Abstract:
An ultrasonic device and method obtains desirable crimp connections between a crimp connector and a wire, or bundle of wires, by assessing the desirability of connections made in a wire-to-wire connection and in other situations where two materials with good acoustic propagation characteristics are joined together via deformation. An embodiment of the device as a crimping tool comprises a compressing means, pulse-generating circuitry, at least one ultrasonic transmitting transducer, at least one ultrasonic receiving transducer, receiving circuitry, and a display. The user may return to a previously crimped connection and assess the desirability of the connection by compressing the device about the connection, sending an acoustic signal through the crimp, and comparing the received signal to a signal obtained from known desirable connections.

Description:
CROSS-REFERENCE TO RELATED APPLICATION  
       [0001]     This application claims the benefit of U.S. Provisional Patent Application Ser. No. 60/550,740 filed on Mar. 2, 2004, the contents of which is incorporated herein by reference in its entirety. 
     
    
     ORIGIN OF THE INVENTION  
       [0002]     The invention described herein was made by employees of the United States Government and may be manufactured and used by or for the Government for governmental purposes without the payment of any royalties thereon or therefore. 
     
    
     BACKGROUND OF THE INVENTION  
       [0003]     The invention relates generally to a crimping tool, and more specifically to a crimping tool and method that uses acoustic signals to determine the desirability of connections between a crimp connector and a body such as a wire or bundle of wires.  
       BRIEF SUMMARY OF THE INVENTION  
       [0004]     An ultrasonic device and method obtains desirable connections between a crimp connector and a wire, hereafter known as crimp connections, for situations where two materials with good acoustic propagation characteristics are joined together via deformation. The crimping device comprises a compressing means, pulse-generating circuitry, at least one ultrasonic transducer means, receiver circuitry, and a display.  
         [0005]     The transducer means comprises a transmitter and a receiver that are coupled to a crimp compressing means such that pulsed electrical signals applied to the transmitter are converted to acoustic waves that propagate into the compressing means and through the materials being crimped. The acoustic waves then travel to the receiver where they are converted to electrical signals. These electrical signals are communicated to the operator of the crimp compressing means via the display.  
         [0006]     This embodiment enables comparison of the communicated electrical signals with signals that have been obtained for previous crimps that were determined to be desirable connections through destructive testing. A desirable connection is one where the applied compression produces sufficient stresses so that many body-to-connector connections are established. The permanent deformation of the crimp connector should be sufficiently large so as to assure substantial residual stresses after the release of the compressing means thereby maintaining good atom-to-atom intimacy between the connector and the body. If the communicated electrical signals do not match the signals of a desirable crimp connection, then motion of the compressing means continues until a match with a predetermined signal is made. Once the communicated signals do match that of a desirable crimp, then motion of the compressing means is stopped because a desirable crimp connection has been made. If no such match is ever achieved, the crimped connection is disposed of, and a new crimp connector should be used on a fresh section of wire.  
         [0007]     In another embodiment of the invention, the electrical signal generated by the receiving transducer for a predetermined and desirable crimp connection is stored in an electronic databank and compared to the communicated electrical signal using computational circuitry. The computational circuitry determines whether the received electrical signal approximates the predetermined crimp electrical signature within certain parameters. The operator is then able to determine when to stop compressing the crimping tool by observing a display. In one embodiment, electronic circuitry displays a red light when the communicated electrical signal does not match the predetermined signal within the outlined parameters and displays a green light when the communicated signal does match the predetermined signal.  
         [0008]     The same device can be used to determine the desirability of a crimp connection after its formation. The device is positioned such that the compressing means aligns with the deformation pattern on the compressed crimp connector. An ultrasonic coupling agent is applied to the compressed crimp connector and body, hereinafter called the crimp connection. The compressing means of the device is brought together in order to apply pressure to the crimp connection, but not so much pressure that additional deformation occurs. An acoustic signal is then sent through the crimp connection as outlined above. The acoustic signal is then received by a receiving transducer and converted to an electrical signal. The received signal is then compared with the signal generated when the crimp connection was originally made, compared with signals of crimp connections verified to be desirable through destructive testing, or a combination of these two comparisons to determine the desirability of the formed crimp connection. 
