside list and is stored in one of the two lowest cache levels. If a certificate chain was requested, the AUTHORITY message is examined to determine if the certificate chain is present and valid. If the AUTHORITY is present and valid, the PAC is stored in the one of the two lowest cache levels, and if not, it is deleted. A transaction ID may also be used in an embodiment of the invention to ensure that the AUTHORITY message is in response to a prior communication.
[0017] In a further embodiment of the present invention, a method of discovering a node in a peer-to-peer network in a manner that reduces the probability of connecting to a malicious node is presented. This method comprises the steps of broadcasting a discovery message in the peer-to-peer network without including any IDs locally registered, receiving a response from a node in the peer-to-peer network, and establishing a peering relationship with the node. In one embodiment, the step of receiving a response from a node comprises the step of receiving a response from at least two nodes in the peer-to-peer network. In this situation, the step of establishing a peering relationship with the node comprises the steps of randomly selecting one of the at least two nodes and establishing a peering relationship with the randomly selected one of the at least two nodes.
[0018] In yet a further embodiment of the present invention, a method of inhibiting a denial of service attack based on a synchronization process in a peer-to-peer network is presented. This method comprises the steps of receiving a SOLICIT message requesting cache synchronization from a first node containing a peer address certificate (PAC), examining the PAC to determine its validity, and dropping the SOLICIT packet when the step of examining the PAC determines that the PAC is not valid. Preferably, when the step of examining the PAC determines that the PAC is valid, the method further comprises the steps of generating a nonce, encrypting the nonce with a first node public key of the first node, generating an ADVERTISE message including the encrypted nonce, and sending the ADVERTISE message to the first node. When a REQUEST message is received from the first node, the method examines the REQUEST message to determine if the first node was able to decrypt the encrypted nonce, and processes the REQUEST message when the first node was able to decrypt the encrypted nonce.
[0019] Preferably, this method further comprises the steps of maintaining connection information specifically identifying the communication with the first node, examining the REQUEST message to ensure that it is specifically related to the ADVERTISE message, and rejecting the REQUEST message when it is not specifically related to the ADVERTISE message. In one embodiment, the step of maintaining connection information specifically identifying the communication with the first node comprises the steps of calculating a first bitpos as the hash of the nonce and the first node's identity, and setting a bit at the first bitpos in a bit vector. When this is done, the step of examining the REQUEST message comprises the steps of extracting the nonce and the first node's identity from the REQUEST message, calculating a second bitpos as the hash of the nonce and the first node's identity, examining the bit vector to determine if it has a bit set corresponding to the second bitpos, and indicating that the REQUEST is not specifically related to the ADVERTISE message when the step of examining the bit vector does not find a bit set corresponding to the second bitpos. Alternatively, the nonce may be used directly as the bitpos. In this case, when the REQUEST is received, the bitpos corresponding to the enclosed nonce is checked. If it is set, this is a valid REQUEST and the bitpos is cleared. Otherwise, this is an invalid REQUEST or replay attack, and the REQUEST is discarded.
[0020] In yet a further embodiment of the present invention, a method of inhibiting a denial of service attack based on a synchronization process in a peer-to-peer network comprises the steps of receiving a REQUEST message purportedly from a first node, determining if the REQUEST message is in response to prior communication with the first node, and rejecting the REQUEST message when the REQUEST message is not in response to prior communication with the first node. Preferably, the step of determining if the REQUEST message is in response to prior communication comprises the steps of extracting a nonce and an identity purportedly of the first node from the REQUEST message, calculating a bitpos as the hash of the nonce and the identity, examining a bit vector to determine if it has a bit set corresponding to the bitpos, and indicating that the REQUEST is not in response to prior communication with the first node when there is no bit set corresponding to the bitpos.
[0021] A method of inhibiting denial of service attacks based on node resource consumption in a peer-to-peer network is also presented. This method comprises the steps of receiving a message from a node in the peer-to-peer network, examining current resource utilization, and rejecting processing of the message when the current resource utilization is above a predetermined level. When a RESOLVE message is received, the step of rejecting processing of the message comprises the step of sending an AUTHORITY message to the first node. This AUTHORITY message contains an indication that the RESOLVE message will not be processed because the current resource utilization too high. When a FLOOD message is received containing a peer address certificate (PAC) and the method determines that the PAC should be stored in one of two lowest cache levels, the step of rejecting processing of the message comprises the step of placing the PAC in a set aside list for later processing. If the method determines that the PAC should be stored in a cache level higher than two lowest cache levels, the step of rejecting processing of the message comprises the step of rejecting the FLOOD message.
[0022] In another embodiment of the present invention, a method of inhibiting denial of service attacks based on node bandwidth consumption in a peer-to-peer network is presented. This method comprises the steps of receiving a request for cache synchronization from a node in the peer-to-peer network, examining a metric indicating a number of cache synchronizations performed in the past, and rejecting processing of the request for cache synchronization when the number of cache synchronizations performed in the past exceeds a predetermined maximum. In a further embodiment, the method examines the metric to determine the number of cache synchronizations performed during a predetermined preceding period of time. In this embodiment the step of rejecting processing of the request comprises the step of rejecting processing of the request for cache synchronization when the number of cache synchronizations performed in the preceding period of time exceeds a predetermined maximum.
[0023] In another embodiment of the present invention, a method of inhibiting a search based DoS attack in a peer-to-peer network comprises the steps of examining cache entries of known peer address certificates to determine appropriate nodes to which to send a resolution request, randomly selecting one of the appropriate nodes, and sending the resolution request to the randomly selected node. In one embodiment the step of randomly selecting one of the appropriate nodes comprises the step of calculating a weighted probability for each of the appropriate nodes based on the distance of the PNRP ID from the target ID. The probability of choosing a specific next hop is then determined as an inverse proportionality to the ID distance between that node and the target node.
[0024] In a further embodiment of the present invention, a method of inhibiting a search based denial of service attack in a peer-to-peer network comprises the steps of receiving a RESPONSE message, determining if the RESPONSE message is in response to a prior RESOLVE message, and rejecting the RESPONSE message when the RESPONSE message is not in response to the prior RESOLVE message. Preferably, the step of determining if the RESPONSE message is in response to a prior RESOLVE message comprises the steps of calculating a bitpos as a hash of information in the RESPONSE message, and examining a bit vector to determine if a bit corresponding to the bitpos is set therein.
[0025] In one embodiment wherein the RESPONSE message contains an address list, the method further comprises the steps of determining if the RESPONSE message has been modified in an attempt to hamper resolution, and rejecting the RESPONSE message when the RESPONSE message has been modified in an attempt to hamper resolution. Preferably the step of determining if the RESPONSE message has been modified in an attempt to hamper resolution comprises the steps of calculating a bitpos as a hash of the address list in the RESPONSE message, and examining a bit vector to determine if a bit corresponding to the bitpos is set therein.
[0026] In another embodiment of the present invention, a method of inhibiting a malicious node from removing a valid node from the peer-to-peer network comprises the steps of receiving a revocation certificate purportedly from the valid node having a peer address certificate (PAC) stored in the receiving node cache, and verifying that the revocation certificate is signed by the valid node.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] The accompanying drawings incorporated in and forming a part of the specification illustrate several aspects of the present invention, and together with the description serve to explain the principles of the invention. In the drawings:
[0028] FIG. 1 is a block diagram generally illustrating an exemplary computer system on which the present invention resides;
[0029] FIG. 2 is a simplified flow diagram illustrating security aspects of AUTHORITY packet processing in accordance with an embodiment of the present invention;
[0030] FIG. 3 is a simplified communications processing flow diagram illustrating security aspects of a synchronization phase of P2P discovery in accordance with an embodiment of the present invention;
[0031] FIG. 4 is a simplified flow diagram illustrating security aspects of RESOLVE packet processing in accordance with an embodiment of the present invention;
[0032] FIG. 5 is a simplified flow diagram illustrating security aspects of FLOOD packet processing in accordance with an embodiment of the present invention; and
[0033] FIG. 6 is a simplified flow diagram illustrating security aspects of RESPONSE packet processing in accordance with an embodiment of the present invention.
[0034] While the invention will be described in connection with certain preferred embodiments, there is no intent to limit it to those embodiments. On the contrary, the intent is to cover all alternatives, modifications and equivalents as included within the spirit and scope of the invention as defined by the appended claims.
DETAILED DESCRIPTION OF THE INVENTION
[0035] Turning to the drawings, wherein like reference numerals refer to like elements, the invention is illustrated as being implemented in a suitable computing environment. Although not required, the invention will be described in the general context of computer-executable instructions, such as program modules, being executed by a personal computer. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. Moreover, those skilled in the art will appreciate that the invention may be practiced with other computer system configurations, including hand-held devices, multi-processor systems, microprocessor based or programmable consumer electronics, network PCs, minicomputers, mainframe computers, and the like. The invention may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote memory storage devices.
[0036] FIG. 1 illustrates an example of a suitable computing system environment 100 on which the invention may be implemented. The computing system environment 100 is only one example of a suitable computing environment and is not intended to suggest any limitation as to the scope of use or functionality of the invention. Neither should the computing environment 100 be interpreted as having any dependency or requirement relating to any one or combination of components illustrated in the exemplary operating environment 100 .
[0037] The invention is operational with numerous other general purpose or special purpose computing system environments or configurations. Examples of well known computing systems, environments, and/or configurations that may be suitable for use with the invention include, but are not limited to, personal computers, server computers, hand-held or laptop devices, multiprocessor systems, microprocessor-based systems, set top boxes, programmable consumer electronics, network PCs, minicomputers, mainframe computers, distributed computing environments that include any of the above systems or devices, and the like.
[0038] The invention may be described in the general context of computer-executable instructions, such as program modules, being executed by a computer. Generally, program modules include routines, programs, objects, components, data structures, etc. that perform particular tasks or implement particular abstract data types. The invention may also be practiced in distributed computing environments where tasks are performed by remote processing devices that are linked through a communications network. In a distributed computing environment, program modules may be located in both local and remote computer storage media including memory storage devices.
[0039] With reference to FIG. 1 , an exemplary system for implementing the invention includes a general purpose computing device in the form of a computer 110 . Components of computer 110 may include, but are not limited to, a processing unit 120 , a system memory 130 , and a system bus 121 that couples various system components including the system memory to the processing unit 120 . The system bus 121 may be any of several types of bus structures including a memory bus or memory controller, a peripheral bus, and a local bus using any of a variety of bus architectures. By way of example, and not limitation, such architectures include Industry Standard Architecture (ISA) bus, Micro Channel Architecture (MCA) bus, Enhanced ISA (EISA) bus, Video Electronics Standards Associate (VESA) local bus, and Peripheral Component Interconnect (PCI) bus also known as Mezzanine bus.
[0040] Computer 110 typically includes a variety of computer readable media. Computer readable media can be any available media that can be accessed by computer 110 and includes both volatile and nonvolatile media, removable and non-removable media. By way of example, and not limitation, computer readable media may comprise computer storage media and communication media. Computer storage media includes both volatile and nonvolatile, removable and non-removable media implemented in any method or technology for storage of information such as computer readable instructions, data structures, program modules or other data. Computer storage media includes, but is not limited to, RAM, ROM, EEPROM, flash memory or other memory technology, CD-ROM, digital versatile disks (DVD) or other optical disk storage, magnetic cassettes, magnetic tape, magnetic disk storage or other magnetic storage devices, or any other medium which can be used to store the desired information and which can be accessed by computer 110 . Communication media typically embodies computer readable instructions, data structures, program modules or other data in a modulated data signal such as a carrier wave or other transport mechanism and includes any information delivery media. The term “modulated data signal” means a signal that has one or more of its characteristics set or changed in such a manner as to encode information in the signal. By way of example, and not limitation, communication media includes wired media such as a wired network or direct-wired connection, and wireless media such as acoustic, RF, infrared and other wireless media. Combinations of the any of the above should also be included within the scope of computer readable media.
[0041] The system memory 130 includes computer storage media in the form of volatile and/or nonvolatile memory such as read only memory (ROM) 131 and random access memory (RAM) 132 . A basic input/output system 133 (BIOS), containing the basic routines that help to transfer information between elements within computer 110 , such as during start-up, is typically stored in ROM 131 . RAM 132 typically contains data and/or program modules that are immediately accessible to and/or presently being operated on by processing unit 120 . By way of example, and not limitation, FIG. 1 illustrates operating system 134 , application programs 135 , other program modules 136 , and program data 137 .
[0042] The computer 110 may also include other removable/non-removable, volatile/nonvolatile computer storage media. By way of example only, FIG. 1 illustrates a hard disk drive 141 that reads from or writes to non-removable, nonvolatile magnetic media, a magnetic disk drive 151 that reads from or writes to a removable, nonvolatile magnetic disk 152 , and an optical disk drive 155 that reads from or writes to a removable, nonvolatile optical disk 156 such as a CD ROM or other optical media. Other removable/non-removable, volatile/nonvolatile computer storage media that can be used in the exemplary operating environment include, but are not limited to, magnetic tape cassettes, flash memory cards, digital versatile disks, digital video tape, solid state RAM, solid state ROM, and the like. The hard disk drive 141 is typically connected to the system bus 121 through a non-removable memory interface such as interface 140 , and magnetic disk drive 151 and optical disk drive 155 are typically connected to the system bus 121 by a removable memory interface, such as interface 150 .
[0043] The drives and their associated computer storage media discussed above and illustrated in FIG. 1 , provide storage of computer readable instructions, data structures, program modules and other data for the computer 110 . In FIG. 1 , for example, hard disk drive 141 is illustrated as storing operating system 144 , application programs 145 , other program modules 146 , and program data 147 . Note that these components can either be the same as or different from operating system 134 , application programs 135 , other program modules 136 , and program data 137 . Operating system 144 , application programs 145 , other program modules 146 , and program data 147 are given different numbers hereto illustrate that, at a minimum, they are different copies. A user may enter commands and information into the computer 110 through input devices such as a keyboard 162 and pointing device 161 , commonly referred to as a mouse, trackball or touch pad. Other input devices (not shown) may include a microphone, joystick, game pad, satellite dish, scanner, or the like. These and other input devices are often connected to the processing unit 120 through a user input interface 160 that is coupled to the system bus, but may be connected by other interface and bus structures, such as a parallel port, game port or a universal serial bus (USB). A monitor 191 or other type of display device is also connected to the system bus 121 via an interface, such as a video interface 190 . In addition to the monitor, computers may also include other peripheral output devices such as speakers 197 and printer 196 , which may be connected through a output peripheral interface 195 .
[0044] The computer 110 may operate in a networked environment using logical connections to one or more remote computers, such as a remote computer 180 . The remote computer 180 may be another personal computer, a server, a router, a network PC, a peer device or other common network node, and typically includes many or all of the elements described above relative to the personal computer 110 , although only a memory storage device 181 has been illustrated in FIG. 1 . The logical connections depicted in FIG. 1 include a local area network (LAN) 171 and a wide area network (WAN) 173 , but may also include other networks. Such networking environments are commonplace in offices, enterprise-wide computer networks, intranets and the Internet.
[0045] When used in a LAN networking environment, the personal computer 110 is connected to the LAN 171 through a network interface or adapter 170 . When used in a WAN networking environment, the computer 110 typically includes a modem 172 or other means for establishing communications over the WAN 173 , such as the Internet. The modem 172 , which may be internal or external, may be connected to the system bus 121 via the user input interface 160 , or other appropriate mechanism. In a networked environment, program modules depicted relative to the personal computer 110 , or portions thereof, may be stored in the remote memory storage device. By way of example, and not limitation, FIG. 1 illustrates remote application programs 185 as residing on memory device 181 . It will be appreciated that the network connections shown are exemplary and other means of establishing a communications link between the computers may be used.
[0046] In the description that follows, the invention will be described with reference to acts and symbolic representations of operations that are performed by one or more computer, unless indicated otherwise. As such, it will be understood that such acts and operations, which are at times referred to as being computer-executed, include the manipulation by the processing unit of the computer of electrical signals representing data in a structured form. This manipulation transforms the data or maintains it at locations in the memory system of the computer, which reconfigures or otherwise alters the operation of the computer in a manner well understood by those skilled in the art. The data structures where data is maintained are physical locations of the memory that have particular properties defined by the format of the data. However, while the invention is being described in the foregoing context, it is not meant to be limiting as those of skill in the art will appreciate that various of the acts and operation described hereinafter may also be implemented in hardware.
[0047] As introduced above, the success of a peer-to-peer (P2P) protocol depends on the protocol's ability to establish valid connections between selected entities. Because a particular user may connect to the network in various ways at various locations having different addresses, a preferred approach is to assign a unique identity to the user, and then resolve that identity to a particular address through the protocol. Such a peer-to-peer name resolution protocol (PNRP) to which the security infrastructure of the instant invention finds particular applicability is described in co-pending application Ser. No. 09/942,164, entitled Peer-To-Peer Name Resolution Protocol (PNRP) And Multilevel Cache For Use Therewith, filed on Aug. 29, 2001, the teachings and disclosure of which are hereby incorporated in their entireties by reference thereto. However, one skilled in the art will recognize from the following teachings that the security infrastructure and methods of the present invention are not limited to the particular peer-to-peer protocol of this co-pending application, but may be applied to other protocols with equal force.
[0048] As discussed in the above-incorporated co-pending application, the peer name resolution protocol (PNRP) is a peer-based name-to-address resolution protocol. Names are 256-bit numbers called PNRP IDs. Addresses consist of an IPv4 or IPv6 address, a port, and a protocol number. When a PNRP ID is resolved into an address, a peer address certificate (PAC) is returned. This certificate includes the target's PNRP ID, current IP address, public key, and many other fields. An instance of the PNRP protocol is called a node. A node may have one or more PNRP IDs registered locally. A node makes an ID-to-address mapping discoverable in PNRP via registration. Each registration includes a locally constructed peer certificate, and requires an appropriate view of the PNRP cache. Hosts which are not PNRP nodes may resolve PNRP IDs into IP addresses via a PNRP DNS gateway. A PNRP DNS gateway accepts DNS ‘A’ and ‘AAAA’ queries, performs a PNRP search for a subset of the hostname specified, and returns the results as a DNS query answer.
[0049] As indicated above, PNRP provides a peer-based mechanism associating P2P and PNRP IDs with peer address certificates (PACs). A P2P ID is a persistent 128-bit identifier. P2P IDs are created by hashing a correctly formatted P2P name. There are two types of P2P IDs, secure and insecure. A secure P2P ID is an ID with a verifiable relationship to a public key. An insecure P2P ID is any ID which is not secure. A given P2P ID may be published by many different nodes. PNRP uses a ‘service location’ suffix to ensure each published instance has a unique PNRP ID. A ‘service location’ is a 128-bit number corresponding to a unique network service endpoint. Service locations have some recognizable elements, but should be considered opaque by PNRP clients. A service location has two important properties. At any moment, only one socket in the cloud corresponds to a given service location. When two service locations are compared, the length of the common prefix for each is a reasonable measure of network proximity. Two service locations which start with the same four bits are no further apart than two which start with the same three bits.
[0050] A P2P ID is uniquely identified by its catenation with the service location. The resulting 256-bit (32 byte) identifier is called a PNRP ID. PNRP nodes register a PNRP ID by invoking PNRP services with a P2P name, authority, and several other parameters. PNRP services then creates and maintains a Peer Address Certificate (PAC) containing the submitted data. PACs include at a minimum a PNRP ID, certificate validity interval, service and PNRP address, public key, and a cryptographic signature generated over select PAC contents.
[0051] Creation and registration of PNRP IDs is only one part of the PNRP service. The PNRP service execution can be divided into four phases. The first is PNRP cloud discovery. During this phase a new node must find an existing node in the cloud it wishes to join. The cloud may be the global PNRP cloud, a site local (enterprise) cloud, or a link local cloud. Once found, the second phase of joining a PNRP cloud is entered. Once the new node has found an existing node, it performs a SYNCHRONIZE procedure to obtain a copy of the existing node's top cache level. A single cache level provides enough basis for a new node to start participating in the cloud. Once the SYNCHRONIZATION has been achieved, the next phase, active participation in the cloud, may be begun. After initialization has completed, the node may participate in PNRP ID registration and resolution. During this phase, the peer also performs regular cache maintenance. When the node is done, it enters the fourth phase, leaving the cloud. The node un-registers any locally registered PNRP IDs, then terminates.
[0052] The PNRP protocol consists of nine different types of packets, some of which have been introduced above. It should be noted, however, that in this application the names of the packets are used merely to facilitate an understanding of their functionality, and should not be taken as limiting the form or format of the packet or message itself. The RESOLVE packet requests resolution of a target PNRP ID into a PAC. A RESPONSE packet is the result of a completed RESOLVE request. The FLOOD packet contains a PAC intended for the PNRP cache of the recipient. A SOLICIT packet is used to ask a PNRP node to ADVERTISE its top level cache. The requested ADVERTISE packet contains a list of PNRP IDs for PACs in a node's top level cache. A REQUEST packet is used to ask a node to flood a subset of ADVERTISE'd PACs. An INQUIRE packet is used to insecurely ask a node whether a specific PNRP ID is registered at that node. To confirm local registration of a PNRP ID, an AUTHORITY packet is used. This packet optionally provides a certification chain to help validate the PAC for that ID. An ACK packet acknowledges receipt and/or successful processing of certain messages. Finally, the REPAIR packet is used to try to merge clouds that may be split.
[0053] Once a node is fully initialized, it may participate in the PNRP cloud by performing five types of activities. First, a node may register and un-register PNRP IDs. When a PNRP ID is registered, the PNRP service creates a peer address certificate (PAC) associating the PNRP ID, service address port and protocol, PNRP address port and protocol, and a public key. This PAC is entered into the local cache, and a RESOLVE is initiated using the new PAC as the source, and [PNRP ID+1] as the target. This RESOLVE is processed by a number of nodes with PNRP IDs very similar to the registered ID. Each recipient of the RESOLVE adds the new node's PAC to their cache, thereby advertising the new PNRP ID in the cloud. When a PNRP ID is un-registered, an updated PAC is created with a ‘revoke’ flag set. The updated PAC is flooded to all entries in the lowest level of the local cache. Each recipient of the FLOOD checks its cache for an older version of the PAC. If one is found, the recipient removes the PAC from its cache. If the PAC is removed from the lowest cache level, the recipient in turn FLOODs the revocation to the PNRP nodes represented by all other PACs in its lowest cache level.
[0054] The PNRP node may also participate in PNRP ID resolution. As discussed in the above incorporated application, PNRP IDs are resolved into PACs by routing RESOLVE messages successively closer to the target PNRP ID. When a node receives a RESOLVE, it may reject the RESOLVE back to the previous hop, respond to the previous hop with a RESPONSE, or forward the RESOLVE to a node whose PNRP ID is closer to the target ID than the node's own. The node also receives and forwards RESPONSE packets as part of resolution. The PNRP node may also initiate RESOLVEs on behalf of a local client. The PNRP service provides an API to allow asynchronous resolution requests. The local node originates RESOLVE packets, and eventually receives a corresponding RESPONSE.
[0055] The PNRP node also honors cache synchronization requests. Upon receiving a SOLICIT packet, the node responds with an ADVERTISE packet, listing the PNRP IDs in its highest cache level. The solicitor node then sends a REQUEST listing the PNRP IDs for any ADVERTISE'd PACs it wants. Each REQUESTed cache entry is then FLOODed to the REQUESTor. Finally, and as will be discussed more fully below, the PNRP also performs identity validation. Identity validation is a threat mitigation device used to validate PACs. Identity validation basically has two purposes. First, identity validation ensures that the PNRP node specified in a PAC has the PNRP ID from that PAC locally registered. Second, for secure PNRP IDs (discussed below), identity validation ensures that the PAC was signed using a key with a cryptographically provable relationship to the authority in the PNRP ID.
[0056] Having now provided a working knowledge of the PNRP system for which an embodiment of the security infrastructure of the present invention finds particular relevance, attention is now turned to the security mechanisms provided by the security infrastructure of the present invention. These mechanisms are provided by the system of the present invention to eliminate, or at a minimum mitigate, the effect of the various attacks that may be posed by a malicious node in a P2P cloud as discussed above. The PNRP protocol does not have any mechanism to prevent these attacks, nor is there a single solution to address all of these threats. The security infrastructure of the present invention, however, minimizes the disruption that may be caused by a malicious node, and may be incorporated into the PNRP protocol.
[0057] As with many successful P2P protocols, entities can be published for easy discovery. To provide security and integrity to the P2P protocol, however, each identity preferably includes an attached identity certificate. However, a robust security architecture will be able to handle both secure and insecure entities. In accordance with an embodiment of the present invention, this robustness is provided through the use of self-verifying PACs.
[0058] A secure PAC is made self-verifying by providing a mapping between the ID and a public key. This will prevent anyone from publishing a secure PAC without having the private key to sign that PAC, and thus will prevent a large number of identity theft attacks. The keeper of the ID private key uses the certificate to attach additional information to the ID, such as the IP address, friendly name, etc. Preferably, each node generates its own pair of private-public keys, although such may be provided by a trusted supplier. The public key is then included as part of the node identifier. Only the node that created the pair of keys has the private key with which it can prove that it is the creator of the node identity. In this way, identity theft may be discovered, and is, therefore, deterred.
[0059] A generic format for such certificates may be represented as [Version, ID, <ID Related Info>, Validity, Algorithms, P.sub.Issuer]K.sub.Issuer. Indeed, P2P name/URL is part of the basic certificate format, regardless of whether it is a secure or insecure ID. As used in this certificate representation, Version is the certificate version, ID is the identifier to be published, <ID Related Info> represents information to be associated with the ID, Validity represents the period of validity expressed in a pair of From-To dates expressed as Universal Date Time (aka GMT), Algorithms refers to the algorithms used for generating the key pairs, and for signing, and P.sub.Issuer is the public key of the certificate issuer. If the certificate issuer is the same as the ID owner then this is P.sub.ID the public key of the ID owner. The term K.sub.Issuer is the private key corresponding to P.sub.Issuer. If the certificate issuer is the ID owner then this is K.sub.ID, the private key of the ID owner.
[0060] In a preferred embodiment, the <ID related info> comprises the address tuple where this ID can be found, and the address tuple for the PNRP service of the issuer. In this embodiment, the address certificate becomes [Version, ID, <Address>.sub.ID, <Address>.sub.PNRP, Validity, Revoke Flag, Algorithms, P.sub.Issuer]K.sub.Issuer. In this expanded representation, the ID is the identifier to be published, which can be a Group ID or Peer ID. The <Address> is the tuple of IPv6 address, port, and protocol. <Address>.sub.ID is the address tuple to be associated with the ID. <Address>.sub.PNRP is the address tuple of the PNRP service (or other P2P service) on the issuer machine. This is preferably the address of the PNRP address of the issuer and will be used by the other PNRP nodes to verify the validity of the certificate. Validity is the period of validity expressed in a pair of From-To dates. The Revoke Flag, when set, marks a revocation certificate. The P.sub.Issuer is the public key of the certificate issuer, and the K.sub.Issuer is the private key corresponding to P.sub.Issuer. If the certificate issuer is the ID owner then this is K.sub.ID, the private key of the ID.
[0061] In a preferred embodiment of the present invention, the following conditions have to be met for a certificate to be valid. The certificate signature must valid, and the certificate cannot be expired. That is, the current date expressed as UDT must be in the range specified by the Validity field. The hash of the public key must also match the ID. If the Issuer is the same as the ID owner then the hashing of the issuer's public key into the ID has to verify. If the P.sub.Issuer is different from P.sub.ID then there must be a chain of certificates leading to a certificate signed with K.sub.ID. Such a chain verifies the relationship between the issuer and the ID owner. Additionally, in the case when a certification revocation list (CRL) is published for that class of IDs and the CRL is accessible, then the authenticator can verify that none of the certificates in the chain appear in the CRL.
[0062] The security infrastructure of the present invention also handles insecure PACs. In accordance with the present invention, an insecure PAC is made self-verifying by including the uniform resource identifier (URI) from which the ID is derived. Indeed, both secure and insecure IDs include the URI in the PAC. The URI is of the format “p2p://URI”. This will prevent a malicious node from publishing another node's secure ID in an insecure PAC.
[0063] The security infrastructure of the present invention also allows for the use of insecure IDs. The problem with insecure IDs is that they are very easy to forge: a malicious node can publish an insecure ID of any other node. Insecure IDs also open security holes wherein it becomes possible to make discovery of a good node difficult. However, by including a URI in accordance with the present invention, the insecure IDs cannot affect the secure IDs in any way. Further, the infrastructure of the present invention requires that the PACs containing insecure IDs be in the same format as secure PACs, i.e. they contain public key and private keys. By enforcing the same structure on both insecure PACs and secure PACs, the bar for generating PACs is not lowered. Further, by including a URI in the PAC it is not computationally feasible to generate a URI that maps to a specific secure ID.
[0064] One issue that arises is the timing of PAC verification, recognizing a trade off between increased P2P cloud security and increased overhead. The PAC contained in the various packets discussed above has to be verified at some point, however. This PAC verification includes checking the ID signature validity and checking if the ID corresponds to the public key for secure IDs. To balance the overhead versus security issues, one embodiment of the present invention verifies the PACs before any processing of that packet is done. This ensures that invalid data is never processed. However, recognizing that PAC verification may slow down the packet processing, which might not be suitable for certain classes of packets (e.g. RESOLVE packets), an alternate embodiment of the present invention does not verify the PAC in these packets.
[0065] In addition to PAC verification, the security infrastructure of the present invention also performs an ID ownership check to validate the PAC. As discussed above, identity theft can be discovered by simple validation of the address certificate before using that address in PNRP or other P2P protocols. This validation may entail simply verifying that the ID is the hash of the public key included in the certificate. The ownership validation may also entail the issuance of an INQUIRE packet to the address in that PAC. The INQUIRE packet will contain the ID to be verified, and a transaction ID. If the ID is present at that address, the node should acknowledge that INQUIRE. If the ID is not present at that address, the node should not acknowledge that INQUIRE. If the certificate chain is required to verify the identity, the node returns the complete certificate chain. While signature and ID->URL validation is still complex and a significant use of resources, as is validating the chain of trust in a supplied cert chain, the system of the present invention avoids any sort of challenge/response protocol, which would add an additional level of complexity to PAC validation. Further, the inclusion of the transaction ID prevents the malicious node from pre-generating the response to the INQUIREs. Additionally, this mechanism dispenses with the requirement that the PAC carry the complete certificate chain.
[0066] The ID ownership check is also facilitated in the system of the present invention by modifying the standard RESOLVE packet so that it can also perform the ID ownership check. This modified RESOLVE packet contains the ID of the address to which the RESOLVE is being forwarded. If the ID is at that address, it will send an ACK, otherwise it will send a NACK. If the ID does not process the RESOLVE or if a NACK is received, the ID is removed from the cache. In this way a PAC is validated without resorting to any sort of challenge/response protocol and without sending any special INQUIRE packet by, in essence, piggybacking an INQUIRE message with the RESOLVE. This piggybacking process will be discussed again below with respect to FIG. 2 . This procedure makes it easy to flush out invalid or stale PACs.
[0067] This identity validation check happens at two different times. The first is when a node adds a PAC to one of its lowest two cache levels. PAC validity in the lowest two cache levels is critical to PNRP's ability to resolve PNRP IDs. Performing identity validation before adding a PAC to either of these two levels mitigates several attacks. ID ownership is not performed if the PAC is added to any higher level cache because of the turnover in these higher levels. It has been determined that nearly 85% of all PAC entries in the higher levels of cache are replaced or expire before they are ever used. As such, the probability of seeing any effect from having an invalid PAC in these higher levels is low enough not to justify performing the ID validation when they are entered.
[0068] When it is determined that an entry would belong in one of the two lowest cache levels, the PAC is placed in a set aside list until its identity can be validated. This first type of identity validation uses the INQUIRE message. Such an identity validation confirms a PAC is still valid (registered) at its originating node, and requests information to help validate authority of the originating node to publish that PAC. One flag in the INQUIRE message is defined for the ‘flags’ field, i.e. RF_SEND_CHAIN, that requests the receiver to send a certificate chain (if any exists) in an AUTHORITY response. If the receiver of the INQUIRE does not have authority to publish the PAC or if the PAC is no longer locally registered, the receiver simply drops the INQUIRE message. Since the local node does not receive a proper response via an AUTHROITY message, the bad PAC will never be entered into its cache, and therefore can have no malicious effect on its operation in the P2P cloud.
[0069] If the receiver of the INQUIRE does have the authority to issue the PAC and if it is still locally registered, that node will respond 200 to the INQUIRE message with an AUTHORITY message as illustrated in FIG. 2 . While not illustrated in FIG. 2 , the receiving node in an embodiment of the present invention checks to see if the AUTHORITY message says that the ID is still registered at the node which sent the AUTHORITY. Once the local node determines 202 that this AUTHORITY message is in response to the INQUIRE message, it removes the PAC from the set aside list 204 . If the certificate chain was requested 206 , the AUTHORITY message is checked to see if the certificate chain is present and valid 208 . If the certificate chain is present and valid, then the PAC is added to the cache and marked as valid 210 . Otherwise, the PAC is deleted 212 . If the certificate chain was not requested 206 , then the PAC is simply added to the cache and marked as valid 210 .
[0070] As may now be apparent, this AUTHORITY message is used to confirm or deny that a PNRP ID is still registered at the local node, and optionally provides a certificate chain to allow the AUTHORITY recipient to validate the node's right to publish the PAC corresponding to the target ID. In addition to the INQUIRE message, the AUTHORITY message may be a proper response to a RESOLVE message as will be discussed below. The AUTHORITY message includes various flags that may be set by the receiving node to indicate a negative response. One such flag is the AF_REJECT_TOO_BUSY flag, which is only valid in response to a RESOLVE. This flag indicates that the host is too busy to accept a RESOLVE, and tells the sender that it should forward the RESOLVE elsewhere for processing. While not aiding in the identity validation, it is another security mechanism of the present invention to prevent a DoS attack as will be discussed more fully below. The flag AF_INVALID_SOURCE, which is only valid in response to a RESOLVE, indicates that the Source PAC in the RESOLVE is invalid. The AF_INVALID_BEST_MATCH flag, which is also only valid in response to a RESOLVE, indicates that the ‘best match’ PAC in the RESOLVE is invalid. The AF_UNKNOWN_ID flag indicates that the specified ‘validate’ PNRP ID is not registered at this host. Other flags in the AUTHORITY message indicate to the receiving node that requested information is included. The AF_CERT_CHAIN flag indicates that a certificate chain is included that will enable validation of the relationship between the ‘validate’ PNRP ID and the public key used to sign the PAC. The AUTHORITY message is only sent as an acknowledgement/response to either the INQUIRE or RESOLVE messages. If an AUTHORITY is ever received out of this context, it is discarded.
[0071] The second time that identity validation is performed is opportunistically during the RESOLVE process. As discussed, PNRP caches have a high rate of turnover. Consequently, most cache entries are overwritten in the cache before they are ever used. Therefore, the security infrastructure of the present invention does not validate these PACs until and unless they are actually used. When a PAC is used to route a RESOLVE path, the system of the present invention piggybacks identity validation on top of the RESOLVE packet as introduced above. The RESOLVE contains a ‘next hop’ ID which is treated the same as the target ID in an INQUIRE packet. This RESOLVE is then acknowledged with an AUTHORITY packet, the same as is expected for an INQUIRE discussed above. If an opportunistic identity validation fails, the receiver of the RESOLVE is not who the sender believes they are. Consequently, the RESOLVE is routed elsewhere and the invalid PAC is removed from the cache.
[0072] This process is also illustrated in FIG. 2 . When a PNRP node P receives an AUTHORITY packet 200 with the header Message Type field set to RESOLVE 202 , the receiving node examines the AUTHORITY flags to determine if this AUTHORITY flag is negative 214 , as discussed above. If any of the negative response flags are set in the AUTHORITY message, the PAC is deleted 216 from the cache and the RESOLVE is routed elsewhere. The address to which the RESOLVE was sent is appended to the RESOLVE path and marked REJECTED. The RESOLVE is then forwarded to a new destination. If the AUTHORITY is not negative and if the certificate chain was requested 218 , the AUTHORITY message flag AF_CERT_CHAIN is checked to see if the certificate chain is present. If it is present the receiving node should perform a chain validation operation on the cached PAC for the PNRP ID specified in validate. The chain should be checked to ensure all certificates in it are valid, and the relationship between the root and leaf of the chain is valid. The hash of the public key for the chain root should, at a minimum, be compared to the authority in the PACs P2P name to ensure they match. The public key for the chain leaf should be compared against the key used to sign the PAC to ensure they match. If any of these checks fail or if the certificate chain is not present when requested 220 , the PAC should be removed from the cache 222 and the RESOLVE reprocessed. If the requested certificate chain is included and is validated 220 , the PAC corresponding to the validate PNRP ID should be marked as fully validated 224 . If desired, the PNRP ID, PNRP service address, and validation times may be retained from the PAC and the PAC itself deleted from the cache to save memory.
[0073] As an example of this identity validation, assume that ‘P’ is a node requesting an identity validation for PNRP ID ‘T’. ‘N’ is the node receiving the identity validation request. This could happen as a result of P receiving either an INQUIRE packet with target ID=T, or a RESOLVE packet with next hop=T. N checks its list of PNRP IDs registered locally. If T is not in that list, then the received packet type is checked. If it was an INQUIRE, N silently drops the INQUIRE request. After normal retransmission attempts expire, P will discard the PAC as invalid and processing is done. If it was a RESOLVE, N responds with an AUTHORITY packet indicating ID T is not locally registered. P then sends the RESOLVE elsewhere. If T is in the list of PNRP IDs at N, N constructs an AUTHORITY packet and sets the target ID to T. If T is an insecure ID, then N sends the AUTHORITY packet to P. If T is a secure ID, and the authority for the secure ID is the key used to sign the PAC, then N sends the AUTHORITY packet to P. If neither of these are true and if the RF_SEND_CHAIN flag is set, then N retrieves the certificate chain relating the key used to sign the PAC to the authority for PNRP ID T. The certificate chain is inserted into the AUTHORITY packet, and then N sends the AUTHORITY packet to P. At this point, if T is an insecure ID processing is completed. Otherwise, P validates the relationship between the PAC signing key and the authority used to generate the PNRP ID T. If the validation fails, the PAC is discarded. If validation fails and the initiating message was a RESOLVE, P forwards the RESOLVE elsewhere.
[0074] As may now be apparent from these two times that identity ownership verification is performed, through either the INQUIRE or the modified RESOLVE packet, an invalid PAC cannot be populated throughout the P2P cloud using a FLOOD, and searches will not be forwarded to non-existent or invalid IDs. The PAC validation is necessary for FLOOD because, if the FLOOD packet is allowed to propagate in the network without any validation, then a DoS attack may result. Through these mechanisms, a popular node will not be flooded with ID ownership check because its ID will belong to only a very few nodes' lowest two cache levels.
[0075] As described more fully in the above referenced co-pending application, a PNRP node N learns about a new ID in one of four ways. It may learn of a new ID through the initial flooding of a neighbor's cache. Specifically, when a P2P node comes up it contacts another node member of the P2P cloud and initiates a cache synchronization sequence. It may also learn of a new ID as a result of a neighbor flooding a new record of its lowest cache. For example, assume that node N appears as an entry in the lowest level cache of node M. When M learns about a new ID, if the ID fits in its lowest level cache, it will flood it to the other entries in that cache level, respectively to N. A node may also learn of a new ID as a result of a search request. The originator of a search request inserts its address certificate in the request, and the PAC for the ‘best match’ to the search request so far also inserts its PAC into the request. In this way, all of the nodes along the search request path will update their cache with the search originator's address, and the best match's address. Similarly, a node may learn of a new ID as a result of a search response. The result of a search request travels a subset of the request path in reverse order. The nodes along this path update their cache with the search result.
[0076] According to PNRP, when the node first comes up it discovers a neighbor. As discussed above, however, if the node that is first discovered is a malicious node, the new node can be controlled by the malicious node. To prevent or minimize the possibility of such occurrence, the security infrastructure of the present invention provides two mechanisms to ensure secure node boot up. The first is randomized discovery. When a node tries to discover another node that will allow it to join the PNRP cloud, the last choice for discovery is using multicast/broadcast because it is the most insecure discovery method of PNRP. Due to the nature of discovery it is very difficult to distinguish between a good and bad node. Therefore, when this multicast/broadcast method is required, the security infrastructure of the present invention causes the node to randomly select one of the nodes who responded to the broadcast discovery message (MARCOPOLO or an existing multicast discovery protocol e.g., SSDP). By selecting a random node, the system of the present invention minimizes the probability of selecting a malicious node. The system of the present invention also performs this discovery without using any of its IDs. By not using IDs during discovery, the system of the present invention prevents the malicious node from targeting a specific ID.
[0077] A second secure node boot up mechanism is provided by a modified sync phase during which the node will maintain a bit vector. This modified synch phase mechanism may best be understood through an example illustrated in the simplified flow diagram of FIG. 3 . Assume that Alice 226 sends a SOLICIT 228 to Bob 230 with her PAC in it. If Alice's PAC is not valid 232 , Bob 230 simply drops the SOLICIT 234 . If the PAC is valid, Bob 230 will then maintain a bit vector for storing the state of this connection. When this SOLICIT is received, Bob 230 generates 236 a nonce and hashes it with Alice's PNRP ID. The resulting number will be used as an index in this bit vector that Bob will set. Bob 230 then responds 238 to Alice 226 with an ADVERTISE message. This ADVERTISE will contain Bob's PAC and a nonce encrypted with Alice's public key, apart from other information, and will be signed by Bob 230 . When Alice 226 receives this ADVERTISE, she verifies 240 the signature and Bob's PAC. If it cannot be verified, it is dropped 241 . If it can be verified, Alice 226 then decrypts 242 the nonce. Alice 226 will then generate 244 a REQUEST that will contain this nonce and Alice's PNRP ID. Bob 230 will process 246 this REQUEST by hashing Alice's PNRP ID with the nonce sent in the REQUEST packet. If 248 the bit is set in the bit vector having the hashed results as an index, then Bob will clear the bits and start processing the REQUEST 250 . Otherwise, Bob will ignore the REQUEST 252 as it may be a replay attack.
[0078] This makes the node boot up a secure process because the sequence cannot be replayed. It requires minimal overhead in terms of resources consumed, including CPU, network ports, and network traffic. No timers are required to be maintained for the state information, and only the ID that initiated the sync up will be sent data. Indeed, this modified sync phase is asynchronous, which allows a node to process multiple SOLICITs simultaneously.
[0079] Many of the threats discussed above can be minimized by controlling the rate at which the packets are processed, i.e. limiting node resource consumption. The idea behind this is that a node should not consume 100% of its CPU trying to process the PNRP packets. Therefore, in accordance with an embodiment of the present invention a node may reject processing of certain messages when it senses that such processing will hinder its ability to function effectively.
[0080] One such message that the node may decide not to process is the RESOLVE message received from another node. This process is illustrated in simplified form in FIG. 4 . Once a RESOLVE message is received 254 , the node will check 256 to see if it is currently operating at a CPU capacity greater than a predetermined limit. If its CPU is too busy to process the RESOLVE message, it will send 258 an AUTHORITY message with the AF_REJECT_TOO_BUSY flag set indicating its failure to process the request because it is too busy. If the CPU is not too busy 256 , the node will determine 260 if all of the PACs in the RESOLVE message are valid, and will reject 262 the message if any are found to be invalid. If all of the PACs are valid 260 , the node will process 264 the RESOLVE.
[0081] If the node can respond 266 to the RESOLVE, the node will 268 convert the RESOLVE into a RESPONSE and send it to the node from which it received the RESOLVE. If, however, the target ID is not locally registered, the node will 270 calculate the bitpos as the hash of the fields in the RESOLVE and will set the corresponding bitpos in the bit vector. As discussed briefly above, this bit vector is used as a security mechanism to prevent the processing of erroneous reply messages when the node has not sent out any messages to which a reply is expected. The node finds the next hop to which to forward the RESOLVE, with the appropriate modifications to evidence its processing of the message. If 272 the node to which the RESOLVE is to be forwarded has already been verified, the node simply forwards 276 the RESOLVE to that next hop. If 272 this selected next hop has not yet been verified, the node piggybacks 274 an ID ownership request on the RESOLVE and forwards 276 it to that node. In response to the piggybacked ID ownership request, the node will expect to receive an AUTHORITY message as discussed above, the process for which is illustrated in FIG. 2 . As illustrated in FIG. 2 , if a validating AUTHORITY is not received at step 214 , the PAC of the node to which the RESOLVE was forwarded is deleted 216 from the cache and the RESOLVE is reprocessed from step 254 of FIG. 4 .
[0082] Another message that the node may decide not to process because its CPU is too busy is the FLOOD message. In this process, illustrated in simplified form in FIG. 5 , if 278 the new information present in the FLOOD goes to either of the lowest two cache levels, the PAC is checked to determine if it is valid 280 . If the PAC is not valid, the FLOOD is rejected 284 . However, if the PAC is valid 280 , it is put into a set-aside list 282 . The entries in the set-aside list are taken at random intervals and are processed when the CPU is not too busy. Since these entries are going to be entered in the lowest two levels of cache, both the ID verification and the ownership validation are performed as discussed above. If 278 the new information present in the FLOOD goes to the higher cache levels and the CPU is too busy to process them 286 , then they are discarded 288 . If the node has available CPU processing capacity 286 , the PAC is checked to determine if it is valid 290 . If it is, then the PAC is added to the cache 292 , otherwise the FLOOD is rejected 294 .
[0083] Node boot up (SYNCHRONIZE) is another process that consumes considerable resources at a node, including not only CPU processing capacity but also network bandwidth. However, the synchronization process is required to allow a new node to fully participate in the P2P cloud. As such, the node will respond to the request from another node for the boot up if it has enough available resources at the given time. That is, as with the two messages just discussed, the node may refuse to participate in the boot up if its CPU utilization is too high. However, since this process consumes so much capacity, a malicious node can still exploit this by launching a large number of such sequences. As such, an embodiment of the security infrastructure of the present invention limits the number of node synchronizations that may be performed by a given node to prevent this attack. This limitation may additionally be time limited so that a malicious node cannot disable a node from ever performing such a synchronization again in the future.
[0084] Also discussed above were many search based attacks that could be launched or caused by a malicious node. To eliminate or minimize the effect of such search based attacks, the system of the present invention provides two mechanisms. The first is randomization. That is, when a node is searching for an appropriate next hop to which to forward a search request (RESOLVE), it identifies a number of possible candidate nodes and then randomly selects one ID out of these candidate IDs to which to forward the RESOLVE. In one embodiment, three candidate nodes are identified for the random selection. The IDs may be selected based on a weighted probability as an alternative to total randomization. One such method of calculating a weighted probability that the ID belongs to a non-malicious node is based on the distance of the PNRP ID from the target ID. The probability is then determined as an inverse proportionality to the ID distance between that node and the target node. In any event, this randomization will decrease the probability of sending the RESOLVE request to a malicious node.
[0085] The second security mechanism that is effective against search based attacks utilizes the bit vector discussed above to maintain state information. That is, a node maintains information identifying all of the RESOLVE messages that it has processed for which a response has not yet been received. The fields that are used to maintain the state information are the target ID and the address list in the RESOLVE packet. This second field is used to ensure that the address list has not been modified by a malicious node in an attempt to disrupt the search. As discussed above with the other instances of bit vector use, the node generates a hash of these fields from the RESOLVE and sets the corresponding bitpos in the bit vector to maintain a history of the processing of that RESOLVE.
[0086] As illustrated in the simplified flow diagram of FIG. 6 , when a RESPONSE message is received 296 from another node, the fields in this RESPONSE message are hashed 298 to calculate the bitpos. The node then checks 300 the bit vector to see if the bitpos is set. If the bit is not set, meaning that this RESPONSE is not related to an earlier processed RESOLVE, then the packet is discarded 302 . If the bitpos is set, meaning that this RESPONSE is related to an earlier processed RESOLVE, the bitpos is reset 304 . By resetting the bitpos, the node will ignore further identical RESPONSE messages that may be sent as part of a playback attack from a malicious node. The node then checks to make sure that all of the PACs in the RESPONSE message are valid 306 before processing the RESPONSE and forwarding it to the next hop. If any of the PACs are invalid 306 , then the node will reject 310 the packet.
[0087] The RESOLVE process mentions converting a RESOLVE request into a RESPONSE. This RESPONSE handling just discussed involves ensuring the RESPONSE corresponds to a recently received RESOLVE, and forwarding the RESPONSE on to the next hop specified. As an example, assume that node P receives a RESPONSE packet S containing a target PNRP ID, a BestMatch PAC, and a path listing the address of all nodes which processed the original RESOLVE before this node, ending with this node's own PNRP address. Node P acknowledges receipt of the RESPONSE with an ACK. Node P checks the RESPONSE path for its own address. Its address must be the last entry in the address list for this packet to be valid. Node P also checks its received bit vector to ensure that the RESPONSE matches a recently seen RESOLVE. If the RESPONSE does not match a field in the received bit vector, or if P's address is not the last address in the path list, the RESPONSE is silently dropped, and processing stops. P validates the BestMatch PAC and adds it to its local cache. If the BestMatch is invalid, the RESPONSE is silently dropped, and processing stops. P removes its address from the end of the RESPONSE path. It continues removing entries from the end of the RESPONSE path until the endmost entry has a flag set indicating a node that ACCEPTED the corresponding RESOLVE request. If the path is now empty, the corresponding RESOLVE originated locally. PNRP does an identity validation check on the BestMatch. If the identity validation check succeeds, the BestMatch is passed up to the request manager, else a failure indication is passed up. If the path is empty, processing is complete. If the path is not empty, the node forwards the RESPONSE packet to the endmost entry in the path list.
[0088] A need for a PNRP address certificate revocation exists whenever the published address certificate becomes invalid prior to the certificate expiration date (Validity/To field). Examples of such events are when a node is gracefully disconnecting from the P2P network, or when a node is leaving a group, etc. The revocation mechanism of the present invention utilizes the publishing of a revocation certificate. A revocation certificate has the Revoke Flag set, and the From date of the Validity field set to the current time (or the time at which the certificate is to become revoked) and the To field set to the same value as the previously advertised certificates. All the certificates for which all the following conditions are met are considered to be revoked: the certificate is signed by the same issuer; the ID matches the ID in the revocation certificate; the Address fields match the ones in the revocation certificate; the To date of the Validation field is the same as the To date of the Validation filed in the revocation certificate; and the From date of the Validation field precedes the From date of the Validation filed in the revocation certificate. Since the revocation certificate is signed, it ensures that a malicious node cannot disconnect anyone from the cloud.
[0089] The foregoing description of various embodiments of the invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Numerous modifications or variations are possible in light of the above teachings. The embodiments discussed were chosen and described to provide the best illustration of the principles of the invention and its practical application to thereby enable one of ordinary skill in the art to utilize the invention in various embodiments and with various modifications as are suited to the particular use contemplated. All such modifications and variations are within the scope of the invention as determined by the appended claims when interpreted in accordance with the breadth to which they are fairly, legally, and equitably entitled.
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A security infrastructure and methods are presented that inhibit the ability of a malicious node from disrupting the normal operations of a peer-to-peer network. The methods of the invention allow both secure and insecure identities to be used by nodes by making them self-verifying. When necessary or opportunistic, ID ownership is validated by piggybacking the validation on existing messages. The probability of connecting initially to a malicious node is reduced by randomly selecting to which node to connect. Further, information from malicious nodes is identified and can be disregarded by maintaining information about prior communications that will require a future response. Denial of service attacks are inhibited by allowing the node to disregard requests when its resource utilization exceeds a predetermined limit. The ability for a malicious node to remove a valid node is reduced by requiring that revocation certificates be signed by the node to be removed.
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This invention relates to a method and apparatus for monitoring pressure and, more particularly, to applications of pressure monitoring in hydrocarbon wells.
BACKGROUND OF THE INVENTION
The equipment used in drilling, completion and working over of hydrocarbon wells in the past has almost entirely been a matter of brute force rather than finesse. Drilling rigs in particular and workover rigs to a lesser extent are characterized by massive machinery, high horsepower pumps and a brute force approach to problems. In contrast, coiled or spooled tubing units are much more finesse oriented because the pipe that comprises the work string is much smaller, much thinner and much less capable of accommodating large forces. At one time, coiled tubing units were widely known as an invitation to a fishing job because there were so many mechanical failures of the work string or the loss of bottom hole components in wells.
It is a tribute to the manufacturers of coiled tubing and coiled tubing equipment and a tribute to operators of coiled tubing equipment that the reliability of coiled tubing operations has increased dramatically over the years. In addition, the relative attractiveness of coiled tubing operations as compared to conventional workover rig operations has improved substantially to the extent that coiled tubing units have taken considerable market share from workover rigs in the completion and reworking of hydrocarbon wells.
So called pressure snubbers are known in the art and are used between a fluctuating pressure source and a gauge to protect the gauge from pressure spikes and to damp pressure fluctuations. These devices comprise a fitting having a porous metal insert or a single perforation. A gauge or pressure sensor is threaded into the fitting.
Relevant to this invention are the disclosures in U.S. Pat. Nos. 3,749,185; 4,297,880; 6,109,367 and 6,421,298.
SUMMARY OF THE INVENTION
In one aspect of this invention, a pressure source such as a pump provides an output pressure that fluctuates widely and rapidly. In order to provide pressure sensings that are meaningful, a pressure measuring conduit connects to the pressure source and includes a damper, leaving the main flow line of the pressure source undamped. The damper reduces the fluctuations of the output pressure to less than 1% of the average outlet pressure and preferably much less. The damped pressure is sensed by a conventional sensor and displayed on a screen in real time so the user can make decisions based on the damped pressure sensings. The values are preferably displayed as time versus damped pressure so the trends may be readily seen and action taken in response to the trends seen. This is particularly important when actions occur in response to pressure differentials that are smaller than or masked by the pressure fluctuations. This situation may occur in many environments, such as in the use of downhole tools in hydrocarbon wells which are powered or manipulated by hydraulic pressure supplied from the surface. Many other applications will become apparent to those skilled in the art.
In another aspect of this invention, a particularly effective and inexpensive damper is described, comprising a pair of needle valves in series. It is not clear exactly why a pair of needle valves are so effective in damping pressure fluctuations. Although not wishing to be bound by any theory of operation, a theory will be advanced hereinafter. Because the needle valves are adjustable, the size and shape of openings are adjustable. It is clear that opening the needle valves completely reduces their damping effectiveness.
In another aspect of this invention, operation of a downhole motor is monitored and decisions made in response to a pressure differential between the pump pressure supplied at a time when the motor is idling and when the motor is under load. In a typical situation, the motor is equipped with a bit or mill for drilling. When the motor is approaching a stall, or being significantly overloaded, this pressure differential increases in a manner that is recognizable. Stalling a turbine type liquid driven motor is never desirable for a variety of reasons, including wear on resilient parts on the inside of the motor or, as described more fully below, the fatigue on a coiled tubing work string.
It is an object of this invention to provide an improved method and apparatus for monitoring pressure.
Another object of this invention is to provide a method and apparatus for sensing pressure of a source which fluctuates widely and rapidly.
A further object of this invention is to provide applications for pressure monitoring techniques that involve operating downhole tools and equipment in hydrocarbon wells.
These and other objects of this invention will become more fully apparent as this description proceeds, reference being made to the accompanying drawings and appended claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a simplified prior art chart of time versus pressure showing the fluctuation of conventional high pressure multiplex pumps;
FIG. 2 is a schematic view of the pressure monitoring system of this invention;
FIG. 3 is an exploded view of the pressure damper and pressure sensor;
FIG. 4 is a schematic view relating to a theory of operation of the pressure damper; and
FIGS. 5 and 6 are pictorial views of a display of this invention.
FIGS. 5 and 6 are pictorial views of a display of this invention; and
FIG. 7 is a graph illustrating the effectiveness of this invention.
DETAILED DESCRIPTION
The discharge pressure of high pressure multiplex pumps used to power or manipulate downhole tools in hydrocarbon wells fluctuates so widely and so rapidly that pertinent pressure changes are often masked by, or are smaller than, the fluctuations. This is illustrated in FIG. 1 which is a graph of time versus pressure taken downstream of a conventional pressure snubber that is supposed to damp pressure fluctuations. Every pump acts slightly differently and the fluctuations vary with the operating speed of the pump and other factors. Basically, however, every time the discharge valve of a high pressure multiplex pump opens, a surge of high pressure liquid leaves the pump producing an upward pressure spike. Because most liquids range from mainly incompressible to slightly incompressible, the pressure surges dissipate as the liquid moves down the flow line into which it is discharged. This causes a reduction in pressure at the pump outlet until the next discharge valve opens.
This invention was developed, and will be described, in conjunction with the operation of so called mud motors, i.e. downhole motors operated by high pressure liquids, gases or mixtures pumped through a work string extending into a hydrocarbon well. These motors will be described using a liquid but it will be understood that gases or mixtures are equally useable. The term mud motor is often misleading because, except in a drilling rig, it is not mud that is pumped down the work string but a liquid, gas or mixture that is clearly not drilling mud. A better name is a hydraulic motor.
It is recognized that this invention has considerable utility in other applications, particularly the operation of other downhole tools, such as the setting of whipstocks, setting of packers, pumping wiper plugs during cementing operations, setting of liners and other situations where downhole tools are operated or manipulated by hydraulic pressure delivered from the surface. In addition, the invention is useful in other operations relating to hydrocarbon wells such as the monitoring of flow from a well which has been recently stimulated. Other applications outside the field of hydrocarbon wells will be apparent to those skilled in the art.
Hydraulic motors are widely used in drilling deviated wells, in completing hydrocarbon wells and in reworking hydrocarbon wells. Many of such motors are of a size and operated on the end of such robust work strings that they and the work strings can take considerable abuse. Hydraulic motors used on coiled or spooled tubing units are in a different category because the coiled tubing work strings are not robust and must be handled with care for a variety of reasons, one of which is to prevent failure due to fatiguing of the metal from which the tubing is made. In addition, mud motors used on coiled tubing strings are usually used inside casing and therefore are typically of smaller diameter and therefore less robust than motors used on drilling rigs.
Referring to FIGS. 2-5 , this invention is described in conjunction with a coiled tubing unit being used to drill out a bridge plug, which is a common application of this invention. A typical hydrocarbon well 10 comprises a bore hole 12 drilled into the earth to penetrate one or more hydrocarbon bearing formations 14 , 16 . A pipe string 18 is cemented in the earth by a cement annulus 20 . Perforations 22 , 24 have been created to communicate the formations 14 , 16 with the inside of the pipe string 18 . A bridge plug 26 , cement plug 28 and sand bridge 30 have been placed between the formations 14 , 16 to isolate them temporarily, as is commonly done during completion of the well 10 where the formations 14 , 16 are separately fraced.
A coiled tubing unit 32 of any suitable type is illustrated as suspending a string of coiled tubing 34 in the well providing a hydraulic motor 36 and a bit or mill 38 on the lower end for circulating out the sand bridge 30 and drilling up the cement plug 28 and the bridge plug 26 . The coiled tubing 34 is taken off a spool 40 and run over a wheel or arc support 42 and guided by an arcuate support (not shown) and forced into the well 10 by a conventional injection head 44 . A typical example of the care given to the treatment of coiled tubing 34 is that the tubing is allowed to cycle over the wheel or arc support 42 only a small number of times because experience has shown this is the location where fatiguing of the metal occurs. The number of cycles before failure is largely a function of pressure inside the coiled tubing and, for example, above 7000 psi, the number of cycles is limited by safety considerations to between ten and twenty. If a cycle limit is reached, the coiled tubing 34 is pulled from the well 10 and a quantity of tubing is cut off the lower end so the next time the tubing is run into the well, a different section of tubing is supported on the wheel 42 .
All of this activity is expensive, partly due to the pricing policy of coiled tubing unit owners justified by wear and tear on the coiled tubing 34 and partly due to the time and effort necessary to pull the tubing from the well, detach the bottom hole assembly 36 , 38 , cut the tubing, reattach the bottom hole assembly and run back into the well. In any event, it is highly desirable to minimize the number of times the coiled tubing 34 is moved over the wheel 42 .
When a motor 36 is used on the end of a coiled tubing string 34 to drill up a downhole component in a hydrocarbon well, there are many times when the coiled tubing must be pulled up and down, or cycled, over the wheel 42 . A very common occurrence is when too much weight is applied to the motor, as may occur when trying to washout the sand bridge 30 or drill the plugs 26 , 28 too rapidly. Relying on conventional pressure readings shown in FIG. 1 is useless either because pertinent pressure information is masked by the fluctuations or because the time delay of prior art equipment results in a tool operating before pressure readings are obtained. Thus, prior art operation of hydraulic motors on the end of coiled tubing is largely a matter of feel, experience and intuition, all of which are difficult and expensive to teach and learn. Much learning comes from failures but failure to pick up the coiled tubing 34 and applying too much weight stalls the motor and potentially damages or ruins it. The lesser evil, i.e. picking up too often on the coiled tubing 34 to slow down drilling, cycles the tubing over the arc support 42 too frequently and fatigues the coiled tubing which must be removed from the well, cut off and run back into the well, at great expense.
As shown in FIG. 2 , a pump 46 delivers high pressure liquid through a main flow line 48 into the coiled tubing 34 in a conventional manner. Pressure in the flow line 48 is undamped and fluctuates as shown in FIG. 1. A pressure fitting 50 on the flow line 48 connects to a damper 52 which connects to a suitable pressure sensor 54 . The function of the damper 52 is to damp the pressure fluctuations shown in FIG. 1 to an extent that pertinent pump pressure changes are not masked by the fluctuations. Because the damper 52 is not in the main flow line 48 , there is no energy loss in the damping process which is typical of situations where the entire flow stream is damped, as in the case of mud pumps on drilling rigs.
To this end, the damper 52 is of a type that damps the fluctuations so they do not exceed 1% of the average pump pressure, preferably so they do not exceed ½ of 1% of the average pump pressure and ideally so they do not exceed 0.2% of the average pump pressure. Thus, on a typical drilling job with a coiled tubing unit where pump pressure may be on the order of 10,000 psi, the fluctuations are damped to be less than 100 psi, preferably less than 50 psi and ideally less than 20 psi.
Although many designs of dampers may be effective to this extent, a preferred approach is shown in FIGS. 3 and 4 where the damper 52 comprises a pair of conventional needle valves 56 placed in series. The needle valves 56 each comprise a valve body 58 having a rotatable handle 60 for advancing a pointed valve element into and through a passage 62 . The housing 58 typically has a male end 64 at one end and female threads in the other end.
Although not being bound by any particular theory of operation, FIG. 4 illustrates what is thought to be happening. On the left or upstream end of FIG. 4 , there are large pressure waves suggesting the fluctuations shown in FIG. 1 . Between the valve bodies 58 in the flow passage or cavity between the needle valves 56 , there is a reduction in the magnitude of pressure waves because the waves have to pass through the small opening 62 of the upstream valve body 58 . Downstream of the right or downstream valve body, there are smaller pressure waves than in the cavity between the valve bodies 58 because the pressure waves have to travel through the small opening 62 in the downstream valve body 58 . In this fashion, the wildly fluctuating pump pressure of FIG. 1 is damped so substantially that no comparable fluctuations are apparent on the display screen used to show a trace of pump pressure. The effect of the second flow restriction is seen most clearly by reducing the flow passage through the upstream valve, viewing the pressure fluctuations and then reducing the flow passage through the downstream valve. When the first valve is restricted, the pressure pulses seen by the sensor 54 are smaller but still pronounced. Restricting the downstream valve reduces the pressure pulses dramatically to a range of 3-20 psi.
The pressure sensor 54 may be of any suitable type and is conveniently Model MSP-300 obtained from Measurement Specialties, Valley Forge, Pa. This particular sensor is an analog sensor which necessitates the user of an analog-to-digital converter as will be more fully apparent hereinafter.
Referring to FIG. 2 , an output 66 from the pressure sensor 54 connects to a data logger assembly 68 which is conveniently portable. The data logger assembly 68 includes an analog-to-digital converter 70 connected to a microprocessor 72 . A real time clock 74 provides another input to the microprocessor 72 so that pressure readings obtained from the sensor 54 can be matched with the time when they are taken. The microprocessor 72 may be controlled by suitable software to accept pressure data at predetermined intervals, such as one second or any other suitable interval. A memory device 76 is provided to temporarily store data. An output 78 from the microprocessor 72 operates a transmitter 80 to deliver time/pressure data to a graphical display assembly 82 . The transmitter 80 is preferably wireless using convenient technology such as a low power radio frequency approach.
The graphical display assembly 82 may be of any suitable type, such as a computer screen or a special purpose display of a size small enough to carry easily. The display assembly 82 comprises a receiver 84 receiving communication from the transmitter 80 , a microprocessor 86 , a memory device 88 , a user input 90 and a display 92 . The display 92 is typically a computer monitor or other suitable electronically manipulated screen. It will accordingly be seen that time/pressure data from the transmitter 80 passes through the receiver 84 into the microprocessor 86 and is stored in the memory device 88 . The microprocessor 86 delivers data to the display 92 at suitable intervals to construct a time/pressure trace 94 , as shown in FIG. 5 . indicative of damped pressure readings from the sensor 54 .
In coiled tubing operations of the type described, it is often desirable to know the pressure at the surface in the annulus between the coiled tubing 34 and the pipe string 18 . To this end, a pressure fitting 96 is attached to the wellhead 98 and provides a pressure sensor 100 having an output 102 connected to an analog-to-digital converter 104 in the data logger assembly 68 . Pressure in the annulus measured by the sensor 100 typically does not fluctuate significantly so no damper is necessary. The components of the assembly 68 are sufficiently capable to accommodate additional data, so the data transmitted to the graphical display device assembly 82 includes a stream of time/pressure information indicating pressure in the annulus. This data is stored in the memory device 88 and shown on the display 9 , 2 as a second trace 101 , as shown in FIG. 5 .
The absolute value of the pressure in the annulus normally depends on the size of the choke (not shown) used to control flow from the well 10 . The absolute value of the pressure in the annulus, unless the well is blowing out, is typically less than the pump pressure measured by the sensor 54 . The scale of the pressure trace 101 is thus typically much lower than the scale of the trace 94 , meaning that the display 92 may simultaneously show two separate pressure scales. In a typical bridge plug drilling operation, the pressure trace 94 may be shown on a scale of 6000-8000 psi while the pressure trace 94 may be on a scale of 1000-3000 psi as shown by suitable lines and/or indicia (not shown) on the display 92 . The microprocessor 86 detects when pressure readings rise above or below the scale being used on the display 92 and adjusts the scale accordingly by shifting the scale up or down to make room for the trace. Similarly, when the traces 94 , 101 approach the right side of the display 92 , the pressure traces 94 , 101 are shifted to the left to provide room for additional data.
The display 92 , as shown in FIG. 5 , also preferably provides a series of boxes on one side. The box 106 conveniently shows the last pump pressure reading, the box 108 shows the last annulus pressure reading, the box 110 shows the last pressure differential reading as will be explained more fully hereinafter and the box 112 shows a voltage reading of the battery (not shown) used to operate the graphical display assembly 82 and thus suggests when the battery needs to be replaced.
An important feature of this invention is that the pressure traces 94 , 101 and the values in the boxes 106 - 112 are in real time, i.e. current time/pressure data being captured by the microprocessor 72 shows up as an addition to the traces 94 , 101 in short order, typically in a second or two. Thus, the person in charge of the operation and the person controlling the pump 46 and the injection head 44 have the capability of watching real pump and return pressures in real time and adjust operation of the pump 46 and or the coiled tubing unit 32 in response to events as they occur. Often, the trend of the pressure curves provides important clues about what is happening in the well 10 and allows the users to adjust in response to conditions as they occur and are reflected in pimp and return pressure. For example, if coiled tubing 34 is being fed into the well 10 at the depth of the sand bridge 30 , a rise in pump pressure at 114 indicates that the torque on the motor has increased and, in this context, typically means that weight is being applied to the bit 38 and the subsequent fall in pump pressure at 116 indicates that the sand bridge 38 is being washed away or being drilled.
Often, the relationship between the trends in pump and return pressure suggests an explanation for events that are occurring in the well 10 . For example, if both pressure traces 94 , 96 are falling slightly at a time when washing or drilling a plug, it likely means a lower pressure zone has been exposed. The exact meaning of any pressure changes seen on the display 92 will always depend on the context of what is happening.
As suggested previously, an important application of this invention is in operating a hydraulic motor used in a drilling application, such as shown in FIG. 2 . As mentioned previously, too much weight on the bit 38 causes increased load on the motor 36 and ultimately causes it to stall. In the prior art, when the motor is in the process of stalling, it is not apparent until the pump outlet pressure rises dramatically which occurs well after the motor has stalled. What is difficult is detecting when the motor is beginning to stall. The delay in realizing the motor has stalled is aggravated because the fluctuations in pump pressure are greater than the pressure variation that indicates the motor has stalled. For example, the fluctuations shown in FIG. 1 can easily be 300-500 psi when the average pump pressure is 7000 psi, i.e. the fluctuations can easily be in the range of 5-10% of the average pump pressure.
When a hydraulic motor goes from an idling condition to a loaded condition, there is a pressure increase on the inlet side of the motor because the motor is loaded and the force generated by the motor is converted from the pressure drop across the motor. When a hydraulic motor stalls, the pressure at the motor inlet increases further. The motor inlet pressure that signals stalling depends on the size of the motor, how much the motor is worn and a variety of other factors, many of which change while a motor is being used and before it is retrieved from a well.
Referring to FIG. 6 , a pressure trace 118 is a typical example of what happens to pump pressure as the bit 38 is lowered onto a solid drillable object such as the cement plug 28 or the bridge plug 26 . At the outset, as at 120 , the motor 36 is idling and the pump pressure is relatively stable over time. As the bit 38 is lowered onto the cement plug 28 , the pump pressure rises as shown at 122 suggesting the bit 38 is loaded and drilling on the cement plug 28 . Often, the bit 38 will drill off, i.e. it will drill faster than it is being lowered, and the pump pressure will decline slightly as shown at 124 and ultimately stabilize at 126 where the coiled tubing 34 is being lowered at the same rate as the cement plug 28 is being drilled. It will be seen that the absolute pressure in the region 126 is higher than in the region 124 indicating that the motor 36 is under load, which is what one would expect when the motor 36 goes from idling to under load.
In the event the coiled tubing 34 is lowered too rapidly, the pump pressure rises as at 128 , suggesting an imminent stalling of the motor 36 . At this time, the coiled tubing operator would manipulate the injection head 44 to either quit lowering the coiled tubing 34 or raise the coiled tubing 34 to quit drilling. The pressure necessary to stall a motor 36 of the type used on coiled tubing units 32 varies somewhat but a 200 psi pressure rise would be sufficient in many cases to stall the motor. Such a pressure rise is well below the fluctuations inherent in a high pressure multiplex pump so it would be completely masked to the coiled tubing unit operator.
In one aspect of this invention, the differential pressure is displayed in box 110 or a trace 130 of differential pressure is provided to assist in detecting an incipient stall of the motor 34 . The differential pressure displayed in box 110 or the trace 130 is a pressure differential P 2 −P 1 where P 1 is the pressure when the motor 36 is idling and P 2 is the instantaneous pressure of the motor 36 . To set the differential pressure trace 130 and to zero the instantaneous pressure differential shown in box, the user input 90 , shown as a depressible button in FIGS. 5 and 6 , is depressed at a time when the motor 36 is idling, i.e. during the interval 120 on trace 118 . This sets a value for P 1 until the next time the user input 90 is actuated.
The pressure trace 130 will be seen to be an exaggeration of the pressure trace 118 over short intervals of time unless the scale of the trace 118 is itself exaggerated. Thus, experienced users of this invention are capable of using the pressure traces 94 , 118 to determine the onset of motor stall and take appropriate action without use of the trace 130 .
Typically however, when the motor 36 begins to stall, for whatever reason but typically due to too much weight on the bit 38 , the coiled tubing operator makes decisions based on the trace 118 or the trace 130 to take weight off the bit 38 either by stopping or slowing the lowering of the coiled tubing 34 into the well or by raising the coiled tubing 34 if necessary. It will be seen that using the trace 118 or the trace 130 allows the coiled tubing operator to reduce the number of times the coiled tubing 34 is raised, thereby reducing the cycling of the coiled tubing over the wheel 42 .
This is an important advance in the operation of coiled tubing units because it reduces cycling of the coiled tubing and reducing unnecessary wear on downhole hydraulic motors thereby reducing the costs of coiled tubing operations.
Referring to FIG. 7 , there is illustrated a test of a turbine motor drilling a window in casing after a whipstock was set. This test was conducted in a test jig located at the surface so the absolute pressure values are much lower than would be expected in a downhole application where the surface pump has to overcome the hydrostatic pressure of the motive fluid. A characteristic of a turbine motor is that when it stalls, the motive fluid basically bypasses the turbine so the surface pump pressure falls off substantially. The pump was run continuously for slightly more than eight minutes.
FIG. 7 provides a single trace 132 of pump pressure and illustrates several areas 134 where the damping valves 56 of this invention have been intentionally opened so the damping system is not operative and several areas 136 where the damping valves 56 have been manipulated to provide substantial damping. It will be seen that the pressure fluctuations in the undamped areas 134 are in the neighborhood of 600 psi and the pressure fluctuations in the areas 136 are barely discernable on the scale shown and are in the range of 3-20 psi. Just after the turbine motor stalls, the pump pressure falls off. When weight is taken off the bit, the turbine begins drilling and the pressure returns to a more normal value, as shown at area 138 .
Although this invention has been disclosed and described in its preferred forms with a certain degree of particularity, it is understood that the present disclosure of the preferred forms is only by way of example and that numerous changes in the details of construction and operation and in the combination and arrangement of parts may be resorted to without departing from the spirit and scope of the invention as hereinafter claimed.
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The outlet pressure of a pump that fluctuates rapidly, as is typical of high pressure multiplex pumps, is sensed in a pressure line leading from the main flow line to a damping mechanism. The damping mechanism comprises a pair of small spaced openings, which are preferably adjustable in size. The damping mechanism is ideally a pair of needle valves placed in series so the pressure downstream of the second needle valve fluctuates considerably less than upstream of the first needle valve. The damped pressure is sensed to provide an input to real time graphs showing various pertinent pressure measurements involving the application of pressure, e.g. to monitor downhole tools in hydrocarbon wells. The downhole tools may be fluid driven motors, whipstocks, packers, wiper plugs and the like. In the case of fluid driven or mud motors, a base line pressure taken when the motor is idling is compared to the pressure when the motor is drilling to detect the onset of motor stall.
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BACKGROUND OF THE INVENTION
For years, speaker stands or "lecturns" have been constructed of metal or wood. As such, they are relatively expensive, heavy and cumbersome. Any previous attempts at constructing a speaker stand from plastic or other lightweight, moldable materials have not been successful because of their relative "flimsiness", and also because of their tendency to be top heavy.
SUMMARY OF THE INVENTION
The present invention, then, is directed to a speaker stand formed of a lightweight, moldable material such as plastic in which the individual parts are so designed, fabricated, and assembled, that the resulting structure is sturdy and resists the tendency to wobble or become loose. Further, because of the use of lightweight, moldable materials, the economies of production are so much improved that the lecturn according to the present invention realizes a superior market position.
In general, the speaker stand according to the present invention includes a base member having a substantial flat bottom surface with a cylindrical mounting hub having an axial opening therein extending upwardly from the central portion thereof, an upper support member having a substantially flat, but tilted, upper surface lying in a plane inclined with respect to the horizontal and a second cylindrical mounting hub having an axial opening extending downwardly from the central portion of the upper support member, and an elongated upright, tubular shaft member connecting the upper and lower support members and having an outer diameter substantially equal to and no greater than the axial opening in the first and second mounting hubs. The base member, upper support member, and tubular shaft member are all formed of a relatively lightweight, moldable material and the parts are bonded together to form an integral unit which is sturdy, but extremely lightweight.
It is therefore an object of the present invention to provide a speaker stand formed integrally of an extremely lightweight, moldable material.
It is another object of the present invention to provide a speaker stand of the type described in which the individual components are so molded or fabricated, that when assembled, the speaker stand takes on the appearance of an integrally molded unit and is substantially as sturdy.
Other objects and a fuller understanding of the invention will become apparent from reading the following detailed description of a preferred embodiment in view of the accompanying drawings in which:
FIG. 1 is a perspective view of the speaker stand according to the present invention;
FIG. 2 is an enlarged, longitudinal sectional view, with parts broken away, of the speaker stand illustrated in FIG. 1;
FIG. 3 is an exploded side view of the speaker stand illustrated in FIGS. 1 and 2;
FIG. 4 is a plan view of the upper support member superstructure with the top plate removed; and
FIG. 5 is a plan view of the base member superstructure with the bottom plate removed, and looking upwardly from the bottom thereof.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Turning now to the drawings, and particularly to FIGS. 1-3, there is illustrated the lecturn S according to the present invention which, in general, includes a base member 10 with a substantially flat bottom 30 and a first cylindrical mounting hub 40, having an axial opening 42 therein, extending upwardly from the central portion of the base member 10; an upper support member 50 having a substantially flat, but tilted, upper surface 70 lying in a plane inclined with respect to the horizontal, and a second cylindrical mounting hub 80, having an axial opening 82 therein, extending downwardly from the central portion of the upper support member; and an elongated, upright, tubular shaft member 90 having an outer diameter substantially equal to and no greater than the axial openings 42, 82 in the aforementioned mounting hubs 40, 80, which tubular shaft member 90 connects the base member 10 with the upper support member 50. The aforementioned base member 10, upper support member 50 and tubular shaft 90 are formed of a relatively lightweight, moldable material and are bonded together to form an integral unit.
More particularly, base member 10 in reality is formed of three separate members. The first is a molded base superstructure 12 (FIG. 5) having a generally rectangular, flat, horizontally disposed major surface 14 with a flange 16 extending downwardly, then outwardly therefrom around the peripheral edge thereof forming a shallow chamber 18 which subsequently receives a flat rectangular plate 20 therein, thereby forming the flat bottom surface 30. An inverted cup-shaped member 22 having a circular disc portion 24 with an upstanding flange 26 extending around the periphery thereof is secured to plate 20 to form a receiving cap for shaft 90 in the assembled position. The inner diameter of the flange 26 is substantially the same as the outer diameter of shaft 90 or slightly greater, so that the shaft is easily fit therein, and may be bonded thereto by a chemical bonding agent, such as butyl acetate or menthol ethyl ketone.
Meanwhile, hub 40 is formed by a cylindrical wall 28 which extends upwardly from a relatively large opening 32 in the central area of major surface 14. Cylindrical wall 28 terminates in a down turn lip 34 having an inner diameter substantially the same as the diameter of shaft 90, or slightly greater. A plurality of wedge-shaped gussets 36 are molded into the superstructure 12 between the flat major surface 14 and the wall 28 to lend support and rigidity to the base member 10. One of the edges of major portion 14 includes a cutout 38 therein which is vertically aligned with the lowermost side of upper support 12 to provide clearance for the speaker's feet.
Turning now to the upper support member 50, as illustrated in FIGS. 1-4, a molded superstructure 52 (FIG. 4) includes a generally rectangular, flat, major surface 54, so molded as to define an inclined plane with respect to the horizontal, and a raised peripheral lip 56, preferably higher at the bottom, extending upwardly from the peripheral edges of the aforementioned major surface 54 for subsequently receiving a flat rectangular plate 60 of a length and width such as to fit snugly atop the major surface 54 inside the boundary defined by the aforementioned peripheral lip 56. A shaft cap 62 in the shape of a circular disc 64 with a downwardly depending flange 66 therefrom is secured to the undersurface of flat plate 60 to form a receiving recess for the upper end of shaft 90. As is the case with cap 22, the flange 66 is of an inner diameter substantially the same as the outer diameter of shaft 90, or slightly greater. Further, it should be noted that the disc portion 64 of cap 62 is inclined with respect to the flange 66, so that, when assembled, the disc portion 64 becomes coplanar with the major surface 54. A cylindrical wall 68 extends downwardly from a relatively large opening 72 in major surface 54 and terminates in an upwardly extending lip 74 to define the second mounting hub with its axial opening 82 therein of substantially the same or slightly greater diameter than shaft 90. Reinforcing gussets 74 extend between the central surface 54 and the cylindrical wall 68 in a similar manner to that illustrated and described in connection with the base member 10.
In assembling the entire structure as illustrated in FIGS. 1-3, the upper plate 60 is assembled onto the superstructure 52 and secured thereto by a suitable bonding agent such as the butyl acetate with the receiving cap 62 extending downwardly through the central opening 72. The upper end of shaft 90 extends through the axial opening 84 into communication with the cap 62, and is similarly secured thereto. The base member 10 is assembled in the same manner with the lower plate 20 secured to the base superstructure 12 and the lower end of shaft 90 being received within the lower cap member 22 and secured thereto. So arranged, the assembled structure appears as an integral unit with considerable strength and rigidity, yet is very lightweight. While having the appearance of a one-piece molded unit, it is in reality a combination of individually fabricated parts, which can each be formed economically and assembled in a short time. The completed unit combines the features of minimizing costs and weight, while maximizing strength and rigidity.
While a preferred embodiment of the invention has been shown and described, it is obvious that various changes and slight modifications might be made without departing from the scope and intent of the present invention which is set forth in the following claims.
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A plurality of parts are so designed and fabricated from a lightweight, moldable material, such as plastic, that when assembled form an integral, sturdy speaker stand combining the features of economy, durability, and ease of handling.
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CROSS REFERENCE TO PRIOR APPLICATIONS
This application is a continuation of U.S. application Ser. No. 13/298,836 filed on Nov. 17, 2011, which is a divisional of U.S. application Ser. No. 12/886,265, filed on Sep. 20, 2010, now U.S. Pat. No. 8,116,605, which is a divisional of U.S. application Ser. No. 11/983,526, filed on Nov. 12, 2007, now U.S. Pat. No. 7,813,609, the entire disclosures of each of which are incorporated by reference herein.
FIELD OF INVENTION
This invention relates to optical imaging, and more specifically to the design of fiber optic probes for optical coherence tomography (OCT) and related imaging techniques.
BACKGROUND
Optical interference is a phenomena used widely throughout the sciences. In particular, the use of short-coherence (or ‘low-coherence’) interferometric imaging has become an important imaging modality in several fields and notably in medical applications. In interferometric imaging, light from a known and controlled optical path (the ‘reference path’) is caused to interfere with light returned from an unknown path such that information about this unknown path (the ‘sample path’) may be determined by an analysis of the resulting interferogram.
In short-coherence imaging, the interferogram contains the depth location information of structures within the sample being analyzed. Scanning short-coherence light over a sample volume to produce tomographic images is known as Optical Coherence Tomography, or OCT. In recent years, practical laser-based light sources with coherence lengths of 20 μm or less have become available, promoting the use of OCT in several fields including ophthalmology, general microscopy, cardiology and oncology.
A particular advantage of OCT is its inherent compatibility with fiber optics making it a nearly ideal imaging modality for non-invasive or minimally invasive medical procedures.
Central to all OCT implementations is the requirement that the lengths of the sample and reference paths be matched to ensure the interference effect being recorded corresponds to a desired scan region within the sample. In the case of relatively long optical catheters required in many procedures (approximately 1.5 to 2 meters is common) this requirement for matching the path lengths may become difficult to achieve, especially when many practical implementations of OCT require matching on the millimeter scale. Furthermore, the very thin fibers used in these catheters can easily stretch or contract several millimeters during use.
When using OCT in any application, the optical ‘zero-point’ is critical. This defines where, in the image space, the so-called reference plane exists. By convention, surface planes are in the x-y plane, and the depth occurs along the z-axis. In a microscope application for example, it may be beneficial to set the zero point at the surface of the microscope slide, so specimens can be measured against this known surface. In a catheter inserted into a bodily lumen, the most useful reference plane is the outer surface of the catheter tip itself, and all distances are measured outward from this location.
For a rotating catheter, the x-y-z space is best represented in polar coordinates (angle and radial distance). Hence the z-axis becomes the radial distance from the center. Practically, setting a match point means that the optical length from the chosen reference plane in the sample is equal to the primary optical length in the reference arm. The high speed changing of the reference arm length in scanning represents only a small variation on the primary length. Because OCT penetrates tissue only a few millimeters at most, the scan is practically limited to typically 1-5 mm, whereas the actual lengths of the sample and reference arms may be several meters.
For example, in the case of optical catheters used in cardiology, the instrument itself will be located outside the nominal ‘sterile field’ surrounding the patient, the catheter itself will be inside this field, and an umbilical will be used to join the two. The total optical length of the sample arm (catheter plus umbilical) can easily approach 5 meters, which will also be the primary length of the reference arm. Since scanning will be perhaps 5 mm, this represents 0.1% of the total length. Measurement accuracy is required to be 0.1 mm or better in this application. Since it is not cost-effective to control the lengths of each optical fiber within the catheter and umbilical to sub-millimeter dimensions, most design approaches use an adjustable reference path within the optical imaging equipment to adjust to each catheter as it is used.
However, a medical application may use many disposable catheters per day; all interfaced to the same imaging equipment. Thus, while the primary path length adjustment can work quite effectively, it usually requires an initial adjustment by a skilled operator who understands the optical reflection pattern or ‘signature’ of the catheters that will be recorded by OCT to determine how to adjust the reference path to coincide with the outer surface of the catheter tip. Again, the adjustment of the image zero-point, or reference plane location is performed by adjusting the primary path-length of the reference arm. This adjustment is often termed ‘z-offset’ of the reference arm and is controlled via a motor, called simply the z-offset motor. By convention, the instrument z-offset is zero when the sample arm length (catheter) manufactured exactly as designed; is negative when the catheter is too short; and positive when the catheter is too long.
These optical catheters typically have a lens and reflector structure placed at their distal tip to focus and direct the light for scanning purposes. The light typically propagates through one or more transparent sheaths that comprise the catheter outer structure. Each of the interfaces can and will cause a reflection that will be detected by OCT. Hence, it may be challenging to determine which of those reflections corresponds to the desired optical reference point (‘zero-point’) of the system. Since measurements are made based on this zero-point setting, setting it correctly can have significant importance in medical applications. Furthermore, because there may be several closely spaced and similar intensity reflections, the use of software to detect the proper zero-offset (‘z-offset’) is extremely problematic and unreliable.
As noted, the optical fiber can stretch significantly on these scales when the catheter is advanced or retracted. For example, using the known yield strength of standard optical fibers used in OCT, and the catheter length, it is easy to show that 10 mm of stretch can occur before the fiber breaks. Typical forces encountered in real situations will only cause a 1 mm stretch or less, but many medical measurements require accuracy of ¼ millimeter or better.
Therefore, a simple, cost effective method for reliably determining the optical match point (‘zero-point’) of the catheter is needed. Furthermore, this method should be compatible with real-time video rate imaging so that the zero-point can be tracked as the catheter is maneuvered, retracted or advanced. The present invention addresses these issues.
SUMMARY OF THE INVENTION
In one aspect, the invention relates to fiber optic imaging probe having an elongated section and a proximal and a distal end, the probe comprising a thin controlled optical scattering material applied to the distal end.
In another aspect, the invention relates to an optical element. The optical element includes a membrane having a first surface and a second surface. The membrane includes a polymer and at least one backscattering element for controlled optical back-scattering disposed therein. Further, the membrane allows transmission of substantially undistorted imaging light.
The aspects of the invention described herein can include further embodiments. For example, the optical element can further include a plurality of back-scattering elements wherein the at least one back-scattering element and each of the plurality of back-scattering elements is a particle having a particle dimension, the plurality of back-scattering elements disposed within the polymer. In one embodiment, the membrane is shaped to form a curved surface suitable for engulfing, surrounding, enveloping or otherwise covering an optical fiber endface or micro-lens.
The particle dimension, in some preferred embodiments; is less than about 1.5 μm. Further, the particles can include titanium, zinc, aluminum, and/or other materials suitable for scattering light. The plurality of scattering elements can have a concentration of about 0.1% doping concentration by volume. The optical element can further include an elongate member, wherein the membrane is shaped to form a sheath within which the elongate member is disposed to form a portion of a probe tip.
In another aspect, the invention relates to an imaging probe. The probe includes an elongate section having a first end and a second end; the second end forming a probe tip capable of intra-lumen imaging, the probe tip comprising a scattering material, the elongate section adapted to transmit light reflected by the scattering material to the first end of the elongate section.
In one embodiment, the elongate section is an optical fiber. The elongate section can be a sheath. Also, the probe can further include an optical fiber disposed within the sheath. The scattering material can include a plurality of light scattering particles dispersed in a matrix. The scattering particles can include titanium and/or other materials known to scatter light. Also, the matrix can include polyethylene terephalate and/or other polymers.
In another aspect, the invention relates to a lens assembly. The lens assembly includes a micro-lens; a beam director in optical communication with the micro-lens; and a substantially transparent film. The substantially transparent film is capable of bi-directionally transmitting light, and generating a controlled amount of backscatter. In addition, the film surrounds a portion of the beam director.
In one embodiment of an aspect of the invention, the controlled amount of backscatter is in an amount of light at least sufficient to generate a reference point in an imaging system for calibration of at least one imaging system parameter. The substantially transparent film can also include a plurality of scattering particles. The micro-lens can be in optical communication with an optical fiber. Further, the substantially transparent film can be shaped to form an imaging probe tip. Also, the probe tip can be used for optical coherence tomography imaging.
In still another aspect, the invention relates to a method of calibrating an optical coherence tomography system. The method includes generating scan data in response to light reflected from a sample, the reflected light passing through a bi-directional substantially transparent optical element; generating reference data in response to scattered light reflected from a scattering element disposed within the bi-directional substantially transparent optical element; and calibrating the optical coherence tomography system to determine the relative position of subsequent scans in response to the reference data.
In one embodiment of an aspect of the invention, scan data includes a set of angles and a set of radial distances. Further, the reference data can include a set of angles and a set of radial distances. The step of calibrating can include searching for a ring pattern within the reference data.
In yet another aspect, the invention relates to a method of fabricating an optical element. The method includes selecting a membrane material suitable for intra-lumen use in an animal; selecting a dopant suitable for dispersion in the membrane material, the dopant adapted to scatter light in response to an optical source; determining a dopant volume concentration such that a radial scan of a doped membrane generates a defined pattern; doping the membrane with the selected dopant to substantially obtain the determined dopant volume concentration; and shaping the membrane for intra-lumen use in an animal.
In on embodiment, the membrane includes polyethylene terephalate. The dopant volume concentration can include about 0.1% doping concentration by volume. The selected dopants can include an oxide. Further, the defined pattern can be selected from the group consisting of a ring and a spiral.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of an OCT system suitable for use with the optical probe of the invention;
FIG. 2 is a schematic diagram of an optical catheter system, suitable for use with OCT imaging in coronary arteries;
FIG. 3 is a schematic diagram of the optical fiber tip, with micro lens and protective cover;
FIG. 3 a is a photomicrograph of an embodiment of the probe shown schematically in FIG. 3 .
FIGS. 4 a and 4 b depict an image taken with a doped plastic lens cover and an undoped plastic (such as PET) cover, respectively;
FIG. 4 c depicts an OCT image in which an over-concentration of the dopant TiO 2 is used and the resulting clumping leads to optical shadowing;
FIG. 5 is a flow chart of an embodiment of an algorithm used to detect the PET ring;
FIG. 6 is a flow chart of an embodiment of an algorithm used to set the location of the PET ring;
FIG. 7 depicts an image of a coronary artery made using the components in FIGS. 1 and 2 in which the zero-point offset is set correctly;
FIG. 8 depicts an image of a coronary artery made using the components in FIGS. 1 and 2 in which the zero-point offset is set incorrectly (the zero-point is too short and has been moved within the optical fiber causing the image to expand away from the center);
FIG. 9 depicts an image of a coronary artery made using the components in FIGS. 1 and 2 in which the zero-point offset is set incorrectly (the zero-point is too long and has moved to a point outside the fiber, causing the image to contract towards the center); and
FIG. 10 depicts a magnified OCT image of a catheter center showing characteristic ring reflections according to an embodiment of the invention
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
In brief overview and referring to FIG. 1 , a generalized OCT interferometer 10 is shown which is suitable for use with the catheter imaging system of the invention. A light source 14 , such as a diode laser, produces short-coherence length light that passes by way of an optical fiber 18 into an optical fiber coupler 22 . Light entering the coupler 22 is the split along two optical fiber paths 26 and 30 . One path 26 terminates at a movable reflector 34 , while the other enters a probe 38 and is emitted toward an object of interest 42 .
Light reflected by the movable reflector 34 passes back along optical fiber 26 to the coupler 22 . Similarly light reflected by the object of interest 42 passes back along optical fiber 30 to the coupler 22 and combines with the light reflected by the movable reflector 34 to form an interference pattern. This combined light passes through optical fiber 46 and is detected by a detector 50 . The output signal from the detector 50 is processed by electronics 54 and an image formed on display 58 .
An example of an imaging catheter suitable for use as the probe in FIG. 1 is shown in FIG. 2 . In this embodiment, the imaging probe 38 is the tip of a coronary vessel imaging catheter. A connector 62 attaches to the optical coupler 22 of the system of FIG. 1 . The optical fiber 30 enters a y-body connector 66 attached to a balloon catheter 70 . This catheter 70 includes a flushing port 74 and a balloon inflation port 78 as well as a flush exit 82 .
FIG. 3 depicts an embodiment of the image wire tip of the probe 38 . The optical fiber 30 terminates in a micro-lens assembly 86 which focuses the light at a distance from the micro-lens assembly 86 . Light emitted from the micro-lens assembly 86 is reflected by a beam deflector 90 so to as to pass at substantially right angles to the optical axis of the fiber 30 . The entire fiber assembly is covered by a protective transparent sheath 94 sealed at one end 98 as discussed below.
As explained in U.S. Pat. No. 6,891,894, herein incorporated by reference, a particularly advantageous fiber lens design uses total internal reflection from a silica-air interface to provide the needed radial scan inside a lumen, such as an artery, by simply rotating the fiber. Since the total internal reflection depends on the refractive index mismatch between the silica and air, direct immersion in a fluid will eliminate this reflection and the light will propagate forward instead, destroying the ability to take useful radial scan. As shown in the '894 patent and in FIGS. 3 and 3 a , the air-silica interface can be preserved by using a clear protective cover 94 adhered directly to the fiber lens assembly. Such a cover can be made preferably from a heat-shrinkable material such as polyester (Polyethylene Terepthalate, or PET). PET is widely used in industry and medical devices and has good biomedical compatibility properties.
Such a PET cover has inherent low back-reflection, so in its usual format it is unsuitable for the purpose of providing a fixed reference reflection. However, with care, dopants can be added to the raw PET material (before the tube shape is formed) increasing the native back-reflection.
Several materials exist as a suitable dopant. In particular titanium dioxide (TiO 2 ) is advantageous. TiO 2 is used in many paint formulations due to its excellent light scattering properties. Further it is inert and can be made in bulk. The particle size can be made much smaller than the optical wavelengths of interest (nominally 1.3 μm), making the scattering ‘Rayleigh’ in nature. Thus the outgoing and returning light wavefronts are not appreciably disturbed, thereby minimizing any potential image degradation at sufficiently low concentrations of dopant.
A key step in the creation of the material is uniformly mixing TiO 2 particles in the raw PET such that, when drawing the PET into tubing, the correct concentration is realized with high uniformity. In addition, because OCT imaging has tremendous sensitivity and large dynamic range (typically 100 dB of sensitivity and >60 dB of dynamic range can be achieved in practical instruments) care must be used to calculate then achieve the optimal doping level of TiO 2 in the material.
Basic scattering theory can be used to arrive at a doping concentration in the material. In a typical OCT image in the coronary arteries, the minimum noise in the instrument is about −100 dB. That is, about 1 ten-billionth of the optical output power applied to the object of interest and a typical image has approximately 40 dB of useful dynamic range. The image processing electronics and software are optimized for this range, so the probe reflector element should be optimized to be near the maximum detectable peak of the image intensity, which is about −60 dB (−100+40). This means that the probe reflector should be the brightest object in the image.
As described herein the probe reflector element can include, but is not limited to, a membrane, a film, a cap, a cover, or other material, in some embodiments, the reflector element is flexible or inflexible. The reflector element can be shaped in various geometries, such that portions of the reflector are curved, planar, or substantially planar.
Basic scattering theory for particles and classic radar cross-section theory estimates that the fraction of light reflected from a single TiO 2 particle is given by the expression:
L
R
=
σ
b
V
i
l
c
Δ
Ω
where L R is the return light fraction, σ b is the scattering cross-section (calculated from standard MIE theory), V i is the volume of the particle, l c is the interaction length (from Radar theory), in this case the coherence length of the OCT light, and ΔΩ is acceptance angle (solid angle) of the micro-lens. Thus, for a particle size of roughly 45 nm with a scattering cross section of approximately 4.26×10 −7 μm 2 , and light having a coherence length of about 15 μm irradiating the particle through a micro-lens having a solid angle of ˜0.004, the reflected light fraction, L R , is about 0.006, or −32 dB.
Therefore the total light returned from the probe reference reflector element material should be equal to the single particle light fraction times the volume fraction (doping concentration). Because this should be equal to about −60 dB (from above), a reduction of −30 dB (or 0.001) is required. Therefore, the volume fraction should be about 0.001, or about 0.1% doping concentration by volume. This should result in a strong, but not overpowering reference reflection by the TiO 2 particles.
When the zero point offset position is stable, the doped PET material produces a consistent, bright ring in the image as shown in FIG. 4 a , as compared to an undoped cover FIG. 4 b . When the zero point offset position is unstable, either by purposely modifying the reference path length or through stretching or compressing of the fibers during normal use, the ring is more of a spiral shape. If the concentration of TiO 2 particles is too high, the particles cast shadows due to clumping as shown in FIG. 4 c . In one embodiment, the probe reflector element is a membrane that is capable of transmitting substantially undistorted imaging light. The term “substantially undistorted imaging light” means light that is suitable for generating an image of a sample or a sample element.
The captured data in ‘raw’ format is a series of radial scans, each occurring at evenly spaced angles, very much like the spokes in bicycle wheel. The raw data is stored simply in a conventional array memory format, where columns represent angles, and each row is a particular radial distance. Hence, the image of a perfect circle stored in memory would occur along the same row for each column, i.e. a straight line with zero (flat) slope. A spiral pattern is stored as a straight line with a slope, positive if the spiral is expanding, negative if the spiral is contracting.
Hence the signal from the PET material produces a line in the image that may have a flat, positive or negative slope depending on whether the optical path length is constant, increasing or decreasing. The magnitude of the slope is then proportional to the rate of change of the fiber path length in either direction due to stretching or shrinking. Because the zero point offset position is now detectable, a software algorithm can be used to isolate the PET ring by taking advantage of its bright reflection, known thickness and expected straight line representation in memory.
The basic steps of the algorithm are shown in FIG. 5 . The OCT image is obtained (Step 1) and first analyzed on a statistical basis. This analysis calculates the number of pixels for each given intensity value. The histogram is then used to generate a “Global Threshold” value to separate the foreground tissue from background noise (Step 2). Because the image intensity will eventually fall to the background noise level, the intensity at large radial distances can be used to estimate the overall ‘noise-floor’ of the system. This value is then be used to produce a binary image (Step 3). Intensity values above the threshold are set to one; those below the threshold are set to zero. By analyzing the binary image and not the input OCT image, the dependence on the absolute level of the doped PET reflection is minimized.
Once the binary image is available, it is filtered with a one dimensional spatial filter (Step 4) that is designed to have peak response for a signal with thickness similar to the known PET layer thickness and adjacent black space. As shown in the figure, the influence of the tissue is greatly minimized by the spatial filter, while the PET ring is preserved.
The next step in the process (Step 5) is to average all of the scan lines in each quadrant of the filtered binary image together to produce one representative scan line per quadrant. This means, in stored memory, the columns are divided into four equal groups, and for each group, all columns are averaged together across rows to produce one representative column for each of the four 90 degree quadrants of the original image. This process serves to emphasize image content that is concentric or nearly concentric. The average is performed on a quadrant basis, as opposed to the full 360 degrees, so that the PET signal from a moving reference path (which would be spiral shaped) is not lost in the summation process. The resulting four average lines are each smoothed with a simple boxcar filter, and the brightest three peaks on each are located.
Finally, in the next step (Step 6) the peak from each quadrant's average line is selected that together produces the best ring. A recursive algorithm is used to analyze each potential group by first computing the sum of the four points and then the mean square error (MSE) of a line fitted to the points using a least squares fit algorithm. The resulting MSE is combined with the sum of the four points to form a score. This score serves to emphasize potential rings that are bright (larger sum) and flat (smaller MSE). The group with the largest score is chosen as the winner and its sum is compared to a cutoff to determine if the result is valid.
In operation, when a new image catheter is connected to the system, an initial coarse calibration is performed by rotating the fiber and adjusting the reference path control motor as shown in FIG. 6 . The z-offset motor in the reference arm is initially swept at high speed (Step 10) between its limits while searching for the PET ring. Once the ring is found, the motor speed is slowed (Step 12) and the PET image is moved close to its desired location zero-point, here termed the “Loose Range”).
Further, once within the loose range, the motor is stepped (Step 14) until the PET image is in its final allowed range (the “Tight Range”). During live scanning the Z-Offset may drift slightly, resulting in the PET moving outside of the tight range. When this occurs, the motor is reactivated to step the PET back into the tight range. The tight range allowance is a balance set by the desired measurement accuracy and the minimization of constant z-offset motor movements
During real-time imaging, the PET ring, as defined by the least squares fitted line of the winning group, is displayed at a fixed location (radius) on the screen based on the known physical location of the PET in the micro-lens assembly. The z-offset of each image frame is adjusted in or out so that the PET ring ends up at the desired location.
The final result is that the Z-Offset corrected image is displayed on the screen and stored in the saved image files, allowing correct clinical measurements to be performed in a straightforward manner. FIG. 7 is an OCT image of a coronary artery in which the z-offset is set correctly. The vessel diameter is thus correctly measured as 2.55 mm. FIG. 8 is an OCT image of a coronary artery in which the z-offset is set incorrectly such that the z-offset is positioned within the lens assembly. The vessel diameter is thus incorrectly measured as 2.97 mm.
FIG. 9 is an OCT image of a coronary artery in which the z-offset is set incorrectly such that the z-offset is positioned outside the protective PET cover. The vessel diameter is thus incorrectly measured as 2.00 mm. Thus, the present invention provides a method for determining the equalization of the reference and sample paths in an OCT interferometer, to thereby provide an accurate measure of the objects of interest.
FIG. 10 is another OCT image generated in accordance with aspects of the invention. Specifically, it is a magnified OCT image of a catheter center showing characteristic ring reflections arising from the micro-lens PET layer (innermost) 100 and the image wire plastic sheath (middle) 102 . The outer ring 104 corresponds to the inside wall edge of the plastic tubing into which the image wire was inserted to generate the image depicted in FIG. 10 . However, due to thickness of the tubing, the outer wall edge is not seen in the image.
In FIG. 10 , the PET ring is generated using standard, un-doped PET. As shown, the image wire is pressed against the side of the tubing thereby causing the third outer ring 104 to be non-concentric.
It should be understood that the above-described embodiments and the following examples are given by way of illustration, not limitation. Various changes and modifications within the scope of the present invention will become apparent to those skilled in the art from the present description.
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In part, the invention relates to a lens assembly. The lens assembly includes a micro-lens; a beam director in optical communication with the micro-lens; and a substantially transparent film. The substantially transparent film is capable of bi-directionally transmitting light, and generating a controlled amount of backscatter. In addition, the film surrounds a portion of the beam director.
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BACKGROUND OF THE INVENTION
The present invention relates to a method in the regulation of a multi-layer headbox of a paper machine or board machine. By means of the method and the device in accordance with the invention, it is possible to reliably act upon the grammage profile of the paper across the width of the paper web and also to act upon the fiber orientation profile in the paper web across the width of the paper web. The invention also relates to a multi-layer headbox of a paper machine or board machine.
In a multi-layer headbox, pulps of different sorts in the vertical direction are fed in different layers. One or both of the faces of the paper or board formed out of the jet of the headbox are made representative by using, e.g., high-cost and bleached pulp with a high content of fillers. In a three-layer structure, the middle layer is used to constitute the strength and rigidity of the paper/board, whereas the surface layers hide the less expensive and coarser raw-material in the middle of the structure.
In a multi-layer headbox, when the grammage is regulated conventionally by profiling the shape of the slice, all the layers are affected at the same time, including the covering surface layers. In such a case, the coverage by the surface material is changed in the regulated area and leaves a striped appearance in the product. The profile-bar construction produces turbulence in the jet and deteriorates the purity of the layers.
As is known from the prior art, the direction of the discharge jet of the pulp suspension discharged out of the headbox should differ from the machine direction as little as possible. A directional angle of the discharge jet that differs from the machine direction, which produces distortion of the fiber orientation, has a clear effect on the quality factors of the paper, such as the anisotropy of strength and stretch. The level and variation of anisotropy in the transverse direction also affect the printing properties of paper, such as moisture expansion. In particular, it is an important requirement that the main axes of the directional distribution, i.e. orientation, of the fiber mesh in the paper coincide with the directions of the main axes of the paper and that the orientation is symmetric in relation to these axes.
At the edges of the pulp-flow duct in the headbox, owing to the vertical walls, there is a higher friction. This edge effect produces a very strong linear distortion in the profile. Profile faults in the turbulence generator of the headbox usually produce a non-linear distortion in the profile inside the lateral areas of the flow ducts.
Attempts are made to compensate for an unevenness of the grammage profile arising from the drying-shrinkage of paper/board by means of a crown formation of the slice, so that the slice is thicker in the middle of the pulp jet. It is a phenomenon in the manufacture of paper that when the paper/board web is dried, it shrinks in the middle area of the web to a lower extent than in the lateral areas of the web. The shrinkage is typically in the middle are of the web from about 1% to about 3% and in the lateral areas of the web from about 4% to about 6%. The shrinkage profile produces a corresponding change in the transverse grammage profile of the web so that, owing to the shrinkage, the dry grammage profile of a web whose transverse grammage profile was uniform after the press is changed during the drying so that, in both of the lateral areas of the web, the grammage is slightly higher than in the middle area. As is known from the prior art, the grammage profile has been regulated by profiling the thickness of the jet, either by means of a profile bar construction or by regulating the shape of the discharge duct so that the thickness of the jet is regulated to be larger in the middle area than in the lateral areas of the web.
By means of this arrangement, the pulp suspension is forced to move towards the middle area of the web. However, this circumstance affects the deviation-angle profile of the direction of the discharge jet, which profile further determines the distortion profile of the fiber orientation. The main axes of the directional distribution, i.e. orientation, of the fiber mesh should coincide with the directions of the main axes of the paper, and the orientation should be symmetric in relation to these axes. In the regulation arrangement that profiles the thickness of the jet, a change in the orientation is produced as the pulp suspension flow receives components in the transverse direction.
Regulation of the lip of the headbox also produces a change in the transverse flows of the pulp jet even though the objective of the regulation is exclusively to affect the grammage profile, i.e. the thickness profile of the pulp suspension layer that is fed. Thus, the transverse flows have a direct relationship with the distribution of the fiber orientation.
In the prior art, reference is also made to Finnish Patent Application No. 912230 which describes a headbox that has been divided across its width into compartments by means of partition walls and in which, in an individual compartment, there is at least one inlet duct for the passage of a component flow. Moreover, in the device described in FI 912230, a mixer is connected in front of the individual inlet duct by whose means the pulp suspension ratio can be regulated. In the device of FI 912230, it has, however, not been possible to adequately regulate the mixing ratio without a change in the flow quantity. A detailed device has not been described for carrying out the regulation nor is the device related to a multi-layer headbox.
OBJECTS AND SUMMARY OF THE INVENTION
Accordingly, it is an object of the present invention to provide novel solutions for the problems discussed above.
It is an object of the present invention to provide a new and improved method and device by whose means the pulp suspension flow discharged out of a multi-layer headbox can be regulated without a profile bar.
It is another object of the present invention to provide a new and improved method and device by whose means it is possible to regulate the consistency of the flow locally and the pressure level of said consistency-regulated flow and, thus, the overall flow quantity or rate and the flow velocity while the mixing ratio remains at a regulated, invariable value.
It is still another object of the present invention to provide a new and improved method and device by whose means it is possible to control the grammage profile of the paper/board web reliably across the entire web width, and favorably also control the fiber orientation profile of the paper/board web across the entire web width in the layer to which the regulation of the grammage is applied.
In accordance with the invention, the grammage profile is affected by regulating the pulp flow that forms one layer. The grammage profile of the remaining layers of pulp flow in the multi-layer headbox are not required to be regulated.
In the method in accordance with the invention, the flow of a pulp suspension that forms one of the layers of the web is regulated by regulating the component subflows that constitute this flow and regulating the concentrations of the component subflows independently from one another. By means of this specific regulation applied to the particular layer, the total flow of the pulp suspension leaving the headbox is regulated.
In the multi-layer headbox in accordance with the invention, for the formation of a second pulp suspension, in addition to a first pulp suspension which is directed straight from the inlet header to the slice, the device comprises a source for the introduction of a first subcomponent flow, preferably an inlet header, and at least one additional source for the introduction of a second subcomponent flow, preferably also an inlet header. A mixer unit is provided in which the combination of the subcomponent flows takes place so that, when one subcomponent flow is increased, the other subcomponent flow is reduced by the corresponding amount, and vice versa. The combined flow (subflow), which remained invariable during the regulation of the mixing ratio, is passed into the discharge duct of the headbox. The flow of the pulp suspension from the slice of the headbox is composed of several adjacent component subflows, which have been introduced at different points across the width of the multi-layer headbox, and the concentrations of these flows are regulated across the width of the web. The flow of the pulp suspension that flows out of the multi-layer headbox is thus regulated by means of the regulation of the single layer.
In a preferred embodiment of the invention, two subcomponent flows are introduced into the mixer, and the mixing ratio of these two subcomponent flows is continuously regulated so that when the throttle of the pulp flow or 0-water flow in one subcomponent-flow duct is increased, the throttle of the other subcomponent flow is reduced, and vice versa. Thus, in the regulation, the concentration of the overall pulp flow departing from the mixer is affected continuously and, yet, the quantity or rate of the overall flow is kept invariable.
Thus, it is possible to add to the pulp flow, for example, water alone, i.e. 0-water, or a diluted pulp suspension whose concentration differs, on the whole, from the concentration of the other component subflow. The combined flow constitutes the web layer.
In the prior art devices, the grammage profile was altered by acting upon the thickness profile of the jet discharged out of the headbox. However, in the device in accordance with the invention, a profiling throttle is not necessarily needed because the fiber orientation profile is regulated by means of local flows passed into different positions of width in the headbox.
In the device in accordance with the invention, the multi-layer headbox comprises separate blocks across the width of the multi-layer headbox. In these blocks, it is possible to regulate the consistencies of the flows to a desired level. For example, when the flow in the middle layer is regulated, by means of the flow it is possible to correct a fault in the grammage profile occurring in a certain width position of the web. Thus, at a specific position in the width of the headbox, it is possible to introduce a pulp suspension thicker than average or a pulp suspension more dilute than average, depending on the measured grammage profile error, so as to correct the grammage profile error. However, it is essential in the regulation of the grammage profile that, the flow quantity of the combined flow is kept invariable. Thus, during the regulation of the consistency, changes are not produced in the overall flow-velocity profile of the pulp suspension in the headbox. By means of the width-specific flows in the headbox, and by means of regulation of the consistency of these flows, the consistency of the pulp suspension is affected only at a certain, desired position of width, and thus, by means of each flow, faults occurring in the grammage profile may be corrected.
Also, in the device and method in accordance with the invention, it is possible to regulate the fiber orientation of the flow discharged out of the headbox by regulating the pressure profile of the flow to thereby regulate the velocity profile. This takes place by, in a certain layer, regulating the flow quantity of each flow along the width of the headbox independently from one another. Thus, when the fiber orientation profile is desired to be corrected, the flow velocity profile coming out of the pipe system of the turbulence generator is affected locally in the direction of width of the web. In addition, at a certain position of width of the web, locally the pressure level and thereby the flow velocity and further the flow quantity are increased or, if necessary, reduced. In this manner, it is possible to act upon local profile faults occurring in the fiber orientation of the web.
In the following, the invention will be described in detail with reference to some exemplifying embodiments of the invention illustrated in the figures in the accompanying drawing, the invention being by no means strictly confined to the details of the embodiments.
BRIEF DESCRIPTION OF THE DRAWINGS
The following drawings are illustrative of embodiments of the invention and are not meant to limit the scope of the invention as encompassed by the claims.
FIG. 1 is a sectional view of a multi-layer headbox of a paper machine in accordance with the invention.
FIG. 2A is a sectional view taken along the line I--I in FIG. 1.
FIG. 2B is a sectional view taken along the line II--II in FIG. 1.
FIG. 2C is a sectional view taken along the line III--III in FIG. 1.
FIG. 2D is a sectional view taken along the line IV--IV in FIG. 1.
FIG. 3 is a partial illustration of principle of a mixer unit by whose means a fault in the grammage profile and a fault in the fiber orientation profile can be corrected locally in the direction of width of the web.
FIG. 4A is an illustration of principle of a first position of flow regulation.
FIG. 4B shows a second position of flow regulation.
FIG. 4C shows a third position of flow regulation.
FIG. 5A is a sectional view of the mixer unit in accordance with the invention showing an embodiment of a mixer unit which corresponds to the illustrations of principle in FIG. 3 and in FIGS. 4A, 4B and 4C.
FIG. 5B is an illustration in the direction K 1 indicated in FIG. 5A.
FIG. 5C is an illustration in the direction K 2 indicated in FIG. 5A.
FIG. 5D is an illustration in the direction K 3 indicated in FIG. 5A.
FIG. 5E is an axonometric view of the distributor part of the mixer unit shown in FIGS. 5A-5D.
FIG. 6A is a sectional view of a second embodiment of the mixer unit in accordance with the invention, wherein the flow into the inlet chamber of the mixer unit is distributed by means of a separate tumbler piece which is placed in different closing positions in relation to the inlet openings, in which case, when one inlet opening is being opened, the other inlet opening is closed by a corresponding amount.
FIG. 6B is a sectional view taken along the line V--V in FIG. 6A.
FIG. 7A shows an embodiment of the invention in other respects corresponding to FIGS. 6A,6B, except that in this embodiment the pressure level of the departing flow can also be regulated.
FIG. 7B is a sectional view taken along the line VI--VI in FIG. 7A.
DETAILED DESCRIPTION OF THE INVENTION
FIG. 1 shows a multi-layer headbox in accordance with the invention in connection with a twin wire former. Of the former, FIG. 1 shows a pair of breast rolls 10 and 11 and forming wires 12 and 13 running over them and defining a forming gap G therebetween. A discharge duct 14 of the headbox comprises flaps 16a 1 ,16a 2 , . . . and out of the discharge duct 14 of the headbox, the pulp suspension jet is fed through the slice 15 into the forming gap G defined by the wires 12 and 13.
Proceeding in the flow direction E of the pulp suspension, the headbox comprises inlet headers 100,110,120,130, distributor manifolds, a turbulence generator 19, and a discharge duct 14. The discharge duct 14 isdefined by a stationary lower-lip wall 20 and by an upper-lip wall 21 pivoting around a horizontal articulated joint G.
In the multi-layer headbox, a first pulp suspension component flow M 1 is passed out of the inlet header 100 through the distributor manifold 101into an intermediate chamber J 1 . The pulp suspension component flow isthen passed further to the throttle 102 and from the throttle 102 to the turbulence generator 19, specifically into turbulence tubes 19a 1 in the turbulence generator 19.
Similarly, a second pulp suspension component flow M 3 , whose composition may be the same as that of the first pulp suspension componentflow M 1 or different, is brought from the inlet header 110 through thedistributor manifold 111 into an intermediate chamber J 2 . The pulp suspension component flow M 3 is then directed through the throttle 112 to the turbulence generator 19 into its turbulence tubes.
The third component subflows Q 3 .1, Q 3 .2, . . . , Q 3 .n of a third pulp suspension component flow M 2 is composed of subcomponent flows Q 1 .1, Q 1 .2, . . . , Q 1 .n and Q 2 .1, Q 2 .2, . . . , Q 2 .n. Each subcomponent flow Q 1 .1, Q 1 .2, . . . , Q 1 .n is brought from the inlet manifold 120 and passed through the respective distributor pipes 23a 1 ,23a 2 , . . . into its own, separate mixer unit 22a 1 ,22a 2 , . . . , 22a n in the direction of width of the headbox. From the other inlet header 130, the second subcomponent flow Q 2 .1, Q 2 .2, . . . , Q 2 .n of the third pulp suspension component flow is passed through respective distributor pipes 24a 1 ,24a 2 , into the mixer unit 22a 1 ,22a 2 , . . . , 22a n . In the mixer units 22a 1 ,22a.sub. 2, . . . , 22a n , the subcomponent flows Q 1 .1,Q 1 .2, . . . , Q 1 .n and Q 2 .1, Q 2 .2, . . . , Q 2 .n are mixed together to form a combined flow Q 3 which forms a pulp suspension component flow M 2 (Q 1 .1 +Q 1 .2 ; Q 2 .1 +Q 2 .2). The pulp suspension component flow M 2 is passed, as illustrated in FIG. 1, as the middle flow into the intermediate chambers 28a 1 ,28a 2 . . . , which have been divided into compartments in the direction of width, or into pipes, and further into the turbulence generator 19 into the tubes 19a 2 of the turbulence generator placed in a corresponding relative height position, i.e., at substantially the same level.
The discharge duct 14 comprises flaps 16a 1 ,16a 2 , . . . , 16a n . When the pulp suspension component flows M 1 , M 2 and M 3 are passed in the manner described above, having been divided intoblocks in the vertical direction, the mixing together of the pulp suspension component flows is prevented. In addition, by means of the pulpsuspension component flows M 1 , M 2 and M 3 , the web layers T 1 , T 2 and T 3 are formed. Further, in accordance with the present invention, the component subflows Q 3 .1,Q 3 .2, . . . , Q 3 .n of the middle pulp suspension component flow M 2 are regulated in the direction of width of the paper machine by means of the mixer units 22a 1 ,22a 2 , . . . , 22a n . As a result, on the whole, the flow of the overall pulp suspension M departing from the multi-layer headbox is regulated by means of the regulation of the middle layer (M 2 ). The concept and the composition of the pulp M 2 differ from the composition and the concept of the pulp M 1 of the surface layer and preferably also from the composition and the concept of the pulp M 3 .
Within the scope of the invention, it is, of course, possible that the multi-layer headbox comprises means for the formation of two web layers only or means for the formation of more than three web layers.
Within the scope of the invention, an embodiment of the invention is, of course, also possible in which intermediate chambers are not needed for the pulp flows M 1 and M 3 . In such a case, the pulps M 1 and M 3 are made to flow out of their inlet headers directly through pipesinto the turbulence generator 19.
FIG. 2A is a sectional view taken along the line I--I in FIG. 1. As shown in FIG. 2A, the pulp M 1 is passed out of the inlet header 100 into distributor pipes 101a 1 ,101a 2 , . . . , 101a n and further into the intermediate chamber J 1 . From the chamber J 1 , the pulp M 1 is passed through respective throttles 102a 1 ,102a 2 , . . . , 102a n and further into the turbulence generator 19 into its turbulence tubes 19a 1 . From the turbulence tubes, the pulp M 1 flows into the discharge duct 14 and is not mixed with the other pulp layers M 2 ,M 3 .
FIG. 2B is a sectional view taken along the line II--II in FIG. 1. The sectional view of FIG. 2B corresponds to the sectional view in FIG. 2A because the arrangement of introduction of the pulp M 3 is similar to that of the pulp M 1 . The pulp M 3 is passed from the inlet header110 into the distributor pipes 111a 1 ,111a 2 , . . . and further into the intermediate chamber J 2 . From the chamber J 2 , the pulp M 3 is passed through the throttles 112a 1 ,112a 2 , . . . and further into the turbulence generator 19 into its turbulence tubes 19a 3 and then into the discharge duct 14.
FIG. 2C is a sectional view taken along the line III--III in FIG. 1. As shown in FIG. 2C, the subcomponent flow Q 1 , which is preferably a diluting water flow, is passed from the inlet header 120 through the ducts23a 1 ,23a 2 , . . . , 23a n and further into respective mixer units 22a 1 ,22a 2 , . . . , 22a n . From the mixer units, in which the subcomponent flow Q 1 is mixed with the subcomponent flow Q 2 , the combined flow is directed into the duct 25a 1 of the mixer unit and then into the distributor pipe/compartment 28a 1 ,28a 2 . . . . From the distributor pipe/compartment 28a 1 ,28a 2 , the flow is passed through respective throttles D 1 ,D 2 , . . . into turbulence tube 19a 2 of the turbulence generator 19. The turbulence tube 19a 2 carries the pulp therein, in acorresponding vertical height position, into the space between the flaps 16a 1 ,16a 2 in the discharge duct 14.
FIG. 2D is a sectional view taken along the line IV--IV in FIG. 1. As shownin FIG. 2D, the flow Q 2 is passed to the mixer units 22a 1 ,22a 2 , . . . , 22a n from the inlet header 130. It is essential that the concentration of the subcomponent flow Q 2 differs from the concentration of the subcomponent flow Q 1 . Preferably, the subcomponent flow Q 1 consists of diluting water, and the subcomponentflow Q 2 consists of pulp. From the inlet header 130, the subcomponent flow Q 2 is passed into the pipes 24a 1 ,24a 2 . . . and into each particular mixer unit 22a 1 ,22a 2 . . . , in which the subcomponent flows Q 1 and Q 2 are mixed at a certain mixing ratio. The combined subflow Q 3 is passed through the respective ducts25a 1 ,25a 2 . . . into the respective compartments 28a 1 ,28a 2 of the distributor pipe and further through the throttles D 1 ,D 2 . . . into the turbulence generator 19 into eachparticular turbulence tube 19a 2 and from there, into the discharge duct 14.
FIG. 3 is an illustration of principle of a mixer unit 22 in accordance with the invention by whose means it is possible to supply a pulp flow having a desired consistency to a certain pulp suspension layer and to a certain position of width of the multi-layer headbox. By means of the mixer unit shown in FIG. 3, it is possible to regulate the grammage profile. In a corresponding manner, by means of the mixer unit, it is possible to regulate the fiber orientation profile by acting upon the pressure loss in the pulp flow passing through the mixer unit and, thus, upon the velocity of the flow and the flow quantity.
FIG. 3 is an illustration of the principle involved in the operation of themixer unit 22. The mixer unit 22 comprises a first inlet duct 23, through which the first subcomponent flow Q 1 , preferably a so-called 0-water flow, is introduced into a chamber F of the mixer unit. Further, the mixerunit 22 comprises a second duct 24, through which the second subcomponent flow Q 2 , which is preferably a subcomponent flow at the average concentration of the third pulp suspension component flow, is also introduced into the chamber F of the mixer unit 22. The flows pass, at theconsistency ratio distributed by a distributor part 26 placed in the chamber F, through a transverse duct 27 of the distributor part 26 and into an outlet duct 25. The combined subflow Q 3 (the sum of the subcomponent flows Q 1 +Q 2 ) is passed to a certain position alongthe width of the headbox of the paper machine. In accordance with the invention, each position of width of the paper machine comprises a separate duct 28a 1 ,28a 2 . . . , in front of which there is a respective mixer unit 22a 1 ,22a 2 ,22a 3 . . . , by whose meansit is possible to regulate the concentration of the pulp suspension component flow departing from the mixer units at that position of width. In addition, it is also possible to regulate the flow velocity of the pulpsuspension and, thus, the flow quantity or rate.
As shown in FIG. 3, the distributor part 26 can be displaced along a linearpath (arrow L 1 ) in the chamber F, and the distributor part 26 can alsobe rotated (arrow L 2 ) in the chamber F. Upon rotation of the distributor part 26, a mouth part 27a of the flow duct 27 extending acrossthe distributor part 26 can be brought into different positions in relationto the end openings 23a,24a of the inlet ducts 23 and 24. Thus, the subcomponent flows Q 1 ,Q 2 in the ducts 23 and 24 can be regulatedby increasing the throttle, i.e. the flow resistance, of the subcomponent flow Q 1 in the duct 23 and reducing the throttle, i.e. the flow resistance, of the subcomponent flow Q 2 in the duct 24, or vice versa. This regulation is achieved because the size of the mouth part varies upon rotation of the distributor part 26. By shifting the distributor part 26 along a linear path, the mixing ratio of the componentsubflow Q 3 is affected and when the distributor part 26 is rotated, the pressure loss in the combined component subflow Q 3 is affected.
FIG. 4A is an illustration of principle of a regulation in accordance with the invention. In the regulation position of FIG. 4A, the flow has access through the sectional flow areas U 1 and U 2 denoted by the shading into the duct 27 in the distributor part 26. The end opening of the duct 23 is denoted by 23a, and the end opening of the duct 24 is denoted by 24a. The sectional flow area of the end opening 23a is A 1 ,and it corresponds to the sectional flow area of the end opening 24a (provided ducts 23 and 24 have the same dimensions). The shapes of the openings 23a and 24a are similar to one another. The central axis of the opening 23a is denoted by X 1 , and the central axis of the opening 24ais denoted by X 2 . The connecting line of the axes X 1 and X 2 is denoted by Y. The orifice of the flow duct 27 in the regulation part 26is denoted by 27a in the figure. When the overall flow quantity or rate Q 3 is desired to be increased, the sectional flow area U 1 ,U 2 is increased through which the flow takes place into the duct 27 in the regulation part 26 and (in the way shown in the figure) thedistributor part 26 is raised or lowered perpendicularly to the line Y (in the direction N). In a corresponding manner, when only the mixing ratio ofthe subcomponent flows Q 1 ,Q 2 is desired to be changed, the orifice 27a is displaced in the direction N', which is perpendicular to the direction N. The flow openings 23a,24a are arranged in relation to oneanother that at least one of the central planes coincide and that at least one central planes perpendicular to the central planes are parallel to oneanother.
In FIGS. 4A, 4B and 4C, the regulation positions of the embodiment as shownin the embodiment of FIG. 3 is examined, wherein the distributor part includes a duct 27. It is noted though that the above examination also applies to the embodiment shown in FIG. 7, in which the distributor part 260 is a tumbler part, which does not include a separate transverse duct and by means of which tumbler part the end openings 23a,24a of the ducts 23,24 for the component flows are closed and opened.
When the distributor part 26 is shifted along a linear path in the manner shown in FIG. 4B, the sectional flow area U 1 of the subcomponent flowQ 1 coming from the duct 23 is increased, and the sectional flow area U 2 of the subcomponent flow Q 2 is reduced by a corresponding proportion. Thus, in the regulation, the mixing ratio is changed, but the sum of the flow quantities Q 3 =Q 1 +Q 2 remains invariable.
If it is desired to act upon the flow quantities of the flows Q 3 in the manner shown in FIG. 4C, the distributor part 26 is shifted to the side (arrow L 2 ) (e.g., by rotation), in which case, at the same time,the sectional flow areas U 1 and U 2 are reduced. When the sectional flow areas U 1 ,U 2 are increased, the mixing ratio must remain unchanged. If U 1 was, in the initial situation, larger than U 2 , then in the new position, U 1 is increased by a larger amountthan U 2 . In a corresponding manner, when the sectional flow areas U 1 and U 2 are reduced, and if U 1 is larger than U 2 , the reduction of U 1 must be greater than the reduction of U 2 . The valve mechanism in accordance with the invention achieves the maintaining of the mixing ratio invariable in the regulation of the flow quantity while varying the quantity of the total flow. Thus, in the regulation of the flow quantity, when the distributor part 26 is rotated, the pressure loss of the flow is affected, and thereby the velocity profile of the flow and further the fiber orientation profile are affected. The regulation does not affect the concentration of the subflow Q 3 , and thereby the concentration D 3 of the pulp suspension in the overall subflow Q 3 flowing out of the duct 25 is kept at its desired regulated value.
FIG. 5A is a sectional view of a first preferred embodiment of a mixer unitin accordance with the invention, which corresponds to the illustrations inFIGS. 3 and 4A, 4B and 4C. As described above, the mixer unit 22 comprises a first inlet duct 23 and a second inlet duct 24 as well as an exhaust or outlet duct 25. The mixer unit also comprises a chamber F in which the distributor part 26 is fitted to be displaceable along a linear path (arrow L 1 ) and in which it is fitted to be rotatable (arrow L 2 ).
When the distributor part 26 is displaced along a linear path perpendicularly to the inlet axes X 1 ,X 2 and X 3 of the ducts23,24,25 (arrow L 1 ), respectively, the position of the inlet opening 27a of the transverse duct 27 in the distributor part 26 in relation to the end opening 23a of the first inlet duct 23 and to the end opening 24a of the second inlet duct 24 is affected. Thus, when the distributor part 26 is raised or lowered (arrow L 1 ), the flow is increased through thefirst inlet duct 23 into the transverse duct 27 in the distributor part 26,and the flow through the second inlet duct 24 is reduced by a correspondingamount, and vice versa. Thus, the mixing ratio between the subcomponent flow Q 1 coming from the inlet duct 23 and the subcomponent flow Q 2 coming from the other inlet duct 24 is changed, but the overall subflow quantity Q 3 of the subcomponent flows Q 1 ,Q 2 throughthe outlet duct 25 (Q 3 =Q 1 +Q 2 ) is kept invariable.
Out of the first inlet duct 23, preferably 0-water is made to flow. Out of the inlet duct 23, it is also possible to pass a pulp suspension whose concentration is, on the whole, different from the average concentration of the pulp suspension in the headbox, while the pulp having an average concentration is made to flow preferably through the second inlet duct 24.
When the distributor part 26 is rotated (arrow L 2 ), at the same time the throttle of the subcomponent flow Q 1 coming out of the first inlet duct 23 and the throttle of the subcomponent flow Q 2 coming outof the second inlet duct 24 are affected so that the flow resistances of the flows out of the ducts 23 and 24 are increased or reduced simultaneously. Thus, by rotating the distributor part 26, the pressure loss of the combined flow Q 3 =Q 1 +Q 2 is affected. When the pressure loss is increased or reduced, the flow quantity of the subflow Q 3 through the outlet duct 25 is increased or reduced. In this manner, it is possible to affect the velocity profile of the flow and further the pulp fiber orientation profile at the desired position along the width of the paper machine in the desired way.
The structure of the first preferred embodiment of the mixer unit shown in FIG. 5A is shown in more detail in FIG. 5B, which is illustration in the direction K 1 indicated in FIG. 5A, FIG. 5C which is an illustration in the direction K 2 indicated in FIG. 5A, and FIG. 5D, which is an illustration in the direction K 3 in FIG. 5A, i.e. from above.
FIG. 5E is an axonometric illustration of a disassembled distributor part 26 of the mixer unit 22 in accordance with the invention.
FIG. 6A is a sectional view of a second embodiment of the mixer unit 22 in accordance with the invention. Also in this embodiment, the mixer unit 22 comprises a first inlet duct 23 and a second inlet duct 24 and an exhaust or outlet duct 25 through which the combined flow Q 3 =Q 1 +Q 2 is removed. A distributor part 260 is arranged in the mixer unit 22 and comprises a displacing spindle 260a, by whose means the distributorpart 260 can be shifted into different covering positions in relation to the end opening 23a of the first inlet duct 23 and in relation to the end opening 24a of the second inlet duct 24. Through the first inlet duct 23, preferably 0-water is introduced. It is also possible to make such a pulp suspension flow through the duct 23 whose concentration is, on the whole, different from the average concentration of the pulp suspension in the headbox. However, the pulp suspension having an average concentration is made to flow preferably through the second inlet duct 24. Thus, in the manner shown in FIG. 6A, when the spindle 260a is rotated (arrow L 3 ),the distributor part 260, which operates as a tumbler part, is shifted intodifferent covering positions in relation to the end openings 23a,24a. When the distributor part 260 is displaced, the end opening 23a of the inlet duct 23 is opened, and the end opening 24b of the inlet duct 24 is closedby the corresponding amount, and vice versa. As a result, in this embodiment, as in the embodiment shown in FIG. 5, the mixing ratio can be continuously regulated and, yet, the flow quantity of the combined subflowQ 3 remains invariable, i.e. the pressure loss remains at its invariable value.
The duct 24 is passed to, leads to, the desired position of width of the headbox of the paper machine. In the direction of width, the headbox of the paper machine comprises a number of ducts 25a 1 ,25a 2 . . . , which are opened preferably into separate distribution pipes 28a 1 ,28a 2 . . . , each of which passes directly into a turbulence tube 19a 1 ,19a 2 . . . of its own placed in the same position of width in the turbulence generator 19.
FIG. 6B is a sectional view taken along the line V--V in FIG. 6A. The spindle 260a is rotated by means of the lever 260b.
FIG. 7A shows an embodiment of the invention which is in some respects similar to the embodiment of FIGS. 6A and 6B. However, in the embodiment shown in FIG. 7A, the flow quantity of the departing flow can also be regulated so that the mixing ratio remains at a regulated invariable value. In the embodiment of FIG. 7A, the spindle 260a is displaced along alinear path as indicated by the arrow L 5 in which case the distributorpart 260 connected with the spindle is placed in different covering positions in relation to the end openings 23a,24a so that, at the same time, the end openings 23a,24a are closed or opened. The regulation of themixing ratio takes place so that the spindle 260 is rotated (arrow L 4 ), whereby the distributor part 260 is shifted into different covering positions in relation to the end openings 23a,24a, and so that, when the sectional flow area of one end opening is increased, the sectional flow area of the other opening is reduced by the corresponding amount, and vice versa.
FIG. 7B is a sectional view taken along the line VI--VI in FIG. 7A. In the manner indicated in FIG. 7B, by means of the arrow L 5 , the distributor part 260 can be shifted along a linear path, whereby, at the same time, the end openings of the ducts 23 and 24 are opened or closed, in which case the throttle of the outlet subflow Q 3 is reduced or increased while the mixing ratio of the subcomponent flows Q 1 and Q 2 remains at its invariable value.
The examples provided above are not meant to be exclusive. Many other variations of the present invention would be obvious to those skilled in the art, and are contemplated to be within the scope of the appended claims.
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A method and device for the regulation of a pulp suspension flow in a multi-layer headbox and a multi-layer headbox for a paper machine/board machine. For the formation of different layers in the web, at least two pulp suspensions having different pulp concepts flow through the multi-layer headbox. The flow of a pulp suspension that forms one of the layers in the web is regulated by regulating the component flows that constitute this flow and regulating the concentration of the component flows independently from one another. In this manner, i.e., by regulating only this the particular layer, the total flow of the pulp suspension leaving the headbox is regulated.
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BACKGROUND OF THE INVENTION
The present invention relates to a clamping collar for hermetically (i.e. perimetrically sealingly) connecting axially aligned ends of two tubular parts, in particular those designed to form the exhaust conduit of a vehicle exhaust pipe.
It will find an application in all those sectors of economic activity in which it is necessary to have recourse to a clamping collar in order to ensure the hermetic connection of two parts, in particular of circular cross-section and, more particularly, in the field of motor vehicle construction for the manufacture of exhaust pipes.
Such clamping collars further have the function of exerting tangential stress upon the member about which they are placed in order, in particular, to cause a reduction of their radial dimensions and thus to ensure clamping.
There are currently various types of clamping collar in existence, the shape and constitution of which are, furthermore, adapted to their intended use.
In particular, in certain specific applications, such clamping collars further have to possess properties enabling them to ensure the hermetic connection of the parts. Such a characteristic is required, in particular, in the case of their application to the hermetic connection of conduits constituting the exhaust system of a vehicle.
It should also be noted that, in such applications and, in particular, in the exhaust systems of engines and most especially those of vehicles, such collars also have to withstand high temperatures, as well as considerable temperature variations. Furthermore, they also have to withstand substantial mechanical forces and stresses resulting, in particular, from the vibrations and dynamic stresses arising from the operation of the engine.
To enable these different forces and stresses to be withstood, the connection between the two successive portions of an exhaust system can be provided by a clamping collar having a substantially V-shaped cross-section and into which the ends to the two portions of the exhaust system that are in contact are intended to fit, these two ends further having substantially conical matching bearing surfaces projecting perpendicularly to their cylindrical outer surfaces.
Such clamping collars are constituted, for example, by two rigid semi-cylindrical parts each terminating at their end in a fixing ring and being held together by means of screws passing through the facing lugs of the collar.
There is thus obtained a close, strong contact between the collar and the two portions of the exhaust system. However, in practice, such collars do not give satisfaction since they are of complex design, and they are not always easy to put into place or remove, which, it will be appreciated, leads to added costs when assembling or disassembling a vehicle exhaust system.
Furthermore, such collars necessitate the fitting of at least two bolts so as to assemble and clamp the two rings of the collar. The clamping forces are thus poorly exploited and, especially, poorly distributed, since they tend to draw together the two semi-circular members constituting the relatively rigid collar without exerting uniform traction distributed over its periphery, which is detrimental to the sealing characteristics of the clamping of the two parts of the exhaust system.
To remedy these drawbacks there has been devised a collar that is constituted by an open ring, the cross-section of which is in the shape of an inverted V and the ends of which comprise bearing lugs, for clamping means, which lugs extend radially into the vicinity of the internal periphery of the ring.
For this purpose there has been devised a ring that is deformable for tightly pressing against one another the conically shaped matching bearing surfaces of the tubes, and which has means for clamping and holding the ring in closed position, constituted in a manner known per se by a nut and screw assembly. On its periphery, the head of the screw has a V-shaped notch corresponding to the cross-section of the ring so as to come to bear on a first lug at least in the area of connection thereof to the ring. There is also provided, between the nut and the second lug, a stop analogous to that of the head of the screw, slidingly mounted on the screw and designed to come to bear on the said second lug at least in the area in which it is connected to the ring.
In practice, such clamping collars are also difficult to remove, which gives rise to numerous drawbacks, particularly when it is necessary to replace a vehicle exhaust system.
Now, vehicle exhaust members are generally subject to rusting phenomena, all the more swiftly in that they are heated to high temperatures. Moreover, they are placed beneath the vehicle and, as a result, through their arrangement and their positioning, they are also liable to receive all sorts of projections, so that their different component parts tend to jam, thus making their disassembly a delicate matter.
Furthermore, with such currently used collars, the replacement of one of the parts in a vehicle exhaust system necessitates the replacement of the clamping collar which, in addition to the cost increase arising from the difficulty of dismounting it, generates an increase in the price of such operations.
SUMMARY OF THE INVENTION
The object of the present invention is to remedy the drawbacks of presently known collars by providing a clamping collar for hermetically connecting two parts intended, in particular, to form the exhaust conduit of a vehicle, which is easy to install and/or remove, while, at the same time, ensuring hermetic connection of the different members in the exhaust system.
Furthermore, with a collar according to the invention, the mechanical fixing and hermetic properties are obtained together with ease of assembly and disassembly. These hermetic properties also make for a reduction of undesirable noise, which broadens its potential applications.
Another object of the invention is that it should be possible for the clamping collar to be mass produced without necessitating the implementation of complex means, thus reducing its cost and its cost price.
A further object of the invention is that it should be possible to re-use the clamping collar if necessary after removal and, in particular, after the replacement of those parts of the exhaust system that have to be changed.
Another object of the present invention is to provide a clamping collar that is of a robust design so that it can withstand the various phenomena of rusting and/or mechanical stress resulting from its use for the hermetic connection of parts such as, in particular, those of the exhaust conduits of a vehicle exhaust pipe.
Further objects and advantages of the present invention will emerge in the course of the following description, which is given only by way of illustration and is not intended to limit same.
For this purpose, the invention provides a clamping collar for connecting two parts having a circular cross-section, designed, in particular, to form a vehicle exhaust conduit, comprising:
a strip bent into an open loop whereof the ends, spaced from one another, have substantially radially extending bearing lugs;
clamping means pressing in the area of the ends to exert a circumferential stress clamping the collar onto said parts.
It is characterized by the fact that the clamping means comprise means for separating the two ends when they are unclamped with a view to facilitating its opening and removal.
BRIEF DESCRIPTION OF THE DRAWINGS
The present invention will be more readily understood upon reading the following description accompanied by the annexed drawings, wherein:
FIG. 1 is a front view schematically illustrating a collar according to the invention;
FIG. 2 is a schematic view in the direction of arrow F 1 of FIG. 1 illustrating a bearing lug of the clamping collar which cooperates with the head of the tightening screw;
FIG. 3 is a schematic view in the direction of arrow F 2 of FIG. 1 schematically representing a bearing lug of the collar according to the invention which cooperates with the head of the tightening screw;
FIG. 4 is a schematic view illustrating a tightening screw according to the invention;
FIG. 5 is a schematic exploded view illustrating the component parts of the tightening screw according to the invention;
FIG. 6 is a view in partial cross-section schematically illustrating a bearing lug which cooperates with the tightening screw in non-locked position;
FIG. 7 is a view similar to that of FIG. 6 schematically illustrating the tightening screw in locked position;
FIG. 8 is a partially cross-sectional view schematically illustrating a bearing lug which cooperates with a tightening screw;
FIG. 9 is a front view schematically illustrating an alternative form of embodiment of a collar according to the invention;
FIG. 10 is a schematic view in the direction of arrow F 3 of FIG. 9 schematically representing a bearing lug of the collar according to the alternative form of embodiment which cooperates with the head of the tightening screw; and
FIG. 11 is a schematic view in the direction of arrow F 4 in FIG. 9 schematically representing a bearing lug of the collar according to the alternative form of embodiment, which cooperates with the head of the tightening screw.
DETAILED DESCRIPTION
The present invention relates to a clamping collar 1 for hermetically connecting two parts of circular cross-section, designed, in particular, to constitute the exhaust system of a vehicle exhaust pipe. It will find an application, in particular, in the automotive industry for the purpose of connecting and clamping the various exhaust members, but it is also perfectly feasible to have recourse to this clamping collar in any other sectors of economic activity in which two parts, in particular having a circular cross-section, have to be connected hermetically.
Furthermore, such parts to be connected have, in the type of application described, facing ends to be assembled which have matching bearing surfaces of substantially conical shape projecting substantially perpendicularly in relation to their cylindrical outer surfaces.
To assemble such parts the collar 1 according to the invention takes the form, herein, of an open ring 2 made of a metallic material, the cross-section of which is V-shaped. Such a collar is generally produced using conventional manufacturing techniques and, in particular, by the forming of a flat sheet of metal. The thickness of the metal sheet will depend, of course, upon the applications, and it is further determined to afford appropriate resistance to the torsional stresses that will be applied to the collar during its clamping.
For the purpose of producing vehicle exhaust systems, use is made of two tubes manufactured from a metallic material, possessing adequate strength, but of small thickness and the ends for assembly of which have substantially conical matching bearing surfaces projecting substantially perpendicularly in relation to their cylindrical outer surfaces. That is the reason for which it is advantageous for the internal angle of the inverted V-section of the collar to match the angle formed by the conical sides of the facing conical surfaces of the parts to be assembled, so that it is possible to obtain, with such an arrangement, a sufficiently hermetic connection between these two tubes.
Each of the free ends, 3 and 4, of the ring 2 comprises a substantially radially extending bearing lug 5, 6.
According to the invention, this clamping collar 1 comprises clamping means applied in the area of the ends 3 and 4 to exert a circumferential stress clamping the collar, constituted by a screw-nut assembly 7 which comprises means 8 for separating the ends 3 and 4 and for enabling them to be slackened in order to facilitate the opening and removal of the collar 1.
These means 8 for slackening the collar are formed, on one hand, by an oblong orifice 9, provided in at least one of the bearing lugs 5, inside which is placed a screw 10 and, on the other hand, by a stop 11, provided substantially at one of the ends of the threaded shank 12 of screw 10, with a shape matching the oblong orifice 9, and which delimits, with head 13 of screw 10, an annular groove 14, as illustrated in FIG. 4.
It will be noted that stop 11 delimits two protuberances 15 and 16 which ensure that the clamping means are locked in translation when it is necessary to arrange the ring 2 in the area of connection of the two members of the exhaust system, and thus ensure hermetic connection between them.
It should also be emphasized that bearing lugs 5 and 6 have, on either side of a vertical median plane, a reinforcing side piece 17 which can be produced by appropriately upsetting the metal sheet during manufacture of the ring 2.
These reinforcing side pieces 17 delimit in the lug 5 a housing 18 and inside the lug 6 a housing 19.
Inside the housing 19 is placed a bearing ring 20 which is substantially square in shape and in which is provided, substantially in its central portion, an orifice 21 designed to take up a position facing an oblong orifice 22 provided in bearing lug 6.
This bearing ring 20 cooperates with a nut 23, such as the one that is more particularly illustrated in FIG. 5, and which comprises a cylindrical body 24 with an outside diameter that is substantially smaller than the inside diameter of orifice 21 and of oblong orifice 22, so as to be able to pass through them. This cylindrical body 24 is hollow 1 and it has an internal threaded portion 25 designed to cooperate with the thread of threaded shank 12.
The other end of body 24 of nut 23 comprises an annular ring 26 and ends in a head 27 which is, here, a hexagonal head.
To ensure that the nut 23 is maintained in its mounted position, as more particularly illustrated in FIG. 2, the end 24a of cylindrical body 24 is bent back forming an annular skirt 28 which prevents any possibility of its displacement to cause it to leave the oblong orifice 22.
This annular skirt 28 is produced, in particular, by swaging or upsetting the end 24a of the cylindrical body 24 of nut 23 after the latter has been placed in a position such that it passes, on one hand, through orifice 21 and, on the other hand, through the oblong orifice 22 provided in lug 6, this operation being carried out during the manufacture of the collar in accordance with the invention prior to its being put into place, so that this nut 23 is already held in a working position, illustrated in FIG. 8, such as the one that will now be described.
To enable the collar 1 according to the invention to be put into place, it suffices firstly to position the body of ring 2 in the conical area of connection of the two members of the exhaust system.
By exerting a tightening action, for example through the use of a spanner (i.e. a wrench) on the head of the nut 27, one acts on the clamping means 7 and tightens the two ends, 3 and 4, of ring 2 so as to ensure hermetic connection of the two pieces of the exhaust system.
Furthermore, as a result of the tightening action, the head 13 which is, in particular, square, of screw 10 becomes rotationally locked inside housing 19 provided in bearing lug 6, and translationally locked via protuberances 15 and 16 and by the annular groove 14 that is located in a position such as illustrated in FIG. 7, so that efficient and appropriate clamping of the collar is obtained, ensuring hermetic, efficient connection of the two pieces.
It should be noted that, owing to the immobilization of screw 10 and of the tightening action exerted upon nut 27, regular homogenous distribution of the mechanical clamping forces and stresses is obtained, thus making it possible to ensure that the two pieces of the exhaust system are held efficiently and appropriately, while at the same time preventing localized deformation thereof prejudicial to their correct use.
It should also be noted that, owing to the special shape of oblong orifices 9, 22, provided respectively in bearing lugs 5 and 6, it is possible to ensure easy, swift installation, as well as good positioning of the different clamping members and, in particular, of screw 10, which further makes it possible to make up for the play that sometimes exists between the two pieces to be assembled.
According to the invention, collar 1 is also easy to dismount, which widens its potential uses and, in particular, permits its possible re-use when, for example, one of the pieces that has been assembled has to be replaced.
Furthermore, such dismounting of the collar 1 is simple, as it suffices to exert a slackening action, through the use of a spanner on head 27 of nut 23. This operation is facilitated, moreover, by the fact that the screw 10 is in a position, represented in FIG. 7, translationally locked via protuberances 15 and 16 and by groove 14, and rotationally locked via head 13, which is locked in housing 19 in bearing lug 5.
Thus, by applying a slackening action to the head of nut 27, using a spanner, one releases the thread 12 of screw 10 which is inserted inside the tapped portion 25 of nut 23 and through this action the two ends 3 and 4 of ring 2 are separated in order to be able to remove the collar 1 and release the two pieces that had been connected together in their conical portions.
With more particular reference to FIGS. 9 to 11, an alternative embodiment of the collar according to the invention is represented whereof the elements common to those of the form of embodiment described previously bear the same references.
More precisely, here, means 8 are constituted by at least one curved portion 30 of lug 5 which delimits, with the body of ring 2, a housing 34 designed to receive the head 36 of a screw and by a curved portion 31 of lug 6 which also delimits, with the body of ring 2, a housing 35 designed to receive a nut 37.
Each lug 5, 6 comprises an orifice 38, 39, the inside diameter of which is slightly greater than the outside diameter of screw 10, and each curved portion 30, 31 also comprises an orifice 40, 41 having a diameter such as to facilitate the passage and putting into place of screw 10 and which is, in particular, oblong to facilitate the positioning of the tightening tool.
As regards curved portions 30, 31, these are obtained by machining and forming a flat metal sheet, as more especially illustrated in dotted lines in FIG. 9, wherein orifices 40 and 41 have been previously pierced. This operation is carried out after putting screw 10 into place through holes 38, 39 provided in each lug 5, 6 and the lock nut 37. To prevent the body of the screw from passing through orifice 38 provided in lug 5 the head 36 of the screw has a diameter which is far greater than that of the orifice.
To ensure that nut 37 is held and rendered integral with curved portion 31, the curved portion 31 of lug 6 is swaged, during manufacture of the collar, so that nut 37 is crimped in the strip of sheet metal and can no longer move translationally or rotationally. Of course, is it also conceivable to ensure that this nut 37 is immobilized using weld spots, but this technique would necessitate the implementation of far more complex means, which would increase the cost of manufacturing the collars. This method of immobilization further makes it possible to hold and put the screw 10 into place in an appropriate position.
It should also be noted that curved portions 30 and 31 make it possible to enhance the mechanical rigidity of this portion of the collar, which increases its potential applications, particularly under difficult conditions.
The diameter of orifice 40 of curved portion 30 is adapted to permit the passage of a tightening tool suitable for cooperating with the screw head 36 such as, for example, a head commonly known as a "torx" or "6 point socket".
Through the use of this tool, when a slackening action is applied to screw 10 by unscrewing the screw head 36, the tool holds the curved portion 30 in a given position and the screw head 36 comes into abutment with the curved portion inside housing 34, which makes it possible to slacken the collar more easily.
To re-tighten it suffices, using the tool, to apply a screwing action to the screw head 36 so as to cause the parts of the strip bent into an open loop, and in particular of the two spaced apart ends 3 and 4, to come together.
The present invention is not limited to this form of embodiment as described hereabove but it extends to all alternative forms of embodiment.
Other implementations of the present invention, within the grasp of a person of ordinary skill the art, could have been contemplated without thereby departing from the scope thereof.
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A clamping collar for sealing by perimetrically connecting the axially aligned ends of two parts which are circular in external transverse cross-sectional shape. The collar includes a strip formed into an open loop, V-shaped in longitudinal section, having two circumferentially opposite ends, and a tightener for extending force on the ends for circumferentially tightening the collar on the ends of the two parts. The tightener includes a separator for separating the two ends when the collar is loosened, for facilitating the opening and removal of the collar from the parts.
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BACKGROUND OF THE INVENTION
1. Cross-Reference to Related Application
The present application is a continuation-in-part of my application Ser. No. 866,151, filed on May 22, 1986, now U.S. Pat. No. 4,702,738.
2. Field of the Invention
The present invention is in the field of hypodermic syringes and needles. More particularly, the present invention is directed to a disposable hypodermic syringe and needle combination which has a retractable sheath to prevent accidents and abuse of the syringe and needle combination.
3. Brief Description of the Prior Art
Disposable hypodermic syringes and needles have been known in the art for a long time.
Hypodermic syringes and needles are often used for administering medication to patients suffering from infectious diseases. Therefore, it has been considered of great importance in the art to avoid accidents where doctors, nurses, or other persons are wounded by used hypodermic needles. Presently, the safe disposal of used syringes and needles is considered a serious problem in the art, particularly in light of the recent spread of acquired immunodeficiency syndrome (AIDS), and of the widespread abuse of syringes and needles by addicts for administering illicit drugs.
In order to solve or ameliorate the foregoing problems, the prior art has provided rigid, puncture resistant disposable plastic containers into which doctors or nurses are expected to deposit disposable hypodermic syringes and needles immediately after their use. The containers, filled with the discarded syringes and needles, are then sealed and eventually disposed of. The disposal is ideally conducted in a manner which does not permit access to unauthorized persons desiring to obtain the syringes and needles for illegal or like abusive purposes. In spite of the foregoing and other precautions, accidents still occur with used hypodermic needles, sometimes with tragic consequences. Moreover, discarded syringes and needles are still often misappropriated for illegal, or drug abuse, purposes.
The foregoing problems remain especially acute in connection with syringes and needles used by paramedics, because paramedics often are unable to carry the specialized plastic containers required for safe disposal. Moreover, personnel working in housekeeping duties in hospitals presently are still often exposed to improperly discarded hypodermic syringes and needles. The present invention is designed to solve or substantially ameliorate the above-described problems.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a disposable hypodermic syringe and needle combination wherein the needle is protected before and after use, to prevent accidents involving the used needle.
It is another object of the present invention to provide a disposable hypodermic syringe and needle combination wherein the needle is protected before use, and wherein the needle is permanently and irreversibly concealed after use so as to prevent abuse by users of illicit drugs.
The foregoing and other objects and advantages are attained by a hypodermic syringe and needle combination having a sheath mounted to the barrel in a first position wherein the sheath extends and conceals the needle. The sheath is movable on the barrel to occupy a second position wherein the needle is at least partially exposed. The needle and syringe combination is normally used to fill the syringe with medication and inject it into the patient in the second position of the sheath. The sheath is also movable to a third position on the barrel wherein the sheath again conceals the needle. The sheath is preferably irreversibly locked into the third position for disposal so that the combination cannot be retrieved and used for illegal or unauthorized purposes.
In accordance with another feature of the invention, the sheath is made from a plastic material which softens and loses its structural integrity at temperatures below the autoclaving temperatures required for sterilizing items in medical practice. Consequently, the needle and syringe combination is destroyed upon attempted sterilization in an autoclave, because the sheath "melts" and renders the combination unusable. This feature ensures that the combination is used only once.
The features of the present invention can be best understood together with further objects and advantages by reference to the following description, taken in connection with the accompanying drawings, wherein like numerals indicate like parts.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a first preferred embodiment of the hypodermic syringe and needle combination of the present invention, the view showing a protective sheath extended to cover and conceal the needle;
FIG. 2 is another perspective view of the first preferred embodiment, the view showing a protective sheath retracted, thereby exposing the needle;
FIG. 3 is still another perspective view of the first preferred embodiment, the view showing the protective sheath again extended and locked into position after the combination has been used;
FIG. 4 is a cross-sectional view taken on lines 4,4 of FIG. 1;
FIG. 5 is a cross-sectional view taken on lines 5,5 of FIG. 2;
FIG. 6 is a cross-sectional view taken on lines 6,6 of FIG. 3;
FIG. 7 is a partially exploded side view of the first preferred embodiment;
FIG. 8 is a side view of the first preferred embodiment with a portion of the protective sheath broken away, the view showing the protective sheath in its extended position covering the needle;
FIG. 9 is a partial side view of the first preferred embodiment, with a portion of the protective sheath broken away, the view showing the protective sheath in its retracted position wherein the needle is exposed;
FIG. 10 is another partial side view of the first preferred embodimett, with a portion of the protective sheath broken away, the view showing the protective sheath in its extended locked position covering the needle;
FIG. 11 is a cross-sectional view, the cross-section being taken on lines 11,11 of FIG. 8;
FIG. 12 is a perspective view of a second preferred embodiment of the hypodermic syringe and needle combination of the present invention, the view showing a protective sheath extended to cover the needle;
FIG. 13 is a side view of the second preferred embodiment, partly in cross-section, the side view showing the protective sheath extended to cover the needle;
FIG. 14 is a partial side view of the second preferred embodiment, partly in cross-section, the view showing the protective sheath retracted to expose the needle;
FIG. 15 is a cross-sectional view of the second preferred embodiment, the cross-section being taken on lines 15,15 of FIG. 13;
FIG. 16 is a partial cross-sectional view of the second preferred embodiment, the cross-section being taken on lines 16,16 of FIG. 15;
FIG. 17 is a partial cross-sectional view of a third preferred embodiment of the hypodermic syringe and needle combination of the present invention, the view corresponding to an extended position of a protective sheath to cover the needle;
FIG. 18 is another partial cross-sectional view of the third preferred embodiment, the view corresponding to an extended and irreversibly locked position of the protective sheath to cover the needle;
FIG. 19 is a side view, partly in cross-section, of a fourth preferred embodiment of the hypodermic syringe and needle combination of the present invention, the view showing a protective sheath extended to cover the needle;
FIG. 20 is another side view, partly in cross-section, of the fourth preferred embodiment, the view showing a protective sheath retracted to cover the needle;
FIG. 21 is a cross-sectional view taken on lines 21,21 of FIG. 19;
FIG. 22 is a cross-sectional view taken on lines 22,22 of FIG. 21, the view corresponding to an extended position of the protective sheath to cover the needle;
FIG. 23 is another cross-sectional view of the fourth preferred embodiment, the view corresponding to a locked position of the protective sheath to cover the needle, and
FIG. 24 is a cross-sectional view taken on lines 24,24 of FIG. 23.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The following specification taken in conjunction with the drawings sets forth the preferred embodiments of the present invention. The embodiments of the invention disclosed herein are the best modes contemplated by the inventor for carrying out her invention in a commercial environment, although it should be understood that several modifications can be accomplished within the scope of the present invention.
Referring now to FIGS. 1 through 11 of the appended drawings, a first preferred embodiment 30 of the hypodermic syringe and needle combination of the present invention is disclosed. The first preferred embodiment 30 includes a syringe barrel 32 and a plunger 34 mounted into the barrel 32 at its first end 36. A hypodermic needle 38 is mounted in a conventional manner to the second end 40 of the barrel 32.
As an important novel feature, a sheath 42 is mounted to the barrel 32 at the same end 40 of the barrel 32 where the needle 38 is mounted. As is best shown on the perspective view of FIG. 1, in its normal or first position, the sheath 42 is disposed to conceal and cover the needle 38. The combination of the first preferred embodiment 30 is assembled during manufacture, and is kept, during shipping, storage, and preliminary preparation for administration of medication (not shown) to a patient (not shown), with the sheath 42 in its extended first position. To insure sterility, the sheath 42 is preferably sealed to the barrel with an airtight flexible plastic wrap (not shown) The flexible wrap (not shown) also serves as a tamper indicator.
The end 44 of the sheath 42, which is remote from the barrel 32, is tapered in the first preferred embodiment 30, and bears a friction fitted plastic cap or cover 46. The cap or cover 46 is shown on FIGS. 1 and 8.
As is apparent from FIGS. 1 through 11, the sheath 42 can be moved on the barrel 32 to expose the needle 38 when it is desired to fill the barrel 32 with medication (not shown) and administer the medication (not shown) to a patient (not shown). More particularly, the sheath 42 is locked in its first position to the barrel 32, but can be dislodged from the first position to be moved to a second position to expose the needle 38. The second position is shown on FIG. 2. Still a third position of the sheath 42 relative to the barrel 32 and needle 38 is shown on FIG. 3. In the third position, into which the sheath 42 is placed for disposal of the hypodermic syringe and needle combination 30, the sheath 42 is substantially irreversibly locked to cover and conceal the needle 38. Consequently, in its "disposal state", the hypodermic syringe and needle combination 30 cannot be accidentally reused, and the needle 38 is prevented from accidentally wounding someone, thereby potentially spreading dangerous infectious disease. As an added safety feature, after the sheath 42 is locked into the third position shown on FIG. 3, but before final discarding, the cap or cover 46 is preferably refitted to the sheath 42.
The above-described functions of the preferred embodiment 30 are accomplished by the structure illustrated in FIGS. 1-11. More particularly, the surface of the barrel 32 includes a channel or groove having two interconnected elongated parallel portions, which respectively bear the reference numerals 48 and 50 on the drawing Figures. The interior surface of the sheath 42 includes a protrusion or boss 52 which fits into and is guided in the channels 48 and 50. The channels or grooves 48 and 50 are approximately 0.008" to 0.012" deep.
The partial cross-sectional view of FIG. 4 shows the boss 52 placed into the channel 48 in the first position of the sheath 42 (in which the combination 30 is normally kept prior to use). In order to reversibly lock the sheath 42 in this position the guide channel 48 has a depression or cavity 54 in a location corresponding to the location of the boss 52 in the first position of the sheath 42. The cavity 54 includes a camming surface 56 comprising a slope or a radius, which permits the substantially square-shaped boss 52 to ride out of the cavity 54 in one direction only. FIG. 4 also shows a slope or camming surface 58 at the end 40 of the barrel 32, which permits the initial mounting of the sheath 42 on the barrel 32 without serious interference by the boss 52. FIG. 7 shows well the interconnecting guide channels 48 and 50, and also shows the sheath 42 before it is initially mounted to the barrel 32. The configuration of the cavity 54 shown on FIG. 4 renders it substantially impossible to remove the sheath 42 from the barrel 32 without breaking or damaging the boss 52 and thereby the entire combination 30. In addition to FIG. 4, FIGS. 8 and 11 also show the sheath 42 mounted to the barrel 32 in the first position wherein the boss 52 engages the cavity 54 in the guide channel 48.
FIGS. 2, 5, and 9 indicate the second position of the sheath 42 relative to the barrel 32. In this position, the boss 52 of the sheath 42 engages a second depression or cavity 60, which is located almost at the upper end of the guide channel 48. The shape or configuration of the second cavity 60 is similar to that of the first cavity 54, so that the boss 52 can ride out of the second cavity 60 in the upwardly direction only.
FIGS. 6 and 10 show the boss 52 of the sheath 42 engaging, in the third position of the sheath 42, a third depression or cavity 62 located substantially at the lower end of the guide channel 50. The third cavity 62 has no slope or camming surface; rather it has straight walls 64 designed to capture the boss 52, and thereby irreversibly lock the sheath 42 in the position concealing the needle 38. It is apparent from an inspection of FIG. 6 that the sheath 42 can be moved out of the third position only by breaking or substantially damaging the boss 52.
All components of the above-described combination 30, with the exception of the metal body of the needle 38, can be manufactured by injection molding from plastic materials of the type ordinarily used for the manufacture of hypodermic syringes. Medical grade polypropylene, for example, is suitable material for the manufacture of the syringe.
The sheath 42, however, can be made of a lower non-medical grade of plastic because it does not come into contact with medication. In fact, as an additional novel feature of the present invention, the sheath 42 is made of a plastic material which melts at substantially lower temperature than the medical grade plastic of the syringe barrel 32 and plunger 34, and which does not withstand the temperatures required for heat sterilization of syringes.
More particularly, in accordance with this feature, the material of the sheath 42 has a "deflection temperature" below the "deflection temperature" of the material of the syringe barrel 32 and plunger 34, and below the autoclaving temperatures normally required in medical practice to sterilize hypodermic syringes. Deflection temperature of a plastic material in this regard is understood to mean the temperature at which the material loses virtually all of its strength at very low stress. Thus, at temperatures slightly higher than the deflection temperature, the plastic material deforms, and "melts." Thus, exposing plastic articles to temperatures above their deflection temperature results in serious deformation (melting) of the articles.
The materials from which the sheath 42 is made in accordance with this feature preferably is also reasonably transparent. Acrylic styrene copolymer having a deflection temperature of 230° F. is eminently suitable for this purpose. Other suitable plastic materials include styrene-butadiene (deflect. temp. 158° F.), acrylonitril butadiene styrene (ABS) (deflect. temp. 170° F.), and an ionomer known under the trademark SURLYN of Dupont Corporation (deflect. temp. 129° F.) In this connection, acrylic styrene copolymer, styrene-butadiene and acrylonitril butadiene styrene are preferred
In light of the foregoing, if one were to attempt to heat sterilize the hypodermic syringe and needle combination of the present invention for reuse, the sheath 42 would melt and render the combination 30, particularly the needle 38, unusable. The just-described feature clearly reduces even further the potential for abuse of the hypodermic syringe and needle combination of the present invention.
Although the manner of using the first preferred embodiment 30 of the novel hypodermic syringe and needle combination of the present invention is apparent from the foregoing description and drawing figures, for the sake of further clarity and full disclosure, the steps are summarized as follows.
Just before use, the tamper evident wrapping seal (not shown) is removed by a doctor (not shown), nurse (not shown), or patient (not shown) from the hypodermic syringe and needle combination 30 of the invention. Thereafter, the cap 46 is removed from the end 44 of the sheath 42, and the sheath 42 is moved upward on the barrel 32, first by dislodging the boss 52 from the first cavity 54 and thereafter by sliding the boss 52 in the guide channel 48. Just before the boss 52 reaches the end of the guide channel 48, it snaps into the cavity 60, indicating that the sheath 42 has reached its second position relative to the barrel 32 and needle 38. The hypodermic syringe and needle combination 30 is used in this configuration to fill the barrel 32 with a drug or medication (not shown) and to administer the medication (not shown) into the patient (not shown). After administration of the medication, the sheath is moved slightly upward, turned, and thereafter moved downward relative to the barrel 32 by riding the boss 52 in the guide channel 50, until the boss 52 is captured in the third cavity 62. This locks the sheath 42 in its final position adapted for safe disposal of the combination 30. Optionally, just before the combination 30 is discarded and as an added safety feature, the cap 46 may be placed back on the end 44 of the sheath 42.
Apparent advantages of the above-described embodiment 30 include the excellent protection it affords against accidentally wounding the hands of doctors, nurses, or other personnel handling the syringe and needle combination 30, before, and especially after administration of a drug (not shown) to a patient (not shown), and the built-in safeguard against abuse or misuse of the syringe and needle combination.
Referring now to FIGS. 12 through 16, a second preferred embodiment 66 of the invention is shown. The second preferred embodiment 66 is similar in many respects to the above-described first preferred embodiment 30, and is therefore described here in less detail. Thus, the second preferred embodiment 66 of the syringe and needle combination of the invention also includes a sheath 42 which is mounted to the syringe barrel 32 for relative motion thereon.
The sheath 42 of the second preferred embodiment 66 includes, on its upper portion, a plurality of circumferentially and substantially evenly spaced fingers 68. As is best shown on FIG. 12, the fingers 68 are defined by the axially disposed slots 70 located in the upper portion of the sheath 42. Each finger 68 includes an inwardly directed boss or protrusion 52. The barrel 32 of the second preferred embodiment 66 includes two circumferential slots or grooves which bear the reference numerals 72 and 74, respectively.
In the second embodiment 66, the sheath 42 has two principal positions relative to the barrel 32 and needle 38. In the first position, shown on FIG. 13, the bosses 52 of the fingers 68 engage the lower circumferential groove 72, and the needle 38 is protected by the sheath 42. In the second position of the sheath 42, the bosses 52 of the fingers 68 engage the upper circumferential groove 74, and the needle 38 is exposed. After the hypodermic syringe and needle combination of the second preferred embodiment 66 has been used for administering medication, the sheath 42 is again placed into the first position wherein it covers the needle 38.
FIGS. 17 and 18 disclose a third preferred embodiment 76 which is similar in construction to the second embodiment 66, but, after the combination has been used for its intended purpose, permits permanent locking of the sheath 42 in the position where the needle 38 is covered. This is accomplished by providing two circumferential grooves 72 and 78 on the lower portion of the barrel 32. Before use, the camming bosses 52 of the fingers 68 rest in the circumferential groove 72 from which they are removed when the sheath 42 is moved upwardly on the barrel 32 to expose the needle 38. Before the third preferred embodiment 76 is used, additional square bosses 80 of the fingers 68 rest on the barrel 32, as is shown on FIG. 17. After use, the sheath 42 is locked into its position to cover the needle 38 by pushing the sheath 42 on the barrel 32 slightly below its original first position, whereby the square bosses 80 engage and lock into the groove 72, and the camming bosses 52 are simply accommodated in the circumferential groove 78.
FIGS. 19 through 23 disclose yet a fourth preferred embodiment 82 of the hypodermic syringe and needle combination of the present invention. The fourth embodiment 82 is similar in many respects to the first preferred embodiment 30 in that an inwardly directed boss 52 of the sheath 42 is guided in a guide channel 84 to accomplish the hereinafter-described functions. More particularly, in the first position of the sheath 42 it covers and protects the needle 38. In this position, the boss 52 is disposed in a side arm 86 of the guide channel 84. In order to prepare the syringe and needle combination 82 for use, the cap 46 is removed and the sheath 42 is slightly turned relative to the barrel 32 until the boss 52 is located in the main guide channel 84. The sheath 42 is then moved upward on the barrel 32 to expose the needle 38. After administration of a drug (not shown) by the combination 82, the sheath 42 is moved downwardly on the barrel 32, and is thereafter turned so as to guide the boss 52 into the second side arm 88 of the guide channel 84. After a slight upward pull, the boss 52 engages and locks into the cavity 90, thereby locking the sheath 42 into its final position for disposal. In this position the needle 38 is covered by the sheath 42, but for added safety the cap 46 is also replaced on the sheath 42.
What has been described above is a novel hypodermic syringe and needle combination having a movably mounted protective sheath to cover the needle before and after the use of the syringe and needle for administering drugs to patients, or in the course of veterinary medicine, drugs to animals. The novel combination of the present invention offers the advantages of safety, substantially eliminates the dangers of accidental wounding and infection of persons by used needles, and significantly reduces the danger for abuse or misuse of disposable syringes and needles.
Inasmuch as many modifications of the present invention may become readily apparent to those skilled in the art in light of the foregoing disclosure, the scope of the present invention should be interpreted solely from the following claims.
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A disposable combination of a hypodermic syringe and needle has a sheath movably mounted on the syringe barrel to normally occupy a first position wherein the sheath extends to cover and protect the needle. In a second position of the sheath, relative to the barrel and needle, the needle is at least partially exposed. In a third position of the sheath, which is used for disposal of the syringe and needle combination, the needle is again covered by the sheath and preferably the sheath is irreversibly locked whereby abuse or misuse of the syringe and needle combination is substantially prevented. The sheath is made from a plastic material, such as styrene butadiene or acrylic styrene copolymer, which has a deflection temperature below the temperature required for heat sterilizing syringes. Consequently, upon attempted sterilization by heat, the sheath melts, thereby further rendering the combination usable only once.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates generally to prosthetic apparatus and methods, and more particularly to a computerized electronic hand prosthesis apparatus and method utilizing configurable input, feedback, control, and operating systems to transmit feedback signals representing the gripping force back to the wearer in the form of vibratory stimuli which changes in vibratory pattern and amplitude at selective grip forces and allow precise positioning and gripping force control for a specific wearer.
2. Brief Description of the Prior Art
Although the mechanical hand is more acceptable than other prosthetic terminal devices, the problems associated with using a conventional mechanical hand prosthesis limits its usefulness and ultimately affects the wearer's acceptance of the prosthesis.
A person with a conventional mechanical hand prosthesis has the ability to control the grip of an object based only on visual or aural feedback. This is a problem because the wearer must discern the amount of pressure to apply to objects based on the deflection of a surface, the sound of the hand drive motor, or guessing on trial and error. If the grip is too tight, the object may be crushed or break, or, if too light, the object may be dropped. If the wearer is distracted or forgets that the hand is still holding the object, the lack of feedback could create a dangerous or embarrassing situation.
Most conventional electric control systems that drive the mechanical hand are simple designs which allow two conditions, either full speed or off. This makes it difficult for the wearer to accurately position the hand which affects gripping ability.
Conzelman, Jr. et al, U.S. Pat. No. 2,656,545, discloses a prosthetic device having a sensory apparatus for transmitting to the wearer of the artificial device an indication of contact that is made by the artificial member. In one embodiment, a bladder on the end of the finger of the prosthesis is connected by a flexible tube to a second bladder held by a harness to a normally sensitive part of the skin of the stump of the amputee. In another embodiment, a switch on the end of the finger of the prosthesis closes an electrical circuit in response to finger tip pressure and a vibrator disc held by a harness to a normally sensitive part of the skin vibrates in intensity relative to the finger tip pressure.
Patterson et al, U.S. Pat. No. 4,808,187, discloses a tactile stimulus receptor for use with a myoelectric prosthesis having a piezoelectric transducer positioned on the gripping fingers of the prosthesis which senses pressure resulting from gripping and converts the sensed pressure into electrical signals proportional to the pressure to a hydraulic motor and cylinder which is connected by a tube to a pressurizable cuff mounted on the wearer's forearm. The cuff constricts the forearm upon increased pressurization and reduces constriction upon reduced pressurization.
Fletcher et al, U.S. Pat. No. 3,751,733, discloses a prosthetic device including a socket for mounting the frame of the device on the stump of the amputee. A piezoelectric transducer and a temperature transducer are provided in flexible digits of the hand for sensing pressure and temperature. The transducers detect tactile stimuli and are connected through a power circuit to a pair of solenoids and a resistance heating element supported by a strap buckled about the stump. Tactile stimuli detected at the sensing devices are reproduced and applied to the skin of the appendage as a pinching and heating or cooling sensation for stimulating sensory organs.
Barry, U.S. Pat. No. 4,571,750, discloses the use of acoustic signals generated by muscles during contraction to generate signals responsive to muscle activity. The invention relates to a complex method of analyzing a human body and controlling prosthetic devices which use acoustic signals obtained from skeletal muscles alone and in combination with myoelectric signals.
Barkhordar et al, U.S. Pat. No. 4,650,492, relates to an artificial hand that comprise a palm member and thumb and finger members movable by an actuator. A microphone is used to pick up pressure waves resulting from a stick/slip motion of the object being picked up along the surface of the hand.
Giampapa, U.S. Pat. No. 4,770,662, discloses sonic frequency generators in electrical communication with pressure transducers in the digits of an artificial hand. Output signals in the form of voltage and sonic frequency are transferred to a bone stump and transmitted to the brain via the spinal column.
The present invention is distinguished over the prior art in general, and these patents in particular by a computerized electronic hand prosthesis apparatus and method utilizing input, feedback, control, and operating systems configurable to provide precise control and gripping forces corresponding to the particular capabilities and requirements of an individual wearer. An articulated prosthesis capable of exerting a mechanical gripping force contains a programmable microcomputer. Electrodes on the prosthesis contact muscles of the remnant portion of a limb and produce an electric command signal responsive to the myoelectric signal created by the wearer contracting and relaxing the muscles in the remnant portion. A drive motor in the prosthesis causes the prosthesis to exert a mechanical gripping force responsive and proportional to the electric command signal. Force sensors in the digits of the prosthesis detect the force exerted and produce an electric sensor signal responsive and proportional thereto. A motor driven vibratory device on the prosthesis engages the remnant portion of the limb adjacent sensory nerves and produces a feedback signal perceptible to the wearer which changes in vibratory pattern and amplitude at various selective grip forces. A communication port on the prosthesis is releasably connected to peripheral devices for exchanging data, diagnosing, correcting, or setting the operational parameters of the prosthesis. The electrodes, drive motor, force sensors, vibratory device, and communication port are controlled by the microcomputer.
SUMMARY OF THE INVENTION
It is therefore an object of the present invention to provide a prosthetic apparatus and method utilizing configurable input, feedback, control, and operating systems to transmit feedback signals representing the gripping force back to the wearer to allow precise positioning and gripping force control corresponding to the particular capabilities and requirements of an individual wearer.
It is another object of the present invention to provide a prosthetic apparatus and method utilizing control by the wearer to exert mechanical forces in the prosthesis and sensors in the prosthesis to transmit feedback signals representing the exerted forces back to the wearer in the form of vibratory stimuli which change in vibratory pattern and amplitude at various selective grip forces corresponding to the particular capabilities and requirements of an individual wearer.
Another object of this invention to provide a computerized electronic hand prosthesis apparatus and method utilizing configurable input, feedback, control, and operating systems and control by the wearer to exert a mechanical grip force and grip sensors in the hand digits to transmit feedback signals representing the gripping force back to the wearer in the form of vibratory stimuli which change in vibratory pattern and amplitude at various selective grip forces corresponding to the particular capabilities and requirements of an individual wearer.
Another object of this invention is to provide an articulated prosthesis to be worn by a living being which contains a programmable microcomputer having a variety of operating programs in memory storage corresponding to the particular capabilities and requirements of the individual wearer.
Another object of this invention is to provide a computerized electronic prosthesis which is easily operated by the wearer contracting certain muscles of the remnant portion of their limb to produce a myoelectric signal and receiving a non-irritating feedback signal easily perceived by the wearer which is representative of the mechanical force exerted.
Another object of this invention is to provide a computerized electronic hand prosthesis having a communications port connected with the microcomputer for releasably connecting the prosthesis to peripheral devices for exchanging data, monitoring, diagnosing, adjusting, correcting, or setting the operational parameters of the prosthesis.
A further object of this invention is to provide a computerized electronic hand prosthesis which will automatically detect and compensate for loss of mechanical gripping force without any action on the part of the wearer.
A still further object of this invention is to provide a computerized electronic hand prosthesis which is cosmetically superior, lighter in weight, and stronger than conventional prosthetic devices.
Other objects of the invention will become apparent from time to time throughout the specification and claims as hereinafter related.
The above noted objects and other objects of the invention are accomplished by a computerized electronic hand prosthesis apparatus and method utilizing input, feedback, control, and operating systems configurable to provide precise control and gripping forces corresponding to the particular capabilities and requirements of an individual wearer. An articulated prosthesis capable of exerting a mechanical gripping force contains a programmable microcomputer. Electrodes on the prosthesis contact muscles of the remnant portion of a limb and produce an electric command signal responsive to the myoelectric signal created by the wearer contracting and relaxing the muscles in the remnant portion. A drive motor in the prosthesis causes the prosthesis to exert a mechanical gripping force responsive and proportional to the electric command signal. Force sensors in the digits of the prosthesis detect the force exerted and produce an electric sensor signal responsive and proportional thereto. A motor driven vibratory device on the prosthesis engages the remnant portion of the limb adjacent sensory nerves and produces a feedback signal perceptible to the wearer which changes in vibratory pattern and amplitude at various selective grip forces. A communication port on the prosthesis is releasably connected to peripheral devices for exchanging data, diagnosing, correcting, or setting the operational parameters of the prosthesis. The electrodes, drive motor, force sensors, vibratory device, and communication port are controlled by the microcomputer.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an exploded isometric view of the components of the computerized electronic hand prosthesis apparatus in accordance with the present invention shown in an unassembled condition.
FIG. 2 is an isometric view of the basic computerized electronic hand prosthesis apparatus in the assembled condition.
FIG. 3 is a side elevation of the hand prosthesis with the basic components illustrated schematically in block diagram.
FIG. 4 is a schematic block diagram illustrating the variables, parameters, and software programs which can be changed to configure the microcomputer for hand control for a specific wearer to provide maximum wearer adaptation.
FIG. 5 is a graph illustrating the proportional control feature which allows the rate at which the hand opens or closes to be changed linearly and directly proportional to the analog signal being produced by the electrode.
FIG. 6 is a graph illustrating the on/off mode of operation which may be varied to turn on the motor at the maximum speed when the electrode signal goes above a preset threshold and turn the motor off when the signal goes below the threshold.
FIG. 7 is a graph illustrating the adjustable threshold voltage point at which the microcomputer will acknowledge a valid "open" or "close" signal.
FIG. 8 is a graph illustrating the adjustable upper limit of the gain for the "open" or "close" electrode.
FIG. 9 is a block diagram illustrating the method of operation of the computerized electronic hand prosthesis.
FIG. 10 is a block diagram illustrating the communication feature of the hand prosthesis.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to the drawings by numerals of reference, there is shown in FIGS. 1, 2 and 3, a preferred computerized electronic hand prosthesis apparatus 10. The components are shown in the unassembled condition in FIG. 1, and in the assembled condition in FIG. 2.
Unlike prior art two-piece lower arm prosthetic devices, the present invention may utilize a one-piece molded forearm member 11. The forearm member 11 is made by casting a mold of the stump of the patient and molding the rear or upper end of forearm member to conform to the remnant limb of the particular patient to be fitted and the lower portion of the forearm member to closely resemble the size and shape of the remaining or natural forearm. The upper end of the forearm 11 is thus fashioned into a custom sleeve or socket 12 and has a molded longitudinal slot 13 extending downwardly a short distance from the upper or socket end. Suitable padding material 14 is provided on the interior surface and surrounding edges of the socket portion 12. In use, the forearm 11 is removably attached to the wearer by pulling the remnant limb into the socket 12. The slotted upper portion of the socket 12 expands over the elbow, clasping the forearm member into place. The forearm is self-suspending and in most applications requires no straps or cables.
While a forearm member is described in the preferred embodiment, it should be understood that in some applications, a complete upper and lower arm member may be used and in other applications the hand prosthesis and accompanying electronic components (described below) may be attached to the wrist area of the remnant limb. The present invention may also be incorporated into other limbs, such as the upper or lower leg.
In the following discussion, the term "electrode" is used to describe the wearer input device, however, it should be understood that various input devices may be used, such as; myoelectric electrodes, sense resistors, variable resistors, pull switches, touch capacitance switches or plates, rocker switches, strain gauges, and similar devices. A dual electrode system is described as an example, wherein one electrode controls opening of the hand and the other electrode controls closing of the hand, however, it should be understood that a single electrode may also be used to either open or close the hand. The electrode type may be analog, digital, proportional, or linear.
The forearm member 11 is formed of lightweight material and is substantially hollow. A pair of electrodes 15 and 16 are mounted in the interior surface of the forearm 11. One electrode 15 is used for closing the hand and the other electrode 16 is used for opening the hand. The position of the electrodes 15 and 16 within the forearm 11 corresponds to the strong muscle groups in the stump of the limb covered by the socket end of the forearm and are activated by the wearer flexing a muscle. Muscle contractions on the medial side of the remnant limb close the hand and muscle contractions on the lateral side open the hand. As a muscle contracts it gives of an electrical stimulus which is received and amplified by the electrodes 15 and 16.
The exterior surface of the forearm member 11 has a cavity or recess 17 formed therein which removably receives a battery 18. In the preferred embodiment, the battery recess 17 is configured such that the battery 18 can be snapped into the recess 17 and enclosed by a removable cosmetic cover 19.
The electronic system is designed to operate over a full power and temperature range with an input voltage range of 4.5 to 7.5 volts without external regulators. A 6 volt nickel cadmium battery is preferred. Power supplied to components not operable in this range are pre-regulated to their proper voltage range through voltage regulators.
The electronic system does not require an on/off switch, but rather has an automatic "sleep mode" which reduces power 95% if the wearer does not make an active electrode signal for a variable period of time. Thus, the present system is a "warm" start rather than a "cold" start, and will be triggered upon a valid electrode input.
The battery 18 is electrically coupled to the electrodes 15 and 16 and a microcomputer (described below) through a wiring harness disposed within the interior of the forearm 11. A pair of insulated flexible leads 20 and 21 connected to the electrodes 15 and 16 extend through the wrist portion 11A of the forearm 11 and their outer ends are provided with modular plug connectors 22.
A motor driven vibratory device 23 is mounted in the exterior surface of the forearm member 11 near upper end for firm engagement with the skin of the remnant portion of the limb inside the socket end 12 of the forearm member. The motor driven vibratory device 23 converts electrical impulses into vibrations which are transmitted directly to the remnant portion of the limb for nerve stimulation as "feedback" signals to the wearer (described hereinafter). The motor driven vibratory device 23 is connected to a microcomputer (described below) through the leads 20 and 21 and modular connectors 22. The motor driven vibratory device 23 electrically and mechanically provides more vibration for the amount of power available than audio loud speakers or piezoelectric crystal devices. Preferably, the vibratory device 23 runs in the range of 30 cycles per second.
A communication port 24 is recessed in the exterior surface of the forearm member 11 near the wrist portion 11A and has a communication connector 25 mounted therein for releasably connecting the prosthetic hand to peripheral equipment. The communications connector 25 is joined by leads 20 and 21 and modular connectors 22 to the microcomputer housed in the prosthetic hand (described below). The wrist end 11A of the forearm member 11 is adapted to be connected to an electro-mechanical hand assembly 26. The communication port 24 allows the microcomputer housed in the hand to be connected to peripheral equipment, such as a modem, personal computer, or other equipment for exchange of data, and monitoring, diagnosing, adjusting, or correcting the operational parameters of the hand (described hereinafter).
It should be understood that the mechanical hand depicted in the drawings is for exemplary purposes only and that other types of mechanical hands may be used. Also, in some applications, a transmission may be incorporated into the gear mechanism and in other applications the drive motor may be connected directly to the movable fingers (conventional in the art).
An electro-mechanical hand frame 27 is mounted within a molded hand frame cover 28 which is configured to closely resemble the hand of the wearer in shape and size and substantially covers the hand frame 27. The hand frame 27 has a yoke portion 29 with an index finger support 30, a middle finger support 31, and a thumb support 32, each pivotally mounted on the yoke portion at their rearward ends. Resilient pads 33 are mounted on the tips of the support members. The hand frame 27, finger supports 30, 31, and thumb support 32 are formed of lightweight rigid material, such as aluminum. The supports 30, 31, and 32 are slightly curved and are received in the index finger 30A, middle finger 31A, and thumb 32A, respectively, of the molded hand frame cover 28. The index finger 30A, middle finger 31A, and thumb 32A, of the molded hand frame cover 28 are articulated or flexible to be moved by the respective enclosed support members 30, 31, and 32.
The supports 30, 31, and 32 are connected through gears (not shown) to an electric D.C drive motor 34 mounted on the hand frame 27 and pivot between a predetermined open position and a closed position where the distal ends, or tips, of the index finger 30A, middle finger 31A, and thumb 32A, of the molded hand frame cover 28 are brought together in a pinching mode.
The electric D.C. drive motor is driven by a series of on/off pulses, utilizing "Pulse Width Modulation" (PWM), described hereinafter, which allows more precise control over the speed and torque of the motor than conventional linear analog approaches. The frequency of the pulses and the voltage applied to the motor remain constant, however, the duty cycle ("on" to "off" ratio) of the "on" time may be varied. For example, if the motor is driven with 6 volts at a 50% duty cycle this is the same as applying 3 volts of DC to the motor.
Strain gauge elements 35, 36, and 37 are mounted on the rigid supports 30, 31, and 32, respectively. As the hand closes and touches an object, compression stress forces will be exerted on the surfaces of the finger and thumb supports 30, 31, and 32. The strain gauge elements 35, 36, and 37 sense the amount of stress in the finger and thumb supports and convert it to electrical signals. The electrical "sensor" signal created by the hand should operate based on input from the wearer's electrodes. Variable data affecting the operation from wearer to wearer is stored EEPROM memory. The microcomputer is a substantially self-contained system with as many of the required system components embedded as possible to eliminate external components.
The microcomputer 38 sends and receives signals and controls the power to drive the hand mechanisms. The electrical "sensor" signal from the strain gauges 35, 36, and 37 is amplified to a level which the microcomputer can use and the microcomputer converts it through an analog/digital converter to digital numbers which are stored in the microcomputer memory and used in the programs to calculate feedback, starting and stopping the motor, changing speeds etc. Preferably all the wiring connections go through the microcomputer board (electrodes, motor, vibratory feedback, strain gauges, etc.). In some applications the microcomputer board may be mounted in or on the forearm member 11.
