US3003135A - Electrical contacts - Google Patents

Description

I INVENTOR.

3,003,135 ELECTRICAL CONTACTS Richard M. Purinton, Lexington, Mass., assignor to 'Amphenol-Borg Electronics Corporation, a corporation of Delaware Filed Dec. 28, 1956, Ser. No. 631,212 2 Claims. (Cl. 339262) This invention relates to electrical connectors and has specific reference to an improved type of female contact suitable for use in single or multiple contact connectors.

It is the primary aim of the present invention to provide an improved contact which is more efficient, dependable and trouble-free than types heretofore devised; in short, a contact of design such that it is not readily distorted or damaged, even under the most adverse circumstances, and so constructed as to be capable of eflicient performance even under conditions of extreme misuse and abuse. A further aim of the invention is to provide such an improved contact which is nevertheless so designed that it is well adapted to economical mass-production methods of manufacture, and easily assembled with the other component parts of a connector.

It may be explained that while many conventional connectors of the prior art are designed to use mating contacts wherein the female portion of the contact members consists of a split sleeve arranged to receive a cylindrical contact pin, yet all of these designs heretofore commonly known or used commercially in this country have had inherent shortcomings which the present invention overcomes.

For example, such contacts are often rendered useless or ineffective by permanent spreading of the split sleeve. It follows that these prior types of contacts have required extremely close tolerances in the process of manufacture, since the insertion of an oversized pin in one of the contact sleeves will effect a permanent set in the sleeve, expanding it enough so that it Will not thereafter exert the requisite degree of frictional force on a pin of standard size. Distortion of the contact sleeves has also often been due to misalignment between the opposing contact members or to presence of dust, dirt or foreign substances which interfere with the proper insertion of the contact pin in the sleeve. These disadvantages, all too apparent in the priorart, are overcome in the present invention by the provision of a female contact comprising a split sleeve of considerable yieldability, yet provided with means to limit the expansion of the sleeve and prevent it from acquiring a permanent set."

It is a specific object of the present invention to provide a female contact sleeve characterized by a greater degree of flexing movement than ordinarily. accomplished by prior types of sleeve contacts, yet to accomplish this re sult with a construction so rugged that it is not easily damaged in service. The accomplishment of this object results in a contact capable of satisfactory operation under the most severe conditions of misuse and abuse. In addition, it allows the use of contact pins having greater tolerances as to diameter and alignment than heretofore.

In the present invention the contact may consist of a sleeve thin enough to provide any desired degree of flexing, but permanent distortion of the relatively thin resilient jaw portions of the sleeve is prevented by a protective hood, permanently mounted on the forward end of the contact sleeve and in such close relationship with the outer surfaces of the contact jaws as to limit the flexing movement thereof and to prevent any over-flexing. The jaws of the contact are further protected by a sizing ring of fixed diameter on the end portion of said hood, the sizing ring consisting of an inwardly projecting flange defining a mouth opening ofpredetermined size, coaxially disposed in front of the jaws of the contact sleeve. By

nite States Patent 6 this expedient, it is practicable to establish a precise limit as to the maximum diameter of contact pin which will be accepted in. the sleeve. Thus the combined effect of the sizing ring at the mouth of the contact and the walls of the hood surrounding the sleeve effectively prevents permanent deformation of the contact jaws of the sleeve, either by insertion of an oversized pin or by inaccuracies in angular alignment.

A preferred embodiment of the invention is illustrated in the drawings of the present specification, wherein the single figure is a longitudinal cross sectional view of a connector contact constructed in accordance with the teachings of this disclosure.

In the specific form of the invention illustrated, the contact is of generally tubular form, having three coacting component parts in permanently assembled relation. The main contact element 10 of a type designed for massproduction manufacture by automatic screw machine, with a cylindrical mounting shank 11, separated from a sleeve portion 12 by an annular shoulder 13 and circum ferential groove 14.

The rearmost end of the contact is tapered at 15 and has its end riveted into a terminal member 16 having cylindrical side walls 17 appropriately cut away at 18 to form a convenient solder pocket. The riveted end 19 of the contact extends into the soldering pocket 20, so that conductors inserted into the soldering pocket are directly fused to the main contact member '10 when molten solder is introduced into the pocket. The terminal portion 16 is of greater diameter than the intermediate shank portion 11 so that it, abuts the rear surface 21 of the dielectric member 22 in which the contact is mounted. Also, the shoulder 13 on the contact abuts the internal shoulder 23 within the contact cavity 24, so that the contact assembly is permanently secured in the contact cavity, yet is freely rotatable so that any twisting component of force which might be developed (by stretching of a twisted wire conductor, for example) is relieved without damage to the contact or wire.

The sleeve portion 12 of the contact is preferably of cylindrical form throughout its length, drilled from its leading end with a central cylindrical bore 25 and with the leading end of the contact body split at 26 to form a pair of oppositely disposed jaw members 27 and 28. These are inclined slightly inwardly with respect to each other so that the distance between the inside cylindrical surfaces at the mouth of the jaws is substantially less than the internal diameter of the sleeve at the innermost end of the bore. Preferably the bore is tapered at its mouth so that the jaws 27, 28 each have a slight outward flare 29 to insure smooth sliding engagement with a mating contact pin.

