Abstract:
A compound indenter for a wire connector pin, the pin having an axial length and an opening at an end thereof for receiving a wire having an exposed portion and an insulation covered portion, the opening being sized to receive both the exposed portion and a length of the insulation covered portion comprises a first indenter having a plurality of indenting elements for engaging the pin in an axial location overlaying the exposed portion of the wire inserted in the pin and a second indenter having a plurality of indenting elements for engaging the pin in an axial location overlaying the insulation covered portion of the wire inserted in the pin. The apparatus advances the indenting elements of each of the first and second indenters generally concurrently for compressing respective sections of the pin into engagement with the exposed wire portion and the insulation covered portions of the wire.

Description:
SPECIFIC DATA RELATED TO THE INVENTION 
   This application claims the benefit of U.S. provisional application No. 60/406,520, filed Aug. 28, 2002 and U.S. provisional application No. 60/448,043 filed Feb. 20, 2003. 

   BACKGROUND OF THE INVENTION 
   The present invention relates to a crimping tool for pin and socket contacts and more particularly, to a tool for crimping a pin at two separate distinct locations in which the pin has a different diameter at each location. 
   Connectors used for aircraft applications generally comply with military specifications (mil spec) standards which require waterproof connectors that utilize a plurality of male and female pins in opposite ends of a mating connector pair to complete electrical connections between wire leads or conductors connected to the connector pair. Typically, the pins are small diameter elements that are replaceable in each of the mating connector pairs. A typical male pin has an end portion that is generally solid and a rear portion which is hollow and designed to receive a bare or stripped wire of a conductor connected to the pin. Such pins generally require only a single crimp in order to fasten the pin to the conductor. 
   In a new application in which weight is a factor, the conventional copper wire conductors have been replaced by aluminum wire conductors. One problem that exists with aluminum wire conductors is that exposure of the conductor to moisture may result in corrosion of the aluminum wire. Consequently, it has been determined that the use of aluminum conductors requires that the insulating material over the conductor be inserted into the contact pin and crimped in place in order to provide a secure seal and preclude introduction of moisture onto the aluminum conductor where the insulation is stripped to allow electrical contact between the conductor and the pin. This requirement has resulted in a redesign of such contact pins so that the pins designed for this application have a dual diameter conductor receiving end so that the aluminum conductor can be stripped over a portion of its length for insertion into the pin while allowing a portion of the insulation on the conductor to also be inserted into the pin and the pin crimped on the insulation to thereby provide a seal to preclude moisture entry around the conductor. As a result of this redesign in pin structure, it has become necessary to provide a crimping tool which is capable of not only crimping the pin about the wire conductor portion but also crimping an enlarged portion of the pin about the insulation on the aluminum conductor. Furthermore, it is important to provide a crimping mechanism which completely crimps the pin about the conductor insulation in such a manner that moisture is precluded from entering around the pin to conductor coupling. 
   SUMMARY OF THE INVENTION 
   The present invention is directed to a new form of indenter for crimping an open end of a connector pin about an insulation covered wire in order to minimize intrusion of moisture into the pin to prevent oxidation of the wire attached to the pin. In one form, the invention comprises a compound indenter having a first indenter section for crimping an outer open end of the connection pin about the insulation and a second indenter section for crimping or indenting the pin so as to connect the pin to a metallic wire. In an illustrative example, the first indenter section utilizes a pair of opposed indenter elements having facing flat anvil surfaces and a second pair of opposed indenter elements having facing arcuate anvil surfaces. The first pair of flat surfaces are driven into contact with the open end of the pin to cause the open end to first deform into a generally oval configuration. Subsequently, the second pair of indenter elements having arcuate surfaces are driven into contact with the open end of the pin in a direction normal to the plane of the first pair of flat surfaces. The arcuate anvil surfaces compress the open end of the pin into a generally circular configuration while the flat surfaces prevent the open end of the pin from expanding outwardly during the compression cycle. The dual action of the two sets of indenter elements thus deform the open end of the pin into a generally circular configuration which fits tightly about the insulation covered wire inserted into the pin. 
   A second indenter section includes a plurality of indenter elements that are driven into contact with the pin concurrently with the elements of the first section so that the pin is indented at multiple locations to cause the pin to be crimped onto the non-insulation covered portion of the wire inserted into the pin. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     The features and advantages of the present invention will become apparent from the following detailed description of the invention when read with the accompanying drawings in which: 
       FIG. 1  is a schematic representation showing the location of a pair of indenters for crimping the pin at two spaced locations; 
       FIGS. 2   a – 2   c  illustrate a sequence of crimping actions for crimping an end of the connector pin of  FIG. 1  about insulation on a wire; 
       FIG. 3  illustrates one form of pneumatically-operated tool for implementing the indenting/crimping functions in accordance with one form of the present invention; 
       FIG. 4  illustrates one form of hand tool with which the present invention may be used; and 
       FIGS. 5   a – 5   d  and  FIGS. 6   a – 6   d  illustrate corresponding indenter element positions of each of a pair of indenters in a single tool. 
