Unitary connector pin formed by two-stage cold heading die

A unitary metal connector pin formed by a cold heading die has a body with a disc-like expanded portion on a first end thereof which is adapted to engage and retain a first body when the pin is inserted through a first aperture in the first body. On a second, opposed end of the pin are disposed plural spaced flexible fingers each having a respective outwardly projecting, radially expanded portion. The radially expanded portions form a segmented outer ring on the pin capable of first undergoing inward deflection, followed by outward radial expansion for engaging a second body when the fingered end of the pin is inserted through a second aperture in the second body for securely coupling the two bodies together. The cold heading die includes a first stage for forming in a connector pin blank a first hollowed-out end portion with the flexible fingers and a second stage for forming the second radially expanded end portion and the outer projections on the flexible fingers.

FIELD OF THE INVENTION

This invention relates generally to pin-like metal connectors for securely coupling two bodies together in a releasable manner, as well as to apparatus and a method for making this type of connector. More specifically, this invention is directed to a unitary connecting pin adapted for insertion through aligned apertures in first and second bodies to securely connect the two bodies together in a releasable manner, and is further directed to a two-stage cold heading die arrangement for making the inventive metal connecting pins.

BACKGROUND OF THE INVENTION

Push-type fasteners are commonly used to fasten together a pair of bodies, or parts, wherein the fastener is inserted through aligned apertures in the two bodies. This type of fastener typically includes a moveable expansion member which engages one of the bodies through which the connector is inserted by means of outward radial movement. The fastener also typically includes a second expanded member adapted for securely engaging the other body. These types of connectors typically involve a “push to latch” action for coupling the two bodies, and a “pull to unlatch” for disconnecting and separating the two bodies. The engaging element is typically in the form of a spherical ball which is biased outwardly such as by means of a spring to expand the radial dimension of the connector and prevent its withdrawal from the aligned apertures in the two connected bodies. These types of connectors also frequently include a control sleeve, or outer slider, adapted for linear displacement along the length of the connector for urging the outwardly biased ball inwardly and out of engagement with one of the connected bodies, permitting the pin to be withdrawn from the bodies which can then be separated. Examples of these types of push-pull connectors can be found in U.S. Pat. No. 5,562,375 to Jackson; U.S. Pat. No. 7,225,709 to Liao; and U.S. Pat. No. 6,206,432 to Kamiyama. The last patent contemplates forming the connector by deep drawing of a sheet metal.

The above described push-pull connectors are characterized as including various components, some of which are movable and thus require assembly, increasing the complexity and cost of the connector. The use of non-integral moving parts also increases the likelihood of component failure and limits the useful lifetime of the connector. In addition, contact between one moveable component with one or more other components limits the types of environments in which these types connectors are capable of extended use.

The present invention addresses these limitations of prior art push-pull types of connectors by providing a one piece, or unitary, connector pin comprised of a hard, durable metal and adapted for manufacture using a single cold heading die.

OBJECTS AND SUMMARY OF THE INVENTION

Accordingly, it is an object of the present invention to provide an improved push-pull type fastener which is easily attached to two thus connected bodies and is easily removed for disconnecting the bodies, is of unitary structure and does not require assembly of parts, is adapted for quick and inexpensive manufacture, and is comprised of high strength metal for secure coupling and long term, repetitive use.

A further object of the present invention is to provide a removable pin-like connector for securely coupling two bodies, parts or components, which includes only one component part and thus requires no assembly prior to use.

A still further object of the present invention is to produce pin-like metal connectors by means of a single, two-stage cold heading die for faster, less expensive, simpler and more reliable manufacture of the connectors.

Yet another object of the present invention is to provide for the manufacture of pin-like frictionally engageable connectors which are comprised of a single, unitary member, the manufacture of which simplifies and reduces the cost of fabrication by using a single cold heading die arrangement, provides for the attachment and detachment of the connecting pin via a single movement using one hand, and forms the individual pins by cutting off the end of metal wire provided to the cold heading die at a high speed feed rate.

