Compression connector for electrical conductors

[57] ABSTRACT

The compression connector has a body with a conductor receiving recess opening outwardly laterally of the body and defined by spaced side walls extending endwise of the body. The outer edge of one side wall has an integral tab. A longitudinal groove in the side wall at the inner edge of the tab reduces the thickness of the wall to provide a hinge-like connection such that the tab can be swung inwardly into the open side of the recess and into engagement with a conductor in the recess so as to close the open side of and partially fill the recess around the conductor. The side walls and tab can be distorted into tight embracing relation to the conductor by die crimping forces applied toward the base of the recess. Longitudinal slots are provided in the body and open laterally into the bottom of the recess and slope outwardly from each other in a direction away from the base of the recess. The connector, with a given size recess, can connect to conductors throughout a wide range of diameters.

Claims, 6 Drawing Figures

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PATENTEDOEC25!O73

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3,781,459

COMPRESSION CONNECTOR FOR ELECTRICAL CONDUCTORS

BACKGROUND OF INVENTION

1. Field of Invention

Crimp connectors for bare conductors.

2. Description of Prior Art

Compressible electrical connectors of the general type herein described are well known in the art. For example, in U.S. Pat. No. 2,707,775 to Hoffman et al., issued May 3, 1955, there is shown an electrical connector for connecting a takeoff wire to a power line cable. This connector has a body with conductor-receiving recesses at its opposite edges. In one of the recesses the body is provided with a tab which can be bent manually to hold the conductor in the recess temporarily until the connector body has been crimped sufficiently to firmly embrace and grip the conductor.

In the patent to Toedtman, U.S. Pat. No. 3,156,764, issued Nov. 10, 1964, a modification of a similar connector is illustrated in which tabs are provided for both recesses and are chosen so that, upon crimping, each can enter the open sides of its associated recess in which a conductor has been placed and become part of the closure of the open side of the recess or the partial filler therefor, depending upon the diameter of the conductor. The connector in Toedtman is further refined by providing longitudinal grooves in the walls of the recess so as to render them more readily conformable to the surface contour of the conductor as the body is crimped thereabout.

The patent to Eldridge, Jr., U.S. Pat. No. 3,235,654, issued Feb. 15, 1966, discloses a compression connector similar to that in Hoffman.

In the Eldridge patent, one arm of each conductor receiving recess is provided with a tab more substantial than that shown in Hoffman. The tabs are designed to be folded into the open side of the recesses into contact with conductors therein so that, upon crimping of the body, each tab, combined with the walls of its associated recess, firmly grips the conductor therein and holds it seated in the base of the associated recess, fully embraced by the metal of the recess wall and tab. Also, in Eldridge, the tab functions for partially filling the recess so that the body can be crimped into firm embracing relationship with a conductor of small diameter, and also functions so that the tab merely closes the outer side of the recess for holding a conductor of much larger diameter.

The patent to Zemels, U.S. Pat. No. 3,322,888, issued May 30, 1967 discloses a connector for like purposes. In the Zemel’s structure, the connector body is provided at opposite edges with parallel conductor receiving recesses, which extend longitudinally of the body, and with grooves which are in opposite faces of the body and are disposed in a direction inwardly toward the midportion of the body from the bases of the conductor receiving recesses. As a refinement, the recesses are of different sizes for normally accommodating conductors of different diameters and the grooves are somewhat nearer to the bottom of the smaller recess than to the bottom of the larger recess. This is said to balance the bending and compressibility of the side walls of the recesses into their proper relations to the associated conductors.

All of these prior structures function generally on the basis of bending the side walls of a conductor-receiving recess inwardly toward each other transversely of the recess and turning them partly toward the midportion of the cross section of the body. In general, the bottoms of the recesses are such that they are engaged by the conductors, so that each conductor is under compression initially against the bottom of its associated recess and remains so during crimping and in final installed position in the crimped connector.