A wrist connection 45 at the rearward end of the hand frame 27 extends outwardly from the rear or wrist portion of the molded hand frame cover 28 to be connected to the wrist portion 11A of the forearm 11. The modular plug connectors 22 and 44 are connected together and the hand frame 27 and surrounding molded hand frame cover 28 assembled thereon is joined by the wrist connection 45 to the wrist portion 11A of the forearm member 11. The molded hand frame cover 28, wrist connection 45, and lower portion of the forearm 11 is covered by an elastomeric flexible skin-like glove 45 for cosmetic purposes.
Having thus described the major mechanical components of the present invention, a brief overview of the configurable features, variables, parameters, and software programs which can be changed to configure the microcomputer to provide maximum hand control for a specific wearer and provide maximum wearer adaptation will be described followed by a detailed description of the operation of the system.
CONFIGURATION
Referring now to FIGS. 4, 5, 6, 7, and 8, the following paragraphs describe a number of variables, parameters, and software programs which can be changed to configure the microcomputer for hand control for a specific wearer to provide maximum wearer adaptation.
"MAXIMUM CLOSE SPEED" is a variable stored in memory that will limit the maximum speed that the motor can close the hand. This allows the hand closing speed to be preset to anywhere between 30% and 100% of the normal maximum speed with maximum input from the "close" electrode.
"MAXIMUM OPEN SPEED" is a variable stored in memory that will limit the maximum speed that the motor can open the hand. This allows the hand opening speed to be preset to anywhere between 30% and 100% of the normal maximum speed with maximum input from the "open" electrode.
"PROPORTIONAL CONTROL" (FIG. 5) allows the rate at which the hand opens or closes to be changed linearly and directly proportional to the analog signal being produced by the electrode. Thus, the hand has the capability of digital proportional control operation. This mode is configurable and may be turned off for certain applications. When in the "off" mode, the system will default to the "On/Off Control" mode.
"ON/OFF CONTROL" (FIG. 6) is a mode of operation which may be varied to turn on the motor at the maximum speed when the myoelectric electrode signal goes above a preset threshold and turns the motor off when the signal goes below the threshold. For example, the adjustable threshold may be set at 40% with signals above the 40% threshold turning the motor on and signals below the 40% threshold turning the motor off.
The "POWER SUPPLY" is an electric D.C. drive motor driven by a series of on/off pulses, or "Pulse Width Modulation" (PWM) which allows more precise control over the speed and torque of the motor than conventional linear analog approaches. The frequency of the pulses and the voltage applied to the motor remain constant. The duty cycle ("on" to "off" ratio) of the "on" time is varied. For example, if the motor is driven with 6 volts at a 50% duty cycle this is the same as applying 3 volts of DC to the motor.
"SINGLE/DUAL ELECTRODES" is the capability of the system to operate with dual electrodes or with a single electrode. In the dual electrode mode, one electrode controls opening of the hand and the other electrode controls closing of the hand. The single electrode operation can be used to either open or close the hand depending upon the "Voluntary Open/Close" selection. The electrode type may be analog, digital, proportional, or linear. This variable is configurable and is stored in memory.
"VOLUNTARY OPEN/CLOSE" is a configuration parameter which works in conjunction with the "Single/Dual Electrode" mode to automatically close or open the hand, depending upon the selection, when the input signal is above or below the threshold.
"OPEN ELECTRODE LOWER THRESHOLD" (FIG. 7) sets the voltage point at which the microcomputer will acknowledge a valid "open" signal. This can be used to eliminate nuisance activations due to movement or environmental noise. This variable is configurable and stored in memory.
"CLOSE ELECTRODE LOWER THRESHOLD" (FIG. 7) sets the voltage point at which the microcomputer will acknowledge a valid "close" signal. This can be used to eliminate nuisance activations due to movement or environmental noise. This variable is configurable and stored in memory.
"OPEN ELECTRODE UPPER LIMIT" (FIG. 8) sets the gain for the "open" electrode. It can be adjusted to a lower value to allow a wearer with a weak input signal to still operate the hand and the maximum configured speed. The microcomputer scales the input signal between the lower threshold and the upper limit to 0% and 100%, respectively. This allows the system to be adjusted to match the requirements and capability of each wearer. This variable is configurable and stored in memory.
"CLOSE ELECTRODE UPPER LIMIT" (FIG. 8) sets the gain for the "close" electrode. It can be adjusted to a lower value to allow a wearer with a weak input signal to still operate the hand and the maximum configured speed. The microcomputer scales the input signal between the lower threshold and the upper limit to 0% and 100%, respectively. This allows the system to be adjusted to match the requirements and capability of each wearer. This variable is configurable and stored in memory.
"PINCH FORCE CONTROL" is a variable which determines how much force a hand can place on an object. Typically, the hand will be set from 5 pounds of force to a maximum of about 20 pounds of force. If the option is not required, the default will be the maximum value. The force is determined by combining the average force between the fingers and thumb with the stall current of the motor. This variable is configurable and stored in memory.
"VIBROUS FEEDBACK" is an stimuli signal generated by a vibratory device and transmitted directly to the remnant portion of the limb for nerve stimulation. The preferred vibratory device is a motor driven vibratory device running in the range of 30 cycles per second which provides maximum vibration for the amount of power that is available.
"VIBROUS PRESENTATION" is Pulse Code Modulation (PCM) with the main frequency set to allow maximum penetration through the skin to nerve endings and reduce the amount of power consumed. The modulation is proportional to the amount of force being applied by the hand. When the hand starts closing, regardless of where it is, a vibratory signal is immediately sent to the output vibratory device to give the wearer a reference point to start from (meaning no pressure). When the minimum force is detected on any of the fingers or thumb, another vibratory signal is sent to the output vibratory device. As the force increases, the strength of the signal increases. The feedback signal changes at various grip forces on the hand to a different vibratory pattern and amplitude which is configurable. The frequency, amplitude, and Pulse Code Modulation (PCM) are adjustable.
"VIBROUS FREQUENCY" is the frequency of the output feedback signal. It preferably is in the range of 30 cycles per second. Preliminary testing has shown that it is easier to detect minor changes on the skin surface by leaving the amplitude and base frequency at a fixed level and allow the microcomputer to vary the duty cycle of the frequency. This way the signal allows better sensitivity.
"FREQUENCY SHIFT OPTION" is a significant signal shift which occurs when force is detected on either of the fingers and the thumb indicating that the hand is gripping an object as opposed to just touching or pushing something with a finger. The range of the duty cycle will be proportional to the strength of the force applied to the fingers or thumb. The amount of frequency shift required is determined through testing. The sensor signals may be averaged or the dominant signal may be used.
"VIBROUS REMINDER" is a change in the vibrous feedback signal which prevents the wearer from becoming numb or ignoring the feedback signal and also reduces the amount of power consumed. A timer turns off the vibrous feedback signal shortly after the hand stops moving and then delays for several seconds before exerting the signal again. The time delay and the modulation of the frequency shall change each time so as not to become repetitive and predictable.
"AUTOMATIC SHUTOFF" is a variable stored in memory which protects the batteries from extreme discharge and possible cell voltage reversal. This variable is a predetermined voltage value at which the system will terminate operation.
"POWER DOWN OPERATION" is a standby mode of operation to minimize current consumption when there is no electrode signal or force sensor signal present. If there is no electrode signal present and no force on the fingers and thumb, the microcomputer will transfer into the standby mode where the current consumption of all electronics will be approximately 10% of normal. When an electrode signal is detected the system would immediately go back into full operation. A time delay may also be incorporated before switching into a sleep mode, but the transition from sleep to active will be immediate.
"GRIP LOSS DETECTION" is a software program which monitors when the hand is losing the grip on an object. When it is determined that the hand is losing its grip on the object the motor is activated to close the hand back to the original grip pressures. This action is independent of other wearer controlled functions. The "Grip Loss Detection" function is enabled or disabled by the use of a configuration jumper, or an EEPROM configuration bit.
"GRIP LOSS PROGRAM" is a software program which detects when there is a grip and records sensing pressures. The hand is said to have a grip on an object when there is force detected between the thumb and any other finger. When the hand is in the "close" mode the program detects when this condition occurs and stores the pressures in memory. When the hand is directed to stop closing, the final force values are recorded. The program then continuously monitors all finger pressures and looks for significant changes in force. If the force between the two fingers shifts to equal the same average value then there is no grip loss. If the force drops in the thumb and any one finger there is a grip loss. When the grip loss is detected the microcomputer immediately drives the motor in the "close" direction to re-establish the pressures originally set by the wearer. Variables available are the time delay for activation of the "Grip Loss Detector" program and the speed of the motor. Options include driving the motor at a speed proportional to the rate of the drop in force.
"MOTOR STALL DETECTION" is a software program which monitors the range of voltage generated by the motor during the "drive off" period, linearizes the data, and interprets the force exerted by the hand. The direct current motor used in the prosthetic hand is also a generator. Thus, if the shaft is turned it will generate a voltage. The motor will typically consume three to ten times its normal running current when it stalls. Since the motor is driven with a series of on/off pulses, or Pulse Width Modulation (PWM) (described below), the shaft is turned while applying voltage and the Back Electromotive Force (BEMF) of the motor during the drive "off" period can be monitored. If the generator voltage is near the drive voltage then the motor has very little load. If the generator voltage is near zero this means the motor has a large load or is stalled. The software monitors this range and by linearizing the data can interpret the force exerted by the hand.
"DIAGNOSTIC PROGRAM" is a software program which allows the system to perform internal diagnostics upon each "turn on", power connection, or through an external command via the communications port. A series of diagnostic tests check the status of the components and the memory devices. Any abnormalities are stored in the EEPROM for later retrieval, and may be signaled to the wearer through the vibratory device or other suitable method. Any non-fatal errors should be flagged and self corrected if possible.
A "COMMUNICATION PROGRAM" is a software program which allows the microcomputer in the hand to exchange data via the communication port between peripheral devices, such as a modem, computer, or other equipment for monitoring, diagnosing, adjusting, or correcting the operational parameters of the hand. A remote host system can be connected to the hand to read or write all unprotected data in the microcomputer controller. The preferred data transference is in ASCII format to allow easy interfacing.
A "SECURITY" program may also be stored in memory which will look for a series of events to occur. If it detects that certain events did not occur it will immediately execute a program which will write a erasure program into RAM and then proceed to erase all EPROM (set all bits to 0) and all EEPROM and write a security message in a specific memory location. Any unauthorized attempt to remove the memory contents and apply power will delete or corrupt the program. Unauthorized persons attempting to read, evaluate, or remove the system programs will only find the manufacturer's name, copyright notification, and a security message.
OPERATION
A myoelectric signal is created by the depolarization of the cell membrane of individual muscle fibers during contraction. The electric currents associated with this depolarization and the subsequent repolarization produce measurable electric potential differences in tissues some distance away. It is these electric potentials, rather than the transcellular potentials, which are generated by the wearer to be detected by the electrodes and used as the input signal to open or close the hand.
In the following discussion, a dual electrode mode is described as an example, wherein one electrode controls opening of the hand and the other electrode controls closing of the hand, however, it should be understood that a single electrode can be used to either open or close the hand depending upon the "Voluntary Open/Close" selection. The electrode type may be analog, digital, proportional, or linear.
Referring again to FIG. 3, and additionally to FIG. 9, the system is activated by the wearer making a decision to hold an object and flexing a muscle to activate the "hand close" electrode" 15. The "hand close" electrode 15 detects, filters, and amplifies the myoelectric signal generated by the muscle and sends the analog signal to the microcomputer 38. The microcomputer 38 then activates the motor 34 to close the hand. When the hand starts closing, regardless of where it is, a vibratory signal is immediately sent to the output vibratory device to give the wearer a reference point to start from (meaning no pressure). When the minimum force is detected on any of the fingers or thumb, another vibratory signal is sent to the output vibratory device. As the force increases, the strength of the signal increases. The feedback signal changes at various grip forces on the hand to a different vibratory pattern and amplitude.
The speed of the motor, and in turn, the closing rate of the hand is directly proportional to the intensity of the myoelectric signal generated by the wearer. The hand will continue to close as long as the myoelectric signal is present until either the hand reaches maximum pinch force or the hand travels to its mechanical stop. When either of these conditions occur, the microcomputer will immediately terminate the drive motor.
The threshold voltage points at which the microcomputer will acknowledge a valid "open" or "close" signal are each configurable. These settings can be used to eliminate nuisance activations due to movement or environmental noise. These variables are preset and stored in memory. The upper limit for "open" and "close" gain for each respective electrode can be adjusted to a lower value to allow a wearer with a weak myoelectric signal to still operate the hand at the maximum configured speed. The maximum opening and closing speeds at which the motor closes or opens the hand and the proportion to intensity are each configurable and the maximum speed at which the motor is turned on or off when the myoelectric signal goes above or below a preset threshold is also a configurable variable. These variables are preset to fit the particular wearer and are stored in memory. These features allow the system to be adjusted to match the requirements and capability of each wearer individually.
As the hand continues to close and touches an object, compression stress forces are exerted on the surfaces of the finger and thumb support members 30, 31 and 32. The strain gauge elements 35, 36, and 37 mounted on the rigid supports sense the amount of stress in the finger and thumb supports and convert it to electrical "sensor" signals. The amplitude of the electrical signal created by the strain gauges is linear and is directly proportional to the stress forces applied by the fingers and thumb. The electrical "sensor" signals created will increase as the pinching force of the fingers and thumb on the object increases.
The electrical signals created by the strain gauges is filtered and converted to a digital value by the microcomputer 38. These values are analyzed by a software program stored in memory in the microcomputer. The program in the microcomputer monitors these "pinch force" signals and when they reach a preset point, will initiate the wearer feedback. The "pinch force" is a variable which determines how much force a hand can place on an object. Typically, the hand will be set from 5 pounds of pinch force to a maximum of about 20 pounds. The "pinch force" is determined by combining the average force between the fingers and thumb with the stall current of the motor. This variable is configurable and stored in memory.
The electrical signals created by the strain gauges is converted to digital signals and is fed to the motor driven vibratory device 23 in the form of a "vibrous feedback" signal and transmitted as vibrations directly to the remnant portion of the limb for nerve stimulation. Several variables are provided for the "vibrous feedback" signal. The "Pulse Code Modulation" (PCM) can be set with the main frequency to allow maximum penetration through the skin to nerve endings and reduce the amount of power consumed. The modulation is linearly proportional to the amount of force being applied by the hand. When the minimum force is detected on any of the fingers or thumb, a vibratory signal is sent to the vibratory device 23. The pulse duration of the signal is proportional to the maximum force exerted on the fingers and thumb. As the pinch force increases, the strength and repetition of the feedback signal increases. The frequency, amplitude, and "pulse code modulation" (PCM) are adjustable and stored in memory.
The frequency of the output feedback signal can also be adjusted. It preferably is in the range of 30 cycles per second. Preliminary testing has shown that it is easier to detect minor changes on the skin surface by leaving the amplitude and base frequency at a fixed level and allow the microcomputer to vary the duty cycle of the frequency. This way the signal allows better sensitivity.
Through testing, it is possible to determine a point at which a significant "sensor" signal shift occurs. This is a point at which a force is detected on either of the fingers and the thumb indicating that the hand is gripping an object as opposed to just touching or pushing something with a finger. The range of the duty cycle will be proportional to the strength of the force applied to the fingers or thumb. The amount of frequency shift required is determined through testing. The sensor signals from the electrodes may be averaged or the dominant signal may be used.
When the command signal to close the hand is terminated by the wearer, the hand movement is halted. The microcomputer 38 records the current forces on the fingers and thumb and after a preset time delay, terminates the continuous feedback signal. Every few seconds while the wearer grips the object, the microcomputer will drive the vibratory device with an intermittent varied signal, or "vibrous reminder". To prevent the wearer from becoming numb or ignoring the feedback signal, a change in the timing and modulation of the frequency is incorporated wherein a timer turns off the vibratory feedback signal shortly after the hand stops moving and then delays for several seconds before exerting the signal again. The time delay and the modulation of the frequency change each time so as not to become repetitive and predictable. This will occur often enough to remind the wearer that the object is still being gripped, but not long enough to become monotonous or cause excessive battery drain.
If while gripping an object the microcomputer 38 detects that a force change is occurring, it will invoke the "Grip Loss Detection" (GLD) program stored in memory. The GLD monitors and analyzes the pinch force signals and determines whether the grip is being lost or just that the weight of the object is shifting. If the GLD program determines that the hand is losing the grip, it will drive the motor to close the hand in an attempt to regain the original pinch forces and grip established by the wearer. This action is independent of other wearer controlled functions. Thus, the hand can operate independently of the wearer to compensate for grip loss, however, the hand will not increase the pinch forces beyond the point set by the wearer.
A "Grip Loss Program" (GLP) stored in memory detects when there is a grip and records sensing forces. The hand is said to have a grip on an object when there is pinching force detected between the thumb and any other finger. When the hand is in the "close" mode the program detects when this condition occurs and stores the pinching forces in memory. When the hand is directed to stop closing, the final force values are recorded. The program then continuously monitors all finger forces and looks for significant changes. If the pinch force between the two fingers shifts to equal the same average value then there is no grip loss. If the force drops in the thumb and any one finger there is a grip loss. When the grip loss is detected the microcomputer immediately drives the motor in the "close" direction to re-establish the pinch forces originally set for the wearer. The time delay for activation of the "Grip Loss Detector" program and the speed of the motor 34 are configurable variables stored in memory. The motor may be driven at a speed proportional to the rate of the drop in pinch force.
A "Motor Stall Detection" program stored in memory monitors the range of voltage generated by the motor 34 and the "Back Electromotive Force" (BEMF) of the motor during the drive "off" period, linearizes the data, and interprets the forces exerted by the hand. If the generator voltage (BEMF) is near the drive voltage then the motor has very little load. If the generator voltage (BEMF) is near zero this means the motor has a large load or is stalled. The software monitors this range and by linearizing the data can interpret the force exerted by the hand.
A predetermined "Automatic Shutoff" voltage variable is stored in memory which will terminate operation of the hand to protect the batteries from extreme discharge and possible cell voltage reversal.
When the wearer is finished holding or gripping the object, he or she will flex a muscle on the "open" electrode 16 which will create a myoelectric signal to open the hand. The hand will then open to release the object and continue to open as long as the myoelectric signal is generated, or until the hand is in the fully open position where the microcomputer controller will automatically shut off the motor to save battery power.
The hand has a standby mode, or "Power Down Operation" which is invoked to minimize current consumption when there is no electrode signal or force sensor signal present. If there is no electrode signal present and no pinch force on the fingers and thumb, the microcomputer will transfer into the standby mode where the current consumption of all electronics will be approximately 10% of normal. When an electrode signal is detected, the system will immediately return to full operation. A time delay may also be incorporated before switching into a sleep mode, but the transition from sleep to active will be immediate.
A "Diagnostic" program stored in memory allows the system to perform internal diagnostics upon each "turn on", power connection, or through an external command via the communications port. A series of diagnostic tests check the status of the components and the memory devices. Any abnormalities are stored in the EEPROM for later retrieval, and may be signaled to the wearer through the motor driven vibratory device or other suitable method. Any non-fatal errors are flagged and self corrected where possible.
Any detection of abuse of the hand, (constant high levels of motor current, multiple attempts to move the hand without success, excessive force on the sensors, etc.) are logged into memory for future retrieval and analysis.
A "Security" program in memory will look for a series of events to occur. If it detects that certain events did not occur it will immediately execute a program which will write a erasure program into RAM and then proceed to erase all EPROM (set all bits to 0) and all EEPROM and write a security message in a specific memory location. Any unauthorized attempt to remove the memory contents and apply power will delete or corrupt the program. Unauthorized persons attempting to read, evaluate, or remove the system programs will only find the manufacturer's name, copyright notification, and a security message.
Referring now to FIG. 10, the communication port 24 allows the microcomputer 38 in the hand to be releasably connected to peripheral equipment, such as a modem, computer, or other equipment for exchanging data, monitoring, diagnosing, adjusting, or correcting the operational parameters of the hand. Thus, any operating problems can be diagnosed and corrected, operational data can be gathered, and operating parameters preprogrammed into the microcomputer can be easily and quickly changed through a simple telephone hook-up. When a wearer receives the hand prosthesis, he also receives a small modem, a connection plug and a telephone connection. A laptop or other computer can also be connected to the communication port for initially configuring the system.
If the wearer has a problem with the hand, he can call the manufacturer of the hand prosthesis, hang up the telephone, plug the modem into the phone line, and plug the communications connector into the communication port. The manufacturer's remote computer can then call the hand via modem, and the patients hand will answer. The manufacturer can then perform diagnostic tests, determine where and if here is a problem or a battery failure and correct the problem over the phone by making corrections to the operating parameters where possible. This feature makes it possible to correct, adjust, and fine tune the gripping forces, electrode sensitivity, threshold levels, motor speed opening or closing, etc., and also periodically monitor the hand usage and operation with very little inconvenience to the wearer.
The "Security" program in memory will detect any unauthorized attempt to read, evaluate, or remove the system programs.
While this invention has been described fully and completely with special emphasis upon a preferred embodiment, it should be understood that within the scope of the appended claims the invention may be practiced otherwise than as specifically described herein.
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A computerized electronic hand prosthesis apparatus and method utilizing input, feedback, control, and operating systems configurable to provide precise control and gripping forces corresponding to the particular capabilities and requirements of an individual wearer. An articulated prosthesis is capable of exerting a mechanical gripping force and contains a programmable microcomputer. Electrodes on the prosthesis contact muscles of the remnant portion of a limb and produce an electric command signal responsive to the myoelectric signal created by the wearer contracting and relaxing the muscles in the remnant portion. A drive motor in the prosthesis causes the prosthesis to exert a mechanical gripping force responsive and proportional to the electric command signal. Force sensors in the digits of the prosthesis detect the force exerted and produce an electric sensor signal responsive and proportional thereto. A motor driven vibratory device on the prosthesis engages the remnant portion of the limb adjacent sensory nerves and produces a feedback signal perceptible to the wearer which changes in vibratory pattern and amplitude at various selective grip forces. A communication port on the prosthesis is releasably connected to peripheral devices for exchanging data, diagnosing, correcting, or setting the operational parameters of the prosthesis. The electrodes, drive motor, force sensors, vibratory device, and communication port are controlled by the microcomputer.
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BACKGROUND OF THE INVENTION
This invention relates to a glazing panel comprising clear glass panes held in spaced facing relationship and incorporating a coating on an exterior glass surface of the panel for solar shading purposes.
Such panels are known wherein one of the exterior glass faces bears a coating which is capable of screening off a proportion of incident solar radiation. When used as a window with the coated exterior face to the outside of the building the coating reduces the glare and/or the heating effect of strong sunlight at the building interior.
Such an external coating can be formed of one or more oxides. Oxide coatings can provide a useful shading effect against solar radiation while having an adequate visible light transmissivity to meet most glazing requirements. Such oxide coatings can have a fairly high abrasion resistance and they can be formed on large areas of glass with a high degree of uniformity. These potentialities of oxide coatings are well known in the art of coated glass manufacture and various oxide coatings are in actual use.
A disadvantage of such optical oxide coatings is the heating effect associated with their screening function. The solar shading afforded by such coatings is appreciably dependent on their absorption of light and/or infra-red radiation. This energy absorption results in heating of the coated pane and the re-emission of energy as long wavelength infra-red radiation. Some of this re-emitted energy is radiated towards the interior of the panel, i.e. towards the interior of the building, and consequently detracts from the overall shading efficiency of the panel.
The adverse effects of the energy absorption by the external coating can be reduced by screening off the infra-red radiation emitted internally from the coated exterior pane, e.g. by a suitable optical coating on the next pane. It is theoretically better however to coat the inside face of the oxide-coated pane itself in order to reduce the infra-red emission from that face. In practice however there are problems in reconciling the provision of such an internal coating with required performance specifications of the panel if these specifications require its luminous transmission factor to be high having regard to its total energy transmission factor.
As used in this specification the term "luminous transmission factor" denotes a ratio of the quantity of visible transmitted light to the quantity of incident visible light, such quantities being corrected integrations of the transmitted and incident light values respectively over the whole spectral range of visible light, the integrations being corrected to compensate for the spectral distribution of the radiant energy source and for the spectral sensitivity characteristics of the human eye. The measurements are made with a spectrophotometer and using a light source whose spectral composition is that of Illuminant D 65 as defined by the International Commission on Illumination (reference CIE 17 Sections 45-15-145). This illuminant represents daylight with a colour temperature of about 6504 K. The eye sensitivity correction factor applied is likewise that which is standardised by the International Commission on Illumination.
The term "total energy transmission factor" as used herein denotes the ratio of transmitted radiant energy to incident radiant solar energy. The term "energy absorption factor" as used herein denotes the fraction of incident radiant solar energy which is absorbed. For the determination of both of these factors use is made of a radiator whose spectral composition is that of direct sunlight at an elevation of 30° above the horizon. The spectral composition is given by Moon's Table for a mass of air equal to 2. The energy absorption factor of a coated glass pane as referred to in this specification, like the total energy transmission factor of a panel, is always measured with the face bearing the energy-absorbing coating directed towards the radiant energy source. The luminous transmission factor is not dependent on whether the face bearing said energy-absorbing coating is directed towards or away from the light source.
SUMMARY OF THE INVENTION
The present invention enables a panel comprising clear glass panes to have a very favourable combination of said luminous and total energy transmission factors to be achieved. The expression "clear glass" as used in this specification denotes glass of such composition that a 6 mm thick sheet of the glass has a luminous transmmission factor of at least 85%.
A panel according to the present invention is defined herebelow. The panel is characterised in that the external glass coating is an energy-absorbing oxide coating and in that a gold coating between 9 and 14.5 nm thick is present on the interior face of the pane bearing said oxide coating so that such gold coating is exposed to the interior of the panel.
The combination of coatings in accordance with the invention affords notable advantages. The use of gold for forming optical coatings is known per se but its use in the manner required by the invention enables a multiple glazing panel to possess a combination of properties which are distinctive and not attainable by panels produced in accordance with prior published proposals in this field. In particular, infra-red emissivity of the gold-coated face is reduced to a surprising degree in relation to the screening of visible light by the coating. A clear glass pane bearing on one side a gold coating between 9 and 14.5 nm in thickness can have a luminous transmission factor of at least 60% even with an emissivity of the gold coating of not more than 0.25. This advantage can be realised in a panel according to the invention without involving any objectionable modification of the colour of the panel viewed by reflected or transmitted light.
The attainment of the foregoing optical properties by using gold for the low emissivity coating is of importance from the manufacturing standpoint because gold coatings of the requisite thickness can be formed to comply with very high standards of uniformity by established coating techniques. The gold coating is resistant to ageing and, being within the panel, it is protected from mechanical damage.
Preferably the properties of said oxide coating are such that the clear glass pane and such coating together have an energy absorption factor of at least 16%. The benefits of using a gold coating in accordance with the invention are particularly significant in such cases.
Oxide coatings having good solar screening properties can as known per se nevertheless have a reasonably good visible light transmissivity. The relationship between the luminous transmission and total energy transmission factors of a panel according to the invention can therefore be very favourable.
In preferred embodiments of the invention, the glass panes and the coatings are composed so that the panel, when arranged with the oxide-coated face towards the radiant energy source, has a good energy absorbing property while also having a luminous transmission factor higher than its total energy transmission factor. The attainment of this condition, and substantially without modifying the apparent colour of the panel, is made possible by the employment of gold for the internal coating and by giving the gold coating a thickness within the range hereinbefore specified.
For the energy-absorbing oxide coating it is preferred to employ a coating comprising one or more metal oxides selected from: tin, titanium, cobalt, iron and chromium oxides, and most preferably such a coating which comprises a mixture of cobalt, iron and chromium oxides. It is for example suitable to employ such a three-constituent coating wherein the cobalt, iron and chromium oxides are in a ratio of 62:26:12 by weight. A neutral colour energy-absorbing coating with a favourable luminous transmission factor can be formed by using a mixture of cobalt, iron and chromium oxides and a coating thickness of from 20 to 100 nm and preferably from 30 to 50 nm.
Preferably the gold coating has a thickness between 9 and 12 nm. This narrower range is recommended for avoiding or keeping to a minimum any colour modifying effect of the coating.
In some embodiments of the invention there is an undercoating beneath the gold coating. The quality of the gold coating can be improved by applying a suitable subbing layer to the glass. Preferably bismuth oxide is used for such undercoating.
It is possible to overcoat the gold coating instead of leaving it exposed to the interior of the panel, while still realising for the panel as a whole a favourable relationship between its luminous transmission factor and its total energy transmission factor. Accordingly, the invention includes a panel incorporating the invention as hereinbefore defined but with the modification that the gold coating is overcoated by another light-transmitting layer or layers. A pane bearing such layers may have a luminous transmission factor greater than when using the gold layer alone. Preferably the gold-coated glass pane and the coating layers on its gold-coated face together have a luminous transmission factor of at least 60%. Preferred panels according to the said modification of the invention, when arranged with the oxide-coated face towards the radiant energy source, have a luminous transmission factor higher than their total energy transmission factor.
For forming an over-coating on the gold layer it is suitable to employ Bi 2 O 3 , ZnO, ZnS, or TiO 2 .
In the case that the gold coating is over-coated by one or more further light-transmmitting layers it is possible to achieve a relatively high luminous transmission factor in relation to a given total energy transmission factor while using a gold coating of a thickness which would not otherwise enable that condition to be achieved. Accordingly the present invention also includes a panel as defined herebelow. Such a panel is characterised in that the external coating is an energy-absorbing oxide coating, in that on the interior face of the pane bearing said oxide coating there is a second coating which comprises a layer of gold covered by at least one further light-transmitting layer; and in that the composition of the glass sheets and the compositions and thicknesses of said energy-absorbing coating and said second coating layers are such that the panel, when arranged with said oxide-coated face towards the radiant energy ssource, has a luminous transmission factor higher than its total energy transmission factor. The oxide coating in such a panel preferably has properties such that the oxide coating and the pane bearing it together have an energy absorption factor of at least 16%. Preferably the gold-coated pane and the coating layers on its gold-coated face together have a luminous transmission factor of at least 60%.
Suitable materials for use in over-coating the gold layer are specified above.
BRIEF DESCRIPTION OF THE DRAWING
Certain embodiments of the invention, selected by way of example, will now be described with reference to the accompanying drawing
FIG. 1 is a cross-sectional view of the basic structure of a panel according to the invention.
FIG. 2 is a cross-sectional detail view of a first embodiment of the structure of FIG. 1.
FIG. 3 is a cross-sectional detail view of a second embodiment of the structure of FIG. 1.
FIG. 4 is a cross-sectional view of a third embodiment of the structure of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The illustrated panel comprises two sheets of clear glass, 1, 2 held in spaced relation by a frame 3. The panel is intended to be used as a glazing unit with sheet 1 to the outside of the building.
Sheet 1 bears on its outer face an energy-absorbing light-transmitting coating 4. This coating is a metal oxide coating. It is responsible for a part of the solar shading property of the panel. The oxide coating and the glass sheet 1 are preferably composed so that they together have a luminous transmission factor of at least 40%, a total energy transmission factor of not more than 60% and an energy absorption factor of at least 16%.
The internal face of sheet 1 bears a gold coating 5. The sheet 1 and its gold coating together have a luminous transmission factor of at least 60%. A subbing layer 52, shown in FIGS. 2 and 3, e.g. a layer of bismuth oxide, may be provided beneath the gold coating. An overcoating may also be provided on gold coating 5. The overcoating may be a single layer 5b as shown in FIG. 3 or a plurality of layers 5b' and 5b" as shown in FIGS. 3 and 4.
The following Examples 1, 2, 4, 5 are examples of panels according to the invention and constructed as described with reference to the drawing. Example 3 is for comparison purposes.
EXAMPLE 1
The sheets 1 and 2 were sheets of ordinary clear float glass having a thickness of 4 mm and 8 mm respectively.
The energy-absorbing coating 4 was a mixture calculated as comprising 62% CoO, 26% Fe 2 O 3 and 12% Cr 2 O 3 and had a thickness between 35 and 45 nm. The energy absorption factor of sheet 1 together with the oxide coating was 22%.
The gold coating 5 had a thickness of 11-12 nm and was formed on top of a bismuth oxide subbing layer 1.5-2 nm in thickness. The gold coating had an emissivity of about 0.2 and the luminous transmission factor of the sheet 1 together with the gold coating was about 60%.
The panel as a whole had a luminous transmission factor of 24.1% and a total energy transmission factor (measured with coating 4 facing the radiant energy source) of 23.3%. A luminous transmission factor of 24.1%, considered in isolation, is not a high value but having regard to the total energy transmission factor of 23.3% it is appreciably higher than can be attained by using low emissivity coatings as hitherto proposed.
The panel was of neutral colour to ordinary observation, the gold coating having no perceptible colour modifying effect. The actual colour purity of the panel viewed in reflection was less than 3%. The term "colour purity" here refers to the colour purity reflected back from the sheet 1 when it is illuminated by Illuminant D 65 defined by the International Commission on Illumination (reference CIE 17 Section 45-15-145) from the side opposite said gold coating, the purity being determined in the manner therein specified.
EXAMPLE 2
The panel was the same as that according to Example 1 except that sheet 1 had a thickness of 6 mm and the gold coating 5 had a thickness of 9 nm. The gold coating had an emissivity of about 0.25. The sheet 1 and its gold coating together had a luminous transmission factor of 64%. The panel as a whole had a luminous transmission factor of 26.3% and a total energy transmission factor (measured with the oxide-coated face towards the radiant energy source) of 26.0%.
EXAMPLE 3 (COMPARATIVE)
The panel was the same as that according to Example 1 except that the gold coating 5 had a thickness of 7 to 8 nm. The sheet 1 and the gold coating together had a luminous transmission factor of 67%. The panel as a whole had a luminous transmission factor of 28.0% and a total energy transmission factor (measured with the oxide-coated face towards the radiant energy source) of 30.8%.
EXAMPLE 4
The sheets 1 and 2 were sheets of clear glass each 6 mm in thickness.
The energy-absorbing coating 4 was as in the preceding examples.
The coating 5 comprised an undercoating of Bi 2 O 3 , a gold coating and an overcoating of Bi 2 O 3 covering the gold coating. The thicknesses of those three coatings were 2 nm, 16 nm and 34 nm respectively. The panel as a whole had a luminous transmission factor higher than its total energy transmission factor. The attainment of this result, notwithstanding the presence of the relatively thick gold coating, was attributable to the presence of the Bi 2 O 3 overcoating. The actual values of the luminous and total energy transmission factors of the panel were 24% and 23% respectively.
Notwithstanding the use of a gold layer having a thickness of 16 nm the panel was of neutral colour to ordinary observation. The colour purity of the panel, measured as in the case of the panel according to Example 1, was not more than 3%. Because of the presence of the superposed interference layer, the gold coating could be increased in thickness up to about 16.5 nm without making it apparent to ordinary observation by the extent of its influence on the colour purity.
EXAMPLE 5
The sheets 1 and 2 were of clear glass and were respectively 4 mm and 6 mm in thickness.
The energy-absorbing coating 4 was again a three-constituent coating containing cobalt, iron and chromium oxides as indicated in Example 1. The thickness of this coating was again between 35 and 45 nm and the energy absorption factor of the sheet 1 and coating 4 was 22%.
The coating 5 was constituted by a 1 nm thick subbing layer of bismuth oxide with a 14 nm thick gold layer.
The sheet 1 and the bismuth oxide and gold coating 5 together had a luminous transmission factor of 52% and the gold coating had an emissivity of 0.09.
The panel as a whole had a luminous transmission factor of 20.6% and a total energy transmission factor of 18.7%. The colour purity of the panel measured as in the case of the panel according to Example 1 was 8%, the dominant wavelength of the reflected light being 578 nm.
In the foregoing Examples 1 to 5 the sheets 1 and 2 were sheets of untempered glass. One or both sheets can be tempered if desired.
EXAMPLE 6
The sheets 1 and 2 were of clear glass and were each 6 mm in thickness. The energy-absorbing coating 4 was as in Example 1.
The coating 5 was constituted by a 2 nm subbing layer of bismuth oxide with an 11 nm thick gold layer and an overcoating of bismuth oxide having a thickness of 31 nm.
The panel as a whole had a luminous transmission factor of 28.3% and a total energy transmission factor of 29.2% (measured with the coating 4 facing the radiant energy source).
The colour purity of the panel viewed in reflection (measured as in the case of the panel according to Example 1) was 4%, the dominant wavelength of the reflected light being 486 nm.
The colour of the panel viewed in reflection was slightly blue. The panel was slightly more blue to ordinary observation than a similar panel bearing the energy-absorbing layer only.
Such a panel affords a notable advantage: its colour (viewed in reflection) is the same as the colour (viewed in reflection) of a window basement constituted by a sheet of clear glass bearing on its back face a coating layer of neutral coloured enamel and on its front face, an oxide coating similar to coating 4.
Glazing panels according to the present example can thus advantageously be mounted in front wall of buildings in combination with such window basements to give to that wall a uniform colour, viewed in reflection. In the present example, sheets 1 and 2 are sheets of untempered glass, but one or both sheets can be tempered if desired.
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A glazing panel for transmitting radiant energy including visible light energy which includes first and second glass sheets supported in spaced relation. The first glass sheet has an oxide coated surface which defines an exterior surface of the panel and a gold coating on the surface which faces the second glass sheet.
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CROSS REFERENCE TO RELATED APPLICATION
[0001] PPA 61/619,450
SPECIFICATION
[0002] 1. Field of the Invention
[0003] The present invention generally relates to remotely monitored systems, and more particularly, to a computerized system that monitors portable remote units with RF or other electromagnetic connectivity and is connected to a central control and monitoring element that provides system level operations.
BACKGROUND
[0004] Both private and public monitoring services exist. These systems do provide a useful service but suffer from significant infrastructure costs. Alternatively, ad hoc solutions for monitoring such as messaging friends and/or acquaintances when in real or perceived danger may be used but this technique suffers from a significant probability of failure when needed due to its manual nature.
[0005] A number of prior art systems have been proposed for security systems with monitoring services. For example, U.S. Pat. No. 7,126,472 and U.S. Pat. No. 8,098,153 describe a method of providing emergency response to a user carrying a mobile device by routing alarm conditions to a contact identified in a database. However, those disclosures suffer from deficiencies including prioritization of contacts, a mechanism to escalate to third parties, allowing access to a full-functionality full-time operator type console, and a mechanism to collaborate amongst contacts.
SUMMARY OF THE INVENTION
[0006] This invention provides flexible provision of operators for a monitoring system. These systems typically have one or more control centers that communicate with a plurality of remote terminals. The systems operate semi-autonomously with only occasional but required human supervision and control based on alarm status or other atypical conditions. Typically these systems will escalate an alarm or abnormal event to a human monitoring station operator. This disclosure enhances this topology with the flexible allocation of the operator function to chosen third party(s) as required. This capability facilitates custom monitoring operations and affords the opportunity of reduced cost structures since a dedicated operator is not mandatory.
BRIEF DESCRIPTION OF THE DRAWINGS
[0007] FIG. 1 is a block diagram of the invention describing one embodiment of the system topology
[0008] FIG. 2 provides a flowchart of operator authorization
[0009] FIG. 3 describes a typical embodiment of an intervention including optional escalations.
DETAILED DESCRIPTION OF THE INVENTION
[0010] Referring to FIG. 1 , the system consists of one or more monitoring server(s) 10 connected to a plurality of portable remote units 20 , by direct or networked radio interfaces. Examples of radio interfaces would include, but not be limited to, cellular, PCS, WiFi, and WiMax. The portable remote units 20 will provide their status to the control and monitoring server(s) 10 . The monitoring server 10 will continuously make a determination of alarm conditions. Depending on system parameters an alarm indication may be handled autonomously by the system and/or the situation may be escalated to an operator for human intervention. This disclosure introduces to the state of the art the option of having the operator role 40 relayed to one or more chosen individual(s) for further action as opposed to a dedicated trained individual waiting for events. An operator 40 for a particular user gains access to the system through a secure login process 30 . Said ioperators will be notified of an event that requires intervention. More than one chosen individual may service a particular user as an operator.
[0011] For this disclosure, a chosen individual is defined as a person that has been authorized to act as an operator 40 for the monitoring system. At least one chosen individual and, optionally, a plurality of chosen individuals may be designated as an operator by the user of the system. FIG. 2 describes a typical flow chart to optionally register a particular individual as an operator. The user makes a selection of an individual as a candidate operator and said individual is contacted and invited to be an operator 100 . That contact is typically, though not exclusively, through electronic means such as e-mail, text messaging, or social networking. To facilitate the interaction, an overview of the operator role may also be sent with the invitation. If the candidate operator accepts the invitation, he/she will be registered with the system as an operator for the selected user and will be authorized to act as such 130 . The user is then informed of the decision of said candidate operator on participating as an operator 105 . Information is optionally sent to the new operator 110 and, as an additional option, monitoring server 10 login information may also be sent to said new operator. After the operator first logs in to the server with the supplied credentials the operator has the option to receive training on the system, including but not limited to typical use scenarios 120 . A log of that training may be held by the system for possible use in prioritization algorithms. The user may optionally designate classes of operator to allow a hierarchy of operators for prioritization of actions. FIG. 2 describes the registration process for an operator for a particular user. It is possible that an individual may be an operator for a plurality of users. An operator would have the option to opt out of the operator role at any time for any reason.
[0012] Referring to FIG. 3 , a typical use case scenario is described to illustrate core and optional elements of the disclosure. An alarm condition 200 triggers a notification to be sent to the set of individuals designated as operators 210 . The notification would be sent electronically, typically but not exclusively as an e-mail or text message with a link to the monitoring server or as an alert to connect to the server. Said notification may be repeatedly sent to the operator community to improve the likelihood of a positive response. At the time of the notification a timer would be started by the server application that would be reset by the response of at least one operator 220 . If the timer expires, an escalation procedure would be initiated by the server that could notify the user that no operator has responded and that the planned next steps by the server are being initiated 230 . The consequences of said escalation 240 would be dependent on the service level of the user's contract or previous choice(s) of the user and may include notifying emergency services organizations with details of the situation as known by the server 10 , or forwarding to a paid monitoring service. If at least one operator responds to the notification the operator alarm handling state would be entered 250 .
[0013] The first operator to respond would be given operator control of the situation by the server 10 . The operator would typically be able to monitor the state of the user based on information available on or through the Monitoring Server 10 , including but not limited to location, biometrics, audio, video, and other sensors, optionally communicate with the user 20 , and also escalate the situation to a paid monitoring service or government emergency services. If a plurality of operators respond all responding operators would typically have visibility to the other operators that have responded and, optionally, those operators that have not responded. At that point options would be available to have operators with higher authorization or aptitude take control. The protocol for control can be based on a number of parameters including pre-selection of authorization levels by the user, mutual agreement (allow handoff of control), first respondent leads, or other means. If there is a plurality of responding operators the system can provide the means to collaborate amongst the operators, including chat and other methods that may or may not include the user. An operator that is logged on may have the option to invite other operators, that may be known to said operator, to join the monitoring session by separate login.
[0014] As an outcome of the operator intervention 250 , a decision is made by the operator(s) 260 on the state of the alarm. If the dangerous situation still exists an escalation state may be entered 270 which would typically involve emergency services such as 911 or local security. Conversely, if the dangerous situation is resolved the operator may clear the alarm 280 .
[0015] For every alarm condition the monitoring server shall log the events for subsequent analysis.
[0016] While the foregoing written description of the invention enables one of ordinary skill to make and use what is considered presently to be the best mode thereof, those of ordinary skill will understand and appreciate the existence of variations, combinations, and equivalents of the specific embodiment, method, and examples herein. The invention should therefore not be limited by the above described embodiment, method, and examples, but by all embodiments and methods within the scope and spirit of the invention.
[0017] The advantages of the present invention include, without limitation, the opportunity to provide monitoring services by a plurality of individuals with more detailed knowledge of the user and their situation than could be afforded by a generic monitoring service. The invention also affords the opportunity of a community based collaborative solution with lower infrastructure and monitoring costs.
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A monitoring service is described that allows flexible response through operators taken from a group of chosen individuals. When an alarm state is triggered the chosen individuals may act collaboratively as operators to manage alarm conditions for a particular user.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an assembly and a method for using the assembly in cell culture production. In particular, the assembly comprises a receptacle, a slide and means for separating the receptacle from the slide.
2. Description of Related Art
It is frequently desirable in medical laboratory practice as well as in biological research to grow various bacteria, cells or tissues in particular media and then to examine the resulting growth. A particular use of this technique is in virology laboratories where host cells are grown and then used to detect viral activity.
Typical apparatus useful for carrying out biological reactions or growth, such as growing tissue cultures is described in U.S. Pat. No. 3,726,764. The apparatus in U.S. Pat. No. 3,726,764 is a chamber attached to a glass slide with a liquid-impermeable seal. A special tool is wedged into the seal to separate the chamber from the glass slide.
A common problem which has confronted users of typical apparatus as described in U.S. Pat. No. 3,726,764 is that a separate tool to remove the chamber from the slide is not convenient and in spite of the high level of skill and care in separating the chamber and the slide, the potential for not shattering the glass slide is not always assured, and therefore, contamination of the cells on the slide is also not assured.
With the increased emphasis on the efficacy of medical and research products, a need exists for an improved apparatus for effectively and efficiently carrying out cell culture production. The improved apparatus would better protect the person carrying out the procedure and would be comparatively simple and inexpensive to manufacture as compared to available devices.
SUMMARY OF THE INVENTION
The present invention is a culture slide apparatus for carrying out biological reactions or growth therein, such as growing tissue or cell cultures.
The apparatus preferably comprises a base member, a cooperable receptacle comprising a plurality of chambers, means for removably attaching the receptacle to the base member and means for separating the base member from the receptacle. Desirably, the apparatus further comprises a lid for covering the opening of the receptacle.
Preferably the receptacle comprises a forward section and a rearward section and sidewalls that extend from a top surface to a bottom surface, wherein the bottom surface is removably mated with the base member. Most preferably, the bottom surface of the receptacle is removably attached to the base member with a liquid-impermeable seal. Preferably the liquid-impermeable seal may be comprised of a silicon or acrylate based composition as well as organopolysiloxane elastomers. A means for separating the base member from the receptacle is most preferably a movable lever. Desirably the lever is attached adjacent to the rearward section of the receptacle. The lever may be used to provide appropriate force between the receptacle and the base member to separate them.
Most preferably, the base member is a microscope slide. The base member and receptacle are most preferable made of glass or plastic.
To carry out biological reactions or growths in the apparatus, a liquid tissue culture medium is placed into the receptacle that is in contact with the base member. The medium is incubated to allow the tissue culture to grow and to attach to the base member. The liquid medium is then removed from the receptacle, and the receptacle is removed from the base with assistance from the lever. The tissue culture growth on the base can then be treated as desired and microscopically examined. This apparatus is also useful as an anaerobic chamber or as a blood culture chamber for microbiological assays.
A feature of the invention is its ease of use, in that the receptacle is easily removable from the base by the lever without the need to have a separate tool to wedge between the receptacle and the slide and that detachment forces are substantially reduced. Another feature of the invention is that the assembly is substantially self-contained in that the lever is attached to the assembly. Also, since the apparatus may be made from optically clear plastic, it may be easily disposable. Furthermore, the apparatus of the present invention improves the methods for carrying out biological reactions on slides by maintaining the integrity of the biological reaction due to the means for separating the chamber from the base member.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a culture slide apparatus.
FIG. 2 is a cross-sectional side view of the culture slide apparatus of FIG. 1 taken along lines 2--2.
FIG. 3 is a side view of the culture slide assembly of FIG. 1 illustrating the movement of the lever.
FIG. 4 illustrates the removal of the receptacle from the base member by the lever.
FIG. 5 illustrates the removal of the lever at the perforated edges.
FIG. 6 is a perspective view of a four chamber culture slide apparatus, illustrating an additional embodiment of the invention,
FIG. 7 is a perspective view of a six chamber culture slide apparatus, illustrating an additional embodiment of the invention.
DETAILED DESCRIPTION
While this invention is satisfied by embodiments in many different forms, there is shown in the drawings and will herein be described in detail, the preferred embodiments of the invention, with the understanding that the present disclosure is to be considered as exemplary of the principles of the invention and is not intended to limit the invention to the embodiments illustrated. Various other modifications will be apparent to and readily made by those skilled in the art without departing from the scope and spirit of the invention. The scope of the invention will be measured by the appended claims and their equivalents.
The preferred apparatus of the present invention is illustrated in FIG. 1 wherein apparatus 10 comprises a base member 12, a receptacle 14, a lever 16 which is movable and a lid 18.
Base member 12 has a planar upper surface 20 and opposing ends 22 and 24 which are normal to surface 20. Upper surface 20 of base member 12 is flat to form a mating surface for receptacle 14. Base member 12 is preferably a microscope slide. Such microscope slide is preferably fabricated from soda glass which has been cleaned to remove oils, greases, surfactants, abrasives or other materials inhibitory to biological or bacterial growth. Alternatively, the microscope slide may be fabricated from plastic. Such plastic materials may include polystyrene and the like.
Receptacle 14 is located near end 24 and mates against surface 20 of base member 12 so as to leave a substantial portion 30 of surface 20 exposed near end face 22. This free surface area 30 can be etched so as to render it capable of receiving appropriate identification markings, such as an appropriate label.
Receptacle 14 comprises opposing longitudinal sidewalls 34 and 36 and opposing transverse sidewalls 38 and 40 that define an open bottom 42 and an open top 44. The sidewalls extend from a top surface 46 to a bottom surface 48. At the bottom surface is a peripheral outwardly directed flange 50 surrounding bottom opening 42. Receptacle 14 further comprises a partition 51 that is parallel to and spaced equidistant from sidewalls 38 and 40 so as to form two chambers 53 and 55,
As shown in FIG. 2 lever 16 comprises a rearward end 52, and a forward or working end 54. Rearward end 52 and forward end 54 of lever 16 meet at pivot position 56. Rearward end 52 is attached to flange 50 along sidewall 40 of receptacle 14. The lever is attached to the receptacle in such a way that it can be moved in a substantially vertical up or down direction.
As shown in FIG. 2, lid 18 is capable of fitting over and closing the open top of the receptacle and is easily removable.
Receptacle 14 is preferably formed from transparent polymer materials. Such materials include, but are not limited to, polystyrene, polypropylene, celluloid, polymethacrylate and polymethylmethacrylate,
In the fabrication of the apparatus of the present invention, bottom surface 48 is removably attached to surface 20 of base member 12 near end face 24 by suitable means such as by an adhesive. Such adhesives include silicons or acrylates.
The principal criteria for a useful adhesive is that it provides desired removably adhesive characteristics between receptacle 14 and base 12, provides a liquid-impermeable seal, is substantially non-toxic to biological material subsequently employed in the apparatus, does not act as a source of growth for undesirable :microorganisms and reduces the amount of detachment forces required to separate the receptacle from the base.
As shown in FIG. 3, the lever may be activated wherein manual force is applied to the working end toward the upper surface of the base so that the pivot position contacts the upper surface of the base. This motion allows the working end of the level to exert force on the flange and bottom surface of the chamber in an upward direction, so as to disengage the receptacle from the base. The receptacle may be removed from the base by using the lever as shown in FIG. 4.
Lever 16 may be made of plastic or other flexible material. Optionally, the lever may be removed from the receptacle at the perforated edges 60 between rearward end 52 and sidewall 40 of the receptacle as shown in FIG. 5.
The apparatus of the present invention may be employed in the following manner to grow for example tissue cultures. The lid is removed from the receptacle. The desired liquid tissue culture medium containing a suspension of cells to be grown is then placed into the receptacle. The apparatus is then placed in a suitable incubator and is incubated under well-known conditions to carry out the tissue culture growth. If desired, suitable treatment may be carried out on the cells and medium during this growth to achieve cytopathology changes in the cells. At the conclusion of the growth period a mass of tissue cells is attached to base. The tissue culture medium can then be removed from the chamber by aspiration. The receptacle is then removed from the base by applying manual force to the lever as shown in FIG. 3 and removing the receptacle as shown in FIG. 4. The mass of tissue cells attached to the base is then rinsed and fixed on the base, and the affixed tissue culture is then treated with an appropriate stain to stain the culture.
While the chamber described above has four-sides, it is understood that apparatus of the present invention can employ more or less sides as well as other geometric shapes, such as circular. Further, it is understood that the present invention can contain any desired number of chambers.
FIGS. 6-7 are further embodiments of the invention that include many components which are substantially identical to the components of FIGS. 1-5. Accordingly, similar components performing similar functions will be numbered identically to those components of FIGS. 1-5, except that a suffix "a" will be used to identify those similar components in FIG. 6 and a suffix "b" will be used to identify those similar components in FIG. 7.
As illustrated in FIG. 6, a further embodiment of the invention includes a four chamber apparatus 70 having a base member 12a, a receptacle 14a, a lever 16a and a lid 18a. Receptacle 14a further includes four chambers 72, 74, 76 and 78 that are formed by partitions 80 and 82.
As illustrated in FIG. 7, a further embodiment of the invention includes a six chamber apparatus 90 having a base member 12b, a receptacle 14b, a lever 16b and a lid 18b. Receptacle 14b further includes six 92, 94, 96, 98, 100 and 102 that are formed by partitions 104, 106 and 108.
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The present invention is a culture slide assembly having a base member, a cooperable receptacle removably attached to the base and means for separating the receptacle from the base. Preferably, the assembly may be used for carrying out biological reactions or growth therein, such as growing tissue or cell cultures.
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BACKGROUND OF THE INVENTION
Antioxidants for polyether polyols and polyurethane foams prepared therefrom are well known and include hindered phenols, phenothiazines, mixtures of hindered phenols with phenothiazines or phosphoric acid, mixtures of 2,6-ditertiarybutyl-4-methyl phenol and a dialkyldiphenyl amine, mixtures of a hindered phenol and 4,4'-bis(α,α-dimethylbenzyl)diphenyl amine and mixtures of 2,6-ditertiarybutyl-4-methyl phenol, p,p'-dioctyl diphenyl amine and a phenothiazine.
Because of fluctuation and/or availability of the component materials it is desirable to find ways to decrease the quantity of antioxidant necessary to effectively stabilize the polyol and polyurethane against oxidative degradation and the foams prepared therefrom from scorching.
It has now been unexpectedly discovered that polyether polyols stabilized with a synergistic combination of certain hindered phenols and 4,4'-bis(α,α-dimethylbenzyl) diphenyl amine with a phenothiazine compound. The improvement is greater stability to the polyol against oxidative degradation at the same level of antioxidant or reduced levels of antioxidant for the same amount of stability.
SUMMARY OF THE INVENTION
One aspect of the present invention is directed to an improvement in a polyether polyol or mixture of polyether polyols stabilized against oxidative degradations with a stabilizing quantity of a synergistic composition containing
(A) from about 15 to about 85, preferably from about 25 to about 75 percent by weight of a sterically hindered phenolic antioxidant and
(B) from about 85 to about 15 and preferably from about 75 to about 25 percent by weight of 4,4'-bis(α,α-dimethylbenzyl)diphenyl amine,
the improvement which comprises substituting for part of either component (A) or (B) or a part of each of components (A) and (B), from about 25 to about 1000, preferably from about 50 to about 500 parts per million parts of polyether polyol of a phenothiazine compound represented by the formula ##STR1## wherein each R is independently hydrogen or an alkyl group having from 1 to about 12 carbon atoms.
The present invention also pertains to polyurethane foams prepared from the aformentioned polyether polyol.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
Suitable sterically hindered phenolic antioxidant compounds which can be employed herein include, for example,
2,4-dimethyl-6-octyl phenol,
2,6-ditertiarybutyl-4-methyl phenol,
2,6-ditertiarybutyl-4-ethyl phenol,
2,6-ditertiarybutyl-4-n-butyl phenol,
2,2'-methylene bis(4-methyl-6-tertiarybutyl phenol),
2,2'-methylene bis(4-ethyl-6-tertiarybutyl-phenol),
2,4-dimethyl-6-tertiarybutyl phenol,
4-hydroxymethyl-2,6-ditertiarybutyl phenol,
n-octadecyl-beta (3,5-ditertiarybutyl-4-hydroxyphenyl)
propionate, mixtures thereof and the like.
Particularly suitable phenothiazine compounds which can be employed herein include, for example,
phenothiazine, 2-methylphenothiazine, 3-octylphenothiazine,
2,8-dimethylphenothiazine, 3,7-dimethylphenothiazine,
3,7-diethylphenothiazine, 3,7-dibutylphenothiazine,
3,7-dioctylphenothiazne, 2,8-dioctylphenothiazine,
mixtures thereof and the like.
The polyether polyols which can be stabilized with the antioxidant composition of the present invention include those having from 2 to about 8 OH groups. Such polyols are disclosed by and methods for their preparation are given in POLYURETHANES: CHEMISTRY AND TECHNOLOGY II. TECHNOLOGY by Saunders and Frisch, Interscience Publishers, 1964. Also described therein are polyurethane foams and methods for their preparation.
Particularly suitable polyether polyols include those prepared by reacting an initiator compound having 2 to about 8 hydroxyl groups with an alkylene oxide or mixtures of such oxides, said polyols having molecular weights of from about 250 to about 10,000, preferably from about 2,000 to about 8,000.
Suitable initiator compounds include, for example, ethylene glycol, propylene glycol, water, butane diol, hexane diol, glycerine, trimethylol propane, hexane triol, penaerythritol, sucrose, mixtures thereof and the like.
Suitable alkylene oxides include, for example, 1,2-propylene oxide, ethylene oxide, 1,2-butylene oxide, 2,3-butylene oxide, styrene oxide, epichlorohydrin, epibromohydrin, mixtures thereof and the like.
The synergistic antioxidant compositions are employed in quantities of at least 10 parts per million (ppm) based upon the polyether polyol, preferably from about 500 to about 100,000, most preferably from about 1500 to about 5,000 ppm.
The following examples are illustrative of the present invention but are not to be construed so as to limit the scope thereof in any manner.
The stability of the polyols containing the various antioxidant systems was determined by placing the samples in a DuPont differential scanning calorimeter, Model 990 Thermal Analyzer and Module, at the indicated temperature and the induction period (time to initiation of oxidative decomposition) was recorded.
In the stability determination, the polyol samples weighing 10 mg±0.2 mg were placed in an aluminum pan containing a disc of 100 mesh stainless steel wire screen in the bottom of the pan. The aluminum pan containing the sample to be tested was placed in a differential scanning calorimeter cell along with a reference pan containing only the wire screen. The differential scanning calorimeter cell was purged with nitrogen for five minutes after it was closed. The cell was brought up to the isothermal temperature as quickly as possible without overshooting the desired temperature, usually 3 to 4 minutes. When the desired temperature was reached, the nitrogen was turned off and oxygen was introduced into the cell. When the oxygen flow rate reached 50 cc/minute, the recorder was started. Time was recorded on the X axis of the recorder, the temperature profile of the run was recorded on the Y axis, and the energy emitted or absorbed by the sample was recorded on the Y' axis. The induction period (time between introduction of oxygen into the cell and the time of initiation of oxidative decomposition) was determined by locating the point of interception of the baseline (X axis) and the slope of the exotherm deflection (Y' axis). The longer the induction period of the sample, the more stable was the sample.
EXAMPLE 1
Various levels of 2,6-ditertiarybutyl-4-methyl phenol, 4,4'-bis(α,α-dimethylbenzyl)diphenyl amine and phenothiazine were employed to stabilize a polyether polyol against oxidative degradation. The polyol employed was the reaction product of a mixture 92 wt. percent propylene oxide and 8 wt. percent ethylene oxide with a glycerine-propylene oxide reaction product having a molecular weight of about 450, the resultant polyol having a molecular weight of about 3000 hereinafter designated as polyol A.
Resistance to foam scorch was determined by preparing low density flexible foam with the polyols containing the various antioxidant systems and then subjecting these foams to a scorch test. The foams were prepared by a one-shot process using the following formulation:
______________________________________(1) 3000 molecular weight polyether polyol A 200 grams(2) Water 10.4 grams(3) L-540 Silicone surfactant 2.4 grams(4) Niax A-6 Amine Catalyst 0.250 grams(5) T-9 Stannous octoate 0.300, 0.350, or 0.400 grams(6) 80/20 mixture of 2,4-2,6-toluene diisocyanate (120 Index) 141.9 grams______________________________________
The first five components of the formualtion were mixed at 2000 rpm in a one quart Dixie cup for 25 seconds. The toluene diisocyanate was added to the cup and the components were mixed for an additional 5 seconds at 2000 rpm. Immediately after the second mix the formulation was poured into a 10 inch×10 inch×4 inch pastry box. The foam was allowed to rise and at 300 seconds from the start of the second mix the foam bun was placed into a preheated microwave oven for 4 minutes. The microwave oven had been calibrated so that 400 grams of water would increase 44° C. in temperature when heated for 4 minutes. At the end of the microwave cure the foam bun was placed in a conventional air circulating oven, controlled at 100° C., for 30 minutes. The foam buns were then allowed to cure at room temperature for 18 hours.
After a final cure of the foam buns, a one inch thick slice was cut parallel to the rise from the center of each bun. Each foam slice was then placed on a light box and the color of the foam was observed. The breathability (airflow) in the direction of foam rise was measured on a 2 inch×2 inch×1 inch foam sample taken from the center of the remaining portion of the foam bun.
One foam bun was prepared at each of the three stannous octoate levels with each polyol evaluated in the scorch test. The degree of foam scorch is related to the breathability (a relative measure of the open cell content) of the foam which is related to the amount of stannous octoate in the formulation. In this scorch test, the degree of scorch increased with the increased breathability. When the same base polyol is used in the foam formulation equivalent air flow values are obtained at a constant stannous octoate level. Therefore the resistance to scorch was compared at equivalent air flow values. The degree of scorch is also related to the absolute humidity and only the foams made under the same humidity conditions are comparable.
The results of the stability and scorch resistance determination for this example are presented in Table I. In this table "BHT" stands for 2,6-ditertiarybutyl-4-methyl phenol, "DMBDPA" stands for 4,4'-bis(α,α-dimethylbenzyl)diphenyl amine, "PTZ" stands for phenothiazine, and "I.P." stands for induction period. The foam appearance was rated as follows:
0 White, no discoloration
1 Very slight yellow discoloration
2 Light yellow discoloration
3 Yellow discoloration
4 Yellow to light brown discoloration
5 Yellow brown discoloration
6 Dark yellow brown discoloration
7 Opaque dark brown appearance
8 Charred dark brown with foam deterioration
9 Severe scorch, the foam actually started to smolder
TABLE I__________________________________________________________________________ AverageAntioxidant Level, I.P. at Foam Appearance Rating Appear-Sampleppm 170° C., (@ Various T-9 Wts.(gms).sup.1 anceNumberBHT DMBDPA PTZ min. 0.300 0.350 0.400 Rating__________________________________________________________________________1.sup.23000 1500 -- 22.9 5 4 3 42.sup.22000 1000 -- 15.8 9 7 5 73.sup.31900 1000 100 24.9 5 4 3 44.sup.32000 900 100 27.5 5 4 3 45.sup.2-- -- 100 11.5 9 9 8 8.7__________________________________________________________________________ .sup.1 These foam samples were prepared when the absolute humidity ranged frm 99 to 102 grains of water per pound of dry air. .sup.2 Comparative Experiment. .sup.3 Example of the present invention.
EXAMPLE 2
The polyether polyol described in Example 1 was stabilized with 3300 ppm total antioxidant while the amounts of 2,6-ditertiarybutyl-4-methyl phenol, 4,4'-bis(α,α-dimethylbenzyl)diphenyl amine and phenothiazine in each composition were varied. These polyol samples were then evaluated as described in Example 1 and the data is presented in Table II.
TABLE II__________________________________________________________________________ AverageAntioxidant Level, I.P. at Foam Appearance Rating Appear-Sampleppm 170° C. @Various T-9 Wts.(gms).sup.1 anceNumberBHT DMBDPA PTZ min. 0.300 0.350 0.400 Rating__________________________________________________________________________6.sup.22200 1100 -- 14.7 9 7 5 77.sup.32150 1100 50 23.5 9 5 4 68.sup.32200 1050 50 20.6 7 5 3 59.sup.32100 1100 100 28.1 5 3 3 3.710.sup.32200 1000 100 30.1 5 3 3 3.7__________________________________________________________________________ .sup.1 These foam samples were prepared when the absolute humidity ranged from 98 to 103 grains of water per pound of dry air. .sup.2 Comparative Experiment. .sup.3 Example of the present invention.
EXAMPLE 3
The polyether polyol described in Example 1 was stabilized with 3000 ppm total antioxidant while the amounts of 2,6-ditertiarybutyl-4-methyl phenol, 4,4'-bis(α,α-dimethylbenzyl)diphenyl amine and phenothiazine in each composition were varied. These polyol samples were then evaluated as described in Example 1 and the data is presented in Table III.
TABLE III__________________________________________________________________________ AverageAntioxidant Level, I.P. at Foam Appearance Rating Appear-Sampleppm 170° C., @ Various T-9 Wts.(gms).sup.1 anceNumberBHT DMBDPA PTZ min. 0.300 0.350 0.400 Rating__________________________________________________________________________11.sup.21500 1500 -- 14.5 9 8 7 812.sup.31450 1500 50 20.2 5 7 5 5.713.sup.31500 1450 50 23.1 5 3 6 4.714.sup.31400 1500 100 26.8 5 6 3 4.715.sup.31500 1400 100 28.4 5 3 3 3.7__________________________________________________________________________ .sup.1 These foam samples were prepared when the absolute humidity ranged from 66 to 78 grains of water per pound of dry air. .sup.2 Comparative Experiment. .sup.3 Example of the present invention.
EXAMPLE 4
The polyether polyol described in Example 1 was stabilized with various amounts of 2,6-ditertiarybutyl-4-n-butyl phenol, 4,4'-bis(α,α-dimethylbenzyl) diphenyl amine, and phenothiazine to demonstrate the utility of this invention while using a different type of hindered phenolic antioxidant. The total stabilizer level was held constant at 3600 ppm. These polyol samples were evaluated as described in Example 1. The data for this example is presented in Table IV where "DTBNBP" stands for 2,6-ditertiarybutyl-4-n-butyl phenol and all other abbreviations are the same as defined in Example 1.
TABLE IV__________________________________________________________________________ AverageAntioxidant Level, I.P. at Foam Appearance Rating Appear-Sampleppm 170° C., @ Various T-9 Wts. (gms).sup.1 anceNumberDTBNBP DMBDPA PTZ min. 0.300 0.350 0.400 Rating__________________________________________________________________________16.sup.22400 1200 -- 17.0 9 8 5 7.317.sup.32325 1200 75 29.5 5 4 4 4.318.sup.32400 1125 75 27.0 5 4 3 419.sup.32250 1200 150 32.6 5 4 3 420.sup.32400 1050 150 37.2 4 3 3 3.3__________________________________________________________________________ .sup.1 These foam samples were prepared when the absolute humidity ranged from 63 to 69 grains of water per pound of dry air. .sup.2 Comparative Experiment. .sup.3 Example of the present invention.
EXAMPLE 5
Various levels of several hindered phenolic antioxidants, 4,4'-bis(α,α-dimethylbenzyl) diphenyl amine and phenothiazine were employed to stabilize either Polyol A or Polyol B. Polyol A was described in Example 1. Polyol B was the reaction product of propylene oxide with a glycerine-propylene oxide reaction product having a molecular weight of about 450, the resultant polyol having a molecular weight of about 3000. The results of the polyol stability determination are presented in Table V. The hindered phenolic antioxidants were abbreviated as follows:
BHT 2,6-ditertiarybutyl-4-methyl phenol
DMOP 2,4-dimethyl-6-octyl phenol
DMTBP 2,4-dimethyl-6-tertiarybutyl phenol
MBMTBP 2,2'-methylene bis(4-methyl-6-tertiarybutyl phenol)
MBETBP 2,2'-methylene bis(4-ethyl-6-tertiarybutyl phenol)
HDTBP 4-hydroxymethyl-2,6-ditertiarybutyl phenol
ODTBHPP n-octadecyl-beta (3,5-ditertiarybutyl-4-hydroxyphenyl) propionate
All other appreviations are the same as defined in Example 1.
TABLE V__________________________________________________________________________SAMPLE PHENOLIC ANTIOXIDANT LEVEL, ppm I.P. TEMP. I.P.NUMBER POLYOL ANTIOXIDANT PHENOLIC DMBDPA PTZ °C. MIN.__________________________________________________________________________21.sup.1 B BHT 250 250 -- 140 19.722.sup.2 B BHT 225 250 25 140 47.723.sup.2 B BHT 250 225 25 140 32.521.sup.1 B BHT 5000 5000 -- 180 19.625.sup.2 B BHT 4500 5000 500 180 38.826.sup.2 B BHT 5000 4500 500 180 35.727.sup.1 A DMOP 2400 1200 -- 170 12.528.sup.2 A DMOP 2325 1200 75 170 16.929.sup.2 A DMOP 2400 1125 75 170 14.830.sup.2 A DMOP 2250 1200 150 170 20.731.sup.2 A DMOP 2400 1050 150 170 18.032.sup.1 B DMTBP 1500 1500 -- 170 10.933.sup.2 B DMTBP 1400 1500 100 170 17.334.sup.2 B DMTBP 1500 1400 100 170 19.435.sup.1 B MBMTBP 1000 1000 -- 170 12.936.sup.2 B MBMTBP 900 1000 100 170 20.137.sup.2 B MBMTBP 1000 900 100 170 20.838.sup.1 B MBETBP 1500 1500 -- 170 14.339.sup.2 B MBETBP 1400 1500 100 170 22.540.sup.2 B MBETBP 1500 1400 100 170 25.241.sup.1 B HDTBP 1500 1500 -- 170 27.242.sup.2 B HDTBP 1400 1500 100 170 38.443.sup.2 B HDTBP 1500 1400 100 170 41.344.sup.1 B ODTBHPP 1500 1500 -- 170 14.645.sup.2 B ODTBHPP 1400 1500 100 170 36.546.sup.2 B ODTBHPP 1500 1400 100 170 36.5__________________________________________________________________________ .sup.1 Comparative Experiment .sup.2 Example of the present invention
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Polyols stabilized against oxidative degradation with a synergistic combination of a sterically hindered phenol and 4,4'-bis(α,α-dimethylbenzyl)diphenyl amine are improved by replacing a portion of either the phenol or the amine or a portion of both with a phenothiazine compound.
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BACKGROUND OF THE INVENTION
1. The invention relates to a process for coring a video signal and particularly to the frequency selective coring of a video signal prior to performing aperture correction.
2. Prior Art
In video processing systems, compromises generally are made when attempting to improve a video detail signal with conventional aperture correction and coring techniques. Coring techniques are used to remove objectionable noise which is emphasized during the aperture correction of the video signal, while optimizing the original shape of the high frequency video detail transitions enhanced by the aperture correction process. Since noise generally increases at the rate of six decibels (db) per octave, the larger quantity of noise exists in the high frequency signal components. Although high frequency noise is not as noticeable to the eye as low frequency noise, the former often is translated when processed, by way of aperture correction, and reappears looking like low frequency noise. The conventional coring techniques core a slice out of the entire signal bandwidth which also removes picture information, particularly at the low frequency end of the spectrum. Typical of such a coring technique is that exemplified in U.S. Pat. No. 3,995,108 to F. Morrison, assigned to the same assignee as this application.
However, use of a coring process after the aperture correction process is, as previously mentioned, a compromise, since it is commonly known that coring the complete detail signal over its entire bandwidth, after aperture correction, generates a loss of low frequency detail information, which is most noticeable during low light levels. Further, the level of coring is compromised since the signal-to-noise ratio when coring after aperture correction is lower than when coring before correction.
SUMMARY OF THE INVENTION
Accordingly, it is an object of the invention to provide a simple coring circuit which provides an improved video detail signal by coring before aperture correction.
Another object of the invention is to provide frequency selective coring of the video signal prior to aperture correction.
A further object of the invention is to core a video signal while retaining the low frequency detail information.
To this end, the video signal is low pass filtered and fed to a summing amplifier. The complimentary high passed video signal is derived from the current return path of the low pass filter and is transformer coupled to a coring means proper. The latter is formed of a pair of transformers intercoupled via a balanced amplifier, which, in effect, provides the coring function by a controlled rectifying action. To this end, the conduction of the balanced amplifier is controlled via coring control voltage fed to a center tap of one transformer secondary. The cored high frequency signal is recombined in the second transformer and is added to the low passed video signal via the summing amplifier to provide the cored composite video signal. The latter is then fed to the aperture corrector circuitry.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic diagram depicting an implementation of the coring circuit of the invention combination.
FIGS. 2A-2E are graphs of waveforms depicting the coring technique of the circuit of FIG. 1 with respect to the video signal bandwidth.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to FIG. 1, a broadband video signal, as generated, for example, via a camera head system, is supplied via input 10 to a current source 12. The latter is formed of a transistor whose base is coupled to the input 10, whose emitter is coupled to a negative voltage via a resistor 14, and whose collector feeds a low pass filter 16. The filter 16 includes a pair of capacitors 18, 20 coupled to respective ends of an inductor 22 and thence to a positive voltage via a resistor 24. The junction of capacitors 18, 20 and resistor 24 defines the current return path for the low pass filter and thus a high pass filter, which is coupled to the emitter of an amplifier transistor 26. The base of the latter is grounded, and the collector is transformer coupled to a coring means 28 and particularly to a primary winding of a transformer 30 thereof. The other side of the primary winding is coupled to a negative voltage.
The secondary winding of transformer 30 is coupled at either end to the bases of a pair of transistors 32, 34 which form a balanced amplifier 36. The center tap of the secondary winding is coupled to the emitter of a biasing transistor 38. The emitter thereof is coupled to a positive voltage via a resistor 40, the collector is coupled to a negative voltage, and the base is coupled to a variable voltage source 42 which comprises a coring control input for determining the voltage supplied by the biasing transistor 38 and thus the degree of conduction of the balanced amplifier 36. The voltage source 42 may be remotely located as in a central control unit of a camera system.
The emitters of the transistors 32, 34 are coupled to ground via resistors 44, 46, and the collectors thereof are connected to opposite ends of the primary winding of a transformer 48. A center tap of the primary winding is coupled to a positive voltage, and the secondary winding is coupled to a positive voltage at one end, and to an emitter of a summing amplifier 50 at the other end.
The low passed signal from the filter 16 also is coupled to the emitter of the summing amplifier 50 via a resistor 52. The base of the latter is grounded, and the collector is coupled to a negative voltage via a resistor 54 and provides the high frequency cored video signal on output 56, which may then be fed to an aperture corrector circuit (not shown).
The bandwidth of the video input signal is depicted in FIG. 2A as extending from zero to ten megaHertz (MHz), by way of example only. The undesirable noise is also depicted and increases with increasing frequency on the order of six decibels (db) per octave. It is this noise that conventional coring techniques purport to remove. However, it may be seen that coring techniques which remove a constant slice of the noise (indicated in exaggerated form by dashed lines and numeral 58) throughout the entire bandwidth, also remove much of the desirable low frequency video detail information during corresponding low light levels as shown in FIG. 2A. Loss of this low frequency detail information results in picture degradation which is readily descernible by the eye.
Thus, the coring technique described herein provides frequency selective coring wherein the noise corresponding to the high frequency components is cored out, while the low frequency detail information is retained.
To this end, the video signal from input 10, depicted by FIG. 2A, is low pass filtered, and the resulting low passed video signal with its attendant noise (FIG. 2B) is fed to the summing amplifier 50 via the resistor 52. The complimentary high passed signal with its attendant noise (FIG. 2C) appears at the common junction of capacitors 18, 20 and resistor 24, and is transformer coupled by amplifier transistor 26 to the coring means 28. By way of example only, a frequency of two megaHertz is herein selected as the upper limit of the low pass filter 16. Thus, the low pass filter 16 provides not only the low frequency component of the video signal, but also the high frequency component thereof. The transformer 30 of the coring means 28 receives the high passed video signal and, along with the balanced amplifier 36, provides, in effect, a full wave rectifying action which removes a portion of the high frequency component about its neutral point. That is, the balanced amplifier performs as a class B amplifier. The extent of the rectifying action, i.e., the conduction angle of the balanced amplifier 36, is controlled by the biasing voltage applied to the center tap of the transformer 30 secondary via the biasing transistor 38 and the variable voltage source 42. In effect, the biasing voltage determines the conduction angle and thus the type of operation of the balanced amplifier 36, i.e., class A, AB or B which, in turn, determines the extent of coring performed on the high passed video signal. Further, the variable voltage source 38 provides temperature compensation for the balanced amplifier 36.
The cored signal is then recombined by transformer 48, depicted in FIG. 2D, and is fed to the summing amplifier 50. The low passed signal from the filter 16 (FIG. 2B) is added to the cored high passed signal of FIG. 2D to provide the resultant composite video signal minus the high frequency noise on output terminal 56. As shown in FIG. 2E, the cored composite video signal retains only a small amount of noise in the low frequency component of the signal, whereby low frequency detail information is retained while noise in the high frequency portion is removed.
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A coring circuit located prior to the aperture corrector circuit provides fast acting, remotely controlled, temperature compensated, frequency selective coring of the video signal. The wideband video signal is separated into its low frequency and high frequency components. The high frequency component is transformer coupled to a coring means proper which cores out the corresponding high frequency noise. The cored high frequency component then is recombined with the low frequency component to reconstitute the cored composite video signal for subsequent application to the aperture correction circuit.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is filed under 35 U.S.C. §111(a) and §365(c) as a continuation of International Patent Application No. PCT/IB2013/061225, filed Dec. 20, 2013, which application claims priority from German Patent Application No. 10 2013 100 084.3, filed Jan. 7, 2013, which applications are incorporated herein by reference in their entirety.
FIELD OF THE INVENTION
[0002] The present invention concerns a procedure for the manufacture of at least one layer for solid state thin-film batteries by plasma powder spraying. Furthermore, the present invention concerns a plasma-powder-sprayer for the manufacture of at least one layer for solid state batteries onto a substrate. The plasma-powder-sprayer comprises a plasma generation area, in which a plasma gas stream can be generated with the help of an energy source, and at least one mixing area that is located in the plasma gas stream. The present invention also includes a solid state battery manufactured by a procedure in accordance with the invention.
BACKGROUND OF THE INVENTION
[0003] Solid state batteries, in a multitude of applications, can satisfy the requirements for high-performance, cheap, safe, primary and secondary batteries that can be integrated in existing products. They distinguish themselves by high cycle stability, low self-discharge, safety and low toxicity. Increasing miniaturization requires even smaller batteries with more flexible architecture and at the same time higher volumetric or specific power density. Solid state batteries can, for instance, be used in autonomous microsystems such as microelectromechanical systems (MEMS), electronic parts through RFID tags, various wireless sensors, smart credit cards, portable electrical devices, functionalized apparel and even electro mobility applications.
[0004] A typical solid state thin-film battery stores energy chemically, preferably in low-order alkali metals such as lithium or sodium. The energy stored chemically in, for instance lithium (Li), can be utilized as electrical energy through an exothermic oxidation to a Li + -anion:
[0000] Li⇄Li + +e −
[0005] A solid state thin-film battery consists of a cathode and an anode that are physically separated by an electrolyte. During the charging or discharging a solid state thin-film battery, there are always two opposing currents flowing against each other, one current of ions and an electrical compensating current for the charge balance. The electrical power emanating from this compensating current and the battery voltage can be used by a consumer. The electrolyte is conducting with respect to the ion current and insulating with respect to the current of electrons. As a result, an electron current can flow only if the anode and the cathode are electrically connected. If no electron current can flow, the ion current coulomb is suppressed, so that the energy remains chemically stored.
[0006] During the discharge process, the Li in the anode is oxidized to Li + . If there is an electrochemical potential difference from the anode to the cathode, the ions diffuse into the cathode. During the charging process, the process runs in the opposite direction. The ions that diffuse into the cathode are intercalated in the cathode material during the charging process and accordingly de-intercalated during the discharging process. A suitable intercalating material consists, for instance, of crystalline layers of an oxide of transition metals like lithated cobalt dioxide (LiCoO 2 ).
[0007] The following reactions take place in a LiCoO 2 cathode during the charging and discharging processes, whereby the roman figures indicate the level of oxidation:
[0000] Li +I Co +III O 2 −II ⇄Li 1-x +I Co 1-x +III Co x −II +x Li +I +xe −I ,
[0008] To increase the volumetric or specific storage capacity (measured as Wh/ccm or Wh/g), the volume of the cathode layer can be increased. Since the projected basic surface area of the thin-film battery is usually specified by its application, the cathode volume per layer system consisting of cathode, electrolyte and anode can be increased only through the thickness of the film. On the other hand, the electrical and ion conductivity of the layer system reduces with increasing thickness of the cathode layer. The cathode layer and also the electrolyte layer must therefore be made as thin as possible and also free of defective spots. The thinner the layer thickness and the larger the interface between cathode and electrolyte as well as between the electrolyte and the anode, the better is the ion conductivity of the layer system.
[0009] Carrying out all the production stages of a thin-film battery on a continuously running production band during the automated series production is recommended. Consequently, the slowest sub-process determines the cycle time of the production. Production costs correlate directly with the production cycle time. The coating process of the cathode is often a restricting factor for the production cycle time.
[0010] One requirement for rechargeable secondary batteries is that the ability for intercalation of the cathode material is retained over many intercalation and de-intercalation cycles and that it withstands the mechanical stress in conjunction with it. The electrochemical properties of a cathode layer are mainly determined by their crystalline structure, chemical stoichiometry, morphology, such as crystallinity, particle size distribution and the porosity of the layer.
[0011] In U.S. Pat. No. 5,612,152, a rechargeable solid state multi-cell battery has been revealed. The individual cells consist of a cathode layer made of a lithium intercalation material, an electrolyte layer of lithium-phosphorus-oxynitride (LIPON) and an anode layer of lithium. Batteries with different battery amperages, voltages and capacities can be manufactured by structuring and connecting several cells in series or parallel. The energy content of the battery can also be raised by the thickness of the cathode and anode layers.
[0012] U.S. Pat. No. 5,445,906 describes a method and a system for the manufacture of a thin-film battery. A net-like substrate is automatically passed through a multitude of coating stations. In the coating stations, the layers are successively coated on the substrate in a layer sequence typical for solid state thin-film batteries. Masks can be used for structuring the layers. In particular, the battery coated net-substrate can be rolled up. Preferably, the net-substrate is arranged on a conveyor belt. To ensure that the conveyor belt can move continuously during the coating process, the length of the individual coating stations is matched to the relevant layer.
[0013] In German patent specification DE 100 53 733 B4, a procedure for crystallization of a thin-film from a lithium-transition metal oxide has been suggested. In the first step, a thin-film of a lithium-transition metal oxide is vapor-deposited on a substrate, e.g., with the help of a HF-magnetron sputter source. In the subsequent step, the thin-film is post-treated with an oxygen or inert gas plasma to increase the degree of crystallization, the surface smoothness and electrochemical resistivity of the thin-film material.
[0014] The translation DE 601 26 779 T2 of the patent specification EP 1 305 838 B1 describes a thin-film energy storage device on a substrate with a melting, or decomposition temperature under 300° C. as well as a procedure for its manufacture. Different materials such as LIPON or lithium intercalation materials from one or more DC-magnetron sputter sources can be deposited on the substrate. Likewise, one or more auxiliary sources can be directed onto the substrate and the material layer can be impinged with force with energized auxiliary materials so that the crystal growth with regard to crystallite size and crystal orientation can be controlled.
[0015] French patent application FR 2 729 400 reveals a plasma supported process for depositing a thin metal oxide layer, the material so obtained and a battery with this material. To improve the porosity and composition of the deposited material as well as its adhesion on a substrate, a metal is injected not as a powder but as an aqueous solution in a plasma generator. The metal particles oxidize due to high oxygen content in the plasma.
[0016] International patent application WO 2009/033522 A1 reveals a procedure and a device for the treatment or coating of surfaces with a plasma jet. The plasma jet is created in one or more plasma generators and injected into one or more reaction chambers connected to the plasma generator and thoroughly mixed with an aerosol. The plasma activated aerosol is deposited onto a substrate. To avoid damaging the substrate by undesired plasma induced physical or chemical processes, the plasma jet is injected into the reaction chamber in such a way that no plasma comes out of the reaction chamber and thus the direct contact of plasma with the substrate is avoided.
[0017] In the patent application U.S. 2011/0045206 A1, a procedure and a device for the manufacture of an electrochemical layer of a thin-film battery is revealed. A dispenser is arranged in a process chamber. Plasma is ignited from a precursor mixture in an activation chamber of the dispenser. The precursor mixture consists of a solution, suspension or slurry of precursor particles in a fluid carrier medium. The precursor mixture can contain in particular, cobalt, nickel, magnesium, their nitrates or lithium. The plasmafied precursor mixture is mixed in a mixing area with oxygen and a combustible gas that adds additional thermal energy to the precursor particles. The precursor mixture and oxygen react in a reaction chamber to form electrochemically active nanocrystals that are deposited on a substrate. In particular, the admixture of a carbonaceous gas is intended for wrapping the nanocrystals with carbon. Furthermore, a polymer binding agent is fed to the gas stream which contains the nanocrystals so as to create a layer of nanocrystals and polymer binding agent.
[0018] A disadvantage of the state-of-the-art is the typically restricted rate of deposition. Methods such as physical vapor phase deposition (PVD), thermal vapor deposition or sputtering deliver deposition rates of just a few nm/s and require sophisticated vacuum units with a basal pressure under 10 −4 mbar or preferably even under <10 −6 mbar. In particular, the cathode material is manufactured by chemical reaction first in the manufacturing process or taken from a solid target. Such deposition techniques restrict the speed of the process or are unsafe with respect to the achieved layer stoichiometry and morphology. Especially, in the case of stacked batteries, the insufficient reproducibility of the layer properties is a disadvantage and increases production rejects.
BRIEF SUMMARY OF THE INVENTION
[0019] The primary object of the present invention is to create a procedure for the manufacture of thinner and mechanically more stable layers for solid state thin-film batteries that can be integrated into a production process quickly, cost-effectively, simply, reliably, flexibly and one that is capable of automation.
[0020] Another object of the present invention is to create a plasma-powder-sprayer for manufacturing thinner layers for solid state thin-film batteries, with which one can manufacture the layers for a solid state thin-film battery quickly, cost-effectively, reliably and in a procedure that can be automated.
[0021] Likewise it is an object of the present invention to create a long-term high-performance solid state thin-film battery that is, mechanically stable and simple and cost effective to manufacture.
[0022] Another object of the present invention serves the manufacture of at least one layer for solid state thin-film batteries or super condensers. Layer types that can be manufactured according to the present invention can include the current collectors, the anode, the cathode, the electrolyte, the electronic separator or a protective outer coating. Several of the layers of the same type of layer can be manufactured in thin-film batteries in accordance with the present invention. The layers manufactured in accordance with the present invention comprises powder particles that have been prepared or electrochemically activated with the help of a plasma-powder-sprayer and deposited on a substrate. The plasma-powder-sprayer comprises a plasma generation area and at least one mixing area spatially separated from it.
[0023] At first an ignition gas is fed into the plasma generation area. A plasma gas stream is created out of the ignition gas stream by bombarding with energy. In accordance with the present invention, the ignition gas stream consists of gaseous raw materials, however not liquid or solid raw materials.
[0024] Furthermore, a powder-aerosol stream is created. A powder-aerosol in accordance with the present invention comprises exclusively powder particles of solid aggregate status dispersed in a carrier gas. The powder-aerosol stream can be created in a preferred manner in which carrier gas from a carrier gas reservoir streams into a power reservoir and carries along powder particles contained in it. The powder-aerosol stream is taken from the powder reservoir, for example over a powder-aerosol supply line that is under low pressure relative to it, and fed to at least one of the mixing areas. Furthermore, the plasma stream from the plasma generation area is fed into this mixing area. Due to that, the plasma gas stream and the powder-aerosol stream mix with each other, so that a plasma-powder-aerosol is created.
[0025] The plasma-powder-aerosol is channeled out in a stream from at least one mixing area and directed at a substrate that is arranged in a coating area. The powder particles dispersed in the plasma-powder-aerosol stream are deposited as a layer on the substrate in the coating area. The powder particles are modified under the effect of the plasma.
[0026] In particular, powder particles can be withdrawn in precise doses under the admixing of carrier gas in such a manner, that a constant mass flow of powder particles dM/dt and a constant mix ratio of powder particles and carrier gas is set, where M is the mass of powder particles transported in the powder-aerosol stream and t is the time. The powder-aerosol stream is kept constant, at least over a withdrawal period that lies within the typical time scale of the coating process. Alternatively, any target mass flow profiles dM/dt(t) and/or mixing ratios between carrier gas and powder particles in the powder-aerosol stream across the extraction time period can be adjusted in a controlled manner.
[0027] Furthermore, the method can channel the powder-aerosol stream through a device that brings it to a temperature required for running the process. The substrate may also be heated by a substrate heater.
[0028] The method of the present invention can also utilize an adjusting system to move the plasma-powder-sprayer and/or the substrate or the substrate holder. Such a relative movement so effected between plasma-powder-sprayer and substrate can take place in one or all three spatial dimensions and include tilting relative to one or both spatial angles. In this way, the plasma-powder-sprayer can track over and coat the surface of substrates of any two or three dimensional topography along any trajectory. Also, the angle of incidence of the plasma-powder-aerosol stream relative to the surface can be set so as to extensively coat, for instance, depressions in the substrate. In particular, the distance between the plasma-powder-sprayer and the substrate can be set. This distance is determined by the softening of the plasma-powder-aerosol stream, the size of the coating area, the heat flow per unit area carried by it to the substrate per unit area and the rate of coating or a gradient of the rate of coating over the coating area.
[0029] For example, a flat substrate can coat the whole or part of the area along a meandering or spiral trajectory by a relative movement of the plasma-powder-sprayer. By adjusting the trajectories and/or by interruption of the supply of power particles, layers of any shape can also be coated. In addition, a static or structural element that can likewise be adjusted by an adjusting system can be introduced into the plasma-powder-aerosol stream on or over the substrate, so as to structure the deposited layer. The structuring element can be a screen over, or a mask on, the substrate or can be created by lithographic methods.
[0030] The method of the present invention can also be carried out in a coating chamber in which the substrate has been introduced. For this, the plasma-powder-sprayer can be arranged inside or outside the coating chamber and can be connected to it in a fluid manner. This way the coating process can be carried out under an inert gas atmosphere. In particular, a negative pressure can be created in the coating chamber with the help of a suction pump so that the coating takes place under low pressure or vacuum conditions.
[0031] In another object of the method of the present invention, one auxiliary material each can be introduced in at least one mixing area. An auxiliary material and/or a powder-aerosol stream can be introduced in at least one more mixing area. Thus, different mixing areas can be fed with different materials. At least one more mixing area lies in the plasma-powder-aerosol stream and can lie inside or outside the plasma-powder-sprayer. The auxiliary material can, for example, be a carbonaceous gas for plasma supported vapor deposition of carbon or other powder-aerosol whose powder particles have a different chemical, electrochemical or structural composition than the powder particles introduced into the first mixing area. The powder particles introduced into the first mixing area can be partly or wholly coated or fully wrapped up with one or several auxiliary materials. The process conditions in the mixing areas can, for example, be set by the plasma properties, the temperature and/or the pressure or partial pressure conditions.
[0032] For the manufacture of an anode or cathode layer of a solid state thin-film battery, the powder particles, in accordance with the present invention, consist of an intercalation material suitable for the embedding of ions. Preferably, the solid state thin-film battery is based on the intercalation of alkali metals such as lithium ions. The powder particles consist, e.g., of a lithated oxide of one or several transition metals.
[0033] According to another method of the present invention, the powder particles from which the layer will be built up are thermally activated in the plasma-powder-aerosol stream. Furthermore, the powder particles in the plasma-powder-aerosol are not altered with respect to their chemical stoichiometry and their particle size distribution. Due to the particle size distribution the particle stream contains solid and melted portions that solidify abruptly on hitting the substrate and thus create a firm bond. The porosity of the layer is essentially determined by the particle size distribution of the particles as well as its temperature and pressure dependent diffusibility on the substrate. The diffusibility can be set, e.g., by the rate of deposition, the substrate temperature or the impact velocity of the powder particles on the substrate. The higher the substrate temperature or the impact velocity and the lower the rate of deposition, the more time remains for the rearrangement of the powder particles on the substrate and the more dense the layer tends to be. The porosity of the layer can reduce the mechanical stress that occurs for instance during the intercalation and de-intercalation cycles of ions in a cathode layer. Furthermore, it can increase the ion conductivity of the battery by increasing the effective surface area.
[0034] The ignition gas stream and/or the carrier gas stream consists preferably under process conditions of one or more chemically inert gases such as argon or nitrogen. Additionally, partial streams of oxygen, hydrogen and/or a carbonaceous gas metered through flow controllers can be admixed. Hydrogen can, for example, function as a reduction agent. In accordance with the present invention, the plasma-powder-aerosol stream is additionally heated by the controlled oxidation of combustible gases such as hydrogen or the carbonaceous gases. In a typical forming gas consisting of nitrogen and hydrogen in accordance with the present invention, the hydrogen portion usually lays less than 10 weight percent of the total gas stream, preferably however between 3 and 7 weight percent. Correspondingly, the flow rates of, e.g., nitrogen and hydrogen, each lie in the range of 10-25 sccm. Typically the set total pressure, at least in one mixing area, lays around 0.5-2.5 bar.
[0035] In another object of the present invention, the powder particles can be thermally activated with respect to their electrochemical properties. For that the temperature in the plasma-powder-aerosol stream is set for instance by modulation of the coupled energy in the plasma generation area, the total pressure and the ratios of the partial pressures of the gases contained therein. Furthermore, the temperature can be influenced by the substrate heater or the device for the temperature control of the plasma-power-aerosol. In accordance with the present invention, different temperatures and partial pressures can thus be set in different mixing areas. At the same time, the chemical stoichiometry or the chemical stoichiometric ratio of oxidic powder particles such as Li x CoO 2 by admixing of oxygen, can be obtained in an atmosphere with excess oxygen. Oxygenic defects in Li x CoO 2 -powder particles reduce the ion conductivity and ability for intercalation of lithium ions and as a result the battery power.
[0036] In an embodiment of the method of the present invention, the powder particles of lithium cobalt dioxide are thermally altered in the HT-phase. Additionally a mixing temperature in the region of 350° C. to 750° C. is set in at least one mixing area. For setting the mean heat input per powder particle and the chemical stoichiometry of the powder particles, the total pressure as well as the partial pressures are matched to the mixing temperature. The ratio of mixing temperature to the partial pressure of oxygen is particularly essential for achieving a high portion of defect-free lithium cobalt dioxide in the HT-phase. At the same time, the substrate temperature is maintained under 240° C., for instance at 200° C.
[0037] The present invention further includes a plasma-powder-sprayer for the manufacture of at least one layer on the substrate for solid state thin-film batteries. It includes a plasma generation area and an energy source for generation of a plasma stream as well as at least one mixing area that lies within the plasma gas stream. In accordance with the present invention, the plasma generation area is thus spatially separated from at least one mixing area. In particular, with the plasma-powder-sprayer in accordance with the present invention, only one ignition gas stream can be introduced into the plasma generation area. Consequently, plasma is exclusively ignited from the ignition gas stream. The plasma gas stream thus obtained flows from the plasma generation area to at least one mixing area. One powder-aerosol stream can be introduced through at least one powder-aerosol supply line to at least one mixing area. The plasma gas stream and the powder-aerosol stream mix with each other to a plasma-powder-aerosol stream in at least one mixing area. Particularly, no powder-aerosol enters the plasma generation area. Thus abrasive or conductive powders can also be processed in the plasma-powder-sprayer without soiling, damaging or electrically short-circuiting it.
[0038] In an embodiment of the present invention, at least one powder-aerosol supply line can be assigned one device for setting a temperature of the powder-aerosol stream. Similarly, the substrate can be arranged opposite the plasma-powder-sprayer on a substrate holder with a substrate heater for setting the substrate temperature.
[0039] Furthermore, the plasma-powder-sprayer can be assigned an adjustment system for generation a relative movement between the plasma-powder-sprayer and the substrate holder.
[0040] In a preferred embodiment of the present invention, at least one mixing area includes a first mixing area and at least a second mixing area that are arranged spatially separated from each other and within the plasma-powder-sprayer. Additionally, at least one second mixing area can include at least another mixing area that is arranged outside the plasma-powder-sprayer. Furthermore, an auxiliary material can be introduced into each mixing area through the at least one powder-aerosol supply line.
[0041] The present invention further includes a solid state thin-film battery in which at least one layer is manufactured from powder particles by a novel process. Particularly, in accordance with the present invention, mechanically stable and electrochemically active layers with respect to their electrochemical properties can be manufactured from activated powder particles and without using additives, e.g., binding agents. Similarly, one can do away with auxiliary materials that are potential contaminants for the layers.
[0042] The cathode layer can, for example, consist of Li x CoO 2 , LiNi x Co 1-x-y Mn y 0 2 , Li x FePO 4 , Li x Mn 2 O 4 , Li x NiO 2 , Li x NiCoO 2 , Li 2 FeSiO 4 , Li 2 MnSiO 4 , or Li 2 VOSiO 4 , TiS 2 , TiOS or Na 5 V 2 (PO 4 ) 2 F 3 . The method of the present invention is preferably run in such a way that the lithium content x of the lithium embedded in the intercalation material does not fall below the stability range. If the lithium content falls below the stability range, the intercalation ability of the intercalation material is irreversibly reduced and as a consequence of this also the capacitance of the thin-film battery. In case of Li x CoO 2 the stability range lies, e.g., at 0.5<x=<1. Furthermore, powder particles with a special electrochemically advantageous crystalline structure can be used. For instance, powder particles in the powder reservoir of Li x CoO 2 -crystallites can exist in the HT-phase. On the basis of its rhombohedral structure, HT-Li x CoO 2 has a particularly favorable intercalation kinetic for the conduction and storage of lithium ions. A particular advantage of the procedure is that the powder particles with regard to their particle size distribution can be pre-selected and checked for quality and if need be reselected before they are essentially deposited as a layer without change in particle size distribution or stoichiometry. In this way the production rejection can be reduced.
[0043] The anode layers in accordance with the present invention can consist of the same material as the cathode layers or can consist of pure lithium. Cathode and/or anode layers can further include a matrix. A matrix such as this can stabilize the anode layer that is stressed by intercalation cycles or increase its electrical and/or ion conductivity. The matrix can for example consist of polymers, graphite, buckyballs, carbon nanotubes, lithium titanate, silicon and/or tin.
[0044] The electrolyte layer can consist of amorphous lithium phosphorous oxide nitride (Li x PO y N 2 or “LIPON”). It can be manufactured by a procedure in accordance with the present invention directly from LIPON powder particles. Alternatively, the electrode material can be synthesized by a reaction of, e.g., or from, e.g., lithium phosphate in a nitrogenous plasma gas stream. The use of a material such as LIPON that is conducting with respect to lithium ions and insulating with respect to electrons, makes an additional separator layer for electrical separation of cathode and anode unnecessary.
[0045] Furthermore, the cathode and anode layers of the thin-film battery can include current collectors. They can consist, e.g., of aluminum, copper, silver, nickel, nanowires, carbon nanotubes, graphite or conductive polymers. The cathode or anode layer can even themselves be designed as current collectors.
[0046] Due to the lower substrate temperature of 240° C. to under 90° C. when compared to other procedures, combined with mechanical stability and bonding strength of the deposited layers, the procedure in accordance with the present invention is suitable for a multitude of substrate materials such as stainless steel foils, mica, semiconductor wafers, glasses, polymer films textiles or paper. Furthermore, thin-film batteries in accordance with the present invention can be directly structured onto electronic printed circuit boards (PCB) or micromechanical system/(MEMS)-building blocks and can be electrically connected with these directly at the switching level. The procedure is also suitable for the manufacture of flexible thin-film batteries on flexible substrates.
[0047] The typical layer thicknesses of a thin-film battery in accordance with the present invention are between 1 μm and 500 μm for anode layers, typically however 10 μm to 100 μm, 0.1 μm to 10 μm for electrolyte layers, typically however 1 μm, and between 0.5 μm and 100 μm for current collectors, typically however 50 μm.
[0048] A particular advantage of the method of the present invention is its high rate of deposition when compared to state-of-the-art. Typical rates of deposition lie between 3 and 5 g/min or even 2-10 g/min. In relation to the layer thickness, typical rates of coating from 100 μm/s to a few 100 μm/s can be achieved. The feed rate of the relative motion between plasma-powder-sprayer and substrate for the deposition process is, e.g., 100 to 200 mm/s, at a gap in the range of 3-15 mm.
[0049] In another object of the present invention jets, or jets that can be dosed can be formed on the opening of the plasma-powder-sprayer, at the ignition gas inlet, between the plasma generation area and a mixing area and/or at the junctions of the powder-aerosol supply lines in a mixing area.
BRIEF DESCRIPTION OF THE DRAWINGS
[0050] In the following paragraphs, embodiments of the procedure in accordance with the present invention and the device for the manufacture of at least one layer for solid state thin-film batteries in described in detail with the help of the attached drawings. These exemplarily concretized embodiments are not to be considered as limitations for the scope of the invention.
[0051] The invention is described in detail below with reference to the drawings, wherein:
[0052] FIG. 1 shows a schematic sectional view of a layer system of a solid state thin-film battery;
[0053] FIG. 2 shows a sectional view through an embodiment of a solid state thin-film battery with structured layer build-up;
[0054] FIG. 3 shows a schematic depiction of a procedure in accordance with the present invention for the manufacture of a layer for solid state thin-film batteries with the help of a plasma-powder-sprayer;
[0055] FIG. 4 shows a schematic sectional view of another embodiment of the plasma-powder-sprayer in accordance with the present invention;
[0056] FIG. 5 shows a schematic sectional view of another embodiment of the plasma-powder-sprayer in accordance with the present invention; and,
[0057] FIG. 6 shows a schematic sectional view of yet another embodiment of the plasma-powder-sprayer in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
[0058] Identical reference numbers in the drawings refer to similar or identical structural elements of the invention. FIG. 1 shows the principal structure of a solid state thin-film battery 100 built up layer by layer as per the state-of-the-art. On a substrate 33 , one cathode layer 102 followed by one electrolyte layer 103 and an anode layer 104 are deposited. The electrolyte layer is an ion conductor, so an ion current can flow between cathode layer 102 and anode layer 104 . During the charging process of the solid state thin-film battery 100 , the ion current causes an intercalation of ions in the cathode layer 102 and correspondingly their de-intercalation from the anode layer 104 or vice versa for the discharging process. At the same time, the electrolyte layer 103 is an insulator in relation to the conduction of electrons, so that it electrically separates the anode layer 102 and the cathode layer 104 . An ion current is electrostatically suppressed if the anode layer 102 and the cathode layer 104 are electrically connected otherwise, so that an electric compensation current can flow for charge balancing. The electric power resulting from this compensation current and the battery voltage can be utilized by a consumer. For a preferably loss free absorption of this power, the anode layer 102 and cathode layer 104 can each be coated by an electrically conductive current collector 33 and 105 with low electrical boundary surface resistance. In FIG. 1 , the substrate 33 itself functions as the current collector of the cathode layer 104 .
[0059] The capacity of the solid state thin-film battery 100 can be increased in accordance with the present invention by increasing the volume of the cathode layer 102 with a larger layer thickness D. Technically, the layer thickness D is limited however by the mechanical stress, which accompanies the volume change of the intercalation material during intercalation and de-intercalation. Stability and lifespan of the solid state thin-film battery 100 can be increased by reducing the mechanical stress with a porous design of the cathode layer 102 . For increasing the compensation current or the battery voltage, at least the ion conducting layer sequence 110 can be connected in parallel and/or in series.
[0060] FIG. 2 shows a schematic sectional view through another embodiment of a solid state thin-film battery 100 with structured layer build-up. In this embodiment, a current collector 101 is provided on an electrically insulating substrate 33 . The previously described layers 102 , 103 and 104 , with reference to FIG. 1 , are covered over their whole surface by an electrically insulating protective layer 106 . For the purposes of contacting, the surfaces of the collectors 101 and 105 are partly free. FIG. 2 shows that any two or three dimensional structured layers 32 of solid state thin-film batteries 100 can be manufactured by the procedure in accordance with the present invention. Likewise, substrates 33 with any three dimensional topography can be coated.
[0061] FIG. 3 shows a schematic depiction of a procedure in accordance with the present invention for the manufacture of at least one layer 32 for solid state thin-film batteries 100 with the help of a plasma-powder-sprayer 1 . An ignition gas stream 12 is introduced into a plasma generation area 10 and bombarded with energy 11 so that a plasma gas stream 13 is ignited from the ignition gas stream 12 . The plasma gas stream 13 flows into a mixing area 20 that is spatially separated from the plasma generation area 10 . Furthermore, in a powder dosage unit 40 a powder-aerosol stream 44 is created from a powder 23 and a carrier gas 42 and dosed into the plasma gas stream 13 in the mixing area 20 . Due to this, a plasma-powder-aerosol stream 34 is created, which is directed from the mixing area 20 onto a substrate 33 arranged in a coating area 30 . Therefore a layer 32 of powder particles that can be modified in the plasma-powder-aerosol stream 34 is deposited on the substrate 33 . During plasma ignition, high ignition temperatures T 10 of up to 10,000 K can occur in the plasma generation area 10 . As the mixing area 20 is spatially separated from the plasma generation area 10 , a considerably lower mixing temperature T 20 of under 1,000° C. can independently be set there. Analogous to this, a substrate temperature T 33 can also be independently set. To prevent powder particles from entering the plasma generation area 10 , a higher ignition pressure P 10 than the mixing pressure P 20 in the mixing area 20 can be set there. To ensure that the streams flow as described earlier, the mixing pressure P 20 must be set lower or higher than the dosing pressure P 40 in the powder dosing unit 40 or the coating pressure P 30 in the coating area 30 . P 10 , P 20 , P 30 and P 40 are to be understood as static and/or dynamic pressures. The coated substrate 33 can be sintered, tempered or treated with plasma in a following step.
[0062] FIG. 4 shows a schematic sectional view of an embodiment of a plasma-powder-sprayer 1 in accordance with the present invention, for the manufacture of at least one layer 32 on a substrate 33 for solid state thin-film batteries 100 and a substrate holder 39 , both of which are arranged in a coating chamber 31 . A negative pressure ΔP in relation to the mixing area 20 located in the plasma-powder-sprayer 1 can be created in the coating chamber 31 by a suction pump 60 .
[0063] An ignition gas stream 13 is let into a plasma generation area 10 through an ignition gas inlet 18 . From this a plasma gas stream 13 can be ignited by bombarding with energy 12 from an energy source 15 . The energy source can, e.g., be an electrical voltage source. The electrical voltage source can be created by, e.g., a continuous or pulsed direct and/or alternating voltage on an active electrode 16 against the potential of the plasma-powder-sprayer 1 , the substrate 33 and/or the coating chamber 31 .
[0064] The plasma gas stream 13 flows from the plasma generation area 10 into a mixing area 20 spatially separated from it. At least one powder-aerosol supply line 47 is assigned for the mixing area 20 through which a powder-aerosol stream 44 can be introduced. The plasma gas stream 13 and the powder-aerosol stream 44 mix with each other in the mixing area to a plasma-powder-aerosol stream 34 that can be directed through an opening 28 of the plasma-powder-sprayer 1 onto a substrate so that the powder particles contained in it are deposited as a layer 32 .
[0065] In this way the powder particles can be thermally modified at least in their physical quality. For example, the powder particles can be superficially fused or altered in their crystalline structure. To apply the temperatures and heat flows required for the modification of the powder particles during the residence time in the plasma-powder-aerosol 34 , a combination of pressure or the partial pressure ratio and temperature in the plasma-powder-aerosol 34 can be adjusted. The heat flow is largely fed and regulated by the energy source 15 . Pressure conditions are regulated by mass flow controllers u 0 , . . . , un or v 0 , . . . , vk of the gas components of the ignition gas stream 12 or carrier gas stream 42 . The gas components are held in the respective gas reservoirs 12 l , . . . , 12 n or 42 l , . . . , 42 k . Jets for regulation of pressure and flow can additionally be designed in the ignition gas inlet 18 , in the powder-aerosol supply lines 47 and/or in the opening 28 . The heat input in the powder particles also depends on the geometry of the plasma-powder-sprayer 1 , on the negative pressure ΔP and on the distance 38 from the plasma-powder-sprayer 1 and substrate 33 . Additionally, the temperature of the powder-aerosol stream 44 can be set by a device 46 assigned to the powder-aerosol supply line 47 . Furthermore, a substrate holder 39 can include a substrate heater 36 . To increase the temperature, a gas mixture such as O 2 and H 2 in the plasma-powder-sprayer 1 can also be brought to a controlled exothermic reaction. To limit the in situ temperature in the plasma-powder-aerosol stream 34 , a gas or gas mixture that reacts endothermally above a specific threshold temperature can be introduced. In accordance with the present invention, the introduction of liquids in the plasma-powder-sprayer 1 is avoided so that no thermal energy is lost due to evaporation. Furthermore, the substrate temperature T 33 of the gas or plasma stream directed on the substrate 33 can be influenced by irradiation of light.
[0066] Furthermore, an adjusting system 50 can create a relative movement between the plasma-powder-sprayer 1 and the substrate holder 33 . For instance, the substrate holder 39 can be arranged on a conveyor belt 50 or on a rotating device 50 . The plasma-powder-sprayer 1 and/or substrate holder 33 can also be connected rigidly with an adjusting device 50 that can carry out any translation or rotation along or at least around the x-axis, y-axis and/or the z-axis. Due to the relative movement, structured layers 32 with three dimensional topographies can also be deposited on substrates 33 . Additionally, a structuring element 37 can be introduced into the plasma-powder-aerosol stream 34 , so as to partially shade out or cover the substrate 33 . The structuring element 37 can be designed rigid or adjustable by the adjusting system 51 .
[0067] FIG. 5 and FIG. 6 show schematic sectional views of other embodiments of the plasma-powder-sprayer 1 in accordance with the present invention. In the plasma-powder-sprayer 1 depicted in FIG. 5 , at least the one mixing area 20 includes a first mixing area 20 A and at least a second mixing area 20 B, which are spatially separated from each other and are arranged inside the plasma-powder-sprayer 1 .
[0068] In the plasma-powder-sprayer 1 depicted in FIG. 6 , at least the one mixing area 20 includes at least a first mixing area 20 A and at least a second mixing area 20 B, which are spatially separated from each other, whereby at least one more mixing area 20 C of the at least a second mixing area 20 B are arranged outside the plasma-powder-sprayer 1 . Auxiliary material 44 A, 44 B, 44 C can be introduced into the mixing areas 20 , 20 A, 20 B, 20 C through at least one powder-aerosol supply line 47 , 47 B, and 47 C respectively.
LIST OF REFERENCE NUMERALS
[0000]
1 Plasma-Powder-Sprayer
10 Plasma Generation area
11 Energy
12 Ignition gas stream
12 l first gas reservoir
12 n n-th gas reservoir
13 Plasma stream
14 Ignition gas reservoir
15 Energy source
16 Electrode
18 Ignition gas inlets
20 Mixing area
24 Plasma-Powder-Aerosol
28 Opening
30 Coating area
31 Coating chamber
32 Layer
33 Substrate
34 Plasma-Powder-Aerosol stream
36 Substrate heater
37 Mask
38 Distance
39 Substrate holder
40 Powder dosing unit
41 Carrier gas stream
42 Carrier gas stream
42 l First carrier gas reservoir
42 k k-th Carrier gas reservoir
43 Powder reservoir
44 Powder-Aerosol stream
46 Device
47 Powder-Aerosol supply line
48 Powder particles
49 Plasma-Powder supply line
50 Adjusting system
60 Suction pump
70 Control unit
71 Mass flow control
100 Solid state thin-film battery
101 Current collector
102 Cathode layer
103 Electrolyte layer
104 Anode layer
105 Current collector
110 Layer sequence
P 10 Ignition pressure
P 20 Mixing pressure
P 30 Coating pressure
P 40 Dosing pressure
T 10 Ignition temperature
T 20 Mixing temperature
T 33 Substrate temperature
D Layer thickness
v Ignition gas dosing systems
v 0 Mass flow regulator
v 1 First mass flow regulator
vk k-th Mass flow regulator
u Carrier gas dosing system
uo Mass flow regulator
ul First mass flow regulator
un n-th Mass flow regulator
x x-axis
y y-axis
z z-axis
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A method for the manufacture of a layer for solid state thin-film batteries using a plasma-powder-sprayer with a plasma generation area and a mixing area spatially separated from it, including creation of a plasma gas stream from an ignition gas stream in the plasma generation area; creation of a powder-aerosol stream from a carrier gas stream from a carrier gas reservoir and powder particles from a powder reservoir, wherein the powder particles are extracted in a particular way; introduction of the powder-aerosol stream and the plasma gas stream into the mixing area, so that a plasma-powder-aerosol is formed; directing a plasma-powder-aerosol stream from the mixing area onto a substrate arranged in a coating area; and, deposition of a layer on a substrate of powder particles that are superficially fused or changed in their crystalline structure in the mixing area and/or in the plasma-powder-aerosol stream and/or in the coating area.
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BACKGROUND OF THE INVENTION
The present invention relates to washing machine and move particularly to a washing machine having punch-washing function to reduce the damage of washing article caused by mutual rubbing between the washing article and the pulsator of the washer during washing cycle, and to prevent the wash articles from being entangled with each other, by using up-and-down water flow or non-symmetrical heart-shaped water flow which is generated by the rotation of the pulsator so as to improve the washing effect.
Up to now, many attempts have been made to change the shapes and structures of the pulsator of the washing machines in various forms, for example, bar type, disc type and agitator type, for the purpose of improving the washing effect or preventing the washing articles from being entangled with each other.
FIG. 1 illustrates in detail one of the conventional disc type pulsator 10, which comprises a fixing part 11 formed at the center of the lower end portion thereof a protrusion 12 upwardly projected from the center of the upper end with predetermined height, and smoothly curved blades 13 extending from the central portion to the outer periphery.
This type of pulsator 10, as shown in FIG. 2, is mounted in the inside of a wash tub 20 as to be rotated by a driving motor 30. When the power is on, it rotates back and forth and further blades 13 thereof create the water flow indicated by the arrow in FIG. 2. In addition, the washing articles are being laundered by following aforementioned water flow in the wash tub 20.
However, in a washing machine provided with this pulsator 10, the washing articles being gathered to the central portion of the pulsator 10 and located only at the bottom of the wash tub 20 due to water flows towards the central portion of the pulsator while the pulsator is continued to rotate. Therefore, there is a problem that the washing articles are rubbed with the blades 13 of the pulsator 10 and damaged or even torn by it. In addition, the washing articles are being entangled with each other according to the directional change of the rotation of the pulsator, and thus such pulsator has a problem in that it is impossible to expect a high washing effect due to the entanglement of the washing articles and necessary to disentangle the washing articles after dehydrating.
SUMMARY OF THE INVENTION
It is an object of the present to provide a new type pulsator having an elevating member adapted to push up the washing articles by up-and-down motion during washing cycle, wherein the elevating member is formed at the central portion of the pulsator and repeatedly moves upwards and downwards repeatedly along a spiral groove engraved on the outer surface of a rotating member.
It is another object of the present invention to provide a pulsator in which spring means is provided in the elevating member of the pulsator so as to generate up-and-down water flow smoothly in the wash tub.
It is further another object of the present invention to provide a pulsator which are provided with an elevating member oscillating vertically by the rotation of a rotating shaft and a head swingably fixed to the upper end of said elevating member so that washing operation is carried out without entanglement of the washing articles.
It is further another object of the invention to facilitate the creation of non-symmetrical water flow in the wash tub so as to improve the washing power of the washer.
It is further another object of the present invention to increase the frictional force of the elevating member against the water flow so as to facilitate up-and-down motion of the elevating member.
According to the present invention, it is possible to prevent the washing articles from being damaged since the washing articles are being moved upwards and downwards by the pulsator having elevating member. Also, in the washing machine provided with the pulsator according to the present invention, since the washing operation is carried it can be achieved drastically improved effect.
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, and wherein:
FIG. 1 is a cross sectional view showing a conventional pulsator;
FIG. 2 is a partially cutaway view showing flow line of the washing water in a washing machine having a conventional pulsator;
FIG. 3 is a cross sectional view showing operating state in a washing machine of the first embodiment according to the present invention,
FIG. 4 is a enlarged sectional view showing the engagement of an elevating member and a rotating member in FIG. 3;
FIG. 5 is a section view of the pulsator of the second embodiment;
FIG. 6 is a partial perspective view illustrating the operating relation between the elevating member and the rotating member in the second embodiment;
FIG. 7 is a partially cutaway view showing flow line of the washing water in a washer having the pulsator of the second embodiment;
FIG. 8 is a sectional view showing a assembling state of the rotating member and the elevating member of the third embodiment;
FIG. 9 is a cross sectional view illustrating flow line of the washing water due to the rotating of the pulsator of the third embodiment;
FIG. 10 is a cross sectional view illustrating flow line of the washing water due to the rotating of the pulsator of the fourth embodiment;
FIG. 11 is an exploded perspective view showing the principal parts of the fourth embodiment;
FIG. 12 is a sectional view showing assembled state of the principal parts in FIG. 11;
FIG. 13 is a sectional view illustrating flow line of the washing water due to the rotating of the pulsator of the fifth embodiment;
FIG. 14 is a enlarged sectional view showing the engagement of the elevating member and the rotating member is FIG. 13;
FIG. 15 is a sectional view illustrating flow line of the washing water due to the rotating of the pulsator of the sixth embodiment;
FIG. 16 is a perspective view showing assembled state of the elevating member and the rotating member of the sixth embodiment.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The first embodiment of the present invention will be described in detail with reference to FIGS. 3 and 4. Referring to FIG. 3, in a wash tub 101 there is mounted vertically a rotating shaft 102 driven by the driving force of a driving motor 114 which is transmitted through a pulley 116, a belt 118 and a pulley 117, and to the rotating shaft 102 is mounted a pulsator 103 as to be rotated to generate water flow in the wash tub 101. To the central portion of the pulsator 103 is inserted a rotating member 105 by using a fixing part 104 formed at the lower portion thereof, and a dimple 120 is formed on the upper end of the rotating member 105. In addition, the rotating member 105 is coupled with an elevating member 122 to generate heart-shaped water flow in the wash tub 101, wherein the elevating member 122 is provided with a guiding protrusion 121 being contacted with said dimple 120 so as to move along the surface of said dimple 120.
Therefore, when the driving motor 114 starts to rotate, the driving force of the driving motor 114 is transmitted to the rotating shaft 102 through the pulley 116 mounted on the upper end of the motor shaft 115, the belt 118 and the pulley 117 mounted on the lower end of the rotating shaft 102, and the pulsator 103 which is coupled with the rotating member 105 mounted on the upper end of the shaft 102 begins to rotate. At the same time, the guiding protrusion 121 projected from the inside of the elevating member 122 moves along the surface of the dimple 120, so that the elevating member begins to move upwards and downwards so as to push up the washing articles. Thus, the washing operation is to be completed without entanglement of the washing articles.
Next, the second embodiment of the present invention will be described in detail with reference to FIG. 5 through FIG. 7. FIG. 5 is a sectional view showing a pulsator according to the present embodiment, and FIG. 6 is a partial perspective view illustrating the operating relation between the elevating member and the rotating member.
Referring to FIG. 5 and FIG. 6, the rotating member 211 having a scroll groove 211a engraved on the surface is projected upwardly from the central portion of the pulsator, and the elevating member 212 is disposed over the rotating member to move upwards and downwards along the scroll groove 211a.
In the present embodiment, as shown in FIG. 7, when the pulsator 210 starts to rotate, the washing water in the wash tub 220 flows along the flow line indicated by the arrow, and the elevating member 212 repeatedly moves upwards and downwards along the scroll groove 211a so as to push up the washing articles. Thus, gathering of the washing articles to the central portion of the pulsator can be prevented.
At the central portion of the pulsator, there are formed an operating space A between the insides of blades 213 and the outer surface of the rotating member 211, and an inward flange 213a extending from the inside of the blades 213 formed at the upper portion of the operating space A. And there are formed the scroll grooves 211a in a predetermined angle on the surface of the rotating member 211, and a returning groove 211b is formed between the upper scroll groove and the lower scroll groove.
On the other hand, the elevating member 212 disposed over the rotating member 211 has a hollow part in which the rotating member 211 is received, and at the inner peripheral surface of the elevating member 212 is formed a sliding protrusion 212a adapted to be inserted into the scroll groove 211a, and an outward flange is formed on the skirt of the elevating member so as to engage with the inward flange 213a.
In this pulsator 210 according to the second embodiment, the sliding protrusion 212a of the elevating member 212 is engaged with the scroll groove 211a and the lower end of the elevating member 212 is rotating into the operating space. As the rotating member 211 rotates, the sliding protrusion 212a moves upwards along the scroll groove 211a and moves downwards to the lower scroll groove through a returning groove 211b after reaching to the upper end of the scroll groove 211a, and repeats this operation as long as the pulsator rotates. And the elevating member 212 being moved along the scroll groove 211a is contacted with the inward flange 213a and restricted upward motion thereof by the flange 213a, so that separating of the member 212 from the operation space A can be prevented.
In this embodiment, it is possible to present the washing articles from being damaged since the washing articles being concentrated to the bottom of the wash tub 220 are pushed up by the elevating member.
Next, the third embodiment of the present invention will be explained with reference to FIG. 8 and 9. FIG. 8 is a sectional view illustrating the assembled state of the rotating member and the elevating member, and FIG. 9 is a schematic view showing flow line of the washing water due to the rotation of the pulsator.
Referring to FIG. 8 and 9, the pulsator 320 includes the rotating member 321 which has a sliding portion 321a formed on its upper outer surface and a guiding dimple formed on its upper end surface, the elevating member 322 whose lower end portion is slidably contacted with the sliding portion 321a of the rotating member 321, and a coil spring 323 which is elastically supported between the upper end of the rotating member 321 and the inner bottom surface of the elevating member 322.
The upper end of the rotating member 321 is inserted into the hollow portion of the elevating member 322, and the skirt of the elevating member 322 extends to the hollow portion 322a so as to form an inward flange 322b. The upper portion-of the rotating-member 321 is inserted into the hollow portion 322a through the open end of the elevating member 322, and a sliding protrusion 322c projected downwardly from the inner surface of the member 322 is slidably contacted with the guiding dimple formed on the upper surface of the member 321 and slidably contacted with the sliding portion 321a.
In the above described embodiment, as shown in FIG. 9, when the pulsator 320 begins, to rotate back and forth, the heart-shaped water flow is generated in the water filled in the wash tub 301, and the elevating member 322 moves upwards and downwards along the guiding dimple formed on the upper surface of the rotating member 321 being rotated together with the pulsator 320. At this time, if the pressure of the washing articles and the washing water which flows along the flow line exceeds biasing force of the coil spring 323, the coil spring 323 is compressed and then the elevating member 322 moves downwards, if the biasing force of the coil spring is larger than said pressure, the coil spring is restored to the original state so that the elevating member 322 is moved upwards instantaneously.
In this type of pulsator, the elevating member 322 elastically supported by the coil spring 323 repeatedly moves upwards and downward according to variation of said pressure. Therefore, up-and-down water flow can be easily and smoothly generated through the motion of the elevating member 322 so that the entanglement of the washing articles is prevented.
In addition, the fourth embodiment of the present invention will be described in detail with reference to FIG. 10 through FIG. 12. FIG. 10 is a sectional view of the present embodiment, and FIG. 11 is an exploded perspective view showing the principal parts, and FIG. 12 illustrates the assembled state of the present embodiment. Referring to FIG. 10 through 12, the rotating member 405 in which the fixing part 404 is formed at the lower end thereof and its upper portion is formed to be broadened in its diament gradually toward the upper end is coupled with the pulsator 403 provided in the bottom of the wash tub 401 to generate the water flow, and a spiral groove 406 is engraved on the inner peripheral surface of the rotating member 405. Two guiding protrusions 408,408 formed at both sides of the lower outer surface of the elevating member 407 are inserted into the spiral groove 406 so as to the elevating member 407 moves upwards and downwards along the spiral groove 406. At the middle of the upper end of the elevating member 407 there is engraved an inserting groove 409 having guiding holes 410,410 formed at both sides thereof.
Further, a circular cone-shaped head 411 is disposed on the tapered open end of the rotating member 405, and as the elevating member 407 moves upwards and downwards, the head 411 pivots on shafts 412,412 projected from the both sides of the lower portion thereof. The lower portion of the head 411 is inserted into the inserting groove 409, and the shafts 412,412, then the shafts 412,412 of the head are inserted into the guiding holes 410,410. On the one end of the bottom surface there is formed a slant face S having a predetermined angle α, and a coil spring is provided between the inserting groove 409 and the slant face S for giving elastic force to the head 411.
In the present embodiment, as shown in FIG. 10 through FIG. 12, when the driving motor 414 disposed under the wash tub 401 starts to rotate, the driving force of the driving motor 414 is transmitted to the rotating shaft 402 through the pulley 416 mounted on the upper end of the motor shaft 415, the belt 418 and the pulley 417 mounted on the lower end of the rotating shaft 402, and then the pulsator 403 which is coupled with the rotating member 405 mounted on the upper end of the shaft 402 begins to rotate. At this time, the elevating member 407 whose guiding protrusions 408,408 are inserted into the spiral groove 406 engraved on the inner peripheral surface of the rotating member 405, moves upwards along the spiral groove 406 as indicated by the phantom line in FIG. 12, and also the circular cone-shaped head 411 connected with the upper end of the elevating member 407 moves upwards.
When the head 411 reaches the upper limit, the head 411 becomes to be inclined as indicated by the phantom line in FIG. 12 by the coil spring 413 disposed under the slant surface S having a predetermined angle α. Thus while the head becomes to be inclined to one side, the head beats the washing articles. When the guiding protrusions 408,408 of the elevating member 407 move downwards along the spiral groove 406, the head 411 being inclined restores to the original state and beats the washing articles again so that non-symmetrical water flow is generated by the beating of the head as shown in FIG. 10.
Accordingly, the entanglement of the washing articles can be minimized and the washing is carried out effectively by the non-symmetrical water flow.
Next, the fifth embodiment of the present invention will be explained with reference to FIG. 13 and 14. Referring to FIG. 14, the upper surface 512 of the elevating member 502 is inclined in a predetermined angle β. The rotating member 513, the pulsator 503 and the elevating member 502 are operated in similar manner described in foregoing embodiments.
Therefore, the elevating member 502 is rotated by the driving force of the driving motor 508 which is transmitted through the rotating shaft 509 and the rotating member 513, and the elevating member 502 moves upwards and downwards by the contacts between the guiding protrusion 510 and the dimple formed on the upper surface of the rotating member 513. When the elevating member 502 begins to rotate and oscillate vertically, the non-symmetrical water flow is generated in the wash tub 501 by the operating of the slanted upper surface 512. Accordingly, the entanglement of the washing articles can be minimized, and the washing is carried out effectively by the non-symmetrical water flow.
Next, the sixth embodiment of the present invention will be explained with reference to FIG. 15 and 16. Referring to FIG. 16, on the upper outer surface of the elevating member are disposed fins 623,623 maintaining an equal distance to each other. And the rotating member 605, the pulsator 603 and the elevating member 622 are operated in similar manner described in foregoing embodiments.
Therefore, the elevating member 622 is rotated by the driving force of the driving motor 614 which is transmitted through the rotating shaft 602 and the rotating member 605, and the elevating member 622 moves upwards and downwards by the contacting between the guiding protrusion 621 and the dimple formed on the upper surface of the rotating member 605. At this time, the fins 623,623 are struck against the water flow which flows around the elevating member 622 in opposite direction of the rotating, then resisting force acts to the fins 623,623 so as to facilitate the vertical oscillation of the elevating member. Accordingly, the elevating member 622 smoothly moves upwards and downwards, and the entanglement of the washing articles can be reduced.
In the present embodiment, although the elevating member is disclosed as having two fins 623,623, the elevating member may have plural fins or slanted fins.
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 in the scope of the following claims.
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The invention relates to a pulsator with an improved structure and more particularly to a pulsator having punching function used in the washing machine. The pulsator of the present invention is composed of such improved structure that a rotating member has a guiding dimple formed on the its upper end surface, and an elevating member has a guiding protrusion projected from the inner surface. According to such pulsator, non-symmetrical water flow and up-and-down water flow can be generated easily so that the entanglement of the washing articles can be minimized, and the washing is carried out effectively.
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BACKGROUND OF THE INVENTION
The present invention relates to a locking device for seat belts intended for vehicles, of the type in which a strap forming a part of the seat belt is automatically drawn into a casing and wound up on a rotatable coiling shaft when the belt is not used, to temporarily lock the shaft.
Is is previously known to arrange locking of the shaft in a coiling device by providing the shaft with a body rotating with the shaft, in said body there being arranged a number of displaceable locking bodies arranged to be moved to a locking position in which they engage with a fixed toothed ring outside the rotational path of the rotating body, so that the shaft is prevented from rotating and withdrawal of the strap of the seat belt cannot take place, whereby the person wearing the seat belt is safely kept in place. Displacement of the locking bodies to the locking position can thereby take place either in response to a rapid withdrawal of strap, the locking device thus being responsive to strap movement, or in response to an acceleration or retardation of the vehicle, the locking device thus being responsive to vehicle movement. The locking device can also be made so that it is responsive to both strap and vehicle movement.
By having the locking bodies in the known locking catch devices arranged in a body rotating with the shaft, the locking bodies will be brought into contact with the fixed toothed ring at a large velocity relative to it, which can result in bouncing and unreliable locking function. By reason of the displaceability of the locking bodies in the body rotating with the shaft, there also easily arises a rattling sound in the locking catch device caused by movements or vibrations of the locking bodies even for slow withdrawal of strap from the coiling device.
SUMMARY OF THE INVENTION
The main object of the invention is to provide a coiling device of the type set forth in the introduction, which gives a quick and reliable locking function and in which the above mentioned drawbacks have been removed.
Since the locking bodies according to the invention are placed in a locking means which is stationary in relation to the rotational movement of the shaft, and engage with a ratchet on the shaft, there is no rattle from the locking bodies when the strap is withdrawn, since the locking bodies do not accompany the shaft in its rotation. Furthermore, since the locking bodies are displaced from a neutral position to a locking position in a path running in a direction such that the locking bodies move with the periphery of the ratchet when withdrawing the strap belt, the speed of the locking bodies relative to the ratchet can be substantially reduced in relation to what has been possible previously, whereby a more distinct and reliable locking function is obtained, as well as less wear. There is indeed a larger relative movement between the locking bodies and the locking means in which they are accomodated, but this relative movement can easily be taken up in the pockets in which the locking bodies are accommodated.
BRIEF DESCRIPTION OF THE DRAWINGS
Some embodiments of the locking device according to the invention will now be described in detail below while referring to the attached drawings.
FIG. 1 shows a cross section through a coiling device with a vehicle responsive locking catch device according to the invention.
FIG. 2 shows the locking mechanism itself of the locking device shown in FIG. 1.
FIG. 3 shows the guidance of the locking bodies of the locking device shown in FIGS. 1 and 2.
FIG. 4 shows a locking device according to the invention which is responsive to both vehicle and strap movement.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The coiling device shown in FIG. 1 for the strap in a seat belt comprises a coiling shaft 10, rotatably mounted in two parallel walls 11, 12, and on which a strap 13 being part of the seat belt can be wound up. The shaft is provided with two locking plates 14, 15 adjacent the insides of the walls 11, 12 to prevent axial displacement of the shaft, which at its lefthand end in FIG. 1 is provided with a helical spring 16, one end of which is attached to the shaft, the other end being attached to a casing 17 surrounding the spring, which casing is fixed to the adjacent wall 11. The helical spring is arranged for tensioning when the strap is wound off from the shaft and to automatically wind up the strap on the spindle again when the seat belt is not used. At its other end the shaft is provided with a ratchet wheel 18, having a toothed ring 19 and non-rotatably attached to the shaft and thus accompanying it on its rotation, the toothing on the ratchet wheel being shown more clearly in FIG. 2. A locking means 20 in the form of a circular ring is attached to the outside of the wall 12 by means of screws 21 concentrically about the shaft 10, the ring having an inner diameter which is somewhat larger than the diameter of the wheel 18, so that the wheel 18 can rotate freely in the ring. In the locking means 20 there are accomodated three locking bodies 22, as shown in FIG. 2. These locking bodies are arranged in pockets 23 having a deeper outer portion, seen radially, in which the locking bodies can lie without coming into contact with the ratchet wheel 18, and a shallower inner portion, seen radially, in which the locking bodies are placed when they are to engage with the ratchet wheel 18. The bottoms of the pockets incline obliquely in towards the periphery of the ratchet wheel in the direction, denoted by the arrow a, in which the ratchet wheel periphery travels when strap is unwound from the shaft. The shallower portion of each pocket is thus behind the deeper portion of the same pocket, as seen in the direction of travel of the shaft when uncoiling strap from the shaft. When moving from the deeper portion of the pocket, which provides the free or neutral position of the locking body, to the shallower portion of the pocket, which provides the locking position of the locking body, the locking body thus moves in the same direction as the ratchet wheel 18, whereby the difference in relative speed of the locking body and ratchet wheel will be comparatively small, when the ratchet wheel is engaged by the locking body.
A guide plate 24 is rotatably mounted on the shaft outside the ratchet wheel 18 and locking means 20, so that it does not accompany the rotation of the shaft. The guide plate is placed adjacent the ratchet wheel 18 and is provided with a guide slot 25 for each locking body 22, as is shown in FIG. 3. The locking bodies 22 consist of cylindrical rollers and are provided at their ends facing towards the guiding plate with a neck 22a projecting into the associated slot 25 in the guide plate. The diameter of the guiding necks and the dimensions of the guide slots are so matched that the movement of the locking bodies can be guided by turning the guide plate 24 about the shaft 10. The slots 25 in the embodiment shown are straight, and form an angle α with the radius. This angle should lie between 5° and 60°, preferably between 15° and 30°. The outer ends of the slots lie in front of the radius which goes through the centre of the respective slot seen in the direction, denoted by the arrow a, in which the shaft rotates when strap is wound off. Immediately outside the guide plate 24 there is a toothed wheel 26 arranged on the shaft 10, said toothed wheel 26 being non-rotatably fixed to the shaft and thus accompanies the shaft during its rotation. The toothed wheel is retained on the shaft by means of a circlip 27.
As is more clearly shown in FIG. 3, the guide plate 24 is provided with a projecting lug 28 on which a pin 29 is arranged. On this pin a pawl 30 is pivotably mounted, the pawl lying in substantially the same plane as the toothed wheel 26. The pin 29 is placed outside the circumference of the toothed wheel 26 and the tip of the pawl is so arranged that when the pawl is turned about the pin 29 (clockwise in FIG. 3) it will come into engagement with the teeth on the toothed wheel 26, so that the guide plate 24 is coupled to the shaft and is turned together with it when strap is drawn out. One end of a spring 31 is attached to the pin 29 and the other end is attached to a fixed point, so that the guide plate 24 can be returned to the original position in which it is when the shaft is not locked. The pawl 30 rests with its downward portion on a tiltable means 32 provided with a foot having its bottom surface resting against a flat surface in a cup 33. The tiltable means is arranged to tilt to an inclined position when the vehicle is accelerated or retarded in any direction, and thereby to lift the pawl 30 into engagement with the teeth on the toothed wheel 26. When the acceleration or retardation of the vehicle stops, the tiltable means 32 returns to its upright position, whereby the pawl can fall from engagement with the toothed wheel 26.
The device shown in FIGS. 1-3 works in the following way. When the tiltable means 32, e.g. due to heavy braking of the vehicle, moves to a tilted position, the pawl 30 is moved into engagement with the toothed wheel 26. If the person wearing the seat belt moves forward so that strap is drawn out, the guide plate 24 will turn with the shaft because of the coupling provided by the pawl between the wheel 26 and the guide plate 24. When the guide plate turns, the locking bodies 22 will be displaced from their neutral positions to their locking positions because of the function of the guiding slots 25, whereby the continued rotation of the shaft is prevented, so that further withdrawal of strap cannot occur. When tension in the strap ceases, the helical spring 26 will retract a portion of the strap into the coiling device, whereby the toothed wheel 26 is turned at least somewhat in the opposite direction, so that the pawl 30 is released and the guide plate 24 can be turned back to its normal position by the spring 31. In this embodiment, locking of the shaft is accomplished by the locking device as a result of cooperation between the vehicle-responsive means 32 and a pull on the strap in the direction of withdrawal.
The embodiment shown in FIG. 4 agrees in principle with the embodiment shown in FIGS. 1-3 but with a modification for providing a locking device which is responsive both to vehicle and strap. In order to simplify the description, corresponding items have been given the same reference numerals in FIGS. 1 and 4.
In the embodiment according to FIG. 4, to provide strap responsiveness in the locking device, the guide plate 24 is equipped with a ring of teeth 34 forming a bowl-like space around the centre of the guide plate. A disc 35 is accommodated in this space in such a way about the shaft that it can be displaced radially in relation thereto in response to the action of centrifugal force when the shaft is rapidly rotated, and is thereby caused to come into engagement with the teeth 34 on the guide plate 24, by means of a tooth or other projecting portion. The radially displaceable disc 35 is provided with a central hole which is larger than that which would be required for the shaft, and this hole is so shaped that the disc can be displaced in a radial direction on the shaft, although it accompanies the shaft during rotation of the latter. The disc 35 is also spring biassed such that the disc is returned to its normal, neutral position, in which there is no coupling between the guide plate 24 and the shaft 10. The toothed wheel 26, as in the previous embodiment, is arranged at the end of the shaft, and the pawl 30 is arranged in the same plane as the toothed wheel 26 in this case as well. The strap responsiveness of the locking device is thus achieved by means of the guide plate 24 and the radially displaceable means 35 actuated by centrifugal force. On rapid withdrawal of the strap there is a rapid rotation of the shaft and this rotation provides the centrifugal force required to actuate the means 35. After the guide plate 24 has been coupled to the shaft, further rotation of the shaft due to withdrawal of strap results in turning the guide plate, so that the locking bodies 22 are brought into engagement with the ratchet wheel 18 in the way described above. The vehicle-responsive locking of the shaft is provided in exactly the same way as described for the embodiment shown in FIGS. 1-3.
In the embodiment according to FIG. 4, instead of the means 35 controlled by centrifugal force, an inertia control means of known type can be used, the inertia controlled means in its rotation in relation to the shaft causing a spring, a plate or the like to be moved outwards for providing coupling between the guide plate and the shaft to turn the guide plate.
Even if only a few embodiments have been described and indicated above, it is obvious that a great number of embodiments and modifications are possible within the scope of the invention. For example, the ratchet wheel can be provided with teeth on a side surface instead of on the circumference, and the locking means can consist of one or more parts and does not need to have the shape of a ring surrounding the ratchet wheel. The locking bodies can further be formed as rods, balls or latches and thus do not need to consist of cylindrical rollers. Guiding the locking bodies can also be done with guiding strips or similar elements on the guide plate instead of elongate through slots in the plate, and neither does the latter need to be circular. The guide plate does not need to be mounted on the shaft but can be rotatably mounted on the locking means, for example. The coupling between the guide plate and the shaft, or a means non-rotatably fixed to the shaft, can be provided by many different forms of means controlled by centrifugal or inertia force to provide a strap responsive locking device, and by means of many different types of latches which can be controlled by pivotable means or pendulums or the like, to provide a vehicle-responsive locking device. The coupling can, furthermore, easily be provided magnetically, e.g. by closing a current circuit by a sensing means common to all the seat belts in the vehicle. Returning the guide plate and the locking bodies to the respective neutral positions can be done using arbitrary spring means. The locking bodies can further be arranged for displacement in an axial direction from a neutral position to a locking position.
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A locking device for seat belts intended for vehicles of the type in which a strap being a part of the seat belt is automatically drawn into and wound up on a rotatable coiling shaft when the seat belt is not used, to temporarily lock the shaft. The device comprises a ratchet means non-rotatably arranged on the shaft; a locking means fixedly mounted in relation to the shaft; at least one locking body accommodated in the locking means and arranged for displacement from a neutral position to a locking position in which the locking body engages with the ratchet means for preventing rotation of the shaft; and a rotatably mounted guiding means. The guiding means is provided with a guiding surface for the locking body and is coupled to the shaft at the beginning of the locking operation to be turned by the shaft on its rotation due to withdrawal of strap from a normal position to a locking position and thereby to move the locking body to the locking position.
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FIELD OF THE INVENTION
[0001] An inductor coil is bonded to the surface of an electrically insulated perforated steel susceptor to form an integral unit for inductively coupling energy from the inductor to the susceptor.
BACKGROUND OF THE INVENTION
[0002] Solid to liquid transformations by technology described in Lasko patents U.S. Pat. No. 5,584,419 and U.S. Pat. No. 7,755,009 require inductor coil forms that often impede material flow. Solid or particulate form electrically nonconductive materials are presented to one surface of an inductively heated perforated susceptor for melt transformation upon passing to the other side by gravity flow or mechanical pressure. When the susceptor form is a disc, it acts as a face of a cylindrical container for the process material. A cone form susceptor acts as a conical end of a cylindrical container. A cylinder form susceptor is a portion of the cylindrical container. These shapes are necessarily fully radial to accomplish an evenly distributed coupling of the magnetic field. The objective of the inductor coil design for this melting process is to distribute the magnetic field intensity in proportion to the volume flow over the surface of the susceptor. Efficient transfer of energy to the susceptor requires placement of the individual inductor elements in close proximity to the susceptor surface. The number of elements [off-set concentric turns or spiral turns] per unit area of the susceptor surface is varied to distribute the magnetic field intensity and resulting energy transfer from the inductor coil to the susceptor. These variations control the influence of the inductor coil magnetic field edge effect and inter-turn deviation [flux leakage].
[0003] Sheets of industry standard staggered round hole perforated steel are used to construct susceptors of disc, cone and cylinder form. The size and number of perforations in the susceptor are chosen to maximize the surface area of the susceptor for thermal conduction to the process material, while restricting open area to preserve thin sheet strength and adequate cross sectional area for even induced current flow. The thermal conductivity and temperature variable viscosity of the process material further defines the hole size. An open area of approximately 50% meets this requirement for most materials. The material must flow through the susceptor in unimpeded volume related to the energy transferred at any point on the susceptor to impart a homogeneous material temperature.
[0004] Processing different materials in the same apparatus requires purging the previous material with the new material. Additional surfaces of inductor coil supports and the coil occupied area add to the volume of material lost to this process. Lesser viscosity materials in gravity flow will not adequately displace materials of greater viscosity. Removing the inductor and susceptor for chemical cleaning is not an attractive alternative. The process start and stop interval is lengthened by the total thickness of the inductor coil and susceptor assembly. Because the susceptor is the material containment vessel or a part there of, support for this item in the apparatus is complicated by the necessary close proximity position of the inductor coil.
[0005] This invention provides a method of meeting these physical and electrical requirements by direct placement of the inductor coil on the susceptor surface and perforating the inductor coil with axis and diameter coincident holes. The hydraulic pressure required to pass material through this thermal interface is reduced to that of the susceptor alone. The inductor coil does not need to be separately supported in the material flow path. Similar materials can be processed with minor volume displacement of the previous material in the apparatus. Extraction of the integral inductor-susceptor for chemical cleaning is made practical by requiring only the removal of an electrical connection and striping the surface of a single unit of simple form.
[0006] When the adjacent inductor coil material is axis coincidentally perforated, its electrical conducting cross section is diminished. The resistance of the total remaining conductor cross-section must remain low enough to support the desired amount of high frequency current having electrical energy losses that are thermally transferable to the process material. The thickness of the inductor coil is increased to preserve the required minimum cross section.
[0007] The inductor is made integral with the susceptor by direct placement on an electrically insulated susceptor surface. This bond provides an accurate and mechanically stable orientation of the inductor in closest proximity of the susceptor. This is achieved in one embodiment of the invention by plating the inductor coil on one or both surfaces of a porcelain enamel coated perforated steel disc. The perforated sheet steel disc is etched to radius the holes edges and decarburize the surface. The entire disc surface and holes are coated with 0.009″ of porcelain enamel. The disc is electroless copper plated, pattern masked, etched, striped, electroplated, and refired. The coefficient of thermal expansion of the steel disc susceptor, porcelain enamel coating, and copper overlay are close enough to maintain an effective bond for typical maximum process temperature excursions of 400° F.
[0008] The process residency time for most thermoplastic materials is a few seconds. Power applied at 20 to 50 watts/sq.″ will melt most thermoplastic materials at gravity pressure on the susceptor surface. The frequency of the power applied to the inductor coil is 40 to 100 KHz. The process temperature can be precisely controlled by placing a thermocouple on the susceptor to signal a controller for modulating the high frequency power applied to the inductor.
DESCRIPTION OF THE DRAWINGS
[0009] FIG. 1 is a cross section of an integral inductor/susceptor.
[0010] FIG. 2 is an isometric view of a 90° section of an integral inductor-susceptor having axis coincident perforations.
DETAILED DESCRIPTION OF THE INVENTION
[0011] FIG. 1 is a cross section of the edge of a 15″ dia. 19 ga. staggered pattern perforated sheet steel disc susceptor 1 . Susceptor 1 is coated with 0.009″ porcelain enamel 2 . Magnetic field inductor coil 3 is constructed of 22 rectangular turns of copper alloy screen printed and plated to 0.020″ thickness on the porcelain enamel 2 surfaces. Individual inductor coil turns 4 are identified as A through D. Turns A and B are the first and second turns of the inductor introduced at edge HF power entry point 5 . Holes in the center position turn are plated as a printed circuit via to pass current to the opposite side of susceptor 1 . A mirror image of inductor coil 3 is placed on the opposite side of the susceptor to return the current to edge HF power entry point 5 . The polarity signs (+/−) 6 indicate the instantaneous half cycle direction of the current flow required to make the magnetic fields 7 and 8 additive as intercepted by the susceptor. The field force lines 9 intercept the susceptor 1 with equal intensity. All susceptor holes 10 are 0.094″ diameter prior to applying porcelain enamel 2 . Arrows 11 indicate the flow of melting material passing through the integral inductor-susceptor. This arrangement of the coil and susceptor results in minimum heat energy remaining in the inductor-susceptor as power is turned off. It is most appropriate for applications where a fast start-stop of the melt flow is desirable.
[0012] FIG. 2 is a shaded isometric view of a 90° segment of a coated perforated disc susceptor with a spiral copper coil bonded to the surface. The individual turns 12 of the inductor coil are of differing width to even the magnetic field intensity profile across the disc. The perforated disc susceptor section 13 is coated with 0.009″ thick porcelain enamel that is to too thin to depict relative to its 0.040″ thickness and the individual turns 12 thickness of 0.020″. Perforation holes 14 in individual turns 12 are axis aligned with those of susceptor section 13 . Staggered hole perforated sheet steel is preferred for this construction to aid in preserving individual turn cross section at all segments of its track.
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An induction heating inductor and perforated susceptor are formed as an integral unit to provide a low cost, physically stable, efficient, and easily cleaned unit.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention refers to a pull-up circuit for input/output terminals of electronic appliances.
2. Description of the Related Art
In the prior art, pull-up resistances are used in connections between digital appliances, for example between computers and printers. In fact in communications between computers and printers the lines that carry the data are terminated by pull-up resistances with a set value. Said resistances are arranged between each data line and the power supply and each data line is connected to a pin or terminal of an interface, i.e., a data input/output (I/O) pin.
If we consider any pull-up resistance Rp arranged between an I/O pin and a terminal of the cable on which a supply voltage Vcc is present, as shown in FIG. 1, it is possible that when the voltage on the I/O pin is higher than the supply voltage Vcc or vice versa there is an undesired flow of current between the I/O pin and the power line. Said current flow consumes energy, which consumption must be as low as possible in many applications such as portable appliances of small dimensions.
BRIEF SUMMARY OF THE INVENTION
An embodiment of the present invention is a pull-up circuit for input/output terminals of electronic appliances that enables the disadvantage described above to be lessened.
The pull-up circuit is arranged between an input/output terminal and a supply-voltage terminal, and includes a first transistor and a resistance connected serially and coupled between said input/output terminal and said supply-voltage terminal, circuitry suitable for driving said transistor so as to switch it on or off depending on whether the values of the voltage of the input/output terminal belong or do not belong to a set range of voltage values within the supply-voltage value. As a result, pull-up circuit minimizes the absorption of current on the input/output terminals and on the supply-voltage terminals.
BRIEF DESCRIPTION OF THE SEVERAL VIEWS OF THE DRAWING(S)
The characteristics and advantages of the present invention will appear evident from the following detailed description of its embodiments thereof, illustrated as non-limiting examples in the enclosed drawings, in which:
FIG. 1 is a diagrammatic view of a pull-up resistance used in a circuit according to the prior art;
FIG. 2 is a diagrammatic view of the circuit according to an embodiment of the present invention;
FIG. 3 is a more detailed diagrammatic view of the circuit in FIG. 2;
FIG. 4 is a diagram of the variation in currents on the terminal I/O on the supply-voltage terminal depending on the voltage VI/O on the terminal I/O using the circuit shown in FIG. 3;
FIG. 5 is a diagram of the variation in currents on the terminal I/O and on the supply-voltage terminal depending on the voltage VI/O on the terminal I/O using a pull-up resistance as in FIG. 1 .
DETAILED DESCRIPTION OF THE INVENTION
With reference to FIG. 2 a pull-up circuit according to the present invention is diagrammatically shown. The circuit comprises a p-channel MOS transistor M 1 serially connected to a resistance Rs between the supply Vcc and input/output terminals I/O, preferably an input/output terminal for digital data of an electronic appliance not shown in the Figure. More precisely, the source terminal of the transistor M 1 is connected to the supply-voltage terminal Vcc, the drain terminal is connected to a terminal of the resistance Rs, the other terminal of which is connected to the terminal I/O. The dimensions of the transistor M 1 should be such that the sum of its switch-on resistance Ron and of the resistance Rs falls within the specifications required for the value of the pull-up resistance.
The gate of the MOS transistor M 1 is driven by circuitry comprising a driving device 1 coupled to the terminals Vcc and I/O; device 1 commands the switch-on or the switch-off of the transistor M 1 , depending on the values assumed by the voltage VI/O on the input/output terminal I/O and on the power supply Vcc.
The circuitry also comprises another device 2 coupled to the terminals Vcc and I/O that supplies the bulk of the MOS transistor M 1 and is coupled to the device 1 ; the device 2 enables the bulks of the MOS transistors of the circuit to be biased to the highest potential between a voltage value slightly below Vcc and a voltage value slightly below or the same as the voltage on the terminal I/O.
FIG. 3 describes in greater detail the circuit of FIG. 2 . Device 1 comprises a first p-channel MOS transistor M 10 and a second n-channel MOS transistor M 11 , with drain terminals connected together, the gate terminals being connected to the supply-voltage terminal Vcc whilst the source terminal of the transistor M 11 is grounded and the source terminal of the transistor M 10 is connected to its bulk terminal. The device 1 also comprises third and fourth p-channel MOS transistors, M 12 and M 13 , the source terminals of both of which are connected to the supply-voltage terminal Vcc; the transistor M 12 has its gate terminal coupled to the input/output terminal I/O and has its drain terminal connected to the drain terminals of the transistors M 10 and M 11 and to an output terminal Out 1 of the device 1 that is connected to the gate terminal of the transistor M 1 ; the transistor M 13 's gate terminal is grounded and its drain terminal is connected to the terminal I/O. The transistors M 10 -M 13 have their bulk terminals coupled to an output terminal Out 2 of the device 2 .
The transistor M 13 is always switched-on and its switch-on resistance is much greater than the sum of the resistances Rs and of the switch-on resistance Ron 1 of the transistor M 1 .
When the voltage on the input/output terminal I/O is high (forced by the electronic appliance to which the terminal I/O is connected) so as to keep the transistor M 12 switched off, the voltage on the gate terminal of the transistor M 1 is at a low value because the transistor M 11 is switched on; in this way the transistor M 1 is switched on and for this reason there is a current between the supply Vcc and terminals I/O via the resistances Rs and Ron 1 .
When the voltage on the input/output terminal I/O is low (forced by the electronic appliance to which the terminal I/O is connected) so as to switch on the transistor M 12 , the voltage on the drain terminal of the transistor M 12 and therefore on the gate terminal of the transistor M 1 increases and thereby causes the transistor M 1 to switch off and prevents the flow of current from the terminal Vcc towards the terminal I/O. This occurs for as long as the voltage on the terminal I/O is lower than the difference between the supply voltage Vcc and the voltage V 12 provided by the threshold voltage Vth 12 and a voltage Vx 1 that indicates the amount by which the source-gate voltage Vgs of the transistor M 12 must exceed the threshold voltage Vth 12 in order to switch off the transistor M 1
VI/O<Vcc −( Vth 12 + Vx 1 ).
The voltage Vx 1 needs to be added to the threshold voltage Vth 12 to offset the effect of the transistor M 11 on the drain terminal of the transistor M 12 ; the transistor M 11 is always switched on unless the voltage Vcc is zero or near to zero and the value of the voltage Vx 1 depends on the dimensions of transistors M 11 and M 12 .
The transistor M 13 ensures that when the terminal I/O is disconnected from the electrical appliance to which it is connected and the voltage on the terminal I/O is at a low or high value, the value of the voltage on the terminal I/O reaches the supply voltage Vcc so as to enable the switch-off of the transistor M 12 and consequently enable the transistor M 1 to be switched on.
The device 2 enables biasing of the bulk terminals of the p-channel MOS transistors M 1 , M 10 , M 12 , M 13 to the highest potential between a voltage value slightly less than the supply voltage Vcc and a voltage value slightly less or the same as the voltage on the terminal I/O. Said device comprises a p-channel MOS transistor M 21 with a gate terminal connected to the supply voltage Vcc, the drain terminal being connected to the drain terminal I/O and the source and bulk terminals being connected to the output terminal Out 2 of the device 2 . The device 2 also comprises two p-channel MOS transistors M 22 and M 23 , both being connected as a diode and sharing a gate terminal and being connected to output terminal Out 2 , whereas the source terminal of the transistor M 22 is connected to the supply-voltage terminal Vcc and the source terminal of the transistor M 23 is connected to the terminal I/O. If the supply voltage Vcc is higher than the voltage on the terminal I/O the voltage on the gate terminals of the transistors M 22 and M 23 and therefore on the terminal Out 2 will be the same as Vcc−Vth 22 wherein Vth 22 is the threshold voltage of the transistor M 22 . If the voltage VI/O is higher than the supply voltage Vcc, considering the threshold voltages of the transistors M 23 and M 21 , the voltage on the terminal Out 2 will vary from the value VI/O−Vth 23 (where Vth 23 is the threshold voltage of the transistor M 23 ) to a value that is the same as the voltage on the terminal I/O due to switch-on of the transistor M 21 .
If the voltage on the terminal I/O is high and voltage Vcc=0, the transistor M 12 is switched off, the transistor M 10 is switched on and the transistor M 1 is switched off. In this case, as the voltage of the bulk of the MOS transistors is the same as the voltage on the terminal I/O, a current will run through the transistor M 21 and the transistors M 10 and M 11 .
VI/O>Vcc+Vth 10 +Vx 2 may occur, where the voltage Vx 2 is the voltage to be added to the voltage Vth 10 , the threshold voltage of the transistor M 10 , to switch off the transistor M 1 ; the voltage Vx 2 depends on the dimensions of the transistors M 10 and M 11 . In this case, as in the previous case, the transistor M 12 is switched off, the transistor M 10 is switched on and the transistor M 1 is switched off; as the voltage of the bulk of the MOS transistors is the same as the voltage on the terminal I/O, a current will flow through the transistor M 21 and the transistors M 10 and M 11 .
The circuit in FIG. 3 therefore acts as a pull-up resistance when the voltage on the terminal I/O is high with voltage values in the range between Vcc−(Vth 12 +Vx 1 ) and Vcc+Vth 10 +Vx 2 . For all the voltage values not included in said range the current absorbed by the terminal I/O is zero or very low. For example, said range of voltage values (Vcc−Vth 12 −Vx 1 , Vcc+Vth 10 +Vx 2 ) comprises voltage values that are no more than two volts above or below the value of the supply voltage Vcc; in fact, for example, the possible voltage values of Vx 1 , Vx 2 , Vth 10 and Vth 12 are Vth 10 =Vth 12 =0.9V, Vx 1 =0.4V and Vx 2 =0.5V.
The graphs in FIGS. 4 and 5 show variations in the currents lin/out on the terminal I/O and Icc on the supply-voltage terminal depending on the voltage VI/O for the circuit in FIG. 3 (FIG. 4) and for a prior-art circuit consisting of a pull-up resistance as in FIG. 1 (FIG. 5 ). The value of the supply voltage is Vcc=3V and the voltage VI/O varies between 0 and 7V. We can see that the currents lin/out and Icc for the circuit in FIG. 3 have values near zero except for a range of VI/O values around the VI/O=Vcc value, wherein the values of the currents lin/out and Icc for the circuits in FIGS. 3 and 1 coincide.
All of the above U.S. patents, U.S. patent application publications, U.S. patent applications, foreign patents, foreign patent applications and non-patent publications referred to in this specification and/or listed in the Application Data Sheet, are incorporated herein by reference, in their entirety.
From the foregoing it will be appreciated that, although specific embodiments of the invention have been described herein for purposes of illustration, various modifications may be made without deviating from the spirit and scope of the invention. Accordingly, the invention is not limited except as by the appended claims.
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A pull-up circuit for input/output terminals of electronic appliances is disclosed. The circuit is arranged between an input/output terminal and a supply voltage terminal and includes a first transistor and a resistance serially connected and coupled between the input/output terminal and the supply-voltage terminal and circuitry suitable for driving the transistor so as to switch it on or off depending on whether the values achieved by the voltage of the input/output terminal belong or do not belong to a set range of voltage values within the supply-voltage value.
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BACKGROUND OF THE INVENTION
This invention relates to the positioning of a synchronized picture at any desired location of the television raster including off the screen. This invention, more particularly, relates to such television positioning apparatus used with a television video synchronizer which is normally used for synchronizing the television signals.
These synchronizers have been introduced to synchronized broadcast sources to a local reference generator. A video synchronizer is an electronic unit that samples the analog input, converts it to a digital format, stores the digital data and operates on the digital data to deliver a desired analog output which is constructed from the sampled video. It is designed to automatically lock a nonsynchronous broadcast signal to a local reference generator and thus allow fully synchronous treatment of the incoming video for mixing the station programs. The nonsynchronous signal is digitized and stored in a memory. The input video signals are temporarily stored in the digital memory in predetermined nonvarying locations as prescribed by addresses from an address generator in such a way that reading the stored video out of the memory produces a video signal identical to the input video signal with the exception being that the timing of the output video is locked to the studio reference. The data is clocked out of the memory at a rate locked to the reference sync generator (usually the local station). This synchronizer isolates the input/output video lines and the output is fully synchronous in vertical, horizontal and color phases with the reference.
These video synchronizers make possible many special effects for relatively low additional cost. In a separate application entitled, "Television Picture Size Altering Apparatus" U.S. Pat. No. 4,134,128, filed Dec. 27, 1976, Robert N. Hurst describes the special effect of expansion or compression of the video by adding or eliminating samples stored in the digital memory. In a separate application entitled, "Television Picture Compressor" Ser. No. 862,180, filed Dec. 19, 1977, there is described a particular technique for reducing the size of a full frame or full field picture to a one-quarter size. Applicant's invention herein relates to the special effect of moving the reduced size or full size pictures on the displayed output.
SUMMARY OF THE INVENTION
An apparatus for moving the position of the pictures on the raster is provided. The apparatus is adapted for use with a video synchronizer of the type comprising means including an address generator responsive to television video for sampling same and storing the samples in nonvarying locations according to predetermined addresses from the generator and means responsive to the stored samples for providing a picture like that of the incoming television video. The apparatus senses the incoming video sync timing and provides moving of the picture by altering the storage addresses from the address generator.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram of a television video synchronizer;
FIG. 2 illustrates in graphical form typical television line and field standards useful for understanding of the invention;
FIG. 3 illustrates the relationship between the horizontal and vertical addresses and the picture monitor location;
FIG. 4 is a block diagram of one implementation of the present invention for moving the picture right to left and up and down;
FIG. 5 is a block diagram of a system for moving the picture right to left in an alternative embodiment; and
FIG. 6 is a block diagram of a system for inverting the chrominance.
DESCRIPTION OF THE INVENTION
Referring to FIG. 1, a signal (Video In) from a nonsynchronous source, such as an Electronic Journalism (EJ) camera, is coupled to an input terminal of a video synchronizer and applied to an input video processor 10 in which the incoming video signal synchronizing components and burst timing information are separated from the active picture information. The separated timing information is coupled to a write clock generator 13 which develops timing information in the form of 14.3 MHz pulses (four times the NTSC subcarrier frequency of 3.58 MHz), synchronous with the incoming signal timing information, for enabling an analog-to-digital (A/D) converter 11, buffer 12 and write address generator 22. The active picture information portion of the incoming video signal is bandwidth limited to 5.5 Mhz in the input video processor 10 and coupled from the output terminal of video processor 10 to the input terminal of A/D converter 11, of known form, where the signal is converted (sampled at a 14.3 Mhz word rate) into digital form consisting of 8-bit parallel code words.
The signal output of A/D converter 11, in the form of a digitally sampled input video signal, is coupled to a buffer 12 and, in turn, to picture memory 20 for storage. The digital picture information signal is stored at discrete locations in the memory in accordance with specific address codes referenced to burst, vertical and horizontal sync signals generated by the write address generator 22 in response to the related incoming signal timing information generated in the write address clock. In a typical synchronizer of the type illustrated in FIG. 1, constructed in accordance with known techniques and utilizing a clock rate of 14.3 MHz, each horizontal line period of 910 samples would be 63.5 microseconds. See FIG. 2. As illustrated in FIG. 2, the active picture area actually comprises 2421/2 lines with the other 20 lines being utilized for the vertical blanking interval. To completely store the 2421/2 active vertical picture information lines per field as well as the vertical interval signal processing information on lines 17, through 20, 256 lines are stored beginning the vertical line information storage at line 15.
The data stored in memory 20 is read out of memory into a buffer 30, which is, in turn, coupled to a digital-to-analog (D/A) converter 31, which converts the 8-bit code word back to a conventional analog picture by timing information and read address generated by read clock generator 33 and read address generator 23, which are synchronized to the local studio reference. The output of D/A converter 31 is coupled to an output video processor 32 in which the blanking interval, sync and burst corresponding to local studio reference are added to the recovered picture information to restore the output video signal to a complete composite video signal, as illustrated in FIG. 2. Thus, the picture information, which is stored in memory 20 from a nonsynchronous source is read out of the memory synchronous with the local studio reference, which makes the signal suitable for programming production requirements of mixing, special effects and switching similar to the manner in which a live camera, VTR tape or other source is used.
Memory control 21 completes the synchronizer of FIG. 1 and includes logic circuitry which responds to status signals from the write and read address generators identified in FIG. 1 as ready-to-write and read-to-read, respectively, so as to provide write and read signals to memory 20 to insure that reading and writing into the same address location does not occur simultaneously as would be the case where nonsynchronous video sources may drift ahead and behind the fixed local stuido reference. A particular memory control circuit and a more detailed description of the synchronizer of FIG. 1 is described in application of Robert S. Hopkins, Jr., U.S. Pat. No. 4,134,131, entitled "Digital Video Synchronizer", filed Dec. 30, 1976.
A particularly advantageous memory storage construction useful in a television signal synchronizer of the form illustrated in FIG. 1 is known as a coherent memory and is described in detail in the application of R. A. Dischert, et al., assigned to the same assignee and filed Dec. 30, 1976 and given U.S. Pat. No. 4,101,926 entitled "Television Synchronizing Apparatus". Using the coherent memory as described in the above cited application of Dischert, et al., the time period of each line during which information is to be stored is reduced to 52.5μ sec corresponding to the actual video image portion of the line, as illustrated in FIG. 2. Utilizing the same clock rate of 14.3 MHz, as previously described, the number of samples per line to be stored is reduced from 910 to 768. Particularly advantageous ways of providing of coherence of the image information is discussed in copending application of Hopkins, et al., entitled, "Memory Read/Write Organization For a Television Signal Processor" filed Dec. 30, 1976 and given U.S. Pat. No. 4,109,276. The synchronizer described is similar to that of RCA type TFS-121 sold by RCA Broadcast Systems, Camden, N.J. Other types of video synchronizers which store whole frames are described in several articles in SMPTE Journal. See Volume 82 of SMPTE Journal, page 300 thru 302, entitled "Digital Frame Storage for Television Video" by Scott Pursell and Harold Newby, Volume 84 of SMPTE Journal, pages 129 thru 134, entitled "Television Frame Synchronizer" by Kano, et al., and Volume 85 of SMPTE Journal, No. 6, June 1976, pages 385 thru 388, entitled "A Digital Framestore Synchronizer" by J. Brian Matley.
Shown in FIG. 3 is a digram illustrating memory addresses in the synchronizer as a function of position in the raster, as seen on a picture monitor. Shown for simplicity is only one of the television fields. In the synchronizer discussed here, there are 768 different addresses, or picture elements, in each horizontal line and 256 different horizontal line addresses in each field.
In implementing this invention, it is assumed, although not necessarily so, that only the active portion (See FIG. 2) of the video is stored. It is further assumed that the digital video will be read from the memory in such a manner that vertical address 0 occurs during line 15 (see previous discussion) of the output video (again this is not necessarily so but is used as an example) and that horizontal address 0 occurs at the point of the termination of horizontal blanking of the output video (again not necessarily so). With a 4 times subcarrier sampling clock (4×SC) horizontal address 767 will be approximately located at the termination of the active picture horizontal line.
In the normal synchronizing mode of operation, the input video will be stored in a manner identical to that described for reading the memory except timing references of line 15 and the end of horizontal blanking refer to the input video rather than the output video. The circuitry incorporated in the basic synchronizer will guarantee that the horizontal address is set to 0 at the termination of horizontal blanking and is incremented by 1 with each and every clock pulse during every horizontal line. Likewise, the circuitry will guarantee that the vertical address is set to 0 on line 15 and is incremented by 1 each and every horizontal blanking interval. These processes occur simultaneously and independently for writing into the memory and reading from the memory. For example see FIG. 4.
The write address generator of a typical synchronizer of the type in FIG. 1 would include, for example, a first horizontal counter 22a as illustrated in FIG. 4 wherein a 4×SC (four times subcarrier) clock signal from write clock generator 13 is applied to horizontal counter 22a and horizontal write address counter 22c. The horizontal counter 22a repeats every 910 samples which is slaved to the leading edge of each received horizontal sync pulse. The start address decoder 22b detects a "start" signal where the left edge of the normal active picture appears and applies this start signal to counter 22c and to flip-flop 22j. The flip-flop 22j in response to the "start" signal changes state and provides an enable to AND gate 22h. This start signal occurs for the example 9 microseconds after the leading edge of horizontal sync pulses (See FIG. 2). The horizontal write address counter 22c is clocked by the same 4×SC clock pulses to increment the addresses but remains "off" or inhibited until the "start" signal from start address decoder 22b is applied thereto whereupon it begins to count starting from address 0 and is incremented by one with each and every clock pulse during every horizontal line. The flip-flop 22j is reset at the end of each horizontal line by a signal from counter 22a.
Similarly, as illustrated in FIG. 4, the typical synchronizer of FIG. 1 includes a vertical address generator which is set to zero for the example on line 15. A first vertical counter 22d is responsive to the leading edge of the vertical sync from the write clock generator for resetting the counter 22d for counting the incoming horizontal sync pulses from the write clock generator pulses (lines). A line 15 decoder 22e is responsive to the line 15 count from the vertical counter 22d for providing a "start" signal to the vertical address counter or generator 22f to enable vertical addresses starting at 0 for the example on line 15 and to allow the vertical address counter 22f to be incremented by one each and every blanking interval thereafter. The write control signal out of AND gate 22h is enabled by the "start" signal being applied to flip-flop 22g which in turn applies the enable to AND gate 22h. The start address decoder 22b and line 15 decoder therefore detect the picture area to be stored in the memory to provide a "start" signal which enable AND gate 22h to provide a write control pulse to memory and to start incrementing the addresses.
To implement this invention, these processes are modified slightly when writing into the memory but are unaltered for reading from the memory. To cause the picture to be raised by one horizontal line, rather than starting the vertical address at 0 on line 15, it is set to 0 on line 16. To cause the picture to be raised by 10 horizontal lines, the vertical address is set to 0 on line 25. Video that occurred between line 15 and line 25 is automatically deleted. In general, to raise the picture by n lines requires setting the vertical address to 0 on line 15+n. To illustrate how the picture is raised, consider the case of lifting the picture 10 lines. Video from the 25th line is stored in vertical address 0. When reading this video from the memory, it will be displayed on line 15, 10 lines higher up on the output monitor. To accomplish this delay, an alternate line decoder 50 is coupled via a switch 51--switched from the normal "N" position to the "M" or modified position--between the vertical counter 22d and vertical write address generator (a counter) 22f. The alternate line decoder 50 for the above example when switch 51 is in the M position would count to 25 lines rather than 15 lines before applying the "start" signal to the vertical write address 22f and to flip-flop 22g providing an enabling signal to AND gate 22h. The write control signal would thereby be inhibited until line 25. The first 25 lines would be omitted from the memory and the input on line 25 would output on line 10 and the effect would be when read out that the picture would be raised 10 lines. The flip-flop 22g is reset when a whole field of horizontal sync pulses have been applied to vertical counter 22d by a control signal therefrom. To move the picture down requires the modified scheme of setting the addresses to a value greater than 0. For example, to move the picture down 10 horizontal lines would require setting the vertical write address generator or counter 22f to 10 on line 15. This may be provided by vertical address encoder 52 in FIG. 4 with switch 51 in the "N" position. The encoder 52 is normally out of the system with a switch 52a in the R or position to always reset the generator 22f in the "O" address position. When switch 52a is in the encoder 52 position, the preset address of encoder 52 or 10 for the example is applied to write vertical address generator 22f and the picture when read normally moves down 10 lines.
To move the picture to the left on the output monitor involves a similar process to that for raising the picture. For instance, to move the picture to the left by 192 addresses (representing one quarter the width of the picture), the horizontal address counter is set to 0, exactly 192 clock pulses after horizontal blanking has terminated.
To accomplish this delay, an alternate start address decoder 53 is coupled via switch 54--switched from the "N" to the "M" or modified position--between the counter 22a and horizontal write address generator (a counter) 22c. The alternate start address decoder 53 for the above example (to move the picture one-quarter width to the left) would count to 192 clock pulses after horizontal blanking before applying the "start" signal via switch 54 at position M to horizontal write address generator 22c. The horizontal write address generator 22c is inhibited until receipt of the "start" from either decoder 22b or alternate decoder 53. Also, there is no write control pulse from AND gate 22h until there is a receipt of the "start" signal to flip-flop 22j. The first 192 samples of each line would be omitted from the memory with the 192nd sample being at left with horizontal address of "0". It is assumed in the above that the horizontal write address generator 22c is reset to address "0" at the start by a switch 55a being in the R or initial zero address position. To move the picture to the right involves a similar process to that for lowering the picture in that the addresses to the horizontal write address counter 22c are preset by an encoder 55. To move the picture in the example by one-quarter of the raster width to the right would require presetting the horizontal address generator 22c to 191 by encoder 55 via switch 55a in the encoder 55 position (as shown) and switch 54 in the "N" position. At the termination of horizontal blanking, the left edge of the picture is stored with the horizontal address 191. When read out normally the video would appear beginning 192 spaces to the right of the normal left edge.
Obviously, both the vertical and horizontal addresses could be modified simultaneously moving the picture diagonally off the screen.
One of the possible methods that could be used to provide this control over the synchronizer write addresses is to use a joystick calibrated in such a way that an analog output is converted to a digital output of all zeros when the joystick is centered and it is desired that the picture be centered. The output of the joystick circuitry is a two's complement binary code with separate horizontal and vertical data. As the joystick is moved to the right, the digital data is the addresses to which the horizontal address counter is set at the termination of horizontal blanking and the vertical address counter is set on line 15. As the joystick is moved to the left or up, the addresses would go from all zeros to all ones and decrease from these values. The fact that the MSB (most significant bit) of this data has become a 1 is an indication that there needs to be a delay of as many clock pulses, or lines, as the data dictates before the address counters are set to zero. One way of controlling this portion of the circuitry is to set a counter to the value dictated by the joystick data, incrementing the counters on every clock pulse, or line, until said counters overflow, thus indicating the time the address counters are to be set to zero. FIG. 5 is a block diagram of the horizontal portion of a circuit as described above. A potentiometer 75 is used to generate a voltage that indicates where the picture should begin. The arrow indicates the position of the joystick. The analog output of the potentiometer 75 is converted to a digital signal by an analog to digital converter 77 calibrated such that 0 volts in produces 0 code output. As the joystick is moved to the right the LSB's (least significant bits) from the A/D converter 77 are used to preset the write address counter 79 at the terminating edge of horizontal blanking. The MSB bit from converter 77 is a logic zero and this logic zero is applied to terminal 83a of AND gate 83 inhibiting any reset to horizontal write address counter 79. By the inverter 85, a logic 1 or high is at terminal 87a of AND gate 87. A second high or a logic 1 level exists after the terminating edge of horizontal blanking in the input signal from terminal 88. (9μ sec after leading edge of horizontal sync). This causes write address counter 79 to write or load into the memory the incoming video samples beginning with the preset video address. If that address is normally for the 192nd sample, the video when read out is displaced one-quarter of the width of the raster to the right. If the joystick is moved to the left, the MSB becomes a logic 1 causing logic 1 at terminal 83a of AND gate 83. Counter 81 is preset to a value indicated by the LSB's from the A/D converter 77. After the number of counts equals the full count minus the preset count, counter 81 provides a carry to terminal 83b of AND gate 83 causing the write address counter 79 to be reset to 0. Counter 81 begins to count at the termination of the horizontal blanking signal (indicated terminating edge of horizontal blanking) at terminal 88. No signal is provided out of AND gate 87 due to the inhibit low at terminal 87a. The write address counter 79 then starts with address "0" and is incremented by each clock pulse after the predetermined delay provided by counter 81 which is determined by the preset value (LSB value). The system of FIG. 5 could be switched across the counter 22a, decoder 22b and write address 22c in FIG. 4 when it is desired to move the picture either to the right or to the left. The vertical circuitry could be incorporated in a similar manner. In the vertical case, when the potentiometer was moved up and down the MSB would be a logic 1 to be raised and a logic 0 to be lowered. When the picture is to be raised, the time at which video is to appear at the top is preset in the first counter (counter 81 in FIG. 5) and when it is to be lowered, the LSB presets the write address counter so that at the terminating edge of vertical blanking the first line of active video is provided with a preset line address of a line value greater than line 10 for example. Other methods could be used to exert similar control over the write addresses. For example, switches could be used to preset specific codes.
In the above described arrangement it has been assumed that the picture is moved in increments of four samples horizontally (full subcarrier cycles) and two lines vertically. It is recognized that the picture may be moved in half cycle increments horizontally and one line increments vertically if means is provided to invert the chrominance. For example, referring to FIG. 6 between the D/A converter 31 and output video 32 in FIG. 1 may be a chroma inverter 90. The LSB from the A/D converter 77 in FIG. 5 and the like LSB from the vertical A/D converter are applied to an exclusive OR 91. The high at the output of the exclusive OR turns "on" the chroma inverter.
If one input to the exclusive OR 91 is high and other is not--indicating an odd number of pair of samples or half subcarrier cycles shifted and an even number of lines maintained or moved or an odd number of lines moved and an even number of pair of samples shifted or maintained--a signal is provided from the exclusive OR 90 to the chroma inverter 90 located between the D/A converter 31 and output video 32 for inverting the chroma only. It is recognized that in the case of a digital chroma inverter the chroma inverter would be located prior to the D/A converter 31 and may even be prior to the memory 20.
By applying the output from the video synchronizer to a conventional video switcher and generating a key signal in the synchronizer indicating the location of the picture in the raster, the video switcher can be used to provide a background signal over the areas not occupied by the picture from the synchronizer. The background may be, for example, another picture.
This television positioning apparatus may be used with a television picture compressor such as that described by Thomas M. Gurley in copending application filed concurrently herewith entitled "Television Picture Compressor", Ser. No. 862,180. (British Provisional filed Mar. 21, 1977 and given No. 11904/77). Also this may be used with the size altering apparatus of Hurst (cited previously) filed Dec. 27, 1976, U.S. Pat. No. 4,134,128 "Television Picture Size Altering Apparatus". In accordance with the combination of compressor apparatus, the combined apparatus will permit the positioning of the compressed picture in any desired location by adjusting the addresses of the compressed picture as it is stored in the memory. In the case of 1/4 size compression this compressed picture may be moved to any position on or off the raster. Also, four different rasters could be compressed with the addresses from the picture positioning apparatus being such that the four compressed pictures are in the four quadrants of a full raster so that when the whole memory is read they may be displayed simultaneously.
Although the present invention has been described in terms of a composite video signal according to the NTSC television standards, the principles of the invention are equally applicable to other television standards as PAL, PAL-M, and SECAM. These other standards do contain differences from the NTSC system which require modification to the portions of the synchronizer and the compressor. Among these are--the clock frequencies which must be adjusted for differences in subcarrier frequency which determines the number of samples per line, i.e., 4.43 MHz in PAL vs. 3.58 MHz in NTSC system. Similarly, the capacity of the memory in terms of lines stored must be adjusted to accommodate the number of vertical lines in each system, typically, 625 in PAL, 525 in PAL-M and 625 in SECAM. In addition, the memory organization and controlling logic must be adjusted to the individual color signal differences in each system such as eight unique fields in PAL in terms of burst phase sequence against only four unique fields in terms of the NTSC burst phase sequence, while in SECAM the burst frequency in the form of an undeviated subcarrier alternates on each line but is of a different frequency on each line. The horizontal and vertical synchronizing signals of each television system must also be accommodated in generating the write addresses for writing into the memory and generating the read addresses for reading out of the memory.
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Apparatus which when implemented with a television video synchronizer permits the operator to position the synchronized picture at any desired location of the television raster including off the screen. A typical synchronizer includes a memory address generator for providing addresses to the memory for each active picture sample following sync timing and the video signals are stored in a predetermined nonvarying location in such a way that reading the stored video out of the memory reproduces the video signal. The positioning by the apparatus is achieved by modifying the storage addresses so that the relationship between sync timing and picture timing is changed.
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BACKGROUND OF THE INVENTION
[0001] Cold therapy is an established practice used in the medical profession to treat certain limb injuries, such as sprained or strained arm or leg muscles or injuries to joints. Generally, these types of injuries should be chilled to slow blood flow, which reduces swelling, pain, and further damage. Cold therapy is also an established practice used to treat migraine and other types of headaches. A typical course of cold therapy treatment is to apply ice for a specified period to the injured region of a limb, the neck, face, or head. Alternatively, a pack or bag containing a chemical agent that reacts (endothermically) to produce cold may be applied to the injured region, the neck, face, or head.
[0002] A number of devices that use endothermic reactions for cooling body parts are known. For example, U.S. Pat. No. 4,986,076 to Kirk et al. and U.S. Pat. No. 2,898,744 to Robbins both disclose a flexible, plastic cooling bag sealed along its edges. The cooling bag is separated by a frangible barrier into two portions: a freezing chemical mixture (salt) portion and a liquid (water) portion. A cooling reaction is activated by squeezing or applying pressure to the bag, which ruptures the frangible barrier and thus allows the salt and liquid portions to mix. The resulting chemical mixture causes an endothermic reaction, which produces a cooling effect. The cooled bag is applied to a body part.
[0003] A concern with such endothermic cold packs is that the solution that is formed ends up at the bottom (i.e., the lowest point) of the enclosure. The localization of the solution within the enclosure results in temperature differences within the cold pack. The temperature differences that are generated within the cold pack cause the cold pack to cool various sections of an area at differing rates.
[0004] Accordingly, there is a need for a cold pack that uniformly cools an area of the body. The cold pack should also be readily portable and adaptable for various needs of users.
SUMMARY OF THE INVENTION
[0005] The present inventors undertook intensive research and development efforts concerning improving instant cold therapy. The present invention is directed in part to a cold pack including an enclosure, a solute within the enclosure, a liquid within the enclosure, and a membrane segregating the liquid from the solute. Further, rupturing the membrane mixes the liquid with the solute to produce an endothermic solution within the enclosure. In addition, the enclosure includes a first compartment, a second compartment, and a connection between the first compartment and the second compartment. The connection is adapted to pass the endothermic solution between the first and the second compartment.
[0006] Another aspect of the present invention is directed to a cold pack including an enclosure, a solute within the enclosure, a liquid within the enclosure, and a membrane segregating the liquid from the solute. Further, rupturing the membrane mixes the liquid with the solute to produce an endothermic solution within the enclosure. In addition, the enclosure includes a first compartment, a second compartment, and a connection between the first compartment and the second compartment. The connection is adapted to pass the endothermic solution between the first and the second compartment. Further, a force other than gravity is needed for the endothermic solution to pass through the connection between the first compartment and the second compartment. Additionally, the cold pack includes a mechanism for temporarily blocking the connection between the first compartment and the second compartment to prevent the endothermic solution from passing between the first compartment and the second compartment.
[0007] A third aspect of the present invention is directed to a cold pack including an enclosure, a solute within the enclosure, a liquid within the enclosure, and a membrane segregating the liquid from the solute. The liquid may be water. The solute may be ammonium nitrate, and the membrane may be polyethylene. Further, rupturing the membrane mixes the liquid with the solute to produce an endothermic solution within the enclosure. In addition, the enclosure includes a first compartment, a second compartment, and a connection between the first compartment and the second compartment. The connection is adapted to pass the endothermic solution between the first and the second compartment.
BRIEF DESCRIPTION OF THE DRAWINGS
[0008] The present invention will be more fully understood, and further features will become apparent, when reference is made to the following detailed description and the accompanying drawings. The drawings are merely representative and are not intended to limit the scope of the claims. Like parts depicted in the drawings are referred to by the same reference numerals.
[0009] FIG. 1 illustrates a schematic section view of a cold pack.
[0010] FIG. 2 illustrates a schematic section view of the cold pack shown in FIG. 1 with a membrane ruptured within the cold pack to produce an endothermic solution within the cold pack.
[0011] FIG. 3 illustrates a schematic section view of another cold pack.
[0012] FIG. 4 illustrates a schematic section view of the cold pack shown in FIG. 3 with a membrane ruptured within the cold pack to produce an endothermic solution within the cold pack.
[0013] FIG. 5A illustrates a plan view of yet another cold pack with multiple compartments.
[0014] FIG. 5B illustrates a plan view of the cold pack shown in FIG. 5A in a first orientation with a membrane ruptured within the cold pack to produce an endothermic solution where the endothermic solution is distributed in one compartment within the cold pack.
[0015] FIG. 5C illustrates a plan view of the cold pack shown in FIG. 5B in a second orientation with a membrane ruptured within the cold pack to produce an endothermic solution.
[0016] FIG. 5D illustrates a plan view of the cold pack shown in FIG. 5A in a first orientation with a membrane ruptured within the cold pack to produce an endothermic solution where the endothermic solution is distributed in more than one compartment within the cold pack.
[0017] FIGS. 6A-6D illustrate several different cold packs with enclosures having compartments and connections between the compartments.
DETAILED DESCRIPTION OF THE INVENTION
[0018] In the following detailed description, reference is made to the accompanying drawings which show specific embodiments in which the invention may be practiced. These embodiments are described in sufficient detail to enable those skilled in the art to practice the invention. It is to be understood that other embodiments may be utilized and structural changes made, such that the following detailed description is not to be taken in a limiting sense.
[0019] FIGS. 1 and 2 illustrate a cold pack 10 . The cold pack 10 includes an enclosure 11 with a solute 12 and a liquid 14 sealed inside the enclosure 11 . The solute 12 and the liquid 14 are segregated within the enclosure 11 by a membrane 16 (see FIG. 1 ). Rupturing the membrane 16 , for example by applying pressure to the enclosure 11 , mixes the liquid 14 (e.g., water) with the solute 12 to produce an endothermic solution 18 within the enclosure 11 (see FIG. 2 ). Substantially all of the solute 12 rapidly dissolves within the liquid 14 such that the cold pack 10 quickly reaches its cooling temperature.
[0020] Cold pack 10 may also include an insulation layer 19 that insulates a portion of the enclosure 11 from the surrounding environment. It should be noted that insulation layer 19 may have any size or shape and may be in or on the enclosure 11 . Insulation layer 19 should be positioned on a side of enclosure 11 that is opposite to the side of enclosure 11 which is to be located on, or near, the body. The insulation layer 19 then serves to reduce warming of the cold pack 10 by the ambient environment without inhibiting heat transfer from the body to the cold pack 10 .
[0021] Membrane 16 may be polyethylene (among other materials). In addition, any conventional solutes may be used to induce an endothermic reaction within cold pack 10 . One example solute includes ammonium nitrate. The rate at which the solute dissolves into the liquid, and thus the rate of cooling, may be affected by the particle size of the solute. For example, if a rapid dissolution is desired, the pieces that form the solute 12 may be between about 0.001 and 0.025 inches, although it should be noted that smaller pieces may be used and some small minority of pieces may be larger than 0.025 inches.
[0022] FIGS. 3 and 4 illustrate a cold pack 10 . The cold pack 10 includes an enclosure 11 and a liquid 14 and a solute 12 sealed inside the enclosure 11 . The solute 12 and the liquid 14 (e.g., water) are segregated within the enclosure 11 by a membrane 16 .
[0023] The cold pack 10 further includes an absorbent core, such as absorbent layer 27 , within the enclosure 11 (see FIG. 3 ). The absorbent layer 17 retains an endothermic solution 18 that is formed within the enclosure 11 by rupturing the membrane 16 (see FIG. 4 ). Once the solute 12 and the liquid 14 are mixed to form the endothermic solution 18 , the absorbent layer 17 spreads the endothermic solution 18 throughout the enclosure 11 such that the cold pack 10 uniformly cools an injured portion of a body when the cold pack 10 is positioned on, or near, the body.
[0024] The membrane 16 may also isolate the absorbent layer 17 from the solute 12 and/or the liquid 14 until the membrane 16 is ruptured to mix the solute 12 and the liquid 14 . In some sample forms, the solute 12 may be interspersed with the absorbent layer 17 before membrane 16 is ruptured. The absorbent core may take forms other than absorbent layer 17 and may be pulp fiber (among other materials).
[0025] It should be noted that in the example cold pack 10 illustrated in FIGS. 3 and 4 , solute 12 may be in pellet or powder form. In addition, cold pack 10 may include an insulation layer 19 which is similar to insulation layer 19 described above with regard to FIGS. 1 and 2 .
[0026] In some example embodiments, the solute 12 may be integral with the absorbent layer 17 as opposed to being initially isolated from the absorbent layer 17 . Although not specifically illustrated, these types of example embodiments may include an enclosure 11 and a membrane 16 that initially segregates a liquid 14 from a solute-filled absorbent layer 17 within the enclosure 11 . Combining the solute 12 with the absorbent layer may simplify fabrication of such cold packs.
