Crimping tool with quick-change crimp head for sealing and electrically crimping electrical contacts to insulated wire

A crimping tool with a quick-change crimp head for sealing and electrically crimping electrical contacts to insulated wires. The crimping tool includes a base unit with a receptacle that is configured to actuate and removably and replaceably receive the quick-change crimp head. A crimping die holder body includes a plurality of crimp-seal and continuity-crimping dies. These dies are mounted for movement in the crimping die holder body between an open configuration and a fully crimped configuration. The crimp-seal dies have arcuate die faces that define a substantially closed generally cylindrical form when the dies are in the fully crimped configuration. Actuators are mounted in the base unit. The actuators are adapted to cause the dies to move in the body. A sensor system is configured to prevent the crimping tool from unintentionally repeating a crimping operation on the electrical contact, and to verify continuity-crimp depth of indentation.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention relates in general to methods and devices for mounting an electrical contact to an insulated multi-strand or single strand wire and, more particularly, embodiments of the present invention relate to improvements in methods and devices for mounting contacts onto insulated multi-strand and single strand wires by indenting the contact into the multi-strand or solid wire to form an electrical contact, and crimping the contact around the insulation to form an hermetic seal between the insulation and the contact in one crimping cycle.

2. Description of the Prior Art

Multi-strand and single strand aluminum alloy wires have been widely used for various electrical wiring purposes, and recently in aircraft and aerospace applications where a reduction in the weight of the wiring is achieved by such use. Solid or multi-strand aluminum wires typically include a core of aluminum alloy metal strand(s) surrounded by a coating of flexible electrical insulation material. Aluminum and its alloys, for example, are typically susceptible to corrosion if the coating of insulation is broken. The insulation is always broken when the wires are cut to allow joinder to various fittings and contacts. The multi-strand and solid wire core projects beyond the cut insulation to permit direct electrically conductive connection with the contact. Such contacts typically are in the form of a pin that is adapted to plug into a socket to complete a desired circuit. It has been recognized that the connections between wires, particularly aluminum wires, and contacts should be made in such a way that the cut end of the coating is hermetically sealed to the electrical contact. This prevents moisture from entering the cut end and causing corrosion of the metal core. To this end, electric contacts for multi-strand and solid core electrical wires are typically designed so that a dual crimping action is required to mount them. One crimping action seals the contact to the coating of insulation, and another crimping action (indenting) forms the electrical connection between the metal core and the contact. Tools to accomplish this dual crimping action, particularly hand tools, had been previously proposed. See, for example, Kelly et al. US 2004/0072378, Pub. Apr. 15, 2004. Dual crimping of multi-strand electrical wires where hermetic sealing is not expected had been proposed. See, for example, Klemmer et al. U.S. Pat. No. 5,415,015, and Ohsumi et al. U.S. Pat. No. 6,782,608. Previous expedients were generally less than completely satisfactory because the crimp formed seals between the coating and the contact often failed. Also, the previous crimping equipment was generally time consuming to work with because it was difficult and time consuming to change crimping dies to accommodate different gauges of wire, crimper tool malfunctions, or the like. Such previous equipment was generally incapable of accommodating a full range of wire gauges with one tool. “Single wire gauge” crimp tools of various designs had been proposed. See, for example, Fischer U.S. Pat. No. 3,713,322 (four radially opposed dies actuated by a rotatable cam for crimping a contact to a multi-strand wire).

Those concerned with these problems recognize the need for an improved dual crimping tool.

BRIEF SUMMARY OF THE INVENTION

The present invention has been developed in response to the current state of the art, and in particular, in response to these and other problems and needs that have not been fully or completely solved by currently available crimping tools. Thus, it is an overall object of the present invention to effectively resolve at least the problems and shortcomings identified herein. In particular, it is an object of the present invention to provide a crimper tool wherein a crimping die holder is configured for quick and easy insertion and removal in a base unit. It is also an object of the present invention to provide a crimper tool that crimp forms a reliable hermetic seal between a contact and the insulative coating on a single or multi-strand core wire. It is a further object of the present invention to provide a crimper tool with an adjustable crimp depth. It is a further object of the present invention to provide a crimper tool with a sensor system that prevents the performance of a second crimping action on the same contact-wire assembly. Finally, it is an object of the present invention to provide a crimper tool wherein a crimping die holder is configured for quick and easy insertion and removal from a base unit, a sensor system prevents unintentionally performing two crimping cycles on the same contact and monitors the depth of the electrical crimp, and the crimping operation forms a substantially cylindrical hermetic crimp seal between a contact and the insulative coating on a single or multi-strand core wire. Embodiments of the present invention are particularly suitable for use in attaching contacts to single or multi-strand aluminum wire.