The present invention contemplates a two-stage cold heading die for forming a unitary metal connecting pin, the cold heading die comprising a unitary die block having first, second and third linear cylindrical channels extending therethrough, wherein the first and second channels are in parallel, spaced alignment and the third channel intersects the first and second channels and is oriented generally orthogonal to the first and second channels; a first stage including intersecting portions of the first and third channels and adapted to receive and direct a pin blank into the first channel and a second stage adapted to receive the pin blank from the first stage and direct the pin blank into the second channel, the pin blank having a generally cylindrical shape and first and second opposed end portions; first displacement and forming means for engaging the pin blank in the first channel and forming a hollowed out first end portion and plural flexible fingers disposed about an outer periphery of the first end portion of said pin blank, and for positioning the pin blank in alignment with the third channel; displacement means disposed in the third channel and adapted to engage and move the pin blank from alignment with the first channel to alignment with the second channel; and second displacement and forming means disposed in the second channel for engaging the pin blank in said second channel and forming a disc-like, laterally extended base on the pin blank's second end portion, and further forming an outwardly extending upraised portion on each of the flexible fingers and bending distal ends of the fingers radially inwardly to form a tapered portion on the first end portion of the pin blank in forming a connecting pin; wherein the displacement means engages the formed connecting pin and displaces the connecting pin in the third channel to a discharge port in the cold heading die for discharge therefrom.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

Referring toFIG. 1, there is shown in partially cutaway and dotted line form a two-stage cold heading die10in accordance with one aspect of the present invention. Cold heading die10includes a die block12comprised of a hard, high strength metal such as steel having a first stage10aand a second stage10bfor forming a metal article such as a connector pin76as shown in partially assembled form inFIG. 3and in final form inFIG. 4.

Connector pin76is comprised of a high strength metal such as of steel and includes an elongated, linear cylindrical body78. On a first end of cylindrical body78is disposed a disc-like, laterally extended base80. On a second, opposed end of the cylindrical body78there is formed, in a manner described in detail below, a cylindrical, hollowed-out end portion82shown in dotted line form inFIG. 3. Also disposed on the second end of cylindrical body78are plural, spaced peripheral fingers, where three of these peripheral fingers are identified as elements84a,84band84c.In the described embodiment, there are four equally spaced peripheral fingers disposed about the periphery of cylindrical body78, although only three are shown inFIG. 2. Disposed at the base of each of the plural fingers84a,84band84c,as well as at the base of the fourth finger which is not shown inFIG. 3, is a respective peripheral annular extended portion, where the lower annular extended portions of fingers84aand84care respectively identified inFIG. 2as elements86aand86c.The outwardly extended portions of each of each of these fingers provide a segmented, outwardly extending ring adapted for engaging a first body (not shown), while the connector pin's laterally extended base80is adapted for engaging a second body (also not shown) for securely connecting the two bodies after the connector pin has been inserted through a pair of aligned apertures disposed in the two bodies.

Referring back toFIG. 1, the cold heading die's die block12includes first, second and third cylindrical slots14,16and18extending therethrough. The first and second cylindrical slots14,16are shown inFIG. 1as extending vertically through the die block12and are parallel to one another. The third cylindrical slot18is shown extending horizontally through die block12as illustrated inFIG. 1. The third cylindrical slot18intercepts and extends through the first and second cylindrical slots14,16and is aligned orthogonal, or at a right angle, to the first two cylindrical slots. The first and second cylindrical slots14,16include respective upper portions14aand16adisposed above the third cylindrical slot18as shown inFIG. 1, and respective lower portions14band16bdisposed below the third cylindrical slot, with the respective upper and lower portions of the first cylindrical slots arranged in vertical alignment, and the upper and lower portions of the second cylindrical slot disposed in vertical alignment, again as shown inFIG. 1. Disposed within the lower portion14bof the first cylindrical slot14in a sliding manner is a first cylindrical shaft20. Similarly, disposed within the lower portion16bof the second cylindrical slot16in a sliding manner is a second cylindrical shaft22. Similarly, disposed in the upper portion14aof the first cylindrical slot14and in the upper portion16bof the second cylindrical slot16in a sliding manner are third and fourth cylindrical shafts24and26, respectively. The upper and lower portions14a,16aand14b,16bof each of the first and second cylindrical slots14,16extend to the respective upper and lower surfaces of the die block12providing access to all of the first through fourth cylindrical shafts20,22,24and26from outside of the die block. Thus, a lower end of the first cylindrical shaft20is coupled to a first rack and pinion arrangement28to allow for the extension and retraction of the first cylindrical shaft20within the first cylindrical slot14of die block12. Similarly, a lower end of the second cylindrical shaft22is coupled to a second rack and pinion arrangement32for extending and retracting the second cylindrical shaft within the second cylindrical slot16. The first rack and pinion arrangement28includes first and second toothed wheels28aand28badapted to engage and displace a first toothed array30disposed on an outer surface of a lower end portion of the first cylindrical shaft20. Similarly, the second rack and pinion arrangement32comprised of a pair of toothed wheels32aand32bengage a second toothed array34disposed on a lower, outer surface of the second cylindrical shaft22. The second rack and pinion arrangement32allows for the extension and retraction of the second cylindrical shaft22within die block12.