[0027] FIGS. 5A-5D illustrate a plan view of yet another cold pack 10 with multiple compartments 21 ′, 21 ″, 21 ′″ within the enclosure 11 . The enclosure 11 also includes connections 23 ′, 23 ″ that are adapted to pass material between the compartments such as liquid 14 , solute 12 , or endothermic solution 18 . The cold pack 10 illustrated in FIGS. 5A-5D includes a first compartment 21 ′, a second compartment 21 ″, and a third compartment 21 ′″. This cold pack 10 may be suitable for treating the forehead and temples. The first compartment 21 ′ may generally correspond with the area of the cold pack 10 that contacts the forehead. The second compartment 21 ″ and the third compartment 21 ′″ may generally correspond with areas of the cold pack 10 that contact the temples.
[0028] Sufferers of headaches, and in particular migraine headaches, may find it comforting to lie down, or be in a reclined position while applying cooling to their heads. Further, sufferers of headaches may also desire a uniform distribution across the temple and forehead area. The compartments 21 ′, 21 ″, 21 ′″, and connections 23 ′, 23 ″ allow for the endothermic solution 18 to move around the enclosure 11 under certain situations, and prevent movement of the endothermic solution 18 around the enclosure 11 under other situations. Specifically, with the cold pack 10 in a first orientation in relation to gravity as shown in FIGS. 5A , 5 B, and 5 D with indicator arrow 25 pointed in the upward direction, the connections 23 ′, 23 ″ are positioned near top of the enclosure 11 , such that the endothermic solution 18 does not pass through the connections 23 ′, 23 ″. However, with the cold pack 10 in a second orientation in relation to gravity as show in FIG. 5C with indicator arrow 25 pointed downward, the connection 23 ′, 23 ″ are positioned near the bottom of the enclosure 11 , such that the endothermic solution 18 does pass between the compartments 21 ′, 21 ″, and 21 ′″. A user may distribute the endothermic solution 18 between the first, second, and third compartments 21 ′, 21 ″, 21 ′″ in a manner that best suits their needs. For example, one sufferer may chose to have equal amounts of endothermic solution 18 in each of the compartments 21 ′, 21 ″, 21 ′″, while another sufferer may choose to have a disproportionate amount of endothermic solution in the first (center) compartment 21 ′. Regardless, the compartments 21 ′, 21 ″, 21 ′″ and connections 23 ′, 23 ″ allow the sufferer the ability to counteract the natural distribution of liquid that gravity would affect on an open enclosure.
[0029] The cold pack 10 is illustrated in FIGS. 5A-5D in four distinct configurations. In the first configuration, illustrated in FIG. 5A , the membrane 16 is intact, and the liquid 14 and the solute 12 are separate. In the second configuration, illustrated in FIG. 5b , the membrane 16 has been ruptured and the solute 12 and the liquid 14 have formed an endothermic solution 18 . Further in this second configuration, the endothermic solution 18 is contained exclusively within the first compartment 21 ′, and endothermic solution does not pass through the connection 23 ′, 23 ″. In the third configuration, illustrated in FIG. 5C , the cold pack has been oriented such that the endothermic solution 18 has passed through the connection 23 ′, 23 ″ into the second compartment 21 ″, and the third compartment 21 ′″. As illustrated in FIG. 5C , the endothermic solution 18 may be distributed proportionately in each compartment 21 ′, 21 ″, 21 ′″. In the fourth configuration, illustrated in FIG. 5D , the endothermic solution is distributed disproportionately in the compartment 21 ′, 21 ″, 21 ′″, specifically a proportionally larger amount of endothermic solution 18 is located in the second compartment 21 ″, and the third compartment 21 ′″ than is located in the first compartment 21 ′. Depending on the specific design and use of the cold pack 10 , a user may choose to locate various amounts of endothermic solution 18 in the compartments 21 ′, 21 ″, 21 ′″.
[0030] Endothermic solution may pass between the compartments 21 ′, 21 ″, 21 ′″ under the force of gravity. Alternatively, the connection 23 ′, 23 ″ may be designed such that a force other than gravity is needed for the endothermic solution 18 to pass through the connection between the compartments 21 ′, 21 ″, 21 ′″. This force may be pressure applied to the exterior of the enclosure 11 increasing the pressure of the endothermic solution 18 in one of the compartments 21 ′, 21 ″, 21 ′″ in relation to another compartment 21 ′, 21 ″, 21 ′″.
[0031] The compartments 21 ′, 21 ″, 21 ′″ may be formed in any suitable manner. For example, the enclosure 11 may be formed from two planar sheets of material joined together along the periphery of the two sheets. The compartments 21 ′, 21 ″, 21 ′″ may be formed by joining portions of the two sheets forming the compartments 21 ′, 21 ″, 21 ′″. The sheets may be joined using thermal, ultrasonic, or adhesive bonding. Alternatively, two or three compartments 21 ′, 21 ″, 21 ′″ may be formed separately, and then joined with connections. For example, the connections may be straws or tubes which connect the compartments 21 ′, 21 ″, 21 ′″.
[0032] The connections 23 ′, 23 ″ may be adapted to remain open at all times. Alternatively, the connections 23 ′, 23 ″ may be adapted to be blocked either temporarily or permanently. For example, the material which surrounds the connection 23 ′, 23 ″ may be elastic such that by applying tension the connection 23 ′, 23 ″ opens and allows endothermic solution 18 to pass between the compartments 21 ′, 21 ″, 21 ′″. Further, upon release of the tension, the connections 23 ′, 23 ″ may become blocked, preventing the endothermic solution 18 from passing between the compartments 21 ′, 21 ″, 21 ′″. Many suitable devices may be used to temporarily block the connection 23 ′, 23 ″, for example, a valve, a clip, a tie, a plug, or a zipper seam may be used. As used herein, the term “zipper seam” refers to self-mating rib and flange seams such as are commonly used with sandwich bags. A suitable zipper seam is described in U.S. Pat. No. 6,544,604 issued Apr. 15, 2003 to Galkiewicz et al. Many suitable devices may be used to permanently block the connection 23 ′, 23 ′″; for example, an adhesive, a thermal seal, or a solvent weld.
[0033] Depending on the specific design and desired final use of the cold pack 10 , the solute 12 and the liquid 14 may be located anywhere within the enclosure 11 . For example the solute 12 may be located in the first compartment 21 ′ and the liquid 14 may be located in the second compartment 21 ″. Alternatively the solute 12 may be located in the first compartment 21 ′ and the liquid 14 may also be located in the first compartment 21 ′.
[0034] The first compartment 21 ′ and the second compartment 21 ″ may include absorbent core 17 adapted to retain the endothermic solution 18 . For example the first compartment 21 ′ may include an absorbent core 17 while the second compartment 21 ″ may not include an absorbent core 17 . This may be advantageous where the first compartment 21 ′ is adapted to be used such that it is elevated relative to the second compartment 21 ″ during use, for example where the first compartment 21 ′ is adapted to be used on the forehead and the second compartment 21 ″ is adapted to be used on a temple when the user is in a reclined position. In this configuration, the second compartment 21 ″ may or may not include a second absorbent core.
[0035] FIGS. 6A-6D illustrate several different cold packs with enclosures having compartments and connections between the compartments. FIG. 6A illustrates a cold pack 10 having five compartments 21 , and four connections 23 between the compartments 21 . As illustrated in FIG. 6A , the connections 23 are located at the top and bottom of the enclosure 11 , alternating top to bottom from left to right. This cold pack 10 may be suitable for use in cooling an ankle or a neck.
[0036] FIG. 6B illustrates a cold pack 10 having two compartments 21 and one connection 23 between the compartments 21 . As illustrated in FIG. 6B , the compartments 21 are located at opposite ends of a relatively long connection 23 . This cold pack 10 may be suitable for use in cooling the left and right temple, or the left and right side of a knee, ankle, elbow, or shoulder.
[0037] FIG. 6C illustrates a cold pack 10 having seven compartments 21 and six connections 23 between the compartments 21 . As illustrated in FIG. 6C , the cold pack 10 is designed and shaped to cover the eyes of a user, with a notch for the nose. The compartments 21 and connections 23 are designed such that a user may distribute endothermic solution such that a uniform cooling may occur around the eyes.
[0038] FIG. 6D illustrates a cold pack 10 having six compartments 21 and six connections 23 between the compartments 21 . As illustrated in FIG. 6C , cold pack 10 is generally circular in shape and the compartments 21 have the shape of a sector of a circle of approximately 60 degrees. The connection 23 is located at the center of the circle. This cold pack 10 may be suitable for use in cooling the knee, elbow, shoulder, or ankle.
[0039] In alternative forms, the cold pack 10 may include numerous additional features. For example the cold pack 10 may include outer covers made from a wide variety of materials, including, for example, woven fabrics and nonwoven fabrics or webs. Nonwoven materials suitable for use with the present invention include, for example, a multilayer laminate such as a spunbond/meltblown/spunbond (“SMS”) material. An example of such a fabric is disclosed in U.S. Pat. No. 4,041,203 and is hereby incorporated by reference. Additional features may include material adapted to extending the cooling duration of the cold pack 10 , for example as disclosed in U.S. Pat. No. 6,881,219 and hereby incorporated by reference.
[0040] In alternative forms, a release layer (not shown) may be detachably mounted to the cold pack using an adhesive. The release layer may be removed from the cold pack leaving only the adhesive on the cold pack. The remaining adhesive provides a means for directly or indirectly securing the cold pack to a body, flexible wrap, and/or other device.
[0041] A method of cooling a portion of a body is described herein with reference to FIGS. 5A-5D and FIGS. 6A-6D . In one form, the method includes segregating a solute 12 from a liquid 14 where the solute 12 and the liquid 14 are inside of a cold pack 10 ( FIGS. 5A , 6 A- 6 D). The method further includes mixing the solute 12 with the liquid 14 to form an endothermic solution 18 within the cold pack 10 , distributing the endothermic solution 18 though connections 23 within the cold pack 10 , and applying the cold pack 10 to the portion of the body. In some sample forms of the method, mixing the solute 12 and the liquid 14 to form an endothermic solution 18 includes rupturing a membrane 16 that segregates the solute 12 from the liquid 14 within the cold pack 10 .
[0042] In some sample forms of the method, distributing the endothermic solution 18 throughout the cold pack 10 includes retaining the endothermic solution 18 within an absorbent core, such as absorbent layer 27 . In some alternative forms, the method includes mixing the solute 12 and the liquid 14 within the absorbent layer 17 . It should also be noted that the solute 12 may be in pellet form or powder form.
[0043] The size and shapes of the cold packs described herein will depend on the applications where the cold packs will be used (among other factors). In addition, the membranes within the enclosures may have any size, number, arrangement, and configuration as long as the membrane (i) segregates the solute from the liquid; and (ii) is capable of being ruptured so that the solute can be mixed with the liquid to form an endothermic solution.
[0044] The operations discussed above with respect to the described methods may be performed in a different order from those described herein. It should be noted that attaching a cold pack to a body includes attaching the cold pack directly or indirectly to the body. In addition, FIGS. 1-6D are representational and are not necessarily drawn to scale. Certain proportions thereof may be exaggerated, while others may be minimized.
[0045] While the invention has been described in detail with respect to the specific aspects thereof, it will be appreciated that those skilled in the art, upon attaining an understanding of the foregoing, may readily conceive of alterations to, variations of, and equivalents to these aspects which fall within the spirit and scope of the present invention, which should be assessed accordingly to those of the appended claims.
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Cold therapy is an established practice used in the medical profession to treat certain limb injuries, such as sprained or strained arm or leg muscles or injuries to joints. Generally, these types of injuries should be chilled to slow blood flow, which reduces swelling, pain, and further damage. Cold therapy is also an established practice used to treat migraine and other types of headaches. A typical course of cold therapy treatment is to apply ice for a specified period to the injured region of a limb, the neck, face, or head. Alternatively, a pack or bag containing a chemical agent that reacts (endothermically) to produce cold may be applied to the injured region, the neck, face, or head.
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RELATED APPLICATIONS
[0001] This application is a continuation, under 35 U.S.C. § 120, of International Patent Application No. PCT/AU03/00755, filed on Jun. 17, 2003 under the Patent Cooperation Treaty (PCT), which was published by the International Bureau in English on Dec. 24, 2003, which designates the United States and claims the benefit of Australian Provisional Patent Application No. PS 3006, filed Jun. 18, 2002.
FIELD OF THE INVENTION
[0002] The present invention relates to membrane filtration systems and in particular to system using a plurality of porous hollow fibre membranes wherein loss of membrane integrity can lead to degradation of filtration performance.
BACKGROUND OF THE INVENTION
[0003] Consider a typical hollow fibre membrane module as shown in FIG. 1 . The module consists of plurality of hollow fibre membranes 5 potted at least at one end into a pot 6 having a length L. In order to calculate the flow from individual fibres the TMP (Transmembrane pressure P 1 -P 2 ) is considered as acting across a total module resistance R to give a flow Q:
[0000] TMP/RαQ (at constant temperature)
[0000] Now in this typical model we can break the resistance down into:
[0000]
R=R
m
+R
pot
[0000] and Q i αTMP/(R m +R pot )
[0000] where Q i is the flow emerging from the top of the intact fibre, R m is the module resistance and R pot is the resistance across the pot.
[0004] We can assume R m is constant—a sort of average—though it will vary down the length of the fibre.
[0005] Now taking the case where a fibre is broken at the top pot (a worst case for filtrate bypass). In this case:
[0000] R m =0
[0000] and Q b αTMP/R pot
[0000] where Q b is the flow of filtrate emerging from the top of the broken fibre.
[0006] The ratio of the flow down a broken fibre to the flow down an intact fibre is calculated as follows:
[0000]
=
Q
b
/
Q
i
=
(
R
m
+
R
pot
)
/
R
pot
=
1
+
R
m
/
R
pot
[0007] In the normal case R m >>R pot —typically 20. Thus it can be seen a broken fibre allows a significant amount of feed to contaminate the filtrate and thus degrade filtration performance. Additionally, increasing the internal diameter of the fibre makes the problem massively worse as typically R pot αL/d 4 , where d is the diameter of the lumen and L is the length of the pot.
[0008] Accordingly, it is desirable to reduce the flow of filtrate from a broken fibre. Take the case where we increase R pot (for instance by increasing L or reducing d). The limit of Q b /Q i tends to 1. This is a highly desirable result. But increasing the length of the pot is undesirable in other ways—it increases the length of the module and the expense of the module and process. The other option is to reducing the internal diameter of the fibre in the pot.
SUMMARY OF THE INVENTION
[0009] It is an object of the present invention to overcome or at least ameliorate the problems of the prior art associated with integrity loss in hollow fibre membrane filtration systems or at least provide a useful alternative.
[0010] According to one aspect, the present invention provides a method of reducing the effect of integrity loss in a hollow fibre membrane module, said module including a plurality of hollow fibre membranes, at least one end of said fibre membranes being supported in a pot, the method including the step of increasing flow resistance of the liquid through the lumen of the fibre membrane in the region of the pot.
[0011] Preferably, the step of increasing the flow resistance is produced by reducing the inner cross-sectional area of the fibre lumen in the region of the pot. For preference, the step of increasing the flow resistance is produced by placing a porous layer in the flow path of the fibre lumen in the region of the pot.
[0012] According to a second aspect, the present invention provides a hollow fibre membrane module including a plurality of hollow fibre membranes supported at least at one end in a pot and having flow restriction means in the lumens of said fibre membranes in the region of said pot.
[0013] Preferably, the flow restriction means comprise means for reducing the inner cross-sectional area of the fibre lumen in the region of the pot.
BRIEF DESCRIPTION OF THE DRAWINGS
[0014] Preferred embodiments of the invention will now be described, by way of example only, with reference to the accompanying drawings in which:
[0015] FIG. 1 is a schematic sectional elevation of a typical hollow fibre membrane module with an intact and broken fibre;
[0016] FIG. 2 is a similar view to FIG. 1 with the addition of a porous layer to the pot surface;
[0017] FIGS. 3A to 3K show enlarged schematic cross-sectional elevations of various embodiments of the invention; and
[0018] FIG. 4 shows the results of a test performed on two modules to illustrate the operation of the invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0019] Referring to FIG. 2 of the drawings, one preferred embodiment of the invention is illustrated. A sinter or porous layer 10 is placed on top of the pot 6 to provide a further series resistance R pot2 to the pot i.e.
[0000]
R
pot
=R
pot1
+R
pot2
[0020] An appropriate sinter 10 may have openings of microns in dimension and only be a few millimetres thick. This method may reduce the Q b /Q i by a factor of 10.
[0021] Such an arrangement provides added benefits when used for membrane filter systems in a bio-reactor. The high solids feed in bio reactors leads to the sludge actually plugging the filter and self sealing the broken fibre totally.
[0022] The may be extended to the general case by replacing the sinter with a membrane with the same pore size as the hollow fibre membrane and enabling achievement of this self plugging capability even with low solids feeds.
[0023] It will be apparent the extra resistance of the sinter or membrane 10 will require an extra pressure to maintain the module filtrate flow, however, this is only an operating cost not a membrane process operating efficiency as it is operating over the pot assembly, not across the compressible dirt layer on the membrane.
[0024] Fouling of this membrane sinter can be reduced by a regular chemical cleaning backwash with chlorine or other suitable cleaners.
[0025] The membrane/sinter 10 is desirably in intimate contact with the pot 6 to prevent sideways flow of filtrate/feed bypass. This may also be achieved with a replaceable sinter/membrane element.
[0026] A highly asymmetric membrane 10 with the large pore side contacting the pot 6 (so in normal filtrate flow the filtrate flows in the direction of reducing pore size) is desirable.
[0027] As shown in FIGS. 3B-3K a variety of methods may be used to increase the pot flow resistance.
[0028] Referring to FIG. 3A a normal pot 6 without modification is shown. FIG. 3B shows an increased length pot 6 which, while increasing pot flow resistance, has other disadvantages.
[0029] FIG. 3C illustrates providing the fibre 5 with a non porous coating 7 adjacent the interface 8 between the fibre 5 and the pot 6 . This serves to increase pot flow resistance while also moving the fibre failure point away from the fibre-pot interface.
[0030] FIGS. 3D and 3E show a further method of reducing flow by reducing the inner diameter of the fibre lumen 8 using a layer of material 9 applied to part or whole of the inner surface 11 of the fibre lumen 8 in the region encompassed by the pot 6 .
[0031] One method of providing such a layer 9 is to coat the inside of the lumen 8 near the end of the pot 6 with a thin layer of material that effectively reduces the diameter of the fibre lumen 8 at this point. This can be achieved by drawing up a material such as epoxy into the end of the fibre lumen 8 and then allowing it to run out again before it has time to set, leaving behind a thin coating 9 on the inner fibre lumen wall 12 that can then set over time.
[0032] The embodiment shown in FIG. 3F illustrates smearing the surface of the pot with a suitable grout material 13 to reduce the diameter of the fibre lumen 8 adjacent its opening 14 from the pot 6 .
[0033] FIG. 3G shows the insertion of hollow annulus 15 , for example, a hollow pin, into the end of the fibre lumen 8 in the region of the pot 6 to reduce the cross-sectional area of the lumen 8 in the region of the pot 6 .
[0034] FIG. 3H shows the use of a porous layer of material 10 across the lumen opening 14 as also shown in the embodiment of FIG. 2 .
[0035] FIG. 3I shows an embodiment where a porous material is forced into the lumen opening 14 to form a plug 16 . This can be achieved by smearing a porous grout across and into the fibre lumen opening 14 . Again this serves to reduce the flow resistance of the fibre lumen in the region of the pot 6 .
[0036] FIG. 3J illustrates an embodiment of the invention where the fibre lumen 8 is narrowed within the region of the pot 6 by causing the potting material to swell or constricting the end of the fibre.
[0037] FIG. 3K shows an embodiment where the fibre lumen end is narrowed prior to potting.
[0038] FIG. 4 shows the results of a test performed on two modules to illustrate the operation of the invention. Two modules A and B were used in the test. For each module one hollow fibre membrane was potted. The end of the fibre which was not in the pot, was sealed. A stainless steel mesh was glued on the top of one of the pots in a way that prevented sideways flow of feed bypass during filtration in a similar manner to the embodiments shown in FIGS. 2 and 3H . The mesh had openings of 51 microns and was 56 microns thick. The characteristics of both of the modules are shown in Table 1.
[0000]
TABLE 1
Characteristics of the modules
Length of the pot L p
Length of the
Name
(mm)
fibre L f (mm)
Other characteristics
Module A
56
202
none
Module B
53
205
Mesh glued on the pot
[0039] Firstly, feed water was filtered through module A for 35 minutes. During this filtration, the transmembrane pressure (TMP) was measured. Then the fibre of module A was cut as close to the pot as possible and module A filtered the same feed water for a further 35 minutes. During this filtration, the transmembrane pressure (TMP) was measured. The same test was repeated with the module B using the same feed water.
[0040] The graph shown in FIG. 4 compares the TMP of the modules A and B during the two filtrations before and after the fibre was cut. The first part of the graph shows that the two curves are very similar. In particular, it shows that TMP of both modules increased at the same rate. Fibres of the modules were fouled at a similar rate. The small difference in TMP between the two modules is due to the mesh on module B which adds a small extra resistance to flow. The second part of the graph after the fibre of modules was cut shows that TMP of module A and B developed in a highly different way. The TMP of module A remained low and level whereas the TMP of module B increased sharply showing that the mesh was blocked by the feed contaminants.
[0041] This test clearly shows the efficiency of a mesh as far as reduction of integrity loss is concerned. Due to the addition of the mesh to the module, the cut fibre quickly sealed itself, preventing the feed from contaminating the filtrate.
[0042] It will be apparent to those skilled in the art that a wide variety and number of techniques can be used to reduce the flow within the fibre lumen in the region of the pot and that such techniques fall within the scope of the invention described. It will also be appreciated that further embodiments and exemplifications of the invention are possible without departing from the spirit or scope of the invention described.
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A method and apparatus for reducing the effect of integrity loss in a hollow fibre membrane module, said module including a plurality of hollow fibre membranes ( 5 ), at least one end of the fibre membranes ( 5 ) being supported in a pot ( 6 ), the method including the step of increasing flow resistance of the liquid through the lumen ( 8 ) of the fibre membrane ( 5 ) in the region of the pot ( 6 ).
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FIELD OF THE INVENTION
This invention relates to the recycling of asphalt materials and more particularly, to the recycling of scrap asphalt concrete which has been recovered, then crushed and mixed with hydraulic cement and utilized to provide an asphalt concrete paving structure.
BACKGROUND OF THE INVENTION
Asphalt may be characterized as an organic cementitious material in which the predominant constituents are bitumens as they may occur in nature or as they may be produced as byproducts in petroleum refining operations. Asphalt materials and the standards to be applied in asphalt paving applications are described in the booklet entitled SUPERPAVE Series No. 1 (SP-1) “Performance Graded Asphalt Binder Specification and Testing,” 3 rd Edition, 2003, published by the Asphalt Institute, Research Park Drive, P.O. Box 14052, Lexington, Ky. 40512-4052. Asphalts can generally be characterized as a dark brown or black solid or highly viscous liquid which incorporates a mixture of paraffinic and aromatic compounds and various heterocyclic compounds containing Group 15 or 16 elements (new notation), such as nitrogen, oxygen or sulfur. Typical analyses of asphalt cements employed in forming asphalt concretes are disclosed in the aforementioned SUPERPAVE booklet in Chapter 1 under the subheading “Chemical Composition of Asphalt” found on pages 3-6.
Asphalt paving materials based upon asphalt binder or “cements” and aggregate mixtures, commonly referred to as “asphalt concrete” or macadam, are used in many applications such as in the resurfacing of streets, parking lots and the like which are subject to vehicular traffic. While the asphalt may be used alone, such as where it applied as a relatively thin film on existing paving structure, it is usually used in an asphalt concrete in which the asphaltic base material is mixed with a aggregate in an amount substantially in excess of the amount of the asphalt. Typically, an asphalt concrete may contain about 5-20 wt. % asphalt binder with the remainder being the aggregate material. The asphalt binder material may be modified through the use of polymers to produce polymer-modified asphalts and may further incorporate additional additives such as ground rubber, also called crumb rubber. It may also incorporate elastomeric-type polymers, such as polybutadiene, polyisoprene or polyisobutene rubber, polymethacrylate and ethylene propylene diene terpolymer. As described in the aforementioned SUPERPAVE booklet under the subheading “Aging Behavior,” asphalt can degenerate because of oxidation of its component compounds and devolatilization, in which volatile components gradually evolve from the asphalt. Thus, the asphalt paving materials, when first laid down, tend to be in a relatively resilient state in which they are impacted, but not fractured, under the stress imposed by vehicular traffic. With the passage of time and the release of the more volatile components from the asphalt, as well as oxidative hardening, the asphalt tends to age and become brittle. Thus, particularly in the case of heavily traveled paving surfaces, the asphalt concrete becomes less resilient and as the surfaces lose their resiliency, the pavement fractures under applied stress and the asphalt concrete becomes heavily fractured. The fractures occur initially at the surface where the asphalt tends to be most heavily devolatized and oxidized. Thus the pavement near the surface can be characterized as “dead” asphalt, while the lower portion of the asphalt has a higher volatiles content and thus retains some resiliency.
Once the asphalt pavement becomes “dead” where it largely loses its effectiveness as a pavement surface, the pavement can be broken up and removed. Alternatively, the asphalt concrete material can be left in place and treated by the addition of additional material, such as asphalt cement or hydraulic cement, and then recompressed to form a new paving structure. Typically, the new structure would be used as a base and covered with a relatively thin film of asphalt or possibly an asphalt concrete having relatively fine aggregate components.
SUMMARY OF THE INVENTION
In accordance with the present invention, there is provided a method of recycling an asphalt-based material. In carrying out the invention, there is provided a crushed asphalt concrete comprising a friable mixture of asphalt and aggregate particles produced by breaking down a recycled asphalt/aggregate concrete by any suitable technique such as by milling or crushing, or by a combination of such operations. The aggregate particles in the friable mixture include a substantial portion of the surfaces thereof which are substantially free of adhered asphalt material. The crushed asphalt concrete is mixed with a minor amount of hydraulic cement and water to produce a plastic mixture of the crushed asphalt concrete and hydraulic cement in which the crushed asphalt concrete is the predominant component. The plastic mixture is transported to a utilization site such as a building site, road or parking lot and the like, and spread on a substrate surface to provide a layer of asphalt concrete pavement. The term “pavement” is used herein to denote any load bearing pavement structure regardless of the use to which the pavement structure is put. Thus, the term “pavement” denotes foundation slabs such as are use to provide building pads, channel linings in irrigation channels, tarmacs and other surfaces as well as the paving surfaces normally encountered on roadways, bicycle and walk paths, parking lots and the like.
Preferably, the layer of asphalt concrete pavement has a 7-day compressive strength of no more than 1,500 psi and usually no more than 1,000 psi. More specifically, the asphalt concrete pavement exhibits a 7-day compressive strength within the range of 150-800 psi. In the mixture of crushed asphalt concrete and hydraulic cement, the cement is present in an amount within the range of 1-14 wt. % of the crushed asphalt concrete and any added aggregate. Preferably, the hydraulic cement is present in an amount within the range of 2-10 wt. %.
Preferably, the plastic mixture is formed by initially contacting the cement and the crushed asphalt concrete, followed by adding water to the crushed asphalt concrete and the cement. In a preferred embodiment of the invention, this is accomplished by disposing the crushed asphalt concrete on a support surface to provide a relatively thin layer of the crushed asphalt concrete and the hydraulic cement is then added by dispersing the hydraulic cement on the surface of the layered crushed asphalt concrete.
The asphalt in the recycled asphalt concrete preferably has a volatiles content which is no more than 50% of the original volatiles content of asphalt concrete from which the crushed asphalt concrete is derived. Preferably, the asphalt in the crushed asphalt concrete has a volatiles content of no more than 0.1 wt. %. In addition, it is preferred that the plastic mixture be transported to the utilization site and spread on the substrate surface within two hours after mixing of the aggregate cement mixture.
In a further aspect of the invention, there is provided a mixing assembly comprising a moveable conveyor surface which loads to a mixing mill. The crushed asphalt concrete is deposited on the conveyor surface to provide a layer of the crushed asphalt concrete having a depth which is substantially less than the width of the crushed asphalt concrete on the conveyor surface. A minor amount of the hydraulic cement is then dispensed on the layer of crushed asphalt concrete and the crushed concrete and hydraulic cement is conveyed to the mixing mill. Subsequent to the addition of the hydraulic cement and subsequent to or prior to the supply of the hydraulic cement and crushed asphalt concrete into the mixing mill, water is added in an amount effective to produce a plastic mixture. The plastic mixture of crushed asphalt concrete and the hydraulic cement is recovered from the mixing mill and then transferred to a utilization site where it is spread and compacted to provide a layer of asphalt concrete pavement.
In a further embodiment of the invention, an aggregate is added on to the conveyor surface along with the supply of crushed asphalt concrete to the conveyor surface. The additional aggregate is added prior to the addition of the hydraulic cement to the original supply of crushed asphalt concrete on the conveyor surface. In a further aspect of the invention, the crushed asphalt concrete is supplied to the conveyor surface in at least two successive increments.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic side elevational view of a conveyor-mixing system suitable for carrying out the invention.
FIG. 2 is a schematic illustrating another embodiment of a conveyor mixing system for carrying out the invention.
FIG. 3 is a side elevational view of an internal face of a block of cured asphalt concrete paving formed in accordance with the present invention.
DETAILED DESCRIPTION OF THE INVENTION
Asphalt concretes which incorporate an aggregate component and an asphalt binder component are widely used as paving materials on surfaces such as roadways and parking lots. Asphalt concrete typically is applied by forming a mixture of the aggregate particles with molten asphalt binder material which is then applied to the roadway or other surface, where it hardens as the asphalt cools. Typically, the molten asphalt concrete is prepared at a batching plant by mixing the asphalt binder and aggregate and then transferred by truck to the road site where the molten asphalt concrete is applied through a slip form or other suitable means, and then as it is cooled, it is rolled to provide the final pavement.
Asphaltic concrete, comprising asphalt binder and aggregate, as well as asphalt compositions for resurfacing asphaltic concrete, should exhibit desirable mechanical properties including characteristics involving desirable levels of elasticity and plasticity. As noted previously, various polymers can be added to asphalts to improve physical and mechanical performance properties. Polymer-modified asphalts are routinely used in the construction of roads and other paving surfaces. Conventional asphalts often do not retain sufficient elasticity in use and, also, exhibit a plasticity range that may be too narrow for use in some road construction applications. The characteristics of road asphalt concretes and the like can be improved by the incorporation of elastomeric-type polymers such as those disclosed previously as well as other polymers such as ethylene/vinyl acetate copolymer, polyacrylate, polymethacrylate, polychloroprene, polynorbornene, and random or block copolymers of styrene and a conjugated diene. Such modified asphalts commonly are referred to as bitumen/polymer binders or asphalt/polymer mixes. Modified asphalt binders and asphalt emulsions typically are produced utilizing styrene/butadiene based polymers, and typically have raised softening point, increased viscoelasticity, enhanced strain recovery, and improved low temperature strain characteristics. The polymer may be added along with a sulfur-based reactant that promotes cross-linking of the polymer molecules to provide the desired asphalt properties.
As the polymer concentration is increased, the working viscosity of the asphalt mix may become prohibitively high and separation of the asphalt and polymer may occur. The high viscosities experienced at increased polymer concentrations may make emulsification of the asphalt difficult. Asphalt-water emulsions are desirable in many applications because the emulsion may be applied at lower temperatures than hot-mix asphalts since the water acts as a carrier for the asphalt particles. For example, hot-mix asphalts, mixes of asphalt, aggregate, and a single polymer, commonly are applied at a temperatures within the range of about 250° F. to 350° F. to achieve the requisite plasticity for application. In contrast, an asphalt emulsion typically may be applied at lower temperatures within the range of about 35° F. to 85° F. with the same working characteristics. Emulsified asphalt products are generally used to reduce the release of environmentally-harmful volatile organic compounds often associated with asphalts diluted with light carrier solvents such as diesel fuel, naphtha, and the like. Emulsification basically requires that the asphalt and any desired performance-enhancing additives be combined with an emulsifying agent in an emulsification mill along with about 20 to 40 percent by weight of water. However, high polymer loading in asphalt produces high viscosities and melting points, making emulsification of the polymer-asphalt composition difficult.
Regardless of the nature of the binder in an asphalt concrete, the asphalt concrete, when it is first laid down and allowed to cure, forms a highly resilient paving surface which is not easily ruptured by the compressive stresses imposed by vehicular traffic. At this stage of its use, asphalt binder contains significant quantities of relatively low molecular weight products which add to the resiliency of the higher molecular weight bitumen forming the predominant part of the asphalt binder. These lower molecular weight components, often referred to as volatiles, typically have a boiling point of about 200 to 225° F. at one atmosphere. These volatile components are gradually lost from the asphalt with the passage of time. This loss of volatiles is particularly pronounced under high temperature conditions and high traffic conditions.
The loss of resiliency in the asphalt paving structure is generally most pronounced at the surface of the paving. Oftentimes, the paving structure, when it reaches the point where it is considered to no longer be useful, will still retain resiliency at the lower portions near the subgrade. Thus, the asphalt paving structure, when it is taken up and ultimately crushed so that it may be recycled or disposed of in a landfill, can contain portions of “dead” asphalt while at the same time having portions of more resilient “live” asphalt. The dead asphalt binder can be differentiated from the live asphalt binder in crushed asphalt concrete in terms of its physical properties. The crushed asphalt concrete containing dead asphalt binder is highly friable and crumbles easily so that the asphalt binder does not readily adhere to the surfaces of the aggregate particles. The recycled asphalt concrete containing substantial amounts of “live” asphalt binder is much less friable and rather than crumbling under release of compressive stress, will tend to form a less friable, more massive material which retains its integrity and it is not as easily crumbled. The live asphalt concrete is characterized by asphalt more readily adhering to the surfaces of the aggregate material than is the case with dead asphalt. The crushed recycled asphalt concrete employed in carrying out the present invention advantageously has the characteristics of a dead asphalt binder material. This material can be mixed with a minor amount of hydraulic cement, which after hydration with water, can be used to provide and asphalt paving surface which is relatively low in compressive strength and provides good compressability. This material can be advantageously used to provide a subgrade which can be covered with another paving material which is asphalt concrete or Portland cement-based concrete.
Turning now to the drawings, FIG. 1 illustrates a mixing assembly which can be used in carrying out the embodiment of the invention in which a crushed asphalt concrete as described above can be disposed on the surface of a conveyor followed by dispersing a hydraulic cement onto the layer of crushed asphalt concrete. The layer of crushed asphalt concrete and hydraulic cement is then supplied into a mixing mill. Water is sprayed into contact with the cement and crushed asphalt aggregate prior to mixing least a portion of the mixture of the asphalt aggregate and asphalt binder within the mill. More particularly and as illustrated in FIG. 1 , the mixing system disclosed there comprises a conveyor 10 which is supported on a plurality of rollers 12 which are rotated in order to advance the conveyor in the direction of a mixing mill 14 . Mixing mill 14 may be of any suitable type but preferably will take the form of an elongated pug mill. A preferred type of pug mill for use in the invention is a dual pug mill equipped with two counter-rotating agitators disposed longitudinally of the pug mill. A suitable pug mill is available from Aran America under the designation Model # ASR-25E.
The mixing system further is equipped with a plurality of hoppers 16 - 19 for dispensing crushed asphalt concrete an optionally for the supplemental addition of additional aggregate particles to the crushed asphalt concrete. More particularly and as illustrated in FIG. 1 , hoppers 16 and 17 each contain crushed asphalt concrete to provide for the supply of the crushed asphalt concrete onto the surface of the conveyor 10 in two successive increments. By supplying the crushed asphalt in a plurality of increments, a relatively even distribution of crushed asphalt concrete is formed on the conveyor surface which can be more readily contacted by the subsequent addition of the hydraulic cement component. Thus, as shown in FIG. 1 , the crushed asphalt concrete is formed in the surface of the conveyor 10 in a relatively thin layer 22 which has a depth on the conveyor surface which is substantially less than the width of the crushed asphalt mixture on the conveyor surface. For example, in a system employing a dual pug mill having a maximum capacity of about 500 tons per hour, the conveyor 10 may have a width of about 3-4 feet and the crushed asphalt concrete is disposed on the conveyor to provide a layer of crushed asphalt 22 having an average thickness of about 2-6 inches.
In further operation of the mixing system shown in FIG. 1 , the hydraulic cement component is fed from dispenser 20 , normally located immediately before the mill 14 , and spread over the surface of the layer of crushed asphalt concrete 22 . The hydraulic cement preferably is added in an amount within the range of 1-14 wt. %, and more preferably within the range of about 2-10 wt. % of the crushed asphalt concrete. Additional amounts of hydraulic cement can be employed, but this will usually not be desirable since the asphalt concrete layer ultimately formed is preferred to have a relatively low compressive stress to provide good compressability. Since the material will often be employed as a base material on which an additional paving surface is imposed, it will be desirable to provide for good compressability of the ultimate base material.
In one embodiment of the invention, an additional aggregate material may be supplied via hopper 18 and/or hopper 19 to the mixture on the conveyer 10 . The supplemental aggregate material should have a particle size distribution similar to the particle size distribution appearing in the crushed asphalt aggregate mixture as described below. The added aggregate material supplied via hoppers 18 and 19 should be limited in amount to ensure that the crushed recycled asphalt concrete (supplied via hoppers 16 and 17 ) remains the predominant component in the hydraulic cement, crushed asphalt concrete blend. This is important in order to retain significant recycled asphalt binder in the ultimate mixture to provide for good compressability in the final product. Thus, in adding additional aggregate from any source it should be added in an amount which is less than the amount of the crushed recycled asphalt concrete. Preferably, the additional aggregate supplied from hopper 19 should be less than ½ by weight of the recycled crushed asphalt concrete supplied from hoppers 16 and 17 . More preferably, the additional aggregate is less than 30 wt. % of the recycled asphalt concrete.
Variations in the order of addition as described above may be employed in practicing the present invention. For example, crushed asphalt concrete may be dispensed onto the conveyor surface via hoppers 16 and 18 with an intermediate addition of supplemental aggregate via hopper 17 . Also, the supplemental addition of aggregate via hopper 19 may be dispensed with or, alternatively, additional crushed asphalt concrete may be supplied via hopper 19 .
After or immediately before the supply of the mixed material to the mixing mill, water is added-in an amount effective to provide a plastic mixture of the crushed asphalt concrete and hydraulic cement within the mixing mill. Preferably, the water will be added from tank 23 at the front of the mixing mill in order to ensure that the plastic mixture of crushed asphalt concrete, hydraulic cement and water is formed in a relatively homogeneous mixture within the mixing mill. The water preferably will be added in an amount to provide a water content within the range of about 6-10 wt. % of the mixture in the mixing mill. More specifically, the final water content of the plastic mix will usually be within the range of 7-8 wt. %. In many cases, where supplemental aggregate is employed, the supplemental aggregate may contain substantial amounts of water. In this case, the water to be supplied from tank 23 will be added taking into account the amount of water in the supplemental aggregate. In some cases where the supplemental aggregate has a very high water content, it may be unnecessary to add additional water from water supply 23 .
In one embodiment of the invention, a water-reducing agent conforming to ASTM C-494 is added to the mixture prior to the addition of the water.
The hydrated mixture is withdrawn from the mill 14 and supplied by way of a loading chute 24 to a suitable product hopper for a conveyance, such as dump truck or the like (not shown). The mixture is then transported to the site where it is to be used and spread on to a substrate surface where it is graded and allowed to set to form the substrate surface. After the addition of the water, the plastic mixture has a relatively short “pot time” and it should be spread onto the substrate surface within about two hours after mixing in the mixing mill 14 . Under high temperature conditions, for example where the ambient temperature is about 100° F. or above or under windy or low humidity conditions, the pot time will be somewhat shorter and the aggregate mixture is preferably spread within one hour after mixing.
In a further aspect of the present invention, glass fibers may be incorporated into the crushed asphalt concrete prior to supply of the concrete to the mixing mill. The glass fibers may range in length from about ½ to 3 inches, and more specifically, within the range of about ½ to about 1½ inches. The length of the glass fibers can vary depending upon the size of the aggregate in the crushed asphalt concrete mixture, with larger sized aggregates calling for somewhat longer fibers. The glass fibers may be of any simple type such as Class AR fibers available from Saint-Gobain Vetrotex America-BUSPER. Preferably, the fibers will have a diameter of about 60 denier.
In a further embodiment of the invention, the crushed asphalt concrete, with or without the addition of more aggregate, may be supplied to a conveyor system incorporating a sieve shaker in order to avoid the supply of unacceptably large particles to the mixing mill. An embodiment of the invention incorporating this feature as well as providing for the addition of glass fibers is illustrated in FIG. 2 , which schematically shows the system for the supply of crushed asphalt concrete, aggregate, and fibers to the mixture to be supplied to the mixing mill.
More particularly and as shown in FIG. 2 , there is illustrated a system comprising an initial conveyor belt 28 which is supplied with materials from bins 31 , 32 , 33 and 34 . Bins 31 - 34 may be filled with crushed asphalt concrete and supplemental aggregate as needed. The crushed asphalt concrete and the supplemental aggregate may be added in any desired sequence. For example, crushed asphalt concrete may be supplied to the conveyor belt 28 via hoppers 31 and 33 and supplemental aggregate via hoppers 32 and 34 .
The initial conveyor belt 28 empties into a 2-inch sieve shaker 36 which, in turn, supplies its output to a secondary conveyor belt 38 . As noted previously, the sieve shaker may be set to retain particle sizes greater than a desired maximum, for example, two inches. Where the crushed asphalt concrete and supplemental aggregate, if any, is finely graded, the sieve shaker 36 may be dispensed with.
The output from the sieve shaker 36 is supplied via a second conveyor belt 38 to a third conveyor belt 40 . Conveyor belt 40 may be in the form of a weight belt conveyor system which weighs the amount of material on the conveyor belt and enables additives supplied via silos 42 , 43 and 44 to be controlled depending upon the weight of the material on the conveyor belt 40 . The glass fibers are supplied onto the crushed recycled asphalt concrete on they conveyor belt immediately before the hydraulic cement. Thus, the fibers are supplied via silo 43 and the hydraulic cement added immediately thereafter from silo 44 so that the cement covers the fibers as well as the other particulate material present. The glass fibers may be added in any suitable amount, but preferably will be within the range of about 1 to 2½ pounds per ton of dry material on the conveyor 40 . If any additional material such as a water reducing agent or the like are employed, it normally will be added through silo 42 prior to the addition of the glass fibers.
The material on conveyor 40 is supplied to a mixing mill 46 such as twin shaft pug mill as described above. Water is supplied from a tank 48 through a water distribution system 50 , such as a sparger, to the pug mill. The output from the pug mill is then applied to a final conveyor belt 52 and is supplied to a storage hopper 54 and ultimately to a vehicle (not shown) used to transport the material to the utilization site.
The layer of recycled asphalt concrete paving often will be employed as a subgrade for a final paving material. The final paving material may be an asphalt concrete or a hydraulic cement concrete. The recycled asphalt paving material normally will be laid down to provide a subgrade thickness of about 3-12 inches. The final paving surface may be an asphalt concrete, a hydraulic cement concrete as described above, or it may be a layer of asphalt (without the addition of aggregate) having a thickness of 2-6 inches.
As noted previously, the crushed recycled asphalt concrete will normally have an average particle size within the range of about ¼-¾ inch. A substantial portion of the aggregate particles have an exposed surface area which is substantially free of adhered asphalt material. Preferably, at least 50 wt. % of the aggregate particles, having an average particle size retained on a No. 4 sieve, will have an exposed surface area which is substantially free of adhered asphalt material. The material allows the plastic slurry to be formed with a relatively small amount of hydraulic cement to allow the ultimate formation of a sub-base material of relatively low compressive strength and high compressability as described previously. In a preferred embodiment of the invention, the particles in the crushed asphalt concrete have a sieve analysis as set forth in Table I.
TABLE I
Sieve Size
Percent Retained
Percent Passing
Percent Retained Ranges
1¾″
0
100
0
1¼″
0
100
1″
1
99
⅞″
3
97
0-35
¾″
7
93
½″
15
85
⅜″
22
78
10-55
#4
43
57
30-70
#8
59
41
#16
69
31
#40
78
22
60-85
#50
81
19
#80
86
14
#100
87
13
#200
90
10
85-100
While any suitable hydraulic cement may be employed in carrying out the present invention, it will be preferred that the hydraulic cement be selected from the group consisting of Type I, Type I/II, Type II, and Type III Portland cement mixtures thereof. Other cements such as Type IP or slag cement may be employed. A particularly preferred hydraulic cement is Type I/II Portland cement.
In experimental work respecting the present invention, recycled asphalt concrete in which the asphalt binder had a very low volatiles content was crushed to provide a mixture of asphalt binder material and aggregate particles. The asphalt binder material was “dead” as evidenced by the friable character of the binder material and aggregate. The mixture was characterized by virtually no elasticity so that the asphalt binder easily crumbled and did not readily adhere to the surfaces of the aggregate in the mixture. The aggregate had an average particle size of about ¼-¾ inch and was easily separated from the binder material. When an effort was made to manually compress the mixture of asphalt binder material and aggregate, upon release of the compressive force, the mixture fell apart under its own weight so that the asphalt binder material was, for the most part, segregated from the aggregate particles. The mixture of binder material and aggregate particles was blended with Type I/II hydraulic cement in an amount of about 87 wt. parts binder and aggregate and about 5 wt. parts cement. This mixture was then mixed with about 8 wt. parts water and the plastic mixture was then compacted and set in forms to form blocks having a thickness of about 3½ inch. The blocks were found to have a compressive stress to fracture after curing for 7 days of about 500 psi.
An internal face exposed by sawing the block in two is shown in FIG. 3 which is a photograph of the face. In FIG. 3 , the asphalt treated with cement is gray in color; the aggregates are generally white or dark gray and portions of the original asphalt which were not contacted with the hydraulic cement are black in color. As shown in the areas indicated by reference characters 60 , 62 and 64 , only a few of the aggregate particles, primarily those of small particle size of about ¼ inch or less, are embedded in or have substantial surface area contacted by the original asphalt. For the most part, the particles have surfaces indicated by the gray areas surrounding the particles which are free of the original asphalt binder.
Having described specific embodiments of the present invention, it will be understood that modifications thereof may be suggested to those skilled in the art, and it is intended to cover all such modifications as fall within the scope of the appended claims.
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Method of recycling a crushed asphalt concrete comprising a friable mixture of asphalt and aggregate particles produced by breaking down a recycled asphalt/aggregate concrete by milling or crushing or the like. The aggregate particles include a substantial portion of the surfaces thereof which are substantially free of adhered asphalt material. The crushed asphalt concrete is mixed with a minor amount of hydraulic cement and water to produce a plastic mixture of the crushed asphalt concrete and hydraulic cement. The plastic mixture is transported to a utilization site such as a building site, road or parking lot and spread on a substrate surface to provide a layer of asphalt concrete pavement. The layer of asphalt concrete pavement has a 7-day compressive strength, typically no more than 1,000 psi, e.g., 150-800 psi. The cement is present in an amount within the range of 1-14 wt. %, more specifically, within the range of 2-10 wt. % of the crushed asphalt concrete and any added aggregate. A mixing assembly comprises a moveable conveyor which loads to a mixing mill. The crushed asphalt concrete is deposited on the conveyor to provide a relatively thin layer of the crushed asphalt concrete. Hydraulic cement is dispensed on the layer of crushed asphalt concrete and the crushed concrete and hydraulic cement is conveyed to the mixing mill. Water is added in an amount effective to produce a plastic mixture. The plastic mixture is recovered from the mixing mill and transferred to a utilization site.
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BACKGROUND OF THE INVENTION
This invention relates to construction elements of the kind comprising two plates of nailable material and web strips that hold the plates together in spaced apart relationship and consist of elongated sinuous sheet metal strips having teeth along their longitudinal edges embedded in the respective plates, and to a method and apparatus for the manufacture of such elements on a commercial scale.
More particularly, the invention relates to the manufacture of construction elements of the kind described in Ser. Nos. 327,924, now U.S. Pat. No. 3,872,641, and 497,828, wherein the preferred embodiment has the form of a closed box with bottom and top (flange plates) of a nailable plate material such as plywood, particle board or fibre board. The side walls (webs) of the element comprises sheet metal strips, such as galvanized steel, which are bent or corrugated in the transverse direction and shaped with dowel-like teeth along their longitudinal edges. The element is assembled in a pressing operation whereby the teeth of the web strips are pressed into the plates so as to provide a connection of considerable strength and stiffness.
In previous publications relating to structures of the above kind, such as German published Pat. No. 1,004,790 and U.S. Pat. No. 3,538,668, nothing is disclosed about how such elements may be produced, and especially how the web strips prior to the pressing operation can be held in their proper positions with a predetermined distance between the edges of the plates and the web strips, how completely closed elements should be manufactured, or how long elements may be pressed with a short press. As pointed out in applicant's above mentioned patent application, the shapes of web strips and teeth disclosed in the abovementioned previous publications, are not suitable for use in load-bearing elements and, as far as is known, have never found any practical use.
Load-bearing elements of the kind mentioned in the preamble may, in particular, be used as floor and roof elements in smaller buildings, such as residential houses, and will therefore have a place in modern commercial housing manufacture. It is feasible to manufacture such elements in modular dimensions, for example, in widths of 60 and 120 cm, if desired up to 240 cm, and in lengths up to 12 m.
For the bottom and top of a box-shaped panel element, particle board is a suitable material, because it is cheap and is produced in large sizes and at the present time also in qualities suitable for use in load-bearing components.
Very high dimensional precision is required if such elements are to be installed on the building site without appreciable finishing work such as sanding or puttying and form a sub-floor upon which floor covering such as linoleum or carpets are to be laid.
In order to ensure such dimensional precision and hence a correct fit between individual panels, the manufacturing method will have to meet a number of conditions which will be discussed briefly below.
Firstly, the web strips must be placed and kept in correct positions prior to the pressing operation. This means that they must be placed vertically between the bottom and top plates and stand straight along the plate edges, in the sense that the extreme points of the corrugated contour lie on a straight line which is parallel to the plate edges at a certain specified distance from these. Deviations in this respect complicate the sealing and connection between adjacent elements and give the finished elements an unsatisfactory appearance.
Secondly, the top and bottom plates should be held in correct relative positions so that the plate edges are at all points aligned in the vertical direction. If one plate is displaced relative to the other, problems will arise when the elements are to be installed and joined, since there will appear unsightly clearances between adjacent top or bottom plates. Actually, the mutual displacements between top and bottom plates should at no point exceed 1 mm, a requirement which for elements of a length of, say 8 m or more, call for rather rigorous measures.
Thirdly, the total height (thickness) of the panel after pressing should be kept within very close tolerances, for example ± 0.2 mm. Larger deviations in this dimension yield a noticable step in the joint between adjacent elements and call for additional finishing operations on the building site.
Fourthly, it is of considerable practical importance that the production machinery can quickly and simply be adjusted from one element size to another. This consideration applies to the length as well as to the width of the element and, to a smaller extent, also to the height.
Further, for the manufacture of large elements, it is important that the pressing of the element does not call for a press which is as long as the element itself, since a press of for example 12 m length would be very demanding with regard to both cost and space and, besides, could not be utilized to its full capacity.
SUMMARY OF THE INVENTION
The present invention provides a method for the commercial manufacture of construction elements of the kind described above, which permits elements of large sizes to be produced in a rational manner and with very good dimensional accuracy. Further, the invention provides an apparatus for the manufacture of panel elements according to the method of the invention.
With a view to solving the problems and fulfilling the requirements discussed above, the method according to the invention chiefly consists in using web strips which are somewhat underdimensioned relative to their length in the finished element, and gripping the web strips with displaceably mounted gripping means and then mutually displacing the gripping means so as to stretch the web strips in their length directions so their respective desired lengths, whereafter the web strips and the top and bottom plates of the elements are brought into mutually correct positions and pressed together. The apparatus of the invention is accordingly primarily characterized in that means are mounted on a supporting structure which are movable relative to each other, are adapted to grip the extremities of the web strips and are adapted to be displaced relative to each other in the length directions of the web strips and thereby stretch the strips to their respective desired lengths and to keep them in this stretched condition during the pressing operation. Aligning means are also mounted for vertically aligning the plates relative to each other and to the stretched web strips.
Thus, the invention makes it possible to ensure that warps and unintentional curvatures in the web strips are eliminated and that the individual parts of the panel element are held in correct mutual positions during pressing and in such a way as to afford a high dimensional precision, and also permits the production to be carried out quickly and efficiently.
The invention also permits long elements to be produced with the use of a relatively short press, by pressing such long elements in several stages and using press plates which are shaped with slightly convergent entrance zones which form a smooth transition between that part of the element which is completely pressed and that part of the elements which have not yet been pressed.
The method according to the invention may conceivably be carried out with a large variety of means. Thus, the mentioned gripping- and centering means may be mounted on an endless chain, whereby the individual parts of the element are moved to a pressing site where the chain is held under tension, and from where this chain thereafter moves the finished element out. However, it is preferred to use a rigid frame on which the gripping and centering means are mounted for mutual displacement, so that by mutually displacing these means the web strips can be stretched and the plates be brought into correct positions relative to the web strips and to each other.
Further, features and advantages of the method and the apparatus according to the invention will become apparent from the following description of a preferred embodiment provided for the production of panel elements according to U.S. patent application Ser. No. 497,828 and with a preferred embodiment of web strips having a trapezoidal main corrugation profile and a corresponding Z-shaped tooth profile, and with the extremities of the longitudinal web strips clamped into folds in transverse web strips. The corrugation shape of the web strips may be adapted to the building module M = 100 mm.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a box-shaped panel element of the type described above.
FIG. 2 is a diagrammatic plan view of the elements, showing the location of the web strips within the element shown in FIG. 1.
FIG. 3 is an elevational view of the edge portion of a blank for the web strips prior to being formed into a corrugated shape.
FIG. 4 shows the web strips in section along the line 4--4 on FIG. 3 after corrugation.
FIGS. 5a-c shows diagrammatically in horizontal section three different stages of the formation of a fold connection between two web strips meeting at a right angle.
FIG. 6 shows in horizontal section the connection between longitudinal and transverse web strips in the elements of FIG. 1.
FIG. 7 shows in perspective view and on an enlarged scale a deformation connection between longitudinal and transverse web strips.
FIG. 8 is a broken plan view of a jig frame for the setting up of an element for pressing.
FIG. 9 shows on an enlarged scale a vertical section taken substantially along line 9--9 in FIG. 8.
FIGS. 10 to 12 shows certain details on a movable crossbeam for the jig in plan, elevation and vertical section (taken along line 12--12 of FIG. 11), respectively.
FIG. 13 is a plan view of a clamping unit on the jig.
FIG. 14 is an elevational view of the unit shown in FIG. 13 with certain parts omitted for the sake of clarity.
FIG. 15 shows a vertical section taken substantially along line 15--15 of FIG. 13.
FIG. 16 is an elevational view showing diagrammatically a detail of the clamping unit of FIG. 13.
FIG. 17 shows in a broken plan view the attachment of a movable side rail to the jig frame.
FIG. 18 shows a vertical section taken substantially along line 18--18 of FIG. 17.
FIG. 19 shows in vertical section means for external support of a longitudinal web strip.
FIGS. 20 and 21 are diagrammatic views showing in elevation and plan, respectively, a manufacturing plant for the elements.
FIG. 22 shows on an enlarged scale a wheel and roller track in cross-section taken substantially along line 22--22 of FIG. 21.
FIG. 23 shows an enlarged and somewhat exaggerated view of the shape of the entrance end of the press plates in longitudinal vertical section.
FIGS. 24a-d are diagrammatic elevational views showing different stages of a stepwise pressing of long elements.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIGS. 1 and 2 show a box-shaped panel element 1 comprising a lower plate 2, a top plate 3, longitudinal web strips 4, 4' and transverse end web strips 5, which are locked to longitudinal strips 4, 4' by deformation connections indicated at 21. FIG. 2 shows the positions of the web strips in element 1. The element thus forms a closed box and may be filled with mineral wool or other suitable insulating material. The top and bottom plates 3, 2 (flange plates) may be of particle board or plywood with a thickness of for example 10-20 mm, and the element height (thickness) may be typically 15-30 cm, the width 1.20 m or more and length up to 12 m.
A typical web strip for the element in FIG. 1 is shown in a broken in FIGS. 3 and 4. FIG. 3 shows a portion of the longitudinal edge of the web strip in flat condition, i.e. before the strip is bent along transverse fold lines into the profile shown in FIG. 4. The basic shape is a shallow trapezoidal corrugation with rather wide teeth which are located in such a way that they acquire a Z-shaped cross-section. The parallel, longitudinal portions 10 of this profile are near the transition of transverse portions 11 shaped with a stiffening groove 12, which primarily serves to afford a local stiffening of the flange portion 13, 13' of the Z-shaped teeth, which can thereby be made relatively wide without the free edges Y, Y' of the tooth buckling while being pressed into the flange plates. The wide flange portion of the tooth contributes considerably to the bending strength of the tooth in a direction transversely to the transverse portion 11 and also serves to give the tooth an increased pull-out anchoring strength by providing a larger tooth area as compared to a tooth with a simple Z-profile.
Symmetrically about the transverse planes of symmetry 15, 15' between subsequent teeth, the longitudinal portions 10 are shaped with shallow, troughlike depressions 17. The object of these is firstly to provide a local stiffening of the portions 1 which, due to their relatively large width, might otherwise be subject to buckling during the pressing. Secondly, such a trough-shaped depression 17 may serve as a starting point for a narrow fold within which a transversely adjoining web strip may be connected to the web strip 5.
This is shown in FIGS. 5a-c, which illustrate a pair of inwardly movable jaws 25 which the trough so as to pinch these edges together into a narrow fold 17'. A web strip 4 disposed at right angles to strip 5, can be inserted into fold 17' and locked to web strip 5 with rivets, spot welds, or by a deformation connection as described below with reference to FIGS. 7 and 13.
FIG. 6 shows how the longitudinal web strips 4, 4' are connected to the transverse strips through folding connections 20, 20' as described above. The web strips are furthermore locked together by a number of deformation connections 21 as shown in detail in FIG. 7. The lock 21 is formed by punching or shearing a loop-shaped protruding portion 23 in fold 17', the three layers of sheet metal being cut along lines 22, 22' and the intermediate portion 23 being pressed out in the shape of a shallow loop. Thereby vertical forces V may be transferred between web strips 4 and 5 through the mutual abutting contact between the sheared faces in the respective strips.
This force transferring connection between the longitudinal web strips 4, 4' and the transverse strips 5 gives the element 1 a considerable torsional strength and makes it possible to support the element at the ends in points located away from the longitudinal web strips, so that the elements can extend freely across window openings in the supporting wall.
The web strips are preferably made from hot galvanized sheet steel of 0.5 mm thickness. The trapezoidal corrugation profile shown having a Z-shaped tooth profile and stiffening grooves 12 and trough-like depressions 17 enables the web strips to be produced with a period length (distance between the symmetry lines 15, 15 for similarly oriented trapezia) of about 100 mm without the tooth being bent or the web strips buckling during the pressing operation. In practice, a period length of approximately 95 mm may be chosen, since the strip, as subsequently explained, is to be stretched about 5% when set up in the jig.
This has the great practical advantage that when, from a coil of web strip, a strip for an element of say 8 m length is to be cut, it is not necessary to measure this length, as it is sufficient simply to pass the strip through a counting device which counts 80 periods and thereafter cuts the strip along a line of symmetry 15. This strip will then have a length of about 760 cm and can be stretched in the jig to 795 cm, leaving at either end of the element a distance of 25 mm between the web strip and the plate edges.
With regard to the transversal end strips, the same procedure may be followed, the formation of the fold 17' providing a desirable additional shortening which is necessary since in this case the edge distance of 25 mm at either end in relation to the short strip length requires the web strip to be underdimensioned somewhat more than 5%. The formation of the fold 17' may conceivably be effected in the stressing jig by arranging the jaws of the clamping units as having a sufficient stroke length to clamp the trough-shaped depressions 17. Normally, however, it will be more practical and will in the following description be presumed that the folds 17' are formed in a prior, separate operation, so that also the end web strips are suitably underdimensioned when they are mounted in the jig.
A pre-requisite for employing a period length of 100 mm for web strips with such a small material thickness as 0.5 mm, is, however, that longitudinal portions 10 are stiffened as explained above. Consequently, it will be understood that this particular web shape, which is shown in FIG. 9 of U.S. application Ser. No. 497,828, constitutes a very valuable development of the simple trapezoidal shape shown in FIG. 13 of U.S. patent application Ser. No. 327,924.
There will now be described a tensioning frame or jig for the setting up of elements for pressing. The jig is shown diagrammatically in its main features in FIG. 8, and further details are shown in FIGS. 9 to 19.
The jig 30 has the shape of a frame comprising a pair of longitudinal beams 31, preferably in the form of rectangular hollow sections, rigidly connected to end beams 32, for example of flat steel. The frame has a bottom plate 33 (FIG. 9) which may be a thin steel plate. The bottom plate is connected to the longitudinal beams 31 through bolts 34, which can move vertically in guides 35 fixed to the beams 31. The plate 33 is fixed to the bolts 34 with screws and can therefore be lifted relative to the beams 31. In its lowermost position the plate 33 rests on the guides or sleeves 35, the top of the plate being in alignment with the top of the beams 31, as shown in FIG. 9. On the outside of each beam 31 there are attached a toothed rack 36 and a guide rail 37, for example in the shape of a round steel for which at intervals is attached to T-shaped brackets 38, which in turn are attached to the beams 31 with screws or by other suitable means (not shown).
The frame 30 further includes a pair of mutually movable transoms 40, one of which (to the right in FIG. 8) is preferably fixed near the end of the frame while the other is mounted movably along the frame. On the transoms 40 are placed clamping units 70, 70', in which the transverse and longitudinal web strips can be clamped and locked together. The clamping units 70 can be moved along the transoms and thereby stretch the end web strip 5 and, by moving the movable transom 40 in a direction away from the fixed transom, preferably by means of a driving unit 50 with motor, the longitudinal strips 4 can be stretched.
Still further, the frame 30 includes a pair of longitudinal rails 120, 120', which are placed inside the beams 31 and can be moved translatorily and synchronously towards and away from each other. On the side rails 120, 120' are placed detachable holding means 140, which carry aligning rulers 160. These rulers 160 support the longitudinal strips 4 externally and ensure, together with the holders 140, that the external web strips 4 remain upright in a straight line parallel to and correctly spaced from the longitudinal edges of the plates.
The frame 30 has such dimensions that the largest possible distance between the transoms 40 is somewhat greater than the greatest element length contemplated and the maximum possible distance between the opposite edges of the aligning rulers 160 is somewhat larger than the greatest element width to be considered.
Various details of movable transom 40 are shown in FIGS. 10 to 12. This transom comprises two steel bars 41 (tubular if desired) extending across the jig throughout the width of the latter. The steel rods 41 are fixed at each end to a block 42 which can move somewhat in a vertical direction on a guiding post 43, preferably with a ball bushing or sleeve 44. The guiding post 43 is rigidly mounted in a block 45, in which an open ball bushing 46 is also mounted, which runs on the steel bar 37. Further, block 45 is mounted on a side plate 47 rigidly connected to another open ball bushing 46', which together with the side plate 47 carries a horizontal mounting plate 48 for the driving unit 50. The driving unit 50 includes a motor 51 with a suitable reduction gear, the driven shaft of which carries a gear 52 which, through another gear 53 and a suitable disconnectable coupling 54, drives a shaft 55 which extends throughout the width of the jig 30. The shaft 55 is journalled near its ends in suitable bearings 56 and 57 and carries sprocket wheels 58 at its ends. Each of the sprocket wheels 58 drives a lower sprocket wheel 59 through a short chain drive 61. The sprocket wheel 59 is mounted on a short shaft 62 which in a suitable way is journalled on the bottom side of the mounting plate 48, and which on its other end carries a gear 53 which meshes with the tooth rack 36.
At the other end of the movable transom 40, the arrangement is similar as shown in FIGS. 10 to 12, however, without the driving unit 50, the gears 52, 53 and the coupling 54.
With the arrangement shown in FIGS. 10 to 12, the transom 40 can move back and forth along the jig frame 30 and, due to the two gears 36 which run synchronously on the racks 36, the transom will always be exactly at right angles to the length direction of the frame. The coupling 54 may preferably be of the electromagnetic friction type which protects the driving unit from over-loading, and which disconnects the transom gears from the motor when the current to the motor 51 is interrupted. Thereby, the transom 40 can easily be moved manually back and forth along the jig frame for quick adjustment, whereas the motor 51 is used when the web strips 4, 4' are to be tensioned.
The clamping units for the web strips 4, 5 will now be described with reference to FIGS. 13 to 16, which show such a clamping unit 70. As shown, this unit comprises a box 71 open at the top and the bottom and having holes in the side walls 72 permitting the box to slide along the rods 41 of the transom 40. On the front wall 73 of the box a plate 74 is supported for movement along the wall 73 via T-grooves and rails 77 as shown in cross-section in FIG. 15. Furthermore, a second plate 75 is fixed on the front wall 73. Jaws 76 and 76' are fixedly secured to movable plate 74 and the fixed plate 75. The position of the jaw 76 relative to the plate 74 can be regulated somewhat by means of a couple of adjusting screws 79 engaging screw-threaded bores in a reaction plate 78 on the plate 74, the holes for the fixing screws in the jaw 76 being shaped somewhat oblong (not shown) in order to allow for horizontal adjustment. For reasons of clarity, the parts 76-78 are not shown in FIG. 14.
The plate 74 with the jaw 76 can be displaced toward and away from the fixed jaw 76' by means of a shaft 81 which carries a hand lever 82 and extends through the box 71 between the rods 41, and which is journalled, preferably in needle bearings, in the front wall 73 and the opposite wall 73' of the box. The forward end portion of the shaft 81 is shaped as a crank or circular excentric 81', which moves the plate 74 horizontally through a bronze block 83, which can move with vertical guidance in a rectangular hole 84 in the plate 74, as shown in FIG. 14. Thereby a rotation of 180° of the shaft 81 with the handle 82 will move the jaw from the closed position shown in FIG. 13 to an open position.
In the movable jaw 76 are mounted punching elements 85, and in the fixed jaw 76' are formed corresponding recesses or grooves 86 (FIGS. 13 and 15) for the formation of the deformation connections as shown in FIG. 7.
The parts of the clamping unit 70 so far described are sufficient for clamping and locking longitudinal and transversal web strips together. In the form of the jig shown in FIG. 8, with three such clamping units on each transom, the central units 70' have only this function, and these units therefore do not need to include further parts than those described so far. These units are fixed on the transoms 40, for example with a set screw 87 (FIG. 13).
The outer clamping units 70 also function to stretch transverse strips 5 and therefore have to be somewhat movable along the respective transoms 40. This stretching movement takes place through a cam element 91 (FIGS. 13, 15 and 16) which is fixed to the shaft 81 and pushes against the one or the other side wall 92, 92' of a U-shaped element 90 which is fixed to the transom rod 41 with a pin 93 (FIG. 15), which extends into a bore in the rod 41.
The cam element 91 is shaped so that the clamping unit 70 performs its entire movement for stretching the end strip 5 during the first approximately 90° rotation of the shaft 81 from a starting position where the jaws 76, 76' are in the open position. During the remaining part of the rotation of the shaft it is only the jaw 76 that moves in order to clamp the transverse web strip to the extremity of the longitudinal strip. This is necessary in order that when the element has been pressed, it be possible to loosen the jaws sufficiently to move the transoms from each other so as to permit the element to be lifted out of the jig frame.
In addition to the described gripping devices the units 70 are also equipped with aligning or locating means for locating the top and bottom plates of the element so that these plates will lie in correct positions in relation to each other and also to the web strips. As shown in FIGS. 13 and 14 and as described below, this function is performed by means of two sets of vertically movable, spring-loaded abutting pins which engage the plate edges and prevent the plates from moving out of position in a transverse as well as in a longitudinal direction.
To the plate 73 there is fixed a tube 100 accomodating a pair of vertical pins 101, 101' and an intermediate compression spring 102. Vertical movements of the pins are limited by stopping pegs 103, 103', running in slots 104, 104' in the tube 100. The pins 101, 101' as well as corresponding pins on the opposite transom engage the terminal edges of the top and bottom plates, respectively, and ensure that these edges remain aligned vertically and do not move out of position. Due to the pins being able to be pushed into the tube 100, they can follow the movement of the flange plates of the construction element when these are pressed onto the web strips.
In order that after the bottom plate of the element has been placed on the bottom plate 33 of the jig with one edge abutting the lower locating pins of the fixed transom 40, the movable transom 40 can be displaced somewhat inwardly over the element bottom plate, so that the underdimensioned web strips 4, 4' can be placed in the clamping units 70, 70', the lower locating pin 101' is adapted to be lifted by a lever 105 pivoted on an axis in a point A (FIGS. 13, 15 and 16) on the front wall 73. The lever 105 bears against the peg 103' and against the cam element 91 so that the latter upon the rotation of the shaft 81 can cause lifting of the pin 101' against the pressure of the spring 102. When the unit 70 is closed and tensioned (i.e. the jaw 75 is in the position to the right as shown in FIG. 13), the position of the lever 105 is as shown in full lines in FIG. 16. When the shaft 81 is rotated 180° back to the starting position, so that the unit moves to the left and the jaws open, the peg 103' and hence the locating pin 101' are lifted as shown in dotted lines in FIG. 16.
For the lateral location of the plates of the elements a plate 115 is journalled on a shaft 116 in the plate 75 (only shown in FIG. 13) which plate 115 carries a vertical tube 110 similar to the tube 100 and containing correspondingly mounted upper and lower abutting pins, of which the upper pin 111 is seen in FIG. 13. A spring 117 urges the plate 115 with the tube 110 out towards the open position as shown in the drawing. The plate 115 with the tube 110 is urged into closed position when the movable side rail 120 (FIG. 8) is moved towards a lug 119 on the plate 115 until a stop screw 118 threaded into the plate 115, engages the jaw 76'. By this arrangement it is ensured that the side edges of the flange plates will remain aligned in the vertical plane and at a predetermined distance from the longitudinal strips 4.
In the event that it is not desired that the edges of the flange plates shall be aligned, for example if the upper plate is shaped with a tongue along one edge and a corresponding groove along the opposite edge, it is clear that the location or aligning of the plates may be effected correspondingly by not using one guiding tube or sleeve with two abutting pins, but two separate tubes each having one locating pin for the top plate and the bottom plate, respectively, or the abutting portions of the pins may have different diameters.
When high (wide) web strips and a great number of punching elements 85 in the jaws 76 are used, it may be rather heavy to move the shaft 81 manually with the handle 82. It may then be preferable to rotate the shaft 81 in some other manner, for example with a nut wrench which may be driven pneumatically or electrically. Furthermore, it is clear that the closing of the jaws can take place in various ways, for example through hydraulic cylinders.
With reference to FIGS. 8, 17, 18 and 19 there will now be described aligning means ensuring that the longitudinal strips 4 along the element edges are held in correct positions between their fixation points. This function is performed by the side rails 120, 120' with the holders 140 and the aligning rulers 160.
The side rails 120, 120' may preferably be steel flats as shown in cross-section in FIG. 18. The rail may be made in sections jointed by splice plates and screws as indicated at 121. On the bottom side of the rail are mounted ball rolls 122 suitably spaced, so as to permit the rail to move easily over the beam 31 and the bottom plate 33 of the jig. In each end the rail is fixed to a bracket 123 equipped with ball bushings 124 capable of running along a stationary transverse guide rod 125 fixed in stands 126, 126' on the jig frame. This arrangement ensures that the rail 120 at its ends is fixed against rotation in the horizontal plane, a fact which considerably increases the bending stiffness of the rail in the horizontal direction.
The two opposite side rails 120, 120' can be moved in parallel relation and synchronously towards and away from each other by means of a pair of transverse spindles 127 which are suitable journalled in the stands 126, 126' on the jig frame and which have oppositely threaded end portions passing through correspondingly threaded nuts 128 fixed in bearing blocks 129 on the respective brackets 123.
The two spindles 127, one on either end of the jig, are synchronized to a shaft 130 which extends along the jig frame and which is journalled in suitable bearings attached to the beam 31. This shaft is connected to each of the spindles 127 through a worm 131, a worm gear 132, a short transversal shaft 133 journalled in the beam 131, and gears 134, 135, as shown in FIG. 18.
The side rails 120, 120' can be moved by turning the shaft 130 by means of a motor not shown in the drawings.
FIG. 19 illustrates a holder 140 for the supporting and aligning rulers 160. The holder 140 comprises a sleeve 41 through which there passes a rod 142 which by the action of a pressure spring 143 and a stopping ring 147 on the rod is urged to the right in the drawing. The rod 142 slides in bearings 146 mounted in the sleeve 142. To the right end of the rod 142 there is fixed a vertical sleeve 150 which holds a fixed lower abutting pin 151 and an upper abutting pin 152 which can be pushed downwardly against the action of a compression spring 153. The movement of the pin 152 is limited by a stopping peg 154 movable along a slot 155 in the sleeve 150.
The abutting pins 151, 152 are formed with transverse grooves 156 receiving the rulers 160 which bear against the outside of the web strip 4 and are held in place in their respective grooves by spring-loaded locking pins 157 (only shown in the upper part of FIG. 19) mounted in the pins 151, 152 and having suitable semi-spherical end portions projecting into longitudinal grooves 161 in the rulers.
As shown, each of the abutting pins 151, 152 is formed with grooves 156 for two rulers. This is done to permit these sections of such rulers to overlap longitudinally whereby it becomes possible in a simple way to build up the desired length of lateral support.
As shown in FIG. 19, the holder 140 is detachably mounted on the side rail 120 with short pins 145 which are fixed in the sleeve 141 and fit into holes 139 (FIG. 17) drilled at suitable intervals in the rails 120.
The arrangement shown in FIG. 19 functions to ensure that the strip 4 will remain upright at the exact desired distance from the edges of the flange plates 2, 3 throughout the strip length between the clamping points. This is achieved by the abutting pins 151, 152 which are pressed against the edges of the flange plates, while the web strip 4 is pressed against the rulers 160 with a somewhat smaller outward pressure. This outward pressure may for example be provided by suitable insulating material such as mineral wool or similar material, placed inside the element, as indicated in the Figure.
The following sets forth the manner in which an element of the type shown in FIG. 1 is set up for pressing in the jig shown in FIG. 8.
The lower plate 2 is placed on the bottom plate 33 of the jig, with one end edge abutting against the lower abutting pins of the fixed transom 40 to the right in FIG. 8. The movable transom 40 is then displaced a certain distance inwardly over the lower element plate in the direction toward the fixed transom. For this to be possible, it is necessary that the units 70 on the movable transom are in their open position, so that the abutting pins 101' (FIG. 14) are lifted and do not bear against the end of the lower plate 2. Thereafter the transverse web strips 5, with the folds 17' preferably already formed, but not yet completely pinched together, are placed between the jaws 76, 76' of the respective units 70, 70'.
As previously mentioned, the longitudinal strips 4, 4' are cut to a somewhat shorter length, typically about 5% shorter, than the length of the element to be manufactured. These strips are cut along the line of symmetry in the trough-shaped depressions 17 as shown in FIG. 5c. The ends of the strips 4, 4' are now placed in the respective folds in the transverse strips 5, and the units 70, 70' are closed by means of the handles 82 as explained above. At the same time the deformation connections 21 are formed and the exterior units 70 are displaced somewhat outwardly along the respective transoms as a consequence of the cam element 91 pushing against the fixed element 92' (FIG. 13) whereby the end strips 5 are stretched. The lever 105 moves to its lower position (FIG. 16) so that the abutting pins 101' are free to be pushed downwardly toward the upper side of the lower plate 2. The movable transom 40 can then be moved rearwardly towards the left in FIG. 8) by means of the driving unit 50 until the abutting pins 101' on the same come outside the left terminal edge of the lower plate 2. If required, the transom 40 is then moved a bit forwardly again in order to bring the abutting pins 101 to bear firmly against the edge of plate 2.
The longitudinal web strips 4 have now been stretched so strongly that warps and undesirable curvatures which always are present in such strips from the strip production process, have largely been eliminated, and the strips are standing as tensioned strings.
Now, the side rails 120, 120' with the holders 140 and the supporting rulers 160 are moved towards each other and thereby force the plate 115 with sleeve 110 to turn around the shaft 116 (FIG. 13) until the stopping screw 118 bears against the jaw 76. During this movement, which takes place in all the four corners of the element, one or two of the lower abutting pins in the sleeves 110 pushes the lower plate laterally to its correct position if the plate is not already lying correctly. The plate 2 will then be locked or clamped in the desired position relative to the corner joints 20 between longitudinal strips 4 and end strips 5.
As the side rails 120, 120' are moved towards each other, the abutting pins 151 in the holders 140 will come to bear resiliently against the longitudinal edges on the plate 2, and the rulers 160 ensure the desired distance between the strips 4 and the edges of the plate.
Insulating material may now be placed between the web strips. This material may preferably be mineral wool mats which are cut accurately in the direction of width so as to press the outer web strips 4 outwards towards the rulers 160. The internal longitudinal web strip 4 will be subject to approximately the same pressure on both sides and this fact together with the tension in the strip is sufficient for the strip to adjust itself to a reasonably correct position. Actually, the central strip will sometimes be standing somewhat out of plumb and also not completely straight as seen from above, but experience has shown that with the shape of the teeth and the strip profile shown in FIGS. 3 and 4 complete embedding of the teeth and an absolutely satisfactory connection between the web strip and the flange plates are achieved.
The top plate 3 can now be put in place abutting against the respective pins 101, 111 and 152, and the element is ready for pressing.
With reference to FIGS. 20 to 24 there will now be described an embodiment of an apparatus wherein the jig with the element set up therein is transported into and out from a press designed for stepwise pressing of long elements.
As shown diagrammatically in elevation in FIG. 20 the jig frame 30 rests on a wheel and roller track 200. The side beams 31 of the jig rest on stationary wheels 201 shaped with flanges affording lateral stability of the jig frame (also shown in dotted lines in FIG. 9). The bottom plate 33 of the jig rests on rollers 202. The supporting structure for the wheels and the rollers (FIG. 22) includes legs 203 bolted to the floor, and transverse beams 204 which carry longitudinal beams 205, 206 on which the wheels 201 are journalled. To the upper ends of the legs 203 are welded longitudinal beams 207 with a channel section, and a central longitudinal channel beam 208 is carried by short struts welded to the transverse beams 204. In the longitudinal beams 207, 208 the rollers 202 are journalled.
A drive chain 220 is arranged in an endless loop with its upper course in the channel beam 208 and its lower course suspended under the transverse beams 204. The chain is passed around sprocket wheels 221, 221', 222, 222' at either end of the wheel and roller track 200. The chain is driven by a motor with a suitable brake, diagrammatically indicated at 225 in FIG. 20. The arrangement shown is such that the rear end of the jig, point 226 in FIG. 20, can only be moved up to the rear end of the roller track 200, approximately up to the sprocket wheel 222, so that the extreme rear portion of the jig cannot be utilized for accomodating the element. Although this means that some space is lost, this arrangement has the advantage that a walking passage is obtained between the wheel and roller track 200 and the press 230, a fact which very considerably facilitates the operation of the manufacturing line.
As shown in FIG. 21, along the sides of the press plate 231' there are also provided stationary wheels for supporting the jig frame, and furthermore, on the rear side of the press, to the right in FIGS. 20 and 21, there is mounted a wheel and roller track 210 of a similar design as the track 200, but without the chain drive 220, so that it is possible to move the jig into and through the press as far as the length of the set up element requires, with the limitation stated above.
As shown in FIGS. 20 and 21 the press 230 is considerably shorter than the longest element which the jig 30 can accommodate. For reasons of clarity, only the press plates are shown, and it is assumed that the lower press plate is fixed while the upper press plate moves up and down. The press may be hydraulic or mechanical and may be of known design, apart from one detail which will be discussed below. It is, however, of considerable importance that the upper press plate is guided vertically, so that during the working stroke it will move in parallel relation to the lower press plate, without any horizontal displacement in the longitudinal or transverse direction. Furthermore, it is required that the movable press plate will stop its movement when the element has been pressed to the exact desired height, regardless of the pressing force or specific pressure which might be attained. In other words, the press must be controlled by movement rather than by force. The design of a suitable press does not involve specific or unusual problems and can be performed with well known technology.
As shown in FIG. 20 and somewhat exaggerated in FIG. 23, the press plates are shaped with gently converging end portions 232 at the entrance end. This makes it possible to press long elements in several steps. The converging portions 232 then function to provide a smooth transition between that part of the element which in one pressing step is being pressed completely and that part of the element which is not yet pressed, so that the flange plates 2, 3 will attain a smooth and well controlled curvature which is well within that maximum deformation to which the plate material can be subjected without damage. Experiments have shown that a particle board plate is more or less sheared off if one attempts to press an element in steps with ordinary flat press plates without a transition zone as described.
In FIG. 23 the transition portion 232 is shown with a gentle S-shaped curvature with horizontal end tangents. Such a curve may be expressed mathematically as a trigonometric function or as a polynomal function or may simply be designed graphically. The transition zone 232 may also be made up of a number of inclined surfaces or simply be one inclined plane of sufficient length. The main point is, as mentioned above, that a smooth transition is achieved between the completely pressed and the not yet pressed part of the element with a continuously decreasing embedding of the web teeth into the flange plates 2, 3. The extremities of the transition zone should consequently be at levels with a difference corresponding to the penetration depth of the teeth in the respective plates, that is the length of the teeth.
FIGS. 24a-d illustrates diagrammatically four situations during the pressing of a long element, corresponding to two pressing steps. For the sake of clarity, the web plates 2, 3 of the element has been shown as single lines, and difference between the levels of the extremities of the transition portion is somewhat exaggerated.
FIG. 24a shows the setup element as it has been transported into the press, but before the first stage has been pressed. The plates 2, 3 and the web strips 4 are then not structurally interconnected and the individual components adjust themselves to the shape of the lower press plate. It is to be noted tht the front part of the element with the front end strip 5 is lifted somewhat relative to the entrance level 240 and therefore also relative to the jig frame, which in all positions lies at the same level (the top of the beam 31 is at level 240). In order to follow this lifting movement the bottom plate 33 of the jig is mounted vertically movable relative to the jig frame 31, 32 as mentioned in connection with FIG. 8, and the transoms 40, to which the web strips are clamped, can also move somewhat in the vertical direction relative to the frame 31, 32 (see FIGS. 10 to 12).
FIG. 24b shows the situation after the first part of the element has been pressed. During the pressing the bottom plate of the jig and the foremost transom 40 move down again to the normal position. After pressing, the upper press plate 231 is lifted anew, and the jig 30 is moved forward to the position shown in FIG. 24c, where the major part of the pressed element protrudes outside the press, while a smaller part C1-C2 lies in the press in order to guide the element so that the part being pressed in the second stage will be aligned with the part already pressed, and hence the element becomes straight. As indicated in FIG. 24c, one or more spring-loaded rollers 245 may be used as a temporary support for the protruding part of the element.
FIG. 24d shows the situation after pressing of the second stage, that is with the press plates in the same position as in FIG. 24b. The pressing of the remaining stages takes place in a manner similar to what has been explained above.
Thus, the production of an element includes the setting up of the element in the jig as described above. The jig then lies on the wheel and roller track 200 as shown in FIG. 20. By means of the chain drive 220 the jig is pulled into the press and stops in the position shown in FIG. 24a. The upper press plate goes down and presses the element to the desired height (thickness). The upper press plate goes up, and the jig is moved one step forward into the press, whereafter the next portion is pressed. This is repeated until the whole element has been pressed.
Thereafter the jig is pulled back to its starting position. In order to be able to lift the element out of the jig it is necessary first to move the side rails 120, 120' away from each other. Thereafter the clamping units 70, 70' on the fixed transom 40 are opened. This is done by turning the shafts 81 in the respective units about 90° (FIG. 13) so that the jaws 76, 76' move away from each other, but not so much that the excentrics 91 attempt to move the units inwards on the transoms, since the channel folds on the end strips 5 in which the longitudinal web strips 4, 4' are locked, have now been fixed to the flange plates 2, 3 and therefore prevent such movement.
Thereafter the movable transom 40 is driven rearwardly (to the left in FIG. 8), so that the element can be pulled away from the fixed transom 40. Now the clamping units 70, 70' on the movable transom 40 are opened, and this movable transom is then driven still further backwards so that the element will lie freely on the bottom plate 33, whereafter it can be lifted out of the jig with a suitable hoisting device.
It is possible to make the stepwise movement of the jig through the press and the appurtenant activation of the press automatic, so that no manual operation is required from the moment when the jig starts its movement towards the first pressing position till the moment when it returns to its starting position. This can be done with known technology.
Also it is obvious that it is possible to make various modifications, substitutions, omissions and additions to the manufacturing apparatus and method described above and shown in the drawings, within the scope of the invention as defined in the appending claims.
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Construction elements comprising two parallel nailable plates interconnected by corrugated metallic web sheets extending edgewise between them and having teeth at their edges embedded in the plates are made by placing the bottom plate thereof in a movable frame having displaceable abutments connected to clamping means. The web sheets are placed in positions so as to be clamped at their extremities by the clamping means, the extremities of longitudinal sheets being pinched in folds of transverse end sheets. Also, interlocking deformations are punched in the adjoining webs. The clamping means are moved for stretching the sheets, the upper plate is placed on top, and web sheets and plates are brought into correct relative positions by corresponding positioning of the abutments. In addition longitudinal web sheets extending along edges of the element are supported externally between clamping points by spring-loaded rulers connected to abutments so as to ensure correct spacing from the plate edges. With the components of the element thus aligned the frame is moved into a press and the components are pressed together, the abutments yielding vertically against a spring-load. Then the frame with the element is removed from the press, and the grip by the abutments and clamping means is released. For permitting stepwise pressing of elements longer than the press the latter has a smoothly converging entrance portion. In its preferred form the web sheet has a largely trapezoidal corrugation, a Z-shaped cross-section of the teeth and shallow depressions between the consecutive teeth, suited as starting points for folds to be formed.
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RELATED APPLICATIONS
This application claims priority from U.S. Provisional Patent Application Ser. No. 60/469,737 which was filed on May 12, 2003.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an efficient three-step process for the preparation of 7-alkyl-10-hydroxy-20(S)-camptothecin from the readily available natural product, 20(S)-camptothecin. The invention also demonstrates a novel intermediate useful in this synthesis.
2. Description of the Related Art
Camptothecin derivatives have shown significant cytotoxic activity and several have been developed into useful pharmaceuticals. Specifically Irinotecan (Campto) has shown excellent activity toward colon-rectal cancers and is widely marketed. It shows considerable advantage over other camptothecin derivatives in that it is water soluble.
Irinotecan is prepared in several steps from the key intermediate, 7-ethyl-10-hydroxy-20(S)-camptothecin. Considerable effort has been expended to introduce both the 10-hydroxy and the 7-ethyl functionality into the camptothecin molecule. Therefore, while there is some prior art associated with each of these individual groups, there is very little knowledge on introduction of both these functionality simultaneously into the molecule.
Sawada (Chem. Pharma. Bull., 39(12), 3183(1991) demonstrates the synthesis of 7-ethyl-10-hydroxy-20(S)-camptothecin through the synthesis of 7-ethyl-20(S)-camptothecin by known means, the subsequent formation of an N-oxide and the photochemical rearrangement to provide 7-ethyl-10-hydroxy-20(S)-camptothecin. However, this synthesis suffers considerably from the insolubility of 7-ethyl-20(S)-camptothecin in suitable solvents and thus only small quantities can be prepared.
10-Hydroxy-20(S)-camptothecin has been prepared by the hydrogenation of 20(S)-camptothecin to 1,2,6,7-tetrahydro-20(S)-camptothecin and subsequent oxidation. Thus U.S. Pat. No. 5,734,056 describes the preparation through the hydrogenation of 20(S)-camptothecin to 1,2,6,7-tetrahydro-20(S)-camptothecin followed by the oxidation with iodosobenzene derivatives specifically esters such as iodobenzenediacetate. Japanese pat. No. 59-5188 discloses the hydrogenation of camptothecin followed by oxidation with agents such as CAN(cerium (IV) ammonium nitrate, chromic acid, potassium permanganate, Fremy's salt. Similarly, Sawada, et. al. (Chem. Pharm. Bull. 39(120)3183, 1991) describes a reduction and oxidation with lead tetraacetate. In all these cases, the use of a 7-substituted derivative has not been demonstrated.
The preparation of 7-ethyl-20(S)-camptothecin has been demonstrated previously through the Fenton reaction by employing 20(S)-camptothecin and propionaldehyde with ferrous sulfate and sulfuric acid.
Therefore there is a need for an efficient synthesis of 7-ethyl-10-hydroxy-20(S)-camptothecin which can be used in commercial scale.
SUMMARY OF THE INVENTION
The present invention provides as one embodiment a novel process employing the formation of the 7-ethyl-20(S)-camptothecin followed by the catalytic reduction and subsequent oxidation to the desired 7-ethyl-10-hydroxy-20(S)-camptothecin, shown in Scheme I, which is useful in the synthesis of Irinotecan.
DETAILED DESCRIPTION OF THE INVENTION
The formation of 7-alkyl-20(S)-camptothecin (I) was accomplished by known methodology. It is known in the literature that the hydrogenation of tetra-substituted olefins is very difficult. Therefore, it was expected that the hydrogenation of this compound to 7-alkyl-1,2,6,7-tetrahydro-20(S)-camptothecin (II) would be challenging. We were surprised to learn that we could indeed accomplish this hydrogenation in good yield and good purity using PtO 2 as the catalyst in a suitable solvent in which the 7-alkyl-20(S)-camptothecin is soluble. Catalysts other than PtO 2 may be used, such as reduction catalyst containing at least one of the elements platinum, rhodium, lawrencium, and ruthenium. Further, the hydrogenation step may be conducted with a catalysis modifier, such as dimethylsulfoxide and ammonium hydroxide. Acetic acid is a preferred solvent for this purpose. Other solvent systems such as alcohols and mixtures of acetic acid and alcohols can be employed in this hydrogenation but high solubility of camptothecin in acetic acid makes acetic acid the most desirable solvent. By employing this catalytic hydrogenation, the desired product can be easily obtained in greater than 90% yield.
It was found that unlike the known 1,2,6,7-tetrahydro-20(S)-camptothecin, 7-alkyl-1,2,6,7-tetrahydro-20(S)-camptothecin (II) is oxidized readily back to 7-alkyl-20(S)-camptothecin (I) under an oxygen atmosphere. Therefore there was a question as to whether the oxidation would produce the 10-hydroxy derivative in good yield. In fact, the oxidation with iodobenzenediacetate in acetic acid/water did produce the desired 7-alkyl-10-hydroxy-20(S)-camptothecin (III) in very good yield. The reaction can be carried out in a variety of solvent systems but again acetic acid/water was the most convenient and preferred solvent system. Other suitable solvents include C 1 –C 6 ester, C 1 –C 6 acid, C 1 –C 6 alcohol and water. More specifically, the C 1 –C 6 acid may be butenic acid, propanoic acid and acetic acid. The reaction may also be carried out with various other oxidizing agents, including those containing hypervalent iodine, ruthenium (VIII), manganate (VII), osmium (VIII), lead (IV) and chromium (VI). The product precipitates during the reaction and can be collected by filtration. The product obtained is of sufficient purity to be used directly or it can be purified by recrystallization from organic solvents such as acetic acid.
Therefore the present invention provides for an efficient synthesis of 7-alkyl-10-hydroxy-20(S)-camptothecin (III).
EXAMPLES
Preparation of 7-ethyl-20(S)-camptothecin (I)
20(S)-camptothecin (60.0 g), ferrous sulfate heptahydrate (12.0 g) and 9N sulfuric acid (1200 ml) are subsequently charged to a 5-L reactor equipped with a mechanical stirrer, condenser and a thermometer under nitrogen atmosphere. The resulting mixture is stirred at 25° C. until all the suspension is dissolved, and it is cooled to between −10 and 0° C. Propionyl aldehyde (10.0 g) is added to the cold reaction mixture. A solution of 10% hydrogen peroxide (116.9 g) and propionyl aldehyde (15.0 g) are simultaneously charged to the cold reaction mixture over a period of 30–60 minutes, while maintaining the temperature at 10 to 0° C. The resulting mixture is stirred at the same temperature for 60 to 90 minutes. The reaction mixture was diluted with water and neutralized with aqueous ammonium hydroxide to precipitate out the desired product. The crude product was crystallized from acetic acid and water to give compound I, 49.83 g in 71.6% yield with purity of 95.16% by HPLC. 1H-NMR (DMSO-d 6 ) δ: 0.9 (3H, t), 1.3 (3H, t), 1.85 (2H, q), 3.2 (2H, q), 5.28 (2H, s), 5.44 (2H, s), 6.5 (1H, s), 7.32 (1H, s), 7.7 (1H, dd), 7.85 (1H, dd), 8.15 (1H, d), 8.26 (1H, d).
Preparation of 7-ethyl-1,2,6,7-tetrahydro-20(S)-camptothecin (II)
7-ethyl-20(S)-camptothecin (I) (30.0 g) and acetic acid (900 ml) were charged together and heated to 80° C. to facilitate the dissolution. The resulting solution is then transferred to a 2-L autoclave reactor and cooled to room temperature. Ammonium hydroxide (30% contents, 3.4 ml), platinum oxide and dimethyl sulfoxide (2.2 ml) were added into the resulting suspension at 25° C. The resulting mixture is then subjected to hydrogenation at a hydrogen pressure of 5 bars until the starting material, 7-ethyl-20(S)-camptothecin I, disappeared by TLC analysis. The catalyst was removed by filtering through a pad of celite and washed with acetic acid, the resulting solution is used directly for the next reaction. The sample was characterized by HPLC, NMR, IR and LC/MS analysis. HPLC shows three diastereoisomers in a ratio of 6: 61: 13, which are detected by LC/MS to have MS m/z: 380 (M 30 ). 1H-NMR (DMSO-d 6 ) δ: 0.78 (3H, t), 0.82(3H, m), 1.2–1.35 (2H, m), 1.8 (3H, m), 2.65 (1H, m), 3.12 (1H, m), 3.75 (1H, dd), 4.08 (1H, dd), 4.92 (1H, dd), 5.23 (1H, s), 6.48 (1H, s), 6.5–6.98 (4H, m), 6.62 (1H, s); IR (KBr) v: 3310, 2967, 1744, 1652, 1586, 1491, 1465 cm −1 .
Preparation of 7-ethyl-10-hydroxy-20(S)-camptothecin (III)
The hydrogenated filtrate of 7-ethyl-1,2,6,7-tetrahydro-20(S)-camptothecin was charged to a 3-L, four-necked round bottom flask equipped with a mechanical stirrer, thermometer under nitrogen atmosphere, and was cooled to 10° C. Water (900 ml) was added to the solution and the resulting solution was stirred at this temperature for 20 minutes. Subsequently, iodobenzene diacetate (65.5 g) was added to the solution in several small portions, while maintaining the temperature below 10° C. The resulting mixture was stirred at this temperature until the complete disappearance of the starting material, 7-ethyl-1,2,6,7-tetrahydro-20(S)-camptothecin (II), as monitored by TLC. The reaction was quenched by the addition of Methanol (230 ml) to facilitate the precipitation of the product. The reaction slurry was then filtered and the collected solids are washed with aqueous acetic acid and methanol to give the desired product 28.3 g (90% overall yield in two steps). 1H-NMR (DMSO-d 6 ) δ: 0.9 (3H, t), 1.32 (3H, t), 1.88 (2H, q), 3.1 (2H, q), 5.28 (1H, s), 5.42 (1H, s), 6.46 (1H, s), 7.28 (1H, s), 7.4 (2H, m), 8.0 (1H, d), 10.5 (1H, s).
Preparation of 7-methyl-20(S)-camptothecin
We performed a process corresponding to the above process to make 7-ethyl-20(S)-camptothecin to provide the product, 25.6 g in 60% yield. 1H-NMR (DMSO-d 6 ) δ: 0.90 (3H, t), 1.88 (2H, m), 2.79 (3H, s), 5.29 (2H, s), 5.44 (2H, s), 6.51 (1H, s), 7.34 (1H, s), 7.73 (1H, t), 7.86 (1H, t), 8.15 (1H, d), 8.25 (1 H, d).
Preparation of 7-methyl-1,2,6,7-tetrahydro-20(S)-camptothecin
We performed a process corresponding to the above process to make 7-ethyl-1,2,6,7-tetrahydro-20(S)-camptothecin. HPLC of the product shows three diastereoisomers in a ratio of 13: 68: 19, 1H-NMR (DMSO-d 6 ) δ: 0.78 (3H, t), 1.02 (3H, d), 1.72 (2H, m), 1.90 (3H, m), 3.01 (1H, m), 3.17 (1H, m),3.91 (1 H, m), 4.06(1H, m), 4.91 (1H, m), 5.21 (1H, s), 6.30 (1H, s), 6.56–6.6 (2H, m), 6.8–7.0 (2H, m).
Preparation of 7-methyl-10-hydroxy-20(s)-camptothecin
We performed a process corresponding to the above process to make 7-ethyl-10-hydroxy-20(s)-camptothecin (III). The HPLC of the reaction product shows 17% of the desired product and 41% 7-methyl-20(S)-camptothecin.
References that are cited herein are incorporated by reference in their entirety.
Thus, while there have shown and described and pointed out fundamental novel features of the invention as applied to a preferred embodiment thereof, it will be understood that various omissions and substitutions and changes in the form and details of the process illustrated, and in its operation, may be made by those skilled in the art without departing from the spirit of the invention. For example, it is expressly intended that all combinations of those elements and/or method steps which perform substantially the same function in substantially the same way to achieve the same results are within the scope of the invention. Moreover, it should be recognized that structures and/or elements and/or method steps shown and/or described in connection with any disclosed form or embodiment of the invention may be incorporated in any other disclosed or described or suggested form or embodiment as a general matter of design choice. It is the intention, therefore, to be limited only as indicated by the scope of the claims appended hereto.
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The key intermediate in any synthesis of Irinotecan is 7-ethyl-10-hydroxy-20(S)-camptothecin. A process for the efficient synthesis of this intermediate is demonstrated proceeding through readily available 20(S)-camptothecin. Various other tecan compounds may be made by use of corresponding 7-alkyl-10-hydroxy-20(S)-camptothecin intermediates.
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CROSS-REFERENCE TO RELATED APPLICATIONS
[0001] This application is based upon and claims the benefit of priority from the prior Japanese Patent Application No. 2009-201257, filed on Sep. 1, 2009; the entire contents of which are incorporated herein by reference.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The present invention relates to a semiconductor integrated circuit, and, more particularly is suitably applied to a method of improving electrostatic discharge immunity of the semiconductor integrated circuit.
[0004] 2. Description of the Related Art
[0005] In a semiconductor integrated circuit, to protect an internal circuit formed on a semiconductor chip, in some case, an electrostatic protection circuit is provided on the same semiconductor chip.
[0006] For example, Patent Document 1 “Mong-Dou Ker and Kun-Hsien Lin ‘ESD Protection Design for I/O Cells With Embedded SCR Structure as Power-Rail ESD Clamp Device in Nanoscale CMOS Technology’ IEEE JOURNAL OF SOLID-STATE CIRCUITS, VOL. 40, NO. 11, NOVEMBER 2005” discloses a method of providing silicon controlled rectifiers (SCRs) connected between power supply wires in input cells and output cells and, when electrostatic discharge is detected between the power supply wires, turning on the SCRs to thereby protect an internal circuit from electrostatic discharge damage.
[0007] Patent Document 2 “James W. Miller, Melanie Etherton, Michael G. Khazhinsky, Michael Stockinger, and James C. Weldon ‘Comprehensive ESD Protection for Flip-Chip Products in a Dual Gate Oxide 65 nm CMOS Technology’ EOS/ESD SYMPOSIUM 06-186 4A.4-1 TO 4A.4-10” discloses a method of providing field effect transistors connected between power supply wires in I/O cells and, when electrostatic discharge is detected between the power supply wires, turning on the field effect transistors to thereby protect an internal circuit from electrostatic discharge damage.
[0008] However, in the methods disclosed in Patent Documents 1 and 2, the SCRs or the field effect transistors are used to protect the internal circuit from electrostatic discharge damage. Therefore, a trigger circuit is necessary and, moreover, a device area is increased to improve a discharge ability.
[0009] In the method disclosed in Patent Document 1, because the SCRs are used, responsiveness to a high-speed surge is poor. In the method disclosed in Patent Document 2, because the field effect transistors are used, uniform operation performance is poor.
BRIEF SUMMARY OF THE INVENTION
[0010] A semiconductor integrated circuit according to an embodiment of the present invention comprises: a first power supply pad arranged in a peripheral section of a semiconductor chip; a second power supply pad arranged in the peripheral section of the semiconductor chip; a first power supply wire connected to the first power supply pad; a second power supply wire connected to the second power supply pad; an internal circuit formed on the semiconductor chip, power being supplied thereto via the first power supply wire and the second power supply wire; input and output pads that exchange an input signal or an output signal with the internal circuit; input and output cells including first electrostatic protection elements that protect the internal circuit from electrostatic discharge between the input and output pads and the first or second power supply wire; and second power supply protection elements provided adjacent to the input and output cells and including diode strings connected between the first power supply wire and the second power supply wire.
[0011] A semiconductor integrated circuit according to an embodiment of the present invention comprises: a first power supply pad arranged in a peripheral section of a semiconductor chip; a second power supply pad arranged in the peripheral section of the semiconductor chip; a first power supply wire connected to the first power supply pad; a second power supply wire connected to the second power supply pad; an internal circuit formed on the semiconductor chip, power being supplied thereto via the first power supply wire and the second power supply wire; input and output pads that exchange an input signal or an output signal with the internal circuit; input and output cells including first electrostatic protection elements that protect the internal circuit from electrostatic discharge between the input and output pads and the first or second power supply wire; and second power supply protection elements provided in the input and output cells to be arranged between the first power supply wire and the second power supply wire and including diode strings connected between the first power supply wire and the second power supply wire.
[0012] A semiconductor integrated circuit according to an embodiment of the present invention comprises: a first power supply pad arranged in a peripheral section of a semiconductor chip; a second power supply pad arranged in the peripheral section of the semiconductor chip; a first power supply wire connected to the first power supply pad; a second power supply wire connected to the second power supply pad; an internal circuit formed on the semiconductor chip, power being supplied thereto via the first power supply wire and the second power supply wire; first and second input and output pads that exchange an input signal or an output signal with the internal circuit; a first diode string connected between the first power supply wire and the second power supply wire such that a forward direction of the connection is a direction from a high potential side to a low potential side, the first diode string forming a discharge path for a surge current input to the first input and output pad; and a second diode string connected between the first power supply wire and the second power supply wire such that a forward direction of the connection is a direction from a high potential side to a low potential side, the second diode string forming a discharge path for a surge current input to the second input and output pad.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] FIG. 1 is a plan view of the schematic configuration of a semiconductor integrated circuit according to a first embodiment of the present invention;
[0014] FIG. 2 is an enlarged plan view of an A section shown in FIG. 1 ;
[0015] FIG. 3 is a diagram of an equivalent circuit of the A section shown in FIG. 2 ;
[0016] FIG. 4 is a diagram of an equivalent circuit of each of power supply protection elements including diode strings S 2 to S 6 provided among input and output cells shown in FIG. 3 ;
[0017] FIG. 5 is a plan view of a layout configuration of the power supply protection elements including the diode strings shown in FIG. 4 ;
[0018] FIG. 6 is a plan view of the schematic configuration of a peripheral section of a semiconductor integrated circuit according to a second embodiment of the present invention;
[0019] FIG. 7 is a plan view of the schematic configuration of a peripheral section of a semiconductor integrated circuit according to a third embodiment of the present invention; and
[0020] FIG. 8 is a plan view of a layout configuration of power supply protection elements shown in FIG. 7 .
DETAILED DESCRIPTION OF THE INVENTION
[0021] Exemplary embodiments of the present invention are explained in detail below with reference to the accompanying drawings. The present invention is not limited by the embodiments.
[0022] FIG. 1 is a plan view of the schematic configuration of a semiconductor integrated circuit according to a first embodiment of the present invention.
[0023] In FIG. 1 , an internal circuit 2 is formed on a semiconductor chip 1 . As the internal circuit 2 , for example, a signal processing circuit such as a logic circuit, a processor, a memory, an image sensor, or an ASIC can be formed.
[0024] Pad electrodes 4 are arranged in a peripheral section of the semiconductor chip 1 . A peripheral circuit 3 is arranged between the pad electrodes 4 and the internal circuit 2 . As the pad electrodes 4 , power supply pads 4 a and 4 b and input and output pads 4 c to 4 f can be provided. The power supply pad 4 a can deliver a low-potential power supply VSS. The power supply pad 4 b can deliver a high-potential power supply VDD. The input and output pads 4 c to 4 f can exchange signals input or output between the input and output pads 4 c to 4 f and the internal circuit 2 .
[0025] FIG. 2 is an enlarged plan view of an A section shown in FIG. 1 .
[0026] In FIG. 2 , on the peripheral circuit 3 , power supply cells 3 a and 3 b and input and output cells 3 c to 3 f are respectively arranged to correspond to the power supply pads 4 a and 4 b and the input and output pads 4 c to 4 f . In the power supply cells 3 a and 3 b , power supply protection elements that protect the internal circuit 2 from electrostatic discharge between power supply wires 7 and 8 can be provided. In the input and output cells 3 c to 3 f , electrostatic protection elements that protect the internal circuit 2 from electrostatic discharge between the input and output pads 4 c to 4 f and the power supply wires 7 and 8 can be provided. In the input and output cells 3 c to 3 f , input buffers that input signals, which are applied to the input and output pads 4 c to 4 f , to the internal circuit 2 , output buffers that output a signal, which is output from the internal circuit 2 , to the outside via the input and output pads 4 c to 4 f , level shifters that shift signals, which are input to and output from the internal circuit 2 , to a predetermined level, or the like can also be provided. For example, in the output cell 3 c , an inverter can be used as the input buffer. In the output cell 3 c , a first field effect transistor and a second field effect transistor can be used as the output buffer. The first field effect transistor is connected between the power supply wire 7 and the input and output pad 4 c . A gate potential of the first field effect transistor is controlled by a signal output from the internal circuit 2 . The second field effect transistor is connected between the power supply wire 8 and the input and output pad 4 c . A gate potential of the second field effect transistor is controlled by a signal output from the internal circuit 2 .
[0027] A spacer cell 5 is arranged in a space between the input and output cells 3 e and 3 f . Power supply protection elements 6 a to 6 c are respectively arranged in spaces among the input and output cells 3 c to 3 f . Power supply protection element 6 d is arranged in a space outside output cell 3 f . A power supply protection element 6 e is arranged on the spacer cell 5 . The power supply wires 7 and 8 are drawn around in the peripheral section of the semiconductor chip 1 to cross the power supply cells 3 a and 3 b , the input and output cells 3 c to 3 f , and the power supply protection elements 6 a to 6 e.
[0028] The power supply pad 4 a is connected to the power supply wire 7 and the power supply pad 4 b is connected to the power supply wire 8 . The power supply cells 3 a and 3 b and the power supply protection elements 6 a to 6 e are connected between the power supply wires 7 and 8 . The input and output pads 4 c to 4 f are connected to the internal circuit 2 respectively via the input and output cells 3 c to 3 f . Power supply protection elements 6 a to 6 e can include diode strings connected between the power supply wires 7 and 8 . An array pitch H 2 of the input and output pads 4 c to 4 e is desirably set larger than cell width H 1 of the input and output cells 3 c to 3 e to make it possible to insert the power supply protection elements 6 a to 6 b among the output cells 3 c to 3 f.
[0029] FIG. 3 is a diagram of an equivalent circuit of the A section shown in FIG. 2 . FIG. 4 is a diagram of an equivalent circuit of a diode string.
[0030] In FIG. 3 , a diode D 11 is provided in the power supply cell 3 a shown in FIG. 2 . A diode string S 1 is provided as a power supply protection element in the power supply cell 3 b shown in FIG. 2 . Diodes D 12 and D 13 are provided in the input and output cell 3 c . Diodes D 14 and D 15 are provided in the input and output cell 3 d . Diodes D 16 and D 17 are provided in the input and output cell 3 e . Diodes D 18 and D 19 are provided in the input and output cell 3 f . Diode strings S 2 to S 6 are respectively used as the power supply protection elements 6 a to 6 e . As shown in FIG. 4 , each of the diode strings S 2 to S 6 can be configured by connecting n (n is an integer equal to or larger than 2) diodes D 1 to Dn in series. Parasitic resistor R 1 and R 2 are present in the power supply wires 7 and 8 .
[0031] The power supply protection element of the power supply cell 3 b does not always have to be the diode string S 1 . A device other than the diode string S 1 such as a MOS transistor, a bipolar junction transistor (BJT), or an SCR can also be used.
[0032] The diode D 11 is connected between the power supply wires 7 and 8 such that a forward direction of the connection is a direction from a low potential side to a high potential side. The diodes D 12 , D 14 , D 16 , and D 18 are connected between the respective input and output pads 4 c to 4 f and the power supply wire 8 such that a forward direction of the connection is a direction from a low potential side to a high potential side. The diodes D 13 , D 15 , D 17 , and D 19 are connected between the respective input and output pads 4 c to 4 f and the power supply wire 7 such that a forward direction of the connection is a direction from a low potential side to a high potential side. The diode strings S 1 to S 6 are connected between the power supply wires 7 and 8 such that a forward direction of the connection is a direction from a high potential side to a low potential side. The number n of the diodes D 1 to Dn of each of the diode strings S 1 to S 6 is desirably set to be within a specification of standby leak between the power supply wires 7 and 8 .
[0033] When a surge voltage is applied to the power supply pads 4 a and 4 b , the diode D 11 of the power supply cell 3 a or the diode string S 1 of the power supply cell 3 b and the diode strings S 2 to S 6 provided among the input and output cells 3 c to 3 f function via the parasitic resistors R 1 and R 2 according to the polarity of the surge and perform electrostatic discharge (ESD) protection. In this case, a high protection ability can be expected compared with a protection ability obtained when the diode string S 1 alone of the power supply cell 3 b absorbs a surge between power supplies.
[0034] Protection of the internal circuit 2 is performed in several ways as explained below when a surge voltage is applied to the input and output pads 4 c to 4 f and flows to the power supply pads 4 a and 4 b . The input and output pad 4 f present in a position most distant from the power supply pads 4 a and 4 b among the input and output pads 4 c to 4 f is explained as an example.
[0035] When a surge having negative polarity is input to the input and output pad 4 f with the power supply pad 4 a set as a reference pad, the diode D 19 performs clamp operation and protects the internal circuit 2 . Because a discharge ability of the diode D 19 is high, the influence of the parasitic resistors R 1 and R 2 can be generally neglected.
[0036] When a surge having positive polarity is input to the input and output pad 4 f with the power supply pad 4 b set as a reference pad, the diode D 18 performs clamp operation and protects the internal circuit 2 . Because a discharge ability of the diode D 18 is high, the influence of the parasitic resistors R 1 and R 2 can be generally neglected.
[0037] When a surge having positive polarity is input to the input and output pad 4 f with the power supply pad 4 a set as a reference pad, the diode strings S 1 to S 6 connected to the power supply wires 7 and 8 via the diode D 18 perform clamp operation and protect the internal circuit 2 . In this case, compared with protection performed by only the diode string S 1 mounted on the power supply cell 3 b , when the diode strings S 2 to S 6 are mounted among the input and output cells 3 c to 3 f , the diode strings S 1 to S 6 can easily cooperatively operate during discharge, the influence of the parasitic resistors R 1 and R 2 can be reduced. Even the input and output pad 4 f present most distant from the power supply pad 4 a can perform sufficient ESD protection.
[0038] When a surge having negative polarity is input to the input and output pad 4 f with the power supply pad 4 b set as a reference pad, the diode strings S 1 to S 6 connected to the power supply wires 7 and 8 via the diode D 19 perform clamp operation and protect the internal circuit 2 . In this case, compared with protection performed by only the diode string S 1 mounted on the power supply cell 3 b , when the diode strings S 2 to S 6 are mounted among the input and output cells 3 c to 3 f , the diode strings S 1 to S 6 can easily cooperatively operate during discharge, the influence of the parasitic resistors R 1 and R 2 can be reduced. Even the input and output pad 4 f present most distant from the power supply pad 4 b can perform sufficient ESD protection.
[0039] The diode strings S 2 to S 6 are respectively used as the power supply protection elements 6 a to 6 e . This makes it unnecessary to provide a trigger circuit and makes it possible to improve a discharge ability and suppress an increase in a device area. Compared with responsiveness to a high-speed surge obtained when SCRs are used as the power supply protection elements 6 a to 6 e , it is possible to improve the responsiveness, improve uniform operation performance, and cause the power supply protection elements 6 a to 6 e to stably operate in parallel.
[0040] The power supply protection elements 6 a to 6 c are respectively arranged in the spaces among the input and output cells 3 c to 3 f . This makes it possible to reduce, even when a large surge current flows to the power supply wires 7 and 8 , the length of a discharge path for the surge current and suppress a voltage rise due to the parasitic resistors R 1 and R 2 of the power supply wires 7 and 8 . Therefore, it is possible to stably protect the internal circuit 2 from electrostatic discharge damage.
[0041] FIG. 5 is a plan view of a layout configuration of the power supply protection elements shown in FIG. 2 .
[0042] In FIG. 5 , diodes 11 to 13 connected in series are provided in the diode strings S 2 to S 6 shown in FIG. 3 . N wells W 1 to W 3 surrounded by a P-type high-concentration diffusion layer F 10 are respectively provided in the diodes 11 to 13 . The P-type high-concentration diffusion layer F 10 can configure a guard ring.
[0043] In the N well W 1 , an N-type high-concentration diffusion layer F 1 , a P-type high-concentration diffusion layer F 2 , and an N-type high-concentration diffusion layer F 3 are arranged side by side in a wiring direction of the power supply wires 7 and 8 . In the N well W 2 , a P-type high-concentration diffusion layer F 4 , an N-type high-concentration diffusion layer F 5 , and a P-type high-concentration diffusion layer F 6 are arranged side by side in the wiring direction of the power supply wires 7 and 8 . In the N well W 3 , an N-type high-concentration diffusion layer F 7 , a P-type high-concentration diffusion layer F 8 , and an N-type high-concentration diffusion layer F 9 are arranged side by side in the wiring direction of the power supply wires 7 and 8 . The N-type high-concentration diffusion layer F 1 , the P-type high-concentration diffusion layer F 4 , and the N-type high-concentration diffusion layer F 7 are desirably arranged on one straight line. The P-type high-concentration diffusion layer F 2 , the N-type high-concentration diffusion layer F 5 , and the P-type high-concentration diffusion layer F 8 are desirably arranged on one straight line. The N-type high-concentration diffusion layer F 3 , the P-type high-concentration diffusion layer F 6 , and the N-type high-concentration diffusion layer F 9 are desirably arranged on one straight line.
[0044] Wiring layers M 1 to M 6 are formed on the N wells W 1 to W 3 . The wiring layer M 1 is connected to the N-type high-concentration diffusion layer F 1 via contacts C 1 and connected to the P-type high-concentration diffusion layer F 4 via contacts C 4 . The wiring layer M 2 is connected to the P-type high-concentration diffusion layer F 2 via contacts C 2 . The wiring layer M 3 is connected to the N-type high-concentration diffusion layer F 3 via contacts C 3 and connected to the P-type high-concentration diffusion layer F 6 via contacts C 6 . The wiring layer M 4 is connected to the N-type high-concentration diffusion layer F 7 via contacts C 7 and connected to the P-type high-concentration diffusion layer F 10 via contacts C 10 . The wring layer M 5 is connected to the N-type high-concentration diffusion layer F 5 via contacts C 5 and connected to the P-type high-concentration diffusion layer F 8 via contacts C 8 . The wiring layer M 6 is connected to the N-type high-concentration diffusion layer F 9 via contacts C 9 and connected to the P-type high-concentration diffusion layer F 10 via contacts C 0 .
[0045] Wiring layers M 7 to M 9 are formed on the wiring layers M 1 to M 6 . The wiring layer M 7 is connected to the wiring layer M 4 via vias 32 and connected to the power supply wire 7 . The wiring layer M 8 is connected to the wiring layer M 2 via vias B 1 and connected to the power supply wire 8 . The wiring layer M 9 is connected to the wiring layer M 6 via vias B 3 and connected to the power supply wire 7 .
[0046] In the embodiment shown in FIG. 5 , a configuration in which the diodes 11 to 13 are connected in series in three stages is explained as an example. However, to increase the number of stages of diodes connected in series, the diodes 11 to 13 shown in FIG. 5 only have to be repeatedly arranged in a direction orthogonal to the power supply wires 7 and 8 . Therefore, it is possible to increase the number of stages of the diodes connected in series without increasing the width of the power supply protection elements 6 a to 6 d shown in FIG. 2 . Even when the spaces among the input and output cells 3 c to 3 f are narrow, it is possible to respectively arrange the power supply protection elements 6 a to 6 d in the spaces among the input and output cells 3 c to 3 f.
[0047] The wiring layers M 7 to M 9 can be formed on a wiring layer different from a wiring layer on which the power supply wires 7 and 8 shown in FIG. 2 are formed. However, the wiring layers M 7 to M 9 can also be formed on a wiring layer same as the wiring layer on which the power supply wires 7 and 8 shown in FIG. 2 are formed.
[0048] FIG. 6 is a plan view of the schematic configuration of a peripheral section of a semiconductor integrated circuit according to a second embodiment of the present invention.
[0049] In FIG. 6 , pad electrodes are arranged in zigzag in a peripheral section of a semiconductor chip. As the pad electrodes, power supply pads 14 a and 14 b and input and output pads 14 c to 14 f are provided. Power supply cells 13 a and 13 b and input and output cells 13 c to 13 f are respectively arranged to correspond to the power supply pads 14 a and 14 b and the input and output pads 14 c to 14 f . Power supply protection elements 16 a to 16 c are respectively arranged in spaces among the input and output cells 13 c to 13 f . Power supply wires 17 and 18 are drawn around in the peripheral section of the semiconductor chip to cross the power supply cells 13 a and 13 b , the input and output cells 13 c to 13 f , and the power supply protection elements 16 a to 16 d.
[0050] The power supply pad 14 a is connected to the power supply wire 17 . The power supply pad 14 b is connected to the power supply wire 18 . The power supply cells 13 a and 13 b and the power supply protection elements 16 a to 16 d are connected between the power supply wires 17 and 18 . The input and output pads 14 c to 14 f are connected to an internal circuit respectively via the input and output cells 13 c to 13 f . The power supply protection elements 16 a to 16 d can include diode strings connected between the power supply wires 17 and 18 . An array pitch H 12 of the input and output pads 14 c to 14 f is desirably set larger than cell width H 11 of the input and output cells 13 c to 13 f to make it possible to insert the power supply protection elements 16 a to 16 c among the input and output cells 13 c to 13 f . The diode D 11 shown in FIG. 3 can be provided in the power supply cell 13 a . In the power supply cell 13 b , the diode string S 1 shown in FIG. 3 can also be provided or a device other than the diode string S 1 such as a MOS transistor, a BJT, or a SCR can also be provided.
[0051] The power supply protection elements 16 a to 16 c are respectively arranged in the spaces among the input and output cells 13 c to 13 f . This makes it possible to stably protect the internal circuit from electrostatic discharge damage while suppressing an increase in a device area even when the pad electrodes are arranged in zigzag.
[0052] FIG. 7 is a plan view of the schematic configuration of a peripheral section of a semiconductor integrated circuit according to a third embodiment of the present invention.
[0053] In FIG. 7 , pad electrodes are arranged in a peripheral section of a semiconductor chip. As the pad electrodes, power supply pads 24 a and 24 b and input and output pads 24 c to 24 f are provided. Power supply cells 23 a and 23 b and input and output cells 23 c to 23 f are respectively arranged to correspond to the power supply pads 24 a and 24 b and the input and output pads 24 c to 24 f . A spacer cell 25 is arranged in a space between the input and output cells 23 e and 23 f . Power supply protection elements 26 c to 26 f are respectively provided in the input and output cells 23 c to 23 f . Power supply wires 27 and 28 are drawn around in the peripheral section of the semiconductor chip to cross the power supply cells 23 a and 23 b and the input and output cells 23 c to 23 f . The power supply protection elements 26 c to 26 f can be respectively provided in the input and output cells 23 c to 23 f to be arranged between the power supply wires 27 and 28 . The power supply protection elements 26 c to 26 f can also be arranged to overlap the power supply wires 27 and 28 .
[0054] The power supply pad 24 a is connected to the power supply wire 27 . The power supply pad 24 b is connected to the power supply wire 28 . The power supply cells 23 a and 23 b and the power supply protection elements 26 a to 26 f are connected between the power supply wires 27 and 28 . The input and output pads 24 c to 24 f are connected to an internal circuit respectively via the input and output cells 23 c to 23 f . The power supply protection elements 26 c to 26 f can include diode strings connected between the power supply wires 27 and 28 . An array pitch H 21 of the input and output pads 24 c to 24 e is desirably set to correspond to cell width H 22 of the input and output cells 23 c to 23 d . The diode D 11 shown in FIG. 3 can be provided in the power supply cell 23 a . In the power supply cell 23 b , the diode string S 1 shown in FIG. 3 can be also be provide or a device other than the diode string S 1 such as a MOS transistor, a BJT, or a SCR can also be provided.
[0055] The power supply protection elements 26 c to 26 f are arranged between the power supply wires 27 and 28 . This makes it unnecessary to provide a space between the input and output cells 23 e and 23 f and makes it possible to stably protect the internal circuit from electrostatic discharge damage while suppressing an increase in a device area.
[0056] FIG. 8 is a plan view of a layout configuration of the power supply protection elements shown in FIG. 7 .
[0057] In FIG. 8 , the diode strings included in the power supply protection elements 26 c to 26 f shown in FIG. 7 include diodes 21 to 23 connected in series. N wells W 11 to W 13 surrounded by a P-type high-concentration diffusion layer F 17 are respectively provided in the diodes 21 to 23 . The P-type high-concentration diffusion layer F 17 can configure a guard ring.
[0058] In the N well W 11 , a P-type high-concentration diffusion layer F 11 and an N-type high-concentration diffusion layer F 12 are arranged side by side in a direction orthogonal to the power supply wires 27 and 28 . In the N well W 12 , a P-type high-concentration diffusion layer F 13 and an N-type high-concentration diffusion layer F 14 are arranged side by side in the direction orthogonal to the power supply wires 27 and 28 . In the N well W 13 , a P-type high-concentration diffusion layer F 15 and an N-type high-concentration diffusion layer F 16 are arranged side by side in the direction orthogonal to the power supply wires 27 and 28 .
[0059] Wiring layers M 11 to M 14 are formed on the N wells W 11 to W 13 . The wiring layer M 11 is connected to the P-type high-concentration diffusion layer F 11 via contacts C 11 . The wiring layer M 12 is connected to the N-type high-concentration diffusion layer F 12 via contacts C 12 and connected to the P-type high-concentration diffusion layer F 13 via contacts C 13 . The wiring layer M 13 is connected to the N-type high-concentration diffusion layer F 14 via contacts C 14 and connected to the P-type high-concentration diffusion layer F 15 via contacts C 15 . The wiring layer M 14 is connected to the N-type high-concentration diffusion layer F 16 via contacts C 16 and connected to the P-type high-concentration diffusion layer F 17 via contacts C 17 .
[0060] The power supply wires 27 and 28 are formed on the wiring layers N 11 to M 14 . The power supply wire 27 is connected to the wiring layer M 14 via vias B 12 . The power supply wire 28 is connected to the wiring layer N 11 via vias B 11 .
[0061] In the embodiment shown in FIG. 8 , a configuration in which the diodes 21 to 23 are connected in series in three stages is explained as an example. However, to increase the number of stages of diodes connected in series, the diodes 21 to 23 only have to be repeatedly arranged in a direction orthogonal to the power supply wires 27 and 28 .
[0062] In the embodiment explained above, a method of arranging the input and output cells not to overlap the input and output pads is explained. However, the present invention can also be applied to a structure in which the input and output cells are arranged under the input and output pads.
[0063] Additional advantages and modifications will readily occur to those skilled in the art. Therefore, the invention in its broader aspects is not limited to the specific details and representative embodiments shown and described herein. Accordingly, various modifications may be made without departing from the spirit or scope of the general inventive concept as defined by the appended claims and their equivalents.
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A semiconductor integrated circuit includes: an internal circuit formed on a semiconductor chip, power being supplied thereto via a first power supply wire and a second power supply wire; input and output pads that exchange an input signal or an output signal with the internal circuit; input and output cells including first electrostatic protection elements that protect the internal circuit from electrostatic discharge between the input and output pads and the first or second power supply wire; and second power supply protection elements provided adjacent to the input and output cells and including diode strings connected between the first power supply wire and the second power supply wire.
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BACKGROUND OF THE INVENTION
The subject invention relates to a method for generating a mailpiece. More particularly, it relates to a host computer particularly suited for control of a mailing system.
Mailing machines are utilized for printing, collating and inserting various documents into an envelope. Typically, feeders deposit documents onto a moving conveyor belt, and the various documents are collected, aligned and inserted into an envelope. Conventionally, the printing means, feeding means, collecting means, aligning means, and inserting means are situated along a single document path. The marketplace today requires that mailpieces should be generated as rapidly as possible, and it should be apparent that the use of a single document path is a time consuming process.
Many methods for control of a mailing system with a single document path have been developed. While these methods can work quite well, these solutions have certain inadequacies which limit the use of known control methods with a mailing system having multiple document paths. For example, it is difficult to track the number of active mailpieces in the mailing system. In particular, it is an arduous task to keep global track of the mailpiece contents. Still further, it is burdensome to generate a mailpiece in a high speed mailing system without providing an address document coded with the mailpiece contents. None of the heretofore known methods for control of a mailing system teach a method for generating a mailpiece in a manner to globally track mailpieces along multiple document paths thereby increasing mailpiece integrity.
DEFINITION
As used herein, the following terms have the meaning set forth.
Segment: A data element including identification of the motor, solenoid, or sensor effected by the segment command (if any); a command to be executed by the motion control processor during the segment, and any information required for execution of the segment command.
Profile: A sequence of segments whose execution by a motion control processor controls a mechanical system to carry out a corresponding mechanical function.
Mailpiece attribute: a data element defining a physical characteristic of a mailpiece generated by a mechanical system. P Job attribute: a data element defining instructions for system wide handling of all pieces in a job run.
SUMMARY OF THE INVENTION
It is an object of the invention to provide an improved method for generating a mailpiece in a high speed mailing system without printing codes on each mailpiece.
It is still further an object of the invention to provide a method for generating a mailpiece in a mailing system having multiple document paths.
It is still further an object of the invention to provide a method for logically tracking mailpiece production as the physical mailpiece moves from mechanical module to mechanical module.
It is a further object of the invention to provide a software architecture such that the base control software for determining the motion control requirements for each mailpiece will be the same for each mechanical module.
These and other objects and advantages as will appear hereinafter are attained in a novel method for generating a mailpiece in a mailing system having multiple document paths. A table will be generated for tracking each mailpiece in the mailing system. Attribute data relating to a mailpiece will be stored in a memory while job data relating to a mailing job will also be stored in the memory. A sequence builder process will look at the attribute data and determine the motion profiles that are required to ensure the mailpiece obtains the desired attributes. The sequence builder then commands execution of the motion profiles.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic block diagram of an apparatus for generating a mailpiece in accordance with the subject invention.
FIG. 2 is a schematic block diagram of an alternate embodiment of the apparatus for generating a mailpiece in accordance with the subject invention.
FIG. 3 is a representation of relationships between tasks performed by the host computer used in the apparatus of FIG. 1.
FIGS. 4a, 4b, and 4c show a flow diagram for the mailpiece builder task shown in FIG. 3.
FIG. 5 is a schematic block diagram of a mailing system having multiple document paths.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring to FIG. 1, there is shown a mailing system 1 on which the present invention may be employed. The mailing system 1 includes a host processor 10 which is provided with a multitasking operating system program. Mailing system 1 has a central control process 2 and a sequence builder process 3 running on the host processor 10. A motion control processor 4 is connected to host processor 10 through communications link 12 for transmission of messages between host processor 10 and motion control processor 4. Communications link 12 may be any suitable communications link having the necessary communications capacity for the subject invention. Host processor 10 is preferably an Intel 80386 processor and will determine the motion control requirements to be communicated to motion control processor 4. A preferred embodiment of the motion control processor 4 is described in commonly assigned, co-pending U.S. application Ser. No. 08/327,246 filed Oct. 24, 1994, which is hereby incorporated by reference.
Interface and drivers 5 comprises circuitry which converts the digital output of motion control processor 4 into control signals having the proper waveform and timing to control a mailing system. Details of the design of interface and drivers 5 will of course depend upon the processor selected as motion control processor 4. Such design would be a matter of routine for a person of ordinary skill in the art and need not be discussed further herein for an understanding of the subject invention. Generally, in the subject invention, interface and drivers 5 will output control signals to DC motors, stepper motors, and solenoids and receive status signals from sensors in the mailing system.
FIG. 2 shows an alternative embodiment of a mailing system 1 in accordance with the subject invention. In this configuration, the motion control requirements are handled by a motion control process 6 which resides in host processor 10. This flexible architecture enables the host processor 10 to implement the subject invention in a single processor environment yet maintain mailpiece integrity without the need for a dedicated motion control processor.
FIG. 3 shows the software architecture for host processor 10. Central control process 2 includes the mailpiece coordinator task 20 which tracks the processing order of a mailpiece in the mailing system and error handling task 40 which maintains mailpiece integrity in the event the mailing system experiences a fault. The sequence builder process 3 includes at least one mailpiece builder task 30 which determines motion control requirements for each mailpiece.
The mailpiece coordinator task 20 generates a table 24 for each mailpiece in the mailing system. The table 24 includes the mailpiece attributes which are required for the mailpiece. Mailpiece attributes used in a preferred embodiment of the subject invention are set forth in Table 1.
TABLE I______________________________________MAILPIECE ATTRIBUTE COMMENT______________________________________Printer Tokens Identifies specific document pages.Mailpiece Number The tracking number for the mail- piece.Total Pages Number of pages in a document.Document Destination Output destination for a printed document.Fold Type C or Z fold.Pre-Print Feeder Number Feeder to use for the pre-printed sheets.BRE Feeder Number Feeders to use for feeding reply envelopesSeal Piece Determines whether or not to seal a mailpiece.Dry Time The dry time to use for the mail- piece.Envelope Printing TRUE if envelope is being printed on. FALSE if the envelope is fed without printing.Print Postage Indicates whether an indicia is needed for the mailpiece. If so, the postage value is indicated.Stack Location Destination of complete mailpiece.Stack Offset TRUE if offsetting piece in stacker. Otherwise, FALSE.______________________________________
In addition to the table 24, the mailpiece coordinator task 20 stores a job attribute header 22 for information that applies to all mailpieces in the job run. The job attributes 22 would define the regeneration algorithm in the event of a mechanical fault, order of output documents, and maximum number of mailpieces allowed in the system. The number of pieces to place in the mail output bin may be specified on a per job basis using the job attributes 22 or on a per mailpiece basis using the mailpiece attributes.
Referring to FIG. 3, when the mailpiece coordinator task 20 receives a CREATE PIECE command, the mailpiece coordinator task 20 determines whether the created mailpiece will be the first mailpiece in a job run. If it is the first mailpiece, the mailpiece coordinator task 20 will update the mailpiece table 24 with mailpiece attributes and will also update the job attributes data store 22; both data elements accompany the CREATE PIECE command. If it is not the first mailpiece, the mailpiece coordinator task 20 will only update the mailpiece table 24. Next, the mailpiece coordinator task 20 transmits the mailpiece information for the received mailpiece to the mailpiece builder task 30 which determines the motion control requirements for each mailpiece. In a mailing system with a plurality of mechanical modules, the host computer 10 runs at least one mailpiece builder task 30 for each mechanical module. Each of the mailpiece builder tasks 30 that represent a mechanical module in the mailing system will execute the same software. The mailpiece attributes 24 received and acted upon by each mailpiece builder task 30 will differ for each mechanical module. Therefore, while the same software can drive each mailpiece builder task 30, the data associated with the plurality of tasks will differ. In this manner, the software architecture allows the host computer 10 to logically track a mailpiece through the mechanical modules of the mailing system.
FIGS. 4a, 4b, and 4c show a flow diagram of the operation of mailpiece builder task 30. At step 60, in response to mailpiece information being transferred from the mailpiece coordinator task 20, the mailpiece builder task 30 retrieves the mailpiece information received from the mailpiece coordinator 20. Decision block 62 determines whether the mailpiece information includes a READY signal from the next logical mailpiece builder task representing a subsequent mechanical module. If the mailpiece builder task receives a READY signal, decision block 100 determines whether all mailpiece attributes are present before proceeding to the next step. At step 64, mailpiece attributes will be passed to the next logical mailpiece builder task. In the subject invention, if a subsequent mechanical module does not report a problem to its corresponding mailpiece builder task, and the subsequent mechanical module is notified by the profile that the piece has been passed on, its corresponding mailpiece builder task will indicate to the mailpiece builder task for a preceding mechanical module that the subsequent mechanical module is ready to receive data.
Decision block 66 determines whether the mailpiece information consists of mailpiece attributes 24 from the preceding mailpiece builder task. If so, the mailpiece builder task at step 68 retrieves the motor, sensor, and solenoid profiles which correspond to the mailpiece attributes 24. At step 70, the mailpiece builder task 30 will set flags in the profiles to the motion control processor 4. Typically, all profiles will be downloaded on power up or when motion control processor 4 is otherwise initialized. However, it is within the contemplation of the subject invention that profiles can be downloaded during operation of the mailing system to change the operating parameters of the system. Decision block 102 determines whether the motion control processor 4 is ready to receive mailpiece attributes data. If so, the mailpiece builder task 30 at step 104 transfers the mailpiece attributes to the motion control processor 4.
Decision block 72 determines whether the mailpiece information consists of a mechanical module command. The mailpiece coordinator 20 uses the mechanical module command to inform the module that a downstream error has occurred. At step 73, the mailpiece builder brings mailpieces in the mechanical module to rest and cancels any outstanding profiles. After the downstream error is cleared at step 74, the mailpiece coordinator sends a mechanical module command to restart the profiles at step 75, which were previously canceled.
Decision block 76 determines whether the mailpiece information consists of a query command requesting the mailpiece builder 30 to query the motion control processor 4 to determine if a mailpiece or mailpieces are present in the mechanical module. At step 78, the mailpiece builder requests sensor status from the motion control processor 4. Upon receiving the sensor data, the mailpiece builder 30 determines if paper is present, and at step 80 transfers the sensor status to the mailpiece coordinator 20.
Referring to FIG. 4b, decision block 82 determines whether the mailpiece information consists of an error message from a preceding mechanical module. In the subject invention, errors propagate through the mailpiece system either through an error message from a profile or a notification from the mailpiece coordinator 20 commanding the mailpiece builder 30 to bring mailpieces in the mechanical module to a stop and cancel profiles. If the mailpiece builder 30 receives an error message, at step 84, the mailpiece builder 30 will notify the mailpiece coordinator 20 of an error, then, at step 86, command the motion control processor 4 to cancel outstanding profiles. Next, at step 106, the mailpiece builder 30 will start error handler profiles and, at step 108, set error flags in the motion controller 4.
Decision block 88 determines whether the mailpiece information contains a profile complete status from the motion control processor 4. If the profile complete status is received from the motion control processor 4, decision block 110 determines whether the physical mailpiece has started to move into the next mechanical module. If at step 112 the profile hand-off is complete for the mechanical module which will receive the mailpiece, and if at step 114 there are no previously reported errors, the mailpiece builder task 30 sends a READY signal to mailpiece builder task for the preceding mechanical module at step 118. If the mailpiece attributes are present at step 120, the mailpiece builder task transmits commands to select and initiate the appropriate profiles to the motion control processor at step 122.
Referring to FIG. 4c, if the profile hand-off has started, decision block 90 determines whether the mailpiece builder task 30 represents the last logical mailpiece builder task required to complete the mailpiece. If the mailpiece is complete, at 92, the mailpiece builder task transmits a piece complete message to the mailpiece coordinator 20. If the mailpiece is incomplete, decision block 94 determines whether the next logical mailpiece builder task is ready to receive the mailpiece. If the next mailpiece builder task is busy, the mailpiece builder task at 98 waits until the software task is ready. At 96, the mailpiece builder transfers mailpiece attributes to the next logical mailpiece builder task.
To assist those skilled in the art in understanding how the subject invention generates a mailpiece, there is shown a multiple document path mailing system 150 on which the present invention may be employed. System 150 includes the following mechanical modules: document printer 152, pre-print feeder 154, reply envelope feeder 156, accumulator 160, folder 162, envelope printer 164, dry station 166, flapper 168, inserter 170, moistener 172, sealer 174, and stacker 176. Set forth below, by way of example only, is pseudocode such as could be used to implement the method of the present invention in system 150.
______________________________________FOR Mailpiece Coordinator TaskIF CREATE PIECE Received by Mailpiece CoordinatorWrite mailpiece attributes into a table;Pass Document Attributes to tasks for mechanicalmodules at the beginning of each document path;FOR first document pathPass Document Attributes to the DocumentPrinter mailbuilder task;FOR second document pathPass Preprint Attributes to the Preprintmailbuilder task;FOR third document pathPass Reply Envelope Feeder Attributes totheReply Envelope Feeder mailbuilder task;FOR fourth document pathPass Envelope Attributes to the EnvelopePrinter mailbuilder task;Monitor output from mailbuilder tasks;END IF.IF PIECE COMPLETE message received from theStackerDelete mailpiece attributes from table;END IF.END.FOR each Mailpiece Builder TaskStudy mailpiece attributes received from mailpiececoordinator or another mailpiece builder task;Determine profiles required by the motion controlprocessor;Issue profile commands to the motion control processoronreceipt of attributes;IF Profile.sub.-- Handoff.sub.-- Done received, thenTransmit READY signal;CASE Accumulator: send READY to document printer, and pre-print feederCASE Dry Station: send READY to envelope printer;Case Flapper: send READY to dry station;Case Folder: send READY to accumulator andreply envelope feeder;CASE Inserter: send READY to Folder andFlapper;CASE Moistener: send READY to Inserter;CASE Sealer: send READY to Moistener;CASE Stacker: send READY to Sealer;END IF.IF Profile handoff started and all attributes presentIF (Document printer, Pre-print feeder, Replyenvelope feeder, Envelope printer, Dry station,Flapper, Folder, Moistener, or Sealer) Transfer attributes to the next logical task; ELSE IF Accumulator Merge attributes from Documentprinter, Pre-print feeder, and Reply envelope feeder; Transfer attributes to the next logical task; ELSE IF Inserter Merge attributes from Folder and Flapper; Transfer attributes to the next logical task; ELSE IF Stacker Send PIECE COMPLETE message to mailpiece coordinator; END IF.END IF.END.______________________________________
The foregoing description of the preferred embodiment of the present invention has been presented for purposes of illustration and description. It is not intended to be exhaustive or to limit the invention to the precise form disclosed. Obviously, many modifications and variations will be apparent to practitioners skilled in this art. The embodiment was chosen and described in order to best explain the principles of the invention and its practical application thereby enabling others skilled in the art to understand the invention for various embodiments and with various modifications as are suited to the particular use contemplated. It is intended that the scope of the invention be defined by the accompanying claims and their equivalents.
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A table will be generated for tracking each mailpiece in a mailing system having multiple document paths. Attribute data relating to a mailpiece will be stored in a memory while job data relating to a mailing job will also be stored in a memory. A sequence builder process will look at the attribute data and determine the motion profiles that are required to ensure the mailpiece obtains the desired attributes. The sequence builder then commands execution of the motion profiles.
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CROSS-REFERENCE TO RELATED APPLICATIONS
This application is a 35 U.S.C. §371 National Phase Entry Application from PCT/EP2009/062942, filed Oct. 6, 2009 (published as WO 2011042046), and designating the United States.
TECHNICAL FIELD
The present invention relates to a solution for handling customer activity when connecting to a wireless communication network and in particular for statistics of customer activity using the network.
BACKGROUND
The use of packet based communication in wireless networks extends the use of wireless devices into packet based networks such as Internet or operator specific networks and services available in these networks. There is an interest from operators or service providers to provide increasingly better service to the users and to offer added functionality and ease the use of services and increase availability of the networks for the users.
With state-of-the-art technology such as Evolved Packet Core, SIM based authentication, Deep Packet Inspection and Policy and Charging Control (PCC), mobile operators can gather potentially extensive information about each subscriber, e.g. protocols they use, URI's or sites on Internet they visit, their identity. This information can with some limitations be transformed into end-user interest profiles. The mobile operator may also have other information of its subscribers, e.g. interest profiles gathered through end-user surveys or queries, which may complement in building the end-user interest profiles.
So far operators have been able to use the information about the usage of services to differentiate the subscriber's charging or to control the access in different ways (e.g. stop access to certain sites or services, control the bandwidth etc).
PCC is defined to work in this direction only. It has however been difficult to address the growing market for subscriber usage and behavior analysis and extend the business beyond traditional use cases and find new business opportunities, e.g. sell usage/behavior information to third party companies.
SUMMARY
It is therefore an object of the present invention to provide solutions that addresses these problems.
The solution according to the present invention enables mobile operators to take advantage of having authenticated users and being able to monitor what users do by Deep Packet Inspection (DPI). The gathered information is processed and stored in a new entity Subscriber Usage Profile Repository (SUPR), which is indexed by IMSI and currently used IP address(es). The IP address(es) in the SUPR are updated whenever changes occur from user activities, i.e. attach/detach, bearer activations/deactivations, or IP address changes for other reasons. If the user is connected to Internet via an IPv4 NAT or Firewall, the assigned public IP address and optionally port number may also be stored in the SUPR.
Service providers on Internet may then in real-time access the SUPR. When, for example, someone is accessing a web-server, the web-server may by using the source IP address in the HTTP-request, retrieve user profile information from the SUPR and assemble an HTTP-response with content based on the user's interest profile. This may be as simple as adding advertisements on the HTML page according to the interest of the user, or it may be any kind of personalization or content tailoring based on the user profiles.
An alternative for the operator to use the SUPR information, is to sell subscriber interest profiles to service providers. For example: “provide me with a list of persons (name, address, email address) which have accessed any of these 10 motor-web-sites on Internet the last 6 months”. The provisioning of the information may be manual and offline, but it may also be automated and provided to the service provider in a similar way as for the real-time alternative above, e.g. XML based request/response to the SUPR server.
The mobile operator may then charge service providers for the information they have received. This is a new revenue stream for the mobile operator which may increase the ARPU even for “bit pipe providers”.
The revenue for a specific user is also to some extent related to total bandwidth used by the user. That is, a user consuming more bandwidth is likely to visit more web-sites on Internet and hence may give the mobile operator a bigger income from usage profiles.
In short, thanks to the possibility of selling usage profiles, even for a mobile broadband subscriber paying a flat monthly fee−higher usage=higher revenue!
This is provided in a number of aspects in which a first is a method in a core part of a wireless communication network. The method comprises the steps of:
receiving user statistics from deep packet inspection; storing user information comprising user statistics together with user identity information; receiving a request from an application server, relating to an IP address and requesting user information; and providing at least part of stored user information to the application server.
The method may further comprise the steps of:
receiving an attachment request from a user equipment, i.e. UE, and assigning at least one IP address to the UE; updating a policy and charging rules function, i.e. PCRF, with at least one IP address assigned for the UE; updating a subscriber usage profile repository, i.e. SUPR, with information relating to the UE; enabling deep packet inspection of data relating to the UE and assigned IP address and retrieving user statistics using a Policy and Charging Enforcement Function, i.e. PCEF; reporting user statistics information to the PCRF; forwarding user statistics information to the SUPR; providing user information deducible from the user statistics information and/or the user identity information to at least one application server requesting such information; and storing identity information relating to application servers.
The user statistics may comprise at least one of visited URI's by the UE, application used by the UE, protocols used by the UE, and type of services used by the UE. The SUPR may store information related to an identifiable UE. The deducible user information may be provided in an XML format. A network address translation unit provides information about relation between public and private IP addresses to the SUPR.
The method may further comprise a step of authenticating the application server before providing user information to the application server. The method may further comprise a step of updating the PCRF and SUPR if IP address is changed for the UE. The method may further comprise a step of handling multiple IP addresses.
Another aspect of the present invention is provided, a node in wireless communications network. The node comprising a processor, a computer readable storage medium, and a communication interface. The processor may be arranged to execute instructions sets stored in the storage medium, using the communication interface, for:
receiving an attachment request from a user equipment, i.e. UE, and assigning at least one IP address to the UE; updating a policy and charging rules function, i.e. PCRF, with at least one IP address assigned for the UE; updating a subscriber usage profile repository, i.e. SUPR, with information relating to the UE; enabling deep packet inspection of data relating to the UE and assigned IP address and retrieving user statistics using a Policy and Charging Enforcement Function, i.e. PCEF; reporting user statistics information to the PCRF; forwarding user statistics information to the SUPR; providing user information deducible from the user statistics information and/or the user identity information to application servers requesting such information; and storing identity information relating to application servers.
Yet another aspect of the present invention is provided, a business method related to a communications network. The business method may comprise the steps of:
storing user information relating to an identifiable user and user usage profile; receiving a request relating to the user information from an external application server comprising an IP address; providing at least past of the user information to the external application; and charging for the providing of the user information.
The business method may further comprise a step of comparing user ID connected to IP address with recent requests.
Still another aspect of the present invention is provided, a core network in a wireless communication network. The core network may comprise a gateway and a policy and charging rules function entity. The gateway may be arranged to provide communicative connection with a user equipment, i.e. UE, to provide access to a packet data network for the UE, provide deep packet inspection, i.e. DPI, of data packets passing through the gateway, determine user statistics from the DPI, and provide user statistics to the policy and charging rules function entity, i.e. PCRF. The network may further comprise a subscriber usage profile repository receiving user statistics information from the PCRF and providing access to the subscriber usage information to application servers requesting such information. The gateway may be one of a PGW or a GGSN and the network may further comprise at least one of network address translation entity and/or firewall.
The invention enables mobile operators to take advantage of having authenticated users and being able to monitor what users do by Deep Packet Inspection (DPI). A new revenue stream can be created by offering this information in form of user interest profiles and/or user identities to third party enterprises. The third party enterprise retrieves this information in real time using the IP address of the user.
The invention may increase the market potential for CPG's equipped with the proposed functionality. It may also increase the potential for Fixed Mobile Convergence and using DPI enabled GWs also for fixed accesses.
BRIEF DESCRIPTION OF THE DRAWINGS
In the following the invention will be described in a non-limiting way and in more detail with reference to exemplary embodiments illustrated in the enclosed drawings, in which:
FIG. 1 illustrates schematically a network according to the present invention;
FIG. 2 illustrates schematically a method according to the present invention;
FIG. 3 illustrates schematically in a block diagram a device according to the present invention; and
FIG. 4 illustrates schematically in a signaling diagram an overall process according to the present invention.
DETAILED DESCRIPTION
In FIG. 1 reference numeral 100 denotes a core network configuration according to the present invention. The network comprises a gateway 103 , e.g. a Packet Data Network GW (PGW) connected to a Policy and Charging Rules function (PCRF) entity 104 . The gateway is also connected to an access network 102 in turn communicating wirelessly 110 with user equipment 101 . Furthermore, the network comprises a Subscription Profile Repository (SPR) 105 and a Subscriber Usage Profile Repository (SUPR) 106 . Both the SPR and the SUPR are connected to the PCRF and furthermore connected to each other. Both the PGW and the SUPR are connected to a packet data network 107 (PDN), e.g. Internet. Optionally a Network Address Translation (NAT) entity 111 is located between the PGW and the PDN. It should be noted that the core network 100 comprise further nodes not shown such as support gateway, e.g. SGSN, mobility node, e.g. Mobility Management Entity (MME), and so on. Furthermore, routers, switches, cabling, and other network communication enabling devices are used to maintain physical links between nodes in the network(s). A firewall (FW) 112 may be located between the SUPR and the PDN in order to provide a secure location of the SUPR. Application Servers (APS) 108 may be connected to the PDN and provide services to UEs connected to the PDN via the access network.
In the present invention it is provided a solution for handling user statistics and providing information about these statistics to application servers connected to the PDN. The process according to the present invention may be described as follows with reference to FIGS. 1 and 2 :
201 . A new user attaches to the mobile operators network and one or more IP addresses are assigned to the UE. The PCRF is updated with the assigned IP address(es) as part of the ‘Create IP-CAN Session’ or ‘IP-CAN Session Modification’. The SUPR is immediately updated by the PCRF when it becomes aware of any changes of IP addresses for the UE. For operators assigning IPv4 addresses to their subscribers, but not using public IPv4 addresses, a NAT or Firewall doing address translations may be placed at the boarder to Internet. The NAT/Firewall would then update the SUPR each time a mapping is created or deleted between private and public IPv4 addresses. The IPv4 port number may also be part of and significant in this mapping and updated to the SUPR.
202 . Deep Packet Inspection (DPI) is enabled for configured PDNs, e.g. Internet. A Policy and Charging Enforcement Function (PCEF) in the PGW has an extended function for collecting usage statistics e.g. URI's, sites visited on Internet, protocols used, or anything else that can be deduced from inspecting the IP packets generated by the user, and associated to a specific interest. The usage statistics is reported over a suitable interface, e.g. an extended Gx interface 113 , to the PCRF, which forwards the information to the SUPR together with the IMSI for subscriber identity. The information in processed and stored in the SUPR as ‘user profiles’, searchable by the users currently used IP address(es), and for convenient use by service provider's application servers on Internet.
203 . The UE starts to access a web-server on Internet; the web-server where the provider has an agreement with one or more mobile operators. From the source IP address in the HTTP-request the web-server knows which and if the request originates from a mobile operator which it has an agreement on user profiles with.
204 . If a web-server receives a request from an IP address belonging to an operator with which the web-server company has an agreement, a ‘user profile request’ is sent to the SUPR server of that operator. Parameters in the request include user identity of the web-server company and its password according to business agreement between the Service Provider and the Mobile Operator. Parameters may also include parameters which indicate different levels of requested information, different interest areas etc, e.g. user profiles of “type A” or “type B” or with/without the users identity (MSISDN, Name, Address, e-mail address etc). A ‘user profile response’ is returned to the web-server with requested information if any information was found. The information is preferably provided on XML-format. The SUPR-node maintains charging information what profiles have been provided to the service provider for later charging of the service provider.
205 . The web-server receives the user profiles and uses the information to process the HTTP-request and assemble an HTML page which is returned to the UE in a HTTP-response. Advertisement targeting the users special interest may e.g. be included in the HTML-page. If requested and received, the web-server may also use the identity of the user of its web-site for any later relational marketing campaigns or any statistical purposes.
Regularly, e.g. on a monthly basis, the mobile operator bills the service providers it has agreements with.
The user interest profiles that are stored in the SUPR, does in this description above originate from DPI. However they may also originate from customer inquiries, i.e. forms directly filled in by subscribers. The identity information such as name, address, e-mail address, phone numbers, etc, should originate from the subscription information the mobile operator has from each subscriber.
FIG. 3 shows a node in the infrastructure network operating parts of the method according to the present invention. This node may be for instance a gateway node, e.g. PGW or GGSN. The node comprises a processing unit 301 , e.g. a microprocessor or Digital Signal Processor (DSP), arranged to execute instruction sets stored in a memory unit 302 of volatile and/or non-volatile type. The memory unit is arranged as a computer readable storage medium. Furthermore, the node comprises at least one communication interface 304 and optionally a user interface 303 . The instruction sets are configured to execute parts of the method of the present invention and the role of the node is shown in relation to FIG. 2 but will also be described in relation to FIG. 4 below. It should be appreciated that alternatively the processing unit may be arranged to execute hardware instructions sets: the processing unit may be an Application Specific Integrated Circuit (ASIC), Field Programmable Gate Array (FPGA), or similar device.
FIG. 4 shows an example of the signaling process for a UE attaching to the network, the core network monitoring with DPI the activities of the UE, and providing information to Application Server(s) located on the PDN. The UE and PGW communicate bearer establishment messages 401 , via the access network. The PGW in turn transmits 402 IP-CAN Session establishment communications to the PCRF with IMSI and IP address information; the PCRF in turn forwards 403 this information to the SUPR. The SUPR communicates a Subscriber Info Request 404 with the Subscriber database (SPR) with information relating to IMSI; the SPR in turn responds with a Subscriber Info Response 405 with information relating to at least one of IMSI, MSISDN, name, address, email address, phone number, user provided interest profile, user statistics profile, and any other information that may be of interest.
The setup part is now basically done and the session continues with user plane traffic 406 between the UE and the PDN via the PGW and optionally via a NAT and/or FW. If NAT is used, triggered by IP packets sent from the UE, mapping update 407 may be performed; e.g. mapping private IP address with public IP address and port number.
During the IP session the PGW continually obtains statistics of the user activity through DPI and transmits 408 repeatedly 410 to the PCRF which in turn updates 409 the SUPR with relevant information.
When a UE makes a request 411 to an application server (APS), e.g. a HTTP request or similar, the APS may make a user profile request 412 to the SUPR and if the APS is allowed to connect to the SUPR, the SUPR may respond 413 with a user profile response comprising user profile information and the APS may respond 414 to the UE request in accordance with the user profile information.
If the IP session is timed out or the public/private IP address of the UE is changed a mapping update 415 may be performed. If a time out event triggers a mapping update, the mapping of the private to public IP address/port number is removed. The SUPR may optionally hold a register with historical mappings for some time in order to being able to control if a user re-attaches shortly in time. This may be useful for instance if the APS is charged for information relating to a UE; if the UE re-attaches shortly in time, the APS may not be interested in being charged again since this may be seen as a double charging of the information. If the UE is located in an environment with less optimal connection quality, the connection may be renewed quite often and thus possibly given new IP addresses often.
If the UE or core/access network actively terminates the connection, bearer termination communications 416 will be exchanged between the UE and PGW. The PGW will send a message indication IP-CAN session termination 417 to the PCRF which in turn will inform 418 the SUPR about this together with information of IMSI and IP address.
It should be noted that the word “comprising” does not exclude the presence of other elements or steps than those listed and the words “a” or “an” preceding an element do not exclude the presence of a plurality of such elements. It should further be noted that any reference signs do not limit the scope of the claims, that the invention may be at least in part implemented by means of both hardware and software, and that several “means” or “units” may be represented by the same item of hardware.
The above mentioned and described embodiments are only given as examples and should not be limiting to the present invention. Other solutions, uses, objectives, and functions within the scope of the invention as claimed in the below described patent claims should be apparent for the person skilled in the art.
ABBREVIATIONS
DPI Deep Packet Inspection
EPC Evolved Packet Core
GW GateWay
HTML HyperText Markup Language
HTTP HyperText Transfer Protocol
IP Internet Protocol
IP-CAN Internet Protocol Connectivity Access Network
MS Mobile Station
PCC Policy and Charging Control
PCEF Policy Control Enforcement Function
PCRF Policy Control Rules Function
PDN Packet Data Network
PDN-GW Packet Data Network Gateway
PGW Packet Data Network Gateway
SPR Subscription Profile Repository
SUPR Subscriber Usage Profile Repository
UE User Equipment
URI Uniform Resource Identifier, e.g. URL: Uniform Resource Locator
XML eXtensible Markup Language
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The present invention relates to a solution for handling customer activity when connecting to a wireless communication network and in particular for statistics of customer activity using the network. This is provided in a number of aspects such as methods, node, and system for reporting user profile statistics from deep packet inspection of data packets in a packet data network ( 100 ) to a policy and charging rules function entity ( 104 ) which in turn informs a subscriber usage profile repository ( 106 ), i.e. SUPR. The SUPR provides access to external application servers ( 108 ) to the subscriber usage profile information after access control.
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FIELD OF THE INVENTION
This invention relates to eyewear.
Eyewear, as used herein, is considered a generic description of a product which is worn on a user's head over a user's eyes. Eyewear, for purposes herein, includes eyeglasses, goggles, helmets with eye openings, and the like. Eyewear may be primarily for protection purposes, e.g., goggles or sunglasses, and/or eyewear may be primarily for enhancement of visual recognition, e.g., reading glasses. And eyewear may or may not include eye lenses.
BACKGROUND OF THE INVENTION
It is known to the prior art to provide eyeglasses with a rearview mirror. In this regard, it is known to the prior art to provide heavy duty or protective eyeglass frames with a rearview mirror. Such a safety oriented eyewear product is known for use in the sport of competitive cycling, or may be used simply in recreational cycling. The rearview mirror, when in the use position, allows the cyclist to look to the rear while still keeping his head oriented forward, i.e., without turning his head, so as to determine, e.g., whether it is safe to turn left or right
SUMMARY OF THE INVENTION
It has been the primary objective of this invention to provide eyewear with a rearview mirror where the rearview mirror is movable between a use position spaced from the eyewear and a storage position juxtaposed to a temple piece of the eyewear, a seat being provided in the temple piece so that the mirror can be received in that seat when in a storage position. This objective provides a desirable advantage in that it tends to remove the rearview mirror from prospective inadvertent contact with a user's hand or clothing when in the storage position because the mirror is effectively integrated into the eyewear structure in that storage position.
BRIEF DESCRIPTION OF THE DRAWINGS
Other objectives and advantages of this invention will be more apparent from the following detailed description taken in conjunction with the drawings in which:
FIG. 1 is a rear perspective view of eyeglasses in accord with the principles of this invention, a rearview mirror being shown in the storage position;
FIG. 2 is a rear perspective view similar to FIG. 1 but with the rearview mirror being shown in a use position;
FIG. 3 is a side view of the eyeglasses with the rear view mirror shown in the use position illustrated in FIG. 2;
FIG. 4 is an exploded side view illustrating assembly of the rearview mirror with a temple piece of the eyeglasses; and
FIG. 5 is a view similar to FIG. 4 illustrating a swing arm for the rearview mirror in assembly with the temple piece.
DETAILED DESCRIPTION OF THE INVENTION
Eyewear in accord with the principles of this invention is illustrated in FIGS. 1 and 2. This eyewear is in the form of eyeglasses 10 having a frame that includes lens frame 11 and two opposed side or temple pieces 12, 13. The lens frame 11 may carry tinted or non-tinted lenses 14, i.e., the eyeglasses may be sunglasses or not. And the lenses 14, of course, may be prescription lenses or not. Each temple piece 12, 13 is pivotally connected to the frame 11 by a hinge 15. Each temple piece 12, 13 is of a significant length so that it extends back over a user's ear in known fashion to retain the eyeglasses 10 in place on a user's head.
The rearview mirror structure, which is the subject of this invention, includes rearview mirror 16 connected with the left temple piece 12 as shown in the figures. The rearview mirror 16 includes a mirror 17 in a frame 18, the frame being of a generally rectangular configuration. This frame 18, as shown in FIGS. 1 and 2, cooperates with a seat 19 defined in the outboard surface 20 of the temple piece 12. The seat 19 is of a rectangular configuration analogous to that of the mirror frame 17, and is dimensioned so as to receive the rearview mirror 16 in stored relation therewith as shown in FIG. 1.
Note the thickness T of the mirror frame 18 is substantially equal to the depth D of the seat 19 defined in the outboard surface 20 of the temple piece 12. Accordingly, the surface of the mirror's rear wall 21 lies substantially flush with the outboard side wall surface 20 of the temple piece 12 when the mirror 16 is in storage position shown in FIG. 1. Note also, as shown in FIG. 3, that the seat's periphery 22 is fully within the confines of the temple piece. In other words, the configuration and size of the seat 19 is such that the mirror 16 is received wholly within the confines of the temple piece's periphery 22. Thus, inadvertent contact by a user's hand, or by a user's clothing, with the mirror 16 is less likely to occur than if the mirror was not so confined when the mirror is in the storage position. This, in turn, reduces the chance for potential stress on those joints (discussed in detail below) by which the mirror 16 is connected with the temple piece 12 when the mirror is in storage position such as might otherwise occur in the event of inadvertent contact with that temple piece or with the mirror.
A swing arm 25 is pivotally mounted by a first pivot joint 26 at one end to the mirror 16, see FIG. 4. The swing arm 25 is also pivotally mounted by a second pivot joint 27 at its other end to the temple piece 12, see FIGS. 4 and 5. The pivot joint 26 of the mirror 16 with the swing arm 25 is established by pin 28 rotatably secured in arm 25. The pin 28 is, in turn, secured to the mirror frame 18 by frictional engagement of a boss 32. The pin has a flatted head 29 received in recess 30 in the swing arm's top surface 31 at that one end, see FIG. 4. The boss 32 on the top edge 33 of the mirror frame 18 acts as a bearing surface between the mirror 16 and the swing arm 25. The pin 28 defines a pivot axis 34 oriented at right angles relative to the swing arm's longitudinal axis 35. Thus, the rearview mirror 16 is pivotable on that pivot axis 34 at the outer end of the swing arm 25.
The swing arm 25 is connected to the temple piece 12 by the ball joint 27 shown in FIGS. 4 and 5. The ball joint 27 includes a ball 37 formed integral with post 38 which in turn is formed integral with the temple piece 12. The ball 37 and post 38 are located in a recess 39 formed in the temple piece's top edge 40. A flexible inverted cup 41 is received over the ball 37, the cup being provided with slots 42 that extend from its edge 43 toward its base 44 at selected locations around its periphery so as to permit the cup's sides 45 to flex over the ball 37 as it is installed thereon. With the cup 41 installed on the ball 37, a boss 47 at the other end of the swing arm 25 is received on the cup in friction fit relation, compare FIGS. 4 and 5. The ball joint 27 at this other end of the swing arm 25 allows the swing arm to pivot between the storage and use positions, compare FIGS. 1 and 2, on a generally vertical `y` axis 48 relative to ground as shown by motion arrows 49 when the glasses are being worn. However, that ball joint 27 also allows the swing arm 25 to pivot up and down on a `z` axis 50 as shown by motion arrows 51 in FIGS. 2 and 3, and to pivot side to side on an `x` axis 52 as shown by motion arrows 53, which axes 50, 52 are generally parallel to ground when the eyeglasses are being worn. This up three dimensional pivot motion 49, 51, 53 allowed by the ball joint 27 to the rear view mirror 16 allows the user to adjust the mirror in that position which provides maximum benefit relative to the purpose for which the mirror is intended when it is in the use position shown in FIG. 2.
The interconnection of the swing arm 25 with the temple piece 12 is also structured so that the swing arm 25, when in the retracted or storage position, overlies the top edge 40 of that temple piece, see FIG. 1. Thus, the swing arm 25 is less likely to be contacted by a user or a user's clothing when in the storage position which, in turn, minimizes potential stress on the ball joint 27 when the rearview mirror 16 is stored. This for the reason, of course, that the swing arm 25 is supported from underneath by the top edge 40 of the temple piece 12. And this also because the outboard edge 55 of the swing arm 25 when in the storage position is generally flush with the outboard surface 20 of the temple piece 12. Note also, as shown in FIG. 1, that the top surface 37 of the swing arm is co-extensive with the top edge 58 of the temple piece 12 when in the storage position. Thus, the temple piece's top edge 58 in effect defines a notch or seat 59 on which and in which the swing arm 25 is received when it is in storage position.
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A rearview mirror is connected to a frame for the eyewear, the rearview mirror being movable between a use position spaced from the frame and a storage position juxtaposed to the frame. A seat is defined in the frame so that the mirror is receivable in that seat when in the storage position, thereby tending to minimize breakage of the device upon inadvertent contact with a user's hand or clothing when the mirror is stored.
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TECHNICAL FIELD OF THE INVENTION
[0001] The present invention relates generally to application of nanofibers with oil/water repellent for textiles to improve the hydrophobicity and liquid repellency properties of fabric substrate materials to which these are applied. More specifically, the invention relates to improved hydrophobicity and water protection of a fibrous fabric substrate (cotton, synthetics and/or their blends) by depositing a thin nanofiber layer and coating with a dispersion of fluoropolymers (fluorinated acrylic copolymers) that are alternative perfluorinated chemicals (PFCs) based on short-chain chemistry of varying chain length (C4, C6, C8, C10, C12, C14, etc.) perfluoroalkyl constituents.
BACKGROUND TO THE INVENTION
[0002] Fibers form, in part or in whole, a large variety of both consumer and industrial materials such as, for example, clothing and other textile materials, medical prostheses, construction materials and reinforcement materials, and barrier, filtration and absorbent materials. There are two main structural classes of fiber materials: woven and non-woven. An advantage of non-woven fiber materials is their lower production cost.
[0003] Nanofibers (fibers having diameters less than 1000 nm) are increasingly being investigated for use in various applications. Nanofibers may attain a high surface area comparable with the finest nanoparticle powders, yet are fairly flexible, and retain one macroscopic dimension which makes them easy to handle, orient and organize. Direct application of nanofiber webs or thin nanofiber layers onto garment systems can be utilized in protective textiles as breathable barriers to liquid penetration. For example, the U.S. Army Natick Soldier Center has investigated enhancement of barrier materials using a fine nanofiber layer to prevent penetration of chemical warfare agents in aerosol form. The study (Schreuder-Gibson et al., 2002) found that nanofibers of certain polymers (e.g. nylon 6,6, polybenzimidazole, polyacrylonitrile and polyurethane) provided good aerosol particle protection, without a significant change in moisture vapor transport of the system. Further, it has been found that polypropylene webs and laminates significantly enhanced barrier performance for challenge liquids having varying surface tensions. Though ultrathin nanofiber webs have exciting and unique properties, they have limited mechanical properties. The nanofiber webs are used in a composite structure with some other substrate material as a support to provide strength and durability. For use in protective clothing, nanofiber webs can be used as a component in layered fabric systems such that the protection and comfort is accessed in layered structures.
[0004] Wettability is an important property of fibrous materials for many applications. Both surface energy and surface roughness are the dominant factors for wettability or hydrophobicity of materials. The degree of wettability of a solid surface can be evaluated by contact angle (CA), a numerical value given by Young's equation. Young's Equation defines the balances of forces caused by a wet drop on a dry surface and relates the CA to three interfacial surface energies (or surface tensions) between the solid and the liquid, the liquid and the vapor, and the solid and the vapor. A water droplet is typically used as the probing liquid although some organic and ionic liquids have also been deployed. The CA can be measured from the plane of the surface. Inspired by the hydrophobic behavior of plant surfaces and animal skins, during the past decade, much research has been placed to fabricate artificial surfaces and coatings with high CAs that mimic those naturally delicate choices via millions of years' evolutions. Hydrophobicity refers to the physical property of a surface on which hydrophobic molecules repel water molecules causing higher water CAs, 74 , over 90°. A hydrophobic surface does not allow the spread of water on it. The water stands up in the form of droplets.
[0005] Nanofibers can be used to impart surface roughness of a material thereby increasing the hydrophobicity of that material. Surface roughness may be enhanced by a repellant coating and additives such as grapheme and TiO 2 . When the true CA is greater than 90°, then the angle can be increased by surface roughness.
[0006] Surface protection and fluorosurfactant products are used for many applications including carpet care, fire-fighting foam, leather, coatings, paper packaging, stone, tile and concrete coatings, and textiles. For textile applications, long-chain perfluorinated substances including perfluorinated surfactants or fluorosurfactants (perfluorinated alkylsulfonates such as Perfluorooctanesulfonic acid (PFOS) and perfluorinated carboxylates such as Perfluorooctanoic acid (PFOA)) have been widely used as water and oil repellents in fabrics and leather for stain protection applications. These compounds have unique properties to make materials stain, oil and water resistant. They can provide water and oil repellent effects on base fabric material as well as protection against chemicals, such as acids, without impairing the original softness and breathability of the fabric.
[0007] PFOS is classified as a persistent, bio-accumulative and toxic (PBT) and there are restriction on its marketing and use in different regions of the world. PFOA is bio-persistent, but is neither bio-accumulative nor toxic. In early 2006, the U.S. Environmental Protection Agency (EPA) launched the EPA 2010/2015 PFOA Stewardship Program to reduce human and environmental exposure of these compounds. The goal is to eliminate PFOA, PFOA precursors and related higher homologue chemicals from emissions and products no later than 2015. Alternative fluorotechnology or perfluorinated chemicals (PFCs) based on short chain molecules which cannot break down into PFOA have been developed and are entering the marketplace as a means to eliminate usage of PFOA, PFOA precursors and related higher homologue chemicals. These alternative PFC products are based on perfluorinated side chains with varying perfluoroalkyl constituent chain length (C4, C6, C8, C10, C12, C14, etc.) with emphasis on C8 and C6. For example, in one alternative PFC, the perfluoroalkyl constituent chains of C8 or C6 are bonded to a carboxylic acid group which is bonded to a carbon group on a main chain containing carbon and hydrogen.
[0008] The alternative PFC products, based on short-chain chemistry, provide a step-change reduction in trace impurities of PFOA below the limit of detection without compromising fluorine efficiency, offering similar or even better performance than their predecessors. Potential application of these materials include use as a stain-release finish for cotton, man-made fibers (synthetics) and blends facilitating easier removal of water- and oil-based stains during the laundering process; as an oil-, water- and stain-repellent finish for man-made fibers and blends enables spills to be blotted up quickly with a clean, dry, absorbent cloth. Treated fabrics are breathable and comfortable to wear, and the finishes remain durable after laundering. The products offer a considerable improvement in sustainability since the short-chain perfluorinated molecules that cannot break down to PFOA in the environment.
[0009] Accordingly, an ongoing need remains for improved techniques for application as an oil-, water- and stain-repellant finish using alternative PFCs.
SUMMARY OF THE INVENTION
[0010] The present invention comprises a fabric substrate coated with polymeric nanofibers and alternative PFCs for improved hydrophobicity and water repellency of the base substrate. The fabric substrate will have improved hydrophobicity and water repellency when coated with nanofibers and alternative PFCs in comparison to the same fabric substrate coated only with alternative PFCs. The polymeric nanofibers and alternative PFCs can be applied by one of the following methods:
A) According to one implementation, polymeric nanofibers are first wet laid onto a fabric substrate of cotton, synthetic or blend fibers and allowed to dry or oven baked or heat pressed to dry. Then the nanofiber-coated substrate material is dipped into a dilute solution containing alternative PFCs (based on perfluorinated side chains with varying perfluoroalkyl constituent chain lengths) and then heat pressed or oven baked to dry the composite substrate. B) According to another implementation, nanofibers are dip impregnated onto a fabric substrate of cotton, synthetic or blend fibers and allowed to dry or oven baked or heat pressed to dry. Then the nanofiber-coated substrate material is dipped into a dilute solution containing alternative PFCs and then heat pressed or oven baked to dry. C) According to another implementation, nanofibers are sprayed and aerosolized onto a fabric substrate of cotton, synthetic or blend fibers and allowed to dry. Then the nanofiber-coated substrate material is dipped into a dilute solution containing alternative PFCs and then heat pressed or oven baked to dry. D) According to another implementation, nanofibers and alternative PFCs in the same solution together are either wet-layed, dip impregnated or sprayed onto a fabric substrate of cotton, synthetic or blend fibers and allowed to dry. Then the composite material is heat pressed or oven baked.
[0015] A wide variety of polymers may be utilized as starting materials, examples of which are given below. A wide variety of alternative PFCs may be utilized as starting materials, examples of which are given below. A wide variety of fabric substrates of natural, synthetic or blend fibers may be utilized as starting materials, examples of which are given below.
[0016] Other devices, apparatus, systems, methods, features and advantages of the invention will be or will become apparent to one with skill in the art upon examination of the following figures and detailed description. It is intended that all such additional systems, methods, features and advantages be included within this description, be within the scope of the invention, and be protected by the accompanying claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] The invention can be better understood by referring to the following figures. The components in the figures are not necessarily to scale, emphasis instead being placed upon illustrating the principles of the invention. In the figures, like reference numerals designate corresponding parts throughout the different views.
[0018] FIG. 1 is a schematic representation of nanofibers coated on a substrate of synthetic fibers with added alternative PFCs (based on perfluorinated side chains with varying perfluoroalkyl constituent chain lengths).
[0019] FIG. 2 is a Scanning electron microscopy (SEM) image of nanofibers deposited on a substrate coated with alternative PFCs at (A) 1 gram per square meter (GSM) basis weight and (B) 2 GSM. The substrate top side that was coated with nanofibers is comprised of polyester fibers and the substrate back side is comprised of cellulose fibers.
[0020] FIG. 3 is the contact angle of a water droplet deposited on a substrate (A) coated with alternative PFCs, and on one (B) coated with nanofibers and alternative PFCs.
DETAILED DESCRIPTION
[0021] As used herein, the term nanofiber refers generally to an elongated fiber structure having an average diameter ranging from less than 50 nm-2 μm. The “average” diameter may take into account not only that the diameters of individual nanofibers making up a plurality of nanofibers formed by implementing the presently disclosed method may vary somewhat, but also that the diameter of an individual nanofiber may not be perfectly uniform over its length in some implementations of the method. In some examples, the average length of the nanofibers may range from 10 micros or greater. In other examples, the average length may range from 110 microns to over 25 centimeters. In some examples, the aspect ratio (length/diameter) of the nanofibers may range from 10:1 or greater. In some specific examples, nanofibers of the current invention may have aspect ratios of at least 10,000:1. Insofar as the diameter of the nanofiber may be on the order of two microns or less, for convenience the term “nanofiber” as used herein encompasses both nano-scale fibers and extremely small micro-scale fibers (microfibers).
[0022] As used herein, the term fibril refers generally to a fine, filamentous non-uniform structure in animals or plants having an average diameter ranging from about 1 nm-1,000 nm in some examples, in other examples ranging from about 1 nm-500 nm, and in other examples ranging from about 25 nm-250 nm. According to certain methods described below, fibrils are formed by phase separation from nanofibers. In these methods, a fibril may be composed of an inorganic precursor or an inorganic compound. In the present disclosure, the term “fibrils” distinguishes these structures from the polymer nanofibers utilized to form the inorganic fibrils. The length of the fibrils may be about the same as the polymer nanofibers or may be shorter.
[0023] Polymers encompassed by the present disclosure generally may be any naturally-occurring or synthetic polymers capable of being fabricated into nanofibers. Examples of polymers include many high molecular weight (MW) solution-processable polymers such as polyethylene (more generally, various polyolefins), polystyrene, cellulose, cellulose acetate, poly(L-lactic acid) (PLA), polyacrylonitrile (PAN), polyvinylidene difluoride (PVDF), conjugated organic semiconducting and conducting polymers, biopolymers such as polynucleotides (DNA) and polypeptides, etc.
[0024] Other examples of suitable polymers to form nanofibers include vinyl polymers such as, but not limited to, cellulose acetate propionate, cellulose acetate butyrate, polyethylene, polypropylene, poly(vinyl chloride), polystyrene, polytetrafluoroethylene, poly(α-methylstyrene), poly(acrylic acid), poly(isobutylene), poly(acrylonitrile), poly(methacrylic acid), poly(methyl methacrylate), poly(1-pentene), poly(1,3-butadiene), poly(vinyl acetate), poly(2-vinyl pyridine), 1,4-polyisoprene, and 3,4-polychloroprene. Additional examples include nonvinyl polymers such as, but not limited to, poly(ethylene oxide), polyformaldehyde, polyacetaldehyde, poly(3-propionate), poly(10-decanoate), poly(ethylene terephthalate), polycaprolactam, poly(11-undecanoamide), poly(hexamethylene sebacamide), poly(m-phenylene terephthalate), poly(tetramethylene-m-benzenesulfonamide). Additional polymers include those falling within one of the following polymer classes: polyolefin, polyether (including all epoxy resins, polyacetal, polyetheretherketone, polyetherimide, and poly(phenylene oxide)), polyamide (including polyureas), polyamideimide, polyarylate, polybenzimidazole, polyester (including polycarbonates), polyurethane, polyimide, polyhydrazide, phenolic resins, polysilane, polysiloxane, polycarbodiimide, polyimine, azo polymers, polysulfide, and polysulfone.
[0025] As noted above, the polymer used to form nanofibers can be synthetic or naturally-occurring. Examples of natural polymers include, but are not limited to, polysaccharides and derivatives thereof such as cellulosic polymers (e.g., cellulose and derivatives thereof as well as cellulose production byproducts such as lignin) and starch polymers (as well as other branched or non-linear polymers, either naturally occurring or synthetic). Exemplary derivatives of starch and cellulose include various esters, ethers, and graft copolymers. The polymer may be crosslinkable in the presence of a multifunctional crosslinking agent or crosslinkable upon exposure to actinic radiation or other type of radiation. The polymer may be homopolymers of any of the foregoing polymers, random copolymers, block copolymers, alternating copolymers, random tripolymers, block tripolymers, alternating tripolymers, derivatives thereof (e.g., graft copolymers, esters, or ethers thereof), and the like.
[0026] By fabric substrate is meant natural or synthetic fabrics composed of fibers of cotton, cellulose, acetate, rayon, silk, wool, hemp, polyester, spandex (including LYCRA), polypropylene, polyolefins, polyamide, nylon, aramids (e.g. Kevlar®, Twaron®, Nomex, etc.), acrylic, or poly (trimethylene terephthalate). By “fabric blends” is meant fabrics of two or more types of fibers. Typically these blends are a combination of a natural fiber and a synthetic fiber, but can also include a blend of two natural fibers or two synthetic fibers.
[0027] Superior oil- and water-repellency properties can be imparted to fabrics and fabric blends by the addition of certain fluorochemical copolymers (e.g. OLEOPHOBOL® CP-C High Conc fabric protector product from Huntsman). These can be applied to the fabric substrates in the form of an emulsion or dispersion in water or other solvent before, after or during application of other fabric treating chemicals.
[0028] Nanofibers impart surface roughness to a substrate material and can increase the hydrophobicity. When the true CA is greater than 90°, then the angle can be increased by surface roughness according to the Wenzel equation which relates the contact angle to the change in contact angle (termed Wenzel contact angle) by the ratio of actual area to projected area that occurs when a liquid is in intimate contact with a microstructured surface.
[0029] Nanofibers can be applied to the substrate fiber or synthetic blend using a variety of methods including but not limited to two-sided spraying, dip-impregnation, and wet-laying of nanofibers followed by coating with the alternative PFC materials. Nanofibers enhance the hydrophobicity and liquid repellency of the base substrate when combined with the alternative PFCs coating. The nanofibers impart additional surface roughness to the material which combines in a synergistic manner with the alternative PFCs to improve liquid repellency ( FIG. 1 ). Nanofibers of different length and different diameter can also be mixed into a dilute alternative PFC Oleophobol solution (concentration of 10 g/l or 0.1% on the weight of the bath). The receiving fabric substrate of synthetic or blend fibers is stretched on a 10″-12″ metal frame. The mixture of nanofibers and alternative PFC solution is added to the substrate by two-sided spraying or dip-impregnation. For dip impregnation, the fabric substrate is quickly dipped into pans of mixture solution. All samples are allowed to air dry. Samples are then inserted into an oven at 380 degrees (±5 degrees) for approximately 15 seconds.
EXAMPLE
[0030] Wet laying process: Cellulose acetate (Eastman CA-398-10) nanofibers (average diameter of 400 nm and lengths of ˜200-700 μm or 2-10 mm as seen in the Table below) were first wet-layed (1 to 2 GSM basis weight) onto a fabric substrate of polyester fibers. The back side of the fabric substrate was cellulose material. A dilute solution containing glycerol and water with suspended Cellulose acetate nanofibers (˜0.1% solids) was poured onto the polyester fabric substrate placed on top of a filter fabric (80 mesh size). A wet-dry shop vacuum (Shop-Vac 6-Gallon 3 Peak HP) was used to pull vacuum to drain the liquid through the filter fabric and lay the nanofibers down on top of the polyester fabric substrate. The sample was then washed and then heat pressed or oven baked. The SEM images in FIG. 2 shows the nanofibers deposited on the fabric substrate of polyester at a basis weight of (A) 1 and (B) 2 GSM. Finally, the nanofiber-coated polyester fabric substrate was dipped into a aqueous bath containing Oleophobol 7858 (Oleophobol CP-C) at a concentration of 10 g/l or 0.1% on the weight of the bath. The dispersion of fluoropolymers was allowed to dry and then either heat pressed for one minute at 171° C. or oven baked for one minute at 193° C. (380° F.). The polyester fabric substrate sample was thus coated with cellulose acetate nanofibers and with oleophobol alternative perfluorinated compounds (PFCs).
[0031] Contact angle measurement: Water droplet side profiles were measured with a drop shape analyzer consisting of a level stage, white light source and 5.0 megapixel Sony DSC-V1 digital camera attached to a microscope head. The microscope head and camera lens allowed for a maximum total visual magnification up to 60×. The coated and uncoated fabric substrates studied had high contrast with the dark background. Side view photographs were taken. ImageJ (version 1.45) software was used to measure the cross-sectional area A, drop height h, contact radius a, and contact angle θ from the digital images.
[0000]
TABLE
Contact Angle Measurement Data
NF Avg.
NF Weight
Heat
Contact
Sample Name
Dia. (nm)
NF length
Basis (GSM)
Process
Angle (°)
Control_Baked_1_114_Fit
—
—
0
Baked 1 min
114
380° F.
Control_Pressed_1_115_Fit
—
—
0
Heat Press
115
1 min 171° C.
1gsm_Chopped_Baked_1_136_Fit
400 nm
Chopped;
1
Baked 1 min
136
200-700 μm
380° F.
1gsm_Chopped_Pressed_1_137_Fit
400 nm
Chopped;
1
Heat Press
137
200-700 μm
1 min 171° C.
1gsm_Whole_Baked_1_132_Fit
400 nm
Whole; 2-10
1
Baked 1 min
132
mm
380° F.
1gsm_Whole_Pressed_1_136
400 nm
Whole; 2-10
1
Heat Press
136
mm
1 min 171° C.
2gsm_Chopped_Baked_1_134_Fit
400 nm
Chopped;
2
Baked 1 min
134
200-700 μm
380° F.
2gsm_Chopped_Pressed_1_140_Fit
400 nm
Chopped;
2
Heat Press
140
200-700 μm
1 min 171° C.
2gsm_Whole_Baked_1_135_Fit
400 nm
Whole; 2-10
2
Baked 1 min
135
mm
380° F.
2gsm_Whole_Pressed_1_136_Fit
400 nm
Whole; 2-10
2
Heat Press
136
mm
1 min 171° C.
[0032] The table above lists contact angles for the samples tested. The first two control samples of polyester fabric substrate coated with Oleophobol 7858 that were oven backed and heat pressed had contact angle measurements of 114° and 115°, respectively. Adding 1 or 2 grams per square meter (GSM) of nanofibers to the polyester fabric substrate and then coating with Oleophobol 7858 increased the hydrophobic contact angle (range of)132-140° . FIG. 3 shows two sample images at a contact angle of (A) 114° and (B) 137° for the control pressed and added nanofibers at 1 GSM pressed samples, respectively. The average contact angle of the oleophobol-coated substrate samples with 1 GSM of nanofiber was 135.3°, whereas when 2 GSM nanofibers were laid down on the polyester fabric substrate the average contact angle increased to 136.3°. The heat treatment did affect the contact angle of the nanofiber-coated substrate. However, the trend was different depending on fiber length for the 1 GSM and 2 GSM coated substrates. For the substrates that had 1 GSM of nanofibers that were not chopped short and longer in length (2-10 mm), the contact angle was different depending on the heat treatment-132° for baked and 136° for heat pressed. For the substrates that had 2 GSM of nanofibers that were chopped (2-10 mm), the contact angle was different depending on the heat treatment-134° for baked and 140° for heat pressed.
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The invention relates to improved hydrophobicity and water protection of a fibrous fabric substrate (cotton, synthetics and/or their blends) by depositing a thin nanofiber layer and coating with a dispersion of fluoropolymers (fluorinated acrylic co-polymers) that are alternative perfluorinated chemicals (PFCs) based on short-chain chemistry of varying chain length (C4, C6, C8, C10, C12, C14, etc.) perfluoroalkyl constituents.
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FIELD OF THE INVENTION
The present invention pertains to a flushing means at a lavatory installation having a toilet bowl, with a flushing water tank, which has a closure, which is to be opened to trigger a flushing.
BACKGROUND OF THE INVENTION
Flushing means of this type have been generally known. In such flushing means, the flushing water tank is a flush tank in which a certain amount of water is stored for flushing the toilet bowl. Upon opening a drain valve, this water flows through a flushing elbow and into the toilet ring of the toilet bowl and through the water outlet openings of this toilet ring into the toilet bowl. Such flush tanks are substantially less noisy than so-called pressurized flushing valves, in which the flushing water flows into the toilet bowl directly from a pressure pipe. However, flush tanks have the drawback that they are relatively bulky and correspondingly require much space.
SUMMARY AND OBJECT OF THE INVENTION
The basic object of the present invention is to provide a flushing means of the above-mentioned type, which have even less noise with an at least equal flushing effect and also requires less space.
This object is accomplished in a flushing means of this class by the closure being arranged at the water outlet openings of the toilet bowl. In the flushing means according to the present invention, the closure is not located, as is usual, in the bottom of a flush tank, but at the water outlet openings of the toilet bowl. When viewed in the direction of flushing, the closure is consequently moved farther down into the toilet bowl in the flushing means according to the present invention. The toilet ring thus also forms an area of the water tank and correspondingly accommodates part of the necessary flushing water. The tank for the flushing water can be made smaller corresponding to this amount and it can therefore be made more compact. Since the toilet ring is filled with flushing water already before a flushing is triggered, the hitherto unavoidable air noises during the flow of the flushing water into the toilet ring are avoided. The flushing means according to the present invention therefore makes it possible to substantially reduce the noise generation during flushing even more.
A flushing elbow is not necessary in the flushing means according to the present invention. As a result, the hitherto unavoidable loss of energy in the flushing elbow is avoided. The same flushing effect can thus be achieved in the flushing means according to the present invention at a lower water pressure level.
An especially compact and space-saving flushing means is obtained according to a variant of the present invention if the flushing water tank forms one unit with the toilet ring. If the toilet ring is designed as a toilet seat according to a variant of the present invention, inexpensive manufacture and at the same time also simple mounting are achieved. Thus, the toilet ring now forms part of the water tank and can be mounted with same on the toilet bowl. However, a design in which the toilet ring is part of the toilet bowl is also possible. This ring may consist of ceramic or even an attached ring made of plastic.
An especially advantageous closure is obtained for the water outlet openings if the closure has a membrane, which is in contact with the outlet openings of the flushing water tank and can be lifted off from these openings to trigger the flushing. This membrane is preferably designed as a flexible tube and extends into the toilet ring of the toilet bowl. An especially simple actuation of the closure is guaranteed if the membrane can be connected to a water pipe and can be filled with tap water and can be expanded for the closure of the outlet openings. The pressure in this flexible tube-like membrane is then reduced on triggering a flushing. This is preferably performed with a valve, by which the membrane is connected to the water pipe in one position and to the ambient air in another position.
