US2359083A - Tool for making electrical connectors - Google Patents

Description

P 1944- v. E. cARLsoN 2,359,083

TOOL FOR MAKING ELECTRICAL CONNECTORS Filed Aug. 17, 1942 2 Sheets-Sheet 1 3! INVENTOR K: arr/E arls 11/ BY A'rr RNE.

Patented Sept. 26, 1944:

TOOL

Vernon E. Carlson,

Aircraft-Marine ron mxmc ELECTRICAL CONNECTORS Short Hills, N. J., assignor to Products, 1110., Elizabeth, N. J.,

a corporation of New Jersey,

Application August 17, 1942, Serial No. 455,033

13 Claims.

This invention relates to a method of closing, crimpin or otherwise compressing a ferrule or the like and to a crimping or closing tool adapted particularly for closing, crimping, or otherwise compressing the ferrule portion of a connecting member onto the insulation of an electrical conductor.

It has been common practice before my invention to secure ferrules, thimbles, etc. in place by crimping and this has been practiced in particular in applying terminals to insulated wire by crimping a ferrule or sleeve portion of the terminal after an insulated portion of the wire has been inserted into it. Such crimping, however, has ordinarily involved the forming of one or more re-entrant folds in the ferrule with the result that either the insulation is very severely deformed or the ferrule is not securely held on and sealed to the Wire.

It is an object of the present invention to provide a simple and direct compression of a. ferrule or like member to reduce its periphery without folding or other severe deformation.

Another object of the invention is to provide for the compression or crimping of a ferrule or the like by a simple press or hand tool.

Another object of the invention is to provide for crimping a ferrule onto a flexible tube or sheath with production of a final form so close to a circular form as to avoid injury to a tube or sheath and to assure continuous engagement thereof, and of such reduced periphery, as to make a fluid-tight seal thereto.

Another object of the invention is to provide for applying to an insulated conductor a terminal of the type having an inner ferrule for engaging and contactingthe central conductor and an outer ferrule or sleeve fitted over the inner ferrule and extending therebeyond to receive and support the end of the insulation on the Wire, and it is also an object so to compress this extended portion about the insulation as to secure them and seal them together without substantially weakening or damaging either.

I have discovered that if the ferrule or other article to be crimped is properly supported during the crimping operation, the pressure may be so exerted peripherally on the ferrule as actually to compress the metal and reduce the peripheral dimension without any sharp folding or collapsing of the portions crimped. Thus, a portion of the ferrule can be so constricted onto an insulated wire or other member as to assure a per manent engagement and even a fluid-tight seal thereto.

the pins :2 and 33 In these drawings, I have shown and described a preferred embodiment of my invention and various modifications thereof; but it is to be understood that these are not intended to be exhaustive nor limiting of the invention but on the contraryare given for purposes of illustration in order that others skilled in the art may fully understand the invention and the principles thereof and the manner of applying it in practical use so that they may modify and adapt it in various forms, each as may be best suited to the conditions of a particular use.

In these drawings, in which like reference characters refer to similar parts:

Figure 1 is a plan view of a novel and improved hand tool embodying the invention;

Figure 2 is a longitudinal section through a terminal being crimped and a cross section through the tool shown in Figure 1;

Figure 3 is a perspective of the tool of Figure 1 but showing it from the other side;.

Figure 4 is a perspective of a crimped terminal;

Figure 5 is a plan view of a modified form of a novel and improved hand tool embodying the invention;

Figure 6 is an enlarged sectional view of a portion of the tool illustrated in Figure 5; p Figure 7 is a plan view of a further embodiment of the invention; and

Figure 8 is a cross section taken on line 3-8 of Figure 4.

In Figures 1 through 3 I have shown a hand tool designed particularly for applying terminal connectors to insulated wire. A pair of handles 20 and 2| are indicated pivotally connected to one another by the pin 40, and are normally held opened, 1. e., spread apart, by the spring 4|. Handles 20 and 2|, respectively, are pivoted to jaws 24 and 25 by pins 38 and 39. The jaws 24 and 25 are pivoted on an aligning bearing 34 and are pivotally connected together by two links 35, the upper one of which has been removedin Figure 1. These links are held to the respective faces of the jaws 24 and 25. and pivotally connected to them by pins 32 and 33, respectively. The bearing 34, being located in a recess of the jaws 24 and 25, as illustrated, is retained in its proper position axially by intermediate portions of links 35.