Coupled to an upper end of the third cylindrical shaft24as shown inFIG. 1is a first dual-acting hydraulic cylinder36a.The first hydraulic cylinder36aprovides for the extension and retraction of the third cylindrical shaft24within die block12. The outer surface of fourth cylindrical shaft26is provided with a third toothed array42which is engaged by fifth and sixth toothed wheels46aand46bof a third rack and pinion arrangement46. The third rack and pinion arrangement46allows for the extension and retraction of the fourth cylindrical shaft26within the upper portion16aof the second cylindrical slot16. It should be noted here that while the first, second and fourth cylindrical shafts20,22and26are extended and retracted within die block12by means of a respective rack and pinion arrangement, while the third cylindrical shaft24is extended and retracted by means of a dual-acting hydraulic cylinder36a,any of these cylindrical shafts could be driven by either a dual-acting hydraulic cylinder, a rack and pinion arrangement or an eccentric wheel drive arrangement (described below), as all of these reciprocating, linear drive arrangements are considered equivalent for use in the present invention.

Disposed within the third cylindrical slot18in a sliding manner are first and second displacement members35aand35b.First displacement member35ais coupled to a second hydraulic cylinder36bfor linearly displacing rightward and leftward as shown inFIG. 1the first displacement member within the third cylindrical slot18in die block12. Similarly, the second displacement member35bis coupled to a third hydraulic cylinder36cfor linearly displacing rightward and leftward the second displacement member within die block12. Thus, when the second hydraulic cylinder36bextends, the first displacement member35ais extended further into the die block12in moving to the left as viewed inFIG. 1. Similarly, upon retraction of the second hydraulic cylinder36b,the first displacement member35ais moved to the right as viewed inFIG. 1. Similar extension and retraction of the third hydraulic cylinder36cextends or retracts the second displacement member35bin moving the second displacement member to the left or right within die block12as viewed inFIG. 1. In forming a connector pin in accordance with the present invention, the first, second, third and fourth cylindrical shafts20,22,24and26are displaced upwardly and downwardly and the first and second displacement members35aand35bare moved leftward and rightward in die block12as viewed inFIG. 1by means of a controller66coupled to each of the above described hydraulic cylinders and rack and pinion arrangements. Controller66is a computer-based controller and may be of conventional design and operation, and is programmed to sequentially actuate the first, second and third hydraulic cylinders36a,36band36cand the first, second and third rack and pinion arrangements28,32and46in a precisely controlled, sequential manner in forming a connector pin in accordance with the present invention as described in detail in the following paragraphs.

Referring toFIGS. 11 and 12, there are respectively shown perspective and side elevation views of a connector pin62in accordance with the present invention. Connector pin62includes a generally cylindrical, solid body69having a laterally extending base80on a first end thereof. Disposed on a second, opposed end of the cylindrical body69are plural, spaced, peripheral fingers84a-84d.Disposed between adjacent fingers is a respective linear slot. Thus, linear slot65ais disposed between adjacent fingers84aand84d,while linear slot65bis disposed between adjacent fingers84aand84b.Similarly, linear slot65cis disposed between adjacent fingers84band84c, while linear slot65dis disposed between adjacent flexible fingers84cand84d.The distal end of each of the flexible fingers84a-84cis generally flat, and the flat distal ends of the four flexible fingers define a generally circular opening67disposed in the end of the connector pin62which facilitates inward flexure of the four flexible fingers when inserted through an aperture within the pair of bodies, or objects,70aand70bwhich the connector pin securely connects together as shown inFIG. 13. Disposed on respective outer portions of each of the four flexible fingers84a-84dis a respective peripheral annular extended portion. Thus, the first, second, third and fourth peripheral fingers84a-84drespectively include on an outer portion thereof first through fourth peripheral annular extended portions85a-85das shown in the figures. As shown inFIG. 13, connector pin62is adapted for insertion through aligned respective apertures71aand71bwithin the first and second bodies70aand70b.Before peripheral annular extended portions85a-85con the respective four plural, spaced, peripheral fingers84a-84dare adapted for inward flexure when inserted through a respective aperture within one of the bodies70a,70bto facilitate insertion of the pin through these apertures. When fully inserted through the second body, or first body70aas shown inFIG. 13, the four extended portions85a-85dof the fingers radially expands outwardly so that the four fingers engage the first body70a,while the laterally extended base80engages the second body70bfor securely maintaining the first and second bodies connected together. While four spaced, peripheral fingers84a-84dare shown forming part of connector pin62, the present invention is not limited to this number of peripheral flexible fingers, as the present invention may use virtually any number of flexible members on an end of the connector pin to securely engage one of the coupled bodies when the connector pin is inserted through both of the connected bodies.