   

   DETAILED DESCRIPTION OF THE INVENTION 
     FIG. 1  illustrates a design of one form of connector pin  10  (sometimes referred to as a contact) having a contact tip  12  and a hollow portion  14  for receiving a nickel-plated aluminum conductor  16  from which insulation has been stripped and for receiving a length of conductor from which the insulation material  18  surrounding the conductor  16  has not been stripped. As can be seen, the open end  14   a  of the pin portion  14  has a larger diameter opening to allow the insulation material  18  to be inserted at least partially within the portion  14 .  FIG. 1  also shows the position of a first indenter  20  which is designed to crimp the pin  10  in a conventional manner so as to capture and hold the conductor  16  within the hollow portion  14 . Positioned adjacent the portion  14   a  of the pin  10  is a second indenter  22  which is designed to crimp the portion  14   a  about the insulation  18  on the conductor  16 . The indenter  22  is uniquely designed to assure that all sides of the portion  14   a  tightly encompass the insulation  18  to minimize moisture intrusion into the connector pin and potential corrosion of the exposed conductor  16 . 
   Turning now to  FIGS. 2A–2C , there is shown an exemplary embodiment of one form of indenter  22  that may be used to provide the crimping of the section  14   a . As shown in  FIG. 2A , the indenter  22  comprises two flat tip indenter elements  24 , sometimes referred to an anvils. These two indenter elements  24  are designed with flat anvil surfaces to first engage the connector pin portion  14   a  and to cause that pin portion to deform into the oval shape shown in  FIG. 2B . The indenter elements  24  thus bring two sides of the connector pin portion  14   a  into abutting relationship with the insulation material  18 . Thereafter, a second set of indenter elements  26  having arcuate anvil surfaces are brought into contact with the section  14   a  as shown in  FIG. 2C  so as to compress the remainder of the section  14   a  into constriction about the insulation  18 . The indenter elements  24  remain in position while the indenter elements  26  are compressed toward pin  10  so as to prevent the contact portion  14   a  from deforming in another direction. While the result of this form of crimping action may not produce a uniformly smooth connection between the section  14   a  and insulation  18 , the material of the contact is pressed against and into the insulation  18  with sufficient force to provide the moisture proof coupling as necessary to preclude or minimize moisture intrusion into the connector pin and causing corrosion of the aluminum conductor  16 . 
     FIG. 3  illustrates one form of tool head  30  for use as a compound indenter incorporating the indenters  20 , 22  discussed above. Head  30  includes a circular base plate  32  having a central aperture  34  for passage of an actuating rod (not shown). A housing section  36  is attached to base plate  32  and provides both a covering and a support for the indenters  20 , 22  and associated actuating mechanism. The indenter  20  comprises the indenter elements  38  mounted within a circular opening  40  in pivotable actuator  42 . The opening  40  has an inner surface  44  which functions as a camming surface in contact with distal ends of the indenter elements for driving the indenter elements  38  radially inward when the surface  44  is rotated about a center of the opening  40 . The camming surface  44  has a plurality of shaped recessed areas  46  in which the elements  38  are retracted to create the central opening into which one of the pins  10  can be inserted. Rotation of the surface  44  causes the elements  38  to ride out of the areas  46  and be driven radially inward to indent the pin section  14 . Spring elements (not shown) well known in the art may be used to forcefully retract the elements  38 . 
   The actuator  42  has an offset arm  48  extending away from the opening  40 . At a distal end of the arm  48  there is a bore  50  for receiving an axle  52 . A roller or cam follower (not shown) is mounted on the axle  52  and positioned to ride in curved slot  54  in sliding plate  56 . Plate  56  moves in a direction transverse to base plate  32 . When plate  56  is pushed upward or away from base plate  32 , the roller attached to arm  48  rides in slot  54  moving from left to right as shown in  FIG. 3  thereby causing actuator  42  to rotate counterclockwise. Rotation of actuator  42  causes the camming surface  44  to drive elements  38  radially inward to effect the indenting function. The elements  38  are released by pulling the plate  56  downward toward base plate  32 . 
   It will be appreciated that elements  38  do not rotate about opening  40  but are held fixed in orientation within tool head  30 . The elements  38  are coupled to tool head  30  by a round support bracket  58  which fits into opening  40 . The bracket  58  is a mirror image of support bracket  60 . Each bracket  58 ,  60  had a plurality of radially extending slots  62 . The elements  38  are seated in slots  62  of bracket  58  and the elements  24 ,  26  of indenter  22  are seated in slots  62  of bracket  60 . When tool head  30  is assembled, bracket  60  overlays and is aligned with bracket  58  so that screws (not shown) may be inserted through aligned screw holes  64  in brackets  58 , 60  and threadedly engaged with mating holes in housing section  36  to thereby fix the position of the indenters  20 , 22  with respect to tool head  30 . 