     
    
     BRIEF DESCRIPTION OF THE DRAWINGS  
       [0009]      FIG. 1  is a side view of a crimping tool in accordance with one embodiment of the present invention;  
         [0010]      FIG. 2  is a side view of the crimping tool of  FIG. 1  illustrating the compressing means in a compressed position;  
         [0011]      FIG. 3  is an isolated and simplified perspective view of the area outlined in  FIG. 1  by dotted line  3  showing an arrangement of the ultrasonic components and related circuitry in accordance with one embodiment of the invention;  
         [0012]      FIG. 4  is a perspective view of a punch member of the compressing means and some arrangements of the ultrasonic components and related circuitry in accordance with another embodiment of the invention;  
         [0013]      FIG. 5  is a perspective view of an anvil member of the compressing means and some arrangements of the ultrasonic components and related circuitry in accordance with another embodiment of the invention;  
         [0014]      FIG. 6  is a perspective view of the compressing means showing an arrangement of the ultrasonic components and related circuitry;  
         [0015]      FIG. 7  is a perspective view of the compressing means showing another arrangement of the ultrasonic components and related circuitry;  
         [0016]      FIG. 8  is a perspective view of a punch member of the compressing means and some arrangements of the ultrasonic components and related circuitry;  
         [0017]      FIG. 9  is a perspective view of an anvil member of the compressing means and some arrangements of the ultrasonic components and related circuitry;  
         [0018]      FIG. 10  is a perspective view of a punch member of the compressing means and some arrangements of the ultrasonic components and related circuitry in a pulse-echo configuration;  
         [0019]      FIG. 11  is a perspective view of a punch member of the compressing means and some arrangements of the ultrasonic components and related circuitry in a pulse-echo configuration;  
         [0020]      FIG. 12  is a simplified perspective view of a different embodiment of the compressing means;  
         [0021]      FIG. 13  is a simplified perspective view of an alternative compressing means and possible arrangements of the ultrasonic components and related circuitry;  
         [0022]      FIG. 14  is a simplified perspective view of a four-pronged compressing means and some possible arrangements of the ultrasonic components and related circuitry for another embodiment of the present invention;  
         [0023]      FIG. 15  is a simplified perspective view of the four-pronged compressing means and another alternative arrangement of the ultrasonic components and related circuitry;  
         [0024]      FIG. 16  is a simplified perspective view of the four-pronged compressing means and another alternative arrangement of the ultrasonic components and related circuitry;  
         [0025]      FIG. 17  is a simplified perspective view of the four-pronged compressing means and another alternative arrangement of the ultrasonic components and related circuitry; and  
         [0026]      FIG. 18  is a perspective view of the compressing means showing the positioning of the device for use in recertification. 
     
    
     DETAILED DESCRIPTION OF THE INVENTION  
       [0027]     Referring now to the drawings in detail, wherein like numerals indicate like elements throughout the drawings,  FIGS. 1 and 2  show a crimping tool in accordance with an embodiment of the present invention, designated generally by the numeral  5 . A pair of handles  51  and  61  are connected to, and allowed to rotate about, a coaxial pivot  110 . Jaws  30  and  40  are positioned opposite one another, with handle  51  being pivotally attached to jaw  40  at  81  and handle  61  being pivotally attached to jaw  30  at  71 . Guide pins  91  and  101  are secured on handles  51  and  61  respectively. Jaws  30  and  40  are provided with elongated slots  120  and  130  respectively, which extend longitudinally therealong and are disposed to engage guide pins  91  and  101 . Closure of handles  51  and  61  causes the handles to rotate about pivot  110  and effects closure of the jaws  30  and  40 . The pivot mounting of the jaws on the handles and cooperation of guide pins  91  and  101  with slots  120  and  130  respectively causes the jaws to maintain orientation to one another.  FIG. 1  illustrates the jaws  30  and  40  in the open position and  FIG. 2  shows the jaws  30  and  40  in a partially compressed position.  
         [0028]     As illustrated in  FIGS. 1 and 2 , crimping tool  5  includes compressing means  15 , which comprises a punch  10  and an anvil  20 . The punch and anvil as illustrated here is one example showing the structure of the compressing means; other structures providing the function of compressing would be within the scope of the invention.  