According to a variant of the present invention, the flushing water tank is formed by an annular area and a box-like area, wherein part of the flushing water is stored in the annular area and one part of the flushing water is stored in the box-like area, and the two areas are connected to one another. The annular area forms the toilet ring and the box-like area is preferably arranged at the rear end of this ring. Since an essential part of the flushing water is located in the annular area, the box-like area is made substantially smaller than a usual flush tank. This annular area may be made of a plastic and may form the top edge of the toilet bowl. Since the toilet ring of the toilet bowl does not need to be made of ceramic in this case, such a toilet bowl can be manufactured substantially more simply and at a lower cost. The toilet edge and the toilet bowl as well as the toilet seat may thus be formed by the annular area of the flushing water tank.
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 shows a partial sectional view of a flushing means according to the present invention at a lavatory installation,
FIG. 2 shows a three-dimensional view of the flushing means,
FIG. 3 shows another view of the flushing means,
FIG. 4 shows another view of the flushing means, wherein part of the flushing water tank is cut away,
FIGS. 5 and 6 show sections of the flushing means to explain the mode of operation of the closure,
FIGS. 7 and 8 schematically show a sectional view of a flushing valve,
FIG. 9 schematically shows a section through a variant of the flushing means, and
FIG. 10 shows another section through part of the flushing means according to FIG. 9.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows a lavatory installation 1 with a flushing means 2 and a ceramic part 3, which has in the usual manner a foot 8, a siphon 6 with siphon water 9 as well as a soil pipe connection 7. The ceramic part 3 has a bowl-like wall 5 with an inside 5a, which can be flushed with the flushing means 2, wherein the flushing water flows downward to the siphon 6 along the inside 5a in the direction of the parts 42. The siphon 6 is emptied and subsequently filled here in the known manner.
The flushing means 2 is placed on a top edge 43 of the ceramic part 3 and forms, according to FIGS. 2 through 4, a unit comprising essentially a tank 10 and an annular seat 22. The tank 10 and the seat 22 are connected to one another by a short channel 21. As is shown especially in FIG. 3, a plurality of flushing openings 26 are arranged at spaced locations from one another on the underside of the seat 22. As can be seen, these openings 26 are distributed over the entire underside 24 of the seat 22. The flushing openings 26 may be round, especially circular openings or even slots.
According to FIGS. 5 and 6, the flushing openings 26 are connected to a channel 25, which extends inside the seat 22 in the circumferential direction and is connected to an interior space 44 of the tank 10 via the channel 21. These openings 26 can be closed with a flexible tube-like membrane 19 of a closing member 18. The openings 26 thus form a closure with the closing member 18, and the said closure closes the interior space of the channel 25 to the outside. The membrane 19 forms a ring 19b, which leads at a rear end of the seat 22 via a flexible tube section 19a to a flush valve 17, which is arranged inside the tank 10 according to FIG. 4. The membrane 19 occupies only a comparatively small part of the channel 25. This channel 25 accommodates a substantial part of the flushing water 45, as is indicated in FIG. 5. The other part of the flushing water 45 is located in the interior space 44 of the tank 10. The two amounts of water are in connection with one another via the channel 21.
The flush valve 17 is connected via a pipe 16 to a pipe 14, which is connected via the valve 15 to an end 11 projecting from the housing 20 of the tank 10. According to FIG. 1, this end 11 is connected in the usual manner to a corner valve 4 of a supply pipe 46. To actuate the flush valve 17, e.g., a button 31 is arranged thereon, which is accessible from the outside of the tank 10 according to FIG. 2 and is pressed downward to trigger a flushing. However, other mechanical or even electric triggering, e.g., remote triggering, is also possible.
According to FIGS. 7 and 8, the flush valve 17 has a housing 29, in which a valve body 30 is mounted. The button 31 is arranged at the top end of the valve body 30, and a resetting spring 34 is arranged at the lower end. The resetting of the valve body 30 is performed in the known manner by self-closure, e.g., according to CII-A 588658 and U.S. Pat. No. 2,629,401. In the position shown in FIG. 7, a passage 33 connects the pipe 16 to the closing member 18. The membrane 19 is thus connected to the pipe 16 in this position of the flush valve 17 and is filled with pressurized water from the supply pipe 46. Thus, a water pressure that holds the membrane in an expanded position indicated in FIG. 5 is present inside the membrane 19. Thus, the annular area of the membrane 19 has, e.g., an approximately circular cross section, as is indicated by solid lines in FIG. 5. The membrane 19 is supported on the top side at a plurality of projections 47 arranged in the channel 25 and seals the flushing openings 26 at valve seats 27 arranged on the inside due to its inner pressure. The valve body 30 is held by the spring 34 in the position shown in FIG. 7. The intake valve is likewise connected to the supply pipe 46 via the pipe 14.
To trigger flushing, the valve body 30 is moved downward by means of the button 31 against the force of the spring 34 into the position shown in FIG. 8. In this position, the membrane 19 is connected to an outwardly open pipe branch 48 of the housing 29 via a connection channel 32. The inner pressure in the membrane 19 is lowered as a result, because the membrane 19 is no longer connected to the pipe 16. Due to the elasticity of the membrane 19, the annular area 19b regains a shape in which the cross section is substantially reduced and in which the flushing openings 26 are no longer sealed against the channel 25, as is shown in FIG. 6. The relaxed position of the membrane 19 is shown by solid lines in FIG. 6. The broken lines indicate the tensioned and sealing membrane 19 here. Since the flushing openings 26 are now free, the flushing water 45 flows downward at these openings 26 in the direction of the arrows 49 and into the bowl 5 of the ceramic 3. The flushing process is terminated when the flushing water 45 has flown completely into the bowl 5 and the channel 25 as well as the interior space 44 of the tank 10 have been emptied. The amount of his rushing water is, e.g., 6 L or less. After flushing, a float 13 of the intake valve 12 initiates the refilling of the flushing means 2 with flushing water. At the same time, the valve body 30 returns into the position shown in FIG. 7, the membrane 19 is inflated again due to the said membrane 19 being connected to the pipe 16 and it closes the flushing openings 26. As soon as the channel 25 and the tank 10 have been refilled with flushing water, the float 13 closes the intake valve 12. The flushing means 2 is thus again ready for another flushing.
The flushing means 2 is manufactured separately from the ceramic 3 as a unit essentially from plastic. The seat surface 22 is placed on the top edge 43 of the ceramic 3 and is fastened by means of fastening means, not shown here. A cover, not shown here, which covers the opening of the seat 22, may be arranged on the flushing means 2 at the same time. This cover lies on the top side of the seat 22. The seat 22 thus replaces the usual toilet ring, which form [sic - Tr.Ed.] the upper edge of the ceramic 3 in the prior-art lavatory installations.
FIGS. 9 and 10 show an embodiment in which the closing member 18 extends in a channel 36 of the toilet bowl 35. The channel 36 forms an area made integrally in one piece here and thus the upper edge of the ceramic bowl 35. A plurality of flushing openings 37, which correspond to the openings 26, are correspondingly arranged in this edge on the underside. The closing member 18 extends over the entire area of the channel 36 and operates as above to close the openings 37 and to release them for flushing. As is shown in FIG. 10, the closing member 18 is introduced into the tank 10 at a pipe branch 40 of the tank 10. To connect the pipe branch 40 to the channel 36, the bowl 35 has an opening 39 at a rear end, through which opening the pipe branch 40 is introduced. The pipe branch 40 is tightly connected to the channel 36 with means not shown here.
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.
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The flushing device has a flushing water tank with a closure, which is to be opened to trigger a flushing. The closure is arranged at water outlet openings of the toilet bowl. The toilet ring of the toilet bowl can thus accommodate part of the flushing water needed for the flushing. The flush tank proper can thus be made substantially smaller and flushing will be less noisy, because air noises are avoided during the flow of flushing water into the toilet ring.
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TECHNICAL FIELD
This invention relates to a method and apparatus for measuring the transfer efficiency of a coating material. This method and apparatus is suitable for measuring the transfer efficiency of any coating material, but is particularly suitable for measuring the transfer efficiency of a powder coating material.
BACKGROUND OF THE INVENTION
In a typical powder coating spray process, not all of the coating material that is sprayed adheres to the target substrate. The amount of powder coating material that actually ends up applied to the target substrate is a function of the transfer efficiency of the coating material. The average transfer efficiency for a coating material can be calculated by dividing the change in weight of the target substrate by the change in weight of the powder coating source dispensing the powder coating material. The transfer efficiency is conveniently expressed as a percentage of the powder coating material that adheres to the target substrate relative to the powder coating material that is sprayed.
The current practice is to measure the average transfer efficiency of a powder coating material by measuring the starting and ending weight of the target substrate and the total amount of powder sprayed. This is a time consuming, manually-intensive procedure. Moreover, this procedure does not measure the true transfer efficiency of a powder coating material due to the fact that the transfer efficiency values observed tend to vary over the course of the test cycle. In this regard, the transfer efficiency values observed with an uncoated or clean substrate at the beginning of the test are typically higher than at the end of the test when the substrate is coated. This is at least in part due to electrical insulating affects that result from accumulated powder on the target substrate. Until now it has not been possible to measure instantaneous transfer efficiency values at anytime during the test cycle, and this has prevented researchers from measuring the true transfer efficiency values of powder coating materials.
The present invention overcomes these problems by providing a method for measuring instantaneous transfer efficiency values of coating materials at any time during a test cycle. This permits measurement of the true transfer efficiency values of such coating materials. The term "true transfer efficiency value" is the transfer efficiency value of a coating material that is measured after start up of the test when the substrate is no longer "uncoated or clean" and prior to the point at the end of the test when electrical insulating affects caused by accumulated powder on the substrate lead to a deterioration or reduction in the observed transfer efficiency value.
SUMMARY OF THE INVENTION
This invention relates to a method for measuring the transfer efficiency of a coating material, the method comprising:
(A) electrostatically spraying said coating material on to a target substrate, the coating material being drawn from a coating source during said spraying; and performing steps (B), (C) and (D) during step (A);
step (B) comprising measuring the change in weight of the target substrate;
step (C) comprising measuring the change in weight of the coating source; and
step (D) comprising calculating the transfer efficiency of the coating material by dividing the change in weight of the target substrate measured in step (B) by the change in weight of the coating source measured in step (C), the number of measurements in each of steps (B) and (C) and the number of calculations of transfer efficiency in step (D) ranging from about 1 per 5 seconds to about 500 per second.
The invention also relates to an apparatus, comprising:
an electrostatic spray gun for spraying a coating material;
a target substrate positioned in spaced relationship from said spray gun for receiving coating material sprayed from said spray gun;
a load cell adapted to generate electrical signals indicative of the weight of said target substrate;
a vessel for containing said coating material, said vessel being connected to said spray gun through a tubular connector, the tubular connector being adapted to convey said coating material from said vessel to said spray gun;
another load cell adapted to generate electrical signals indicative of the weight of said vessel;
said load cell and said another load cell being linked to a computer to permit the computer to (1) receive said electrical signals indicative of the weight of said vessel and said electrical signals indicative of the weight of said target substrate, (2) calculate changes in the weight of said vessel and changes in weight of said substrate as coating material is drawn from said vessel and sprayed on to said target substrate using said spray gun, and (3) calculate the transfer efficiency of the coating material by dividing the change in weight of said target substrate by the change in weight of said vessel.
BRIEF DESCRIPTION OF THE DRAWINGS
In the annexed drawings, like parts and features are identified by like references.
FIG. 1 is a schematic illustration of a side view of one embodiment of the inventive apparatus, wherein the spray gun is stationary relative to the target substrate.
FIG. 2 is a schematic illustration of a partial top plan view of an alternative embodiment of the inventive apparatus, wherein the spray gun is movable relative to the target substrate.
FIG. 3 is a plot of instantaneous transfer efficiency values versus time for the spray process disclosed in Example 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The inventive method may be performed using the inventive apparatus illustrated in FIG. 1. Referring to FIG. 1, the apparatus, in its illustrated embodiment, is comprised of an electrostatic spray gun 10 for spraying a coating material 12; a target substrate 14 positioned in spaced relationship from the spray gun 10 for receiving coating material 12 sprayed from spray gun 10; a load cell 16 communicating with the substrate 14 and adapted to generate electrical signals indicative of the weight of substrate 14; and a vessel 18 for containing the coating material 12. The vessel 18 is connected to spray gun 10 through a tubular connector 20, the tubular connector 20 being adapted to convey coating material 12 from vessel 18 to the spray gun 10. Vessel 18 communicates with another load cell 22 which is adapted to generate electrical signals indicative of the weight of the vessel 18.
The load cells 16 and 22 are linked to a computer (not shown in the drawings) and transmit electrical signals to the computer to permit the computer to (1) receive electrical signals indicative of the weight of vessel 18 and electrical signals indicative of the weight of the substrate 14, (2) calculate changes in the weight of the vessel 18 and changes in weight of the substrate 14 as coating material 12 is drawn form vessel 18 and sprayed on to substrate 14 using said spray gun 10, and (3) calculate the transfer efficiency of the coating material 12 by dividing the change in weight of the substrate 14 by the change in weight of the vessel 18.
The spray gun 10 and the target substrate 14 are attached to and depend from cantilevered arm 24. Cantilevered arm 24 is mounted on and projects outwardly from vertical support member 26. Vertical support member 26 is mounted on and projects upwardly from base plate member 28. Base plate member 28 is supported by vibration isolators 30.
Spray gun 10 is attached to bracket 32 which is slidably mounted on cantilevered arm 24. The position of spray gun 10 relative to the position of target substrate 14 can be varied by moving spray gun 10 and bracket 32 to the left or to the right (as depicted in FIG. 1) along cantilevered arm 24. By doing this, the distance between the spray gun 10 and the target substrate 14, and as result the distance the coating material is sprayed, can be varied. In one embodiment, the distance between the spray head of spray gun 10 and target substrate 14 is from about 1 to about 60 inches, and in one embodiment about 1 to about 40 inches, and in one embodiment about 2 to about 30 inches, and in one embodiment about 4 to about 20 inches, and in one embodiment about 4 to about 18 inches, and in one embodiment about 6 to about 12 inches.
Target substrate 14 communicates with load cell 16. Load cell 16 is attached to and depends from cantilevered arm 24. Load cell 16 is a tension load cell which has an operating range suitable for the size and weight of the target substrate 14 and the anticipated weight of the coating material 12 to be sprayed on to the target substrate. In one embodiment, the load cell 16 has a 0-250 gram range with precision of ±0.01 gram. Target substrate 14 is connected to load cell 16 through non-conductive cable connector 34. Deflection cowling 36 surrounds load cell 16 and isolates it from coating material 12 that is sprayed during the test procedure and from flowing air. Backing plate 38 is positioned adjacent to target substrate 14 and prevents substrate 14 from movement to the right (as depicted in FIG. 1) during the spraying of coating material 12 onto substrate 14. Backing plate 38 can be made of a suitable low-surface energy material that does not interfere the measurements of weight change for target substrate 14. An example of such a low-surface energy material is Teflon™. Backing plate 38 is mounted on L shaped support member 40. Support member 40 is attached to and depends from cantilevered arm 24. Ground wire 42 is connected to backing plate 38 and runs to a convenient grounding location 43.
Target substrate 14 can have any desired shape or size and can be made of any conductive material. The term "conductive material" is used herein to refer to any material having a resistance equal to or less than 10 10 ohms per square centimeter. The target substrate 14 can be made of metal, wood, plastic, or a combination thereof, with metal substrates being preferred. The substrate can be a flat panel or it can have a three-dimensional shape. The substrate 14 can have the shape of any object or part (e.g., automotive door panel, molded part, etc.) that can be spray coated. In one embodiment, the target substrate is an aluminum sheet test panel having the dimensions of about 6×6 inches to about 36×36 inches, and in one embodiment about 12×12 inches.
In the embodiment depicted in FIG. 1, the spray gun 10 and the target substrate 14 are stationary relative to each other during the operation of the test procedure. However, those skilled in the art will recognize that the apparatus can be modified to permit the spray gun 10 and/or target substrate 14 to move relative to the other during operation of the test procedure. In one embodiment, the spray gun 10 is moveable relative to the target substrate 14. This is illustrated in FIG. 2. Referring to FIG. 2, the spray gun 10 is moving from right to left (as viewed from overhead) during spraying while the target substrate 14 remains in a fixed position. It will also be recognized that mounting bracket 32 can be modified to permit a pivotal movement of spray gun 10 during spraying.
Vessel 18 is mounted on load cell assembly 44 which includes load cell 22, upper support plate 46 and lower support plate 48. Load cell 22 is a compression load cell which typically has a 0-5 kilogram capacity. Vessel 18 can be any enclosed vessel suitable for holding coating material 12 during the test procedure. Vessel 18 includes a pump 48 for transporting the coating material 12 from vessel 18 to spray gun 10. In one embodiment, the coating material 12 is a powder coating material, and vessel 18 is a fluidized bed dispenser. In this embodiment, the fluidizing pressure is typically about 8 to about 15 psig, and in one embodiment about 8 to about 10 psig. The powder delivery pressure (i.e., the pressure used to advance the powder throught tubular connector 20) is typically about 5 to about 50 psig, and in one embodiment about 5 to about 30 psig, and in one embodiment about 5 to about 15 psig, and in one embodiment about 10 psig.
The electrostatic spray gun 10 can be an electrostatic corona gun or an electrostatic tribo charging gun. The spray gun typically operates with a voltage potential of up to about 100 kilovolts, and in one embodiment about 60 to about 100 kilovolts, and in one embodiment about 80 kilovolts. The spray-gun typically uses air to atomize the coating material 12 being sprayed, the atomizing pressure typically being about 5 to about 15 psig, and in one embodiment about 10 psig. The flow rate of the coating material 12 through the spray gun 10 is typically about 10 micrograms to about 5 grams per second, and in one embodiment about 0.1 to about 5 grams per second, and in one embodiment about 0.2 to about 5 grams per second, and in one embodiment about 0.5 to about 5 grams per second, and in one embodiment about 0.5 to about 3 grams per second, and in one embodiment about 1 gram per second. The duration of the spraying for a typical test procedure is about 5 to about 120 seconds, and in one embodiment about 10 to about 90 seconds, and in one embodiment about 15 to about 60 seconds and in one embodiment about 20 to about 40 seconds.
The coating material can be any sprayable material including paint, shellac, varnish, ink and the like. These include water-based paint and coating materials as well as solvent-based painting and coating materials. The coating material can be an ink coating composition, including water-based, solvent based or radiation-cured (e.g., UV-cured) ink coating compositions. The coating material can be a lubricating oil or a grease. In a particularly advantageous embodiment of the invention, the coating material is a powder coating material. The average particle size of the sprayed coating material is from about 0.1 to about 200 microns, and in one embodiment about 1 to about 100 microns, and in one embodiment about 5 to about 100 microns, and in one embodiment about 10 to about 100 microns, and in one embodiment about 15 to about 100 microns, and in one embodiment about 25 to about 75 microns.
The apparatus depicted in FIG. 1 is typically mounted within a spray booth enclosure (not shown in the drawings) to contain overspray and to comply with environmental concerns. The air flow induced by the spray booth fan typically provides an air flow velocity in the direction of the spraying in the range of up to about 200 feet per minute, and in one embodiment up to about 150 feet per minute, and in one embodiment in the range of about 60 to about 100 feet per minute.
The computer and computer software can be any combination of hardware and software capable of (1) receiving electrical signals from load cell 22 indicative of the weight of vessel 18 and electrical signals from load cell 16 indicative of the weight of target substrate 14, (2) calculating changes in the weight of vessel 18 and changes in the weight of substrate 14 as coating material 12 is drawn from vessel 18 and sprayed on to substrate 14 using spray gun 10, and (3) calculating the transfer efficiency of the coating material 12 by dividing the change in weight of substrate 14 by the change in weight of vessel 18. The number of calculations of transfer efficiency the computer hardware and software must handle are in the range of about 1 calculation per 5 seconds to about 500 calculations per second, and in one embodiment about 1 to about 100 calculations per seconds, and in one embodiment about 1 to about 50 calculations per second, and in one embodiment about 1 to about 25 calculations per second, and in one embodiment about 5 to about 15 calculations per second, and in one embodiment about 10 calculations per second. An example of the computer hardware that can be used is an IBM-80486 PC machine (66 MHZ) NT compatible software with at least 8 MB RAM capable of spreadsheet and multi-tasking functions. An example of the software that can be used is ACR Systems Inc. British Columbia, Canada Trendreader® software #TR-WIN-SRP with 12 bit resolution Excel 7.0 with appropriate visual-basic macro code used for data tabulation. The computer hardware and software are capable of providing a plot of instantaneous transfer efficiency values versus time over the duration of the spray test procedure.
The following example is provided to further illustrate the invention.
EXAMPLE 1
A powder coating material 12 is sprayed on to a target substrate 14 under following conditions using the apparatus depicted in FIG. 1:
Spray gun: Nordson Corp., Westlake, Ohio. Versa-Spray® II Model No. 173125A.
Target substrate: 12×12 inch 3000 series aluminum panel.
Powder coating material: Polyester urethane resin based powder coating material having average particle size of 35-45 microns.
Load cell 16: Sensotec Inc., Model No. AL311AN (250 gram load cell).
Load cell 22: Sensotec Inc., Model No. 41-0838-02-3 (10 pound load cell).
Vessel 18: Nordson Corp., Model No. HR-1-4.
Load Cell Amplifier: Daytronics Corp., Model No. 3270.
Spray Gun Amplifier: Nordson Corp., Model No. 173096A.
Data Logger: ACR Systems, Model No. 01-0014 Process Signal Logger.
Fluidizing pressure: 8-10 psig.
Powder delivery pressure: 10 psig.
Atomizing air pressure: 10 psig.
Spray gun voltage: 80 kilovolts.
Powder flow rate: 1 gram per second.
Spray gun to target substrate distance: 12 inches.
Spray duration: 30 seconds.
Transfer efficiency calculations: 10 per second.
Air flow rate: 150 ft/min.
Computer: IBM-80486 PC machine (66 MHZ) NT compatible software with at least 8 MB RAM capable of spreadsheet and multi-tasking functions.
Software: ACR Systems Inc. Trendreader® software #TR-WIN-SRP with 12 bit resolution Excel 7.0 with visual-basic macro code used for data tabulation.
The results are plotted in FIG. 3 which is a plot of instantaneous transfer efficiency values versus time for the tested powder coating material. The line drawn through the plot extending from 4 to 30 seconds indicates that the instantaneous transfer efficiency values measured early in the test cycle (e.g., at 10 seconds into the test) are approximately the same as those measured late in the test cycle (e.g., at 28-30 seconds into the test). This indicates that the true transfer efficiency value of the coating material can be determined with the data in this range. The true transfer efficiency value of the coating material is the transfer efficiency that is measured after the plot of instantaneous transfer efficiency values versus time stabilizes or flattens out and prior to any significant downtrend (not shown in FIG. 3) resulting from electrical insulating affects caused by accumulating coating material on the target substrate. Stabilization of the curve in FIG. 3 occurs at about 10 seconds into the test. The true transfer efficiency value for the coating material tested in this example is 65%-70%.
An advantage of this invention is that it provides a measure of the true transfer efficiency value of coating materials. The inventive method is useful as a screen test for evaluating coating formulations and additives for such formulations. This method permits the user to identify coating formulations that increase electrostatic attraction, reduce back-ionization tendencies, and produce superior film properties (gloss, adhesion, friction control, etc.).
While the invention has been explained in relation to its preferred embodiments, it is to be understood that various modifications thereof will become apparent to those skilled in the art upon reading the specification. Therefore, it is to be understood that the invention disclosed herein is intended to cover such modifications as fall within the scope of the appended claims.
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A method and apparatus for measuring the transfer efficiency during the electrostatic spraying of a coating material (e.g. powder coating) is provided. The transfer efficiency can be measured during the test cycle rather than measuring an average transfer efficiency for an electrostatic spray cycle. A cycle may include the initial time when the substrate is "uncoated or clean" and an end point of the test when electrical insulating effects caused by accumulated powder on the substrate lead to a reduction in the transfer efficiency. The method uses computer based calculation software and a computer. The computer is connected to load cells that measure weight changes of a target substrate and a vessel containing the coating material to be sprayed.
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CROSS REFERENCE TO RELATED APPLICATIONS
This is a divisional of U.S. patent application, Ser. No. 08/908,648, now U.S. Pat. No. 5,966,591 issued Oct. 12, 1999 filed on Aug. 7, 1997, and titled “Method And Tool For Handling Micro-Mechanical Structures”, which is incorporated herein by reference in its entirety.
The present patent application relates to patent application titled “Magnetic Coil Assembly”, by Peter Bischoff and Chak Man Leung, Ser. No. 08/844,003, filed on Apr. 18, 1997, and which is incorporated herein by reference.
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to the field of micro-mechanics. It particularly relates to a method and tool for handling micro-mechanical structures such as thin film micro-devices, and further to micro-mechanical structures made according to this method. This invention more specifically relates to a method for processing magnetic coil assemblies for use in data read-write heads.
2. Description of Related Art
In the field of miniaturization there is a growing interest in manufacturing micro-mechanical structures on the scale of micrometers. Many of these miniature structures are thin film devices made using semiconductor processing techniques. One of the critical steps in the manufacturing of these miniature structures involves the simultaneous handling of numerous miniature structures to enable mass-production.
U.S. Pat. No. 5,174,012 to Hamilton, which is incorporated herein by reference, describes an integrated head/flexure/conductor structure for the reading and writing information with respect to a relatively moving medium, and a method for manufacturing the same. The proposed structure takes the form of a micro-dimension, elongate, dielectric flexure body. Embedded within such body, a magnetic read/write pole structure and an electrical coil and conductor structure are operatively associated with the pole structure. The flexure body and the embedded constitutes are formed on an atom-by-atom basis utilizing one or more conventional material-deposition processes. The method of the invention is employable, as well, to create read/write structural components which may be less than a fully integrated read/write head/flexure/conductor structure.
U.S. Pat. No. 5,479,694 to Baldwin, which is incorporated herein by reference, describes a method for mounting an integrated circuit device onto a printed circuit board (PCB) by inducing a magnetic field of a selected strength at the surface of the PCB to temporarily hold the IC device onto the PCB. The IC device is provided with magnetic material which is attracted by the magnetic field. The magnetic field is maintained while the IC device and PCB are tested, and then subsequently during soldering when the IC device is permanently bonded to the PCB.
U.S. Pat. No. 5,567,332 to Mehta, which is incorporated herein by reference, describes a gaseous process for removing and vaporizing a portion of a silicon oxide film from between a substrate and a superstructure leaving a space between the substrate and the superstructure. The silicon oxide layer is removed in two steps. In the first step the bulk of the silicon oxide layer is removed by a rapid liquid or gaseous etching process, leaving a portion of the silicon oxide layer directly underlying the superstructure in place so as to support the superstructure during a wash cycle. In the second silicon oxide removal step the substrate is introduced to a high flow rate gaseous environment containing a relatively high concentration of anhydrous HF to which no, or only a relatively very low amount of, additional water vapor is provided until the silicon oxide directly underlying the superstructure has been removed.
As micro-mechanical structures are becoming smaller, lighter and more fragile, handling has become a serious problem from the standpoint of post wafer release processing. The size of these structures renders their mass production impractical when each miniature structure is handled individually. For instance, when a thin film device is selected it is broken away from the array of thin film devices using various techniques. However, the separation of the individual miniature structure may impart damage to that structure, or may cause it to be lost. In addition, cleaning, handling and testing the individual miniature device represent a very tedious and difficult task, and a potential source of contamination.
Therefore, there is still a great and unsatisfied need for a method and tool for handling and processing micro-mechanical structures such as thin film devices during the manufacture process.
SUMMARY OF THE INVENTION
One aspect of the present invention is to provide an array of micro-devices such as thin film devices that enables simultaneous mass handling and processing of these thin film devices.
Another aspect of the present invention is the inclusion of a magnetic or non-magnetic matrix that adds tensile strength to the array of micro-devices and that enables convenient handling, either manually or with a variety of tools such as a magnetic pick-up tool.
Yet another aspect of the present invention is to enable post-substrate release processing of the array of micro-devices such as rinsing, photoresist stripping, cleaning, and drying, without damaging this delicate array of micro-devices.
Still another aspect of the present invention is to enable convenient wire bonding, conformal coating, testing, and separation of the individual micro-devices from the array.
According to the present invention, a plurality of micro-devices and links are simultaneously formed on a wafer, with the links interconnecting the micro-devices for maintaining a unitary array structure. A matrix of magnetic strips is then formed to impart added overall tensile strength to the array. The magnetic strips are secured to the links and form a planar support grid therewith. The array of micro-devices is then released from the wafer and lifted therefrom by means of a magnetic pick-up tool. Using the pick-up tool, the array is transferred onto a magnetic chuck which securely retains the array. Conductive wires are bonded to a row of micro-devices.
BRIEF DESCRIPTION OF THE DRAWINGS
The features of the present invention and the manner of attaining them, will become apparent, and the invention itself will be understood by reference to the following description and the accompanying drawings, wherein:
FIG. 1 is a top plan, partial view of an array of micro-devices made according to the present invention;
FIG. 2 is a schematic view of a pick-up tool according to the present invention, used in handling the array of FIG. 1;
FIG. 3 is a top plan view of the array of FIGS. 1 and 2, showing two plates (in dashed lines) of the pick-up tool in magnetic attachment to the array;
FIG. 4 is top plan view of the array of FIG. 1 shown positioned on a hard surfaced magnetic chuck, in preparation for wire bonding and separation;
FIG. 5 is a partial top plan view of the array of FIG. 4 showing a first column of micro-devices subsequent to wire bonding but before separation from the array;
FIG. 6 is another partial view of the array of FIG. 5, subsequent to separation of the first wire bonded column of micro-devices, and further showing a second column of micro-devices subsequent to wire bonding but before separation from the array; and
FIG. 7 is a top plan view of an alternative embodiment for an array of micro-devices made according to the present invention.
Similar numerals refer to similar elements in the drawings. It should be understood that the sizes of the different components in the figures may not be in exact proportion, and are shown for visual clarity and for the purpose of explanation.
DESCRIPTION OF THE INVENTION
FIG. 1 represents a partial view of an array 10 formed according to the present invention. The array 10 is composed of a plurality of micro-devices, such as 12 , 14 , 16 , 18 disposed in a matrix of rows and columns. Adjacent micro-devices, 12 , 14 , 16 , 18 are separated by predefined distances, and are interconnected by means of a plurality of links, such as 20 , 22 , 24 , 26 , so as to facilitate the handling and processing of the entire array 10 prior to separating the individual micro-devices 12 , 14 , 16 , 18 .
In a preferred embodiment, the array 10 is further comprised of a matrix of strips, such as 30 , 32 , 34 , 36 , 38 that are networked to impart added overall tensile strength to the array 10 . The strips 30 , 32 , 34 , 36 , 38 are interconnected, and are further connected to the links 20 , 22 , 24 , 26 . The strips 30 , 32 , 34 , 36 , 38 are made of magnetic material such as nickel iron (NiFe), to permit the handling of the entire array 10 by means of a magnetic pick-up tool 40 (FIG. 2 ), and its placement on a hard surface magnetic chuck 44 (FIG. 4) for processing and subsequent separation of the individual micro-devices 12 , 14 , 16 , 18 .
Considering now the array 10 in more detail, it is formed using thin film processes. According to one such process, a thin metallic film of approximately 1000 Å is sputter or evaporation deposited on a wafer 45 (FIG. 2 ). The wafer 45 is then electroplated to form an etchable layer of copper approximately 3 to 20 microns thick. Aluminum oxide is then sputter deposited onto the layer of copper. The desired micro-devices 12 , 14 , 16 , 18 are then formed as desired. The micro-devices 12 , 14 , 16 , 18 may be magnetic coil assemblies as described in the U.S. patent application titled “Magnetic Coil Assembly”, Ser. No. 08/844,003, or any other thin film device.
To this end, the wafer 45 is masked, and the aluminum oxide layer is then selectively etched to delineate the micro-devices 12 , 14 , 16 , 18 and the connecting links 20 , 22 , 24 , 26 . The fabrication of the micro-devices 12 , 14 , 16 , 18 is then completed as desired, and the wafer 45 is metallized using sputtering or evaporation processes. The wafer 45 is masked and electroplated with a magnetic material, such as NiFe to form the magnetic strips 30 , 32 , 34 , 36 , 38 .
As is illustrated in FIG. 2, the wafer 45 is immersed in a beaker 47 containing an etchant solution 49 , with the array 10 facing upward, for dissolving the etchable layer of copper. When the etchable layer is completely or substantially dissolved by the etchant solution 49 , the array 10 is released from the wafer 45 . The etchant solution 49 is of a composition that selectively etches away copper but not magnetic material (i.e. NiFe). For instance the etchant solution 49 may have the following composition: 58 grams/liter (NH 4 ) 2 S 2 O 8 −20 milliliters/liter NH 4 OH. A magnetic pick-up tool 40 is used to lift the entire array 10 for further processing.
With further reference to FIG. 3, the pick-up tool 40 includes two plates 55 , 57 (shown in dashed lines) formed of soft magnetic material. A removable bar electromagnet 59 is positioned on a handle 61 , in contact with the plates 55 , 57 for applying a magnetic field at the distal ends 65 , 67 of the plates 55 , 57 , respectively. The magnetic field generated by the pick-up tool 40 attracts the magnetic strips 30 , 32 , 34 , 36 , 38 , etc. of the free or released array 10 . The two plates 55 , 57 are preferably positioned opposite each other to minimize the warping of the array 10 .
The handle 61 is optional and enables the user to obtain a convenient grip on the pick-up tool 40 . Alternatively, the entire handling process may be automated and the pick-up tool will be robotically maneuvered. In another embodiment where the array 10 does not include the strips 30 , 32 , 34 , 36 , 38 , the released array 10 may be lifted manually or robotically. In yet another embodiment the pick-up tool 40 is formed of more than the two plates 55 , 57 . For instance, two additional magnetic or non-magnetic plates may be included for added support.
Upon lifting of the array 10 from the etchant solution 49 , the array 10 is rinsed and dried. Excess photoresist material, if any, is dissolved, and the array 10 is rinsed and dried again, as needed.
Thereafter, and as illustrated in FIG. 4, the array 10 is positioned on, and transferred to a smooth, hard surfaced magnetic chuck 44 , which retains the array 10 firmly for further processing and testing, as required. The magnetic chuck 44 is formed of a plurality of adjacently disposed laminates 72 , 73 , 74 , 75 etc., with alternating poles (N, S). Adjacent laminates 72 , 73 , 74 , 75 are secured together, for instance by bonding, along a plurality of bond or adhesive lines, such as 82 , 83 , 84 , 85 , etc. The laminates 72 , 73 , 74 , 75 are made of a suitable magnetic material, such as bonded neodymium iron boron.
The magnetic chuck 44 has an upper surface or side 90 which is ground to a finished smooth surface upon which the array 10 is transferred. It should however be clear to a person of ordinary skill in the field that three other sides or surfaces 92 , 94 , 96 of the magnetic chuck 44 may be used for holding additional arrays 10 . As a result, if practicable, it is possible to simultaneously use more than one surface of the magnetic chuck 44 , thus further accelerating the post-release processing of the array 10 .
Preferably, the laminates 72 , 73 , 74 , 75 are identical and are as closely spaced as possible so as to increase the holding strength of the magnetic chuck 44 . In one embodiment the width “w” of each laminate is approximately 80 mils (where 1 mil equals {fraction (1/1000)} inch).
With reference to FIGS. 5 and 6, a certain number of micro-devices, i.e., 112 , 114 , 116 , 118 in one or more columns (or alternatively one or more rows) are bonded to corresponding wires. For example, two bonding pads 121 , 123 of micro-device 112 are bonded to conductive wires 125 127 . If required, the micro-devices 112 , 114 , 116 , 118 are then tested, even though these micro-devices may have been previously tested on the wafer fabrication level.
The wire bonded micro-devices 112 , 114 , 116 , 118 are then coated with conformal coating, such as ultra-violet curable epoxy, for added protection, which coating is then cured. The micro-devices 112 , 114 , 116 , 118 are then separated from the array 10 , either individually or as a group. The separation may be performed manually by either pulling on the wires, i.e., 125 , 127 , or by means of a vacuum or magnetic pick-up tool, leaving undesired structures, such as the links, i.e., 130 , 132 , 134 , 136 , 140 , 138 , 142 , and the strips, i.e., 30 , 32 , 34 , 144 on the magnetic chuck 44 . To this end, each link, for instance link 138 has two oppositely disposed attachment and breakoff sites 151 , 153 , one of which, i.e., 151 , is connected to the micro-device 112 , for providing a connecting link to hold the array 10 together as well as a natural break location, so that when the individual micro-device 112 is separated from the array 10 , the break off point or site 151 is predictable.
The separated micro-devices 112 , 114 , 116 , 118 are ready for use since they are not attached to undesired structures. Furthermore, since a laser is not used for the separation of the micro-devices 112 , 114 , 116 , 118 , it is now possible to avoid the deleterious aspects of the laser cutting process, such as application and cleaning of adhesive and laser burrs formed during the ablation of the alumina material. Also, after laser cutting and adhesive cleaning, the individual micro-devices 112 , 114 , 116 , 118 are co-mingled with the dross, requiring tedious separation and handling. The separation of the micro-devices 112 , 114 , 116 , 118 may also be done robotically.
According to one embodiment of the present invention the micro-devices 12 , 14 , 16 , 18 , 112 , 114 , 116 , 118 are magnetic coil assemblies, each of which is approximately 200 by 800 microns with a thickness of approximately 20 microns. The length of each link 20 , 22 , 24 , 26 , 130 , 132 , 134 , 136 , 138 , 140 , 142 is approximately 200 microns. The strips 30 , 32 , 34 , 36 , 38 , 144 traverse the entire surface of the array 10 , and preferably, but not necessarily, they intersect each other at approximately 90 degree angles, to form a planar support grid or mesh 155 with the links 20 , 22 , 24 , 26 , 130 , 132 , 134 , 136 , 138 , 140 , 142 . The grid 155 adds tensile strength to the entire array 10 , and creates a magnetic path to allow the magnetic pick-up tool 40 to be used to lift the array 10 after its release from the wafer 45 . Furthermore, the grid 155 forces the array 10 against the magnetic chuck 44 . As an example, the strip 34 is approximately 170 microns wide.
FIG. 7 illustrates another array 200 of micro-devices 12 , 14 , 16 , 18 , which is made according to another embodiment of the present invention. The array 200 is similar to the array 10 , and is fabricated using similar processes, with the exception that the array 200 does not include the magnetic strips 30 , 32 , 34 , 36 , 38 , 144 .
It should be understood that the geometry, compositions, and dimensions of the elements described herein may be modified within the scope of the invention. Other modifications may be made when implementing the invention for a particular environment. In addition, while the invention has been described in connection with coil assemblies other devices may be fabricated using the present method.
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A method of forming and handling an array of micro-devices such as thin film devices that enables simultaneous mass handling and processing of these thin film devices. A plurality of micro-devices and links are simultaneously formed on a wafer, with the links interconnecting the micro-devices for maintaining a unitary array structure. A matrix of magnetic strips is then formed to impart added overall tensile strength to the array. The magnetic strips are secured to the links and form a planar support grid therewith. The array of micro-devices is then released from the wafer and lifted therefrom by means of a magnetic pick-up tool. Using the pick-up tool, the array is transferred onto a magnetic chuck which securely retains the array. Conductive wires are bonded to a row of micro-devices which are then separated from the array into individual micro-devices.
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This is a division of application Ser. No. 07/658,208, filed Feb. 19, 1991.
BACKGROUND OF THE INVENTION
(1. ) Field Of The Invention
The present invention relates to rosin ester resins modified with a hydroxy functional polymer such as an acrylic polymer. More specifically, this invention relates to acrylic polymer modified esters of rosin, methods for preparing the modified rosin, as well as the use of an acrylic polymer modified rosin ester in vehicles for gravure printing inks.
(2. ) Description Of The Prior Art
Modified rosins have come into widespread use as binders in vehicles for gravure printing inks. However, these inks are usually quite costly. In addition, with the development of the printing arts, the speeds of printing have become increasingly high, and requirements for various ink properties such as gloss, drying properties, blocking holdout, firm formation, film toughness (resistance to abrasion), reducibility and printability, color development, resistance to static movement or rub are of primary importance to the resin supplier. All of these properties are affected by the resin or binder used to formulate these inks.
Prior to this invention rosins have been modified with one or more (in succession) or with a combination of dienophiles, and/or with phenolic resins and often followed by esterification in attempts to produce tougher, glossier inks that are resistant to rub. The beneficial product characteristics provided by rosin esters for various uses have led to the development of many esterification procedures, particularly treatments with polyhydric alcohols. U.S. Pat. No. 2,369,125 to Jones, et al. and U.S. Pat. Nos. 2,572,086 and 2,590,910 each to Wittcoff, et al. teach rosin esterification with glycerol and pentaerythritol, among other polyhydric alcohols.
In U.S. Pat. No. 2,478,490 to Krumbhaar, there is disclosed rosin-modified, phenol/formaldehyde resins containing rosin esterified by polyhydric alcohols and reinforced by polybasic acids of the maleic type which are useful in printing inks. These rosin-modified phenol/formaldehyde resins and rosin-modified maleic esters are prepared by heating rosin together with phenol/formaldehyde condensates, with maleic-type polybasic acids, or both, and subsequently esterifying with polyhydric alcohol.
Japanese Patent 62-265,376 to Toray Ind. discloses printing ink compositions containing rosin modified phenolic resins with a polyfunctional acrylate. The Japanese patent does not disclose a modified resin that has been esterified. U.S. Pat. No. 4,693,846 to Piccirilli, et al. discloses a urethane-modified dimerized rosin ester for use in lithographic printing inks and coatings.
There exists a need in the art of gravure printing for an ink which is inexpensive and exhibits good properties in such parameters as film toughness (resistance to abrasion), blocking, color development, gloss, resistance to static movement or rub, high hold out and excellent printability when printed on a given substrate. All of these properties are affected by the resin or binder used to formulate the ink.
Accordingly, it is a primary object of this invention to provide rosin resins and resinates which produce superior gravure printing inks and avoid unsatisfactory physical properties.
Another object of this invention is to provide improved modified rosin resins and resinates for use in printing ink formulations.
Yet another object of this invention to provide a process for making modified rosin resins and resinates which are particularly useful as a component of printing ink vehicles.
It is a further object of this invention to provide a gravure printing ink containing a modified rosin or resinate as a binder which exhibits improved film toughness, gloss and Sutherland rub.
Other objects, features and advantages of the invention will be apparent from the details of the invention as more fully described and claimed.
SUMMARY OF THE INVENTION
The present invention is a modified rosin prepared by forming an adduct of rosin and a dienophile, reacting the rosin adduct with a polyfunctional hydroxy compound to form as ester and reacting the ester with an acrylic-containing polymer to form a hard resin. In an alternative embodiment, a resinate is formed from the hard resin intermediate by blending the reaction product of a rosin adduct, a copolymer, and the hard resin, followed by reaction with zinc in a hydrocarbon solvent. The present invention also includes a gravure printing ink having a vehicle comprising, as the binder, a modified rosin ester resin or resinate of this invention in a hydrocarbon solvent and a pigment dispersed therein.
It has been found that the gravure printing ink formulations in accordance with this invention ink significant increases in rub resistance, abrasion and high gloss, and provide quality printing.
DETAILED DESCRIPTION OF THE INVENTION
The rosins employed in this invention may be tall oil rosin, gum rosin, or wood rosin. Rosin is mainly a mixture of C 20 , fused-ring, monocarboxylic acids, typified by levopimaric and abietic acids, both of which are susceptible to numerous chemical transformations.
Tall oil rosin is isolated from crude tall oil obtained by acidulation of the "black liquor soap" skimmed off the concentrated alkaline digestion liquor washed out of paper pulp in the kraft, i.e. sulfate, pulping process for making paper. Fractionation of the crude tall oil yields tall oil rosin and fatty acids. The tall oil rosin used in this invention generally contains at least about 80% rosin acids, preferably at least about 85% to 88% rosin acids, and most preferably about 95% to 97% rosin acids. It should be understood, however, that the invention contemplates the use of tall oil rosin having rosin contents much lower, for example, about 30% rosin acids. The remaining material is fatty acids and unsaponifiable material.
Gum rosin is produced by the nature separation and gradual conversion of some of the hydrophilic components of sap and related plant fluids from the cambium layer of a tree into increasingly hydrophobic solids. Pine gum contains about 80% gum rosin and about 20% turpentine.
Wood rosin is obtained by resinification of oleoresin from either natural evaporation of oil from an extrudate or slow collection in ducts in sapwood and heartwood. Pine tree stumps are valuable enough to be extracted with hexane or higher-boiling paraffins to yield wood rosin, wood turpentine, and other terpene-related compounds by fractional distillation.
To produce the hard resin intermediate for resinate production, rosin is charged to a reactor and heated until melted, usually about 180° C. The reaction can be conducted in a vessel properly equipped with a thermometer, stirrer, and a distillation column to separate water that distills from reactants, and, optionally, a Dean-Stark trap. The molten rosin is agitated as soon as the melting process makes it possible, and agitation is continued throughout the process.
A dienophile is added to the molten rosin, and the mixture is heated to cause a Diels-Alder (cycloaddition) reaction between the dienophile and the rosin. The preferred dienophiles for reaction with the rosin component are fumaric acid, maleic acid, acrylic acid, methacrylic acid, itaconic acid, citraconic acid and maleic anhydride. It is possible to substitute other dienophiles therefor although they are less preferred. Preferably, the dienophiles are used in an amount of from about 3% to about 20% by weight of rosin and, more preferably, comprises from about 5% to about 15% by weight of rosin.
The reaction temperature should be in the range of between the melting point of the rosin and the boiling point of the dienophile. Thus, the optimum reaction temperature will be selected depending upon the rosin and the dienophile used, generally from about 150° C. to about 250° C., with from about 200° C. to about 210° C. being preferred. Heating is continued until a rosin adduct is produced having an acid number of from about 210 to about 220, which usually takes from about 1 to about 3 hours. The reaction may be carried out under a blanket of inert gas, such as nitrogen.
Upon completion of the reaction, the rosin adduct is reacted with a polyfunctional alcohol and the acrylic-containing polymer to form a modified rosin ester resin.
The rosin adduct is also reacted with an acrylic-containing polymer. Typical acrylic-containing polymers include a polymer mixture of acrylic acid, methacrylic acid, or one or several of their organic ester derivatives, and a member selected from the group consisting of styrene, alpha methyl styrene, ethylene vinyl acetate, and a combination thereof. A preferred polymer is styrene-acrylic polymer, such as Joncryl® 587, available from S. C. Johnson. Generally, from about 10% to about 50% by weight of the acrylic-containing polymer, preferably from about 20% to about 40%, is reacted.
The reaction can be conducted most successfully at temperatures of 200° C., to 300° C., preferably about 200° C. to about 210° C., until a desired acid value and/or hydroxyl value is attained. Lower temperature can be employed, but the rate of reaction will be slowed thereby. Also, higher temperature can be employed, but temperatures above the point at which distillation of reactants or the final product result will affect yield deliteriously. Solvents such as azeotropic solvents such as toluene or xylene or high boiling hydrocarbons can be employed. Catalysts such as condensation catalysts, e.g., dibutyltin oxide or butyl stannoic acid, can also be employed in the reaction. The reaction can be conducted in a vessel properly equipped with a thermometer, stirrer, a distillation column to separate water that distills from reactants, and, optionally, a Dean-Stark trap.
In the preparation of the rosin esterification product, polyfunctional hydroxy compounds are reacted with the rosin adduct. The polyfunctional hydroxy compounds useful herein are preferably polyhydric alcohols. The polyhydric alcohols are preferably high functional polyols. By high functional polyols, it is meant those polyols containing more than two hydroxyl groups which will react with the acid functional reactants to produce rosin esters having high softening points and good dilutability with hydrocarbon solvents. The polyol may contain substituents, provided that the substituents do not adversely affect the reaction of the polyols or the performance of the resultant products. Illustrative examples of these polyols are mono-or poly-pentaerythritol such as di- or tri-pentaerythritol. Other examples of the useful polyols are trimethylolpropane, trimethylolethane, glycerine and the like. Useful polyfunctional alcohols include those alcohols containing at least one hydroxyl group and another functional group that can react with the acid functional group of the rosin.
In the preparation of the hydroxyl-functional esterification product, the particular reactants and reaction conditions that are used will dictate the particular ratio of reactants. The reactants are employed in such a ratio that the resultant esterification product is hydroxyl-functional. Typically, the equivalent ratio of the acid functional reactant to the polyol can be from about 0.8:1.2 to 1:1.2.
The polyfunctional hydroxy compound and a defoamer, if needed to preclude excessive foaming, is charged to the reaction vessel by mixing the polyfunctional hydroxy compound with the catalyst and dividing the mixture into several equivalent portions which are added uniformly over a limited time period while the temperature in the reaction vessel is held above about 180° C., preferably above about 185° C. After addition of the polyfunctional hydroxy 8compound and, optionally, an alkaline catalyst, the reaction vessel is heated to from about 200° C. to about 275° C., preferably about 200° C. to about 210° C., uniformly over a period of about three hours. This heating is designed to maximize the esterification of the rosin resin. Uniform heating minimizes sublimation of the polyfunctional hydroxy compound. Heating is continued at the same temperature until an acid number of 155 is reached.
The resultant polymer-modified ester of rosin generally has good dilutability in appropriate hydrocarbon solvents. The physical properties of the modified rosin ester resin made by the process of the present invention include:
______________________________________Acid Number 145-155Melt Point(°C.) 110-120Viscosity (50% in Toluene) P-T (Gardner scale)Color (50% in Toluene) 10 max.______________________________________
The invention resinate is formed by making a rosin-dienophile adduct, preferably by heating the rosin with maleic anhydride at about 160° C. for an hour. Paraformaldehyde may be added to accelerate the reaction.
To the rosin-dienophile adduct are added an acrylic-containing copolymer, in an amount from about 10% to about 50% by weight of rosin adduct, and the polymer-modified ester of rosin prepared above, in an amount from 2% to about 10% by weight of rosin adduct, and the mixture is blended.
The blend is reacted with a slurry of a reactive zinc compound dissolved in a hydrocarbon solvent. Suitable reactive zinc compounds include metallic zinc or oxides or hydroxides of zinc. The reaction temperature depends upon the rosin adduct and the reactive zinc compound, generally at under reflux or at temperatures from about 200° to about 280° C. The reaction can be accelerated using a catalyst, such as, dibutyltin oxide or butyl stannoic acid. The desirable amount of the zinc compound, based on the adduct, is the reaction equivalent or less. Generally, from about 2% to about 8% by weight, particularly from about 4% to about 7% by weight, based on the weight of the rosin adduct of zinc is reacted. It should be understood that magnesium oxide and/or calcium hydroxide (lime) may replace part or all of the zinc in this reaction. Hydrocarbon solvents, such as those generally used as vehicles in printing inks may be used to form the hydrocarbon slurry.
Another aspect of this invention is to form a solution rosin resinate utilizing the good dilutability characteristics of the modified rosin ester resinate. A convenient method is to dissolve the resinate into a hydrocarbon solvent, such as benzene, toluene, xylene, and mixtures thereof, in situ. The amount of hard resin which will dissolve will vary depending upon the solvent used.
The resinates of this invention generally have good dilutability in hydrocarbon solvents and, preferably, exhibit the following properties:
______________________________________Bulk Viscosity 25° C. (Brookfield, Cps) 2000-4000Color, Gardner 10-17% Non-Volatiles 45-65Gardner Viscosity, 25° C. R-Z2Melt Point, °C. 170-235Acid Number 40-70______________________________________
The printing inks formulated in accordance with the present invention include the modified rosin ester resinate dissolved in an organic solvent as the printing ink vehicle. These printing inks are made in the same manner as conventional printing inks except the resin of the present invention is employed in the ink vehicle. Optionally, the inks may include other ingredients which are typically used in printing inks. The pigments used in the printing inks are well-known to those of ordinary skill in the printing art.
The ink compositions generally are prepared by dispersing, pigment, clay, hydrocarbon solvent, metalated resinate, lecithin and a small amount of an organic compound in a mill. This dispersion is reduced with a mixture of conventional resinate, cellulose, alcohol solvent, hydrocarbon solvent, and the resin vehicle of the present invention to produce an excellent printing ink particularly suitable for use in publication gravure printing.
The most common mixing ratio of the vehicle, pigment and reinforcing filler is as follows:
______________________________________ Desirable Optimum Extent Extent______________________________________Vehicle (wt. parts) 60-97 80-90Pigment (wt. parts) 3-40 10-20______________________________________
The mixing ratio may be varied according to the use of the ink, so that the present invention is not intended to be limited to the above ranges.
These resin/resinates when used as either grind-type or let down-type vehicles, or both, in inks offer significant increases in rub, abrasion, and gloss with no detriment to other pertinent properties of the ink film. Abrasion resistance, as measured on a Taber Abrasion Tester, may increase by 200-300% when used at equal amounts against more conventional resin/resinates. Sutherland Rub Test also shows increases of 50-100% with 10% increase in gloss as well as equal blocking.
The following examples are provided to further illustrate the present invention and are not to be construed as limiting the invention in any manner. All parts are parts by weight unless otherwise stated.
EXAMPLE 1
A hard resin precursor was formed by adding to a suitable reaction kettle under a nitrogen blanket, 10,000 pounds of tall oil rosin. The rosin was heated to 170° C. and the nitrogen turned off, at which time 1,000 pounds fumaric acid was added. The reaction mixture was heated at 210° C. for about two hours (until a clear pill was formed) to form a complete rosin adduct. To the rosin adduct was added 150 ml of DCA Antiform and 3,350 pounds of acrylic-styrene polymer (Joncryl 587) and the heat maintained for 15 minutes. Four pounds of lime was added and the mixture held at 195° C. for one hour. Two hundred pounds of glycerine was added and heating continued at 205° C. until an acid number of 155 was reached.
EXAMPLE 2
A resinate modified with a modified rosin resin was produced by reacting rosin and maleic anhydride at 160° C. for one hour in the presence of a small amount of paraformaldahyde to accelerate the reaction. To the maleic rosin adduct, dissolved in toluene, was blended an ethylene vinyl acetate copolymer and 5% by weight of the hard resin precursor from Example 1. This mixture was cooled to 90° C. and a slurry containing ZnO/MgO was reacted, followed by reaction with lime to form the invention resinate. The temperature of the resinate was increased to reflux, and the resinate dehydrated. The physical properties of this product are:
______________________________________Color, Gardner 12-13Dilution 102 ml/100 gm% Non-Volatile 48Gardner Viscosity, 25° C. Z-Z1Melt Point, °C. 190______________________________________
The solution resinate of Example 2 was tested for rub, abrasion, and gloss with no detriment to other pertinent properties of the ink film. Abrasion resistance was measured on a Taber Abrasion Tester and increased 200-300% when used at equal amounts against more conventional resin/resinates. Sutherland Rub Test also showed increases of 50-100% with 10% increase in gloss as well as equal blocking.
While the invention has been described and illustrated herein by references to various specific materials, procedures and examples, it is understood that the invention is not restricted to the particular materials, combinations of materials, and procedures selected for that purpose. Numerous variations of such details can be employed, as will be appreciated by those skilled in the art.
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A binder for use in gravure printing ink formulations comprising a modified rosin ester resinate prepared by forming a rosin-dienophile adduct, reacting the adduct with a polyfunctional hydroxy compound to form an ester and reacting with an acrylic-containing polymer to form a hard rosin ester. The polymer-modified rosin ester resinate is formed by reacting the prepared hard rosin ester with a rosin-dienophile adduct and an acrylic-containing polymer, reacting the product thereof with reactive zinc, followed by a reaction with lime, dehydrating the resinate product by refluxing, and adjusting its viscosity with a hydrocarbon solvent.
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BACKGROUND OF THE INVENTION
This invention relates to a ground cover suitable for persons to sit on or lie on the ground. This cover is particularly suitable for use on the beach where persons are swimming in the water and then returning to sit or lie on the ground cover.
The types of ocean front properties vary widely from broad sandy beaches to small pebbles and even to large rocks. Ground covers used for these types of beaches vary widely and the most common is the standard "beach towel" which is merely a large terry cloth towel large enough for persons to sit or lie on and avoid direct contact with the sand or pebbles or rock of the beach. If the beach surface is sand, the terry cloth quickly becomes wet and when a person sits on it, the sand or soil beneath the terry cloth becomes adhered to the back. This soils the cloth or at least causes substantial discomfort to any person lying on the towel after it has become wet and soiled. Further, terry cloth provides insufficient protection and comfort when the beach is composed of small pebbles or stones. Terry cloth, particularly when it is wet does not provide a comfortable cover for the ground. Terry cloth is even less suitable if the beach is composed of large rocks.
On the other hand, a nonporous cover such as vinyl plastic, plasticized to make it flexible is again not suitable. Plasticized polyvinyl chloride, even reinforced with fabric, provides no "breathing" and tends to trap moisture both above and below the layer. On a warm day, the person lying on a nonbreathing surface will suffer great discomfort due to the accumulation of moisture and heat between the body and the plastic surface. Further, moisture will accumulate on the bottom surface of the plastic surface giving it a cold and "clammy" feeling. Even multiple ply constructions using a moisture trapping surface such as the plasticized polyvinyl chloride film suffers from the same difficulties, even if it is fixed to a porous fabric ply. While vinyl film provides protection in colder whether, it is not "comfortable" to the touch and becomes uncomfortable again, during use, due to entrapment of moisture. Vinyl film, even when it is reinforced with fabric, is easily punctured and torn by sharp objects found on the ocean beaches and is particularly not suitable for rocky surfaces.
An additional difficulty on beaches is that the breeze or wind tends to lift the corners of the cover causing items resting on the cover to be lost. The breeze tends to overturn the cover bringing the top surface in contact with the ground, causing it to pick up sand or dirt to the great discomfort of the user. Prior devices have used pegs to hold down the corners, but these are extremely dangerous to persons stepping on or tripping over these pegs.
Pockets have been provided in beach towels to hide the persons belongings while the owner is swimming or away from the cover. These covers have utilized openings where the pocket opens below the towel into a hole beneath the towel. This is uncomfortable and not practical in most locations.
The above needs have not been satisfied by the covers in the prior art and none of the present covers satisfy the objects listed herein below.
SUMMARY OF THE INVENTION
It is an object of the present invention to provide a ground cover, suitable for persons to sit or lie on, providing protection between them and the ground.
It is a particular object of the present invention to provide a cover with the ultimate in comfort with ease of portability.
It is a further objection of the present invention to provide a cover as above wherein weights are fixed at the corners to prevent lifting of the corners by the wind, but yet concealing the weights and cushioning them between two layers of fabric preventing harsh contact and possible injury resulting by careless use of the cover.
It is a further object of the present invention to provide a cover wherein a protected pocket is concealed between the two fabric layers being out of sight and difficult to locate.
It is a further object of the present invention to provide a cover with multiple layers, each with absolute compatibility wherein they will shrink and wear cooperatively, prolonging the life of the cover.
It is a particular object of the present invention to provide a cover that will provide the ultimate in comfort, particularly with relation to moisture. It is an object of this invention to provide a cover that will absorb moisture from the body and yet provide a reasonable degree of moisture protection from absorption from the ground below and yet through its construction, dissipate the moisture and prevent its collection between the body and the cover, regardless of the source of the moisture.
It is a particular object of the present invention to provide a cover that is durable and not easily torn or ripped, despite rugged use on sharp or unyielding terrain.
It is another object of the present invention to provide a cover that provides protection from moisture from the grounds but yet also resists attracting sand and dirt to the bottom surface.
It is a particular object of the present invention to provide a cover that provides a cushioned layered structure with an essentially non-slip surface ideal for use on hard surfaces such as the ceramic or the tile around swimming pools or on hard rock surfaces near beaches.
It is a particular object of the present invention to provide a breathable cover that will not attract moisture between the ground and the cover and between the reclining person and the cover.
It is an additional object of the present invention to provide a cover that is suitable not only for warm weather use but is also effective as a cover over the person acting as a comforter or a blanket during cooler weather or during the evenings.
This invention is a ground cover, also referred to as a coverlet, suitable for use by persons sitting or lying on the cover which is placed directly on the ground. It is particularly useful at beaches and on picnics where protection is necessary and comfort is important. An important element of this invention is a two ply cloth construction including a cotton terry cloth top ply and a cotton twill cloth bottom ply. It is preferred that both plies be 100% cotton. Weights, preferably metal weights and more preferably lead weights are fixed at each corner of the cover sandwiched between the two plies. Stitching is used to sew the two plies together to form an integral cover and to fix the weights in each corner. Holes, surrounded by grommets are positioned proximate to each corner and are preferably positioned about one-half to two inches from the corner. A pocket including a waterproof fabric pouch opens at an edge of the cover to the space between the two plies. A fabric hook and eye closure, marketed under the trademark VELCRO®, by Velcro USA, Inc., 681 5th Avenue, New York City, N.Y. is used to close the pocket along the edge of the cover. It is preferred that the VELCRO strips be along the entire length of the pocket opening along the edge of the cover. At least one clip device is included to detachably connect a hole in the cover to a hole in an adjacent cover placed next to it in the ground.
It is preferred that a waterproof bag be provided of a size that the cover can be folded up and fit easily inside including a draw string closure of the bag, a carry strap attached to the top and side of the bag of a length to be slung over a person's shoulder and a patch pocket on the outside of the bag with a VELCRO closure.
While two ply fabric covers have been used for certain applications, such as covers for fenders of automobiles to protect the fenders from mechanics dirt and abrasion of the surface, those constructions are insufficient and unsatisfactory for use by a person as a ground cover. A ply of terry cloth coupled with a ply of impervious material, such as plasticized polyvinyl chloride and other like materials are unsatisfactory for use as a ground cover. While the impervious layer will prevent moisture from reaching the terry cloth from below, moisture collects on the bottom of the vinyl surface. The moisture collects dirt and is unsatisfactory when the cover is picked up to be stored away. Further, the impervious layer provides a distinct lack of comfort to the person lying on the terry cloth side of such a structure. The impervious layer again tends to collect moisture between the terry cloth and the person quickly making the surface very uncomfortable. The combination fabric layers of the invention as above, on the other hand, provides an unusual degree of comfort providing a balance of absorption and of moisture dissipation where under most circumstances. Resting on the cover remains comfortable for long periods of time. Thus, sunbathing on the beach or lying at a picnic is now an even more comfortable diversion. Further, even with this very important advantage, the other objects noted above are attained and satisfied.
It is further found that a person resting on the cover of the present invention with a wet bathing suit allows the upper terry cloth layer to absorb the moisture drawing it away from the body. Further, perspiration from the body or moisture from a recent swim is quickly absorbed into the terry cloth layer. The moisture, on the other hand, does not remain entirely in the terry cloth layer but is dissipated between the layers and to the lower layer further assisting in the evaporation process. Surprisingly, the moisture attracted by the lower layer dissipates sufficiently that it does not attract substantial sand or dirt to the lower surface. The structure of the twill fabric further essentially prohibits invasion of the sand or dirt particles into the interior of the structure between the plies. Even two layers of terry cloth forming a two ply structure do not attain the advantages and results described hereinabove.
While many of the uses and advantages described for the present invention involve going to the beach or around some body of water, it should be understood that many of the advantages and objects of the present invention involve uses and needs that it do not involve water or at least those uses not directly involving swimming or getting the body wet before lying on the ground cover. These uses include but are not limited to camping, picnics, sunbathing in the yard, and any other outdoor activity including the use of the cover as a comforter or blanket during the winter months, whether used indoors or outdoors.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of a cover of the present invention folded up and exploded out of a carrying bag of the present invention.
FIG. 2 is a perspective view of the cover of the present invention with the terry cloth side up.
FIG. 3 is a perspective view of the cover of the present invention with the cotton twill layer facing upwardly.
FIG. 4 is a partial expanded cross-sectional view taken along line 4--4 FIG. 2.
FIG. 5 is a perspective view of a hidden pocket opened to illustrate interior of the pocket positioned along the edge of the cover view along line 5--5 of FIG. 2.
FIG. 6 is a partial cross-sectional view taken along line 6--6 of FIG. 2.
FIG. 7 is a perspective view of two covers as illustrated in FIG. 2 coupled together with clips to form a combined larger ground cover.
FIG. 8 is a partial cross-sectional view taken along line 8--8 of FIG. 7.
FIG. 9 is a perspective view of the clip used in FIGS. 7 and 8 to hold covers together at the corners.
DESCRIPTION OF PREFERRED EMBODIMENTS
In FIG. 1, cover 10 is folded into a package sufficiently small to be inserted in bag 12 constructed of waterproof material, such as fabric reinforced plasticized polyvinyl chloride film or like material constructed in the shape of a bag with opening 14 closed with draw string 16 threaded around and allowed to pull free except for an attachment at the middle to close the bag. Carry strap 18 is attached permanently at the opening top of bag 12 near opening 14 with the other end of strap 18 connected through snap spring clip 20 to a ring permenantly fixed to the side of bag 12 near the opposite closed end of bag 12. Pocket 24 is constructed as a patch pocket sewn on the side of bag 12 approximately in the middle with flap 26 extending over the pocket opening and fixed with VELCRO connectors to close the pocket. As further illustrated in FIGS. 2 and 3, cover 10 is constructed of two plies, the top fabric ply being of 100% cotton terry cloth 12 ounce weight. It is preferred that the weight of the terry cloth be in the range of 7 to 14 ounce weight and more preferred in the range of 10 to 14 ounce weight. Fabric weight is given in ounces, that being the weight of a lineal yard of the fabric with a 45 inch width. The terry cloth may be patterned, but it is preferred to be a solid color and is preferred to be white. The bottom surface, as illustrated in FIG. 3, is a fabric ply of 100% cotton twill cloth having a weight of 8 ounces. It is preferred that the cotton twill cloth be in the weight of 5 to 14 ounces and more preferably in the range of 7 to 12 ounces. It is further preferred that the color be a dark solid color and most preferably dark blue. In each corner, reinforcement of 200 denier waterproof oxford nylon cloth is sewn in a triangular piece to cover the corners and reinforce them in high wear areas. The stitching is provided along each edge sewing the two plies together as well as sewing the corner reinforcements 32 in place. Grommets 34 reinforce holes proximate to each corner and are preferably positioned in the range of one-half to two inches from the corners. The combination of 12 ounce terry cloth and 8 ounce twill cloth provides a most effective barrier against moisture as well as an absorbent construction to absorb body or swim suit moisture without sacrificing comfort. This combination and construction attains the objects described above and attains the balance of characteristics not achieved with other constructions. In FIG. 4, the cross-sectional view illustrates the construction of cover 10 wherein terry cloth ply 28 and twill cloth ply 30 extend all the way to the corners and are reinforced with corner swatches 32 of nylon cloth. Grommets 34 reinforce holes 36 and lead disc weights 38 are sandwiched between plies 28 and 30, held in position by a sewing stitch and further protected by corner reinforcement plies 32. Lead weights 38 are about one-eighth inch thick and weigh one to two ounces.
In FIG. 5, pocket 40 has been opened to display a portion of its interior constructed of waterproof cloth 42, preferably fabric reinforced plasticized polyvinyl chloride film and more preferably 200 denier oxford nylon cloth. Pocket 40 is constructed between plies 28 and 30 and sewn with its opening toward edge 48. VELCRO closures, fabric hook and eye fastening systems marketed under the trademark VELCRO® by Velcro USA, Inc. 681 5th Avenue, New York City, N.Y. are sewn in place as continuous strips along edge 40 to close pocket 40. "Hook" tape 44 engages "eye" tape 46 to provide an invisible but easily openable pocket. As further illustrated in FIG. 6, pocket 40 is constructed of a continuous ply of waterproof cloth 42 sandwiched between fabric plies 28 and 30 closed by VELCRO closures 44 and 46 along edge 48. In FIG. 7, cover 10 is shown lying on the ground next to identical cover 10A. Overlapped as shown, covers 10 and 10A are connected using spring clip 50 on the top and spring clip 52 on the bottom. Thus, with at least one spring clip supplied with each cover 10, combinations with identical covers will form a large area for cooperative enjoyment on the ground. Covers 10 and 10A may be joined side by side as illustrated in FIG. 7 or may be joined end to end using the adjoining holes 36 and the two clips. Further, if a third cover 10 is added, it may be joined again side by side or may be joined end to end with one of the covers to form a variety of patterns. Engagement and connection of two covers is illustrated in the cross-sectional view of FIG. 8 wherein clip 52 joins two covers through holes 36 reinforced by grommets 34. FIG. 9 is an expanded view of a suitable clip connect blankets 10 and 10A together through holes 36.
In order to illustrate the advantages of this invention, a coverlet was constructed according to that illustrated in FIGS. 1 through 6. A second coverlet is constructed of two plies of terry cloth, each ply being 12 ounces weight. A third coverlet is constructed of a single ply of terry cloth 12 ounces in weight sandwiched to a second ply of fabric reinforced plasticized polyvinyl chloride film of fifteen mil thickness. The vinyl film is plasticized according to upholstery standards and is constructed to have the softest "feel" available from this type of material. The three coverlets are stretched on the ground first on sand near the ocean and then on good quality grass cover, typical of that around residential home. After sitting on the ground unattended for about one hour, the third coverlet accumulates a substantial amount of moisture on the bottom attracting bits and pieces of the ground as well as a number of insects on the grass covered ground. The first and second covers are dry on the bottom. Next, each of the covers are subjected to three persons sitting and lying on the coverlets in wet bathing suits. Only the first coverlet of the present invention provides total comfort. The second coverlet immediately soaks through directly to the ground, picking up sand from the beach and vegetable matter and dirt from the lawn location. The person sitting on the third coverlet is very uncomfortable from a heat accumulation wherever the coverlet is rested upon. Further, the plies of the third coverlet tend to slide against each other providing substantial discomfort and difficulty in getting comfortable. The plies of the second coverlet become "melded" together by the accumulated dampness to form substantial discomfort under the person. When the coverlets are lifted after use, only the first coverlet is essentially clean and ready to be moved from the scene without substantial cleaning.
While this invention has been described with reference to the specific embodiments disclosed herein, it is not confined to the details set forth and the patent is intended to include modifications and changes which may come within and extend from the following claims.
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A coverlet suitable for placing on the beach or ground or use as a bed cover, includes two plies, one of cotton terry cloth and the bottom ply of cotton twill cloth. The corner reinforcements with holes allow each coverlet to be interconnected with clips to form larger shapes with a hidden pocket opening to an edge of the coverlet closed by VELCRO strips, supplied in a waterproof bag constructed of waterproof fabric with a draw string closure, shoulder carrying strap and patch pocket closed with VELCRO.
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FIELD OF THE INVENTION
[0001] The present invention relates to tools and tool assemblies for mining and construction, more particularly, is concerned with retention of wear sleeves within a bit holder of the tool assembly.
BACKGROUND INFORMATION
[0002] Rotatable cutting tools are used in conjunction with a machine used to break up (or cut) a substrate such as coal, rock, asphalt pavement, asphaltic concrete, concrete or the like. In its very basic aspects, such a machine includes a driven member (e.g., a chain, a wheel or a drum), a holder either directly or indirectly mounted to the driven member, and a rotatable cutting tool rotatably held in the holder. It is the cutting tool that impinges the earth strata so as to break it into pieces and chunks upon impact.
[0003] Rotatable cutting tools and the holders operate in a high wear environment. These components inevitably fail due to the severity of the operating conditions; e.g. gritty, dusty and highly abrasive. While it is expected that the cutting tools experience wear, the ability of the cutting tool to rotate about its central longitudinal axis during operation generally prolongs the useful life of the cutting tool. Rotation promotes more even wear about the tool. It can thus be appreciated that features of the cutting tool or cutting tool assembly that facilitate the rotation of the cutting tool during operation are beneficial to the operation of the cutting tool (and cutting tool assembly) and the overall operation of the cutting machine.
[0004] As known to those skilled in the art, the useful life of the holder is much longer than the useful life of the cutting tool. A holder is often referred to as a part of a block. Accordingly, the term “holder” refers herein to a portion of a block or a block which holds a cutting bit. Each block is intended to accommodate many changes of cutting tools before the block must be changed. In order to reduce the wear on the forward face of the block and fretting between the block and the cutting bit, a wear sleeve may be used in conjunction with cutting tool and holder. The wear sleeve generally has a forward portion and shank and is positioned between the cutting tool and holder. The wear sleeve protects the block from wear and is removably mounted in the holder.
[0005] Although it is beneficial to promote rotation of the cutting tool, rotation of the wear sleeve in the bit holder is not desirable. As dust and/or debris works in between the bit holder and the wear sleeve, rotation of the wear sleeve encourages abrasion between the bit holder and the wear sleeve.
[0006] One such cutting tool that teaches a protective wear sleeve is shown and described in U.S. Pat. No. 7,270,379 to Stehney. Stehney '379 teaches a sleeve mounted in a holder block which utilizes a stepped configuration on the shank of the sleeve to create an interference fit between the holder block and the sleeve. The interference fit retains the sleeve within the holder block and prevents rotation within the sleeve of the holder block.
[0007] Another cutting tool that uses a protective wear sleeve is shown and described in U.S. Pat. No. 5,106,166 to O'Neill. O'Neill '166 teaches a wear sleeve with an index pin between the collar of the wear sleeve and the forward face of the block. O'Neill '166 also prevents rotation of the wear sleeve by utilizing a pin through an aperture through a shank of the block. The pin passes through the block and contacts a flat surface machined into the wear sleeve. In another embodiment, O'Neill '166 teaches non-rotation of the wear sleeve by using a hexagonally-shaped sleeve shank and block bore.
[0008] U.S. Pat. No. 5,273,343 to Ojanen teaches a non-rotatable wear sleeve. Ojanen '343 describes a wear sleeve for mounting a cutting tool in a bit holder. The deformed sleeve has one end shaped as an ellipse. The deformed sleeve is then force fit into a bore in the block and is retained therein in a non-rotating manner by friction. U.S. Pat. No. 5,303,984 to Ojanen teaches a non-rotatable sleeve for use in a block. Ojanen '984 teaches a diametrically compressible sleeve mounted in the bore of the block. The sleeve has an axial slot which allows it to be compressed from a diameter larger than the given diameter before insertion into a bore of the block and a compressed diameter substantially matching the given diameter after insertion into the bore of the block.
[0009] Numerous other teachings disclose similar devices and methods. Each teaching suffers from one or more of the following deficiencies. The wear sleeves must be replaced regularly as they wear out so convenient installation and extraction is important. However, the protective sleeve must also be secured in the bit holder so as not to be knocked loose by loads and torques that occur during normal operation of the cutting machine.
[0010] Another cutting tool that uses a protective member is shown and described in U.S. Pat. No. 6,508,516 B1 to Kammerer. The '516 Patent discloses a ring that includes a tab. The tab engages grooves in a holder so that the ring does not rotate relative to the holder. At the beginning of a milling cycle, the structure disclosed in U.S. Pat. No. 6,508,516 to Kammerer would be expected to provide a non-rotatable ring; however, over time the structure may be susceptible to problems. One such problem is that the groove that engages the tab may become clogged with debris. Obviously, this condition could compromise the integrity of the connection between the tab and the groove and result in the loss of the non-rotatable feature of the ring. Another problem is that over the course of operation the tab is exposed along the side of the tool so as to be susceptible to wearing away. The erosion of the tab could compromise the integrity of the connection between the tab and the groove and result in the loss of the non-rotatable feature of the ring.
[0011] The present invention has been developed in view of the foregoing.
SUMMARY OF THE INVENTION
[0012] The present invention provides a block and non-rotating wear sleeve for holding a cutting tool used with mining and construction equipment. A key is used to intersect with notches in the wear sleeve and block at a rear face of the wear sleeve and block to prevent rotational movement between the components. Locating the key and notches at the rear face provides and easily manufactured anti-rotation means which is also sheltered from the most of the abrasion experienced by the block and wear sleeve.
[0013] An aspect of the present invention provides an apparatus for mounting a cutting tool used in mining and construction, comprising a block comprising a holder portion having an interior surface defining a bore disposed about a longitudinal axis and passing through the holder portion, the bore extending from front face of the holder portion to a rear face of the holder portion, and at least one slot in the rear face of the holder portion; a wear sleeve having a forward portion adjacent the front face of the holder portion and a shank extending through the bore of the holder portion, the shank having a rear end with at least one notch therein; at least one key engaging the at least one slot of the holder portion and the at least one notch of the shank of the wear sleeve, thereby preventing rotational movement of the wear sleeve relative to the holder portion; and means for retaining the wear sleeve in the holder portion.
[0014] Another aspect of the present invention provides a wear sleeve for use in a mining, road working or earth moving cutting tool, the wear sleeve comprising a generally cylindrical shank disposed about a longitudinal axis having an exterior surface, a rear end and a forward end; a forward portion attached to the forward end of the shank, the forward portion having a shoulder which transitions from a first diameter corresponding to the exterior of the shank to a second larger diameter and a taper front surface; an inner surface defining a bore disposed about the longitudinal axis and extending axially through the forward portion and shank; at least one notch in the rear end of the shank; and a circumferential groove within the exterior surface of the shank which intersects the notch at the rear end of the shank.
[0015] Yet another aspect of the present invention provides an apparatus for mounting a cutting tool used in mining and construction, comprising a block comprising a holder portion having an interior surface defining a bore disposed about a longitudinal axis and passing through the holder portion, the bore extending from front face of the holder portion to a rear face of the holder portion; a wear sleeve having a forward portion adjacent the front face of the holder portion and a shank extending through the bore of the holder portion, the shank having a rear end; means for preventing rotation of the wear sleeve within the holder portion, wherein the means for preventing rotation is integrated into the rear face of the holder portion and the rear end of the shank of the wear sleeve; and means for retaining the wear sleeve in the holder portion.
[0016] These and other aspects will become more apparent from the following description.
BRIEF DESCRIPTION OF THE DRAWINGS
[0017] FIG. 1 is a side view of a base assembly including a block and wear sleeve according to one embodiment of the present invention.
[0018] FIG. 2 rear view (from left in FIG. 1 ) along the longitudinal axis of the base assembly of FIG. 1 showing a keyed ring for preventing rotation of the wear sleeve according to one embodiment of the present invention.
[0019] FIG. 3 is a cross section of the base assembly shown in FIG. 1 according to one embodiment of the present invention.
[0020] FIG. 4 is a side view of a wear sleeve according to one embodiment of the present invention.
[0021] FIG. 5 is a rear view (bottom in FIG. 4 ) of the wear sleeve shown in FIG. 4 .
[0022] FIG. 6 is a keyed ring according to one embodiment of the present invention.
[0023] FIG. 7 is a split ring for retaining the wear sleeve according to one embodiment of the present invention.
[0024] FIG. 8 is a rear view along the longitudinal axis of base assembly wherein a key traverses two opposing notches in the wear sleeve and two opposing notches in the block according to one embodiment of the present invention.
[0025] FIG. 9 is a side view of a wear sleeve utilized in the embodiment shown in FIG. 8 .
[0026] FIG. 10 is an isometric view of a wear sleeve utilized in the embodiment shown in FIG. 8 .
[0027] FIG. 11 is a rear view along the longitudinal axis of base assembly wherein a key traverses a notch in the block and a notch in the wear sleeve and wherein the key is attached to the retaining ring according to one embodiment of the present invention.
[0028] FIG. 12 is the retaining ring with attached key of FIG. 11 .
DETAILED DESCRIPTION
[0029] For purposes of the following detailed description, it is to be understood that the invention may assume various alternative variations and step sequences, except where expressly specified to the contrary. In this application, the use of the singular includes the plural and plural encompasses singular, unless specifically stated otherwise. In addition, in this application, the use of “or” means “and/or” unless specifically stated otherwise, even though “and/or” may be explicitly used in certain instances.
[0030] As used herein, the terms “channel”, “slot” and “notch” are similarly defined as an indentation in a surface and may include not only depressions in a surface but also slots defined by raised portions of the surface. The use of the terms “channel”, “slot” and “notch” within this specification is intended to instructive as to location of the element, e.g., at the wear sleeve or at the holder portion within an embodiment and is not intended to limit the terms beyond the definition given above.
[0031] Referring now to FIG. 1 , a base assembly 10 is shown. The base assembly 10 includes a block 20 which mounts onto a rotating drum or other piece of equipment (not shown). The block 20 will often include a pedestal portion 22 and holder portion 24 . The pedestal portion 22 is configured to allow the block 20 to be attached to the drum or other piece of equipment. In the embodiment shown in FIG. 1 , the pedestal portion 22 has a curved bottom congruent to the shape of a drum exterior. The congruent shape allows the pedestal portion 22 to be easily welded onto the drum. The holder portion 24 includes a front face 52 and a rear face 54 . The holder portion 24 portion of the block 20 has a bore 26 between the front face 52 and the rear face 54 . The bore 26 allows the shank 34 of a wear sleeve 30 to be inserted into the holder portion 24 . The bore 26 and wear sleeve 30 are generally disposed about a central longitudinal axis 2 . The wear sleeve 30 also has a forward portion 32 . The forward portion 32 often has a shoulder 42 which transitions from a first diameter of a shank 34 of the wear sleeve 30 to a second, larger diameter of the forward portion 32 . The forward portion 32 may also have a tapered front surface 44 . The wear sleeve 30 is structured and arranged to accept a cutting tool (not shown) having a shank which fits inside the wear sleeve 30 and a forward tip made from hard materials such as cemented tungsten carbide, polycrystalline diamond or other suitable material. The rear portion of the shank 34 of the wear sleeve projects axially from the bore 26 . The portion of the shank 34 of the wear sleeve 30 which projects from the holder portion 24 includes a circumferential groove about the shank 34 . One or more retaining rings 50 are fitted into the circumferential groove 36 to hold the wear sleeve 30 within the bore 26 . Although the configuration of a circumferential groove and retaining ring is shown in this particular embodiment, other configurations are possible, such as various types of radial projections or recesses on the holder portion 24 or wear sleeve, press fits snap fits, mechanical fasteners and the like.
[0032] Referring now to FIG. 2 , a rear view of the base assembly 10 is shown. The retaining rings are not shown in this figure to allow a clearer description of other components of the base assembly 10 . As noted above, the shank 34 of the wear sleeve 30 is inserted into the bore 26 . The bore 26 has a counter bore 70 in the rear face 54 of the holder portion 24 . Also, shaped into the rear face 54 is a radial slot 72 . An axial slot 40 is defined in the rear section of the shank 34 of the wear sleeve 30 . The axial slot 40 corresponds to the radial slot 72 of the holder portion 24 . A keyed ring 60 comprises a ring section 62 and key section 64 . The keyed ring 60 is sized to slide axially over the shank 34 of the wear sleeve 30 and into the recess created by the shank 34 and the counter bore 70 . As seen in FIG. 2 , the keyed portion 64 extends radially outward into the radial slot 72 of the holder portion 24 . The keyed portion 64 also extends radially inward into the axial slot 40 of the shank 34 of the wear sleeve 30 . This configuration interlocks the shank 34 with the holder portion 24 and prevents rotational movement of the wear sleeve 30 .
[0033] Placing the keyed ring 60 at the rear face 54 of the holder portion 24 keeps it in a protected location away from the more severe abrasive effects at the front of the wear sleeve 30 and holder portion 24 . In contrast, prior art, non-rotational means at the forward portion of the wear sleeve 30 and holder portion 24 are prone to failure before the wear sleeve 30 . The keyed ring 60 and slots 40 , 72 also provide an easily fabricated base assembly 10 . Earlier designs utilizing press fits, interference fits or other means inside the bore 26 are difficult and expensive to machine. In contrast, the slots 40 , 72 and keyed ring 60 are easily fabricated.
[0034] FIG. 3 is a cross-section of the block assembly 10 shown in FIGS. 1 and 2 . The sleeve bore 38 may have a recess 80 for retaining the cutting tool (not shown). The keyed ring 60 may fit wholly or partially in counterbore 70 . The key 64 extends from the radial slot 72 of the holder portion 24 into the axial slot 40 of the shank 34 .
[0035] Referring now to FIG. 4 , a side view of the wear sleeve 30 is shown according to one embodiment of the present invention. Although the forward portion 32 shows a tapered front surface 44 and shoulder 42 , other configurations known to those skilled in the art are possible.
[0036] A single axial slot 40 is shown in the shank 34 of the wear sleeve 30 . FIG. 5 shows a rear view of another embodiment of a wear sleeve according to one embodiment of the present invention having additional axial slots 40 a, 40 b, 40 c about the shank 34 of the wear sleeve 30 . It should be appreciated that with the additional axial slots, 40 a, 40 b, 40 c, may be rotated or indexed so that any of the axial slots would correspond to the radial slot 72 of the holder portion 24 and key 64 of the keyed ring. In another embodiment, other axial slots 40 a, 40 b, 40 c, may be present and correspond to additional keys on the keyed ring 60 which also correspond to additional radial slots within the holder portion 24 . In yet another embodiment, the wear sleeve 30 may have a single axial slot 40 and the keyed ring 60 may have a single key 64 while multiple radial slots are located within the holder portion 24 . It should be noted that slots may extend partially or wholly through the holder portion or wear sleeve. It should further be noted that, although the rear view of the wear sleeve 30 shown in FIG. 5 shows a circular forward portion 32 , the forward portion 32 may be any suitable shape.
[0037] FIG. 6 illustrates a keyed ring 60 according to one embodiment of the present invention. The keyed ring 60 has a radius, r, dimensioned to allow the keyed ring 60 to pass over the shank 34 of a wear sleeve 30 . Key 64 is dimensioned to fit within the axial slot of the wear sleeve 30 and the radial slot of the rear face 54 of the holder portion 24 . As mentioned in the preceding paragraph, multiple keys may be located about the ring 62 to further secure the wear sleeve 30 from rotation or to accommodate other embodiments of the present invention.
[0038] FIG. 7 shows a retaining ring 50 according to one embodiment of the present invention. The retaining ring 50 may be a tapered section retaining ring as shown with lugs 52 at each end of the retaining ring 50 . Ring pliers may be used to engage the lugs and expand the split ring 50 over the shank of the wear sleeve so the split ring 50 can be seated in the circumferential groove of the wear sleeve. Although a particular type of ring 50 is shown in FIG. 7 any suitable fastener may be used, e.g., other ring style or a threaded section with a nut.
[0039] FIGS. 8-10 show another embodiment of the present invention without a counterbore or ring recessed in the rear face of the holder portion. Referring now to FIG. 8 , the base assembly 110 may include a block 120 with a holder portion 124 and a pedestal portion 122 . As with earlier described embodiments, a shank 134 of a wear sleeve fits within the bore 126 and extends beyond the rear face 154 of the holder portion 124 . In this embodiment, the key 164 spans across the notches 140 the rear end 146 of the shank 134 of the wear sleeve and extend into channels 172 of the holder portion 124 . A circumferential groove 136 (shown in FIG. 9-10 ) about the shank 134 of the holder portion 124 provides a seating surface for installation of one or more retaining rings. The retaining rings retain the wear sleeve in the holder portion 124 and retain the key 164 in the notches 140 of the wear sleeve and channels 174 of the holder portion 124 . FIGS. 9-10 show isolated views of the wear sleeve 130 . Notches 140 extend beyond the circumferential groove 136 so that the retaining ring fits over the key 164 . It should be appreciated, that other key, channel and notch configurations are possible.
[0040] Referring now to FIGS. 11-12 , a rear view of a base assembly 210 is shown. In this embodiment, a key 264 is attached to the retaining ring 250 . An additional keyed ring is not necessary. It is also not necessary to have a counterbore in the holder portion 224 . The retaining ring 250 seats within a circumferential groove of the wear sleeve 246 (not shown in FIG. 11 ) at an axial position external to the bore of the holder portion 224 . Wear sleeve 246 and holder portion 224 may be disposed about a longitudinal axis 2 . In this embodiment, protrusions 274 extend from the rear face 254 to define a slot 276 between the protrusions 274 . The key 264 extends from the wear sleeve notch 240 to the slot 276 defined by the protrusions 274 . The protrusions 274 may be forged as an integral part of the holder portion or affixed in some other fashion known to those skilled in the art. Although no keyed ring is used in this embodiment, it should be appreciated that a combination with a keyed ring, protrusions, and retaining ring is also possible.
[0041] Whereas particular embodiments of this invention have been described above for purposes of illustration, it will be evident to those skilled in the art that numerous variations of the details of the present invention may be made without departing from the invention as defined in the appended claims.
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A block and non-rotating wear sleeve for holding a cutting tool used with mining and construction is disclosed. A key is used to intersect with notches in the wear sleeve and block at a rear face of the wear sleeve and block to prevent rotational movement between the wear sleeve and block. Locating the key and notches at the rear face provides an easily manufactured anti-rotation means which is also sheltered from the most of the abrasion experienced by the block and wear sleeve.
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BACKGROUND OF THE INVENTION
The present invention relates to a method for determining the air flow passing through a turbine-engine laybrinth seal.
In turbine-engine operation, especially those utilized for aircraft propulsion, a number of hitherto inexplicable drawbacks have been encountered. Among these drawbacks is a drop in thrust over variable durations, a propensity towards pumping, depending on the temperature of the turbine-engine, and general performance degradation under ill-defined operating conditions.
It has been suggested that these drawbacks may be attributed to variations in air leaks to one or more of the various labyrinth seals utilized in the turbine-engine structure, in particular those labyrinth seals at the compressor output. A method for precisely measuring the air flow through the various labyrinth seals of the turbine-engine is necessary to analyze the behavior of the engine and to interpret the operational thermodynamic conditions of its turbine at high pressure. Also, knowledge of the air flows through the labyrinth seals enables the more precise definition and improvement of break-in procedures.
SUMMARY OF THE INVENTION
The main object of the present invention is to devise a method for directly measuring the air flow through a labyrinth seal, in particular for a turbine-engine, which method is applicable to both the transient and steady states of the engine operation and requires only slight modifications of the engine structure.
The method according to the invention injects a constant flow of inert gas, such as carbon dioxide into the air flow downstream of the labyrinth seal such that the inert gas is mixed with the air flowing through the seal. At a further downstream location, after the inert gas and air have been homogeneously mixed, a sample portion of the mixture is withdrawn and analyzed to determine the concentration level of the inert gas in the sample.
When the method is utilized to analyze the labyrinth seal of the turbine-engine compressor, the inert gas is injected adjacent to the compressor on the downstream side into the volume defined by the compressor stage and inside casing of the engine combustion chamber, the downstream turbine stage, and the shaft interconnecting the compressor with the turbine. The sample portion of the homogeneous mixture is withdrawn adjacent to the turbine stage on the upstream side.
According to the method of the present invention, the air flow through the compressor output labyrinth seal is easily determined from the concentration of the inert gas of the sample mixture. As an example, if the flow rate of the injected inert gas is 0.03 moles/s and if the analysis of the sample portion shows its inert gas concentration to be 0.3%, it is easily deduced that the air flow through the labyrinth seal is:
0.03/0.003=10 moles/s=290 g of air per second.
The test method of the instant invention may be implemented by injecting any gas provided it is chemically inert with respect to the components of air, however, carbon dioxide is the preferred gas. It is quite available, economical, harmless and capable of being stored in large amounts in the liquid state under a pressure of approximately 50 bars. A bottle of liquified carbon dioxide is a highly advantageous source of injection gas for the method according to the present invention since the inert gas leaving the bottle is at a pressure which depends solely on the ambient temperature--not on the contents of the bottle. Also, the carbon dioxide contents in the sample portion can easily be determined by using gas analyzers which are widely available in test facilities for turbine engines.
Since the air mixed with the carbon dioxide in the implementation of the instant method itself contains a specific fraction of carbon dioxide, the latter must be considered when computing the flow rate of the air through the labyrinth seal by measuring the carbon dioxide concentration in the sample portion.
The method according to the present invention may inject the inert gas into the engine structure and may withdraw the sample portion from the engine structure by using pick-up means which are ordinarily present adjacent the compressor output labyrinth seal and the turbine stage for temperature and pressure instrumentation. Generally, when turbine-engines are tested, whether as prototypes or in other development stages, they contain numerous test pickups for instrumentation which measures temperature and pressure at various locations throughout the engine structure. These pickups are usually in the form of small-diameter tubes, several of which are located at the compressor output labyrinth seal and at the turbine stage. These small-diameter tubes may be utilized to inject the inert gas and to withdraw the sample portion.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a schematic diagram of the apparatus for carrying out the method according to the invention.
FIG. 2 is a schematic diagram illustrating the method for measuring the air flow through a labyrinth seal of the compressor output of a turbine engine.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIG. 1, a bottle of inert gas is shown at 1, which may contain 15 kg of carbon dioxide at a pressure of 50 bars when the ambient temperature is 15° C. Conduit 2 is connected to the discharge outlet of the bottle 1 and passes the inert gas through a heating system 3, which may be an electrical heater having a power of 500 w. The inert gas passes into an expansion system 4, of known construction, which is adjustable and is generally set in such a manner that the carbon dioxide arrives at diaphragm 5 at an approximate upstream pressure of 25 bars. The diaphragm 5 serves to further reduce the pressure of the gas to approximately 10 bars. At this reduced pressure, the gas passes into the injection tubes 6, which are illustrated as four in number (6a through 6 ). Although four injection tubes are shown, quite obviously any number of them may be utilized depending upon the precise engine structure. As noted previously, the injection tube 6a-6d may be standard instrumentation pickup tubes already present in the turbine engine as it undergoes its test stages and which are located near the compressor output labyrinth seal. Typically, such small-diameter tubes are less than 1 mm in diameter and are 1 m long. Under these conditions, it can be seen that when the conduit 2 feeds the injection tubes with carbon dioxide at a pressure of 10 bars, the four tubes 6a-6d inject a total carbon dioxide gas flow of approximately 1.36 g/s into the turbine engine.
FIG. 1 also illustrates two of the approximately seven temperature and/or pressure pickup tubes which are provided near the turbine of the engine at 7a and 7b. Each of the two selected pickups are each 1 m long and have a 1 mm inside diameter. The exterior ends of the pickup tubes are connected in parallel to a single sampling conduit 8 which transfers the gas mixture into analyzer 9. The analyzer 9 is of known construction and is capable of determining the molar fraction of carbon dioxide contained in the gas mixture sampled by the tubes 7a and 7b. In a typical example, the two tubes 7a and 7b allow sampling a total gas mixture flow of approximately 0.3 g/s when the turbine engine operates at full speed. In that instance, the pressure generated within the engine is enough to force the sampled mixture into the analyzer 9. However, when the turbine engine operates at lower speeds, the sampling portion pressure is only approximately 1.2-1.3 bars. In this instance, an evacuation pump 10 is connected into the conduit 8 by closing valve 11a and opening valve 11b to draw the sampled mixture through the pickup tubes 7a and 7b and into the analyzer 9. In such a mode of operation, the flow rate of the gas mixture is approximately 0.06 g/s.
In the set-up shown in FIG. 1, a non-negligible overall response time is involved, particularly due to the length of the sampling conduit 8 which may be on the order of 10 m long having an inside diameter of 6 mm. In that event, the response time is approximately 0.6 s at low speed operation and 1 s at full speed. The analyzer 9 itself has a response time of less than 1 s. The pickup tubes, such as 6a-6d, 7a and 7b can be provided on an engine in standard operating conditions to monitor the changes in the clearances of the labyrinth seal, and to determine a maintenance program for these seals as a function of time. This system is shown in FIG. 2, wherein 12 denotes a compressor stage of the turbine engine and 13 denotes the turbine stage of the engine. 14 is a shaft of the high-pressure stage while 15 denotes the inside casing of the combustion chamber. In many turbine engines, the combustion chamber has an annular shape which is defined by inside and outside casings (not shown). Element 15 schematically indicates the inside casing of such an annular combustion chamber. Element 16 denotes the sealed or enclosed volume bounded by the particular elements 12-15 of the turbine engine.
The block 20 in FIG. 2 schematically illustrates the carbon dioxide source and the supply circuit shown in FIG. 1 (elements 1-4) upstream of the diaphragm 5. In this embodiment, the feed conduit 2 branches into an injection system 6 which may comprise the 4 injection tubes 6a-6d of FIG. 1. Element 17 denotes a compressed air tubing located upstream of the compressor output labyrinth seal and which is utilized to withdraw a small amount of compressed air from this stage of the engine and to deliver the air to various devices in the aircraft. A regulating valve 18 controls the flow of air through conduit or tube 17 which may be measured by flow meter 19 located downstream of the regulating valve 18.
A tap 21 branches off the injection system 6 and leads into conduit 17 downstream of the regulating valve 18.
The sampling withdrawal system 7 may comprise the two pickup tubes 7a and 7b, as shown in FIG. 1 which may be connected to the volume 16 a slight distance upstream of the high pressure stage of the turbine 13. In this embodiment, the gas mixture analyzer 9 is a differential analyzer of the Wheatstone bridge type and comprises two input tubes which are connected, respectively, to the sampling conduit 7 and to conduit 22. The other end of conduit 22 is connected to the conduit 17 downstream of the flow meter 19 to withdraw a sample of the air/inert gas mixture from conduit 17. Two of the branches of the Wheatstone bridge of the differential analyzer are affected by the gas mixtures fed to them through the conduit 7 and 22, respectively.
The method of the present invention may be carried out utilizing the system shown in FIG. 2 by comparing the flow rates through various of the conduits. d 1 is the flow rate of the carbon dioxide supplied from the source 20 and injected through the injection conduit 6 into the enclosure 16; d 2 is the flow rate of the carbon dioxide injected through the conduit 21 into the conduit 17 downstream of the regulating valve 18; D 1 is the flow rate of the gas mixture sampled in the enclosure 16 by means of conduit 7; and D p is the flow rate of the gas mixture sampled by the conduit 22 downstream of the flow meter 19. The carbon dioxide is supplied at the same temperature and at the same pressure in conduits 6 and 21, and the flow rates d 1 and d 2 are calibrated by throttleing means such that the ratio d 1 /d 2 remains constant and independent of the respective variation in d 1 and d 2 (the value of the ratio d 1 /d 2 is previously ascertained under test bench conditions). If, then the regulation valve 18 is adjusted so as to balance the concentration in carbon dioxide in the two gas mixtures circulating in the conduits 7 and 22 with the flow rate D 1 and D p , the air flow rate through the output labyrinth seal of the compressor 12 may be calculated by the formula:
D.sub.1 =D.sub.p (d.sub.1 /d.sub.2) (1)
When the operational conditions of the turbine engine change, the Wheatstone bridge of the differential analyzer 9 becomes unbalanced and must be returned to a balanced condition by the adjustment of the regulating valve 18. The error with respect to the air flow through the labyrinth seal D 1 then will not exceed a few percent because it corresponds substantially to the sum of the errors relating to the flows d 1 , d 2 and D p , the latter value obviously being provided by the flowmeter 19.
In a variation of this test method, the differential analyzer 9 may be replaced by a standard analyzer which directly indicates the concentration of the carbon dioxide in the measured gas mixture. The same analyzer may sequentially measure the concentration C 2 of the mixture sampled by the conduit means 7 and then the concentration C 1 of the mixture circulating in the conduit 17 downstream of regulating valve 18 and the conduit 21. In this instance, the air flow through the labyrinth seal at the output of compressor 12 may be calculated as follows:
D.sub.1 =D.sub.p (d.sub.1 /d.sub.2) (C.sub.1 /C.sub.2) (2)
With this method, it is not necessary to adjust the regulator valve 18 to vary the air flow. However, the test results may encounter an additional error due to the measurements of the concentrations C 1 and C 2 during rapidly changing transient states of turbine engine, it may be necessary to use two separate analyzers to simultaneously measure the concentrations C 1 and C 2 . However, this may also entail additional errors due to the discrepancy between the calibrations of the two analyzers and to the different response times of the two conduits to which the analyzers are connected.
The results obtained using the method according to the invention are significant during the development of the turbine engine as well as during its service life. During the development stages, the results obtained lead to better knowledge of the high-pressure turbine efficiency and also to a better knowledge of the operational curve of the engine compressor which enable its pumping tendancies to be reduced. During the service life of the engine, the test results will enable the determination of the effectiveness of the labyrinth seal and will determine its service life.
The foregoing descriptions are provided for illustrative purposes only and should not be construed as in any way limiting this invention, the scope of which is defined solely by the dependent claims.
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A method for determining the air flow through a labyrinth seal of a turbinengine is disclosed wherein a constant flow rate of an inert gas is injected into the air discharged through the compressor output labyrinth seal. A portion of the gas mixture is withdrawn a specific distance away from the injection point and the flow rate of the air discharged from the labyrinth seal is calculated by measuring the inert gas content of the sample mixture.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The invention relates to the field of five valve manifolds and the attached assembly drawings show the general arrangement of two types of five valve manifolds incorporating angle bonnet features according to the invention.
2. Description of the Related Art
Drawing FIGS. 3 , 3 a , 4 and 4 a show the same type of five valve manifold valve with the conventional arrangement of the valve bonnets, wherein:
FIGS. 3 and 3 a show a five valve, flange by pipe manifold with the equalizer and vent valves located on the front face of the manifold.
FIGS. 4 and 4 a show a five valve, flange by flange manifold with the equalizer and vent valves located on the front face of the manifold.
BRIEF SUMMARY OF THE INVENTION
The general type of manifold is used in flow measurement applications in a variety of industries, including oil and gas, petrochemical, water treatment and power production. The manifold valve is installed between the primary flow measurement element (an orifice plate or similar) and the transmitter. The purpose of the primary element is to cause a pressure drop in the pipeline. There is a relationship between the size of the pressure differential caused by the primary element and the flow through the pipeline. A transmitter, typically an electronic device, measures the pressure differential. However, the conventional positioning of the valves on and normal to a front face of the prior art manifolds requires the valve handles to be small in order not to interfere with one another and makes those handles difficult to turn by hand. The present invention overcomes these difficulties by positioning some of the valves in depressions such that the valves are not normal to the front face.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 schematically illustrates a perspective view of one embodiment of the invention of a five valve manifold of the flange by flange type having a general “I-shape”;
FIG. 2 schematically illustrates a perspective view of another embodiment of a five valve manifold of the flange by pipe type having a generally “T-shape”;
FIG. 3 is an elevation view of a prior art flange by pipe five valve manifold;
FIG. 3 a is a right side view of the prior art manifold of FIG. 3 ;
FIG. 4 is an elevation view of a prior art flange by flange five valve manifold; and
FIG. 4 a is a right side view of the prior art manifold of FIG. 4 .
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In such an installation as described above for flow measurement applications, there are two independent passages from the primary element through the manifold valve to the transmitter. One passage 11 is from the high pressure side of the primary element and the other passage 13 is from the low pressure side of the primary element. Two isolation or block valves ( 12 , 14 , respectively, one on each of the high side and low side) are located within the manifold to allow the transmitter (not shown) to be isolated from the pipeline. In all the drawings attached according to embodiments of the invention the isolation/block valves 12 , 14 are located on the sides of the manifold.
The other three valves 16 , 18 , 20 in a five valve manifold are typically located on the front face 22 of the manifold body (see prior art drawings FIGS. 3–4 ). These valves 16 , 18 , 20 are either used as equalizer valves or vent valves. Five valve manifold can have either 2 equalizer valves and one vent valve, or one equalizer valve and two vent valves.
The equalizer valve(s) are used to control communication between the high pressure side passage 11 and the low pressure side passage 13 . When the transmitter is measuring differential pressures the high side and the low side are isolated from each other and thus the equalizer valves are closed. When it is necessary to calibrate the transmitter the equalizer valves are opened, allowing the high side and the low side to be connected. The pressure on both sides is now equalized and the transmitter can be zeroed and calibrated.
The vent valve(s) is used to process fluid to be vented, either to bleed off pressure or to bleed off unwanted accumulations of air, gas or other fluids that would affect the pressure measurement.
In the currently available manifolds of this type these three valves (the equalizer and vent valves) are located on the face 22 of the manifold 10 . FIGS. 3–3 a and 4 – 4 a show this arrangement. The industry standard spacing between the high pressure side and the low pressure of the primary flow measurement element is 2⅛″, center to center. This standard spacing imposes constrains on the location of the equalizer/vent valves 16 , 18 , 20 and forces those valves 16 , 18 , 20 , when located on the face 22 of the manifold 10 to be quite close together. This in turn requires that the handles 16 ′, 18 ′, 20 ′ on those individual valves 16 , 18 , 20 to be quite small in order to prevent the handles from interfering with each other. These manifold valve handles 16 ′, 18 ′, 20 ′ are hand operated. The close spacing of the equalizer/vent valves 16 , 18 , 20 does not allow much room for hand operation of the vent/equalizer valve handles 16 ′, 18 , 20 ′. Further the need for small handles 16 ′, 18 ′, 20 ′ makes those valve handles 16 ′, 18 ′, 20 ′ more difficult to turn by hand.
The invention disclosed in the embodiments of FIGS. 1 and 2 show embodiments of the invention wherein two of these three valves 160 , 180 , 200 located on surfaces 24 , 26 angled off the front face 220 of the manifold body 100 . This permits the handles 160 ′, 180 ′, 200 ′ to be separated allowing for both larger handles and more access room for hand operation. This makes operation of these valves 160 , 180 , 200 both easier and more convenient.
It will be apparent from the foregoing that many other variations and modifications may be made to the invention described herein without departing from the essential concept of the invention. Accordingly, it should be clearly understood that the embodiments of the invention disclosed herein are exemplary only and not intended as limitations on the scope of the present invention.
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A multi-valve manifold is provided, including a valve body having a periphery about which are placed a series of valves. At least one of the series of valves fits within a depression in the valve body.
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FIELD OF THE INVENTION
The present invention relates to a method of making a composite casting having a preformed metallic or intermetallic insert, such as, for example, a reinforcement insert comprising a metal matrix composite, bonded in a preselected position therein.
BACKGROUND OF THE INVENTION
Components for aerospace, automotive, and like service applications have been subjected to the ever increasing demand for improvement in one or more mechanical properties, such as tensile strength, ductility, fatigue life, resistance to impact damage, etc. while at the same time maintaining or reducing the weight of the component. To this end, the Charbonnier et al. U.S. Pat. No. 4,889,177 describes a method of making a composite casting wherein a molten lightweight alloy, such as aluminum or magnesium, is countergravity cast into a gas permeable sand mold having a fibrous insert of high strength ceramic fibers positioned therein by metallic inserts so as to be incorporated into the casting upon solidification of the molten alloy.
The Funatani et al. U.S. Pat. No. 4,572,270 describes a method of making a composite casting to this same end wherein a mass of high strength reinforcing material, such as ceramic fibers, whiskers, or powder, is incorporated into a lightweight metal matrix (e.g., aluminum or magnesium) that is die cast around the reinforcing mass in a pressure chamber.
A technique commonly referred to as bicasting has been employed in attempts to improve one or more mechanical properties of superalloy castings for use as aerospace components. Bicasting involves pouring molten metal into a mold cavity in which a preformed insert is positioned in a manner to augment one or more mechanical properties in a particular direction(s). The molten metal surrounds the insert and, upon solidification, yields a composite casting comprising the insert embedded in and hopefully soundly bonded with the cast metal without contamination therebetween. However, as described in U.S. Pat. No. 4,008,052 attempts at practicing the bicasting process have experienced difficulty in consistently achieving a sound metallurgical bond between the insert and the metal cast therearound without bond contamination. Moreover, difficulty has been experienced in positioning the insert in the mold cavity and thus in the final composite casting within the required location tolerances. The inability to achieve on a reliable and reproducible basis a sound, contamination-free bond between the insert and the cast metal has significantly limited use of bicast components in applications, such as aerospace components, where reliability of the component in service is paramount.
SUMMARY OF THE INVENTION
The present invention provides an improved bicasting type of process for making a composite casting wherein a sound, contamination-free metallurgical bond is reliably and reproducibly produced between a preformed insert and the cast metal therearound.
The present invention involves a method of making a composite casting wherein a casting mold is provided having a melt-receiving mold cavity and a preformed metallic or intermetallic insert located in a predetermined position in the mold cavity. A melt is introduced into the mold cavity about the insert and is solidified to provide a composite casting having one or more interfaces between the insert, or an insert positioning member, and cast/solidified metal about the insert. The interface is exposed on or communicates with an exterior surface of the composite casting so as to thereby communicate with the ambient atmosphere.
After separation from the mold, the composite casting is subjected to a sealing operation to fluid-tight seal the interface(s) at the exterior casting surface. For example, the interface(s) can be sealed by providing fused material at the interface(s) at the exterior casting surface. The fused material can be provided by welding (without filler material) proximate portions of the insert and the solidified melt under vacuum, air, or inert cover gas. Alternately, the fused material can be provided by depositing a weld filler material at the interface(s). However, the invention is not limited to sealing of the interface(s) by welding. For example, the interface(s) can also be sealed by liquid metal sintering, brazing, or other techniques where a fused material is provided, either by melting proximate portions of the insert and cast/solidified melt or by introducing a separate filler material (e.g., a weld filler material or braze material), at the interface(s).
After the interface(s) is (are) sealed, the composite casting is subjected to elevated temperature and elevated isostatic fluid (e.g. gas) pressure conditions effective to produce a sound, void-free, contamination-free metallurgical bond between the insert and the cast melt thereabout. The previously sealed interface(s) prevent the pressurizing fluid from entering and migrating between the insert and the cast/solidified melt so as to enable formation of the sound, void-free, contamination-free bond. The sealed region(s) of the composite casting typically (but not always) is (are) removed and discarded after the bonding operation.
In one embodiment of the invention, the insert is located in the mold cavity with opposite ends thereof extending outside the mold cavity through opposite mold walls or caps. In this arrangement, a peripheral interface is formed between the insert and melt cast and solidified thereabout at opposite ends of the composite casting. These interfaces are sealed in fluid-tight manner as described hereabove.
In another embodiment of the invention, the insert is located in the mold cavity by slender positioning members, such as pins and/or chaplets, between the mold inner walls and the insert. In this arrangement, an interface is formed between each pin and/or chaplet and the melt cast and solidified thereabout at an external casting surface. These interfaces are sealed in a fluid-tight manner as described hereabove.
In practicing the present invention, the insert may comprise a metallic (e.g. Ti alloys) or intermetallic (e.g. TiA1) material which may include reinforcing filaments, particulates, etc. therein. An exemplary preformed insert comprises a metal matrix composite. The metallic or intermetallic material of the insert may correspond substantially in composition to the melt introduced into the mold cavity. The objects and advantages of the present invention enumerated above will become more readily apparent from the following detailed description and drawings.
DESCRIPTION OF THE DRAWINGS
FIG. 1 is a schematic side elevational view of a ceramic shell mold with a performed insert positioned in the mold cavity thereof by opposite ends of the insert being fixed in the mold end wall and mold end closure cap.
FIG. 2 is a schematic side elevational view of the composite casting formed in the mold of FIG. 1 showing the interfaces between the insert and cast/solidified melt at the external end surfaces of the casting.
FIG. 3 is a schematic side elevational view of the composite casting of FIG. 2 after the interfaces shown between the insert and the cast/solidified melt are sealed by filler-less welding.
FIG. 4 is similar to FIG. 3 after regions of the composite casting including the sealed interfaces are removed and discarded.
FIG. 5 is a schematic side elevational view of a ceramic shell mold with a performed insert positioned therein by slender pins and chaplets.
FIG. 6 is a schematic side elevational view of the composite casting formed in the mold of FIG. 5 showing some of the exposed and sealed interfaces between the pins/chaplets and the cast/solidified melt.
DETAILED DESCRIPTION OF THE INVENTION
Referring to FIG. 1, a preformed insert 10 is shown positioned in a ceramic investment casting shell mold 20. The mold 20 includes a frusto-conical funnel 22 into which a melt is poured from a suitable source, such as a ladle or crucible, a down sprue 24, and a laterally extending ingate or channel 26 that receives the melt from the down sprue 24. The ingate 26 is communicated to the mold cavity 30 so as to supply the melt thereto to fill the mold cavity 30 and the riser 28 thereabove. The shell mold 20 is fabricated in accordance with conventional shell mold practice wherein a fugitive (e.g., wax) pattern assembly in the configuration of the desired funnel 22, down sprue 24, ingate 26, riser 28 and mold cavity 30 is dipped in ceramic slurry, stuccoed or sanded with dry ceramic particulates, and then dried in repeated fashion to build up the shell mold 30 thereon. The pattern assembly is selectively removed from the shell mold 20 in conventional manner, such as by melting, dissolving, or vaporization of the pattern material. Thereafter, the shell mold 20 is fired at elevated temperature to develop proper mold strength for casting.
The preformed insert 10 is positioned in the mold cavity 30 by its lower insert end 11 being received and adhered in the lower shell mold wall 21 using a ceramic cement or adhesive and by its upper insert end 13 being received and adhered using ceramic cement or adhesive in a closure cap 40 that is fastened in the riser 28 by ceramic adhesive (not shown). The mold may be split into sections which are assembled about the insert and clamped, fastened or other-wise held together to facilitate assembly of the mold and insert. The ceramic closure cap 40 is considered part of the mold 20. It is apparent that a central region or portion 15 of the insert 10 is thereby located in the mold cavity 30 while the opposite insert ends 11, 13 extend out of the mold cavity 30 through the ingate 26 and riser 28, respectively, to the exterior of the shell mold 20.
Alternately, the preformed insert 10 may be positioned in the mold cavity 30 by forming the wax pattern about the insert except for its opposite insert ends 11,13, forming the shell mold 20 about the pattern/insert assembly by the dipping/stuccoing procedure described above so that the insert ends 11,13 are captured in the mold walls formed thereabout, and then selectively removing the pattern to leave the insert 10 located in the mold cavity 30 by its captured ends 11,13. Pattern removal and subsequent mold firing are conducted to prevent oxidation or other contamination of the insert (e.g. using a vacuum or inert gas atmosphere).
The preformed insert 10 may comprise a metallic or intermetallic material that is preformed by conventional fabrication operations, such as casting, powder metallurgy, plasma spraying, forging, etc., in the desired shape for the composite casting to be made. The preformed insert 10 may comprise a metallic or intermetallic material having a composition similar to or different from that of the melt to be cast therearound. The preformed insert 10 may include reinforcements, such as reinforcing particulates, filaments, and the like therein. For example, the preformed insert 10 may comprise a metallic (e.g. Ti Alloy such as Ti-6A1-4V) or intermetallic (e.g. TiA1) matrix reinforced with suit-able reinforcing filaments or particulates. The metal matrix composite may be sheathed with a material compatible with the melt to be cast so as to avoid unwanted reaction between the reinforcement and the cast melt.
After the preformed insert 10 is positioned in the mold cavity 30, a melt of a selected metallic or intermetallic material is poured from a ladle or crucible (not shown) under vacuum into the mold funnel 22 and travels through the down sprue 24 and ingate 26 into the mold cavity 30 and the riser 28 (or other gating configuration). The central region 15 of the preformed insert 10 is thereby surrounded by the melt. Upon solidification of the melt in the mold cavity 30, a composite casting 50 is produced and includes the preformed insert 10 embedded in the cast and solidified melt 52, see FIG. 2.
Following solidification of the melt, the mold 20 including the mold closure cap 25 is removed from the casting 50 by conventional techniques. For example, the shell mold 20 and closure cap 40 are removed by sand-blasting, although other removal techniques may be employed in practicing the invention.
The cast/solidified melt 52 in the mold ingate 26 can be removed from the composite casting 50 either prior to or after further processing. FIG. 2 shows portions of the cast/solidified melt 52 in the ingate 26 removed from the casting 50. The cast/solidified melt 52 in the riser 28 may also be removed in the same manner.
The composite casting 50 thereby produced includes interfaces FF between the cast/solidified melt 52 and the insert 10 at opposite external end surfaces 55,56 of the composite casting. The interfaces FF thus communicate with the exterior surface of the casting 52 as a result of the insert ends 11,13 extending outside of the shell mold 20 as shown in FIG. 1. The inter-faces FF are thereby exposed to the ambient atmosphere at the exterior casting end surfaces 55,56.
These exposed interfaces FF prevent subsequent hot isostatic pressing of the composite casting 50 under elevated temperature/elevated gas pressure/time conditions. Such hot isostatic pressing is effective initially to close any voids which may exist between the preformed insert 10 and the cast/solidified melt 52 therearound and then to effect such diffusion bonding as to insure that a complete, sound metallurgical bond is obtained between the insert and the surrounding cast/solidified melt 52. In particular, the exposed interfaces FF provide a path between the insert 10 and the cast/solidified melt 52 for the pressurizing gas (e.g., argon) to migrate and penetrate and thereby prevent metallurgical bonding between the insert and the cast/solidified melt.
In accordance with the present invention, the composite casting 50 is subjected to a sealing operation to fluid (gas)-tight seal the interfaces FF communicating to the exterior casting end surfaces 55,56. For example, the interfaces FF can be sealed by providing fused material at the interfaces FF. The fused material can be provided by welding (without filler material) proximate portions of the insert 10 and the solidified melt 52 preferably under vacuum (or under inert cover gas depending upon the insert and melt compositions involved). For example, the proximate portions of the insert 10 and the cast/solidified melt 52 can be electron beam welded in vacuum of 1×10 -3 torr (1 micron) to this end to form a gas-tight weld W, see FIG. 3, at the interfaces FF. Alternately, the fused material can be provided at the interfaces FF by depositing an appropriate fused weld filler material at the interfaces FF.
The invention is not limited to sealing of the interfaces FF by welding, however. For example, the interfaces FF can also be sealed by liquid metal sintering, brazing, or other technique, preferably in vacuum to avoid insert contamination, where a fused material is provided at the interfaces FF, either by melting portions of the insert and proximate cast/solidified melt themselves or by introducing a separate fused filler material (e.g., a weld filler material or braze material).
After the interfaces FF are gas-tight sealed, the composite casting 50 is subjected to elevated temperature and elevated isostatic gas pressure for a time effective to close voids and form a sound, void-free, contamination-free, metallurgical bond between the insert 10 and the cast/solidified melt 52. The particular elevated temperature/elevated gas pressure/time conditions used will be tailored to the particular melt composition employed, the insert material employed as well as the size (e.g., cross-section) of the composite casting 50.
The sealed gas-tight interfaces FF are effective to prevent penetration and migration of the isostatic pressing gas, such as argon, along the interfaces FF during the hot isostatic pressing operation. In effect, the insert 10 is sealed inside the cast/solidified melt 52 and does not communicate with the ambient high gas pressure atmosphere present during the pressing operation. As a result, a sound, void-free, contamination-free metallurgical bond is formed between the insert 10 and the cast/solidified melt 52 by the hot isostatic pressing operation.
After the hot isostatic pressing operation, regions of the composite casting 50 including the sealed inter-faces FF may be removed and discarded. For example, the ingate region 75 including the lower sealed interface FF and the riser region 77 including the upper sealed interface FF can be trimmed from the composite casting 50. Typically, the location of the interfaces FF is chosen so to reside on regions of the casting 50 that can be removed in a trimming or similar removal operation, although the invention is not limited in this regard.
EXAMPLE
A ceramic shell mold (e.g., zirconia face-coated zircon shell) similar to FIG. 1 was made in accordance with conventional shell mold practice and included a Ti-6A1-4V preformed insert having a rectangular configuration with opposite ends extending outside the mold. The dimensions of the insert were 0.100 inch ×0.5 inch ×3.0 inch. The shell mold was formed by repeatedly dipping/stuccoing a wax pattern formed about the insert except for the opposite insert ends so that the insert ends are captured in the mold walls formed thereabout. The central region of the insert was thereby located in the mold cavity.
A Ti-6A1-4V melt was cast under a vacuum of less than 5 microns into the mold preheated to 600° F. and solidified in the mold cavity about the insert. The composite casting produced was separated from the shell mold and the interfaces FF between the insert and cast/solidified melt were electron beam welded using a conventional electron beam welder under vacuum of 1 micron (without filler material) to gas tight weld proximate portions of the insert and cast/solidified melt at the interfaces FF. The weld zone was about 0.1 inch in width and penetrated about 0.1 inch in depth into the insert and cast/solidified melt. The sealed composite casting was isostatically pressed at 1650° F. for 3 hours. The pressed casting was metallographically sectioned and found to have a sound. Void-free metallurgical bond produced between the insert and the cast/solidified melt thereabout.
Referring to FIGS. 5 and 6, another embodiment of the invention is illustrated wherein like features of FIGS. 1-4 bear like reference numerals primed. This embodiment differs from the embodiment of FIGS. 1-4 in that the preformed insert 10' is positioned in the mold cavity 30' by slender end pins 100' and side chaplets 110' as shown best in FIG. 5. The end pins 100' are welded to the opposite ends of the insert 10' and are fixed in the lower mold wall 21' and in the mold closure cap 40'. The chaplets 110' are welded to the sides of the insert 10' and extend into abutting engagement with the inner, upstanding mold walls 23'. The chaplets 110' are not fixed in the mold walls, however. The pins 100' and chaplets 110' constitute positioning members for precisely locating the insert 10' in the mold cavity 30' . The pins 100' and chaplets 110' preferably comprise a metallic or intermetallic material having the same or similar, or at least compatible, composition as the composition of the cast melt so as not to degrade the properties of the bicasting.
As is apparent from FIG. 5, the outer ends of the pins 100' extend outside the mold while the outer ends of the chaplets 110' extend into abutting engagement with the mold walls 23'. As a result, when a melt is cast and solidified in the mold cavity 30' , a composite casting 50', see FIG. 6, will be produced having interfaces FF' between each pin 100' and chaplet 110' and the cast/solidified melt 52' proximate thereto. The ends of pins 100' located outside the casting are typically trimmed off flush with the casting exterior surface 60'. The interfaces FF' communicate with the exterior surface 60' of the casting 50'..
Prior to hot isostatically pressing the composite casting 50', the interfaces FF' are sealed in fluid (gas)-tight manner by depositing a weld bead WB over each interface FF', FIG. 6. The weld bead WB can be deposited using an electron beam welding technique and suitable filler material (e.g., Ti for the materials used in the Example set forth hereinabove) to form the weld bead WB.
The gas-tight sealed composite casting 50' can then be hot isostatically pressed in the manner described hereabove to form a sound, void-free metallurgical bond between the insert 10' and the cast/solidified melt 52' thereabout. The weld beads WB are gas tight so as to prevent the pressurizing gas from penetrating and migrating along the interfaces FF'.
The invention provides an improved bicasting type of process for making a composite casting wherein a sound, void-free, contamination-free metallurgical bond is reliably and reproducibly produced between the insert and the cast/solidified melt thereabout.
Moreover, while the invention has been described in terms of specific embodiments thereof, it is not intended to be limited thereto but rather only to the extent set forth in the following claims.
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A method of making a composite casting wherein a casting mold is provided having a melt-receiving mold cavity and a preformed metallic or intermetallic insert located in a predetermined position in the mold cavity. A melt is introduced into the mold cavity about the insert and is solidified to provide a composite casting having one or more interfaces between the insert, or an insert positioning member, and cast/solidified metal about the insert. The interface is exposed on or communicates with an exterior surface of the composite casting. After separation from the mold, the composite casting is subjected to a sealing operation to gas-tight seal the interface(s) at the exterior casting surface. For example, the interface can be sealed by providing fused material at the interface. After the interface(s) is (are) sealed, the composite casting is subjected to elevated temperature and isostatic gas pressure conditions effective to produce a sound, void-free, contamination-free metallurgical bond between the insert and the cast melt thereabout. The previously sealed interface(s) prevent the pressurizing gas from entering and migrating between the insert and the cast melt so as to enable formation of the sound, void-free, contamination-free bond.
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BACKGROUND OF THE INVENTION
A camper cover is heavy and it is generally difficult to drape the cover over a camper. The present invention features a camper system comprising swinging poles to facilitate the draping of a camper with a camper cover.
Any feature or combination of features described herein are included within the scope of the present invention provided that the features included in any such combination are not mutually inconsistent as will be apparent from the context, this specification, and the knowledge of one of ordinary skill in the art. Additional advantages and aspects of the present invention are apparent in the following detailed description and claims.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a side view of the system.
FIG. 1A shows a perspective view of the system, in particular the second plate and assemblies thereon.
FIG. 2 shows a front view.
FIG. 3 shows a side view of the system.
FIG. 4 shows a top view of the system.
FIG. 5 shows a side view of the system wherein the camper cover is clamped to the first and second lift poles and linking bar. The first and second lift poles are at angled toward the first end of the camper.
FIG. 6 shows a side view of the system wherein the camper cover is clamped to the first and second lift poles and linking bar. The first and second lift poles are pulled away from the first end of the camper by a rope.
FIG. 7 shows a side view of the system wherein the camper cover is clamped to the first and second lift poles and linking bar. The first and second lift poles are pulled toward the second end of the camper and the draping of the camper by the camper cover is complete.
DESCRIPTION OF PREFERRED EMBODIMENTS
Referring now to FIG. 1-7 , the present invention features a system 100 for covering a camper 500 . In some embodiments, the system comprises a first base plate 110 having a first front base end 112 and a first rear base end 114 , a first wheel chock 120 disposed at the first front base end 112 , a first bracket 130 disposed along a length 132 of the first base plate 110 , a first screw clamp 140 embracing the first bracket 130 , a first tee 142 fixably disposed on the first screw clamp 140 , a first lift pole 150 pivotably attached to the first tee 142 . In some embodiments, the first lift pole 150 has a first lift pole upper end 152 , a first side clamp 160 disposed on the first lift pole 150 for clamping a first side section 172 of a camper cover 170 to the first lift pole 150 . In some embodiments, the first screw clamp 140 can be secured at a position near a front bracket end 134 , near a middle section of the bracket 136 (as shown in FIG. 3 ) or near a rear bracket end 138 . In some embodiments, a first pin 116 is disposed at the first rear base end 114 .
The system further comprises a second base plate 210 having a second front base end 212 and a second rear base end 214 , a second wheel chock 220 disposed at the second front base end 210 , a second bracket 230 disposed along the length 232 of the second base plate 210 , a second screw clamp 240 embracing the second bracket 230 , a second tee 242 fixably disposed on the second screw clamp 240 , a second lift pole 250 pivotably attached to the second tee 242 . In some embodiments, the second lift pole 250 has a second lift pole upper end 252 , and a second side clamp 260 disposed on the second lift pole 250 for clamping a second side section 174 of the camper cover 170 to the second lift pole 250 . In some embodiments, the second screw clamp 240 can be secured at a position near a front bracket end 234 , near a middle section of the bracket 236 or near a rear bracket end 238 . Due to the difference in length of campers the second screw clamp 240 allows the base plate 210 to be at the center point of the camper. In some embodiments, a second pin 216 is disposed at the second rear base end 214 .
In some embodiments, the system further comprises a cross support 270 having a first cross support end 272 and a second cross support end 274 . In some embodiments, the first cross support end 272 comprises a first aperture 276 and the second cross support end comprises a second aperture 278 , wherein the first base plate 110 and the second base plate 210 are placed side by side to allow the first aperture 276 of the cross support 270 to fit over the first pin 116 and the second aperture 278 of the cross support 270 to fit over the second pin 216 of the first and second base plates, respectively, to lock the first and second base plates together relative to each other. In some embodiments, the system further comprises a linking bar 280 connecting the upper end of the first lift pole 152 and the upper end of the second lift pole 252 . In some embodiments, a top clamp 282 is disposed on the linking bar 280 for clamping a top section 176 of the camper cover 170 to the linking bar 280 .
To cover the camper 500 with the camper cover 170 , the camper 500 is parked with its wheels 510 rested on the first 110 and second 210 base plates and up against the first 120 and second 220 wheel chocks. The first side clamp 160 , top clamp 282 and second side clamp 260 are used to clamp onto a camper cover 170 at the first side section 172 , top section 176 and second side section 174 of the camper cover 170 , respectively. To start, the first 150 and second 250 lift poles are angled toward a first end of the camper 520 , then the first 150 and second 250 lift poles are swung toward the second end 522 of the camper and causing the camper cover 170 to drape over the camper 500 .
In some embodiments, the first lift pole 150 comprises multiple connecting sections 154 . In some embodiments, the second lift pole 250 comprises multiple connecting sections 154 . In some embodiments, the cross support 270 comprises multiple connecting sections 279 . In some embodiments, the linking bar 280 comprises multiple connecting sections 284 . In some embodiments, the connection sections are tubes comprising a male end and a female end, where a male end 600 of one section can be fitted with a female end 610 of another section to form a longer tube, see FIG. 1 insert for example.
In some embodiments, a rope 300 is attached to the linking bar 280 to swing the first 150 and second lift pole 250 from the first end 520 of the camper toward the second end 522 . In some embodiments, a launching pole 400 is used to push and lift the linking bar from the first end 520 of the camper toward the second end 522 , see FIG. 5 for example.
As used herein, the term “about” refers to plus or minus 10% of the referenced number.
Various modifications of the invention, in addition to those described herein, will be apparent to those skilled in the art from the foregoing description. Such modifications are also intended to fall within the scope of the appended claims. Each reference cited in the present application is incorporated herein by reference in its entirety.
Although there has been shown and described the preferred embodiment of the present invention, it will be readily apparent to those skilled in the art that modifications may be made thereto which do not exceed the scope of the appended claims. Therefore, the scope of the invention is only to be limited by the following claims.
The reference numbers recited in the below claims are solely for ease of examination of this patent application, and are exemplary, and are not intended in any way to limit the scope of the claims to the particular features having the corresponding reference numbers in the drawings.
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A camper cover is heavy and it is generally difficult to drape the cover over a camper. The present invention features a camper system comprising swinging poles to facilitate the draping of a camper with a camper cover.
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FIELD OF THE INVENTION
The present invention relates to portable stages and, more particularly, to portable stages that may be towed by a vehicle.
BACKGROUND OF THE INVENTION
A variety of portable stage structures, which may be towed by vehicles, have been developed. Many of these portable stage structures include a transport configuration (i.e., a position the stage is in when it is being towed) and a deployed position (i.e., a position the stage is in when it is in use). Further, many portable stage structures include a floor (comprised of foldable floor panels) and a canopy (comprised of foldable canopy panels) for covering the floor when the floor and canopy are in their deployed positions.
In prior systems, in order to ensure that the canopy covered the floor when both the floor and the canopy were deployed, canopy panels were designed to fold over their floor panels when the stage was in its transport position. In such systems, because the canopy panels were exposed during transport, the canopy panels were designed to be extremely durable, preventing the canopy panels from being lightweight. Instead, canopy panels tended to be heavy and bulky, adding to the overall weight of the portable stage.
It would be desirable to design a portable stage having a canopy and a floor, wherein (1) the canopy includes canopy panels and the floor includes floor panels, (2) the canopy is large enough to cover the floor when the floor and canopy are in their fully-deployed positions, and (3) the canopy panels are designed to be folded between the floor panels when the stage is in its transport position. Furthermore, it would be advantageous to reduce the overall weight of the stage by constructing the canopy panels from a lightweight material, since the canopy panels would no longer be fully-exposed during transport of the stage.
In many portable stages, hydraulic systems are used to convert portable stages from their transport configuration to their fully-deployed configuration. For example, many portable stages use hydraulic systems to move their canopies from their transport configuration to their fully-deployed configuration. Unfortunately, however, hydraulic systems suffer from a number of drawbacks. Specifically, for example, hydraulic systems are highly susceptible to damage when exposed to extreme temperatures. Furthermore, hydraulic systems may leak and are relatively complex. Even further, hydraulic systems require an onboard or remote power source, which may not always be available or reliable.
Accordingly, it would be desirable to develop a mechanical, as opposed to hydraulic, system capable of deploying a portable stage from its transport configuration to its fully-deployed configuration. Specifically, it would be desirable to develop a mechanical system for deploying a canopy. Even more specifically, it would be desirable to develop a mechanical system which permits a single individual to deploy a canopy from its transport configuration to a deployed configuration. Further, it would be beneficial to develop a mechanical system which permits a canopy from being taken from a parallel configuration relative to a stage floor to an angled configuration relative to the stage floor for drainage, lighting and/or acoustical considerations.
Many portable stages are supplied with supports that are permanently attached to the flooring of the stage to support the stage when it is fully deployed. Supports which are permanently attached to the floor of the stage may make storage and transport of the flooring somewhat cumbersome. In addition, the supports may become damaged during transport or deployment.
Accordingly, it would be desirable to provide a floor support mechanism that is removably attached to the flooring and which makes transport and storage of the flooring more convenient and less susceptible to damage. In addition, it would be desirable to provide flooring and a corresponding floor support mechanism that is safe during set-up, tear-down and transport of the stage.
SUMMARY OF THE INVENTION
The present invention is designed to overcome the aforementioned problems and meet the aforementioned, and other, needs.
A portable stage having at least a transport configuration and a deployed configuration is disclosed. In one embodiment, the portable stage includes a chassis having wheels rotatably attached thereto and a main floor panel attached to the chassis. First and second deployable floor panels are pivotally attached to the main floor panel, and a deployable canopy is attached to the chassis. The deployable canopy is stored between the first and second floor panels when the portable stage is in its transport configuration. When the stage is deployed, the main floor panel, first floor panel and second floor panel form a main stage, and the canopy is large enough to cover the main stage.
In another embodiment, the portable stage includes a chassis having wheels rotatably attached thereto and a main floor panel attached to the chassis. First and second deployable floor panels are pivotally attached to the main floor panel, and a deployable canopy is attached to the chassis. The canopy includes a main canopy panel, a first canopy panel and a second canopy panel, wherein said first and second canopy panels are pivotally connected to the main canopy panel and wherein the first and second canopy panels respectively have first and second spring pins. The main canopy panel includes first and second canopy panel securement plates which cooperate with first and second spring pins to both lock the canopy in its transport configuration and place the canopy in a semi-deployed configuration.
In yet another embodiment, the portable stage includes a chassis having wheels rotatably attached thereto and a main floor panel attached to the chassis. First and second deployable floor panels are pivotally attached to the main floor panel, and a deployable canopy is attached to the chassis. First and second stabilizer beams are pivotally attached to the chassis and are stored under the main floor panel when said portable stage is in its transport configuration. The first and second stabilizer beams may be deployed by being pivoted out from under the main floor panel. Gas struts may be used to position the stabilizer beams. Furthermore, first and second stabilizer beams include apertures for correspondingly receiving stabilizing pins located on first and second floor panels to secure first and second floor panels once they have been deployed.
In yet a further embodiment, the portable stage includes a chassis having wheels rotatably attached thereto and a main floor panel attached to the chassis. First and second deployable floor panels are pivotally attached to the main floor panel. The portable stage also includes a deployable canopy having a main canopy section, which may be lifted relative to the main floor panel. First, second, third and fourth sleeves are fixedly secured to the chassis, wherein the first, second, third and fourth sleeves respectively receive first, second, third and fourth extension beams which are secured to the main canopy panel. The first, second, third and fourth extension beams permit the main canopy panel to be parallel to the main floor panel when in a transport configuration and tilted relative to the main floor panel when in a deployed configuration.
Other embodiments, objects, features and advantages of the invention will be apparent from the following specification taken in conjunction with the following drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1A illustrates a perspective view of one embodiment of the portable stage of the present invention in its transport configuration;
FIG. 1B illustrates a first side view of the embodiment of the present invention shown in FIG. 1A;
FIG. 1C illustrates a second side view of the embodiment of the present invention shown in FIG. 1A;
FIG. 1D illustrates a front view of the embodiment of the present invention shown in FIG. 1A;
FIG. 1E illustrates a rear view of the embodiment of the present invention shown in FIG. 1A;
FIG. 2A illustrates a partial sectional view of FIG. 1A illustrating two of the stabilizer beams when the portable stage is in its transport configuration;
FIG. 2B is a perspective view of one embodiment of the present invention illustrating deployment of the stabilizer beams;
FIG. 2C is a partial view along line 2 C— 2 C illustrating a gas strut connected between the chassis and a stabilizer beam, wherein the gas strut is used to position the stabilizer beam;
FIG. 2D illustrates a partial perspective view of a stabilizer jack which is used to support the stage when the stage is in its deployed configuration;
FIG. 3A illustrates a partial perspective view of the portable stage of FIG. 1A;
FIG. 3B is a perspective view of one embodiment of the portable stage of the present invention illustrating three of the four floor panels in their deployed configuration;
FIG. 3C illustrates a partial perspective view of the first and second floor panels, wherein the floor panel joiner bar is not attached to both the first and second floor panels;
FIG. 3D illustrates a partial perspective view of the first and second floor panels, wherein the floor panel joiner bar is attached to both the first and second floor panels;
FIG. 3E illustrates a perspective view of one embodiment of the portable stage of the present invention with the four floor panels deployed and the canopy in its transport configuration;
FIG. 4A illustrates a partial perspective view along lines 4 A— 4 A of FIG. 3E illustrating second canopy panel securement plate, first spring pin release wire, first spring pin assembly and first canopy pivot shaft;
FIG. 4B illustrates a first side view of FIG. 4A showing the canopy panel securement plate when the first canopy panel is in its transport configuration;
FIG. 4C illustrates a first side view, similar to FIG. 4B, of the canopy panel securement plate when the first canopy panel is in an intermediate position;
FIG. 4D illustrates a second side view, opposite the first side view of FIGS. 4B and 4C, of the canopy panel securement plate when the first canopy panel is in a semideployed position;
FIG. 4E illustrates a first side view, similar to FIGS. 4B and 4C, of the canopy panel securement plate when the first canopy panel is in a fully-deployed configuration;
FIG. 5A illustrates a perspective view of the canopy lifting mechanism of one embodiment of the present invention, with the flooring, stabilizer beams and the chassis removed;
FIG. 5B illustrates a top view of the canopy lifting mechanism of one embodiment of the present invention, with the flooring, stabilizer beams and chassis removed;
FIG. 5C illustrates a cutaway view of a sleeve and an extension beam for one embodiment of the present invention with a stanchion located within both the sleeve and the extension beam;
FIG. 5D illustrates a partial perspective view of one embodiment of an extension beam for the canopy lifting mechanism of one embodiment of the present invention;
FIG. 5E is a top view, similar to FIG. 5B except that the chassis has not been removed, of the canopy lifting mechanism of one embodiment of the present invention, illustrating the preferred position of bell crank assembly relative to chassis;
FIG. 5F illustrates a perspective view of a bell crank assembly for the canopy lifting mechanism of one embodiment of the present invention;
FIG. 5G illustrates a perspective view of a winch for the canopy lifting mechanism of one embodiment of the present invention;
FIG. 5H illustrates a perspective view of a pulley mount for the canopy lifting mechanism of one embodiment of the present invention;
FIG. 6A illustrates a perspective view of a floating pivot for one embodiment of the present invention, wherein the floating pivot is pivotally attached to an extension beam;
FIG. 6B is a phantom view similar to FIG. 6A;
FIG. 6C is a phantom view similar to FIG. 6B, which illustrates two possible positions of many possible positions of the floating pivot;
FIG. 7 illustrates a perspective view of one embodiment of the portable stage of the present invention in its fully-deployed configuration; and,
FIG. 8 illustrates a side view of one embodiment of the portable stage of the present invention in its fully-deployed configuration.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
While this invention is susceptible of embodiments in many different forms, there is shown in the drawings and will herein be described in detail, a preferred embodiment of the invention with the understanding that the present disclosure is to be considered as an exemplification of the principles of the invention and is not intended to limit the broad aspects of the invention to the embodiment illustrated.
FIG. 1A illustrates a perspective view of the portable stage 10 of the present invention wherein the portable stage 10 is in a transport configuration. Similarly, FIGS. 1B, 1 C, 1 D and 1 E are first side, second side, front and rear views, respectively, of the portable stage 10 in a transport configuration. With reference to FIGS. 1A-1E, the portable stage 10 includes a trailer portion 20 and a stage portion 30 , wherein the stage portion 30 is integrated with the trailer portion 20 .
The trailer portion 20 includes a chassis 22 , wheels 24 and a trailer tongue 26 . The wheels 24 are rotatably mounted to the chassis 22 , as is common with towable trailers. The trailer tongue 26 is mounted to the chassis 22 to permit the portable stage 10 to be towed by a vehicle (not shown). Preferably, the components of the portable stage 10 are lightweight, allowing the portable stage 10 to be towed by a sport-utility vehicle or a pick-up truck. For example, many components may be made with 6061 aircraft aluminum or other lightweight materials.
The stage portion 30 includes a floor assembly 100 , a floor deployment assembly 200 , a canopy assembly 300 , and a canopy lifting assembly 400 . The floor assembly 100 includes main floor panel 102 , first floor panel 104 , second floor panel 106 , third floor panel 108 and fourth floor panel 110 . The main floor panel 102 is preferably fixedly attached to chassis 22 and preferably spans over the entire top surface area of chassis 22 . The main floor panel 102 has first side 112 , second side 114 , first end 116 and second end 118 .
The first and second floor panels 104 , 106 are preferably hingeably attached to main floor panel 102 along first side 112 of the main floor panel 102 . Preferably, the combined length of first and second floor panels 104 , 106 is approximately equal to a distance from the first end 116 to the second end 118 of main floor panel 102 . Furthermore, a first dowel 120 , preferably having a length approximately equal to the distance from the first end 116 to the second end 118 of main floor panel 102 , is advantageously used to form part of the hingeable connection between main floor panel 102 and first and second floor panels 104 , 106 , which assists the first and second floor panels 104 , 106 in being in alignment with one another when deployed. As will be understood by those skilled in the art, the remainder of the hingeable connection is conventional.
Similarly, the third and fourth floor panels 108 , 110 are preferably hingeably attached to main floor panel 102 along second side 114 of the main floor panel 102 . Preferably, the combined length of third and fourth floor panels 108 , 110 is approximately equal to a distance from the first end 116 to the second end 118 of main floor panel 102 . Furthermore, a second dowel 122 , preferably having a length approximately equal to the distance from the first end 116 to the second end 118 of main floor panel 102 , is advantageously used to form part of the hingeable connection between main floor panel 102 and third and fourth floor panels 108 , 110 , which assists the third and fourth floor panels 108 , 110 in being in alignment with one another when deployed. As will be understood by those skilled in the art, the remainder of the hingeable connection is conventional.
The floor deployment assembly 200 preferably includes first stabilizer beam 202 , second stabilizer beam 204 , third stabilizer beam 206 , fourth stabilizer beam 208 , fifth stabilizer beam 210 , sixth stabilizer beam 212 , seventh stabilizer beam 214 and eighth stabilizer beam 216 . Each of the stabilizer beams 202 - 216 are preferably pivotally connected to chassis 22 by their respective first ends 218 A- 218 H (only first end 218 A of first stabilizer beam 202 is identified in FIG. 1 B). Further, each of the stabilizer beams 202 - 216 preferably has a stabilizer jack 220 A- 220 H (only first stabilizer jack 220 A is identified in FIG. 1B) either integral with, or connected to, its respective second end 222 A- 222 H (only second end 222 A of first stabilizer beam 202 is identified in FIG. 1 B).
Preferably, pairs of stabilizer beams (e.g., first and second stabilizer beams 202 , 204 ; third and fourth stabilizer beams 206 , 208 ; etc.) are designed to be folded under the main floor panel 102 when the portable stage 10 is in its transport configuration. Furthermore, preferably, one of the stabilizer beams in the pair of stabilizer beams is designed to fold over the other stabilizer beam. Safety cables (not shown), which are attached to the chassis 22 in a conventional manner, are preferably used to ensure that the pairs of stabilizer beams remain folded under the main floor panel 102 during transport of the portable stage 10 .
FIGS. 1E and 2A illustrate a pair of stabilizer beams (e.g., first and second stabilizer beams 202 , 204 ) which are folded under main floor panel 102 . When deploying the first and second stabilizer beams 202 , 204 , the safety cable (not shown) is disconnected and the first and second stabilizer beams 202 , 204 are pivoted so that they are perpendicular to first side 112 of main floor panel 102 . FIG. 2B illustrates first and second stabilizer beams 202 , 204 in their deployed configuration. Preferably, each of the stabilizer beams 202 - 216 have a corresponding gas strut 222 A- 222 H connected between each of the stabilizer beams 202 - 216 and the chassis 22 to assist in positioning the stabilizer beams 202 - 216 at a 90 degree angle relative to the first side 112 or second side 114 of the main floor panel 102 . Gas strut 222 A is shown in FIG. 2 C.
As shown in FIG. 2D, the stabilizer jack 220 A of first stabilizer beam 202 includes a pad 224 A with a telescoping leg 226 A. A pin 228 A is used to coarsely adjust the telescoping leg 226 A using a preset number of apertures 230 A in the leg 226 A. When deploying the first stabilizer beam 202 , after the first stabilizer beam 202 has been positioned, the pin 228 A is removed from the first stabilizer jack 220 A. The pad 224 A is then placed as close to the ground as possible and the pin 228 A is replaced in one of a preset number of apertures 230 A in the leg 226 A. A handle 232 A, which used to finely adjust the telescoping leg 226 A, is then rotated until the pad 224 A contacts the ground.
A similar process is repeated for each of the other stabilizer beams 204 - 216 , as will be understood by those skilled in the art. In fact, the preferred configuration of the other stabilizer beams 204 - 216 is similar to that described in connection with FIG. 2 D. Accordingly, for brevity and to avoid confusion, the specifics of each of the other stabilizer beams will not be described herein.
In order to ensure that the portable stage 10 is level, the stabilizer jacks located at the four corners of the portable stage 10 (e.g., first, fourth, fifth and eighth stabilizer jacks 202 , 208 , 210 and 216 ) are raised by their handles first. First and second level bubbles 234 , 236 , preferably located on a fixed portion of the canopy lifting assembly 400 (see FIG. 3 A), may be used to ensure that the floor assembly 100 is level both front-to-back and side-to-side. Third and fourth level bubbles 238 , 240 , which also may be used to ensure that the floor assembly 100 is level, are preferably located on a fixed portion of the canopy lifting assembly 400 near the corner of the main floor panel 102 which is diagonal to the corner shown in FIG. 3 A. Once the stage has been leveled, the handles of the remaining stabilizer jacks are rotated such that they bear part of the load but without causing the floor assembly 100 to become uneven.
FIG. 3A (in addition to illustrating the level bubbles 234 , 236 ) illustrates a first ( 242 A) of four floor panel locking members 242 A- 242 D and illustrates the first floor panel 104 . The first floor panel locking member 242 A shown in FIG. 3A is pivotally connected to a fixed portion of canopy lifting assembly 400 , so that it pivots to an approximately vertical position once it is detached from the first floor panel 104 . A bolt is fixed to the side of first floor panel 104 and a nut is used to fix the panel locking member 242 A to the panel 104 so that the first floor panel 104 is held in a vertical configuration during transport. Similar components are used for the second, third and fourth floor panels 106 , 108 , 110 , as will be understood by those skilled in the art.
FIG. 3A also illustrates a first stabilizing pin 244 A and a first weight distribution foot 246 A. The first stabilizing pin 244 A is designed to be received by aperture 248 A (see FIG. 2D) in first stabilizer beam 202 to assist in stabilizing first floor panel 104 relative to stabilizer beam 202 . First weight distribution foot 246 A distributes some of the weight of the first floor panel 104 onto the first stabilizer beam 202 . First weight distribution foot 246 A also operates as a shim between first floor panel 104 and stabilizer beam 202 . Preferably, first weight distribution foot takes the form of a cylindrically-shaped rubberized material. As will be understood by those skilled in the art, there are similar components for the other stabilizer beams. For brevity and clarity, the components which correspond with the other stabilizer bars will not be discussed.
To illustrate the final steps in deploying the floor assembly 100 of the portable stage 10 , FIG. 3B provides a perspective view of the portable stage 10 when three of the four floor panels are in their deployed configuration.
After all four of the floor panels are placed in their deployed configuration, the present invention provides a mechanism for joining floor panels on the same side of the main floor panel 102 . Specifically, FIG. 3C illustrates a partial perspective view of the first and second floor panels 104 , 106 , wherein first floor panel joiner bar 250 A is attached to second floor panel 106 . FIG. 3D is a view similar to that of FIG. 3 C and illustrates a partial perspective view of the first and second floor panels 104 , 106 , wherein the first floor panel joiner bar 250 A is used to join the first and second floor panels 104 , 106 . A second floor panel joiner bar 250 B (not shown) is similarly used to join third and fourth floor panels 108 , 110 .
FIG. 3E illustrates a perspective view of the portable stage 10 with the floor assembly 100 deployed and the canopy assembly 300 in its transport configuration. The manner of deploying the canopy assembly 300 will be discussed starting with reference to FIG. 3 E.
The canopy assembly 300 includes a main canopy panel 302 , a first canopy panel 304 and a second canopy panel 306 . The first and second canopy panels 304 , 306 are deployed in a series of steps and then the canopy assembly 300 is lifted to its fully-deployed position.
In order to deploy the first and second canopy panels 304 , 306 , the canopy assembly 300 is raised off of the main floor panel 102 , while the first and second canopy panels 304 , 306 otherwise remain in their transport configuration. The purpose of raising the canopy assembly 300 off of the main floor panel 102 is to provide clearance from the main floor panel 102 so that the first and second canopy panels 304 , 306 may be rotated from their transport configuration to their deployed configuration. The first canopy panel 304 is rotated about first canopy pivot shaft 308 (see also FIG. 3 A), while second canopy panel 306 is rotated about second canopy pivot shaft 310 .
To raise the canopy assembly 300 off of the main floor panel 102 , winch handle 403 is rotated a sufficient number of times to permit rotation of the first and second canopy panels 304 , 306 about their respective canopy pivot shafts 308 , 310 without obstruction by the main floor panel 102 .
The main canopy panel 302 has first through eighth canopy panel securement plates 312 A- 312 H attached to (preferably, integral with) it. Each of the canopy panel securement plates 312 A- 312 H has a corresponding securement plate deployment aperture 314 A- 314 H (see securement plate deployment aperture 314 B for second canopy panel securement plate 312 B in FIG. 4 C). Further, each of the canopy panel securement plates 312 A- 312 H has a corresponding latch pin 313 A- 313 H hanging from it by a corresponding latch pin chain 315 A- 315 H. The securement plate deployment apertures 314 A- 314 H, in combination with the latch pins 313 A- 313 H, are used to hold first and second canopy panels 304 , 306 in a deployed position. Preferably, second, third, sixth and seventh canopy panel securement plates 312 B, 312 C, 312 E, 312 F correspondingly have first, second, third and fourth spring-pin receiving apertures 316 , 318 , 320 , 322 , which are used to hold first and second canopy panels 304 , 306 in their transport configuration. FIG. 4B (with reference to FIG. 4C) shows spring-pin receiving aperture 316 being used to hold first canopy panel 304 in its transport configuration.
Referring now to FIGS. 3E and 4A, first canopy panel 304 includes first and second spring-pin assemblies 324 , 326 (only spring-pin assembly 324 is shown in FIG. 4 A), while second canopy panel 306 includes third and fourth spring-pin assemblies 328 , 330 . First through fourth spring-pin assemblies 324 , 326 , 328 , 330 each includes corresponding first through fourth spring pins 332 , 334 , 336 , 338 , which are biased so that they are extended (spring pin 332 is shown in FIG. 4 D). A first spring-pin release wire 340 extends between the first spring-pin assembly 324 and the second spring-pin assembly 326 (see FIGS. 3 E and 4 A), and is used to retract first and second spring pins 332 , 334 . Similarly, a second spring-pin release wire 342 extends between the third spring-pin assembly 328 and the fourth spring-pin assembly 330 , and is used to retract the third and fourth spring pins 336 , 338 . As will be understood by those skilled in the art, first and second spring-pin release wires 340 , 342 are exaggerated in length in FIG. 3E (i.e., they are drooping) so that they may be more easily seen.
First through fourth spring-pin assemblies 324 , 326 , 328 , 330 are aligned so that their respective spring pins 332 , 334 , 336 , 338 are correspondingly aligned with first through fourth spring-pin receiving apertures 316 , 318 , 320 , 322 when the first and second canopy panels 304 , 306 are in their transport configuration. Accordingly, the spring pins and corresponding apertures hold the first and second canopy panels 304 , 306 in place.
When deploying the first and second canopy panels 304 , 306 , spring pins are used to assist a user in getting the first and second canopy panels 304 , 306 into a semi-deployed configuration (see FIG. 4 D). It should be noted that each canopy panel is separately placed into its semi-deployed configuration.
Specifically, with respect to first canopy panel 304 , a user pulls the first spring-pin release wire 340 thereby respectively retracting first and second spring pins 332 , 334 from first and second spring-pin receiving apertures 316 , 318 . A force is then exerted by the user in an outward and upward direction, causing first canopy panel 304 to rotate about first canopy pivot shaft 308 . While the first canopy panel 304 is being rotated, the first spring-pin release wire 340 is released by the user, causing the first and second spring pins to respectively extend (or abut) against second and third canopy panel securement plates 312 B, 312 C (see, e.g., FIG. 4 C). The first canopy panel 304 is rotated until first and second spring pins 332 , 334 are respectively advanced past outer edges 344 , 346 of second and third canopy panel securement plates 312 B, 312 C. When this occurs, first and second spring pins 332 , 334 become fully-extended. Subsequently, the first canopy panel 304 is released and the first canopy panel 304 remains in a semi-deployed configuration (shown in FIG. 4D) due to first and second spring pins 332 , 334 engaging outer edges 344 , 346 of second and third canopy panel securement plates 312 B, 312 C. A similar procedure is followed to semi-deploy the second canopy panel 306 , as will be understood by those skilled in the art.
To fully-deploy the first canopy panel 304 , first canopy panel 304 includes first through fourth canopy panel deployment apertures 348 A- 348 D (second canopy deployment aperture 348 B is shown in FIG. 4 C), which correspond with first through fourth securement plate deployment apertures 314 A- 314 D. Similarly, to fully-deploy the second canopy panel 306 , second canopy panel 306 includes fifth through eighth canopy panel deployment apertures 348 E- 348 H, which correspond with fifth through eighth securement plate deployment apertures 314 E- 314 H.
With reference to the first canopy panel 304 , a user simply lifts the first canopy panel 304 to its fully-deployed position and respectively inserts latch pins 313 A- 313 D into both canopy deployment apertures 348 A- 348 D and securement plate deployment apertures 314 A- 314 D (see FIG. 4 E). Advantageously, the first and second spring pins 332 , 334 do not prevent the first canopy panel 304 from being extended to its fully-deployed position, but does prevent it from dropping below its semi-deployed position without pulling the first spring-pin release wire 340 . Furthermore, the above-described technique allows a single individual to fully-deploy the canopy panels.
Now the canopy lifting mechanism 400 will be described. FIG. 5A illustrates a perspective view of the canopy lifting mechanism 400 of the portable stage 10 , with the flooring, stabilizer beams and chassis removed for ease of understanding. Similarly, FIG. 5B is a top view of the canopy lifting mechanism 400 of the portable stage 100 , with the flooring, stabilizer beams and chassis removed for ease of understanding.
With reference to FIGS. 5A and 5B, the components of the canopy lifting mechanism 400 include a winch 402 having a handle 403 ; first, second, third and fourth sleeve members 404 A- 404 D; first, second, third and fourth extension beams 406 A- 406 D; first, second, third and fourth stanchions 408 A- 408 D (second stanchion 408 B is shown more clearly in FIG. 5 C); first, second, third an fourth stanchion pulleys 410 A- 410 D (second stanchion pulley 410 B is shown more clearly in FIG. 5 C); a bell crank assembly 412 ; first and second pulley mount assemblies 414 A, 414 B; winch cable 416 (shown in red in FIG. 5 B); first extension beam cable 418 A (shown in blue in FIG. 5 B); second extension beam cable 418 B (shown in green in FIG. 5 B); third extension beam cable 418 C (shown in aqua in FIG. 5 B); and fourth extension beam cable 418 D (shown in magenta in FIG. 5 B). In addition, the canopy lifting mechanism 400 includes first sleeve pulley 420 A, second sleeve pulley 420 B (shown in FIG. 5 C), third sleeve pulley 420 C and fourth sleeve pulley 420 D.
With reference to FIGS. 5A and 5B, first, second, third and fourth sleeves 404 A- 404 D are attached to chassis 22 via attachment members 422 , which are attached to sleeves (preferably by welding) or are integral with the sleeves. Among other things, screws and bolts may be used to attached attachment members 422 to chassis 22 .
First, second, third and fourth extension beams 406 A- 406 D are sized to be received within first, second, third and fourth sleeves 404 A- 404 D, respectively. Furthermore, first, second, third and fourth extension beams 406 A- 406 D are connected to main canopy panel 302 . Among other things, screws and bolts may be used to attach extension beams 406 A- 406 D to the main canopy panel 302 .
Accordingly, the first, second, third and fourth sleeves 404 A- 404 D are all fixed relative to the chassis 22 (and hence relative to main floor panel 102 ). Similarly, the first, second, third and fourth extension beams 406 A- 406 D are all fixed relative to the main canopy panel 302 . Since first, second, third and fourth extension beams 406 A- 406 D lie within the first, second, third and fourth sleeve members 404 A- 404 D, as extension beams 406 A- 406 D are raised within the sleeve members 404 A- 404 D, the main canopy panel 302 is lifted relative to the main floor panel 102 .
FIG. 5D illustrates a partial perspective view of one of the extension beams (e.g., second extension beam 406 B) of the canopy lifting mechanism 400 of the portable stage. As shown in FIG. 5D, the second extension beam 406 B is a generally rectangular hollow tube. Furthermore, the second extension beam 406 B has a first end 430 B (which extends out of sleeve 404 B in FIG. 5A) and a second end 432 B (shown in FIG. 5 D). The first end 430 B of the second extension beam 406 B extends from the second sleeve 404 B when inserted therein and is connected to the main canopy panel 302 . The second end 432 B of the second extension beam 406 B is inserted into second sleeve 404 B and has a protrusion 434 B that extends therefrom. Protrusion 434 B is where second extension beam cable 418 B is attached. As will be described in further detail below, the second extension beam cable 418 B runs along the inside of a first corner 490 B of second extension beam 406 B (along the outside of the second stanchion 408 B, which is not shown in FIG. 5 D), around the second stanchion pulley 410 B (not shown in FIG. 5D) and along the second corner 492 B of second extension beam 406 B. Ultimately, second extension beam cable 418 B connects with protrusion 434 B.
FIG. 5C illustrates a cutaway view of a sleeve and extension beam (e.g., second sleeve 404 B and second extension beam 406 B) of the present invention with a stanchion (e.g., second stanchion 408 B) located within both the sleeve and the extension beam. FIG. 5C illustrates the cooperation of the second sleeve 404 B (shown in black), second extension beam 406 B (shown in green), second stanchion 408 B (shown in blue), second stanchion pulley 410 B (shown in blue), second sleeve pulley 420 B (shown in black) and second extension beam cable 418 B (shown in red).
Preferably, second stanchion 408 B is a generally cylindrical hollow tube. Furthermore, the second stanchion 408 B has a first end 438 B and a second end 439 B. The first end 438 B of the stanchion 408 B has stanchion pulley 410 B attached thereto, while second end 439 B of the stanchion 408 B is attached to second sleeve 404 B. More specifically, second end 439 B of the stanchion 408 B is inserted into second extension beam 406 B (which has been inserted into second sleeve 404 B). The second end 439 B of the stanchion 408 B is then attached to second sleeve 404 B, preferably by screws and bolts. Importantly, the bolts used to attach the second stanchion 408 B to the second sleeve 404 B limit the downward travel of the second extension beam 406 B, which lies in between second sleeve 404 B and second stanchion 408 B.
With reference to FIGS. 5C and 5D, the second extension beam cable 418 B enters the second sleeve 404 B via an opening (not shown) and runs around second sleeve pulley 420 B, which directs second extension beam cable 418 B towards first corner 490 B. The second extension beam cable 418 B runs along first corner 490 B (i.e., from the second end 439 B of the stanchion 408 B to the first end 438 B of the stanchion 408 B) between stanchion 408 B and extension beam 406 B. At the first end 438 B of stanchion 408 B, the second extension beam cable 418 B is threaded through pulley 410 B, which directs second extension beam cable 418 B to the second corner 492 B (i.e., opposite corner) of the second extension beam 406 B (see also FIG. 5 B). The second extension beam cable 418 B then runs from first end 438 B of the stanchion 408 B down to the second end 439 B of stanchion 408 B, along second corner 492 B, between stanchion 408 B and extension beam 406 B. The second extension beam cable 418 B is then attached to protrusion 434 B at the second end 432 B of extension beam 406 B. Accordingly, when a force is exerted which pulls the second extension beam cable 418 B through the opening near the bottom of the sleeve 404 B, the second extension beam 406 B is forced upward. The remaining sleeve members and their associated components operate similarly and, therefore, will not be described.
Reference is now made to FIG. 5E, which is a top view (similar to FIG. 5B) illustrating the preferred position of bell crank assembly 412 relative to chassis 22 . Specifically, the bell crank assembly 412 is shown to be pivotally mounted to the underside of chassis 22 .
The present invention allows for the canopy to be tilted relative to the main floor panel for acoustical, lighting and drainage purposes (among other things). Specifically, the front end of the canopy (e.g., first canopy panel 304 ) is raised to a height above the main floor panel 102 which is greater than the back end of the canopy (e.g., second canopy panel 306 ). Reference is made to FIGS. 5A-5H and FIGS. 6A-6C to show the various components of the canopy lifting mechanism 400 and to show how the canopy assembly 300 is tilted using a single winch 402 .
FIG. 5F is a perspective view of bell crank assembly 412 . With reference to FIGS. 5B and 5F, bell crank assembly 412 is preferably pivotally attached to underside of chassis 22 at bell crank pivot 450 . The bell crank assembly 412 has a first end 452 and a second end 454 . Importantly, the distance D 1 from bell crank pivot 450 to first end 452 is longer than the distance D 2 from bell crank pivot 450 to second end 454 . The difference between D 1 and D 2 allows the canopy assembly 300 to be tilted when raised using a single winch 402 .
Winch 402 has winch cable 416 that extends around a pulley 450 at first end 452 of bell crank assembly 412 and then anchors back on the frame of the winch 402 . This effectively creates what is known as a two-part line. First and second extension beam cables 418 A, 418 B run around pulleys in pulley block 414 A and around pulleys 456 at first end 452 of bell crank assembly 412 , and are anchored at pulley block 414 A. Similarly, third and fourth extension beam cables 418 C, 418 D run around pulleys in pulley block 414 B and around pulleys 458 at second end 454 of bell crank assembly 412 , and are anchored at pulley block 414 B.
When one turns the winch 402 by winch handle 403 , the winch 402 takes up the winch cable 416 causing the bell crank assembly 412 to pivot about bell crank pivot 450 as the first end 452 of the bell crank assembly 412 moves towards winch 402 . Since the bell crank pivot 450 is not centered between the first and second ends 452 , 454 of the bell crank assembly 412 , the first end 452 of the bell crank assembly 412 will move a greater distance than second end 454 of bell crank assembly 412 . Accordingly, first and second extension beams 406 A, 406 B (i.e., the beams for the front end of canopy) will be raised higher than third and fourth extension beams 406 C, 406 D (i.e., the beams for the back end of the canopy), since proportionately more cable will be drawn by the first end 452 of the bell crank assembly 412 relative to the second end 454 of the bell crank assembly 412 .
As will be understood by those skilled in the art, the connection between the extension beams and the main canopy panel must be a pivoted connection, since the front end is raised higher than the back end. An accommodation must also be made for the variation in distance between the first end 430 A of first extension beam 406 A and the first end 430 D of fourth extension beam 406 D. Likewise, an accommodation must also be made for the variation in distance between the first end 430 B of the second extension beam 406 B and the first end 430 C of the third extension beam 406 C.
FIGS. 6A-6C illustrate a floating pivot 900 A, which accommodates the variations in distance between the first end 430 B of the second extension beam 406 B and the first end 430 C of the third extension beam 406 C. (There is a similar floating pivot 900 B, which accommodates the variations in distance between the first end 430 A of the first extension beam 406 A and the first end 430 D of the fourth extension beam 406 D.) Specifically, FIG. 6A illustrates a perspective view of the floating pivot 900 A, wherein floating pivot 900 A is pivotally attached to third extension beam 406 C. (Similarly, a floating pivot 900 B is pivotally attached to fourth extension beam 406 D.) FIG. 6B is a phantom view similar to FIG. 6 A. FIG. 6C is a phantom view similar to FIG. 6B, which illustrates two possible positions of the floating pivot 900 A.
In addition to being pivotally attached to third extension beam 406 C, the floating pivot 900 A is attached to main canopy panel 302 . Accordingly, when main canopy panel 302 is tilted relative to main floor panel 102 , floating pivot 900 A pivots about its pivotal connection to third extension beam 406 C as will be understood from viewing FIG. 6 C. Similarly, when main canopy panel 302 is tilted relative to main floor panel 102 , floating pivot 900 B pivots about its pivotal connection to fourth extension beam 406 D.
As will be understood by those skilled in the art, a two-part line allows the effective length of travel of the first and second ends 452 , 454 of the bell crank assembly 412 to be doubled with respect to linear cable take up at the extension beams 406 A- 406 D.
It should be noted that small nylon tabs (not shown) may be placed on the inside walls of the sleeve near its first end and on the outside walls of the extension beam near its second end. The nylon tabs act as a bearing surface to prevent metal-to-metal contact between the tubes.
Although such components are well known, FIG. 5G is provided to illustrate a perspective view of winch 402 and FIG. 5H is provided to illustrate a perspective view of pulley mount 414 A, 414 B. Once the portable stage has been fully-deployed, it may look similar to the illustration shown in FIGS. 7 and 8.
It should be understood that modifications may be made to the invention without departing from the spirit of the invention. Specifically, among other things, the invention is not intended to be limited to a portable stage with four hinged floor panels, two rotatable canopy panels, eight pivotal stabilizer beams and four pivotal locking members. Instead, more or less floor panels, canopy panels, stabilizer beams and locking members may be used without departing from the scope of the invention. In addition, variations to these or other components may be made without departing from the scope of the invention.
While an effort has been made to describe some alternatives to the preferred embodiment, other alternatives will readily come to mind to those skilled in the art. Therefore, it should be understood that the invention may be embodied in other specific forms without departing from the spirit or central characteristics thereof. The present examples and embodiments, therefore, are to be considered in all respects as illustrative and not restrictive, and the invention is not intended to be limited to the details given herein.
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A portable stage having at least a transport configuration and a deployed configuration is disclosed. The portable stage includes a chassis having wheels rotatably attached thereto and a main floor panel attached to the chassis. First and second deployable floor panels are pivotally attached to the main floor panel, and a deployable canopy is attached to the chassis. The deployable canopy is stored between the first and second floor panels when the portable stage is in its transport configuration. When the stage is deployed, the main floor panel, first floor panel and second floor panel form a main stage, and the canopy is large enough to cover the main stage.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to an earphone comprising a case that houses an electroacoustic transducer, the case being adapted to be put in the hollow or concha of the flap of an ear known as an auricle.
2. Description of the Prior Art
One earlier earphone has a sound outlet to be inserted into the external auditory meatus of an ear in use. Modern earphones have a case housing an electrostatic transducer, the case being shaped so that it is simply put in the concha of an ear flap or auricle. The case is not inserted into the external auditory meatus of an ear, and hence does not make the user feel uncomfortable. Furthermore, the electroacoustic transducer housed in the case may be of a large size for improved sound quality particularly in a low frequency range. For these reasons, the modern earphone design has gained almost exclusive popularity among earphone users.
One recent earphone disclosed in Japanese Patent Publication No. 64-4398 comprises a housing having an external ear engaging region on the outer periphery of a front portion of the housing, the external ear engaging region being of a circular shape whose diameter is larger than the remainder of the housing. In use, the external ear engaging region is placed in the cavity or hollow of an external ear of the user.
However, if the housing were increased in size to accommodate an electroacoustic transducer of larger size for improved acoustic characteristics, then when the earphone is placed in the cavity of the external ear, it would impose pressure on a dimensionally small ear region between the tragus and an upper portion of the inlet of the external auditory meatus which is contiguous to the antitragus. Therefore, the size of the housing and hence the earphone itself is governed by the dimension between the tragus and the upper portion of the inlet of the external auditory meatus which is contiguous to the antitragus.
SUMMARY OF THE INVENTION
In view of the aforesaid problems, it is an object of the present invention to provide an earphone to be placed in the hollow or concha of an auricle, the earphone incorporating an electroacoustic transducer that is as large in diameter as possible for improved acoustic characteristics without imposing pressure on the user's ear.
According to the present invention, there is provided an earphone for use in the concha of the auricle of an ear having a tragus and an antitragus with an intertragus recess defined therebetween, and an external auditory meatus. The earphone comprises a case of a substantially elliptical shape having a major axis and a minor axis, the case being adapted to be supported between the tragus and the antitragus when placed in the concha. An electroacoustic transducer is housed in the case, and a leadout portion extends from the case to support a cord. The leadout portion has a diameter smaller than the major and minor axes of the case. The case and the leadout portion are shaped such that when the leadout portion is positioned in the inter-tragus recess, the minor axis of the case is aligned with a line segment interconnecting the antitragus and an upper edge of the inlet of the external auditory meatus of the ear above the tragus, and the major axis of the case is aligned with a line segment interconnecting the tragus and a wall portion of the concha opposite the tragus.
When the case of the earphone is put in the concha, the leadout portion is placed between and supported by the tragus and the antitragus, and the major axis of the case is oriented from the tragus and the wall portion of the concha opposite the tragus.
The above and other objects, features, and advantages of the present invention will become apparent from the following description when taken in conjunction with the accompanying drawings which illustrate a preferred embodiment of the present invention by way of example.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 is a perspective view of an earphone assembly according to the present invention;
FIG. 2 is a view showing the manner the earphone assembly shown in FIG. 1 is used with ears;
FIG. 3 is an enlarged exploded cross-sectional view of an earphone of the earphone assembly shown in FIG. 1;
FIG. 4 is a front elevational view of a frame of an electroacoustic transducer of the earphone; and
FIG. 5 is a rear elevational view of a front case member of the earphone.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
As shown in FIG. 1, an earphone assembly has a lefthand earphone 1a, a righthand earphone 1b, a plug 2 to be connected to a reproducing device such as a tape recorder or the like, and a remote control unit 5 connected to the earphones 1a, 1b by respective cords 4 and to the plug 2 by a cord 3. When in use, the earphones 1a, 1b are placed respectively in the cavities or conchae 9 (see FIG. 2) of lefthand and righthand ear flaps or auricles 6a, 6b.
As shown in FIG. 1, each of the earphones 1a, 1b has a case 7 and a leadout portion 8 extending from the case 7. The case 7 is of a substantially elliptical shape having a major axis A having a size La that is the longer of the two axes with respect to which an ellipse is symmetric and a minor axis B having a size Lb that is the smaller of the two axes with respect to which an ellipse is symmetric. The leadout portion 8 is of an elongated shape whose diameter is much smaller than the major and minor axes A, B of the case 7. The leadout portion 8 has a longitudinal axis C that is inclined at an angle α with respect to the major axis A of the case 7. The angular displacement α of the axis C from the major axis A on the lefthand earphone 1a is opposite to that on the righthand earphone 1b such that the lefthand and righthand earphones 1a, 1b are symmetrical in shape as shown in FIG. 1. The angle α is selected on the basis of the configuration of the lefthand and righthand auricles 6a, 6b, and is in the range of from 40 to 60 degrees, preferably about 50 degrees.
As shown in FIG. 1, the lefthand and righthand auricles 6a, 6b are substantially symmetrical in shape, and each have a hollow or concha 9, a tragus 10, an antitragus 11, a recess 12 between the tragus 10 and the antitragus 11, i.e., an inter-tragus recess, and an external auditory meatus 13 disposed behind the tragus 10 and extending from the concha 9 into the head.
When each earphone is used, as shown in FIG. 1, the case 7 thereof is placed on the concha 9 and supported between the tragus 10 and the antitragus 11, with the leadout portion 8 positioned in and extending along the intertragus recess 12. The antitragus 11 is spaced by a distance L1 from an upper edge 14 of the inlet of the external auditory meatus 13 above the tragus 10, and the tragus 10 is spaced by a distance L2 from a wall portion 9a of the concha 9 opposite the tragus 10. The distance L2 is larger than the distance L1. The angle α (FIG. 1) of the axis C with respect to the major axis A is determined depending on the difference between the dimensions L1, L2. More specifically, the case 7 and the leadout portion 8 are shaped such that when the leadout portion 8 is positioned in the inter-tragus recess 12, the minor axis B extends between, i.e., aligns with a line segment interconnecting, the antitragus 11 and the upper edge 14, and the major axis A extends between, i.e., aligns with a line segment interconnecting, the tragus 10 and the wall portion 9a.
FIG. 3 shows the case 7 in exploded cross section. The case 7 comprises a case body 15 from which the leadout portion 8 extends, a front case member 16, and an electroacoustic transducer 17 interposed between the case body 15 and the front case member 16. The front face of the front case member 16 is covered with a protective net 18. The case body 15 and the front case member 16 have an elliptical outer shape. The electroacoustic transducer 17 includes a frame 17a which has a circular outer circumferential shape, as shown in FIG. 4.
The frame 17a has on its outer circumferential edge a pair of radially outward engaging teeth 19 with a recess 20 defined therebetween, and a pair of radially outward engaging teeth 21 with a lead wire slot 22 defined therebetween, the engaging teeth 21 being substantially diametrically opposite to the engaging teeth 19.
As shown in FIG. 5, the front case member 16 has on its outer circumferential edge a recess 23 for receiving the engaging teeth 19, an engaging rib 24 disposed centrally in the recess 23 for engaging in the recess 20, and a recess 25 diametrically opposite to the recess 23 for receiving the engaging teeth 21. The front case member 16 also has a plurality of circumferentially spaced holes 26 for radiating sound therethrough from the electroacoustic transducer 17.
As shown in FIG. 4, the engaging teeth 19 and the engaging teeth 21 are diametrically spaced from each other along the major axis A of the case 7. Consequently, the dimension of the case 7 along the minor axis B thereof can be reduced substantially to the diameter of the frame 17a of the electroacoustic transducer 17.
The case 7 of the above dimensions does not impose excessive pressure on the user's ear when placed in the concha 9, so that the user does not feel uncomfortable in the use of the earphone. Since the diameter of the frame 17a of the electroacoustic transducer 17 may be substantially the same as the dimension of the case 7 along the minor axis B thereof, the size of the electroacoustic transducer 17 may be as large as possible within the case 7. Accordingly, the earphone according to the present invention provides good acoustic characteristics.
Although a certain preferred embodiment of the present invention has been shown and described in detail, it should be understood that various changes and modifications may be made therein without departing from the scope of the appended claims.
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An earphone has a case housing an electroacoustic transducer, the case being adapted to be put in the concha of the auricle of an ear. The case is of an elliptical shape so that it can snugly fit in the concha without under pressure imposed on the ear.
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BACKGROUND OF THE INVENTION
The present invention relates to measurement of the blood pressure of a patient.
The invention relates particularly to a procedure which is based on the method of Riva-Rocci/Korotkoff, and in which the patient himself secures an inflatable pressure cuff in place and switches a switch into a first switch position to automatically close a valve, subsequent opening of the valve after the cuff has been inflated permitting the air in the cuff to slowly escape. Simultaneously a battery-fed current supply circuit is switched on, two indicators of a dual indicator manometer, which are blocked when the current supply circuit is switched off, are released by exciting respective electromagnets, and an electronic barrier is switched on to prevent blocking of the indicators. Thereafter the patient pumps the cuff to a pressure which lies above his systolic blood pressure and switches the switch into a second switch position to open the valve, and an electrical device detects the start or stop, respectively, of the Korotkoff noise and blocks, at the respective start or stop, one of the indicators of the manometer. Blocking is effected by interrupting the circuit for one of the electromagnets. The electrical device also switches off the electrical circuit after both indicators have been blocked.
The present invention is based on a blood pressure measuring method in which the inflatable blood pressure cuff initially exerts, on an artery, a pressure above the patient's systolic pressure value, the cuff pressure is then gradually reduced and electrical signals are derived from the resulting Korotkoff sounds, a first indicator of a dual-indicator manometer which is influenced by the cuff pressure is blocked at the commencement of such signals, which occurs at the systolic pressure value, and the second indicator of the manometer is blocked upon termination of such signals, this occurring at the diastolic pressure value.
A sphygmomanometer which has a separate automatic indication for the systolic and diastolic pressure values is disclosed in German Offenlegungsschrift [Laid-open Application] No. DT-OS 22 09 633, which gives no precise information about the circuitry of the sphygmomanometer. Moreover, this sphygmomanometer has a relatively high current consumption and that publication provides no indication as to how this current consumption could be reduced.
Furthermore, U.S. Pat. No. 3,056,401 discloses a self-recording sphygmomanometer which has substantially the same drawbacks, although in this device no current is consumed when the indicators of the dual indicator manometer are blocked.
SUMMARY OF THE INVENTION
It is an object of the present invention to simplify the procedure required to obtain a blood pressure measurement.
Another object of the invention is to provide a simple apparatus and procedure which can be utilized by the subject himself.
A further object of the invention is to reduce the electrical power consumed by such apparatus.
These and other objects according to the invention are achieved by placing the cuff in position, moving a two-position switch into a pumping position which prevents deflation of the cuff and unblocks the manometer indicators, pumping the cuff to a pressure above the systolic pressure of the subject, and moving the switch into a measuring position which allows the pressure in the cuff to gradually decrease, one indicator to be blocked at the onset of Korotkoff sound signals, and the other indicator to be blocked at termination of the Korotkoff sound signals.
The system further includes an electrical power supply source which is connected when the switch is moved to its pumping position and disconnected after the switch has been moved to its measuring position and both indicators have become locked.
In accordance with a further feature of the invention, the apparatus is provided with a function indicator device including an indicator element which is switched on in the pumping position of the switch, remains on in the measuring position, and is switched off by the automatic switching off of the current supply circuit. Switching on of the indicator element indicates to the patient that he may begin to pump up the cuff and switching off of the indicator element indicates that the measurement is completed and the patient may remove the cuff.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a block circuit diagram of one preferred embodiment of the invention.
FIGS. 2 and 3 are circuit diagrams of exemplary embodiments of several of the units of the embodiment of FIG. 1.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
In the system shown in FIG. 1, an inflatable pressure cuff 1 contains a microphone 2 which is preferably a body sound microphone. The body sound microphone is connected to a series-connected circuit path including a preamplifier 3, a bandpass filter 4 which essentially permits only the frequencies of the Korotkoff sound to pass, a postamplifier 5, a rectifier circuit 6, a threshold value circuit 7 and a monostable multivibrator 8. Three lines 10, 11 and 12 branch off from an output line 9 of the monostable multivibrator 8, the first line 10 being connected with a first input of a function indicator circuit 13, the second line 11 being connected with a first input 14 of a first control device 15 and the third line 12 being connected with a first input 16 of a second control device 17.
Control device 15 has a first output 18 connected to a second input of the function indicator circuit 13, a second output 19 connected to a second input 20 of the second control device 17, and a third output 21 connected to a first input 22 of a dual-indicator manometer 23. The second input 24 of manometer 23 is connected to a first output 25 of the second control device 17.
A second output 26 of the second control device 17 is connected to the input of a switch-off device 27 to automatically switch off the current supply circuit. The output of the switch-off device 27 is connected to a first input 28 of an electronic switch-on memory 29 which has three inputs 28, 30 and 31. The second input 30 of memory 29 is connected to a direct voltage source 32, preferably a battery, and the third input 31 is connected to a switch 33. Switch 33 has two switching positions, a measuring position m and a pumping position p.
The switch-on memory 29 has a first output 34 connected in parallel with a delaying device 35 and to a second input 36 of the first control device 15, and a second output 37 connected to a stabilization circuit 38 provided for stabilizing the voltage from direct voltage source 32. A stabilized direct voltage U stab is available at an output 39 of the stabilization circuit to supply the system with operating current.
A squeeze bulb 40 provided to pump up cuff 1 is in communication, via air hoses 41, firstly with cuff 1, secondly with the dual-indicator manometer 23, and thirdly with a valve 42 which is mechanically coupled to switch 33. Bulb 40 is provided with a manually actuatable outlet valve 43 to enable air to be completely exhausted from the cuff after a blood pressure measurement.
The above-described device operates as follows: If a patient intends to measure his own blood pressure, he initially applies the pressure cuff 1, which is preferably of a type that can be secured in place with but one hand, taking care that the body sound microphone contained in the pressure cuff is placed approximately above one of the patient's arteries.
Thereupon the patient switches switch 33, which is preferably a rocker switch, into the pumping position p. This closes valve 42. At the same time, switch 33 supplies a signal to the third input 31 of the switch-on memory 29, which stores the switching state of switch 33 in the manner of a bistable flip circuit. This automatically switches on the current supply for the entire system, which current supply is composed of the direct voltage source 32 and the stabilizing circuit 38.
Simultaneously, the indicators of the dual-indicator manometer 23, which were blocked in the starting state, are released to return to the zero position of the manometer. More specifically, to release the indicators, switching on of the current supply excites an electromagnet which is associated with each indicator, each indicator being in the blocked state when no current is being supplied to its respective electromagnet.
Switching on of the current supply also actuates the function indicator circuit 13 and illuminates a light source belonging to this circuit. For reasons of energy savings this light source is preferably a light emitting diode. Lighting up of the light source signals that the cuff can now be pumped up by acting on the bulb 40. Since the indicators of the dual-indicator manometer 23 have been released, the manometer now indicates the pressure in the cuff, which increases with the pumping action.
Noises resulting from the pumping process, which are picked up by microphone 2 and which, after being filtered through bandpass filter 4, could erroneously be identified as Korotkoff sounds, are prevented from blocking the indicators during the pumping process by an electronic block. This electronic block is produced by a blocking signal emitted at the first output 34 of switch-on memory 29 fed to the second input 36 of the first control device 15, this signal also being fed via the second output 19 of device 15 to the second input 20 of the second control device 17. This signal blocks the first and second control devices 15 and 17 so as to prevent them from exciting the manometer electromagnets.
Once the patient has pumped the cuff to a pressure value which lies above his average systolic pressure, he switches switch 33 into the measuring position m so that an automatic measuring process is initiated to measure the systolic and diastolic blood pressures.
In detail, the following takes place: Valve 42 is opened upon switching of switch 33 to position m so that the air contained in the cuff can gradually escape. The pressure reduction in the cuff takes place at a speed of, for example, 5 Torr/s. Simultaneously with switching of switch 33, the above-described electronic block, which during pumping of the cuff prevented blockage of the indicators, is released.
For a certain period of, for example, 1 s, however, another block will still be effective under control of the delaying device 35. This device is preferably constituted by an RC member acting as the delaying member, whose capacitor has been charged to the potential of the blocking signal while the switch 33 was in position p and discharges with its associated time constant via the associated resistor when switch 33 is switched into position m. The blocking signal, for example, consists of the positive, stabilized direct voltage U stab .
The last-mentioned block has the result that the patient has some time, after switching of switch 33 into the switch position m, to bring the part of his body bearing the cuff into a rest position before the automatic measurement begins.
During the subsequent descent of the cuff pressure, a point is reached at which the previously stopped blood in the artery begins to flow. At this time pulsed Korotkoff sounds appear and are picked up by microphone 2 and converted into electrical oscillations. The oscillations are amplified by preamplifier 3 and, after passing through bandpass filter 4, which permits only the frequencies between 40 and 140 Hz which are characteristic for the Korotkoff sound, to pass, the oscillations are amplified further in postamplifier 5 and rectified by means of rectifier circuit 6, which is preferably a full wave rectifier. The threshold voltage of threshold value switch 7 is given a value such that only the rectified oscillations of a relatively high amplitude are converted into rectangular pulses, thereby to suppress interference.
The monostable multivibrator 8 is flipped to its quasi-stable state by the leading edge of the first pulse of the rectangular pulses and remains in that state until, for example, 300 ms have expired, at which time it flips back to its stable state. The monostable multivibrator 8 thus emits one rectangular pulse of 300 ms duration for every Korotkoff sound, which pulse acts as a blocking pulse on the function indicator circuit 13 and temporarily interrupts the light from the luminescent diode.
At the same time, the pulses from monostable multivibrator 8 arrive at the first input 14 of the first control device. A bistable flip circuit associated with the first control device takes care that only the leading edge of the first pulse from the monostable multivibrator interrupts the circuit for the electromagnet associated with the first control device 15 so that that indicator of the dual-indicator manometer 23 which is associated with this electromagnet is blocked in its present position. The indicator thus stops at a pressure value which corresponds to the systolic blood pressure.
The leading edge of the first pulse emitted by the monostable multivibrator 8 also arrives at the first input 16 of the second control device 17 to cause the flow of current in the circuit for the second electromagnet associated with the second indicator of the manometer to be halted so that the second indicator is blocked at the same time as the first indicator. The second control device 17, however, is constructed so that it excites the second electromagnet with every pulse from the monostable multivibrator 8 for the duration of that pulse so that the associated second indicator of the manometer 23 sets itself to the instantaneous cuff pressure, which drops somewhat between two successive Korotkoff sounds. Between every two pulses from the monostable multivibrator 8, the second indicator is blocked by interruption of the current flow to its electromagnet.
After the last pulse from the monostable multivibrator 8, or after the last Korotkoff noise, respectively, the second indicator of the manometer indicates the diastolic blood pressure.
Approximately 1.5 to 2 seconds after the last pulse from monostable multivibrator 8, switch-off device 27 automatically emits a switch-off pulse to switch-on memory 29, which pulse causes the current supply for the system to be switched off.
The patient can then open the outlet valve 43, and thus permit all of the air to escape from the cuff, and, finally, can remove the cuff.
The device consumes current only during the measuring process so that the battery 32 is used very sparingly.
If integrated circuits, preferably CMOS circuits, are used for the electronic portion of the apparatus, the current consumption can be kept so low that, with normal use of the system, it can be operated on one battery for more than 6 months.
Output 39 is also connected to components 3 to 8 connected to output 39 to supply their required operating voltage from circuit 38.
Embodiments of units 13, 15 and 17 are shown in FIG. 2. Function indicator circuit 13 comprises two transistors 131 and 132 and a light emitting diode 133. When switch 33 is switched into its pumping position, p, the base of transistor 132 is forward-biased and diode 133 lights up. During a measurement operation, the pulses produced by monostable multivibrator 8 are fed to the transistors 131 and 132 and have the effect of periodically temporarily interrupting the light emission from diode 133.
Control device 15 consists of a first differentiation circuit 151 consisting of elements 151' and 151", a first rectifier 152, a first flip-flop 153, a second differentiation circuit 154 consisting of elements 154' and 154", a second rectifier 155, a first monostable multivibrator 156, first and second electronic switches 157 and 158, and a resistor 159. Switch 157 and resistor 159 are connected to a first solenoid 160 belonging to the manometer 23. When switch 33 is switched into its pump position, p, the positive potential + U triggers the first flip-flop 153 and the resulting output signal from that flip-flop closes switch 158. At the same time, this switching of switch 33 causes the second differentiation circuit 154 to emit a pulse spike which is passed by the second rectifier 155 and triggers the first monostable multivibrator 156 to produce an output pulse that closes switch 157, effectively short circuiting resistor 159 and thus closing an energizing circuit for the first solenoid 160. In this case solenoid 160 releases a normally blocked first pointer of the dual-indicator manometer 23 (see FIG. 1).