A protective hood 31 encloses the sleeve portion 12 of the contact and surrounds the jaw portions 27 and 28. The protective hood is of tubular form, and of inside diameter only a few thousandths of aninch greater than the outer diameter of the sleeve 12. In practice, the rearward tubular end of the hood is permanently secured in the groove 14 of the contact by an inwardly crimped end flange 32 which engages the groove 14 in locking relation. The leading end of the hood 31 has an inwardly extending and angularly inclined flange 33, with a central mouth aperture 34. The mouth of the hood aperture is in generally axial alignment of the central longitudinal axis of the bore of the contact body element and is spaced just forwardly of the flared end portions 29 of the jaws. The aperture 3'4 is of fixed, precalculated diameter, somewhat greater than the spacing between the forward ends of the contact jaws 27 and 28, but no greater than the maximum diameter of the bore of the sleeve.

From the above it will be apparent that the fixed dimension mouth aperture 34 will permit insertion of any contact pin of the proper size, but will prevent insertion of a contact pin suiflciently oversized to impart any permanent set to the jaws 27 and 28. Moreover, the forward portion of the hood 31 is so closely spaced with respect to each of the individual jaws that if either or both jaws are fiexed outwardly, as by a misaligned pin or foreign object, the outer surfaces of the individual jaws will come into contact with the inner surface of the hood. This will prevent flexing the individual jaws beyond their elastic limit.

With the present construction, the relatively thin jaw sections 27 and 28 may be so formed as to have adequate springiness, with the degree of yieldaoility necessary to accommodate themselves to contact pins having any reasonable variations in diameter. This eliminates any need for excessively close tolerances and assures good electrical contact with pins of any acceptable diameter. Notwithstanding this, the jaws are protected against overflexing in two ways. Damage due to insertion of an oversize pin is prevented by the fixed dimension of the mouth aperture 34-. The jaws are also protected against damage due to insertion of a badly misaligned pin by the hood 31, the inner cylindrical walls of which limit the flexing of the jaws. These features result in an improved contact Wherein the metal of the contact may be thin enough to provide a high degree of yieldability yet not so delicate as to be easily damaged. Also, the contact shank and terminal portions coact to hold the contacts securely (yet rotatably) in a dielectric which may be of integral, one piece construction. Electrically, the contact is a single piece since the conductors introduced into the solder pocket of the terminal sleeve are fused directly to the riveted end of the main contact member. It follows that the contacts of this disclosure have a high degree of efliciency, yet are simple in construction and relatively inexpensive to manufacture.

Having thus described my invention, what I claim as new and desire to secure by United States Letters Patent 1s:

1. A female contact for electrical connectors comprising, in combination, an elongated body portion of generally tubular form including a central bore entering the body from one end and forming an open ended hollow sleeve; said sleeve being split into a plurality of separate individual spring jaws in opposed relationship with respect to each other; at least one of said jaws being inclined inwardly toward the central axis of the body; with a tubular hood surrounding and enclosing the end portion of said sleeve and closely spaced with respect to the outer surfaces of said jaws to permit outward flexing of the individual jaws yet limit said flexing and prevent permanent deformation of said jaws by flexing beyond their elastic limit; said hood having a forward end portion projecting beyond the end of said jaws and supporting an inwardly directed flange defining an aperture of fixed dimension beyond the ends of said jaws; said aperture being of size greater than the distance between the aforementioned jaws and less than the size of the aforesaid bore of the sleeve, with the rearward portion of said hood extending along the sleeve portion of said contact a distance greater than the length of said jaws and being secured to said sleeve at a point remote from the ends of said jaws.

2. A female contact for electrical connectors comprising, in combination, an elongated body portion of generally tubular form including a central bore entering the body from one end and forming an open ended hollow sleeve; said sleeve being split into a plurality of separate individual spring jaws in opposed relationship with respect to each other; at least one of said jaws being inclined inwardly toward the central axis of the body; with a tubular hood surrounding and enclosing the end portion of said sleeve and closely spaced with respect to the outer surfaces of said jaws to permit outward flexing of the individual jaws yet limit said flexing and prevent permanent deformation of said jaws by flexing beyond their elastic limit; said hood having a forward end portion projecting beyond the end of said jaws and supporting an inwardly directed flange defining an aperture of fixed dimension beyond the ends of said jaws; said aperture being of size greater than the distance between the aforementioned jaws and less than the size of the aforesaid bore of the sleeve.

References Cited in the file of this patent UNITED STATES PATENTS 1,531,816 Russell Mar. 31, 1925 1,696,616 Wappler Dec. 25, 1928 1,939,361 Oppenheim Dec. 12, 1933 2,563,712 Frei et al Aug. 7, 1951 2,563,760 Uline Aug. 7, 1951 2,728,062 Klosterm-ann Dec. 20, 1955 2,783,447 Watts Feb. 26, 1957 FOREIGN PATENTS 487,606 Germany Dec. 14, 1929 479,289 Great Britain Jan. 31, 1938 662,736 Germany July 20, 1938 614,012 Great Britain Dec. 8, 1948 57,339 France Oct. 8, 1952 (Addition to 961,250)

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