   The indenter  22  is also formed as a combination of the indenter elements  24 , 26  and a cam surface  66 . The surface  66  is a radially inner surface of an opening  68  in a generally circular actuator  70  with distal ends of the elements  24 , 26  in sliding engagement with the cam surface  66 . The elements  24 , 26 , seated in bracket  60  fit into opening  68  in the same manner as described for indenter  20 . When assembled, the actuator  70  is bolted to actuator  42  and rotates concurrently. Bolts (not shown) threadedly couple actuators  42  and  70  via bores  72 . 
   A cover plate  74  fits onto and protects the operating elements adjacent base plate  32 . An upper cover  76  has a recessed area (not visible in  FIG. 3 ) to fit over the actuator  70 . Both plate  74  and cover  76  are coupled to housing section  36  by screws (not shown) passing through the variously shown screw holes. A trigger support bracket  78  is also mounted to the housing section  36  for supporting an actuating trigger (not shown) which may be used in conjunction with a pneumatic operated indenter. The pneumatic cylinder  80  attached to base plate  32  may be a bi-directional unit having a piston extending through aperture  34  and attached to plate  56 . Cylinder  80  is a conventional pneumatic actuator as is the locating and attachment of a trigger mechanism to bracket  78 . 
   The indenters of the present invention may also be used in a hand tool in which the cycling of the hand tool is such that crimping of the pin onto the wire is completed prior to the hand tool being completely closed. While this same feature could be used with the pneumatic indenter of  FIG. 3 , it is not believed necessary since the bi-directional ability of the pneumatic cylinder will forcefully reverse the cam actuator  42 . More particularly, the hand tool is designed with a crimping function such that as the handles of the tool are compressed towards each other, the crimping action completes the crimping of the pin onto the wire and the associated insulation and thereafter the indenters are released from the pin prior to the time that the hand tool completes a fully closed cycle. In this manner, the pressure on the indenters in the hand tool against the pin is released prior to full closure of the hand tool thus allowing the crimped wire and pin to be released from the tool. When the pin is removed, the tool can be easily opened. Otherwise, opening the tool with the pin remaining in place requires significant effort to effect a release of the indenters if they are in contact with the pin. This feature is readily implemented by designing the camming surfaces, such as surfaces  44  and  66  of  FIG. 3 , to have a recess that allows the indenting elements to retract as the tool reaches the end of the crimping cycle. 
   Manually operated hand tools are well known in the art and may take the form of the plier type hand tool  82  shown in  FIG. 4 . However, the tool  82  is modified to incorporate two sets of indenters into a single tool so as to form a compound indenter tool. The two sets of indenters are preferably stacked as shown in the embodiment of  FIG. 3  so that concurrent operation is achieved. In this tool, the indenter elements are fixed in position with respect to the non-pivoting handle  84 . The camming elements are connected to the pivotable handle  86  so that pivoting movement of handle  86  with respect to handle  84  effects rotation of the cam surfaces of the camming elements. Various methods of attaching the handles  84  and  86  to each other for such pivoting movement are well known in the art as is the method for coupling the camming elements to the pivoting handle  86 . Methods of effecting retraction of indenter elements such as elements  38 , 24 , 26  are also well known in the art. However,  FIGS. 5 and 6  are provided to show the motion of the inventive cam arrangement coupled to the tool  82 .  FIG. 5  comprises the group of  FIGS. 5A–5D  showing selected steps of movement of the indenter  22  for crimping pin  10  to insulation  18  while  FIG. 6  comprises the group of  FIGS. 6A–6D  showing corresponding steps of movement of indenter  20  for crimping pin  10  to wire  16 . The pivotable handle  86  is indicated by line  88  to illustrate the position of the handle during the crimping cycle. 
   In  FIGS. 5A and 6A , the handle  86  is in the fully open position and the indenter elements  38  for the pin to wire crimp and the indenter elements  24 , 26  for the pin to insulation crimp are all shown in the retracted position with respect to pin  10 . As the handle  86  is compressed toward handle  84 , the cam surfaces  44 ,  66  begin to rotate and drive the indenter elements radially inward into contact with the pin as shown in  FIGS. 5B and 6B . In  FIGS. 5C and 6C , the indenter elements have ridden up onto the most radially inward surface  90  of each cam surface and have completed the crimp of the pin  10  onto the wire  16  and insulation  18 . As the handle  84  is compressed further, the cam surface continues to rotate into the position shown in  FIGS. 5D and 6D  such that the indenter elements have followed the cam surface into respective recessed areas  92  so that the indenter elements are retracted from contact with the pin  10 . At this time the wire with the pin  10  crimped thereon may be easily withdrawn from the tool  82  and then the handle  84  released to allow the tool to recycle back to the starting position with the indenter elements retracted into the respective starting recesses  94 . 
   While the invention has been described in what is presently considered to be a preferred embodiment, various modifications will become apparent to those skilled in the art. It is intended therefore that the invention not be limited to the disclosed embodiment but be interpreted within the spirit and scope of the appended claims.