The control device 17 consists of a third differentiation circuit 171, consisting of 171' and 171", connected to a third rectifier 172, a second monostable multivibrator 173, third, fourth and fifth electronic switches 174, 175 and 176, and a resistor 177 with, switch 174 and resistor 177 being connected to a second solenoid 178 of manometer 23. The output of flip-flop 153 is connected to 17 thru transistor stage 179.
In the pumping position, p, of switch 33, the output signal of flip-flop 153 is simultaneously supplied to an input of the fifth electronic switch 176 which shunts the fourth electronic switch 175 and closes a circuit for the second solenoid 178. At the same time the output signal of the first monostable multivibrator 156 is supplied to the first electronic switch 174 which closes to effectively short circuit resistor 177 so that a full current can flow for energizing solenoid 178. The solenoid releases the normally blocked second pointer of manometer 23.
At the end of a selected period of time during which the monostable multivibrators 156 and 173 are triggered out of their stable state, the electronic switches 157 and 174 are opened so that only a holding current for the solenoids 160, 178 can flow.
When thereafter switch 33 is switched in its measuring position, m, the monostable multivibrator 8 emits, for each Korotkoff sound, one rectangular pulse which is led to the differentiation circuit 151, rectifier 152 and the first flip-flop 153. With the beginning of the first Korotkoff sound the flip-flop 153 emits an output signal which causes electronic switch 158 to switch to its open condition. In this condition the first pointer of manometer 23 is blocked.
During every rectangular pulse (Korotkoff sound), switch 175 is closed, causing the second solenoid 178 to release the second pointer of manometer 23. Between two consecutive pulses the second pointer is blocked.
FIG. 3 illustrates an embodiment of switch-off device 27 which includes fourth, fifth and sixth transistors 271, 272 and 273 and a diode 274, as well as an embodiment of memory 29 which includes first, second and third transistors 291, 292 and 293. The device 27 is provided with an input 275 and an output 276 which is connected with a control circuit for the second transistor 292. The third transistor 293 which is connected between a positive pole of battery 32 and the stabilization circuit 38 is controlled by a flip-flop constituted by the two transistors 291 and 292.
In their rest, or inactive, state, transistors 291 and 293 are nonconducting. In the pumping position of switch 33, the transistors 291, 292 and 293 are rendered conducting, so that the stabilization circuit 38 (FIG. 1) is conductively connected with the battery 32.
In the measuring position of switch 33, the transistor 293 remains in its conducting state. At the end of an automatic measuring procedure the second control device 17 emits at its output 26 a d.c. voltage of such value that transistor 273 becomes conducting and transistor 272 becomes nonconducting. Only in this last mentioned state do diode 274, which preferably is a Zener diode, and transistor 271 become conducting. At this time output 276 emits a negative potential, -U, to render transistors 291, 292 and 293 nonconducting, thereby disconnecting battery 32 from stabilization circuit 38.
Embodiments of units 35 and 38 are disclosed in the text, Walston and Miller, TRANSISTOR CIRCUIT DESIGN, McGraw-Hill, New York, (1963) at p. 153, FIG. 9.8 (b) and pp. 410-11, FIG. 30.2.
As unit 23 use can be made of the manometer disclosed in, and illustrated in FIG. 4 of, U.S. Pat. No. 3,056,401.
It will be understood that the above description of the present invention is susceptible to various modifications, changes and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims.
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A blood pressure measuring procedure which can be performed by the subject employing a manually inflatable cuff and associated microphone, a measuring circuit responsive to signals having the form of Korotkoff sounds, a dual-indicator manometer having two individually controllable indicators, a control circuit for controlling the operation of the indicators, and a switch switchable between a pumping position in which it permits the cuff to be manually inflated and releases the indicators to respond to the cuff pressure and a measuring position in which the cuff pressure gradually decreases, one indicator is locked in its present position at the onset of Korotkoff sound signals and the other indicator is locked in its present position upon termination of Korotkoff sound signals. The subject places the cuff in position, moves the switch to its pumping position, inflates the cuff to a pressure above his systolic pressure, and then moves the switch to its measuring position.
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TECHNICAL FIELD
This invention relates to sense amplifier (detector) circuits and, more particularly, to insulated gate field effect transistor (IGFET) sense amplifier-detector circuits which have relatively high sensitivity and are useful with random access IGFET memory circuits.
BACKGROUND OF THE INVENTION
U.S. Pat. No. 4,123,799 discloses a latching type IGFET sense amplifier which uses a pair of depletion mode IGFETs to isolate semiconductor memory bit line (input) capacitance from the internal terminals of a cross-coupled pair of IGFETs. One problem with this circuit is that the sensitivity thereof is somewhat limited and, accordingly, its use with today's high density and high speed random access memories is marginal. Another problem with this circuit is that the output terminals and the internal terminals of the cross-coupled pair are common. This limits response time and sensitivity.
It would be desirable to have a relatively high sensitivity latching type of sense amplifier (detector) in which the internal terminals of a cross-coupled pair of the amplifier are isolated from the capacitive loading of the input and output terminals.
SUMMARY OF THE INVENTION
The present invention is a sense amplifier circuit which essentially comprises first and second load elements, first, second, third, and fourth enhancement mode field effect transistors, resistive circuit means, cross-coupled circuit means, latching circuit means, and voltage equalization circuit means. The gates of the first and second transistors serve as circuit input terminals and the output circuitry of each transistor, which is coupled to one of the load elements, serves as a separate circuit output terminal. The cross-coupled circuit means is coupled to the output circuitry of the four transistors, the voltage equalization circuit means, and to the latching circuit means.
In a preferred embodiment, fifth and sixth enhancement mode field effect transistors are used which have the gate terminals thereof coupled together and coupled to the voltage equalization circuit means, and have the output circuitry thereof coupled to the cross-coupled circuit means. In this preferred embodiment, the latching circuit means comprises a seventh enhancement mode field effect transistor, the voltage equalization means comprises an eighth similar transistor, the load elements and the resistive circuit means each comprises a separate depletion mode field effect transistor with the gate coupled to the output circuitry, and the cross-coupled circuit means is a pair of enhancement mode field effect transistors.
The sense amplifier circuit of the present invention isolates the cross-coupled circuit means from input load capacitance at the input terminals and from output load capacitance at the output terminals. This allows the cross-coupled pair to be latched relatively quickly and essentially independent of input and output capacitive loading and thus improves sensitivity and response time of the sense amplifier. In addition, the use of enhancement mode input transistors and depletion mode transistor load elements provides relatively high detection sensitivity and output signal levels which do not suffer from the threshold voltage loss of enhancement mode transistors.
These and other features and advantages of the invention will be better understood from consideration of the following detailed description in conjunction with the accompanying drawing.
BRIEF DESCRIPTION OF THE DRAWING
The FIGURE illustrates a sense amplifier-detector in accordance with the present invention.
DETAILED DESCRIPTION
Referring now to the Figure, there is illustrated a sense amplifier-detector circuit 10 which comprises input transistors T1 and T2, cross-coupled circuitry comprising transistors T9 and T10, voltage equalization circuitry comprising transistor T8, voltage level setting transistors T5 and T6, a resistive circuit means comprising transistor T13, a latching circuit means comprising transistor T7, output level hold circuitry comprising transistors T3 and T4, and load elements comprising transistors T11 and T12. Circuit 10 senses complementary input signals applied to input terminals I and IB (the gate terminals of T1 and T2, respectively) and produces output complementary signals at output terminals O and OB (the drains of T1 and T2, respectively). An input "1" signal applied to terminal I and an input "O" signal applied to terminal IB results in a "1" output signal appearing at terminal 0 and a "0" output signal appearing at terminal OB. Conversely, an input "0" signal applied to terminal I and an input "1" applied to terminal IB results in a "0" output signal at terminal O and a "1" output signal at terminal OB.
In a preferred embodiment, transistors T1, T2, T3, T4, T5, T6, T7, T8, T9, and T10 are all enhancement mode isulated gate field effect transistors, and load devices T11 and T12 and the resistive element T13 each comprises a separate depletion mode insulated gate field effect transistor with the gate of each coupled to the respective source.
The drains of T11 and T12 are coupled together to terminal 12 and to a power supply VCC. The gate and source of T11 are coupled to the drains of T1 and T3 and to output terminal 0. The gate and source of T12 are coupled to the drains of T2 and T4 and to output terminal OB. The sources of T1 and T3 are coupled to the drains of T5 and T9, the source of T8, the gate of T10, and to a terminal 14. The sources of T2 and T4 are coupled to the drains of T6, T8, and T10, the gate of T9, and to a terminal 16. The sources of T5, T6, T9, and T10 and the drains of T7 and T13 are all coupled to a terminal 20. The gate and source of T13 are coupled to the source of T7 and to a terminal 24 which is coupled to a power supply Vref. The gates of T5, T6, and T8 are coupled together to a common terminal 18. The gates of T3, T4, and T7 are coupled together to a common terminal 22.
The drain and source of each of the transistors may be referred to as the output circuitry of that transistor. A circuit element, device, or a circuit terminal which is denoted as being coupled to the output circuitry of a transistor may be coupled to the drain or the source of the transistor.
At the beginning of a cycle of operation of sense amplifier-detector circuit 10, input terminals I and IB are both held at equal potentials of approximately VCC, terminal 22 is held at the potential of Vref, and terminal 18 is held at the potential of approximately VCC. These conditions result in conduction from VCC through T11, T1, the parallel combination of T5 and T9, T13, and to terminal 24 and to Vref, and from VCC through T12, T2, the parallel combination of T6 and T10, T13, and to terminal 24 and to Vref. Thus at this time there are two direct-current paths between VCC and Vref. The impedance levels of all transistors utilized are selected such that terminals 0 and OB are at approximately equal potentials and said potentials are close to that of VCC. In addition, terminals 14 and 16 are at essentially equal potential levels at a value intermediate between that of VCC and Vref.
An input signal and the complement thereof are now applied to terminals I and IB, respectively. Assume that a "0" input signal having a Vref potential level is applied to input terminal I and a "1" input signal having a VCC potential level is applied to terminal IB. Terminal 18 is now pulsed from VCC to Vref and terminal I, which had been held at VCC, is now allowed to drop in potential towards Vref in response to the "0" input signal. This turns off T5, T6, and T8. Thereafter, terminal 22 is pulsed from Vref to VCC. This turns on T3, T4, and T7. In response to T7 turning on, terminal 20 drops in potential towards Vref. This causes terminals 14 and 16 to likewise initially drop in potential. The conductance of T2 is greater than that of T1 because the potential level at the gate thereof is greater than at the gate of T1. This results in terminal 14 dropping in potential at a faster rate than terminal 16. Thus a potential difference between terminals 14 and 16 is created.
The potential difference between terminals 14 and 16 is amplified by cross-coupled transistors T9 and T10. As a result of this potential difference, T9 conducts heavily and thus pulls terminal 14 close to Vref. This turns off T10. Output terminal 0 follows terminal 14 and also reaches a potential level close to Vref. This represents an output "0" signal on output terminal 0. T1 turns off as the input signal applied to terminal I approaches Vref. Output terminal 0 still stays at a value close to Vref since T3, T11, and T9 are on at this time.
T10 is turned off as terminal 14 goes towards Vref and, accordingly, terminal 16 and output terminal OB both rise in potential towards VCC because there is no longer a current path to Vref since T6 and T10 are off. This represents an output "1" signal on output terminal OB.
Thus, it is clear that with "0" and "1" signals applied to input terminals I and IB, respectively, that output "0" and "1" signals result at terminals 0 and OB, respectively. Input terminals I and IB and terminal 18 are now returned to VCC and terminal 22 is returned to Vref. A new cycle of operation of circuit 10 can now begin. If a "1" and a "0" are applied to input terminals I and IB, respectively, then the resulting output signals at terminals O and OB are a "1" and a "0", respectively.
It is to be noted that after the input signals are applied and cross-coupled transistors T9 and T10 have been latched (T7 is turned on), that the output signals appearing at terminals O and OB will not change even if the input signals at terminals I and IB change.
T5 and T6 serve to help equalize the potentials of terminals 14 and 16 and speed up the recovery of circuit 10 to the initial conditions. In some applications T5 and T6 can be elminated.
Sense amplifier circuit 10 has been built as part of a 256 by 8 bit static random access memory that is formed on a single integrated silicon chip that has been tested and found to be functional. All the transistors used are n-channel insulated gate field effect transistors. T1-T10 are enhancement-type transistors and T11, T12, and T13 are depletion mode transistors. The power supply potentials used were VCC=+5 volts and Vref=0 volts. The threshold voltage (Vth), width, and length of each transistor used are given in the table below.
______________________________________ Threshold Voltage Width LengthTransistor Vth (Volts) (Microns) (Microns)______________________________________T1 0.5 30 2.5T2 0.5 30 2.5T3 0.5 50 2.5T4 0.5 50 2.5T5 1.0 5 2.5T6 1.0 5 2.5T7 1.0 170 2.5T8 0.5 10 2.5T9 1.0 60 2.5 T10 1.0 60 2.5 T11 -2.5 10 2.5 T12 -2.5 10 2.5 T13 -2.5 5 10______________________________________
In this embodiment T11, T12, and T13 act essentially as resistors. The sense amplifier was designed to allow detection of a voltage difference on the I and IB terminals as small as approximately 0.1 volts. Thus it is not necessary to wait until the I or IB terminal reaches the Vref potential level to start sensing the input signals. This allows for relatively high speed operation.
It is to be understood that the embodiments described herein are merely illustrative of the principles of the invention. Various modifications are possible within the scope of the invention. For example, depletion mode transistors T11, T12, and T13 can be replaced by standard integrated circuit transistors on a variety of other resistive type elements. Still further, transistors T1, T2, T3, T4, T5, T6, T7, T8, T9, and T10 could be junction field effect transistors. Still further, the transistors could be p-channel field effect transistors providing the power supply polarities were appropriately modified.
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A latching type of sense amplifier, which uses depletion mode transistors as resistive load elements, a pair of enhancement mode field effect transistors as input devices, two other pairs of enhancement mode field effect transistors, and, in addition, a cross-coupled pair of enhancement mode field effect transistors, provides relatively high sensitivity and fast latching time essentially independent of input and output capacitive loading.
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Sequence Listing or Program
[0001] This application contains two embedded controllers programmed with the following firmware. The first, embedded controller 21 (main processing component), runs “Main.hex” firmware. The second, embedded controller 22 (keypad encoder and clock), runs “KeypadClock.hex.”
BACKGROUND—PRIOR ART
[0002] The following is a list of relevant prior art:
[0000]
U.S. Patents
Patent Number
Kind Code
Issue Date
Patentee
6,644,557
B1
Nov. 11, 2003
Jacobs
8,020,780
B2
Sep. 20, 2011
Finch
8,195,313
B1
Jun. 5, 2012
Fadell
[0003] Having been a facilities engineer at a college campus for many years now, I've run into a need for a dual control climate controlling device (thermostat) that gives an administration control of an HVAC system yet allows the room occupant (students in the dorms, professors in the classrooms, persons in chapel, etc.) control as well so they may use the room with reasonable comfort. The climate controlling device must contain a set of tools to perform the necessary functions to allow the two parties the ability to control the HVAC system and satisfy the needs of both. The room occupant needs to have the ability to use the room in comfort and the administration needs to have the ability to set reasonable guidelines and eliminate wasted energy. It is desirable the climate controlling device be a self contained device so that anybody with reasonable skills may install it without the need for professional installation. Not being able to find such a device in the marketplace, I developed it myself. Seeking to secure patent rights, I discovered there is nothing in prior art that describes a thermostat that fits this description.
[0004] Prior art addresses some of the problems associated with giving any person in the room control of the HVAC system but does not address the many problems associated with dual control of an HVAC system. The purpose of dual control is to allow a responsible party such as an administration control over the HVAC system yet also allow the room occupant control over the system as well. Prior art makes many attempts at giving an authoritative body control over the HVAC system. Some devices do so by implementing various limited access features such as password systems or other exclusionary devices. Or, in other instances, they limit the range of temperature settings the room occupant can use by fixed or adjustable settings. This is useful but falls way short of being an effective device for satisfying the needs of both parties. In order to achieve a finely balanced dual control system, a very selective set of functions must be incorporated into the climate controlling device.
[0005] For example, there must be a way for a room occupant, say a professor, to have enough control of the HVAC system to make a classroom he enters comfortable enough to use. He or she must not be excluded from using the classroom because they cannot exhibit any control over the HVAC system. There are many examples in prior art that use exclusionary means, such as a password system, to exclude certain persons from accessing control of the HVAC system, but professors entering a classroom must have the ability to use that room if they need to. The climate controlling device must not cause a professor to be disabled from using a classroom because he either hasn't been told the password or he has forgotten it. Colleges use adjunct professors that are not part of the every day classroom experience hence to rely upon them to know the HVAC passwords for the classroom cannot be relied upon. Also, professors are always calling the IT department because they cannot access a piece of computer software because they forgot a password so relying on all of them to always remember all the HVAC system passwords cannot be relied upon. And a professor starting a class 20 minutes late because he spent that time looking for someone to give him the password to the HVAC system is not acceptable. The alternative, to leave the classroom HVAC system open for anyone to walk in and do what they please is also not acceptable. Another means of control is needed. This present invention allows the administration to shut off the HVAC system because the room is not usually used at certain times but allows the room occupant, in this case the professor, to walk in and use the room without a password by engaging the override feature on the device. He does this simply by pressing the “1” key on the keypad. This will turn the HVAC system on to a comfortable temperature setting that was set by the administration earlier.
[0006] Giving a professor the ability to turn the HVAC system on is good and satisfies his needs but that does not address the problems the administration now has to face with eliminating wasted energy if he forgets to turn it off (and how they forget to turn it off!). If the professor leaves the classroom with the HVAC system still running, there may not be anyone else using the classroom for a long period of time. All the energy used to keep the room at a comfortable level during that time will have been wasted. While this is not a problem for the professor, it is for the administration who will be paying the extra money for the wasted energy on the electric bill. So, among the many software tools this device has to maintain dual control is a timer that automatically shuts the HVAC system off after the override period has timed out. The override time period is adjustable and is set by the administration. Thus both parties have been satisfied. The professor was able to turn the HVAC system on and use the room and the administration has been satisfied because the system did not run wastefully.
[0007] Just as there are times when the administration may turn the HVAC system off but allow the room occupant the ability to turn it on, there may also be times when the administration may want to be able to turn the HVAC system off and not allow anyone to turn it on. This may be the case during the summer time when the campus is shut down, for example. This control can be achieved by the administration and it is explained later. It is the purpose of this device to grant dual control, but also to give the administration final say in that control.
[0008] There must also be a way for an administration, if they want to, to eliminate the wasted energy caused by someone turning the fan switch to “On” instead of “Auto”. This often occurs causing the fan to run for sometimes weeks at a time with no one noticing. Someone in chapel, for example, may turn the switch to on to move the air during a service and leave the room that way. It has often been observed that the fan has been running for weeks and no one knew it. This control can also be achieved by the administration and it, too, is explained later.
[0009] There must also be a way to maintain a balance of control over the HVAC system between the administration and the students in the dorm rooms. The administration needs to have the ability to maintain a sense of order in the dorms by not allowing the students to set the room temperature to a very high or very low level. Students come from all over the world being used to different climate conditions, some from Alaska and some from warmer regions. The thermostat in one room often affects the temperature not only in that room but the rooms next to it. And it has been found that students left in complete control of the HVAC system is not acceptable. The students need to have the ability to make adjustments to make the room comfortable but the administration needs to have control over the HVAC system to make sure the room temperature stays within a reasonable level. Students often turn the A/C down to around 60 degrees and snuggle under blankets in their room. This wastes electricity and causes the air conditioning unit to run almost constantly. It also causes students in the other dorm rooms to complain their room is too cold. There must be a way to maintain a balance of control between the administration and the students. This device does this by allowing the administration to set minimum and maximum settings for both heating and cooling. The students can adjust the room temperature but only within a range set by the administration.
[0010] There must also be a way to keep the room occupant from “playing” with the thermostat trying to make the room cooler and in the process changing the thermostat schedule settings. This problem has been observed frequently. Once again the maintenance department is called to figure out why the A/C is running on a Saturday when no one is there only to find the schedule had been messed up by someone earlier in the week. The administration must have the ability to set a schedule and know that it will remain intact without being tampered with by the room occupant. Also, to require a password to access control of the thermostat as is often stated in prior art is not acceptable since such password access would not only give access to adjust the room temperature settings but also the schedule. Once again, this device addresses these problems where prior art does not.
[0011] Another problem sometimes encountered is the room occupant changing the “Off-Heat-Cool” switch position. While this may be desirable sometimes, sometimes it is not. Often there are several A/C units cooling the same room, hence, if one of them goes bad or has a problem it is not always readily noticed because the other units are working to cool the room. It has been observed many times that the switch on one or more of the units had been placed on heat while the other units were on cool. Once again, it was probably someone in a hurry “playing” with the thermostat trying to make the room colder and they accidentally changed the switch position. It is sometimes desirable for the administration to have the ability to not allow this switch position to be changed by the room occupant. Once again, this device gives the administration such control.
[0012] And the most important thing to be stressed here is there needs to be the ability to perform all of the above tasks in a single device and not just some of them. If all the above problems cannot be addressed together in a single device then the device does not address the problems of dual control and granting the administration ultimate authority over the HVAC system. And the ability to satisfy the needs of a room occupant and an administration have not been met. Exercising one or more of the above features in a device does not fulfill the requirements of dual control and such a device is not useful to me. Nothing in prior art describes a device that can address all these problems.
[0013] There is a long list of prior art shown in U.S. Pat. No.6,644,557 B1 issued to Jacobs on Mar. 25, 2002. While these inventions address the problems associated with allowing anyone entering a room to make changes to the HVAC system control, none of them, including the one just mentioned, solve the problems of dual control of an HVAC system. They provide different lock-out mechanisms and ease of use methods and range controls without providing the very selective set of functions needed to solve the many problems encountered when allowing dual control of an HVAC system.
SUMMARY
[0014] In one embodiment the thermostat has a keypad with 12 keys. These keys are used to input all information into the thermostat. The thermostat displays information back out to the user via an LCD display. In one embodiment this display has 4 lines with 20 characters per line. The administration has the ability to set a vast array of operating parameters by entering the thermostat into administration mode via a password. The thermostat is designed in such a way that this password should never be given to anyone outside of the administration. The room occupant controls the system without the need for a password. When the administration is finished setting up the system's features in the way they want it to operate, they place the thermostat into occupant mode by pressing the pound key.
[0015] The thermostat gives the administration the ability to have full control over the HVAC system yet it allows the room occupant the ability to control the HVAC system as well. The administration determines what that level of control is to be. The administration may enable or disable different features and set minimum and maximum temperature settings for both heating and cooling. Features they can enable or disable are the override switch, the fan switch (on/auto), the off-heat-cool switch, the temp up button, and the temp down button. Only the administration can set the program schedule for the thermostat. The purpose of this device is to give control of the HVAC system to two parties, a ruling party such as an administration and the room occupant, in such a way that the needs of both are met with little adverse affects on the other while at the same time giving the administration ultimate authority over the HVAC system.
DRAWINGS—FIGURES
[0016] FIG. 1 shows the enclosure
[0017] FIG. 2 shows the top side of the circuit board
[0018] FIG. 3 shows the bottom side of the circuit board
[0019] FIGS. 4A to 4C are the schematic
[0020] FIG. 5 shows one embodiment of the display screen
DRAWINGS—REFERENCE NUMERALS
[0000]
11 the enclosure
12 keypad
13 hole
14 display window
15 connector, keypad, 0.1″
16 buzzer, piezoelectric
17 chrystal, 1.8432 MHz
18 variable resistor, 100 k
19 transistor, PN2222A
20 display, 4×20
21 embedded controller, ATMEGA1284
22 embedded controller, ATMEGA168A
23 circuit board
24 relay, 5V 2A latching
25 relay, 5V 2A latching
26 relay, 5V 2A latching
27 voltage regulator, LM7805, 5V
28 bridge rectifier, 1A
29 metal oxide varistor, 56V
30 resistor, 100 ohm, ½ W, 5%
31 resistor, 10K ohm, ¼ W, 5%
32 thermistor, 10K ohm, 5%
33 resistor, 10K ohm, ¼ W, 1%
34 resistor, 10 ohm, flameproof, 5%
35 resistor, 47K ohm, ¼ W, 5%
36 capacitor, 22pf
37 capacitor, 22pf
38 capacitor, 10 uF
39 capacitor, 10 uF
40 capacitor, 10 uF
41 capacitor, 220 uF
42 capacitor, 220 uF
43 diode, 1N914
44 diode, 1N914
45 diode, 1N914
46 diode, 1N914
47 diode, 1N914
48 diode, 1N914
49 diode, 1N914
50 diode, 1N914
51 diode, 1N914
52 diode, 1N914
53 diode, 1N914
54 diode, zener, 15V
55 connector, terminal block, 5.08 mm, 6 position
DETAILED DESCRIPTION
[0066] This paragraph describes FIG. 1 details. One embodiment of the enclosure is illustrated in FIG. 1 . Plastic enclosure 11 is used to contain all the components of the thermostat. Hole 13 in the side of enclosure 11 is used to allow the temperature of the room to be sensed by temperature sensing device 32 ( FIG. 2 ). Keypad 12 is mounted to the outside of enclosure 11 and is thereby accessible. Clear window 14 allows LCD display 20 ( FIG. 2 ) to be seen. In one embodiment the enclosure is 6 inches wide, 5 inches tall, and 1 ½ inches deep.
[0067] This paragraph describes components mounted to circuit board 23 . The front side of circuit board 23 is shown in FIG. 2 and the back side of circuit board 23 is shown in FIG. 3 . All electronic components of the thermostat are mounted/soldered to circuit board 23 . These components include embedded controller 21 (main processing component), embedded controller 22 (keypad encoder and clock), variable resister 18 , buzzer 16 , crystal 17 , thermistor (temperature measuring device) 32 , bridge rectifier 28 ( FIG. 3 ), resistors 30 - 35 , diodes 43 - 54 (diode 54 is a zener diode), capacitors 36 - 42 , keypad connector 15 , terminal block (thermostat wire connector) 55 ( FIG. 3 ), transistor 19 , voltage regulator 27 ( FIG. 3 ), metal oxide varistor 29 ( FIG. 3 ) and relays 24 , 25 , and 26 .
Operation
Hardware
[0068] This section describes components mounted to circuit board 23 shown in FIG. 2 (front) and FIG. 3 (back). All electronic components of the thermostat are connected to circuit board 23 . Embedded controller 21 is the heart and brains of the thermostat and embedded controller 22 is used as the keypad encoder and clock. Variable resistor 18 is used to set the contrast of display 20 . Capacitors 36 and 37 are used in conjunction with chrystal 17 to set the clock of embedded controller 21 to a very precise frequency of 1.8432 MHz. Resistor 30 is used as a current limiter for the backlight LED of display 20 . Transistor 19 is used as a switch to turn on the backlight for display 20 . Resistor 31 is a current limiting resistor for the base of transistor 19 . Display 20 is used to display information to the user.
[0069] Resistor 32 is a thermistor that changes resistance as the temperature changes. It is wired in a voltage divider network with resistor 33 and is used to measure the room temperature. Because accuracy is important, resistor 33 is a 1% tolerance resistor (most resistors are typically rated to be accurate to their rated value within 5%). The voltage is taken from the junction of thermistor 32 and resistor 33 and fed to embedded controller 21 where it is processed in firmware.
[0070] Capacitor 39 is used as a filter capacitor for the Aref pin on embedded controller 21 . Capacitor 38 is used as a filter for the voltage coming from thermistor 32 and ensures a more accurate temperature reading. Capacitor 40 is used as filter for the Vcc power line. Keypad 12 is connected to circuit board 23 through connector 15 . Keypad 12 is used to input information into the thermostat. Buzzer 16 is used to give the user an audible feedback during keypresses and other operations. Diodes 43 and 44 are used for electrical isolation to allow the thermostat to use only one buzzer (instead of two) for both embedded controller 21 and embedded controller 22 . Diodes 45 , 46 , and 47 are all used in conjunction with keypad 12 and are used to drive the interrupt pin on embedded controller 22 to a low state when a key is pressed. Diodes 48 to 53 short the voltage kickback from the relay coils.
[0071] The reverse side of circuit board 23 is shown in FIG. 3 . Bridge rectifier 28 is used to convert the AC voltage from the HVAC system (the 24V AC from its control voltage transformer) to a DC voltage. Capacitors 41 and 42 act as filter capacitors that follow bridge rectifier 28 . Resistor 34 is used as an absorber of a voltage spike should one occur. Metal Oxide Varistor 29 is used to shunt the voltage to a safe level should a voltage spike occur. Voltage regulator 27 is used to regulate the voltage level to 5 volts. Diode 54 is a 15 volt zener diode used to drop the voltage input to the voltage regulator by 15 volts. Relay 24 is used to activate the Y contact of the thermostat. Relay 25 is used to activate the G contact of the thermostat. Relay 26 is used to activate the O contact of the thermostat. (“Is used to activate” refers to connecting the terminal [G, Y, or O] to the power terminal which is the “R” terminal.)
Software
[0072] When the thermostat is first powered up, display 20 will display “Booting . . . ” on line 1 and a second or so later on line 3 will display “Press any key to enter Setup”. During this time if a key is pressed the thermostat will enter Installer mode. The display will read “Enter Password”. Next the master password will need to be entered. If the correct master password is entered the thermostat will display “Installer”. Next press “1” to set the subbase type. If “1” in pressed the display will read “Sub=1” meaning the subbase type is set for heat pump. Press “1” if you want to keep the subbase type as heat pump (or it will time out in a few seconds) or press “2” to set the subbase type to gas heat. The thermostat will time out and recycle back to “Booting . . . ”. During the boot process if no key is pressed when the display reads “Press any key to enter Setup” the thermostat will after a few seconds proceed to normal operation.
[0073] When the thermostat is powered up and operating in normal operation, display 20 will display information as shown in FIG. 6 . The word “Room:” is displayed and next to it is displayed the room temperature, in this case it reads 74 degrees. Below this is displayed the word “Off” or “Heat” or “Cool” which will be indicating the mode the thermostat is currently in. Just to the right of the colon will read the temperature the thermostat is set at. If it is in cooling mode, it will display the cool temperature setting and the same goes for heat. FIG. 6 shows the thermostat set for cooling and it is set for 75 degrees. Below this will be displayed the word “Unit:” and next to it will be the current status of the HVAC system. If the HVAC system is running, it will read “RUN” here. If the thermostat is not running, it will read “Off” here. Below this is displayed the word “Fan:” and next to it it will display the status of the fan switch which is either “Aut” for auto or “On” for on. In this case it is displaying “Aut”. The next set of displayed information starts at column 11 . It will display the mode the thermostat is in. It will either display “Admin” for administration or “Occup” for occupant. In this case it is displaying “Occup” for occupant mode. Below this is displayed the mode of operation, either “Stand” for standard mode or “Sched” for schedule mode. In this case it is displaying “Stand” for standard mode. Below this will be displayed the clock information including the day of the week, the hour, and the minutes and next to this it will read “am” or “pm”.
[0074] To place the thermostat in administration mode, press the “#” key and then enter the proper four digit password. Either one of the three standard passwords can be entered or the master password. The display should now read “Admin”. All the administration functions are now available.
[0075] Pressing the “1” key will display “Set Cool Min”. Below it should be displayed the current cool minimum temperature the thermostat will allow. A new value can be entered at the keypad. For example, pressing the seven key followed by the eight key will change the setting to 78 degrees. This setting is affective when the thermostat is in standard mode.
[0076] Pressing the “2” key will display “Set Cool Max”. Below it should be displayed the current cool maximum temperature the thermostat will allow. A new value can be entered at the keypad. For example, pressing the seven key followed by the three key will change the setting to 73 degrees. This setting is affective when the thermostat is in standard mode.
[0077] Pressing the “3” key will display “Set Heat Min”. Below it should be displayed the current heat minimum temperature the thermostat will allow. A new value can be entered at the keypad. For example, pressing the six key followed by the three key will change the setting to 63 degrees. This setting is affective when the thermostat is in standard mode.
[0078] Pressing the “4” key will display “Set Heat Max”. Below it should be displayed the current heat maximum temperature the thermostat will allow. A new value can be entered at the keypad. For example, pressing the seven key followed by the three key will change the setting to 73 degrees. This setting is affective when the thermostat is in standard mode.
[0079] Pressing the “5” key will display “Override”. Pressing the “1” key next will display “Set OR Length”. Next enter the length of time you want the override to be. This number will be multiplied by 30 minutes. Two numbers need to be entered. So, for example, if you want the override length of time to be one hour you would enter “0” then “2”. If instead of pressing the “1” key after entering the override mode you pressed the “2” key, the display will read “Set OR Cool”. Below it should be displayed the current override cool setting. A new value can be entered at the keypad. For example, pressing the seven key followed by the three key will change the setting to 73 degrees. If instead of pressing either the “1” key to set the override length or pressing the “2” key to set the override cool setting you pressed the “3” key, the display will read “Set OR Heat”. Below it should be displayed the current override heat setting. A new value can be entered at the keypad. For example, pressing the six key followed by the seven key will change the setting to 67 degrees. These settings are used when, for example, a professor enters a classroom unexpectedly and needs to use the room. In warmer weather the administration may have the room temperature set very high to save energy. The professor can, simply by pressing the “1” key, activate the temporary override feature that will turn the HVAC system on to this preset cool temperature setting so he can use the room comfortably and it will shut itself off automatically after the override period times out. He may also turn the override feature off simply by pressing the “2” key as he leaves the room. Either way it will go back to the administration setting that is was set at before the override was activated. In one embodiment the thermostat will beep a few minutes before returning the HVAC system back off to warn the professor his time is about up. In any case, he may press the “1” key again which will start the timeout period all over again.
[0080] Pressing the “6” key will display “Deviation”. Below it will be displayed the current deviation amount the thermostat will allow. A new value can be entered at the keypad. For example, pressing the “2” key will change the deviation amount to 2 degrees. The deviation amount is used when the thermostat is in schedule mode. In this mode the administration has control over the room temperatures and the room occupant has none. The deviation is another software tool that allows the administration to set a schedule of temperature settings but also allow the room occupant to adjust the room temperature somewhat for his or her comfort. That amount is dictated by whatever the administration decides to set the deviation amount to be. For example, if the administration has the schedule set so that at a particular time the (mode is cooling) temperature is set to 75 degrees and the deviation amount is 2 degrees, the room occupant may lower the room temperature down to as low as 73 degrees or raise it to as much as 77 degrees if he so chooses to do so. The idea is to satisfy the administration by giving him control over the HVAC system but yet allow the room occupant to be satisfied by being able to adjust the temperature closer to his comfort level. The deviation may be set anywhere from zero to nine.
[0081] Pressing the “7” key will display the time. The first line displays the day and the second line displays the hours and minutes. Pressing the “1” key will advance the minutes. Pressing the “2” key will advance the hours. Pressing the “3” key will advance the day of week.
[0082] Pressing the “8” key will display the schedule. FIG. 6 shows the schedule as displayed on the screen. The schedule will start by displaying Monday event 1 information. The time will be blinking since it can be set at this point. Pressing the “3” key will advance the minutes to the next 15 minute mark. For example, if the time is 7:12 am and the “3” key is pressed, the time will advance to 7:15 am. Pressing it again will advance it to 7:30 am. Pressing the “6” key will do the same increments only backwards. So, for example, pressing the “6” key when the time is displaying 7:42 am will change the setting to 7:30 am. Keys “2” and “5” are special adjustment keys. They are also used to set the time but in single increments. Pressing the “2” key will advance the time by one minute. Pressing the “5” key will decrement the time by one minute. To advance the schedule to change the cool temperature setting, press the “9” key. (Pressing the “7” key moves the schedule backwards.) Pressing the “9” key again will cause the temperature next to heat to blink indicating the heat setting may now be changed. Pressing the “9” key again will advance the schedule to the next event, in this case Monday Event 2. Once Monday Event 4 is reached, advancing the schedule will move to Tuesday Event 1 and so on.
[0083] Pressing the “9” key will display the lock modes. When the “9” key is pressed, the display will read “Lock Modes”. Pressing the “1” key next will display “Enable Key”. Next press the key you want to enable. Pressing it will enable the key and thus enable the room occupant to use that key's function. If after pressing the “9” key the “2” key was pressed, the display will read “Disable Key”. Pressing a key at this point will disable the key and thus disable the room occupant from using that key's feature. Pressing the “3” key will display “Full Lock”. At this point every key is locked except the “#” key. Pressing the “4” key will display “Full Unlock”. At this point all keys will be unlocked. The purpose of the lock modes is to allow the administration to set what functions they want to allow the room occupant to be able to use. So, for example, if there has been a problem with people turning the fan switch to “On” and leaving the room and the fan is kept running for a long time, the administration may disable the “5” key (fan mode key) and the room occupant cannot change the fan mode from auto to on anymore. The lock modes is a software tool that gives the administration control over the HVAC system and allows them to dictate the amount of control the room occupant can have.
[0084] Pressing the “0” key will display “Passwords”. In order to enter this mode of operation, the master password must have been entered. Pressing the “1” key will display “Sta” meaning standard. Next press “1”, “2”, or “3” for password number one, two, or three. In one embodiment there are three standard passwords. For our example we will press the “1” key. Next enter a four digit password. The thermostat will remember this as standard password number one. We could have pressed the “2” key to save the password as standard password number two. We also could have pressed the “3” key to save the password as standard password number three. Going back to the beginning, pressing the “2” key after pressing the “0” key will display “Mas” for master password. Next enter a four digit password and the thermostat will remember it as the master password.
[0085] Pressing the “#” key will return the thermostat to occupant mode. At this point the administration functions are no longer available. To enter administration mode again, press the “#” key followed by either the master password or one of the three standard user passwords. With the thermostat now in Occupant Mode, the following functions are available to the user. The administration may choose to lock any of the features below by locking the appropriate key as just explained.
[0086] Pressing the “1” key engages the override feature. This will cause the thermostat temperature settings to change from its current settings to the override settings.
[0087] Pressing the “2” key disengages the override feature. When this key is pressed the thermostat settings will return to what they were before the override feature was activated
[0088] Pressing the “3” key raises the temperature setting by one degree. This is true whether the thermostat is in cooling mode or heating mode.
[0089] Pressing the “4” key shifts the mode from “Off” to “Cool” to “Heat”. For example, if the current setting is cooling mode and this key is pressed, the mode will shift to heating. If the current mode is heating and this key is pressed, the mode will shift to off.
[0090] Pressing the “5” key toggles the fan mode between “Auto” and “On”.
[0091] Pressing the “6” key lowers the temperature setting by one degree. This is true whether the thermostat is in cooling mode or heating mode.
[0092] Pressing the “7” key toggles the mode between Schedule mode and Standard mode. When the thermostat is in Schedule mode, the thermostat will follow a schedule for the temperature setting. That is, software will check the day and time of day and assign the temperature setting for that particular time. When the thermostat is in Standard mode, the schedule data is ignored and the thermostat operates as a simple non-programmable thermostat.
[0093] Keys 8-11 (key 9 meaning “*” and key 10 meaning “0” here) are not functional. They are reserved for future use in firmware upgrades.
[0094] Pressing the “#” key followed by a correct password will enter the thermostat into Administration Mode from here. When the thermostat is in Administration Mode and the “#” key is pressed, the thermostat will return to Occupant Mode. (No password is necessary to go from Administration Mode to Occupant Mode.) It also acts as a return key.
Conclusion, Ramifications, and Scope
[0095] The reader may imagine that, with a firmware based electronic system such as this, an exhaustive array of variations are possible and therefor an exhaustive number of embodiments here are possible, but the fundamental or common feature here is to provide a set of software tools that allows dual control of the climate managing system. An administration needs to control the thermostat so that some sense of order may be maintained and wasted energy can be eliminated. But at the same time since the room occupant is actually the one occupying the room and therefor should share in the equation of balance, he should also be able to control the HVAC system. It is this fair balance of control that is the heart of this design. Variations in power supply design, power source, enclosure type, display line count, keypad count or design, number of stages, communications port presence or design, etc. are all important design features, but it is the balance of control between two parties and satisfying the needs of both are the invention's focus. A comprehensive set of operating features has been provided in software to allow such balance possible.
[0096] The features include giving the administration the ability to set a schedule and know that it cannot be tampered with by the room occupant. Allowing the room occupant the ability to turn the HVAC system on and to allow him to do so without a password not only frees him from the burden of having to remember another password in order to use the room but also keeps him from having the ability to effect changes in the schedule (since giving him a password would allow him access to the administration functions). Another part of the comprehensive set of operating features is the ability of the thermostat to return to operating settings set by the administration automatically after allowing the room occupant the ability to control the room temperature enough to comfortably use it. Various fundamental means of adding exclusivity of control by use of passwords, etc. is not effective in maintaining dual control of the HVAC system. A software driven method of complex control arrangements has been provided here to achieve the result of providing a means of control over an HVAC system by two separate parties in order that both parties may achieve their goals. Only two features have been listed here to display the role of dual control, but there are many more incorporated in the design as was seen earlier.
[0097] It could be noted that my examples refer to a college setting with professors, etc., but dual control of the HVAC system is an important control scheme and therefor useful in other settings as well. The college setting is one familiar to me and therefor used in my examples, but these rules apply in many other settings as well. Commercial properties are mainly the focus here, but anywhere where two parties need a balance of control, this invention is extremely useful.
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A dual control climate controlling system (thermostat) that gives the control of an HVAC system to two separate parties—an authoritative body such as an administration of a facility and the room occupant—in a balance of control that satisfies the needs of both parties with minimal detrimental effects to the other. The administration has ultimate control over the HVAC system management and decides how much control it wants the room occupant to have. The administration has a comprehensive set of software driven tools within the device that allow it to enable or disable any control feature of the thermostat. There are automatic features that return control settings back to the administration's settings after allowing the room occupant to make changes to achieve comfort for himself This is a non-deniable system, that is, the room occupant can effect changes without the need for a password.
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FIELD OF THE INVENTION
[0001] The present invention relates generally to communications cables, and more specifically to fiber optic communications cables.
BACKGROUND
[0002] Fiber optic cables include optical fibers which transmit information in cable television, computer, power, telephone systems, and the like. Typically, fiber optic cables include a plurality of optical fibers housed within one or more protective layers, which are conventionally either plastic “loose tube” buffers (see, e.g., U.S. Patent Publication No. 2005/0281517) or jacketed subunits containing tightly buffered optical fibers (see, e.g., U.S. Pat. No. 6,370,303). The number of fibers included in the cable, and the materials and thicknesses thereof used to form the protective layers, are selected based on the type of application or installation of the cable.
[0003] Fiber optic cables often include “fillers” in combination with “active” locations in cable constructions in order to make cables uniform or round. In this definition, “active” locations are fiber-containing positions within a cable construction, whether they be optical fiber-containing plastic loose tube buffers, jacketed subunits containing tight buffered optical fibers, or another fiber optic configuration. One can imagine that assembling three such active positions contained within an elongate cable forms a generally triangular cross-section, four active positions generally resembles a square, and five or more positions begins to define generally a circle, which is often the desired shape of a cable cross-section. These geometries are further complicated by the addition of a central element around which the fiber bearing elements may be stranded. The central element can (a) provide tensile strength, (b) provide columnar strength (anti-buckling), (c) fill a physical void in the construction, (d) actually be an “active” element”, or (e) serve combinations and permutations of any or all of (a)-(d). With this in mind, one skilled in the art will realize that there will be preferred geometries of central and peripheral elements where a specific number of peripheral elements of five or more will in general approximate a round cross-section for an elongate cable.
[0004] It is typical and known in the art that when there are fewer than five active peripheral elements, filler elements of similar size (typically elongate rods) are added to occupy the voids in the periphery in order to achieve the minimum of five desired elements to produce a minimally round cable. It is also typical that fillers are added to constructions of more than five active elements when the number of active elements does not adequately fill or complete the geometric spacing of the peripheral elements. If this were not done, there would be undesirable gaps formed around the periphery of the cable which would create voids, generate flat spots, and allow for undesirable movement of the active elements.
SUMMARY
[0005] As a first aspect, embodiments of the invention are directed to a fiber optic cable. The fiber optic cable comprises: a plurality of optical fibers, the fibers divided into a plurality of subunits, each of the subunits defining generally a circle having a first diameter; at least one elongate filler element, the filler element comprising a cellulosic material, wherein in end view the filler element defines generally a circle having a second diameter that is substantially the same as the first diameter; and an outer jacket surrounding the optical fiber subunits and the filler element, wherein the total number of fiber optic subunits and fillers elements is at least four. In this configuration, the cable can pass typical flame testing while being manufactured at a lower cost than current cable, and/or may provide for reduced anti-buckling elements within the cable construction.
[0006] As a second aspect, embodiments of the invention are directed to a fiber optic cable, comprising: a plurality of optical fibers, the fibers divided into a plurality of subunits, each of the subunits defining generally a circle having a first diameter; at least one elongate filler element, the filler element comprising a cellulosic material, wherein in end view the filler element defines generally a circle having a second diameter that is substantially the same as the first diameter; and an outer jacket surrounding the optical fiber subunits and the filler element, wherein the total number of fiber optic subunits and fillers elements is at least four. The cellulosic material comprises a fire-retarding agent.
[0007] As a third aspect, embodiments of the invention are directed to a fiber optic cable, comprising: a plurality of optical fibers, the fibers divided into a plurality of subunits, each of the subunits defining generally a circle having a first diameter; at least one elongate filler element, the filler element comprising a cellulosic material and a water blocking agent and/or an anti-wicking agent, wherein in end view the filler element defines generally a circle having a second diameter that is substantially the same as the first diameter; and an outer jacket surrounding the optical fiber subunits and the filler element, wherein the total number of fiber optic subunits and fillers elements is at least four.
BRIEF DESCRIPTION OF THE FIGURES
[0008] FIG. 1 is a perspective section view of a fiber optic cable according to embodiments of the invention.
[0009] FIG. 2A is a perspective section view of a filler element of the fiber optic cable of FIG. 1 .
[0010] FIG. 2B is a perspective section view of a filler element according to alternative embodiments of the invention.
[0011] FIG. 2C is a perspective section view of a filler element according to additional embodiments of the invention.
[0012] FIG. 3 is a perspective section view of a fiber optic cable according to further embodiments of the invention.
DETAILED DESCRIPTION
[0013] The present invention will be described more particularly hereinafter with reference to the accompanying drawings. The invention is not intended to be limited to the illustrated embodiments; rather, these embodiments are intended to fully and completely disclose the invention to those skilled in this art. In the drawings, like numbers refer to like elements throughout. Thicknesses and dimensions of some components may be exaggerated for clarity. Well-known functions or constructions may not be described in detail for brevity and/or clarity.
[0014] 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.
[0015] The terminology used herein is for the purpose of describing particular embodiments only 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 “comprises” and/or “comprising,” 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. As used herein the expression “and/or” includes any and all combinations of one or more of the associated listed items. In addition, spatially relative terms, such as “under”, “below”, “lower”, “over”, “upper” and the like, may be used herein for ease of description to describe one element or feature's relationship to another element(s) or feature(s) as illustrated in the figures. It will be understood that the spatially relative terms are intended to encompass different orientations of the device in use or operation in addition to the orientation depicted in the figures. For example, if the device in the figures is turned over, elements described as “under” or “beneath” other elements or features would then be oriented “over” the other elements or features. Thus, the exemplary term “under” can encompass both an orientation of over and under. The device may be otherwise oriented (rotated 90 degrees or at other orientations) and the spatially relative descriptors used herein interpreted accordingly.
[0016] Referring now to FIG. 1 , a stranded loose tube cable, designated broadly at 10 , is illustrated therein. The cable 10 includes a plurality of buffer tubes 12 (four buffer tubes 12 are shown in FIG. 1 ), each of which houses multiple optical fibers 14 , stranded (i.e., typically wrapped in a shallow helix) about a central strength member 16 . A core wrap 18 may be wrapped around the buffer tubes 12 . A protective outer jacket 20 is disposed over the core wrap 18 . An optional ripcord 22 is provided near the interface of the wrap 18 and the outer jacket 20 . Water-blocking gel 19 or other water-blocking material is typically disposed within the buffer tubes 12 , and may also be disposed on the exterior of the buffer tubes 14 , within the core wrap 18 , if desired. These components are described in greater detail below.
[0017] The optical fibers 14 are long, slender strands that are capable of carrying and propagating an optical signal. More particularly, optical fibers serve as a medium for transmitting light by virtue of a phenomenon known as total internal reflection. Optical fibers typically have a glass or, on occasion, plastic core that is enveloped by an outer concentric shell or cladding. The cladding is generally made from glass and has a relatively low index of refraction with respect to the core. Because of the difference in the index of refraction between the core and the cladding, light rays striking the cladding at an angle greater than or equal to a critical angle (φ c ) will be reflected back into the core at an angle of reflection equal to the angle of incidence. Inasmuch as the angles of incidence and reflection are equal, the light ray will continue to zig-zag down the length of the fiber. If a light ray strikes the cladding at an angle less than the critical angle, however, the ray will be refracted and pass through the cladding, thus escaping the fiber.
[0018] Those skilled in this art will recognize that any number of optical fiber constructions may be suitable for use with the present invention. In particular, optical fibers having a thickness between about 200 and 300 microns are often employed and maybe suitable for use in fiber optic cables according to embodiments of the present invention. Other desirable physical and performance properties include those exhibited by single mode fibers with zero water peak (ZWP), which allow transmission in the E band (1360-1460 nm), and high bandwidth multimode fibers. Exemplary optical fibers are “LightScope” ZWP Single Mode or “LaserCore” multimode optical fibers, available from CommScope Inc., Hickory, N.C.
[0019] Referring again to FIG. 1 , the central strength member 16 provides rigidity to the cable 10 . The strength member 16 is typically formed of a dielectric material such as glass-reinforced plastic, or may be formed of a metallic material such as steel. The strength member 16 may also include a polymeric coating in some embodiments.
[0020] Additional information regarding the components discussed above is included in U.S. Patent Publication No. 2005/0281517, the disclosure of which is hereby incorporated herein in its entirety.
[0021] As can be seen in FIG. 1 , the cable 10 also includes two elongate filler elements 30 . Prior fillers typically used in the industry are made of plastics, in particular solid or foamed polyethylene. These materials are adequate for use in non-flame rated cables typically found in outdoor applications, but can troublesome for flame-rated cables typically required for indoor use due to their combustibility and smoke generation when ignited. Typical flame, smoke and toxicity ratings are established by International, National and Regional safety and governing bodies. Testing for compliance and listing of these cables is carried out by certified/recognized testing authorities such as Underwriters Laboratories (UL), ETL, CSA, NFPA, etc. Achieving limited flame intensity, limited amount of flame spread, and limited smoke density when a flame-rated cable is burned are all requirements for achieving various indoor flammability and toxicity ratings for flame-rated categories of cables. In order to pass the stringent burn testing of these indoor cables (see, e.g., NFPA 262, Standard Method of Test for Flame Travel and Smoke of Wires and Cables for Use in Air-Handling Spaces), inexpensive commodity plastics (like polyethylene) are normally replaced with much higher cost engineered resins in the fluoropolymer family (e.g., FEP, PVDF and PFA), heavily modified PVC, or other plastics. The use of these considerably more expensive plastics for just the purpose of filling space in the cable drives up the cost of the cables to a significant degree.
[0022] To potentially address some of these issues, the filler elements 30 of the cable 10 of FIG. 1 are formed of cellulosic material (such as craft paper, cardboard or crepe/tissue paper) and are sized to be approximately the same diameter and length as a buffer tube 18 . As such, the filler elements 30 are able to provide a spacer in the cable 10 that occupies space that would otherwise be occupied by a buffer tube 18 , thereby enabling the cable 10 to maintain a desirable configuration (e.g., a generally round configuration as described above, with five or more “sites”, although cables with a total of only four “sites”, including cable subunits and filler elements, are also contemplated). The use of cellulosic materials may reduce the cost of flame-rated cable constructions considerably and/or provide for reduced anti-buckling elements within the cable 10 , whether the cable 10 is flame-rated or not.
[0023] In some embodiments (for example, the filler element 30 shown in FIG. 2A ), paper or other cellulosic material may be twisted longitudinally into a tight, substantially solid circular cross-section. In such embodiments, the filler element 30 may include a central spine 31 , which is typically formed of fiberglass or another fiber, such as aramid, that can provide strength, stiffness and/or a foundation about which the cellulosic material is twisted or wound. Exemplary materials include paper products 2616-60, 2216-60, 1916-30, 1416-30 and 1216-30 available from PlymKraft Inc., Newport News, Va.
[0024] In other embodiments, the filler element may comprise a hollow tube, such as the filler element 30 ′ of FIG. 2B . In further embodiments, the filler element may comprise paper or cardboard twisted into an open spiral, such as the filler element 30 ″ of FIG. 2C , which from an end view defines a circular shape (as shown by the dotted line in FIG. 2 ). The filler element 30 ″ may include a central spine 31 ″ of the type discussed above. Other configurations having a generally circular shape in end view may also be employed.
[0025] In some embodiments, the filler elements 30 comprise fire-retardant treated paper. In this configuration, the filler element 30 may replace a more expensive engineered plastic filler elements such as are discussed above and commonly employed. An exemplary fire-retardant treated paper is DuoFlame™ paper, available from PlymKraft, Inc. In other embodiments, untreated paper may produce sufficiently low flame, caloric content and/or toxicity to pass some flame-rating testing.
[0026] In other embodiments, the filler elements 30 may be treated with or incorporate a water-blocking agent and/or an anti-wicking agent. The use of water-blocking agents may assist the cable 10 in preventing water migration down its longitudinal axis. The use of anti-wicking agents may prevent the wicking of water along the length of the filler element 30 . Exemplary water-blocking agents include super absorbent powders, such as Cabloc™ 80HS-A powder, available from Stewart Superabsorbants, Taylorsville, N.C. Exemplary paper with anti-wicking agents include Duo Plym™ paper, available from PlymKraft. An exemplary anti-wicking agent is RUCO-DRY™ water repellent, available from The Rudolf Group, Rock Hill, S.C.
[0027] The use of cellulosic materials in filler elements may also provide additional benefits in stress reduction. Fiber optic cables are designed to protect and limit the magnitude of physical stress that is imparted to the actual optical fibers contained within the cable. Stress can be imparted in many ways, such as elongation, compression, bending, and torsion. Stress above a certain magnitude in any of these stress modes can degrade the performance of optical transmission and can also lead to fracture of the optical fiber. Most materials, and particularly plastic materials, shrink when their temperatures decrease according to a defined rate (known as the coefficient of thermal expansion). Most plastics used in optical fiber cable constructions, such as polyethylene and the fluoropolymers mentioned above, tend to shrink at orders of magnitude greater than the glass composition of the optical fiber contained within. The forces that arise from shrinkage are determined by not only the materials involved, but also the mass and/or volume of the materials used. In fiber optic cables, the amount of plastic utilized and the typically large coefficients of thermal expansion can create high shrinkage/contraction forces in a cable as the cable becomes cold. As a result, cables are constructed to minimize the amount of plastic and also encompass mechanical elements which resist the shrinkage forces. These elements are typically called anti-buckling elements and normally consist of fiberglass encased in an epoxy to form stiff elongate members. The additional member(s) resist or offset the shrinkage forces when the cables experience cold temperatures and prevent undue compressive stresses from being transferred to the optical fiber. Anti-buckling elements of this nature are expensive and constrain the design freedom of the cables.
[0028] In contrast, cellulosic materials, and in particular paper, have a much lower coefficient of thermal expansion (CTE) than typical plastic materials. For example, cellulosic materials may have a CTE of between about 2.0 and 3.0 μin/in/° F., whereas polyethylene has a CTE of about 111 μin/in/° F. and PVDF has a CTE of about 71 μin/in/° F. Thus, the substitution of cellulosic filler elements for plastic fillers can produce either a reduction in the quantity of anti-buckling material or elements needed in a cable or better performance at lower temperatures with a given amount of anti-buckling. In addition, the nature of cellulosic materials like paper may cause the filler element to crack, fracture, tear or otherwise “give” to relieve compressive stress induced by temperature changes, which can reduce the force applied to the fiber elements 30 on the cable 10 due to temperature changes.
[0029] Moreover, the substitution of cellulosic filler elements for plastic filler elements can reduce the weight of the cable. A reduction in weight typically saves on freight cost and improves installation and handling characteristics.
[0030] Another fiber optic cable, designated broadly at 110 , is shown in FIG. 3 . The cable 110 is a tightly buffered cable, and includes tightly buffered optical fibers 114 and aramid yarns 115 within a plurality of jackets 112 , each group of fibers and yarns within the jacket forming a subunit. The cable 110 also an outer jacket 120 , an optional ripcord 122 , and filler elements 130 of the type discussed above in connection with the cable 10 . The tightly buffered cable 110 can enjoy the advantages discussed above in connection with the cable 10 . The filler elements 130 can provide the same types of advantages in tightly buffered fiber optic cable as in loose tube fiber optic cable.
[0031] The invention will now be exemplified by the following example. This example is included to demonstrate embodiments of the present invention and is not intended to be a detailed catalog of all the different ways in which the present invention may be implemented or of all the features that may be added to the present invention. Persons skilled in the art will appreciate that numerous variations and additions to the various embodiments may be made without departing from the present invention. Hence, the following descriptions are intended to illustrate some particular embodiments of the invention, and not to exhaustively specify all permutations, combinations and variations thereof.
EXAMPLE
[0032] Table 1 below includes property information regarding exemplary cellulosic materials and compares them to materials used in prior filler elements.
[0000]
TABLE 1
Combustion
Combustion
Usage Rate
Mass
Energy
Energy - Use
Material
(ft/lb)
(lb/1000 ft)
BTU/lb
(BTU/1000 ft)
0.109″
430
2.32
4,925
11,426
DuoPlym
(moisture
resistant)
0.109″
430
2.35
5,500
12,925
DuoFlame
(flame
resistant)
2616-60
450
2.22
4,725
10,500
1916-30
675
1.48
4,760
7,050
1216-30
960
1.04
5,030
5,241
Polyethylene
313
3.20
20,000
64,000
PVDF
310
3.22
5,800
18,676
[0033] Table 1 demonstrates that multiple cellulosic materials can produce less combustion energy than (a) polyethylene material typically used in non-flame-rated cables and (b) PVDF material often used in flame-rated cables.
[0034] The foregoing is illustrative of the present invention and is not to be construed as limiting thereof. Although exemplary embodiments of this invention have been described, those skilled in the art will readily appreciate that many modifications are possible in the exemplary embodiments without materially departing from the novel teachings and advantages of this invention. Accordingly, all such modifications are intended to be included within the scope of this invention as defined in the claims. The invention is defined by the following claims, with equivalents of the claims to be included therein.
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A fiber optic cable includes: a plurality of optical fibers, the fibers divided into a plurality of fiber optic subunits, each of the subunits defining generally a circle having a first diameter; at least one elongate filler element, the filler element comprising a cellulosic material, wherein in end view the filler element defines generally a circle having a second diameter that is substantially the same as the first diameter; and an outer jacket surrounding the optical fiber subunits and the filler element, wherein the total number of fiber optic subunits and fillers elements is at least four. In this configuration, the cable can pass typical flame testing while being manufactured at a lower cost than current cable.
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FIELD OF THE INVENTION
This invention relates to sharpening metal members such as spikes and the like, and in particular relates to sharpening those members by a rotary tool in the nature of a hollow arbor upon which cutting members are mounted.
BACKGROUND OF THE INVENTION
It is often necessary to form a conical, tapered or similar shape on the end of an elongated member. In the past this has been done using rotating, arbor-type arrangements in which a cutting blade or blades are carried by a hollow, rotatable tool head within which the cutting blades are arranged so as to act upon an elongated member inserted thereinto. The rotating arbor design of a conventional pencil sharpener is an example of this broad type of apparatus. In such an apparatus, the elongated object is inserted into the rotatable arbor, usually during rotation of the arbor or just before the beginning of rotation, whereupon angled blades mounted upon the exterior of the arbor contact the end of the pencil and shave wood from the surface to form a point. The blades are usually held in place by threaded tension studs. In this type of apparatus, a scroll or strip of wood shavings is expelled from the side of the arbor as angled blades mounted upon the arbor contact the surface of the end of the pencil. While such an arrangement is relatively effective for shaving wood chips from a wooden member, whether in the form of a pencil or wooden dowel, such an arrangement is not particularly suitable for operating upon extremely hard objects, such as metal spikes and the like.
One form of metal spike or stud that frequently requires replacement or sharpening are the studs used in conjunction with snowmobile treads. Such studs are secured into the structure of the snowmobile tread for engagement with the snowy and, particularly, icy surfaces over which the snowmobile passes. Without the studs, the tread tends to slip upon such surfaces, thus considerably impeding the forward movement of the snowmobile. Even though these studs, which are customarily screwed into the tread structure, are considerably harder and tougher than snow and ice, because the studs are continuously exposed to abrasion from the constantly changing frozen surfaces over which the snowmobile travels, the studs are rather quickly worn back and lose their sharpness. Also, snowmobile studs are frequently exposed not only to consolidated and unconsolidated snow surfaces and icy surfaces, but also are exposed to ground or earth surfaces including rock surfaces where the snow and ice cover is relatively sparse or thin, or even entirely lacking.
In view of the abrasion and scouring to which the studs are exposed, snowmobile tread studs very rapidly become dull and must either be sharpened or replaced. Under poor snow conditions where the studs may frequently contact ground surfaces, the studs may wear out and require renewal every few days. Renewal is customarily accomplished by unscrewing the studs from the treads and replacing them with new or refurbished or reclaimed studs. Since it is difficult to collect and resharpen the removed studs, the replaced studs are customarily discarded when the new studs are screwed into the tread. However, in some instances the removed studs, and reinstalled in the tread as reclaimed studs.
Replacement of the entire stud is time-consuming and uneconomical, but no good alternative is available. There is therefore, a need for an easy method and means for sharpening snowmobile studs while the studs are still mounted in the snowmobile tread. Moreover, there is need for a tool to sharpen studs and elongated members in general.
Various prior tools for forming sharpened ends on elongated cylindrical and other members are available as described, hereafter, but none of these tools has provided a suitable arrangement for sharpening or resharpening snowmobile tread studs and the like while the studs remain.
Examples of prior art means for sharpening the ends of various types of elongated members are disclosed in the following U.S. patents, U.S. Pat. No. 828,632, issued Aug. 14, 1906 to I. W. Sprink, discloses a hollow milling cutter for thread cutting or general milling. The cutter is provided with a hollow central section surrounded by a generally solid outer section. Four radial grooves are provided in the sides of the head. These grooves accommodate flat tool bits which may slide radially in the slots. Each tool bit is provided with a projecting stud at the rear thereof which fits into an inclined camming slot in a circular plate having a knurled outer surface enabling the plate to be turned. When the knurled circular plate is turned, the studs at the rear of the tool bit are propelled inwardly or outwardly by the camming slots. There are no specific chip orifices except for the open end of the bit.
U.S. Pat. No. 1,368,459 issued Feb. 15, 1921 to J. E. Sheuman, discloses a cutter head having a series of sliding cutting tools which may be adjusted inwardly or outwardly by means of a screw adjustment. The inner ends of the cutting tools may be used to cut or form the outer surface of a cylindrical surface, and the outer ends of the cutting tools may be used to cut the inner side of a hollow cylindrical surface. A central shank is provided for mounting in the chuck of a power tool.
U.S. Pat. No. 1,688,558, issued Oct. 23, 1928 to O. Severson, discloses a hollow milling tool in which the cutting blades or bits are mounted in segmented sections that may be moved inwardly and outwardly. The blades are fitted into slots in the segmented sections. The cutting blades are essentially wedged into the slots, and there are no chip orifices provided adjacent the blades for the removal of chips.
U.S. Pat. No. 1,721,378, issued July 16, 1929 to G. J. Draeger, discloses a so-called floating tool holder wherein cutting blades or bits are pivotally mounted in the arms of a floating tool holder mounted, in the bottom and sides of a cylindrical bit by means of a set screw.
U.S. Pat. No. 3,335,526, issued Aug. 15, 1967 to C. P. Weiss, discloses a pipe scarfing tool in which a more or less conical, internally abrasive cone is mounted on the end of a hand drill. The scarfing tool is provided with a central rotatable mandrill to hold the pipe against the inclined inner abrasive surface. A series of shaving or chip orifices is provided at the bottom of the central opening of the tool to allow escape of chips and dust. No tool bits or cutters are shown since the scarfing of the pipe is accomplished by the abrasive internal surface.
U.S. Pat. No. 4,234,276, issued Nov. 18, 1980 to G. D. Meier, Jr., discloses an off-set dresser for dressing the ends of conical electrodes. A tool bit having a conical opening is mounted in a slot in a central tool bit having an outer retainer, nut or cover. The nut is threaded onto the chuck to hold the dressing blade in place. The end of the electrode which is to be dressed is inserted into a hole or orifice in the top of the nut so that it is dressed by the rotating tool.
U.S. Pat. No. 4,295,763, issued Oct. 20, 1981 to J. Cunniff, discloses a plug cutter for the shaping of wooden plugs. The plug cutter makes use of a series of upwardly extending blades mounted on the sides of a rotating chuck or holder. The blades may be angled at different upwardly extending angles by the use of shims so that a series of conical or cylindrical faces may be formed on the plug.
U.S. Pat. No. 4,449,328, issued May 22, 1984 to R. H. Gillett et al., discloses a honing tool for an exterior cylindrical surface. A honing stone is mounted on a pivoting arm which may be cambered inwardly by a sliding arrangement on an outer sheath. A series of honing stones may be used, each provided with a wedge for moving it radially inwardly.
U.S. Pat. No. 4,798,503, issued Jan. 17, 1989 to B. M. Huju, discloses a tenon forming tool for the formation of tenons, particularly on the ends of fence rails. The tool is designed for use on the end of a hand drill and has a plurality of cutter blades mounted on a conical tool surface for shaving the ends of timber. Each cutting blade is mounted adjacent a chip orifice in the conical surface, and there are additional chip orifices at the bottom of the tool where the cylindrical portion of the tenon extends. The cutting blades are mounted by set screws on the interior surface of the conical portion of the tool adjacent the chip orifices. Consequently, the arrangement depends entirely on the strength of the set screws which secure the cutting blade to the conical surface of the tool. The fastening screws which fasten the blades to the surface are, placed in shear, which provides undesirable arrangement.
As pointed out above, there has been a need for a practical means for sharpening the ends of spikes, studs and other elongated metal members by a relatively simple and easy to use arrangement.
OBJECTS OF THE INVENTION
It is an object of the present invention to provide a device that may be used directly upon snowmobile spikes or studs to resharpen worn or dulled studs, without removing the studs from their normal mounting.
It is a another object of the invention to provide a relatively simple and inexpensive device that can be used to quickly and conveniently sharpen elongated members, such as snowmobile studs, in situ.
It is a further object of the invention to provide a rotatable arbor-type device that can be mounted in a portable hand-held power tool to sharpen elongated members, particularly snowmobile studs, in situ.
It is a still further object of the invention to provide a method and means for sharpening snowmobile studs while the studs are still mounted in a snowmobile tread by using a simple and convenient device that can be used by a relatively unskilled person for on-the-spot sharpening.
It is a still further object of the present invention to provide a simple and convenient method for sharpen elongated members embedded at one end in a second body by using rotatable device.
It is a still further object of the invention to provide a rotatable arbor head which has a plurality of chip discharging slots therein.
BRIEF SUMMARY OF THE INVENTION
The present invention provides a method for sharpening the studs in snowmobile treads without removing the studs from the treads. The invention further provides a rotatable device for accomplishing the sharpening of snowmobile studs and other elongated work pieces which require tapered ends. The device of the invention includes a rotatable arbor mounted upon a shank or spindle adapted for mounting in the chuck of a portable drill or other rotary-type power tool. The head of the arbor has a central, conically tapered opening coaxial with the axis of rotation of the arbor. The tapered opening preferably has inside dimensions approximately the same size as or somewhat larger than the desired outside dimensions of the conical or other taper to be applied or maintained upon the end of the work piece. At least four slots in the arbor extend completely through the arbor wall and provide slots for mounting cutting blades. The arbor is designed to rotate clockwise when in use. The leading wall of each slot relative to the clockwise rotation is provided with a threaded opening therethrough which accommodates a set screw-type mounting member. The following wall (opposite the leading wall) of each slot provides a cutting member abutment surface against which the cutting member is seated during cutting operations. Each slot has a width greater than the thickness of the cutting member. When each cutting member is properly seated within each slot against the following wall abutment surface, there is a clearance between the leading edge of the cutting member and the leading wall of the slot. This clearance is sufficient to accommodate chips cut from the surface of the work piece by the cutting blades.
A mounting member or set screw extends through the threaded opening in the leading wall of each slot. The set screw is rotated all the way toward the following wall and the cutting member within the slot, contacts the side of the cutting member and secures the cutting member in place against the abutment or following wall.
When the device is mounted in a rotary power tool and rotated in the proper direction, the cutting member is held securely against the abutment wall and has a cutting surface at the edge thereof which extends from the slot into the central conically tapered opening. The cutting surface removes small chips or cuttings from the surface of the work piece. The force of the cutting operation against the cutting member is transferred to the abutment or following wall of each slot.
The cutting member is preferably a triangularly shaped blade having three cutting edges, and the side angles of each blade are variable.
The method of the invention involves mounting the rotatable cutting device of the invention in a portable drill or the like, maneuvering a snowmobile onto its side to expose the protruding ends of the tread studs and applying the rotating cutting device head sequentially against the ends of the studs in order to sharpen the ends of the studs by shaving chips from the edges thereof.
It is necessary to have at least four cutting members in the device head in order to effectively cut and sharpen the studs without binding and damaging the cutting members or the stud. Only a few seconds contact between cutting members and the work piece is usually necessary to effect the proper sharpening of the work piece.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an isometric, exploded view of the rotatable cutting device of the invention.
FIG. 2 is a section view of the cutting device of the invention taken along the line 202 of FIG. 1.
FIG. 3 is a section view of the invention taken along the line 3--3 of FIG. 2.
FIG. 4 is an end view of the cutting device of the invention.
FIGS. 5-7 are side views of snowmobile studs showing different angles on the studs.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present invention is directed to a method and apparatus for providing a taper on an elongated member and particularly for maintaining a desirable taper on the studs or spikes located in snowmobile treads. Such studs are usually threaded and are either screwed directly into the tread structure or are screwed into internally threaded fittings in the nature of nuts with accompanying washers disposed on the top and bottom of the tread. Some snowmobile treads are provided in addition with cleats in the form of angle sections attached to the surface of the tread to receive the studs.
Referring in greater detail to the various figures of the drawings wherein like reference characters refer to like parts, the rotatable cutting tool 10 of the present invention is generally shown in FIG. 1. The rotatable cutting tool 10 is comprised of a cylindrical head 102 having at one end a central tapered opening 104 and at the other end a shank 106 for mounting the cutting tool 10 in a power tool, such as a rotatable drill 400. The head 102, central opening 104 and shank 106 are coaxially aligned.
As shown in FIG. 4, grooves 108 extend through the outer circumference 110 of the head 102 to the central opening 104. The grooves 108 provide mounting locations for a plurality of cutting members in the form of triangular blades 202, 204, 206 and 208 which are positioned against one of the walls of each of the grooves and extend along one edge into the central tapered opening 104.
In the preferred embodiment, the wall of each groove 108 against which each blade 202, 204, 206 and 208 is positioned is an abutment wall whose exposed surface faces the direction of rotation of the cylindrical head 102. As shown in FIG. 2, when the head 102 is rotated clockwise (arrow A) by the power tool 400, the blades 202, 204, 206 and 208 are positioned against the abutment walls, 112, 114, 116, and 118, respectively. These abutment walls 112, 114, 116, and 118 are those walls which face in the direction of rotation of the head 102.
Each cutting blade, 202, 204, 206 and 208, therefore, is supported during rotation of the head 102 against its respective abutment wall 112, 114, 116, and 118 with only its narrow cutting edge 210, 212, 214 and 216 extending beyond the abutment walls into the central opening 104.
When the cutting tool 10 of the invention is used for sharpening the studs of a snowmobile tread, the tool 10 is designed to rotate in a clockwise manner, the power tool 400 upon which the tool 10 is mounted being adapted to rotate the tool 10 in a clockwise direction. It is customary to have right-handed threads on the studs, and during sharpening, the sharpening tool 10 should rotate in a direction that will tend to tighten, rather than unscrew, the stud within the tread.
The abutment walls 112, 114, 116 and 118 of the grooves are spaced a sufficient distance from their respective opposing walls within each groove, so that when the blades 202, 204, 206, and 208 are positioned within the grooves, a distance or opening 120 is provided between each blade and the opposing wall. This chip opening 120 is necessary to permit the chips and cuttings removed from the surface of a stud during sharpening, which may otherwise be thrust into the central opening 104, to exit from the head 102. The distance of the opening 120 must be sufficient to allow passage of substantially all material removed from the stud, although some chips may also enter the center of the opening 104 and ultimately exit through the open end thereof.
Opposite and perpendicular to each abutment wall 112, 114, 116 and 118 is a threaded bore 122, 124, 126, and 128, respectively, extending through the head toward the abutment wall. A set screw 302, 304, 306 and 308 is screwed into each threaded bore 122, 124, 126 and 128, respectively. Each set screw 302, 304, 306 and 308 is screwed into its respective bore and into the adjoining groove 108 until the screw contacts the respective cutting blade 202, 204, 206, or 208 within the groove 108. Each set screw preferably has a tapered end 302a, 304a,306a, and 308a which contacts an opening 222 in each blade, as will be explained later. As each set screw is tightened, it securely enters the corresponding hole 222 and holds the blade 202, 204, 206 or 208 within the groove against the respective abutment wall 112, 114, 116, and 118.
As shown in FIG. 3, when the bottom of each triangular cutting blade 202, 204, 206 and 208 (see 208a and 204a) is mounted flush against the bottom of the respective groove 108 and the set screws 302, 304, 306 and 308 are securely pressed against the outer side of the cutting blades 202, 204, 206 and 208, each cutting blade is very securely held in place within its groove 108 with the cutting edge 210, 212, 214 and 216 of the blade extending a very short distance into the central opening 104. In this position, the cutting edge contacts the surface of any tapered object, such as a stud 500 (dashed lines in FIG. 3), pressed into the central opening 104. Such an arrangement is particularly secure and convenient.
It has been found to be important for sharpening snowmobile studs in place on the treads of a snowmobile for the rotatable cutting tool 10 to have four grooves 108 in its surface, with a cutting blade 202, 204, 206 and 208 mounted in each groove as explained above. The cylindrical head 102 of the rotatable cutting tool 10 is placed over the end of each stud 500, preferably while not rotating, and then the electric drill 400 is operated at low speed for a short period while pressure is applied through the cylindrical head 102 to the end of the stud 502. The four triangular cutting blades 202, 204, 206 and 208 rotating about the stud 500 shave the surface of the stud, resharpening it so that it will readily penetrate the surface of deposits of snow and ice and preventing the treads of the snowmobile from slipping during usage.
It is desirable for the cutting tool to be operated in the low r.p.m. range since the operation is in fact a cutting operation and not a grinding or abrading operation and such cutting operation operates best at low speed. Each stud can be sharpened in 5 to 10 seconds, or less, even at very low cutting speed.
At stated above, it has been found that at least four cutting blades are necessary to prevent shattering of the blades upon the ends of the studs with concomitant destruction of both the blades and damaging of the tapered stud surface. This requirement may be related to the fact that the studs are mounted in a rubber tread member and are therefore subject to more than normal vibration. Since the cutting tool is mounted on the end of a rotary drill and is applied by hand to each individual stud, it is subjected to considerable stress and vibrational wear, and it is important that the cutting tool be very strong and that the blades be mounted securely in the head. The arrangement of the invention provides such secure mounting and strength of the head. It is noted, for example, that the major portion of the force of the rotation of the cutting head upon each cutting blade is taken directly by a abutment wall within the groove 108, while the blade is maintained stationary against the wall by its respective set screw. Unlike some blades secured within rotating heads by threaded means where the force against the blade accompanying the cutting action is largely taken in tension against the threaded members, in the present arrangement not only is the major force against the blade taken by the abutment wall, but any force tending to separate the blade from the wall is taken not in tension, but in compression against the set screw.
It has been found that while it is necessary to have at least four grooves and four blades 202, 204, 206 and 208 in the cutting head 102 in order to allow efficient cutting or shaving of the heads of the studs without damage to the cutting blades or the stud surface, it is, in general, desirable not to have more than four grooves or cutting blades in the head unless special high-strength materials are used to form the head 102 or the head is treated to provide more than the usual strength. The head 102 can also be made more massive by increasing its outside diameter relative to the diameter of the conical or center opening 104 to provide more mass for support of the set screws 302, 304, 306 and 308 therein. In such instances, it may be possible to increase the number of grooves and cutting blades in the head beyond the preferred four cutting blades. However, it will be understood that the diameter of the head cannot be increased without limit because of the additional weight which would be entailed and the clearance required to fit the rotatable head over studs which are closely spaced with respect to each other on the tread. A further consideration is that the larger the diameter of the rotating tool, the more expensive such tool becomes and the more power is necessary to rotate it. However, it may be advantageous, in some instances, to increase the diameter of the rotating head or the strength of the materials of which the head is constructed in order to accommodate additional grooves and cutting blades and thereby possibly increase the smoothness of operation during sharpening of the tread spikes.
As shown in FIG. 1 the set screws 302, 304, 306 and 308 are preferably hexhead-type set screws which may be turned by the end of a hexagonal exterior wrench as known to those skilled in the art. That is, the head of each set screw is provided with a hexagonal opening 303 in the end for receipt of a conventional hexagonal O.D. wrench. The head 303, 305, 307 and 309 of each set screw is accommodated in an orifice 122, 124, 126 and 128 in the circumference of the cylindrical head 102. The orifices or depressions in the head 102 allow the set screw 302, 304, 306 and 308 to be readily seated below the level of the circumference of the cutting head so that the set screws will not snag or catch upon external objects during use.
The shank 106 of the rotatable cutting tool 10 is a conventional round shank which may have a conventional 3/8th inch or 1/2 inch size outside diameter or O.D. for reception into the chuck of a portable drill. Since it is desirable for the sharpening tool to be accommodated in a conventional home drill, the shank should not be too large, since most home drills are no larger than 1/2 or 3/8th inch and, in fact, many are only 1/4 inch capacity. This is an additional reason why it may be undesirable for the head of the tool to be too massive, since instability might be caused if a massive head were accommodated upon a relatively small shank.
The preferred cutting blades 202, 204, 206 and 208 are triangular in shape. At least one edge of each blade is sharpened to a cutting edge which extends into the tapered central opening 104 and accomplishes the actual cutting (FIGS. 2 and 4). A center alignment and attachment hole 222 goes all the way through each cutter blade and provides a means for aligning the blade in proper position within the tool head 102, since the hole 222 aligns with the opposing set screw 302, 304, 306 or 308. The hole 222 preferably extends all the way through the blade. The opposing set screw fits only part way into the hole, at the tapered end portion 302a, 304a, 306a or 308a of the set screw.
As shown in FIGS. 5-7, snowmobile studs come in different configurations 504, 506 and 508. It is within the scope of this invention to provide a device which is capable of sharpening all types of snowmobile studs. The arrangement of the cutting blades 202, 204, 206 and 208 as shown in FIGS. 2, 3 and 4 provides for all of the cutting edges of the blades which extend into the conical opening 104 to form a point at location X (FIG. 4) in order to provide a pointed tip on the snowmobile stud.
It should also be understood that, depending on the angle of inclination of the cutting edge of the blade members, the angle of the conical shape of the stud member will vary. For example, as shown in FIG. 3, the entire outer surface of the stud 500 fits within the angle of inclination of the cutting blades to form a stud 504 similar to that depicted in FIG. 5. A steeper angle of inclination and longer cutting blades will result in a stud 508 having the configuration of that in FIG. 7.
While it is preferred to fit the stud into the conical opening 104 as snugly as possible so that the entire outer surface of the stud 500 is sharpened by the cutting edge of the cutting blade, it is possible with the device of the invention to sharpen only the tip of the stud when the conical opening is positioned over the end of the stud. As shown in the stud 506 of FIG. 6, only the tip 510 of the stud is sharpened by the cutting edges of the cutting blades, and not the entire outer surface of the stud.
As can be seen from the above, the present invention provides a very practical and effective rotating cutting tool for sharpening various elongated objects including, in particular, tread spikes on a snowmobile-type vehicle.
While the invention has been described in considerable detail, in connection with the above drawings and explanations of the various embodiments illustrated, the invention is not to be limited to the particulars of any such embodiments, but is to be construed broadly with reference to the language of the appended claims so as to provide the broadest possible interpretation of such claims in view of the prior art and thereby to effectively encompass the intended scope of the invention.
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A rotatable arbor-type tool for use in a portable power drill is provide for sharpening the ends of metal studs and particularly snowmobile tread studs or spikes. The tool has a cylindrical head with a tapered central opening axially aligned with the axis of rotation of the head. Radial grooves extend from the central opening through the wall of the head to the outer surface thereof. One wall of each groove constitutes an abutment wall against which a preferably triangular cutting blade having a thickness substantially less than the groove width is positioned. The cutting blade is forceably held against the abutment wall by a set screw extending against the cutting blade from the opposite wall leaving an opening extending along the groove past the cutting tool sufficiently wide to provide an exit from the central opening for chips cut from the end of the stud by the cutting edges of the cutting tool. The abutment wall is that wall which faces the direction of rotation of said head. A method of sharpening studs in situ in a snowmobile tread is also provided.
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[0001] The present invention relates to a new β crystalline form of perindopril tert-butylamine salt of formula (I):
BACKGROUND OF THE INVENTION
[0002] Perindopril and its pharmaceutically acceptable salts, and more especially its tert-butylamine salt, have valuable pharmacological properties.
[0003] Their principal property is that of inhibiting angiotensin I converting enzyme (or kininase II), which prevents, on the one hand, conversion of the decapeptide angiotensin I to the octapeptide angiotensin II (a vasoconstrictor) and, on the other hand, degradation of bradykinin (a vasodilator) to an inactive peptide.
[0004] Those two actions contribute to the beneficial effects of perindopril in cardiovascular diseases, more especially in arterial hypertension and heart failure.
[0005] Perindopril, its preparation and its use in therapeutics have been described in European Patent specification EP 0 049 658.
[0006] In view of the pharmaceutical value of this compound, it has been of prime importance to obtain it with excellent purity. It has also been important to be able to synthesise it by means of a process that can readily be converted to the industrial scale, especially in a form that allows rapid filtration and drying. Finally, that form had to be perfectly reproducible, easily formulated and sufficiently stable to allow its storage for long periods without particular requirements for temperature, light, humidity or oxygen level.
DESCRIPTION OF THE PRIOR ART
[0007] The patent specification EP 0 308 341 (equivalent to U.S. Pat. No. 4,914,214, the subject matter of which is hereby incorporated by reference) describes an industrial synthesis process for perindopril. However, that document does not specify the conditions for obtaining perindopril in a form that exhibits those characteristics in a reproducible manner.
[0008] The Applicant has now found that a particular salt of perindopril, the tert-butylamine salt, can be obtained in a well defined, perfectly reproducible crystalline form that especially exhibits valuable characteristics for formulation.
DETAILED DESCRIPTION OF THE INVENTION
[0009] More specifically, the present invention relates to the β crystalline form of the compound of formula (I), characterized by the following powder X-ray diffraction diagram, measured using a Siemens D5005 diffractometer (copper anticathode) and expressed in terms of inter-planar distance d, Bragg's angle 2 theta, intensity and relative intensity (expressed as a percentage of the most intense ray):
Angle 2 theta Inter-planar Relative (°) distance d (Å) Intensity intensity (%) 5.169 17.08 523 16.5 8.379 10.54 1001 31.5 9.350 9.45 3175 100 14.746 6.00 236 7.4 15.411 5.74 753 23.7 15.931 5.56 279 8.8 16.711 5.30 113 3.6 18.161 4.88 122 3.8 20.564 4.32 1198 37.7 21.285 4.17 330 10.4 21.781 4.08 317 10 22.632 3.93 190 6 23.308 3.81 133 4.2 23.797 3.74 427 13.4 24.276 3.66 118 3.7 25.190 3.53 92 2.9 25.924 3.43 251 7.9 26.646 3.34 250 7.9 27.620 3.23 96 3 28.306 3.15 133 4.2
[0010] The invention relates also to a process for the preparation of the β crystalline form of the compound of formula (I), which process is characterized in that:
either, according to a first embodiment, a solution of perindopril tert-butylamine salt in dichloromethane is heated at reflux and is then rapdily cooled to 0° C. and the solid obtained is collected by filtration, or, according to a second embodiment, a solution of perindopril tert-butylamine salt in ethyl acetate is heated at reflux and is then rapidly cooled to 5° C. and the solid obtained is collected by filtration. In the crystallisation process according to the invention it is possible to use the compound of formula (I) obtained by any process. Advantageously, the compound of formula (I) obtained by the preparation process described in patent specification EP 0 308 341 is used. In the first embodiment of the process according to the invention, the concentration of the compound of formula (I) in the dichloromethane is preferably from 100 to 200 g/litre. In the second embodiment of the process according to the invention, the concentration of the compound of formula (I) in the ethyl acetate is preferably from 70 to 90 g/litre.
[0016] The invention relates also to pharmaceutical compositions comprising as active ingredient the β crystalline form of the compound of formula (I) together with one or more appropriate, inert, non-toxic excipients. Among the pharmaceutical compositions according to the invention, there may be mentioned more especially those that are suitable for oral, parenteral (intravenous or subcutaneous) or nasal administration, tablets or dragées, sublingual tablets, gelatin capsules, lozenges, suppositories, creams, ointments, dermal gels, injectable preparations, drinkable suspensions etc.
[0017] The useful dosage can be varied according to the nature and severity of the disorder, the administration route and the age and weight of the patient. It varies from 1 to 500 mg per day in one or more administrations.
[0018] The pharmaceutical compositions according to the invention may also comprise a diuretic such as indapamide.
[0019] The following Examples illustrate the invention but do not limit it in any way.
[0020] The powder X-ray diffraction spectrum was measured under the following experimental conditions:
Siemens D5005 diffractometer, scintillation detector, copper anticathode (λ=1.5405 Å), voltage 40 kV, intensity 40 mA, mounting θ-θ, measurement range: 5° to 30°, increment between each measurement: 0.02°, measurement time per step: 2 s, variable slits : v6, filter Kβ (Ni), no internal reference, zeroing procedure with the Siemens slits, experimental data processed using EVA software (version 5.0).
EXAMPLE 1
β crystalline form of perindopril tert-butylamine salt
[0032] 135 g of perindopril tert-butylamine salt obtained according to the process described in patent specification EP 0 308 341 are dissolved in 1100 ml of dichloromethane heated at reflux.
[0033] The solution is then cooled to 0° C. and the solid obtained is collected by filtration.
[0000] Powder X-ray Diffraction Diagram:
[0034] The powder X-ray diffraction profile (diffraction angles) of the β form of perindopril tert-butylamine salt is given by the significant rays collated in the following table together with the intensity and relative intensity (expressed as a percentage of the most intense ray):
Angle 2 Inter-planar Relative theta (°) distance d (Å) Intensity intensity (%) 5.169 17.08 523 16.5 8.379 10.54 1001 31.5 9.350 9.45 3175 100 14.746 6.00 236 7.4 15.411 5.74 753 23.7 15.931 5.56 279 8.8 16.711 5.30 113 3.6 18.161 4.88 122 3.8 20.564 4.32 1198 37.7 21.285 4.17 330 10.4 21.781 4.08 317 10 22.632 3.93 190 6 23.308 3.81 133 4.2 23.797 3.74 427 13.4 24.276 3.66 118 3.7 25.190 3.53 92 2.9 25.924 3.43 251 7.9 26.646 3.34 250 7.9 27.620 3.23 96 3 28.306 3.15 133 4.2
EXAMPLE 2
β crystalline form of perindopril tert-butylamine salt
[0035] 125 g of perindopril tert-butylamine salt obtained according to the process described in patent specification EP 0 308 341 are dissolved in 1.5 litres of ethyl acetate heated at reflux.
[0036] The solution is then cooled rapidly to 5° C. and the solid obtained is collected by filtration.
EXAMPLE 3
Pharmaceutical Composition
[0037] Preparation formula for 1000 tablets each containing 4 mg of active ingredient:
Compound of Example 1 4 g Hydroxypropylcellulose 2 g Wheat starch 10 g Lactose 100 g Magnesium stearate 3 g Talc 3 g
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A β crystalline form of the compound of formula (I):
characterized by its powder X-ray diffraction data. Medicinal products containing the same which are useful as inhibitors of angiotensin I converting enzyme.
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CROSS-REFERENCE TO RELATED APPLICATION
[0001] This application claims the priority benefit of Taiwan application serial no. 89124860, filed Nov. 23, 2000.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] The invention relates in general to a voltage stabilizer. More particularly, the invention relates to a voltage stabilizer of an embedded flash memory.
[0004] 2. Description of the Related Art
[0005] During the access of a flash memory, methods to indicate high threshold voltage and low threshold voltage are different. In one conventional method, a reference memory cell near a bit line voltage is compared with a selected memory cell. As shown in FIG. 1, a structure to compare the reference memory cell with the selected memory cell is illustrated. The structure comprises a bit line decoder 10 , a word line decoder 12 , a memory cell 14 , a current-to-voltage converter 16 , a reference word line 18 , a reference memory cell 20 , a reference voltage 22 and a voltage sense amplifier 24 .
[0006] An output of the bit line decoder 10 is coupled to a drain of the memory cell 14 . An output of the word line decoder 12 is coupled to a gate of the memory cell 14 . A source of the memory cell 14 is coupled to a ground voltage Vss. The output of the bit line decoder 10 is further coupled to the current-to-voltage converter 16 . A gate of the reference memory cell 20 at the other side is coupled to the reference word line 18 . A drain of the reference memory cell 20 is coupled to another bit line decoder (not shown), and a source thereof is coupled to the ground voltage Vss. A drain of the reference memory cell 20 is coupled to the reference voltage 22 . That is, both the drain of the reference memory cell 22 and the current-to-voltage converter 16 are coupled to the voltage sense amplifier 24 .
[0007] The above structure is used to detect the Vt distribution of memory cells on a chip, so as to trace the problems in fabrication process and to maintain a correct access. However, the structure is restricted by the variation range of the VDD. When the variation of the VDD exceeds ±10%, the word line voltage dependent on the VDD has a significant variation. Thus, the reference voltage bias node applied to the voltage sense amplifier 24 is shifted to cause an error access.
SUMMARY OF THE INVENTION
[0008] The invention provides a voltage stabilizer of an embedded flash memory. After receiving and processing an input voltage, a fixed voltage is output.
[0009] The stabilizer of the embedded flash memory comprises a voltage inspector, an annular oscillator, a frequency band interstitial voltage and stabilized clock generator, a switching controller, a charge pump, an NMOS transistor, a first resistor, a second resistor, a comparator, a PMOS transistor, a first capacitor and a second capacitor.
[0010] The voltage inspector receives a voltage to perform a range inspection, so as to select a value higher or lower than a standard value. When the value is higher than the standard value, the input voltage is output from a first output terminal. When the value is lower than the standard value, the input voltage is output from a second output terminal.
[0011] The annular oscillator generates a clock signal. The frequency band interstitial voltage and stabilized clock generator is coupled to the annular oscillator and the voltage inspector to generate a stabilized clock signal after receiving the clock signal, and to output a frequency band interstitial voltage to the voltage inspector as a power supply.
[0012] The switching controller is coupled to the first output terminal of the voltage inspector. When a voltage is input, the switching controller is conducted to output the fixed voltage to the final output terminal. The charge pump is coupled to the second output terminal of the voltage inspector, the frequency band interstitial voltage and stabilized clock generator to receive the stabilized clock signal. When the input voltage is lower than the standard value, the input voltage is received and charged to a fixed voltage. The fixed voltage is output from the output terminal.
[0013] The NMOS transistor has a gate coupled to the second output terminal of the voltage inspector to receive the input voltage and a source coupled to the ground voltage. The first resistor has one terminal coupled to a drain of the NMOS transistor, and the other terminal coupled to one terminal of the second resistor. The other terminal of the second resistor is coupled to the final output terminal. The comparator comprises a first input terminal, a second input terminal, a third input terminal and an output terminal. The first input terminal is to receive the frequency band interstitial voltage, the second input terminal is coupled between the first and the second resistors, and the third input terminal is coupled to an output terminal of the charge pump to control the operation of the comparator. A gate of the PMOS transistor is coupled to the output terminal of the comparator. A source of the PMOS transistor is coupled to the output terminal of the charge pump. A drain of the PMOS transistor is coupled to the final output terminal. The first capacitor C 1 is coupled between the source of the PMOS transistor and the ground voltage. The second capacitor C 2 is coupled between the final output terminal and the ground voltage.
[0014] The frequency band interstitial voltage is 1.25 V. The resistance ratio of the first resistor R 1 and the second resistor R 2 is 1:3.
[0015] 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 DRAWINGS
[0016] [0016]FIG. 1 shows a conventional structure to compare a reference memory cell near a bit line voltage with a selected memory cell;
[0017] [0017]FIG. 2 shows an embodiment of a VCC 5 stabilizer of an embedded flash memory to provide a power source for a word line decoder; and
[0018] [0018]FIG. 3 shows the application of the stabilizer of the embedded flash memory to the bit line of a selected memory cell.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0019] As mentioned above, as the embedded flash memory is restricted by the variation limit of VDD±10%, the bias node of the voltage sense amplifier 24 is shifted to cause error access. Therefore, in the invention, a voltage stabilizer of the embedded flash memory is designed to generate a fixed voltage range as shown in FIG. 2. The structures which have been illustrated in FIG. 1 are not repeated here. In FIG. 2, the VCC 5 stabilized voltage generator 25 , that is, the voltage stabilizer of the embedded flash memory provided by the invention, and the potential shifter 26 are added. As the VCC 5 generator 25 constantly generates a fixed voltage VCC 5 to the potential shifter 26 , accompanied by the output voltage of the word line decoder 27 , the low voltage is directly output from the potential shifter 26 to the gate of the memory cell 28 . Similarly, as the VCC 5 generator 25 generates the fixed voltage VCC 5 , the high voltage is output from the potential shifter 26 to the gate of the memory cell 28 .
[0020] Referring to FIG. 2 and FIG. 3, a detailed description of the fixed voltage VCC 5 generated by the VCC 5 generator 25 , that is, the stabilizer of the embedded flash memory, is given as follows.
[0021] The stabilizer of the embedded flash memory comprises a voltage inspector 30 , an annular oscillator 32 , a frequency band interstitial voltage and stabilized clock generator 34 , a switching controller 36 , a charge pump 38 , an NMOS transistor 40 , a first resistor 42 , a second resistor 44 , a comparator 46 , a PMOS transistor 48 , a first capacitor 50 and a second capacitor 52 .
[0022] During the operation, an input voltage VDD with a wide variation range (for example, ranging from about 2.4 V to about 5.5 V) is input to the voltage inspector 30 . A voltage range inspection is performed with a determined standard value (for example, 4.5 V in this embodiment). When the input voltage VDD is higher than the standard value, that is, 5.5≧VDD≧4.5, the input voltage VDD is referred as a normal voltage and output from a first output terminal 54 of the voltage inspector 30 . When the input voltage VDD is lower than the standard value, that is 4.5≧VDD≧2.4, the input voltage is referred as a low voltage and output from a second output terminal 56 of the voltage inspector 30 . Meanwhile, the annular oscillator 32 generates a clock signal Clock to the frequency band interstitial voltage and stabilized clock generator 34 which is coupled to the annular oscillator 32 . After receiving the clock signal Clock, a stabilized clock signal CLK 25 is generated and connected to the voltage inspector 30 to provide a frequency band interstitial voltage Vbg as a power source. The frequency band interstitial voltage Vbg is fixed as 1.25.
[0023] When the input voltage VDD is lower than 5.5 V and higher than 4.5 V, the input voltage VDD is output from the first output terminal 54 to the switching controller 36 . The switching controller 36 is thus conducted to directly output a fixed voltage Vc to a final output terminal VCC 5 . When the input voltage VDD is lower than 4.5 V and higher than 2.4 V, the input voltage VDD is output to the charge pump 38 . With the operation of the stabilized clock signal CLK 25 input from the frequency band interstitial voltage clock generator 34 , the input voltage VDD lower than 4.5 V is charged to a sufficient high voltage (larger than 5 V). A fixed voltage VCC 5 of about 4.75 V±5% is output from the output terminal 60 . In this embodiment, the fixed voltage has a stablized range between about 2.4 V and about 5.6 V and the variation according to temperature is about 50 ppm/° C.
[0024] In addition, the gate of the NMOS transistor 40 also receives the input voltage VDD output from the second output terminal 56 of the voltage inspector 30 . The source of the NMOS transistor 40 is coupled to a ground voltage, and a drain of the NMOS transistor 40 coupled to one terminal of the first resistor (R 1 ) 42 that has the other terminal coupled to one terminal of the second resistor (R 2 ) 44 . The other terminal of the second resistor 44 is coupled to a final output terminal VCC 5 . The above first resistor (R 1 ) 42 and the second resistor (R 2 ) 44 are 1:3.
[0025] The comparator 46 comprises a first input terminal 62 to receive the frequency band interstitial voltage Vbg, a second input terminal 64 coupled between the first and the second resistors 42 and 44 , and a third input terminal 66 coupled to an output terminal 60 of the charge pump 38 . A gate of the PMOS transistor 48 is coupled to the output terminal 68 of the comparator 46 . A drain of the PMOS transistor 48 is coupled to the output terminal 60 of the charge pump 38 . A source of the PMOS transistor 48 is coupled to the final output terminal VCC 5 . The first capacitor 50 is coupled between the source of the PMOS transistor 48 and the ground voltage. The second capacitor 52 is coupled between the final output terminal VCC 5 and the ground voltage.
[0026] When the input voltage VDD is lower than 4.5 V and higher than 2.4 V, the high voltage output from the output terminal 60 of the charge pump 38 is a power supply for operation of the comparator 46 . Meanwhile, the input voltage VDD is fed into the gate of the NMOS transistor 40 to conduct the NMOS transistor 40 . The second capacitor 52 is charged to the fixed voltage Vc (about 4.75 V). When the voltage VCC 5 is too low (<4.5 V), the discharge is performed from the second resistor (R 2 ) 44 and the first resistor (RI) 42 . The voltage at the second output terminal 64 between the first resistor 42 and the second resistor 44 is lower then 1.2 V. The frequency band interstitial voltage Vbg is fixed as 1.25 V. The output of the comparator 46 is maintained at “0”. As a result, the PMOS transistor 48 is conducted. The output voltage of the output terminal 60 of the charge pump 38 is pulled up and output to the final terminal VCC 5 . When the voltage VCC 5 is high (>4.75 V), the second output terminal 64 has a voltage higher than 1.2 V. The output of the comparator 46 is “1”. As a result, the PMOS transistor 48 is turned off. The charging process to the capacitor C 2 is stopped. Therefore, the voltage VCC 5 is maintained at the fixed voltage (about 4.75 V±5%). If the input voltage is raised to higher than the normal voltage 4.5 V, the second output terminal 56 stops outputting the input voltage, so that the NMOS transistor 40 can not be conducted, and the input voltage is not supplied to the charge pump 38 for operation. The above process is no longer performed. In contrast, the process is performed via the first terminal 54 . The voltage VCC 5 is directly supplied by the fixed voltage Vc to save power consumption when the normal voltage source is not operating.
[0027] In the above voltage stabilizer of the embedded flash memory, the VDD with a large variation is output within a fixed voltage range, according to whether it is lower or higher than a fixed voltage. To further depict the invention, a description, FIG. 2, combining the voltage stabilizer of the embedded flash memory with the structure as shown in FIG. 1 is given here. The difference between FIG. 1 and FIG. 2 is the addition of the VCC 5 generator 25 and the potential shifter 26 . Since the VCC 5 generator 25 constantly generates a fixed voltage to the potential shifter 26 , the word line decoder 27 outputs a voltage (low voltage 0 and high voltage VDD). The low voltage 0 is directly output from the potential shifter 26 to the gate of the memory cell 28 . The high voltage is the Voltage VCC 5 generated by the VCC 5 generator and is output from the potential shifter 26 to the gate of the memory cell 28 .
[0028] According to the above, the voltage stabilizer of the embedded flash memory modulates a voltage VDD with a significant variation to a fixed voltage to be output. The voltage received at the bit line is thus fixed to avoid error access.
[0029] Other embodiments of the invention will appear to those skilled in the art from consideration of the specification and practice of the invention disclosed herein. It is intended that the specification and examples be considered as exemplary only, with a true scope and spirit of the invention being indicated by the following claims.
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A voltage stabilizer of an embedded flash memory to modulate an input voltage VDD with a wide range of variation to a fixed voltage as an output. The voltage at the bit line of the selected memory cell can be fixed to avoid error access. The voltage stablizer of the embedded flash memory performs a voltage range inspection using a voltage inspector. Comparing to a standard value, an input voltage higher or lower than the standard value is output from a first terminal or a second terminal, respectively. The input voltage output from the first or second terminals is then stabilized to output a fixed voltage.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to an improved method and apparatus for drilling a well beneath a body of water. More particularly, the invention relates to a method and apparatus for maintaining a controlled hydrostatic pressure in a drilling riser.
2. Description of the Prior Art
In recent years the search for oil and natural gas has extended into deep waters overlying the continental shelves. In deep waters it is common practice to conduct drilling operations from floating vessels or from tall bottom-supported platforms. The floating vessel or platform is stationed over a wellsite and is equipped with a drill rig and associated equipment. To conduct drilling operations from a floating vessel or platform a large diameter riser pipe is employed which extends from the surface down to a subsea wellhead on the ocean floor. The drill string extends through the riser into blowout preventers positioned atop the wellhead. The riser pipe serves to guide the drill string and to provide a return conduit for circulating drilling fluids.
An important function performed by the drilling fluids is well control. The column of drilling fluid contained within the wellbore and the riser pipe exerts hydrostatic pressure on the subsurface formations which overcomes formation pressures and prevents the influx of formation fluids. However, if the column of drilling fluid exerts excessive hydrostatic pressure, the reverse problem can occur, i.e., the pressure of the fluid can exceed the natural pressure of one or more of the formations. Should this occur, the hydrostatic pressure of the drilling fluid could initiate and propogate a fracture in the formation, resulting in fluid loss to the formation, a condition known as "lost circulation". Excessive fluid loss to one formation can result in loss of well control in other formations being drilled, thereby greatly increasing the risk of a blowout.
The problem of lost circulation is particularly troublesome in deep waters where the fracture pressure of shallow formations, especially weakly consolidated sedimentary formations, does not significantly exceed that of the overlying column of seawater. A column of drilling fluid, normally weighted by drill cuttings and various additives such as bentonite, need be only slightly more dense than seawater to exceed the fracture pressure of these formations. Therefore, to minimize the possibility of lost circulation caused by formation fracture while maintaining adequate well control, it is necessary to control the hydrostatic pressure within the riser pipe.
There have been various approaches to controlling the hydrostatic pressure of the returning drilling fluid. One approach is to reduce the drill cuttings content of the drilling fluid in order to decrease the density of the drilling fluid. That has been done by increasing drilling fluid circulation rates or decreasing drill bit penetration rates. Each of these techniques is subject to certain difficulties. Decreasing the penetration rate requires additional expensive rig time to complete the drilling operation. This is particularly a problem offshore where drilling costs are several times more expensive than onshore. Increasing the circulation rate is also an undesirable approach since increased circulation requires additional pumping capacity and may lead to erosion of the well-bore.
Another approach in controlling hydrostatic pressure is to inject gas into the lower end of the riser. Gas injected into the riser intermingles with the returning drilling fluid and reduces the density of the fluid. An example of a gas injection system is disclosed in U.S. Pat. No. 3,815,673 (Bruce et al) wherein an inert gas is compressed, transmitted down a separate conduit, and injected at various points along the lower end of the drilling riser. The patent also discloses a control system responsive to the hydrostatic head of the drilling fluid which controls the rate of gas injection in the riser in order to maintain the hydrostatic pressure at a desired level. Such control systems, however, have the disadvantage of inherent time lags which can result in instability. This is especially a problem in very deep water where there may be significant delays from the time a control signal is initiated to the time a change in gas rate can produce a change in the pressure at the lower end of the riser pipe. As a result, the gas lift systems disclosed in the prior art do not have predictable responses with changing conditions.
SUMMARY OF THE INVENTION
The apparatus and method of the present invention permit control of the pressure of drilling fluid during offshore drilling operations. In accordance with the present invention, gas is injected into a drilling riser to provide the lift necessary to bring the drilling fluid to the surface and to reduce the density of the drilling fluid. The rate of gas injection is maintained so that the pressure of the drilling fluid at the bottom of the riser would be less than the hydrostatic pressure of the surrounding seawater if the drilling fluid were isolated from the seawater. However, seawater is permitted to flow into the lower end of the riser in response to the differential pressure between the drilling fluid and the seawater so that the hydrostatic pressures of the drilling fluid and the seawater become approximately equalized.
The apparatus of the present invention includes conventional offshore drilling components such as a riser pipe extending from a floating drilling vessel or platform to a subsea wellhead and a drill string extending through the riser pipe and into the borehole penetrating subterranean formations. Gas injection means such as gas supply conduits or injection lines are provided for introducing gas into the riser pipe. Valve means, such as a check valve, are positioned near the lower end of the riser to permit entry of seawater into the riser pipe. The apparatus can also include control means for regulating the rate of gas injection and the influx of seawater. Preferably, the drilling fluid used in the present invention is seawater or a saline drilling mud.
In accordance with the method of the present invention, a gas is injected into the riser pipe to intermingle and mix with the drilling fluid so that the density of the drilling fluid is sufficiently reduced to cause it to be positively displaced or "lifted" to the surface. The drilling fluid is slightly overlifted so that there exists a pressure differential between the drilling fluid within the riser and the surrounding body of seawater. Seawater is permitted to enter the lower end of the riser thereby reducing the pressure differential and approximately equalizing the pressure of the drilling fluid and the seawater. As a result, the pressure of the drilling fluid in the wellbore automatically stabilizes at a level which is below the fracture pressure of the surrounding formations. The system resists destabilization because the rate of influx of seawater automatically responds to changes in the density and circulating rate of the drilling fluid. Consequently, sophisticated control systems are not needed with the present invention.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an elevation view, partially in section, of a floating drilling vessel provided with the apparatus of the present invention.
FIGS. 2(A) and 2(B) are plots of pressure versus depth which illustrate and compare the performance of the present invention with conventional drilling practices.
FIG. 3 is a schematic diagram, partially in section, of the apparatus of the present invention including a control system for regulating the hydrostatic pressure of the drilling fluid in a marine riser.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows a drilling vessel 10 floating on a body of water 13 and equipped with apparatus of the present invention to carry out the method of the present invention. A wellhead 15 is positioned on sea floor 17 which defines the upper surface or "mudline" of sedimentary formation 18. A drill string 19 and associated drill bit 20 are suspended from derrick 21 mounted on the vessel and extends to the bottom of wellbore 22. A length of structural casing pipe 26 extends from the wellhead to a depth of a few hundred feet into the sediments above wellbore 22. Concentrically receiving drill string 19 is riser pipe 23 which is positioned between the upper end of blowout preventer stack 24 and vessel 10. Located at each end of riser pipe 23 are ball joints 25.
Situated aboard vessel 10 is compressor 27 which provides high pressure gas for gas injection line 28. Injection line 28 extends from compressor 27 down part of the length of the riser and into riser pipe 23. Located at the lower end of riser pipe 23, above lower ball joint 25, is inlet 31 which permits entry of seawater into the riser pipe. The inlet can also be located on blowout preventer stack 24. Controlling the entry of seawater and preventing escape of drilling fluid from the riser is check valve 32
In order to control the pressure of the drilling fluid within riser pipe 23 compressed air is directed from compressor 27 through gas injection line 28 into the riser. The injected gas mixes with the drilling fluid to form a lightened three phase fluid consisting of gas, drilling fluids and drill cuttings. The gasified fluid has a density substantially less than the original drilling fluid and therefore exerts a lower hydrostatic pressure on sedimentary formation 18. The gas also provides lift to the drilling fluid and assists in returning it up through the riser to surface vessel 10.
Ideally, the density of the drilling fluid should be approximately the same as the surrounding sea water. Normally, density control is difficult to achieve and usually requires a control system which closely regulates the rate of gas injection and the circulatiion of drilling fluid. The present invention, however, provides a simple control system utilizing external sea water as a pressure balancing fluid that gives almost instantaneous control.
For most drilling operations, seawater can be used as the drilling fluid through approximately the first few thousand feet of rock. Conventional "mud" based drilling fluids are needed only at greater depths where the well control provided by weighted drilling muds are necessary. Therefore, in drilling through shallow formations a seawater based drilling fluid can be used. Obviously, diluting such a drilling fluid with sea water from outside the riser presents no problem.
In the present invention check valve 32 is opened, permitting the influx of seawater into riser pipe 23. If the drilling fluid in the riser pipe is slightly overlifted by injecting more gas than is necessary to return the drilling fluid to the surface there will be a net pressure differential between the drilling fluid and surrounding seawater. This pressure differential will register across valve 32 and will draw seawater into the riser pipe through inlet 31. If valve 32 and inlet line 31 are sufficiently large the pressure differential will tend to decrease until the pressure within the riser and the pressure of the seawater substantially equalize. The system will tend to be self controlling, that is, the flow of seawater into the riser will automatically adjust to compensate for changes in the rate of gas injection, density of the drilling fluid, or circulation rate of the drilling fluid, thereby maintaining the hydrostatic pressure inside the riser pipe almost equal to the pressure of the surrounding seawater. The system is therefore self stabilizing. However, in the event the pressure within the riser exceeds the external pressure of the surrounding seawater, check valve 31 will prevent reverse flow of drilling fluid into the sea, thereby preventing any contamination of the sea with drill cuttings or mud additives.
The avoidance of formation fracture by the method and apparatus of the present invention is illustrated in FIGS. 2(A) and 2(B) which compares the pressure relationships involved in drilling an offshore well with and without the present invention. In FIG. 2(A), curve A relates hydrostatic pressure versus depth for seawater having a pressure gradient of 0.444 psi/ft (or about 8.5 pounds per gallon). This curve is shown extending from the sea surface to the sea floor or mudline which has arbitrarily been chosen to be 6000 feet below the surface. Extending below the sea floor is curve B which represents the fracture pressure of the subterranean formations beneath the sea. For normally consolidated sediments, the fracture pressure is approximately equal to the seawater pressure at the sea floor and increases with depth below the sea floor at a gradient greater than that of seawater (the seawater gradient being shown by the dotted line extension of curve A).
Corresponding to curves A and B is curve C which relates hydrostatic pressure versus depth for drilling mud inside a riser pipe and wellbore. The curve is for a typical drilling mud having a density of 9.5 pounds per gallon (including drill cuttings) thereby giving it a pressure gradient of 0.494 psi/ft. It can be readily seen that until a total depth of about 7700 feet (1700 feet below the sea floor) the hydrostatic wellbore pressure of the drilling mud exceeds the fracture pressure of the formation. The point of intersection of curves B and C represents the point below which the formation can be safely drilled with the 9.5 ppg mud. However, except for the first few hundred feet below the mudline which are protected by structural casing, the entire interval from beneath the structural casing to a depth of 1700 feet below the sea floor would be in danger of formation fracture and lost returns and could not be safely drilled with conventional drilling practices using 9.5 pound per gallon mud.
FIG. 2(B) shows how the present invention permits safe drilling through upper level sediments without the danger of formation fracture. As before, curves A and B respectively represent seawater pressure and fracture pressure versus depth. Curve C' represents the hydrostatic pressure profile of the drilling fluid in the riser pipe and wellbore. Curve C' is nonlinear and basically consists of three separate segments which are labeled D, E and F.
As indicated, gas is injected into the riser pipe at a depth of about 2000 feet. Segment D of Curve C' represents the pressure profile of the fluid in the riser above the point of gas injection, the fluid consisting of a mixture of drilling mud, sea water and gas. The gas injected into the fluid substantially reduces the density of the fluid, thereby shifting the pressure profile to the left of the sea water profile (Curve A). The fluid in the riser is thus gas lifted to the surface from a depth of 2000 feet where it is discharged to a separator at some positive pressure.
Segment E of Curve C' is the pressure profile from below the point of gas injection to the sea floor. The fluid in the riser at this point consists of a mixture of drilling mud (9.5 ppg) and seawater (8.5 ppg), the seawater coming in as a result of the influx into the riser across the check valve positioned at the lower end of the riser. The influx of seawater not only stabilizes the system, but also reduces the overall density of the fluid in the riser. Consequently, Curve C' slopes more steeply than Curve C in FIG. 2(A).
Segment F of Curve C' represents the pressure profile of the drilling mud in the borehole. It has a slope slightly less steep than segment E since the drilling mud at this point has not been mixed with lower density seawater. However, the gas injection and seawater influx offsets the riser and wellbore pressure sufficiently so that at the depth of the sea floor the mud pressure is approximately equal to that of the surrounding seawater. Therefore, the pressure of the mud within the wellbore will always be (as shown in FIG. 2(B)) less than the fracture pressure of the formation.
FIG. 3 schematically depicts in more detail the gas lift system of the present invention and a simplified control design that can be used with the lift system. Gas after being routed through a gas treater 35 is fed into compressor 27. The gas used can be air or an inert gas. If it is desirable to minimize the chance of corroding valves or tubulars coming in contact with the gas, an inert gas such as nitrogen is preferred. A frequently used inert gas is the exhaust gas generated by the internal combustion engines aboard the drill ship which provide the power to run the equipment associated with drilling operations. Normally, the gas undergoes several treatment stages before being sent to compressor 27.
Drilling fluid (preferably seawater) is circulated downwardly through drill pipe 19 and returns through riser pipe 23. Compressed gas injected into the riser pipe mixes with the drilling fluid and drill cuttings to form a lightened fluid indicated by numeral 40. The lightened drilling fluid flows upwardly to rotating drilling head 41 which diverts the gas-liquid mixture away from the drill floor. Both gas and drilling fluid are diverted into separator 42 where the gas constituents are removed from the drilling fluid. The drilling fluid may then be treated by a conventional mud treatment system to remove drill cuttings. If preferred, both drilling fluid and gas can be recycled into the system once separated.
As noted prevously, the degree of control over the lift system of the present invention is maximized (while minimizing complexity) by the influx of seawater through inlet 31. With a constant overlift being provided by gas injection line 28, there will be a continuous flow of seawater into riser pipe 23 through check valve 32. The rate of flow of seawater into the riser will automatically compensate for changes in drilling fluid density and circulating rate provided drilling fluid is being sufficiently overlifted to reduce the pressure of the drilling fluid to below that of the surrounding seawater. Nevertheless, it is desirable that influx of seawater be minimized since a volume of drilling fluid equal to the volume of sea water entering the riser must be discharged at the surface.
As shown in FIG. 3, control over seawater influx can be maintained by a simple control loop. Flowmeter 51 measures the rate at which sea water enters riser pipe 23 from valve 32 and transmits a flow signal by means of electrical conductor 52 to controller 46. Controller 46 returns a control signal, responsive to the flow signal, to adjust the gas output of compressor 27. The rate of gas injection could then be altered to keep the degree of gas lift to a level which provides a positive, yet low, influx of seawater through check valve 32. The monitoring of seawater influx also provides a useful indication of well kicks or lost circulation. Changes in drilling fluid circulation rate due to kicks or lost circulation would be reflected by approximately equal and opposite changes in seawater influx thereby giving a timely warning of well control problems.
Seawater influx provided by the present invention is also useful in maintaining well control when drilling fluid circulation must be stopped. For example, when it is necessary to stop fluid circulation for a few minutes to connect a new joint of drill pipe, seawater influx will automatically increase to compensate for the cessation of flow of drilling fluid. In this manner circulation can be maintained through the riser pipe thus avoiding momentary interruption of the gas lift system and insuring a quick return to steady state operations once drilling fluid circulation resumes.
It should be apparent from the foregoing that the apparatus and method of the present invention offer significant advantages over pressure control systems for marine risers previously known to the art. It will be appreciated that while the present invention has been primarily described with regard to the foregoing embodiments, it should be understood that several variations and modifications may be made in the embodiments described herein without departing from the broad inventive concept disclosed herein.
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An improved offshore drilling method and apparatus are disclosed which are useful in preventing formation fracture caused by excessive hydrostatic pressure in a drilling riser. Gas is injected into the riser to provide the lift necessary to return the drilling fluid to the surface and to reduce the density of the drilling fluid. The rate of gas injection overlifts the drilling fluid to the extent that the pressure of the fluid is reduced to less than that of the seawater surrounding the riser. Seawater is permitted to flow into the lower end of the riser in response to the differential pressure between the drilling fluid and seawater so that the pressures of the drilling fluid and the seawater approximately equalize.
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BACKGROUND AND SUMMARY OF THE INVENTION
The present invention relates generally to speech recognition systems. More particularly, the invention relates to speech model adaptation in a supervised system employing a corrective adaptation procedure that weights correct and incorrect models by a log likelihood ratio between current and best hypotheses.
Speech recognizers in popular use today employ speech models that contain data derived from training speakers. In many cases, training speech from these speakers is collected in advance and used to generate speaker independent models representing a cross section of the training speaker population. Later, when the speech recognizer is used, data extracted from speech of a new speaker is compared with the speaker independent models and the recognizer identifies the words in its lexicon that represent the best match between the new speech and the existing speech models.
If the new speaker's speech patterns are sufficiently similar to those of the training population, then the recognizer will do a reasonably good job of recognizing the new speaker's speech. However, if the new speaker has a strong regional accent or other speech idiosyncrasies that are not reflected in the training population, then recognition accuracy fails off significantly.
To enhance the reliability of the speech recognizer, many recognition systems implement an adaptation process whereby adaptation speech is provided by the new speaker, and that adaptation speech is used to adjust the speech model parameters so that they more closely represent the speech of the new speaker. Some systems require a significant quantity of adaptation speech. New speakers are instructed to read long passages of text, so that the adaptation system can extract the necessary adaptation data to adapt the speech models.
Where the content of the adaptation speech is known in advance, the adaptation system is referred to as performing “supervised” adaptation. Where the content of the adaptation speech is not known in advance, the adaptation process is referred to as “unsupervised” adaptation. In general, supervised adaptation will provide better results than unsupervised adaptation. Supervised techniques are based on the knowledge of the adaptation data transcriptions, whereas unsupervised techniques determine the transcriptions of the adaptation data automatically, using the best models available, and consequently provide often limited improvements as compared to supervised techniques.
Among the techniques available to perform adaptation, transformation-based adaptation (e.g., Maximum Likelihood Linear Regression or MLLR) and Bayesian techniques (e.g., Maximum A Posteriori or MAP) adaptation are most popular. While transformation-based adaptation provides a solution for dealing with unseen models, Bayesian adaptation uses a priori information from speaker independent models. Bayesian techniques are particularly useful in dealing with problems posed by sparse data. In practical applications, depending on the amount of adaptation available, transformation-based, Bayesian techniques or a combination of both may be chosen.
Given a small amount of adaptation data, one of the common challenges of supervised adaptation is to provide adapted models that accurately match a user's speaking characteristics and are discriminative. On the other hand, unsupervised adaptation has to deal with inaccuracy of the transcriptions and the selection of reliable information to perform adaptation. For both sets of techniques it is important to adjust the adaptation procedure to the amount of adaptation data available.
The present invention addresses the foregoing issue by providing a corrective adaptation procedure that employs discriminative training. The technique pushes incorrect models away from the correct model, rendering the recognition system more discriminative for the new speakers speaking characteristics. The corrective adaptation procedure will work with essentially any adaptation technique, including transformation-based adaptation techniques and Bayesian adaptation techniques, and others.
The corrective adaptation procedure of the invention weights correct and incorrect speech models by a log likelihood ratio between the current model and the best hypothesis model. The system generates a set of N-best models and then analyzes these models to generate the log likelihood ratios. Because supervised adaptation is performed, and the correct label sequence is known, the N-best information is exploited by the system in a discriminative way. In the preferred system a positive weight is applied to the correct label and a negative weight is applied to all other labels.
In comparison with other discriminative methods, the corrective adaptation technique of the invention has several advantages. It is computationally inexpensive, and it is easy to implement. Moreover, the technique carries out discrimination that is specific to a given speaker, such that convergence is not an issue.
For a more complete understanding of the invention, its objects and advantages, refer to the following specification and to the accompanying drawings. dr
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a block diagram illustrating the adaptation system of the invention in its single-pass form;
FIG. 2 is a block diagram of the adaptation system illustrating how a multiple pass system may be implemented using iteration;
FIG. 3 is a flowchart diagram illustrating the corrective N-best decoding process of the invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
The present adaptation system will work with a variety of different speech recognizer implementations. Thus, for illustration purposes, a model-based recognizer is illustrated at 10 in FIG. 1 . Recognizer 10 operates in conjunction with a set of speech models 12 . These models are supplied in an initial form, typically a speaker-independent form. The adaptation system adapts these models based on supervised adaptation data supplied as input by the new speaker. Although there are a variety of different ways to model acoustic sounds, many recognizers in popular use today employ Hidden Markov Models to represent each of the sound units (e.g., words) within the recognizer's lexicon.
In most recognition applications the recognizer is designed to select the best solution, that is, the model that best corresponds to the input utterance. However, in this application the recognizer supplies the N-best solutions 14 , that is, a predetermined fixed plural number of solutions or, alternatively, a plural number of solutions that had a recognition score greater than a predetermined threshold. In either case, recognizer 10 generates a score for each speech model, indicating the likelihood that the given model generated the input utterance. The likelihood score is used in a conventional recognizer to select the single best solution. In the present adaptation system, the N-best likelihood scores are used to generate a list of N-best solutions 14 .
Because the adaptation data is provided under supervised conditions (the adaptation speech corresponds to words that are expected by the recognizer) it is possible to perform forced alignment of the input adaptation data with the correct label sequence. The adaptation system then processes these segments in an N-best pass to collect the N-most probable labels. These N-best labels are then used to adapt the speech models 12 , by applying either a positive weight or a negative weight according to the following rule: Equation 1: φ n = { κ , if correct label - ρ ( [ L n - L 1 ] η ) , otherwise }
In the above equations κ represents the weight given to the supervised forced alignment. It is independent of n because we want to recover the correct label the same way whatever its rank is. L n is the likelihood of the Nth-best answer. Components ρ and η control the amount of backoff that misrecognized letters receive. Ensuring that η>0 and κ>(N−1)ρ guarantees that for a given segment, the sum of all weights will be positive, assuming the correct label is among the N-best solutions 14 . Typical values for these parameters are: κ=2, η=00.1 and ρ=0.3.
The embodiment illustrated in FIG. 1 represents a single pass application of the corrective N-best decoding scheme of the invention. Iterative procedures can also be employed over the adaptation data to further improve the speech models. An iterative embodiment is illustrated in FIG. 2 and will be described more fully below.
The assigning of weights to the N-best transcriptions corresponding to their likelihoods, produces a natural information extraction and data corrective process. Reliable information corresponding to correct labels becomes enhanced by the positive weight applied. Unreliable information is correspondingly diminished in importance because of the negative weight applied. The system thus tends to push models that generate incorrect labels away from those that generate correct ones. In the preferred embodiment the system is designed such that the sum of all weights applied are positive. Doing so causes the system to converge upon an optimal adaptation solution. Were the negative weights allowed to outweigh the positive one, then the adaptation solution could, under some circumstances, diverge. This would result in an adaptation scheme that might degrade rather than improve recognition performance.
Once weights are applied to the N-best solutions as illustrated diagrammatically at 16 in FIG. 1, the weighted information is then used by the model adaptation module 18 to selectively adapt the speech models 12 . In the presently preferred embodiment, model information is accumulated among the N-best transcriptions for the entire set of sentences and then used to adapt the speech models at the conclusion of the set. Altematively, model adaptation may be performed on each sentence or even each individual word separately within a sentence.
The manner in which adaptation is performed will depend upon the adaptation technique selected. If the adaptation technique is a transformation-based technique such as MLLR, equation 2 is used to transform the mean vectors.
{circumflex over (μ)}=Wμ+b, Equation 2
In the above equation where {circumflex over (μ)} and μ are respectively the adapted and original mean vector; W and b are the transformation matrix and bias derived to optimize the maximum likelihood through the optimization of Baum's “auxiliary function” of Equation 3. Equation 3: Q ( μ , μ ^ ) = ∑ θ ∈ states L ( O , θ μ ) log ( L ( O , θ μ ) ) ,
where L(O,θlμ) stands for the likelihood of the observation 0 , and the sequences of states, θ, given the specific mean vector μ.
On the other hand, if the adaptation technique is a Bayesian technique such as MAP equation 4 is used to adapt the speech models. Equation 4: μ MAP = τ μ 0 + ∑ t γ ( t ) o t τ + ∑ t γ ( t ) ,
In the above equation, τ is a measure of confidence on the prior (τ=15 in our experiments) and γ is the observed posterior probability of the observation.
Both adaptation techniques can be performed serially, that is, first one and then the other. The techniques of the invention support this application. Note that regardless of what adaptation technique is applied, the model adaptation procedure of the invention changes the way in which conventional adaptation techniques are applied by taking into account the incorrect solution provided by the N-best decoder and using them to emphasize the adaptation of the correct solution while deemphasizing the adaptation of the uncorrect one.
As noted above, while the adaptation system can be used in a single pass embodiment, as illustrated in FIG. 1, iteration may also be used to perform multi-pass adaptation upon the input adaptation data. One such multi-pass embodiment is illustrated in FIG. 2 . The embodiment of FIG. 2 is constructed essentially as described above, in which recognizer 10 supplies the N-best solutions 14 , which are then processed at 16 to extract reliable information. The information is then used to adapt the speech model at 18 , using any of the techniques described above.
In the multi-pass embodiment, the input adaptation data may be stored in an input buffer 20 , allowing the adaptation data to be processed multiple times after each successive adaptation is made to the model. Thus the input adaptation data is first analyzed by recognizer 10 using the initial speech models 12 and this results in modification of the speech models, as described above. Then, using the adapted speech models, the adaptation data from input buffer 20 is fed through the system again, to generate a second set of adapted speech models. The procedure is mediated by iterator 22 , which causes the adaptation cycle to repeat multiple times until the system converges upon a final solution. Convergence testing module 24 analyzes the N-best solutions 14 , comparing the current N-best solutions with the corresponding solutions from a previous pass. Altematively, it can be based on number of iterations. Once the convergence testing module detects that there is very little change in either the N-best solutions, or their respective likelihood scores, the iteration process is terminated.
The adaptation system of the invention, in either its single pass form or its multi-pass form, will selectively apply the adaptation technique (or techniques) based on the known sequence as labeled and on the one provided by the N-best solutions. To further understand the invention in operation, consider the following example taken from an exemplary application in which letters are spoken to input spelled words or names. Such a system might be used in a car navigation routing apparatus, for example. In this context the recognizer is trained to recognize individual letters (functioning as words) and an entire spelled name sequence would represent a series of letters (constituting a spoken sentence).
FIG. 3 summarizes the corrective N-best decoding procedure implemented by the system's illustrated in FIGS. 1 and 2. Specifically, FIG. 3 shows the iterative solution. A single pass solution would simply execute one pass through the illustrated sequence without iteratively repeating.
Referring to FIG. 3, the system performs a forced alignment according to the expected labeling of the sentence as indicated at step 100 . The expected labeling is known because the system performs supervised adaptation. Forced alignment amounts to aligning each uttered word in a spoken sequence to the words expected by the adaptation system.
Next, for each aligned segment of the sentence, the recognizer generates an N-best set of transcriptions and their corresponding likelihoods, as indicated at step 102 . The likelihoods, it will be recalled, are produced as a natural bi-product of the recognition system.
Next, weights are applied according to the Equation 1 described above. A correct label is assigned a positive weight and all incorrect labels are assigned negative weights. The data are accumulated for the entire phrase as at 104 . Then, the adaptation data is used at step 108 by the adaptation technique or techniques implemented in the system.
In effect, the system of the invention performs a corrective pre-processing of the adaptation data, such that adaptation of the correct solution is emphasized, using the incorrect solutions to enhance the discrimination.
In comparison with other discriminative methods, the corrective adaptation system of the invention has several advantages. It is computationally inexpensive and easy to implement. Moreover, it carries out discrimination that is specific to a speaker and convergence is not an issue. An interesting aspect of the invention is that observations associated with a negative weight can be regarded as additional observations that contribute to obtaining more reliable statistics. In other words, incorrectly labeled segments are not merely discarded. Rather, they are used to pull incorrect solutions away from the correct ones to thereby enhance the overall adaptation results.
To further illustrate the concept of corrective adaptation, consider the following example, in which the sound units being modeled correspond to individual letters and thus an input string or “sentence” would consist of a sequence of spoken letters, as if by spelling.
Assume that the correct spelling is “bop”.
A first use of the recognizer allows us to segment the adaptation speech, each segment representing one spelled letter.
For each segment, we use the recognizer to extract the N-best solutions with their respective
Likelihood, notes L s,n , where s represents the segment and n the nth best solution.
Assuming the answers are,
for the first segment: b,c,t,d, with their respective likelihood: L, 1,1 ,L 1,2 ,L 1,3 ,L 1,4 ,
for the second segment: e, o, u, p, with their respective likelihood: L 2,1 ,L 2,2 ,L 2,3 ,L 2,4 ,
for the third segment: p,b,c,t, with their respective likelihood: L 3,1 ,L 3,2 ,L 3,3 ,L 3,4 ,
According to Equation 1; we will obtain: φ 1 , 1 = κ ; φ 1 , 2 = ρ ( L 1 , 2 - L 1 , 1 ) η ; φ 1 , 3 = - ρ ( L 1 , 3 - L 1 , 1 ) η ; φ 1 , 4 = - ρ ( L 1 , 4 - L 1 , 1 ) η , φ 2 , 1 = - ρ ; φ 2 , 2 = κ ; φ 2 , 3 = - ρ ( L 2 , 3 - L 2 , 1 ) η ; φ 2 , 4 = - ρ ( L 2 , 4 - L 2 , 1 ) η , φ 3 , 1 = κ ; φ 3 , 2 = - ρ ( L 3 , 2 - L 3 , 1 ) η ; φ 3 , 3 = - ρ ( L 3 , 3 - L 3 , 1 ) η ; φ 3 , 4 = - ρ ( L 3 , 4 - L 3 , 1 ) η .
Focusing on the model “b”, its own data set will be, the first segment with a positive weight=φ 1,1 , and the third segment, with a negative weight=φ 3,2 .
In the standard adaptation techniques (MLLR, MAP), a weighting factor, γ m (t), called “state occupancy” is used to weight the adaptation of the model m with every frame, extracted from the adaptation speech.
In this corrective adaptation, this weighting factor is multiplied with our corrective weight, φ s,n .
Assuming the state occupancy of the model “b” for the first segment to be γ 1,b (t) , the new corrective weight will be: γ o 1,b (t) =γ 1,b (t)φ 1,1 . For the third segment: γ o 3,b (t) =γ 3,b (t)φ 3,2 and zero for the other segments.
In the MLLR adaptation, γ s,m o (t) is used to estimate the transformation matrix, W, which is used to adapt the mean of the adapted models as followed:
{circumflex over (μ)} =W μ+b,
where, μ=[μ 1 , μ 2 , . . . , μ M ] T is the matrix containing all the original means of the M models, {circumflex over (μ)} =[{circumflex over (μ)} 1 , {circumflex over (μ)} 2 , . . . , {circumflex over (μ)} M ] T is the matrix containing all the original means of the M models and b is a biais matrix not used in out experiments.
In more details, the elements of the transformation matrix, W can be estimated by: ( W ( i , j ) ) T = G i - 1 ( Z ( i , j ) ) T
where Z can be estimated with: z = ∑ m ∑ s ∑ t γ s , m ( t ) m c - 1 o ( 1 ) [ 1 ; μ T - ] T
and G i is a matrix such that its elements, G i (j,q) are estimated with G i ( j , q ) = ∑ m V m ( i , i ) D m ( j , q )
where V m (i,i) and D m (j,q) are the element of the matrixes: V m = ∑ s ∑ t γ s , m ( t ) C m - 1 D m = [ 1 ; μ m T ] [ 1 ; μ m T ] T
μ m and C m represent the current mean and inverse variance of the model m, o s (t) represent the acoustic vector extracted from the segment s at time t of the adaptation speech.
In the MAP adaptation, γ s,m o (t) is used as followed: μ ^ m = τμ m + ∑ s ∑ m γ s , m o ( t ) o s ( t ) τ + ∑ s ∑ m γ s , m o ( t )
While the invention has been described in its presently preferred embodiments, it will be understood that the invention is capable of modification without departing from the spirit of the invention as set forth in the appended claims.
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Supervised adaptation speech is supplied to the recognizer and the recognizer generates the N-best transcriptions of the adaptation speech. These transcriptions include the one transcription known to be correct, based on a priori knowledge of the adaptation speech, and the remaining transcriptions known to be incorrect. The system applies weights to each transcription: a positive weight to the correct transcription and negative weights to the incorrect transcriptions. These weights have the effect of moving the incorrect transcriptions away from the correct one, rendering the recognition system more discriminative for the new speaker's speaking characteristics. Weights applied to the incorrect solutions are based on the respective likelihood scores generated by the recognizer. The sum of all weights (positive and negative) are a positive number. This ensures that the system will converge.
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FIELD OF THE INVENTION
The invention relates to non-metallocene catalysts useful for polymerizing olefins. The catalysts incorporate a tridentate dianionic ligand.
BACKGROUND OF THE INVENTION
While Ziegler-Natta catalysts are a mainstay for polyolefin manufacture, single-site (metallocene and non-metallocene) catalysts represent the industry's future. These catalysts are often more reactive than Ziegler-Natta catalysts, and they produce polymers with improved physical properties. The improved properties include controlled molecular weight distribution, reduced low molecular weight extractables, enhanced incorporation of α-olefin comonomers, lower polymer density, controlled content and distribution of long-chain branching, and modified melt rheology and relaxation characteristics.
Traditional metallocenes incorporate one or more cyclopentadienyl (Cp) or Cp-like anionic ligands such as indenyl, fluorenyl, or the like, that donate pi-electrons to the transition metal. Non-metallocene single-site catalysts, including ones that capitalize on the chelate effect, have evolved more recently. Examples are the bidentate 8-quinolinoxy or 2-pyridinoxy complexes of Nagy et al. (see U.S. Pat. No. 5,637,660), the late transition metal bisimines of Brookhart et al. (see Chem. Rev. 100 (2000) 1169), and the diethylenetriamine-based tridentate complexes of McConville et al. or Shrock et al. (e.g., U.S. Pat. Nos. 5,889,128 and 6,271,323).
In numerous recent examples, the bi- or tridentate complex incorporates a pyridyl ligand that bears a heteroatom β- or γ- to the 2-position of the pyridine ring. This heteroatom, typically nitrogen or oxygen, and the pyridyl nitrogen chelate the metal to form a five- or six-membered ring. For some examples, see U.S. Pat. Nos. 7,439,205; 7,423,101; 7,157,400; 6,653,417; and 6,103,657 and U.S. Pat. Appl. Publ. No. 2008/0177020. In some of these complexes, an aryl substituent at the 6-position of the pyridine ring is also available to interact with the metal through C—H activation to form a tridentate complex (see, e.g., U.S. Pat. Nos. 7,115,689; 6,953,764; 6,706,829).
Complexes in which a 2-(2-aryloxy)pyridyl group forms part of a tridentate ligand are known (see, e.g., U.S. Pat. Nos. 7,423,101; 7,049,378; and 7,253,133. U.S. Pat. Appl. Publ. No. 2008/0177020 and Organometallics 27 (2008) 6245 are of particular interest. They describe tridentate, dianionic complexes, including Group 4 complexes, and their use as non-metallocene catalysts for olefin polymerization. The complexes include a “linker group,” most commonly phenyl, pyridyl, furanyl, or thiphenyl joins two 2-aryloxy groups. Thus, e.g., the references show bis-2,6-(2-aryloxy)pyridine complexes. Complexes in which a quinoline moiety is used as a linker are not disclosed.
Quinoline-based bi- or tridentate complexes have been described (see, e.g., U.S. Pat. Nos. 7,253,133; 7,049,378; 6,939,969; 6,103,657; 5,637,660 and Organometallics 16 (1997) 3282), although less frequently than their pyridyl analogs. These complexes lack a 2-(2-aryloxy)quinoline ligand and/or they are not dianionic and tridentate. U.S. Pat. No. 7,253,133 discloses numerous tridentate complexes and ligand precursors, many of which have a 2-aryloxy group. Tridentate monoanionic complexes that incorporate a pyridyl group (“A-5,” col. 34) or quinolinyl group (“A-6,” col. 34) are shown, and complex A-6 does not feature a 2-(2-aryloxy)quinoline ligand. Similar complexes are shown in U.S. Pat. No. 7,049,378 (see Exs. 1 and 2), both monoanionic; Example 2 shows a quinoline, but not a 2-(2-aryloxy)quinoline.
New non-metallocene catalysts useful for making polyolefins continue to be of interest. In particular, tridentate complexes that can be readily synthesized from inexpensive reagents are needed. The complexes should not be useful only in homogeneous environments; a practical complex can be supported on silica and readily activated toward olefin polymerization with alumoxanes or boron-containing cocatalysts. Ideally, the catalysts have the potential to make ethylene copolymers having high or very high molecular weights and can be utilized in high-temperature solution polymerizations.
SUMMARY OF THE INVENTION
The invention relates to catalysts useful for polymerizing olefins. The catalysts comprise an activator and a Group 4 metal complex. The complex incorporates a dianionic, tridentate 2-(2-aryloxy)quinoline or 2-(2-aryloxy)-dihydroquinoline ligand. In one aspect, a supported catalyst is prepared by first combining a boron compound having Lewis acidity with excess alumoxane to produce an activator mixture, followed by combining the activator mixture with a support and the dianionic, tridentate Group 4 metal complex. The catalysts are easy to synthesize, support, and activate, and they enable facile production of high-molecular-weight polyolefins.
DETAILED DESCRIPTION OF THE INVENTION
Catalysts of the invention are particularly useful for polymerizing olefins. They comprise an activator and a Group 4 transition metal complex. Group 4 is metals include zirconium, titanium, and hafnium. Zirconium and titanium are particularly preferred. The catalysts may include mixtures of different complexes.
The catalysts include one or more activators. The activator helps to ionize the complex and activate the catalyst. Suitable activators are well known in the art. Examples include alumoxanes (methyl alumoxane (MAO), PMAO, ethyl alumoxane, diisobutyl alumoxane), alkylaluminum compounds (triethylaluminum, diethylaluminum chloride, trimethylaluminum, triisobutylaluminum), and the like. Suitable activators include boron and aluminum compounds having Lewis acidity such as ionic borates or aluminates, organoboranes, organoboronic acids, organoborinic acids, and the like. Specific examples include lithium tetrakis(pentafluorophenyl)borate, lithium tetrakis(pentafluorophenyl)aluminate, anilinium tetrakis(pentafluorophenyl)-borate, trityl tetrakis(pentafluorophenyl)borate (“F20”), tris(pentafluorophenyl)-borane (“F15”), triphenylborane, tri-n-octylborane, bis(pentafluorophenyl)borinic acid, pentafluorophenylboronic acid, and the like. These and other suitable boron-containing activators are described in U.S. Pat. Nos. 5,153,157, 5,198,401, and 5,241,025, the teachings of which are incorporated herein by reference. Suitable activators also include aluminoboronates—reaction products of alkyl aluminum compounds and organoboronic acids—as described in U.S. Pat. Nos. 5,414,180 and 5,648,440, the teachings of which are incorporated herein by reference. Particularly preferred activators are alumoxanes, boron compounds having Lewis acidity, and mixtures thereof.
In addition to the Group 4 metal, the complex includes a dianionic, tridentate 2-(2-aryloxy)quinoline or 2-(2-aryloxy)dihydroquinoline ligand. The ligand is “tridentate” and “dianionic” in that it binds to the metal with two anionic sites and one neutral site. The neutral site is the tertiary amine group of the quinoline moiety. The anionic sites include at least one 2-aryloxy group that is attached at the 2-position of the quinoline (or dihydroquinoline) moiety. The other anionic group is normally attached at the 8-position of the quinoline ring and can incorporate any of a variety of carbon, oxygen, nitrogen, or sulfur anions. The other anionic group coordinates with the Group 4 metal to give a 5-, 6-, or 7-membered ring in the tridentate complex. Preferably, the other anionic group is an 8-anilino or an 8-(2-aryloxy) substituent.
Some preferred complexes of the invention are 2-(2-aryloxy)-8-anilinoquinolines, i.e., they have an aniline-based substituent attached at the 8-position of the quinoline ring. Particularly preferred among these are complexes that have the structure:
in which M is a Group 4 transition metal, Ar is an aryl group, each X is independently selected from the group consisting of halide, amide, alkyl, aryl, and alkaryl, and any of the ring carbons is optionally substituted with an alkyl, aryl, halide, alkoxy, trialkylsilyl, dialkylamino, or haloalkyl group, or any pair of adjacent ring carbons are joined to form a 5 to 7-membered carbocyclic or heterocyclic ring.
More preferred complexes of this type have the structure:
in which Bn is benzyl and each R is independently selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, and tert-butyl.
Other preferred complexes are 2,8-bis(2-aryloxy)quinolines, i.e., they have a 2-aryloxy substitutent attached to both the 2- and 8-positions of the quinoline ring. Particularly preferred among these are complexes that have the structure:
in which M is a Group 4 transition metal, each X is independently selected from the group consisting of halide, amide, alkyl, aryl, and alkaryl, and any of the ring carbons is optionally substituted with an alkyl, aryl, halide, alkoxy, trialkylsilyl, dialkylamino, or haloalkyl group, or any pair, of adjacent ring carbons are joined to form a 5 to 7-membered carbocyclic or heterocyclic ring.
Particularly preferred complexes of this type have the structure:
in which Bn is benzyl and each R is independently selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, and tert-butyl.
Other preferred complexes are 2,8-bis(2-aryloxy)dihydroquinolines. Some of these complexes have the structure:
in which M is a Group 4 transition metal, each X is independently selected from the group consisting of halide, amide, alkyl, aryl, and alkaryl, and any of the ring carbons is optionally substituted with an alkyl, aryl, halide, alkoxy, trialkylsilyl, dialkylamino, or haloalkyl group, or any pair of adjacent ring carbons are joined to form a 5 to 7-membered carbocyclic or heterocyclic ring.
Particularly preferred complexes of this type have the structure:
in which Bn is benzyl and each R is independently selected from the group consisting of methyl, ethyl, n-propyl, isopropyl, n-butyl, and tert-butyl.
Still other complexes are 2-(2-aryloxy)-8-arylquinolines, in which an aryl ring provides a carbanionic center to complete the tridentate structure. Preferred complexes of this type have the structure:
in which M is a Group 4 transition metal, each X is independently selected from the group consisting of halide, amide, alkyl, aryl, and alkaryl, and any of the ring carbons is optionally substituted with an alkyl, aryl, halide, alkoxy, trialkylsilyl, dialkylamino, or haloalkyl group, or any pair of adjacent ring carbons are joined to form a 5 to 7-membered carbocyclic or heterocyclic ring.
A few exemplary complexes:
The catalysts are preferably supported on an inorganic oxide such as silica, alumina, silica-alumina, magnesia, titania, zirconia, clays, zeolites, or the Ike. Silica is preferred. When silica is used, it preferably has a surface area in the range of 10 to 1000 m 2 /g, more preferably from 50 to 800 m 2 /g and most preferably from 200 to 700 m 2 /g. Preferably, the pore volume of the silica is in the range of 0.05 to 4.0 mL/g, more preferably from 0.08 to 3.5 mL/g, and most preferably from 0.1 to 3.0 mL/g. Preferably, the average particle size of the silica is in the range of 1 to 500 microns, more preferably from 2 to 200 microns, and most preferably from 2 to 45 microns. The average pore diameter is typically in the range of 5 to 1000 angstroms, preferably 10 to 500 angstroms, and most preferably 20 to 350 angstroms.
The support is preferably treated thermally, chemically, or both prior to use by methods well known in the art to reduce the concentration of surface hydroxyl groups. Thermal treatment consists of heating (or “calcining”) the support in a dry atmosphere at elevated temperature, preferably greater than 100° C., and more preferably from 150 to 800° C., prior to use. A variety of different chemical treatments can be used, including reaction with organo-aluminum, -magnesium, -silicon, or -boron compounds. See, for example, the techniques described in U.S. Pat. No. 6,211,311, the teachings of which are incorporated herein by reference.
Highly active non-metallocene catalysts of the invention can be made by using a particular sequence for activating and supporting the tridentate dianionic complexes. One method of preparing a supported catalyst useful for polymerizing olefins comprises two steps. In a first step, a boron compound having Lewis acidity (as described earlier) is combined with excess alumoxane, preferably methylalumoxane, to produce an activator mixture. In a second step, the resulting activator mixture is combined with a support, preferably silica, and a complex which comprises a Group 4 transition metal and a dianionic, tridentate 2-(2-aryloxy)quinoline or 2-(2-aryloxy)dihydroquinoline ligand. In one approach, the activator mixture is combined with the complex first, followed by the support. However, the order can be reversed; thus, the activator mixture can be combined with the support first, followed by the complex. Preferably, the ligand is a 2-(2-aryloxy)-8-anilinoquinoline, a 2,8-bis(2-aryloxy)quinoline, a 2,8-bis(2-aryloxy)dihydroquinoline, or a 2-(2-aryloxy)-8-arylquinoline.
In a typical example, the boron compound is combined with excess MAO in a minimal amount of a hydrocarbon. The complex is added and the combined mixture is then added to a large proportion of calcined silica in an incipient wetness technique to provide the supported catalyst as a free-flowing powder.
As the results in Polymerization Examples 1-3 below show, dianionic tridentate 2-(2-aryloxy)quinoline and 2-(2-aryloxy)dihydroquinoline complexes are active olefin polymerization catalysts. In particular, Method D generally provides non-metallocene catalysts with excellent activity. Compare the activity results of a supported catalyst made by Method D, Polymerization Example 2 (with complex 52) versus Method A, Polymerization Example 3 (MAO-treated silica, slurry technique, no borate). The increase in activity from Method D with these complexes is substantial and unexpected.
The invention includes processes for polymerizing olefins. In one process, at least one of ethylene, propylene, and an α-olefin is polymerized in the presence of a catalyst of the invention. Preferred α-olefins are C 4 -C 20 α-olefins such as 1-butene, 1-hexene, 1-octene, and the like. Ethylene and mixtures of ethylene with propylene or a C 4 -C 10 α-olefin are particularly preferred. Most preferred are polymerizations of ethylene with 1-butene, 1-hexene, 1-octene, and mixtures thereof
Many types of olefin polymerization processes can be used. Preferably, the process is practiced in the liquid phase, which can include slurry, solution, suspension, or bulk processes, or a combination of these. High-pressure fluid phase or gas phase techniques can also be used. In a preferred olefin polymerization process, a supported catalyst of the invention is used. The to polymerizations can be performed over a wide temperature range, such as −30° C. to 280° C. A more preferred range is from 30° C. to 180° C.; most preferred is the range from 60° C. to 100° C. Olefin partial pressures normally range from 15 psig to 50,000 psig. More preferred is the range from 15 psig to 1000 psig.
The following examples merely illustrate the invention. Those skilled in the art will recognize many variations that are within the spirit of the invention and scope of the claims.
All intermediate compounds and complexes synthesized give satisfactory 1 H NMR spectra consistent with the structures indicated.
Preparation of Complex 34
8-Bromo-2-(3,5-di-tert-butyl-2-methoxyphenyl)quinoline
A mixture of 2,8-dibromoquinoline (4.64 g, 16 mmol, prepared by the method of L. Mao et al., Tetrahedron Lett. 46 (2005) 8419), 3,5-di-tert-butyl-2-methoxyphenylboronic acid (4.3 g, 16 mmol), K 2 CO 3 (5.6 g, 40 mmol), Pd(OAc) 2 (0.08 g, 0.3 mmol), P(o-Tol) 3 (0.2 g, 0.6 mmol), dimethoxyethane (40 mL) and water (10 mL) is refluxed for 8 h with stirring in an argon atmosphere. The mixture is then poured into water and extracted with CHCl 3 (3×50 mL). The combined organic phase is washed with water and brine, and then concentrated. The residue is purified by column chromatography (silica gel 40, hexane/CH 2 Cl 2 4:1). Yield: 5.2 g (77%).
2-(8-Bromo-2-quinolinyl)-4,6-di-tert-butylphenol
A mixture of 8-bromo-2-(3,5-di-tert-butyl-2-methoxyphenyl)quinoline (4.89 g, 11.5 mmol), BBr 3 (1.63 mL, 18 mmol), and CH 2 Cl 2 (50 mL) is stirred for 4 h at 20° C. The reaction mixture is then diluted with cold water (100 mL). The organic phase is separated, washed with water and brine, and then to concentrated. The residue is recrystallized from hexane/benzene. Yield: 3.3 g (70%).
2,4-Di-tert-butyl-6-[8-(2,6-dimethylanilino)-2-quinolinyl]phenol
A mixture of 2-(8-bromo-2-quinolinyl)-4,6-di-tert-butylphenol (3.3 g, 8 mmol), 2,6-dimethylaniline (1.2 mL, 10 mmol), Pd(dba) 2 (0.036 g, 0.6 mmol), L=(N-[2′-(dicyclohexylphosphino)[1,1′-biphenyl]-2-yl]-N,N-dimethylamine) (0.05 g, 0.12 mmol), NaO t Bu (0.36 g, 3.6 mmol), and toluene (8 mL) is stirred for 8 h under an argon atmosphere at 100° C. The mixture is then poured into water and extracted with benzene (3×50 mL). The combined organic phase is washed with water and brine, and is then concentrated. The residue is purified by column chromatography (silica gel 40, hexane/toluene 2:1). Yield: 2.17 g (60%).
Dibenzylhafnium 2,4-Di-tert-butyl-6-[8-(2,6-dimethylanilino)-2-quinolinyl]-phenolate (34)
A solution of tetrabenzylhafnium (0.47 g, 0.86 mmol) in toluene (5 mL) is added at 0° C. to a solution of 2,4-di-tert-butyl-6-[8-(2,6-dimethylanilino)-2-quinolinyl]phenol (0.30 g, 0.66 mmol) in toluene (10 mL). The color of the mixture changes from pale yellow to yellow-orange. The resulting mixture is allowed to warm to room temperature and is then stirred for 8 days at 40° C. The mixture is evaporated, and pentane (20 mL) is added. The crystalline precipitate is separated by decantation, washed with pentane, and dried in vacuo. Yield of 34, a yellow crystalline powder: 0.26 g (48%). 1 H NMR (C 6 D 6 ) δ: 7.74-7.66 (m, 3H); 7.45 (d, 1H); 7.22 (d, 1H); 7.15-7.13 (m, 3H); 6.99 (t, 1H); 6.79-6.62 (m, 10H); 6.18 (d, 1H); 2.40 (d, 2H); 2.31 (s, 6H); 1.97 (d, 2H); 1.75 (s, 9H); 1.36 (s, 9H).
Preparation of Complex 52
2,4-Di-tert-butyl-1-(methoxymethoxy)benzene
A solution of 2,4-di-tert-butylphenol (20.6 g, 0.1 mol) in dry THF (50 mL) is added with stirring to a suspension of NaH (2.4 g, 0.1 mol) in dry THF (150 mL). After 1 h of stirring, the mixture is cooled to 0° C., and chloromethyl methyl ether (7.6 mL, 0.1 mol) is added. The reaction mixture is stirred at room temperature for 2 h, quenched with water (500 mL) and extracted with Et 2 O (2×100 mL). The combined organic phase is dried over MgSO 4 and evaporated under reduced pressure. The residue is used for the next step without purification.
2,8-Bis(2-methoxymethoxy-3,5-di-tert-butylphenyl)quinoline
n-Butyllithium (8 mL of 2.5 M solution in hexane) is added to a solution of 2,4-di-tert-butyl-1-(methoxymethoxy)benzene (4.8 g, 19.2 mmol) in Et 2 O (100 mL). The mixture is stirred at room temperature for 3 h. THF (80 mL) and zinc chloride (2.6 g, 19.2 mmol) are then added and stirred until the ZnCl 2 dissolves. After that, Pd(dba) 2 (0.3 g), P(o-Tol) 3 (0.3 g), and 2,8-dibromoquinoline (2.6 g, 9 mmol) are added. The mixture is stirred overnight, then poured into excess water and extracted with Et 2 O (3×100 mL). The combined organic phase is dried over MgSO 4 and concentrated under reduced pressure. The product is purified by column chromatography (SiO 2 , hexane/CHCl 3 1:1). Yield: 2.6 g (46%).
2,8-Bis(2-hydroxy-3,5-di-tert-butylphenyl)quinoline
A mixture of 2,8-bis(2-methoxymethoxy-3,5-di-tert-bytylphenyl)quinoline (2.6 g) and 5% aq. HCl (30 mL) is heated on a water bath for 1 h. After cooling, the product is filtered off and recrystallized from methanol. Yield: 2 g (90%). 1 H NMR (CDCl 3 ) δ: 13.73 (br. s., 1H); 8.32 (d, 1H); 8.10 (d, 1H); 7.91 (d, 1H); 7.83 (d, 1H); 7.78 (d, 1H); 7.65 (t, 1H); 7.53 (d, 1H); 7.42 (d, 1H); 7.14 (d, 1H); 4.95 (b.s., 1H); 1.51 (s, 9H); 1.39 (s, 27H). 13 C NMR (CDCl 3 ) δ: 159.4; 157.5; 149.1; 144.1; 142.4; 139.3; 137.8; 137.6; 135.9; 135.6; 132.67; 127.9; 126.9; 126.7; 126.3; 125.3; 125.0; 124.2; 121.4; 118.6; 117.9; 35.2; 35.1; 34.4; 34.3; 31.65; 31.6; 29.9; 29.5.
Dibenzylzirconium 2-benzyl-2,8-bis(3,5-di-tert-butyl-6-phenolato)-1,2-dihydroquinoline (52)
Tetrabenzylzirconium (0.46 g, 1 mmol) is added at 0° C. to a solution of 2,8-bis(2-hydroxy-3,5-di-tert-butylphenyl)quinoline (0.44 g, 0.82 mmol) in toluene (20 mL). The resulting mixture is allowed to warm to room temperature and is then stirred for 8 h at 45-50° C. The color of the mixture changes from pale yellow to yellow-orange. Toluene is evaporated and the residue is treated with hexane. A crystalline solid, the primary product, forms. This solid is recrystallized from hexane (hence the temperature of the solution reaches at least 60-70° C.), and a secondary product is isolated. Yield of 52, a yellow crystalline powder: 0.39 g (59%). The structure of 52 is confirmed by an X-ray crystal structure and 1 H NMR spectrum of the recrystallized product.
Preparation of Supported Catalysts
Method A
A mixture of silica (Davison 948, calcined at 250° C. for 4 h, 2.0 g), methylalumoxane (30 wt.% solution of MAO in toluene, product of Albemarle, 2.2 mL), and toluene (10 mL) is stirred under nitrogen for 1 h at 80° C. The resulting slurry is cooled to ambient temperature, and a specified amount of catalyst precursor is added, dry or in toluene solution, under stirring. After 30 min., the slurry is filtered and the solids are rinsed with hexanes (2×5 mL) and dried. The resulting catalyst is used in polymerization tests.
Method D
Trityl tetrakis(pentafluorophenyl)borate (0.093 g) is added to methylalumoxane (30 wt.% solution of MAO in toluene, 2.0 mL), and the mixture is stirred for 15 min. A specified amount of complex precursor is added to the MAO/borate solution, and the mixture stirs for an additional 15 min. The resulting product is slowly added to a stirred bed of silica (Davison 948, calcined at 600° C. for 6 h, 2.0 g). The resulting free-flowing powder is used in polymerization tests.
Ethylene Polymerization
General Procedure
A dry, 2-L stainless-steel autoclave is charged with isobutane (1.0 L), triisobutylaluminum (1 M solution in hexanes, 2 mL), 1-butene (100 mL) and, optionally, hydrogen, and the contents are heated to 70° C. and pressurized with ethylene (15.5 psi partial pressure). Polymerization is started by injecting the is catalyst with a small quantity of isobutane. The temperature is maintained at 70° C., and ethylene is supplied on demand throughout the test. The reaction is terminated by cooling the reactor and venting its contents.
Polymerization Example 1
A catalyst batch is prepared using Method D and complex 34 (97.0 mg) resulting in an Al/B/Hf ratio of 77/1.2/1. A sample of catalyst corresponding to 5.0 mg of the complex is used in the polymerization test. The test yields 14.6 g of high molecular weight ethylene/butene copolymer in 70 minutes (activity: 2027 kg/mol Hf/h).
Polymerization Example 2
A catalyst batch is prepared using Method D and complex 52 (39.6 mg) resulting in an Al/B/Zr ratio of 190/1.2/1. A sample of catalyst corresponding to 5.0 mg of the complex is used in the polymerization test. The test yields 43.9 g of high molecular weight ethylene/butene copolymer in 39 minutes (activity: 10,914 kg/mol Zr/h).
Polymerization Example 3
A catalyst batch is prepared using Method A and complex 52 (75.0 mg) resulting in an Al/Zr ratio of 100/1. A sample of catalyst corresponding to 5.0 mg of the complex is used in the polymerization test. The test yields 4.1 g of high molecular weight ethylene/butene copolymer in 70 minutes (activity: 568 kg/mol Zr/h).
The preceding examples are meant only as illustrations. The following claims define the invention.
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Catalysts useful for polymerizing olefins are disclosed. The catalysts comprise an activator and a Group 4 metal complex that incorporates a dianionic, tridentate 2-(2-aryloxy)quinoline or 2-(2-aryloxy)dihydroquinoline ligand. In one aspect, supported catalysts are prepared by first combining a boron compound having Lewis acidity with excess alumoxane to produce an activator mixture, followed by combining the activator mixture with a support and the tridentate, dianionic Group 4 metal complex. The catalysts are easy to synthesize, support, and activate, and they enable facile production of high-molecular-weight polyolefins.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application is related to US Provisional Patent Application No. 60/610,891 filed Sep. 17, 2004 entitled Distributed Mass Spectrometry, which is incorporated fully herein by reference.
TECHNICAL FIELD
[0002] The present invention relates to distributive mass spectrometry and more particularly, to a device, method, and system for locating components of a mass spectrometry system remotely.
BACKGROUND INFORMATION
[0003] Mass spectrometry allows for the quantization of atoms or molecules for determining chemical and structural information about molecules. Mass spectrometers use the difference in mass-to-charge ratio (m/e) of ionized atoms or molecules to identify the atom or molecule. Molecules have distinctive fragmentation patterns that provide structural information to identify structural components. Mass spectrometers are used in industry and academia for both routine and research purposes. Mass spectrometry has a wide range of applications in the biological, the chemical, and the physical sciences.
[0004] The general operation of a mass spectrometer can be broken down into three steps. The first step involves creating gas-phase ions. The second step separates the ions in space or time based on their mass-to-charge ratio. The third step measures the quantity of ions of each mass-to-charge ratio. By performing a Fourier transformation the time domain measurements are converted to a frequency domain. The ion separation power of a mass spectrometer is described by the resolution, which is defined as: R=m/delta m, where m is the ion mass and delta m is the difference in mass between two resolvable peaks in a mass spectrum.
[0005] The sample is injected into a measurement chamber along a magnetic axis. The sample is exposed to a high-energy electron beam while contained by the magnetic field and two positively charged plates. Excitation plates give the ions a radio frequency pulse, which boosts the ions into larger orbits. The frequency of these orbits for each different ion is proportional to its mass divided by its charge. These orbiting ions create a complex radio emission that is the sum of all of the various ion frequencies. Two receiver plates detect this time-domain signal. A Fourier transform is performed on the signal yielding a frequency spectrum.
[0006] As mass spectrometry has evolved the components have been located within close proximity of each other. In the Quantra system, manufactured by Siemens Applied Automation of Bartlesville, OK, the ionization source, vacuum pump system, measurement chamber and control boards are located within a single housing (cabinet). Mass spectrometers are often designed to be within a single housing in order to reduce the overall size of the equipment and to allow for transportability.
[0007] Some applications may benefit from separating the administrator from the measurement chamber. For example, when analyzing hazardous material, current mass spectrometers require the administrator to wear protective gear. In addition, some applications may analyze material that may produce electro-magnetic waves. These electro-magnetic waves may interfere with the circuitry of the control boards. Accordingly, a need exists for a device, method, and system that provide components of a mass spectrometry system remotely.
SUMMARY
[0008] The present invention is a novel device, system, and method for providing remote mass spectrometry. The exemplary system may have an ion source for injecting ions and a measurement chamber. The measurement chamber may be coupled to the ion source for receiving and detecting signals of the ions. The measurement chamber may have an analysis cell, a magnet, and an ionizing device. A control board may be in communication with the measurement chamber. The control board may receive signals received and detected by the measurement chamber. The control board may be located remotely and have a processor for analyzing the signal.
[0009] The invention may include the following embodiments. The ion source may be located remotely and inject ions through a conduit in communication with the measurement chamber. The vacuum system may be controlled remotely by the control board. The measurement chamber may also have a filter portion for filtering the received and detected signal. The control board may be in communication with a computer control and display system. An amplifier may be in communication with and located between the measurement chamber and control board. The control board may be located more than three feet away from the measurement chamber. The control board and ion source may be located remotely from the measurement chamber within a remote movable housing. The measurement chamber may be located in a local movable housing coupled via a conduit and communication lines to the remote movable housing.
[0010] It is important to note that the present invention is not intended to be limited to a system or method which must satisfy one or more of any stated objects or features of the invention. It is also important to note that the present invention is not limited to the exemplary embodiments described herein. Modifications and substitutions by one of ordinary skill in the art are considered to be within the scope of the present invention, which is not to be limited except by the following claims.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] These and other features and advantages of the present invention will be better understood by reading the following detailed description, taken together with the drawings herein:
[0012] FIG. 1 is a block diagram of a mass spectrometry system with a control board located remotely according to the exemplary control board embodiment 100 of the present invention.
[0013] FIG. 2 is a block diagram of a mass spectrometry system with a control board located remotely according to a second exemplary control board embodiment 200 of the present invention.
[0014] FIG. 3 is a flow chart illustrating a mass spectrometry method with a control board located remotely according to an exemplary control board method embodiment 300 of the present invention.
[0015] FIG. 4 is a block diagram of a mass spectrometry system with a vacuum system located remotely according to an exemplary vacuum system embodiment 400 of the present invention.
[0016] FIG. 5 is a block diagram of a mass spectrometry system with a sample supply located remotely according to an exemplary sample supply embodiment 500 of the present invention.
DETAILED DESCRIPTION
[0017] The present invention provides for a distributed approach to mass spectrometry. In particular, the present invention allows for minimizing space/weight in order to achieve a more compact on-site unit. The present invention also allows the administrator to conduct the mass spectrometry remotely. According to an exemplary embodiment, the control boards may be separated from the measurement chamber, vacuum system and ion source. In doing so, the measuring unit minimizes weight and volume.
[0018] Referring to FIG. 1 , an exemplary control board embodiment 100 provides for local housing 102 that holds measurement chamber 104 . Control board 106 is located remotely from local housing 102 . Measurement chamber 104 may include an pumping device that may be used to evacuate the measurement chamber. (not shown). For example, the pumping device may be an internal 6.5 KV Ion pump or any other suitable pump to achieve a nominal 10 −10 Torr I/s. More particularly, the ionizing device may be a high-energy beam that ionizes samples and creates molecular fragments of predictable patterns that indicate the type of compounds present in the sample and the relative amounts of such compounds. Within measurement chamber 104 a permanent Magnet may also be housed (not shown), for example, a 1-Tesla (nominal) permanent magnet, and such magnet may be used to generate a magnetic field. Measurement chamber 104 may also include an analyzer cell (not shown) where measurement data of an ionized sample may be collected. The measurement data may be collected by receiver plates (not shown) located within the analyzer cell. After collecting measurement data, the receiver plates may transmit a measurement data signal outside measurement chamber 104 and local housing 102 to control board 106 .
[0019] According to the above exemplary embodiment, local housing 102 may also house a sample supply 110 and vacuum system 112 . Sample supply 110 provides sample material to measurement chamber 104 in gaseous form. The environmental conditions of sample supply 110 are regulated so as to provide the sample material in a gaseous form. Stainless steel piping or other suitable material acts as a conduit to supply the gaseous sample to measurement chamber 104 . A valve or other suitable flow control mechanism is controlled by control board 106 and is periodically opened to allow for a controlled flow of gaseous sample material to enter measurement chamber 104 for ionization. Sample supply. 110 may also include filters and other equipment necessary in order to provide a clean and pure gaseous sample to measurement chamber 104 . Vacuum system 112 supplies a vacuum to maintain the necessary conditions of the sample material during the testing and analyzing process.
[0020] The control board 106 receives the measurement data signal from the receiver plates and processes the signal. Control board 106 may include multiple circuit boards. Control board 106 may include a back plane in order to accept and provide connections to multiple circuit boards. One exemplary circuit board may include a 6-layer, 64 megabit CPU board, with a CPU. An example of such a CPU may be a Triton II HX chipsets and enhanced I/O chipset manufactured by Intel®. Other circuit boards may include a network interface card, a waveform generator, a digital signal processor, and one or more analog data input boards. In operation, the waveform generator board may perform waveform generation and data acquisition functions. The digital signal processor may be used to assist in the processing of the measurement data signal. For example, the digital signal processor may be the Hawk-81, a Momentum Data Systems Digital Signal Processor (DSP) board for the ISA bus and a Modular Analog Front End (MAFE) daughter board. One illustrative configuration may include a MAFE with an AD-1847 stereo codex. In operation, the Hawk-81 uses a MAFE to access the external analog measurement data signal and digitizes the signal. The analog boards-monitor, control, and generate drive signals for the various components of the mass spectrometer.
[0021] Control board 106 transmits control signals to measurement chamber 104 to allow an administrator to control the various components of the mass spectrometer. Control board 106 may also allow the administrator to monitor conditions in measurement chamber 104 . Sensors located within measurement chamber 104 may relay data to control board 106 via communication lines. Such communication lines may be hardwired (e.g., copper wire, fiber optic, etc.) or may be wireless (e.g., radio frequency). Control board 106 may automatically, based on preprogrammed parameters or commands provided by the administrator, make adjustments to valves, actuators, or other various components of the mass spectrometer. Such control signals may be sent from control board 106 over a communication line to the mass spectrometers various components.
[0022] As shown in FIG. 1 , control board 106 may be stored located remotely from local housing 102 and may be located within a separate remote housing (not shown). Control board 106 may include a variety of input and output devices to communicate with the administrator. For example, a combination of hardware and software may provide the administrator with a graphical user interface (GUI) 108 to administer the mass spectrometer process. Control board 106 may also be networked with other computers to allow remote access by other administrators or software applications.
[0023] Local housing 102 may be a cabinet with a front door to access the components of the mass spectrometer stored internally. The cabinet may be on rollers to allow the administrator to move the mass spectrometer to a testing location. Local housing 102 may include a power supply for providing power to measurement chamber 104 , sample supply 110 and vacuum system 112 . The components of the local housing may be connected to control board 106 via communication lines. The communication lines may include a variety of analog and digital lines of communication (e.g., copper wire, fiber optic cables, radio frequency, etc.). The control signals, sensor signals, and measurement data signals are communicated between the components of local housing 102 and control board 106 via the above-mentioned communication lines. Some or all of the signals may be multiplexed and sent over a single communication line.
[0024] Referring to FIG. 2 , a second exemplary control board embodiment 200 provides the ability to increase the distance of separation between local housing 102 and control board 106 . As shown in FIG. 1 and 2 , control board 106 is located remotely from the local housing 102 . Measurement chamber 104 , sample supply 110 , and vacuum system 112 are housed within local housing 102 . The details and operation of local housing 102 and its various components are described in the first exemplary control board embodiment 100 , set forth above. The second exemplary control board embodiment 200 provides amplifier 202 . Amplifier 202 may be used to amplify one or more of the signals sent to and from the various components of local housing 102 and control board 106 . For example, the measurement data signal may be amplified to increase the allowable distance between control board 106 and local housing 102 .
[0025] Amplifier 202 may include filters, buffers and other suitable signal processing components to amplify and clean the signals being transmitted. Amplifier 202 may be located at various points along transmission of the various signals. For example, amplifier 202 may be located within local housing 102 . In one preferred embodiment, the measurement data signal may be cleaned and amplified prior to transmission to control board 106 . Amplifier 202 may include components to convert the various signals and transmit such signals using known equipment and protocols to wirelessly transmit such signals via wireless channels of communication. For example, vacuum system 112 supplying a vacuum to measurement chamber 104 may be controlled remotely by sending control signals from control board 106 . This control signal may be amplified during transmission to increase the distance from measurement chamber 104 and control board 106 . It should also be noted that one skilled in the art will appreciate that a plurality of amplifiers may be incorporated in the embodiments described herein.
[0026] In other embodiments, some of the signal processing capabilities may remain in proximity to measurement chamber 104 so as to analyze, process, and store measurement data. In order to provide such local signal processing capabilities local housing 102 may further include the addition of at least a processor, a memory device, and a communications device capable of analyzing, processing, and storing measurement data along with the ability to transmit and receive signals to control board 106 .
[0027] FIG. 3 shows a flow chart illustrating an exemplary control board method embodiment 300 of the present invention. The administrator initiates the sample analysis by providing instructions to control board 106 (block 302 ). Vacuum system 112 provides a vacuum for measurement chamber 104 (block 304 ). Control board 106 signals a sample supply valve located within measurement chamber 104 to open. An amount of gaseous sample is supplied to measurement chamber 104 in gas form (block 306 ). The sample gas is ionized in measurement chamber 104 (block 308 ). A measurement data signal is detected from the ionized sample (block 310 ).
[0028] The measurement data signal is transmitted to control board 106 located in a remote location (block 312 ). The measurement data signal may be transmitted using a variety of methods as set forth herein. For example, the measurement data signal may be filtered and amplified. In another example, the measurement data signal may be converted to a wireless protocol and sent via a wireless channel to control board 106 . In yet another example, the measurement data signal may be transmitted in a filtered but un-amplified form to control board 106 . The extent or distance to which the components of local housing 102 and control board 106 can be placed apart depends upon the cabling and transmission characteristics.
[0029] Once control board 106 receives the measurement data-signal, control board 106 may analyze the measurement data signal at a location remote to local housing 102 (block 314 ). Control board 106 may analyze the measurement data signal by performing a Fourier Transformation on the measurement data signal. Performing the Fourier Transformation on the measurement data signal converts the measurement data signal from a time domain signal to a frequency domain signal. The frequency domain signal may be analyzed to determine the components and structure of the sample being analyzed. Control board 106 allows the administrator to manipulate, display, and store the measurement data at a remote location. The sample testing and analysis is complete for the above sample (block 316 ). Measurement chamber 104 may be cleaned and/or injected with a new sample for further testing. The above exemplary method that may be used in conjunction with other exemplary methods associated with other aspects of the invention. For example, control board 106 may also transmit control signals or receive sensor signals from the components of local housing 102 .
[0030] FIG. 4 shows an exemplary vacuum system embodiment 400 that provides for the ability to house vacuum system 112 and the control board 106 in a location remote from local housing 102 . In this embodiment, measurement chamber 106 and sample supply 110 are housed within local housing 102 . The details of the local housing and its various components are described in detail above. In this embodiment, piping, as described above, or other suitable material couples vacuum system 112 and measurement chamber 106 . The size, length, strength, and other characteristics of the piping or other material depend on the desired distance of separation between vacuum system 112 and measurement chamber 106 . In this embodiment, vacuum system 112 may generate a vacuum that is greater than is necessary at measurement chamber 104 to account for the distance between vacuum system 112 and measurement chamber 106 . One skilled in the art will appreciate that vacuum system 112 may be located in closer proximity to measurement chamber 104 than other remotely located components. As described above, control valves located at measurement chamber 104 may be controlled by control board 106 to regulate the vacuum produced in measurement chamber 104 .
[0031] FIG. 5 shows an exemplary sample supply embodiment 500 that provides for the ability to house sample supply 110 , vacuum system 112 , and control board 106 in remote housing 514 , which is remotely located from local housing 102 . Housing sample supply 110 , vacuum system 112 , and control board 106 in remote housing 514 allows for a portable and small local housing 102 . The details and operation of the various components set forth in this embodiment are described in detail above. In this embodiment, piping, as described above, or other suitable material couples sample supply 110 and vacuum system 112 to measurement chamber 106 . The size, length, strength, and other characteristics of the piping or other material depend on the desired distance of separation between local housing 102 and remote housing 514 . The environmental conditions necessary to maintain the sample in a gaseous state may also determine the characteristics of the piping used.
[0032] Thus, devices, systems, and methods that allow for distributed mass spectrometry are provided. Moreover, it will be understood that the foregoing is only illustrative of the principles of the invention, and that various modifications can be made by those skilled in the art without departing from the scope and spirit of the invention.
[0033] Persons skilled in the art will appreciate that the present invention can be practiced by other than the described embodiments, which are presented for purposes of illustration rather than of limitation, and the present invention is limited only by the claims that follow.
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A system, method, and device for providing remote mass spectrometry are disclosed. The exemplary system may have an ion source for injecting ions and a measurement chamber. The measurement chamber may be coupled to the ion source for receiving and detecting signals of the ions. The measurement chamber may have an analysis cell, a magnet and an ionizing device. A control board may be in communication with the measurement chamber. The control board may receive signals received and detected by the measurement chamber. The control board may be located remotely and may have a processor for analyzing the signal.
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CROSS-REFERENCE TO RELATED APPLICATIONS
The present application is a continuation of U.S. patent application Ser. No. 12/620,996, filed Nov. 18, 2009, now U.S. Pat. No. 7,986,132 which is a continuation of International patent application PCT/EP2008/055794 filed on May 12, 2008, which designates the United States and claims the benefit under 35 U.S.C. §119(e) of the U.S. Provisional Patent Application Ser. No. 60/924,536 filed on May 18, 2007. The content of all prior applications is incorporated herein by reference.
FIELD OF THE INVENTION
The present invention relates generally to static var compensator apparatuses, and more particularly to how static var compensator apparatus are connected to transmission grids.
BACKGROUND OF THE INVENTION
Shunt compensators are used in high voltage networks to compensate for excessive reactive power consumption or generation. Thyristors are often used to allow control of the exchanged reactive power of such shunt compensators on a per cycle basis.
A conventional way of connecting shunt compensators can be seen in FIG. 1 . An interfacing transformer 101 is used between the transmission grid 102 and the thyristor controlled/switched reactive power elements, to adapt the rated high voltage of the transmission system to a lower voltage in the range 10-30 kV to which Thyristor Controlled Reactors (TCR) 103 , Thyristor Switched Reactors (TSR) 103 and/or Thyristor Switched Capacitors (TSC) 104 are connected. Typically also shunt banks and/or harmonic filters 105 will be connected to the same low-voltage bus.
However, the connection of the prior art exhibits some drawbacks with respect to performance, such as transformer saturation at high capacitive delivery or at high grid voltage, reactive power consumption in the transformer and excessive rated secondary currents and very high short-circuit currents.
Consequently, there is a need to improve the use of shunt compensators in view of the prior art.
SUMMARY OF THE INVENTION
An object of the present invention is to simplify the arrangement related to static var compensators.
According to the invention there is provided a one-phase static var compensator apparatus. The apparatus comprises a compensator string consisting of a first static var compensator connected serially to a thyristor valve. The compensator string is arranged to be connected on its first end to one phase of a transmission grid of a rated voltage exceeding 69 kV. Moreover, the thyristor valve comprises a plurality of thyristors connected serially. The compensator string comprises a capacitor connected in parallel to said thyristor valve, and the compensator string is arranged to be directly galvanically connected to the transmission grid.
By connecting the compensator string directly to the transmission grid, or grid, the transformer is omitted. This is made possible by the inclusion of the capacitor, providing protection from voltage surges, for example from lightning strikes. The capacitor can be connected in parallel to the entire thyristor valve, or each thyristor of the thyristor valve can have a corresponding capacitor connected in parallel. Not having a transformer provides a number of advantages, such as no acoustical noise from transformer, and more environmentally friendly oil-free installation without the need to have oil containment arrangements. Moreover, civil work at site is simplified. Other disadvantages related to transformers can be avoided, such as the need for heavy transformer transports, long delivery times for transformers, long repair time after damage, high costs (which are likely to increase with time), and upgrading (in terms of increasing the var range) of the compensator may be difficult because of transformer rating.
In this context, a thyristor valve is to be construed as a plurality of thyristors connected in series.
The first static var compensator of the compensator string may be arranged to be directly connected to the transmission grid.
The thyristor valve may comprise one hundred thyristors connected serially.
The thyristor valve may comprise bidirectional controlled thyristors.
The first static var compensator may comprise an inductor.
The compensator string may further comprise a second static var compensator, and the thyristor valve may be connected on its first end to the first static var compensator and the thyristor valve may be connected on its second end to a first end of the second static var compensator.
The second static var compensator may comprise an inductor.
The second static var compensator may comprise a capacitor.
A second aspect of the invention is a three-phase static var compensator apparatus comprising three one-phase apparatuses according to the first aspect, wherein each of the one-phase apparatuses is arranged to be connected to a respective one phase of a three phase transmission grid.
The compensator string may be arranged to be connected on its first end to the respective phase and on its second end to a transmission grid associated with a different phase than the respective phase, thus forming a delta connection.
The compensator string may be arranged to be connected on its first end to the respective phase and on its second end to a neutral point, thus forming a wye-connection. The number of semiconductor devices in wye-connection is significantly lower than if delta-connection for the full transmission network voltage would have been used.
The neutral point may be connected to a transmission grid.
The neutral may be provided using an artificial neutral from a z-transformer connected to the three respective phases.
A third aspect of the invention is a three-phase static var compensator apparatus comprising: two one-phase apparatuses according to the first aspect, wherein each of the two one-phase apparatuses is arranged to be connected on its respective first end to a respective one phase of two phases of a three phase transmission grid, and a static var compensator arranged to be connected on its first end to a third phase of the three phase transmission grid. Second ends of the two one-phase apparatuses are both directly connected to a second end of the third static var compensator.
A fourth aspect of the invention is a one-phase static var compensator apparatus comprising: a compensator string consisting of a first static var compensator connected serially to a thyristor valve. The compensator string is arranged to be connected on its first end to one phase of a transmission grid of a rated voltage exceeding 69 kV. The thyristor valve comprises a plurality of thyristors connected serially, the compensator string comprises a capacitor connected in parallel to the thyristor valve, and the compensator string comprises an autotransformer arranged to galvanically connect the compensator string to the transmission grid.
It is to be noted that any feature of the first aspect, second aspect, third aspect or third aspect may be applied to any other aspect, where appropriate.
Generally, all terms used in the claims are to be interpreted according to their ordinary meaning in the technical field, unless explicitly defined otherwise herein. All references to “a/an/the element, device, component, means, step, etc.” are to be interpreted openly as referring to at least one instance of the element, device, component, means, step, etc., unless explicitly stated otherwise. The steps of any method disclosed herein do not have to be performed in the exact order disclosed, unless explicitly stated.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is now described, by way of example, with reference to the accompanying drawings, in which:
FIG. 1 is a schematic diagram illustrating a typical static var compensation for network reactive power compensation,
FIGS. 2 a - b are schematic diagrams illustrating delta-connected static var compensation using thyristor controlled reactors and thyristor controlled capacitors, respectively,
FIG. 2 c is a schematic diagram illustrating an alternative embodiment for the thyristor valve where a capacitor connected in parallel with each thyristor,
FIG. 3 is a schematic diagram illustrating a basic insulation level test arrangement,
FIG. 4 is a schematic diagram illustrating static var compensation with a wye-connection without a neutral connection,
FIG. 5 is a schematic diagram illustrating static var compensation connected through an autotransformer,
FIG. 6 is a schematic diagram illustrating static var compensation with autotransformer wye-connection with a neutral connection,
FIG. 7 is a schematic diagram illustrating static var compensation with a wye-connection and a Z-transformer,
FIG. 8 is a schematic diagram illustrating a stack of bidirectional phase controlled thyristors, and
FIG. 9 is a schematic diagram illustrating a valve with individual heat exchanger.
DETAILED DESCRIPTION OF THE INVENTION
The present invention will now be described more fully hereinafter with reference to the accompanying drawings, in which certain embodiments of the invention are shown. This invention may, however, be embodied in many different forms and should not be construed as limited to the embodiments set forth herein; rather, these embodiments are provided by way of example so that this disclosure will be thorough and complete, and will fully convey the scope of the invention to those skilled in the art. Like numbers refer to like elements throughout the description.
FIGS. 2 a - b are schematic diagrams illustrating delta-connected static var compensation using thyristor controlled reactors and thyristor controlled capacitors, respectively. In FIG. 2 a thyristor controlled reactors (TCR/TSRs) are connected in a delta-connection between the phases, in a three phase static var compensator apparatus 240 . The inductors 210 a ′ & 210 a ″, 210 b ′ & 210 b ″, 210 c ′ & 210 c ″, can be split in two parts 210 a ′ & 210 a ″, 210 b ′ & 210 b ″, 210 c ′ & 210 c ″ that are connected so that they are embedding the thyristor valve 212 a - c . Optionally one inductor within each pair can be omitted. Each respective serial connection line of inductors 210 a ′- c ′, 210 a ″- c ″ and thyristor valve 212 a - c is called a compensator string 211 a - c . In FIG. 2 b showing Thyristor Switched Capacitors (TSCs), the thyristor valve 212 a - c is normally inserted between a damping inductor 214 a - c and a capacitor bank 216 a - c as shown in FIG. 2 b . Each respective serial connection line of inductors 214 a ′- c ′, thyristor valve 212 a - c , and capacitor bank 216 a - c is called a compensator string 213 a - c . FIG. 2 c is an alternative embodiment illustrating the thyristor valve 212 a - c including a capacitor connected in parallel with each thyristor.
In an alternative embodiment, the thyristor valves 212 a - c are connected to the transmission grid, and the inductors and/or capacitors are in turn connected to the thyristor valves.
FIG. 3 is a schematic diagram illustrating a basic insulation level test arrangement.
The SVC installation switchyard typically will be protected against direct lightning strokes by protective wires above the equipment or with high grounded masts. Therefore lightning strokes can not hit the point between the thyristor valve and the reactor but will be taken up by the combined reactor-thyristor valve string (TCR or TSR) or the combined reactor-thyristor valve-capacitor bank string (TSC). Accordingly the string design shall incorporate means to suppress and/or control steep voltage surges such that full basic insulation level (BIL) test voltage can be applied across the strings just mentioned and shown in FIGS. 2 a and 2 b . An example for thyristor controlled reactor is shown in FIG. 3 . A test voltage generator 322 provides the voltage for the testing.
Special thyristor valve protective circuits may be required in order to fulfil this purpose. In FIG. 3 this has been indicated as a capacitor 320 connected in parallel with the thyristor pair 312 . In a real implementation additional components may be necessary in order to protect the thyristor turn-on process as is well known for those skilled in the power electronics.
In this case the thyristor valves have to be designed for the full line-line voltage of the transmission networks. The current most often is moderate. Due to the high voltage a large number of components can be series-connected in the valve.
The third harmonic current produced by the compensator string 211 a - c , will be included in the inductor current but captured and circulated within the delta-connection.
FIG. 4 is a schematic diagram illustrating static var compensation with a wye-connection without a neutral connection.
In principle also an SVC 440 with wye-connected strings of passive components (inductors and/or capacitor banks) 410 a - c and thyristor valves 412 a - b can be utilized. If the SVC does not operate with continuous control using phase-angle control but rather operates in a switching mode (fully on/fully off) only two valves 412 a - b are required as shown in FIG. 4 .
FIG. 5 is a schematic diagram illustrating static var compensation connected through an autotransformer, which will now be described.
One way to reduce the transformer rating is to utilize an auto-transformer 528 as an interface to an SVC 530 . FIG. 5 depicts the concept.
The rated power of the transformer is only a fraction of the total SVC power rating. If U 2 represents the voltage of the transmission grid 532 and U 1 represents the voltage of a SVC bus 534 , then an apparent power S trafo can be expressed as a factor of an apparent power of the SVC S SVC , as follows:
S
trafo
=
(
1
-
U
2
U
1
)
S
SVC
The autotransformer 528 leakage reactance is much lower than the leakage reactance in a transformer for the full SVC rating. This is often an advantage but in some cases it might be difficult to design the harmonic filters. If this is the case it might be advantageous to insert an extra inductor 526 in series with the autotransformer 528 as shown in FIG. 5 . The extra inductor 526 can also be used to lower the voltage stress across the thyristor valve at BIL voltage test.
If the transmission system has a neutral from the transformer it is possible to utilize an SVC 630 in wye-connection as shown in FIG. 6 . The figure shows a TCR but the SVC configuration 530 may include several TCRs, TSRs, TSCs and filter banks.
In this case the third harmonic current will pass through the autotransformer 628 neutral connection 636 .
Like in the preceding cases an extra inductor may be connected (not shown in FIG. 6 ) between the autotransformer and the SVC in order to lower the voltage stress across the thyristor valves at BIL surge voltage tests.
FIG. 7 is a schematic diagram illustrating static var compensation with a wye-connection and a Z-transformer. The Z-connected transformer 740 may be utilized to create a local neutral point (artificial neutral) for the voltages in the transmission system. Then a wye-connected thyristor valve of an SVC 740 may be utilized as outlined in FIG. 7 . The number of semiconductor devices in wye-connection is significantly lower than if delta-connection for the full transmission network voltage would have been used. Within the SVC 740 there are three compensator strings 711 a - c . The figure shows a generic string but the SVC configuration 740 may include several TCRs, TSRs, TSCs and filter banks.
The Z-transformer should be designed to let the third harmonic current pass through the transformer. No third harmonic voltage will be generated.
FIG. 8 is a schematic diagram illustrating a stack of bidirectional phase controlled thyristors.
Thyristors having a substantial current handling capability as compared to the normal rated current are available because only low current will be needed at the high rated voltage. This has some interesting implications. Firstly, the junction temperature can be kept close to the case temperature. Secondly, less design problems occur related to surge currents at failures or control errors. And thirdly, it is easy to design for a high overload capability for the SVC.
For this application, so called bidirectional thyristors or bidirectional controlled thyristors (BCT) 850 can be advantageously utilized. These devices have two anti-parallel thyristors integrated on the same silicon wafer. Only one stack of devices then is necessary for each valve function. Between each BCT 850 there is a cooling device 852 .
Most apparatus for voltages above 69 kV are designed for outdoor use. This is also a possibility for the thyristor valves mentioned herein. Each valve function contains one stack of (bidirectional) thyristors 850 . The stack can be put in an insulating enclosure 854 , e.g. formed by polymeric material, with sufficient flashing and creepage distance. FIG. 8 depicts this approach.
