Crimping Tool

Abstract

A crimping arrangement for attaching a contact to the end of a wire in which opposed first flat dies are moved inwardly to a position of spaced adjacency in which they compress the contact between them, after which opposed second dies with arcuate concave surfaces and of thicknesses equal to the spacing between the flat dies are moved inwardly to further compress the contact. The dies may be movable in straight slots in a carrier member and actuated by a rotatable cam ring having grooves receiving outer peripheries of the dies to cause the appropriate sequential movement. Handles attached to the cam ring and die carrier member permit hand operation of the tool.

Description

BACKGROUND OF THE INVENTION:

1. Field of the Invention

This invention pertains to the attachment of wires to electrical contacts by crimping.

2. Description of Prior Art

In attaching wires to the contacts of electrical connectors, crimping offers many advantages in speed and convenience. Hand operated tools have been designed to accomplish contact crimping, conventionally including four spaced indenters which are actuated simultaneously to engage the periphery of the contact. This produces four localized indentations in the contact at which locations it is deflected inwardly to grip a wire received within it. Examples of crimping tools of this type are found in U.S. Pat. Nos. 2,933,000, 2467,012, 3,049,951, 3,063,313, 3,201,969, 3,375,697 and 3,416,213.

Also, for crimping or other forming operations, the use of four members with arcuate concave surfaces has been proposed. Arrangements of this type are disclosed in U.S. Pat. Nos. 1,552,162, 3,084,571 and 3,451,249. Again, the members are urged inwardly at the same time to engage the surface of the contact or other member in compressing it. Necessarily, there are spacers between the adjacent indenters or other jaw members for engaging the contact. Irrespective of the shape of the operative surface, therefore, the inward force exerted by the indenting member causes the contact to bulge outwardly between adjacent jaws. An undesirably large overall lateral dimension can result, producing an obstruction to the insertion of a contact removal tool into the contact opening in an electrical connector plug or receptacle. The localized type of compression that is realized generates only a limited gripping force on the wire received in the contact. Under some circumstances, therefore, the wire may be pulled free from the contact, thereby destroying the electrical connection. Because the indenters produce only limited areas where the contact is pressed firmly against the surface of the wire, there can be a relatively high resistance to the flow of current between the contact and the wire.

SUMMARY OF THE INVENTION

The present invention provides an improved crimping arrangement in which the wire is much more securely retained, the electrical resistance is low and the overall lateral dimension of the contact end is reduced. In this arrangement, there are first opposed jaws or dies having adjacent flat surfaces. These dies are moved inwardly so that the flat surfaces engage the contact and deflect it to a generally oval configuration. Next, while the first dies are held in their positions of engagement with the contact, additional dies are moved inwardly to engage and compress the exposed sides of the contact. The second dies are of a width corresponding to the spacing between the first dies when in their inner positions. Thus, all portions of the contact are confined by the four jaws, and there can be no outwardly bulging portions. The second dies have arcuate surfaces, which are concave and defined by segments of cylinders which are less than semicylinders. The second dies are moved inwardly a predetermined distance to achieve an appropriate compression of the contact, which virtually eliminates any spaces within the makeup of the wire and the contact, providing instead essentially a homogeneous mass within the contact. The result is an exceptionally strong mechanical connection, low electrical resistance and reduced lateral dimension.

To actuate the dies, there may be provided a die carrier member having transverse slots which receive and guide the dies. A cam ring circumscribes the dies, engaging them at their outer peripheries. Initial movement of the cam ring causes the first dies to be forced out of cam grooves which normally receive them and to be moved inwardly so that they can engage the contact and will remain at a predetermined spacing. The cam grooves for the second dies include relative deep portions of finite length, which will not bias the second dies inwardly to any appreciable extent as the first dies are moved to their inner positions. Thereafter, however, with continued movement of the cam ring, the second dies are forced out of their cam grooves and accomplish the compression of the contact. Springs return the dies to their original positions when the cam ring is returned to its original location. The second dies may include independent rollers at their outer ends, which are the members engaged by the cam ring. The rollers can be varied in size to assure proper positioning of the second dies in the assembled tool. Also, the rollers reduce friction between the second dies and the cam ring so that movement of the second dies is facilitated.