As handles 20 and 2| are moved toward one another about the axis of pin 40 pins 38 and 39 are moved away from one another and with them the adjacent ends of the laws 24 and 25. Since are maintained in a predetermined spaced relationship by links 35, this movement of the ends of jaws 24 and 25 must be a rocking movement, whereby upper portions thereof are moved toward one another. The

jaws are so designed that, during movement of the handles 28 and 2| and the resulting movement of jaws 24 and 25, the same bearing relationship is maintained between jaws 24 and 25 and bearing 34.

The faces 28 and 21 (see Figure 3), respectively, of the jaws 24 and 25 meet when handles 28 and 2| are squeezed and thus limit the extent to which jaws 24 and 25 may be brought together. If desired, the crimping dies of my present invention may be formed in the jaws 24 and 25 adjacent to the faces 28 and 21. As shown, however, these jaws 24 and 25 are formed in accordance with the invention of U. A. Whitaker, described and claimed in a copending application, Serial No. 455,039 filed herewith, t crimp the heavier ferrule 38 onto the central conductor 22 of the wire W, while the crimping of the extended sleeve 3| onto the insulation 23 is performed by overlying die plates 28 and 29. Plate 28 is pivoted on jaw 24 by means of pin 32 and plate 29 is pivoted on jaw 25 by pin 33. Removable bolts 18 and 19, or other fastening means, fix the angular relationships between the plates 28 and 29 and the jaws 24 and 25, respectively. Different positioning of the plates 28 and/or 29 on their jaws to accommodate different sized ferrules or wire is attained by putting the bolt 18 into different holes 18, H or 12 of plate 28 and bolt I9 into different ones of the holes 13, I4, or 15, since underlying holes in jaws 24 and 25 into which the bolts 18 and I9 align, respectively, with the holes 18, 1|, i2, 13, I4, and 15 of plates 28 and 29, each give different angular positions of the plates.

Plate 29 is provided with a projection designed to fit into recess 58 of plate 28 when the two plates are moved toward one another. Likewise, plate 28 is provided with a projection 54 arranged to fit into a recess 55 of plate 29 when the plates are moved toward one another. Between these fitted portions on each of the plates 28 and 29 are die surfaces 58 and 58, respectively, each'of which is concave between the base of the adjoining projection 5| or 54 and the s de of the adjoining recess 58 or 55. The arrangement is such that as plates 28 and 29 are moved toward one another by pressing handles 28 and 2| together, the projection 5| overlaps plate 28 in the recess 58 and projection 54 overlaps the plate 29 in the recess 55 so that a space is enclosed between the overlapping portions and the die surfaces 58 and 59. As the die surfaces 58 and 59 are made further to approach each other this space is narrowed and any ferrule or other article engaged in the opening is required to conform itself to this decreasing area and periphery.

The surfaces of overlapping projection 5| and of the recess 58 are, when the space is first enclosed, at an angle to one another and are gradually brought into parallelism and eventually into full contact as the jaws are closed. This results in a compression of the space between die surfaces 58 and 59 in a direction transverse to their closing motion. Moreover, the ends of the projections 5| and 54 are rounded so that, if a relatively large ferrule, etc., is being engaged between the die surfaces 58 and 59, it will first be subjected to a lateral compression by camming action of these rounded ends even before the space between them is closed; and the ferrule may thus be compressed so as to fit into said space. After the rounded portion passes the corner of the opposite die, the ferrule is supported at the edges while it is being compressed between the die surfaces 58 and 59. Due to the smooth, concave form of the die surfaces with no re-entrant or projecting part which could start an unsupported buckling, the effect of such compression is to reduce the periphery by actual compression of the metal, whereas if the metal were once allowed to buckle inwardly or to escape into any gap within the dies, the compressive stress would be relieved and it would merely produce a sharp fold. At these opposite ends the surfaces 58 and 59 are formed with narrow steps 68, BI, 82 and 53. Because these are so close to the lateral faces of the projections 5| and 54, respectively, any inward folding or buckling which might otherwise result receives immediate support from the lateral faces and thus cannot relieve the peripheral compressive stress. On the contrary the provision of these opposed steps enables the opposite dies to gain a firm hold on the lateral portion of the ferrule and subject it to a very intense local compression. This is clearly shown in Figure 8 wherein the lateral portions 54 and which have been compressed between the steps 88-53 and 6|62, respectively, have been appreciably thickened in cross section as compared with the upper and lower portions of the ferrule. The use of the diamond form instead of a smooth arcuate curve also. helps in attaining the desired compression since the flattening of the ferrule wall from its arcuate form to the fiat faces of the diamond form takes advantage of the high mechanical advantage of a toggle action. This in turn flattens the lateral portions of the ferrule against the die portions 5| and 54 and assures against buckling or folding of ferrule in these portions. I