Disposed within die block12is a fourth slot60. The fourth slot60is adapted to receive the end of a metal wire54. Engaging the metal wire54is a conventional rotary drive motor56which is illustrated in perspective view inFIG. 6. Rotary drive motor56is preferably a high torque, low speed hydraulic motor having a hydraulic fluid input port108and a hydraulic fluid output port110. Rotary drive motor106further includes a generally flat upper platform112from which extends a rotating drive shaft114. Rotary drive shaft114is adapted for insertion through a center aperture116awithin a rotating disc116. With rotating drive shaft114inserted through the center aperture116aof rotating disc116, the disc is rotationally displaced at low speed and high torque. Disposed about the outer periphery of rotating disc116is an outer recessed channel118which is adapted to frictionally engage metal wire54and displace the metal wire into the fourth slot60within die block12.

Under the influence of rotary drive motor56, metal wire54is introduced into and displaced upward within the fourth slot60until the end of the wire engages an upper portion of third cylindrical slot18at location18a.With the first and second displacement members35a,35brespectively moved by the second and third hydraulic cylinders36band36cto the far right end of third cylindrical slot18with die block12as viewed inFIG. 1, the gap44between the first and second displacement members will be aligned with the upper end of the fourth slot60and will be adapted to receive the end of the metal wire54. The combination of the first and second displacement members35a,35bis then moved leftward as viewed inFIG. 1causing a cutting member72disposed on a lower end portion of the first displacement member to sever the metal wire54forming a metal wire section in the shape of a cylindrical pin62a.As shown inFIG. 2, cutting member72includes a generally semi-circular cutting edge72afor severing metal wire54and a generally circular aperture72bfor attaching it to first displacement member35a. With the metal wire pin62adisposed between the first and second displacement members35a,35b,leftward displacement of the displacement members as viewed inFIG. 1will result in leftward displacement of the metal wire pin. Leftward movement of the displacement members35a,35bby the second and third hydraulic cylinders35b,35cplaces metal wire pin62ain vertical alignment with the first cylindrical slot14. Then, under the control of controller66, the first rack and pinion arrangement28displaces the first cylindrical shaft20upward as viewed inFIG. 1so as to raise the connector pin62ato the position indicated by connector pin62bwithin the upper portion14aof the first cylindrical slot14. Controller66then actuates first hydraulic cylinder36aso as to displace in a downward direction as viewed inFIG. 1, the third cylindrical shaft24so that the lower end of the third cylindrical shaft engages the upper end of the connector pin62band applies sufficient pressure so as to form a cylindrical recess shown inFIG. 3in dotted line form as element82. During this process, the end of the third cylindrical shaft24forms four peripheral, spaced fingers on the upper end of connector pin62b, three of which are shown as elements84a,84band84cinFIG. 3. In a preferred embodiment, four peripheral fingers are formed in the upper end of the connector pin62b,although only three are shown inFIG. 3for simplicity.

Referring toFIG. 5, there is shown an end-on view of the lower end of the third cylindrical shaft24which forms the spaced fingers and cylindrical recessed portion82within an end of the connector pin62a.The lower end of the third cylindrical shaft24includes an outer peripheral circular wall48and an inner cylindrical die member49with an annular space51disposed between the outer circular wall and the inner cylindrical die member. Downward movement of the third cylindrical shaft24with its lower end engaging the upper end of connector pin62acauses the cylindrical die member49to form the cylindrical, hollowed-out end portion82. Four cutting blades53a-53dform the four peripheral, spaced fingers about the outer periphery of the connector pin62a.