A preferred embodiment of the quick disconnect assembly according to the present invention comprises a bench mounted or hand-held crimping tool. A quick-change crimp head crimps a contact to a single or multi-strand core aluminum alloy wire to form both a reliable hermetic seal and good electrical continuity between the contact and the wire. The quick-change crimp head preferably slips axially in and out of a receptacle in a base unit. Between crimp cycles, the quick-change crimp head is generally held in the receptacle by the action of a latching or locking mechanism. The actuating mechanism for the quick-change crimp head is preferably located in the base unit. This placement of the actuating mechanism minimizes the mass, expense, and complexity of the quick-change crimp head. It also allows for very robust and flexible actuating mechanisms that are capable of accurately accommodating a wide range of wire gauges from, for example, 26 gauge or smaller to 12 gauge or larger. Typically, a separate quick-change crimp head is kept available for at least each wire gauge, and, if required, for each style of contact. When a particular wire gauge or contact style is to be crimped, the proper quick-change crimp head is selected and inserted into the receptacle. The mounting of a quick-change crimp head in a base unit by an experienced operator generally requires less than approximately a minute, and preferably, less than approximately 30 seconds. The actuating mechanism engages the quick-change crimp head when it is properly positioned in the receptacle portion of the base unit. A sensor system prevents accidentally applying two crimping cycles to the same contact-wire assembly and verifies continuity-crimp quality. Such sensor systems are conventional in the crimping art. The accidental application of more than one crimping cycle is conveniently prevented by requiring that the system be reset before it will perform another cycle. Crimp continuity is conveniently assured by providing a signal (audible, visual, tactile, or otherwise) to alert the operator if the contact is not indented to a predetermined depth during the cycle.

In an additional preferred embodiment, a base unit for an insulated single or multi-strand aluminum alloy wire crimping system includes a receptacle into which a quick-change crimp head may be slipped and locked. The crimp head includes a set of crimp-seal dies axially spaced from a set of continuity-crimping dies with both sets being mounted in a crimping die holder body. Both sets of dies perform crimping operations on the same contact-wire assembly. The crimp seal dies form the contact into a substantially smooth unbroken generally cylindrical wall hermetically sealed to the outside of the insulation on the core of the wire. The continuity-crimping dies crimp a wall of the contact into electrical contact with the core of the wire by indenting the wall into the wire. The dies are generally driven by ring cams. The ring cams have internal cam profiles, which engage cam followers that are associated with the respective dies. The contact is received in the die holder body in a contact holder. The contact holder is preferably quickly changeable. Preferably, the tool includes a sensor system. The sensor system prevents the crimping tool from unintentionally performing two crimping operations on the same contact-wire assembly, and detects non-compliant continuity-crimping.

The components of the quick-change crimp head typically include, for example, a die holder body in which several individual dies are mounted for reciprocal axial movement, one or more cam surfaces, typically, internal annular cam surfaces, and a contact holder. The contact holder, dies and ring cam(s) are removable and replaceable in the die holder body. Typically, the die holder body is non-rotatably mounted in the base unit and the actuating mechanism rotates the ring cam(s) to drive the dies into crimping engagement with the contact-wire assembly.

In a typical operation, a predetermined length of the end of a single or multi-strand core wire is stripped of its insulation. This stripping is performed in a separate preliminary operation. A contact is selected. Typically, the contact has an open end, and is otherwise completely closed. The exposed end of the core is inserted into the open end of the contact to such a depth that the insulation is located within the open end of the contact, and the exposed core is in a position to be crimped into conductive engagement with the contact. The contact with the wire so positioned within it is inserted into the contact holder in the quick-change crimp head. Sensors detect when the contact is properly positioned in the contact holder, and arm the system for one crimping cycle. The operator initiates the cycle. During the cycle the actuating mechanism rotates the cam ring(s) to cause linear motion of the associated dies in a predetermined sequence into crimping engagement with the contact. The walls of the contact are indented into conductive engagement with the bare wire core. The walls at the open end of the contact are formed into a generally unbroken cylinder clamped in a hermetic seal around a short length of the outside of the insulation. Preferably, a sensor associated with the actuating mechanical linkage detects the position of a particular moving element in the linkage at the end of the crimping stroke, and from this position the depth of the indentation is deduced. The contact wall must be indented to a predetermined depth to assure the desired electrical conductivity through the crimp.