In the above Toedtman patent, this relation was maintained even though the bottoms of the recesses were defined by alternate longitudinal grooves and ribs which could distort to a certain degree. However, the conductor was not firmly embraced throughout the extent of its periphery, but was engaged at successive spaced locations by the inward edges of the ribs.

SUMMARY OF INVENTION

The present connector is one which is adapted to connect conductors throughout a greater range of sizes than do prior connectors. This is made possible by the configuration of the cross section of the body so that the sizes of the conductors themselves control the particular movement of the side walls of the recesses during crimping of the connector so that the walls firmly envelope the conductor which controls their movement. With conductors of maximum size, the walls move outwardly from each other and toward the median plane of the body under the applied crimping force, and with small diameter conductors the recess walls move inwardly toward each other and toward the median plane. The result is that, regardless of the size of the conductor, it is tightly embraced by the crimped body throughout the major portion of its periphery so as to assure full and firm contact for conduction of electricity and ample grip to prevent axial slipping of the conductors through the connector. This phenomenon results primarily from the provision in the body of longitudinal voids or grooves so related to the base of the conductor receiving recesses that they enable the conductor to control the wall movements during crimping. Further, a tab is provided which is so arranged that, in the case of a large size conductor, basically it wraps partially around the outer surface of the conductor and acts as recess closure or holder to constrain the conductor from radial movement out of its associated recess, but, in the case of a smaller conductor, it serves as a recess reducer which, upon crimping and partial collapse of the body, embraces the conductor to a greater extent circumferentially and passes between the conductor and the base of the associated recess so as to reduce the size of the recess and improve the bottom and side relationship of the recess walls with the conductor.

Generally, two grooves are provided for each recess and they open into the base of the recess at a common location at the midportion of the base, and diverge from each other away from the base inwardly of the body.

Various specific objects and advantages will become apparent from the following description wherein reference is made to the drawing.

DESCRIPTION OF THE DRAWING

FIG. 1 is a perspective view of a compressible connector embodying the principles of the present invention;

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FIG. 2 is an enlarged end view of the connector illustrated in FIG. 1, showing in more detail the configuration of the connector;

FIG. 3 is an end view of the connector showing it in crimped condition and connecting a small size conductor to a large size conductor;

FIG. 4 is a view similar to FIG. 3 showing a connector connecting two small size conductors;

FIG. 5 is a view similar to FIG. 3, showing the connector when connecting two maximum size conductors; and

FIG. 6 is a view similar to FIG. 2 showing a modified form of the connector.

Referring to the drawing, the compressible connector, indicated generally at 1, comprises a body 2 of metal of the proper workability and hardness to form effective mechanical connection and an ample electrical connection between the body and conductors connected thereby. The metal may be that commonly employed in crimp type connectors. As illustrative, the material may be ECO aluminum having a hardness of RH equal to or less than 20, though other materials may be employed, depending upon the particular field of use.

The body 2 is provided at its opposite lateral edges with conductor receiving recesses 3 which open outwardly edgewise of the body and extend in parallel relation to each other endwise thereof. The sides of the recess 3 are defined by two arms or side wall portions 4 and 5 which are integral with the body and which can be distorted inwardly toward each other and toward the midportion of the body by suitable crimping pressure applied in a direction normal to the bottoms of the recesses 3 by suitable hand or power operated crimping dies.

At least one of the arms, such for example, the arm 4, is provided with a tab 7 which is preferably curvilinear on its inner face so as to neatly engage in snug relationship the outer periphery of the maximum size cable to be gripped in its associated recess. The tab 7 is hingedly connected to the outer edge of the arm 4 so that it can easily be swung inwardly into the open side of its associated recess and toward the midportion of the body 2 to close the open outer side of its recess 3. Preferably, the tab 7 is such width edgewise of the body 2 and so shaped that its outer edge, indicated at 8, upon swinging of the tab 7 inwardly into closing relation to its recess 3, passes along the inside of the arm 5 and is guided thereby into firm contact and partially embracing relationship to a maximum size conductor in the recess. In such an instance, the tab 7 forms a closure for the open side of the recess 3. In the case of a smaller diameter conductor, the tab 7 continues farther into the recess 3, its edge 8 following along the inner surface of the arm 5 until it embraces the conductor to a greater circumferential extent and thereby serves as a partial filler for the recess to the extent necessary to cause the smaller conductor to be firmly embraced about its circumference by the coaction of the arms 4 and 5 and the tab 7.