The unit may be incorporated in a hand-operated tool in which the cam ring is rotated by one handle, while the carrier for the dies is movable with a second handle. An adjustable stop may be included to control the amount of rotation of the cam ring relative to the die carrier member, which, in turn, governs the degree to which the second dies are forced out of their cam grooves and, hence, the length of the stroke of the second dies.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a side elevational view of an electrical contact and associated wire which are to be secured together by crimping in accordance with the present invention;

FIG. 2 is a fragmentary elevational view showing the contact and the wire between the dies preparatory for the crimping operation;

FIG. 3 is a view similar to FIG. 2, but with the flat dies moved inwardly to engage the contact;

FIG. 4 is a view similar to FIGS. 2 and 3 illustrating the final stage of the crimping operation in which the curved dies are moved inwardly to engage the contact;

FIG, 5 is a perspective view of the contact after the crimping operation;

FIG. 6 is an enlarged transverse sectional view showing the wire in the contact barrel prior to crimping;

FIG. 7 is a view similar to FIG. 6, but after the crimping has taken place;

FIG. 8 is an elevational view of the crimping tool with one handle portion partially broken away and the cover plate removed for clarity;

FIG. 9 is a fragmentary elevational view of the forward portion of the crimping tool;

FIG. 10 is an enlarged fragmentary view of the crimping tool with the cover plate removed for clarity, illustrating the first stage of the crimping operation;

FIG. 11 is an enlarged exploded perspective view of the jaws, jaw carrier and cam of the crimping tool;

FIG. 12 is a sectional view taken along line 12--12 of FIG. 10;

FIG. 13 is a sectional view taken along line 13--13 of FIG. 10;

FIG. 14 is a sectional view taken along 14--14 of FIG. 10;

FIG. 15 is a sectional view taken along 15--15 of FIG. 10;

FIG. 16 is an enlarged fragmentary sectional view showing the contact received in the tool for the commencement of the crimping operation;

FIG. 17 is an elevational view of the crimping tool positioned in the first stage of the crimping operation;

FIG. 18 is an elevational view of the crimping tool positioned intermediate the first and second stages of the crimping operation, and

FIG. 19 is an elevational view of the crimping tool in the second stage of the crimping operation with both sets of jaws advanced inwardly.

DESCRIPTION OF THE PREFERRED EMBODIMENT:

The crimping arrangement of this invention will form an attachment between a wire 10 and a standard contact 11 of the type commonly used in electrical connectors, as seen in FIG. 1. The contact 11 includes an open cylindrical barrel end 12 that is adapted to receive the end of the wire 10 from which the insulation 13 has been stripped. An inspection opening 14 in the wall of the barrel 12 permits the wire 10 to be observed when it is within the barrel 12 so that it can be made certain that the wire has been inserted far enough. Beyond the barrel portion 12 of the contact 11 is an annular enlargement 15 defining rearward and forward shoulders 16 and 17, respectively, which normally are used in retaining the contact within the electrical connector. A forward projecting portion 18 extends from the enlargement 15, in the embodiment shown in FIG. 1 this being a pin which is to enter the opening of a mating socket contact. The invention will operate as satisfactorily with socket contacts, which also have similar open-ended barrel portions 12.

The connection between the wire 10 and the contact 11 is made by crimping the barrel portion 12 of the contact so that it grips the end of the wire. This is accomplished by the steps shown schematically in FIGS. 2, 3 and 4. The barrel portion 12 of the contact 11, with the end of the wire 10 received in it, is positioned between opposed dies 20 and 21, which have flat end surfaces 22 and 23. The contact barrel portion 12 also is located between a second pair of opposed dies 24 and 25, which lie in a plane which is perpendicular to a plane through the dies 20 and 21. The dies 24 and 25 have arcuate concave surfaces 26 and 27 adjacent the contact barrel end 12, these surfaces being identical cylindrical segments.