         [0029]      FIG. 3  is a representational view of the punch  10  and anvil  20  as seen from the dotted line  3  of  FIG. 1  and shows how the compressing means  15  engages a wire  90  and a crimp connector  100 . Although wire  90  has been illustrated as a single strand of wire, it may also comprise a plurality of strands or bundle of wires combining to form one body. Specifically, as the punch  10  and anvil  20  are brought together, they deform the crimp connector  100  about the wire  90  to provide both mechanical and electrical connections.  
         [0030]     Once the punch  10  and anvil  20  begin compressing the crimp connector  100 , an electrical signal  55 , in the form of a voltage spike, is sent from a pulse-generating circuit  70  through an electrical connection  50  to a transmitting transducer  35 . The electrical signal  55  activates the transmitting transducer  35  ultrasonically coupled to a non-operative surface of the punch  10 , which then transduces the electrical signal  55  into an acoustic signal  37 . Acoustic signal  37  may be in the ultrasonic frequency range, which is understood by the skilled artisan to be the range of frequencies above the audio-frequency range. The acoustic signal  37  then travels through the punch  10  and through the crimp connector  100 , through any contacts made by the compression between the crimp connector  100  and the wire  90 , through the wire  90 , through the opposing side of the crimp connector  100 , through the anvil  20  and to a receiving transducer  45  ultrasonically coupled to a non-operative face of the anvil  20 . This method of sending an acoustic signal from one side of the apparatus and receiving it at the opposing side is called a pitch-catch technique. The receiving transducer transduces the acoustic signals  47  received in the anvil  20  into an electrical signal  65  which is sent via an electrical connection  60  to receiver circuitry  80  for processing including amplification and analysis. An electrical signal  85  is the output of the receiver circuitry  80  and it is sent via electrical connection  82  to a display  84 .  
         [0031]     As the applied pressure increases and the crimp connector  100  deforms around the wire  90 , a number of points of contact, or asperities, between the wire  90  and the crimp connector  100  result. These points of contact enable increased ultrasonic transmission from the transmitting transducer  35  to the receiving transducer  45 . The number of pathways for ultrasonic transmission through the crimp connector  100  and wire  90  correspond to the number of pathways for electrical conduction. Once deformation of the connector  100  around the wire  90  is complete, a crimp connection between the connector  100  and the wire  90  is formed.  
         [0032]     One way of determining the desirability of the crimp connection (i.e. the mechanical strength and the amount of electrical transmission between the wire and the connector) is for the user to first make a series of test crimp connections using wire and crimp connectors similar to the ones to be used later for a desired application. The user records the output associated with each test crimp connection. The test crimp connections are then submitted to electrical testing and mechanical destructive pull testing to determine their electrical and mechanical characteristics. The recorded outputs associated with connections determined to be of desirable quality via testing are noted for future comparison with the outputs of the crimping tool generated later during its desired application. This technique thereby allows the user to assess the desirability of the crimp connection while it is being made. The comparison to be performed between the desired value and measured value during use of the crimping tool may be done by the operator of the tool, or it can be accomplished using electrical circuitry  80 .  
         [0033]     Because an acoustic signal may be sent through a crimp by several different methods, and because a wire and a crimp connector may be compressed by several methods, the foregoing and following descriptions are considered exemplary rather than exclusive. For example,  FIGS. 4-7  will describe various embodiments employing a pitch-catch technique for the acts of transmitting the acoustic signal and of receiving the acoustic signal for a crimping tool using a punch and an anvil.  FIGS. 8-11  will describe various embodiments employing the pulse-echo technique for the acts of transmitting and receiving acoustic signals, again for a tool using a punch and anvil.  FIGS. 13-17  indicate various embodiments employing both the pitch-catch and pulse-echo techniques for embodiments employing four compressing members.  
         [0034]     Referring now to  FIG. 4 , the transmitting transducer  35  may be positioned on any non-operative (i.e., non-compressing) face of the punch  10 . Additionally, the device may comprise multiple transmitting transducers  35   a - e . Multiple independent pulse-generating circuits  70   a - e  may all independently send electrical signals  55   a - e  through electrical connections  50   a - e , respectively, to their corresponding transmitting transducers  35   a - e  or may be connected in a manner that allows for one set of pulse-generating circuitry  70  to send a respective electrical signal  55  to all the transmitting transducers simultaneously (not shown).  