In order to give a close fit between the projections 5| and 54 and the recesses 58 and 55, the

bearing member 34 may be made slightly smaller than the bearings which receive it. Thus, as the jaws are closed together, plates 28 and 29 may shift slightly along the radius of their movement to allow the projections to match closely in said recesses.

When the jaws are opened, the projection 5| moves away from the side of the crimped ferrule and thus the ferrule is released for easy removal from the die.

In Figure 2 the tool is shown in use for applying a terminal connector C to an insulated wire W. In this use the insulation 23 is first stripped off for a short distance from the end of the central conductor 22 and onto this end is fitted the terminal connector, the connector shown in these figures being one more fully described and claimed in copending applications, Serial No. 421,408, filed December 3, 1941, and Serial No. 459,624, filed September 24, 1942.

This connector consists of a terminal contact portion l9 of standard form, a main ferrule 88 integral therewith, and a longer ferrule or sleeve 3| fitted over the main ferrule and extending beyond it to receive and support the insulated part of the wire. The ferrule 38 may be closed or open at the end next to the contact portion 9, and may be seamless or rolled. Also a single, stepped ferrule may be used instead of the ferrule 38 and overlying sleeve 3|.

A jig I84 attached to one of the jaws, as shown in Figures 2 and 3, receives the contact portion l9 of the terminal into the recessed end of the slide I85, which is adjustable in a slot I85 by Tborder will be left flaring slightly from the crimped section and the crimped sleeve will thus give a smoother support to the insulation with no tendency to cut or break the insulation at the end of the sleeve by repeated flexing. A flat spring I08 is advantageously used within the recessed end of slide I05. The spring is stiff enough to limit the position of the terminal connector, but is sufficiently flexible to accommodate the elongation of the ferrule which results from crimping and, thus, to avoid any flattening of the end of the contact portion 19.

.The die surfaces 58 and 59 of plates 28 and 29 are slightly sloped from the side on which the jig I04 is mounted and, thus, they provide a slight taper to the crimped portion of a ferrule so that there will be a gradual merging from the cylindrical, uncrimped section of the ferrule to the most severely crimped section, as shown in Figure 4. Furthermore, any tendency to sheer the ferrule by sharp concentration of stresses at the edge of the die during the crimping operation is limited by the tapered configuration presented by the die surfaces.

Although there is much advantage in the par ticular construction shown in Figures 1 to 3, my broad invention may be embodied and practiced with other and simpler structures. Figures 5 and 6 give one illustration of this. The modified form of hand tool shown in Figure 5 uses instead of the overlapping projections 5| and 54, blocks of rubber or other deformable material, and instead of the double lever system shown in Figure 1 the handles a and 2la are integral with jaws a and 24a, respectively, as in pliers construction. The surface of jaw 24a is recessed at a and a and the opposite jaw 25a is provided with two rubber blocks Ma and 54a set in and projecting from the jaw surface. Blocks Ma and 54a are received only partially by recesses 50a and 55a when the jaws are closed so that when the handles are fully squeezed together the rubber of these blocks is extruded into a space between them. Between the recesses of jaw 24a and blocks of jaw 25a there are shown cylindrically shaped die surfaces 581; and 59a for receiving and crimping a ferrule. The die surfaces 58a and 59a may be sloped from side to side, as already described in connection with Figures 1 to 3, or may be rounded to a minimum diameter near the center of their thickness with greater diameter at each side.