When a crimp sensor detects that the proper depth of electrical crimp indentation has been reached, the actuating mechanism counter-rotates the cam ring(s) to allow the dies to withdraw from crimping engagement with the contact-wire assembly. This completes the cycle. The sensor prevents a second cycle from being inadvertently initiated until the system is armed again. The crimped contact-wire assembly is withdrawn from the contact holder. The sensor will rearm the system for another cycle when it senses a contact in the proper position in the contact holder.

To acquaint persons skilled in the pertinent arts most closely related to the present invention, a preferred embodiment of a crimping tool that illustrates a best mode now contemplated for putting the invention into practice is described herein by, and with reference to, the annexed drawings that form a part of the specification. The exemplary crimping tool is described in detail without attempting to show all of the various forms and modifications in which the invention might be embodied. As such, the embodiments shown and described herein are illustrative, and as will become apparent to those skilled in the arts, can be modified in numerous ways within the scope and spirit of the invention, the invention being measured by the appended claims and not by the details of the specification or drawings.

Other objects, advantages, and novel features of the present invention will become more fully apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings, or may be learned by the practice of the invention as set forth herein.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring now to the drawings wherein like reference numerals designate identical or corresponding parts throughout the several views. It is to be understood that the drawings are diagrammatic and schematic representations of various embodiments of the invention, and are not to be construed as limiting the invention in any way. The use of words and phrases herein with reference to specific embodiments is not intended to limit the meanings of such words and phrases to those specific embodiments. Words and phrases herein are intended to have their ordinary meanings, unless a specific definition is set forth at length herein.

For purposes of illustration, a bench mounted embodiment of the invention has been shown. It will be understood by those skilled in the art that hand held embodiments of the present invention may be used for lighter gauges, for example, smaller than approximately 18 gauge. For heavier gauges, for example, 14 gauge and heavier, it preferable to use a bench mounted embodiment. The force required to crimp, for example, a 12 gauge wire, generally requires driving motors and linkages that are too large and/or heavy to be mounted in a hand held device. A bench mounted unit is more versatile in that it can crimp all gauges from the lightest to the heaviest, whereas a hand held embodiment is generally limited to the lighter gauges.

Referring particularly to the drawings, there is illustrated generally at10, a base unit with a receptacle in which a quick-change crimp head12is mounted. The base unit is adapted to rest on a bench or other surface. Base unit10includes crimping stroke adjusting micrometers14and16, and crimp actuating motors18and20. Motors18and20are typically either electrical or pneumatic motors. Particularly for hand held devices, the activating electricity may be supplied by batteries, if desired. Hand held devices may also be pneumatically activated, if desired. Stroke adjusters14and16serve to permit very accurate adjustment of the depth of the crimp. This is particularly useful for example, for making prototypes, for short runs, and in adjusting for wear. Stroke adjusters are not necessarily required or even desirable in mass production operations. A crimping cycle is initiated, for example, by pushing a crimp button24. Crimping cycles may be initiated in other ways, if desired. Actuating motors18and20drive the crimping dies. The actuating motors should have sufficient capacity to drive the crimping dies regardless of the gauge of the wire or the nature of the material that is deformed in the crimping operation. For purposes of quality control, and the like, a sensor system is preferably provided. Such sensor systems typically serve to prevent the performance of two crimping operations on the same contact-wire assembly, and detect whether the indenter has traveled the full predetermined length of the indenting stroke. Such sensor systems are conventional in the crimping art, and they are not shown here. If it is desired to override the sensor system and manually reset the system, a reset button15is provided. Axial bore22extends axially through the center of quick-change crimp head12.