         [0035]     Referring to  FIG. 5 , the receiving transducer  45  may be positioned on any non-operative (i.e., non-compressing) face of the anvil  20 . Additionally, the device may comprise multiple receiving transducers  45   a - e . The multiple receiving transducers  45   a - e  may all be connected separately via their respective electrical connections  60   a - e  to separate receiving circuitry  80   a - e , respectively, or transducers  45   a - e  may all be connected in a manner that allows for one set of receiver circuitry  80  (not shown) to process the respective electrical signals  65   a - e  sensed by the receiving transducers  45   a - e  simultaneously.  
         [0036]     In another embodiment, the transmitting transducer  35  and the receiving transducer  45  are not positioned directly opposite one another such that the path of travel of the acoustic signal  37  propagates directly onto the receiving transducer as illustrated in  FIG. 3 . Instead, as shown in  FIGS. 6 and 7 , the transmitting transducer  35  and receiving transducer  45  may be positioned such that acoustic signals  37  are sent transversely across the wire  90  and crimp connector  100  rather than substantially in a straight line. Nevertheless, such positioning still employs a pitch-catch technique for transmitting and receiving the acoustic signal.  
         [0037]     Even though the illustrations to this point have consistently shown the transmitting transducer  35  on the punch  10  and the receiving transducer  45  on the anvil  20 , the positioning of the transmitting transducer  35  and the receiving transducer  45  may be vice versa, (i.e., the transmitting transducer  35  may be positioned on the anvil  20  and the receiving transducer  45  may be positioned on the punch  10 ).  
         [0038]     Another example of positioning for the transmitting transducer  35  and receiving transducer  45  is illustrated in  FIG. 8 , where both the transmitting and receiving transducers,  35  and  45  respectively, are located on the punch  10 . In such a configuration, an acoustic signal  37  is sent from the transmitting transducer  35  through the punch  10  and through the connections between the crimp connector  100  and wire  90 , and to the anvil  20 . The acoustic signal  47  then bounces or echoes back from the anvil  20 , travels once more through the connections between the crimp connector  100  and the wire  90 , and is received by the receiving transducer  45 . This method for sending an acoustic signal from one end of the apparatus, having it travel through the crimp connection, bounce back from the opposing compressing means and to travel back through the crimp connection, and then having it received at the same end of the apparatus as it was sent from is called a pulse-echo technique. Once at the receiving transducer the acoustic signal is converted to an electrical signal  65  which is sent via electrical connection  60  to the receiver circuitry  80 . After amplification and analysis of signal  65 , another electrical signal  85  is sent via electrical connection  82  for display by device  84 .  
         [0039]     Another example of positioning of the transmitting transducer  35  and receiving transducer  45  is illustrated in  FIG. 9 , where both the transmitting and receiving transducers,  35  and  45  respectively, are located on the anvil  20 . In such a configuration, a pulse-echo technique would be used to send an acoustic signal  37  from the transmitting transducer  35  through the anvil  20  and through the connections between the crimp connector  100  and wire  90 , and to the punch  10 . The acoustic signal  47  would then bounce or echo back from the punch  10 , travel once more through the connections between the crimp connector  100  and the wire  90 , be received by the receiving transducer  45 , and be converted to an electrical signal  65  sent via electrical connection  60  to the receiver circuitry  80 . After analysis and amplification of signal  65 , another electrical signal  85  is sent via electrical connection  82  to be displayed by device  84 .  
         [0040]     In another embodiment, rather than having two separate transducers  35  and  45 , the device may use one ultrasonic transducer that functions as both the transmitting transducer  35  and the receiving transducer  45 . For example,  FIG. 10  shows one transducer positioned on punch  10  for transmitting acoustic signal  37  and receiving acoustic signal  47 .  FIG. 11  shows one transducer positioned on anvil  20  for transmitting acoustic signal  37  and receiving acoustic signal  47 . Both of these embodiments would use a pulse-echo technique similar to what was described in the text relating to  FIGS. 8 and 9 .  
         [0041]     The compressing means  15  need not be wedge-shaped. If the compressing members  10  and  20  are capable of deforming the crimp connector  100  about the wire  90 , they are suitable for this embodiment. For example,  FIG. 12  demonstrates the compressing means  15  with a flat or block shaped punch  10  and a flat or block-shaped anvil  20 . Other contact surfaces such as round, jagged, triangular, etc. may also be used.  