In the use of this tool, a ferrule which is to be fastened to an electrical conductor and which has been positioned over the end of an electrical conductor is positioned between the projections Sla and 54a. Jaws 24a and 25a are then closed tightly upon the ferrule and the ferrule is pressed into the space between the die surfaces 58a and 59a which, being in part at least of smaller diameter than the ferrules, crimp it onto the insulation of the conductor. The portions of projections 5m and 54a which are extruded into the space defined by die surfaces 58a and 59a are exposed to the edges 'of the ferrule, which would have to spread laterally if the. ferrule were merely flattened by the pressure applied. Since, however, there is no place for the rubber to go when the recesses 50a and 55a are fllled except to be squeezed into the space bounded by die surfaces 58a and 59a and since a ferrule located between the die surfaces presents a more yield- 'able mass than the jaws which otherwise surround the rubber blocks, the rubberis actually pressed into the ferrule, crimping it and/or supporting it against spreading and flattening.

When the jaws are again opened the rubber draws back to its normal form and the ferrule is released for easy removal from the die.

Figur 7 illustrates a section through jaws'llb and 25b of a hand tool of the same general type as that illustrated in Figure 1, corresponding parts bearing the same reference numerals with the addition of b. In this case, however, the die surfaces 58b and 55b instead of being V- shaped are half round and the die is shown in use for closing, instead of (or prior to) crimping, a ferrule. I

The die surfaces of each of the embodiments described are so arranged that a ferrule compacted therebetween may easily be removed after a compacting operation. The die surfaces are separable so that the crimped ferrule has only to be lifted out of the tool. Because of the overlapping configurations of the jaws associated with the die surfaces, however, there is no place for the metal of the ferrules to go during the compacting operations so that each ferrule is simply compacted, without extruding or folding, into the insulation of the electrical conductor to which it is to be connected. The result is that each ferrule is permanently bonded to the insulation of the electrical conductor with a secure, watertight seal.

The die surfaces of the tool illustrated in Figures 1 to 3 will impress a crimp which is more or less hexagonal in cross section. The tools illustrated in Figures 5, 6 and 7 will form a crimp more or less circular in cross section. In so far as the broad invention is concerned it isimmaterial just what the cross section of a crimp may be. Broadly, the invention encompasses tools wherein, as the die surfaces are brought together, the perimeter of the ferrule which is to be crimped is given support so that folding or extruding of th ferrule with respect to the die surfaces is impossible and so that a compressed portion of reduced dimensions results.

From the foregoing it will be seen that crimping devices made in accordance with the present invention are well adapted to attain the ends hereinbefore set forth and to be economically manufactured.

I claim:

1. In apparatus of the class described, a pair of compression dies having concave surfaces free from substantially inwardly projecting areas, said dies including means for providing lateral support to work between said die surfaces, whereby the work compressed between the die surfaces is subjected to compressive strains while substantially its entire periphery is supported against buckling or collapsing, and resilientmeans for freeing the work from the dies after compression therebetween, whereby the work may easily be removed therefrom.

2. In apparatus of the class described, a pair of compression dies having concave surfaces free from substantially inwardly projecting areas, said dies including means for providing lateral support to work between said die surfaces, said means including elastically deformable, incompressible inserts at the sides of said concave die surfaces, and means for imposing a compressive force on said inserts whereby to exert through them a lateral force against the work under compression between the die surfaces, whereby to aid in reducing the cross sectional area between the die surfaces as the dies approach one another.

3. In apparatus of the class described, a pair of compression dies having concave surfaces free from substantially inwardly projecting areas, said concave die surfaces being less than semi-circular and said dies including resilient means for aiding in freeing work therefrom after compression therebetween, whereby work being formed between the dies is readily released when the dies are moved away from one another, and said dies including means for providing lateral support to work being formed between said die surfaces, whereby the work may be compressed between the die surfaces with substantially full peripheral support against buckling or collapsing.