With particular reference toFIG. 4, a typical contact26is generally hollow and cylindrical in form, and composed of an electrically conductive material such as, for example, metal. The end28is designed to fit into an electrical socket to complete an electrical circuit. The generally cylindrical wall of the mid-section34is designed to be crimped into electrically conductive engagement with a bare wire core. The hollow contact is open at open end30. The contact wall surrounding the open end30is preferably belled to facilitate the introduction of a wire into the hollow interior of contact26, and to accommodate the insulated coating on the wire. In general, the stripped end of a wire is inserted far enough into contact26to place the end of the insulation within generally frustoconical wall section32. The walls of the contact26are generally malleable enough that the necessary crimping operations may be performed without rupturing them. When open end30is hermetically sealed to a coating of insulation on a wire (not shown), the interior of contact26is sealed against the entry of moisture. Corrosion of the wire core is thus prevented. The electrically conductive characteristics of the contact-wire assembly are thus reliably maintained at predetermined values.

With particular reference toFIGS. 5-9, there is illustrated generally at36, a die holder body for use in quick-change crimp head12. Die holder body36includes a plurality of generally radial bores (die bores) of which48,50and52are typical that intersect with axial bore22.FIG. 6illustrates the positioning of the radial bores when body36is rotated approximately 45 degrees counterclockwise from the position shown inFIG. 5. Die bores50and51are generally radially opposed to one another. There are generally two sets of die bores axially offset from one another. The most axially proximal of the die bores, of which48,50, and51are typical, are adapted to mount radially opposed crimp-seal dies. The most axially distal of the die bores, of which52is typical, are adapted to mount radially opposed continuity-crimping dies. Generally, cylindrical external surface60is adapted to slip axially of longitudinal axis102into a receptacle in base unit10to removably and replaceably mount quick-change crimp head12in base unit10.

There is indicated generally at38(FIGS. 5 and 7) a continuity-crimping cam. Cam3.8has a generally annular flat radially extending face that is adapted to bear slidably against the generally flat annular radially extending ring surface58of body36. A continuity-crimping cam actuator is indicated generally at40(FIGS. 5,10,24and27). Actuator40is adapted to encircle cam38. Actuator40and cam38are keyed together by keys62and64received in mating keyways in actuator40and cam38. Actuator40and cam38are thus rotatably locked together, but are separable by axial movement relative to one another. Lever arm82(FIGS. 5 and 10) projects generally tangentially from actuator40. Movement of lever arm82causes actuator40and cam38to rotate around longitudinal axis102. The nature of the structure is generally such that such rotation is generally through an arc of limited length. Cam38is formed with several lands that project axially for different axial lengths so as to present axially facing surfaces68,70,72,74, and76. These axially facing surfaces generally face towards the proximal end of the quick-change crimp head12. The sides of the lands, of which112is typical, generally extend parallel to the longitudinal axis102.

A crimp-seal cam is indicated generally at42(FIGS. 5 and 8), and an associated crimp-seal cam actuator is indicated generally at44(FIGS. 5 and 10). Cam42is nested within actuator44for rotation therewith by means of the engagement of keys92and106in mating keyways in Cam42and actuator44. Keyway84in cam42is typical of such mating keyways. Cam42includes several lands of different axial lengths. These lands terminate in generally axial facing surfaces86,88,108,110,114,116, and118. These surfaces generally face the distal end of quick-change crimp head12.

The actuators40and44are preferably mounted so that when actuated, they cause cams38and42to counter-rotate relative to one another. Preferably, cam38is rotated first to cause the electrical continuity crimping action and the first phase of the crimp sealing operation to be performed. Cam38is held in the rotated position and cam42is then rotated to cause the performance of the second phase of the crimp sealing operation. Mounting the actuators in the base unit allows the actuators themselves and the drivers for them to be very robust. If, by reason of the use of large sizes or materials that strongly resist deformation, or for any other reason, substantial force is required to perform a crimping operation, that substantial force is available without modification of the base unit. The appropriate quick-change crimp die is inserted into the receptacle, and the equipment is ready for use.

A handle indicated generally at46includes a generally cylindrical proximally projecting wall96, which permits an operator to grasp the quick-change crimp head12for easy removal and insertion into a receptacle in base unit10. Axial bore94of handle46slips over generally cylindrical surface56of body36. Threaded radially extending holes of which98and104are typical serve to threadably mount set screws (not shown). These set screws bear against surface56to securely but releasably mount handle46to body36with cams38and42, and actuators40and44trapped between surface58and radially extending face100of handle46.