In the forming operation, first, the dies 20 and 21 are moved inwardly a predetermined distance to engage the contact barrel end 12, deflecting it so as to cause it to assume a generally oval contour as shown in FIG. 3. In the inner positions of these dies, the flat end surfaces 22 and 23 are spaced apart a distance less than the original outside diameter of the contact barrel 12, and substantially equal to the thickness of each of the dies 24 and 25. Therefore, the spacing between the die surfaces 22 and 23 corresponds to that between the flat sidewalls 29 and 30 of the die 24, and the similar sidewalls 31 and 32 of the die 25. At this time, the dies 24 and 25 are received between the surfaces 22 and 23, which facilitates the subsequent inward movement of the dies 24 and 25.

Next, with the dies 20 and 21 held in this position, the curved dies 24 and 25 are advanced toward each other. They are moved inwardly between the dies 20 and 21 to a position where the arcuate end surfaces 26 and 27 engage the exposed side portions of the contact barrel end 12, and advanced inwardly to compress the barrel end 12 of the contact around the end of the wire 10 (see FIG. 4). When so moved to their inner positions, the adjacent surfaces 26 and 27 of the dies 24 and 25 are spaced apart, but the contact barrel 12 is confined on all sides by these dies and the flat dies 20 and 21. There are no gaps through which portions of the contact can bulge outwardly. With the barrel 12 being compressed completely around the wire 10, the lateral dimension of the contact barrel is reduced in all directions. This completes the crimping operation, and the dies 20, 21, 24 and 25 then are removed from the contact.

After the crimping operation, the barrel end 12 of the contact has the general appearance shown in FIG. 5. This includes opposed flattened surfaces 34 and 35 where the contact has been engaged by the dies 20 and 21, and opposed curved portions 36 and 37 where the contact has been compressed by the dies 24 and 25.

FIGS. 6 and 7 are transverse sectional views illustrating the condition of the barrel portion 12 of the contact and the wire 10 before and after the crimping. The wire 10 consists of a number of individual strands 10a arranged in a group so as to have a generally cylindrical exterior. When the wire is fitted within the tubular barrel portion 12 of the contact 11, necessarily there are spaces around the various strands 10a. After the crimping operation, however, as shown in FIG. 7, the strands 10a are virtually indistinguishable, and the wire 10 presents almost a homogeneous mass, with no gaps either internally or between the exterior of the wire and the wall of the contact. This complete consolidation of the wire 10 and the contact results in an extremely strong mechanical connection between the wire and the contact. Also, there are large surface areas of the wire and contact in intimate engagement so that there is very low resistance to the flow of electricity. The reduced lateral dimension given the rearward barrel portion of the contact has a further advantage in that it facilitates the entry of the removal tool into the opening receiving the contact when the contact is assembled into an electrical connector. With the end of the contact being small in lateral dimension, there is no tendency for the tubular removal tool to catch on the contact before reaching the retention fingers within the connector.

The curved surfaces 26 and 27 of the dies 24 and 25 extend through arcs that are less than 180.degree. so that they are not quite semi-cylindrical. This allows the dies 24 and 25 to have adequate strength at the edges of the working surfaces 26 and 27. If the surfaces 26 and 27 were semicylindrical the dies would taper to feather edges where the curved surface 26 joins the flat sidewalls 29 and 30, and where the surface 27 meets the sidewalls 31 and 32. These thin edges inherently would lack strength. Also, where the final crimped shape of the contact is not made cylindrical, and the surfaces 26 and 27 are less than semi-cylinders, the edges of the dies 24 and 25 do not engage at the ends of their inward strokes. This further helps to avoid damage to the die surfaces.

The dies 20, 21, 24 and 25 may be arranged as jaws in the crimping tool 39, as seen in FIGS. 8, 10 and 17 through 19. This tool has general similarity to a pair of pliers, in that it is actuated by handles 40 and 41 when the contact is crimped.

As shown in particular in FIGS. 11 and 12, the crimping tool 39 includes a central die carrier 42, which has a short forward cylindrical portion 43 and a rearward cylindrical part 44 of reduced diameter. A relatively wide transverse slot 45 extends diametrically across the forward radial face 46 of the portion 43 of the carrier 42. Longitudinal slots 47 and 48 of the same width connect to the outer ends of the slot 45 and extend to the rearward end of the forward portion 43 of the carrier 42.