Following the formation of the cylindrical, hollowed-out recessed end portion82and the plural fingers84a-84din the upper end of the connector pin62, the first hydraulic cylinder36afurther extends, while the first cylindrical shaft20is lowered by means of the first rack and pinion arrangement28under the control of controller66. The connector pin62bis lowered within the upper portion14aof the first cylindrical slot14until it is within the third cylindrical slot18, whereupon controller66initiates extension of the second hydraulic cylinder36band retraction of the third hydraulic cylinder36cso as to displace the first and second displacement members35a,35bleftward until connector pin62bis aligned with the upper and lower portions16aand16bof the second cylindrical slot16. Then, under the control of controller66, the second cylindrical shaft22is raised by the second rack and pinion arrangement32so as to also raise the connector pin62bwithin the upper portion16aof the second cylindrical slot16. The connector pin62bis raised by the upward movement of the second cylindrical shaft22until it is immediately below a die member58connected to a support shaft44disposed within the upper portion16aof the second cylindrical slot16. Downward actuation of the third rack and pinion46by controller66causes the combination of support shaft44and die member58to move downward so that the die member engages the plural peripheral fingers disposed about the upper end portion of the connector pin62b.

As shown inFIG. 4, contact between the lower tapered surface58aof die member58with the upper peripheral fingers (only two fingers are shown as elements84aand84cfor simplicity) of the connector pin62bcauses inward bending of the plural fingers to form a tapered end on the connector pin. In addition, further downward displacement of tapered die member58in contact with the pin connector's four flexible fingers84a-84dresults in the formation of radially expanded portions on the lower end of each of the four flexible fingers. Two of these radially expanded portions respectively disposed on lower end portions of flexible fingers84aand84care shown as elements85aand85cinFIG. 4. Four spaced recesses are disposed within and about the inner circumference of the upper portion16aof the second cylindrical slot16to accommodate formation of the expanded portions disposed on the inner end portions of the four flexible fingers85a-85d.Simultaneously, upward pressure applied to the lower end of the connector pin62bby means of the upper end of the second cylindrical shaft22causes an outward radial expansion of the lower end of the connector pin to form the pin's laterally extended base80. An annular recess21disposed about the inner surface of the upper portion16aof the second cylindrical slot16accommodates the formation of the connector pin's laterally extended base80.

Referring toFIG. 7, there is shown a sectional view of a portion of a modified die block88for use in the present invention in fabricating connector pins of various lengths. As in the previously described embodiment of die block12, die block88shown inFIG. 7includes an elongated cylindrical slot14corresponding to the first cylindrical slot in the embodiment illustrated inFIG. 1. Disposed within cylindrical slot14is the third cylindrical shaft24as in the previously described embodiment. Also included in die block88are plural outwardly extending recesses on the inner surface of the third cylindrical slot24, where two are shown as elements97aand97cto accommodate radial, outward expansion of the plural, spaced peripheral fingers. Two of these outward expansions of flexible fingers84aand84care identified as elements97aand97cinFIG. 7. Similarly, arrows98aand98bindicate the direction of metal flow in the formation of the laterally extended base80on the lower end of connector pin62as pressure is applied in the direction of arrow102on the connector pin by the second cylindrical shaft22.

Die block88further includes plural die block inserts100a-100dshown in a stacked array inFIG. 7. Each of the die block inserts100a-100dincludes a pair of aligned, threaded slots92aand92brespectively adapted to receive threaded connectors, or bolts,96aand96b.Threaded bolts96aand96bmaintain the plural die block inserts100a-100din a secure, tight-fitting, stacked assembly as shown in the figure. Alignment of the threaded apertures in each of the stacked die block inserts100a-100dis provided by means of a pair of alignment pins94aand94brespectfully inserted in corresponding alignment slots97and99in each of the die block inserts. By removing selected ones of the die block inserts100a-100d,the length of the pin connector formed in the die block88may be precisely controlled. For example, the individual die block inserts100a-100dmay be sized so that the presence of all four die block inserts will provide a connector pin 1 inch in length. Removal of die block insert100dwill provide a connector pin ¾ inch in length. Removal of die block insert100cwill provide a connector pin ⅝ inch in length. Removal of die block insert100bwill produce a connector pin ½ inch in length. Removal of die block insert100awill produce a connector pin ¼ inch in length. In this manner, by incorporating one or more of the die block inserts100a-100din die block88, the length of the connector pin62formed within die block88may be easily selected and precisely controlled.