In the assembled configuration, cams38and42are rotatably journaled on generally cylindrical surface54of body36. Generally cylindrical internal surfaces132and134of cam38, and generally cylindrical internal surfaces140and142of cam42are rotatably journaled on generally cylindrical external surface54of body36. The lands of the respective cams are interengaged so that adjacent axially facing surfaces of cams38and42are in generally slidable engagement with one another. For example, face116of cam42slidably engages face76of cam38, and face110of cam42slidably engages face72of cam38. Surface90of cam42slidably engages face100of handle46. The lands of the respective cams are of such an arcuate extent that they permit the respective cams to rotate relative to one another without interference through a short arc that is sufficient for crimping purposes. During a crimping cycle, the cams oscillate about the longitudinal axis102between open and crimped configurations.

Actuators40and44are preferably mounted in base unit10, and the connecting keys, for example,62and92, are preferably mounted in the respective actuators. Thus, a quick change crimp head12preferably comprises body36with selected crimp dies mounted in associated die bores, for example,48,50, and52, and cams38and42, all held in the assembled configuration by handle46. Rectangular cut-out66in the outer perimeter of cam38is proportioned to permit it to slid unobstructed past key92in actuator44as the head12is removed and inserted axially into the receptacle in base unit10.

The internal surfaces of cams38and42are shaped to provide cam surfaces. Cam38includes six cam surfaces, four of which (122,126and120,124) are positioned to camingly engage four radially opposed continuity-crimping dies. The remaining two cam surfaces (128,130) are positioned to camingly engage two of four radially opposed crimp-seal dies. The internal surface of cam42includes two cam surfaces (136-138). The two cam surfaces (136-138) in cam42are adapted to camingly engage the two remaining radially opposed crimp-seal dies. The cam surfaces128-130are formed in an axially projecting face of the most proximally extending lands of cam38and project to surfaces70and72, and cam surfaces136-138are similarly formed in an axially projecting face of the most distally extending lands of cam42and extend to surfaces88and86, respectively. By so positioning these cam surfaces in the faces of these axially overlapping lands, these cam surfaces are positioned to drive radially opposed crimp-seal dies that are mounted in radially opposed die bores in body36. The axially inter-extending lands on the respective cams accommodate the axial offset between the crimp-seal and continuity-crimping die bores. Six of the dies, two of which are axially offset from the others, are actuated by one cam. The inter-extending lands permit the axially offset dies to be actuated by this one cam. The cam profiles determine the strokes of the dies.

With particular reference toFIGS. 10-14, the relationships between the cams, the actuators, the crimping die holder body, and the crimping dies is schematically illustrated. InFIG. 10the arms of the actuators and the engagement of the keys in the respective keyways is illustrated. InFIG. 11the arms of the actuators are not shown so as to permit clearer schematic illustration of the relationships between the remainder of the structure. InFIG. 12the relationships of the cam surfaces, the dies and the contact26are schematically illustrated. InFIG. 13, just two of the crimp-seal dies and the associated cam surface are illustrated. InFIG. 14, the two crimp-seal dies ofFIG. 13are shown in a crimping configuration with part of the associated crimping die holder body and cam surface.

The movement of actuator40through a short arc to the position shown at144(FIG. 10) causes the wall of a contact and the multi-strand or solid core or the like of a wire to be fully crimped together. Such crimping typically involves indenting the wall of the contact into the single or multi-strand wire. The wall of the contact exhibits little or no resilience so the indentation remains when the crimp forming dies are withdrawn. Reliable and repeatable electrical continuity is thus provided for each contact-wire assembly that is subjected to such a crimping operation. In the embodiment chosen for purposes of illustrating the invention, this movement also performs the first stage of making a crimp-seal. Likewise, the movement of actuator44to the position shown at146causes the completion of a crimp-seal between a contact and the coating of insulation on a wire. The seal here serves to exclude moisture vapor from contact with the exposed bare end of wire. Because it excludes moisture, this crimp-seal is described as a hermetic seal.

The respective crimp forming dies are driven reciprocally in the crimping die holder body36by the interaction between cam followers, of which148,152,156, and160are typical. Cam follower148is mounted to die shaft150. Similarly, cam followers152,156, and160are mounted to die shafts154,158, and162, respectively. Die shafts164,166,168, and170are likewise provided with associated cam followers. The length of the stroke through which the die shafts travel during a crimping operation is determined by the profile of the cam surface and the length of the arc through which the associated actuator travels during the crimping cycle. The length of the respective cycle arcs is conveniently adjusted for each actuator by, for example, adjusters14and16, respectively.