An additional narrower transverse slot 49 extends diametrically across the forward end of the carrier 42, being perpendicular to and of the same depth as the slot 45. Longitudinal slots 50 and 51 connect to the outer ends of the slot 49, are of the same width as that slot and extend to the rearward end of the forward portion 44 of the carrier 42.

The jaws 20 and 21 are L-shaped, having outer portions 52 and 53 and inner portions 54 and 55. When the jaws 20 and 21 are associated with the carrier 42, the inner portions 54 and 55 of these jaws are positioned in the transverse slot 45 and aligned radially of the tool. The outer portions 52 and 53 of the jaws 20 and 21 are located in the longitudinal slots 47 and 48, where they are engaged on their undersurfaces by compression springs 56 and 57. The latter members are received within openings 58 and 59 which extend radially with respect to the carrier 42 and are parallel to the slot 45.

The jaws 24 and 25 also are L-shaped, including outer portions 62 and 63 that fit within the longitudinal slots 50 and 51, while the inner portions 64 and 65 of these jaws are located in the transverse slot 49. Compression springs 67 and 68 received in radial openings 69 and 70 bear against the flat undersurfaces of the outer portions 62 and 63 of the jaws 24 and 25 (see FIG. 13).

A cover plate 72 having a circular outer periphery and a frustoconical opening 73 at its center fits over the forward face 46 of the carrier 42. It is attached to the carrier by means of screws 74, which fit within tapped openings 75 that extend longitudinally into the carrier 42. The cover plate 72 prevents the jaws 20, 21, 24 and 25 from falling out of the front of the carrier 42.

Extending around the carrier 42 is a cam ring 76 which has a cylindrical inner surface 77. The handle 40 of the crimping tool 39 is integral with and extends from the cam ring 76. A pair of diametrically opposed grooves 78 and 79 in the inner surface 77 extends for the length of the cam ring 76. The grooves 78 and 79 are formed by cylindrical segments which are less than semicylinders.

A second pair of diametrically opposed grooves 81 and 82 also extends the full length of the inner surface 77 of the cam ring 76. The grooves 81 and 82 are displaced 90.degree. from the grooves 78 and 79, and include sloping portions 83 and 84 leading to inner deeper portions 85 and 86.

The outer portions 51 and 52 of the jaws 20 and 21 have outer semicylindrical ridges 88 and 89 which are adapted to substantially complementarily enter the grooves 78 and 79 in the cam ring 76. The compression springs 56 and 57 urge the jaws 20 and 21 outwardly to normally hold the ridges 88 and 89 within the grooves 78 and 79. This is the retracted position of the jaws 20 and 21.

The outer parts 62 and 63 of the curved jaws 24 and 25 have beveled outer longitudinal surfaces 90 and 91 which lead to outer corners 92 and 93 that engage the inner surface 77 of the cam ring 76 adjacent the inner portions 85 and 86 of the grooves 81 and 82, when these jaws are retracted as shown in FIG. 8. The compression springs 67 and 68 for the jaws 24 and 25 urge these jaws outwardly into this position. Adjacent the beveled outer surfaces 90 and 91 of the jaws 24 and 25, and within the deeper groove portions 85 and 86, are small cylindrical rollers 94 and 95.

Extending around the rearward portion 44 of the carrier 42, adjacent the rearward radial face 97 of the carrier portion 43, is a flat plate 98. The latter member is connected to the carrier by dowel pins 99 that extend through longitudinal openings 100 in the forward carrier portion 43. An arm 101 is integral with the plate 98 and projects from it.

The handle 41 is in three pieces, two of which are outer, generally flat sections 102 and 103. The section 102 has an opening 104 that receives the end of the rearward portion 44 of the carrier 43, positioning this part of the handle adjacent the plate 98. The other outer handle portion 103 has an inner opening 105 that fits around the cover plate 72. Outwardly from the jaw area there is a spacer 106 intermediate the handle sections 102 and 103, and the handle assembly is held together by fasteners 107.