In order to assure the proper swinging of each tab 7 into closing relation into the open side of its associated recess 3 under pressure of the crimping dies, the body 2 is provided with grooves 9. The grooves 9 extend longitudinally of the body parallel to each other and to the axis of the recesses 3 and are positioned one at the base of each tab 7 and the outer edge of the associated arm ,459

4. Each groove 9 is of sufficient depth so that the thickness of the connecting portion between the arm and tab 7, indicated at 10, is about two-fifths of the thickness of the outer edge of the arm 4 or the inner edge of the tab 7. Preferably, each groove is arranged so that, in the cross section of the body 2, its inner side wall is directly opposite the outer edge of the complementary arm 5.

In order to obtain the proper coordination of the movements of the different parts of the body when they are crimped and compressed and collapsed about a conductor within the range of the connector, regardless of whether the connector is of large or small size, suitable voids are provided in the body in a preselected relation to the base of each recess 3. Since the relation of the recesses to their associated voids is the same, only one recess and its voids is described in detail herein.

In the form illustrated in FIG. 2, the void is not only close to the bottom of the recess 3, but opens into the bottom of the recess 3. Preferably each void comprises two slots 11 which have a common open side or opening 12 into the bottom of the recess 3 at the midportion of the cross section of the recess. The slots 11 diverge from each other in a direction away from their common opening in the base of the recess and toward the midportion of the body 2. Thus a peak 13 is provided at the intersection of their adjacent side walls, the peak 13 being aligned with, and centered relative to, the opening 12 and exposed thereby. The central plane of each slot 11, extending from its open side through the midportion of its bottom wall, intersects the face of the body 2 toward which it slopes at or close to the lateral midportion of that face.

The example of the connector illustrated in FIG. 2, is one of wide applicability and is drawn to scale, the width between the outermost edges of the tabs 7 being 2.154 inches and the thickness being 0.875 inches, and the slots 11 diverge at an included angle of 120°.

Due to the slots 11, movement of the arms 4 and 5 of the recess 3 for conforming to conductors of different diameters during crimping is controlled by the conductors themselves.

For example, as illustrated in FIGS. 3 and 4, if a conductor Ci has a diameter at the lower limit of the range, the movement of the parts of the connector, when crimping pressure is exerted by the crimping dies in a direction edgewise of the body 2 toward the bases of the recesses 3, causes the tab 7 of the recess carrying the small conductor to swing inwardly about the hinge portion 10. The outer edge 8 of the tab enters the recess 3 and follows along the inner surface of the arm 5 until the outer portion of the tab 7 passes partway around the conductor Ci and the edge 8 lies between the bottom of the recess 3 and the conductor C,. Concurrently, the arms 4 and 5 move inwardly toward each other and concurrently toward the midportion of the body 2, the entire body 2 being compressed and reduced in overall dimension edgewise and caused to bulge laterally in the direction generally transversely of the recess 3.