FIG. 9 is a schematic diagram illustrating a valve with individual heat exchanger.
In high voltage SVC valves the rated current becomes moderate and the loss per device is low as compared to conventionally used low-voltage designs. Therefore the temperature drop between junction and case 854 is low and a high temperature of the coolant may be used. This makes the heat-exchanger 956 smaller for a given total amount of power to be treated.
In an innovative design, each valve, which can include a stack of BCTs, has its own cooler either with a separate circulation pump 958 and/or with natural flow 960 of the coolant. FIG. 9 depicts this concept.
Regarding valve erection, the thyristor valves for high voltage become quite long as the number of series-connected devices becomes large (in the range of one hundred devices). Accordingly, it is reasonable to mount such valves hanging from the roof (indoors) or from a steel structure (outdoors).
The invention has mainly been described above with reference to a few embodiments. However, as is readily appreciated by a person skilled in the art, other embodiments than the ones disclosed above are equally possible within the scope of the invention, as defined by the appended patent claims.
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A one-phase static var compensator apparatus includes a compensator string consisting of a first static var compensator connected serially to a thyristor valve. The compensator string is arranged to be connected on its first end to one phase of a transmission grid of a rated voltage exceeding 69 kV. Moreover, the thyristor valve includes a plurality of thyristors connected serially and the compensator string is arranged to be directly connected to the transmission grid. A corresponding three phase apparatus is also presented.
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BACKGROUND OF THE INVENTION
[0001] The present invention relates generally to image generating systems including a reflective type, ferroelectric liquid crystal (FLC) spatial light modulator (SLM). More specifically, the invention relates to an optics arrangement including an FLC compensator cell for allowing the system to generate a substantially continuously viewable image while DC-balancing the FLC material of both the SLM and the compensator cell.
[0002] FLC materials may be used to provide a low voltage, low power reflective spatial light modulator due to their switching stability and their high birefringence. However, a problem with FLC materials, and nematic liquid crystal materials, is that the liquid crystal material may degrade over time if the material is subjected to an unbalanced DC electric field for an extended period of time. In order to prevent this degradation, liquid crystal spatial light modulators (SLMs) must be DC field-balanced.
[0003] Nematic liquid crystal materials respond to positive or negative voltages in a similar manner regardless of the sign of the voltage. Therefore, nematic liquid crystals are typically switched ON by applying either a positive or negative voltage through the liquid crystal material. Nematic liquid crystal materials are typically switched OFF by not applying any voltage through the material. Because nematic liquid crystal materials respond to voltages of either sign in a similar manner, DC balancing for nematic liquid crystal materials may be accomplished by simply applying an AC signal to create the voltage through the material. The use of an AC signal automatically DC balances the electric field created through the liquid crystal material by regularly reversing the direction of the electric field created through the liquid crystal material at the frequency of the AC signal.
[0004] In the case of FLC materials, the materials are switched to one state (i.e. ON) by applying a particular voltage through the material (i.e. +5 VDC) and switched to the other state (i.e. OFF) by applying a different voltage through the material (i.e. −5 VDC). Because FLC materials respond differently to positive and negative voltages, they cannot be DC-balanced in situations where it is desired to vary the ratio of ON time to OFF time arbitrarily. Therefore, DC field-balancing for FLC SLMs is most often accomplished by displaying a frame of image data for a certain period of time, and then displaying a frame of the inverse image data for an equal period of time in order to obtain an average DC field of zero for each pixel making up the SLMs.
[0005] In the case of an image generating system or display, the image produced by the SLM during the time in which the frame is inverted for purposes of DC field-balancing may not typically be viewed. If the system is viewed during the inverted time without correcting for the inversion of the image, the image would be distorted. In the case in which the image is inverted at a frequency faster than the critical flicker rate of the human eye, the overall image would be completely washed out and all of the pixels would appear to be half on. In the case in which the image is inverted at a frequency slower than the critical clicker rate of the human eye, the viewer would see the image switching between the positive image and the inverted image. Neither of these situations would provide a usable display.
[0006] In one approach to solving this problem, the light source used to illuminated the SLM is switched off or directed away from the SLM during the time when the frame is inverted. This type of system is described in copending U.S. patent application Ser. No. 08-361,775, filed Dec. 22, 1994, entitled DC FIELD-BALANCING TECHNIQUE FOR AN ACTIVE MATRIX LIQUID CRYSTAL IMAGE GENERATOR, which is incorporated herein by reference. However, this approach substantially limits the brightness and efficiency of the system. In the case where magnitude of the electric field during the DC field-balancing and the time when the frame is inverted is equal to the magnitude of the electric field and the time when the frame is viewed, only a maximum of 50% of the light from a given light source may be utilized. This is illustrated in FIG. 1 a which is a timing diagram showing the relationship between the switching on and off of the light source and the switching of the SLM image data.
[0007] As shown in FIG. 1 a , the light source is switched on for a period of time indicated by T 1 . During this time T 1 , the SLM is switched to form a desired image. In order to DC balance the SLM, the SLM is switched to form the inverse of the desired image during a time period T 2 . In order to prevent this inverse image from distorting the desired image, the light source is switched off during the time T 2 as shown in FIG. 1 a.
[0008] In order to establish a convention to be used throughout this description, the operation of a given pixel 10 of a reflective type FLC SLM using the above mentioned approach of switching off the light source during the time the frame is inverted will be described with reference to FIGS. 1 b - d . FIG. 1 b shows pixel 10 when it is in its bright state and FIG. 1 c shows pixel 10 when it is in its dark state. As illustrated in both FIGS. 1 b and 1 c , a light source 12 directs light, indicated by arrow 14 , into a polarizer 16 . Polarizer 16 is arranged to allow, for example, horizontally linearly polorized light, indicated by the reference letter H and by arrow 18 , to pass through polarizer 16 . However, polarizer 16 blocks any vertically linearly polarized component of the light and thereby directs only horizontally linearly polarized light into pixel 10 . This arrangement insures that only horizontally linearly polarized light is used to illuminate pixel 10 . For purposes of clarity throughout this description, the various configurations will be described using horizontally linearly polarized light as the initial input light for each of the various configurations.
[0009] As also illustrated in FIGS. 1 b and 1 c , pixel 10 includes a reflective backplane 22 and a layer of FLC material 24 which is supported in front of reflective backplane 22 and which acts as the light modulating medium. The various components would typically be positioned adjacent one another, however, for illustrative purposes, the spacing between the various components is provided. In this example, the FLC material has a thickness and a birefringence which cause the material to act as a quarter wave plate for a given wavelength. In this example, the FLC material is typical of those readily available and has a birefringence of 0.142. Therefore a thickness of 900 nm causes the SLM to act as a quarter wave plate for a wavelength of approximately 510 nm.
[0010] FLC material 22 has accompanying alignment layers (not shown) at the surfaces which have a buff axis or alignment axis that controls the alignment of the molecules of the FLC material. For this example of a reflective mode SLM, the SLM is oriented such that the alignment axis is rotated 22.5 degrees relative to the polarization of the horizontally linearly polarized light being directed into the SLM. The FLC also has a tilt angle of 22.5 degrees associated with the average optic axis of the molecules making up the FLC material. Therefore, when FLC material 24 of the pixel is switched to its first state, in this case by applying a +5 VDC electric field across the pixel, the optic axis is rotated to a 45 degree angle relative to the horizontally linearly polarized light. This causes the pixel to act as a quarter wave plate for horizontally linearly polarized light at 510 nm. Alternatively, when the pixel is switched to its second state, in this case by applying a −5 VDC electric field across the pixel, the optic axis is rotated to a zero degree angle relative to the horizontally linearly polarized light. This causes the pixel to have no effect on the horizontally linearly polarized light directed into the pixel. In other words, the tilt angle is the angle that the FLC optic axis is rotated one side or the other of the buff axis when the FLC material is switched to its first and second states.
[0011] Now that the configuration of the pixel for this example has been described, its effect on the light as it passes through the various elements will be described. Initially, it will be assumed the light is monochrome at the wavelength at which the SLM acts as a quarter wave plate, in this case 510 nm. As illustrated in FIG. 1 b , when the FLC material is switched to its first state, which will be referred to hereinafter as its A state, FLC material 24 converts the 510 nm wavelength horizontally linearly polarized light directed into the pixel and indicated by arrow 18 into circularly polarized light indicated by the reference letters C and arrow 26 . Reflective backplane 22 reflects this circularly polarized light as indicated by arrow 28 and directing it back into FLC material 24 . FLC material 24 again acts on the light converting it from circularly polarized light to vertically linearly polarized light as indicated by reference letter V and arrow 30 . The vertically linearly polarized light 30 is directed into an analyzer 32 which is configured to pass vertically linearly polarized light and block horizontally polarized light. Since analyzer 32 is arranged to pass vertically linearly polarized light, this vertically linearly polarized light indicated by arrow 30 passes through analyzer 32 to a viewing area indicated by viewer 34 causing the pixel to appear bright to the viewer.
[0012] Alternatively, as illustrated in FIG. 1 c, FLC material 24 has no effect on the horizontally linearly polarized light directed into the pixel when the pixel is in its second state, which will be referred to hereinafter as its B state. This is the case regardless of the wavelength of the light. Therefore, the horizontally linearly polarized light passes through FLC material 24 and is reflected by reflective backplane 22 back into FLC material 24 . Again, FLC material 24 has no effect on the horizontally linearly polarized light. And finally, since analyzer 32 is arranged to block horizontally linearly polarized light, the horizontally linearly polarized light is prevented from passing through to viewing area 34 causing the pixel to appear dark.
[0013] Although the polarization state of the light is relatively straight forward when the light is assumed to be at a wavelength at which the SLM acts as a quarter wave plate, it becomes more complicated when polychromatic light is used. This is because even if the birefringence An of the FLC were constant, the retardance of the SLM in waves would vary with wavelength; furthermore, the birefringence of the FLC material also varies as the wavelength of the light varies. In display applications, this becomes very important due to the desire to provide color displays. FIG. 1 d illustrates the effects the SLM has on visible light ranging in wavelength from 400 nm to 700 nm as a function of the wavelength of the light assuming typical FLC birefringence dispersions. Solid line 36 corresponds to the first case when the pixel is in its A state as illustrated in FIG. 1 b and the dashed line 38 corresponds to the second case when the pixel is in its B state as illustrated in FIG. 1 c. As is illustrated in FIG. 1 d , the resulting output of this configuration varies substantially depending on the wavelength of the light as indicated by line 36 . In fact, only a little more than 50% of the horizontally linearly polarized light at 400 nm that is directed into the SLM is converted to vertically linearly polarized light using this configuration.
[0014] The above described configuration makes use of crossed polarizers. That is, polarizer 16 blocks vertically linearly polarized light and analyzer 32 blocks horizontally linearly polarized light. This means that polarizer 16 and analyzer 32 must be different elements. If both polarizer 16 and analyzer 32 were configured to pass the same polarization of light, they would be referred to as parallel polarizers and could be provided by the same element.
[0015] In an alternative system configuration, a polarizing beam splitter may be used to replace both the polarizer and the analyzer. FIGS. 1 e and 1 f illustrate such a system when pixel 10 is in its A and B states respectively. In this alternative system, light from light source 12 is directed into a polarizing beam splitter (PBS) 40 as indicated by arrow 42 . PBS 40 is configured to reflect horizontally linearly polarized light as indicated by arrow 44 and pass vertically linearly polarized light as indicated by arrow 46 . The horizontally linearly polarized light indicated by arrow 44 is directed into SLM 24 .
[0016] When pixel 10 is in its A state as illustrated in FIG. 1 e , SLM 24 acts as a quarter wave plate as described above converting the horizontally linearly polarized light to circularly polarized light and reflective backplane 22 reflects this light back into SLM 24 . Again, SLM 24 converts this circularly polarized light into vertically linearly polarized light as described above for FIG. 1 b and as indicated by arrow 48 . Since PBS 40 is configured to pass vertically linearly polarized light, this light passes through PBS 40 into viewing area 34 causing pixel 10 to appear bright.
[0017] When pixel 10 is in its B state as illustrated in FIG. 1 f , SLM 24 has no effect on the horizontally linearly polorized light. Therefore, the horizontally linearly polarized light that is directed into SLM 24 as indicated by arrow 44 remains horizontally linearly polarized light as it passes through SLM 24 , is reflected by backplane 22 , and again passes through SLM 24 . However, since PBS 40 is configured to reflect horizontally linearly polarized light, this light is reflected back toward light source 12 as indicated by arrow 50 causing pixel 10 to appear dark.
[0018] As mentioned above, in the configuration currently being described, the light source is turned off during the time in which the image is inverted for purposes of DC field-balancing the FLC material as illustrated in FIG. 1 a . This substantially reduces the brightness or efficiency of the display. In order to overcome this problem of not being able to view the system during the DC field-balancing frame inversion time, compensator cells have been proposed for transmissive SLMs such as those described in U.S. Pat. No. 5,126,864. These compensator cells are intended to correct for the frame inversion during the time when the FLC pixel is being operated in its inverted state. FIG. 2 a illustrates a transmissive mode system 200 which includes an SLM 202 , a compensator cell 204 , a polarizer 206 , and an analyzer 208 .
[0019] As described above for the FLC material of the SLM of the previous configuration, SLM 202 and compensator cell 204 each include an FLC layer which is switchable between an A and a B state. This results in four possible combinations of states for the SLM and compensator cell. For purposes of consistency in comparing various configurations described herein, these four cases will be defined as follows:
[0020] Case 1 —compensator cell in B state, SLM pixel in A state
[0021] Case 2 —compensator cell in B state, SLM pixel in B state
[0022] Case 3 —compensator cell in A state, SLM pixel in B state
[0023] Case 4 —compensator cell in A state, SLM pixel in A state
[0024] For this configuration, Cases 1 and 2 correspond to the normal operation of the system during which the compensator cell is in its B state and the SLM pixels are switched between their A and B states to respectively produce a bright or dark pixel. This is illustrated in the first half of FIG. 2 b which is a timing diagram showing the states of the light source, the SLM, and the compensator cell. As shown in FIG. 2 b , the light source remains ON throughout the operation of the system. During the first half of the time illustrated in FIG. 2 b , the pixels of the SLM are switched between their A and B states to produce a desired image. Cases 3 and 4 correspond to the time during which the frame is inverted for purposes of DC field balancing (i.e. the SLM pixel states must be reversed) and the compensator cell is switched to its A state to compensate for the inversion. This is illustrated by the second half of the diagram of FIG. 2 b . To properly DC field-balance the display as well as allow the display to be viewed continuously, Case 1 and Case 3 must give the same results and Case 2 and Case 4 must give the same results. That is, for this configuration, Cases 1 and 3 must both produce a bright pixel and Cases 2 and 4 must both produce a dark pixel.
[0025] In this example of a transmissive mode system, both the FLC layer of the SLM pixel and the compensator cell are 1800 nm thick which causes them to act as a half wave plate for a wavelength of 510 nm when in the ON state. In this configuration, the polarizer and analyzer perform the functions performed by polarizer 16 and analyzer 32 , or alternatively PBS 40 , of the reflective mode systems described above. Polarizer 206 is positioned optically in front of compensator cell 204 and the SLM pixel 202 such that it allows only horizontally linearly polarized light to pass through it into compensator cell 204 . Also, analyzer 208 which only allows vertically linearly polarized light to pass through is positioned optically behind SLM 202 .
[0026] [0026]FIGS. 2 c and 2 d illustrate the net result the above described transmissive system configuration has on light directed in to the system. FIG. 2 c shows the results for Case 1 and 2 during which the compensator cell is in its B state and the SLM is switched between its A state for Case 1 and its B state for Case 2 . Case 1 is indicated by solid line 210 and Case 2 is indicated by dashed line 212 . FIG. 2 d shows the results for Case 3 and 4 during which the compensator cell is in its A state and the SLM is switched between its B state for Case 3 and its A state for Case 4 . Case 3 is represented by solid line 214 and Case 4 is represented by dashed line 216 .
[0027] As clearly shown by FIGS. 2 c and 2 d , this transmissive configuration produces identical results, that is a bright pixel, for Case 1 and 3 as indicated by lines 210 and 214 , respectively. It also produces identical results for Cases 2 and 4 as indicated by lines 212 and 216 , respectively. It should also be noted that this configuration produces relatively good results over the entire wavelength range from 400 nm to 700 nm. The worst results are at 400 nm where approximately 80% of the horizontally linearly polarized light is converted to vertically polarized light.
[0028] Although the compensator cell approach works well for a transmissive SLM as described above, applicant has found that this same general approach does not work as well for a reflective type SLM. To illustrate this difference, and referring to FIG. 3 a , a reflective type display system 300 including a reflective type SLM 302 having a reflective backplane 303 , a compensator cell 304 , a polarizer 306 , and an analyzer 308 will be described. Compensator cell 304 is positioned adjacent to SLM 302 . As described above for FIGS 1 b and 1 c , polarizer 306 is positioned to direct only horizontally linearly polarized light into compensator cell 304 . Because the light passes through the SLM and the compensator cell twice in a reflective mode system, the FLC material of SLM 302 and compensator cell 304 are configured to act as quarter wave plates for a wavelength of 510 nm rather than half wave plates as described above for the transmissive system of FIG. 2 a.
[0029] In this example, the FLC materials of both SLM 302 and compensator cell 304 are 900 nm thick and both have a tilt angle of 22.5 degrees. The buff axis of the SLM is aligned with the horizontally linearly polarized light directed into the system by polarizer 306 . Also, the buff axis of compensator cell 304 is positioned perpendicular to the buff axis of SLM 302 . FIGS. 3 b and 3 c illustrate the net result that system 300 has on light directed in to the system. FIG. 3 b shows the results for Case 1 and 2 during which the compensator cell is in its B state and the SLM is switched between its A state for Case 1 and its B state for Case 2 . Case 1 is indicated by solid line 310 and Case 2 is indicated by dashed line 312 . FIG. 3 c shows the results for Case 3 and 4 during which the compensator cell is in its A state and the SLM is switched between its B state for Case 3 and its A state for Case 4 . Case 3 is represented by solid line 314 and Case 4 is represented by dashed line 316 .
[0030] As clearly shown by FIGS. 3 b and 3 c , system 300 produces identical results, that is, a bright pixel for Case 1 and 3 as indicated by lines 310 and 314 , respectively. It also produces identical results for Cases 2 and 4 as indicated by lines 312 and 316 , respectively. However, this configuration does not produces very good results over the entire wavelength range from 400 nm to 700 nm. The worst results are at 400 nm where only approximately 5% of the horizontally linearly polarized light is converted to vertically polarized light. At a wavelength of about 500 nm about 50% of the horizontally linearly polarized light is converted to vertically linearly polarized light. The best results are at 700 nm where about 80% of the horizontally linearly polarized light is converted to vertically linearly polarized light. Since the point to adding the compensator cell is to increase the efficiency or brightness of the system, this arrangement does not improve the efficiency or brightness for the lower wavelength range when compared to the system of FIG. 1 b and 1 c which simply turns OFF the light source during the DC field-balancing time.
[0031] As can be clearly seen when comparing FIGS. 3 b - c to FIGS. 2 c - d , the effects on the light caused by the various components of the reflective configuration of FIG. 3 a are very much different from the effects on the light caused by the transmissive configuration of FIG. 2 a . That is, the reflective configuration of FIG. 3 a is not optically equivalent to the transmissive configuration of FIG. 2 a even though it may initially seem as though they should be optically equivalent. These two configurations are optically different from one another because the light must pass through the SLM and compensator cell twice in the reflective configuration with the first pass through the compensator being before the two passes through the SLM and the second pass through the compensator cell being after the two passes through the SLM.
[0032] Due to this difference in the transmissive and reflective configurations, it has proved difficult to provide a reflective type system which is DC field-balanced and is substantially continuously viewable while providing improved efficiency or brightness compared to a system which simply turns off the light source during the DC field-balancing portion of the frame. The present invention provides arrangements and methods for overcome this problem.
SUMMARY OF THE INVENTION
[0033] As will be described in more detail hereinafter, a reflection mode, spatial light modulating system and methods of operating the system are herein disclosed. The reflection mode, ferroelectric liquid crystal spatial light modulating system, includes a light reflecting type spatial light modulator. The spatial light modulator has a light reflecting surface cooperating with a layer of ferroelectric liquid crystal light modulating medium switchable between first and second states so as to act on light in different first and second ways, respectively. A switching arrangement switches the liquid crystal light modulating medium between the first and second states and an illumination arrangement produces a source of light. An optics arrangement is optically coupled the spatial light modulator and the illumination arrangement such that light is directed from the source of light into the spatial light modulator for reflection back out of the modulator and such that reflected light is directed from the spatial light modulator into a predetermined viewing area. A compensator cell is also positioned in the optical path between the light source and the viewing area. The compensator cell has a layer of ferroelectric liquid crystal light modulating medium switchable between a primary and a secondary state so as to act on light in different primary and secondary ways, respectively.
[0034] In one embodiment, the optics arrangement includes a passive quarter wave plate positioned in the optical path between the light source and the spatial light modulator and in the optical path between the spatial light modulator and the viewing area. In this embodiment, the compensator cell is positioned in the optical path between the light source and the spatial light modulator and in the optical path between the spatial light modulator and the viewing area.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] The features of the present invention may best be understood by reference to the following description of the presently preferred embodiments together with the accompanying drawings.
[0036] [0036]FIG. 1 a is a timing diagram illustrating the timing at which a light source for a prior art DC-balanced display system is switched ON and OFF.
[0037] FIGS 1 b and 1 c are diagrammatic cross sectional views of a pixel of a prior art reflective type SLM display system illustrating how the pixel acts on light when the pixel is in the ON and OFF states.
[0038] [0038]FIG. 1 d is a graph illustrating the effects the system of FIG. 1 b and 1 c has on light after it passes through the system.
[0039] FIGS 1 e and 1 f are diagrammatic cross sectional views of a pixel of a prior art reflective type SLM display system including a polarizing beam splitter.
[0040] [0040]FIG. 2 a is a diagrammatic cross sectional view of a prior art transmissive SLM display system.
[0041] [0041]FIG. 2 b is a timing diagram illustrating the timing at which a light source for a prior art DC-balanced display system is switched ON and OFF.
[0042] [0042]FIGS. 2 c and 2 d are graphs illustrating the effects the system of FIG. 2a has on light after it passes through the system.
[0043] [0043]FIG. 3 a is a diagrammatic cross sectional view of a prior art reflective SLM display system.
[0044] [0044]FIGS. 3 b and 3 c are graphs illustrating the effects the system of FIG. 3 a has on light after it passes through the system.
[0045] [0045]FIG. 4 a is a diagrammatic cross sectional view of a first embodiment of a reflective SLM display system designed in accordance with the present invention.
[0046] [0046]FIGS. 4 b - c are graphs illustrating the effects the system of FIG. 4 a has on light after it passes through the system.
[0047] [0047]FIG. 5 a is a diagrammatic cross sectional view of a second embodiment of a reflective SLM display system designed in accordance with the present invention.
[0048] FIGS 5 b - c are graphs illustrating the effects the system of FIG. 5 a has on light after it passes through the system.
[0049] [0049]FIG. 5 is a diagrammatic cross sectional view of a third embodiment of a reflective SLM display system designed in accordance with the present invention.
[0050] [0050]FIGS. 7 a - b are diagrammatic cross sectional views of a fourth embodiment of a reflective SLM display system designed in accordance with the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0051] An invention is described for providing methods and apparatus for producing a substantially continuously viewable reflective type SLM display system which is DC field-balanced and which is more efficient or brighter than would be possible using a reflective type SLM display system which simply turns off the light source during the DC field balancing portion of each image frame. In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present invention. However, based on the following description, it will be obvious to one skilled in the art that the present invention may be embodied in a wide variety of specific configurations. Also, well known processes for producing various components and certain well known optical effects of various optical components will not be described in detail in order not to unnecessarily obscure the present invention.
[0052] Referring initially to FIG. 4 a , the present invention will be described with reference to a first embodiment of the invention which takes the form of a reflective type SLM display system generally designated by reference numeral 400 . As illustrated in FIG. 4 a , system 400 includes an SLM 402 having a reflective backplane 403 , a compensator cell 404 , a polarizer 405 , and an analyzer 406 . Alternatively, in the same manner as described above, crossed polarizer 405 and analyzer 406 may be replaced with a polarizing beam splitter.
[0053] System 400 is configured in a manner similar to that described above for system 300 of FIG. 3 a . That is, compensator cell 404 is positioned adjacent SLM 402 . Also, polarizer 405 is positioned to direct only horizontally linearly polarized light into compensator cell 404 . Similarly, analyzer 406 allows only vertically linearly polarized light to pass through it and into the viewing area after the light directed in to the system has passed through compensator cell 404 and SLM 402 and been reflected back through SLM 402 and compensator cell 404 . However, in accordance with the invention, system 400 also includes a static quarter wave plate 408 positioned optically between compensator cell 404 and polarizer 405 and analyzer 406 .
[0054] As would be understood by those skilled in the art, SLM 402 may be made up of an array of any number of individually controllable pixels which are individually switchable between two states. For purposes of consistency, it will be assumed that each pixel is switched to its A state by applying a +5 VDC electric field through the pixel and each pixel is switched to its B state by applying a −5 VDC electric field through the pixel. It should be understood that the present invention is not limited to these specific voltages and would equally apply regardless of the voltages used to switch the pixels.
[0055] System 400 further includes a light source 410 for directing light into the system in a manner similar to that described above for FIGS 1 b and 1 c . With this configuration, light source 410 directs light into polarizer 405 as indicated by arrow 412 . Polarizer 405 blocks any vertically linearly polarized portions of the light from passing through polarizer 405 an allows only horizontally linearly polarized portions of the light to pass through polarizer 405 into static quarter wave plate 408 . This light passes through static quarter wave plate 408 , compensator cell 404 , and SLM 402 and is then reflected by reflective backplane 403 back through SLM 402 , compensator cell 404 , and static wave plate 408 to analyzer 406 as illustrated in FIG. 4 a . Analyzer 406 then blocks any horizontally linearly polarized portions of the light and allows only vertically linearly polarized portions of the light to pass through it to a viewing area indicated by viewer 416 . Since polarizer 405 blocks vertically linearly polarized light and analyzer 406 blocks horizontally linearly polarized light, this type of system is referred to as using crossed polarizers.
[0056] For this embodiment and as described above for system 300 , because the light passes through the SLM and the compensator cell twice in a reflective mode system, the FLC material of SLM 402 and compensator cell 404 are configured to act as quarter wave plates for a wavelength of 510 nm. In this configuration, the FLC materials of both SLM 402 and compensator cell 404 are 900 nm thick and both have a tilt angle of 22.5 degrees. In this specific embodiment, the buff axis of the SLM is positioned at a 22.5 degree angle relative to the horizontally linearly polarized light directed into the system. Also, for this embodiment, the buff axis of compensator cell 404 is positioned perpendicular to the buff axis of SLM 402 .
[0057] Although the buff axis of the SLM is described as being positioned at 22.5 degrees relative to the horizontally linearly polarized light directed into the system, this is not a requirement. In fact, this configuration works equally as well regardless of the orientation of the SLM buff axis relative to the horizontally linearly polarized light directed into the system so long as the buff axis of the compensator cell is oriented perpendicular to the buff axis of the SLM. This freedom in orienting the buff axis of the SLM relative to the horizontally linearly polarized light directed into the system makes this overall system easier to produce than other conventional systems because only the orientation of the SLM relative to the compensator cell must be precisely controlled.
[0058] The orientation of the static quarter wave plate relative to the horizontally linearly polarized light directed into the system is also important. Generally, static quarter wave plate 408 has a primary axis which is oriented at a 45 degree angle to the horizontally linearly polarized light directed into the quarter wave plate.
[0059] Although the tilt angles of SLM 402 and compensator cell 404 are described as being 22.5 degrees, this is not a requirement. The configuration described above for this embodiment works regardless of the tilt angle of the FLC material of the SLM and the compensator cell, but works best when the tilt angles of the two components are the same. Therefore, it should be understood that the present invention would equally apply to systems using SLMs and compensator cells having tilt angles other than 22.5 degrees. With this configuration, the bright states obtained by the system remain bright regardless of the tilt angle used provided the tilt angles match. However, the use of tilt angles in the range of 22.5 to 25.5 degrees provides optimum dark state extinction, with the choice of tilt angle at the low end of the range providing best extinction over a narrow range of wavelengths centered on the wavelength for which the SLM and compensator have quarter-wave retardance and with the choice of tilt angle towards the upper end of the range providing good extinction over a more extended range of wavelength. Increasing the tilt angle past 25.5 degrees eventually reduces dark state extinction.
[0060] Now that the physical configuration of system 400 has been described, its effect on light directed into system 400 will be described. FIGS. 4 b and 4 c illustrate the net result that system 400 has on light directed in to the system. FIG. 4 b shows the results for Case 1 and 2 during which the compensator cell is in its B state and the SLM is switched between the A state for Case 1 and the B state for Case 2 . Case 1 is indicated by solid line 420 and Case 2 is indicated by dashed line 422 . FIG. 4 c shows the results for Case 3 and 4 during which the compensator cell is in its A state and the SLM is switched between the B state for Case 3 and the A state for Case 4 . Case 3 is represented by solid line 424 and Case 4 is represented by dashed line 426 . Cases 1 - 4 correspond to Cases 1 - 4 for the systems described above in the background.
[0061] As illustrated in FIGS. 4 b and 4 c , because of quarter wave plate 408 is included in the configuration of system 400 , Cases 1 and 3 result in a dark pixel rather than a bright pixel and Cases 2 and 4 result in a bright pixel rather than a dark pixel. This is the opposite of the results described in the background. However, this inversion of the bright and the dark states may be compensated for in a variety of ways such as reversing the A and the B states for the SLM (i.e. using a −5 VDC to switch the pixel to the A state and using a 5 VDC to switch the pixel to the B state). The important thing is that the results of Cases 1 and 3 are identical and the results of Cases 2 and 4 are identical.
[0062] For system 400 , static quarter wave plate 408 is preferably a readily providable achromatic quarter wave plate. The use of an achromatic static quarter wave plate provides the best results over a broad color spectrum because it flattens out the curves 422 of FIG. 4 b and 426 of FIG. 4 c representing the bright states obtained by Case 1 and Case 2 . This flattening out of the curve improves the optical throughput of system 400 by increasing the amount of light which passes through the system for a given pixel when the combination of that pixel and the other elements are switched to produce a bright state.
[0063] In one embodiment of the invention which reverses the bright and dark states described above for FIGS. 4 a - c , parallel polarizers are used instead of crossed polarizers. FIG. 5 a - c illustrate a system 500 which utilizes parallel polarizers. As described above for system 400 , system 500 includes a SLM 502 , a reflective backplane 503 , a compensator cell 504 , a polarizer 505 , a static quarter wave plate 508 , and a light source 510 . Light source 510 directs light into polarizer 505 which blocks any vertically linearly polarized light and allows only horizontally linearly polarized light to pass through. This horizontally linearly polarized light then passes through and is acted upon by static quarter wave plate 508 , compensator cell 504 , SLM 502 , and reflective backplane 503 in the same way as described above for FIG. 4 a . However, in this embodiment, polarizer 505 also acts as the analyzer for the system. This use of polarizer 505 for both the polarizer and the analyzer is what makes this system a parallel polarizer system.
[0064] In the configuration of FIG. 5 a , polarizer 505 acts as the analyzer by blocking any vertically linearly polarized light and allowing any horizontally linearly polarized light to pass into the viewing area. This is the opposite of the polarizations of light blocked and passed by analyzer 406 in system 400 . This has the effect of reversing the bright and dark states of the system and results in the net effects illustrated in FIGS. 5 b and 5 c . FIG. 5 b shows the results for Case 1 and 2 during which the compensator cell is in its B state and the SLM is switched between the A state for Case 1 and the B state for Case 2 . Case 1 is indicated by solid line 520 and Case 2 is indicated by dashed line 522 . FIG. 5 c shows the results for Case 3 and 4 during which the compensator cell is in its A state and the SLM is switched between the B state for Case 3 and the A state for Case 4 . Case 3 is represented by solid line 524 and Case 4 is represented by dashed line 526 . Cases 1 - 4 correspond to Cases 1 - 4 for the systems described above in the background and Cases 1 - 4 described above for FIG. 4.
[0065] As clearly shown by FIGS. 5 b and 5 c , system 500 produces identical results, that is, a bright pixel for Case 1 and 3 as indicated by lines 520 and 524 , respectively. It also produces identical results for Cases 2 and 4 as indicated by lines 522 and 526 , respectively. This configuration also produces very good results over the entire wavelength range from 400 nm to 700 nm. In fact, as illustrated by lines 522 and 526 , this configuration provides substantially uniform blockage of the entire range of wavelengths of the light that is directed into the spatial light modulator. Also, in both Cases 1 and 3 , a large portion of the horizontally linearly polarized light passes through the system for the entire range of 400 nm to 700 nm. Since the point to adding the compensator cell is to increase the efficiency or brightness of the system, this arrangement dramatically improves the efficiency or brightness of system 500 over the complete wavelength range when compared to the system of FIG. 1 b and 1 c which simply turns OFF the light source during the DC field-balancing time. This also substantially improves the efficiency of the system compared to system 300 of FIG. 3 described above which does not include the static quarter wave plate. Furthermore, since essentially no light from the light source passes through the system to the viewing area when the elements are switched to produce a dark state as indicated by lines 522 and 526 , this configuration also provides an excellent contrast ratio.
[0066] In another embodiment similar to system 400 of FIG. 4 a , a birefringent element may be added to system 400 in order to provide results very similar to the results obtained by system 500 of FIG. 5 a . Using like reference numerals to represent like components, FIG. 6 illustrates a system 600 including SLM 402 , reflective backplane 403 , compensator cell 404 , polarizer 405 , analyzer 406 , static quarter wave plate 408 , and light source 410 . As described above for FIG. 4, polarizer 405 and analyzer 406 are crossed polarizers. However, in accordance with this embodiment of the invention, system 600 further includes an additional birefringent element 612 which can be positioned between SLM 402 and compensator cell 404 , as shown here, or alternately, can be positioned between compensator cell 404 and static quarter wave plate 408 .
[0067] In this embodiment, birefringent element 612 is a commercially available polycarbonate film having a retardance of approximately one half of the wavelength of the light for which the system is optimized, for example a wavelength of 510 nm. Alternatively, birefringent element 612 may be any birefringent material capable of providing the desired retardance such as poly vinyl alcohol or any other optically clear birefringent material.
[0068] In this embodiment, the buff axes of SLM 402 and compensator cell 404 are parallel to one another and birefringent element 612 has a primary axis which is oriented perpendicular to the buff axis of both SLM 402 and compensator cell 404 . As describe above for system 400 , polarizer 405 directs horizontally linearly polarized light into quarter wave plate 408 and quarter wave plate 408 is oriented at a 45 degree angle to the horizontally linearly polarized light. SLM 402 , compensator cell 404 , and birefringent element 612 may be oriented in any way relative to quarter wave plate 408 so long as the buff axes of SLM 402 and Compensator cell 404 are parallel to one another and the primary axis of birefringent element 612 is perpendicular to the buff axes of SLM 402 and compensator cell 404 .
[0069] The addition of the birefringent element causes Case 1 and Case 3 for this embodiment to result in a bright state in which the throughput varies only slightly over the range of the wavelengths similar to curves 520 and 524 of FIGS. 5 b and 5 c . Also, the addition of the birefringent element causes Case 2 and Case 4 for this embodiment to result in a substantially more uniform dark state similar to lines 522 and 526 of FIGS. 5 b and 5 c . This results in a system that is able to provide a high contrast ratio while maintaining a relatively high throughput for the entire wavelength range even though crossed polarizers are utilized.
[0070] Although the above described embodiments have been described as having the static quarter wave plate positioned between the polarizer and the compensator cell, this is not a requirement. Instead, the static quarter wave plate may be located between the compensator cell and SLM and still remain within the scope of the invention.
[0071] In another embodiment, an off axis system may be utilized in order to provide a continuously viewable DC field-balanced reflective display system. FIGS. 7 a and 7 b illustrate one embodiment of an off axis display system 700 . As illustrated in FIGS. 7 a and 7 b , system 700 includes a SLM 702 , a reflective backplane 703 , a compensator cell 704 , a polarizer 705 , an analyzer 706 , and a light source 710 . In this embodiment, the light is directed into the SLM at an angle and reflected back into a viewing area indicated by viewer 720 such that the light directed into the system only passes through the compensator cell once rather than passing through the compensator cell twice as described above for the previously described embodiments.
[0072] Since the light only passes through compensator cell 704 once, the thickness of compensator cell 704 is configured to be twice the thickness of the SLM. Generally, SLM 702 has a thickness which causes SLM 702 to act as a quarter wave plate when switched to its A state and compensator cell 704 has a thickness which causes it to act as a half wave plate when it is switched to its A state. Therefore, in the case in which an FLC material is used for both the SLM and compensator cell that has a birefringence of 0.142, the thickness FLC material for the SLM would be approximately 900 nm and the thickness of the FLC material for the compensator cell would be approximately 1800 nm. Both SLM 702 and compensator cell are configured to have substantially no effect on the polarization of the light passing through them when they are switched to their B states.
[0073] For the configuration being described, polarizer 705 is configured to allow only horizontally linearly polarized light to be directed into the system. Analyzer 706 is configured to allow only vertically linearly polarized light to pass into the viewing area. Also, for this embodiment, the buff axis of compensator cell 704 is oriented perpendicular to the buff axis of SLM 702 and the buff axis of SLM 702 is advantageously oriented parallel to horizontally linearly polarized light directed into the system. Other orientations of the buff axes are also effective provided that the SLM and compensator cell buff axes remain perpendicular to one another.
[0074] As described above for the previous embodiments, the off axis configuration shown in FIGS. 7 a and 7 b provide identical results for Cases 1 and 3 and Cases 2 and 4 . This configuration also provides good results over a broad spectrum similar to the results illustrated in FIGS. 5 b and 5 c . Therefore, system 700 is also able to provide a continuously viewable system which more effectively utilizes light from the light source when compared to the conventional reflective systems illustrated in FIGS. 1 b - c and FIG. 3 a.
[0075] Although only certain specific embodiments of the present invention have been described in detail, it should be understood that the present invention may be embodied in many other specific forms without departing from the spirit or scope of the invention. For example, although the systems have been described above as using horizontally linearly polarized light as the initial input light polarization, this is not a requirement. Instead, it should be understood that the initial input light polarization may alternatively be vertically linearly polarized light. Therefore, the present examples are to be considered as illustrative and not restrictive, and the invention is not to be limited to the details given herein, but may be modified within the scope of the appended claims.
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A reflection mode, ferroelectric liquid crystal spatial light modulating system, includes a light reflecting type spatial light modulator. The spatial light modulator has a light reflecting surface cooperating with a layer of ferroelectric liquid crystal light modulating medium switchable between first and second states so as to act on light in different first and second ways, respectively. A switching arrangement switches the liquid crystal light modulating medium between the first and second states and an illumination arrangement produces a source of light. An optics arrangement is optically coupled the spatial light modulator and the illumination arrangement such that light is directed from the source of light into the spatial light modulator for reflection back out of the modulator and such that reflected light is directed from the spatial light modulator into a predetermined viewing area. The optics arrangement includes a passive quarter wave plate positioned in the optical path between the light source and the spatial light modulator and in the optical path between the spatial light modulator and the viewing area. A compensator cell is also positioned in the optical path between the light source and the spatial light modulator and in the optical path between the spatial light modulator and the viewing area. The compensator cell has a layer of ferroelectric liquid crystal light modulating medium switchable between a primary and a secondary state so as to act on light in different primary and secondary ways, respectively.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a sewing machine and more particularly relates to a sewing machine having an indicating device which is electrically operated to indicate a plurality of selected patterns arranged to be stitched in combination.
[0003] 2. Related Art
[0004] Now a sewing machine having a zigzag stitching function for forming the patterns of zigzag stitches is available in the market and is widely used. Such a sewing machine is generally provided with an indicating device for indicating the patterns selected by the user for confirmation at the time of stitching the selected patterns.
[0005] The pattern data for stitching patterns are generally formed up in consideration of the difference in efficiency of circular arc movement of machine needle and of forward and reverse movement of work feeding mechanism. It is, therefore, unavoidable that the pattern data indicated as these are in the indicating device will be different from the actually stitched result of the patterns. Therefore, the indication data for indicating patterns are generally prepared by using the bit map data for each of the patterns to be selectively stitched.
SUMMARY OF THE INVENTION
[0006] However, in the recent years, the sewing machine has come to have many functions including optional combination of patterns, optional enlargement and reduction of patterns and so on. In fact, the conventional indicating function is not sufficient for satisfying such variation of patterns to be stitched.
[0007] For example, in case the patterns are to be stitched in combination, the patterns are not indicated in a combined state, but are indicated individually. Further, in case the patterns are optionally enlarged or reduced by the user, the patterns indicated will remain as unchanged.
[0008] The invention has been provided to eliminate such defects and disadvantages of the prior art.
[0009] For attaining the object, the invention has been made in connection with a sewing machine for stitching optionally selected patterns in accordance with pattern data, and the sewing machine comprises a means for giving indication data for said pattern data, a means for arranging said indication data in accordance with a combination of said pattern data, a means for changing said indication data in accordance with the change of said pattern data, a means for indicating said indication data in a manner that said indication data may be scrolled, a means for designating an initial one of the pattern data indicated at said indicating means.
[0010] With the combination of elements, in case the patterns are optionally combined, the indication data is indicated in accordance with the combined patterns and may be changed in accordance with change of the pattern data. Such indication data as indicated will be confirmed by the machine user as being the same with the stitched result of patterns which are selected to be stitched. Further, since the means for indicating the indication data may be so formed as to scroll the indicated patterns, all of the patterns may be indicated even if a series patterns to be indicated are beyond the indication area of the indicating device. Further, with a means provided to designate the pattern data to be changed at the indication surface of the indicating means, the machine user may change the pattern data while the user is watching the indication data.
[0011] Further, according to the invention, in case the same patterns are combined linearly, the same patterns may be indicated in series while the image treatment is performed, wherein the stitch end point of indication data for the pattern data preceding the next indication data for the next pattern data is made to be a stitch start point of the next indication data for the next pattern data. Therefore, the actually indicated patterns may be substantially the same with the patterns to be actually stitched.
[0012] Further, according to the invention, in case the pattern data preceding the initial pattern data for the patterns indicated at the indicating means is the same with the initial pattern data, it is discriminated whether or not the initial pattern data overlaps the preceding pattern data. In case it is discriminated that the initial pattern data overlaps the preceding pattern data, the image treatment is started from the preceding pattern data so that the overlapped portion of pattern data may be indicated at the indicating means.
BRIEF DESCRIPTION OF THE DRAWINGS
[0013] [0013]FIG. 1 is a block diagram showing the embodiment of the invention.
[0014] [0014]FIG. 2 is an explanatory view showing the operation of the embodiment of the invention.
[0015] [0015]FIG. 3 is another explanatory view showing the operation of the embodiment of the invention.
[0016] [0016]FIG. 4(A) is an explanatory view showing the operation of the embodiment of the invention in connection with FIG. 3.
[0017] [0017]FIG. 4(B) is an explanatory view showing the operation of the embodiment of the invention in connection with FIG. 4(A).
[0018] [0018]FIG. 5 is a flow chart showing the operation of the embodiment of the invention.
[0019] [0019]FIG. 6 is a flow chart showing the operation of the embodiment of the invention in connection with FIG. 5.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0020] The invention will be described in reference to the attached drawings.
[0021] In FIG. 1, a CPU 1 including a microcomputer is provided to control the essential parts of a sewing machine. A pattern data memory 2 has the stitch data of predetermined zigzag patterns stored therein and is connected to the CPU 1 . An indication data memory 5 has the indication data stored therein as corresponding to the patterns stored in the pattern data memory 2 and is connected to the CPU 1 .
[0022] A pattern selecting/combining device 3 is provided so as to be operated by a machine user to select one or a plurality of patterns in combination from the patterns stored in the pattern data memory 2 . A pattern modifying device 4 provided so as to be operated by a machine user to modify, for example, to reduce, enlarge or reverse the selected pattern or patterns.
[0023] A pattern indicating device 8 is provided to indicate thereat the pattern or patterns selected by the pattern selecting/combining device 3 so that the indicated pattern or patterns may be confirmed by the machine user.
[0024] An indication data combining device 6 is provided to form up a list therein of the patterns which are selected in combination. An image treating device 7 is provided to treat the image of combined patterns in accordance with the pattern list so that the treated image of patterns may be indicated at the pattern indicating device 8 .
[0025] In case the selected pattern or patterns are to be modified, a pattern modifying signal is transmitted to the image treating device 7 so that the modified image of a pattern or patterns in combination may be indicated at the pattern indicating device 8 .
[0026] A cursor device 9 is provided which is operated with operation of a button or the like by the machine user to indicate a cursor at the indicating device 8 so that the cursor may be used to point to an optional one of the patterns indicated at the pattern indicating device 8 . The cursor may be pointed to a pattern which is to be indicated at an initial position or which is to be modified.
[0027] The pattern data selected, combined and modified by the pattern selecting/combining device 3 is recorded in a pattern data recording memory 50 . A stitching mechanism 51 is operated to perform a stitching operation in accordance with the pattern data recorded in the pattern data recording memory 50 .
[0028] As is described hereinbefore, the indication data combining device 6 will operate to form up a list of indication data in reference to the indication data stored in the indication data memory 5 in accordance with the patterns combined by the pattern selecting/combining device 3 , and the image treating device 7 will produce the indication data on the basis of the indication data list so that the indication data corresponding to the combined patterns to be stitched may be indicated at the indicating device 8 .
[0029] Further, in response to a pattern modifying signal, the image treating device 7 will produce new indication data on the basis of the indication data stored in the indication data memory 5 so that a modified pattern may be indicated at the indicating device 8 .
[0030] According to the embodiment, the combined patterns are indicated as arranged linearly from left to right as shown in FIGS. 2 through 4. The image treating device 7 will treat the image of patterns so as to be continuous to one another in case the patterns are of an identical type.
[0031] [0031]FIG. 2 shows that a pattern 60 and a pattern 61 are in a combined state. In this case, the stitch end point E 0 of the pattern 60 is may be indicated as the stitch start point S 1 of the pattern 61 .
[0032] However as shown in FIG. 3, in case a pattern 62 is repeatedly stitched in series wherein the stitch end point E 2 is not at the end of the pattern and terminates at a stitch start point S 2 , it becomes necessary to make a special treatment of pattern image. More precisely, as shown in FIG. 4, in case the second pattern 63 of the same patterns is indicated in the first position at the pattern indicating device 8 , it becomes necessary to indicate a portion D of the pattern 62 which overlaps the stitch start point S 3 of the pattern 63 .
[0033] The indication may be realized by a special treatment of pattern image as follows:
[0034] In FIG. 5, when the first pattern is selected, the initial data is decided from the position data of cursor so that a cursor 90 may come to an optional position in the indicating device 8 while the currently indicated data is disappeared, and then the pattern image position is initialized (Steps S 1 , S 2 , S 3 ). Subsequently the indication data for the initial pattern is read out (step S 4 ). Subsequently it is discriminated whether or not the read out indication data is identical with the preceding indication data (step S 5 ). In case the read out indication data is identical with the preceding indication data, the image treatment jumps to the subroutine (FIG. 6) (step S 6 ). In case the read out indication data is not identical with the preceding indication data, the pattern which is at the cursor position is turned to blue and a cursor line is drawn (steps S 7 , S 8 , S 9 ) while the other patterns are treated to turn to red (step S 10 ), and then the indication of pattern is started from the pattern image start position (step S 11 ). Subsequently, the width between the pattern indication start point and the pattern indication end point of the pattern indication start data is added to the pattern image position to make the next indication start point (step S 12 ). Subsequently it is checked whether or not the next data exists in the list (step S 12 ). In case the next data exists, the indication of the next indication data is carried out (step S 14 ). In this case, it is checked whether or not the indicating area of the pattern indicating device 8 remains to be further available (step S 15 ). In case there is no indicating area remaining available, the image treatment is finished. In case the indicating area remains, the image treatment returns to step S 7 and the same operation is repeated.
[0035] The pattern image treatment at the step S 6 will be described in reference to FIGS. 4 and 6.
[0036] The indication data for the initial pattern 63 is read out (step S 20 ) and the pattern image start position is initialized (step S 21 ). Then as shown in FIG. 4, it is discriminated whether or not there is the portion D overlapping the preceding pattern (steps S 22 , S 23 ). In case there is no overlapping portion, the image treatment comes to end. In case there is an overlapping portion, it is discriminated whether or not the preceding pattern 62 is identical with the currently indicated pattern 63 (step S 24 ). In case the preceding pattern is not identical with the currently indicated pattern, the image treatment comes to end. In case the preceding pattern is identical with the currently indicated pattern, the indication data for the preceding pattern 62 is set as a pattern image start data (step S 25 ) and the pattern image start position is displaced to the pattern image start point S 2 of the preceding pattern 62 by the data width (step S 26 ). In case the pattern image start data is the initial data of the pattern list, the image treatment comes to end (step S 27 ). In case the width of the pattern image start position fails to exceed the overlap width D, it becomes necessary to further displace the pattern image start position. In this case, the image treatment is returned to the step start point S 24 (step S 28 ).
[0037] As is described above, provided that at the step S 26 , image treatment is started from the pattern 62 while the pattern 63 is indicated as the initial pattern at the pattern indicating device 8 , the overlap portion D at the end part of the preceding pattern 62 may be properly indicated at the pattern indicating device 8 as shown in FIG. 4.
[0038] In case a plurality of optionally selected patterns are stitched in combination, the indication data for the patterns may be indicated at the indicating device and may be changed in accordance with the change of the selected patterns. Thus the machine user may confirm the patterns to be stitched before starting the stitching operation of the patterns.
[0039] 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 are intended to be included within the scope of the following claims.
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Disclosed is a sewing machine having an indicating device for indicating selected patterns in a manner that the same may be substantially the same with the actually stitched result of the selected patterns, wherein the patterns selected by a user by operation of a pattern selecting/combining device 3 are indicated at an indicating device 8 and wherein in response to an optional combination or modification of the selected patterns, an image treating device 7 accordingly treats the image of the indicated patterns to indicate the same at the indicating device 8. The pattern data are stored in a pattern data memory 50 and a stitching mechanism 51 is operated in accordance with the pattern data stored in the pattern data memory 50, thereby to form the patterns of stitches.
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BACKGROUND OF THE INVENTION
[0001] Optical emitter-detector pairs (photo-eye) are used for sensing obstructions on motorized door operators. The emitter half creates a beam of light that is pointed across the door opening. This beam is received by the optical detector along with all the other sources of ambient light in the room. Ambient light is cancelled out largely by switching the emitter at a frequency much higher than ambient sources, say 30-khz, and using a frequency filter in the detector.
[0002] Such emitter-receivers are well known and available complete with all associated frequency driver and frequency discrimination circuitry. They are commonly used in garage door operators for obstruction detection and as remote controls on televisions.
[0003] In the instant application if an obstacle is in the door opening it is expected that it will block the light beam received by the detector thereby ultimately closing a switch contact. With the contact closed the motor operator will either not-close if it is already open or stop closing and re-open.
[0004] One mechanical mounting option has the emitter mounted on the floor to one side of a door or gate opening, and the detector mounted on the floor on the opposite side of the opening. The photo-eye is thereby fixed or non-moving but protects the opening. Wires connect emitter to detector to motor operator and run around the opening to avoid the moving door or gate. Typically 100-feet of wire is required for connection of the system.
[0005] Another mechanical option has the emitter and detector fastened on opposite sides of the moving edge of the door or gate, traveling with it. Flexible wire, coil cord, or a rotary wire reel connects the moving photo-eye to a fixed motor operator. The most common form being the 2-conductor wire reel. In the spring loaded wire reel electrical contact is made from its rotating reel to its stationary body by means of conductive brushes and rings. Such brushes create electrical noise while rotating when they are new, and as they age or if they become dirty the noise takes the form of momentary electrical disconnection from the brush to the ring.
[0006] All photo-eye systems require power to operate and in return provide a signal in the form of a voltage, voltage pulses, or a contact closure. Therefore you might conclude that two wires would be required for supplying power and one or two more wires would be used for the signal. In actual practice two-conductor, unshielded, non-twisted wire is preferred by installers primarily because they only have two-conductor wire and two-conductor wire reels are more common than others. Whereupon the manufacturers of photo-eyes designed their units such that power and signal can be sent over the same two wires.
[0007] Photo-eye alignment signals are superimposed or modulated into its two power wires. The motor operator will not work if the signal from the photo-eye is missing and will end up in the fully open position, unable to close. This becomes a security issue in that the door or gate cannot close unless the safety system is bypassed. Troubleshooting such a system problem without the benefit of an oscilloscope is difficult because the alignment signal is mixed with the power. Some industrial high security operators use 4-wire photo-eyes to avoid the troubleshooting difficulties involved with two wire systems.
[0008] Residential garage door operators use a microprocessor to receive the pulses from the photo-eye and software to detect their loss. If such pulses are missing the motor operator will not close if it is already open or stop and re-open if it is closing. Therefore if the photo-eye system has a broken wire, a shorted wire, a defective component, is misaligned, has no power or if the beam is blocked the effect is the same, the door will not close. Troubleshooting is difficult, and failures common, such that a bypass has been devised. Holding down the pushbutton for more than 2-seconds will close the door even if the photo-eye beam is blocked. The button must be held down continuously until the door is fully closed or it will stop.
[0009] Industrial door and gate operators do not come with a photo-eye. Conditions of dirt or mud, process dust or muck, snow or ice may make an optical system impractical because their lenses need continuous cleaning. To this end industrial motorized operators come with just an electrical terminal for the attachment of any number of different safety systems. A simple contact closure at this terminal will stop the motor operator from closing if it is open and will reopen it if closing. This invention primarily addresses this type of motor operator when conditions favor to the use of a photo-eye safety system.
[0010] The industrial operators predominantly tend to use electromechanical relay logic instead of microprocessor or electronic logic. The reason is reliability related to environmental issues, and electrical noise. Environmentally an industrial motor operator will be hot, wet and dirty. Each time the industrial motor stops every electrical conductor and trace inside the electrical enclosure will be at ground zero to a huge radiated and conducted electromagnetic pulse. This is caused by the residual magnetic field energy left in the motors windings collapsing whenever the motor contactor opens. The motor is located outside of the electrical enclosure but its high voltage arc is formed across contacts located inside the enclosure as they open the motors magnetic field.
[0011] Industrial doors and gates are heavy. They are built with thick steel to stop a vehicle from pushing through them and a typical example might be 3,000-lbs and an unusual example might be 30,000-lbs, moving this heavy load by hand is kind of, tough. They protect areas that absolutely require security. It is therefore more important that these motor operators work than say your garage door at home. If a photo-eye system is used it must be able to be repaired easily and bypassed temporarily when necessary.
DESCRIPTION OF PRIOR ART
[0012] [0012]FIG. 2 describes a generic and commonly used optical emitter detector pairs available from numerous suppliers. The emitter ( 2 ) creates a beam of modulated light ( 3 ), and the detector ( 1 ) decodes the modulated light.
[0013] A light emitting diode and frequency driving circuitry is all packaged into one device ( 34 ). It gets its power from capacitor ( 36 ) through diode ( 35 ) the reasons for this will become apparent. Power is applied to ( 39 ) and ( 40 ).
[0014] A light detecting device, amplifier, and frequency discriminating components are all packaged into one device ( 33 ). Once it detects the correct modulation frequency it begins to pulse the base of a transistor ( 30 ). This acts like a switch briefly shorting out the input power terminals ( 37 ) ( 38 ). Diode ( 31 ) charges capacitor ( 32 ) and allows ( 38 ) to be shorted to ( 37 ) briefly while maintaining a charge on the capacitor ( 38 ). The light detector ( 33 ) gets its power from capacitor ( 32 ) thereby it does not loose power during the brief outages described.
[0015] These optical emitter-detector pairs are connected to each other as depicted in FIG. 1, the emitter ( 2 ) sends a modulated light beam ( 3 ), to the detector ( 1 ). They are connected in parallel using 2-conductors to this invention on pins ( 4 ) and ( 5 ). These 2-wires carry both the power to run the optical emitter-detector and an electrical signal indicative that the desired light beam is present or absent.
[0016] This dual electrical signal is depicted in FIG. 3. The voltage on ( 4 ) is plotted on the y-axis with ( 5 ) as the ground-reference, and time is the x-axis. The first 4-milliseconds depict no light beam and thereby no shorting pulses and from 4-milliseconds on depicts the presence of light with shorting pulses.
[0017] It should be understood that such 2-conductor optical emitter-detectors and their operation as described are not part of this invention, that they represent prior art. Manufacturers of the photo-eye systems generally recommend a voltage regulated power supply be provided and that a dropping resistor be used to power the units and allow the electrical shorting pulses to occur. The shorting pulses are then coupled into a microprocessor or some other means left to the user's imagination.
BRIEF SUMMARY OF THE INVENTION
[0018] A voltage controlled current source (VCCS) supplies constant current, variable voltage, to power the photo-eye. Constant current removes susceptibility to electromagnetic noise seeking to demodulate onto the signal wire and removes ground loop signals present in the metal door components.
[0019] An electrostatic filter removes static discharges conducted through direct contact and all polarized direct contact noise signals. One of the 2-terminals can be referenced to ground leaving only a single signal/power wire. Since the door, gate, frame, or track is commonly made of metal they can act as the ground conductor eliminating one of the wires.
[0020] This invention uses two indicator lamps for diagnostics; they indicate four conditions; a) Ready, b) Not Connected, c) Blocked Beam, d) No power. This allows single or two conductor systems to have the same troubleshooting information as the 4-wire systems. The detail of the diagnostics are as follows;
[0021] If just the green lamp illuminates, the system is good. Indicating the optical emitter and detector are connected, working properly, power is present, and the beam is aligned. The motor operator is able to close the door or gate.
[0022] If just the red lamp illuminates, the system is broken. The optical emitter detector is not connected or its wire is not making connection. Power is applied but one or both optical components are not working or not connected. The motor operator will not close the gate or door.
[0023] If both the red and the green lamps illuminate, the beam is merely blocked or misaligned. This also means the wire is connected, power is applied, and the emitter detectors are working properly. The motor operator will not close the gate or door.
[0024] If neither lamp illuminates there is no power coming from the operator.
[0025] The preferred embodiment accomplishes all of this without using any integrated circuits, software or microprocessors. The lack of integrated circuits allows proper functioning with any unregulated voltage from 5 to 50 volts. It allows operation under water and being covered with dirt or mud and does not require coatings or environmental sealing or enclosures.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] [0026]FIG. 1 is a schematic diagram of the preferred embodiment.
[0027] [0027]FIG. 2 is reference drawing of a typical 2-wire optical emitter-detector.
[0028] [0028]FIG. 3 depicts the electrical signals superimposed on the power for either a completed light beam or broken light beam.
[0029] [0029]FIG. 4 is a block diagram of the invention.
DETAILED DESCRIPTION OF THE INVENTION
[0030] [0030]FIG. 4 is a block diagram of the invention. Electrical power (DC) is applied to ( 25 ) and referenced to common ( 24 ). A voltage controlled current source ( 43 ) (VCCS) supplies constant current from ( 25 ) to ( 4 ). This current is typically fixed at some value, say 22-ma, and will allow the voltage on ( 4 ) to vary. As the voltage on ( 4 ) varies from common ( 24 ) to the supply voltage ( 25 ) the current remains fixed at the preset value. The VCCS ( 43 ) powering the photo-eye will successfully operate photo-eyes of any voltage, and allow either intermittent or indefinite short circuits while drawing the same constant current.
[0031] Constant current is naturally noise immune. Radiated electromagnetic interference (EMI) takes the form of a rapidly changing voltage, measured in volts per meter. Since 20-volts per meter will cook a human, radiated EMI is commonly less than this. It is the changing voltage of EMI that induces a current in fixed conductors located in its field, similar to the same effect noted in a transformer. If a current is induced into the 100-feet or so of photo-eye wire, it will create a voltage limited only by the wires impedance to ground. The current will be generating a voltage in the wire to stop the decay of the magnetic field created by the current in the wire.
[0032] The effect of current induced EMI into a constant current variable voltage source is the ratio between the currents. If 2-ma of EMI is induced into a wire driven by a 20-ma current source, 0.1-volt of EMI is produced (2-ma/20-ma). If the same 2-ma of EMI is induced into a wire with a pull up resistor, such as in prior art, ohms law has the voltage equal to the resistance times the current. A 1,000 ohm resistor with 2-ma of EMI produces 2-volts of noise signal (2-ma×1,000-ohms). Enough noise to mess up 5-volt logic.
[0033] This is why current sources are inherently less susceptible to noise than resistance sources; the induced noise current is multiplied by the resistance of the resistance source but divided by the current of the current source. Prior art uses a resistor as a source from a regulated voltage supply and then must reduce EMI by inserting a capacitor across the photo-eye wires. The capacitor must be large to reduce EMI significantly but the photo-eyes fast shorting signal is also reduced and a strain is placed on the shorting transistor ( 30 ).
[0034] In FIG. 4, Terminal ( 5 ) could optionally be connected to ground leaving only 1-signal/power wire ( 4 ). With ( 5 ) connected to ground its impedance to ground is as close to zero as you can get preventing it from demodulating any electrical noise. If the metal frame of the door or gate is used this is one line you know cannot be broken.
[0035] The photo-eye system ( 1 ) ( 2 ) will produce shorting pulses as shown in FIG. 3 to terminal ( 4 ) that is connected to a missing short detector ( 44 ). After a predetermined number of shorting pulses are missing the switch ( 17 ) will close. This causes the terminal ( 23 ) to be connected to ( 24 ) signaling a motorized operator that there is an obstruction. If a jumper wire were to be connected from ( 4 ) to ( 5 ), this would make a continuous short and the missing short detector ( 44 ) would not close switch ( 17 ). Thus providing a method of bypassing the system but one that requires determined effort because a critical safety feature has been disabled.
[0036] The switch ( 17 ) closure also illuminates the red lamp ( 16 ) indicating the lack of shorting pulses or signal from the photo-eye. The red lamp ( 16 ) derives its power from terminal ( 22 ) that can be connected to any convenient voltage used by the motor operator or it could be connected to terminal ( 25 ) if such voltage is the same as that used by the motor operator.
[0037] A current measuring means ( 42 ) detects if the full current from the VCCS ( 43 ) is present. If the VCCS ( 43 ) has full current then the green lamp ( 10 ) illuminates. Anything less than full current will not illuminate the green lamp ( 10 ). Most photo-eye emitters use a light emitting diode as the source for the light. Such devices light output is dependant entirely on current, normally a maximum of 20-ma. The photo-eye detector only receives the light and uses less energy, normally 1-ma if no signal is present and 3-ma with a signal present. The current drawn by the photo-eye system should then be 21-ma if both are connected. If the emitter ( 2 ) or the detector ( 1 ) were not both connected then the current sensor ( 42 ) would be adjusted such that the green lamp ( 10 ) would not illuminate.
[0038] The circuitry of FIG. 1 is a detailed schematic of the preferred embodiment. Terminal ( 24 ) connects to a grounded or common point inside a motor operator; terminal ( 5 ) connects to a grounded or common point convenient to the photo-eye ( 1 ) ( 2 ). Terminal ( 21 ) is connected to a source of power such as a 24-volt AC transformer but it can be any voltage from 5-volts through 50-volts. The voltage is rectified by diode ( 18 ) and filtered by capacitor ( 19 ) to form the unregulated supply voltage ( 25 ). Items ( 18 ) and ( 19 ) are not required if the motor operator has a source of DC power, in this eventuality ( 21 ) and ( 25 ) are simply connected together.
[0039] Terminal ( 4 ) is the 1-wire signal and power pin and it is protected from static electricity by diodes ( 6 & 7 ). If a high voltage arc were to jump to terminal ( 4 ) then diode ( 6 ) would conduct if it tried to exceed the supply voltage ( 25 ) and diode ( 7 ) would conduct if it tried to go below the common point ( 5 ). Normal shorting signals from the photo-eye connected to terminal ( 4 ), that falls between the rails of common ( 5 ) and the supply ( 25 ) would not be burdened by the static protection network as it remains an open circuit.
[0040] The voltage controlled current source ( 43 ) is formed using 4-components ( 8 , 9 , 10 , & 11 ). The light emitting diode ( 10 ) is driven by resistor ( 11 ) to a voltage below the supply rail ( 25 ), say 1.8-volt. This voltage dropped across the LED ( 10 ) is constant and independent of the supply voltage. This constant voltage from the LED ( 10 ) connects to the base of PNP transistor ( 9 ). The emitter of PNP transistor ( 9 ) will thereby be 0.7-volts higher or 1.1-volts below the supply rail ( 25 ). The current in the emitter will be determined by the value of resistor ( 8 ). With 1.1 volts across it, using ohms law, resistor ( 8 ) with a value of 51-ohms will produce 22-ma in the emitter. Resistor ( 8 ) value sets the amount of constant current supplied. The current in the collector of the transistor ( 9 ) will be close to the same current as its emitter and thus forms a current source.
[0041] It can be seen that if the collector of ( 9 ) is shorted to ground ( 5 ) or even below ground that the current it provides will not vary. If the supply voltage ( 25 ) has ripple or big voltage variations the current will remain constant on terminal ( 4 ). As either the supply voltage varies or the load voltage varies the current will remain the same. This will remain true as long as the connected load, the photo-eye, can draw the current being thus supplied. If the photo-eye, its emitter or its detector were to be disconnected the current could not be maintained.
[0042] The same 4-components ( 8 , 9 , 10 , & 11 ) form the load sensor ( 42 ). This is set by the ratio between resistor ( 8 ) and resistor ( 11 ). As stated earlier, the value of resistor ( 8 ) sets the constant current coming from the collector of the transistor ( 9 ) then the value of resistor ( 11 ) can be varied to set the percentage of current at which the LED ( 10 ) turns on. The reasoning behind this is as follows;
[0043] It can be seen that if terminal ( 4 ) is not connected to anything, the collector of transistor ( 9 ) is open and no current is being used by the collector-emitter junction. The transistor ( 9 ) has become just a diode with a roughly constant 0.7-volt drop from base to emitter. Since the LED ( 10 ) requires 1.8-volt to be lit an additional 1.1-volts is required to be dropped across resistor ( 8 ) before it can be lit. Until the LED ( 10 ) is lit it is basically an open circuit and does not voltage regulate. The voltage across resistor ( 8 ) is then entirely dependant on the current drawn from resistor ( 11 ).
[0044] If resistor ( 11 ) is a high resistance, say 10,000-ohms, and resistor ( 8 ), is 51-ohms as stated earlier, and with a 34-volt supply voltage ( 25 ), ohms law has 3.3-ma being drawn through resistor ( 8 ) and dropping 0.17-volts across it. This voltage plus the 0.7-volts from the emitter-base junction of ( 9 ) is not enough to turn on the LED ( 10 ) but it has reduced the current required to turn it on.
[0045] In another example if resistor ( 11 ) is 3,400-ohms, and the supply voltage is 34-volts then 10-ma will be drawn though resistors ( 11 & 8 ) and the base-emitter ( 9 ) junction. This 10-ma will cause 0.51-volts to be dropped across resistor ( 8 ) and 0.7-volts dropped across transistor ( 9 ) for a total of 1.21-volts; not enough to turn on the LED but the current required to turn it on has been reduced further. In this manner resistor ( 11 ) may be chosen to pick the percentage of current required to turn on the green LED ( 10 ).
[0046] The missing short detector function ( 44 ) is performed by 4-components, ( 12 , 13 , 14 , & 15 ). When the photo-eye detector ( 1 ) is receiving a valid light beam ( 3 ) it is periodically shorting itself out with a switch ( 30 ). This conducts through diode ( 12 ) to discharge capacitor ( 14 ) to ground. Once the beam ( 3 ) is blocked the shorting pulses stop and capacitor ( 14 ) begins to charge through resistor ( 13 ). After some time, say 0.1-sec, 33-shorting pulses have not occurred and the capacitor ( 14 ) conducts its voltage to Zener diode ( 15 ) and the base of the NPN transistor ( 17 ), eventually turning them both on.
[0047] The transistor ( 17 ) acts as a switch from terminal ( 23 ) to ( 24 ). These terminals connect to a motor operator and signal that it should not close. In addition the red LED ( 16 ) is lit through resistor ( 20 ) and power supplied by terminal ( 22 ). Terminal ( 22 ) can be connected to any DC voltage lower than, equal to, or greater than power supply ( 25 ) within the transistors rating. For example if the motor operator ran from a 12-volt supply, terminal ( 22 ) could connect to it. This would insure that the higher voltages of the power supply ( 25 ) through terminal ( 23 ) would not affect the motor operator's lower voltage logic.
[0048] The action of the three diodes ( 6 , 7 , & 12 ) and capacitor ( 14 ) combine to eliminate electrical noise. It can be seen that if terminal ( 4 ) lost connection briefly with the photo-eye system that diode ( 12 ) would prevent this eventuality from speeding up the charge rate of the capacitor ( 14 ). Such a situation occurs when the brush inside a wire reel fails to make good contact while rotating over dirt. With the loss of connection, terminal ( 4 ) is forced to the supply ( 25 ) rail by the current source. Also if a brief positive going surge, spike or voltage were to be connected to terminal ( 4 ) the effect would be the same.
[0049] If a negative going surge, spike or voltage were to be connected to terminal ( 4 ) this would be clamped by diode ( 7 ) at 0.7-volts below ground, and raised 0.7-volts by diode ( 12 ) equally, preventing capacitor ( 14 ) from being reversed and damaged. Since ground shorts do nothing but reset the timing and capacitor ( 14 ) this negative going noise does not affect its operation.
[0050] An improved method for a photo-eye interface has been disclosed herein. While illustrative embodiments of the invention have been described, it is understood that various modifications to the disclosed will be apparent to those skilled in the art. It is intended that this invention be limited only by its claims.
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A one wire interface for optical emitter-detectors is disclosed that is fail-safe, simple, and includes diagnostics, noise and static protection. Two indicator lamps are used for diagnostics indicating four conditions; a) Ready, b) Not Connected, c) Blocked Beam, d) No power. This allows single or two conductor systems to have the same troubleshooting information as the 4-wire systems.
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RELATED APPLICATIONS
This application is a continuation-in-part of U.S. patent application Ser. No. 13/751,007, filed on Jan. 25, 2013, entitled “Reconfigurable Snowboard/Downhill Skis” which claims the benefit of the filing date of U.S. provisional patent application Ser. No. 61/591,818, filed Jan. 27, 2012, entitled “Alpine Split Board” and U.S. provisional patent application Ser. No. 61/681,069, filed Aug. 8, 2012, entitled “Alpine Split Board,” both of which are incorporated by reference herein in their entireties.
BACKGROUND
1. Technical Field
The present disclosure relates to snow-sport equipment and more specifically to a combination snowboard and downhill ski.
2. Introduction
A wide variety of riding products exist for mountain snow sport enthusiasts. Downhill skiing has a long history of innovation and a great variety of ski designs have been developed over the years. Generally downhill skis are substantially flat axial planks with a binding used to couple with a ski boot. Each axial side of the individual skis has a sharpened metal edge that gives the skier the ability to turn and control his speed during downhill descent. Oftentimes the axial side of the individual skis have a parabolic sidecut, meaning the tip and tail of the ski are wider then the middle of the axial distance. The parabolic shape gives the skier more control over turning because the sidecut naturally encourages parabolic motion downhill as a skier applies pressure to the given edge.
Like downhill ski technology, there are many solutions for cross-country skiing and backcountry/alpine trekking One common design feature for cross-country skiing and backcountry/alpine trekking skis include a binding that holds the toe of the boot securely in place while allowing the heel of the boot to rise and fall in a rhythmic motion. The rhythmic motion facilitates gliding as opposed to a marching motion that is used when snowshoeing.
More recently, snowboarding has enjoyed huge popularity and snowboard design has progressed steadily. Like downhill skis, snowboards are typically designed with substantially parabolic edges to facilitate turning. For functional and safety reasons, snowboards also typically employ bindings that semi-permanently hold the snowboarders boot to the board, forcing the rider to strap in and strap out of the bindings one or two feet when a rider wants to traverse flat or upward portions of the mountain or trail. Likewise, unstrapping one foot from a snowboard and “skating” eliminates the advantage of having a large surface area under a rider's feet, causing the rider's feet to sink into the snow and requiring more effort.
In addition to skis and snowboards for use in specific skiing/riding styles, splitboards, which allow use of a single device for more than one ski/ride style, have gained a somewhat recent popularity. A splitboard is a reconfigurable snowboard/alpine-trekking ski combination designed with various clasps and multi-purpose binding configurations to allow a user to physically split a snowboard down its length into two skis, reconfigure the bindings, and use the skis for cross country skiing or backcountry trekking However, splitboards do not have inside edges suitable for downhill skiing. Due to the lack of edges and a function-limiting straight inside edge, splitboard skis are unusable for downhill skiing.
SUMMARY
Additional features and advantages of the disclosure will be set forth in the description which follows, and in part will be obvious from the description, or can be learned by practice of the herein disclosed principles. The features and advantages of the disclosure can be realized and obtained by means of the instruments and combinations particularly pointed out in the appended claims. These and other features of the disclosure will become more fully apparent from the following description and appended claims, or can be learned by the practice of the principles set forth herein.
Disclosed are various embodiments of a combination ski-snowboard device interchangeably configured in one of: a ski configuration comprising two skis each with both an inside and outside edge and a ski binding mounting systems, and in a snowboard configuration having two outside edges and two binding mounting systems.
Some embodiments involve a ski-snowboard combination device involving a first gliding board having and first edge having a substantially concave shape, a second gliding board having a first edge having a substantially concave shape, and a fastening device configured to reversibly affix the inside edge of the first gliding board to the inside edge of the second gliding board, thereby forming an opening with two convex sides.
In some embodiments, the ski-snowboard combination device comprises a ski binding mounting system coupled with each of the gliding boards and one half of a snowboard binding system, thereby allowing the ski-snowboard to be converted between ski and snowboard configurations.
In some embodiments, the ski binding mounting systems involve a bottom plate coupled with a gliding board, an aperture in the bottom plate, and a top plate having a disk disposed on the bottom-side surface of the top plate. The disk releasably couples with the aperture of the bottom plate and releases in the event of a threshold level of torque applied to the disk and a topside surface of the top plate is configured with a boot. In some embodiments, the bottom plate includes a torque-sensitive release mechanism, a set screw accessible from the outside of the bottom plate in mechanical communication with the torque-sensitive release mechanism and configured for adjusting the threshold torque, an release setting gauge visible from the outside of the bottom plate for displaying a quantified representation of the threshold torque.
BRIEF DESCRIPTION OF THE DRAWINGS
In order to describe the manner in which the above-recited and other advantages and features of the disclosure can be obtained, a more particular description of the principles briefly described above will be rendered by reference to specific embodiments thereof which are illustrated in the appended drawings. Understanding that these drawings depict only exemplary embodiments of the disclosure and are not therefore to be considered to be limiting of its scope, the principles herein are described and explained with additional specificity and detail through the use of the accompanying drawings in which:
FIG. 1A illustrates isometric top and side views of a combination snowboard/skis in a snowboard configuration according to some embodiments of the present technology;
FIG. 1B illustrates isometric top and side views of the combination snowboard/skis from FIG. 1A in a ski configuration according to some embodiments of the present technology;
FIG. 2 illustrates various isometric views of an exemplary binding for coupling with a combination snowboard/skis according to some embodiments of the present technology; FIG. 3A illustrates isometric top and side views of a combination snowboard/skis in a ski configuration according to some embodiments of the present technology;
FIG. 3B illustrates isometric top and side views of the combination snowboard/skis from FIG. 3A in a snowboard configuration according to some embodiments of the present technology;
FIG. 4A illustrates a method of converting combination snowboard/skis from a snowboard configuration to a ski configuration according to some embodiments of the present technology;
FIG. 4B illustrates a method of converting combination snowboard/skis from a ski configuration to a snowboarding configuration according to some embodiments of the present technology;
FIG. 5 illustrates two isometric views of a plate binding system according to some embodiments of the present technology; and
FIG. 6 illustrates an exploded view of a bottom plate of a plate binding system according to some embodiments of the present technology;
FIG. 7 illustrates a side view of an exemplary binding for coupling with a combination snowboard/skis in a ski configuration and a snowboarding configuration, as well as a conventional alpine ski, and conventional snowboard according to some embodiments of the present technology;
FIG. 8 illustrates a perspective view of an exemplary binding for coupling with a combination snowboard/skis in a ski configuration and a snowboarding configuration, as well as a conventional alpine ski, and conventional snowboard according to some embodiments of the present technology;
FIG. 9 illustrates rear view of an exemplary binding for coupling with a combination snowboard/skis in a ski configuration and a snowboarding configuration, as well as a conventional alpine ski, and conventional snowboard according to some embodiments of the present technology;
FIG. 10 illustrates top view of an exemplary binding for coupling with a combination snowboard/skis in a ski configuration and a snowboarding configuration, as well as a conventional alpine ski, and conventional snowboard according to some embodiments of the present technology.
DETAILED DESCRIPTION
Various embodiments of the disclosure are discussed in detail below. While specific implementations are discussed, it should be understood that this is done for illustration purposes only. A person skilled in the relevant art will recognize that other components and configurations may be used without parting from the spirit and scope of the disclosure.
Disclosed is a gliding board that is adapted to split apart to become a pair of downhill skis and further adapted to come together to become a snowboard and which supports boots in both the skier position as well as the snowboarder's position. Some embodiments of the combination snowboard/skis include especially designed connection hardware that facilitates switching between snowboarding mode and skiing mode. Additionally, some embodiments include binding configurations designed to allow snowboarding mode, downhill skiing mode, cross-country skiing, and telemark (alpine touring) skiing.
FIG. 1A illustrates isometric top and side views of a combination snowboard/skis in a snowboard configuration according to some embodiments of the present technology. The combination snowboard/skis comprises three zones: a tip zone 199 , a tail zone 197 , and a central zone 198 . In some embodiments, at least the tip zone 199 is curved up. In some embodiments, both the tip zone 199 and the tail zone 197 are curved upwards. The combination snowboard/skis comprises two gliding boards 111 , 112 coupled together with a tip connector 114 , a tail connector 115 , and two ski connection clip pairings 116 , 116 ′ and 117 , 117 ′. According to FIG. 1A , a set of bindings 130 , 140 are coupled with the combination snowboard/skis via a snowboard binding system (not shown), explained below. Additionally, the individual gliding boards 111 , 112 each include a ski binding plate system 121 , 122 for coupling with the bindings 130 , 140 .
The individual gliding boards 111 , 112 each include two sharpened metal edges 111 a , 111 b , 112 a , 112 b . In some embodiments, all of the edges 111 a , 111 b , 112 a , 112 b comprise a substantially parabolic shape. In the snowboard configuration, edges 111 a and 112 a comprise the snowboard's outer edge configured to facilitate turning the snowboard. Also, the edges 111 b and 112 b form a small channel 160 . In some embodiments, an insert (not shown) is configured to fill the channel 160 and couple with the gliding boards 111 , 112 . In some other embodiments, the one or both of the gliding boards 111 , 112 are configured with a movable flange (not shown) to fill the channel 160 .
FIG. 1B illustrates isometric top and side views of the combination snowboard/skis from FIG. 1A in a ski configuration according to some embodiments of the present technology. The ski configuration illustrated in FIG. 1B involves the position of the gliding boards 111 , 112 swapped such that the curved portions of the tip zone 199 and the tail zone 197 are positioned on the inside edge of a skier's stance. In some other embodiments, the gliding boards 111 , 112 are positioned such that the curved portions of the tip zone 199 and the tail zone 197 are positioned on the outside edge of a skier's stance.
In the snowboard configuration, the set of bindings 130 , 140 were coupled with the combination snowboard/skis via a snowboard binding system comprising two snowboard binding plate systems 151 , 152 .
The snowboard binding plate systems 151 , 152 are each configured with a sub-plate positioned substantially across from another sub-plate on each gliding board 111 , 112 , respectively. As shown, the snowboard binding plate systems 151 comprise sub-plates 151 a and 151 b; likewise, the snowboard binding plate system 152 comprises sub-plates 152 a and 152 b . In some embodiments of the present technology, the position of the sub-plates 151 a , 151 b , 152 a , and 152 b are reconfigurable to allow individual riders to customize their binding positions. For example, in some embodiments, a series of drill holes (not shown) are drilled into the gliding boards 111 , 112 and the sub-plates 151 a , 151 b , 152 a , 152 b coupled with the gliding boards 111 , 112 via the drill holes in a plurality of combinations and arrangements. In some other embodiments, the sub-plates 151 a , 151 b , 152 a , 152 b are in a substantially fixed position and the rider tailors the riding position using a puck system in the sub-plates 151 a , 151 b , 152 a , 152 b or in the bindings themselves. Additionally, some embodiments of the present technology involve binding plate systems that are configured such that the binding system separates in the event of a threshold level of torque being applied, thereby causing the skier's/rider's feet to come free from the board(s) in circumstances that could cause injury to the rider.
In the ski configuration, the set of bindings 130 , 140 are coupled with the combination snowboard/skis via the ski binding plate systems 121 , 122 .
FIG. 2 illustrates various isometric views of an exemplary binding 200 for coupling with a combination snowboard/skis according to some embodiments of the present technology. As shown, the binding 200 includes a slider track 210 configured to slide over the ski binding plate systems (e.g. FIGS. 1A-1B , reference nos. 121 , 122 ) in the ski position and configured to slide over the sub-plates (e.g. FIG. 1B , reference nos. 151 a and 151 b , 152 a and 152 b ) in the snowboard position. The toe edge of the binding 200 includes a stopper plate 220 to prevent the binding 200 from sliding off the slider tracks 210 in one direction of sliding motion. To prevent the binding 200 from sliding off the slider tracks 210 in the reverse direction of sliding motion, the binding 200 configured to accept a locking slide pin (not shown).
In some embodiments of the present technology, the binding 200 is configured with a lockable calf back 216 . The lockable calf back 216 can fold down for convenience and can lock in a rigid upright configuration. Additionally, the binding 200 can include a reconfigurable top strap 249 that can be positioned in a mid-ankle position (as shown) to hold a rider's boot in an ankle-flexing snowboard stance and positioned on the calf back 216 to hold a skier's boot in a high-ankle rigid ski stance.
As explained above, the combination snowboard/skis illustrated in FIGS. 1A-1B have a tip zone 199 and a tail zone 197 which, when in the snowboard configuration, are joined to form a complete semi-circular shape that is typically associated with a snowboard. In ski embodiments of the present technology, the combination snowboard/skis are configured such that the tip zone and the tail zone which, when in the ski configuration, comprise two individual half-semi-circular ski tips.
FIG. 3A illustrates isometric top and side views of a combination snowboard/skis in a ski configuration according to some embodiments of the present technology. The combination snowboard/skis comprises two gliding boards 311 , 312 . The combination snowboard/skis comprises three zones: a tip zone 399 , a tail zone 397 , and a central zone 398 . As shown, the tip zone 399 and the tail zone 397 of each gliding board 311 , 312 comprise two individual semi-circular ski tips typically associated with skis. In some embodiments, at least the tip zone 399 is curved up. In some embodiments, both the tip zone 399 and the tail zone 397 are curved up.
Gliding board 311 is configured with clips 316 , 317 and gliding board 312 is configured with clips 316 ′, 317 ′, where clips 316 , 316 ′ and clips 317 , 317 ′ are configured to connect the gliding boards 311 , 312 when in the snowboard configuration (illustrated below.)
As shown in FIG. 3A , a set of bindings 330 , 340 are coupled with the gliding boards 311 , 312 via ski binding plate systems 321 , 322 . Additionally, the combination snowboard/skis include two snowboard binding plate systems 351 , 352 . The snowboard binding plate systems 351 , 352 are each configured with a sub-plate positioned substantially across from another sub-plate on each gliding board 311 , 312 . As shown, the snowboard binding plate system 351 comprises sub-plates 351 a and 351 b; likewise, the snowboard binding plate system 352 comprises sub-plates 352 a and 352 b . In some embodiments of the present technology, the position of the sub-plates 351 a , 351 b , 352 a , and 352 b are reconfigurable to allow individual riders to customize their binding positions. For example, in some embodiments, a series of drill hole (not shown) are drilled into the gliding boards 311 , 312 and the sub-plates 351 a , 351 b , 352 a , 352 b coupled with the gliding boards 311 , 312 via the drill holes in a plurality of combinations and arrangements. In some other embodiments, the sub-plates 351 a , 351 b , 352 a , 352 b are in a substantially fixed position and the rider tailors the riding position using a puck system in the sub-plates 351 a , 351 b , 352 a , 352 b or in the bindings themselves.
The individual gliding boards 311 , 312 each include two sharpened metal edges 311 a and 311 b , 312 a and 312 b , respectively. In some embodiments, all of the edges 311 a , 311 b , 312 a , 312 b comprise a substantially parabolic shape.
FIG. 3B illustrates isometric top and side views of the combination snowboard/skis from FIG. 3A in a snowboard configuration according to some embodiments of the present technology. In the ski configuration, the set of bindings 330 , 340 were coupled with the gliding boards 311 , 312 via ski binding plate systems 321 , 322 . According to FIG. 3B , the set of bindings 330 , 340 are coupled with the gliding boards via the plate systems 351 , 352 . In the snowboard configuration, edges 311 a and 312 a comprise the snowboard's outer edge configured to facilitate turning the snowboard. Also, the edges 311 b and 312 b form a small channel 360 .
The gliding boards 311 , 312 are coupled in the snowboard configuration with clips 316 , 317 , 316 ′, and 317 ′. In some embodiments of the present technology, the tips and tails of the gliding boards 311 , 312 are also coupled with each other with a jacket, clip, etc. As shown in FIG. 3 , the tips and tails of the gliding boards 311 , 312 are coupled via structural, semi-circular jackets 375 , 377 . The jackets 375 , 377 fit over the tip 399 and the tail zone 397 of the gliding boards 311 , 312 as well as forming tips and tails with a full semi-circular shape typically associated with snowboards. In some embodiments, the jackets 375 , 377 are configured to be partially separated from the tips and tails of the gliding boards 311 , 312 and to be folded over and clipped to one or both of the gliding boards 311 , 312 . In some other embodiments, the jackets 375 , 377 are configured to be completely separated from the tips and tails of the gliding boards 311 , 312 .
FIG. 4A illustrates a method 400 of converting combination snowboard/skis from a snowboard configuration to a ski configuration according to some embodiments of the present technology. The method 400 begins with removing the bindings from the snowboard binding plate systems 402 , decoupling the tip connector and tail connector 404 , and decoupling the ski connection clip pairings 406 . In cases using a structural semi-circular jacket, the method 400 involves removing and storing the jacket 408 .
Next, the method 400 involves positioning the skis in a proper downhill configuration 410 . For example, some embodiments involve swapping the position of the gliding boards relative to the axial length of the boards such that the curved portion of the tips and tails are positioned on the inside edge of the skier's stance, see FIG. 1B . Next, the method 400 involves attaching the bindings to ski binding plate systems 412 .
FIG. 4B illustrates a method 450 of converting combination snowboard/skis from a ski configuration to a snowboarding configuration according to some embodiments of the present technology.
The method 450 begins with removing the bindings from the ski binding plate systems 452 and positioning the gliding boards into a snowboard configuration position 454 . In cases using a structural and semi-circular jacket, the method 450 involves positioning the jacket 456 over the tips and tails of the gliding boards. Next, the method involves coupling the tip connector and tail connector 458 , and coupling the ski connection clip pairings 460 . Finally, the method 450 involves attaching the bindings to ski binding plate systems 462 .
As explained above, some embodiments of the present technology involve binding plate systems that are reconfigurable and are configured such that the binding system separates in the event of a threshold level of torque being applied, thereby causing the skier's/rider's feet to come free from the board(s) in dangerous circumstances.
FIG. 5 illustrates two isometric views of a plate binding system 500 according to some embodiments of the present technology. The plate binding system 500 comprises a top plate 510 with a disk (not shown) extending from its bottom surface and bottom plate 520 having a disk-receiving aperture 525 . The top plate 510 is configured to slide into the slider tracks 210 of the bindings 200 shown in FIG. 2 above, thereby coupling the binding 200 to the plate system 500 . The bottom plate 520 comprises drill holes 515 for attaching the plate binding system 500 to the gliding boards.
The disk (not shown) extending from the bottom surface of the top plate 510 is releasably coupled inside the aperture 525 of the bottom plate 520 via a plurality of pins 353 . The bottom plate 520 also includes a release-setting gauge 530 that displays a setting for the currently selected torque threshold required to separate the disk from the aperture 525 . The bottom plate 520 also includes a set screw (shown in FIG. 6 below) for adjusting the sensitivity of the release settings.
FIG. 6 illustrates an exploded view of a bottom plate 600 of a plate binding system according to some embodiments of the present technology. As shown, the bottom plate 600 comprises a torque-sensitive release mechanism 620 housed within a cavity created by space between cover 610 and cover 630 . The torque-sensitive release mechanism 620 is sealed in the cavity via a plurality of pins 660 and screws 670 . Also housed in the cavity are a settings piston 650 and a piston guide 680 . The settings piston 650 is coupled with and a set screw 640 that is manipulated from outside the cavity. Also, the settings piston 650 is configured to adjust the torque sensitivity settings for the torque-sensitive mechanism 620 upon rotation of the set screw 640 .
FIGS. 7-10 illustrate additional views of an exemplary reconfigurable binding. The binding 700 shown in FIG. 7-10 is substantially similar to the binding shown in FIG. 2 , however, the binding shown in FIGS. 7-10 includes additional features for using the binding with a conventional snowboard or a conventional ski. Binding 700 is configured to receive a conventional snowboard rider style boot. A heel member 710 is designed to accept the rear portion of the rider boot. The rear portion of the rider boot can be placed over cavity formed by the heel member 710 , lockable shin wing 708 , and the reconfigurable binding base 702 . The heel member 710 is connected to the lockable shin wing 708 on one side and the binding base 702 on the other side. In some embodiments, the heel member 710 is moveable as the rider's heel moves in the alpine touring mode. The heel member 710 can slide upwards and downwards as the rider climbs up the uphill to facilitate walking
The feet strap 712 enables a rider boot to enter and exit the reconfigurable binding conveniently. In one embodiment, the feet strap 712 is hinged on one side of the reconfigurable binding and has a latch and hook on the other side of the reconfigurable binding. The latch and the hook enable the rider to tighten or shorten the length of the feet strap 712 to hold the rider boot securely. In other embodiment, the feet strap 712 includes a strap buckle which can be conveniently utilized to tighten the feet strap.
The reconfigurable binding 700 includes a binding base 702 mounted on the gliding board. The binding base includes opening 720 which is configured to receive a cotter pin that secures the reconfigurable binding 700 to the ski binding plate system 121 , 122 in alpine touring ski mode. The binding base also includes opening 722 , which is configured to receive a cotter pin that secures the reconfigurable binding 700 to two snowboard binding plate systems 151 , 152 .
The reconfigurable binding 700 includes side rails 704 underneath the reconfigurable binding 700 . The side rails 704 are configured to slide into a plate rail on the gliding board, thereby coupling the reconfigurable binding 700 to the gliding board.
The reconfigurable binding 700 includes alpine touring connections 706 A 706 B. The alpine touring connection 706 A is positioned in the front of the feet and includes opening 720 . The alpine touring connection 706 B is positioned in the heel area and engages onto the heel of the rider boot. The alpine touring connection 706 B can comprise a series of pins and springs to engage with the movement of the heel of the rider. In alpine touring configuration, when the rider climbs or walks up the mountain, the pins can move along with the rider to disengage the heel of the rider from the binding base 702 for a great degree of freedom.
The reconfigurable binding includes opening 722 for holding the reconfigurable binding in place when the rider is using the reconfigurable binding as a split board. In this configuration a rider will place their boot into the reconfigurable binding. The binding is secured to two snowboard binding plate systems 151 , 152 via side rails 704 , and a pin that is received within opening 722 . The pin also serves to secure the heel of the binding into a fixed position.
Reconfigurable binding is also configured to engage with a traditional alpine ski binding for times when a user doesn't want to use the alpine split board, but instead would like to use traditional alpine skies. In such instances it can be inconvenient to have to change from snowboarding boots into alpine ski boots. The reconfigurable binding 700 removes this impediment by functioning as an alpine ski boot itself. The alpine touring connection 706 A has a front edge having a protruding shape to be received by a toe portion of a conventional alpine ski binding. The alpine touring connection 706 A can be shaped as a toe-shaped to match a shape of the front portion of the ski boot. The rear portion of the alpine touring connection 706 B is shaped to be configured to be received by a heel portion of a conventional alpine ski binding. In some embodiments, the height 705 for the front part of the alpine touring connection 706 A is shorter than the height 707 of the rear part of the alpine touring connection 706 B. This dimension is to be compatible with the traditional alpine ski boots.
The reconfigurable binding 700 can be further configured with a lockable shin wing 708 for “side to side” control in ski mode. The lockable shin wing 708 has a high back that wraps around the shin, thus the skier can have more lateral movement when making turns. The lockable shin wing 708 can fold down for convenience and can lock in a rigid upright configuration. When the skier makes left or right turns, the skier can lean on the lockable shin wing 708 as the entire lockable shin wing 708 will lean with the skier. The lockable shin wing 708 can give more coverage and leverage around shin.
A shin strap slot 714 can be coupled with the lockable shin wing 714 to give more support to the skier. The shin strap can come out of the shin strap slot 714 to have the lockable shin wing to be tightly fixed to the skier's shin. The shin strap can be positioned on a calf position to hold a skier's boot in a high-ankle rigid ski stance. The shin strap can be any elastic or stretchable band. The shin strap may be adhered to the other side of the shin strap by any velcroed material or clip. When the shin strap is not in use, the shin strap can remain in the inside of the lockable shin wing 714 .
FIG. 10 shows a top view of reconfigurable binding 700 . As part of binding base 702 , a series of holes 718 are formed which provide a universal attachment mechanism for interfacing with a traditional snowboard binding. In some embodiments, binding base 702 forms a single opening for receiving an offset multi-disk 716 that provides the universal attachment mechanism for interfacing with one of a plurality of common snowboard bindings.
As described herein, the reconfigurable binding can be used with the alpine split board described herein when the alpine split board is in both split board mode (i.e., snow board configuration and ski mode). The reconfigurable binding is further adapted to be able to be received within a conventional downhill ski binding, wherein the reconfigurable binding functions as part of the rider's boot. Finally, the reconfigurable binding can further be used a binding for a traditional snowboard and alpine touring.
The various embodiments described above are provided by way of illustration only and should not be construed to limit the scope of the disclosure. Those skilled in the art will readily recognize various modifications and changes that may be made to the principles described herein without following the example embodiments and applications illustrated and described herein, and without departing from the spirit and scope of the disclosure.
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Combination ski-snowboard devices reversibly configured in both: a ski configuration comprising two skis each with both an inside and outside edge and a ski binding mounting systems, and in a snowboard configuration having two outside edges and two binding mounting systems. Methods for converting ski-snowboard devices from a snowboard configuration to a ski configuration and from a ski configuration to a snowboard configuration. A reconfigurable binding provides an interchangeable all-in-one binding for at least alpine touring, snowboard, split board and alpine ski mode. One aspect of the reconfigurable binding discloses binding connection adaptable for use in alpine touring and traditional ski mode. Another aspect of the reconfigurable binding discloses a bolt/pin pattern configuration for split board and snowboard mode.
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BACKGROUND OF THE INVENTION
[0001] 1. Field of the Invention
[0002] The present invention relates to a press-head and in particular, but not exclusively to, a press-head of a garment press.
[0003] 2. Description of the Prior Art
[0004] UK Patent 780,660 (Lessing) describes a garment press in which a garment is pressed between two heated plates, the lower plate of which forms a press bed is fixed and the upper plate of which forms a press plate which is mounted to the press bed for movement in a vertical plane only, such that the press plate can be raised from and lowered down onto the press bed. In order to press a garment the press plate is raised, the garment is then placed on the press bed and the press plate lowered into contact with the press bed trapping the garment therebetween in order to effect a pressing operation.
[0005] The press bed of this prior garment press presents a resilient surface to the upper inflexible press plate which permits it to give where required to conform to the shape of buttons or fasteners of the garment being pressed, thereby reducing the incidence of damage to such buttons or fasteners when pressed between the two plates. For this purpose the fixed press bed of this prior garment press comprises two substantially parallel plates, an upper perforated plate which forms the pressing surface on which the garment is supported and a lower support surface in the form of a grid plate. The resilience of the press bed is provided by a number of conical springs arranged in longitudinal rows and secured between the grid and perforated plates of the press bed.
[0006] This type of garment press is only designed to press garments by trapping the garment between its two plates and is therefore not suitable for pressing garments having a complicated structure such as for example shirts, for such garments, care has to be taken when pressing one part of the shirt that creases are not introduced into another part of that shirt, and to ensure that the seams and edges such as collars and cuffs are sharp and crisp. This prior garment press is generally only designed for dealing with newly made garments which have been laundered but not dried, since creases introduced during the drying process cannot be effectively removed.
[0007] In order to effectively press laundered dried garments it is known to use a hand held heated iron which is pressed to the surface of the garment and moved about the surface thereof by an operator in order to smooth out the creases. This method however causes considerable operator fatigue, and results in poor efficiency and economic performance. In order to overcome this problem a garment press was developed as described in UK Patent GB 2 318 591 (Barry James Freeman) in which the known press plate is replaced by a press-head which can be moved about the garment in a similar fashion to a hand held heated iron, but which press-head is supported by the garment press with the garment press providing mechanical advantage to the movement of the press-head. This has the advantage of alleviating operator fatigue.
[0008] The garment press of GB 2 318 591, as illustrated in FIG. 8 of the present drawings, comprises a fixed press table 18 for supporting a garment to be pressed and a moveable press-head 58 which is brought into contact with the press table 18 for pressing the garment. For this purpose the press-head 58 fixedly depends from one end of a press shaft 50 , which shaft forms a lifting axis for the press-head 58 in order to raise and lower the press-head 58 away and towards the pressing table 18 . The press shaft 50 extends vertically through a bearing in a yoke frame 44 so as to be capable of both rotational and linear movement. Pneumatic cylinders 54 provided either side of the yoke 44 can be activated by means not illustrated to impose linear motion of the shaft 50 through the yoke to raise and lower the press-head 58 , whilst handle 60 fixed to the shaft 50 is used to manually rotate the shaft 50 about its lifting axis and thereby rotate the press-head 58 relative to the pressing surface 18 . Additionally, the press-head 58 is also moveable in a substantially horizontal plane across the press table due to its mounting on transverse bars 40 which are mounted for slidable movement on fixed horizontal bars 34 . Handle 64 fixed to horizontal bars 34 is used to manually slide the press-head transversely to bars 34 and along bars 34 , thereby moving the press-head about the surface of the pressing table.
[0009] This prior press-head has the disadvantage that the press-head is a rigid body and therefore does not readily adapt to press garments having different thicknesses, or garments supporting trimmings such as buttons or fastenings without operator assistance in adjusting the position of the press-head above the table. Without adjustment thicker parts of the garment may be overpressed, and thinner parts of the garment may be underpessed, also button damage may occur. Whilst a degree of adjustment can be achieved by providing a padded surface to the press table without hindering the free movement of the press-head across the press table, there nevertheless exists the need to provide automatic adjustment alleviating the need for operator involvement. It would not be appropriate to provide rows of conical springs, such as used in the fixed press plates of GB 780 660 (Lessing) because compression of these springs would block the movement of the press-head.
SUMMARY OF THE INVENTION
[0010] It is an object of the present invention to provide a press-head which overcomes or alleviates the above described drawbacks.
[0011] It is a further object of the present invention to provide an improved press-head for a garment press which more effectively presses textile items such as garments having varying thicknesses and/or trimmings.
[0012] To this end, the subject of the present invention is a press-head which can be installed and fitted on a garment press, and which can be mechanically assisted in its movements about a pressing surface of the garment press. A further subject of the present invention is a garment press incorporating such a press-head.
[0013] According to the present invention there is provided a press-head having a self-levelling mechanism which automatically adjusts the position of the press-head when the press-head encounters a variation in thickness of an item being pressed by the press-head when the press-head encounters a variation in thickness of an item being pressed by the press-head when the press-head is moved over the item.
[0014] Advantageously the self adjusting mechanism may be provided between a main body of the press-head and its sole plate, the self adjusting means tilting the sole plate when said variation in thickness is encountered. The self adjusting mechanism may comprise resilient means which extend between the main body of the press-head and its sole plate. The self adjusting mechanism may comprise a plurality of pins which stand proud of the sole plate which pins are retained slidably and tiltably by the main body. Advantageously, a spring may be provided about each pin which extends between the main body and the sole plate. Advantageously, the press-head has means to connect it to a lifting shaft of a garment press and the pins may be provided in a symmetrical array relative to that shaft.
DESCRIPTION OF THE DRAWINGS
[0015] The invention will be described by way of example only and with reference to the accompanying drawings in which:
[0016] [0016]FIG. 1 shows a schematic side view of a press-head constructed in accordance with a first embodiment of the present invention;
[0017] [0017]FIG. 2 shows a plan view of the press-head of FIG. 1;
[0018] [0018]FIG. 3 is a view similar of FIG. 1 illustrating tilting of the sole plate of the press-head when encountering an obstruction located centrally in the path of movement of the press-head;
[0019] [0019]FIG. 4 shows a front view of the press-head of FIG. 1;
[0020] [0020]FIG. 5 is a view similar to FIG. 4 illustrating movement of the sole plate of the press-head when encountering an obstruction located to one side in the path of movement of said press-head;
[0021] [0021]FIG. 6 is a view similar to FIG. 1 of a second embodiment of press-head;
[0022] [0022]FIG. 7 is a plan view of the press-head of FIG. 6; and
[0023] [0023]FIG. 8 is a schematic view of a known garment press.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0024] FIGS. 1 to 5 show a first and non-limiting embodiment of press-head constructed in accordance with the present invention for pressing a garment placed on a pressing surface of a pressing table. The press-head is in use mounted above the table for vertically liftable movement towards and away from the pressing surface in order to bring the press-head into engagement with the garment, and for movement in a horizontal plane about the pressing surface in order that the press-head can be moved about the surface of the garment to smooth out any creases. For this purpose the press-head in this embodiment has means to mount it to a press shaft of a garment press such as that described in UK Patent GB 2 318 591 (Barry James Freeman).
[0025] The press-head 58 comprises two substantially parallel plates 17 , 10 , in the form of a fixed pressure plate 10 which is adapted to be fixedly connected to a press shaft 50 of a garment press for movement therewith, and a dependent sole plate 17 which is suspended from the fixed pressure plate 10 .
[0026] The pressure plate 10 has three through bores 1 provided in a row along its central axis 2 . The sole plate 17 carries three corresponding, upwardly extending fixed pins 20 which are located in a row along its central axis 3 . Each pin 20 has a cross-section which is slightly smaller than that of the bores 1 and are moveably located through a respective bore 1 . The sole plate 17 is retained on the pressure plate 10 by the provision of circlips 13 , which have a cross-section wider than that of the bores and which are provided on the free ends of the pins 20 at the side 4 of the pressure plate 10 remote from the sole plate 17 . In its rest position, that is when the press-head 58 is not in a pressing position, the circlips 13 rest on outer surface 4 of pressure plate 10 , with the sole plate 17 hanging thereon.
[0027] A spring 15 is provided about each pin 20 and extends between the pressure plate 10 and the sole plate 17 . Each spring 15 has a cross-section which is wider than its respective bore 1 to prevent the spring extending through the bore 1 .
[0028] In use when the press shaft 50 is moved downwards the pressure plate 10 fixed thereto is moved down towards the pressing surface of the pressing table. The sole plate 17 , suspended by circlips 13 on the pressure plate 10 , is likewise lowered down towards the pressing surface. Once the sole plate 17 contacts the pressing surface further downward movement of the pressure plate moves the pressure plate 10 downwards along pins 20 (as best illustrated in FIG. 3) which increases the tension of springs 15 as the gap between the pressure plate and sole plate decreases and thereby increases the downward pressure of the sole plate 17 on the surface of the item to be pressed.
[0029] Movement of the press-head along the surface of the garment enables the smoothing of creases with pressure from the pressure plate 10 via the springs 15 keeping the surface of the sole plate evenly pressed to the garments surface. However, when the sole plate encounters an uneven surface 5 to the garment, the sole plate 17 is able to lift from the garments surface, and effectively ride over such obstruction.
[0030] As best illustrated in FIG. 3 if an obstruction 5 is encountered by the sole plate 17 , which obstruction in this instance is located in line with the central axis 3 of the sole plate 17 , the leading edge 6 of the sole plate 17 is lifted as it contacts the obstruction due to further and upward compression of the leading spring 15 A, causing lifting and tilting of pin 20 A within its bore 1 A. Once the portion of the sole plate carrying pin 20 A has passed the obstruction, this additional force to the spring 15 A is released and the leading edge 6 of the sole plate 17 is once again forced down to the pressing surface by the pressure exerted by the pressure plate 10 . As the sole plate 17 passes over the obstruction each spring 15 B, then 15 C is progressively compressed and then released enabling the sole plate to ride over the obstruction.
[0031] [0031]FIG. 5 illustrates the reaction of the sole plate 17 when it encounters an obstruction 5 located in its path, but to one side of the sole plate 17 . In this instance as the sole plate encounters the obstruction the sole plate is lifted from the side causing a progressive lift and tilt to each of the pins 20 A, 20 B, 20 C as springs 15 A, 15 B and 15 C are compressed, and then released once the obstruction has passed from under the sole plate 17 .
[0032] The springs provide a cushioning effect by adjusting the pressure exerted by the press-head on to the pressing surface, enabling a self adjustment of the press-head when it encounters an obstruction, thereby reducing damage to items such as buttons and self adjusting the pressure it exerts enabling a more uniform pressing when different thicknesses of garment are encountered during movement of the press-head about the pressing surface. This eliminates or reduces the need for the operator to make appropriate adjustments.
[0033] [0033]FIGS. 6 and 7 show a second and non-limiting embodiment of press-head constructed in accordance with the present invention. This embodiment of press-head is similar to that of FIGS. 1 to 5 , but in this embodiment the sole plate 17 is supported by four pins 20 each with a spring 15 . In this arrangement two of the pins 20 D, 20 E are provided in line with the central axis 2 , 3 , one either side of the press-head lifting axis provided by press shaft 50 and with pin 20 D spaced further from the shaft 50 to provide greater stability to the longer front end 6 of the sole plate 17 .
[0034] Whilst the other two pins 20 F and 20 G are provided in line transversely to the central axis 2 , 3 and in parallel with and equally spaced from said lifting axis 50 . As before corresponding bores are provided in the pressure plate 10 through which the pins 20 D, 20 E, 20 F and 20 G are mounted to suspend the sole plate 17 . This arrangement functions in the same manner as the pin arrangement described with respect to FIGS. 1 to 5 when the press-head moves across the pressing surface, but holds the sole plate more firmly when the sole plate is in the non-pressing position.
[0035] It is to be understood that the invention is not limited to the specifically described pin arrangements and other arrangements of pins will be apparent to one skilled in the art which will enable the self levelling of the sole plate of the pressing head.
[0036] It is to be noted that the sole plate may be heated by suitable known means.
[0037] Also, it should be noted that the spring force of the springs can be selected to provide a certain pretension between the pressure plate and the sole plate to achieve a required pressing force and/or the press-head can be lowered to a predetermined level to compress the springs to a desired tension to adjust the pressing force of the press-head.
[0038] Although the press-head has been described as being mounted to a garment press as described in UK Patent GB 2 318 591, it could be provided to other types of garment press which enable movement in alternative ways about the pressing surface while the invention has been described in detail and in terms of specific embodiments thereof, it will be apparent that various changes and modifications can be made therein by one skilled in the art without departing from the spirit and scope thereof.
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A press-head with a self-levelling mechanism automatically adjusts the position of the press-head when it encounters a variation in thickness of an item being pressed. In the preferred embodiment, the mechanism includes a plurality of pins which stand proud of the sole plate and are retained slidably and tiltably by the main body. Advantageously, a spring may be provided about each pin between the main body and the sole plate. The press-head has means for connecting it to a lifting shaft of a garment press and the pins may be arranged in a symmetrical array relative to that shaft.
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CROSS REFERENCE TO RELATED APPLICATIONS
[0001] This application claims priority from United Kingdom Application 0905027.9 filed Mar. 24, 2009, which is hereby incorporated by reference in its entirety.
BACKGROUND OF THE INVENTION
[0002] This invention relates to flying apparatus and a method of use thereof.
[0003] Although the following description refers almost exclusively to hovering flying apparatus in the form of a toy quadcopter or quadrotor, it will be appreciated by persons skilled in the art that the present invention can relate to any suitable flying apparatus with any number of rotors, whether it be a toy or full size flying apparatus.
[0004] It is known to provide flying or hovering apparatus in the form of a quadcopter or quadrotor. This is a type of aircraft which is lifted and propelled by four sets of rotors. Control of motion of the aircraft can be achieved by varying the relative speed of each rotor to change the thrust and torque produced by each rotor.
SUMMARY OF THE INVENTION
[0005] An example of a conventional quadrotor aircraft 2 is shown with reference to FIG. 1 . The aircraft 2 includes a central body 4 with four elongate arms 6 , 8 , 10 , 12 protruding outwardly therefrom to form a substantially cruciform shaped frame when viewed in plan. A rotor 14 is provided at the free end of each arm 6 - 12 and each rotor 14 is capable of undergoing rotational movement about a substantially vertical axis 16 . Oppositely mounted rotors 14 are rotatable in the same direction and adjacently mounted rotors 14 are rotatable in opposite directions. Thus, two rotors move in a clockwise direction 18 and two rotors move in an anti-clockwise direction 20 in use of the aircraft. The torque reactions provided by driving the rotors balance, and the aircraft does not tend to spin about its central axis. Control electronics (not shown) are located in central body 4 and are typically controlled remotely via a remote control handset. A motor is associated with each rotor to allow independent control of the same.
[0006] The above described arrangement allows movement of the aircraft 2 to be controlled in three axes, by varying the speed of each rotor 14 . For example, to pitch the aircraft forwards, the speed of the front rotor is reduced and the speed of the rear rotor is increased. To roll the aircraft to the right, the speed of the right rotor is reduced and the speed of the left rotor is increased. To yaw the aircraft to the right, the speed of the front and rear rotors are reduced and the speed of the left and right rotors are increased. This creates an imbalance in the torque reaction which causes the aircraft to rotate but does not create a tilt force and does not affect the overall lift of the aircraft.
[0007] Although the above described aircraft works in principle, most designs are small in size and result in rapid responses to control inputs, thereby making it difficult for a user to control. In order to overcome this problem, electronic motion sensors or gyroscopes are used to detect rotation in each of the three axes of movement (pitch, roll and yaw). These sensors provide direct negative feedback to the rotor motors to dampen the aircraft's rotational motion and help control the stability of the same. The sensors typically form part of the electronic control system mounted in the central body of the aircraft.
[0008] It is an aim of the present invention to provide flying apparatus which provides an improved level of stability.
[0009] It is a further aim of the present invention to provide a method of using flying apparatus having an improved level of stability.
[0010] According to a first aspect of the present invention there is provided flying apparatus, said apparatus including a housing with two or more rotor means associated therewith, said rotor means arranged to rotate about substantially parallel axes in use and wherein one or more vanes are provided with said apparatus to help stabilize the apparatus in use.
[0011] The one or more vanes perform two main stabilizing functions; firstly they provide drag to prevent tilt of the apparatus and secondly the drag provides damping against oscillation movement of the apparatus.
[0012] Preferably the two or more rotor means are located a spaced distance apart and arranged so as to balance the apparatus in use. For example, each rotor means can be located equal spaced distances apart from each other. The rotor means are preferably located in substantially the same vertical position with respect to the apparatus.
[0013] Preferably the two or more rotor means are arranged a pre-determined radial distance from a central body or point of said apparatus. The pre-determined radial distance is preferably substantially the same for each rotor means.
[0014] Preferably the two or more rotor means are located on or associated with a frame of said apparatus. Further preferably each rotor is located at or adjacent a peripheral edge or corner of said frame.
[0015] In one embodiment the frame is in the form of a cruciform shape when viewed in plan. For example, a plurality of elongate arms can protrude outwardly from a central body or point and rotor means can be provided at or adjacent a free end of each of said elongate arms.
[0016] In one embodiment the frame is in the form of a square shape when viewed in plan and each rotor means can be provided at or adjacent a corner of said frame.
[0017] Preferably the frame means are substantially rigid in form.
[0018] In one embodiment the apparatus includes at least three rotor means and in a preferred embodiment the apparatus includes four rotor means.
[0019] Preferably each rotor means is rotatable about a substantially vertical axis in use.
[0020] Preferably each rotor means includes two or more rotor blades and preferably said rotor blades are arranged to rotate about a substantially vertical axis.
[0021] Preferably the one or more vanes are located above, and preferably a spaced distance above the rotor means of the apparatus.
[0022] Preferably the number of vanes provided on the apparatus equals the number of rotor means provided on said apparatus.
[0023] In one embodiment the vanes are orientated substantially parallel to the frame members associated with each of the rotor means.
[0024] Preferably each vane is substantially flat or in a sheet like form. The vane is arranged in a substantially vertical plane or in a plane substantially parallel to the axis about which said rotor means rotate in use.
[0025] In one embodiment each vane has a first end which is joined to or adjacent a first end of a further vane, and a second free end.
[0026] In one embodiment the first ends of each vane are located at or adjacent a substantially central axis of the apparatus and protrude outwardly or radially from said central axis.
[0027] In one embodiment each vane spans substantially the entire diameter of the apparatus, housing or frame. If two or more vanes are provided, the vanes are typically arranged to be substantially equal distance apart from each other or in such orientation to allow balancing of the apparatus in use. For example, two vanes can be used which slot together to form a cruciform shape when viewed in plan. One or more slits or slots can be defined in the vanes to allow slotting of the same together.
[0028] The size, shape and/or height of the one or more vanes can be adjusted to alter the stability of the apparatus as required.
[0029] The vanes can be integrally formed, attached or detachably attached to the apparatus, frame or housing. The attachment means for allowing the attachment or detachable attachment of the one or more vanes include any or any combination of adhesive, welding, one or more clips, slots, hook and loop fastening, screws, inter-engaging means, friction fit and/or the like.
[0030] Preferably control means are contained in, provided on or associated with the housing. The control means allow control of the rotor means and preferably the rotor means are each independently controlled via the control means.
[0031] Preferably the flying apparatus is controlled remotely via remote control means, such as for example by a remote controlled handset operable by a user. The control means can communicate with the remote controlled handset via infra red, radio frequency and/or the like. Suitable transmitter and/or receiving means can be associated with the apparatus and/or the remote controlled handset as required to allow control signals to be passed between the handset and the flying apparatus.
[0032] Preferably the control means includes one or more motion sensors. Yet further preferably the motion sensors are capable of detecting pitch, roll and/or yaw of the apparatus.
[0033] In one embodiment of the present invention the rotor means are located at or adjacent a base of the apparatus or below said housing.
[0034] In one embodiment one or more support feet can be provided on or associated with a base of said apparatus, frame or housing to support the apparatus when on a surface, such as for example in an “out of use” position. The support feet typically protrude below the rotor means.
[0035] In one embodiment one or more wheels, rollers or other suitable movement means are provided at or adjacent the base of the apparatus to allow the apparatus to be moved across a surface, such as a ground or floor surface in use.
[0036] Preferably the flying apparatus is in the form of a hovering or non-spinning apparatus and yet further preferably the flying apparatus is in the form of a toy for use by a child or adult.
[0037] Preferably the flying apparatus is in the form of a quadrotor.
[0038] Preferably suitable drive means are provided to allow driving of the rotation of the rotor means. The drive means can include a motor, suitable gearing and/or the like.
[0039] Preferably power means are provided to allow powering of the drive means. The power means can include a mains power supply, battery power, rechargeable battery power and/or the like.
[0040] The two or more rotor means can be arranged in substantially the same horizontal plane, in an adjacent or side by side manner or can be arranged in a stacked manner, such as coaxially, with one rotor means located above or below a further rotor means.
[0041] According to a second aspect of the present invention there is provided a method of using flying apparatus, said apparatus including a housing with two or more rotor means associated therewith, said method including the step of rotating said rotor means about substantially parallel axes and wherein one or more vanes are provided with said apparatus to help stabilize the apparatus in use.
[0042] According to further aspects of the present invention there is provided a quadrotor and a method of using a quadrotor.
BRIEF DESCRIPTION OF THE INVENTION
[0043] An embodiment of the present invention will now be described with reference to the following figures, wherein:
[0044] FIG. 1 shows an example of a prior art quadrotor aircraft in plan view;
[0045] FIG. 2 is a perspective view of a quadrotor aircraft according to an embodiment of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
[0046] Referring to FIG. 2 , there is illustrated a quadrotor 100 according to an embodiment of the present invention. The quadrotor 100 has a central body portion 102 containing electronic control means. Frame means in the form of four elongate arm members 104 protrude radially outwardly from body portion 102 . Each arm member is spaced equidistance apart and is of substantially equal length. The arm members are arranged to form a substantially cruciform shape when viewed in plan from above.
[0047] Rotor means in the form of four rotors 106 are located at the free ends of each arm member 104 . Each rotor 106 includes two rotary blades 108 , 110 rotatable about a substantially vertical axis. A motor 114 is associated with each rotor 106 at the free end of each arm 104 . The motors 114 are connected or communicate with the electronic control means provided in the central body portion 102 to allow control of the rotation of each of the rotors. The rotors 106 are operable using the control means and a remote control handset in a similar manner to the prior art device described in FIG. 1 .
[0048] Support feet 112 are provided to protrude from a base of body portion 102 for supporting the quadrotor on a ground surface, such as for example a substantially horizontal surface in use.
[0049] In accordance with the present invention, there are provided four stabilizing vane members 116 to help stabilize the quadrotor in use. Each vane member 116 has a first end 118 which is attached to a first end of an adjacent vane member at a substantially central vertical axis of the apparatus, and a second end 120 which is located adjacent rotor 106 at a peripheral edge of the apparatus.
[0050] Each vane member 116 is in a sheet like form with a height substantially greater than a width thereof in the illustrated example. The vane members 116 can be any suitable shape but in the illustrated example the top section or top edge of the vane member is substantially curved or convexed in shape.
[0051] The vane members can be substantially rigid or flexible in form providing they offer some degree of stability to the apparatus.
[0052] Each vane member typically protrudes radially from a central point of the apparatus and, in the illustrated example, are substantially parallel to the frame members 104 .
[0053] Four separate vane members can be provided or two vane members can be provided which span between two oppositely located rotors.
[0054] The vane members help the apparatus to be automatically self leveling in use. The vane members are located above the rotors and extend above the top of the body portion where the electronic control means are located. The vane members are thin and formed from light weight material. The vane members provide a large amount of aerodynamic drag during horizontal movement of the apparatus. For example, the vane members arranged between the front and rear of the apparatus provide drag against sideways movement of the apparatus in use. The vane members arranged between the left and right of the apparatus provide drag against fore-aft movement of the apparatus in use.
[0055] The vanes perform two main functions. Firstly, because the vanes are mounted at the top of the apparatus, the drag generated by the vanes tends to tilt the apparatus in the opposite direction to any horizontal movement undertaken by the apparatus. This provides a form of negative feedback, tending to keep the apparatus in a substantially horizontal, stationary hover. Secondly, the drag provides damping against substantially horizontal movement undertaken by the apparatus. This is important, otherwise the feedback affect from the vanes would cause the apparatus to oscillate back and forth in a pendulum type of motion. Although the two functions are provided by a pair of vanes or four vanes, the magnitude of the effect can be varied independently by changing the size of the vanes (which adjusts both effects together) and/or the height of the vanes (which alters the amount of tilt feedback but not the amount of horizontal damping).
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Flying apparatus is provided including a housing with two or more rotor means associated therewith. The rotor means are arranged to rotate about substantially parallel axes in use. One or more vanes are provided with said apparatus to help stabilize the apparatus in use.
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[0001] This application is a continuation-in-part of application Ser. No. 10/835,397, filed Apr. 30, 2004, and the entire contents of which is hereby incorporated by reference.
FIELD OF THE INVENTION
[0002] The present invention relates to a method of measuring skin cholesterol. More particularly, the invention pertains to a method for the direct assay of cholesterol in skin samples removed by tape stripping, with a view to identifying individuals at risk of having atherosclerosis as well as those at risk of developing atherosclerosis and similar diseases associated with and attributable to high cholesterol levels.
BACKGROUND OF THE INVENTION
[0003] Numerous studies have shown that atherosclerosis and its complications, such as heart attacks and strokes, are major causes of morbidity and mortality in almost all countries of the world.
[0004] Cost effective prevention of atherosclerosis requires the identification of individuals at risk, thereby allowing their medical treatment and change of life style. A desired goal is identifying those individuals belonging to the high-risk group but there are difficulties in selecting optimum methods for discriminating individuals at risk.
[0005] A widely used method for identifying individuals at risk of having atherosclerosis is based on the measurement of total cholesterol levels in venous blood plasma (Consensus Conference on Lowering Blood Cholesterol to Prevent Heart Disease, JAMA, 1985, 253, pg. 2080). Patients are considered to be at high-risk if their cholesterol level is over 240 mg/dL and there have been recent moves to lower this threshold level to lower values.
[0006] However, total cholesterol levels alone do not accurately predict a patient's risk level. A better prediction can be made by analyzing blood plasma lipoproteins; in particular, measurement of low density and high-density lipoprotein (HDL) cholesterol levels is advantageous (Total and High Density Lipoprotein Cholesterol in the Serum and Risk of Mortality, British Medical Journal, 1985, 290, pg. 1239-1243).
[0007] Despite their advantage, use of the above methods requires blood sampling after a period of fasting. Additionally, the sampling is uncomfortable, poses a risk of infection and the required analysis of plasma lipoproteins and cholesterol is complicated and expensive. Moreover, studies have shown that blood plasma analysis may not entirely reflect the process of cholesterol accumulation in the arterial wall and other tissues. In many cases, neither plasma cholesterol levels nor even complete lipid profiles correlate with the severity of atherosclerosis.
[0008] Significant levels of cholesterol occur in tissue as well as in plasma and it has been shown that tissue cholesterol plays a leading role in development of atherosclerosis. Tissues, including skin, have been identified which accumulate cholesterol in the same way as the arterial wall and studies have demonstrated a close correlation between cholesterol content in the arterial wall and the skin. For example, cholesterol was extracted from lyophilized skin samples and measured using traditional chemical and biochemical techniques. (Nikitin Y. P., Gordienko I. A., Dolgov A. V., Filimonova T. A. “Cholesterol content in the skin and its correlation with lipid quotient in the serum in normals and in patients with ischemic cardiac disease”, Cardiology, 1987, II, No. 10, P 48-51). While useful, this method is too complicated and painful to be employed for large scale population screening.
[0009] U.S. Pat. No. 4,458,686 describes a method of quantifying various compounds in the blood directly under the skin or on its surface. The method is based on measuring oxygen concentration changes electrochemically, for instance, via polarography. In the case of non-volatile substances that do not diffuse through the skin, it is necessary to implant enzymes under the skin to effect oxygen changes at the skin surface. This patent also discloses the potential of using such methods to quantify the amount of cholesterol using cholesterol oxidase. The complex instrumentation and procedures needed require the services of highly skilled personnel for making measurements, thus limiting the usefulness of the method for screening large numbers of people.
[0010] Determination of the cholesterol content in skin gives a measure of the extent of atherosclerosis and can be obtained through standard laboratory analysis of skin biopsy specimens. However, there is considerable pain involved in taking a skin sample and a risk of infection at the sampling site. In addition; this method has other disadvantages because the thick skin specimens incorporate several skin layers, including the outermost horny layer (stratum corneum), epidermis and dermis. Since the dermal layer is highly vascularized, skin biopsy samples contain blood vessels and blood elements. They may also contain sweat and sebaceous glands and the secretions contained therein. Additionally, subcutaneous fat is located directly under the derma and may also contaminate specimens. Therefore, skin biopsy specimens are heterogeneous and their analysis may give false data on cholesterol content in the skin.
[0011] U.S. Pat. No. 5,489,510 describes a non-invasive method for the visual identification of cholesterol on skin using a reagent having a specific cholesterol binding component in combination with a reagent having an indicator component to provide a visual color change corresponding to the presence of the component bound to cholesterol of the skin. The method overcomes many of the objections of earlier procedures and meets many of the desired goals required for a simple mass screening to identify individuals at risk of having atherosclerosis. The procedure is done directly on the palmar skin and, while it is quick and simple, it requires all individuals to be tested to be present at a doctor's office or clinic where the test is conducted. This of course limits effective large scale screening.
[0012] Molar ratios of the lipids, including cholesterol, in stratum corneum have been determined on samples obtained by direct, solvent extraction of skin (Norlen L., et al. J. Invest. Dermatology 72-77, 112, 1999). High performance liquid chromatography (HPLC) and gas liquid chromatography in conjunction with mass spectrometry were used to separate and analyze the lipids. The analytical methods are complex, but more importantly, the use of corrosive and irritant organic solvent systems to extract human skin for routine determinations is not practical.
[0013] The lipid profile of the stratum corneum layer of skin has been determined using a tape stripping method as described by A. Weerheim and M. Ponec (Arch. Dermatol. Res., 191-199, 293, 2001). In this study, lipids, including cholesterol, were solvent extracted from stratum corneum after tape stripping of skin. The resultant lipid extract was separated by high performance thin-layer chromatography. This method is very laborious. It requires three consecutive solvent systems to effect the separation of the lipids, a staining and charring method to visualize the components and a densitometry step to determine the relative amounts of the lipids. The method does not lend itself to the simple and rapid determination of cholesterol levels in large numbers of samples.
SUMMARY OF THE INVENTION
[0014] It is therefore an object of the present invention to overcome the above drawbacks and to provide a simple and non-invasive method of measuring skin cholesterol, which allows for effective large scale screening.
[0015] According to a first aspect of the invention, there is provided a method of measuring skin cholesterol, which comprises the steps of:
a) providing a tape comprising a backing member coated on at least one side thereof with a medical adhesive; b) applying the tape onto a selected area of skin to adhere the tape to the selected skin area; c) stripping the tape off the selected skin area to obtain a sample representative of an outer stratum corneum layer of the skin, the sample adhering to the tape so as to have exposed skin constituents; d) providing a source of an affinity-enzymatic compound of formula A-C-B, wherein A is a detecting agent having affinity for cholesterol, B is an enzymatic visualizing agent and C is a binding agent linking the detecting agent and the visualizing agent to one another; e) applying a predetermined amount of the affinity-enzymatic compound onto a predetermined surface area of the sample and allowing the compound to remain in contact therewith for a period of time sufficient to cause binding of the detecting agent to cholesterol present in the exposed skin constituents; and f) applying a predetermined amount of a color developing agent onto the predetermined surface area of the sample, whereby the color developing agent reacts with the enzymatic visualizing agent to form a colored product having a color indicative of cholesterol level.
[0022] The detecting agent in the aforesaid method is selected from the group consisting of steroid glycosides, triterpene glycosides, hydrophobic proteins, polyene antibiotics and anti-cholesterol antibodies. In one aspect of the invention, the detecting agent is a steroid glycoside, and the steroid glycoside is digitonin.
[0023] Further, in the aforesaid method, the enzymatic visualizing agent is an enzyme selected from the group consisting of peroxidase, alkaline phosphatase, urease, galactosidase, glucose oxidase and acetylcholinesterase. In one aspect of the invention, the enzyme is peroxidase, and the peroxidase is horseradish peroxidase.
[0024] In a further aspect of the invention, after step (e) the peroxidase is activated with hydrogen peroxide to form an activated peroxidase, and wherein the color developing agent used in step (f) reacts with the activated peroxidase to form the colored product.
[0025] In a further aspect of the invention, in step (f) a predetermined amount of an aqueous solution containing hydrogen peroxide and the color developing agent is applied onto the predetermined surface area of the sample.
[0026] The color developing agent is selected from the group consisting of 2,2′-azino-di-(3-ethylbenzthiazoline-6-sulfonic acid) and 3,3′,5,5′-tetramethyl benzidine. In a particular aspect of the invention, the color developing agent is 3,3′,5,5′-tetramethyl benzidine.
[0027] The binding agent is a copolymer of maleic anhydride and N-vinylpyrrolidone.
[0028] Moreover, the backing member of the tape is formed of polyester. The medical adhesive is a pressure-sensitive adhesive. In one aspect of the invention, the medical adhesive is an acrylic based adhesive. In another aspect of the invention, the medical adhesive is a synthetic rubber elastomer adhesive. In yet a further aspect of the invention, the medical adhesive is a silicone based adhesive. In a further aspect, the medical adhesive comprises an elastomer formed of block polymers of styrene-isoprene-styrene or styrene-butadiene-styrene.
[0029] According to a second aspect of the invention, there is provided a method of measuring skin cholesterol, which comprises the steps of:
a) providing a tape comprising a backing member coated on at least one side thereof with a medical adhesive; b) applying the tape onto a selected area of skin to adhere the tape to the selected skin area; c) stripping the tape off the selected skin area to obtain a sample representative of an outer stratum corneum layer of the skin, the sample adhering to the tape so as to have exposed skin constituents; d) providing a source of an affinity signal-generating compound of formula A-C-B′, wherein A is a detecting agent having affinity for cholesterol, B′ is a signal-generating indicator agent and C is binding agent linking the detecting agent and the indicator agent to one another; e) applying a predetermined amount of the affinity signal-generating compound onto a predetermined surface area of the sample and allowing the compound to remain in contact therewith for a period of time sufficient to cause binding of the detecting agent to cholesterol present in the exposed skin constituents; and f) measuring the signal generated by the indicator agent to provide a value indicative of cholesterol level.
[0036] The detecting agent in the aforesaid method is selected from the group consisting of steroid glycosides, triterpene glycosides, hydrophobic proteins, polyene antibiotics and anti-cholesterol antibodies. In one aspect of the invention, the detecting agent is a steroid glycoside, and the steroid glycoside is digitonin.
[0037] The indicator agent in the aforesaid method is selected from the group consisting of dyes, fluorophores, radioisotopes, metal sol compounds and chemiluminescent compounds. In one aspect of the invention, the indicator agent is a dye. In another aspect of the invention, the indicator agent is a fluorophore. In a further aspect of the invention, the indicator agent is a radioisotope. In another aspect of the invention, the indicator agent is a metal-sol compound. In a further aspect of this invention the indicator agent is a chemiluminescent compound.
[0038] Moreover, in one aspect of the invention, step (f) is carried out by spectrophotometry. In another aspect of the invention, step (f) is carried out by colorimetry. In yet a further aspect of the invention, step (f) is carried out by fluorometry. A further aspect of the invention has step (f) is carried out by means of a radioactivity sensor. In a further aspect of this invention, step (f) is carried out by luminometry.
[0039] In the aforesaid method the binding agent is a copolymer of maleic anhydride and N-vinylpyrrolidone.
[0040] Moreover, the backing member of the tape is formed of polyester. The medical adhesive is a pressure-sensitive adhesive. In one aspect of the invention, the medical adhesive is an acrylic based adhesive. In another aspect of the invention, the medical adhesive is a synthetic rubber elastomer adhesive. In yet a further aspect of the invention, the medical adhesive is a silicone based adhesive. In a further aspect, the medical adhesive comprises an elastomer formed of block polymers of styrene-isoprene-styrene or styrene-butadiene-styrene.
[0041] According to a third aspect of the invention, there is provided a method of measuring skin cholesterol, which comprises the steps of:
a) providing a tape comprising a backing member coated on at least one side thereof with a medical adhesive; b) applying the tape onto a selected area of skin to adhere the tape to the selected skin area; c) stripping the tape off the selected skin area to obtain a sample representative of an outer stratum corneum layer of the skin, the sample adhering to the tape so as to have exposed skin constituents; d) providing a source of cholesterol oxidase as a detecting agent having affinity for cholesterol; e) applying a predetermined amount of cholesterol oxidase onto a predetermined surface area of the sample and allowing the cholesterol oxidase to remain in contact therewith for a period of time sufficient to cause oxidation of cholesterol and formation of hydrogen peroxide; and f) measuring the amount of hydrogen peroxide formed in step (e), the amount of hydrogen peroxide measured being indicative of cholesterol level.
[0048] In one aspect of the aforesaid method, step (f) is carried out by means of an electrochemical sensor. In another aspect of the method, step (f) is carried out amperometrically using an electrode. In a further aspect of the method, step (f) is carried out by spectrophotometry after addition of peroxidase and a colorimetric indicator. In one aspect, the peroxidase is horseradish peroxidase. In a further aspect, the colorimetric indicator is 2,2′-azino-di-(3-ethylbenzthiazoline-6-sulfonic acid). In yet a further aspect of the invention, the colorimetric indicator is 3,3′,5,5′-tetramethyl benzidine. In a further aspect of the invention, the colorimetric indicator is a multicomponent oxidative coupling reagent of Trinder or Ngo-Lenhoff type.
[0049] Moreover, the backing member of the tape is formed of polyester. The medical adhesive is a pressure-sensitive adhesive. In one aspect of the invention, the medical adhesive is an acrylic based adhesive. In another aspect of the invention, the medical adhesive is a synthetic rubber elastomer adhesive. In yet a further aspect of the invention, the medical adhesive is a silicone based adhesive. In a further aspect, the medical adhesive comprises an elastomer formed of block polymers of styrene-isoprene-styrene or styrene-butadiene-styrene.
[0050] The present invention also provides, in a fourth aspect thereof, a kit for use in carrying out a method according to the first aspect. The kit comprises:
the aforesaid tape; the aforesaid source of affinity-enzymatic compound of formula A-C-B, wherein A, B and C are as defined above; and a source of the aforesaid color developing agent.
[0054] The detecting agent in the aforesaid kit is selected from the group consisting of steroid glycosides, triterpene glycosides, hydrophobic proteins, polyene antibiotics and anti-cholesterol antibodies. In one aspect of the invention, the detecting agent is a steroid glycoside, and the steroid glycoside is digitonin.
[0055] Further, in the aforesaid kit, the enzymatic visualizing agent is an enzyme selected from the group consisting of peroxidase, alkaline phosphatase, urease, galactosidase, glucose oxidase and acetylcholinesterase. In one aspect of the invention, the enzyme is peroxidase, and the peroxidase is horseradish peroxidase.
[0056] Moreover, the aforesaid kit further includes an aqueous solution containing hydrogen peroxide, the color developing agent being present in said solution. The color developing agent is selected from the group consisting of 2,2′-azino-di-(3ethylbenzthiazoline-6-sulfonic acid) and 3,3′,5,5′-tetramethyl benzidine. In one aspect of the invention, the color developing agent is 3,3′5,5′-tetramethyl benzidine.
[0057] Further, in the aforesaid kit, the binding agent is a copolymer of maleic anhydride and N-vinylpyrrolidone.
[0058] Moreover, the backing member of the tape is formed of polyester. The medical adhesive is a pressure-sensitive adhesive. In one aspect of the invention, the medical adhesive is an acrylic based adhesive. In another aspect of the invention, the medical adhesive is a synthetic rubber elastomer adhesive. In yet a further aspect of the invention, the medical adhesive is a silicone based adhesive. In a further aspect, the medical adhesive comprises an elastomer formed of block polymers of styrene-isoprene-styrene or styrene-butadiene-styrene.
[0059] The invention further provides, in a fifth aspect thereof, a kit for use in carrying out a method according to the second aspect. The kit comprises:
the aforesaid tape; and the aforesaid source of affinity signal-generating compound of formula A-C-B′, wherein A, B′ and C are as defined above.
[0062] The detecting agent in the aforesaid kit is selected from the group consisting of steroid glycosides, triterpene glycosides, hydrophobic proteins, polyene antibiotics and anti-cholesterol antibodies. In one aspect of the invention, the detecting agent is a steroid glycoside, and the steroid glycoside is digitonin.
[0063] The indicator agent in the aforesaid kit is selected from the group consisting of dyes, fluorophores, radioisotopes, metal sol compounds and chemiluminescent compounds. In one aspect of the inventions, the indicator agent is a dye. In another aspect of the invention, the indicator agent is a fluorophore. In a further aspect of the invention, the indicator agent is a radioisotope. In another aspect of the invention, the indicator agent is a metal-sol compound. In a further aspect of this invention the indicator agent is a chemiluminescent compound.
[0064] In the aforesaid kit the binding agent is a copolymer of maleic anhydride and N-vinylpyrrolidone.
[0065] Moreover, the backing member of the tape is formed of polyester. The medical adhesive is a pressure-sensitive adhesive. In one aspect of the invention, the medical adhesive is an acrylic based adhesive. In another aspect of the invention, the medical adhesive is a synthetic rubber elastomer adhesive. In yet a further aspect of the invention, the medical adhesive is a silicone based adhesive. In a further aspect, the medical adhesive comprises an elastomer formed of block polymers of styrene-isoprene-styrene or styrene-butadiene-styrene.
[0066] The invention additionally provides, in a sixth aspect thereof, a kit for use in carrying out a method according to the third aspect. The kit comprises:
the aforesaid tape; and the aforesaid source of cholesterol oxidase.
[0069] In the aforesaid kit the peroxidase is horseradish peroxidase. In one aspect of the invention, colorimetric indicator is of 2,2′-azino-di-3-ethylbenzthiazoline-6-sulfonic acid). In another aspect of the invention, the colorimetric indicator is 3,3′5,5′-tetramethyl benzidine.
[0070] Moreover, the backing member of the tape is formed of polyester. The medical adhesive is a pressure-sensitive adhesive. In one aspect of the invention, the medical adhesive is an acrylic based adhesive. In another aspect of the invention, the medical adhesive is a synthetic rubber elastomer adhesive. In yet a further aspect of the invention, the medical adhesive is a silicone based adhesive. In a further aspect, the medical adhesive comprises an elastomer formed of block polymers of styrene-isoprene-styrene or styrene-butadiene-styrene.
[0071] Moreover, in all of the aforesaid kits, the tape is carried by a closeable device, the closeable device having a sampling member that carries the tape, and a closure member adapted to engage the sampling member and retain the tape within the device. It is preferable that the tape is sealed within the device when the closure member engages the sampling member. In one aspect, at least the closure member or the sampling member is provided with a peripheral rim, and the other of the closure member or the sampling member is provided with a peripheral groove adapted to receive the rim so that the tape is sealed within the device. The closure member can be connected to the sampling member by a hinge.
[0072] In one aspect of the invention, at least a portion of the sampling member is adapted to be cut from the closeable device to form a dipstick, the dipstick having a first end thereof devoid of tape, and a second end thereof with the tape.
[0073] In a second aspect of the invention, at least a portion of the sampling member is adapted to be cut from the closeable device to form a disk, the disk having the tape provided on one face thereof.
[0074] Further, the aforesaid kits can further comprise a cutting tool adapted to cut the disk from the device. To show where the cutting tool is to be applied the the closeable device can be provided with a marker on an outside surface thereof.
[0075] Moreover, the cutting tool can be provided with a plunger to eject the disk from the end of the cutter after the disk is cut.
[0076] The invention also provides for a tape stripping device for use in obtaining skin samples, the device comprising:
a) a sampling member having a surface, b) a tape provided on at least a portion of the surface of the sampling member, the tape having a medical adhesive presented away from the surface; and c) a closure member adapted to engage the sampling member and retain the tape within the device.
[0080] It is preferable that the tape is sealed within the device when the closure member engages the sampling member. In one aspect, at least the closure member or the sampling member is provided with a peripheral rim, and the other of the closure member or the sampling member is provided with a peripheral groove adapted to receive the rim so that the tape is sealed within the device. The closure member can be connected to the sampling member by a hinge.
[0081] In one aspect of the invention, at least a portion of the sampling member is adapted to be cut from the closeable device to form a dipstick, the dipstick having a first end thereof devoid of tape, and a second end thereof with the tape.
[0082] In a second aspect of the invention, at least a portion of the sampling member is adapted to be cut from the closeable device to form a disk, the disk having the tape provided on one face thereof.
[0083] Applicant has found quite surprisingly that the measurement of skin cholesterol can be carried out directly on the skin sample adhering to the aforementioned tape. The procurement of skin samples removed by tape stripping from donor individuals allows assays to be conducted at distant and centralized sites and also allows assays from many individuals to be run concurrently. Thus, the method according to the invention is suitable for large scale screening of individuals for assessing their risk of cardiovascular disease.
BRIEF DESCRIPTION OF THE DRAWINGS
[0084] For a better understanding of the present invention and to show more clearly how it would be carried into effect, reference will now be made by way of example, to the accompanying drawings that show a preferred embodiment of the present invention, and in which:
[0085] FIG. 1 is a top view of a sampling device as used in Example 2,
[0086] FIG. 2 is a fragmentary view of the sampling device illustrated in FIG. 1 , showing details of the sampling member thereof;
[0087] FIG. 3 is a perspective view of a dipstick cut from the sampling device of this invention;
[0088] FIG. 4 is a perspective view of a disk cut from the sampling device of this invention in an alternative embodiment;
[0089] FIG. 5 is a cross-sectional view of a disk from FIG. 4 in the well of a microwell plate;
[0090] FIG. 6 is a perspective view of the sampling device with cutting tool to produce a disk of FIG. 4 ;
[0091] FIG. 7 is a cross-sectional view of the sampling device with cutting tool to produce a disk of FIG. 4 ; and
[0092] FIG. 8 is a cross-sectional view showing the cutting tool placing the disk in the well of a microwell plate.
DETAILED DESCRIPTION OF THE INVENTION
[0093] Use is preferably made of a tape comprising a backing member formed of polyester. The tape is coated on at least one side thereof with a medical adhesive. The term “medical adhesive” as used herein refers to an adhesive which is hypoallergic and safe for application to the skin. Such an adhesive is preferably a pressure-sensitive adhesive, for example, an adhesive comprising an elastomer formed of block polymers of styrene-isoprene-styrene or styrene-butadiene-styrene.
[0094] As can be appreciated, there are many classifications and types of adhesives. In general, any adhesive suitable for use with this Invention is a medical adhesive as defined above to ensure there will be generally no problems with allergic reactions when the adhesive was applied to the skin for sampling. The inventors tested several types of adhesives for use in taking a skin sample; the majority of these were pressure sensitive acrylic based adhesives, but several synthetic rubber type elastomer adhesives and silicone based adhesives were also tested.
[0095] The inventors have found that synthetic rubber adhesives based on block copolymers of styrene and butadiene or styrene and isoprene perform well for this invention. An example of a synthetic rubber adhesive is a synthetic Kraton™ type adhesive (latex free) based on a block copolymer of styrene and butadiene. Such an adhesive provided better stability for skin samples to facilitate transportation of the samples for subsequent analysis.
[0096] A further preferred adhesive tape for use in the method of the invention is a double-coated pressure-sensitive medical grade tape. Examples of such a medical grade tape are those sold by 3M under Product #9877, or by Adhesive Research, Inc. under Product #8570.
[0097] A list of some of the other tapes that have been tested by the inventors is shown in the accompanying table. The one requirement that is constant is the use of a medical grade tape that is hypoallergenic.
TABLE 1 Adhesive Tape Product Name Supplier MA 27Acrylic AR 8570 Adhesive Research, Inc. MA 38 Acrylic AR 7396 Adhesive Research, Inc. HY-3 Acrylic AR 8311 Adhesive Research, Inc. Urethane liner MA 65 Acrylic AR 8944 Adhesive Research, Inc. MA 61 Acrylic AR 8890 Adhesive Research, Inc. Acrylic AR 8968 Adhesive Research, Inc. AS 124M Acrylic AR 8651 Adhesive Research, Inc. Acrylic MA 38 Adhesive Research, Inc. MA 31 Acrylic MA 31 Adhesive Research, Inc. MA24 MA 24A Adhesive Research, Inc. rosin tackified polyisubutylene Rubber solution MA 70 Adhesive Research, Inc. Acrylic MA 46 Adhesive Research, Inc. Acrylic #888 3M acid free Silicone N/A Alza Corporation Duragesic base Silicone/acrylic 702 Scapa Group PLC Silicone/silicone 705 Scapa Group PLC
[0098] It can be appreciated that the adhesive tapes listed in Table 1 is not meant to be exhaustive, but merely illustrative of different adhesive tapes that are suitable for use with this invention at the present time, and that other adhesive tapes that will be apparent to those skilled in the art are contemplated by this invention.
[0099] Double-coated pressure-sensitive tapes are generally available with an easily removable protective liner. The liner protects the tape from adhering until it is removed and keeps the adhesive from becoming contaminated. Liners may be placed on either side of the double-coated tape or the tape may have a single liner and be wound onto itself, thereby protecting both surfaces.
[0100] Liners with differential release properties may be used so that a first side of adhesive may be exposed while protecting the second adhesive surface. A double-coated tape with differential liners is particularly advantageous for skin sampling. Removal of the first liner allows the tape to be stuck onto the backing support of a sampling device and leaves the skin-sampling side covered with the second liner. This second liner protects the skin sampling adhesive area from sticking and from contamination until it is to be used. When required for skin sampling, the second liner is removed.
[0101] The tape can be applied onto any part of skin, but the most suitable part is the surface of a palm because the palm does not have sebaceous glands whose secretions contain cholesterol which may affect results. Additionally, the skin on the palm is readily accessible for sampling.
[0102] It is desirable to obtain uniform amounts of skin samples for analysis. Application of the adhesive tape for sampling is typically and routinely done using a single application of the tape to the skin. Additional amounts of stratum corneum material can be obtained by additional applications of the tape to the skin. Each subsequent application of the tape to the skin results in additional skin adhering to the tape. This process continues until the tape becomes saturated with skin material after which it is no longer sticky. The number of applications required to saturate a tape depends on the type of adhesive used, but for the most commonly used adhesive tapes, saturation is achieved with less than ten applications, for example, but not limited to, three to seven applications. Applying tape to a fresh area of skin for each subsequent stripping results in better and faster saturation of the tape. Therefore, for consistent and good sampling, it is convenient to make ten applications of a tape to the skin, using new areas of skin for each application.
[0103] The total amount of cholesterol present in the skin sample on the adhesive tape is related to the size of the skin sample obtained. Moreover, a consistent skin sample size is required in order to compare relative levels of skin cholesterol between different individuals.
[0104] Obtaining consistently sized skin samples from various individuals (or repeated samples from the same individual) is accomplished by the following steps. First, as previously described, the skin sample is taken by applying the adhesive tape repeatedly to the skin such that it becomes saturated with skin and is no longer sticky. The tape becomes saturated with skin after about three to seven applications and ten applications are routinely done to ensure saturation. Next, to obtain a constant area of skin sample to be assayed, a fixed sized area (for example, as will be hereinafter become apparent from Examples 2 and 3) from the skin-sampling device is removed, and immersed in standardized volumes of detector and indicator reagents, as will also be described hereinafter.
[0105] After skin sampling, the sampling device is closed and shipped to a central laboratory for assay of cholesterol.
[0106] When using a compound of formula A-C-B or A-C-B′ for the analysis of cholesterol in the skin samples, the detecting agent A can be for example a steroid glycoside, a triterpene glycoside, a hydrophobic protein, a polyene antibiotic or an anti cholesterol antibody. Use is preferably made of a steroid glycoside, such as digitonin. The binding agent C, on the other hand, is preferably a copolymer of maleic anhydride and N-vinylpyrrolidone.
[0107] In the case where use is made of a compound of formula A-C-B, the enzymatic visualizing agent B is preferably an enzyme selected from the group consisting of peroxidase, alkaline phosphatase, urease, galactosidase, glucose oxidase and acetylcholinesterase. Peroxidase such as horseradish peroxidase is preferred. In this particular case, after step (e), the peroxidase is activated with hydrogen peroxide to form an activated peroxidase, and the color developing agent used in step (f) reacts with the activated peroxidase to form the aforesaid colored product. To this end, a predetermined amount of an aqueous solution containing hydrogen peroxide and the color developing agent is applied in step (f) onto the predetermined surface area of the sample. Examples of suitable color developing agents which can be used in step (f) include 2,2′-azino-di-(3-ethylbenzthiazoline-6-sulfonic acid) and 3,3′,5,5′-tetramethyl benzidine. 3,3′5,5′-Tetramethyl benzidine is preferred.
[0108] In the case where use is made of a compound of formula A-C-B′, the indicator agent B′ can be for example a dye, a fluorophore, a radioisotope, a metal sol compound or a chemiluminescent compound. When the indicator agent is a dye, step (f) can be carried out by spectrophotometry, such as colorimetry. When the indicator agent is a fluorophore, step (f) can be carried out by fluorometry. When the indicator agent is a radioisotope, step (f) can be carried out by means of a radioactivity sensor. When the indicator agent is a metal-sol compound, step (f) can be carried out by colorimetry. When the indicator agent is a chemiluminescent compound, step (f) can be carried out by luminometry.
[0109] In the case where use is made of cholesterol oxidase as a detecting agent having affinity for cholesterol, step (f) is preferably carried out by means of an electrochemical sensor, for instance, amperometrically using an electrode. Step (f) can also be carried out by spectrophotometry after addition of peroxidase and a colorimetric indicator. The peroxidase used is preferably horseradish peroxidase. Examples of suitable colorimetric indicators which can be used include 2,2′-azino-di-(3-ethylbenzthiazoline-6-sulfonic acid) and 3,3′,5,5′-tetramethyl benzidine. A colorimetric indicator consisting of a multicomponent oxidative coupling reagent of Trinder or Ngo-Lenhoff type can also be used. When use is made of peroxidase and a colorimetric indicator, the aforementioned kit for carrying out the method according to the third aspect of the invention further comprises a source of peroxidase and a source of the colorimetric indicator.
[0110] The method, according to the invention, achieves a simple, high throughput skin cholesterol assay.
EXAMPLE 1
[0111] A double-coated pressure-sensitive medical grade tape having a protective release liner on an upper sampling side and sold by Adhesive Research, Inc. was used. A piece of tape 1 inch by 1 inch was cut. The piece of tape was stuck, using the exposed, lower adhesive surface to one end of a 1 inch by 3 inch thin plastic (white polystyrene) member, leaving a 1 inch by 2 inch piece of uncovered plastic as a handle for applying the tape to the skin and for labeling the sample.
[0112] To obtain a skin sample, the protective liner was removed and the exposed adhesive area applied to a clean dry section of skin. Pressure was applied to the back of the plastic member over the adhesive area to effect good contact of the adhesive with the skin. The plastic member with the attached tape and stratum corneum sample was then peeled from the skin.
[0113] The sample was cut into four equal pieces each measuring ½ inch by ½ inch. One piece was placed in a well of a 12 well tissue culture plate, or similar container, with the skin sampling side facing up. An aliquot of reagent of the type A-C-B was then applied onto a predetermined surface area of the skin sample. The A-C-B reagent used was a conjugate of digitonin (A) linked to horseradish peroxidase (B) through a maleic anhydride-N-vinylpyrrolidone copolymer (C). The reagent was left in contact with the skin sample for fifteen minutes at room temperature, after which it is removed by aspiration. Thereafter, the sample was washed with three separate aliquots of a wash solution to remove non-specifically bound reagent. The piece was then placed in a new, clean well of a 12 well tissue culture plate, or similar container, with the skin sampling side facing up. An aliquot of substrate solution was applied to the sample and left in contact with the skin sample for about fifteen minutes at room temperature. The substrate solution used was Enhanced K-Blue reagent available from Neogen Corp. (Lexington, Ky., USA) and containing hydrogen peroxide and tetramethyl benzidine as color developing agent. An aliquot of the developed substrate solution was removed from the well and added to an aliquot of 1 N sulfuric acid in a well of a 96 well microwell plate. The optical density of the resulting solution, which is a measure of the amount of cholesterol in the skin sample, was read at about 450 nm on a plate reading spectrophotometer.
EXAMPLE 2
[0114] Use was made of a sampling device as shown in FIG. 1 . The sampling device, which is generally designated by reference numeral 10 , is formed of plastic (polypropylene) and comprises a sampling member 12 connected to a closure member 14 by an integral hinge 16 . The closure member 14 has a peripheral rim 18 and four pins 20 , adapted to lock into, respectively, a peripheral groove 22 and four holes 24 formed in the sampling member 12 . Folding the hinge 16 causes engagement of the rim 18 with the groove 22 and of the pins 20 with the holes 24 , thereby ensuring that the two halves of the device 10 remain closed and sealed to prevent dust and contamination of the interior surfaces. The outer surface (not shown in FIGS. 1 and 2 ) of the closure member 14 has a flat area for receiving a label and barcode strip, for sample identification. The sampling member 12 and closure member 14 are respectively provided with finger-tabs 26 and 28 for opening the device 10 .
[0115] A double-coated pressure-sensitive medical grade tape 30 having a protective Kraft paper release liner 32 and sold by 3M under Product #9877 was adhered to the central area of the sampling member 12 . The release liner 32 is wider than the adhesive tape 30 , thereby defining a strip 32 ′ along one edge with no attached tape. This strip 32 ′ of liner overhangs the edge of the device to form a tab for easy removal of the liner. Immediately before use, the liner 32 is removed using the overhanging tab 32 ′ and this exposes the adhesive of the tape 30 for skin sampling.
[0116] The palmar skin area for sampling was cleaned and dried. The tape 30 with the exposed adhesive was applied onto the palm. The tape 30 was pressed against the skin by applying pressure to the back of the sampling member 12 above the adhesive area, thereby causing adherence of the stratum corneum layer. The device 10 was peeled away, reapplied to a new area of the palm and again pressed to the skin. The device is peeled away and applied to the palmar skin in this way for a total of 10 applications.
[0117] At least two small dipsticks 40 (see FIG. 3 ) about four mm in width were cut from the device 10 after application to the skin as follows. Referring to FIG. 2 , an end portion of the sampling member 12 was removed by cutting along the portion of groove 22 , which is adjacent to the tab 26 . Three cuts were then made along guide lines 36 (shown in FIG. 2 ) molded into the sampling member 12 , to delineate the four mm sticks, cutting from the edge to just past the centre line. The two 4 mm wide sticks were released from the sampling member 12 by making a third cut across the center of the member 12 , using guide line 38 molded into the member 12 . Sticks 40 had a first end portion 42 devoid of tape and a second end portion 44 with tape having the skin sample adhered thereto.
[0118] The sticks were each placed into approximately 100 μL solution of an A-C-B reagent in wells of a 96 well microwell plate (not illustrated). The reagent was a conjugate of digitonin (A) linked to horseradish peroxidase (B) through a maleic anhydride-N-vinylpyrrolidone copolymer (C) and was used at a concentration of approximately 1 μg/mL. The sticks were left in the solution for about fifteen minutes at room temperature, after which they were removed and placed into new wells of a microwell plate containing approximately 200 μL of wash solution. The microwell plate was agitated to effect washing and after about one minute the sticks were removed to new wells containing approximately 200 μL of fresh wash solution and again agitated for about one minute. Washing with agitation was done a third time, after which the sticks were removed and placed in approximately 100 μL of a substrate solution (Enhanced K-Blue reagent). The sticks were then incubated with the substrate solution, in the dark, for about fifteen minutes at room temperature. The microwell plate can be shaken during this step.
[0119] After the sticks were incubated, the sticks can then be removed. Approximately one hundred (100) μL of 1 N sulfuric acid is then added to the wells with the substrate solution to stop further reaction, and the optical density of the resulting solution was read at about 450 nm on a plate reading spectrophotometer, to provide a measure of the amount of cholesterol in the skin sample.
EXAMPLE 3
[0120] To allow many samples from Example 2 to be processed together requires that the dipsticks 40 be held in a configuration that matches that of a standard 96 well (8×12) microplate. Instruments are available that can dispense reagents into these plates and also to wash the wells, a requirement that is necessary to prevent reagent carry-over between assay steps. Spectrophotometers that can read the coloured solutions directly in the wells at the final step of the assay are also readily available. However, for such an application, the protruding part of the dipsticks from the wells, and the fixtures that hold them, prevent easy access to the wells for dispensing and washing steps. This results in a dipstick assay that requires customized equipment and/or more manual steps than conventional assays run in microwells.
[0121] Batch processing of many samples can be achieved by removing small disks 50 (see FIG. 4 ) having skin samples 70 adhered to the adhesive tape 30 from the sampling device on one face 52 thereof (skin sample 70 and adhesive 30 are generally illustrated in the Figures as adhesive 30 for purposes of clarity, however, it is to be understood that the adhesive 30 will have skin 70 thereon after application of the device to, for example, the palm of a person), and then processing these disks in the wells 54 of a microplate 56 , as shown in FIG. 5 In this manner there are no protrusions above the well and so readily available automated liquid dispensing and washing equipment can be used to add reagents required for cholesterol assay. The disks are sized to fit into the wells of a microplate, yet remain free and not become wedged or trapped within the well. For example, but not limited to, disks that are smaller than 6.0 mm diameter will fit into the wells of all commonly manufactured microplates. It can be appreciated, however, that disks that are too small will have insufficient amount of skin that will compromise assay sensitivity and reproducibility. It has been found that disks 5 to 6 mm in diameter are best suited for assay in 96 well microplates. However, it can be appreciated that the invention is not limited to these dimensions, and that other disk sizes are contemplated for different wells and microplates, as would be apparent to those skilled in the art.
[0122] In addition, when the disks are placed in the well, they should not float with the skin-side up since this will contact the dispensing and aspiration tubes that are inserted in the wash steps. Therefore, if the sampling device is constructed of materials that are less dense than water the disks should be added to the well with the skin side down. If the sampling device is constructed of materials that are more dense than water, then the disk is best added with the skin side up and the height of the dispensing and aspiration tubes adjusted so that they do not touch the skin surface.
[0123] Either a customized cutting tool or a single-hole paper punch sized 3/16 in. (4.76 mm) can be used to remove disks from the sampling device. The disks must be cut from the device such that any anvil-type part used to eject the disk from a punch or cutting tool must not contact the skin. Thus, when using a paper punch the anvil should contact the back of the device (non-skin side) when cutting and ejecting a disk.
[0124] Referring to FIGS. 6 and 7 , a cutting tool 60 removes a disk from the device 10 of FIG. 1 when the device 10 is in a folded over (closed) position, as illustrated. The closed device is placed on a firm surface (not illustrated) with the outer surface 62 of the sampling member 12 of the device facing up. The cutting tool 60 is inserted in a circular depression 64 that can be provided on the outer surface 62 of the sampling member 12 of device 10 and the cutting tool 60 is then pressed down to cut through the plastic and the tape 30 /skin 70 sample. The cutting tool 60 is not pressed down so far, however, so as to cut through the plastic of the closure member 14 of the device 10 .
[0125] Once a required disk 50 has been cut from the device 10 , the end 66 of the cutting tool 60 with the disk 50 is placed into a designated well 54 of the microwell plate 56 (see FIG. 8 ) and plunger 68 of the cutting tool 60 is depressed to eject the disk with the skin sample on the adhesive tape into the well 54 .
[0126] When all the designated wells of the microwell plate are provided with a disk, the microwell plate is placed on automated plate reader/washer and approximately 100 μL of detector reagent is added to all the wells and the disks are incubated for approximately fifteen minutes at generally room temperature (20-24° C.). The reagent can be a solution of an A-C-B reagent as defined in Example 2.
[0127] The detector reagent is then aspirated and approximately 250 μL of wash buffer is added to the wells. The plate can be shaken for approximately thirty seconds after the addition of the wash buffer, removing excess detector reagent, and then left for approximately a further ninety seconds. The wash step can be repeated two or more times as necessary. It is found that three wash steps are satisfactory.
[0128] After the wells are washed, approximately 100 μL of Enhanced K-Blue substrate is added to the wells and allowed to incubate with the washed disk for approximately fifteen minutes at generally ambient room temperature (as previously described). The microwell plate can be shaken during this step, and, as in Example 2, the incubation can be in the dark.
[0129] The reaction is then stopped by the addition of approximately 100 μL of 1 N sulphuric acid to the wells, and the plate is shaken to mix the solutions. Approximately 100 μL of the stopped substrate is then removed and transferred to the wells of a new plate and read at about 450 nm on a plate reading spectrophotometer and analyzed as previously described to determine the relative level of skin cholesterol for each donor.
[0130] In the above examples, it can be appreciated the invention is not intended to be limited to the exact values specified in the Examples and that variations from the volumes, times, temperatures, and wavelengths stated can be made by those skilled in the art without affecting the scope of the invention, hence the use of the terms “approximately” and “about.”
[0131] The following description is meant to be illustrative only and not limiting. Other embodiments of this invention will be apparent to those of ordinary skill in the art in view of this description.
[0132] While the embodiments of the invention disclosed are presently considered to be preferred, various changes and modifications can be made without departing from the scope of the invention. The 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. All these alternatives and variations are intended to be included within the scope of the claims. Those familiar with the art may recognize other equivalents to the specific embodiments described that are also intended to be encompassed by the claims.
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Skin cholesterol is measured by applying an adhesive tape onto a selected area of the skin to adhere the tape to the selected skin area and stripping the tape off the selected skin area to obtain a sample representative of the outer stratum corneum layer of the skin, the sample adhering to the tape so as to have exposed skin constituents. The sample is assayed using a detector reagent that specifically binds to cholesterol and in addition has an indicator component that allows quantitation of the amount of cholesterol present in the exposed skin constituents.
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CROSS REFERENCE TO RELATED APPLICATIONS
This application is a United States National Phase application of International Application PCT/EP2007/009616 and claims the benefit of priority under 35 U.S.C. §119 of German Patent Application DE 20 2006 016 981.4 filed Nov. 7, 2006, the entire contents of which are incorporated herein by reference.
FIELD OF THE INVENTION
The present invention relates to a combination device for performing different tasks such as snow throwing, mowing, scarifying, soil breaking, sweeping or the like by means of interchanging the work implements such that each implement is adapted for each respective task, whereby a machine frame is intended for taking on the respective work implement and letting it be driven in rotation, and that the respectively installed work implement is enclosed by a partially open cylindrical housing the rotational axis of which lies in parallel to that of the work implement.
BACKGROUND OF THE INVENTION
Combination devices of such nature have been known in various guises in the past:
DE 2 017 981 A discloses one such combination snow thrower consisting of a basic machine. On such machine, various work implements can be interchanged by pulling out the axle pin. Work implements in cylindrical form can be used for tasks like salt sprinkling, snow clearing, ice and earth breaking, as well as lawn mowing and sweeping. Such cylindrical work implements can be rotated about an axis horizontal and parallel to the ground by means of a motor on board the machine.
In order to throw snow, a cylindrically shaped snow throwing drum with transverse shoveling paddles as described in DE 2 017 981 A is used. Ice breaking is another feature of the device which can be realized by replacing the snow throwing drum with a steel spiky one. For sweeping of powdery snow, garden debris or the like, a sweeping drum can be deployed with steel or plastic bristles. For soil breaking, a tilling drum is used, whereby it is combined with paddle wheels that are covered and together with which the dug up soil will be blown to the side. For lawn mowing, a cutting reel is used whereby the grass clippings are blown forward by the paddle wheels (fan) into a container. The cutting reel takes the form of two cutting knives with two sweeping brushes located at the back and which are intended for sweeping grass cuttings into the fan.
Another feature of the device in DE 2 017 981 A has a spreader that can be additionally attached to it for the purpose of sprinkling salt as well as soil fertilizer. Such combination device is penalized by the fact that not all its functionalities can be optimally designed for all the work tasks. In particular, in the case of snow throwing, a discharge chute is not provided for displacing snow at a further distance away during or at the end of the snow cutting process.
DE 31 00 904 C2 refers to another embodiment of a motorized walk-behind machine for snow clearing, sweeping or scarifying. This machine shows a basic housing into which various work implements, as described already in DE 2 017 981 A, can be accommodated.
According to DE 31 00 904 C2, additional side wheels can be mounted onto the housing such that the machine can be used as a scarifier. The side wheels however have to be mounted separately. Another disadvantage lies in the drive axis which, depending on the functionality, is supported from one side only, thereby leading to instability. In order to utilize the device as a sweeping machine or a snow thrower, the fixed housing and machine together are rotated about the work implement axis, thereby being brought into two distinctly different inclinations relative to ground. Furthermore, the device may for example be hampered by its inability to allow for height adjustment or the separation between the work implement and ground. The device is generally penalized in terms of its handling.
DE 38 12 105 C2 proposes a combination device for garden and roads. The embodiment includes a housing that is forwardly half open and which caters for different work implements. The work implements in turn are housed within their own casings both of which can be mounted and fixed onto the main device housing. Work implements for lawn mowing, scarifying, throwing snow, sweeping and blowing have also been mentioned.
According to DE 38 12 105 C2 and the claims therein, the work implements with their respective housings can be shifted sideways and subsequently locked into position within the device housing. In operation, the axis of the work implement is mechanically coupled to the device's own actuator by means of a pinion. The device is extremely troublesome to set up and requires individual housing for each work implement to be attached onto the main device housing.
The combination device as referred to in U.S. Pat. No. 4,064,679 A shows yet another embodiment that can be adapted for lawn mowing, snow throwing and lawn sweeping. Due to the inter-changeability of individual work implements, the device is also capable of multiple tasking. However, the changing of work implements is complicated by the housing, whose side wall has to be physically dismounted first, by undoing a number of bolts, before finally being able to change over the work implements. Additional housing covers or housing attachments are included for the different functionalities, which further complicate the tool setup not to mention the provision for additional storage of individual parts.
SUMMARY OF THE INVENTION
The deficiency just described is overcome in accordance with the present invention wherein the changing of different work implements is simplified and functionally optimized.
The work task is fulfilled by a combination including inter-changeable work implements which adapt to the tasks in the respective operating configurations, a base frame onto which the respective work implements can be mounted and driven in rotation and whereby the individually built in work implement is partially enclosed by a housing that runs parallel to the rotation axis of the work implement. The housing is rotatable about an axis parallel to the drive axis of and can be locked into its respective position depending on the work task at hand.
Tool changing is hence made much easier through the rotatable housing of the combination device. Furthermore, tool changing is facilitated by having the housing only partially enveloping the work implement thereby permitting the necessary access. On the other hand, the housing can be brought to different positions, such that individual work tasks are optimally performed within the necessary work implement enclosure.
In the preferred embodiment, the housing encloses the work implement over a wrap angle such that the housing opens itself relatively forward and downward in the first operating position, mostly downward in the second operating position, and relatively backward and downward in the third operating position. Through such arrangement, snow throwing for example can be optimally performed when the housing is fixed with its opening facing the front and pointing downward. Lawn mowing for example can equally and optimally be performed by having the housing face downward and backward.
According to other features, the housing is equipped with rollers, wheels or rolling cylinders along its front and back edges that run parallel to the axis of work implement's rotation in such a way that the housing is supported off the ground by its back set of rollers, wheels or rolling cylinder when in the first operating position, the housing is not supported by any rollers, wheels or rolling cylinder when in the second operating position, the housing is supported off the ground by its front set of rollers, wheels or rolling cylinder when in the third operating position.
In the case of snow throwing, instead of rollers, wheels or rolling cylinder, the housing can also be supported by conventional skids which is height adjustable. The possibility for height adjustment also applies to the rollers, wheels or rolling cylinder.
The housing may be fitted with a scraper bar along its back edge in order to take up snow while the device is being used as a snow blower, and that the housing exhibits an opening in its first operating position on top of which a discharge chute can be attached. Through this configuration, the housing is best optimized for snow throwing. Through the rollers, wheels or rolling cylinder, the height of the scraper bar can be adjusted relative to ground in such a way that the combination device can best adapt to the respective working conditions.
The housing comprises two side walls that can be mounted in relative rotation to the two side plates of the basic frame, and that in the first side plate, provision is made for the transmission axle, and that in the second side plate, an axle journal is available, such that the inter-changeability and the rotation of different work implements and their adjustability can be catered for. Through this configuration, the work implements can be changed over easily and secured within a cost-effectively and simply designed housing.
The transmission axle is belt driven and that the respective work implements are coupled in rotation to and detachable from the transmission axle. Such form of transmission is especially easy to maintain.
The base frame may form an integral part of the basic machine, and the basic machine exhibits means of transport in the form of wheels, with which the basic machine together with the base frame and the respective work implement can be driven on the ground. The basic machine may have wheels which are height adjustable. The wheels can be free running such that the combination device can simply be pushed along by hand. To lighten the work load, the same wheels can be motorized and whose coupling can be switched on or off.
A motor actuator may be provided to drive the work implements via a pulley belt or the like. This motor actuator can also be used for driving the wheels via a switchable gear set.
The configuration of the different interchangeable work implements, especially in relation to snow throwing, mowing, scarifying, soil breaking or sweeping are also described. It is to be understood that the invention is not limited in its application to the details of construction and the arrangement of components as set forth.
As far as a self-contained walk-behind combination device is concerned, the wheels can also be driven by the on board motor actuator, as in the examples of snow throwing or lawn mowing, and the actuator in turn can also be switched on or off at will.
The combination device can also be so configured that it can be built onto a communal care vehicle, a tractor or the like in the form of an attachment. Here also, it can be seen that the rotatable housing will facilitate the changing over of work implements as well as its optimal operation.
All the work implements have in common a cylindrical form and that their axis of rotation is relatively parallel to the ground being worked on and runs across the direction of machine travel.
The invention in its preferred embodiment will now be described and become more readily apparent on examination of the following description, including the appended drawings. 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 perspective view of the invention, namely the combination device with a rotatable housing excluding the work implement;
FIG. 2 is a front view II of the combination device housing as referred to in FIG. 1 ;
FIG. 3 is a cross-sectional view through the bearing fixture of the drive axis within the housing as referred to in FIG. 2 ;
FIG. 4 is a perspective view of the combination device as referred to in FIG. 1 ;
FIG. 5 is a perspective view of one work implement in the form of an augur for use with the combination device as a snow thrower;
FIG. 6 a perspective view of the combination device as referred to in FIG. 1 with the augur as referred to in FIG. 5 as well as a discharge chute as mounted onto the housing;
FIG. 7 a partial view VII of the snow thrower as implemented from the combination device in FIG. 6 ;
FIG. 8 is a perspective view of one work implement in the form of a mowing reel with the so called upper blades equally spaced along its circumference;
FIG. 9 is a perspective view of a so-called bed-knife which can be combined with the mowing reel in FIG. 8 of the combination device to become a lawn mower;
FIG. 10 is a perspective view of the combination device showing the housing with the attached mowing reel as well as the bed-knife;
FIG. 11 a partial side view XI of the combination device as referred to in FIG. 10 ;
FIG. 12 is a perspective view of a work implement in the form of a scarifying cylinder with spring tines radiating substantially outwards;
FIG. 13 a partial side view of the combination device with the attachment of the scarifying cylinder as referred to in FIG. 12 ;
FIG. 14 is a perspective view of a work implement in the form of a tilling cylinder in perspective view; and
FIG. 15 is a partial side view of the combination device with the attachment of the tilling cylinder as referred to in FIG. 14 .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
Referring to the drawings in particular, FIG. 1 shows the principal configuration of a combination device 1 in its perspective view.
To the rear of the combination device 1 , a wheel frame 2 is shown and which comprises two bent guide rods 3 and 4 , whose upper ends transform into the respective hand grips 5 and 6 . At the lower end of the guide rods 3 and 4 , two wheels 7 and 8 are mounted by means of fixture 9 which enables height adjustment along the guide rods 3 and 4 .
Furthermore, the combination device exhibits a base frame 10 , whose front end is mounted with two vertical side plates 11 and 12 . The side plates 11 and 12 are fixed onto but detachable from the base frame 10 . The base frame 10 is bolted together with the lower parts of the guide rods 3 and 4 by means of the palm grip 13 .
In order to support and strengthen the combination device 1 , a stiffening bracket 14 is seen in the present embodiment with one end being attached to the guide rods 3 and 4 by means of the palm grip 15 , while the other end being attached onto the base frame 10 by means of fixtures 16 . Furthermore, a motor engine 17 can be seen in the present embodiment mounted onto the base frame 10 , and whose very outer end is mounted with a belt pulley 18 .
The belt pulley 18 is connected to another belt pulley 19 via a pulley belt 20 . This pulley 19 serves the purpose of driving the transmission axle 21 , the detailed function of which will be described later.
Lying coaxially to the transmission axle 21 , a gudgeoning pin 22 is seen to the right side of the “rear” side plate 12 , and which forms a straight line with the transmission axle 21 . This gudgeoning pin 22 as well as the transmission axle 21 can be axially and outwardly retracted in order to allow for the easy changing over of work implements.
It is worth noting here that the basic design of the combination device 1 is capable of other embodiments. Important being the two side plates 11 and 12 with a housing 23 sitting in between. The housing 23 can be swung or pivoted about the transmission axle 21 as well as the journal 22 on both side plates 11 and 12 , which is shown in the first operating position in FIG. 1 . In the same operating position, it can be seen that the housing 23 is bolted down by means of two security bolts 24 one of which can be seen in FIG. 1 .
It can also be seen in FIG. 1 that the housing 23 is shown with two side walls 25 and 26 that enable the housing to be mounted about a rotational axis parallel to the transmission axle 21 and to the gudgeoning pin 22 .
Further details on the housing 23 will be explained later with reference to FIG. 4 .
FIG. 2 shows the front view II, in particular, that of the housing 23 as in FIG. 1 . It is noticeable that the housing 23 with its side walls 25 and 26 is fitted in between the two side plates 11 and 12 . These assembly side plates 11 and 12 have on their inner sides clamp rings 27 and 28 that couple the housing 23 with its side walls 25 and 26 and enable them to rotate. The second security bolt 24 can also be seen in FIG. 2 .
It can be further seen that the gudgeoning pin 22 projects into the housing 23 . The transmission axle 21 also displays a drive element 29 that partially projects into the housing 23 . The drive element 29 shows two diametrically opposite and radial projecting drive keys 30 and 31 , via which the transmission axle 21 can be rotationally coupled onto the respective work implement within the housing 23 .
FIG. 3 shows an enlarged view of the transmission axle 21 in the area of the assembly side plate 11 . It can be seen that the drive pulley 19 is rotationally mounted with bearings 32 and 33 along the axle on either of its extreme end. The bearing 33 is seated respectively on the assembly side plate 11 . A support plate 34 outside at a distance away from and fixed onto the assembly plate 11 is as shown in FIG. 1 . The drive pulley 19 is drilled with a hole 35 in the center the inner side of which is cut with two diametrically opposite key slots 36 and 37 . In this key slot, the two drive keys 30 and 31 of the transmission axle 21 can be form fittingly taken up and remain axially adjustable. From the engaging position as shown in FIG. 3 , the transmission axle can be seen axially adjustable in the direction as indicated by the arrow 39 by means such as spring actuation (not shown here) and alike, to such extent that a work implement can be inserted in between the side walls 25 and 26 of the housing 23 .
The fixation for the gudgeoning pin 22 is also designed in a similar fashion. In FIG. 3 , the tooth belt 20 can also be seen.
As already mentioned previously, FIG. 4 shows the housing 23 in perspective view. This view of the housing 23 is already presented as the first operating configuration in FIG. 1 . The housing 23 comprises a partially open cylindrical outer wall 40 , which is fitted or for example welded with the side walls 25 and 26 . To the front of the outer wall 40 , there is a reinforcement fixture 41 formed on top and the front end within which is seen with a bearing shaft 42 . The bearing shaft projects out of the two side walls 25 and 26 such that on either side the wheels 43 and 44 are supported accordingly.
To the back and at the bottom of the outer wall 26 , a lug plate 45 / 1 is shown here together with a second lug plate not displayed in the drawing, the purpose of which is to provide support for the back wheels 45 .
Furthermore, it can be seen in FIG. 4 that in the rear edge 46 / 1 location of the housing 23 , a scraper 46 is provided whose function corresponds to that of a snow thrower.
On the top of the outer wall 40 , an opening 47 can be further seen in the vicinity of which a chute adapter 48 is fitted. The chute adapter 48 serves as a removable mounting platform for the blowing chute 49 , as shown in FIG. 6 that can be typically found in the state-of-the-art snow thrower.
On both the side walls 25 and 26 , locking fixtures 50 and 51 can be seen projecting radially with the purpose of fixing the housing 23 in between the assembly side plates 11 and 12 in the respective operating configuration. In the corresponding configuration, fixation holes 52 can also be seen on the assembly side plate 11 and 12 , as shown in FIG. 6 . The second fixation hole in the lower region of the side wall 11 is seen here hidden by the security bolt 24 , which projects and typically locks through the lower fixture hole 50 on the side wall 25 of the housing 23 . The fixing of the security bolts 24 can be realized by means of bolt nuts 53 and 54 welded onto the locking holes 50 and 51 .
It can be seen further in FIG. 4 that both side walls 25 and 26 have round apertures 55 and 56 , upon which the respective assembly side plates 11 and 12 can be rotationally located, as shown in FIG. 2 .
For the combination device 1 to perform as a snow thrower, as shown in FIGS. 1 and 6 , a snow augur 60 is shown in FIG. 5 , the front portion of which a coupling element 61 can be seen via which the transmission axle 21 with its key elements 30 and 31 can be coupled in firm rotation. On the other end of the rotational axle 62 , opposite to the coupling element 61 , an insertion hole can be found but which is not shown here in FIG. 5 . Further description on the snow augur 60 is deemed unnecessary as it conforms to the state-of-the-art.
FIG. 6 shows the combination device 1 in its snow throwing configuration. It can be recognized that the housing 23 circumscribes the snow augur 60 partially, hence exposing the housing 23 forward in the travelling direction as indicated by the arrow 63 as well as backwards. The wheels 43 and 44 as described in FIG. 4 are functionally redundant in this operating state of the housing 23 . On the contrary, the wheels 45 , the configuration of which corresponds to those of the wheels 43 and 44 , are mounted onto the housing 23 in order to support the combination device 1 on its front end. This can be seen in particular from the side view as shown in FIG. 7 .
It is noticeable that the wheels 45 are being supported by the ground 64 , hence defining through the same wheels 45 the vertical separation between the scraper 46 and the ground. By adjusting the height via the wheels 7 and 8 as shown in FIG. 6 , a pivotal movement will be resulted in the direction as shown by the double arrow 65 ( FIG. 7 ) with the whole combination device 1 pivoting about the rotating axis of wheels 45 , thereby enabling the vertical separation between the scraper 46 and the ground 64 to become adjustable. In this respect, the snow throwing function can be optimally adapted by means of special features such as those located on the housing 23 together with the wheels 45 . It can be seen further in FIG. 7 that the first operating configuration is fixed by means of the security bolt 24 .
Apart from height adjustment via the wheels 7 and 8 , other means of setting the separation between the scraper 46 and the ground 64 is also possible and easily achievable within certain limitation.
FIG. 8 shows a mowing reel 70 , as is generally regarded as state-of-the-art. The mowing reel 70 , as shown in FIG. 8 , comprises a multiple of so-called upper blades 71 which act together with the so-called lower blade 72 , as shown in FIG. 9 , to perform the grass cutting function. It can also be seen in FIG. 8 at the right hand side of the reel cylinder that the coupling journal 73 is equipped with two radially projecting take up slots 74 and 75 . With the slots 74 and 75 , the mowing reel 70 can be attached to the transmission axle 21 in firm rotation via the drive element 29 as well as the two radially projecting key elements 30 and 31 ( FIG. 2 ). On the opposite end of the mowing reel spindle 70 , a fixation hole 76 is located, into which the gudgeoning pin 22 of the assembly side plate 12 in FIG. 2 can be inserted.
The lower blade 72 has two side mounted bolts 77 and 78 , with which the lower blade 72 can be mounted to the assembly side plates 11 and 12 , as shown in FIG. 10 out of the bottom view of the combination device 1 . The lower blade 72 can be adjusted in relation to the upper blades by means of two side adjustment screws 79 and 80 , such that mowing can be adapted to various cut quality. It is also possible to have the mowing spindle 70 together with the lower blade combined into one module which can then be inserted into the housing 23 of the combination device 1 .
Referring to FIG. 10 and FIG. 11 , the housing 23 is now set in its third operating configuration as that of a lawn mower. In this third configuration, both wheels 45 as shown in FIG. 10 are rendered functionally redundant. On the other hand, both the other wheels 43 and 44 are now in contact with the ground 64 , such that the “frontal piece” of the whole combination device 1 is supported by the wheels 43 and 44 . This results in a vertical separation as can be seen in FIG. 11 , between the group of blades, comprising the upper blades 71 and the lower blade 72 , and the ground 64 .
In the third operating configuration, the housing 23 is firmly bolted down by means of the security bolts 24 . The height adjustment is also made possible here via the wheels 7 and 8 that are attached onto the frame pillars 3 and 4 , thereby producing a pivotal effect on the combination device 1 about the rotation axis of the wheels 43 and 44 , the direction of which is as indicated by the double arrow 65 . In this way, a height adjustment is also catered for in the mowing function by setting the distance between the blades, both upper blades 71 and lower blade 72 , and the ground 64 , so as to achieve the required cutting height.
In this configuration of the combination device 1 , the snow throwing chute 49 in FIG. 6 is without saying no longer needed and will be dismantled accordingly. The opening 47 as shown in FIG. 10 which functions as the snow throwing chute adapter 48 as shown in FIG. 11 is preferably to be covered up by means of say a protection cover which is not shown here in the drawing.
Referring to FIG. 10 , a basket for grass collection, which is not shown here, can be placed behind the housing 23 . The basket can also serve as a protection device for the user who drives behind the combination device 1 . Such a basket can also be adapted for the scarifying, tilling or sweeping functions.
FIGS. 12 and 13 show another function of the combination device 1 , whereby FIG. 12 shows the work implement in the form of a scarifying cylinder 85 . This scarifying cylinder 85 comprises a multitude of spring tines 86 that radiate out of the rotational axis and serve as means of aerating the soil in the lawn. The scarifying cylinder 85 in the presented form or in form equipped with radial airing blades is state-of-the-art and whose examples are plentiful.
In FIG. 12 , the scarifying tool 85 is shown with an adapter at its end and two radial slots 88 and 89 , with which the scarifying tool 85 can be coupled in firm rotation to the drive element 29 of the transmission axle 21 via the two drive keys 30 and 31 (see FIG. 2 ).
FIG. 13 shows the configuration of the combination device 1 as scarifier. It can be noticed that the housing 23 is set up in the same third operating configuration as when the combination device 1 is used as mower, as shown particularly in FIG. 11 . Accordingly the operating configuration is fixed in position by means of the security bolts 24 , whereby the wheels 45 are also made redundant here. The housing 23 is supported off the ground 64 by the wheels 43 and 44 in such a way that the penetrating depth of the spring tines 86 can be adjustably defined. Through the height adjustment of wheels 7 and 8 at both the frame pillars 3 and 4 ( FIG. 1 ), the whole combination device 1 can thus be seen pivoting about the bearing axis of the wheels 43 and 44 in direction as indicated by the double arrow 65 such that the penetrating depth of the spring tines 86 can also be adjusted.
The combination device can be easily set up to function as scarifier. The housing 23 is there, as can clearly be recognized in FIG. 13 , opening itself up from beneath and towards the rear against the direction of travel as indicated by the arrow 23 .
In yet another implement, the combination device 1 can be used as a tiller. To this, a work implement typically in the form of a tilling cylinder 95 can be seen in FIG. 14 . The tilling cylinder 95 , as is general known as the state-of-the-art, comprises the so-called cleavers which are used for ground breaking and soil loosening.
FIG. 15 shows part of the side view of the combination device 1 , onto which the tilling cylinder 95 with its cleavers 96 is mounted. It can be seen that under this condition, the runners 45 as well as the runners 43 are made functionally redundant. This means that the housing 23 is fixed in its second operating configuration, and in this case bolted down to the assembly side plates 11 and 12 by the security bolts 24 . On account of this arrangement, the cleavers 96 project well beneath the housing 23 such that a reasonable soil depth penetration can be achieved here. By controlling the handgrips 5 and 6 of the combination device 1 , an optimal soil loosening is made possible.
Instead of the exemplary work implements presented here so far, other cylindrical work implements such as a sweep roller can also be deployed. Through the respective turning of the housing 23 , such a sweep roller in the desired form can be hidden either towards the rear or partially towards the front, so that the combination device 1 can easily be converted into a sweeping machine. If the sweep roller is hidden by the housing 23 towards the front, then a sweep collector can be placed towards the rear for catching all the swept material. In this embodiment, the reversal of the direction of rotation will not be necessary as far as the sweeping function of the combination device 1 is concerned.
In particular, with regards to the height adjustment for the respective work implements or their distance of separation relative to ground, the first and second configurations provide simple means of adjustment, such that the sweeping function and its effectiveness can also be height adapted by means of adjusting the wheels 7 and 8 . Also in this configuration, provision for a sweep collector is possible such that the direction of rotation will not need to be reversed and that extra protection to the user being hit by the swept material can also be provided. It is also possible to have a sweeper rolling against the direction of travel such that the ground material is always swept to the front. In this case, a sweep collector will not be necessary. In the case of such reverse transmission, the housing 23 is best recommended to adopt the snow throwing configuration i.e. facing front and open at the bottom as in the first operating configuration.
It can also be noticed that in particular through the turning of the housing 23 , every function of the combination device 1 can be optimally adapted to the corresponding task in question. The changing of work implements is enormously simplified through the special design of the transmission axle 21 on the one hand, and the gudgeoning pin 22 on the other, such that by their being pulled out, the tool implements can be inserted into the combination device 1 or the housing 23 . Tool changing takes place when the housing 23 is in its first operating configuration, as shown typically in FIG. 1 .
Also it can be imagined that the front part of the combination device 1 with its assembly side plates 11 and 12 as well as the housing 23 can be used as a tool attachment for say a communal service vehicle. The simple retooling and the optimal setting up through the rotatable housing can also be advantageous.
While specific embodiments of the invention have been 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.
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A combination device ( 1 ) is provided for carrying out various work tasks, such as cutting snow, mowing, scarifying, soil breaking or the like. The device includes a plurality of interchangeable work implements ( 60 ) tailored to the respective work task. A basic frame is provided in which the respective work implement ( 60 ) is accommodated and can be driven to rotate, and wherein the respectively installed work implement ( 60 ) is partially enclosed by a housing ( 23 ) extending parallel to the axis of rotation of the work implement. In order to tailor the combination device optimally to the respective work task, provision is made for the housing ( 23 ) to be able to rotate about an axis parallel to the axis of rotation of the respective work implement ( 60 ) and to be fastened in various operating positions corresponding to the respective work task.
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FIELD OF THE INVENTION
[0001] This invention relates to the preparation of ordered organic molecular layers both on flexible and rigid substrates. In particular the invention relates to methods for the preparation of thin light polarization films of lyotropic liquid crystal, which can be used, for example, as the internal polarizers, as well as dichroic polarizers, for the production of liquid crystal displays (LCDs).
BACKGROUND OF THE INVENTION
[0002] Light-polarization films or polarizers are major components of liquid crystal displays (LCDs) and other liquid crystal (LC) devices. Common polarizers are based on polyvinyl-alcohol-iodine (PVA) films of 30-50 μm thickness. These polarizers are generally placed on the external glass surfaces of the LC cell and require protective films (e.g. cellulose triacetate or cellulose acetate butyrate). Their fabrication is rather complicated and expensive. The external placement of the polarizers results in additional reflections and parallax effect, which deteriorates the LCD contrast, optical performance and viewing angles. Consequently, thin internal polarizers for LCDs are highly desirable. However, this variant still cannot be realized on the basis of conventional PVA films.