A bore extends axially through the die carrier 42, the bore including a forward portion 109 and an enlarged threaded rearward portion 110, with a radial shoulder 111 between. A contact positioning member 112 has a threaded shank 113 that fits within the threaded portion 110 of the bore, and a radial shoulder 114 that engages the shoulder 111 of the bore. Beyond this is an unthreaded end portion 115 of the shank that is of reduced diameter and extends into the forward part 109 of the bore, but is spaced inwardly from the bore entrance. An axial cylindrical opening 116 is provided in the shank 113 of the member 112, extending inwardly from the forward radial face 117 of the shank. At the opposite end of the member 112 is a knob 118, allowing the member 112 to be rotated into position where the shoulders 111 and 114 are in interengagement.

In use of the crimping tool 39, the end of the wire 10 is fitted into the barrel end 12 of the contact 11, and the forward end 18 of the contact is extended into the axial opening 116 of the member 112. The contact is advanced into the opening 116 a distance sufficient to cause its forward shoulder 17 to engage the radial end face 117 of the member 112, as shown in FIG. 16. The parts are proportioned so that in this position of the contact 11 its enlarged portion 15 and the forward part of the barrel end 12, where the inspection hole 14 is located, are within the forward portion 109 of the bore in the carrier 42. However, the remainder of the barrel end 12 extends outwardly beyond the bore and is received within the space between the flat jaws 20 and 21 and the curved jaws 24 and 25. The rearward end of the contact is positioned just in-wardly of the outer edges of the jaws.

After this, the handles 40 and 41 are rotated relative to each other to accomplish the crimping operation. In sequence, rotation of the cam ring 76 in the counterclockwise direction, as the device is illustrated, effected by movement of the handle 40, initially causes the carrier 42 to rotate with it in the same direction. This occurs because the outer ridges 88 and 89 of the jaws 20 and 21 fit within the grooves 78 and 79 of the cam ring 76, coupling the jaws and, hence, the carrier to the cam ring. This simultaneous rotation occurs for only a few degrees until the arm 101 of the plate 98, which is connected to the carrier 42 by the dowels 99, engages a stop 120 carried by the handle 41 between its side portions 102 and 103 (see FIG. 8). This prevents further rotation of the carrier 42 so that the cam ring 76 then must turn relative to the carrier. As this relative rotation takes place, the reaction at the cam grooves 78 and 79 immediately forces the ridges 88 and 89 of the jaws 20 and 21 out of these grooves. This drives the jaws 20 and 21 inwardly in the path defined by the transverse slot 45 in opposition to the springs 56 and 57. This inward movement of the jaws 20 and 21 causes their opposed flat surfaces 22 and 23 to engage the periphery of the barrel end 12 of the contact, deflecting the barrel end to a generally oval shape, as shown in FIG. 3 and discussed above. This position of the tool is illustrated in FIGS. 10 and 17. This accomplishes the first step of the crimping operation.

At this time, the rollers 94 and 95 are moved by the cam ring 76 to locations outwardly of the beveled end surfaces 90 and 91 of the jaws 24 and 25. However, the rollers 94 and 95 still are within the deeper portions 85 and 86 of the grooves 81 and 82 so that the jaws 24 and 25 remain substantially in their original positions. Consequently, only the jaws 20 and 21 initially are activated, while the other jaws 24 and 25 stay retracted.

Continued rotation of the cam ring 76 in the counterclockwise direction, as the invention is illustrated, brings the inclined portions 83 and 84 of the grooves 81 and 82 to bear against the rollers 94 and 95, as shown in FIG. 18. When this occurs, the surfaces 83 and 84 cam the rollers 94 and 95 inwardly with respect to the transverse slot 49 in the carrier 43. This, in turn, forces the jaws 24 and 25 inwardly toward the contact 11.

Further counterclockwise movement of the cam ring 76 brings it to the position of FIG. 19, where the rollers 94 and 95 are forced nearly all the way out of the grooves 81 and 82. This causes the arcuate surfaces 26 and 27 of the jaws 24 and 25 to engage and compress the sides of the contact barrel end 12. During this time, the outer ridges 88 and 89 of the other jaws 20 and 21 slide along the cylindrical inner surface 77 of the cam ring 76. This maintains the jaws 20 and 21 in their inner position, where they are held as the jaws 24 and 25 complete the crimping operation.