In the embodiment chosen for illustration, the cam followers and die shafts are all one piece. This is not a required configuration. The cam followers and die shafts may be separate from one another, if desired, so long as they interact to accomplish the crimping operations.

When actuator40is moved arcuately to position144, the engagement of keys62and64with the continuity-crimping cam38cause it to rotate clockwise about axis102to drive, for example, cam surface120over cam follower152. This causes die shaft154to move radially towards contact26. The clockwise rotation of cam38also causes, for example, cam surface130to camingly engage cam follower156, which in turn drives die shaft158radially towards contact26. The counterclockwise rotation of actuator44to position146causes crimp-seal cam42, acting through cam surfaces138and136and associated cam followers148and172, respectively, to camingly actuate die shafts150and164, respectively. The actuator44acts on cam42through the inter-engagement of keys92and106. The crimp-seal die faces of die heads198and196are generally cylindrically concave. The counterclockwise rotation of the cam that actuates them forces these faces to the fully crimped configuration shown, for example, inFIG. 14. InFIG. 14the contact26is shown in its uncrimped form with the die heads198and196superimposed. This visual comparison of the uncrimped contact with the fully actuated dies makes apparent the degree of deformation that occurs as a result of the crimping operation.

With particular reference toFIG. 15, where the continuity-crimping dies are shown fully retracted, andFIG. 16, where the dies are shown fully extended, the positions of the die heads188,192,194, and190are shown relative to the contact26. In the fully retracted position ofFIG. 15, the contact26may be freely removed and inserted. In the fully crimped position shown inFIG. 16, the depth of the indentation formed during crimping relative to the uncrimped contact26is apparent. The dies reciprocate between these two positions during a crimping cycle. The cycle starts with the dies in the position ofFIG. 15, move through the position ofFIG. 16, and back to the position ofFIG. 15at the end of the cycle.

With particular reference toFIG. 17, where the positions of the crimp-seal dies at the end of the first half of a crimp cycle are shown, andFIG. 18, where the dies are shown in the fully closed or crimped configuration, the positions of the die heads relative to the contact26are shown. The contact26is shown in the uncrimped form in both Figs so as to illustrate the degree of deformation of the contact that takes place. The crimp-seal die faces on the crimping ends of die shafts158and168are actuated by cam38in the first half of the crimp-seal forming operation. These faces have both flat and arcuate areas. These compound faces perform two functions. The flat areas serve to closely and slidably engage the sides of crimp-seal die heads196and198, and the generally concave cylindrical areas in portions200and202serve to form a generally cylindrical crimp. These flat areas on the sides of die heads196and198slidably engage the mating flat areas on the compound ends of the opposed die heads so that there is substantially no space between them. Thus, when they fully close together, as shown inFIG. 18, there is no room for the metal of the contact to extrude between them. The arcuate surfaces at the ends of the crimp-seal die heads form a substantially unbroken cylinder204in the fully crimped configuration. This substantially closed generally cylindrical form prevents the formation of channels in the crimped contact through which moisture might migrate. This is important in achieving an hermetic seal. During the crimping operation, the metal of the contact26is caused to shrink around the coating of insulation to form a smooth unbroken cylinder. If desired the crimp-seal could be given a slightly-tapered form, for example, a smooth unbroken somewhat frustoconical form. As used herein, “generally cylindrical” as applied to the form of the crimp-seal and crimp-seal forming dies is intended to include slightly tapered forms, and forms that include axially extending sections that are straight and axially extending sections that are tapered in the same crimp seal.

In the embodiment chosen for purposes of illustration, the die shafts are received for reciprocal sliding motion in cylindrical bores of which50and51(FIG. 14) are typical. For purposes of withdrawing the die after a crimping operation is performed, a compression coil spring, of which186is typical, is provided. Spring186is located in annular spring pocket182. Spring pocket182generally shares a common longitudinal axis with bores51and50. Spring186bears in compression against the underside of cam follower148. Cam follower148is forced to move radially inwardly by engagement with surface138during a crimping operation. As cam surface138is rotated clockwise during the withdrawal phase of a crimping cycle, spring186forces cam follower148to follow cam surface138. The cam followers, of which148is typical, are received in generally rectangular pockets, of which180is typical. The rectangular nature of the pocket180prevents the die from rotating about the longitudinal axis of the die shaft so as to misalign the die face.

