US2878854A

US2878854A - Wire gripping crimping dies with rib receiving grooves

Info

Publication number: US2878854A
Application number: US585362A
Authority: US
Inventors: Hugh W Batcheller
Original assignee: KENT Manufacturing CORP
Current assignee: KENT Manufacturing CORP
Priority date: 1956-05-16
Filing date: 1956-05-16
Publication date: 1959-03-24
Anticipated expiration: 1976-03-24

Description

March 24, 1959 H. w. BATCHELLE-R 2,878,854

WIRE GRIPPING CRIMPING DIES WITH RIB RECEIVING cRoov s Filed May Is, 1956 United I States Patent WIRE GRIPPING CRIMPING DIES WITH RIB RECEIVING GROOVES Hugh W. Batcheller, Newton, Mass.,assiguor to Kent Mfg. Corp., Newton, Mass., a corporation of Massachusetts Application May 16, 1956, Serial No. 585,362

2 Claims. (Cl. 153-1) This invention relates to dies for crimping electrical terminals onto wires to make a permanent connection between a terminal and a wire which will be mechanically strong and electrically eflicient. Electric terminals are secured to wires in a variety of ways the commonest of which is by being crimped. For this purpose the clip portion of the terminal which is to be crimped about a die being a stationary anvil with a cylindrically hollowed seat on which the clip to be crimped is placed. The upper die or rolling tool has a bottom face consisting of two planes which converge upwardly and merge in a cylindrical curve having a curvature equal to that of the clip portion of the terminal after it has been crimped about a wire. Any amount of pressure short of injuring the wire may be applied between the dies in the crimping operation, but to have a good mechanical and electrical connection the wire must be strongly gripped after the dies have been separated and the crimped metal has relaxed. The amount of such relaxation depends largely on the stiffness of the elements which are crimped. If these elements are made of stock that is too thin, for example, the grip on the wire may be too weak for a good mechanical connection, and the electrical resistance of the connection may sooner or later become excessive. To obtain a better grip with stock of any weight, the elements which are to be crimped about the wire may be stifiened by indenting one or more grooves in the inner face thereof with resultant ribs or ridges projecting from the outer face thereof. These ribs are arranged so that when the clips are crimped about a wire, the ribs will extend circumferentially around the wire. To avoid flattening of the ribs by the crimping dies, the active faces of the dies are grooved to accommodate the rib or ribs on the gripping elements, these grooves being for the most part at least as deep as the ribs are high. Thus the crimping is done without impairing the stiffening eifect of the rib or ribs. However, added tightness of the junction is obtained by decreasing the depth of a portion of the groove in the rolling tool to about half the height of the rib. When the dies operate to crimp a clip about a wire, the end portions of the rib which meet at the top of the wire are partly mashed by the shallow portion of the groove in the rolling tool. This presses the adjacent portions of the clip strongly against the wire and compacts it if the wire is of the stranded variety. The rib reduces the tendency to relax after the pressure is relieved.

For a more complete understanding of the invention, reference may be had to the following description of certain embodiments thereof, and to the drawing, of which:

Figure 1 is a fragmentary elevational view of dies embodying the invention, about to crimp the clip portion of a connector member;

2,878,854 Patented Mar. 24, 1959 Figure 2 is a similar view of the dies after the clip has been partially crimped;

Figure 3 is a section on the line 3-3 of Figure 1;

Figure 4 is a section on the line 4-4 of Figure 1;.

Figure 5 is a fragmentary elevational view of dies of a modified form about to crimp the clip portion of a connector member;

Figure 6 is a similar view of the dies, shown in Figure 5 after the clip has been partially crimped;

Figure 7 is a section on the line 7-7 of Figure 5;

Figure 8 is a section on the line 88 of Figure 5;

Figure 9 is an elevational view of the dies shown in Figures 1 and 2 at the completion of the crimping stroke;

Figure 10 is an elevational view of the dies shown in Figures 5 and 6 at the completion of the crimping stroke;

Figure 11 is a plan view of a connector member with its clip portion crimped on a wire; and

Figure 12 is a plan view of a connector member crimped to a wire which enters from a side of the member.

A set of crimping dies for crimping the clip portion of a terminal or connector member to a wire is shown in Figures 1, 2 and 9. The lower die or anvil 20 has a narrow seat 22 which is cylindrically dished or recessed to be fitted by a portion of a U-shaped clip 24 of a terminal member or connector member 26. The member 26 conventionally shown in Figure 3 has a clip portion 24 which includes pointed fingers projecting in opposite directions from the longitudinal axis of the member and bent into an open loop or U-shape to receive a wire 28 about which the fingers are to be crimped. The clip 24 is formed with a rib 30 which extends at right angles to the axis of the member so as to stiffen the fingers of the clip 24 mechanically. The rib 30 is made by indenting a groove in the inner face of the clip, causing the rib 30 to project from the outer face of the clip. The seat 220i the anvil 20 is provided with a groove 34 of sufiicient width and depth to receive and protect a portion of the rib 30 when a clip is placed on the seat of the anvil.