The handles 40 and 41 then are released and the parts of the crimping tool are returned to their original positions. A telescoping link 121 interconnects the handles 40 and 41 and contains a compression spring so that it biases the handles to their separated position. The link 121 also includes a ratchet which will not allow the handles to release until they have been advanced a full stroke relatively toward each other, to assure that a complete crimping operation is accomplished. This type of link is conventional in hand crimping tools.

The stop 120 is adjustable to vary the amount of rotation permitted the plate 98, its arm 101 and, therefore, the carrier 42. This, in turn, governs the total travel of the curved jaws 24 and 25. The stop 120 is mounted on a pin 122 and is rotatable by a knob 123 relative to the handle 41. The stop 120 includes a series of flat surfaces 124 on its exterior which are at different distances from the axis of the pin 122. Rotation of the stop 120, therefore, can place a selected flat surface 124 adjacent the arm 101.

When a particular contact size and configuration requires maximum movement of the jaws 24 and 25, the surface 124 farthest from the axis of the pin 122 is positioned adjacent the arm 101. In the example shown in FIG. 8, this is the surface at the left-hand portion of stop 120. This allows only minimal rotation of the arm 101, after which it and, therefore, the carrier 42 are prevented from movement. Consequently, during a maximum portion of the stroke of the handle 40, the cam ring 76 moves relative to the carrier 42. This greater relative rotation of the cam ring causes the rollers 94 and 95 to be forced farther out of the grooves 81 and 82 by the time the stroke of the cam ring is completed. The inclined surfaces 83 and 84 of the grooves 81 and 82, therefore, drive the rollers 94 and 95 and, hence, the jaws 24 and 25 inwardly a maximum distance. This provides the greatest degree of compression on the barrel end 12 of the contact 11.

On the other hand, if the stop 120 is positioned so that the surface 124 closest to the axis of the pin 122 is located adjacent the arm 101, there will be the greatest amount of movement of the carrier 43 with the cam ring 76. The resulting lesser amount of relative rotation causes the rollers 94 and 95 to move only part way down the sloping cam surfaces 83 and 84. This cams the rollers 94 and 95 inwardly a minimum distance and produces less compression of the barrel and 12 of the contact.

A dial 124 and index marking 125 are provided on the exterior of the handle portion 103 so that appropriate adjustment of the stop 120 is readily effected.

The foregoing detailed description is to be clearly understood as given by way of illustration and example only, the spirit and scope of this invention being limited solely by the appended claims.

Claims

I claim:

1. The method of attaching a wire to an electrical contact having an open tubular end portion comprising the steps of

providing a first set of opposed dies with opposed first surfaces adapted to engage said tubular end portion, providing a second set of opposed dies with opposed second surfaces adapted to engage said tubular end portion, inserting the end of a wire into said tubular end portion, then urging said first set of opposed dies inwardly to a position where said first surfaces engage and compress a first part of said end portion therebetween, and then maintaining said first dies in said position and simultaneously urging said second set of opposed dies inwardly to a position where said second surfaces engage and compress a second part of said end portion therebetween.

2. The method as recited in claim 1 in which said second dies are displaced substantially 90.degree. from said first dies.

3. The method of attaching a wire to an electrical contact having an open tubular end portion comprising the steps of

providing a first set of opposed dies with opposed first surfaces adapted to engage said tubular end portion, providing a second set of opposed dies displaced substantially 90.degree. from said first dies,

said second dies having opposed second surfaces adapted to engage said tubular end portion,

inserting the end of a wire into said tubular end portion,

then urging said first set of opposed dies inwardly to a position where said first surfaces engage and compress a first part of said end portion therebetween,

and then maintaining said first dies in said position and simultaneously urging said second set of opposed dies inwardly to a position where said second surfaces engage and compress a second part of said end portion therebetween,

said second dies at said second surfaces thereof being made to a width substantially equal to the spacing between said first surfaces of said first dies and received between said first surfaces when said first dies are in said position thereof.

4. The method as recited in claim 3 in which said first surfaces are made substantially planar.

5. The method as recited in claim 4 in which said second surfaces of said second dies are made arcuate.

6. The method as recited in claim 5 in which said second surfaces of said second dies are made to define cylindrical segments which are less than semicylinders.

7. The method as recited in claim 3 in which said second dies are spaced apart when said second dies are in said position thereof.