With particular reference toFIGS. 19-22, the profile of cam38is shown with the associated dies. InFIG. 19the profile of cam38is shown in the fully retracted position that is typical of the start and end of a crimp cycle. InFIG. 20the profile of cam38is shown rotated to the position it typically occupies when the dies are fully extended half way through a crimping cycle. The cam followers156and206have moved along cam surfaces130and128, respectively, to accomplish the first half of a crimping operation. Only the crimp-seal dies are illustrated inFIGS. 19 and 20. InFIG. 21the continuity-crimping dies are shown with the profile of cam38at the fully retracted position. Rotation of the cam profile to the position shown inFIG. 20causes the cam followers152,160,210, and208to move along the associated cam surfaces to perform a continuity-crimping operation.

With particular reference toFIG. 22, the radially opposed axial ends of crimp-seal die heads196and198present concave, generally cylindrical die faces220and222, respectively. Flat portions200and202at the ends of generally cylindrical die shafts168and158, respectively, present radially opposed generally cylindrical die faces218and216, respectively. These four die faces (216,218,220,222), when both cams are in the fully extended configuration, as shown inFIG. 22, define a substantially closed generally cylindrical configuration that forms a contact into a smooth unbroken crimp-seal with the insulation on a wire. The contact is prevented from extruding into the axially extending spaces between the generally cylindrical die faces by providing a close sliding fit between the planar portions (of which212is typical) of the die faces of compound crimp-seal die shafts158and168with the mating planar sides (of which214is typical) of die heads196and198.

With particular reference toFIG. 23, in this cross-sectional view of die holder body36by itself, radially opposed die bores50and51share substantially the same longitudinal axis and are shown intersecting axial bore22. Die bore80extends in substantially the same plane as die bores50and51, but substantially normal thereto. Generally rectangular pocket234serves the same function as pocket180, that is it serves to maintain the die face of a die in proper alignment. The die bores (of which236is typical) that are axially offset from die bores50,51, and80also intersect axial bore22. The cylindrical wall224and the frustoconical wall226tend to help guide contact-wire assemblies towards axial bore22. Crimping operations are performed in bore22. The counter bores238and240provide convenient mounting locations for sensor related equipment (not shown) and the contact holder.

FIGS. 24 through 27illustrate the adjustment of the length of the crimping stroke by means of adjusting the length of the crimping arc through which the actuators40and44drive cams38and42. Stroke limiters244and250are adjustably mounted to micrometer adjusters14and16, respectively. Actuators40and44are mounted to actuator drivers248and242, respectively. Actuator drivers242and248drive the respective actuators through an arc, the length of which is controlled by the width of gaps246and252. Precise adjustment of stroke limiters244and250defines the widths of gaps246and252, respectively. Widening gap252, for example, lengthens the stroke of the continuity-crimping dies and the two crimp-seal dies that are activated by cam38. Widening gap246lengthens the stroke of the two crimp-seal dies that are associated with cam42. Fixed stroke limiters that are not adjustable best serve some applications. The stroke limiters, for example, may take the form of solid stops or limiter switches that deactivate the devices (motors or the like) that are actuating the actuating drivers242and248.

FIGS. 28-31illustrate typical crimp-seal dies that are actuated by cam38.FIGS. 32-35illustrate the continuity-crimping dies that are actuated by cam38.FIGS. 36-38illustrate the crimp-seal dies that are actuated by cam42. The cam followers, of which156,152, and148are typical, all have generally rectangular plan forms, see for example,FIGS. 29,33, and37. The corresponding pockets in the die holder body36have generally the same plan forms. This is necessary to maintain the alignment of crimping faces216,230, and222with the contact. In general, the crimping faces are aligned parallel to the longitudinal axis102of the system. The flat faces202(FIGS. 29-31) and260(FIGS. 36-37) are provided so that there is no undesired or asymmetrical distortion of a contact at the axial end of the crimp-seal dies. The crimping faces230of the continuity-crimping dies are preferably configured with two axially aligned indenters,256and258, so as to provide two electrical contacts between a contact26and an associated wire core. This insures reliable electrical continuity.

FIG. 39illustrates by way of a see through schematic the relative positions of the respective dies and contact26at the beginning of a crimping cycle. All of the dies shown inFIG. 39are crimpingly driven by cam38. Preferably, although not necessarily, cam38is activated first and proceeds through at least a part of the crimp forming phase before the other two crimp-seal forming dies are activated by cam42.