4. A tool for crimping a ferrule, said tool having opposing jaw members provided with die portions for compressing the ferrule, each of said jaw members including a projecting portion for cooperating with a die portion to afford a lateral support and at least one of said projecting portions having its edge toward the die portion sloped away from the die portion along its direction of movement, whereby taproduce a camming action on the ferrule as they die portion is moved to apply pressure to the ferrule, each of said die portions having a shallow V-form and each of said projecting portions having a substantially fiat surface, whereby when said jaw members are opened the compacted ferrule may easily be removed from the tool.

5. A tool for crimping a ferrule, said tool having opposing jaw members provided with concave die surfaces for peripherally compressing the ferrule and said jaw members including means extending across the ends of the recess between said concave surfaces and interfitted with the edges of said dies for giving lateral support to the ferrule as it is compressed by the dies, whereby the ferrule may be compressed with substantially full peripheral support against buckling or collapsing, said dies being sloped in a direction parallel to the axis of the die, whereby to give a tapered configuration to the ferrule.

6. A tool for crimping one end of a ferrule, said tool having opposing jaw members provided with concave die surfaces for peripherally compressing the ferrule, said jaw members including means extending across the ends of the recess between said concave surfaces and interfitted with the edges of said dies for giving lateral support to the ferrule as it is compressed by the dies, whereby the ferrule may be compressed with substantially full peripheral support against buckling or collapsing, said dies being sloped in a direction parallel to the axis of the die, whereby to give a tapered configuration to the die, and one of said jaw members including a jig for positioning and adjustable on said jaws with respect to said stop portions so as to predetermine the extent of compression to which said ferrule may be subjected by said dies, differently for different ferrules, said means including a plurality of holes in said die plates and jaws respectively. one pair of holes being aligned in each adjustment of a die plate on its jaw and locking pins adapted to be secured in any of said aligned holes, whereby different adjustments may be made selectively by holding different sets of holes in alignment with the looking pins.

8. A tool for compacting a ferrule, said tool having opposing jaw members provided with concave die portions for compressing the ferrule between them and including cooperating, interfitted portions for giving support to the ferrule as the die portions approach one another, said interfitted portions including at least one rubber element adapted to be squeezed between said jaws and thereby extruded against the ferrule as the die portions approach one another whereby to counteract the tendency of the ferrule to extrude or buckle between said dies.

9. A crimping tool of the type having a pair of compression dies each having thereon a concave die face, a projecting portion at one side thereof provided with a face extending from said concave face, adapted to form a lateral die face parallel to the path of movement of the dies when closed together, and overlapping the side of the other die to close said recess, and each die having its other side fitted to said overlapping face of the opposite die so as to engage it slidably during the final operations of said dies, said tool being characterized by the recess-forming portions of said dies having die surfaces composed of a series of major faces which substantially surround said recess, each of said faces being oriented with respect to the adjacent major faces at not substantially more than and said recess being free from any inwardly directed projection capable of effecting an unsupported buckling of the ferrul wall.

10. A crimping'tool as defined in claim 9 in which the die surfaces respectively are provided with narrow steps close to the lateral die faces, respectively, whereby lateral portions of the work are engaged between said steps and thereby subjected to intense local peripheral compression.

11. A crimping tool as defined in claim 9 in which the major die surfaces are substantially planar, whereby closing of the dies imposes intense peripheral compression on the work.

12. A crimping tool as defined in claim 9 in which the major die surfaces are substantially hexagonally arranged planar faces, whereby closing of the dies imposes intense peripheral compression on the work.

13. In apparatus of the class described, a pair of compression dies having concave surfaces free from substantially inwardly projecting areas, said dies including means for providing lateral support to work between said die surfaces, whereby the work compressed between the die surfaces is subjected to compressive strains while substantially its entire periphery is supported against buckling or collapsing; said apparatus being characterized by the fact that the means for providing lateral support are resiliently, relatively, slightly moveable with respect to one another, whereby after a compression operation the work may easily be removed from the dies.

VERNON E. CARLSON.

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