8. The method as recited in claim 3 in which said contact is provided with an inspection opening through said tubular portion, and in which said first pair of opposed dies and said second pair of opposed dies so engage and compress said first and second parts of said tubular portion only outwardly of said inspection opening.

9. A device for attaching a wire to an electrical contact or the like having a tubular end portion by crimping said end portion while said wire is received therein comprising

a duality of first dies having spaced opposed first surfaces,

a duality of second dies having spaced opposed second surfaces,

said first and second dies collectively defining an opening adapted to receive an electrical contact,

means for moving said first dies relatively toward each other along a first path to a position in which said first surfaces are in spaced adjacency for engaging and compressing an electrical contact therebetween,

and means for then holding said first dies in said position and simultaneously moving said second dies relatively toward each other along a second path to a position in which said second surfaces are in spaced adjacency for further compressing said electrical contact there-between.

10. A device as recited in claim 9 in which said first path and said second path are angularly spaced apart substantially 90.degree..

11. A device as recited in claim 10 in which said first surfaces are planar.

12. A device as recited in claim 11 in which said second surfaces are arcuate.

13. A device as recited in claim 12 in which said second surfaces are defined by cylindrical segments which segments are less than semicylinders.

14. A device as recited in claim 13 in which said second surfaces are spaced apart when said second dies are in said position thereof.

15. A device as recited in claim 10 in which said first surfaces when said first dies are in said position thereof are spaced apart a distance substantially equal to the widths of said second dies and said second dies are received therebetween, whereby said second dies are movable between said first surfaces to said position of said second dies

16. A device as recited in claim 13 in which said means for moving said first dies comprises a first cam means.

17. A device as recited in claim 16 in which said means for moving said second dies comprises a second cam means.

18. A device as recited in claim 17 including an annular member circumscribing said first and second dies and rotatable relative thereto, said first and second cam means being incorporated in said annular member.

19. A device as recited in claim 18 in which

said first cam means is defined by a longitudinally extending groove in said annular member adjacent each of said first dies,

each of said first dies having a portion receivable in the one of said grooves adjacent thereto,

said portions being displaceable out of said grooves upon predetermined rotation of said annular member relative to said dies.

20. A device as recited in claim 19 in which said means for maintaining said first dies in said position thereof comprises the inner periphery of said annular member adjacent said first grooves therein.

21. A device as recited in claim 19 in which

said second cam means is defined by a second longitudinal groove adjacent each of said second dies,

each of said second dies having a portion receivable in one of said second grooves, said portions being displaceable out of said second grooves upon rotation of said annular member relative to said dies by an amount greater than said predetermined rotation.

22. A device as recited in claim 21 in which each of said second dies includes a first member having said second surface thereon, and a roller at the opposite end of said member for engagement with said annular member at said second groove therein.

23. A device as recited in claim 22 in which

each of said second grooves includes a first relatively deep portion, and a second sloping shallower portion,

said relatively deep portion being dimensioned to receive said roller during said predetermined rotation of said annular member relative to said dies,

whereby said second dies are not forced inwardly to said position thereof as a result of said predeter-mined relative rotation.

24. A device as recited in claim 23 in which said means for rotating said annular member relative to said dies includes a duality of hand-operable handles.

25. A device as recited in claim 19 in which

said means for moving said first cam means along said first path and said second cam means along said second path includes a member having first slot means therein receiving said first dies and second slot means therein receiving said second dies,

said first and second slot means being spaced apart angularly substantially 90.degree..

26. A device as recited in claim 25 in which

said first slot means includes a substantially radial portion, and a substantially longitudinal portion at either end of said substantially radial portion thereof,

said second slot means includes a substantially radial portion, and a substantially longitudinal portion at either end of said substantially radial portion thereof,

each of said first dies being substantially L-shaped with a first portion in said substantially radial portion of said first slot means and a second portion in one of said substantially longitudinal portions of said first slot means,

each of said second dies being substantially L-shaped with a first portion in said substantially radial portion of said second slot means and a second portion in one of said substantially longitudinal portions of said second slot means, and including spring means engaging said second portions of said first and second dies for biasing the same toward said annular member.