PRIOR ART
[0003] FR 2,186,165 discloses a method of forming internal polarizers by coating a long linear polymer film (e.g. PVA) to the internal surfaces of the glass substrates. The polymeric solution is then subjected to a linearly mechanical deformation (e.g. using a rubber rod), giving rise to a preferential direction parallel to the substrate plane. This results in an ordering of the long polymeric molecules along the direction of the deformation. Subsequently, the ordered molecular state can be fixed after the evaporation of the solvent. The final polarization film is obtained by a volume impregnation of iodine vapor or iodine solution or a deposition of a dichroic dye. This method is complicated, unreliable and inefficient for LCD manufacturing processes. One of the disadvantages of the method is the diffusion of the iodine molecules into the bulk of the LC. Thus, it leads to the deteriorated resistivity, increased power consumption and diminished life time of the LCD.
[0004] Lyotropic liquid crystals (LLCs) can also be used for the purpose of the preparation of thin polarization films. The LLCs in an organic solvent can be coated on the glass substrate by a mechanical shear flow. After the evaporation of the solvent, the molecular order is maintained in LLC solid film.
[0005] Another method is described in U.S. Pat. Nos. 2,524,286 and 5,739,296 (FIG. 1). The isotropic solution of the lyotropic dye 5 is deposited from the tank 3 onto the anisotropic surface 1 of the flexible polymer film 2 . So a thin film 4 of the dye solution can be formed. Low-cost polyethyleneterephthalate (PET) film can be used as the polymer film 2 . The other variants include the deposition onto the thin layer (0.1-0.5 μm) of paraffin wax, mineral oil, barium stearate, a resin or other materials. Afterwards, the dye layer is oriented by rubbing or brushing to form the anisotropic film 4 . The organic solvent can be composed of water dissolved with low molecular weight solvents, such as acetone, alcohol, dioxane etc. First the ordered nematic LLC phase is formed in the film 7 after the partial evaporation of the solvent 8 . The final evaporation of the solvent 9 , when baking the film 7 , results in a highly ordered solid film of the lyotropic dye 11 with good extinction ratio. The typical thickness of LLC polarizers is 0.3-0.5 μm, which is comparable with the thickness of usual LC alignment layers. The thickness can be regulated by the gap 14 between the die 15 and the surface 1 of the substrate 2 .
[0006] The rate of the evaporation is an important factor. Rapid evaporation at a high temperature results in a “boiling” of the solution, while a slow evaporation rate at a low temperature leads to the formation of randomly oriented dye polycrystals, thus affecting the optical quality of the light polarization films.
[0007] An adhesive layer is used for the transfer of the polarization film from the flexible polymer carrier to the glass substrate of an LCD cell. The adhesive may be pressure sensitive or other permanently tacky type which is rendered tacky by the application of water or other solvent, by heat or other means. For the tacky type adhesives, chlorinated latex, poly-isobutylene of low molecular weight etc. may be used.
[0008] Light polarization films of a large size can be formed, as can leaves of a medium size and special forms, which can be cut from the plane leaves. A volume form is also possible, if convex or concave substrates are applied e.g. for lenses, lamp bulbs etc.
[0009] This technology makes it possible to fabricate multi-layer light-polarization structures with specific orientations of the optical axes in each layer as well as polychromatic absorption properties. The polarization film possesses a high radiation stability, high temperature stability (up to 200° C.), high color fastness and UV-stability. These properties make such films attractive for the replacement of iodine based external polarizers in current LCD production.
[0010] During the manufacturing process, however, the appearance of defects in the form of horizontal stripes several to ten microns wide is possible. The defects divide the areas with different molecular orientations which are clearly seen in a polarized light as the vertical bands. The sources of such defects are the turbulence of LLC flow, non-uniform properties of the alignment layer and non-optimal deposition conditions. Minimizing the defects is possible by changing the deposition speed and LLCs viscosity, using the corona discharge to prepare the substrate, reducing the shift rate of the substrate and fixing the deposition device position.
[0011] USSR Patent No 697,950 proposes the formation of the internal polarizers using LLCs. The procedure describes the deposition of the lyotropic gel of 1-30 wt/wt % on the surface of the transparent electrodes. The gel is then subjected to a shear flow in the velocity of 10 2 -10 7 sec −1 , e.g. by spin coating. The procedure is followed by baking-out the solvent.
[0012] The proposed technology allows the use of thin light polarization film based on LLCs for the internal LCD polarizers. However the polarization direction cannot be made arbitrarily to follow a specific local distribution, e.g. to follow a mosaic picture with the characteristic size of tens of microns or less. This limitation is due to the poor spatial resolution of the proposed method.
[0013] The purpose of the proposed invention is to develop a new technology for the fabrication of thin neutral or color polarizers, with a desired distribution of the polarization axis, for LCD applications.
SUMMARY OF THE INVENTION
[0014] The objective of the present invention is to provide a new technology for the fabrication of thin photo-patterned (pixelated) polarizers with a desired local distribution of the polarization axis.
[0015] According to the present invention there is provided a method of forming a thin light polarization film on a substrate, comprising the steps of: (a) depositing a thin solid film polarizer onto a flexible polymeric carrier sheet, (b) applying a photo-curable glue onto said substrate, (c) bringing said thin solid film polarizer into contact with said glue, (d) illuminating and curing said glue, and (a) removing said carrier sheet.
[0016] In a preferred embodiment the step of illuminating and curing said glue is carried out by illuminating said glue in a pattern whereby a pattern of cured glue is formed and whereby when said carrier sheet is removed said thin solid film polarizer only remains attached to said glue in said pattern. Regions of glue that are not cured may be removed by a solvent.
[0017] Preferably the illumination is carried out through a patterned mask. This mask may be a shadow mask or a photomask formed by photolithography.
[0018] In a preferred embodiment of the invention the light polarization film is formed on the substrate in a pattern formed by regions of at least two different directions of polarization. This may be achieved by: (a) depositing a first solid thin film polarizer on a first flexible carrier, said first polarizer having a first polarization direction, (b) applying a photo-curable glue to said substrate, (c) bringing said first solid thin film polarizer into contact with said glue, (d) illuminating said glue in a first pattern to form a pattern of cured glue having said first solid thin film polarizer adhered thereto, (e) removing said first flexible carrier leaving said first solid thin film polarizer adhered to said substrate by said glue in said first pattern, (f) depositing a second solid thin film polarizer on a second flexible carrier, said second polarizer having a second polarization direction, (g) applying a photo-curable glue to said substrate, (h) bringing said second solid thin film polarizer into contact with said glue, (i) illuminating said glue in a second pattern to form a pattern of cured glue having said second solid thin film polarizer adhered thereto, and (j) removing said second flexible carrier leaving said second solid thin film polarizer adhered to said substrate by said glue in said second pattern.
[0019] In preferred forms of the invention the light polarization film is divided into pixels having different light polarization directions, and these pixels may be divided into sub-pixels, each sub-pixel being formed with different absorption colors. Alternatively, all the pixels may have the same polarization direction.
[0020] The flexible carrier sheet may be formed of an isotropic or non-isotropic polymeric material, and may include a detachment layer. Preferably the detachment layer also serves as a polarization alignment layer. The detachment layer may comprise a film of material selected from the group consisting of paraffin wax, mineral oils, barium stearate, resins, uniaxially aligned polyethyleneterephthalate or the like. This detachment and alignment layer can be rubbed mechanically to obtain a desired orientation.
[0021] The thin light polarization film is preferably formed on a substrate forming the inner surface of a liquid crystal display.
[0022] According to the present invention there is further provided a method of forming a thin light polarization film comprising the steps of: (a) depositing a layer of photoalignable material on a substrate, (b) illuminating the photoalignable layer with actinic radiation to define a polarization axis of said photoalignable layer, (c) applying a thin layer of an isotropic absorber solution onto said photoalignable layer, (d) partially evaporating said solution to form a gel, and (e) baking said gel to form an anisotropic absorber layer.
[0023] In one embodiment of the invention the actinic radiation is linearly polarized and the principal absorption axis of said photoalignable layer is orthogonal to the polarization vector of said actinic radiation. In another embodiment of the invention the actinic radiation is non-polarized and is incident on said photoalignable layer at an oblique angle.
[0024] Preferably the photoalignable layer is illuminated through a mask whereby only selected regions of said layer are aligned. More preferably still, the photoalignable layer is illuminated through several masks in sequence whereby different regions of said photoalignable layer may be formed with different alignment axes. The photoalignable layer may be illuminated through a photo-patterned mask that transforms linearly polarized or non-polarized actinic radiation into actinic radiation having a spatial distribution of polarization vectors, and this photo-patterned mask may be a light polarization mask or a birefringence mask.
[0025] Preferably more than one absorber material may be provided and different absorbers may be chosen with different colors. The absorber may comprise lyotropic liquid crystal. The photoalignable material may preferably be an organic azodye.
[0026] The photoalignable material may be deposited in a layer of from 0.05 to 1.5 μm thick, while the absorber material may have a thickness of from 0.3 to 1.5 μm.
[0027] Preferably the thin light polarization film is formed on a substrate forming an inner surface of a liquid crystal cell.
[0028] Viewed from a still further aspect the present invention provides a thin light polarization film deposited on a substrate and comprising a plurality of pixels, wherein said pixels are formed with different axes of polarization. This light polarization film may be formed on the internal surface of a substrate defining a liquid crystal cell.
BRIEF DESCRIPTION OF THE DRAWINGS
[0029] Some embodiments of the invention will now be described by way of example and with reference to the accompanying drawings, in which:
[0030] [0030]FIG. 1 illustrates a lyotropic liquid crystal coated on a polymeric film for the preparation of a thin film polarizer,
[0031] [0031]FIGS. 2 a - c show (a) a high level flow chart showing the process of the fabrication of a photo-patterned (pixelated) polarizer in accordance with a first embodiment of the present invention (photo-hardened adhesives), and (b) & (c) schematically ilustrate the process,
[0032] [0032]FIGS. 3 a - c illustrate possible methods for the formation of photo-patterned (pixelated) mono- or polychromatic and/or dichroic thin film polarizers,
[0033] [0033]FIGS. 4 a - b show (a) a high level flow chart showing the process for the fabrication of a photo-patterned (pixelated) polarizer in accordance with a second embodiment of the present invention,
[0034] [0034]FIG. 5 shows structural formulae of the photochemical stable azodyes that may be used for the preparation of photo-alignment layers,
[0035] [0035]FIG. 6 schematically illustrates the use of oblique exposure of a photo-alignment layer with a non-polarized light,
[0036] [0036]FIG. 7 schemattically illustrates possible methods for the formation of photo-patterned (pixelated) thin film polarizers using obliquely incident non-polarized light,
[0037] [0037]FIG. 8 shows transmission spectra of the azodye AD-1 before and after the exposure by a polarized light (T p and T s represent respectively the transmission spectrum perpendicular and parallel to the dye absorption axis, whereas T 0 is the transmission spectrum before UV irradiation),
[0038] [0038]FIG. 9 shows polarized transmission spectra of a thin lyotropic polarizer (T p and T s represent respectively the transmission spectrum perpendicular and parallel to the azodye absorption axis), and
[0039] [0039]FIG. 10 schematically illustrates a single large pixel covering the whole display area when all the local axes are aligned in a particular direction.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0040] The present invention proposes the use of two technological solutions to obtain photo-patterned (pixelated) thin light polarization films, with different polarization axis and/or different local color regions, for LCD production. Both solutions are based on the application of lyotropic liquid crystals (LLCs). In the first variant, the neutral and/or color polarizers are obtained using photo-hardened adhesive, while the second variant uses a photo-alignment layer to obtain neutral and/or color LLC polarizers.
[0041] In FISG. 2 a - c , a flow chart 200 of one example process for the fabrication of patterned (pixelated) polarizers in accordance with this invention is shown. At the first step, the method shown in FIG. 1 is used to prepare a thin polarization film 201 (FIG. 2 b ). The polarizer 201 comprises a thin solid substance, which exhibits a nematic state in an organic solvent. The solid film is coated on the flexible polymeric carrier sheet 202 . The surface of the sheet 202 may be treated for anisotropic LLC orientation. The treatment includes, in particular, the deposition of a thin layer of a paraffin wax, mineral oil, barium stearate, a resin or other materials. The surface of this layer is then rubbed or brushed. To diminish the adhesion of the anisotropic solid film 201 to the carrier 202 , which is needed for the separation of the polarizer 201 from the carrier 202 , a detachment layer 203 of 1 μm thick can be included. This layer can be formed e.g. from paraffin wax or other easy-melting substances. The flexible carrier sheet may be composed of low-cost polymer sheets of polyethyleneterephthalate (PET) film with a weak adhesion to the thin film polarizer 201 in which case an additional detachment layer may not be necessary.
[0042] To transfer the thin film polarizer 201 onto the substrate 204 , the top surface of the substrate 204 is coated with a photo-polymerized glue 205 . Then, the flexible polymeric carrier sheet 202 with the thin film polarizer 201 is put in contact with the substrate 204 . The orientation of the carrier sheet 202 is maintained for a particular polarization axis with respect to the substrate 204 . The stacked construction is pressed 206 to obtain a uniform thin layer 207 of the photo-polymerized glue. Vacuum pressing may help reduce the air bubbles trapped inside the thin layer 207 . UV glue (e.g. Norland 65 ) should not dissolve the thin polarizer layer 201 .
[0043] Afterwards, an aperture mask 209 is illuminated by UV light 208 and an image of the mask is projected by a lens 210 onto the thin layer 207 . The illuminated regions 211 will be hardened and the hardened parts 211 of the UV-glue bond strongly to the thin film polarizer 201 on one side and the substrate on the other. The non-hardened parts of the UV glue 214 can be removed from the substrate by an organic solvent. In this way, a photo-patterned polarizer structure can be obtained after the polarization film is separated mechanically from the substrate.
[0044] To obtain a photo-patterned (pixelated) polarizer with different local orientations of the polarization axis, the operations I-VI (FIG. 2 b ) are repeated with a set of thin film polarizers 201 oriented at different directions and with corresponding aperture masks. The feature size of thin film polarizers (pixels) obtained in this manner can be less than 10 μm.
[0045] A dry photo-polymerized glue (e.g. produced by Du Pont de Nemours) can be used for the purpose of pattern transfer. The structure of the dry photo-polymerized glue is shown in FIG. 2 c . The structure includes a flexible and dry photo-polymerized glue film 215 and two protection layers 216 and 217 . At the first step, the protection layer 217 is taken away and the dry glue film 215 is laminated onto the surface of the substrate 204 before the other protection layer 216 is removed. Afterwards, the above mentioned operations (IV-VII) are repeated as shown in FIG. 2 b.
[0046] In FIGS. 3 a - c , possible variants of the formation of photo-patterned mono- or polychromatic thin film polarizers with different local axis orientation are illustrated. The letters R( 302 ), G( 303 ), B( 304 ), G B ( 305 ) and D( 306 ) denote Red, Green, Blue, Gray (Black) and Dichroic polarizers respectively, whereas the arrow 301 shows the direction of the optical axis orientation in the corresponding pixels. The technology of the present invention allows thin (0.3-1 μm thick) photo-patterned (pixelated) polarizers to be obtained, which are either neutral or color, for LCDs applications.
[0047] In FIGS. 4 a - b , another method for the fabrication of photo-patterned (pixelated) polarizers in accordance with this invention is shown. The thin film polarizers are prepared by evaporation of the LLC isotropic solution onto a photo-alignment layer. In this procedure, an initially isotropic solid film exhibiting photo-induced optical anisotropy is used as an alignment layer. The photo-induced anisotropy and the absorption dichroism are formed in the alignment film as a result of the reversible (photochromic) or irreversible (photochemical) reactions. When the molecules absorb either polarized or non-polarized quanta of light, a molecular order is formed on the surface and in the bulk of such a photo-alignment layer. The degree of molecular order depends on the exposure energy, while the direction of the preferred molecular orientation is defined by the polarization vector and the plane of light incidence.
[0048] Due to the molecular dispersion forces between the photo-alignment film and the lyotropic liquid crystal, a homogeneous orientation of the whole lyotropic layer can be made possible. It has been discovered that certain organic photochemical stable substances, illuminated by a polarized or non-polarized light, show a much higher degree of induced molecular order than that found in an active photochemical molecular layer. The molecular order, which was evaluated by the photo-induced optical anisotropy, becomes saturated in the photo-chromic substances. This is contrary to the case where the molecular order is due to the irreversible photo-chemical reaction. In the latter case, the induced optical anisotropy decreases for sufficiently high exposure energy, i.e. the molecular order depends on the exposure energy critically.
[0049] In addition it is possible to induce the photo-alignment for a lyotropic liquid crystal, using obliquely incident non-polarized light. In this case, the molecular order in the photo-alignment layer increases with the exposure energy. The preferred orientation of the lyotropic molecules is parallel to the plane of oblique incidence and depends on the interaction between the lyotropic and dye molecules. Thus expensive UV-polarizers can be eliminated and the whole production process of thin internal polarization films can be considerably simplified.
[0050] Azodye AD-1 with the following structural formula is used:
[0051] This azodye is a photo-chemically stable substance for the photo-alignment. The structural formulae of the other photo-chemically stable azodyes, which can be used for the preparation of photo-alignment layer are given in FIG. 5.
[0052] The fabrication process 400 in accordance with this embodiment of the present invention is shown in FIG. 4 a . At the first step of the process 400 (FIG. 4 b ), a photo-alignment layer 402 with a thickness of 10-200 nm is deposited on the top of the glass or plastic substrate 401 . An amorphous film of the photo-chemically stable azodye AD-1 may be used as the photo-alignment film 402 . The film was produced by spin coating, but thermal sputtering in vacuum can be used. The film 402 can also be deposited by dipping the substrate 401 in the solution of the substance AD-1. After the formation of the solid film 402 , it is illuminated by light source 405 . The polarizer 406 , aperture mask 404 and the lens 403 constitute a simple imaging system for the photo-pattern transfer. The operation II should be repeated to obtain a locally distributed polarization axis on the photo-patterned (pixelated) polarizers. A different set of aperture masks and polarization vectors can be used for this purpose. The polarizer 406 can be eliminated, if the photo-alignment film is exposed by non-polarized light at an oblique incidence (FIGS. 6 & 7).
[0053] After the steps II and III have been completed (FIG. 4 a ), the local polarization axis 408 is formed in the illuminated regions of the thin film 407 (FIG. 4 b ), and the regions 409 where they are not illuminated show a random axis orientation. The isotropic solution 410 of the lyotropic liquid crystal 411 is then coated onto the top of the photo-alignment layer. The lyotropic nematic ordering is restored at a certain concentration of the solvent. The desired concentration is achieved after the partial evaporation of the solvent 412 , giving rise to the formation of a viscous gel film 413 . The local orientations of the lyotropic molecules 414 are influenced by the local molecular order 409 in the photo-alignment layer 407 . The baking-out of the solvent 415 from the lyotropic film 413 is made using a heater 416 . This results in the formation of a highly ordered film 417 of the lyotropic liquid crystal with a high extinction ratio.
[0054] Thus, the technology proposed allows the obtaining of a thin (0.3-0.5 μm) one-layer film, which can be used as a neutral or color photo-patterned (pixelated) internal polarizer for LCDs. The minimal element size can be of the order of a few microns. To make a polychromatic polarizer, the lyotropic layer 417 can be coated by a new photo-alignment layer, and the operations II-VII can be repeated with other compositions of lyotropic liquid crystals. The isolation layers can be placed between different lyotropic polarization films if necessary (not shown in FIG. 4 b ). The total thickness of the final sandwiched photo-patterned (pixelated) polarizer can reach several microns.
[0055] Dependent on the chemical structure of the lyotropic liquid crystals, the polarization axis can be oriented either parallel or perpendicular to the molecular axis of the photo-alignment layer. For instance, the preferred orientation of the lyotropic liquid crystals (Crystal Ink™) from OPTIVA Inc. is perpendicular to that of the AD-1 dye molecules in the photo-alignment layer. This allows a thin photo-patterned (pixelated) polarizer to be obtained using the azodye AD-1 and the lyotropic liquid crystals (Crystal Ink™) from OPTIVA Inc. The thickness of the polarizer was about 0.3-1.5 μm. The AD-1 layer was illuminated by a polarized light near the wavelength of the maximum absorption. The initially colored layer became transparent along the polarization direction of the illumination and highly absorptive at the orthogonal direction (FIG. 8). At the same time the average optical density D av :
D av =( D ∥ +2 D ⊥ )
[0056] remained practically the same. The polarization transmission spectra on the glass substrate of the thin internal lyotropic polarizer, prepared from the azodye AD-1 and lyotropic liquid crystals (Crystal Ink™) from OPTIVA Inc are shown in FIG. 9. In both technological solutions proposed in this invention, the special case is illustrated in FIG. 10 when all the local axes degenerate into a single direction using a linearly polarized light.
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This invention relates to methods for preparing photo-patterned mono- or polychromatic, polarizing films. The polarizer can be pixelated into a number of small regions wherein some of the regions have one orientation of the principal neutral or color absorbing axis; and some other of the said regions have another orientation of the principal neutral or color absorbing axis. The axis orientation is determined by the polarization vector of actinic radiation and the multi-axes orientation is possible by a separated masked exposure. This polarizer can be placed on the interior substrate surface of the LCD cell.
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BACKGROUND OF THE INVENTION
The present invention concerns a winding apparatus for threads or yarns with a bobbin support roll and a friction drive drum, which rolls are arranged mutually parallel and with their rotational axes contained superimposed in a substantially vertical plane, and one of which rolls being subject to the movements caused by the increase of the bobbin packages being built on the bobbin support roll, which movements are effected in guides substantially parallel to the plane, one of the rolls being pivotable in movements parallel to the plane about a pivoting axis, and the bobbin support roll being supported rotatably in a bearing located at one of its ends.
Winding of threads, yarns and similar strands on a chuck or mandrel, or onto a bobbin support roll, respectively, is a known process, the roll being supported at one side only, for operational reasons. Rotation of the bobbin support roll is effected by surface friction drive using a friction drive roll arranged parallel to the support roll and pre-tensioned with respect to it. Due mainly to the bobbin package weight increase during the winding process and due to the elastic support on the bobbin support roll, the two rolls do not remain exactly parallel during the winding process. Thus, the contacting pressure of the friction drill roll no longer is equal over the length of the bobbin support roll, such that conical bobbin packages are produced. This disadvantage is all the more considerable, the bigger and larger the bobbin packages are. If on the bobbin support roll a plurality of bobbin packages is wound simultaneously, these packages additionally differ. Thus, the production of correct bobbin packages is rendered more difficult or impossible.
From German Patent Publication No. 2,649,555 already a "self-aligning" arrangement of the friction drive roll is known. In this arrangement the latter is pivotable about an axis at right angles with respect to the rotational axis, in such manner, that owing to the pressure directed towards the bobbin support roll the friction drive roll always aligns itself parallel to the bobbin support roll. From German Patent Publication No. 2,058,513 an arrangement is known, in which the bobbin support roll aligns itself parallel to the friction drive roll. These designs incorporating a self-aligning arrangement require a complicated structure of the pivotable roll. The latter furthermore is unstable to a certain extent, which causes the excitation of vibrations, which induce wear and fractures.
On the other hand, the support roll and the friction drive roll can also be mutually aligned in such manner that they are in their mutually exactly parallel position while the bobbin packages are half built, i.e. that at the beginning of the winding process, e.g. the support roll with its free end is inclined slightly towards the friction drive roll and at the end of the winding process is slightly inclined away from it. Such machines, operating with a "mean value setting" of this type, yield better results than machines on which no measures have been taken. They perform satisfactorily only, however, for one certain bobbin package diameter to be produced. The bobbins produced still are uneven and their quality is unsatisfactory.
SUMMARY OF THE INVENTION
It thus is an important object of the present invention to eliminate the disadvantages cited. The invention is characterized in that a coupling means is provided, by means of which the movements cause rotating movements of the pivotable roll about the pivoting axis in the sense of a forcible parallelization of the rolls.
BRIEF DESCRIPTION OF THE DRAWINGS
The invention is described in more detail in the following with reference to illustrated design examples. There is shown in:
FIG. 1 a sectional side view of a bobbin support roll and a friction drive roll which, according to the present invention, are maintained in a parallel position at all times.
FIG. 2 a schematic view of an example of a coupling and control system.
FIG. 3 a schematic view of a further example of a coupling and control system.
FIG. 4 a sectional side view of a further embodiment for maintaining the two rolls parallel.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
In FIG. 1 a bobbin support roll 11 is shown, on which four thread bobbin packages 12 have been built or are being built by winding. The roll 11 is rotatable about its rotational axis 13. Above the roll 11 a friction drive roll 14 is rigidly supported in bearings 15 and is rotatable about its rotational axis 16. The arrangement is chosen in such manner that the two axes 13 and 16 are located in a vertical plane. The roll 14 is driven by a motor 17.
The end of the bobbin support roll 11 shown at the left hand side of FIG. 1 is a free end. This end is kept free for permitting unobstructed doffing of the finished bobbin packages 12. On its right hand side the roll 11 is elastically supported in a rotation bearing 21 for avoiding vibrations. The bearing 21 is mounted on a sliding support member 22 which is movably arranged in guides 23. The guides 23 are arranged parallel to the plane defined by the axes 13, 16. Thus, the movements of the sliding support member 22 also are effected parallel to this plane. The support member 22 can be designed as sliding on the guides 23 or movable on rolls. The rotation bearing 21 is mounted on the sliding support member 22 in such manner that it is pivotable about a pivoting axis 24 supported thereon. In this arrangement the pivoting movements also are effected parallel to the plane defined by the axes 13, 16. Thus also the support roll 11 is pivotable about the pivoting axis or shaft 24 in this plane. The rotation bearing 21 furthermore is connected with an activating or actuation member 26 which is supported on a rotation element 25. The rotating or rotation element 25 also is supported by the support member 22, and it is rotatable about an eccentric axis or shaft 28 using a control element 27. The control element 27 is coupled via a pivoting or pivotal arm 29 with a fixed part of the winding apparatus. The element 25 forms the coupling point at which the control element 27 is coupled to the activating element 26.
The bobbin support roll 11 together with the rotation bearing 21 and the sliding support member or carriage 22 are pressed against the friction drive roll 14 at all times. This can be effected, e.g. if the sliding support member 22 is subject to a corresponding pressure at all times.
During the build-up of bobbin packages the motor 17 drives the roll 14. Owing to the above mentioned pressure, to which the roll 11 is subjected to at all times, the roll 11 is entrained. The increase in size of the bobbin packages 12 during the winding process causes the roll 11 to move gradually downward, while the sliding support member 22 is correspondingly moved. As the size of the bobbin packages 12 increases, also their weight increases. This causes a slight deflection of the roll 11 and a slight yielding of the bearing 21, the bearing 21 being designed as an elastic bearing. Thus the free end of the roll 11 moves downward somewhat. Even if it moves generally, only over a few millimeters at the most, the resulting deviation of the rolls 11 and 14 from their parallel position causes the bobbin packages 12 produced under such conditions to be affected by the disadvantages mentioned initially. According to the present invention, in the embodiment according to FIG. 1, a coupling means 20 is provided, which comprises the parts 25 through 28 and which forcibly achieves parallel alignment of the rolls 11 and 14. As the support roll 11 moves downward while the diameter of the bobbin packages 12 increases, also the sliding support member 22 moves downward and with it also the eccentrically supported rotating element 25. Consequently the control element 27 pivots clockwise about the axis 32 and causes an also clockwise rotation of the rotating element 25 about the axis 28. This rotation of the element 25 causes the activating member 26 to move down relative to the sliding support member 22. Thus the rotation bearing 21 is pivoted about the axis 24 also clockwise.
The setting and the eccentricity of the rotating element 25 are to be adapted to the increase in bobbin package weight in such manner that the parallel alignment is maintained during all phases of the winding process. Thus, of course, for e.g. bobbin packages of different widths or for different winding densities, different distances of the centre of the rotating element 25 from the rotational axis 28 and/or correspondingly chosen initial settings for the rotational position of the element 25 are to be chosen. Also the influence of a contact pressure upon the friction drive roll, which varies widely over the build-up of the bobbin packages, can be corrected in such manner.
In FIG. 2 an arrangement is shown, in which the size of the pivoting motion of the control element 27 can be pre-set in a simple manner. In FIG. 2 the lower part only of the sliding support member 22 is shown, and otherwise again the presence of the winding apparatus according to FIG. 1 is assumed. The sliding support member 22 again supports the rotation bearing 21, and at a stepped portion, the rotation element 25. The rotation element 25 in turn is supported eccentrically and rotatable about the rotational axis or shaft 28. The activating or actuation member 26 connects the element 25 with the rotation bearing 21 and causes its pivoting about the pivoting axis or shaft 24. The control element 27 is rigidly connected to the rotation element 25 and, together with it, is pivotable about the axis 28. At its free end at the control element 27 a follower roll 33 is arranged, which is provided for moving along a control cam curve or control cam 34 as the sliding support member 22 moves up or down. The control element 27 is pressed against the cam curve 34 at all times by a spring 35. The elements 25, 26, 27, 33, 34, 35 form a coupling means 30.
As the sliding support member 22 moves downward, the cam curve 34 causes pivoting of the control element 27 in the clockwise sense. Consequently also the rotating element 25 is rotated in the same sense, such that in the situation of the element 25 illustrated, the element 25 moves the activating element 26 downward with respect to the sliding support member 22. Thus the rotation bearing 21 is pivoted clockwise about the pivoting axis 24.
By using control cam curves or control cams 34 of suitable shape, any desired sequence of movements of the bobbin support roll 11 can be achieved. As indicated by slots 36 and screws 37, the position of the control cam curve 34 can be changed by movably mounting a plate 38, supporting the control cam curve 34, on a fixed part of the winding apparatus. Instead of using the depicted control cam curve 34 also an appropriately formed slot in which a sliding member fixed to the control element slides, can be provided instead of the follower roll.
It should be noted in this context, that the use of an element 25 formed as eccentric device presents the advantage that a large movement of the control element 27, in simple manner, can be transformed into a small movement of the activating member 26. This means that by using a small control force a great force can be exerted upon the roll to be pivoted, and that practically no reaction by the latter is exerted onto the control element 27.
In FIG. 3 a further possibility of a control arrangement for the position of the support roll 11 with respect to the friction drive roll is shown. The rotation bearing 21, which again is supported on a sliding support member 22 by a pivoting axis or pivot shaft 24, is connected via an activation or actuation member 41 formed as a piston rod with a piston 43 provided in a cylinder 42. Via the duct 44 and via the control valve 45 a gaseous or liquid medium is supplied to the cylinder 42, which liquid medium is furnished from the reservoir 46. The control of the control valve 45 is effected by the control element 47.
The duct 44 is flexible such that a movement of the sliding support member 22 with respect to the control valve 45, which is fixed to the apparatus, is rendered possible. As the sliding support member 22 moves up or down, the control element 47 is moved together with the sliding support member 22 and exerts a control action onto the valve 45. This control arrangement is laid out such, that in the roll arrangement shown in FIG. 1, the pressure within cylinder 42 is increased as the sliding support member 22 moves downward. In this manner a pivoting motion of the rotation bearing 21 clockwise about the pivoting axis or pivot shaft 24 is achieved, and thus the lowering of the free end of the bobbin support roll 11 during the winding process is compensated for.
A further alternative design example of a winding apparatus according to the invention is shown in FIG. 4. In this arrangement again a friction drive roll 64 is driven by a motor 17. The roll 64 and the motor 17 are rotatably mounted in a support frame 51. The frame 51 is pivotable about the pivoting axis or pivot shaft 52 and is supported thereat. At its other end, shown at the right in FIG. 4, the frame is held by a pin 53. A bobbin support roll 61 on which bobbin packages 12 are built, again is elastically supported in a rotation bearing 21. The axes 13, 16 of the rolls 61 and 64 again are arranged in a substantially vertical plane. Arranged parallel to this plane again are guides 23 formed by guide rails, in which a sliding support member 22 is movable substantially parallel to this plane.
A two-armed or double-arm lever 54 is slidably and pivotably supported with its one end in a slot 55 in the sliding support member 22. In the vicinity of its other end it is pivotable about a shaft 56 which is combined to a part fixed to the apparatus. The pin 53 and an axis or shaft 57 at the short end of the lever 54 are connected by a link designed as an activating or actuation member 58. The axis or shaft 57 can be mounted to the short lever arm in any known manner at different, selectable distances from the shaft 56. The elements 53 through 58 form a coupling means 50 and the axis or shaft 57 is the coupling point at which the control element 54 is coupled to the activating member 58.
As the diameters of the thread bobbin packages 12 increase during the winding process, the bobbin support roll 61 and the rotation bearing 21 move downward together with the sliding support member 22. Consequently the lever 54 is pivoted counter-clockwise about the shaft 56 in such manner that the axis 57 is moved upward. The activating member 58 thus lifts the pin 53 in such manner that the support frame 51 and thus the friction drive roll 64 again are brought into a position parallel to the support roll 61. The selectable, variable distances between the shaft 56 and the axis 57 are used for adaption to various thread types, and to the winding density of the bobbin package 12 chosen.
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 practiced within the scope of the following claims. ACCORDINGLY
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The present invention concerns an apparatus for winding threads or yarns and similar strands, in which a friction drive roll and a bobbin support roll are provided. The latter is supported only at one end, and the other end is free, in such manner that easy operation is possible. In arrangements of such type any deviation, however small, of the two rolls from their correct, parallel position, is to be avoided if correctly built bobbin packages are to be produced in the winding process. This is achieved according to the invention in that a coupling means, coupled or connected with the bobbin support roll, which moves during the winding process, brings about a forcible parallel alignment of the two rolls.
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BACKGROUND OF THE INVENTION
[0001] The present invention relates to a pattern formation method, and more particularly, it relates to a pattern formation method of forming a resist pattern used for forming a semiconductor device or a semiconductor integrated circuit on a semiconductor substrate by using exposing light of a wavelength of a 1 nm through 180 nm band.
[0002] As exposing light used in forming a resist pattern through pattern exposure of a resist film formed on a semiconductor substrate, KrF excimer laser has been put to practical use. Also, a device including a semiconductor device or a semiconductor integrated circuit formed by using a resist pattern obtained by the pattern exposure using the KrF excimer laser is almost commercially available.
[0003] In this case, a resist material including a phenol resin is mainly used as a resist material to be pattern-exposed with the KrF excimer laser.
[0004] For further refinement of a semiconductor device or a semiconductor integrated circuit, ArF excimer laser with a shorter wavelength than the KrF excimer laser is used as the exposing light. A resist material including an acrylic acid type resin is mainly under examination as a resist material used in the pattern exposure with the ArF excimer laser.
[0005] In order to realize further refinement of a semiconductor device or a semiconductor integrated circuit, however, it is necessary to use, as the exposing light, a laser beam with a wavelength shorter than that of the ArF excimer laser, such as a Xe 2 laser beam (with a wavelength of a 172 nm band), a F 2 laser beam (with a wavelength of a 157 nm band), a Kr 2 laser beam (with a wavelength of a 146 nm band), an ArKr laser beam (with a wavelength of a 134 nm band), an Ar 2 laser beam (with a wavelength of a 126 nm band) or a soft X-ray beam (with a wavelength of a 13, 11 or 5 nm band).
[0006] Therefore, the present inventors have formed a resist pattern from a resist film of a known resist material through pattern exposure using a F 2 laser beam. Now, a method of forming a resist pattern from a known resist material will be described with reference to FIGS. 6 ( a ) through 6 ( d ).
[0007] First, a resist material having the following composition is prepared:
Base polymer: 2 g poly((2-methyl-2-adamantylmethacrylate) (30 mol %)- (t-butylmethacrylate) (30 mol %)-(methylmethacrylate) (30 mol %)-(methacrylic acid) (10 mol %) Acid generator: triphenylsulfonium triflate 0.4 g Solvent: diglyme 20 g
[0008] Then, as is shown in FIG. 6( a ), the resist material having the aforementioned composition is applied by spin coating on a semiconductor substrate 1 , thereby forming a resist film 2 with a thickness of 0.5 μm.
[0009] Next, as is shown in FIG. 6( b ), the resist film 2 is irradiated with a F 2 laser beam 4 through a mask 3 for pattern exposure. In this manner, an acid is generated from the acid generator in an exposed portion 2 a of the resist film 2 while no acid is generated in an unexposed portion 2 b of the resist film 2 .
[0010] Then, as is shown in FIG. 6( c ), the semiconductor substrate 1 is heated with a hot plate, for example, at 100° C. for 60 seconds.
[0011] Thereafter, the resist film 2 is developed with an alkaline developer, such as a 2.38 wt % tetramethylammonium hydroxide developer. Thus, the resist pattern is formed.
[0012] The resultant resist pattern 5 has, however, a defective pattern shape as is shown in FIG. 6( d ).
[0013] The resist pattern 5 similarly has a defective pattern shape not only when the F 2 laser beam is used as the exposing light but also when light of a wavelength of a 1 nm through 180 nm band is used.
SUMMARY OF THE INVENTION
[0014] In consideration of the aforementioned conventional problem, an object of the invention is forming a resist pattern in a good pattern shape through pattern exposure using light of a wavelength of a 1 nm through 180 nm band as exposing light.
[0015] The present inventors have concluded that the resist pattern has a defective pattern shape because the resist film has a high absorbing property against light of a wavelength of a 1 nm through 180 nm band, and examined various means for decreasing the absorbing property against light of a wavelength of a 1 nm through 180 nm band. As a result, it has been found that the absorbing property of the resist film against light of a wavelength of a 1 nm through 180 nm band can be decreased when the resist material includes a halogen atom, a cyano group, a nitro group, an alkoxy group, an amino group, an alkyl group, a trifluoromethyl group or a mercapto group.
[0016] Then, the inventors have examined the reason why the absorbing property against light of a wavelength of a 1 nm through 180 nm band can be decreased when the resist material includes a halogen atom, a cyano group, a nitro group, an alkoxy group, an amino group, an alkyl group, a trifluoromethyl group or a mercapto group. As a result, it has been found that such an atom or a group has a property to shift the absorption wavelength band against the exposing light inherent in the resist material or to decrease the absorbing property of the resist material against light of a short wavelength band.
[0017] Now, referring to FIG. 1, an example to verify that the peak of a light absorption wavelength of a resist material against exposing light is shifted toward a longer wavelength when a base polymer of the resist material includes an amino group will be described.
[0018] [0018]FIG. 1 is a graph for explaining that the absorption zone of the exposing light is shifted by substituting an amino group for an aromatic ring of poly(vinyl phenol). In the graph of FIG. 1, a broken line indicates the absorption wavelength of poly(vinyl phenol) in which an amino group is not substituted for the aromatic ring; and a solid line indicates the absorption wavelength of an o,o-b 2 substitution product obtained by substituting an amino group for the aromatic ring of poly(vinyl phenol). As is understood from FIG. 1, the peak of the absorption wavelength, which is a 190 nm band when an amino group is not substituted, is shifted toward a longer wavelength by approximately 30 nm when an amino group is substituted.
[0019] When the peak of the absorption wavelength zone of the resist film is a 190 nm band, the resist film has poor transmittance against a F 2 laser beam with a wavelength of a 157 nm band. However, when the peak of the absorption wavelength zone is shifted from a 190 nm band toward a longer wavelength by approximately 30 nm, the transmittance against the F 2 laser beam is increased.
[0020] Also Japanese Laid-Open Patent Publication No. 60-254041 discloses a resist material including fluorine, that is, one of halogen atoms, in its base polymer. This resist material includes, in the polymer, α-trifluoromethyl acrylic acid and an ester of alcohol having an electron attractive group as one repeating unit. The publication describes that the sensitivity of the resist material against an electron beam can be thus improved.
[0021] However, while an electron beam is used as exposing light in the description of Japanese Laid-Open Patent Publication No. 60-254041, the exposing light is light of a wavelength of a 1 nm through 180 nm band in this invention, and thus, the exposing light is completely different in the wavelength band. Furthermore, while the base polymer includes a halogen atom for the purpose of improving the sensitivity against an electron beam in the description of Japanese Laid-Open Patent Publication No. 60-254041, the polymer includes a halogen atom for the purpose of improving the transmittance against exposing light of a wavelength of a 1 nm through 180 nm band in this invention. Thus, these techniques are completely different in the technical idea.
[0022] Specifically, the pattern formation method of this invention comprises a resist film forming step of forming a resist film by applying, on a substrate, a resist material including at least one atom or group selected from the group consisting of a halogen atom, a cyano group, a nitro group, an alkoxy group, an amino group, an alkyl group, a trifluoromethyl group and a mercapto group; and a pattern forming step of forming a resist pattern by irradiating the resist film with exposing light of a wavelength of a 1 nm through 180 nm band for pattern exposure and developing the resist film after the pattern exposure.
[0023] In the pattern formation method of this invention, since the resist material includes a halogen atom, a cyano group, a nitro group, an alkoxy group, an amino group, an alkyl group, a trifluoromethyl group or a mercapto group, the absorption wavelength of the resist film against the exposing light is shifted toward a longer wavelength, or the absorbing property of the resist film against the exposing light of a short wavelength is decreased. Accordingly, the absorbing property against light of a wavelength of a 1 nm through 180 nm band can be decreased, and hence, the transmittance against light of a wavelength of a 1 nm through 180 nm band can be increased. As a result, a resist pattern can be formed in a good pattern shape through the pattern exposure using light of a 1 nm through 180 nm band as the exposing light.
[0024] In the pattern formation method, the atom or group is preferably bonded to a main chain, a side chain, a hetero ring or carbon constituting a double bond of a base polymer of the resist material.
[0025] In the pattern formation method, the atom or group is preferably a halogen atom bonded to an ester portion of an acrylic resin serving as a base polymer of the resist material.
[0026] In the pattern formation method, the resist material is preferably a chemically amplified resist.
[0027] When the resist material is a chemically amplified resist, the atom or group is preferably included in a protecting group of a base polymer, a crosslinking agent or an agent for inhibiting dissolution of the base polymer of the chemically amplified resist.
[0028] In the pattern formation method, a base polymer of the resist material preferably includes poly(vinyl phenol), poly(vinyl alcohol), an acrylic acid, a novolak resin or a derivative thereof in which a fluorine atom is substituted for a hydrogen atom.
[0029] The pattern formation method of this invention preferably further comprises, between the resist film forming step and the pattern forming step, a step of forming, on the resist film, a water-soluble polymer film from a water-soluble polymer including a halogen atom, a cyano group, a nitro group, an alkoxy group, an amino group, an alkyl group, a trifluoromethyl group or a mercapto group.
[0030] In this case, the water-soluble polymer is preferably polyacrylic acid, poly(vinyl alcohol), poly(vinyl pyrrolidone) or polystyrenesulfonic acid.
[0031] Alternatively, the pattern formation method of this invention preferably further comprises, between the resist film forming step and the pattern forming step, a step of forming, on the resist film, a water-soluble polymer film from a compound including a halogen atom, a cyano group, a nitro group, an alkoxy group, an amino group, an alkyl group, a trifluoromethyl group or a mercapto group, and a water-soluble polymer.
[0032] In this case, the compound is preferably trifluoroacetic acid, trifluoromethylsulfonic acid or a surfactant including fluorine.
[0033] Also in this case, the water-soluble polymer is preferably polyacrylic acid, poly(vinyl alcohol), poly(vinyl pyrrolidone) or polystyrenesulfonic acid.
[0034] In the pattern formation method, the exposing light is preferably a F 2 laser beam or an Ar 2 laser beam.
BRIEF DESCRIPTION OF THE DRAWINGS
[0035] [0035]FIG. 1 is a diagram for illustrating the principle of the invention for explaining that a light absorption wavelength band is shifted by substituting an amino group for an aromatic ring of poly(vinyl phenol);
[0036] FIGS. 2 ( a ) through 2 ( d ) are sectional views for showing procedures in a pattern formation method according any of Embodiments 1 through 9 of the invention;
[0037] FIGS. 3 ( a ) through 3 ( d ) are sectional views for showing procedures in a pattern formation method according to Embodiment 10 of the invention;
[0038] FIGS. 4 ( a ) through 4 ( e ) are sectional views for showing procedures in a pattern formation method according to Embodiment 11 or 12 of the invention;
[0039] FIGS. 5 ( a ) through 5 ( c ) are sectional views for showing procedures in a pattern formation method according to Embodiment 13 of the invention;
[0040] FIGS. 6 ( a ) through 6 ( d ) are sectional views for showing procedures in a pattern formation method as a premise of the invention; and
[0041] [0041]FIG. 7 is a diagram for showing the relationship between the wavelength of exposing light and transmittance of resist films each with a thickness of 0.1 μm respectively formed from resist materials according to Modifications 1 and 2 of Embodiment 6 of the invention and a conventional resist material.
DETAILED DESCRIPTION OF THE INVENTION
[0042] Embodiment 1
[0043] In a base polymer of a resist material used in a pattern formation method of Embodiment 1, fluorine atoms are substituted for part of hydrogen atoms bonded to a benzene ring of poly(vinyl phenol). The specific composition of the resist material is as follows:
Base polymer: 1 g poly(o,o-difluoro-p-hydroxystyrene-co-p- (t-butoxy)o,o-difluorostyrene Acid generator: bis(dicyclohexylsulfonyl)diazomethane 0.01 g Solvent: propylene glycol monoethyl ether acetate 4 g
[0044] First, as is shown in FIG. 2( a ), the resist material having the aforementioned composition is applied by spin coating on a semiconductor substrate 10 , thereby forming a resist film 11 with a thickness of 0.3 μm.
[0045] Next, as is shown in FIG. 2( b ), the resist film 11 is irradiated with a F 2 laser beam 13 with a wavelength of a 157 nm band through a mask 12 for pattern exposure. In this manner, an acid is generated from the acid generator in an exposed portion 11 a of the resist film 11 while no acid is generated in an unexposed portion 11 b of the resist film 11 .
[0046] Then, as is shown in FIG. 2( c ), the semiconductor substrate 10 together with the resist film 11 are heated. Although the base polymer is alkali-refractory, it decomposes when heated in the presence of an acid, and hence, the exposed portion 11 a of the resist film 11 becomes soluble in an alkaline aqueous solution.
[0047] Thereafter, the resist film 11 is developed with an alkaline developer, and the exposed portion 11 a of the resist film 11 is dissolved in the developer. As a result, the unexposed portion 11 b of the resist film 11 is formed into a resist pattern 14 as is shown in FIG. 2( d ).
[0048] In the base polymer of Embodiment 1, fluorine atoms are substituted for part of hydrogen atoms bonded to the benzene ring, and hence, the peak of the light absorption wavelength determined by the benzene ring is shifted toward a longer wavelength, resulting in decreasing the absorbing property against light of a wavelength of a 1 nm through 180 nm band. Therefore, the transmittance against the exposing light of a wavelength of a 1 nm through 180 nm band is increased, and hence, the exposing light can sufficiently reach the bottom of the resist film 11. As a result, the resist pattern can be formed in a good sectional shape with a line width of 0.09 μm.
[0049] Modification 1 of Embodiment 1
[0050] Modification 1 of Embodiment 1 is different from Embodiment 1 in the resist material alone, and hence, the resist material alone will be herein described. Specifically, the resist material of Modification 1 includes a base polymer in which chlorine atoms are substituted for part of hydrogen atoms bonded to the benzene ring of poly(vinyl phenol).
Base polymer: 1 g poly(o,o-dichloro-p-hydroxystyrene-co-p- (t-butoxy)o,o-dichlorostyrene Acid generator: bis(dicyclohexylsulfonyl)diazomethane 0.01 g Solvent: propylene glycol monoethyl ether acetate 4 g
[0051] Modification 2 of Embodiment 1
[0052] Modification 2 of Embodiment 1 is different from Embodiment 1 in the resist material alone, and hence, the resist material alone will be herein described. Specifically, the resist material includes a base polymer in which chlorine atoms are substituted for part of hydrogen atoms bonded to the benzene ring of poly(vinyl phenol).
Base polymer: 1 g poly(m,m-dichloro-p-hydroxystyrene-co-p-(t-butoxy)- m,m-dichlorostyrene Acid generator: bis(dicyclohexylsufonyl)diazomethane 0.01 g Solvent: propylene glycol monoethyl ether acetate 4 g
[0053] Embodiment 2
[0054] In a base polymer of a resist material used in a pattern formation method of Embodiment 2, fluorine atoms are substituted for part of hydrogen atoms bonded to a polymer main chain of poly(vinyl phenol). The specific composition of the resist material is as follows:
Base polymer: 1 g poly(p-(2 2-difluorovinyl)phenol-co-p- (1-ethoxyethoxy)-2,2-difluorostyrene) Acid generator: bis(dicyclohexylsulfonyl)diazomethane 0.01 g Solvent: ethylethoxypropyonate 4 g
[0055] First, as is shown in FIG. 2( a ), the resist material having the aforementioned composition is applied by spin coating on a semiconductor substrate 10 , thereby forming a resist film 11 . Then, as is shown in FIG. 2( b ), the resist film 11 is irradiated with a F 2 laser beam 13 with a wavelength of a 157 nm band through a mask 12 for pattern exposure. In this manner, an acid is generated from the acid generator in an exposed portion 11 a of the resist film 11 while no acid is generated in an unexposed portion 11 b of the resist film 11 .
[0056] Next, as is shown in FIG. 2( c ), the semiconductor substrate 10 is heated. Although the base polymer is alkali-refractory, it decomposes when heated in the presence of an acid, and hence, the exposed portion 11 a of the resist film 11 becomes soluble in an alkaline aqueous solution.
[0057] Thereafter, the resist film 11 is developed with an alkaline developer. Since the exposed portion 11 a of the resist film 11 is dissolved in the developer, the unexposed portion 11 b of the resist film 11 is formed into a resist pattern 14 as is shown in FIG. 2( d ).
[0058] In the base polymer of Embodiment 2, fluorine atoms are substituted for part of hydrogen atoms bonded to the polymer main chain, and hence, the absorbing property against light of a short wavelength is decreased. Therefore, the absorbing property against light of a wavelength of a 1 nm through 180 nm band is decreased. Accordingly, the transmittance against the exposing light of a wavelength of a 1 nm through 180 nm band is increased, and hence, the exposing light can sufficiently reach the bottom of the resist film 11 . As a result, the resist pattern can be formed in a good sectional shape with a line width of 0.1 μm.
[0059] Modification of Embodiment 2
[0060] Modification of Embodiment 2 is different from Embodiment 2 in the resist material alone, and hence, the resist material alone will be herein described. Specifically, the resist material includes a base polymer in which trifluoromethyl groups are substituted for part of hydrogen atoms bonded to the polymer main chain of poly(vinyl phenol).
Base polymer: 1 g poly(p-(α-trifluoromethylvinyl)phenol-co-p- (1-ethoxyethoxy)-α-trifluoromethylstyrene) Acid generator: bis(dicyclohexylsulfonyl)diazomethane 0.01 g Solvent: ethylethoxypropyonate 4 g
[0061] Embodiment 3
[0062] In a base polymer of a resist material used in a pattern formation method of Embodiment 3, fluorine atoms are substituted for part of hydrogen atoms bonded to a polymer main chain of poly(vinyl phenol) and part of hydrogen atoms bonded to a benzene ring. The specific composition of the resist material is as follows:
Base polymer: 1 g poly(p-hydroxyheptafluorostyrene-co-p- (t-butoxy)-heptafluorostyrene) Acid generator: triphenylsulfonium triflate 0.01 g Solvent: ethylethoxypropyonate 4 g
[0063] First, as is shown in FIG. 2( a ), the resist material having the aforementioned composition is applied by spin coating on a semiconductor substrate 10 , thereby forming a resist film 11 . Then, as is shown in FIG. 2( b ), the resist film 11 is irradiated with a F 2 laser beam 13 with a wavelength of a 157 nm band through a mask 12 for pattern exposure. In this manner, an acid is generated from the acid generator in an exposed portion 11 a of the resist film 11 while no acid is generated in an unexposed portion 11 b of the resist film 11 .
[0064] Next, as is shown in FIG. 2( c ), the semiconductor substrate 10 is heated. Although the base polymer is alkali-refractory, it decomposes when heated in the presence of an acid, and hence, the exposed portion 11 a of the resist film 11 becomes soluble in an alkaline aqueous solution.
[0065] Thereafter, the resist film 11 is developed with an alkaline developer. Since the exposed portion 11 a of the resist film 11 is dissolved in the developer, the unexposed portion 11 b of the resist film 11 is formed into a resist pattern 14 as is shown in FIG. 2( d ).
[0066] In the base polymer of Embodiment 3, fluorine atoms are substituted for part of hydrogen atoms bonded to the polymer main chain and the benzene ring, and hence, the absorbing property against light of a short wavelength is decreased and the peak of the light absorption wavelength determined by the benzene ring is shifted toward a longer wavelength. Therefore, the absorbing property against light of a wavelength of a 1 nm through 180 nm band is decreased. Accordingly, the transmittance against the exposing light of a wavelength of a 1 nm through 180 nm band is increased, and hence, the exposing light can sufficiently reach the bottom of the resist film 11 . As a result, the resist pattern can be formed in a good sectional shape with a line width of 0.08 μm.
[0067] Modification of Embodiment 3
[0068] Modification of Embodiment 3 is different from Embodiment 3 in the resist material alone, and hence, the resist material alone will be herein described. Specifically, the resist material includes a base polymer in which alkyl groups, such as a methyl group, are substituted for part of hydrogen atoms bonded to the polymer main chain of poly(vinyl phenol) and part of hydrogen atoms bonded to the benzene ring.
Base polymer: 1 g poly(p-hydroxy-α-methyl-o-methylstyrene-co-p- (t-butoxy)-α-methyl-o-methylstyrene) Acid generator: triphenylsulfonium triflate 0.01 g Solvent: ethylethoxypropyonate 4 g
[0069] Embodiment 4
[0070] In a base polymer of a resist material used in a pattern formation method of Embodiment 4, fluorine atoms are substituted for part of hydrogen atoms bonded to a polymer main chain of an acrylic resin. The specific composition of the resist material is as follows:
Base polymer: 1 g poly(α-fluoroacrylic acid-co-α- fluoro tetrahydropyranylacrylate-co- α-fluoro norbornylacrylate) Acid generator: triphenylsulfonium triflate 0.01 g Solvent: propylene glycol monoethyl ether acetate 4 g
[0071] First, as is shown in FIG. 2( a ), the resist material having the aforementioned composition is applied by spin coating on a semiconductor substrate 10 , thereby forming a resist film 11 . Then, as is shown in FIG. 2( b ), the resist film 11 is irradiated with a F 2 laser beam 13 with a wavelength of a 157 nm band through a mask 12 for pattern exposure. In this manner, an acid is generated from the acid generator in an exposed portion 11 a of the resist film 11 while no acid is generated in an unexposed portion 11 b of the resist film 11 .
[0072] Next, as is shown in FIG. 2( c ), the semiconductor substrate 10 is heated. Although the base polymer is alkali-refractory, it decomposes when heated in the presence of an acid, and hence, the exposed portion 11 a of the resist film 11 becomes soluble in an alkaline aqueous solution.
[0073] Thereafter, the resist film 11 is developed with an alkaline developer. Since the exposed portion 11 a of the resist film 11 is dissolved in the developer, the unexposed portion 11 b of the resist film 11 is formed into a resist pattern 14 as is shown in FIG. 2( d ).
[0074] In the base polymer of Embodiment 4, fluorine atoms are substituted for part of hydrogen atoms bonded to the polymer main chain, and hence, the absorbing property against light of a short wavelength is decreased. Therefore, the absorbing property against light of a wavelength of a 1 nm through 180 nm band is decreased. Accordingly, the transmittance against the exposing light of a wavelength of a 1 nm through 180 nm band is increased, and hence, the exposing light can sufficiently reach the bottom of the resist film 11 . As a result, the resist pattern can be formed in a good sectional shape with a line width of 0.1 μm.
[0075] Modification of Embodiment 4
[0076] Modification of Embodiment 4 is different from Embodiment 4 in the resist material alone, and hence, the resist material alone will be herein described. Specifically, the resist material includes a base polymer in which chlorine atoms are substituted for part of hydrogen atoms bonded to a polymer main chain of the acrylic acid, and a protecting group of a hetero ring of the acrylic resin includes a nitro group.
Base polymer: 1 g poly(α-chloroacrylic acid-co-α-chloro-3- nitrotetrahydropyranyl acrylate-co-α-chloro norbornyl acrylate) Acid generator: triphenylsulfonium triflate 0.01 g Solvent: propylene glycol monoethyl ether acetate 4 g
[0077] Embodiment 5
[0078] In a base polymer of a resist material used in a pattern formation method of Embodiment 5, fluorine atoms are substituted for part of hydrogen atoms bonded to a polymer main chain of poly(vinyl alcohol). The specific composition of the resist material is as follows:
Base polymer: 1 g poly(1,2,difluoro-1-hydroxyethylene-co-1,2-difluoro- 1-t-butoxyethylene) Acid generator: diphenyliodonium triflate 0.01 g Solvent: ethylethoxypropyonate 4 g
[0079] First, as is shown in FIG. 2( a ), the resist material having the aforementioned composition is applied by spin coating on a semiconductor substrate 10 , thereby forming a resist film 11 . Then, as is shown in FIG. 2( b ), the resist film 11 is irradiated with a F 2 laser beam 13 with a wavelength of a 157 nm band through a mask 12 for pattern exposure. In this manner, an acid is generated from the acid generator in an exposed portion 11 a of the resist film 11 while no acid is generated in an unexposed portion 11 b of the resist film 11 .
[0080] Next, as is shown in FIG. 2( c ), the semiconductor substrate 10 is heated. Although the base polymer is alkali-refractory, it decomposes when heated in the presence of an acid, and hence, the exposed portion 11 a of the resist film 11 becomes soluble in an alkaline aqueous solution.
[0081] Thereafter, the resist film 11 is developed with an alkaline developer. Since the exposed portion 11 a of the resist film 11 is dissolved in the developer, the unexposed portion 11 b of the resist film 11 is formed into a resist pattern 14 as is shown in FIG. 2( d ).
[0082] In the base polymer of Embodiment 5, fluorine atoms are substituted for part of hydrogen atoms bonded to the polymer main chain, and hence, the absorbing property against light of a short wavelength is decreased. Therefore, the absorbing property against light of a wavelength of a 1 nm through 180 nm band is decreased. Accordingly, the transmittance against the exposing light of a wavelength of a 1 nm through 180 nm band is increased, and hence, the exposing light can sufficiently reach the bottom of the resist film 11 . As a result, the resist pattern can be formed in a good sectional shape with a line width of 0.1 μm.
[0083] Embodiment 6
[0084] In a base polymer of a resist material used in a pattern formation method of Embodiment 6, an alkyl group such as a methyl group is included, and a fluorine atom is substituted for a hydrogen atom bonded to a side chain of the base polymer, in particular, a hydrogen atom in an ester portion of an acrylic resin. The specific composition of the resist material is as follows:
Base polymer: 2 g poly((2-methyl-adamantylmethacrylate) (30 mol %)- (tri(trifluoromethyl)methacrylate (30 mol %)- (methylmethacrylate) (30 mol %)- (methacrylic acid) (10 mol %) Acid generator: triphenylsulfonium triflate 0.4 g Solvent: diglyme 20 g
[0085] First, as is shown in FIG. 2( a ), the resist material having the aforementioned composition is applied by spin coating on a semiconductor substrate 10 , thereby forming a resist film 11 . Then, as is shown in FIG. 2( b ), the resist film 11 is irradiated with a F 2 laser beam 13 with a wavelength of a 157 nm band through a mask 12 for pattern exposure. In this manner, an acid is generated from the acid generator in an exposed portion 11 a of the resist film 11 while no acid is generated in an unexposed portion 11 b of the resist film 11 .
[0086] Next, as is shown in FIG. 2( c ), the semiconductor substrate 10 is heated. Although the base polymer is alkali-refractory, it decomposes when heated in the presence of an acid, and hence, the exposed portion 11 a of the resist film 11 becomes soluble in an alkaline aqueous solution.
[0087] Thereafter, the resist film 11 is developed with an alkaline developer such as a 2.38 wt % tetramethylammonium hydroxide developer. Since the exposed portion 11 a of the resist film 11 is dissolved in the developer, the unexposed portion 11 b of the resist film 11 is formed into a resist pattern 14 as is shown in FIG. 2( d ).
[0088] In the base polymer of Embodiment 6, a methyl group is included and a fluorine atom is substituted for a hydrogen atom bonded to the side chain of the base polymer, and hence, the absorbing property against light of a short wavelength is decreased. Therefore, the absorbing property against light of a wavelength of a 1 nm through 180 nm band is decreased. Accordingly, the transmittance against the exposing light of a wavelength of a 1 nm through 180 nm band is increased, and hence, the exposing light can sufficiently reach the bottom of the resist film 11 . As a result, the resist pattern can be formed in a good sectional shape with a line width of 0.07 μm.
[0089] Modification 1 of Embodiment 6
[0090] Modification 1 of Embodiment 6 is different from Embodiment 6 in the resist material alone, and hence, the resist material alone will be herein described. Specifically, the resist material includes a base polymer in which a fluorine atom is substituted for a hydrogen atom bonded to a side chain of the base polymer, in particular, a hydrogen atom in an ester portion of the acrylic resin. The specific composition of the resist material is as follows:
Base polymer: poly(2,2,2-trifluoroethylmethacrylate) 2 g (represented by Chemical Formula 1 below) Acid generator: triphenylsulfonium triflate 0.4 g Solvent: diglyme 20 g Chemical Formula 1:
[0091] Modification 2 of Embodiment 6
[0092] Modification 2 of Embodiment 6 is different from Embodiment 6 in the resist material alone, and hence, the resist material alone will be herein described. Specifically, the resist material includes a base polymer in which a fluorine atom is substituted for a hydrogen atom bonded to a side chain of the base polymer, in particular, a hydrogen atom in an ester portion of the acrylic resin. The specific composition of the resist material is as follows:
Base polymer: 2 g poly(1,1,1,3,3,3-hexafluoroisopropylmethacrylate) (represented by Chemical Formula 2 below) Acid generator: triphenylsulfonium triflate 0.4 g Solvent: diglyme 20 g Chemical Formula 2:
[0093] [0093]FIG. 7 shows the relationship between the wavelength of exposing light and transmittance obtained when resist films each with a thickness of 0.1 am are respectively formed by using the resist materials of Modifications 1 and 2 of Embodiment 6 and a conventional resist material.
[0094] It is understood from FIG. 7 that transmittance of 40% or more is attained against a wavelength of a 157 nm band (F 2 laser beam) according to Modifications 1 and 2 of Embodiment 6. In using the conventional resist material, the transmittance against the wavelength of a 157 nm band (F 2 laser beam) is approximately 20%.
[0095] Embodiment 7
[0096] In a base polymer of a resist material used in a pattern formation method of Embodiment 7, an alkyl group such as a methyl group is included, and a fluorine atom is substituted for a hydrogen atom in a protecting group of the base polymer. The specific composition of the resist material is as follows:
Base polymer: 2 g poly((2,2,2-trifluoroethylmethacrylate) - (2-methyl-2-adamantylmethacrylate) (represented by Chemical Formula 3 below) Acid generator: triphenylsulfonium triflate 0.4 g Solvent: diglyme 20 g Chemical Formula 3:
[0097] First, as is shown in FIG. 2( a ), the resist material having the aforementioned composition is applied by spin coating on a semiconductor substrate 10 , thereby forming a resist film 11 . Then, as is shown in FIG. 2 ( b ), the resist film 11 is irradiated with a F 2 laser beam 13 with a wavelength of a 157 nm band through a mask 12 for pattern exposure. In this manner, an acid is generated from the acid generator in an exposed portion 11 a of the resist film 11 while no acid is generated in an unexposed portion 11 b of the resist film 11 .
[0098] Next, as is shown in FIG. 2 ( c ), the semiconductor substrate 10 is heated. Although the base polymer is alkali-refractory, it decomposes when heated in the presence of an acid, and hence, the exposed portion 11 a of the resist film 11 becomes soluble in an alkaline aqueous solution.
[0099] Thereafter, the resist film 11 is developed with an alkaline developer such as a 2.38 wt % tetramethylammonium hydroxide developer. Since the exposed portion 11 a of the resist film 11 is dissolved in the developer, the unexposed portion 11 b of the resist film 11 is formed into a resist pattern 14 as is shown in FIG. 2( d ).
[0100] In the base polymer of Embodiment 7, a methyl group is included, and a fluorine atom is substituted for a hydrogen atom in the protecting group of the base polymer, and hence, the absorbing property against light of a short wavelength is decreased. Therefore, the absorbing property against light of a wavelength of a 1 nm through 180 nm band is decreased. Accordingly, the transmittance against the exposing light of a wavelength of a 1 nm through 180 nm band is increased, and hence, the exposing light can sufficiently reach the bottom of the resist film 11 . As a result, the resist pattern can be formed in a good sectional shape with a line width of 0.07 μm.
[0101] Examples of the protecting group of the base polymer of Embodiment 7 are a t-butyl group, a 1-ethoxyethyl group and a t-butyloxycarbonyl group substituted by a halogen atom, a cyano group, a nitro group, an alkoxy group, an amino group, an alkyl group, a trifluoromethyl group or a mercapto group.
[0102] Embodiment 8
[0103] In a base polymer of a resist material used in a pattern formation method of Embodiment 8, fluorine atoms are substituted for part of hydrogen atoms bonded to a benzene ring of poly(vinyl phenol), and an agent for inhibiting dissolution of a base polymer (hereinafter referred to as a dissolution inhibiting agent) in which fluorine atoms are substituted for part of hydrogen atoms bonded to a benzene ring is included in the resist material. The specific composition of the resist material is as follows:
Base polymer: 1 g poly(o,o-difluoro-p-hydroxystyrene-co-o,o-difluoro-p- trifluoromethoxystyrene) Dissolution inhibiting agent: 0.4 g bis(p-(t-butoxycarbonyloxy)-m,m-difluorophenyl)methane Acid generator: triphenylsulfonium triflate 0.01 g Solvent: ethylethoxypropyonate 4 g
[0104] First, as is shown in FIG. 2( a ), the resist material having the aforementioned composition is applied by spin coating on a semiconductor substrate 10 , thereby forming a resist film 11 . Then, as is shown in FIG. 2( b ), the resist film 11 is irradiated with a F 2 laser beam 13 with a wavelength of a 157 nm band through a mask 12 for pattern exposure. In this manner, an acid is generated from the acid generator in an exposed portion 11 a of the resist film 11 while no acid is generated in an unexposed portion 11 b of the resist film 11 .
[0105] Although the base polymer is alkali-soluble, the resist film 11 is alkali-refractory due to the function of the dissolution inhibiting agent. Therefore, when the semiconductor substrate 10 is heated as is shown in FIG. 2( c ), the dissolution inhibiting agent is heated in the presence of an acid, and hence, it decomposes. As a result, the exposed portion 11 a of the resist film 11 becomes soluble in an alkaline aqueous solution.
[0106] Thereafter, the resist film 11 is developed with an alkaline developer. Since the exposed portion 11 a of the resist film 11 is dissolved in the developer, the unexposed portion 11 b of the resist film 11 is formed into a resist pattern 14 as is shown in FIG. 2( d ).
[0107] In the base polymer and the dissolution inhibiting agent of Embodiment 8, fluorine atoms are substituted for part of hydrogen atoms bonded to the benzene ring, and hence, the peak of the light absorption wavelength determined by the benzene ring is shifted toward a longer wavelength. Therefore, the absorbing property against light of a wavelength of a 1 nm through 180 nm band is decreased. Accordingly, the transmittance against the exposing light of a wavelength of a 1 nm through 180 nm band is increased, and hence, the exposing light can sufficiently reach the bottom of the resist film 11 . As a result, the resist pattern can be formed in a good sectional shape with a line width of 0.1 μm.
[0108] Modification of Embodiment 8
[0109] Modification of Embodiment 8 is different from Embodiment 8 in the resist material alone, and hence, the resist material alone will be herein described. Specifically, the resist material includes a base polymer in which amino groups are substituted for part of hydrogen atoms bonded to a benzene ring of poly(vinyl phenol), and further includes the dissolution inhibiting agent including a cyano group.
Base polymer: 1 g poly(o-amino-p-hydroxystyrene-co-o-amino-p- methoxystyrene) Dissolution inhibiting agent: bis(p-(t-butoxy)-m-cyanophenyl)methane 0.4 g Acid generator: triphenylsulfonium triflate 0.01 g Solvent: ethylethoxypropyonate 4 g
[0110] Embodiment 9
[0111] In a base polymer of a resist material used in a pattern formation method of Embodiment 9, an amino group is bonded to carbon constituting a double bond. The specific composition of the resist material is as follows:
Base polymer: 1 g poly((1-vinyloxy)3-amino-2-cyclohexene-co- vinyloxyethoxyethane) Acid generator: trimethylsulfonium triflate 0.01 g Solvent: 4 g propylene glycol monoethyl ether acetate
[0112] First, as is shown in FIG. 2( a ), the resist material having the aforementioned composition is applied by spin coating on a semiconductor substrate 10 , thereby forming a resist film 11 . Then, as is shown in FIG. 2( b ), the resist film 11 is irradiated with a F 2 laser beam 13 with a wavelength of a 157 nm band through a mask 12 for pattern exposure. In this manner, an acid is generated from the acid generator in an exposed portion 11 a of the resist film 11 while no acid is generated in an unexposed portion 11 b of the resist film 11 .
[0113] Next, as is shown in FIG. 2( c ), the semiconductor substrate 10 is heated. Although the base polymer is alkali-refractory, it decomposes when heated in the presence of an acid, and hence, the exposed portion 11 a of the resist film 11 becomes soluble in an alkaline aqueous solution.
[0114] Thereafter, the resist film 11 is developed with an alkaline developer. Since the exposed portion 11 a of the resist film 11 is dissolved in the developer, the unexposed portion 11 b of the resist film 11 is formed into a resist pattern 14 as is shown in FIG. 2( d ).
[0115] In the base polymer of Embodiment 9, an amino group is bonded to carbon constituting a double bond, and hence, the absorbing property against light of a short wavelength is decreased. Therefore, the absorbing property against light of a wavelength of a 1 nm through 180 nm band is decreased. Accordingly, the transmittance against the exposing light of a wavelength of a 1 nm through 180 nm band is increased, and hence, the exposing light can sufficiently reach the bottom of the resist film 11 . As a result, the resist pattern can be formed in a good sectional shape with a line width of 0.1 μm.
[0116] Embodiment 10
[0117] In a base polymer of a resist material used in a pattern formation method of Embodiment 10, fluorine atoms are substituted for part of hydrogen atoms bonded to a benzene ring of poly(vinyl phenol). The specific composition of the resist material is described below. It is noted that a negative resist pattern is formed in Embodiment 10 while a positive resist pattern is formed in each of Embodiments 1 through 9.
Base polymer: 1 g poly(o,o-difluoro-p-hydroxystyrene-co-o,o-difluoro-p- trifluoromethoxystyrene) Crosslinking agent: 0.3 g 2,4,6-tri(N,N-diethoxymethylamino)-1,3,5-triazine Acid generator: triphenylsulfonium triflate 0.01 g Solvent: ethyl lactate 4 g
[0118] First, as is shown in FIG. 3( a ), the resist material having the aforementioned composition is applied by spin coating on a semiconductor substrate 20 , thereby forming a resist film 21 . Then, as is shown in FIG. 3( b ), the resist film 21 is irradiated with a F 2 laser beam 23 with a wavelength of a 157 nm band through a mask 22 for pattern exposure. In this manner, an acid is generated from the acid generator in an exposed portion 21 a of the resist film 21 while no acid is generated in an unexposed portion 21 b of the resist film 21 .
[0119] Next, as is shown in FIG. 3( c ), the semiconductor substrate 20 is heated. Although the base polymer is alkali-soluble, crosslinkage is caused by the function of the crosslinking agent when it is heated in the presence of an acid, and hence, the exposed portion 21 a of the resist film 21 becomes alkali-refractory.
[0120] Thereafter, the resist film 21 is developed with an alkaline developer. Since the unexposed portion 21 b of the resist film 21 is dissolved in the developer, the exposed portion 21 a of the resist film 21 is formed into a resist pattern 24 as is shown in FIG. 3( d ).
[0121] In the base polymer of Embodiment 10, fluorine atoms are substituted for part of hydrogen atoms bonded to the benzene ring of poly(vinyl phenol), and hence, the peak of the light absorption wavelength determined by the benzene ring is shifted toward a longer wavelength. Therefore, the absorbing property against light of a wavelength of a 1 nm through 180 nm band is decreased. Accordingly, the transmittance against the exposing light of a wavelength of a 1 nm through 180 nm band is increased, and hence, the exposing light can sufficiently reach the bottom of the resist film 21 . As a result, the resist pattern can be formed in a good sectional shape with a line width of 0.1 μm.
[0122] Modification of Embodiment 10
[0123] Modification of Embodiment 10 is different from Embodiment 10 in the resist material alone, and hence, the resist material alone will be herein described. Specifically, the resist material includes a base polymer in which mercapto groups are substituted for part of hydrogen atoms bonded to a benzene ring of poly(vinyl phenol), and further includes a crosslinking agent including an alkoxy group.
Base polymer: 1 g poly(p-hydroxystyrene-co-o-mercapto-p methoxystyrene) Crosslinking agent: 0.3 g 1,3-dimethoxy-1,2,3-pentanetrioltriglycidyl ether Acid generator: triphenylsulfonium triflate 0.01 g Solvent: ethyl lactate 4 g
[0124] Embodiment 11
[0125] In a pattern formation method of Embodiment 11, a base polymer of a resist material includes a fluorine atom, and a water-soluble polymer film including a fluorine atom is deposited on a resist film. In Embodiment 11, a positive resist pattern is formed. The specific composition of the resist material is as follows:
Base polymer: 2 g poly((2-methyl-2-adamantylmethacrylate) (30 mol %)- tri(trifluoromethyl)methylmethacrylate) (30 mol %)- (methylmethacrylate) (30 mol %)- (methacrylic acid) (10 mol %) Acid generator: triphenylsulfonium triflate 0.4 g Solvent: diglyme 20 g
[0126] First, as is shown in FIG. 4( a ), the resist material having the aforementioned composition is applied by spin coating on a semiconductor substrate 30 , thereby forming a resist film 31 with a thickness of, for example, 0.5 μm. Then, as is shown in FIG. 4( b ), a water-soluble polymer film 32 made from a water-soluble polymer including a fluorine atom is deposited on the resist film 31 .
[0127] Examples of the water-soluble polymer are polyacrylic acid, poly(vinyl alcohol), poly(vinyl pyrrolidone) or polystyrene sulfonic acid in which halogen atoms such as a fluorine atom, cyano groups, nitro groups, alkoxy groups, amino groups, alkyl groups, trifluoromethyl groups or mercapto groups are substituted for all or part of hydrogen atoms; and polymers represented by Chemical Formulas 4 through 7 below, which do not limit the invention.
[0128] Next, as is shown in FIG. 4( c ), the resist film 31 is irradiated with a F 2 laser beam 34 with a wavelength of a 157 nm band through a mask 33 for pattern exposure. In this manner, an acid is generated from the acid generator in an exposed portion 31 a of the resist film 31 while no acid is generated in an unexposed portion 31 b of the resist film 31 .
[0129] Then, as is shown in FIG. 4( d ), the semiconductor substrate 30 is heated. Although the base polymer is alkali-refractory, it decomposes when heated in the presence of an acid, and hence, the exposed portion 31 a of the resist film 31 becomes soluble in an alkaline aqueous solution.
[0130] Thereafter, the water-soluble polymer film 32 is removed and the resist film 31 is developed with a 2.38 wt % tetramethylammonium hydroxide developer. Thus, the unexposed portion 31 b of the resist film 31 is formed into a resist pattern 35 as is shown in FIG. 4( e ).
[0131] In Embodiment 11, since both the base polymer of the resist material and the water-soluble polymer film 32 include a fluorine atom, the exposing light can definitely reach the bottom of the resist film 31 . As a result, the resist pattern 35 can be formed in a good pattern shape.
[0132] Embodiment 12
[0133] In a pattern formation method of Embodiment 12, a base polymer of a resist material includes a fluorine atom, and a water-soluble polymer film made from a compound including a fluorine atom and a water-soluble polymer is deposited on a resist film. Also in Embodiment 12, a positive resist pattern is formed. The specific composition of the resist material is as follows:
Base polymer: 2 g poly((2-methyl-2-adamantylmethacrylate) (30 mol %)- tri(trifluoromethyl)methylmethacrylate) (30 mol %)- (methylmethacrylate) (30 mol %)- (methacrylic acid) (10 mol %) Acid generator: triphenylsulfonium triflate 0.4 g Solvent: diglyme 20 g
[0134] First, as is shown in FIG. 4( a ), the resist material having the aforementioned composition is applied by spin coating on a semiconductor substrate 30 , thereby forming a resist film 31 with a thickness of, for example, 0.5 μm. Then, as is shown in FIG. 4( b ), a water-soluble polymer film 32 made from a compound including a fluorine atom and a water-soluble polymer is deposited on the resist film 31 .
[0135] Examples of the compound including a fluorine atom are trifluoroacetic acid, trifluoromethylsulfonic acid and a surfactant including fluorine, which do not limit the invention.
[0136] Also, examples of the water-soluble polymer are polyacrylic acid, poly(vinyl alcohol), poly(vinyl pyrrolidone) and polystyrenesulfonic acid, which do not limit the invention.
[0137] Next, as is shown in FIG. 4( c ), the resist film 31 is irradiated with a F 2 laser beam 34 with a wavelength of a 157 nm band through a mask 33 for pattern exposure. In this manner, an acid is generated from the acid generator in an exposed portion 31 a of the resist film 31 while no acid is generated in an unexposed portion 31 b of the resist film 31 .
[0138] In this case, since the water-soluble polymer film 32 includes a fluorine atom, the water-soluble polymer film 32 guides merely light with high intensity to the resist film 31 .
[0139] Then, as is shown in FIG. 4( d ), the semiconductor substrate 30 is heated. Although the base polymer is alkali-refractory, it decomposes when heated in the presence of an acid, and hence, the exposed portion 31 a of the resist film 31 becomes soluble in an alkaline aqueous solution.
[0140] Thereafter, the water-soluble polymer film 32 is removed and the resist film 31 is developed with a 2.38 wt % tetramethylammonium hydroxide developer. Thus, the unexposed portion 31 b of the resist film 31 is formed into a resist pattern 35 as is shown in FIG. 4( e ).
[0141] In Embodiment 12, since both the base polymer of the resist material and the water-soluble polymer film 32 include a fluorine atom, the exposing light can definitely reach the bottom of the resist film 31 . As a result, the resist pattern 35 can be formed in a good pattern shape.
[0142] Embodiment 13
[0143] In a base polymer of a resist material used in a pattern formation method of Embodiment 13, fluorine atoms are substituted for part of hydrogen atoms bonded to a benzene ring of poly(vinyl phenol). It is noted that a novolak resin, that is, a general resist material, is used for forming a negative resist pattern in Embodiment 13 while a chemically amplified resist is used in each of Embodiments 1 through 12. The specific composition of the resist material is as follows:
Base polymer: 1 g poly(o,o-difluoro-p-hydroxy-α-fluorostyrene- co-o,o-difluoro-p-trifluoromethoxy-α- fluorostyrene) Solvent: 4 g propylene glycol monoethyl ether acetate
[0144] First, as is shown in FIG. 5( a ), the resist material having the aforementioned composition is applied by spin coating on a semiconductor substrate 40 , thereby forming a resist film 41 . Then, as is shown in FIG. 5( b ), the resist film 41 is irradiated with a F 2 laser beam 43 with a wavelength of a 157 nm band through a mask 42 for pattern exposure. As a result, although the resist material is alkali-soluble, an exposed portion 41 a of the resist film 41 becomes refractory in an alkaline aqueous solution through a crosslinking reaction while an unexposed portion 41 b of the resist film 41 remains alkali-soluble.
[0145] Next, the resist film 41 is developed with an alkaline developer. Since the unexposed portion 41 b of the resist film 41 is dissolved in the developer, the exposed portion 41 a of the resist film 41 is formed into a resist pattern 44 as is shown in FIG. 5( c ).
[0146] In the base polymer of Embodiment 13, fluorine atoms are substituted for part of hydrogen atoms bonded to a benzene ring, and hence, the light absorption wavelength determined by the benzene ring is shifted toward a longer wavelength. Therefore, the absorbing property against light of a wavelength of a 1 nm through 180 nm band is decreased. Accordingly, the transmittance against the exposing light of a wavelength of a 1 nm through 180 nm band is increased, and hence, the exposing light can sufficiently reach the bottom of the resist film 41 . As a result, the resist pattern can be formed in a good sectional shape with a line width of 0.12 μm.
[0147] Although the F 2 laser beam with a wavelength of a 157 nm band is used as the exposing light in each of Embodiments 1 through 13 and Modifications thereof, the same effect can be attained by using a Xe 2 laser beam (with a wavelength of a 172 nm band), a Kr 2 laser beam (with a wavelength of a 146 nm band), an ArKr laser beam (with a wavelength of a 134 nm band), an Ar 2 laser beam (with a wavelength of a 126 nm band) or a soft X-ray beam (with a wavelength of a 13, 11 or 5 nm band) instead.
[0148] Furthermore, in each of Embodiments 1 through 12 and Modifications thereof, any of onium salts such as a sulfonium salt and a iodonium salt, sulfonic esters, diazodisulfonylmethanes and ketosulfone compounds can be appropriately used as the acid generator.
[0149] Moreover, in each of Embodiments 1 through 12 and Modifications thereof, the resist material can include a basic compound such as amine or an additive such as a surfactant, if necessary.
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A resist film is formed by applying, on a semiconductor substrate, a resist material including at least one atom or group selected from the group consisting of a halogen atom, a cyano group, a nitro group, an alkoxy group, an amino group, an alkyl group, a trifluoromethyl group and a mercapto group. The resist film is irradiated with exposing light of a wavelength of a 1 nm through 180 nm band for pattern exposure, and the resist film is developed after the pattern exposure, so as to form a resist pattern.
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BACKGROUND
[0001] This invention relates generally to the formation of quantum well transistors.
[0002] A quantum well is a potential well that confines particles in a dimension forcing them to occupy a planar region. A first material, sandwiched between two layers of a material with a wider band gap than the first material, may form a quantum well. Quantum well or high electron mobility transistors (HEMTs) are field effect transistors with a junction between two materials with different band gaps as the channel. The junction may exhibit very low resistance or high electron mobility. A voltage applied to the gate may alter the conductivity of the junction.
[0003] Quantum well transistors may be prone to high gate leakage and parasitic series resistance. Particularly, quantum well transistors using elements from columns III through V of the periodic table may be prone to such problems. Examples of such materials include indium gallium arsenide/indium aluminum arsenide and indium antimony/aluminum indium antimony.
[0004] In current state of the art quantum well transistors, a direct Schottky metal gate may be deposited on a barrier layer to form the Schottky junction which may be prone to high gate leakage. Also, the source and drain regions may be patterned and source and drain contact metallization completed before gate patterning. The gate patterning is done as the last step in the process, which may result in non-self-aligned source drain regions. Such non-self-aligned source drain regions may be prone to parasitic series resistance. Devices with parasitic series resistance may exhibit poor performance.
[0005] Thus, there is a need for better ways to make quantum well transistors.
BRIEF DESCRIPTION OF THE DRAWINGS
[0006] FIG. 1 is an enlarged, cross-sectional view of one embodiment of the present invention;
[0007] FIG. 2 is an enlarged, cross-sectional view of the embodiment shown in FIG. 1 at an early stage of manufacture in accordance with one embodiment of the present invention;
[0008] FIG. 3 is an enlarged, cross-sectional view of the embodiment shown in FIG. 2 after subsequent processing in accordance with one embodiment of the present invention;
[0009] FIG. 4 is an enlarged, cross-sectional view corresponding to FIG. 3 after subsequent processing in accordance with one embodiment of the present invention;
[0010] FIG. 5 is an enlarged, cross-sectional view corresponding to FIG. 4 after subsequent processing in accordance with one embodiment of the present invention;
[0011] FIG. 6 is an enlarged, cross-sectional view corresponding to FIG. 5 after subsequent processing in accordance with one embodiment of the present invention;
[0012] FIG. 7 is an enlarged, cross-sectional view corresponding to FIG. 6 after subsequent processing in accordance with one embodiment of the present invention;
[0013] FIG. 8 is an enlarged, cross-sectional view corresponding to FIG. 7 after subsequent processing in accordance with another embodiment of the present invention;
[0014] FIG. 9 is an enlarged, cross-sectional view corresponding to FIG. 8 after subsequent processing in accordance with a depletion mode embodiment of the present invention; and
[0015] FIG. 10 is an enlarged, cross-sectional view corresponding to FIG. 7 after subsequent processing in accordance with an enhancement mode embodiment of the present invention;
DETAILED DESCRIPTION
[0016] Referring to FIGS. 1 and 10 , a depletion ( FIG. 1 ) or enhancement mode ( FIG. 10 ) self-aligned source drain quantum well transistor may be formed with a high dielectric constant dielectric layer 24 and a metal gate electrode 38 that acts as a Schottky gate metal. As used herein “high dielectric constant” refers to dielectrics having dielectric constants of 10 or greater.
[0017] Over a silicon substrate 10 may be an accommodation layer 12 . The accommodation layer 12 may be AlInSb with 15% aluminum in one embodiment. Over a silicon substrate 10 , a germanium layer (not shown) may be included under the layer 12 as well. The accommodation layer 12 functions to accommodate for the lattice mismatch problem and to confine dislocations or defects in that layer 12 .
[0018] Over the accommodation layer 12 may be formed a lower barrier layer 14 in accordance with one embodiment of the present invention. The lower barrier layer 14 may, for example, be formed of aluminum indium antimonide or indium aluminum arsenide, as two examples. The lower barrier layer 14 may be formed of a higher band gap material than the overlying quantum well 16 .
[0019] Over the lower barrier layer 14 is formed the undoped quantum well 16 . In one embodiment, the undoped quantum well 16 may be formed of indium antimonide or indium gallium arsenide, as two examples.
[0020] Next, the upper barrier layer 20 may be formed. The upper barrier layer 20 may be formed of the same or different materials as the lower barrier layer 14 . The upper barrier layer 20 may include a delta doped donor layer 18 . The delta doping may be done using silicon or tellurium, as two examples. The doped donor layer 18 supplies carriers to the quantum well 16 for transport. The doped donor layer 18 is formed by allowing Te or Si dopants to flow into the MBE (Molecular Beam Epitaxy) chamber in a controlled fashion from a solid source.
[0021] Thus, the quantum well 16 is sandwiched between the upper and lower barrier layers 20 and 14 . The upper barrier layer 20 may be an electron supplying layer whose thickness will determine the threshold voltage of the transistor, along with the workfunction of the Schottky metal layer forming the gate electrode 38 .
[0022] The metal gate electrode 38 may be formed over a high dielectric constant dielectric material 26 . The material 26 brackets the metal gate electrode 38 on three sides. The high dielectric constant layer 26 may, in turn, be bracketed by a self-aligned source drain contact metallization 22 and a spacer layer 28 .
[0023] Fabrication of the depletion mode transistor, shown in FIG. 1 , and the enhancement mode transistor of FIG. 10 may begin, as shown in FIG. 2 , by forming the structure up to and including an n+ doped layer 30 . The layer 30 may include an indium antimonide or indium gallium arsenide doped with Te and Si impurities. The layer 30 may be highly doped to later form the source drain regions in the finished transistor.
[0024] The multilayer epitaxial substrate 10 may be grown using molecular beam epitaxy or metal organic chemical vapor deposition, as two examples.
[0025] Referring to FIG. 3 , a dummy gate 32 may be formed over the n+ doped layer 30 in accordance with one embodiment of the present invention. It may be formed after patterning and etch out of nitride, carbide, or oxide films (not shown). Advantageously, these films may be formed by low temperature deposition to preserve the integrity of the epitaxial layer structure. The dummy gate 32 may, for example, be formed of silicon nitride or metal. The dummy gate 32 may be formed by patterning through either lithography and etching, in the case of a silicon nitride dummy gate 32 , or through evaporation and liftoff in the case of a metal gate 32 , such as an aluminum metal dummy gate.
[0026] Referring next to FIG. 4 , low temperature silicon oxide, nitride or carbide spacers 28 may be formed that bracket the dummy gate 32 . The spacers 28 may be formed by a low temperature deposition technique, followed by anisotropic etching.
[0027] Turning next to FIG. 5 , the self-aligned source drain contact metallizations 22 may be formed by electron beam evaporation or reactive sputtering, either followed by a chemical mechanical planarization process, to create self-aligned contacts to the yet to be formed source drain regions in the layer 30 . The source drain contact metallization 22 may, for example, be formed of titanium or gold.
[0028] Then, as shown in FIG. 6 , the dummy gate 32 may be selectively etched out using a wet etch. As a result, an opening 34 is formed. A metal dummy gate removal process may, for example, include a wet etch using phosphoric acid etch. For a nitride dummy gate, hydrochloric acid may be used. For a silicon dioxide dummy gate a hydrofluoric acid etch can be used. The wet etch process is selective to the n+ doped layer 30 .
[0029] Then, as shown in FIG. 7 for a depletion mode device, a selective etch out of the n+ doped layer 30 may be achieved to form an inverted T-shaped opening having wings 36 and a base 34 . Dry or wet etching may be utilized to form the wings 36 . For example, the n+ doped layer 30 is selectively removed using a wet etch process such as citric acid plus peroxide.
[0030] Atomic layer deposition of the high dielectric constant material 26 may be followed by electron beam evaporation or sputtering of a metal gate electrode 38 . The gate electrode 38 may, for example, be platinum, tungsten, palladium, or molybdenum, to mention a few examples. The high dielectric constant dielectric 26 may, for example, be hafnium dioxide or zirconium dioxide, as two examples. A low temperature deposition process may be utilized with an organic precursor (such as alkoxide precursor for hafnium dioxide deposition).
[0031] The structure shown in FIG. 8 may then be subjected to a chemical mechanical polish of the metal gate electrode 38 and the high dielectric constant dielectric 26 to achieve the depletion mode structure shown in FIG. 9 .
[0032] Right after the n+ doped layer 30 etch out to form the opening 34 including wings 36 and base 34 , as shown in FIG. 7 , a further recess etch may be done through the electron supplying barrier layer 20 , stopping just above the delta doped layer 18 to make an enhancement mode device as shown in FIG. 10 . A time drive etch (not shown in FIG. 7 ) may partially recess into the electron supplying barrier layer 20 in FIG. 7 and under the spacers 28 , to increase the threshold voltage of the transistor and to form an enhancement mode device.
[0033] The device layer structure survives the high dielectric constant deposition process. This may be followed by sputter deposition or electron beam deposition of the Schottky gate electrode 38 . The gate electrode 38 workfunction may be chosen to be as high as possible to create an enhancement mode device.
[0034] Some embodiments of the present invention may achieve lower gate leakage from the incorporation of a high dielectric constant dielectric 20 in between the Schottky gate metal of the electrode 38 and the semiconductor barrier layer 20 . Lower parasitic series resistance may result, in some embodiments, from the highly doped source drain region self-aligned to the gate. In some embodiments, the recess etch of the electron supplying barrier layer 20 to the desired thickness forms an enhancement mode quantum well field effect transistor.
[0035] While the present invention has been described with respect to a limited number of embodiments, those skilled in the art will appreciate numerous modifications and variations therefrom. It is intended that the appended claims cover all such modifications and variations as fall within the true spirit and scope of this present invention.
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A quantum well transistor or high electron mobility transistor may be formed using a replacement metal gate process. A dummy gate electrode may be used to define sidewall spacers and source drain contact metallizations. The dummy gate electrode may be removed and the remaining structure used as a mask to etch a doped layer to form sources and drains self-aligned to said opening. A high dielectric constant material may coat the sides of said opening and then a metal gate electrode may be deposited. As a result, the sources and drains are self-aligned to the metal gate electrode. In addition, the metal gate electrode is isolated from an underlying barrier layer by the high dielectric constant material.
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INVENTION BACKGROUND
Traditionally, a subsea christmas tree provides pressure control of a well completion system that comprises a centrally located well bore and a surrounding annulus conduit. The centrally located well bore is typically used for the extraction of reservoir hydrocarbons and is referred to as the production bore. The annulus conduit is typically used to service the well, for example allowing the circulation of fluids during well start up and shut down. During the production phase of the well, the annulus is often redundant and is monitored for pressure build up indicating a possible production tubing or packer leak from the production bore. Some wells employ the annulus for gas lift. Gas is pumped down the annulus and enters the production bore at specific locations thereby reducing the density and viscosity of the produced fluids. Electrical, optical and hydraulic service lines are also typically routed through the annulus for powering and control of downhole equipment such as valves and pumps, or for data transmission from downhole sensors. Chemical injection lines are likewise routed through the annulus.
Recent developments in expandable casing technology and reeled tubular technology dictate completion designs having decreased diameter well casing tubulars located external to the production tubing. The radial gaps between the tubulars are likewise reduced.
SUMMARY OF THE INVENTION
The present invention enables still further benefits to be gained from expandable casing technology. According to the invention, there is provided a completion system comprising a christmas tree mounted on a wellhead housing, a tubing hanger landed in the tree or wellhead housing, the wellhead housing being mounted on a casing string and a tubing string being suspended from the tubing hanger within the casing string; characterised in that, in use, the annulus defined between the tubing and the casing serves as a production bore and the tubing serves as a well service conduit; a second tubing string being expanded into sealing engagement with the casing string over at least a portion of their lengths. A second or outer tubing string surrounding that suspended from the tubing hanger may therefore be expanded to contact the production casing so that a seal is effected between these two tubulars, thereby eliminating the annulus conduit. The annulus conduit may only be absent at the base of the well in the case of a tapered well construction but uniform diameter, non-tapering wells are also possible in which the annulus is totally eliminated.
In this circumstance, it is no longer possible to circulate fluids in the well via the annulus and the central tubing string suspended from the tubing hanger performs the function that the annulus traditionally performs. The annulus conduit defined between the two tubing strings is now used for production. This has a significant impact on the configuration of the completion equipment, especially the tree. Further preferred features and advantages of the invention are in the dependent claims and the following description of preferred embodiments, made with reference to the drawings.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a diagrammatic representation of a first completion system embodying the invention, shown during installation/testing;
FIG. 2 corresponds to FIG. 1 but shows the system in production mode;
FIG. 3 diagrammatically represents a tubing hanger such as may be used in the system of FIG. 1 ;
FIGS. 4 and 5 show an alternative tubing hangers;
FIGS. 6 , 8 , 10 and 12 are diagrams of second, third, fourth and fifth embodiments of the completion system respectively, all shown during installation/testing;
FIGS. 7 , 9 , 11 and 13 correspond to FIGS. 6 , 8 , 10 and 12 respectively, but show the system in production mode;
FIG. 14 shows a modification of the embodiment of FIG. 13 ;
FIG. 15 is a diagram of a first casing program that may be used in conjunction with the completion system of the invention;
FIG. 16 corresponds to FIG. 15 but diagrammatically indicates a liner, an outer tubing string and completion riser run into the casing;
FIG. 17 is a diagram of the interface between the tree, wellhead housing and outer tubing hanger of the completion system of FIG. 16 ;
FIG. 18 corresponds to FIG. 17 but diagrammatically indicates a central circulation tubing string and liner top isolation valve installed in the well;
FIG. 19 is a diagrammatic cross-section through the central circulation tubing;
FIG. 20 is a diagram of a second casing program that may be used in conjunction with the completion system of the invention;
FIG. 21 corresponds to FIG. 20 but diagrammatically indicates a liner and outer tubing run into the well;
FIGS. 22 and 23 show tubing expansion operations;
FIG. 24 is a diagram of the interface between the tree, wellhead housing and outer tubing of the completion system of FIG. 21 ;
FIGS. 25 to 27 show modifications of FIG. 24 ;
FIG. 28 is a diagram of a third casing program that may be used in conjunction with the completion system of the invention;
FIG. 29 corresponds to FIG. 28 but diagrammatically indicates a liner, production casing and outer tubing run into the well, and
FIG. 30 is a diagram of the interface between the tree, wellhead housing and outer tubing hanger of the completion system of FIG. 22 .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
The preferred completion system includes a subsea christmas tree configuration that will allow the installation of a centrally located service conduit. The preferred well, construction also comprises the following components that are typically used in completions and accordingly the subsea tree design provides the appropriate interfacing equipment:
SCSSV or functional equivalent Downhole chemical injection Gas lift mandrels Downhole instrumentation, e.g. pressure and temperature gauges
The central service conduit provided by a central coiled tubing string is preferably replaceable with minimum impact on the installed second or outer production tubing and subsea christmas tree equipment. The outer tubing string is terminated at the wellhead housing (either with or without a tubing hanger) and the tree seals to the wellhead housing with a seal stab.
Referring to FIG. 1 , coiled tubing 14 is suspended from a coiled tubing hanger 12 in a horizontal christmas tree 10 . The tree 10 is locked and sealed to a wellhead housing 11 . No SCSSV is included in the system. For installation, the coiled tubing hanger 12 has a lock profile 16 by which it is attached to an installation test tool 18 . A central circulation/service valve 20 is situated in the coiled tubing hanger 12 for controlling fluid flows from/to the coiled tubing 14 . The coiled tubing hanger 12 is landed in a vertically extending through bore 15 in the tree 10 . The tubing hanger 12 is sealed and locked to the tree as schematically indicated, by annular seal 22 and lock profile 24 . Remote wet mate couplers 26 allow downhole service and control lines 28 to be connected to corresponding lines 30 in the installation test tool 18 and its installation string 32 . The outside diameters of the coiled tubing hanger 12 , installation test tool 18 and installation string 32 are compatible with the drift of a monobore completions riser which has, for example, a bore diameter of 17.1 mm (6.75″).
A production conduit 34 intersects with the through bore 15 below the tubing hanger seal 22 . A production master valve 36 and a production wing valve 38 are provided in the production conduit 34 . A pressure cap 40 is optionally installed on a wing outlet 42 of the tree 10 at the stage of installation and subsequent flow test. For flow testing, a production bypass conduit 44 containing a valve 46 extends between the production conduit 34 to the through bore 15 above the tubing hanger seal 22 . A service/circulation conduit 48 intersects with the through bore 15 above the tubing hanger seal 22 . The conduit 48 contains a valve 50 of equivalent function to the annulus wing valve of a “standard” horizontal tree. However, rather than communicating with a production tubing/production casing annulus as is conventional, the service/circulation conduit 48 is connected to the upper end of the coiled tubing 14 . A crossover conduit 45 containing a crossover valve 47 connects the bypass conduit 44 (and/or the production conduit 34 between the valves 36 , 38 ) to the circulation/service conduit 48 .
The installation test tool 18 is connected between the coiled tubing hanger 12 and the installation string 32 . Upper and lower seals 52 , 54 seal a lower end of the installation test tool 18 within the tree through bore 15 . A conduit 56 in the installation test tool 18 has a side outlet positioned between the seals 52 , 54 for communication with the production bypass conduit 44 , and an upper end in communication with a riser conduit 58 in the installation string 32 . During flow testing, production fluid may therefore be led to the surface rig or vessel through the installation test tool interior and the riser conduit 58 .
The lower end of the installation test tool 18 also has a central bore 60 in communication with the coiled tubing interior via the central circulation/service valve 20 . A side outlet 61 leads from the bore 60 to the circulation/service conduit 48 . A workover conduit 62 containing a workover valve 64 extends from the circulation/service conduit 48 to the tree through bore 15 at a point above the installation test tool upper seal 52 . The other end of the installation test tool 18 comprises an upwardly extending spool 66 through which runs the conduit 56 . A BOP 68 is attached to the upper end of the tree 10 . Pipe rams 70 in the BOP 68 can be closed and sealed about the installation test tool spool 66 , thereby sealingly connecting the workover conduit 62 to a choke/kill line 72 of the BOP.
The installation test tool also allows controls to be hooked up to the down-hole lines 28 and for operation of the circulation/service valve 20 in the coiled tubing hanger 12 . Besides the remote subsea mateable couplers 26 to the top of the coiled tubing hanger 12 , the installation test tool 18 also includes further remote subsea mateable couplers 74 to the base of the installation string 32 .
The installation string 32 is latched and sealed to the top of the installation test tool 18 by a remotely operable connector 76 providing emergency disconnect capability. A monobore completions riser 78 is connected to the upper end of the BOP 68 by a lower marine riser package 80 which also provides for emergency disconnection. When disconnected, any fluids present in the riser conduit 58 are retained by a valve 82 . The couplers 74 connect the control lines 30 in the installation test tool 18 to a controls umbilical 84 attached to the installation string 32 .
FIG. 2 shows the tree in production mode. An internal tree cap 86 is installed through the BOP 68 in place of the installation test tool 18 and installation string 32 . The BOP 68 is then removed. The tree cap 86 locks and seals to the tree bore 15 above the production conduit 34 intersection as schematically illustrated by locking profile 88 and seal 90 . Remote subsea mateable couplers 26 are again provided for hook up of control lines to the central circulation/service valve 20 in the coiled tubing hanger 12 and to the downhole lines 28 . A controls cap 92 with remote wet mate couplers 94 connects the control lines to a jumper 96 . The central bore 60 and side outlet of the installation test tool are reproduced in the tree cap 86 to provide fluid communication between the coiled tubing interior and the circulation/service conduit 48 .
The completion system illustrated in FIGS. 1 and 2 satisfies accepted double barrier pressure containment philosophy/industry practice. It provides communication to multiple down-hole electrical and hydraulic service lines, either via a controls umbilical run with the installation string, or via a controls cap and jumper in production mode. A central coiled tubing string 14 is suspended in the well, to provide a means of well circulation for well startup and well kill. It also provides a means for readily installing or removing (eg for servicing and repair) downhole equipment such as valves, pumps, gas lift and chemical injection mandrels and downhole instrumentation. This can be installed/replaced without disturbing the outer production tubing and tree.
The central coiled tubing string 14 is suspended within an outer tubing string 98 which is expanded into sealing contact with surrounding production casing 100 and the wellhead housing 11 . The need for tubing hangers and packers may thus be eliminated. If a tubing hanger is used to suspend the outer tubing string 98 which has its lower end expanded into contact with the production casing, the outer tubing hanger is landed in the wellhead 11 because the outer tubing 98 is permanently attached to the other well tubulars and cannot be retrieved. Landing the outer tubing hanger in the tree 10 would therefore prevent (or at least make difficult) the recovery of the tree. If tubing corrosion occurs, a new (thin wall) liner tubing can be expanded into place inside the old outer tubing.
The use of expandable well tubulars also results in a more gradually tapering, or even uniform diameter, well. Thus the upper tubulars and completion equipment are of reduced size and weight compared to conventional wells of equivalent depth, giving materials savings and reduced operational costs. The marine riser system/BOP stack used at installation only needs a bore similar to a completions riser. Therefore it is very similar to a lightweight intervention system. Faster drill penetration rates can be achieved and the use of lower cost vessels with lower lift capacity is made possible.
Flow tests may be conducted via the installation string and workover access is provided via the coiled tubing string. The tree has a similar cost and complexity to known horizontal trees. No subsea test tree is needed during installation and workover. There is potential to adapt the system for a dual zone completion, for the use of ESP's, or for downhole separation. The effective production tubing size can be reduced as the well matures, by increasing the diameter of the coiled tubing, or a velocity string can be fitted. The completion system offers improved control of well circulation via the subsea tree for well kill or gas lift applications.
FIGS. 3–5 illustrate various alternatives for the coiled tubing hanger configuration. FIG. 3 shows a single body coiled tubing hanger 12 with an integral ball valve 20 and hydraulic actuator. Down hole control lines 102 pass through the hanger body and are connected to control lines 104 external to the coiled tubing 14 via couplers 106 . The down hole controls lines are therefore exposed to produced fluids and mechanical damage during the trip in the hole. The remote mateable couplers 26 must be made very small.
FIG. 4 shows a single, multi-pin, self orienting subsea mateable connector 108 instead of the multiple connectors 26 . This system is particularly suitable if the down hole lines 104 are all of the same type, e.g electrical, optical or hydraulic. It is less suitable if there is a combination of different line types.
FIG. 5 shows a split hanger arrangement in which the coiled tubing hanger comprises two separable parts 12 a , 12 b , joined by a seal stab 110 . The lower part 12 b is prefabricated as part of the coiled tubing string and the service line couplers 112 are factory tested. The lower part 12 b is assembled to the upper part 12 a at the drill floor. This design may have multiple single-pin subsea mateable couplers as shown, or a multi-pin connector similar to 108 , FIG. 4 .
FIG. 6 shows a modification of the system of FIG. 1 , in which the coiled tubing hanger 12 has a blind top, i.e. no vertical through bore is provided. Comparing with the FIG. 1 embodiment, in FIG. 6 the central circulation/service valve 20 has been moved from the coiled tubing hanger 12 to the circulation/service conduit 48 in the tree 10 . The workover conduit 62 still joins the central circulation/service conduit 48 between the valve 20 and the wing valve 50 . The lower seal 54 on the installation test tool 18 has been eliminated and an additional upper seal 114 provided on the coiled tubing hanger 12 . A side outlet 116 in the tubing hanger 12 , analogous to the installation test tool side outlet 61 in FIG. 1 , communicates with the circulation/service conduit 48 , between the tubing hanger upper and lower seals 114 , 22 . In other respects, the FIG. 6 arrangement is structurally and functionally similar to that of FIG. 1 .
FIG. 7 shows the system of FIG. 6 in production mode. It is analogous to FIG. 2 , but having a simplified internal tree cap 86 , as the bore 60 and side outlet 61 are eliminated. A controls cap 92 and a controls jumper 96 are again provided.
FIG. 8 shows a third embodiment, similar to FIG. 6 , except that a second production bypass valve 43 is provided in the production bypass conduit 44 , in series with the valve 46 . This enables the tree cap 86 to be eliminated in production mode ( FIG. 9 ), as the valve 43 can serve as a second pressure barrier in series with the valve 46 , when the production master valve 36 is open. If desired, a secondary lockdown device 118 can be provided for the coiled tubing hanger 12 in production mode. The controls cap 92 and couplers 94 interface directly with the coiled tubing hanger 12 . The embodiment of FIGS. 1 and 2 may be modified in similar manner.
FIG. 10 shows a further modification of the FIG. 6 embodiment. The production bypass conduit 44 and bypass valve 46 have been eliminated, likewise the side outlet in the installation test tool 18 below the seal 52 . Instead, the coiled tubing hanger 12 is provided with flow by slots or a flow by conduit 120 extending from the annulus defined between the tubing strings 14 , 98 below the tubing hanger 12 , to the tree through bore 15 above the tubing hanger 12 . The installation test tool 18 no longer interfaces with the tubing hanger lock profile 16 . Instead, a separate tubing hanger running tool (not shown) is used to install the tubing hanger 12 . Upper and lower swab valves 122 , 124 (e.g. large diameter gate valves) are provided in the tree through bore 15 between the installation test tool 18 and the coiled tubing hanger 12 . In production mode ( FIG. 11 ) these swab valves are closed to provide a double pressure barrier, so that no tree cap is needed. The workover conduit 62 extends from the circulation/service conduit, to the through bore 15 above the installation test tool lower seal 52 , for fluid communication with BOP choke/kill lines 72 , as previously described. Hook up to the downhole service lines 28 is by means of horizontal penetrators in the tree 10 , which interface with the coiled tubing hanger 12 . The coiled tubing hanger 12 is effectively pressure balanced and theoretically needs no lock down. The lower end of the coiled tubing string 14 is not fixed so thermal expansion does not provide an upthrust. Notional lock down is provided by the horizontal penetrators 126 from the tree 10 .
FIG. 12 shows a modification of the FIG. 10 embodiment, for which the installation process is similar to a conventional christmas tree, in that a BOP stack is not used on the tree. The BOP stack and marine riser are removed from the wellhead 10 prior to tree installation and a lower riser package 128 , emergency disconnect package 130 and an open water riser 132 are used for the coiled tubing hanger installation and flow test. A sealed connection interface 134 is provided for coupling the workover conduit 62 in the tree 10 to a port 136 in the lower riser package 128 , of equivalent function to a conventional lower riser package annulus port. An installation test tool is not required for installing and flow testing the completion. The lower riser package 128 /emergency disconnect package 130 system may have a controls umbilical 142 , for example connectable to the tree 10 via remote wet mate couplers 144 , for hook up to the tree valves and to the downhole service lines 28 via the horizontal penetrators 126 . Installation and recovery of the coiled tubing string may be carried out from a lightweight intervention vessel, without the use of a BOP. The lower riser package includes upper and lower valves 138 , 140 (for example large bore gate valves) at least one of which may, if required in an emergency, be used to shear the coiled tubing string. FIG. 13 shows the tree in production mode with the EDP/LRP and riser removed and the swab valves 122 , 124 closed above the coiled tubing hanger 12 .
Finally, FIG. 14 corresponds to FIG. 13 but shows a modification in which the production conduit 34 intersects with the tree through bore above the coiled tubing hanger 12 , rather than below it.
Table 1 sets out barrier matrices for the completions described above, for various procedures and conditions.
Abbreviations
BOP
Blowout preventer
CSV
Circulation/service valve
CT
Coiled tubing
CTH
Coiled tubing hanger
CXT
Conventional tree
HXT
Horizontal tree
ITC
Internal tree cap
ITT
Installation test tool
LRP
Lower riser package
LSV
Lower swab valve
LTIV
Liner top isolation valve
PBV
Production bypass valve
PMV
Production master valve
PWV
Production wing valve
SSTT
Subsea test tree
TH
Tubing hanger
USV
Upper swab valve
ITC
Internal tree cap
WOV
Workover valve
TABLE 1
(follows)
COMPLETION TYPE
FIGS. 1 and 2
FIGS. 6 and 7
FIGS. 8 and 9
FIGS. 10 and 11
PROCEDURE
1 st Barrier
2 nd Barrier
1 st Barrier
2 nd Barrier
1 st Barrier
2 nd Barrier
1 st Barrier
2 nd Barrier
Foundation
Drill 36″ hole
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Run and cement 30″ conductor
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
and LP housing
Drill 12-1/4″ hole
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Drilling
N/A
N/A
Run and cement 6″ casing and
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
wellhead housing
Run BOP stack and marine riser
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Drill 8″ hole
Fluid
BOP
Fluid
BOP
Fluid
BOP
Fluid
BOP
Run 6″ liner
Fluid
BOP
Fluid
BOP
Fluid
BOP
Fluid
BOP
Drill 8″ hole
Fluid
BOP
Fluid
BOP
Fluid
BOP
Fluid
BOP
Run 6″ liner
Fluid
BOP
Fluid
BOP
Fluid
BOP
Fluid
BOP
Drill 8″ hole
Fluid
BOP
Fluid
BOP
Fluid
BOP
Fluid
BOP
Run 6″ liner
Fluid
BOP
Fluid
BOP
Fluid
BOP
Fluid
BOP
Drill 8″ hole
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Run 6″ liner and lower
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
completion with LTIV
Run 5″ upper completion and
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
expand onto the 6″ liner
Set casing plugs
Caing plug
Fluid
Casing plug
Fluid
Casing plug
Fluid
Casing plug
Fluid
Tree Installation
Retrieve BOP
Caing plug
Fluid
Casing plug
Fluid
Casing plug
Fluid
Casing plug
Fluid
Run HXT
Caing plug
Fluid
Casing plug
Fluid
Casing plug
Fluid
Casing plug
Fluid
Run BOP/LRP
Caing plug
Fluid
Casing plug
Fluid
Casing plug
Fluid
Casing plug
Fluid
Completion
Drill out/remove casing plugs
N/A
N/A
N/A
N/A
N/A
N/A
N/A
N/A
Drill 8″ hole
Fluid
BOP
Fluid
BOP
Fluid
BOP
Fluid
BOP
Run 6″ liner and lower
Fluid
BOP
Fluid
BOP
Fluid
BOP
Fluid
BOP
completion with LTIV
Pull HXT bore protector
LTIV
Fluid/BOP
LTIV
Fluid/BOP
LTIV
Fluid/BOP
LTIV
Fluid/BOP
Run 5″ upper completion
LTIV
Fluid/BOP
LTIV
Fluid/BOP
LTIV
Fluid/BOP
LTIV
Fluid/BOP
(outer tubing) and expand
onto the 6″ liner
Run CTH, lock and test
LTIV
Fluid/BOP/
LTIV
Fluid/BOP/
LTIV
Fluid/BOP/
LTIV
Fluid/BOP
CTH
CTH
CTH
CTH
Flow Test
Circulate to lighter fluid
LTIV
CSV
LTIV
CSV
LTIV
CSV
LTIV
CSV
Overpressure the LTIV and
PWV
Pressure Cap
PWV
Pressure cap
PWV
Pressure Cap
PMV
PWV
flow test the well
CSV
WOV
CSV
WOV
CSV
WOV
CSV
WOV
ITT
BOP
ITT
BOP
ITT
BOP
ITT
BOP
Isolate well at HXT
PMV
PWV
PMV
PBV
PMV
PBV
USV
LSV
Run ITC
CTH
ITC and
CTH
ITC and
N/A
N/A
N/A
N/A
BOP
BOP
Run CTH 2ary lockdown
N/A
N/A
N/A
N/A
CTH
BOP
N/A
N/A
Pull BOP/LRP
CTH
ITC
CTH
ITC
CTH upper
CTH lower
USV
LSV
seal
seal
Install controls cap by ROV
CTH
ITC
CTH
ITC
CTH upper
CTH lower
N/A
N/A
seal
seal
Produce to flow lines
CTH
ITC
CTH
ITC
CTH upper
CTH lower
USV
LSV
seal
seal
Tubing access workover with BOP
Pull controls cap
CSV
ITC
CTH
ITC
CTH upper
CTH lower
N/A
N/A
seal
seal
Pull ITC
CSV
BOP
CTH
BOP
CTH
BOP
N/A
N/A
Run LRP/
N/A
N/A
N/A
N/A
N/A
N/A
USV
LSV
BOP + marine riser
Run ITT
CSV
BOP
CTH
BOP
CTH
BOP
USV
LSV
Circulate the well to kill weight
Fluid
CSV + BOP
Fluid
CTH + BOP
Fluid
CTH + BOP
Fluid
BOP
Pull CTH
Fluid
BOP
Fluid
BOP
Fluid
BOP
Fluid
BOP
Replace CTH
Fluid
BOP
Fluid
BOP
Fluid
BOP
Fluid
BOP
Circulate the well to light weight
CSV
CSV + BOP
CTH
CSV + BOP
CTH
BOP
USV
LSV
Pull ITT
CSV
CSV + BOP
CTH
CSV + BOP
CTH
BOP
USV
LSV
Run ITC
CSV
ITC
CTH
ITC
CTH
BOP
N/A
N/A
Pull BOP stack +
CSV
ITC
CTH
ITC
CTH upper
CTH lower
USV
LSV
marine riser/LRP
seal
seal
Install controls cap
CSV
ITC
CTH
ITC
CTH upper
CTH lower
N/A
N/A
seal
seal
Tubing access workover with LWI
Vessel
Similar to above
Outer tubing retrieval workover
with BOP
Assumed to be impossible due to
tubing being expanded onto previous
casing
COMPLETION TYPE
FIGS. 12, 13 and 14
PROCEDURE
1 st Barrier
2 nd Barrier
COMMENTS
Foundation
Drill 36″ hole
N/A
N/A
Run and cement 30″ conductor
N/A
N/A
Assuming that well
and LP housing
foundation is needed as per
FIG. 15
Drill 12-1/4″ hole
N/A
N/A
Drilling
Run and cement 6″ casing and
N/A
N/A
HP housing has 6–8½″ nom.
wellhead housing
bore and no casing hanger
landing shoulder.H-4 profile
per 18¾″ system to allow
wide range of BOP stacks.
Run BOP stack and marine riser
N/A
N/A
18¾″ system or smaller 6″
minimum ID
Drill 8″ hole
Fluid
BOP
Run 6″ liner
Fluid
BOP
Drill 8″ hole
Fluid
BOP
Run 6″ liner
Fluid
BOP
Drill 8″ hole
Fluid
BOP
Run 6″ liner
Fluid
BOP
Drill 8″ hole
Fluid
BOP
Run 6″ liner and lower
Fluid
BOP
completion with LTIV
Run 5″ upper completion and
LTIV
Fluid/BOP
expand onto the 6″ liner
Set casing plugs
Casing plug
Fluid
Tree Installation
Alternatively, install the tree at the
same time as the WH housing and
drill thru tree.
Retrieve BOP
Casing plug
Fluid
Run HXT
Casing plug
Fluid
Run BOP/LRP
Casing plug
Fluid
LRP used in FIGS. 12–14
Completion
Drill out/remove casing plugs
Fluid
LRP
Drill 8″ hole
N/A
N/A
Drill into formation
Run 6″ liner and lower
N/A
N/A
Assumes LTIV That can be
completion with LTIV
opened by overpressure or
cyclic pressure
Pull HXT bore protector
N/A
N/A
Run 5″ upper completion
N/A
N/A
Assumes that no packer is
(outer tubing) and expand
used
onto the 6″ liner
Run CTH, lock and test
LTIV
Fluid/LRP/
Assumes no SSTT needed.
CTH
CTH run on CT installation
string, FIGS. 1, 6, 8
Flow Test
Circulate to lighter fluid
LTIV
CSV
Open CSV. Close when
complete
Overpressure the LTIV and
PMV
PWV
Flow test via PBV and ITT,
flow test the well
CSV
WOV
FIGS. 1–11. Disconnect/drive
USV
LSV
off by closing HXT values =>
no SSTT needed
Isolate well at HXT
USV
LSV
Close PMV and PBV
Run ITC
N/A
N/A
Run CTH 2ary lockdown
N/A
N/A
Maybe unnecessary
Pull BOP/LRP
USV
LSV
Assumed acceptable as seals
independently testable and on
different seal bores. LRP
use for FIGS. 12–14
Install controls cap by ROV
N/A
N/A
Produce to flow lines
USV
LSV
Open PMV and PWV
Tubing access workover with BOP
Pull controls cap
N/A
N/A
Pull ITC
N/A
N/A
Run LRP/
USV
LSV
BOP FIGS. 10, 11 18¾″ or
BOP + marine riser
smaller. 9″ min. ID.
LRP FIGS. 12–14
Run ITT
N/A
N/A
Circulate the well to kill weight
Fluid
LRP
Open CSV. Close BOP rams
on the ITT and circulate via
choke/kill, FIGS. 1–11
Pull CTH
Fluid
LRP
Open USV, LSV, FIGS. 10–14
Replace CTH
Fluid
LRP
Circulate the well to light weight
USV
LSV
Pull ITT
N/A
N/A
Run ITC
N/A
N/A
Pull BOP slack +
USV
LSV
marine riser/LRP
Install controls cap
N/A
N/A
Tubing access workover with LWI
Vessel
Similar to above
Outer tubing retrieval workover
with BOP
Assumed to be impossible due to
tubing being expanded onto previous
casing
FIGS. 15–18 are highly schematic half-sectional representations of a casing program that may be used with the wellhead housing 11 of the previous figures. FIGS. 15 and 16 are prior to tree installation; and FIG. 18 shows the tree 10 installed. Initially, a foundation is established using conductor casing 146 , for example a 13⅜″ conductor or larger. The size of the LP housing and foundation is substantially independent of the size of the rest of the system.
A hole section is then drilled, a first casing section 100 is run and cemented and the wellhead housing 11 established. This may be of small diameter (21.6 mm, 8½″ drift). A further hole section is then drilled and an expandable casing section 148 run, cemented and expanded to the bore diameter of the first casing section 100 . Expansion seals the casing section to the previously installed casing without the use of packers or the like. Methods for installing expandable tubulars are known in the art and will not be further elaborated here. The expansion pig may be run either from the top down or from the bottom up. However, the bottom up method is preferred, as then no hangers are needed.
Drilling continues and as many further casing sections 150 , 152 as may be needed to reach the reservoir 154 are installed successively. All casing sections are expanded to the bore diameter of the initial section 100 (e.g. 6″), to produce a parallel sided well. When needed, the BOP 68 is installed on the wellhead housing 11 . All casing sections are capable of withstanding the reservoir pressure.
Drilling is continued into the reservoir 154 as shown in FIG. 16 and a liner section 156 is installed and expanded to the casing diameter. The outer tubing string 98 is then run and expanded (preferably using the bottom up method) into sealing contact with the liner 156 , casing and wellhead 11 . Therefore no tubing hanger or packers are needed to support the tubing 98 and seal it in the wellhead housing 11 : see FIG. 17 . Also, the final top location of the tubing is not accurately predictable due to axial shrinkage during radial expansion. The liner 156 is perforated and a liner top isolation valve 160 or similar isolation device installed. Also shown in FIG. 17 is a tree stab 158 for sealing the tree 10 to a corresponding pocket in the wellhead housing 11 .
FIG. 18 shows the tree 10 attached to the wellhead housing 11 in place of the BOP and the BOP reinstalled on the tree. The coiled tubing string 14 and coiled tubing hanger 12 is then run on the installation string 32 and landed in the tree 10 . The coiled tubing string 14 may be used to carry downhole instrumentation, chemical injection and gas lift mandrels 162 , 164 , ESP's, separation equipment and the like, as discussed above, as well as any required service lines. These may be secured to the coiled tubing exterior as shown in FIGS. 3 and 4 . Preferably however they are enclosed within the coiled tubing bore as indicated in FIGS. 1 , 2 and 5 – 14 . FIG. 19 is a diagrammatic cross-section through the coiled tubing, showing two fluid containing service lines 166 , 168 and an electrical or optical service line 170 .
FIGS. 20–22 show an alternative casing program. Again no casing hangers are required at the wellhead housing 11 and each casing section is capable of withstanding the reservoir pressure. The casing sections are each expanded into seating contact with the previously installed section, but are of successively smaller diameters. For example a 30″ conductor casing 146 may be used, with the other casing diameters (when expanded) as follows:
100: 9⅝″; 148: 8⅝″; 150: 7⅝″; 152: 6⅝″
Referring to FIG. 21 , the final well section is drilled into the reservoir 154 and a (for example) 5⅝″ liner 156 and liner top isolation valve are 160 installed. The liner is expanded into sealing contact with the lowermost casing section 152 .
As shown in FIG. 21 , the outer tubing string 98 is run on a completion riser 174 and expanded at its lower end onto the production liner 156 . The tubing string 98 is suspended from an outer tubing hanger 172 landed, sealed and locked down in the wellhead housing 11 . No production packer is needed.
There are several possible methods of setting the outer tubing hanger 172 and facilitating the expansion of the outer tubing 98 onto the liner 156 . The preferred methods are based on the “top down” expansion principle. This is better for this particular well construction due to the tapering casing strings. The outer tubing 98 only eliminates the tubing/production casing annulus at the lower section. A “bottom up” approach is only readily usable if a correspondingly tapered outer tubing 98 is used. This is inconvenient due the number of trips required to set the different sizes of pig and the increased tubing costs at the top sections.
FIG. 22 shows a first setting method. The outer tubing hanger 172 is run on a tool 174 and drill pipe 176 . The expansion pig 178 is attached to coiled tubing 180 . The pig 178 is pumped down by pressurised fluid supplied through the drill pipe/coiled tubing annulus. The coiled tubing 180 provides a return path up the tool string. However there may be difficulties in running coiled tubing at the same time as drill pipe.
A preferred alternative is as shown in FIG. 23 . The bores of the THRT 174 and of the running string 176 are made large enough to drift the pig 178 . The pig is easier to install as the coiled tubing 180 can be run after the tubing hanger 172 has landed. The coiled tubing annulus again provides the pressurised fluid flow path for expansion of the outer tubing 98 , and the coiled tubing bore the return path.
There are various options for the seal interface between the wellhead housing 11 and the tree 10 . One consideration is the need to isolate the VX gasket from the produced fluids. FIG. 24 shows a wellhead/tree seal arrangement for a completion including an outer tubing hanger 172 . A seal pocket is provided at the upper internal diameter of the wellhead housing to interface a seal stab 158 on the tree. This corresponds somewhat to the FIG. 17 arrangement. The tree seal stab 158 has a drift diameter that allows passage of the tubing hanger to the bore of the well. This arguably is a single barrier to the environment if the VX gasket is discounted.
Alternatively, a seal pocket may be provided at the upper inside diameter of the outer tubing hanger 172 to interface a seal stab 158 on the tree, as shown in FIG. 25 . With this option, the outer tubing 98 must be installed prior to tree installation. However the arrangement is arguably closer to that found in a conventional christmas tree and may therefore more readily gain industry acceptance and/or regulatory approval.
The arrangement shown in FIG. 26 is similar to that shown in FIG. 24 , but includes a further seal pocket at the wellhead housing 11 inside diameter, to interface a further seal stab 182 from the coiled tubing hanger 12 or another component to be located in the bore 15 of the tree 10 . The arrangement shown in FIG. 17 may be modified likewise, so that the wellhead housing 11 accommodates a further seal stab e.g. from the coiled tubing hanger 12 . FIG. 27 is similar to FIG. 26 , except that the pocket for the further seal stab 182 is at the outer tubing hanger 172 upper inside diameter.
FIGS. 28–30 are diagrams of a third drilling program. Casing hangers are used in the wellhead housing 11 to suspend concentric casing strings 149 , 151 , 153 and production casing 157 . Each string is successively landed and expanded into sealing contact with the next outer string, preferably using a top down method such as shown in FIGS. 22 or 23 . Prior to expansion, a temporary annulus exists between a given casing string and the next outer casing string. This can be used for circulation/cementing. Packoffs are not needed due to the seal effected between the concentric strings. The expanded casing sizes may be as follows:
100: 9⅝″; 149: 7½″; 151: 7″; 153: 6½″; 157: 6″
As shown in FIG. 29 , outer tubing 98 is suspended in the wellhead 11 from tubing hanger 172 . The tubing 98 is then expanded onto the production liner 157 . Again the production liner has an isolation device such as a liner top isolation valve. No packer is needed and the tubing hanger 172 need not itself be sealed and locked to the wellhead housing 11 . (The expanded outer tubing 98 is sealed to the production casing 157 ).
FIG. 30 is a diagram showing the outer string hanger 172 and casing hangers 186 , 188 , 190 , 192 for the successive casing strings 149 , 151 , 153 , 157 , landed in the (consequently elongated) wellhead housing 11 . An interface with the tree seal stab 158 is also shown. Modification is of course possible in accordance with any of FIGS. 25–27 .
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A completion system comprises a christmas tree ( 10 ) mounted on a wellhead housing ( 11 ), a tubing hanger ( 12 ) landed in the tree or wellhead housing, the wellhead housing ( 11 ) being mounted on a casing string ( 100 ) and a tubing string ( 14 ) being suspended from the tubing hanger within the casing string; wherein, in use, the annulus defined between the tubing ( 14 ) and the casing ( 100 ) serves as a production bore. A second tubing string ( 98 ) is expanded into sealing engagement with the casing string ( 100 ) over at least a portion of their lengths. The annulus normally used to provide well service functions is thus eliminated. Well servicing is instead provided via the tubing string ( 14 ), which may be coiled tubing.
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TECHNICAL FIELD
This invention relates to the field of sensing of borehole parameters, particularly parameters of interest in the drilling of oilwell boreholes.
BACKGROUND OF THE INVENTION
In the directional drilling of oil well boreholes, it is not uncommon for the drillstring to become mechanically stuck within the borehole. The recovery and replacement cost associated with a stuck drillstring are very high. Accordingly, there is an interest in the art in developing methods for minimizing such recovery and replacement costs. Determining the free point of a stuck drillstring allows removal of the maximum possible quantity of drillstring from the wellbore on the first pass and thus reduction in the number of passes necessary for the attempted removal of the remaining drillstring.
There are two conventional methods for determining the Point in the drillstring below which the string is stuck and above which the string is free.
The Brouse method involves applying excess tension to the drillstring, i.e. overpull, and measuring the resultant stretch of the drillpipe. Using the measurements of applied force and stretch in view of a simple mechanical relationship determines the length of pipe above the free point. The method assumes that there exists a length of drillpipe of uniform physical dimensions and properties between the surface and the free point. Several problems are associated with the Brouse method. It is necessary to apply additional tensile loading to the drillstring to induce stretching of the pipe.
There exists a risk that depending upon the condition of the pipe, the drillstring could be torn apart by the application of the excess force. The problem becomes more serious in situations where various sizes of pipe, made from different materials, are used in a tapering configuration, e.g. as in horizontal drilling. The method is reasonably accurate when the drillstring between the stuck point and the surface consists of a number of sections of drillpipe each having similar physical properties and dimensions. The Brouse method becomes increasingly inaccurate with increasing drillstring complexity. Finally, the Brouse method is unable to estimate the free point if it occurs within the bottom hole assembly.
A wire line tool may also be used to determine the free Point. The wire line tool method requires that a tool be run inside the drillstring on an electric line. The tool is positioned near the estimated free point. The tool has means to fix its position relative to the drillstring. With the tool in place, tensile and rotational forces are applied to the drillstring. The relative movement of the tool ends is measured, and the location of the free point is determined from these measurements. Several problems are associated with the wire line tool method of free point determination. The drillstring is subjected to excess tensile and torsional forces which increase the risk of failure of the drillpipe as discussed above. The wireline tool method is very time consuming and expensive requiring the use of an electric wireline and qualified operators. The method is inherently unsafe due to the presence of the wireline in the drillpipe and requires elaborate precautions against a well blow out. The method is generally accurate in most situations.
What is needed in the art, is a method for determining the free point of a stuck drillstring which overcomes the above deficiencies.
SUMMARY OF THE INVENTION
A method for determining the free point of a drillstring that has become stuck in a borehole is disclosed. The borehole extends substantially downwardly through a formation from a to end to a bottom end. The drillstring includes a plurality of elements extending along the borehole from the top end of the borehole through the free point to the bottom end of the borehole. The elements below the free point are stuck and the elements above the free point are free to move. The method includes slacking off on the drillstring and determining an observed hookload for the drillstring during slackoff. The position of the free point is estimated. A calculated hookload is then calculated, assuming a truncated drillstring, wherein the truncated drillstring comprises the drillstring elements between the top end of the borehole and the estimated free point position. The calculated and observed hookloads are compared. The free point estimation, hookload calculation and comparison steps are repeated until the calculated hookload agrees with the measured hookload within a predetermined tolerance. The free point is found to correspond to a particular estimated free point if a calculated hookload based on a truncated drillstring extending between the top end of the borehole and the particular estimated free point agrees with the observed hookload within the predetermined tolerance.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 shows a force balance on a drillstring element.
FIGS. 2A, 2B, 2C and 2C and 2D show shows a flow chart outlining the method of the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENTS
A drillstring is used to drill an oil well borehole through a geological formation. The drillstring extends from a drilling platform on the surface of the formation to a bit at the bottom of the borehole and comprises a plurality of elements including drillpipe elements and a bottom hole assembly (BHA). Drillpipe elements extend from the drilling platform to the top of the BHA. The BHA extends from the bottom drillpipe element to the bit. The BHA includes the bit, reamers and stabilizers of the drillstring.
If it is believed that the drillstring has become stuck in the borehole, the drillstring is slowly slacked off and the hookload is observed during slackoff. The hookload stabilizes when the rock formation supports the weight of the drillstring below the free point. The stable hookload observed during slackoff is recorded and is defined as the observed slackoff hookload.
A value is calculated for the theoretical slackoff hookload for the drillstring from the bit to the top end of the drillstring by sequentially calculating the tensile forces on each element of the drillstring from the bit to the top end of the drillstring.
FIG. 1 shows a force balance on a bottom hole assembly element 2 illustrating the sources of normal force The forces on each element of the drillstring may be calculated using the equations for slacking off the drillstring:
Fn=((Ft.sub.b Δαsin θ).sup.2 +(Ft.sub.b Δθ+W sin θ.sup.2).sup.1/2 (1)
ΔFt=Wcosθ-μFn, (2)
Ft.sub.t =Ft.sub.b +ΔFt (3)
where:
Fn=normal force on element (lbf),
Ft b =tensile force on element bottom (lbf),
Ft t =tensile force on element top (lbf),
Δα=azimuth change over element (radians),
θ=mean inclination of element (radians),
Δθ=inclination change over element (radians),
W=air weight of element (lb),
ΔFt=incremental tension (lbf), and
μ=friction factor.
When proceeding sequentially upwardly from the bottom of the drillstring, the tensile force on the bottom of the element is equal to the tensile force on the top of the previous element in sequence, assuming that the geometry of the elements is the same.
The hydrostatic effect on the drillstring will change each time the geometry of the element cross-sectional area changes. The proper treatment of these changes requires that the true vertical depth at these changes is known. The hydrostatic pressure is calculated for that depth and the forces acting on the two cross sectional areas is calculated. To calculate the effective force Ft acting on the bottom of the upper element, the following manipulation is performed:
Ft.sub.bH =Ft.sub.t1 -Hπ/4(OD.sub.1.sup.2 -OD.sub.2.sup.2 -ID.sub.1.sup.2 +ID.sub.2.sup.2), (4)
where:
Ft bH =tensile force on bottom of element, corrected for hydrostatic forces,
Ft t1 =tensile force on top of previous element,
H=hydrostatic pressure acting on the element,
OD 1 =outer diameter of previous element,
OD 2 =outer diameter of element,
ID 1 =inner diameter of previous element, and
ID 2 =inner diameter of element.
Ft bH may then be substituted for Ft b in equation 3 above in order to calculate the forces on the element.
The observed slackoff hookload is compared to the calculated slackoff hookload. If the drillstring is stuck, the observed hookload value will be lower than the calculated hookload value.
If the drillstring is found to be stuck, a free point position is estimated. A calculated slackoff hookload is calculated for a truncated drillstring wherein the truncated drillstring comprises the drillstring elements between the platform and the estimated free point position. The calculated slackoff hookload for the truncated drillstring is compared to the observed slackoff hookload.
If the calculated slackoff hookload agrees with the observed slackoff hookload within a predetermined tolerance, e.g. within about 1%, the estimated free point is determined to correspond to the actual free point. If the calculated slackoff hookload does not agree with the observed slackoff hookload, the calculated slackoff hookload is recalculated based on a second truncated drillstring extending between the platform and the second estimated free point. The sequence is repeated until the calculated slackoff hookload agrees with the observed slackoff hookload within a predetermined tolerance.
FIGS. 2A, 2B, 2C and 2D are a flow chart outlining the process steps of the method of the present invention. Starting from the top of FIG. 2A, the observed slackoff hookload from file 2, drillstring data from file 8, historical survey data from file 12, casing data from file 16, and mud data from file 20 are input (functional blocks 4, 10, 14, 18, and 22) to initialize the system. Drillstring data includes the length, inner diameter, outer diameter and the specific weight of each drillstring element. Historical data includes previously measured values for depth, inclination and azimuth of the wellbore, as well as calculated values for the true vertical bit depth at each measurement depth.
Casing data includes measured depth at the bottom of each casing string and the inner diameter of the innermost string.
Mud data includes mud weight. The hydrostatic force acting on the bit is calculated (functional block 24).
The initial tension value is set equal to the upward pressure exerted by the hydrostatic column of fluid in the wellbore acting on the cross sectional area of the drillstring at the vertical depth of the bit increased by the weight on the bit.
Continuing from the top of FIG. 2B, the drillstring is divided into a plurality of computational elements (functional block 28). Data defining the elements is filed in the element file 26. The initial conditions and the data defining the elements are used to calculate the forces on the elements. The system flow passes from functional block 28 to the "change in geometry" test (functional block 32).
If the geometry of the element is different from the geometry of the previous element, the system flow passes to FIG. 2C.
Starting from the top of FIG. 2C, the hydrostatic pressure at the depth of the bottom of the element is calculated (functional block 42). The hydrostatic forces at the cross sections of the element and the previous element are calculated above (functional block 44) and the tensile force on the bottom of the element is recalculated (functional block 46) according to equation 2 given below. The system flow then returns to FIG. 2B at functional block 34.
If the element is the first element, if the geometry of the element is the same as the previous element, or if the tensile force on the bottom of the element has been recalculated according to the steps outlined in FIG. 2D, the system flow passes to the calculation of the normal force on the element and the change in tensile force over the element (functional block 34) and onto the calculation of the tensile force on the top of the element (functional block 36) according to equations 1, 2 and 3 above.
As the calculation of the forces on the element is completed, a "last element" test is conducted (functional block 38).
If the element is not the last element of the drillstring, the data defining the next element is retrieved (functional blocks 40) from file 26 and the loop is reentered at functional block 32 for calculation of the forces on the next element.
If the element is the last element of the drillstring, the system flow passes from the "last element" test of functional block 32 to FIG. 2D.
Starting from the top of FIG. 2D, the hook and block weight data from file 48 are entered and the slackoff hookload is calculated (functional block 50). The slackoff hookload is compared with the observed hookload (functional block 52). If the calculated hookload does not agree with the observed hookload within a predetermined tolerance, the lowest element of the drillstring is removed from the program and stored in the drillstring/survey element file 26. The hydrostatic pressure is calculated at the bottom of the new lowest element (functional block 60) and the system flow returns to FIG. 2B at functional block 34.
The normal force on the element and the change in tensile force over the element (functional block 36) and the tensile force on the bottom of the next element (functional block 38) are calculated for each element in the drillstring. When the last element is reached, the system flow passes to the FIG. 2D and the slackoff hookload for the shortened drillstring is calculated (functional block 50). The calculated slackoff hookload is again compared with the observed hookload (functional block 52). The above described steps are repeated until the calculated slackoff hookload agrees with the observed slackoff hookload within a predetermined tolerance.
When the calculated slackoff hookload agrees with the observed slackoff hookload within the predetermined tolerance, the test is satisfied and it is determined that the bottom depth of the lowest element of the drillstring corresponds to the depth of the free point.
The method of the present invention allows determination of the free point of a stuck drillstring. Unlike conventional methods for determining the free point, the method of the present invention does not involve the application of excess tensile or torsional forces to the drillstring, so that the method of the present invention does not increase the risk of drillstring failure. Unlike the conventional wireline method for determining the free point, the method of the present invention does not increase the risk of well blow out.
While preferred embodiments have been shown and described, various modifications and substitutions may be made thereto without departing from the spirit and scope of the invention. Accordingly, it is to be understood that the present invention has been described by way of illustrations and not limitation.
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A method for determining the free point of a stuck drillstring is disclosed. The method includes determining the hookload on the stuck drillstring, comparing the hookload on the stuck drillstring with the most recent hookload prior to drillstring sticking to determine the depth of the free point.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a mold for a sealing resin and used in the manufacture of a molded semiconductor package such as an IC package.
2. Prior Art
Semiconductor devices, such as an IC chip or LSI, are generally sealed in packages for protection, and mounted in equipment. Resin is used as a packaging material of this kind, and there are resin molded semiconductor packages.
With the general trend toward lighter, thinner, shorter and smaller equipment, progress has been made in reduction of the thickness of molded packages having a semiconductor device sealed in, that is, semiconductor packages.
For the resin materials for molded packages, thermosetting resins are used, and a semiconductor device is encapsulated with a resin material in a mold.
A mold comprises a top mold member and a bottom mold member which are combined with their parting faces in contact with each other. Both mold members cooperatively hold a lead frame member with the parting faces of the mold members so as to define the cavity around an IC chip held on the lead frame member. The top mold member includes a cull for heating a thermosetting resin material to plasticize it. On the other hand, the bottom mold member includes a pot for pre-heating a resin tablet to send the tablet to the cull so as to be further heated and plasticized, runners for transferring the plasticized resin from the cull, and gates for guiding the resin material from the runners to the cavities.
A semiconductor device to be encapsulated by resin molding using a mold has been bonded onto the island portion of the lead frame in the preceding step. The electrode terminals of the semiconductor device are connected through wires to the corresponding lead terminals of the lead frame.
The lead frame is set on the bottom mold member in such a way that the semiconductor device on the lead frame is located substantially in the center of the mold cavity. After the lead frame is set, the lead frame having the semiconductor device bonded thereto is held between parting faces of the top and the bottom mold members. Therefore, the lead frame is so arranged as to substantially divide the cavity into approximately equivalent halves. The plasticized resin passes through the runner and is injected into the cavity from the gate until it is filled. After the filling, the resin pressure in the cavity is maintained at a specified value, and when the resin is cured, the device encapsulation is finished.
Subsequently, a lead frame having the semiconductor device covered with the resin material is ejected from a mold, and the resin material cured in the runner and the cull are separated from a molding main body, and a resin-molded semiconductor package is formed as shown in FIG. 10(a). FIG. 10(a) is a plan view of a semiconductor package ejected from the mold, and FIG. 10(b) is a front view of the semiconductor package.
The semiconductor package 1 comprises a lead frame member 2 and an IC chip 3 fixed to the lead frame member 2 as clearly shown in FIG. 10(a). The lead frame member 2 has an island portion 2b supported through the intermediary of support portions 2a, and the IC chip is fixed to the island portion 2b. Respective electrode terminals of the IC chip 3 are connected through bonding wires, not shown, to corresponding lead terminals 2c of the lead frame member 2. A molding 4 of resin is formed so as to cover the IC chip 3 and the bonding wires.
In a conventional mold as described above, the gate provided in the bottom mold member is formed to have a groove with a U-shape cross section defined by a slanted bottom face inclined at an elevation angle as seen in the direction of the cavity from the cull and also by a pair of side faces. The resin material transferred into the cavity along the inclined bottom face of the gate is led smoothly into the cavity, so that the cavity is filled with the resin material without forming voids in the cavity.
However, the resin flow oriented by the inclined bottom face of the gate generally proceeds toward the upper half of the cavity defined by the top mold member. Therefore, out of the resin injected into the cavity from the gate, a larger proportion flows into the upper half of the cavity than into the lower half of the cavity below the level of the lead frame member. Moreover, there is the IC chip-mounted lead frame member intervening between the upper cavity portion and the lower cavity portion.
For this reason, the resin pressure in the upper cavity portion becomes higher than in the lower cavity portion. Accordingly, owing to the resin pressure from the upper cavity portion, the island portion supporting the IC chip is deformed to descend. On account of this, a resulting molded package is sometimes shaped such that the bottom face of the island portion is partially exposed at the reverse side of the molded package.
SUMMARY OF THE INVENTION
An object of the present invention is to provide a mold for molding a semiconductor package, which can distribute a resin material for sealing a semiconductor uniformly in a cavity and which prevents an island portion of the support member from being exposed from a molding main body.
According to the present invention, there is provided a mold for molding a semiconductor package comprising a pair of mold members for cooperatively holding therebetween a plate-form support member to retain a semiconductor device thereon and cooperatively defining a cavity surrounding the semiconductor device, the pair of mold members having parting faces in contact with each other, and a gate for guiding a resin molding material into the cavity, the gate being formed in the parting face of at least one of the pair of mold members, wherein the gate is defined by a groove including a slanted bottom face inclined at an elevation angle toward a half of cavity which is defined by the other mold member so as to orient the flow of the resin material toward the half of the cavity from the gate, and wherein in the slanted bottom face, an auxiliary groove is provided to cause the resin material, generally guided along the slanted bottom face, to be partially oriented toward a direction different from the general resin flow direction given by the slanted bottom face.
According to the mold in the present invention, the resin material supplied to the gate is oriented by the slanted bottom face of the gate, inclined at an elevation angle, toward that half of the cavity which is defined by the other mold member. However, since the slanted bottom face is provided with the auxiliary groove for orienting the resin material in a different direction from the direction of the resin flow by the slanted bottom face, part of the resin material supplied to the gate is thereby oriented to the other half of the cavity defined by the one mold member.
The resin flow oriented by the auxiliary groove enables the resin to flow equally into the two halves of the cavity divided by the support member. Consequently, the resin pressure in the other half cavity portion is raised to a level substantially equal to the one half cavity portion, thus compensating a difference in resin pressure between the two half cavity portions divided by the support member.
Therefore, according to the present invention, in the molding process for sealing a semiconductor device held on a plate-like support member, a resin material can be guided substantially equally into the two half cavity portions so that the whole cavity is filled substantially uniformly with the resin material. Hence, a good quality semiconductor package can be manufactured with high reliability without being subjected to a large degree of deformation such that the island portion of the support member holding a semiconductor device is exposed from the resin material.
The auxiliary groove is preferably provided near the apex of the slanted bottom face. At the apex of the slanted bottom face, there is the end portion of the gate open to the cavity, so that orienting the resin flow by the auxiliary groove can be done effectively.
The auxiliary groove may be a U-shape groove defined by the bottom face substantially parallel with the parting faces of the top and bottom mold members and also by a pair of tapered side faces divergently rising from the bottom face. The auxiliary groove in the form of this U-shape groove is advantageous in balancing the left and right portions of the resin flow along the auxiliary groove.
The auxiliary groove may be a V-shape groove defined by a pair of slanted side walls formed along the extending direction of the gate. The auxiliary groove in the form of this V-shape groove is particularly effective when the gate has a small width dimension.
The effect of the auxiliary groove can be further enhanced by giving a slope to the bottom of the auxiliary groove in the reverse direction to the sloping direction of the gate, in other words, by giving a depression angle to the bottom of the auxiliary groove toward the cavity. Because of this, the cavity can be filled more uniformly with the resin material. Since the edge formed by the slanting faces of the gate and the auxiliary groove forms the frail portion of the molded resin material, unnecessary portions of molding at the cull, the runner and the gate can be easily removed from the molded resin product without causing a breakaway to the corner portion of the molded product.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a partial perspective view, as seen from the runner, of the gate portion of a mold according to a first embodiment of the present invention;
FIG. 2 is a partial side view, as seen from the cavity side, of the gate portion of the mold according to the first embodiment;
FIG. 3(a) is a longitudinal sectional view showing a setting process for molding a semiconductor package with a mold according to the present invention;
FIG. 3(b) is a longitudinal sectional view showing a resin injecting process for molding a semiconductor package using the mold according to the present invention;
FIG. 3(c) is a longitudinal sectional view showing the completion of the resin injecting process for molding a semiconductor package with the mold according to the present invention;
FIG. 4 is a diagram similar to FIG. 1, which shows a second embodiment of the present invention;
FIG. 5 is a diagram similar to FIG. 2, which shows the second embodiment of the present invention;
FIG. 6 is a diagram similar to FIG. 1, which shows a third embodiment of the present invention;
FIG. 7 is a diagram similar to FIG. 2, which shows the third embodiment of the present invention;
FIG. 8 is a diagram similar to FIG. 1, which shows a fourth embodiment of the present invention;
FIG. 9 is a diagram similar to FIG. 2, which shows the fourth embodiment of the present invention;
FIG. 10(a) is a plan view of a semiconductor package according to the present invention in its manufacturing process; and
FIG. 10(b) is a front view of a semiconductor package according to the present invention in its manufacturing process.
DESCRIPTION OF PREFERRED EMBODIMENTS
The present invention will be described in detail with reference to the illustrated embodiments.
FIG. 1 is a partial perspective view of the gate portion of the mold according to a first embodiment of the present invention as seen from the runner. FIG. 2 is a partial side view as sheen from the cavity side. FIGS. 3(a), 3(b) and 3(c) are process step diagrams showing the molding process of a semiconductor package with a mold according to the present invention.
As shown in FIG. 3(a), a mold 10 according to the present invention includes a top mold member 11 and a bottom mold member 12. The two mold members 11 and 12 are combined with parting faces 11a and 12a in contact with each other. In the two parting faces 11a and 12a, upper and lower cavity portions 14 and 15 are formed which define a cavity 13 in cooperation with each other.
Additionally, in the illustrated example, in the parting face 11a of the top mold member 11, a cull 17 is formed which heats and plasticizes a thermosetting resin material 16 including silica and an epoxy resin binder, for example.
On the other hand, in the illustrated example, in the bottom mold member 12, a pot 18 is formed which preheats a tablet made of thermosetting resin material 16 to transfer the tablet to the cull 17. A plunger 19 for pushing the thermosetting resin material 16 into the cull 17 is incorporated in the pot 18, which is a cylinder for the plunger 19. In the parting face 12a of the bottom mold member 12, there are provided a runner 20 for conducting outward the plasticized resin material 16 from the cull 17 to a gate 21, and the gate 21 guides the resin material 16 from the runner 20 into the cavity 13.
Runners 20, gates 21 and cavities 13 are formed in pairs symmetrically with respect to the center axis of the pot 18 or the plunger 19.
As shown in FIG. 1, the gate 21 formed in the parting face 12a of the bottom mold member 12 is in the form of a U-shaped groove extending from the runner 20 toward the cavity 13. The U-shape groove 21 is defined by a slanted bottom face 21a inclined at an elevation angle toward the upper cavity portion 14 of the cavity 13, and also by a pair of slanted side faces 21b rising in the directions away from each other from the two sides of the slanted bottom face 21a. The slanted bottom face 21a orients the flow of the resin material 16 sent from the runner 20 to the gate 21 toward the upper cavity portion 14, that is, in the sloping direction of the slanted bottom face 21a. The two slanted side faces 21b serve to prevent the flow of the resin material 16 from leaning to left or right. The pair of the slanted side faces 21b extending much wider and upwardly facilitate releasing the cured resin material 16 from the gate 21.
An auxiliary groove 22 is formed at the apex of the slanted bottom face 21a, that is, at the end portion of the gate 21 open to the cavity 13.
As shown in FIGS. 1 and 2, the auxiliary groove 22 is a U-shape groove defined by a horizontal bottom face 22a parallel with the parting face 12a of the bottom mold member 12, and a pair of tapered side faces 22b divergency rising from both sides of the horizontal bottom face.
The horizontal bottom face 22a of the auxiliary groove 22 changes the direction of part of the resin material 16, which is flowing along the slanted bottom face 21a of the gate 21 toward the upper cavity portion 14 of the cavity 13, to a horizontal direction different from the sloping direction of the slanted bottom face 21a. The two tapered side faces 21 extending much wider and upwardly, as with the slanted side faces 21b, serve to prevent the flow of the resin material 16 from leaning to left or right, and facilitate releasing the cured resin material 16 from the gate 21.
Referring to FIGS. 3(a) to 3(b), description will be made of the molding process of the semiconductor package 1 by means of a mold 10 according to the present invention.
FIG. 3(a) shows a setting process. As shown in FIG. 10(a), in the setting process, while an IC chip 3 is fixed to the island portion 2b depressed below the level of the lead frame so as to be suitable for producing a thin molded package, the lead frame member 2 is held between the parting faces 11a and 12a of both top and bottom members 11 and 12 such that the lead frame member 2 divides the cavity into two approximately equivalent halves. Electrode terminals of the IC chip 3 are connected through corresponding bonding wires 5 to corresponding lead terminals 2c as shown in FIG. 10(a). In the setting process, a tablet 16 made of a resin material is charged into the pot 18, by which the tablet is pre-heated and softens.
FIG. 3(b) shows a process of filling a resin into the cavity 13. In the resin injecting process, the softened resin material 16 is extruded into the cull 17 by the plunger 19. The resin material 16 having an adequate viscosity as it was heated to an adequate temperature in the cull 17 is guided through the runner 20 and the gate 21 into the cavity 13 by the ensuing extrusion action of the plunger 19.
In this process, the slanted bottom face 21a of the gate 21 orients the resin material 16 flowing through the gate 21 toward the upper half 14 of the cavity as mentioned above. The horizontal bottom face 22a of the auxiliary groove 22 provided at the apex of the slanted bottom face 21a of the gate 21 orients part of the resin material 16 flowing along the slanted bottom face 21a of the gate 21 to a horizontal direction.
By the guiding action of the auxiliary groove 22, part of the resin material 16 is directed toward the lower half 15 of the cavity without all of the resin material 16 being directed toward the upper half 14 above the lead frame member 2. Therefore, as shown in FIG. 3(b), the resin material 16 is guided equally to the upper half 14 and the lower half 15 of the cavity. Consequently, the resin pressure in the upper half 14 of the cavity does not show a larger value than the lower half 15 of the cavity as is the case with the conventional mold. Therefore, the lead frame member 2 is not deformed or displaced in the cavity 13 by the large resin pressure difference as in the conventional mold.
Therefore, as shown in FIG. 3(c) illustrating the completion of the resin injecting process, the lead frame member 2 and the IC chip 3 fixedly mounted on it are not swerved upward or downward. While the predetermined pressure at which the resin material 16 is filled in the cavity 13 is maintained, the plasticized resin material 16 is cured. For this reason, the island portion 2b is not exposed from the molding 4 by the deformation of the lead frame member 2, so that an adequate semiconductor package 1 is manufactured in which the IC chip 3 fixed to the island portion 2b is sealed in an adequate position approximately in the center of the molding 4.
A second embodiment of the present invention will be described.
In FIGS. 4 and 5 are diagrams in the second embodiment, which correspond to FIGS. 1 and 2 in the first embodiment.
In the example shown in FIGS. 4 and 5, the auxiliary groove 22 is a V-shape groove defined by a pair tapered side faces 22b. The bottom portion 22c of the auxiliary groove 22, expressed by a line of intersection of the two slanted side faces 21b, is parallel with the parting line 12a.
Therefore, the auxiliary groove 22, which is a V-shape groove, serves to orient, to the lower half 15 of the cavity, part of the flow of the plasticized resin material 16 oriented to move toward the upper half 14 of the cavity along the slanted bottom face 21a of the gate 21 as with the auxiliary groove 22 shown in FIGS. 1 and 2. Consequently, the lead frame member 2 can be securely prevented from being deformed or displaced by the difference in resin pressure between the two halves of the cavity.
With the V-shape auxiliary groove 22, the horizontal bottom face 22a in the U-shape groove 22 shown in FIGS. 1 and 2 is not required. Therefore, the V-shape auxiliary groove 22 is suitable for use in combination with a gate 21 in the form of a narrow groove, which has the slanted bottom face 21a with a small width.
A third embodiment of the present invention will now be described.
FIGS. 6 and 7 are diagrams in the third embodiment, which correspond to FIGS. 1 and 2 in the first embodiment.
In the example shown in FIGS. 6 and 7, the auxiliary groove 22 is a U-shape groove defined by a bottom face 22a and a pair of tapered side faces 22b as in the example shown in FIGS. 1 and 2. In the third embodiment, however, the bottom face 22a is not parallel with the parting face 12a but inclined in the reverse direction to the direction of the slanted bottom face 21a, that is, inched at an elevation angle toward the lower half 15 of the cavity 13.
Therefore, the bottom face 22a is inched in the reverse direction to the direction of the slanted bottom face 21a to more positively form a strong flow of the resin material 16 toward the lower half 15 of the cavity, for which reason the resin material 16 can be injected evenly into the upper half 14 and the lower half 15 of the cavity in a more balanced manner. Accordingly, the deformation and the displacement of the lead frame member 2 due to the difference in resin pressure between the two halves of the cavity can be prevented more securely.
The edge 23 defined by a line of intersection of the bottom face 22a and the slanted bottom face 21a forms a frail portion of the cured resin material 16 at an external portion of the molding 4 outside the cavity 13 Therefore, when portions of molding at the cull, the runner and the gate are removed from the main body of the molded product 4, unnecessary portions of molding at the cull, the runner and the gate of the molding can be removed easily without causing a breakaway to the corner portion of the molding 4.
A fourth embodiment of the present invention will next be described.
FIGS. 8 and 9 diagrammatically correspond to FIGS. 1 and 2, and show a fourth embodiment in which the V-shape auxiliary groove 22 is inclined in the reverse direction to the direction of the slanted bottom face 21a.
In the embodiment shown in FIGS. 8 and 9, the bottom 22c, which is defined by the intersection of a pair of tapered side faces 22b which define the V-shape groove 22, is inclined at an elevation angle toward the lower half 15 of the cavity 13.
Therefore, according to the fourth embodiment, like in the third embodiment, it is possible to more positively form a strong flow of the resin material 16 to the lower half 15 of the cavity. Thus, the resin material 16 can be injected more evenly into the upper half 14 and the lower half 15 of the cavity in a more balanced manner. Consequently, it is possible to more securely prevent the deformation and the displacement of the lead frame member 2 due to the difference in resin pressure between the two halves of the cavity. Moreover, this embodiment is advantageous when it is applied to the gate 21 having a slanted bottom face 21a with a narrow width. Furthermore, as described in the third embodiment, unnecessary portions of molding at the cull, the runner and the gate can be removed easily without causing a breakaway to the corners of the molding 4.
In the above description, the auxiliary grooves for changing the direction of the flow of part of the resin material flowing through the gate 21 have been U-shape grooves defined by the bottom face 22a and a pair of the tapered side faces 22b or V-shape grooves defined by a pair of the tapered side faces 22b. Instead of those types of grooves, an auxiliary groove with any other type of cross section, a circular cross section, for example, may be provided near the apex of the slanted bottom face and along the slanted bottom face of the gate.
The examples in which a single auxiliary groove is formed at the apex of the slanted bottom face of the gate, but a plurality of auxiliary grooves may be formed in parallel with each other, if needed.
In addition, the present invention can be applied to molds wherein an auxiliary resin supply port to serve as an auxiliary means for the gate is formed in the mold member other than the mold member which has the gate formed therein.
It ought to be noted that the present invention is not limited to the embodiments described above, and various modifications and variations can be made in the present invention without departing from the spirit of the present invention and are not excluded from the scope of the present invention.
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A mold for molding a semiconductor package which is capable of guiding a resin material for encapsulating a semiconductor device uniformly into the cavity and prevents the island portion of the support member from being exposed from the molding main body, the mold comprising a pair of mold members for encapsulating a semiconductor device held on the support member, and a gate for guiding a molding resin material into the cavity, the gate being provided in the parting face of parting face of at least one of the mold members, wherein the gate is defined by a U-shape groove including the slanted bottom face inclined at an elevation angle toward the cavity to orient the flow of the resin material, supplied to the gate, toward the half of the cavity defined by the other mold member from the gate, and wherein in the slanted bottom face, there is provided an auxiliary groove for making the resin material, generally guided along the slanted bottom face, partially oriented to a direction different from the direction of the resin flow oriented by the slanted bottom face.
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This application is a division of U.S. patent application Ser. No. 08/536,071, filed Sep. 29, 1995, now U.S. Pat. No. 5,641,563, which is a continuation of U.S. patent application Ser. No. 08/070,270, filed Jun. 2, 1993, now abandoned.
BACKGROUND OF THE INVENTION
1. Brief Description of the Invention
The invention is drawn toward absorbent, durable nonwoven articles, such as wipes, and methods for their manufacture.
2. Related Art
Synthetic wiping articles comprised of a nonwoven web made from polyvinyl alcohol (PVA) fibers and subsequently coated with covalently crosslinked PVA binder resins are known and have been sold as commercial products for many years. Chemically crosslinked PVAs provide distinct advantages in their usage in synthetic wipes. They increase and improve the elements of a dry wipe, non-linting of the wipe surface, mechanical strength, hydrophilic properties, and may also be cured in the presence of pigments to generate a colored wiping product. While their use has enjoyed considerable success, the currently known PVA binders used in synthetic wipes are chemically crosslinked in immersion baths containing potentially toxic materials, such as formaldehyde, various dialdehydes, methylolamines, and diisocyanates.
Glass and other fibers are sometimes sized (i.e., coated) with PVA coatings insolubilized with polyacrylic acid, or crosslinked with metal complexes, such as aluminum, titanium, silicon, or zirconium chelates, and the like.
U.S. Pat. No. 3,253,715 describes boil proof nonwoven filter media comprising a nonwoven fiber substrate and a binder comprising polyvinyl alcohol and polyacrylic acid. Although cellulosic fibers suitable for filters are described, there is no mention of polyvinyl alcohol fibers having utility. The polyvinyl alcohol fibers used in the present invention are prone to severe shrinkage under the pH and/or temperature conditions described in the '715 patent. In addition, the inventors herein have found that ratios of polyacrylic acid to polyvinyl alcohol in binders described in the '715 patent result in strong, but extremely rubbery, absorbent articles with poor "hand" and dry-wipe properties.
Natural chamois is a highly absorbent article derived from a goat-like antelope, and is commonly used to dry automobiles after washing. The absorbent properties of natural chamois have been emulated in several "synthetic chamois." Synthetic chamois commercially available may be formed from PVA fibers and a PVA binder crosslinked by formaldehyde, which undesirable for ecological reasons. Other synthetic chamois are known to be made from nonwoven fibers and an originally hydrophobic acrylic latex binder which has functional groups to make the binder, and thus the article, hydrophilic. These latter are inexpensive, but have very high drag property.
It would be desirous to develop a nonwoven article suitable for use in absorbing hydrophilic materials employing hydrophilic binders and fibers, without the use of formaldehyde. Such an article would allow the articles to exhibit high durability, good hand properties, low drag, and good dry-wiping properties (picks up water with no streaking) while maintaining absorption and "wet out" properties comparable to known articles. Such articles could be produced using ingredients and methods which are not as harmful to manufacturing personnel, users or the environment as are currently used ingredients. Finally, it would be advantageous if such binders could be cured in the presence of pigments to generate colored wiping products.
SUMMARY OF THE INVENTION
In accordance with the present invention, absorbent nonwoven articles are presented which can be produced using binder crosslinking agents which are less troublesome to handle, and which afford the inventive articles with as good or better absorbency and physical properties than known articles. In addition, certain preferred embodiments of the inventive articles may be made without the use of any chemical crosslinkers.
As used herein the term "absorbent" means the articles of the invention are hydrophilic (and therefore absorbent of aqueous materials).
Thus, a first aspect of the invention is an absorbent nonwoven article comprising:
(a) a nonwoven web comprised of organic fibers, the organic fibers comprised of polymers having a plurality of pendant fiber hydroxyl groups; and
(b) a binder comprising an at least partially crosslinked and at least partially hydrolyzed polymeric resin having a plurality of pendant resin hydroxyl groups, the resin crosslinked by a crosslinking agent, the crosslinking agent selected from the group consisting of organic titanates and amorphous metal oxides, the polymeric resin derived from monomers selected from the group consisting of monomers within the general formula ##STR2## wherein: X is selected from the group consisting of Si(OR 4 OR 5 OR 6 ) and O(CO)R 7 ; and
R 1 -R 7 inclusive are independently selected from the group consisting of hydrogen and organic radicals having from 1 to about 10 carbon atoms, inclusive, and combinations thereof.
Preferably, the binder is bonded to at least a portion of the organic fibers through bonds between the pendant fiber hydroxyl groups, a bonding agent, and the pendant resin hydroxyl groups, wherein the crosslinking agent and bonding agent are independently selected from the group consisting of organic titanates and amorphous metal oxides. Also preferred articles in accordance with this aspect of the invention are those wherein the crosslinking agent and bonding agent are the same compounds, and wherein R 4 -R 7 inclusive are methyl (--CH 3 ).
Two particularly preferred articles within this aspect of the invention are those in which the organic titanate crosslinking and/or bonding agent is dihydroxybis(ammonium lactato)titanium or a titanium complex with an alpha-hydroxy acid (e.g., lactic acid) and an alditol (e.g., D-glucitol).
As used herein the terms "bond" and "bonding" are meant to include hydrogen bonds, hydrophobic interactions, hydrophilic interactions, ionic bonds, and/or covalent bonds. The term "crosslinking" means chemical (covalent or ionic) crosslinking.
Especially preferred binders useful in this and other aspects of the invention are aqueous compositions comprising copolymers of vinyl trialkoxysilane and vinyl monomers such as vinyl/acetate, at least partially hydrolyzed with alkali, and at least partially crosslinked with inorganic ions and chelating organic titanates. The inorganic ions (e.g., aluminum, zirconium) react or otherwise coordinate with silanol groups, while the titanates react with secondary hydroxyl groups on the resin. This unique dual curing approach, with possibly different crosslinking chain lengths, allows intermolecular bonding between the PVA polymers of the binder and, theoretically, between the fiber hydroxyl groups and PVA polymers of the binder.
A second aspect of the invention is drawn toward nonwoven absorbent articles similar to those of the first aspect of the invention, wherein the crosslinking agent is selected from the group consisting of dialdehydes, titanates, and amorphous metal oxides.
A third aspect of the invention is an absorbent nonwoven article comprising:
(a) a nonwoven web comprised of a plurality of organic fibers comprising polymers having a plurality of pendant hydroxyl groups; and
(b) a binder coating at least a portion of the fibers, the binder comprising polyvinyl alcohol insolubilized with an effective amount of a polymeric polycarboxylic acid (preferably polyacrylic acid).
Preferred within this aspect of the invention are those articles wherein all of the polymers making up the fibers are at least partially hydrolyzed polymerized monomers selected from the group consisting of monomers within the general formula ##STR3## with the provisos mentioned above. The nonwoven web may further include a minor portion of fibers selected from the group consisting of cotton, viscose rayon, cuprammonium rayon, polyesters, polyvinyl alcohol, and combinations thereof.
In contrast to the articles described in the above-mentioned U.S. Pat. No. 3,253,715; we have found that very low amounts of polymeric polycarboxylic acid (in the range of 1 to 5 wt. % as weight of total binder weight) afford the best wiping properties while effectively eliminating binder washout. Further, we have found that pH (negative logarithm of the hydrogen ion concentration in aqueous compositions) ranging from 3 to 3.3 specified by the above-mentioned '715 patent is suitable for the present invention, but pH values up to 4.6 may be utilized, which is much more useful for reducing web shrinkage. The articles of this aspect of the invention employ a polymeric polycarboxylic acid to insolubilize aqueous polyvinyl alcohol, thereby providing absorbent articles with superior water absorption, dry-wipe, and improved strength compared to known articles.
A fourth aspect of the invention is an absorbent nonwoven article comprising:
(a) a nonwoven web comprised of organic fibers, the organic fibers comprised of polymers having a plurality of pendant hydroxyl groups; and
(b) a binder coated onto at least a portion of the fibers comprising syndiotactic polyvinyl alcohol, the syndiotactic polyvinyl alcohol having a syndiotacticity of at least 30%.
Articles employing the binder system mentioned in part (b) of this aspect of the invention employ syndiotactic polyvinyl alcohol (s-PVA) as a major (or only) component in the binder. The advantage of this binder is that s-PVA may be employed without a chemical crosslinking agent. This is because s-PVA tends to form microcrystalline regions. Chemical crosslinking through the use of titanates, inorganic ions, and dialdehydes may be employed, but they are rendered optional.
A fifth aspect of the invention is a method of making an absorbent nonwoven article, the method comprising:
(a) forming an open, lofty, three-dimensional nonwoven web comprised of organic fibers, the organic fibers comprised of polymers having a plurality of pendant hydroxyl groups;
(b) entangling the fibers of the web using means for entanglement to form an entangled fiber web;
(c) coating a major portion of the fibers of the entangled fiber web with a binder precursor composition to form a first coated web having first and second major surfaces, the binder precursor composition adapted to form the binder of the second aspect of the invention; and
(d) exposing the first coated web to energy sufficient to at least partially cure the binder precursor composition to form a nonwoven bonded web of fibers.
Preferred are those methods wherein the before step (c) the entangled fiber web is calendered, and those methods wherein after step (c) the first coated web is coated on at least one of its first and second major surfaces with a second binder precursor composition. Also preferred are those methods wherein the exposing step includes drying the second binder precursor composition uniformly to form a dried and cured nonwoven web having a surface coating, and those methods wherein the dried and cured nonwoven web is calendered, thereby smoothing and fusing the surface coating.
A sixth aspect of the invention is another method of making an absorbent nonwoven article comprised of a nonwoven web of fibers, at least a portion of the fibers having a binder coated thereon, the method comprising:
(a) forming a nonwoven web comprised of a plurality of organic fibers comprising polymers having a plurality of pendant fiber hydroxyl groups, a major portion of the polymers comprising polyvinyl alcohol;
(b) entangling the fibers of the web using means for entanglement to form an entangled fiber web;
(c) coating a major portion of the fibers of the entangled fiber web with a binder precursor composition to form a first coated web having first and second major surfaces, the binder precursor composition consisting essentially of polyvinyl alcohol and an effective amount of a polymeric polycarboxylic acid; and
(d) exposing the first coated web to energy sufficient to insolubilize the polyvinyl alcohol resin to form a nonwoven bonded web of fibers.
Optionally, bonding and crosslinking agents, as discussed herein, may be added to the binder precursor composition.
Finally, a seventh aspect of the invention is another method of making an absorbent nonwoven article comprised of a nonwoven web of fibers, at least a portion of the fibers having a binder coated thereon, the method comprising:
(a) forming a nonwoven web comprised of organic fibers, the organic fibers comprised of polymers having a plurality of pendant hydroxyl groups;
(b) entangling the fibers of the web using means for entanglement to form an entangled fiber web;
(c) coating a major portion of the fibers of the entangled fiber web with a binder precursor composition to form a first coated web having first and second major surfaces, the binder precursor composition consisting essentially of syndiotactic polyvinyl alcohol having a syndiotacticity of at least 30%; and
(d) exposing the first coated web to energy sufficient to at least partially cure the binder precursor composition to form a nonwoven bonded web of fibers.
An important aspect of the invention is that articles of the invention may employ inventive binders which allow the articles to exhibit high durability, good feel, reduced drag, and good dry wiping properties while maintaining comparable water absorption and "wet out" properties to existing wipes. In addition, wiping articles of the present invention may also be cured in the presence of pigments to generate colored wiping products.
Preferred articles within the invention may also include in the binder efficacious amounts of functional additives such as, for example, fillers, reinforcements, plasticizers, grinding aids, and/or conventional lubricants (of the type typically used in wiping articles) to further adjust the absorbance, durability, and/or hand properties.
The binders useful in the articles of the invention improve on conventional formaldehyde cross-linking agents which tend to embrittle the web fibers, reducing web strength, softness, and absorption, and which present chemical hazards.
Regarding the methods of the invention, in preferred methods the "exposing" step is preferably carried out in a fashion to afford uniform drying throughout the thickness of the web. Typically and preferably the exposing step is a two stage process wherein the coated web is first dried at a low temperature and subsequently exposed to a higher temperature to cure the binder precursor. In some embodiments, a third, higher temperature curing step is employed. As discussed herein below, to achieve uniformly dried and cured articles, both major surfaces of the uncured web are preferably exposed to a heat source simultaneously, or both major surfaces are sequentially exposed to the heat source. The methods of the invention may also encompass perforating and slitting the dried and cured bonded nonwoven into various finished products.
Further aspects and advantages of the invention will become apparent from the drawing figures and description of preferred embodiments which follows.
BRIEF DESCRIPTION OF THE DRAWING
FIG. 1 is a perspective view of a wipe made in accordance with the invention;
FIG. 2 is a cross-section along the lines 2--2 of the article of FIG. 1; and
FIG. 3 is a schematic diagram of a preferred method of making articles of the invention.
DESCRIPTION OF PREFERRED EMBODIMENTS
1. Articles Employing Chemically Crosslinked PVA Binders
Embodiments within this aspect of the invention include articles comprising a nonwoven web of fibers having coated thereon a binder comprising polyvinyl alcohol (preferably silanol modified) crosslinked with inorganic ions, chelating organic titanates, or combinations thereof.
The nonwoven web of fibers may be made from many types of hydrophilic fibers, and may include a minor portion of hydrophobic fibers, selected from the following fiber types: cellulosic-type fibers, such as PVA (including hydrolyzed copolymers of vinyl esters, particularly hydrolyzed copolymers of vinyl acetate), cotton, viscose rayon, cuprammonium rayon and the like, and thermoplastics such as polyesters, polypropylene, polyethylene and the like. The preferred cellulosic-type fibers are rayon and polyvinyl alcohol. Webs containing 100% PVA fibers, 100% rayon fibers, and blends of PVA fibers and rayon fibers in the wt. % range of 1:100 to 100:1 are within the invention, and those webs having PVA:rayon within the weight range of 30:70 to about 70:30 are particularly preferred in this aspect of the invention, since the coated products exhibit good hydrophilicity, strength, and hand.
Some aspects of the nonwoven fiber web are common to all article embodiments of the invention. The fibers employed typically and preferably have denier ranging from about 0.5 to about 10 (about 0.06 to about 11 tex), although higher denier fibers may also be employed. Fibers having denier from about 0.5 to 3 (0.06 to about 3.33 tex) are particularly preferred. ("Denier" means weight in grams of 9000 meters of fiber, whereas "tex" means weight in grams per kilometer of fiber.) Fiber stock having a length ranging from about 0.5 to about 10 cm is preferably employed as a starting material, particularly fiber lengths ranging from about 3 to about 8 cm.
Nonwoven webs of fibers for use in the articles of the invention may be made using methods well documented in the nonwoven literature (see for example Turbak, A. "Nonwovens: An Advanced Tutorial", Tappi Press, Atlanta, Ga., (1989). The uncoated (i.e., before application of any binder) web should have a thickness in the range of about 10 to 100 mils (0.254 to 2.54 mm), preferably 30 to 70 mils (0.762 to 1.778 mm), more preferably 40 to 60 mils (1.02 to 1.524 mm). These preferred thicknesses may be achieved either by the carding/crosslapping operation or via fiber entanglement (e.g., hydroentanglement, needling, and the like). The basis weight of the uncoated web preferably ranges from about 50 g/m 2 up to about 250 g/m 2 .
Binders within this aspect of the invention preferably are crosslinked via secondary hydroxyl groups on the PVA backbone with chelating organic titanates, and optionally with dialdehydes such as glyoxal. The resultant binder system will theoretically further react with hydroxyl groups on the fibers when cured at elevated temperatures to produce coated webs with excellent wiping properties.
Particularly preferred are "dual" crosslinked binders, wherein an amorphous metal oxide coordinates with silanol groups on the PVA backbone and titanates and/or glyoxal coordinate with secondary hydroxyl groups on the PVA backbone.
Silanol modified PVA's used in the present invention may be made via the copolymerization of any one of a number of ethylenically unsaturated monomers having hydrolyzable groups with an alkoxysilane-substituted ethylenically unsaturated monomer. Examples of the former are vinyl acetate, acetoxyethyl acrylate, acetoxyethylmethacrylate, and various propyl acrylate and methacrylate esters. Examples of alkoxysilane-substituted ethylenically unsaturated monomers include vinyl trialkoxysilanes such as vinyl trimethoxysilane and the like.
One particularly preferred silanol-modified PVA may be produced from the copolymerization of vinyl acetate and vinyl trialkoxysilane, followed by the direct hydrolysis of the copolymer in alkaline solution (see below). One commercially available product is that known under the trade designation "R1130" (Kuraray Chemical KK, Japan). This preferred base copolymer contains from about 0.5 to about 1.0 molar % of the silyl groups as vinylsilane units, a degree of polymerization of about 1700, and degree of hydrolysis of the vinyl acetate units preferably of 99+%.
The theoretical crosslink density may range from 1 to about 40 mole % based on mole of ethyleneically unsaturated monomer. This may be achieved by addition of one or more aqueous titanates and, optionally, dialdehyde/NH 4 Cl solutions to a polyvinyl alcohol binder resin. Though dialdehydes such as glyoxal and several classes of titanium complexes have been shown to crosslink aqueous compositions of polyvinyl alcohol, we have found that chelating titanates such as dihydroxybis(ammonium lactato) titanium (available under the trade designation "Tyzor LA" from du Pont) and titanium orthoesters such as Tyzor 131 provide excellent crosslinking for wiping articles described in this invention. It is desired that crosslinking be avoided until curing conditions (i.e., high temperatures) are present. Thus, organic acids, such as citric acid, may help to stabilize titanates such as dihydroxybis(ammonium lactato) titanium in aqueous compositions until the binder precursors are exposed to crosslinking and curing conditions.
To improve the tensile and tear strength of the inventive articles, and to reduce lint on the surface of the articles, it may be desirable to entangle (such as by needletacking, hydroentanglement, and the like) the uncoated web, or calender the uncoated and/or coated and cured nonwoven articles of the invention. Hydroentanglement may be employed in cases where fibers are water insoluble. Calendering of the binder coated web at temperatures from about 5° to about 40° C. below the melting point of the fiber may reduce the likelihood of lint attaching to the surface of the inventive articles and provide a smooth surface. Embossing of a textured pattern onto the wipe may be performed simultaneously with calendering, or in a subsequent step.
In addition to the above-mentioned components of the articles of this invention, it may also be desirable to add colorants (especially pigments), softeners (such as ethers and alcohols), fragrances, fillers (such as for example silica, alumina, and titanium dioxide particles), and bactericidal agents (for example iodine, quaternary ammonium salts, and the like) to add values and functions to the wiping articles described herein.
Coating of the binder resin may be accomplished by methods known in the art, including roll coating, spray coating, immersion coating, gravure coating, or transfer coating. The binder weight as a percentage of the total wiping article may be from about 1% to about 95%, preferably from about 10% to about 60%, more preferably 20 to 40%.
2. Articles Employing PVA-PA Blends as Binders
The absorbent nonwoven articles in accordance with this aspect of the invention comprise a nonwoven web of a plurality of organic fibers comprising polymers having a plurality of pendant hydroxyl groups, a major portion of the polymers being at least partially hydrolyzed polymerized monomers selected from the group consisting of monomers within the general formula ##STR4## wherein X is O(CO)R 7 the provisos mentioned above. A binder coats at least a portion of the fibers, the binder consisting essentially of polyvinyl alcohol insolubilized with an effective amount of polyacrylic acid. Optionally, chemical crosslinking agents and/or bonding agents may also be employed.
The nonwoven web of fibers is substantially the same as that described in Section 1 above. Any fiber type, such as polyesters, polyolefins, cellulosics, acrylics, and the like, may be employed, alone or in combination. Preferably, the nonwoven web of fibers comprises one or more of the following fibers: cotton, viscose rayon, cuprammonium rayon, polyvinyl alcohols including hydrolyzed copolymers of vinyl esters, particularly hydrolyzed copolymers of vinyl acetate and the like. Preferred cellulosic-type fibers are rayon and polyvinyl alcohol. Blends of rayon and polyvinyl alcohol fibers in the weight ranges given above in Section 1 are preferred.
The fiber denier and length are also as previously described in Section 1 above, as well as the preferred ranges for uncoated web thickness and weight.
Coating of the binder resin may accomplished by the previously mentioned methods, including roll coating, spray coating, immersion coating, transfer coating, gravure coating, and the like. The binder weight as a percentage of the total nonwoven article weight for this aspect of the invention may range from about 5% to about 95%, preferably from about 10% to about 60%, more preferably 20 to 40%.
Polymeric polycarboxylic acids useful in the invention include polyacrylic acid, polymethacrylic acid, copolymers of acrylic acid, methacrylic acid or maleic acid containing more than 10% acidic monomer, provided that such copolymers or their salts are water soluble the specified pH levels; and vinyl methyl ether/maleic anhydride copolymer.
Polyacrylic acid, the most preferred polymeric polycarboxylic acid useful in the present invention preferably has a weight average molecular weight ranging from about 60,000 to about 3,000,000. More preferably, the weight average molecular weight of polyacrylic acid employed ranges from 300,000 to about 1,000,000.
Optionally, small amounts (i.e., less than about 5 wt. % of the total weight of binder) of additional monomers (such as, for example, functionalized acrylate monomers like hydroxyethylmethacrylate, vinyl azlactone monomers, and the like) may be incorporated in the PVA binder polymer to reduce binder washout during repeated use.
As with previously described embodiments, chemical crosslinkers may be used. Preferred crosslinkers are titanates, dialdehydes, borates, and the like.
The nonwoven articles of this aspect of the invention may be calendered as previously described in Section 1 to reduce lint on the surface of the article and provide a smooth surface for printing. Embossing of a textured pattern onto the wipe may be performed simultaneously with calendering, or in a subsequent step.
The above-mentioned optional components (colorants, softeners, fragrances, fillers) may also be employed in the nonwoven articles of this aspect of the invention.
3. Articles Employing Binders Comprising Syndiotactic PVA
Triad syndiotacticity, as used herein, means that of a triad of three pendant hydroxyl groups, the hydroxyl groups are positioned in an alternating pattern from side to side along the polymer chain. This is opposed to atactic, which means that the hydroxyl groups are randomly arranged, and isotactic, meaning the hydroxyl groups are positioned on the same side of the polymer chain.
Nonwoven absorbent articles within this aspect of the invention comprise a nonwoven web of fibers comprised of polymers having a plurality of pendant hydroxyl groups. The binder for articles within this aspect of the invention comprises polyvinyl alcohol having a syndiotacticity of at least 30%. Optionally, a chemical crosslinking agent may also be present.
The nonwoven web of fibers comprises fibers substantially the same as those described above as useful for the other articles of the invention. The fiber length and denier, and uncoated web thickness and weight are also as above-described in Section 1. Coating of the binder resin may be accomplished by the above-mentioned methods known in the art including roll coating, spray coating, immersion coating, transfer coating, gravure coating, and the like. The binder weight as a percentage of the total article weight for articles within this aspect of the invention may range from about 5% to about 95%, preferably from about 10% to about 60%, more preferably 20 to 40%.
For preparing syndiotactic PVA, vinyl trihaloacetoxy monomers are commonly employed, such as, vinyl trifluoroacetate, trifluoroacetoxyethyl acrylate, trifluoroacetoxyethyl methacrylate, and the like.
Polyvinyl trifluoroacetate is a preferred precursor ester for preparation of syndiotactic polyvinyl alcohol used in practice of the invention due to its high chemical reactivity making conversion to polyvinyl alcohol relatively facile. It may be hydrolyzed with alcoholic alkali, but is preferably hydrolyzed with methanolic ammonia (see Example 64 below). Polyvinyl trifluoroacetate is readily prepared by polymerization of vinyl trifluoroacetate.
Optionally, small amounts (i.e., less than about 5 wt. %) of additional monomers may be incorporated in the parent polymer to improve various properties of the polyvinyl alcohol derived therefrom. A particularly preferred syndiotactic PVA (and used in Examples 65-91 below) is hydrolyzed poly(vinyl trifluoroacetate-co- 3-allyl-2,2'-dihydroxy-4,4'-dimethoxybenzophenone!) (99.95:0.05 by weight, abbreviated as PVTFA). The triad syndiotacticity measured by 1 H NMR was 51%, isotacticity=7%, atacticity=42%.
The syndiotacticity of the polyvinyl alcohol binder employed in this aspect of the invention typically and preferably ranges from about 45% to 100% syndiotacticity. It is known that increasing syndiotacticity at constant degree of polymerization results in increased melting point for the gel. (See Matsuzawa, S. et al., "Colloid Poly. Sci. 1981", 259(12), pp. 1147-1150.) For this reason higher syndiotacticity is preferred since mechanical strength and thermal stability are improved, but aqueous compositions of polyvinyl alcohol become more viscous and/or thixotropic as syndiotacticity increases due to gel formation. For these reasons, and owing to methods of preparation, the preferred range of syndiotacticity when coated from aqueous compositions preferably ranges from about 25 to about 65% syndiotacticity.
Although detrimental to the flexibility of the nonwoven articles of the invention, it may be advantageous to incorporate a small amount (e.g., up to about 10 mole %) of a chemical crosslinker such as those mentioned above in order to eliminate washout of the binder during use. Preferred crosslinkers are the above-mentioned titanates, with dialdehydes and the like being suitable but less preferred for ecological reasons.
The nonwoven articles of this aspect of the invention may be calendered at elevated temperature as above-described to reduce lint on the surface of the article and provide a smooth surface for printing. Embossing of a textured pattern onto the wipe may be performed simultaneously with calendering, or in a subsequent step. In addition, the above-mentioned colorants, softeners, fragrances, fillers, and the like may be employed.
4. Particularly Preferred Articles and Methods
Referring now to the drawing figures, FIG. 1 illustrates a perspective view of an absorbent nonwoven article 10 made in accordance with the invention. Article 10 has a plurality of fibers 12 at least partially coated with binder.
FIG. 2 is a cross-sectional view of the article of FIG. 1 taken through the section 2--2 of FIG. 1. FIG. 2 illustrates a preferred article wherein the major surfaces 14 and 16 (illustrated in exaggerated thickness) are comprise a combination of calendered and fused organic fibers and binder. Surfaces 14 and 16 form a sandwich with nonwoven material 18.
FIG. 3 illustrates a preferred method of producing the nonwoven articles illustrated in FIGS. 1 and 2. Staple fibers are fed via a hopper 20 or other means into a carding station 22, such devices being well known and not requiring further explanation. A moving conveyer transports a carded web 26 from carding station 22, typically to a crosslapper, not shown, which forms a layered web having fibers at various angles to machine direction. Carded web 26 then typically and preferably passes through a needling station 28 to form a needled web 30 which is passed through calender station 32. At this point the calendered web 34 is not more than about 60 mils (1.524 mm) thick. Calendered web 34 then passes through an immersion bath 36 where an aqueous binder precursor composition 37 is applied. Web 34 passes under rollers 38 and emerges as a coated web 40, which then passes through a drying station 42 to form a dried web 44. Drying station 42 typically and preferably exposes the web to a temperature and for a residence time which allows substantially all of the water to be removed from the binder precursor to form a dried web 44.
Depending on the composition of the binder precursor, type of crosslinking and/or bonding agent used, amount of water present, etc., web 44 may be suitable for use without further curing. In some embodiments, it is desirable to pass dried web 44 through a final curing station 46, which is at a temperature higher than the temperature of drying station 42, to form a dried and cured web 48.
Web 48 may then be passed through another set of calender rollers 50, which may used to emboss a pattern, fuse the surfaces, and impart other qualities to the article. Web 52 generally has a thickness of no more than 60 mils (1.524 mm), and a weight ranging from about 50 g/m 2 to about 250 g/m 2 .
Web 52 may then pass through a second needling station 54 to perforate the web for decorative or other purposes, after which the web is slit and wound onto take-up roll 56.
The features of the various aspects of the invention will be better understood in reference to the following Test Methods and Examples, wherein all parts and percentages are by weight. Names of ingredients in quotation marks indicate trade designations.
Test Methods
Tensile Strength
Tensile strength measurements were made on 1×3 inch (2.54×7.62 cm) wringer damp, die cut samples using an Instron Model "TM", essentially in accordance with ASTM test method D-5035. A constant rate of extension (CRE) was employed, and jaws were clamp-type.
Rate of jaw separation was 9.3 inches/min. (23.6 cm/min).
Elmendorf Tear
Elmendorf tear tests were conducted on 2.5×11 inch (6.35×27.94 cm) damp, die-cut, notched (20 mm) samples, essentially in accordance with ASTM D-1424, using an Elmendorf Tear Tester model number 60-32, from Thwing-Albert Co., with a 3200 gram pendulum. An average of four measurements was used. A high value is desired.
Absorption
Absorption measurements were made on 6×8 inch (15.24×20.32 cm) samples which were die-cut in damp conditions. The absorption measurements are reported using the following terms:
(a) Dry Weight=the dried weight of the sample, in grams.
(b) No Drip Weight=the maximum total weight of the sample and water absorbed, in grams.
(c) With Drip Weight=the total weight of the sample, in grams, after dripping for 60 seconds.
(d) Damp Weight=the weight of the sample after passing through nip rollers.
(e) Wet Out=the time it takes for a droplet of water placed on the wipe surface to be completely absorbed into the sample.