FIG. 40is a broken cross-sectional view of a die holder body with the end28of a contact26mounted in a close fit in socket271(FIG. 41) of a contact holder in position for a crimping operation. The continuity-crimping dies are shown superimposed over an uncrimped contact to illustrate generally the degree of deformation that these dies cause in the crimping operation. The socket end of the die holder is mounted in bore22. The other end269of the die holder is mounted in the axial bore of a quick detach fitting268. A mounting ring266is held in position in the die holder body by screws, of which276is typical. Screw276is threadably engaged with the die holder body by means of threaded bore279. Quick detach fitting268is releasably attached to mounting ring266by means of radially extending pins280. Radially opposed notches (not shown) are formed in mounting ring266so as to permit pins280to pass axially therethrough. A quarter to half a revolution of fitting268engages pins280with the underside of mounting ring266where it is held by the force of compression spring272. The remote end275of the axial bore in fitting268is plugged with a vacuum line fitting274. A compression spring272extends in the axial bore of the fitting268between the enlarged end270of the contact holder and the vacuum line fitting274. Compression spring272serves to hold the contact holder in bore22, and fitting268in engagement with mounting ring266. The axial bore of quick detach fitting268is stepped so that the enlarged end270of the contact holder engages the step in the axial bore of fitting268. The contact holder has an axial bore264that extends therethrough. Vacuum line fitting274has an axial bore278extending therethrough. The shoulder262of contact26engages and substantially seals the end of socket271. If vacuum fitting274is attached to a vacuum line (not shown) and a vacuum is drawn. The vacuum line is substantially open to atmospheric pressure until a contact is fully. inserted into socket271. The pressure will drop when a contact26is fully seated in socket271with shoulder262seated against the open end of socket271. The pressure will rise as soon as the contact is withdrawn. Pressure sensors such as transducers (not shown) or the like may sense these pressure changes. These sensors are configured to generate a first signal when the pressure drops and a second signal when the pressure rises. Preferably, the system is configured so as to allow a crimping operation to be performed only when the removal and insertion of a contact is sensed, unless the system is overridden by the activation of manual reset button15. This prevents the inadvertent performance of a second crimping action on the same contact-wire assembly. In the embodiment chosen for illustration, a sensor system based on a vacuum has been described. Vacuum based sensor systems had been previously used in contact crimping operations of various kinds, but not in crimping systems of the kind described and claimed herein. Other sensor systems that are not based on breaking or establishing a vacuum may be employed, if desired. Electrical, optical, pneumatic, mechanical, combinations thereof, or the like, sensors may be utilized in both the bench mounted and hand held embodiments of the present invention. The vacuum also serves to hold the contact in the socket271in position to be crimped.

The contact holder may be easily and quickly (generally less than one minute by a skilled operator) removed and replaced. Fitting268is rotated to align pins280with the release slots (not shown) in mounting ring266and is axially withdrawn from engagement with the die holder body. Fitting268carries the contact holder with it. Fitting274and spring272are removed from bore275and the contact hold is removed. A new contact holder is inserted and the disassembly process is repeated in reverse. The crimp head may thus be quickly reconfigured for a different contact. Where different dies are necessary, a second quick-change crimp head is preferably provided. Changing out a set of dies generally requires more time and skill than is available in a mass production environment. Such a die change out can be accomplished by skilled workers in a few minutes (generally less than 10 minutes).

The quick-change crimp head is axially slidably mounted in a receptacle in the base unit. This head is preferably held there by a special locking mechanism (not shown), so it may be removed and replaced very quickly (generally less than one minute by a skilled operator). Even if some quick release fastener is used to hold the crimp head in place, the total time to change out a crimp head is generally less than two minutes. The use of a common base unit10for use with a plurality of quickly changeable and configurable crimp heads provides the capacity for the efficient performance of a wide variety of crimp forming operations in a mass production environment.

FIG. 42depicts the operation of the sensor system from the insertion of the electrical contact into a contact holder in a crimping tool through the crimping cycle.

What has been described are preferred embodiments in which modifications and changes may be made without departing from the spirit and scope of the accompanying claims. Many modifications and variations of the present invention are possible in light of the above teachings. It is therefore to be understood that, within the scope of the appended claims, the invention may be practiced otherwise than as specifically described.