         [0042]     Rather than the compressing means  15  comprising two bodies such as a punch and an anvil, the compressing means  15  may also comprise any number of compressing bodies. One example is a configuration that comprises four punches  210   a ,  210   b ,  210   c , and  210   d  as illustrated in  FIG. 13 .  
         [0043]     The four-punch system  125  is subject to the same variations in positioning of the transducer components discussed previously for system  25 .  FIG. 13  illustrates a system comparable to that described in  FIGS. 4 and 5  where at least one transmitting transducer  35  sends an acoustic signal  37  to be received by multiple receiving transducers  45   a - c . Each receiving transducer  45   a - c  then transduces the received acoustic signal  47   a - c  to an electrical signal  65   a - c  that is sent via the respective electrical connection  60   a - c  either to independent receiver circuitry  80   a - c  or to a central set of receiver circuitry  80  (not shown) to be analyzed and amplified before being sent via respective electrical connections  82   a - c  to displays  84   a - c , or combined to be displayed on a single display  84  (not shown).  
         [0044]     Referring to  FIG. 14 , the four-punch system  125  may also be configured with two transmitting transducers  35   a ,  35   b  respectively positioned on two independent compressing members  210   a ,  210   b  and paired with two receiving transducers  45   a ,  45   b  respectively positioned on two compressing members opposite its respective transmitting transducers.  
         [0045]     The four-punch system  125  may also be configured with three transmitting transducer  35   a ,  35   b ,  35   c  respectively positioned on independent compressing members  210   a ,  210   b ,  210   c  and one receiving transducer  45  positioned on the remaining compressing member  210   d  as illustrated in  FIG. 15 .  
         [0046]     Another embodiment of the four-punch system  125  is illustrated in  FIG. 16 . This embodiment is comparable to the system described for  FIGS. 6 and 7  where the signal is sent transversely rather than longitudinally (in a straight line) through the crimp connection.  
         [0047]     The four-punch system  125  may use the pulse-echo technique displayed in  FIG. 17 , which operates in a manner similar to the systems of  FIGS. 10 and 11  described previously.  
         [0048]     As illustrated in  FIG. 18 , an embodiment of this invention may also be used to recertify the desirability of a crimp connection after its formation.  FIG. 18  shows the punch  10  and anvil  20  aligned with a deformation pattern  42  on the outer surface of the crimp connector  100 . This deformation pattern is formed by the compressing means  15  during the initial crimping process. It may be a deep groove, a series of indentations, etc. An ultrasonic coupling agent  43  is applied to the outer surface of the deformed crimp connector  100 . The punch  10  and anvil  20  are brought together in order to apply pressure to the deformed crimp connector  100  and wire  90 , but not so much pressure that additional deformation occurs. An acoustic signal  37  is then sent by the transmitting transducer  35  through the punch  10 , the crimp connector  100 , the wire  90 , out the other side of the crimp connector  100 , and into the anvil  20 . The acoustic signal  47  is received by a receiving transducer  45  and converted to an electrical signal  65 . The electrical signal  65  may be compared with the signal received when the crimp connection was originally made. This comparison is accomplished via electrical circuitry  80 , done manually by the operator, or a combination of the two.  
         [0049]     In an alternative embodiment of use for recertification, the electrical signal  65  is compared with signals of crimp connections considered to be desirable through destructive testing.  
         [0050]     A further embodiment uses a combination of these two techniques to verify the continuing desirability of the crimp connection.  
         [0051]     While a system having a punch  10  and anvil  20  has been illustrated for use in recertification, the same process for recertification would apply for other configurations of the compressing means, such as, for example, a four-punch system.  
         [0052]     Although only a few exemplary embodiments of this invention have been described in detail above, 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 following claims. In the claims, means-plus-function and step-plus-function clauses are intended to cover the structures or acts described herein as performing the recited function and not only structural equivalents, but also equivalent structures. Thus, although a nail and a screw may not be structural equivalents in that a nail employs a cylindrical surface to secure wooden parts together, whereas a screw employs a helical surface, in the environment of fastening wooden parts, a nail and a screw may be equivalent structures.