On the other hand, as illustrated in FIGS. 3 and 5, if a conductor C_t of the larger size near the upper limit of the range is connected, the tab 7 then moves into the recess 3, its outer edge 8 being guided by and along the inner surface of the arm 5. When in the recess 3, the tab 7 is compressed across its width at the arms 4 and

3,781,459 which, due to the force of the dies, move toward the midportion of the body 2. As the tab 7 is being compressed between the arms 4 and 5, it first forms, in effect, a closure of the outer open side of the recess 3. During this compression, the body also is compressed toward its midportion to a greater degree than in the case of the smaller conductor. This is due to the fact that to a large extent the grooves 11 permit the arms 4 and 5 to be bent outwardly away from each other by the conductor C₂ as it is initially seated against the bottom wall of the recess and then to migrate inwardly toward the midportion of the body 2. The combined forces of the crimping dies on the tab 7 are transferred to the large diameter conductor and thereby force it inwardly during this movement, thus first spreading the arms 4 and 5 as the tab enters therebetween until the inner surface of the conductor C₂ strikes the peak 13 and is arrested. Thereupon continued application of the crimping forces causes the walls to compress about the conductor and the tab so that together they firmly embrace the conductor C₂ and provide a first physical connection therewith.

On the other hand, in case of the small conductor C_1;the recess is ample to accommodate both the conductor and the tab 7 so that upon the application of the crimping forces in a direction toward the bottom of the recesses 3, the tab 7 readily enters in between the arms 4 and 5 with its outer edge 8 travelling along the inner surface of the arm 5 until its outer edge 8 passes around and between the smaller conductor and the bottom of the recess 3 until it strikes the peak 13, after which the compression of the body 2 and the tab 7 continue until the conductor Cj is firmly embraced about substantially its entire circumference and physically connected.

Thus the arrangement of parts is such that the size of the conductor controls the movement of the tab 7, arms 4 and 5, and compression of the body 2 and provides the proper connection. As mentioned, with the large conductors, the slots 11 open up at their open sides and the arms 4 and 5 move outwardly initially until the larger conductor seats against the peak 13, whereupon the arms begin moving inwardly toward each other by partial closing of the open sides of the slots 11 to embrace the larger conductor and close the open side of the recess 3 by the tab 7.

In the case of the smaller conductor, the crimping pressure tends to cause the arms 4 and 5 to move inwardly, due to the closure and collapse of the slots 11, especially at their open sides. The arms 4 and 5 continue to move inwardly as the tab 7 bends and embraces the smaller conductor.

It is to be noted that, in the connected condition, the axis of the smaller conductor Cj is substantially the same distance from the longitudinal axis of the midportion of the body 2 as is the axis of the larger conductor C₂, even though the inner surface of the larger conductor C₂ is nearer to the axis of the body 2 than is the inner surface of the small conductor Cp

The present compressible connector, as mentioned, is one capable of connecting conductors through a wide range of sizes. The direction of movement of the recess arms is self-adjusting to the size of the conductor so as to provide an effective grip and proper centralization of the conductor in the conductor receiving recess. To this end, the arms of the recess move outwardly away from each other and concurrently toward a me6 dian plane through the connector body and normal to the lines of force in case of larger conductors and move inwardly relative to each other and also toward the median plane in the case of smaller conductors. The tab, in the case of a large conductor, acts as a closure for the open side of the conductor receiving recess, and in the case of smaller conductors, it acts as a combined wrap-around filler and closure which first embraces the smaller conductor and centers it in the recess and then proceeds to cooperate with the crimped arms of the recess to bind the conductor firmly in the recess as well as close the open side of the recess.

The broken lines in FIGS. 3 and 5 show dimensional changes and spacing of cables.

In FIG. 6, a modification is disclosed in which the voids for the recesses are single slots 14, instead of two slots 11, respectively. The connector is otherwise the same as that described in FIGS. 1 through 5. It is to be noted that the lower slot 14, from its inner open side to its bottom is biased relative to the edgewise dimensions of the connector so as to slope, from its open side to its bottom, outwardly toward the face of the connector to which the tab supporting arm 15 is attached. The upper slot 14, from its inner open side to its bottom is also biased from its open side to its bottom outwardly but away from the face of the connector to which the upper tab supporting arm 15 is attached. This connector also can connect conductors of different sizes effectively, but is not readily adaptable as that shown in FIGS. 1 through 5.