Referring toFIG. 8, there is shown another arrangement as an alternative to a hydraulic cylinder or a rack and pinion combination for linearly displacing the various components in the two-stage cold heading die10of the present invention, such as the various shafts, displacement members and dies. The arrangement shown in the end-on view ofFIG. 8is an eccentric drive arrangement120, or, more specifically, an elliptical drive arrangement. Eccentric drive arrangement120includes first and second aligned, closely spaced cam wheels122aand122b.Plan side views of the first and second cam wheels122a,122bare respectively shown inFIGS. 8aand8b. A first rotary drive124ais attached to the first cam wheel122aby means of a first drive shaft125a.Similarly, a second rotary drive124bis coupled to the second cam wheel122bby means of a second drive shaft125b.The first and second drive shafts125aand125bare displaced in respective circles by means of the first and second circular drives124a,124b, respectively. Rotation of each of the first and second cam wheels122a,122babout a respective rotational axis define by its corresponding drive shaft125aand125bcauses the first and second cam wheels, including their respective center axes, to trace out an elliptical path during rotation. Each of the first and second cam wheels122a,122bis coupled to a respective needle bearing128aand128b,with the pair of needle bearings, in turn, attached to opposed ends of a common bearing shaft130. Each of the first and second cam wheels122a,12bincludes a respective circular slot126aand126bdisposed adjacent the cam wheel's outer peripheral surface, where the two peripheral slots are in facing relation with the two cam wheels positioned as shown inFIG. 8. Bearing shaft130is securely coupled to an end portion of an output shaft, or plunger,132as shown inFIG. 6. This allows the elliptical motion of the first and second cam wheels122a,and122bto be translated into reciprocating linear motion in the direction of arrows136aand136bwhere output shaft132is connected to any of the first through sixth cylindrical shafts20,22,23,24,26and27disposed within the die block12of the two-stage cold heading die10illustrated inFIG. 1. In the eccentric drive arrangement120, the portion of the rotational stroke traveled by the first and second drive shafts125a,125bdetermines whether the output shaft132is moving in a reciprocating manner in the direction of arrow134aor in the direction of arrow134b.

Referring toFIG. 9, there is shown another arrangement as an alternative to the multi-insert die block88shown inFIG. 7for controlling the length of the stroke of any of the first through fourth cylindrical shafts20,22,24and26for controlling the length of the connecting pin produced by the two-stage cold heading die10of the present invention. The arrangement shown inFIG. 9is a variable speed drive123for supplying, or providing, wire54to the two-stage cold heading die10. The variable speed drive arrangement123includes a variable speed electric motor131coupled to a reel of wire135by means of an input drive shaft133. Variable speed electric motor131imparts rotation to input drive shaft133for rotationally displacing a wheel upon which the metal wire135is disposed. The speed of electric motor131is controlled by a timer control switch127which is coupled to the variable speed electric motor by means of an electric lead129. The circular wheel122aupon which the metal wire135is positioned includes an outer, peripheral grooved portion126awithin which is positioned the metal wire. Also disposed on an inner portion of wheel122aare plural spaced apertures104a-104d.The variable speed drive arrangement123allows input drive shaft133to be securely connected in a rotatable manner to any of the four drive shaft mounting apertures104a-104d.Connecting the input drive shaft133to the outermost mounting aperture104dprovides the longest linear distance of travel of the metal wire135for providing a connector pin blank from the wire135of the greatest length for producing the longest connector pin, while attaching the input drive shaft133to the innermost drive shaft mounting aperture104awill produce the shortest connector pin. In the manner, by selectively attaching input drive shaft133to one of the drive shaft mounting apertures104a-104dwithin cam wheel122a,the length of the connector pin may be selected as desired. Again, by connecting this variable length drive123to metal wire54fed into the die block12of the two-stage cold heading die10, the length of the produced connector pin may be selected, as desired.

Having thus disclosed in detail several embodiments of the invention, persons skilled in the art will be able to modify certain of the structures shown and to substitute equivalent elements for those disclosed while continuing to practice the principles of the invention. It is, therefore, intended that all such modifications and substitutions be covered as they are embraced within the spirit and scope of the present invention as described in the claims.