(f) % Weight (H 2 O) Loss=(No Drip Weight--With Drip Weight)/No Drip Weight.
(g) Grams Water Absorbed per Square foot (grams/929 cm 2 )=3× (No Drip Weight--Dry Weight).
(h) Grams Water Absorbed per Gram Dry Weight=(No Drip Weight--Dry Weight)/Dry Weight.
(i) MD=machine direction, CD=cross direction, "abs"=absorbed, and "eff"=effective
(j) effective water absorption=3× (no drip weight--damp weight).
Materials Description
The materials are used in the examples which follow:
"R1130" is the trade designation for a copolymer of vinyl silane and vinyl acetate containing from about 0.5 to about 1.0 molar % of the silyl groups as vinylsilane units, a degree of polymerization of about 1700, and degree of hydrolysis of the vinyl acetate units preferably of 99+% (Kuraray Chemical KK, Japan). "Tyzor LA" is the trade designation for dihydroxybis(ammonium lactato) titanium (50 wt. % aqueous solution, available from du Pont Company, Du Pont Company), glyoxal (40 wt. % aqueous solution, Aldrich Chemicals) are then added to the silanol modified PVA solution at various proportions and combinations as described in the examples to follow.
"Tyzor 131" is the trade designation for a mixture of titanium orthoester complexes (20 wt. % aqueous solution, also available from DuPont.
"Nalco 8676" is the trade designation for a nanoscale, amorphous aluminum hydrous oxide colloid (10 wt. % aqueous solution), available from Nalco Chemical Company.
glyoxal is a dialdehyde of formula HCOCOH, available as a 40 wt. % aqueous solution from Aldrich Chemicals, Co.
"Airvol 165" is the trade designation for a 99.5+% hydrolyzed polyvinyl alcohol from Air Products and Chemicals, Inc.
EXAMPLES
General Procedure I for Preparing Inventive Articles
Nonwoven webs consisting of a blend of polyvinyl alcohol and rayon fibers (45% polyvinyl alcohol fiber having 1.5 denier and a length of 1.5 inch (3.81 cm) purchased from Kuraray, Japan, and 55% rayon fiber having 1.5 denier and a length of 1 and 9/16 inch (3.97 cm) purchased from BASF) were made using a web, making machine known under the trade designation "Rando-Webber". The resultant web had a nominal basis weight of 11.5 g/ft 2 (123.8 g/m 2 ) and an average thickness of 0.052 inch (0.132 cm).
Silanol modified polyvinyl alcohol granules ("R1130") were added to deionized water in proportions up to 10 wt. % solid in a stirred flask. The flask was then heated to 95° C. until reflux condition is achieved. The polymeric solution was then kept at reflux for a minimum of 45 minutes with adequate mixing. The solution was then cooled down to room temperature (about 25° C.). The silanol modified PVA solution was then diluted to 2.5 wt. % solid. Reactants such as Nalco 8676, Tyzor LA, Tyzor 131, and glyoxal were then added to the silanol modified PVA solution at various proportions and combinations as described in the examples to follow.
A 12×15 inch (30.48×38.1 cm) piece of this nonwoven web was placed in a pan and saturated with approximately 200 g of an aqueous coating solution containing 5.00 g of total polymer.
Saturated samples were then dried and cured in a flow-through oven at various conditions to be described in the examples below. When curing was completed, the samples were conditioned for 60 minutes in 60°-80° F. (140°-176° C.) tap water then dried. Samples were then analyzed for hydrophilicity, water retention and absorption, tensile strength, tear strength, and dry wiping properties.
Examples 1-10 and Comparative Example A
The results of testing on Comparative Example A, a nonwoven wipe originally 59 mils (0.149 cm) thick, and known under the trade designation "Brittex-11" (available from Vileda, a division of Freudenberg Co., Germany, and which is a PVA web coated with a PVA binder crosslinked with formaldehyde) were as follows:
Wet Out=3 sec.;
% Water Loss=12.8;
Total Water Absorption=137.5 g/ft 2 (1479 g/m 2 );
g of water absorbed/g of wipe=7.9;
tensile strength (machine direction)=273 lbs/in 2 (1882 KPa);
tensile strength (cross direction)=203 lbs/in 2 (1399 KPa);
Elmendorf Tear strength (machine direction and damp)=86;
Elmendorf Tear strength (cross direction and damp)=100+.
The test results for the inventive nonwovens of Examples 1-10 are presented in Tables 1 and 2. The nonwovens of Examples 1-10 were prepared as described in General Procedure I. For each example, 200 g of the polymeric solution (2.5 wt. % of R1130) was added with the reactants described below along with 0.1 g of Orcabrite Green BN 4009 pigment. The wt. % designated below represents the wt. % of active reactant (solid) over the R1130 polymer. The coated samples were dried at 150° F. (65.5° C.) for 2 hrs. then 250° F. (121.1° C.) for 2 hrs. and finally cured at 300° F. (148.8° C.) for 10 minutes. All samples had excellent dry wiping properties, low drag, and good feel.
TABLE 1______________________________________ g H2OSample Wet out abs/g of g H2O % H2OEx. #Description (sec) Dry wipe abs/(ft.sup.2) Loss______________________________________1 Uncoated 0 11.37 148.7 24.78nonwovensubstrateCOMPARATIVE2 R1130 0 8.90 158.6 18.553 R1130/0.5 wt. % 0 8.37 159.7 17.2Nalco 8676/5 wt. %Tyzor 1314 R1130/0.5 wt. % 0 7.46 145.7 21.2Nalco 8676/15 wt. %Tyzor 1315 R1130/0.5 wt. % 0 8.42 150.3 15.95Nalco 8676/5 wt. %Tyzor LA6 R1130/0.5 wt. % 0 7.79 155.9 16.73Nalco 8676/15 wt. %Tyzor LA7 R1130/5 wt. % 0 8.26 145.5 15.71Tyzor 1318 R1130/15 wt. % 0 7.83 150.4 17.11Tyzor 1319 R1130/5 wt. % 0 8.52 151.1 16.47Tyzor LA10 R1130/15 wt. % 0 8.06 136.6 12.93Tyzor LA______________________________________
TABLE 2______________________________________ Tensile Strength (KPa) Elmendorf TearEx. #Sample Description MD CD MD CD______________________________________1 Uncoated nonwoven 1289 641 74.7 56.3substrateCOMPARATIVE2 R1120 2126 2011 85.5 93.03 R1130/0.5 wt. % 2555 2012 95.0 88.0Nalco 8676/5 wt. %Tyzor 1314 R1130/0.5 wt. % 2770 2032 86.3 100Nalco 8676/15 wt. %Tyzor 1315 R1130/0.5 wt. % 2543 2001 76.7 85.0Nalco 8676/5 wt. %Tyzor LA6 R1130/0.5 wt. % 2802 1921 90.3 100Nalco 8676/15 wt. %Tyzor LA7 R1130/5 wt. % 2481 2155 77.0 84.5Tyzor 1318 R1130/15 wt. % 2327 2201 90.8 84.0Tyzor 1319 R1130/5 wt. % 2356 1787 80.3 82.5Tyzor LA10 R1130/5 wt. % 2769 2090 78.0 87.5Tyzor LA______________________________________
Examples 11-20
The wipes of Example 11-20 were prepared as described in General Procedure I, and dried and cured as in Examples 1-10, except that the final 10 minute cure at 300° F. (121.1° C.) was eliminated. The absorbency, tensile strength and tear test results are presented in Tables 3 and 4.
It can be seen comparing the data of Tables 3 and 4 with the data of Tables 1 and 2 that addition of Tyzor LA or Tyzor 131, and the final 121.1° C. cure, gave immediate wet-out and consistently higher tensile strength and Elmendorf tear values.
TABLE 3______________________________________ g H2OSample Wet out abs/g of g H2O % H2OEx. #Description (sec) dry wipe abs/(ft.sup.2) Loss______________________________________11 R1130/0.5 wt. % 28 8.87 152.8 17.7Nalco 867612 R1130/1 wt. % 60+ 7.80 141.5 14.09Nalco 867613 R1130/1.5 wt. % 60+ 7.65 141.7 13.99Nalco 867614 R1130/2.0 wt. % 60+ 7.48 138.7 14.92Nalco 867615 R1130/0.5 wt. % 0 8.35 160.7 19.60Nalco 8676/1 wt. %Tyzor LA16 R1130/0.5 wt. % 0 8.49 161.5 19.70Nalco 8676/5 wt. %Tyzor LA17 R1130/0.5 wt. % 0 8.31 155.6 16.57Nalco 8676/10 wt. %Tyzor LA18 R1130/0.5 wt. % 0 8.49 164.2 18.63Nalco 8676/1 wt. %Tyzor 13119 R1130/0.5 wt. % 0 8.12 165.0 19.69Nalco 8676/5 wt. %Tyzor 13120 R1130/0.5 wt. % 0 8.61 164.8 21.33Nalco 8676/10 wt. %Tyzor 131______________________________________
TABLE 4______________________________________ Tensile Strength (KPa) Elmendorf TearEx. #Sample Description MD CD MD CD______________________________________11 R1130/0.5 wt. % 2218 2022 91.7 85.0Nalco 867612 R1130/1 wt. % 2212 1856 88.8 100.0Nalco 867613 R1130/1.5 wt. % 2678 1948 83.3 90.0Nalco 867614 R1130/2.0 wt. % 2961 2164 86.3 100.0Nalco 867615 R1130/0.5 wt. % 2425 1783 78.3 100.0Nalco 8676/1 wt. %Tyzor LA16 R1130/0.5 wt. % 2182 2086 74.5 100.0Nalco 8676/5 wt. %Tyzor LA17 R1130/0.5 wt. % 2379 2130 100.0 95.0Nalco 8676/10 wt. %Tyzor LA18 R1130/0.5 wt. % 2390 1959 90.3 92.0Nalco 8676/1 wt. %Tyzor 13119 R1130/0.5 wt. % 2295 1904 85.0 100.0Nalco 8676/5 wt. %Tyzor 13120 R1130/0.5 wt. % 2419 1837 78.0 100.0Nalco 8676/ 10 wt. %Tyzor 131______________________________________
Examples 21-27
The inventive nonwovens of Examples 21-27 were red as described in General Procedure I. For each sample, 200 g of the polymeric solution (2.5 wt. % of R1130) was mixed with 1.54 g of glyoxal (40 wt. % aqueous solution) and 0.25 g of NH 4 Cl and then reacted with the reactants described below. The wt. % designated below represents the wt. % of active reactant (solid) over the R1130 polymer. The coated samples were dried at 110° F. (92.2° C.) for 4 hrs. All samples had excellent dry wiping properties, low drag, and good feel. The results of the absorbency, tensile strength, tear strength are presented in Tables 5 and 6.
TABLE 5______________________________________ g H2OSample Wet out abs/g of g H2O % H2OEx. #Description (sec) Dry wipe abs/(ft.sup.2) Loss______________________________________21 NONE: 0 7.40 127.9 15.27COMPARATIVE22 1 wt. % 60+ 8.86 157.1 24.28Nalco 867623 3 wt. % 60+ 9.39 162.9 26.12Nalco 867624 5 wt. % 60+ 8.03 139.3 23.10Nalco 867625 1 wt. % 31 8.25 148.7 19.70A12 (SO4) 3(100% solid)26 3 wt. % 16 8.53 153.8 21.82A12 (SO4) 3(100% solid)27 5 wt. % 60+ 8.54 147.1 21.32A12 (SO4) 3(100% solid)______________________________________
TABLE 6______________________________________ Tensile Strength (KPa) Elmendorf TearEx. #Sample Description MD CD MD CD______________________________________21 NONE: 1717 2616 100.0 86.3COMPARATIVE22 1 wt. % 1693 2639 94.0 94.3Nalco 867623 3 wt. % 2509 1915 -- 91.0Nalco 867624 5 wt. % 2248 3230 100.0 90.3Nalco 867625 1 wt. % 1880 2202 100.0 82.7A12 (SO4) 3(100% solid)26 3 wt. % 1813 2273 100.0 85.0A12 (SO4)3(100% solid)27 5 wt. % 2449 2030 100.0 96.0A12 (SO4) 3(100% solid)______________________________________
Examples 28-29
Examples 28-29 demonstrated the use of nonwoven web containing 100% PVA fibers. The nonwoven web was made from 100% PVA fibers which were 1.5 denier and 1.5 inch long (3.81 cm), purchased from Kuraray, Japan, with a basis weight of 7.0 g/ft 2 (75.3 g/m 2 ) using a carding machine known under the trade designation "Rando-Webber." A 12×15 inch (30.48×38.1 cm) sample of this web was coated with a solution containing: 130 g of R1130 solution (2.5 wt. % solid), 0.16 g of Nalco 8676 (10% solid), 1.63 g of Tyzor 131 (20 wt. % in water), and 0.16 g of Orcobrite Royal blue pigment # R2008. The coated sample was dried at 150° F. (65° C.) for 2 hrs. then cured at 300° F. (148.9° C.) for an additional 15 minutes. The coated sample had a rubbery feel. The absorbency and tensile strength data are presented in Tables 7 and 8.
TABLE 7______________________________________ g H2OSample Wet out abs/g of g H2O % H2OEx. #Description (sec) dry wipe abs/(ft.sup.2) Loss______________________________________28 Uncoated 0 12.74 159.3 30.71100% PVA fiber webCOMPARATIVE29 Coated 100% 7 4.74 81.3 13.32PVA fiber web______________________________________
TABLE 8______________________________________ Tensile Strength (KPa)Ex. # Sample Description MD CD______________________________________28 Uncoated 100% PVA fiber web 1751 2042 COMPARATIVE29 Coated 100% PVA fiber web 2752 2352______________________________________
Examples 30-31
Examples 30-31 demonstrated the use of a nonwoven web containing a blend of PVA and cotton fibers. The nonwoven web was made from 50 wt. % PVA fibers which were 1.5 denier and 1.5 inch (3.81 cm) in length, purchased from Kuraray, Japan, and 50 wt. % cotton fibers with a resultant basis weight of 5.5 g/ft 2 (59.2 g/m 2 ) using a web making machine known under the trade designation "Rando-Webber." A 12×15 inch (30.48×38.1 cm) sample of this web was coated with a solution containing: 110 g of R1130 solution (2.5 wt. % solid in H 2 O), 0.13 g of Nalco 8676 (10% solid in H 2 O), 1.38 g of Tyzor 131 (20% solid in H 2 O), and 0.14 g of Orcobrite Royal blue pigment # R2008. The coated sample was dried at 150° F. (65.5° C.) for 2 hours, then cured at 300° F. (148.9° C.) for an additional 15 minutes. The coated sample had excellent dry wiping properties, low drag, and good feel. The absorbency and tensile strength data are presented in Tables 9 and 10.
TABLE 9______________________________________ g H2OSample Wet out abs/g of g H2O % H2OEx. #Description (sec) Dry wipe abs/(ft) Loss______________________________________30 Uncoated 50/50 0 22.27 170.4 50.16blend of PVA/Cotton fibers web:COMPARATIVE31 Coated 50/50 4 5.82 57.7 17.41blend of PVA/Cotton fibers web______________________________________
TABLE 10______________________________________ Tensile Strength (KPa)Ex. # Sample Description MD CD______________________________________30 Uncoated 50/50 blend of PVA/ 384 411 Cotton fibers web: COMPARATIVE31 Coated 50/50 blend of PVA/ 3689 2919 Cotton fibers web______________________________________
Example 32
The nonwoven web used in Example 32 was made from 100% rayon fibers which were 3.0 denier and 2.5 inches (6.35 cm) long from Courtalds Chemical Company, England, using a carding/crosslap/needletacking process. Its basis weight was 16.2 g/ft 2 (174.3 g/m 2 ). A 15×15 inch sample of this web (38.1×38.1 cm) was coated with a solution containing: 250 g of R1130 solution (2.5% solid in H 2 O), 0.31 g of Nalco 8676 (10% solid in H 2 O), 3.13 g of Tyzor 131 (20 wt. % in H 2 O), and 0.4 g of Orcobrite Royal blue pigment # R2008. The coated sample was dried at 150° F. (65.5° C.) for 2 hours and then at 250° F. (121.1° C.) for 2 hours, and finally at 300° F. (148.8° C.) for an additional 10 minutes. The coated sample had excellent dry wiping properties, low drag, and soft feel.
Example 33
Example 33 demonstrated the preparation of a bactericidal wipe based on iodine and the polyvinyl alcohol/polyiodide complex. A solution of 1.2 g potassium iodide, 0.64 g iodine crystals, and 50 g of water was prepared. This solution was then saturated on a wipe prepared using the procedure of Example 5. Initially, a brown color was observed where the sample had been treated. The brown color gradually changed to blue color which is a characteristic of the polyvinyl alcohol/polyiodide complex. When rinsed with water, iodine color and odor were plainly evident.
General Procedure II for Preparing Inventive Articles
Nonwoven webs consisting a blend of polyvinyl alcohol and rayon fibers (45% polyvinyl alcohol fiber having a denier of 1.5 and a length of 1.5 inch (3.81 cm) purchased from Kuraray KK, and 55% rayon fiber having a denier of 1.5 and a length of 1 and 9/16 inch (3.97 cm) purchased from BASF) were made using a web making machine known under the trade designation Rando-Webber. The resultant web had an average dry weight of 12 g/ft 2 (129 g/m 2 ) and nominal thickness of 0.056 inch (0.142 cm).
An aqueous binder precursor solution was prepared for each example containing various amounts of Airvol 165 (a 99.8% hydrolyzed polyvinyl alcohol with molecular weight 110,000 and degree of polymerization 2500, obtained from Air Products) reacted with Tyzor LA and/or Tyzor 131 and optionally, glyoxal as described in Examples 34-47 and NH 4 Cl, an acid catalyst. The binder precursor solutions also may have contained optional crosslinker(s) and pH modifiers as detailed in the Examples. A 12×15 inch (30.48×38.1 cm) piece of this nonwoven web was placed in a pan and saturated with approximately 200 g of an aqueous coating solution containing 5.00 g of total polymer.
Saturated samples were dried in a flow-through oven at 150° F. (65.5° C.), for between 30 minutes and 4 hours, and cured in a flow-through oven, preferably for greater than 10 minutes, at temperatures greater than 220° F. (104° C.). The samples were flipped every 10-30 minutes to aid in even drying conditions. When curing was completed, the samples were conditioned for 60 minutes in 60°-80° F. (15.6°-26.7° C.) tap water then dried. Samples were then analyzed for hydrophilicity, water retention and absorption, tensile strength, tear strength, and dry wiping properties.
Examples 34-38
Examples 34-38 illustrated the advantages of employing a titanate crosslinked PVA binder in wiping articles according to the invention. The wipes of Examples 34-38 were prepared as described in General Procedure II with the compositions described below at an initial coating weight of 5 g of polymeric material per 200 g solution and dried slowly at 150° F. (65.5° C.), followed by curing at 300° F. (148.9° C.). The absorbency, tensile strength, and tear data are presented in Tables 11 and 12, respectively.
TABLE 11______________________________________ H.sub.2 OEx. Wet Out % H.sub.2 O g H.sub.2 O Abs/Dry Eff g# Description (sec.) Loss abs./ft.sup.2 wgt. (g/g) H.sub.2 O/ft.sup.2______________________________________34 Airvol 165 0 20.49 157.62 8.20 116.22 without Titanate35 Airvol 165 0 17.52 149.55 7.95 109.86 with 5% Tyzor LA36 Airvol 165 0 13.10 142.83 7.51 101.49 with 15% Tyzor LA37 Airvol 165 0 18.89 144.96 7.77 106.56 with 5% Tyzor 13138 Airvol 165 0 15.79 133.47 7.21 96.06 with 15% Tyzor 131______________________________________
TABLE 12______________________________________ Av. Tensile Stress Elmendorf Tear (KPa) (Damp)Ex. # Description Machine Cross Machine Cross______________________________________34 Airvol 165 2489 1999 100+ 88 without Titanate35 Airvol 165 2916 2330 100+ 89 with 5% Tyzor LA36 Airvol 165 2985 2489 83 96 with 15% Tyzor LA37 Airvol 165 2930 2296 86 93 with 5% Tyzor 13138 Airvol 165 3103 2530 75 88 with 15% Tyzor 131______________________________________
Examples 39-45
Examples 39-45 illustrated the advantages of employing a titanate, and optionally, glyoxal crosslinked PVA binder in wiping articles according to the invention. The wipes of Examples 39-45 were prepared at an initial coating weight of 5 g total PVA, 1.59 g glyoxal, and 0.25 g NH 4 Cl per 200 g solution and dried slowly at 150° F. (65.5°). The absorbency, tensile strength, and tear data are presented in Tables 13 and 14, respectively.
TABLE 13______________________________________ H.sub.2 OEx. Sample Wet Out % H.sub.2 O g H.sub.2 O Abs/Dry Eff g# Description (sec.) Loss Abs./ft.sup.2 wgt. (g/g) H2O/ft.sup.2______________________________________39 Airvol 165 1 14.47 125.37 7.42 88.11 with Glyoxal, NH4Cl, w/out Titanate40 Airvol 165 1 14.91 124.62 7.39 87.81 with Glyoxal, NH4Cl, and 1% Tyzor LA41 Airvol 165 1 14.65 128.88 7.34 92.64 with Glyoxal, NH4Cl, and 5% Tyzor LA42 Airvol 165 1 14.75 130.53 7.35 93.33 with Glyoxal, NH4Cl, and 10% Tyzor LA43 Airvol 165 1 to 25 13.83 121.05 7.34 84.36 with Glyoxal, NH4Cl, and 1% Tyzor 13144 Airvol 165 1 to 20 15.27 128.61 7.48 91.23 with Glyoxal, NH4Cl, and 5% Tyzor 13145 Airvol 165 1 14.58 121.92 7.27 83.97 with Glyoxal, NH4Cl, and 10% Tyzor 131______________________________________
TABLE 14______________________________________ Av. Tensile Stress Elmendorf Tear PVA (KPa) (Damp)Ex. #Description Retention Machine Cross Machine Cross______________________________________39 Airvol 165 80.5 2482 2255 98 100+with Glyoxal,NH4Cl, w/outTitanate40 Airvol 165 83 2709 2193 86 100with Glyoxal,NH4Cl, and1% Tyzor LA41 Airvol 165 91.2 2592 2055 86 96with Glyoxal,NH4Cl, and5% Tyzor LA42 Airvol 165 91.9 2758 2034 88 95with Glyoxal,NH4Cl, and10% Tyzor LA43 Airvol 165 78.2 2696 2455 97 100+with GlyoxalNH4Cl, and1% Tyzor 13144 Airvol 165 86.1 2772 2392 94 100+with Glyoxal,NH4Cl, and5% Tyzor 13145 Airvol 165 75.1 2558 2310 100+ 100+with Glyoxal,NH4Cl, and10% Tyzor 131______________________________________
Example 46
Example 46 demonstrated the ability to color the wiping articles of this invention made in accordance with General Procedure II in varying colors and shades. A binder binder precursor solution was prepared consisting of 100 g 5 wt. % Airvol 165, 1.68 g Tyzor LA, 0.03 g, 0.06 g, 0.13 g, 0.25 g, or 0.5 g pigment dispersion, and deionized water to achieve a total solution weight of 200 g for each run. The binder precursor solution was coated onto a 12×15 inch (30.48 cm×38.1 cm) piece of PVA/rayon nonwoven produced as described in General Procedure II, dried at 120° F. (48.9° C.) for 2 hours, and finally cured for one hour at 140° F. (57.0° C.). Upon completion of run, the samples were conditioned for 60 minutes in 60°-80° F. (140°-176° C.) water and dried. Results are shown below.
______________________________________Pigment, Amount Results______________________________________"Orcobrite Red BN", 0.03 to 0.5 g Good color and fastness."Orcobrite Yellow 2GN", 0.03 to 0.5 g Good color and fastness."Orcobrite Green BN", 0.03 to 0.5 g Good color and fastness."Aqualor Green" Good color, binder washout."Aqualor Blue" Good color, binder washout.______________________________________
The aqueous pigment dispersions Known under the trade designation "Aqualor" were obtained from Penn Color (Doylestown, Pa), while those Known under the trade name "Orcobrite" aqueous pigment dispersions were obtained from Organic Dyestuffs (Concord, N.C.). Good results were obtained with a wide variety of the "Orcobrite" series of pigments. A major difference between the "Aqualor" and "Orcobrite" pigment dispersions, as supplied, was the substantially higher alkalinity of "Aqualor" pigment dispersions, perhaps leading to insufficient cure by the titanate crosslinking agent. Generally speaking it was found that the best results with regard to coloring were obtained at cure temperatures of 240°-250° F. (115.6°-121° C.), although higher temperatures were also useful.
Example 47
Example 47 demonstrated the ability to impregnate the synthetic wipes of the invention made in accordance with General Procedure II with a number of antibacterial, antifungal, and disinfecting solutions for use in the health care, business, and/or food service trades. A nonwoven produced in accordance with General Procedure II was saturated with an aqueous solution containing 1.2 g potassium iodide, 0.64 g solid iodine crystals, and 50 g deionized water.
Initially, a brown color was observed where the sample had been treated. The brown color gradually changed to blue, characteristic of the polyvinyl alcohol/polyiodide complex. When the article was rinsed with water, the iodine color and odor were plainly evident.
General Procedure III for Preparing Inventive Articles
A 12 by 15 inch (30.48×38.1 cm) piece of polyvinyl alcohol/rayon (45% polyvinyl alcohol fiber having a denier of 1.5 and a length of 1.5 inch (3.81 cm) purchased from Kuraray KK, and 55% rayon fiber having a denier of 1.5 and a length of 1 9/16 inch purchased from BASF) blended nonwoven fiber substrate (thickness=56 mil (0.142 cm), basis weight =11.5 g/ft 2 (123.8 g/m 2 ), prepared using a web marking of Rando-Webber) was placed in a pan and saturated with 200 g of an aqueous binder precursor solution containing 5.00 g total polyvinyl alcohol and polyacrylic acid, prepared by mixing a 5% aqueous solution of "Airvol 165" with a 2.5% aqueous solution of the polyacrylic acid. "Airvol 165" (a 99.8% hydrolyzed polyvinyl alcohol, MW=110,000, DP=2500 obtained from Air Products) was used in combination with polyacrylic acid (750,000 MW, Aldrich Chemical Co.). The binder precursor solution pH was adjusted with 85% phosphoric acid. The sample and tray were placed in a flow through drying oven at 120°-150° F. (48.9°-65.5° C.) for 2 hours followed by curing at 300° F. (148.9° C.) as specified in Table 15. The samples were flipped over after about 30 minutes and 60 minutes to aid in maintaining even drying. When curing was completed the samples were conditioned for 60 minutes in 60°-80° F. water then dried.
Examples 48-62
Example wipes 48-62 were made in accordance with General Procedure III at the conditions specified in Table 15, and subsequently analyzed for wet out, absorptivity, tensile strength, tear strength, and dry wiping properties. The test results are presented in Tables 16-17. Examples 48-62 each contained 0.1 g "Orcobrite Yellow 2GN 9000" (a yellow pigment, available from Organic Dyestuffs, Corp.).
TABLE 15______________________________________ % Coating ConditionedEx. Cure Loss During Coat Wt.# Description Conditions Conditioning (g/m.sup.2)______________________________________48 Polyacrylic Acid, 2 HR 120° F. 4 40.5 pH = 3.0, (48.9° C.)/ COMPARATIVE 5 MIN 300° F. (148.9° C.)49 Airvol 165 2 HR 120° F. 1 48.4 (polyvinyl alcohol), (48.9° C.)/ pH = 3.0, 5 MIN 300° F. COMPARATIVE (148.9° C.)50 1 part 2 HR 120° F. 0 49.5 Polyacrylic acid/ (48.9° C.)/ 2 parts Airvol 165, 5 MIN 300° F. pH = 3.0 (148.9° C.)51 1 part 2 HR 120° F. 0 48.2 Polyacrylic acid/ (48.9° C.)/ 3 parts Airvol 165, 5 MIN 300° F. pH = 3.0 (148.9° C.)52 1 part 2 HR 120° F. 0 56.9 Polyacrylic acid/ (48.9° C.)/ 5 parts Airvol 165, 5 MIN 300° F. pH = 3.0 (148.9° C.)53 1 part 2 HR 120° F. 0 58.5 Polyacrylic acid/ (48.9° C.)/ 10 parts Airvol 165, 5 MIN 300° F. pH = 3.0 (148.9° C.)54 1 part 2 HR 150° F. 0 52.4 Polyacrylic acid/ (65.6° C.)/ 99 parts Airvol 165, 5 MIN 300° F. pH = 3.5 (148.9° C.)55 1 part 2 HR 150° F. 0 51.6 Polyacrylic acid/ (65.6° C.)/ 99 parts Airvol 165, 15 MIN 300° F. pH = 3.5 (148.9° C.)56 1 part 2 HR 150° F. 0 55.4 Polyacrylic acid/ (65.6° C.)/ 99 parts Airvol 165, 25 MIN 300° F. pH = 3.5 (148.9° C.)57 0.1 part 2 HR 150° F. 1 49.5 Polyacrylic acid/ (65.6° C.)/ 99 parts Airvol 165, 5 MIN 300° F. pH = 3.5 (148.9° C.)58 0.5 part 2 HR 150° F. 1 53.5 Polyacrylic acid/ (65.6° C.)/ 99 parts Airvol 165, 5 MIN 300° F. pH = 3.5 (148.9° C.)59 1 part 2 HR 150° F. 0 55.4 Polyacrylic acid/ (65.6° C.)/ 99 parts Airvol 165, 5 MIN 300° F. pH = 3.5 (148.9° C.)60 1 part 2 HR 150° F. 0 49.7 Polyacrylic acid/ (65.6° C.)/ 99 parts Airvol 165, 5 MIN 300° F. pH = 4.0 (148.9° C.)61 1 part 2 HR 150° F. 0 52.3 Polyacrylic acid/ (65.6° C.)/ 99 parts Airvol 165, 5 MIN 300° F. pH = 4.6 (148.9° C.)62 1 part 2 HR 150° F. 1 48.3 Polyacrylic acid/ (65.6° C.)/ 99 parts Airvol 165, 5 MIN 300° F. pH = 3.3 (148.9° C.)______________________________________
TABLE 16______________________________________ Tensile Tensile Strength Strength Elmendorf Elmendorf Machine Cross Web Tear Test Tear TestEx. Direction Direction (Machine (Cross Web % H.sub.2 O# (KPa) (KPa) Direction) Direction) Loss______________________________________48 1910 1014 65 73 1149 3054 2240 53 90 1150 2937 2420 54 100+ 1051 3296 2117 74 86 1152 2379 1751 87 100+ 1153 2779 1813 81 82 1354 2772 2737 96 100+ 1855 2958 2565 77 100+ 2056 2854 2399 79 90 2157 2758 2365 91 100+ 1658 2523 2324 88 100+ 1859 2723 2461 85 100+ 2060 2737 2392 89 100+ 2261 2785 2358 87 100+ 2262 2909 2275 90 100+ 19______________________________________
TABLE 17______________________________________Ex. Total H.sub.2 O Abs. H.sub.2 O Abs./Dry Eff. H.sub.2 O Abs.# (g/ft.sup.2) Wt. (g/g) (g/ft.sup.2)______________________________________48 175.7 9.70 105.249 137.7 7.70 98.950 142.7 7.63 101.151 139.4 7.27 94.552 126.2 6.13 84.953 136.3 6.67 96.354 158.7 7.78 114.055 157.0 8.03 111.456 156.0 7.46 111.157 148.6 7.41 105.058 159.7 7.86 115.359 160.9 8.31 116.760 158.7 8.55 116.161 162.1 8.21 118.362 150.8 7.76 108.7______________________________________
Example 63
This example demonstrated the preparation of a bactericidal wipe based on iodine and a polyvinyl alcohol/polyiodide complex, and made in accordance with General Procedure III. A solution of 1.2 g potassium iodide, 0.64 g iodine crystals, and 50 g water was prepared. This solution was coated onto a sample of 1:2 polyacrylic acid/polyvinyl alcohol wipe prepared as in General Procedure III above. Initially, a brown color was observed where the sample had been treated. The brown color gradually changed to blue characteristic of the polyvinyl alcohol/polyiodide complex. When rinsed with water iodine color and odor were plainly evident.
General Procedure IV for Preparing Inventive Articles
A 12 by 15 inch (30.48×38.1 cm) piece of polyvinyl alcohol/rayon (45% polyvinyl alcohol fiber having a denier of 1.5 and a length of 1.5 in (3.81 cm) purchased from Kuraray KK, and 55% rayon fiber having a denier of 1.5 and a length of 1.56 inch (3.96 cm) purchased from BASF) blended nonwoven fiber substrate (thickness=56 mil (0.142 cm), basis weight 11.5 g/ft 2 (123.8 g/cm 2 ), prepared using a web making machine known under the trade designation "Rando-Webber") was placed in a pan and saturated with 200 g of an aqueous binder precursor solution containing 5.00 g total polyvinyl alcohol. "Airvol 165" (a 99.8% hydrolyzed polyvinyl alcohol, MW=110,000, DP=2500 obtained from Air Products) was used in combination with syndiotactic polyvinyl alcohol prepared in Example 64 to comprise the polyvinyl alcohol content in Examples 65-91. The binder precursor solutions may also have contained optional crosslinker(s), and pH modifiers depending on the Example. The sample and tray were placed in a flow through drying oven at 120°-50° F. (48.9°-65.6° C.) for 3 to 4 hours as specified. The samples were flipped over after about 30 minutes and 60 minutes to aid in maintaining even drying. When curing was completed the samples were conditioned for 60 minutes in 60°-80° F. (15.6°-26.7° C.) water then dried. Samples were then analyzed for wet out, absorptivity, tensile strength, tear strength, and dry wiping properties, with the results reported in Tables 18-27.
Example 64
Preparation of Syndiotactic PVA
This example illustrated the preparation of syndiotactic polyvinyl alcohol employed in Examples 65-91.
The polyvinyl trifluoroacetate (PVTFA) copolymer described above (300 g) was dissolved in 700 g acetone. This solution was slowly added to 1700 g of 10% methanolic ammonia that had been cooled in ice to 15° C. Despite vigorous mechanical stirring a large ball of solid material formed on the stirrer blade making stirring ineffective. After addition was complete the ball of material was broken up by hand and the mixture was shaken vigorously. The process was repeated twice more (elapsed time was about 3 hr). The divided mass was vigorously mechanically stirred for 20 minutes and allowed to stand at room temperature overnight.
The supernatant liquid was decanted off leaving a mixture of white powder and yellow fibrils. The solids were collected by filtration and spread in a tray at 15.6° C. to evaporate residual solvent. The solids were collected when constant weight over 2 hr was achieved. The solid was chopped in a blender to give 87.3 g of beige powder, 92% yield, referred to hereinafter as "Syn". Analysis of this material was carried out using IR and 1 H NMR spectroscopy, and Gel Permeation Chromatography. The results indicated the likely presence of traces of trifluoroacetate esters and salts. The triad syndiotacticity measured by 1 H NMR in DMSO-d 6 was 33%, atacticity=50%, isotacticity=17%, The difference between the hydrolyzed polymer and the trifluoroacetate precursor polymer may be due to acid catalyzed epimerization of hydroxyl groups during drying or solution in boiling water.
Examples 65-70
Examples 65-70 illustrated the advantages of employing syndiotactic polyvinyl alcohol alone or in blends with atactic polyvinyl alcohol in wiping articles according to the invention. The articles were prepared at an initial coating weight of 5 g total PVA/200 g solution. Curing conditions were 4 hr at 48.9° C.
TABLE 18__________________________________________________________________________ Tensile Tensile Strength Strength % Coating Elmendorf Elmendorf Machine Cross Weight Loss Tear TearEx. Direction Direction During Machine Cross# Description (KPa) (KPa) Conditioning Direction Direc-tion__________________________________________________________________________65 100% 2061 1131 10.1 63(5) 95(7) AIRVOL 16566 99% 2186 1496 8.9 79(2) 100+ AIRVOL 165:1% Syn67 95% 2027 1427 8.4 74(7) 89(0) AIRVOL 165:5% Syn68 90% 2475 1799 7.8 75(4) 86(7) AIRVOL 165:10% Syn69 80% 2109 1510 6.2 100+ 95(4) AIRVOL 165:20% Syn70 100% Syn 2661 1979 5.5 100+ 91(0)__________________________________________________________________________
TABLE 19__________________________________________________________________________ Water Total Absorption/ Effective Water Dry wt. WaterEx. Wet Out % Water Absorption of Sample Absorption# Description (sec) Loss (g/ft.sup.2) (g/g) (g/ft.sup.2)__________________________________________________________________________65 100% AIRVOL 165 0 17.4 134.52 7.92 99.6066 99% AIRVOL 165: 0 20.0 150.09 8.38 112.50 1% Syn67 95% AIRVOL 165: 0 15.0 136.17 7.81 99.90 5% Syn68 90% AIRVOL 165: 0 14.8 130.50 7.63 95.40 10% Syn69 80% AIRVOL 165: 0 15.8 131.58 7.14 94.80 20% Syn70 100% Syn 2 16.8 143.25 7.33 106.71__________________________________________________________________________
Examples 71-83
These examples demonstrated the use of syndiotactic polyvinyl alcohol with chemical crosslinkers (Tyzor LA and/or glyoxal) in wiping articles according to the invention. Curing conditions were 3.5 hr at 150° F. (65.5° C.). Mole % crosslinking amounts for Tyzor LA were based on four bonds between titanium and polyvinyl alcohol. Mole % crosslinking amounts for glyoxal were based on four bonds between glyoxal and polyvinyl alcohol.
TABLE 20__________________________________________________________________________ Water Total Absorption/ Effective Water Dry wt. WaterEx. Wet Out % Water Absorption of Sample Absorption# Description (sec) Loss (g/ft.sup.2) (g/g) (g/ft.sup.2)__________________________________________________________________________71 1% Blend of Syn. 0 25.1 129.2 8.65 119.49 in Airvol 165 with 20 mol % Tyzor LA crosslinking72 1% Blend of Syn 0 20.1 137.4 8.12 117.36 in Airvol 165 with 20 mol % Tyzor LA crosslinking73 5% Blend of Syn 0 16.9 134.7 7.71 106.92 in Airvol 165 with 20 mol % Tyzor LA crosslinking74 5% Blend of Syn 0 17.8 135.2 7.62 108.00 in Airvol 165 with 20 mol % Tyzor LA crosslinking75 10% Blend of Syn 0 21.7 128.4 7.96 110.28 in Airvol 165 with 20 mol % Tyzor LA crosslinking__________________________________________________________________________
TABLE 21__________________________________________________________________________ Water Total Absorption/ Effective Water Dry wt. WaterEx. Wet Out % Water Absorption of Sample Absorption# Description (sec) Loss (g/ft.sup.2) (g/g) (g/ft.sup.2)__________________________________________________________________________76 10% Blend of Syn 0 18.2 133.8 7.70 108.2 in Airvol 165 with 20 mol % Tyzor LA crosslinking77 1% Blend of Syn 0 15.6 137.8 8.42 107.7 in Airvol 165 with 40 mol % Glyoxal crosslinking78 1% Blend of 0 17 139.4 8.58 111.4 Syndiotactic in Airvol 165 with 40 mol % Glyoxal crosslinking79 5% Blend of 0 15.8 145.4 8.35 114.7 Syndiotactic in Airvol 165 with 40 mol % Glyoxal crosslinking80 5% Blend of 0 17.3 139.7 8.80 113.3 Syndiotactic in Airvol 165 with 40 mol % Glyoxal crosslinking81 10% Blend of 0 11.2 144.5 8.40 107.1 Syndiotactic in Airvol 165 with 40 mol % Glyoxal crosslinking82 10% Blend of 0 16.9 154.8 8.30 122.3 Syndiotactic in Airvol 165 with 40 mol % Glyoxal crosslinking83 10% Blend of 0 13.1 141.9 7.46 105.2 Syndiotactic in Airvol 165__________________________________________________________________________
TABLE 22______________________________________ Tensile Strength % Coating Machine Tensile Weight LossEx. Direction Strength Cross During# Description (KPa) Direction (KPa) Conditioning______________________________________71 1% Blend of Syn 2158 2082 4.3 in Airvol 165 with 20 mol % Tyzor LA crosslinking72 1% Blend of Syn 2971 1724 4.2 in Airvol 165 with 20 mol % Tyzor LA crosslinking73 5% Blend of Syn 2572 2199 4.4 in Airvol 165 with 20 mol % Tyzor LA crosslinking74 5% Blend of Syn 2737 1979 4.5 in Airvol 165 with 20 mol % Tyzor LA crosslinking______________________________________
TABLE 23______________________________________ Tensile Strength % Coating Machine Tensile Weight LossEx. Direction Strength Cross During# Description (KPa) Direction (KPa) Conditioning______________________________________75 10% Blend of Syn 2475 1944 5.1 in Airvol 165 with 20 mol % Tyzor LA crosslinking76 10% Blend of Syn 2910 2240 4.8 in Airvol 165 with 20 mol % Tyzor LA crosslinking77 1% Blend of Syn 2820 1889 3.3 in Airvol 165 with 40 mol % Glyoxal crosslinking78 1% Blend of 2351 -- 3.5 Syndiotactic in Airvol 165 with 40 mol % Glyoxal crosslinking79 5% Blend of 2482 2006 3.2 Syndiotactic in Airvol 165 with 40 mol % Glyoxal crosslinking80 5% Blend of 2199 1841 3.5 Syndiotactic in Airvol 165 with 40 mol % Glyoxal crosslinking81 10% Blend of 2227 1696 3.5 Syndiotactic in Airvol 165 with 40 mol % Glyoxal crosslinking82 10% Blend of 2379 1786 3.0 Syndiotactic in Airvol 165 with 40 mol % glyoxal crosslinking83 10% Blend of 2365 1696 1.8 Syndiotactic in Airvol 165______________________________________
Examples 84-86
Examples 84-86 demonstrated the effect of coat weight on wiping parameters of articles made in accordance with General Procedure IV. A binder precursor solution consisting only of 30% syndiotactic PVA was coated onto nonwoven substrates at various coating weights (i.e., 1 g, 2 g, 5 g total PVA in coating solution) as indicated in Tables 24 and 25, which also present the absorbency and strength test results.
TABLE 24__________________________________________________________________________ Tensile Tensile % Weight Strength Strength Loss Elmendorf Elmendorf Machine Cross During Tear TearEx. Descrip- Direction Direction Condition- Machine Cross# tion (KPa) (KPa) ing Direction Direction__________________________________________________________________________84 5 g: 100% Syn 2661 ± 117 1979 ± 69 5.5 100+ 91 ± 085 2 g: 100% Syn 2006 ± 131 1351 ± 34 3.3 75 ± 6 96 ± 286 1 g: 100% Syn 1441 ± 138 1186 ± 89 2.9 84 ± 9 100+__________________________________________________________________________
TABLE 25__________________________________________________________________________ Water Total Absorption/ Effective Water Dry wt. WaterEx. Wet Out % Water Absorption of Sample Absorption# Description (sec) Loss (g/ft.sup.2) (g/g) (g/ft.sup.2)__________________________________________________________________________84 5 g: 100% Syn 2 16.8 143.25 7.33 106.7185 2 g: 100% Syn 0 18.2 146.31 8.31 116.4086 1 g: 100% Syn 0 20.5 157.68 10.43 127.62__________________________________________________________________________
Examples 87-89
Examples 87-89 demonstrated the results of direct ammonolysis of polyvinyl trifluoroacetate after the binder precursor solutions was coated on the nonwoven substrate. The absorbency and strength of these articles (Tables 26 and 27) were superior to those of 30% syndiotactic polyvinyl alcohol coated from water described in the preceding examples. One explanation of the benefits observed is that acid catalyzed loss of syndiotacticity was minimized by use of this method which probably provided greater surface area for ammonolysis.
TABLE 26______________________________________ Tensile Strength % Machine Tensile Weight LossEx. Direction Strength Cross During# Description (KPa) Direction (KPa) Conditioning______________________________________87 16 g 3744 3041 0 PVTFA/ammonolyzed (5 g PVA)88 6.5 g 2544 2082 0 PVTFA/ammonolyzed (2 g PVA)89 3.2 g 1551 1165 0 PVTFA/ammonolyzed (1 g PVA)______________________________________
TABLE 27__________________________________________________________________________ Water Total Absorption/ Effective Water Dry wt WaterEx. Wet Out % Water Absorption of Sample Absorption# Description (sec) Loss (g/ft.sup.2) (g/g) (g/ft.sup.2)__________________________________________________________________________87 16 g PVTFA/ 0 22.5 114.4 5.86 81.5 ammonolyzed (5 g PVA)88 6.5 g PVTFA/ 0 23.0 143.2 7.90 107.6 ammonolyzed (2 g PVA)89 3.2 g PVTFA/ 0 30.1 166.2 9.82 134.1 ammonolyzed (1 g PVA)__________________________________________________________________________
Example 90
This example demonstrated the preparation of a bactericidal wipe based on iodine and the polyvinyl alcohol/polyiodide complex utilizing General Procedure IV. A solution of 1.2 g potassium iodide, 0.64 g iodine crystals, and 50 g water was prepared. This solution was coated onto a sample of a wipe as prepared in Examples 84-86. Initially, a brown color was observed where the sample had been treated. The brown color gradually changed to blue characteristic of the polyvinyl alcohol/polyiodide complex. When rinsed with water iodine color and odor were plainly evident.
Example 91
A sample containing 5 g 30% syndiotactic PVA as the only binder component in 200 g total solution was prepared and coated as in Examples 84-86 containing 0.1 g "Orcobrite Blue 2GN" pigment (Organic Dyestuffs Corp., Concord, N.C.). The sample was cured at 250° F. (121° C.) for 2 hours. The sample discolored slightly and had a strong odor, but was colorfast after conditioning in luke-warm water for 2 hours.
Various modifications and alterations of this invention will become apparent to those skilled in the art without departing from the scope of the invention, and it should be understood that this invention is not to be unduly limited to the illustrated embodiments set forth herein.
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Nonwoven articles having high durability and absorbent-characteristics, and their methods of manufacture, are presented. One preferred article is characterized by
(a) a nonwoven web comprised of organic fibers comprised of polymers having a plurality of pendant hydroxyl groups; and
(b) a binder comprising an at least partially crosslinked and at least partially hydrolyzed polymeric resin having a plurality of pendant resin hydroxyl groups, the resin crosslinked by a crosslinking agent, the crosslinking agent selected from the group consisting of organic titanates and amorphous metal oxides, the polymeric resin derived from monomers selected from the group consisting of monomers within the general formula ##STR1## wherein: X is selected from the group consisting of Si(OR 4 OR 5 OR 6 ) and O(CO)R 7 ; and
R 1 -R 7 inclusive are independently selected from the group consisting of hydrogen and organic radicals having from 1 to about 10 carbon atoms, inclusive, and combinations thereof.
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[0001] This application is a Continuation of, and claims priority under 35 U.S.C. § 120 to, International Application number PCT/IB03/501866, by the inventors hereof, filed 21 May 2003, and claims priority to EPO application number 02405479.3, filed 11 Jun. 2002, the entireties of both of which are incorporated by reference herein.
BACKGROUND OF THE INVENTION
[0002] 1. Field of the Invention
[0003] This invention relates to a sealing arrangement for a rotor of a turbomachine. More particularly, but not exclusively, the invention relates to a sealing arrangement which can be used in the rotor of a gas turbine.
[0004] 2. Brief Description of the Related Art
[0005] It is a recognised problem that gases can leak from the flow channels formed by component parts, such as blade roots and heat shields, of a rotor in a turbomachine. The effects of such leakage will depend upon the type of turbomachine, but include: unnecessary heating, a loss of strength, mechanical failure, a loss of efficiency and a need for undesirably expensive materials.
[0006] It is well known to address the foregoing problems by the use of sealing elements, which often take the form of plates mounted between the component parts. In a typical arrangement, a portion of each plate is inserted into a slot made in the root part of a blade and another portion is inserted into a slot made in an adjacent heat shield.
[0007] Whilst such arrangements have been successful in reducing gas leakage, they suffer from a disadvantage that the slots in the adjacent component parts need to be provided at the same radial level and implementation of this precondition requires the component parts to be manufactured to within extremely narrow tolerances. It is further the case that the relative positions of the slots can change during operation of the turbomachine, due to the influences of high temperatures and centrifugal forces, with the effect that a plate can be subject to shear or to fracture.
[0008] To compensate for this mutual displacement of the slots, it is known to make the slots sufficiently wider than the thickness of the sealing plates. However, in this case, the plates are positioned in their slots with a significant skew and this results in unsatisfactorily high levels of leakage past the seal. When many joints are provided between individual sealing elements in the circumferential direction, the number of potential leakage paths tends to increase, with the effect that the problem is particularly exacerbated.
SUMMARY OF THE INVENTION
[0009] The present invention sets out to increase the effectiveness of seals between the component parts of the rotor of a turbomachine, as well as to allow a greater freedom of relative motion between these component parts.
[0010] Accordingly a first aspect of the invention provides a sealing arrangement for a rotor of a turbomachine.
[0011] Exemplarily, a first member and a first slot are each arranged so as to extend in both a substantially axial direction and a substantially circumferential direction when the rotor is assembled for use. Further exemplarily, a second and a third slot and second member are each arranged so as to extend in both a substantially radial direction and a substantially circumferential direction when the rotor is assembled for use.
[0012] In another exemplary embodiment, a sealing element is configured such that, when the rotor is assembled for use, the sealing element has a circumferential length which is substantially equal to the blade pitch of the said rotor or substantially equal to a multiple of the blade pitch of the said rotor.
[0013] The sealing element may be provided with a friction-reducing coating.
[0014] A second aspect of the invention provides a sealing element for a rotor of a turbomachine, the said sealing element defining a ring segment and being generally T-shaped in cross-section.
[0015] The sealing element may include a first member adapted for axial orientation within a rotor, when installed for use, and a second member adapted for radial orientation within a rotor, when installed for use. It may also be provided with a friction reducing coating.
[0016] According to a third aspect of the invention, there is provided a blade for a rotor of a turbomachine, the said blade including a blade root, the blade root being provided with a first and second slot which are adapted to extend substantially radially when the blade is installed in a rotor so as to accommodate a radially extending member of a sealing element, the first radial slot extends in a direction which is substantially opposite to a direction in which the said second radial slot extends.
[0017] According to a fourth aspect of the invention, there is provided a rotor for a turbomachine.
[0018] Exemplarily, each first member and each first slot are arranged so as to extend in both a substantially axial direction and a substantially circumferential direction. It can be further advantageous that each second and third slot and each second member are arranged so as to extend in both a substantially radial direction and a substantially circumferential direction when the rotor is assembled for use.
[0019] In another exemplary embodiment, each sealing element has a circumferential length which is substantially equal to the blade pitch of the said rotor or substantially equal to a multiple of the blade pitch of the said rotor.
[0020] Each sealing element may be provided with a friction-reducing coating.
[0021] The sealing elements may be advantageously positioned so that the circumferential positions of junctions between mutually adjacent sealing elements do not correspond with the circumferential positions of junctions between mutually adjacent blades and/or heat shields. In this regard, it can be particularly advantageous that the sealing elements are positioned such that there is a substantially maximum mismatch between the circumferential positions of junctions between mutually adjacent sealing elements and the circumferential positions of junctions between mutually adjacent blades and/or heat shields.
[0022] According to a fifth aspect of the invention, there is provided a process for the manufacture of a rotor for a turbomachine.
[0023] It can be advantageous that the first and/or second sealing elements are positioned so that the circumferential positions of junctions between mutually adjacent sealing elements do not correspond with the circumferential positions of junctions between mutually adjacent blades and/or heat shields.
[0024] It can also be advantageous that the first and/or second sealing elements are positioned such that there is a substantially maximum mismatch between the circumferential positions of junctions between mutually adjacent sealing elements and the circumferential positions of junctions between mutually adjacent blades and/or heat shields.
[0025] The provision of such slots and correspondingly configured projections on the sealing element provides two degrees of freedom, because the arrangement accommodates both axial and radial movement between adjacent component parts. This in turn allows the minimum gap at the connection between the components and sealing elements to be minimized, thereby leading to a more fluid-tight seal. It is further the case that centrifugal forces in the running engine contribute to the effect by pressing the sealing element against a side of the slot in which it is situated, thereby improving the tightness of the connection and the security of the seal still further. It is further the case that the relative characteristics of the blade, heat shield and sealing elements facilitate a highly efficient and effective manufacturing process.
BRIEF DESCRIPTION OF THE DRAWINGS
[0026] Embodiments of the invention will now be described by way of example and with reference to the accompanying drawings in which
[0027] FIG. 1 is a longitudinal section through a portion of a rotor containing a sealing arrangement in accordance with the invention;
[0028] FIG. 2 is a view corresponding to FIG. 1 and illustrating the manner in which the heat shield can be mounted on to the rotor; and
[0029] FIG. 3 is a partial cut-away view in the direction A of FIG. 2 .
[0030] The drawings show only the parts important for the invention. Same elements will be numbered in the same way in different drawings.
DETAILED DESCRIPTION OF EXEMPLARY EMBODIMENTS
[0031] FIG. 1 shows part of a rotor defining an embodiment of the invention. The arrangement includes a rotor shaft 1 , upon which are mounted a rotor blade 2 and heat shields 3 , 4 . This arrangement is replicated along the length of the rotor and around its circumference, however the following discussion will initially concentrate on the illustrated part for the sake of clarity.
[0032] Each heat shield 3 , 4 includes a root body portion 18 which is generally triangular in cross section, with radiussed corners. The slot 15 , 16 for accommodating the root body is correspondingly configured, but of larger dimensions, so that the root body portion 18 may rock, to a limited degree, in the axial direction within the slot 16 , as shown in FIG. 2 . The shape and configurations of the blade and heat shields and their respective root portions are generally complex, but known. For this reason, they will not be described further in detail. The portions of the structure which are predominantly significant in defining this embodiment of the invention are illustrated in close-up form in FIG. 1 , to which reference is now directed.
[0033] The expansion gap between the blade 2 and each heat shield 3 , 4 is sealed by a respective sealing element 5 , 6 . Each sealing element is somewhat T-shaped in cross-section and arcuate to conform with the radius of curvature of the rotor at the radial location at which it is located during use. The sealing elements 5 , 6 may, therefore, be considered segments of a ring in which the cross-bar of the ‘T’ is aligned radially and the stem of the ‘T’ is aligned radially. In the assembled state illustrated in FIG. 1 , each sealing element 5 , 6 is accommodated within a respective radially and circumferentially extending slot 9 , 10 provided within the blade 2 and a respective axially and circumferentially extending slot 7 , 8 provided in the adjacent heat shield 3 , 4 . To conform with the slots, each sealing element is arranged with a respective radially extending member 13 , 14 provided in a respective one of the radially and circumferentially extending slots 9 , 10 , and a respective axially extending member 11 , 12 which is accommodated within a respective axially and circumferentially extending slot 7 , 8 .
[0034] The radial extent of each radially extending member 13 , 14 is less than the radial extent of the respective slot 9 , 10 in which it is contained. Similarly, the axial extent of each axially extending member 11 , 12 is less than the axial extent of the slot 7 , 8 in which it is accommodated. As a consequence of this configuration, relative radial movement between the blade 2 and the heat shields 3 , 4 can be accommodated by movement of the axially extending members 11 , 12 , within their respective slots 7 , 8 . Similarly, relative radial movement between the blade 2 and the heat shields 3 , 4 can be accommodated by movement of the radially extending members 13 , 14 within their respective radially extending slots 9 , 10 . The arrangement therefore has two degrees of freedom of movement, making it possible for the sealing elements 5 , 6 to take up any one of a range of intermediate positions between the slots 9 , 10 provided in the blade 2 and the slots 7 , 8 provided in the heat shields 3 , 4 both during assembly and in operation.
[0035] In order to reduce friction between the sealing elements and the contact surfaces of the slots in which they are provided, a friction-reducing surface coating can be applied to the sealing elements, or one or both of the slots, if desired.
[0036] Assembly of the rotor will now be described with reference to FIGS. 2 and 3 .
[0037] Initially, the first row of heat shields 3 (shown to left of FIG. 1 ) is mounted onto the rotor shaft 1 . The blades 2 are next mounted onto the rotor shaft 1 , and a gap corresponding to the pitchwise length L (two pitches, see FIG. 3 ) of a single sealing element is left at a predetermined position, although several such gaps could be left at different positions around the circumference, if preferred. It is furthermore not necessary for the pitch-wise length of the sealing elements to be two pitches, so in alternative embodiments, the gap could correspond with just a single blade or several blades, depending upon whichever length is chosen for the sealing element.
[0038] Each sealing element 5 to be fitted between the first row of heat shields 3 and the blades 2 , is installed via the gap. In this regard, the axially extending member 11 of the sealing element 5 is fitted into the respective axially extending slot 7 immediately adjacent the gap and then slid circumferentially in such a manner as to introduce its radially extending member 13 into the radially extending slot 9 of the first blade root that lies adjacent the gap. Once a sufficient number of sealing elements 5 to correspond with the number of installed blades 2 have been fitted, sealing elements 6 are attached to the opposite axial side of the row of blade 2 via the gap in a similar fashion, although there is no row of heat shields into which they should be fitted on this side of the row of blades 2 , at this point in time.
[0039] Because two blades 2 were omitted from the blade row in order to form the gap, the last sealing elements 5 , 6 still remain to be inserted into the blade root slots 7 , 8 of these omitted blades 2 . These sealing elements 5 , 6 are therefore fitted to the appropriate opposite sides of the omitted blades 2 using the respective radial slots 9 , 10 provided in these blades 2 and the resulting arrangement, which defines a completion assembly, is then fitted into the gap together. The sealing elements 5 , 6 on both sides of the blade row are subsequently moved to positions around the circumference wherein the gaps between adjacent blade platforms and the gaps between adjacent sealing elements have a maximum mismatch, so as to reduce leakage paths.
[0040] Finally, the second row of heat shields 4 (shown to the right of FIG. 1 ) is built by installing the heat shields 4 through respective local grooves 17 at one or more locations and moving them circumferentially to respective final positions. Once in position, each heat shield 4 is rocked towards the adjacent sealing element 6 as shown in FIG. 2 , so as to accommodate the axially projecting member 12 of the sealing element 6 in the axial slot 8 of the heat shield as it addresses it. If preferred, however, the heat shield 4 need not be couple with a single sealing element 6 in this way. This is because the ability to move the heat shields 4 circumferentially and the shapes of the axially projecting member 12 and the slots 8 together mean that the heat shield 4 may initially be coupled with more than one adjacent sealing element 6 and subsequently adjusted circumferentially; indeed, the coupling may even be effected before any circumferential movement of the heat shield 4 takes place.
[0041] Following the assembly of the second ring of heat shields 4 , the next row of blades can be fitted to the rotor shaft 1 and the above process repeated.
[0042] Although the above embodiment provides the axially extending slots in the heat shields and the radially extending slots in the blade roots, the reverse arrangement (with the axially extending slots in the blade roots and the radially extending slots in the heat shields) is equally viable. Furthermore, although the axially extending members of the sealing elements extend from halfway along the radially extending members in the foregoing embodiment, this need not be the case and other configurations may be particularly useful where there are constraints upon the locations of the slots in the heat shields and blade roots.
[0043] The ability to accommodate relative movement between the heat shields and blades results from the two degrees of freedom afforded by the arrangement rather than the precise orientation of the two directions of possible movement. It is therefore the case that the members of the sealing elements and the accommodating slots do not necessarily need to be aligned with the axial and radial directions.
[0044] Reference Numbers
[0045] Rotor shaft
[0046] Rotor blade
[0047] Heat shield
[0048] Heat shield
[0049] Sealing element
[0050] Sealing element
[0051] Slot
[0052] Slot
[0053] Slot
[0054] Slot
[0055] Member
[0056] Member
[0057] Member
[0058] Member
[0059] Slot
[0060] Slot
[0061] Groove
[0062] Root body portion
[0063] While the invention has been described in detail with reference to exemplary embodiments thereof, it will be apparent to one skilled in the art that various changes can be made, and equivalents employed, without departing from the scope of the invention. Each of the aforementioned documents is incorporated by reference herein in its entirety.
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A sealing arrangement for a rotor of a turbomachine includes a blade ( 2 ), a heat shield ( 3, 4 ) and a sealing element ( 5, 6 ) for sealing between the blade ( 2 ) and the heat shield ( 3, 4 ) when the blade ( 2 ), heat shield ( 3, 4 ) and sealing element ( 5, 6 ) are assembled for use in the rotor. The heat shield ( 3, 4 ) includes a first slot ( 7, 8 ) for accommodating a first member ( 11, 12 ) of the sealing element ( 5, 6 ), and a root portion of the blade ( 2 ) includes a second and third slot ( 9, 10 ) for accommodating a second member ( 13, 14 ) of the sealing element ( 5, 6 ). The first slot ( 7, 8 ) extends in a direction which is substantially mutually perpendicular to a direction in which the second and third slot ( 9 ) extends, and the first member ( 11, 12 ) extends in a direction which is substantially mutually perpendicular to a direction in which the second member ( 13, 14 ) extends.
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This is a continuation of copending application Ser. No. 07/500,063 now U.S. Pat. No. 5,154,680 filed on Mar. 27, 1990.
BACKGROUND OF THE INVENTION
This invention relates generally to an apparatus and method for monitoring waveforms, and more particularly, to an apparatus and method for noninvasively monitoring the blood pressure waveform in a blood vessel by detection of the deformation of a diaphragm placed over tissue covering the blood vessel.
Methods for accurately monitoring the .blood pressure waveform have been under investigation for some time. While invasive methods can provide accurate waveforms, the trauma caused the patient makes the technique undesirable in many cases. One such method involves the use of a fluid filled catheter inserted into the patient's artery. While accurate blood pressure measurements can be obtained by use of this method, the negative effects on the patient may, in many cases, outweigh the accuracy in results to be obtained by use of the method.
Another method to monitor a patient's blood pressure waveform is the widely used auscultatory method of Korotkoff. This method is noninvasive; however, it only provides a measurement of systolic and diastolic pressure on an intermittent basis; it does not provide the entire waveform on a continuous basis. Furthermore, use of this method often yields inaccurate results.
The tonometric method of measuring blood pressure is noninvasive and thus an improvement over invasive techniques and in addition, it is also more accurate than the auscultatory method discussed above. Furthermore, it has the capability of providing the entire blood pressure waveform, as opposed to only the systolic and diastolic pressures provided by the auscultatory method discussed above.
In a prior type of arterial tonometer, an array of individual transducer elements is placed directly on the tissue overlying an artery or blood vessel from which blood pressure is to be determined. The elements directly sense the mechanical forces in the tissue with which each of them is in contact. The elements of the array are dimensioned and spaced apart from each other such that a plurality of these elements is required to cover the entire diameter or width of the underlying blood vessel; i.e., the size of each element is designed to cover only a small fraction of the diameter of the underlying blood vessel. The pressure of the array against the tissue is increased to properly applanate the underlying vessel but without causing occlusion. The fluid pressure within the artery is then conducted through the vessel wall and the overlying tissue to the transducers.
It has been found that with the conventional tonometer, a continuous contour of the tissue stresses under the array is not obtained due to the use of discrete elements. Additionally, it is believed that in prior methods, no compensation means is provided for motion artifacts which may affect the forces translated to the sensors from the artery.
Thus, it would be desirable to provide a tonometer system and method for monitoring the pressure in a vessel, such as an artery, which is noninvasive and is capable of faithfully transducing the vessel pressure waveform.
It would also be desirable to provide a tonometer system and method which can compensate for artifacts which may tend to decrease the accuracy of the tonometer in monitoring the waveform.
It would also be desirable to provide a tonometer system and method which has improved reliability and repeatability of pressure waveform measurements.
The present invention addresses these needs.
SUMMARY OF THE INVENTION
Briefly, and in general terms, the invention provides a noninvasive tonometer system and method for monitoring the pressure waveform in a superficial peripheral vessel such as the radial artery. The apparatus comprises a planar rigid surface in which is placed at least one thin sensing diaphragm of a narrow rectangular geometry mounted in a housing to be placed on the tissue overlying the vessel of interest. The diaphragm is longer than the diameter of the vessel for purposely monitoring pressure in the tissue adjacent the vessel of interest. The tonometer also comprises deformation sensor means for measuring deformation of the diaphragm both over the vessel and adjacent the vessel, and signal processing means for combining the waveform of the vessel as monitored by the part of the diaphragm over the vessel with the waveforms of adjacent tissue to accurately determine the actual pressure waveform in the vessel.
In a preferred embodiment, the diaphragm is formed of stainless steel and is typically of a length which is 3 to 8 times as long as the undeformed diameter of the vessel and is oriented over the vessel such that its long dimension lies perpendicular to the longitudinal axis of the vessel. The diaphragm is constructed to be thick enough to applanate the underlying vessel yet be thin enough to be deformed by stresses in the tissue with which it is in contact. The deformation of the diaphragm is small enough to prevent distortion of the tissue surface contact stress profile. Therefore, deformation of the diaphragm over its length is proportional to the stresses of the tissue with which it is in contact. The deformation of the diaphragm may be detected by optical sensing means and in one embodiment, an array of light sources and receivers is employed. Because the beams of the light sources and receivers overlap, and because the diaphragm is a single piece, a continuous, smooth curve representing the pressure waveform is provided.
The back side of the diaphragm which is not in contact with the tissue serves as a common reflector to light sources positioned in the housing. Optical fibers carry light (typically visible, infra-red or ultra-violet light) from a light source and illuminate the reflector with that light. The diaphragm reflects the light in accordance with its deformation. Other optical fibers receive the reflected light, conduct it to light transducers such as photodetectors for measurement of the amount of light received. Bundles of illuminator and receiver optical fibers are preferably arranged in rows facing the diaphragm. Based on the position of the receive optical fibers and the amount of light received, a processor provides a pressure waveform. Measurements of the deformation of the diaphragm are converted to optical signals and then to electrical signals and represent the stress in the tissue contacted. These deformation measurements are a faithful analog of the pressure waveform of the vessel.
In typical operation, the diaphragm is placed on the tissue over the radial, ulnar, superficial temporal or similar surface arteries overlaying relatively rigid structures (bone, cartilage). The diaphragm is arranged so that its approximate center is positioned over the vessel. This is accomplished by determination of which region of the diaphragm is undergoing the maximal dynamic deformation with pulsatile intraluminal pressure variations. Because the diaphragm is longer than the diameter of the vessel, the diaphragm measures the stresses in tissue areas located peripherally to the vessel. Regions of the diaphragm which cover tissue peripheral to the vessel respond to stresses in that tissue which may be caused by artifacts. These signals may be used to remove the effects of motion artifacts on the stress measurement signal of the vessel of interest. Determination of a corrected stress measurement in which the effects of small variations in applanation have been reduced is accomplished by the subtraction of a fraction of the mean lateral stresses from the stress measurements immediately over the vessel. The fraction of the lateral stress to be subtracted is continuously adjusted to minimize the noise contained in the resulting vessel signal.
The intensity of the electromagnetic energy source should ideally remain constant during measurements as well as between calibrations. In practice, however, this is difficult to achieve. Temperature changes, aging and other factors may cause variations in light intensity. A means is employed to automatically adjust the energy source intensity to lessen the possibility of measurement errors. The energy source intensity is measured directly via a path which does not involve reflection from the diaphragm. The measured output is compared to a desired level, and the difference obtained is used to automatically adjust the intensity of the source until the difference is zero. This feedback regulation ensures a stability of the energy source.
In one embodiment, additional, similarly shaped diaphragms are positioned along the vessel at sites proximal and distal to the first diaphragm. The anatomy of most vessels changes along their length and there may be a preferred position along the vessel for monitoring. The plurality of diaphragms facilitates rapid determination and maintenance of measurements from this preferred location.
Other aspects and advantages of the invention will become apparent from the following detailed description and the accompanying drawings illustrating the features of the invention by way of example.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is an illustration of a tonometer in accordance with the invention enclosed in a housing and having a continuous diaphragm;
FIG. 2 is a schematic view of a tonometer in accordance with the principles of the invention;
FIG. 3 is a schematic diagram of an example of an arrangement of bundles of fiber optic cables for use with a continuous diaphragm;
FIG. 4 is a partial view of the overlapping of the beams of optical fibers which illuminate the continuous diaphragm;
FIG. 5 is a schematic diagram of an example of a circuit usable to control the output of an incandescent light source.
FIG. 6 is a schematic view of the function of the diaphragm in regard to tissue both over and peripheral to the vessel of interest;
FIG. 7 is a schematic block diagram of a processing circuit usable with the diaphragm and diaphragm deformation sensors;
FIG. 8 is a perspective view of an alternative embodiment of the pressure sensor having two diaphragms; and
FIG. 9 is a view of an embodiment having a movable mirror for scanning the light across the reflector.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
As is shown in the drawings, which are presented for the purpose of illustration only, the invention is embodied in a tonometer for noninvasively monitoring the pressure waveform in an underlying vessel of interest. Referring to FIGS. 1 and 2, the tonometer is in the form of a hand held probe 10 which preferably contains at least one generally rectangular diaphragm 12 which is to be placed over the tissue 24 overlying a vessel 14 such as an artery, and also contains means for detecting deformation of the diaphragm 12. As shown in FIG. 2, vessel 14 is disposed over an underlying, rigid bony structure 15. In one currently preferred embodiment, the diaphragm 12 is reflective, and there exists a light source 16 for providing light and a plurality of optical fibers 18 for transmitting such provided light to the reflective diaphragm 12. The tonometer also includes a plurality of groups of receiver optical fibers 17 for receiving light reflected from the reflective diaphragm 12, and light transducers, such as photo-transistors 22 for measuring the amount of light received from the diaphragm 12 and generating an electrical signal in response. The signal produced is provided to a processor 21 which in turn provides a waveform to a display 23.
Variations in the amount of light received by each group receiver optical fibers 19 are proportional to the contact tissue stresses both over and lateral to the vessel 14. These stresses correlate with systolic, diastolic and mean pressures and provide guidance for positioning of the hand held probe 10.
In applying the tonometer 10 to the tissue 24 overlying the vessel 14, enough force is used to depress and flatten the vessel 14 as shown in FIG. 2. A limited amount of vessel flattening eliminates the normal curvature of the vessel and permits translation of the fluid pressure of the vessel to the diaphragm 12. Thus, the vessel wall 14 in this region is forced to lie generally parallel to the surface of the tissue 24. The wall bending stress of the vessel is essentially eliminated so that stress sensed at the tissue surface is substantially proportional to pressure within the artery.
A tonometer made in accordance with the principles of the invention measures the stresses in the tissue overlying the vessel 14 of interest. As shown in FIG. 1, the tonometer 10 comprises a housing 26 having a surface 28 of which a portion is adapted for deformation of the tissue 24 and applanation of the vessel 14; at least one diaphragm member 12 mounted in the housing 26, adapted to be placed in contact with tissue 24 adjacent the vessel 14 and capable of being displaced in a continuous manner in response to tissue stresses adjacent the vessel 14.
The diaphragm 12 in this embodiment comprises a thin, continuous plate having a dimension which is from about 3 to about 8 times longer than the diameter of the typical vessel of interest. The diaphragm 12 is currently made of stainless steel, although it may be formed from other metals, such as aluminum, or copper, and from suitable deformable reflective plastic films or laminates or other materials. In this embodiment, the surface of the diaphragm 12 facing the optical fibers is coated to be highly reflective and thus provides a reflecting target surface for each emitter fiber 13. The optical emitter fibers 18 and the group receiver fiber 19 may be located in bundles (or groups) 19 as shown in FIG. 3. Referring to FIG. 3, bundles 19 of optical fibers are shown.
The center fiber 13 is for illumination of a portion of the diaphragm-12 while the surrounding fibers 20 are for receiving light reflected by the diaphragm 12. In another embodiment, the fiber may not be disposed in the concentric manner of FIG. 3 but may be disposed in a random manner.
Referring now to FIGS. 4, the illuminator fibers 13 provide overlapping illumination of the diaphragm 12. The light source 16 provides light to the emitter fibers 13 which transmit the illumination to the reflective diaphragm 12, which in turn reflects this illumination. The reflected illumination is received and carried through the receiver optical fibers 20 to a photodetector 22 (FIG. 2) providing a signal proportional to the light received from the reflecting diaphragm 12. The beams of the receiver fibers 20 are also overlapping. Fibers having high numerical apertures may be used to achieve this result. The signal is then received by signal processing means 21. The feature of overlapping the bundles of fibers permits increased signal to noise levels as well as a continuous, smooth curve representative of the pressure waveform.
Laser light, high wattage lamps and light emitting diodes may be used as alternate sources of electromagnetic radiation, although an incandescent lamp is the currently preferred light source. An incandescent lamp, although self-regulating, requires approximately 40-50 minutes to stabilize instability in the light source can result in inaccuracies in waveform readings unless a means is applied to compensate for such instabilities. Referring to FIG. 2, one means to provide control over the lamp 16 output is to use an additional optical fiber 30 to conduct the light output of the lamp directly to a detector 32 and to provide the detected signal to a lamp control 34. A feedback control circuit illustrated in FIG. 5 was implemented to regulate the lamp intensity by controlling its current. Because the lamp output is a nonlinear function, current stability is critical. To prevent oscillations, an RC-filter is provided in the error amplifier feedback circuit. This effectively maintains the lamp intensity constant with no error over a long period of time. In the embodiment shown in FIG. 5, the resistors R1 and R2 were 10 K ohms, resistor R3 was 20 K ohms, device D1 was an MRD36N, device D2 was a CA3140T, transistors T1 and T2 were 2N2222, transistor T3 was a 40409, lamp L1 was rated at 5 volt, 115 ma, capacitor C1 was 10 μF and C2 was 1000 μF.
Motion occurring during the pressure waveform monitoring process can produce artifacts by affecting the stresses in the tissue on which the tonometer is pressing and therefore can render pressure measurements unusable. Such motion may occur due to small variations in the displacement of the tonometer head with respect to the vessel resulting from patient or operator movement. In accordance with the principles of the invention, motion artifacts may be reduced or eliminated. Referring now to FIG. 6, a center region 36 of the diaphragm 12 can be placed generally directly over the vessel 14 of interest while the end regions 38 of the diaphragm are placed over tissue adjacent or peripheral to the vessel 14. While the central region 36 experiences vessel pressure stresses and stresses caused by motion artifacts, the end regions of the diaphragm 12 experience almost exclusively only stresses caused by motion artifacts. Although received in each region, the stresses caused by motion artifacts are not the same in each region. Therefore, motion artifact signals detected in the end regions 38 of the diaphragm 12 may be combined with the signals from the central region 36 to provide a more accurate waveform and substantially reduce the effects of patient motion. A circuit usable for such correction is shown in FIG. 7.
Because the tonometer in accordance with the invention can measure tissue contact stresses in regions both immediately over the vessel and remote from the vessel, a signal can be provided which is a combination of the pressure waveform plus the displacement noise [referred to as S(t)] and signals can be provided which represent the displacement noise alone, referred to as IN(t)]. Ideally it would be possible to simply subtract the time varying (high pass filtered) component of the noise signal [N f (t)] from the pressure signal S(t) to correct for the undesired displacement variation. Thus the corrected signal would be simply:
P.sub.correct (t)=S(t)-N.sub.f (t)
In practice, the amplitude of the displacement noise generated in the tissue just over the blood vessel is different from the amplitude produced in the tissue remote from the vessel. If the relationship remained constant, then the corrected pressure could be found by:
P.sub.corrected (t)=S(t)-A N.sub.f (t)
where A=a constant multiplying factor
If the relationship between central and lateral motion induced noise was constant for all individuals, then a fixed coefficient "A" could be used as in the equation above. Unfortunately, the artifact pressure created in one region relative to that in another does not remain constant over time even for a given individual. Referring again to FIG. 6, the tissue is represented as a series of springs as in a mattress, the amount of force created by each spring is given simply by its displacement X times its spring constant K. In real tissue the constants for each "spring" vary with time due to factors which may include viscoelastic flow, changes in perfusion, temperature and others. Because of the variability in the relationship between the noise contained in remote regions [N(t)] and the noise component of the signal just over the vessel, it is not as accurate to simply set a single ratio factor such as "A" above to provide compensation. Thus a method to dynamically select the coefficient to be applied to N f (t) is used.
Referring now to FIG. 7, the signal from directly over the vessel 14 is indicated by S(t) and the signals from the regions remote from the region directly over the vessel are indicated by N f (t). The constant "A" is replaced by a parameter "a" which multiplies the high pass filtered 40 noise signal. The value of "a" is determined in one embodiment by the following. Firstly, the products of the scaling factor and the time varying component of the noise channel are formed:
(a+dA) * N.sub.f (t) and (a-dA) * N.sub.f (t)
where dA is a selected as a constant typically less than 5% of the range of A which is 0 to 1, thus a typical dA might be 0.05. Choice of a smaller dA will result in more time being required to settle or adjust to the best value for "a" while larger values may result in less effective noise cancellation. As used herein, the symbol * indicates multiplication.
Secondly, the differences between these scaled noise signals and the time varying (mean value removed by high pass filter) component of the pulse signal S f (t) are formed such as by difference amplifiers 44:
difference signals=S.sub.f (t)-(a±dA) * N.sub.f (t)
Thirdly, the difference signals are squared to produce two signals proportional only to the amplitude of the differences:
squared differences=difference signals.sup.2
Fourthly, the squared difference signals 46 are low pass filtered 48 using a filter whose time response spans many heartbeats.
To illustrate the operation of the system, in one case when the noise signal is zero, the filter outputs are Just the high-pass filtered pulse signal (time varying part) squared and low pass filtered, the squaring operation forces the pulse signal to be uni-directional, i.e. always positive going with respect to zero. The low pass filter's effect on this signal is to find the mean value of the squared pulse signal. Thus under these conditions, the output of the two LPF1 and LPF2 are just the mean of the squared pulse signals and are the same in both inputs of the comparator 50. Under these conditions, the comparator output would switch up and down by one or two counts remaining relatively stable.
In the case when the noise signal has some finite value in both the pulse signal and noise signal channels, the differing multipliers (a+dA and a-dA) cause a larger or smaller portion of the noise energy to be added to the pulse signal. This results in one of the LPF's producing a larger average value than the other.
Fifthly, the comparator 50 causes the value of "a" to increase or decrease by means of the up/down counter 52 and the digital-to-analog converter 54 toward the value which is producing the lowest LPF output (i.e. smallest noise). As this process continues, eventually the best value of "a" is found (that is, the value producing the least mean squared error), then the direction of change of "a" is reversed because now further change of "a" in the same direction would have moved toward an increasing error. The automatic reversal occurs due to the opposite LPF producing the largest average noise level.
Sixthly, to produce a noise reduced output waveform, the original noise contaminated pulse signal from comparator 50 is combined with the best choice of "a" ±dA times the filtered noise channel signal automatically selected by one of the two switches 56 in difference amplifier 58 to result in:
P.sub.out (t)=S(t)-(a±dA)N.sub.f (t)
In this embodiment, the automatic selection of a+dA or a-dA is accomplished by use of the comparator 50 output as a control on the switches i and 2. If the comparator output is true, this indicates that LPF1 has the highest noise energy. This also means that LPF2 had the least noise (corresponding to a coefficient of a-dA) in its output. The true state of the comparator will cause the noise signal multiplied by the (a-dA) term to be added to the incoming vessel signal S(t) to obtain the most noise free output.
The fraction of the lateral stress to be subtracted is determined by continuously adjusting the fraction to minimize the noise contained in the resulting vessel signal. The optimum coefficient to use is determined by testing the performance of two slightly different coefficients in reducing the mean squared noise content of the vessel signal, then increasing or decreasing the coefficient as needed to produce the lowest mean squared noise content. The fraction of the lateral stress to be subtracted is determined by continuously adjusting the fraction to minimize the noise contained in the resulting vessel signal.
One advantage of the pressure waveform monitor in accordance with the principles of the invention is that measurement of the continuous stress contour across the tissue in the region of the vessel 14 (FIG. 2) is possible. The hand held probe 10 (FIG. 1) is positioned by the user so that the long axis of the rectangular diaphragm 12 (FIG. 2) is oriented substantially perpendicular to the axis of the vessel 14 against the tissue over the vessel and on either side of the vessel. The measurement of the continuous stress contour is preferably viewable simultaneously on a display screen 32 (FIG. 1) in an interactive mode. A specific region of the diaphragm may then be chosen to monitor blood pressure.
In one embodiment, the stainless steel diaphragm size chosen was 0.81 mm wide and 0.005 mm thick. With these dimensions and fiber-optic sensitivity data, it is predicted that the pressure sensitivity should be 3.5 mV/mmHg. All channels of the fiber deformation sensors may be recorded, input to a sample and hold analog-to-digital convertor and digitized for computer analysis.
Thus the pressure waveform monitor in accordance with the invention provides a continuous curve of the pressure waveform by using a continuous diaphragm over the vessel of interest and peripheral tissue. The monitor permits the averaging of signals by overlapping beams of the sensors to attain the continuous curve. The monitor can present not only diastolic and systolic pressures, but also the entire waveform. Means may be included in the processor to store data digitally for comparison purposes or for other manipulation.
Referring now to FIG. S, an embodiment having two sets of optical fiber bundles 60, 62 is shown. A single diaphragm 14 covers both sets. The optical fiber bundles 60, 62 are located in separate grooves 64, 66 respectively and are formed in the tonometer head 68. The use of multiple diaphragms will permit placing the tonometer head over the vessel of interest and obtaining multiple pressure waveforms along the vessel, one of which may be better than the others. It is known that the anatomy of a vessel varies along its length, such variations include thickness of overlying tissue, location and stiffness of bone, ligament, muscle and tendon under and beside the vessel and dimension of the vessel. Therefore, there may be better positions along the vessel at Which to monitor pressure waveforms.
Another embodiment is shown in FIG. 9 where a movable mirror 70 is used to reflect a beam from a transmitter 72 to the diaphragm 12. The diaphragm reflects the beam to a receiver 74 Which determines the intensity and position of the reflected light.
In another embodiment, the light sources and detectors can be placed immediately adjacent the diaphragm using an LED array along one row adjacent the reflective diaphragm, and a series of photodetectors in another row next to the light emitting array, to receive light reflected from the diaphragm. This approach eliminates the need for optical fibers.
While several particular forms of the invention have been illustrated and described, it will be apparent that various modifications can be made without departing from the scope of the invention. Accordingly, it is not intended that the invention be limited, except as by the appended claims.
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A pressure waveform monitor noninvasively monitors the pressure waveform in an underlying vessel such as an artery. The apparatus comprises at least one continuous, relatively thin and narrow diaphragm mounted in a housing to be placed on the tissue overlying the vessel of interest. The diaphragm is longer than the diameter of the vessel for purposely monitoring pressure in the tissue adjacent the vessel of interest. The tonometer also comprises deformation sensor means for measuring deformation of the diaphragm both over the vessel and adjacent the vessel, and signal processing means for combining the waveform of the vessel as monitored by the part of the diaphragm over the vessel with the waveforms of adjacent tissue to accurately determine the actual pressure waveform in the vessel.
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[0001] The invention concerns a valve control device in accordance with the preamble of patent claim 1. Such a valve control device is, for example, an electronic control unit for an antilock braking system (ABS) in a motor vehicle, where the brake liquid operating the wheel brakes is controlled by means of two valves per wheel. The valves are operated by an electric magnet.
[0002] The invention also concerns a process for the manufacture of such a valve control device.
BACKGROUND OF THE INVENTION
[0003] A known ABS system such as described in EP 0499 670 A1, features a housing with a housing frame and a cover. In the housing frame, valve spools are embedded in a yielding fashion. This is effected by positioning the valve spools in their location relative to the housing frame and filling in the spaces with a compound. The component parts of the valve spool such as a wrapped spool body and its surrounding yoke ring are filled in with a compound before being fitted into the housing frame. Then the valve spools are fitted into the housing and fixed into their position by embedding.
[0004] The disadvantage here, however, is that several embedding processes are necessary. The compound is not used as a component part of the housing but only for the yielding embedding of the spools. This yielding embedding, in turn, is only used to compensate tolerances if the valve unit is later fitted onto the valve control device. Further housing components are necessary in order to be able to provide a watertight encapsulation of the entire valve control device.
[0005] In DE 42 32 205 A1, in a housing frame of the valve control device, the components of a valve spool such as the wrapped spool body, yoke ring, and the valve spool itself will be embedded in yielding fashion by injection moulding with a compound in a single process and then fitted as the housing bottom to a circuit carrier. On the other side, an additional cover is fitted over the circuit carrier so that the valve control device is provided with watertight encapsulation.
[0006] The disadvantage with this valve control device is that the embedded arrangement—due to the unprotected circuit carrier—also requires an additional housing as the soft compound alone does not provide a reliable protection against environmental influences. The separate housing, in its turn, requires sealing lips and ventilation diaphragms that protect the circuit carrier against humidity.
[0007] The object of the invention is to provide a valve control device that is watertight, features few housing parts and can be manufactured and fitted easily and at low cost.
SUMMARY OF THE INVENTION
[0008] According to the invention, the object is achieved by a valve control device with the characterising features of patent claim 1 and a process in accordance with patent claim 8. The valve control device according to the invention is completely embedded in compound. The circuit carrier and the valve spools are positively covered by a compound. The positive cover consisting of compound provides the housing of the valve control device, which on the one hand fixes the electronic and mechanical components in position, that is, it holds them in the required position and on the other hand encapsulates them in order to protect them against environmental influences, in particular, humidity. In the process for the manufacture of such a valve control device, the circuit carrier is connected to the electronic components and the spools are mechanically connected to each other; then the spools are fixed in position on the embedding tool, embedded, and finally hardened. Here, it is also possible to use different materials with different properties as a compound. After processing the compound can be hard and rigid or soft and elastic. However, it may also feature different properties in different places such as e.g. soft and elastic in the area of the spools and hard and rigid in the external area and in the area of the printed circuit board.
[0009] The advantages of the invention are that only one embedding process is still needed but no assembly process where several parts have to be put together in order to provide the valve control device with a watertight housing. This also does away with the need for testing, in particular with regard to housing leakage. Individual separate housing parts are no longer required. At the same time, there is no longer any need for flexible seals, sealing lips, and ventilation diaphragms.
[0010] Advantageous further embodiments of the invention result from the sub-claims. Here, yoke components or a metal plate, which also serves as a yoke component and/or is used for heat dissipation for the power components, can be addionally embedded into the compound. Also, in contrast to standard opinion, it is not a soft compound that is used but a compound which is hard and rigid after hardening. The spools will then be arranged immovably in the compound. Tolerance compensation will then no longer be effected via the movable arrangement of the spools in the compound but via the internal diameter of the spool. Also, in other advantageous embodiments, the yoke is designed as a C-shaped, bell-shaped, or U-shaped yoke and post-arranged on the spools after embedding. Furthermore, the mechanical connection between spool and circuit carrier can also represent the electrical connection.
BRIEF DESCRIPTION OF THE DRAWINGS
[0011] In the following, the invention is to be explained in more detail by means of embodiment examples and the figures. The figures below show:
[0012] [0012]FIG. 1: Valve control device without metal plate
[0013] [0013]FIG. 2: Spool arrangement
[0014] [0014]FIG. 3 a : Side view, spool body
[0015] [0015]FIG. 3 b : Front view, spool body
[0016] [0016]FIG. 4 a : Side view, yoke
[0017] [0017]FIG. 4 b : Front view, yoke
[0018] [0018]FIG. 5: Valve control device with metal plate
[0019] [0019]FIG. 6: Spool arrangement
[0020] [0020]FIG. 7 a : Side view, spool body
[0021] [0021]FIG. 7 b : Front view, spool body
[0022] [0022]FIG. 8 a : Side view, bell-shaped yoke
[0023] [0023]FIG. 8 b : Front view, bell-shaped yoke
[0024] [0024]FIG. 9 a : Side view, U-shaped yoke
[0025] [0025]FIG. 9 b : Front view, U-shaped yoke
[0026] [0026]FIG. 10 a : Yoke plate, seen from below
[0027] [0027]FIG. 10 b : Cross-section of the yoke plate
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0028] [0028]FIG. 1 shows an embedded valve control device without metal plate with the outline of a valve unit 12 . In the compound 8 , there is the circuit carrier 1 , in particular a printed circuit board populated with the electronic components 2 . The electronic components 2 may either be encapsulated in a housing or be mounted on the printed circuit board 1 as a blank chip which can also be protected by the compound 8 . At the same time spools 5 are mounted on the circuit carrier 1 via the compound. The protective cover consisting of compound features different thicknesses and solidity in different places. The spacing between two spools 5 is completely filled in with compound 8 . The remaining spool area that is the top side of the spool, its bottom and external side are only covered by a thin coating of compound 8 . The circuit carrier 1 is covered by a somewhat thicker compound layer 8 . In this figure, boundary layers between the individual embedded components are indicated. This is to suggest that the compound 8 may also consist of different materials whichmay again feature different properties. Within the spool area the compound 8 can be soft and elastic, and in the circuit carrier area it may be hard and rigid. In the area between the spools 5 and the circuit carrier 1 the compound 8 may only have low elastic properties. In order to simplify the further description of the application examples, it is assumed that the compound is homogeneous and features in all places the same properties, does not have any boundary areas, and becomes hard and rigid after processing. The spools surrounded by the compound, also designated as valve spools, consist of spool body 3 and windings 4 and represent the electric magnets by means of which the valves of valve unit 12 are operated via the valve domes 11 . The electric spool connections 7 , mounted on the side of the spool body 3 , protrude into the printed circuit board 1 . In this figure, two spools are shown that are facing each other so that their side-mounted spool connections 7 are located next to one another. This setup is particularly space-saving. The spools and the circuit carrier 1 are completely embedded, excluding the inside of the spool. In the inside of the spool, the spool body 3 is visible. The external surfaces of the spool body 3 and the spool windings 4 are positively covered by the compound 8 . This embedded arrangement protects all components, in particular the electronic components 2 , against unfavorable environmental conditions such as e.g. water, humidity, and dust. In this case, the compound 8 consists of epoxy resin. The compound 8 will become rigid when the arrangement has hardened. The embedded components such as spools 5 , circuit carrier 1 , electronic components 2 are fixed in position by the compound. With this setup, there is no longer any need for a housing. The compound 8 itself provides the housing. In the area between the spools 5 and the circuit carrier 1 , recesses are provided into which the yoke 6 can be fitted after embedding. In comparison to the electronic components 2 , yoke 6 is insensitive against any environmental influences and therefore is not embedded in this application example but subsequently fitted to the embedded arrangement. The yoke 6 , which is pushed sideways over the spool, is designed as a C-shaped yoke and features a bead 10 on its top and bottom sides. Here, within the spool body 3 , the beads 10 of the yoke 6 are positioned centrally above the cavity, into which the valve dome 11 is later introduced. Furthermore, in addition to the valve control device, this figure also shows the hydraulic assembly 12 , in particular the valve unit, whose valve domes 11 protrude into the spool body 3 .
[0029] In order to produce such an embedded valve control device, it makes sense to set up the embedding tool such that it also forms domes that are introduced into the spool body and on which the spools are fixed during the embedding process. Before embedding the spool bodies 3 have been connected with the circuit carrier 1 . Here, the connection pins 7 of the spool bodies 3 do not only provide the electrical but also the mechanical connection, by means of which the circuit carrier 1 is at least partially positioned within the embedding tool.
[0030] [0030]FIG. 2 shows the spool arrangement with the circuit carrier before embedding. The two spools 5 shown here each consist of a spool body 3 , on which the spool windings 4 are mounted. The connections 7 of the spools 5 have not been fitted symmetrically with regard to the spool axis but mounted on one side. The spool connections 7 are inserted through the boreholes of the circuit carrier 1 , in particular the printed circuit board, and are then fixed in position by means of pressing forces or soldering. They form a fixed unit and can be embedded together. Furthermore, there is a free space between the spools 5 and the printed circuit board 1 . The side-mounted connections and the free space are used to create mounting space for the yoke which is not shown in this figure and which is pushed sideways over the spools after embedding.
[0031] The FIGS. 3 a and 3 b show the spool body. In FIG. 3 a as a side view, and in FIG. 3 b as a front view. Here, the connections 7 are fed out to one side of the spool body 3 . The connections 7 do not only have the task to provide an electrical contact between the circuit carrier and the spool but also support the printed circuit board—as shown in FIG. 2—during the embedding process. For this reason the connections 7 must be dimensioned such that they are sufficiently stable to be able to withstand the press-fitting or soldering processes, and to support the circuit carrier. Moreover, they must be arranged such that they do not obstruct the yoke. The diameter of the cavity in the inside of the spool body must be selected to be sufficiently large so that the permissible tolerances, coming from the arrangement of the valve domes in the valve unit, can be compensated for. This takes account of the fact that the embedded spool bodies with windings will later be arranged in a fixed and immovable position in the compound. The spool body consists of synthetic material.
[0032] The FIGS. 4 a and 4 b show the yoke in different perspectives. In FIG. 4 a as a side view, and in FIG. 4 b as a front view. As can be seen from the figures, the yoke 6 is designed as a C-shaped yoke and features a bead 10 on its top and bottom sides, into which the valve dome is later inserted. The yoke 6 is pushed over the spool body as shown in FIGS. 3 a and 3 b . As the yoke 6 which consists of sheet metal can only be mounted after embedding, this may also be located movably so that the interior diameter of the beads 10 does not need to compensate for all tolerances coming from the arrangement of the valve domes in the valve unit. Tolerance compensation is effected by means of the movability of yoke 3 .
[0033] [0033]FIG. 5 shows an embedded valve control device with metal plate 13 and with the outline of a valve unit 12 . In the compound 8 , there is the circuit carrier 1 , in particular a printed circuit board populated with the electronic components 2 . The electronic components 2 may either be encapsulated in a housing or be mounted on the circuit carrier 1 as a blank chip. At the same time spools are mounted on the circuit carrier 1 , which feature a spool body 3 and windings 4 . Between the circuit carrier 1 and the spools, a metal plate 13 is located. The metal plate 13 features insets 14 on to which the spool body 3 is pushed. The metal plate 13 , in this embodiment, has two functions. Mainly, it is used as a component part of the yoke, and, on the other hand, it also serves as a metal body to dissipate the heat from the power components mounted on the circuit carrier 1 . The spool bodies 3 and the windings 4 , connected with the metal plate 13 —hereinafter also designated as yoke plate 13 —and the circuit carrier 1 represent the electric magnets by means of which the valves of valve unit 12 are operated via the valve domes 11 . The electric spool connections 7 , mounted on the side of the spool body 3 , protrude into the printed circuit board 1 . In this figure, two spools are shown that are facing each other so that their side-mounted spool connections 7 are located next to one another. This setup is particularly space-saving. The spools and the circuit carrier 1 are completely embedded, excluding the inside of the spool. In the inside of the spool, the interior spool body 3 is visible. The external surfaces of the spool body 3 and the spool windings 4 are positively covered by the compound 8 . This embedded arrangement protects all components, in particular the electronic components 2 , against unfavorable environmental conditions such as e.g. water, humidity, and dust. In this case, the compound 8 consists of epoxy resin. The compound 8 will become rigid when the arrangement has hardened. The embedded components such as spools, circuit carrier 1 , yoke plate 13 , and electronic components 2 are fixed in position by the compound. With this setup, there is no longer any need for a housing. The compound 8 itself provides the housing. In the area between the individual spools, recesses are provided into which the yoke bell 15 can be fitted after embedding. In comparison to the electronic components 2 , yoke bell 15 is insensitive against any environmental influences and therefore is not embedded in this application example but subsequently fitted to the embedded arrangement. The yoke bell 15 , which is pushed either from above or below over the spool, is designed as a bell-shaped yoke and features a bead 10 to one side. On the opposite side, this bead is shown by the inset 14 of the yoke plate 13 . Here, within the spool body 3 , the bead 10 and the inset 14 of the yoke plate 13 are positioned centrally on the cavity, into which the valve dome 11 is later introduced. Instead of the yoke bell 15 , which completely encapsulates the spool winding 4 , it is also possible to use a U-shaped yoke that does not cover the embedded spool winding on two sides. Furthermore, in addition to the valve control device, this figure also shows the hydraulic assembly 12 , in particular the valve unit, whose valve domes 11 protrude into the spool body 5 .
[0034] In order to produce such an embedded valve control device, it makes sense to set up the embedding tool such that it also forms domes that are introduced into the valve body and on which the spools are fixed during the embedding process. Before embedding the spool bodies 5 have been connected with the circuit carrier 1 and the metal plate 13 . Here, the connection pins 7 of the spool bodies 3 do not only provide the electrical but also the mechanical connection, by means of which the circuit carrier 1 is at least partially positioned within the embedding tool. The positive connection between the valve body 3 and the inset 14 of the metal plate 13 also provides a mechanical fixing during the embedding process.
[0035] [0035]FIG. 6 shows the spool arrangement with the circuit carrier and the yoke plate before embedding. The two spools 5 shown here each consist of a spool body 3 , on which the spool windings 4 are mounted. The connections 7 of the spools 5 have not been fitted symmetrically with regard to the spool axis but mounted on one side. The spool connections 7 are inserted through apertures 17 of the yoke plate 13 into the boreholes of the circuit carrier 1 , in particular the printed circuit board, and are then fixed in position by means of pressing forces or soldering. The yoke plate 13 is fixed in position by positively introducing the insets 14 of the yoke plate 13 into the spool body 3 . Spool body 3 , circuit carrier 1 , and metal plate 13 form a fixed unit and can be embedded together. Furthermore, there is a free space between the individual spools. The free space is used to create mounting space for the yoke bell which is not shown in this figure and which is pushed either from above or below over the spools after embedding.
[0036] The FIGS. 7 a and 7 b show the spool body. In FIG. 7 a as a side view, and in FIG. 7 b as a front view. Here, the connections 7 are fed out to one side of the spool body 3 . The connections 7 do not only have the task to provide an electrical contact between the circuit carrier and the spool but also support the printed circuit board—as shown in FIG. 6—during the embedding process. For this reason the connections 7 must be dimensioned such that they are sufficiently stable to be able to withstand the press-fitting or soldering processes, and to support the circuit carrier. Moreover, they must be arranged such that they do not obstruct the yoke bell. The cavity on the inside of the spool body features different diameters. The smaller diameter on the one side of the cavity in the inside of the spool body must be selected to be sufficiently large so that the permissible tolerances, coming from the arrangement of the valve domes in the valve unit, can be compensated for. This takes account of the fact that the embedded spool bodies with windings will later be arranged in a fixed and immovable position in the compound. The larger diameter on the other side, together with the sheet thickness of the yoke plate insets, must again yield the smaller diameter. The spool body consists of synthetic material.
[0037] The FIGS. 8 a and 8 b show the yoke bell in different perspectives. In FIG. 8 a as a side view, and in FIG. 8 b as a front view. As can be seen from the figures, the yoke bell 15 is designed as a pot-shaped yoke and features a bead 10 on one side, into which the valve dome is later inserted. The yoke bell 15 is pushed over the spool body as shown in FIGS. 7 a and 7 b . As the yoke bell 15 which consists of sheet metal can only be mounted after embedding, this may also be located movably so that the interior diameter of the bead 10 does not need to compensate for all tolerances coming from the arrangement of the valve domes in the valve unit. Tolerance compensation is effected by means of the movability of yoke bell 3 .
[0038] Instead of a yoke bell, the FIGS. 9 a and 9 b show a U-shaped yoke 16 in different perspectives. In FIG. 9 a as a side view, and in FIG. 9 b as a front view. As shown in the figures, yoke 16 is U-shaped that is, it does not completely encapsulate the spool in the same way as the bell-shaped yoke but is open on two sides. This setup also features a bead 10 on one side, into which the valve dome is later inserted. The U-shaped yoke 16 is pushed over the spool body as shown in FIGS. 7 a and 7 b . As the U-shaped yoke 16 which consists of sheet metal can only be mounted after embedding, this may also be located movably so that the interior diameter of the bead 10 does not need to compensate for all tolerances coming from the arrangement of the valve domes in the valve unit. Tolerance compensation is effected by means of the movability of the U-shaped yoke 16 .
[0039] [0039]FIG. 10 a shows the yoke plate 13 from below before assembly together with the other components and before embedding. The valve spools are pushed onto the circular insets 14 . Next to the insets 14 there are apertures 17 to provide for the later feeding of the spool connections through the yoke plate to the circuit carrier. In oder to illustrate more clearly the later setup, this figure also shows the plan view of the yoke bell 15 and the U-shaped yoke 16 , which, respectively, together with the yoke plate form the yoke for a spool.
[0040] [0040]FIG. 10 b shows the cross-section view through the yoke plate. The metal yoke plate 13 features insets 14 which protrude from the yoke plate level. They are later introduced into the inside of the spool. The apertures 17 in the yoke plate 13 provide for the later making of the spool connections, which represent the electrical and mechanical connection to the circuit carrier.
[0041] For the embodiments shown it would seem obvious that the positively applied compound does not need to be homogeneous but may consist of different materials, and that the different materials can also be fitted in stages.
[0042] In addition, the yoke components 6 , 15 , 16 , that, in the embodiments are not located underneath the compound, can also be embedded positively together with the other components, thus saving a further assembly process step.
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2.1. Existing valve control devices are set up in housings that feature a cover and a frame in which the valve spools are embedded. Between the cover and the frame, there is the circuit carrier with the electronic components. With the new valve control device, there is no longer to be any need for a housing, and the manufacturing process is to be simplified.
2.2. In order to save the housing, the valve control device is embedded together with the circuit carrier. The compound itself provides the housing of the valve control device. In the manufacturing process, following the mechanical and electrical connection of spools and circuit carrier, the spools are positioned in the embedding tool, and the complete arrangement is then embedded preferably with epoxy resin.
2.3. Due to their high reliability such valve control devices are suitable for antilock braking systems, anti-slip control systems, electronic brake servos, and electronic stabilizing programs in motor vehicles.
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BACKGROUND
[0001] 1. Field of Invention
[0002] The present invention relates to washing furniture in the bathroom, and more particularly to an adjustable water-spraying device mounted on a toilet seat unit.
[0003] 2. Description of Related Art
[0004] For the convenience and sanitary requirements of a user, washing equipment is added next to the side of a toilet seat unit to spray water to clean the user's anus. This is a so called hidro bidet shower.
[0005] Conventional hidro bidet showers are divided into two kinds, mechanical and electronic type. In the mechanical washing equipment, the water is sprayed to clean the user's anus by conducting water to an adjutage with a conduit.
[0006] However, the mechanical washing equipment only has a cold water spraying function and the water temperature or pressure cannot be modified. Moreover, the mechanical washing equipment cannot control the spraying position in accordance with different genders such that the requirements of different users cannot be satisfied.
[0007] In the electronic washing equipment, an electrical circuit replaces the control device. A heating unit is also added to heat the water. A touch-panel microcomputer controls both the electrical circuit and the heating unit. Although the electronic washing equipment can modify water temperature, the cost thereof is very expensive and the power consumption caused by the heating unit increases. In addition, the leakage also occurs making the electronic device more difficult to sell.
SUMMARY
[0008] It is therefore an object to provide an adjustable water-spraying device to enable water heating, the water pressure adjustment and the spraying position adjustment so that the requirements of different users can be satisfied.
[0009] It is therefore another object to provide an adjustable water-spraying device with a lower manufacturing cost and water temperature controllable function that also has low power consumption and no electrical leakage problem.
[0010] In accordance with the foregoing description and objectives, an adjustable water-spraying device is provided and includes different controlled valves in different spaces to respectively modify the water temperature and the flow direction. Thus, both male and female users can choose their own spraying position and desirable water temperature.
[0011] The water-spraying device is secured next to a toilet seat unit and includes a base, a first control valve, a second control valve and two water-spraying units.
[0012] The base includes a first space, a second space, a cold water hole, a hot water hole, a first outlet and a second outlet. The first space is communicated with the second space. The cold water hole and the hot water hole communicate with the first space, and the first outlet and the second outlet communicate with the second space. The first control valve is secured in the first space and includes a rotatable knob and a valve core connected with the rotatable knob to control the opening and the flow. The second control valve is secured in the second space to control the opening between the first outlet and the second outlet. The water-spraying units are respectively linked with the first outlet and the second outlet, and include a conduit and a spraying tube associated with the conduit and extended to the toilet seat unit. By controlling the first control valve and the second control valve to modify the water temperature and the flow direction, and one of the water-spraying units is driven to spray the mixed water to clean.
[0013] In accordance with another objective, an adjustable water-spraying device is provided and includes a base, at least one control valve and a water-spraying unit.
[0014] The base includes a cold water hole, a hot water hole and an outlet. The control valve includes a valve core secured on the base to control the opening and the flow between the cold water hole and the hot water hole. The water-spraying unit includes a conduit linked with the outlet and a spraying tube associated with the conduit and extended to the toilet seat unit to spray the mixed water to clean.
[0015] Therefore, the first step of the water-spraying device is to control the first control valve to modify the water temperature and the flow, and the second step is to control the second control valve to operate the desirable water-spraying unit to conform to the requirements of both male and female users.
BRIEF DESCRIPTION OF THE DRAWINGS
[0016] The accompanying drawings are included to provide a further understanding of the invention, and are incorporated in and constitute a part of this specification. The drawings illustrate embodiments of the invention and, together with the description, serve to explain the principles of the invention. In the drawings,
[0017] FIG. 1 is an operational, perspective view of the first embodiment of a water-spraying device of the present invention;
[0018] FIG. 2 is a sectional view of the water-spraying device in the FIG. 1 ;
[0019] FIG. 3 is a partial sectional view of a spraying tube of the water-spraying unit in FIG. 1 ;
[0020] FIG. 4 is an operational, sectional view of a toilet seat unit with the water-spraying device in FIG. 1 ;
[0021] FIG. 5 is a partial sectional view of a second control valve of the base in FIG. 1 ;
[0022] FIG. 6 is a sectional view of a second embodiment of the water-spraying device of the present invention;
[0023] FIG. 7 is a top view of a third embodiment of the water-spraying device of the present invention;
[0024] FIG. 8 is a sectional view of a fourth embodiment of the water-spraying device of the present invention; and
[0025] FIG. 9 is a sectional view along the cross-line 9 - 9 in FIG. 8 .
DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0026] Reference will now be made in detail to the present preferred embodiments of the invention, examples of which are illustrated in the accompanying drawings. Wherever possible, the same reference numbers are used in the drawings and the description to refer to the same or like parts.
[0027] While the specification concludes with claims defining the features of the invention that are regarded as novel, it is believed that the invention will be better understood from a consideration of the following description in conjunction with the figures, in which like reference numerals are carried forward.
[0028] Refer to FIG. 1 and FIG. 2 . FIG. 1 illustrates an operational, perspective view of the first embodiment of a water-spraying device. FIG. 2 illustrates a sectional view of the water-spraying device in the FIG. 1 .
[0029] The water-spraying device 100 is secured next to a toilet seat unit 200 for the user to clean and includes a base 110 , a first control valve 120 , a second control valve 130 and two water-spraying units 140 .
[0030] In this embodiment, the base 110 is secured on a toilet seat 210 of the toilet seat unit 200 . The base 110 includes a first space 111 , a second space 112 , a cold water hole 114 , a hot water hole 115 , a first outlet 116 and a second outlet 117 . The first space 111 is hollow and the second space 112 is communicated with the first space 111 via a guiding path 113 . The cold water hole 114 and the hot water hole 115 communicate with the first space 111 and are respectively coupled with a cold water tube A and a hot water tube B. The first outlet 116 and the second outlet 117 communicate with the second space 112 .
[0031] The first control valve 120 is secured in the first space 111 and includes a rotatable knob 121 , a ceramic valve core 122 and a temperature indication ring 123 . The ceramic valve core 122 is connected with the knob 121 and the temperature indication ring 123 is covered on the valve core 122 and includes various temperature scales. The inner structure of the valve core 122 is similar to the ceramic valve core of the single lever mixer. By rotating the valve rod of the valve core 122 to control the flow, temperature and the opening between the cold water hole 114 and the hot water hole 115 .
[0032] The second control valve 130 is secured in the second space 112 and includes a shaft 131 , a pulling block 132 , an upper blocking ring 133 , a lower blocking ring 134 and an elastomeric unit 135 . The shaft 131 is axially movable. The pulling block 132 is fastened on the shaft 131 and positioned out of the second space 112 . The upper blocking ring 133 is encircled in the middle of shaft 131 and corresponds to the first outlet 116 . The lower blocking ring 134 is encircled in the bottom of the shaft 131 and corresponds to the second outlet 117 . The elastomeric unit 135 is a bias spring and is set on the upper blocking ring 133 and against a top wall of the second space 112 . Normally, the upper blocking ring 133 encloses the first outlet 116 , and there is a drop between the lower blocking ring 134 and the second outlet 117 .
[0033] Refer to FIG. 1 and FIG. 3 . FIG. 3 illustrates a partial sectional view of a spraying tube of the water-spraying unit in FIG. 1 . The water-spraying units 140 are designed with different lengths and extended from the first outlet 116 and the second outlet 117 of the base 110 to the toilet seat unit 200 . The water-spraying units 140 respectively include a conduit 141 and a spraying tube 142 associated with the conduit 141 . The spraying tube 142 includes an immovable section 1421 , a movable section 1422 , a nozzle 1423 and a spring 1424 . The immovable section 1421 is connected with an end of the conduit 141 and located under the toilet seat 210 . The movable section 1422 is located in the immovable section 1421 and is movable axially. The nozzle 1423 includes multiple holes and is connected with an end of the immovable section 1421 . The spring 1424 is encircled on the movable section 1422 to provide resilience for the movable section 1422 after protruding elastically. Before the operation of the first control valve 120 , the movable section 1422 is covered in the immovable section 1421 to prevent from dejection attachment on the spraying tube 142 .
[0034] Refer to FIG. 2 . The user can see the predetermined temperature of the outputted water by the temperature indication ring 123 of the base 110 . Rotate the knob 121 clockwise or counter-clockwise to drive the valve rod of the valve core 122 to output water, and the cold water and the hot water are pumped into the first space 111 to mix to provide water at a desirable temperature. The mixed water is conducted to the second space 112 via the guiding path 113 and pumped to the short water-spraying unit 140 through the second outlet 117 . Refer to FIG. 4 . The movable section 1422 of the short water-spraying unit 140 is pushed by the water pressure to protrude outward and spray the mixed water for the user to clean. Rotate the knob 121 progressively to enlarge the opening of the valve core 122 , and the water pressure is increased such that the protruding length of the movable section 1422 is relatively extended (shown as the dotted line). Refer to FIG. 5 . When the pulling block 132 of the second control valve 130 is pulled upward, the shaft 131 is relatively moved upward and the first outlet 116 is opened (in this situation, the second outlet 117 is blocked by the lower blocking ring 134 ) to transfer the mixed water to the long water-spraying unit 140 . By spraying the mixed water with the long water-spraying unit 140 , it is convenient for female to clean in the menstrual period or pregnancy.
[0035] After adjusting the valve core 122 of the first control valve 120 in a closed state by rotating the knob 121 , the shaft 131 of the second control valve 130 is move downward through pressing against the upper blocking ring 133 with the resilience of the elastomeric unit 135 . The shaft 131 therefore returns to the position shown in FIG. 2 . In addition, the movable section 1422 of the water-spraying unit 140 is retracted into the immovable section 1421 with the resilience of the spring 1424 .
[0036] Refer to FIG. 6 . FIG. 6 illustrates a sectional view of the second embodiment of the water-spraying device. The water-spraying device of the second embodiment includes a base 150 , a temperature control valve 160 , a switch valve 170 and two water-spraying units. The temperature control valve 160 is secured on the first space 151 of the base 150 and the switch valve 170 is secured in the second space 152 of the base 150 . The water-spraying units are respectively linked with the first outlet 155 and the second outlet 156 of the base 150 .
[0037] The base 150 includes a first space 151 , a second space 152 , a cold water hole 153 , a hot water hole 154 , a first outlet 155 and a second outlet 156 . The first space 151 is communicated with the second space 152 . The cold water hole 153 and the hot water hole 154 communicate with the first space 151 and the first outlet 155 and the second outlet 156 communicate with the second space 152 .
[0038] Compared to the second control valve 130 in the first embodiment, the temperature control valve 160 has precise temperature-regulation but without a water-restraint function. The temperature control valve 160 includes a hollow cylindrical substance 161 , a cold water inlet 162 , a hot water inlet 163 , a water exit 164 , a modified rod 165 , an adjusting knob 166 , a bias spring 167 , a valve 168 and an adjuster 169 . The cold water inlet 162 , the hot water inlet 163 and the water exit 164 are defined through the wall of the substance 161 and extended to the first space 151 . The modified rod 165 is located in the substance 160 pivotally. The adjusting knob 166 is connected with an end of the modified rod 165 and positioned out of the base 150 . The bias spring 167 is encircled in the modified rod 165 . The valve 168 corresponds to the cold water inlet 162 and the hot water inlet 163 and is pressed against another end of the modified rod 165 . The adjuster 169 is located in the bottom of the substance 161 and has an end against the valve 168 . The adjuster 169 is made of a shape memory alloy and deformed with a ratio in accordance with the temperature difference between the outputted water temperature and the predetermined water temperature. Through the shape memory feature, the water temperature variation of the predetermined water temperature is lessened. The cold water inlet 162 and the hot water inlet 163 respectively correspond to the cold water hole 153 and the hot water hole 154 , and there are two filtering units respectively set in the cold water hole 153 and the hot water hole 154 to filter the impurity in the raw water.
[0039] The switch valve 170 includes a valve core 171 and a cap 172 wherein the outlet position of the valve core 171 is modified by rotating the cap 172 to control the flow and alter the flow direction. There are three water-outputted operation modes, outputted from the first outlet 155 , outputted from the second outlet 156 or closed both.
[0040] The opening ratio between the cold water inlet 162 and the hot water inlet 163 is adjusted by rotating the adjusting knob 166 to drive the modified rod 165 to move the valve 168 corresponding to the cold water inlet 162 and the hot water inlet 163 whereby the water temperature is modified. Moreover, the opening and the flow direction are controlled by the switch valve 170 to selectively drive the long water-spraying unit or the short water-spraying unit to spray the mixed water.
[0041] To prevent the temperature of the outputted water from being higher than the predetermined temperature such that the user is hurt by the over-heated water, the adjuster 169 of the temperature control valve 160 is expanded because of the heat to produce a force against to the elasticity of the bias spring 167 and the valve 168 is moved upward. Through this method, the hot water inlet 163 is abridged and the cold water inlet 162 is broadened such that the temperature of mixed water stored in the substance 161 is dropped. Contrarily, the valve 168 is moved downward to broaden the hot water inlet 163 and abridge the cold water inlet 162 to raise the mixed water temperature when the temperature of the outputted water is lower than the predetermined temperature. Therefore, the adjuster 169 variation is gradually reduced when the outputted water temperature is close to the predetermined water temperature until the predetermined water temperature is equal to the outputted water temperature.
[0042] Refer to FIG. 7 . In the third embodiment, the water-spraying device 100 is secured on the toilet seat unit 200 through a position seat 190 . The position seat 190 is locked to the toilet seat 210 by at least one groove 191 , and the spraying tube 142 of the water-spraying unit 140 is fastened at the bottom of the position seat 190 such that the position seat 190 is set between the toilet seat unit 200 and the toilet seat 210 .
[0043] As embodied and broadly described herein, the water-spraying device of the embodiment has the following effects:
[0044] 1. The water temperature and the spraying position are respectively modified in separated steps. In the first step, the temperature of the mixed water in the first space 111 is controlled via the first control valve 120 and the temperature control valve 160 . In the second step, the long water-spraying unit 140 and the short water-spraying unit 140 are driven via the second control valve 130 and the switch valve 170 in accordance with the spraying request of the different gender.
[0045] 2. The water pressure can be controlled by the first control valve 120 and the protrusive length of the movable section 1422 of the spraying tube 142 is altered based on the water pressure variation to adjust the nozzle 1423 spraying position.
[0046] 3. Because the water-spraying device is constructed with mechanical members, the manufacturing cost is reduced, the leakage problem is solved and the power consumption is reduced such that the product competitiveness is raised. In addition, the water-spraying device can be applied to various toilet seat unit to provide a convenient assembly.
[0047] Refer to FIG. 8 and FIG. 9 . The water-spraying unit of the fourth embodiment is a single spraying tube formation. The water-spraying device includes a base 310 , a control valve 320 and a water-spraying unit 330 .
[0048] The base 310 includes a cold water hole 311 , a hot water hole 312 and an outlet 313 wherein the cold water hole 311 and the hot water hole 312 can be respectively linked with the tubes.
[0049] The control valve 320 includes a valve core 321 , a shaft 322 , a water-division plate 323 , an aqueduct 324 and an aqueduct 325 . The valve core 321 is secured in the base 310 and is similar to the valve core 122 in the first embodiment. The water-division plate 323 is connected with the bottom of the shaft 322 . The aqueduct 324 corresponds to the cold water hole 311 and the hot water hole 312 , and the aqueduct 325 corresponds to the outlet 313 to control the opening and the flow between the cold water hole 311 and the hot water hole 312 .
[0050] The water-spraying unit 330 includes a conduit 331 associated with the outlet 313 and a spraying tube 332 associated with the conduit 331 and extended to the toilet seat unit. The spraying tube 332 is the same as the spraying tube in the first embodiment, so there is no more detailed description.
[0051] Rotate the shaft 322 of the valve core 321 clockwise or counter-clockwise to rotate the water-division plate 323 to vary the corresponding position between the aqueduct 324 , the aqueduct 325 , the cold water hole 311 , the hot water hole 312 and the outlet 313 . The water temperature emitted from the spraying tube 332 is higher when the overlapped opening for the hot water hole 312 is larger than the cold water hole 311 . Contrarily, the water temperature emitted from the spraying tube 332 is lower when the overlapped opening for the cold water hole 311 is larger than the hot water hole 312 . Moreover, the opening of the outlet 313 affects the flow and the protruding length of the spraying tube 332 is relatively controlled by the flow.
[0052] Although the present invention has been described in considerable detail with reference to certain preferred embodiments thereof, other embodiments are possible. Therefore, their spirit and scope of the appended claims should no be limited to the description of the preferred embodiments contained herein.
[0053] It will be apparent to those skilled in the art that various modifications and variations can be made to the structure of the present invention without departing from the scope or spirit of the invention. In view of the foregoing, it is intended that the present invention cover modifications and variations of this invention provided they fall within the scope of the following claims and their equivalents.
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An adjustable water-spraying device for a user to clean themselves after relieving themselves includes a base, a first control valve, a second control valve and at least a water-spraying unit. The base includes a first space and a second space communicating with each other. The first control valve is set in the first space to control the water temperature, and the second control valve is set in the second space. The water-spraying unit is attached in a water outlet of the base, and extended into toilet seat unit. Thus, the second control valve determines the opening or closing water outlet to drive one of the water-spraying units to spurt water and clean the users' anus.
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BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a video signal display system installed for a large number of seats arranged substantially in a matrix configuration, such as seats of an aircraft, train or a theater.
2. Description of the Related Art
In a vehicle, such as an aircraft, long-distance train or a long-distance bus, in which the passengers are compelled to be seated for a prolonged time, video services, such as presentation of motion pictures, television programs, video games or the information for sight-seeing or catalog shopping, are presented in order to relieve the passengers of boredom and to offer them the necessary information concerning the destination as well as to make them satisfied as to their travel. Such video services are offered by a picture display device, such as a liquid crystal monitor, built in the rear side of a back portion of a forward side seat.
The seat for an aircraft is designed according to a reclining seat system in which the back of the seat may be tilted in the fore-and-aft direction. If the passenger seated in the forward side seat adjusts the back of the seat, the screen built into the rearward portion of the seat back is changed in its position, so that the screen becomes difficult to view or occasionally becomes unusable. A seat for an aircraft provided with a television receiver which will overcome the above-mentioned problem is disclosed in JP KOKAI Utility Model Publication No. 54-105499, according to which both sides of a television receiver are rotatably supported by a rotary lever so that the television receiver may be tilted in the up-and-down direction.
With the above-described seat fitted with the television receiver, if the passenger seated in the forward side seat adjusts the back of the seat so that the position of the screen of the television receiver is changed, the television receiver may be adjusted in the up-and-down direction for adjusting the height position of the display screen with respect to the optimum line of sight of the viewer, so that the video services may be continuously received.
Meanwhile, the seat having a television receiver built into the rear side of the seat back has become available as a result of the debut of a liquid display device which is relatively thin and inexpensive and which is capable of constituting a large-sized display screen. However, the liquid crystal display unit exhibiting polarization characteristics present a problem that the screen is difficult to view depending on the angle of the line of sight of the viewer. Recently, group tours have become popular and there may be many instances in which passengers seated in neighboring seats have a conversation as they view the same screen. However, it may occur frequently that the picture displayed on the liquid crystal screen is difficult to view and the conversation cannot become lively.
The above-described seat provided with the television receiver is intended for personal use and cannot be adjusted for setting the display screen towards a mid position between the two neighboring seats. On the other hand, if the seats are arrayed in plural rows and there is left only a narrow space between the neighboring seats, it may occur that the picture displayed on the display screen of the picture display device of a seat disturbs or otherwise is not agreeable to the passenger seated in the neighboring seat.
OBJECT AND SUMMARY OF THE INVENTION
It is an object of the present invention to provide a video signal display system for use with a plurality of seats in which the direction of the display screen may be adjusted to the line of sight of the viewer and in which, even if the direction of the seat provided with the display system is changed, the direction of the display screen may be correspondingly changed in order to permit the viewer to view the screen at all times from an easy- to-view position.
The video signal display system according to the present invention has a plurality of picture display modules each having a display screen and each being arranged within a recess formed on the back surface of one of a plurality of seats so that the display screen may be viewed from the rear side of the seat, and means for pivotally supporting the picture display module with respect to the seat. The pivotal supporting means includes a spherical-shaped support and a rotation supporting fulcrum member in which the support is fitted.
One of the spherical-shaped support and the rotation supporting fulcrum member is secured on the bottom surface of the recess and the other is supported at a mid portion on the back surface of the picture display module.
The pivotal supporting means also includes a resilient supporting member secured to one of the bottom surface of the recess and the mid portion on the back surface of the recess to which the spherical-shaped fulcrum member is secured. The resilient supporting member is resiliently engaged with the outer peripheral surface of the fulcrum member.
If, with the video signal display system provided on the seat of the present invention, a passenger seated in a seat on the forward side of a seat in which a viewer is seated tilts the seat, or the viewer tilts his own seat, it suffices for the viewer to manually thrust upper or lower peripheral portions of a picture display device of the forward side seat in order to adjust the display screen of the picture display device so as to be matched to his or her line of sight. Similarly, if the same display screen is viewed by two passengers seated in neighboring seats, or if a viewer intends to avoid the situation in which the picture he or she is viewing might be disturbing to the neighboring passenger, it suffices for the viewer to manually thrust the left and right peripheral portions of the picture display device in order to adjust the screen position of the picture display device in the left-and-right direction. The control operations for the picture display device, such as channel switching or sound volume adjustment operations, may be performed from the seat of the viewer using a controller provided in the arm part of the seat.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG.1 is an exploded schematic perspective view of a seat provided with a picture display device according to the present invention.
FIG.2 is a schematic perspective view showing aircraft seats each provided with the picture display device.
FIG.3 is vertical cross-sectional view showing a seat provided with the picture display device, with the picture display device being set so that its display surface is parallel to the surface of the back.
FIG.4 is vertical cross-sectional view showing a seat provided with the picture display device, and showing the operation of vertically adjusting the display surface of the display device.
FIG.5 is a horizontal cross-sectional view showing a seat provided with the picture display device, with the picture display device being set so that its display surface is parallel to the surface of the back.
FIG.6 is a horizontal cross-sectional view showing a seat provided with the picture display device, and showing the operation of adjusting the display surface of the display device in the left-and-right direction.
DETAILED DESCRIPTION OF THE INVENTION
Referring to the drawings, preferred embodiments of the present invention will be explained in detail.
Referring to FIG. 1, a seat 1 provided with a picture display device according to the present invention is used as a seat for an aircraft or a long-distance train, in which a large number of such seats are arrayed in a larger number of rows so as to be neighboring to one another in the fore-and-aft and in the left-and-right directions. The seat 1 has a back 2 and both arm parts 3A and 3B and is designed as a reclining seat in which the back 2 may be inclined in the fore-and-aft direction at a suitable angle. The back 2 of the seat 1 has a pre-set thickness, and a liquid crystal monitor unit 10 for receiving picture services, such as motion pictures or tourist guides in the aircraft, is built on the back surface of the back 2, as will be explained later.
On a right arm part 3A of the seat 1, there is provided a lid 3a which may be opened about a hinge, not shown. Within a recess 3b of the arm part 3A, closed by the lid 3a, there is mounted a controller 4, such as a power switch, a channel changeover device or a volume adjustment device for the monitor unit 10, which is given herein as an example of the picture display device built into the back surface of the back 2. Although not shown, a headphone set device for the liquid crystal monitor unit 10 is also built into the seat 1.
The back surface of the back 2 of each seat 1 has a recess 5 in which the liquid crystal monitor unit 10 is built, as shown in FIG. 1. The recess 5 is generally rectangular with its longer side lying horizontally. A mounting plate 6, which is also rectangular in shape, with its longer side lying horizontally, is tightly mounted on the bottom surface of the recess 5 with set screws, not shown. A spherical-shaped support 7, having a spherical-shaped rotation supporting terminal fulcrum portion 7A and a resilient supporting member 8, formed by a resilient metal plate, are mounted on a mid portion of the major surface of the mounting plate 6.
The resilient supporting member 8 is shaped in the form of a letter U and is formed of, for example, a metal plate spring. The supporting member 8 is mounted so that a pair of resilient arms 8A and 8B thereof are disposed on both sides of the spherical-shaped rotation supporting terminal fulcrum portion 7A of the spherical-shaped support 7. The liquid monitor unit 10 is a small-sized monitor unit having a display surface 11 of 4 to 6 inches in size and is formed as one with a rotation supporting fulcrum member 12 in which the rotation supporting terminal fulcrum portion 7A is fitted in a manner which will be explained subsequently. The rotation supporting fulcrum member 12 is frusto-conical in shape and has an inner bore which, as shown in FIG.5, plays the role of a bearing surface by having a substantially semi-spherical profile corresponding to the spherical outer shape of the rotation supporting terminal fulcrum portion 7A. The spherical-shaped support 7 and the rotation supporting fulcrum member 12 make up a spherical-shaped supporting mechanism supporting the mid portion of the back surface of the liquid crystal monitor unit 10.
The rotation supporting fulcrum member 12 has its outside diameter slightly less than the horizontal distance between the resilient arms 8A and 8B of the resilient supporting member 8. Consequently, the liquid crystal monitor unit 10 is supported by the spherical-shaped support 7 by being assembled via the opening of the recess 5 so that the rotation supporting terminal fulcrum portion 7A of the spherical-shaped support 7 is fitted in the inner bore of the rotation-supporting fulcrum member 12 provided on the back surface of the monitor unit 10. With the liquid crystal monitor unit 10 being supported by the spherical-shaped support 7, the resilient arms 8A, 8B are resiliently engaged with both longitudinal lateral sides of the rotation-supporting fulcrum member 12. Thus the rotation-supporting fulcrum member 12, and hence the liquid crystal monitor unit 10, is maintained at a constant posture under the resiliency of the resilient supporting member 8.
The liquid crystal monitor unit 10 has its cable introduced through the inside of the back 2 of the seat 1 via a gap between the bottom surface of the recess 5 and the back surface of the liquid crystal monitor unit 10 so as to be connected to a picture supply unit or the controller 4 assembled into the right arm part 3A connected to a duct which is embedded in the floor.
A frame-shaped cover member 13 is fitted in the opening part of the recess 5 provided in the back 2 of the seat 1. The cover member 13 has its opening portion dimensioned so as to be slightly larger than the outer size of the liquid crystal monitor unit 10, so that, if the liquid crystal unit 10 is positioned with its front surface lying parallel to the back 2 of the seat 1, that is if its display surface 11 is directed forwards, a suitable gap is defined between the outer rim of the liquid crystal monitor unit 10 and the cover member 13, the front surface of the liquid crystal monitor unit 10 being substantially flush with the back 2.
With the above-described seat 1, by mounting the liquid crystal unit 10 within the recess 5 formed in the rear side of the back 2 so that the mid portion on the back surface of the unit 10 is supported by the spherical-shaped rotation supporting terminal fulcrum portion 7A of the spherical-shaped support 7 being fitted in the inner bore of the rotation-supporting fulcrum member 12 designed as a substantially semi-spherical bearing surface, the liquid crustal monitor unit 10 may be adjusted to an optimum position according to the state of the back 2 of the forward seat or according to the liking of the viewer.
That is, assuming that a number of seats 1A to 1D are arranged in plural rows and columns in adjacency to one another in the fore-and-aft and in the left-and-right directions, if a passenger seated in the seat 1B tilts the back 2B towards the rear, the screen 11 of the liquid monitor unit 10B is directed downwards, so that it is difficult to view from the rear side seat. If at this time the upper portion of the liquid crystal monitor unit 10B is thrust manually, the bearing surface 12A of the rotation-supporting fulcrum member 12 is slid on the outer periphery of the rotation supporting fulcrum portion 7A of the spherical-shaped support 7, against the bias exerted by the resilient arms 8A, 8B of the resilient supporting member 8 on the rotation supporting fulcrum member 12, so that the liquid crystal monitor unit 10 is rotated upwards with the spherical-shaped support 7 as a fulcrum point and hence the display surface 11 is adjusted to a position suited to the line of sight of the viewer.
Similarly, if a passenger seated in the seat 1C tilts the back 2B towards the front, as shown in FIG. 2, the display surface 11 of the liquid monitor unit 10C is directed upwards, so that it is difficult to view from the rear side seat. If at this time the lower portion of the liquid crystal monitor unit 10C is thrust manually, the liquid crystal monitor unit 10 is rotated downwards with the spherical-shaped support 7 as a fulcrum point against the bias exerted by the resilient arms 8A, 8B of the resilient supporting member 8 on the rotation supporting fulcrum member 12, by the above-described operation, as indicated by a chain-dotted line in FIG. 4, and hence the display surface 11 is adjusted to a position matched to the line of sight of the viewer.
On the other hand, if the passengers seated in adjacent seats 1A and 1B in FIG. 2 view the screen of the liquid monitor unit 10C built into the back 2C of the forward side seat 1C, the display surface 11 is difficult to view from the seat 1B. If at this time the right lateral side of the liquid crystal monitor unit 10C is thrust manually, the liquid crystal monitor unit 10 is rotated towards right with the spherical-shaped support 7 as a fulcrum point against the bias exerted by the resilient arms 8A, 8B of the resilient supporting member 8 on the rotation supporting fulcrum member 12, as in the case of the above-described operation in the vertical direction, as shown in FIG. 6, and hence the display surface 11 is adjusted to a position matched to the line of sight of the viewer.
Similarly, if the passengers seated in adjacent seats 1A and 1B in FIG. 2 view the screen of the liquid monitor unit 10D built into the back 2D of the forward side seat 1D, the display surface 11 is difficult to view from the seat 1A. However, by manually thrusting the left side portion of the liquid monitor unit 10D, the liquid monitor unit 10D is rotated towards left, with the support 7 as a fulcrum, as indicated by a chain line in FIG. 6. Thus the monitor unit 10D may be adjusted so that its display surface 11 is directed towards the passengers seated in the seats 1A and 1B.
The liquid crystal monitor unit 10 may be adjusted not only in the up-and-down and left-and-right directions, but also in oblique directions, by manually thrusting its four corners. After the liquid crystal monitor unit 10 is set so that its display surface 11 is at an optimum position, power turn-on, channel setting or sound volume adjustment may be made with the aid of the controller 4 built into the right arm part 3A of the seat 1, or picture services may be enjoyed using the headphone set.
With the above-described seat 1, the controller 4 taking charge of power turn on or channel switching is provided as a stationary unit in the recess 3b provided in the arm part 3. However, if radio troubles or the like hindrances are not produced, the controller 4 may be designed as a remote-control unit 4 provided in the recess 3b. The liquid crystal monitor unit 10 as a picture display unit may similarly be replaced by any suitable small-sized display unit.
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A video signal display system is provided at a back of each of a number of seats arranged in rows and columns. A recess is formed in the rear portion of the back of each seat and spherical-shaped support units for pivotally supporting a picture display unit of the display system are provided on the bottom of the recess and at a mid portion of the back surface of the picture display unit for assembling the picture display unit in the recess. The spherical-shaped supporting units are rotated for varying the position of the screen of the picture display unit built in the rear portion of the back of the seat to an easy-to-view position.
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BACKGROUND OF THE INVENTION
An internal combustion engine is primarily thought of as a device to propel a vehicle. The internal combustion engine, however, also serves as a source of power generation for subsidiary needs. The result of this dual function is, of course, the use of the internal combustion engine in a dual capacity. As the efficiency of design increases, this dual capacity is more frequently utilized. The requisite control systems for engines in vehicles were initially designed for transportation. As the use of internal combustion as a source of subsidiary power generation increases, there is a need to redesign the control systems to account for this secondary function.
A need has developed for a fast idle device for an internal combustion engine which operates in a failsafe fashion. A device is required which can, upon command, produce a second given idle speed at a rate which can be predetermined. As an example of these needs, consider an ambulance during operation. With the present idle control system devices, the power requirements of a potentially life saving machine might be higher than the engine is capable of producing at its normal idle speed, thereby stalling the engine and cutting off power entirely. Another example is the use of a vehicle which includes a hydraulically operated device where the engine speed must be high enough to develop hydraulic working pressure. In such a case the operator of the vehicle would prefer to have a second idle speed, which would fall in the desired R.P.M. range to develop the hydraulic pressure required.
One other particular concern for engine power is that it be available when necessary. Often a human operator is not available to change the idle speed of the engine. There exists a need for a fast idle device which can be either manually applied by the operator or automatically applied by a second machine which senses the condition of need. There also exists a need for a device which quickly and efficiently brings an engine up to a second predetermined idle speed.
SUMMARY OF THE INVENTION
The present invention is comprised of a throttle engaging ram arm, two means to provide the ram arm motion, and an electro-vacuum valve engaged either manually or automatically. One of the ram arm motive means is a diaphragm operated by using vacuum from the engine intake manifold. The other ram arm motive means is a solenoid operated by electrical current. A frame is provided for support and adjustment of the system.
The failsafe fast idle device of the present invention, by interacting directly with a throttle lever on a carburetor using a ram arm with two modes of motive engagement, enables the device to operate in the event of a vacuum failure. The ram arm is adjustable to allow the second idle speed to be set at any desired R.P.M. Thus, the failsafe fast idle device of the present invention applies a second idle speed at a preset level.
Therefore, it is an object of this invention is to provide a fast idle device which allows an operator to choose and apply a second preset idle speed.
It is another object of this invention to produce a fast idle device which is operated by redundant systems in the event of failure of one of the systems.
It is still another object of this invention to provide a fast idle device which quickly and efficiently brings an engine up to its preset idle speed.
It is yet another object of this invention to provide a fast idle device which is either manually (remotely) or automatically controlled.
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a perspective view of the present invention connected to a one barrel carburetor.
FIG. 2 is a partially cut away section of the solenoid/vacuum ram arm device.
FIG. 3 is a perspective view of the support and adjustment arrangement for the present invention.
FIG. 4 is a perspective view of the sliding mounting bracket of the present invention.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring initially to FIG. 1, an embodiment of the present invention 1 is shown in conjunction with a one barrel carburetor 3. The device is activated by manually closing a switch (not shown) at a remote location (e.g. dashboard), supplying electrical current through wire 5 to the electro-vacuum valve 7. Alternatively, this electrical current could be automatically supplied by a second device which senses its own need for increased power. When energized, a vacuum port within the electro-vacuum valve 7 opens. Vacuum from the engine intake manifold (15-18 in. Hg) is supplied to the electro-vacuum valve 7 through vacuum tube 9. The vacuum is allowed through the open vacuum port (not shown) within the electro-vacuum valve 7. This vacuum pressure is applied through vacuum tube 11 to the solenoid/vacuum ram arm device 13. A diaphragm 23 within the solenoid/vacuum ram arm device 13 deflects under the vacuum pressure, extending the ram arm 15. The ram arm contacts the throttle lever 17, which translates the axial motion of the ram arm to circular motion of the carburetor throttle rod 19. The throttle rod rotates the throttle blades (not shown) within the carburetor to increase the engine RPM.
The solenoid/vacuum ram arm device 13 is detailed in FIGS. 2 and 3. Vacuum is applied through tube 11 to the vacuum chamber 21. The diaphragm 23 flexes due to the pressure differential (atmospheric and vacuum). The ram arm 15 is mechanically connected to the diaphragm 23. The diaphragm 23 flexing motion is therefore translated to an axial motion of the ram arm 15. At the same time the current applied to the electro-vacuum valve 7 opens the vacuum port (not shown), electrical current is transferred from the electro-vacuum valve 7 through wire 25 to the solenoid/vacuum ram arm device 13. The current energizes the solenoid 27 portion of the solenoid/vacuum ram arm device 13. The solenoid 27 assists the diaphragm 23 in transmitting an axial motion to the ram arm 15. Once the ram arm 15 has reached the engaged position, the solenoid 27 acts as a holding coil to maintain the ram arm 15 in that position.
To disengage the device (i.e., allow the engine to return to normal idle), the operator opens the remote switch. This, in turn, cuts the current flow to the electro-vacuum valve 7. The vacuum port (not shown) closes, shutting off the flow of vacuum to the solenoid/vacuum ram arm device 13. As the pressure in the vacuum chamber 21 equalizes to atmospheric, spring 29 moves the diaphragm 23 and ram arm 15 back to the original, disengaged position. At the same time, current to the solenoid 27 is interrupted, losing the effect as a holding coil. When the ram arm 15 is no longer engaged, the carburetor throttle returns the engine to normal idle speed.
The engine speed achieved when the device is engaged is easily adjusted two ways. Coarse adjustment of speed is accomplished by the sliding mounting bracket 31 moving on the support bracket 33. This is further detailed in FIG. 3 and described below. Fine adjustment of speed is accomplished by turning the ram arm adjustment nut 35 which internally contacts the ram arm 15 in the solenoid/vacuum ram arm device 13.
FIG. 3 shows the support and adjustment arrangement for the solenoid/vacuum ram arm device 13. The support bracket 33 is rigidly attached to the carburetor 3. (see also FIG. 1). The support bracket is fabricated with two ears 37 bent at 90° containing oversize holes 38 drilled in line through each ear 37 to accept adjusting bolt 39. A spring 41 insures that no slack occurs between the support bracket 33 and the sliding mounting bracket 31. A retainer 43 on the adjusting bolt 39 keeps the bolt in position through the ears 37.
The sliding mounting bracket 31 is fabricated to provide several features, as shown in FIG. 4. The adjustment arm 45 is actually two parallel plates 47. Holes have been drilled and tapped 49 to engage the adjusting bolt 39. The sliding mounting bracket 31 also has a slotted hole 51. A bolt 53 passes through the slotted hole 51 in the sliding mounting bracket 31 to a round hole 55 in the support bracket 33 to maintain axial alignment during adjustment. A support ring 57 is provided to mount the solenoid/vacuum ram arm device 13 on the sliding mounting bracket 31.
Coarse adjustment is accomplished by turning the adjusting bolt 39 with a conventional wrench from either end. The bolt head 59 is conventional SAE guage. The opposite end (threaded end) 61 of the adjusting bolt 39 has been machined to also accept a conventional wrench. As the adjusting bolt 39 is turned, the tapped holes 49 in the adjustment arm 45 engage, translating the circular, adjusting bolt 39 motion to axial motion of the sliding mounting bracket 31. This, in turn, varies the extended position of the ram arm 15 with respect to the throttle lever 17. The difference adjusts the speed of the engine with the device engaged.
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A device for interacting with a throttle of a carburetor to produce a second, constant idle speed having a ram arm with a first end engaging the throttle when the ram arm is in a forward position; a vacuum-operable diaphragm attached to the ram arm for moving the ram arm to the forward position upon application of vacuum pressure; and solenoid-operated means for further maintaining the ram arm in the forward position.
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CROSS REFERENCE TO RELATED APPLICATION
[0001] This application claims priority from Japanese Patent Application No. 2005-033138, filed Feb. 9, 2005, the contents of which are hereby incorporated by reference into the present application.
TECHNICAL FIELD
[0002] This invention relates to an image forming apparatus forming an image by an electrophotographic method. More specifically, this invention relates to an image forming apparatus which enables adjustment of a state of an image, such as a color shift, by forming a pattern for image quality inspection and detecting the image quality inspection pattern.
BACKGROUND
[0003] Conventionally, an image forming apparatus including: a photoreceptor on whose surface an electrostatic image is formed responsive to light exposure; a light exposure unit for forming the electrostatic image on the surface of the photoreceptor by irradiating the photoreceptor with light; a development unit for developing the electrostatic image by depositing an developer on the electrostatic image formed on the surface of the photoreceptor; a belt member on which the developer deposited on the photoreceptor by the developing unit is conveyed, the belt member being in the form of an endless belt; a driving unit for rotationally driving the belt member a removal unit for removing the developer transferred on the belt member; a pattern formation unit for forming a pattern on the belt member; and a pattern detection unit for detecting the pattern formed on the belt member has been proposed.
[0004] In such an image forming apparatus, the light exposure unit forms the electrostatic image on the surface of the photoreceptor by irradiating the surface of the photoreceptor with light, and the developing unit develops the electrostatic image by depositing the developer on the electrostatic image. The developer used for developing the electrostatic image is transferred on the belt member which is rotationally driven by the driving unit and in the form of the endless belt. When a recording medium such as a sheet of paper is fed by placing the paper on a surface of the belt, the developer is transferred on the recording medium, thereby forming an image on the recording medium. Also, it is possible to form the image on the paper by conveying on the paper the developer which has been transferred on the belt member.
[0005] In the case where the image forming apparatus of the above-described type is provided with a plurality of photoreceptors for a plurality of colors of developers, lines which must be overlaid can sometimes be shifted from one another when the photoreceptors are misaligned. Accordingly, the pattern for image quality inspection (e.g. registration marks) is formed on the belt member by the pattern formation unit, so that it is possible to detect a degree of a color shift or the like by detecting the pattern by using the pattern detection unit. When the degree of the color shift or the like is detected, it is possible to perform excellent image formation by correcting a light exposure timing of the photoreceptor or the like in accordance with the color shift degree. The developer used for forming the pattern is usually removed by the removal unit after the detection by the pattern detection unit.
[0006] However, in such an image forming apparatus, a position of the pattern cannot be accurately detected in the case where a dust is deposited on the pattern to cause error or in the case where a noise is superimposed on a signal from a sensor during the pattern detection. Therefore, there has been proposed to increase accuracy of pattern position detection by detecting the pattern repeatedly by using a CCD having a plurality of pixels along a direction of conveyance of the pattern and moving the pattern by a very small distance (see, for example, JP-A-2000-19987). Also, there has been proposed to increase the pattern position detection accuracy by forming a pattern repeatedly and detecting the pattern repeatedly (see, for example, JP-A-2001-201896).
[0007] In the case of the apparatus of JP-A-2000-19987, a production cost of the apparatus is increased since the CCD having the plural pixel is required as the pattern detection unit. In the case of the apparatus of JP-A-2001-201896, a running cost of the apparatus is increased due to a waste of the developer since it is necessary to form the pattern repeatedly. Therefore, an object of this invention is to provide an image forming apparatus which enables the use of a simple sensor as the pattern detection unit and is capable of detecting a position of a pattern accurately without forming the pattern repeatedly.
SUMMARY
[0008] According to an aspect of the present invention, an image forming apparatus includes a photoreceptor which forms an electrostatic image on a surface responsive to light exposure, a light exposure unit which forms the electrostatic image on the surface of the photoreceptor by exposing the photoreceptor, a development unit which develops the electrostatic image by depositing a developer on the electrostatic image formed on the surface of the photoreceptor, a belt member which transfers the developer deposited on the photoreceptor by the developing unit, the belt member being in a form of an endless belt, a driving unit which rotationally drives the belt member, a removal unit which removes the developer transferred on the belt member, a pattern formation unit which forms a pattern on the belt member by controlling the light exposure unit, a pattern detection unit which detects the pattern formed on the belt member, a removal function stopping unit which prohibits removing the developer constituting the pattern by stopping a developer removal function of the removal unit before at least the developer constituting the pattern reaches a removal position of the removal unit or by maintaining a state in which the developer removal function is stopped when the pattern is formed on the belt member, and a drive control unit which causes the pattern detection unit to detect the pattern for a plurality of times by controlling the driving unit to rotate the belt member at least once when the pattern is formed on the belt member.
[0009] With such constitution, when the pattern for image quality inspection is formed on the belt member, the removal function stopping unit stops the developer removal function of the removal unit before the developer constituting the pattern reaches the removal position or maintains the removal function stopped state to prohibit the removal of the developer constituting the pattern. Also, when the developer removal function is stopped as described above, the drive control unit causes the pattern detection unit to detect the pattern for the plurality of times by controlling the driving unit in such a manner that the driving unit rotationally drives the belt member to cause the belt member to rotate at least once.
[0010] During the period in which the removal function stopping unit prohibits the removal unit from removing the developer, the pattern formed on the belt member remains on the same position on the belt member despite the rotation of the belt member, so that the pattern is detected by the pattern detection unit for the plural times. That is, though the pattern is formed only once and the pattern is detected by the pattern detection unit which performs detection of the only one point, this image forming apparatus detects the pattern for the plurality of times to thereby increase detection accuracy.
[0011] According to this embodiment, it is possible to use a simple sensor as the pattern detection unit; it is possible to accurately detect the position of the pattern without forming the pattern for a plurality of times; and it is possible to detect a color shift or the like without increasing a production cost or a running cost of the apparatus. Also, though a variation in pattern position can occur in the case of forming a plurality of patterns and detecting each of the patterns, this embodiment is free from such variation. Further, though a variation in detection ability can occur among the sensors (or pixels) in the case of using a pattern detection unit employing a multiple of sensors, this embodiment is also free from such variation. Furthermore, since it is unnecessary to rotate the belt member in a reverse direction as described later in this specification, it is possible to simplify a belt driving system.
[0012] Various modes maybe used for the removal function stopping unit in this embodiment, and the removal function stopping unit may stop the removal function or may maintain the removal function stopped state by separating the removal unit from the belt member or maintaining the state in which the removal unit is separated from the belt member. In the case of separating the removal unit from the belt member, it is possible to reliably prohibit the removal of the developer which constitutes the pattern. Therefore, in this case, there is achieved an effect of more reliably performing the pattern detection for the plurality of times.
[0013] Also, in this case, the removal function stopping unit may separate the removal unit from the belt member at a timing except for that during the pattern detection by the pattern detection unit. An error can occur during the pattern detection due to a vibration of the belt caused when the removal unit is separated from the belt member. Therefore, the pattern detection accuracy is further increased by separating the removal unit from the belt member at a timing other than that during the pattern detection.
[0014] According to another aspect of this invention, an image forming apparatus includes a photoreceptor which forms an electrostatic image on a surface responsive to light exposure, a light exposure unit which forms the electrostatic image on the surface of the photoreceptor by exposing the photoreceptor, a development unit which develops the electrostatic image by depositing a developer on the electrostatic image formed on the surface of the photoreceptor, a belt member which transfers the developer deposited on the photoreceptor by the developing unit, the belt member being in a form of an endless belt, a driving unit which rotationally drives the belt member, a removal unit which removes the developer transferred on the belt member, a pattern formation unit which forms a pattern on the belt member by controlling the light exposure unit, and a pattern detection unit which detects the pattern formed on the belt member. The removal unit is disposed at a position where the removal unit does not start removing the developer constituting the pattern until a pattern detection by the pattern detection unit is completed. The image forming apparatus further includes a drive control unit which when the pattern is formed on the belt member controls the driving unit to cause the belt member to rotate in a reverse direction at a timing after the completion of the pattern detection by the pattern detection unit and before the removal unit starts removing the developer constituting the pattern, and to cause the belt member to rotate the belt member in a positive direction after disposing the pattern short of a detection position of the pattern detection unit, thereby causing the pattern detection unit to detect the pattern for a plurality of times.
[0015] With such constitution, the removal unit is disposed at the position where the removal unit does not start removing the developer constituting the pattern until the pattern detection unit completes the pattern detection. The drive control unit controls the driving unit when the pattern is formed on the belt member in such a manner as described below. That is, the drive control unit causes the belt member to rotate in the reverse direction at a timing after the completion of the pattern detection by the pattern detection unit and before the removal unit starts the removal of the developer constituting the pattern so that the belt member rotates in the positive direction after the pattern is disposed short of the detection position of the pattern detection unit. With such driving control, the drive control unit causes the pattern detection unit to detect the pattern for the plurality of times.
[0016] As described above, even when the pattern is formed only once to be detected by the pattern detection unit which performs detection of the only one point, this image forming apparatus detects the pattern for the plurality of times thereby to increase detection accuracy, too. Therefore, according to this embodiment, it is possible to use a simple sensor as the pattern detection unit; it is possible to accurately detect the position of the pattern without forming the pattern for a plurality of times; and it is possible to detect a color shift or the like without increasing a production cost or a running cost of the apparatus.
[0017] Also, though a variation in pattern position can occur in the case of forming a plurality of patterns and detecting each of the patterns, this embodiment is free from such variation. Further, though a variation in detection ability can occur among the sensors (or pixels) in the case of using a pattern detection unit employing a multiple of sensors, this embodiment is also free from such variation. Furthermore, since it is possible to detect the pattern for the plurality of times without rotating the belt member for a plurality of times, it is possible to increase a pattern detection speed. Also, since it is unnecessary to use the removal function stopping unit, it is possible to simplify the constitution of the apparatus.
[0018] According to still another aspect of this invention, an image forming apparatus includes a photoreceptor which forms an electrostatic image on a surface responsive to light exposure, a light exposure unit which forms the electrostatic image on the surface of the photoreceptor by exposing the photoreceptor, a development unit which develops the electrostatic image by depositing a developer on the electrostatic image formed on the surface of the photoreceptor, a belt member which transfers the developer deposited on the photoreceptor by the developing unit, the belt member being in a form of an endless belt, a driving unit which rotationally drives the belt member, a removal unit which removes the developer transferred on the belt member, a pattern formation unit which forms a pattern on the belt member by controlling the light exposure unit, a pattern detection unit which detects the pattern formed on the belt member, a removal function stopping unit which prohibits removing the developer constituting the pattern by stopping a developer removal function of the removal unit before at least the developer constituting the pattern reaches a removal position of the removal unit or by maintaining a state in which the developer removal function is stopped when the pattern is formed on the belt member, and a drive control unit which when the pattern is formed on the belt member controls the driving unit to cause the belt member to rotate in a reverse direction after the completion of the pattern detection by the pattern detection unit, and to cause the belt member to rotate the belt member in a positive direction after disposing the pattern short of a detection position of the pattern detection unit, thereby causing the pattern detection unit to detect the pattern for a plurality of times.
[0019] With such constitution, the removal function stopping unit stops the developer removal function of the removal function before the developer constituting the pattern reaches the removal position of the removal unit or maintains the removal function stopped state to prohibit the removal of the developer constituting the pattern. Also, when the developer removal function is stopped as described above, the drive control unit causes the pattern detection unit to detect the pattern for the plurality of times by controlling the driving unit in such a manner as to cause the belt member to rotate in the reverse direction after the completion of the pattern detection by the pattern detection unit and to rotate in the positive direction after the pattern is disposed short of the detection position of the pattern detection unit.
[0020] As described above, even when the pattern is formed only once to be detected by the pattern detection unit which performs detection of the only one point, this image forming apparatus detects the pattern for the plurality of times thereby to increase detection accuracy, too. Therefore, according to this embodiment, it is possible to use a simple sensor as the pattern detection unit; it is possible to accurately detect the position of the pattern without forming the pattern for a plurality of times; and it is possible to detect a color shift or the like without increasing a production cost or a running cost of the apparatus.
[0021] Also, though a variation in pattern position can occur in the case of forming a plurality of patterns and detecting each of the patterns, this embodiment is free from such variation. Further, though a variation in detection ability can occur among the sensors (or pixels) in the case of using a pattern detection unit employing a multiple of sensors, this embodiment is also free from such variation. Furthermore, since it is possible to detect the pattern for the plurality of times without rotating the belt member for a plurality of times, it is possible to increase a pattern detection speed. Also, since this embodiment is free from restriction on the position of the removal unction stopping unit, it is possible to readily downsize the apparatus.
[0022] Various modes maybe employed also for the removal function stopping unit in this embodiment, and the removal function stopping unit may stop the removal function or may maintain the removal function stopped state by separating the removal unit from the belt member or maintaining the state in which the removal unit is separated from the belt member. In the case of separating the removal unit from the belt member, it is possible to reliably prohibit the removal of the developer constituting the pattern. Therefore, in this case, an effect of more reliably performing the pattern detection for the plurality of times is achieved.
[0023] Also, in this case, the removal function stopping unit may separate the removal unit from the belt member at a timing except for that during the pattern detection by the pattern detection unit. An error can occur during the pattern detection due to a vibration of the belt caused when the removal unit is separated from the belt member. Therefore, the pattern detection accuracy is further increased by separating the removal unit from the belt member at the timing other than that during the pattern detection.
[0024] The embodiment of switching between the directions of rotation of the belt member may further include a detaching unit for detaching the photoreceptor from the belt member when the drive control unit causes the belt member to rotate in the reverse direction. In this case, it is possible to more excellently prevent the photoreceptor from being damaged due to a contact with the belt member rotating in the reverse direction.
[0025] The embodiment of switching between the directions of rotation of the belt member may further include a photoreceptor reverse rotation unit for rotating the photoreceptor in the reverse direction when the drive control unit causes the belt member to rotate in the reverse direction. In this case, too, it is possible to more excellently prevent the photoreceptor from being damaged due to a contact with the belt member rotating in the reverse direction.
[0026] In the embodiment of switching between the directions of rotation of the belt member, the pattern detection unit may detect the pattern during a period in which the drive control unit causes the belt member to rotate in the reverse direction. In this case, since the pattern is detected when the belt is rotating in the reverse rotation, it is possible to further increase the pattern detection accuracy by increasing the number of pattern detections.
BRIEF DESCRIPTION OF THE DRAWINGS
[0027] FIG. 1 is a schematic sectional view showing an internal structure of a color laser printer to which this invention is applied;
[0028] FIG. 2 is a diagram for illustrating a structure of a toner removal unit of the printer;
[0029] FIG. 3 is a block diagram showing a constitution of a control system of the printer;
[0030] FIG. 4 is a flowchart showing a processing executed by the control system;
[0031] FIGS. 5A to 5 E are schematic diagrams showing an operation of the printer according to the processing;
[0032] FIG. 6 is a diagram illustrating a structure of a modification example of the toner removal unit;
[0033] FIG. 7 is a flowchart showing a modification example of the processing;
[0034] FIGS. 8A to 8 E are schematic diagrams showing an operation of the printer according to the processing.
[0035] FIG. 9 is a flowchart showing a modification example of the processing; and
[0036] FIGS. 10A to 10 E are schematic diagrams showing an operation of the printer according to the processing.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
[0037] Hereinafter, embodiments of this invention will be described with reference to the drawings. FIG. 1 is a schematic sectional view showing an internal structure of a color laser printer (hereinafter simply referred to as printer) 1 as an image forming apparatus to which this invention is applied.
[0038] The printer 1 shown in FIG. 1 has a toner image forming unit 4 , a sheet conveying belt 6 serving as a belt member, a fixing unit 8 , a sheet feeding unit 9 , a stacker 12 , and a control unit 10 and forms an image of four colors on a sheet P serving as a recording medium in accordance with externally input image data.
[0039] The toner image forming unit 4 is provided with four development units 51 Y, 51 M, 51 C, and 51 B each of which contains a toner T (equivalent to a developer; see FIG. 2 ). The colors of the toners T are yellow, magenta, cyan, and black. Each of the development units 51 Y, 51 M, 51 C, and 51 B is provided with a photosensitive drum 3 serving as a photoreceptor, a charger 31 for uniformly charging the photosensitive drum 3 , and a scanner unit 41 serving as a light exposure unit for forming an electrostatic image in accordance with the image data by irradiating a surface of the photosensitive drum 3 after the charging with laser light. Almost all of component parts of the scanner unit 41 are omitted in FIG. 1 , or, only a component part from which the laser light is emitted is shown in FIG. 1 .
[0040] Hereinafter, structures of the component parts will be described in detail. In the following description, an alphabet of any one of Y for yellow, M for magenta, C for cyan, B for black is added to a reference number when it is necessary to indicate the color. Such alphabet is omitted when it is unnecessary to indicate the color.
[0041] Each of the photosensitive drums 3 in the toner image formation unit 4 is rotatable and formed of a member having a substantially cylindrical shape, and the four photosensitive drums 3 are aligned at a substantially constant interval along a horizontal direction. As the member having a substantially cylindrical shape, a member having a substrate made from aluminum and a positively charged photosensitive layer formed on the substrate is used, for example. The substrate is grounded on a ground line of the printer 1 .
[0042] The charger 31 is a so-called scorotoron type charger and provided with a charging wire 32 facing to the photosensitive drum 3 and extending in a width direction of the photosensitive drum 3 and a shield case 33 housing the charging wire 32 and having an opening formed on a side thereof facing to the photosensitive drum 3 . The charger charges the surface of the photosensitive drum 3 (e.g. to +700V) by applying a high voltage to the charging wire 32 . The shield case 33 has a structure wherein a grid is provided at the opening facing to the photosensitive drum 3 , and the surface of the photosensitive drum 3 is charged to a potential substantially the same as a grid voltage by applying a predetermined voltage to the grid.
[0043] The scanner unit 41 is disposed on each of the photosensitive drums 3 at a position downstream from the charger 31 in a rotation direction of the photosensitive drum 3 . The scanner unit 41 emits the laser light from a light source for one color of the externally input image data to perform laser light scanning with the use of a mirror surface of a polygon mirror or the like which is rotationally driven by a polygon motor to irradiate the surface of the photosensitive drum 3 with the laser light.
[0044] When the scanner unit 41 irradiates the surface of the photosensitive drum 3 with the laser light according to the image data, a surface potential of the irradiated part is reduced (to +150 to +200 V) to form an electrostatic image on the surface of the photosensitive drum 3 .
[0045] Each of the development units 51 Y, 51 M, 51 C, and 51 B has a structure wherein the development case 55 housing the toner T is provided with a development roller 52 serving as a developer, and the development roller 52 is disposed at a position downstream from the scanner unit 41 with respect to the rotation direction of the photosensitive drum 41 in such a fashion as to contact the photosensitive drum 3 . Each of the development units 51 positively charges the toner T to supply the toner T as a uniform thin layer to the photosensitive drum 3 and causes the positively charged electrostatic image formed on the photosensitive drum 3 to carry the positively charged toner T at the contact part of the development roller 52 and the phoosentive drum 3 by the reverse development method, thereby developing the electrostatic image.
[0046] The development roller 52 is made from a base material such as an electroconductive silicone rubber and has a cylindrical shape, and a coating layer made from a resin containing fluorine or a rubber material is formed on a surface of the development roller 52 . The toner T housed in the development case 55 is a positively charged nonmagnetic one-component toner, and a yellow toner, a magenta toner, a cyan toner, and a black toner are housed in the development unit 51 Y, the development unit 51 M, the development unit 51 C, and the development unit 51 B.
[0047] A sheet feed unit 9 is disposed at a lowermost part of the apparatus and provided with a housing tray 91 for housing recording sheets P and a pickup roller 92 for feeding the recording sheets P. The recording sheets P housed in the housing tray 91 are fed from the sheet feed unit 9 one by one by the pickup roller 92 to be sent to a sheet conveying belt 6 via registration rollers 99 .
[0048] The sheet conveying belt 6 has a width which is narrower than that of the photosensitive drum 3 and is in the from of an endless belt so as to run integrally with the recording sheet P by carrying the recording sheet P thereon. The sheet conveying belt 6 is wrapped around a driving roller 62 and a driven roller 63 . Transfer rollers 61 are provided in the vicinity of the positions opposed to each of the photosensitive drums 3 in such a fashion as to sandwich the sheet conveying belt 6 . The sheet conveying belt 6 sequentially conveys the recording sheets P sent from the registration rollers 99 to the nips between the photosensitive drums 3 in such a fashion that a surface thereof opposed to each of the photosensitive drums 3 moves from the right hand side of the drawing to the left hand side of the drawing as shown in FIG. 1 by rotation of the driving roller 62 , thereby conveying the recording sheets P to the fixing unit 8 .
[0049] A cleaning roller 105 serving as a removal unit is disposed at a position where the sheet conveying belt 6 is turned around by the driving roller 62 and close to the driven roller 63 . Further, a detection sensor 11 serving as a pattern detection unit is provided at a position at which the detection sensor 11 is opposed to the sheet conveying belt 6 on the driving roller 62 . The detection sensor 11 may be a reflection type sensor having a light emitting unit and a plurality of light receiving units and distinguishing colors by a reflection angle of light (e.g. trade name GP2TC2 which is manufactured by Sharp, Co., Ltd.).
[0050] FIG. 2 is a diagram for illustrating a structure of the toner removal unit 100 provided with the cleaning roller 105 in detail. As shown in FIG. 2 , the cleaning roller 105 has a shaft member 105 a extending in a width direction of the sheet conveying belt 6 , and a foamed material made form silicone surrounding the shaft ember 105 a . The cleaning roller 105 is provided in such a fashion that it rotates with being in contact to the sheet conveying belt 6 when a predetermined bias is applied between the cleaning roller 105 and a metallic electrode roller 104 disposed at a position opposed to the cleaning roller 105 across the sheet conveying belt 6 . With this bias, the toner T deposited on the sheet conveying belt 6 is removed by the cleaning roller 105 . For instance, when the electrode roller 104 is connected to the ground line and a bias (e.g. −1200 V) having a polarity opposite to that of the toner T is applied to the cleaning roller 105 , the toner T is attracted by the cleaning roller 105 to be removed. The cleaning roller 105 is driven by a driving unit (not shown) in such a manner that a part of the cleaning roller 105 at which the cleaning roller 105 contacts the sheet conveying belt 6 is in a direction reverse to a direction in which the sheet conveying belt 6 is turned.
[0051] The cleaning roller is provided with a collection roller 106 made from a metal (such as a nickelized iron material or a stainless material) for removing the toner T adhered to the cleaning roller 105 and a retention box (retention container) 107 for retaining the toner T removed from the cleaning roller 105 . A cleaning blade 108 made from a rubber is abutted to the collection roller 106 to scratch off the toner T adhered to the collection roller 106 .
[0052] The above-described constitution of a portion from the cleaning roller 105 to the retention box 107 is housed in a housing 109 which is moved vertically by a solenoid 110 . Accordingly, the cleaning roller 105 contacts the sheet conveying belt 6 when the housing 109 is raised by shrinking of the solenoid 110 , while the cleaning roller 105 is detached form the sheet conveying belt when the housing is lowered by elongation of the solenoid 110 .
[0053] Referring back to FIG. 1 , the transfer roller 61 transfers the toner image formed on the photosensitive drum 3 on the recording sheet P conveyed by the sheet conveying belt 6 when a transfer bias (e.g. −10 to −15 μA) which has a polarity reverse is to that of the toner T is applied between the transfer roller 61 and the photosensitive drum 3 by a power source 112 of a negative voltage.
[0054] The fixing unit 8 is provided with a thermal roller 81 and a pressure roller 82 . The thermal roller 81 and the pressure roller 82 sandwiches the recording sheet P on which the toner image has been transferred as they convey the recording sheet P, so that the toner image is fixed on the recording sheet P by heating and pressurizing.
[0055] The stacker 12 is formed on a top face of the printer 1 . The stacker 12 is disposed at a discharge side of the fixing unit 8 to retain the recording sheets P discharged from the fixing unit 8 . The control unit 10 is provided with a controller using a known CPU 10 a (see FIG. 3 ) or the like as described later in this specification and controls an overall operation of the printer 1 .
[0056] The photosensitive drums 3 are held in such a fashion as to move upward so that the photosensitive drums 3 are detached from the sheet conveying belt 6 and positioned by a moving member 72 serving as a detaching unit provided in such a fashion as to stride the photosensitive drums 3 . The moving member 72 is formed of a plate-like member having a length sufficient for striding all of the photosensitive drums 3 and held in such a fashion as to move rightward and leftward in FIG. 1 . The moving member 72 is provided with four introduction holes 72 a extending in a horizontal direction and having a substantially clank shape, and shafts 3 a provided on a longitudinal side of the photosensitive drums 3 are fitted to the introduction holes 72 .
[0057] The moving member 72 is provided with a lifting motor 74 via a link 73 for converting a rotational force into a horizontal force, and the lifting motor 74 rotates responsive to an instruction signal from the control unit 10 to move the moving member 72 to right or left. When the moving member 72 is moved to the left, the shaft 3 a of each of the photosensitive drum 3 moves upward along the substantially clank shape of the introduction hole 72 a along with leftward movement of the introduction hole 72 a , so that the photosensitive drum 3 is detached from the sheet conveying belt 6 . In contrast, when the moving member 72 is moved to the right, each of the photosensitive drums 3 contacts the sheet conveying belt 6 . The image formation is normally performed in the state where the photosensitive drums 3 contact the sheet conveying belt 6 .
[0058] An operation of forming an image on recording sheets P in the printer 1 having the above-described constitution according to this embodiment is as follows.
[0059] One of the recording sheets P is supplied from the sheet feeding unit 9 by the pickup roller 92 , so that the recording sheet P is sent to the sheet conveying belt 6 via the transfer roller 98 and the registration rollers 99 . Next, the surface of one of the photosensitive drums 3 (photosensitive drum 3 Y) disposed at the rightmost position in FIG. 1 is uniformly charged by the charger 31 and then exposed to light by the scanner unit 41 based on externally input image data for yellow, so that an electrostatic image is formed as described above. Then, a yellow toner T which has been positively charged in the development unit 51 Y is supplied to the surface of the photosensitive drum 3 Y to perform development. The thus-formed toner image is transferred on the recording sheet P conveyed by the sheet conveying belt 6 by the transfer roller 61 to which the transfer bias has been applied.
[0060] The recording sheet P is then conveyed to positions at which the recording sheet P faces to the photosensitive drums 3 for magenta, cyan, and black in this order, so that toner images are formed on the surfaces of the photosensitive drums 3 in the same manner as in the yellow toner T. The toner images are transferred on the recording sheet P by the transfer roller 61 in an overlapping manner. The toner images of the four colors are fixed on the recording sheet P in the fixing unit 8 to be discharged on the stacker 12 .
[0061] In the printer 1 , registration marks RM (see FIGS. 5A to 5 E) are formed by using the four color toners on the sheet conveying belt 6 at initialization such as when the power is input or after a jam processing, so that the detection sensor 111 detects a state of the registration marks RM. Hereinafter, the detection processing will be described in detail.
[0062] FIG. 3 is a block diagram showing a constitution of a control system of the printer 1 . The control unit 10 is a microcomputer provided with the CPU 10 a, a ROM 10 b, a RAM 10 c , a backup RAM 10 d , an I/O port 10 e , and a bus 10 f for connecting the component parts 10 a to 10 e. A detection signal from the detection sensor 111 is input to the I/O port 10 e of the control unit 10 . Further, the I/O port 10 e outputs driving signals to the scanner unit 41 , the lifting motor 74 , and the solenoid 110 , driving signals to a belt motor 131 serving as a driving unit for driving the sheet conveying belt 6 via the driving roller 62 , and driving signals to a drum motor 132 serving as a photoconductor reverse rotation unit for driving the photosensitive drums 3 via driving circuits 141 , 142 , 143 , 144 , and 145 .
[0063] FIG. 4 is a flowchart showing a processing executed by the CPU 10 a based on a program stored in the ROM 10 b . When the processing is started, it is judged whether or not it is the initializing time such as when the power is input or after a jam processing in S 1 (S stands for step; the same applies to the following description). Since a reset signal or a signal representing a completion of the jam processing is input to the CPU 10 a , the above judgment is performed based on absence or presence of such input.
[0064] When it is not the initializing time (S 1 : NO), an ordinary processing such as image formation on the recording sheet P based on input data is performed in S 2 to terminate the processing. In turn, when it is the initializing time (S 1 : YES), the function of the cleaning roller 105 is stopped in S 3 . That is, the solenoid 110 is elongated to separate the cleaning roller 105 from the sheet conveying belt 6 .
[0065] In S 4 , when an instruction signal is sent to the belt motor 131 , a positive direction driving of the sheet conveying belt 6 is started. In SS, when instruction signals are sent to the scanner unit 41 and the drum motor 132 , registration marks RM are formed on the sheet conveying belt 6 . In S 6 , the registration marks RM are read via the detection sensor 111 .
[0066] When the reading of the registration marks RM is finished in S 6 , the process proceeds to S 8 to judge whether or not the reading was performed for a predetermined times (n times: n>2). In the case where the reading has not been performed for n times (S 7 : NO), the process returns to S 6 to perform the reading of the registration marks RM again.
[0067] Hereinafter, the processing of from S 3 to S 7 will be described using a block diagram of FIGS. 5A to 5 E. As shown in FIG. 5A , the cleaning roller 105 is separated from the sheet conveying belt 6 in S 3 . In S 4 , the rotation of the sheet conveying belt 6 is started, and the toners T are transferred from the photosensitive drums 3 Y, 3 M, 3 C, and 3 B to the surface of the sheet conveying belt 6 , so that the registration marks RM are formed. In FIGS. 5A to 5 E, parts corresponding to the colors of yellow, magenta, cyan, and black are represented by Y, M, C, and B.
[0068] As shown FIG. 5B , the registration marks RM are read when they are faced to the detection sensor 111 by the processing of S 6 . The sheet conveying belt 6 is continuously driven after the reading (see S 4 ), so that the registration marks RM are faced to the cleaning roller 105 as shown in FIG. 5C after facing to the detection sensor 111 . As described in the foregoing, since the cleaning roller 105 is separated from the sheet conveying belt 6 , the toners T constituting the registration marks RM are not removed and continues to rotate integrally with the sheet conveying belt 6 .
[0069] Then, as shown in FIG. 5D , the registration marks RM pass under the photosensitive drums 3 . Since the transfer bias has been applied to the photosensitive drums 3 , the toners T constituting the registration marks RM continue the rotation without being reversely transferred on the photosensitive drums 3 , so that the registration marks are read again by the detection sensor 111 as shown in FIG. 5E . In order to more excellently prevent a reverse transfer of the toners T in a state shown in FIG. 5D , an instruction signal for separating the photosensitive drums 3 from the sheet conveying belt 6 may be sent to the lifting motor 74 .
[0070] Referring back to FIG. 4 , when the registration marks RM have been read for n times (S 7 : YES), the sheet conveying belt 6 is stopped in S 8 , and then a color shift amount is calculated in S 9 to terminate the processing.
[0071] Any of known various calculation methods may be used for the calculation of the color shift amount in S 9 . It is possible to calculate a color shift amount of each of the registration marks RM read for the n times, and any of various methods described below may be used for obtaining a true color shift amount from the n color shift amounts. The methods may be a calculation of an average value of the n color shifts, a calculation of an average value of the n color shifts after eliminating an abnormal value, a calculation of an intermediate value of the n color shifts, a calculation of an intermediate value of the n color shifts after eliminating an abnormal value, and the like. A threshold value for detecting the abnormal value, i.e. a range of normal values, may be obtained by performing experiments and storing the experiment results as database in the backup RAM 10 d in advance of shipping of the printer. Further, when the processing of FIG. 4 is terminated after the calculation of the color shift amount in S 9 , the registration marks RM are removed by the cleaning roller 105 at a predetermined timing.
[0072] Thus, the registration marks RM are read by the one detection sensor 111 for the plurality of times in the printer 1 by separating the cleaning roller 105 from the sheet conveying belt 6 and rotationally driving the sheet conveying belt 6 to cause at least one rotation of the sheet conveying belt 6 . Therefore, the above-described plural times of reading are achieved without using a sensor having a multiple of pixels or forming the registration marks RM repeatedly, and the color shift or the like is excellently detected without increasing a production cost or a running cost of the apparatus.
[0073] Though the cleaning roller 015 is separated from the sheet conveying belt 6 in the printer 1 before the formation of the registration marks RM, it is sufficient that the cleaning roller 105 is separated from the sheet conveying belt 6 before the registration marks are faced to the cleaning roller 105 . However, the sheet conveying belt 6 can be vibrated when the cleaning roller 105 is separated from the sheet conveying belt 6 . Therefore, it is desirable that the cleaning roller 105 is separated from the sheet conveying belt 6 at a timing other than the formation or the reading of the registration marks RM.
[0074] Also, as a mode for stopping the function of the cleaning roller 105 , various modes other than the above-described one can be employed. For example, it is in some cases possible to prevent the removal of the registration marks only by stopping the bias applied between the electrode roller 104 and the cleaning roller 105 . Particularly, in the case of using a toner having a smoother surface, such as a polymerized toner, as the toner T, the removal of the registration marks is satisfactorily prevented only by the stop of bias application since such toner easily slips through the cleaning roller 105 .
[0075] FIG. 3 is a conceptual diagram for illustrating one example of constitution of a toner elimination unit 100 that enables the above bias adjustment. The toner elimination unit 100 is capable also of removing a negatively charged paper dust 90 from the sheet conveying belt 6 as described below.
[0076] As shown in FIG. 6 , the toner removal unit 100 is so formed as to change a polarity of the bias applied to the electrode roller 104 and the cleaning roller 105 in accordance with a switching of a cleaning bias changing switch SW 2 (hereinafter simply referred to as SW 2 ). The electrode roller 104 is connected to the ground line to be grounded. The cleaning roller 105 is selectively connected to the constant voltage source 114 or the constant voltage source 115 by the switch SW 2 .
[0077] In the case of removing the paper dust 90 from the sheet conveying belt 6 as shown in FIG. 6 , a bias (e.g. +600 V) having a polarity reverse to that of the paper dust 90 is applied from the constant voltage source 115 to the cleaning roller 105 . In the case of removing the toner T on the sheet conveying belt 6 , a bias (e.g. −1200 V) having a polarity reverse to that of the toner T is applied from the constant voltage source 114 to the cleaning roller 105 .
[0078] The collection roller 106 abutted to the cleaning roller 105 is rotated by a driving unit (not shown) or a driving of the cleaning roller 105 (interlocking with the cleaning roller 105 due to friction between the cleaning roller 105 and the collection roller 106 ) in such a fashion that of the cleaning roller 105 and the collection roller 106 rotate in an identical direction and at an identical speed at the contact part, and a bias voltage is applied from constant voltage sources 116 and 117 via a switch SW 3 to the collection roller 106 . As shown in FIG. 6 , in the case of removing paper dust, a bias (e.g. +800 V) having a polarity reverse to that of the paper dust 90 (positive polarity) is applied from the constant voltage source 117 to the collection roller 106 . In the case of removing the toner, a bias (e.g. −1600 V) having a polarity reverse to that of the toner T (negative polarity) is applied from the constant voltage source 116 to the collection roller 106 .
[0079] In either case of the paper dust removal and the toner removal, the bias is so adjusted as to make an attraction force of the collection roller 106 larger than that of the cleaning roller 105 , so that the paper dust 90 moves from the cleaning roller 105 to the collection roller 106 in the case of paper dust removal. The paper dust scratched off by the cleaning blade 108 is housed in the retention box 107 . Likewise, in the case of the toner removal, the toner T is moved from the cleaning roller 105 to the collection roller 106 , and the cleaning blade 108 scratches off the toner T to house the toner T in the retention box 107 . The switching between the switches SW 2 and SW 3 is performed in accordance with control signals sent from the control unit 10 ( FIG. 1 ), and the control unit 10 sends the signals to the switches SW 2 and SW 3 for switching to the constant voltage sources 115 and 117 in the paper dust removal, while sending the signals to the switches SW 2 and SW 3 for switching to the constant voltage sources 114 and 116 in the toner removal.
[0080] With such constitution of the toner removal unit 100 , the positive polarity bias is applied to the cleaning roller 105 in the same manner as in the paper dust removal in place of separating the cleaning roller 105 from the sheet conveying belt 6 in order to stop the function of the cleaning roller 105 .
[0081] Further, when processing to be performed by the control unit 10 is constituted as follows, it is possible to achieve an effect similar to that described above without stopping the function of the cleaning roller 105 . FIG. 7 is a flowchart showing another mode of the processing performed by the control unit 10 . In FIG. 7 , reference numerals are used for the process steps identical to those shown in FIG. 4 to omit detailed description of the process steps.
[0082] As shown in FIG. 7 , the process proceeds to S 4 without stopping the function of the cleaning roller 105 at the time of initialization (S 1 : YES) in this processing to start the driving for rotating the sheet conveying belt 6 in the positive rotation direction. The registration marks RM are formed (S 5 ), and the reading of the registration marks RM is terminated (S 6 ). Then, it is judged whether or not the reading was performed for a predetermined times (n times: n>2) (S 7 ), and the process returns to S 11 when the reading has not been performed for the n times (S 7 : NO).
[0083] In S 11 , an instruction signal is sent to the lifting motor 74 , so that the four photosensitive drums 3 are separated from the sheet conveying belt 6 . In S 12 , an instruction signal is sent to the belt motor 131 so that the sheet conveying belt 6 is rotated in the reverse direction. Since the sheet conveying belt 6 is started to rotate in the reverse direction immediately after the reading of the registration mark RM by the detection sensor 111 , the registration marks RM do not reach the cleaning roller 105 at this time point. Therefore, when the sheet conveying belt 6 is rotated in the reverse direction, the registration marks RM are faced to the detection sensor 111 bypassing above the detection sensor 111 along with the reverse rotation. Therefore, in S 13 performed subsequently to S 12 , the registration marks RM are read again by the detection sensor 111 , and then the sheet conveying belt 6 is driven to rotate in the positive direction again in S 14 after the reading by the detection sensor 111 . The process proceeds to S 6 after S 14 , so that the registration marks RM are read again. Thus, when the registration marks RM have been read for n times (S 7 : YES), the sheet conveying belt 6 is stopped (S 8 ), and then a color shift amount is calculated (S 9 ) to terminate the processing in the same manner as in the above-described processing.
[0084] The processing from S 4 to S 14 will be described by using a block diagram shown in FIGS. 8A to 8 E. Operations shown in FIGS. 8A and 8B are the same as those of the foregoing processing except for that the cleaning roller 105 is not separated from the sheet conveying belt 6 . That is, as shown in FIG. 8A , the driving of the sheet conveying belt 6 is started (S 4 ), so that as shown in FIG. 8B , the registration marks RM are formed on the surface of the sheet conveying belt 6 (S 5 ). The registration marks RM are then read when they are faced to the detection sensor 111 (S 6 ).
[0085] As shown in FIG. 8C , before the registration marks RM reach the cleaning roller 105 after the completion of the reading, the sheet conveying belt 6 is rotated in the reverse direction (S 12 ) as shown in FIG. 8D , so that the registration marks are faced to the detection sensor 111 bypassing above the detection sensor 111 along with the reverse rotation. The registration marks RM are read again when they pass above the detection sensor 111 from the reverse direction (S 13 ). During the reverse rotation, the photosensitive drums 3 Y to 3 B are separated from the sheet conveying belt 6 (S 11 ). Therefore, it is possible to prevent the photosensitive drums 3 from being damaged by the friction between the sheet conveying belt 6 rotating in the reverse direction and the photosensitive drums 3 . This damage prevention can be achieved also by rotating the photosensitive drums 3 in the reverse direction by sending an instruction signal to the drum motor 132 .
[0086] As shown in FIG. 8E , after the registration marks RM have been faced to the detection sensor 111 , the sheet conveying belt 6 is rotated in the positive direction again (S 14 ). Thus, in the same manner as in the above-described processing, the plural times of reading are achieved without using a sensor having a multiple of pixels or forming the registration marks repeatedly, and the color shift or the like is excellently detected without increasing a production cost or a running cost of the apparatus.
[0087] Also, since it is possible to read the registration marks RM for the plural times without causing the sheet conveying belt 6 to rotate once in this processing, it is possible to increase a processing speed. Further, since the photosensitive drums 3 are separated from the sheet conveying belt 6 , the registration marks are not reversely transferred on the photosensitive drums 3 even when the registration marks are moved to face the photosensitive drums 3 , as shown in FIG. 8E .
[0088] The function of the cleaning roller 105 may be stopped before the start of the driving of the sheet conveying belt 6 in this processing in the same manner as in the processing S 3 of FIG. 4 . In this case, the registration marks RM are prevented from being removed even when the registration marks RM are faced to the cleaning roller 105 . Further, in the case of stopping the function of the cleaning roller 105 , restriction on the position of the cleaning roller 105 is eliminated to enable easy downsizing of the apparatus.
[0089] Further, when processing to be performed by the control unit 10 is constituted as follows, it is possible to achieve an effect similar to that described above without stopping the function of the cleaning roller 105 . FIG. 10 is a flowchart showing another mode of the processing performed by the control unit 10 . In FIG. 10 , as in FIG. 7 , reference numerals are used for the process steps identical to those shown in FIG. 4 to omit detailed description of the process steps.
[0090] As shown in FIG. 9 , the process proceeds to S 4 without stopping the function of the cleaning roller 105 at the time of initialization (S 1 : YES) in this processing to start the driving for rotating the sheet conveying belt 6 in the positive rotation direction. The registration marks RM are formed (S 5 ), an instruction signal is sent to the lifting motor 74 , so that the four photosensitive drums 3 are separated from the sheet conveying belt in S 31 .
[0091] When the reading has not been performed for n times in S 7 (S 7 : NO), the reading of the registration marks is performed (S 6 ). After that, in S 32 , an instruction signal is sent to the belt motor 131 so that the driving direction of the sheet conveying belt 6 is reversed. Here, the reversing the driving direction means changing the belt rotation in the positive direction (S 32 =YES) to the reverse direction (S 34 ) and changing the belt rotation in the reverse direction (S 32 =NO) to the positive direction (S 34 ).
[0092] Since the driving direction of the belt is reversed immediately after the reading registration mark RM by the detection sensor 111 , the registration marks RM do not reach the cleaning roller 105 or the photosensitive drum at this point. When the reading has not been performed for n times in S 7 (S 7 : NO), the sheet conveying belt continue to be driven, and the registration mark RM are faced to the detection sensor 111 by passing above the detection sensor 111 along with the reverse direction. The registration marks RM are read again when they pass above the detection sensor 111 from a direction reverse to that of passing immediately before. The registration marks RM are read through the detection sensor 111 , and the reading is terminated. Then, the driving direction of the sheet conveying belt 6 is reversed in S 32 . Thus, when the registration marks have been read for n times (S 7 : YES), the sheet conveying belt 6 is stopped (S 8 ) as in the above-described processing, an instruction signal is sent to the lifting motor 74 , the four photosensitive drums 3 are pressed onto the sheet conveying belt 6 (S 35 ). Then a color shift amount is calculated (S 9 ), and the processing is terminated.
[0093] In the processing shown in FIG. 9 , the registration marks may be read arbitrary times larger than zero.
[0094] Further, the reading by the detection sensor 111 may be performed only when the belt is driven in the positive direction, and the reading may be performed only when the belt is driven in the reverse direction.
[0095] The processing from S 4 to S 35 will be described by using a block diagram show in FIGS. 10A to 10 E. Operations shown in FIGS. 10A and 10B are the same as those of the foregoing processing except for that the cleaning roller 105 is not separated from the sheet conveying belt 6 . That is, as shown in FIG. 1A , the driving of the sheet conveying belt 6 is started (S 4 ), so that as shown in FIG. 10B , the registration marks RM are formed on the surface of the sheet conveying belt 6 (S 5 ). The registration marks are then read when they are faced to the detection sensor 111 (S 6 ). After the registration marks RM are formed on the surface of the sheet conveying belt 6 , the photosensitive drums 3 Y to 3 B are separated from the sheet conveying belt 6 (S 21 ). Therefore, it is possible to prevent the photosensitive drums 3 from being damaged by the friction between the sheet conveying belt 6 and the photosensitive drums 3 during reading the registration marks in S 6 . This damage prevention can be achieved also by rotating the photosensitive drums 3 in the reverse direction by sending an instruction signal to the drum motor 132 .
[0096] As shown in FIG. 10C , before the registration marks RM reach the cleaning roller 105 after the completion of the reading, the sheet conveying belt 6 is rotated in the reverse direction (S 32 , S 33 , S 34 ) as shown in FIG. 10D , so that the rotation marks are faced to the detection sensor 111 by passing above the detection sensor 111 along with the reverse direction. Then, the registration marks RM are read again (S 6 ).
[0097] As shown in FIG. 10E , after the registration marks RM have been faced to the detection sensor 111 , the sheet conveying belt 6 is rotated in the positive direction again (S 32 , S 33 , S 34 ). Thus, in the same manner as in the above-described processing, the plural times of reading are achieved without using a sensor having a multiple of pixels or forming the registration marks repeatedly, and the color shift or the like is excellently detected without increasing a production cost or a running cost of the apparatus.
[0098] Also, since it is possible to read the registration marks RM for the plural times without causing the sheet conveying belt 6 to rotate once in this processing, it is possible to increase a processing speed. Further, since the photosensitive drums 3 are separated from the sheet conveying belt 6 , the registration marks are not reversely transferred on the photosensitive drums 3 even when the registration marks RM are moved to face the photosensitive drums 3 , as shown in FIG. 10E .
[0099] The function of the cleaning roller 105 may be stopped before the start of the driving of the sheet conveying belt 6 in this processing in the same manner as in the processing S 3 of FIG. 4 . In this case, the registration marks RM are prevented from being removed even when the registration marks RM are faced to the cleaning roller 105 . Further, in the case of stopping the function of the cleaning roller 105 , restriction on the position of the cleaning roller 105 is eliminated to enable easy downsizing of the apparatus.
[0100] In each of the above processing, S 3 is equivalent to the removal function stopping step, and S 4 and S 8 or S 4 , S 12 , S 14 , and S 8 are equivalent to the driving control step. Also, this invention is not limited to the above-described embodiments, and it is possible to practice various modes insofar as the practices do not deviate from scope of this invention. For example, the registration marks RM may be used for concentration adjustment, positioning, and like image formation state adjustments in addition to the detection of the color shift. Further, in printers where the function of the cleaning roller 105 is normally stopped so that the toner T is removed only in a particular case such as cleaning, it is possible to omit the process step of S 3 . The photoconductor may be a belt, and the belt member may be a so-called intermediate transfer belt.
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An image forming apparatus includes a photoreceptor which forms an electrostatic image on a surface, a light exposure unit which forms the electrostatic image on the surface, a development unit which develops the electrostatic image, a belt member which transfers a developer deposited on the photoreceptor, a driving unit which rotationally drives the belt member, a removal unit which removes the developer, a pattern formation unit which forms a pattern on the belt member, a pattern detection unit which detects the pattern, a removal function stopping unit which prohibits removing the developer by stopping a developer removal function before the developer reaches a removal position or by maintaining stopping the developer removal function, and a drive control unit which causes the pattern detection unit to detect the pattern for a plurality of times by controlling the driving unit to rotate the belt member at least once.
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