Above the lower die or anvil 20 is an upper die or rolling tool 40. The two dies are mounted for relative movement toward and from each other. Preferably the lower die is fixed while the upper die is vertically movable by any suitable power press as well known in the art. The lower end of the rolling tool 40 is shaped like an inverted V with a rounded apex. In other words, the lower end has two upwardly converging faces 42 and 44 which mergeinto and are connected by a cylindrical surface 46'. A continuous groove 48 is provided in the

faces

42, 46, 44 to receive the rib 30 of the clip which is to be crimped. This groove is in a common vertical plane with the groove 34 in the lower die so that when the lower portion of the rib 30 of a clip is seated in the groove 34, the upper portions of the rib will progressively enter the groove 48 as the clip is being curled or crimped by downward movement of the upper die. When the upper die descends, the fingers of the clip are curled inward until the clip assumes a cylindrical or tubular form as indicated in Figure 2. Since the rib 30 rides in the

grooves

34 and 48, it is not flattened by the pressure thus far exerted in the crimping operation.

According to the present invention, the midportion 50 of the groove 48, that is, some of the groove 48 which is in the rounded surface 46, is of less depth than the remainder of the groove, the depth of this portion of the groove being less than the height of the rib 30. At the apex of the active surface of the upper die the groove 50 may have a depth equal to about half the height of the rib 30 and may also be somewhat narrower than the rib. After the upper die presses down form, it continues its downward movement to press the clip tightly on the wireJP; If the cross-sectional area of the wire 28 is less than that of the inside of the clip when the latter is curled to the tubular form indicated in Figure 2, portions of the clip "will overflow the sides of the narrow anvil '20 as indicated in Figure 9 so that the wire will be tightly confined and squeezed within the clip. In this pressing operation the'variation in depth of the groove 48 is of special significance. The deep parts of the groove in the faces 42 and 44 protect the corresponding portions of the rib from being flattened. The shallower portion .of the groove, however, has the effect of partially flattening and narrowing the portions 7 of the rib adjacent to the. line where the fingers'of the clip 24 meet when the clip is crimped, as indicated in Figure 11. Thus the top of the clip is heavily pressed on the wire'28 but the'rib on the sides and bottom of.

the clip is left with its full height to stiffen the clip and thus to minimize relaxation thereof when the pressure of the dies is relieved. The almostcrushing pressure exerted by the rolling tool 40 in the process of partially flattening a portion of the rib at the top of the clip tends to compact the wire if it is of the stranded variety and ensures a tight mutual .engagement between the wire and clip which has a very low resistance comparing favorably with that of a welded connection.

Figures 5 to 8 and 10 illustrate a'pair of dies which operate on a similar principle but are designed to crimp the clip portion of an electric terminal or connector member to a wire which comes in from the side of the member instead of being in line with the axis thereof. Figure 12 shows a connector member of this type having a clip portion 62 adapted to be crimped about a wire 64. The clip 62 is bent into an open loop, as indicated in Figure 5, including a portion 66 in the form of a shallow trough and an upstanding portionadapted to be curled over in the crimping operation to surround a wire 64 laid in the trough. The upstanding portion may consist of one or more fingers 68, two being shown in Figures 7 and 12. To stiffen the fingers 68, a rib 70 is formed in each to project from the. outersurface thereof. The ribs are made by indenting grooves in the inner surface of the clip, the grooves and ridges extending lengthwise of the fingers 68 so that when the clip is crimped about a wire, each rib will encircle the wire as indicated in Figures 6 and 10.

To crimp the clip 62, two dies 72 and 74 are employed. The lower die or anvil 72 ispreferably fixed and has a hollowed seat 76 in its top to support the trough portion of the clip 62. The upper die or rolling tool 74 is V mounted to move up and down over the anvil 72. This die has a recess 80 therein with an inner surface having a-portion 82 like an inverted trough directly above the anvil 72. The seat 76 has grooves 84 to receive part of the ribs'70, and the recess in the upper die is grooved as at 86 to receive other-parts of the ribs 70, the grooves in the two dies being disposed in common vertical planes for this purpose. These grooves are at least as deep as the ribs 70 are high, except that the grooves 86 each have a portion 88 which is shallower and narrower so that when the final pressure comes on the clip, the end portion of each rib 70 will be partially flattened and narrowed and the pressure of the upper die will be transmitted to the wire to consolidate it if it is of the stranded type. The upper die is so arranged with reference to the anvil that the vertical wall 90 of the recess is "offset from the side 92 of the. anvil as indicated in'Figures 6 and 10. This is to provide space into which some of the clip can overflow if the wire 28 is not large enough to fill the tubular cavity formed when the clip has been crimped or curled to the tubular form shown in Figure 6." Further descent of theupper diesqueezes the clip tightly against the wire 28 as indicated in Figure 10.

'Theribs70 are preserved, except for the end portion of each, to maintain the stiffness of the clip.

die, the lower end'of said upper die having two upwardly converging faces merging into a rounded connecting face,

said seat and said faces having therein portions of a groove disposed in a vertical plane, the portion of the groove in the rounded face having a lesser depth than the other portions.

2. Apparatus for crimping about a wire a sheet metal clip having a rib embossed thereon and arranged to encircle the wire when the clip has been crimped thereon, said apparatus comprising a lower die with a seat'to support the clip, and an upper die having at its lower end two upwardly converging faces and a rounded surface connecting said faces, said seat and said faces having therein portions of a groove arranged to receive said rib, said rounded surface having a groove therein connecting the grooves in said faces but of a lesser depth thanthat of the said grooves.

References Cited in the file of this patent UNITED STATES PATENTS 676,292 Wittel June 11, 1901 1,836,497 Phelps Dec. 15, 1931 1,870,364 Jones Aug. 9, 1932 2,335,414 Hinrichs Nov. 30, 1943 2,716,275 'Matthysse Aug. 30, 1955 2,799,191 Barnes July 16, 1957