US3500299A - Electrical plug and pin structure - Google Patents

Description

March v10, 1970 A. P. DE vn'o 3,500,299

ELECTRICAL PLUG AND PIN STRUCTURE Filed Feb. 29, 1968 I N VEN TOR.

ALE/5K7 A 05%70 BY M A N, VMTORNEYS United States Patent 3,500,299 ELECTRICAL PLUG AND PIN STRUCTURE Albert P. DeVito, Niles, Ill., assignor, by mesne assignments, to Conalco Metals, Inc., a corporation of Delaware Filed Feb. 29, 1968, Ser. No. 709,329 Int. Cl. H01r 9/08 U.S. Cl. 339-220 Claims ABSTRACT OF THE DISCLOSURE An electrical plug of the quick detachable type has pin structures which are metal stamping's each of which has a body of rectangular transverse cross-section closely received within a complementary hole in the plug casting. On one end of the body is a shoulder engaging a face of the casting and providing a solder lug eye. Extending from the opposite end of the body and of the casting is a contact pin. Also on such opposite end of the body is a bendable integral locking lug which is bent over from original general alignment with one edge of the body into locking opposition to the shoulder and to a portion of the casting engaged by and between the shoulder and the looking lug.

This invention relates in general to electrical connecting devices and is more particularly concerned with a new and improved stamped metal pin structure for electrical plugs.

Various connecting pin arrangements have heretofore been employed in electrical plugs of the quick-detachable type such as may be used for effecting various electrical connections with and between panel boards, electronic components, replaceable module assemblies, and the like in effecting electrical operating circuitry. Among prior devices have been pin structures molded directly into the plug castings, force fit pin inserts, cotter pin arrangements made of pin wire stock, and the like. While the cotter pin types of pin are quickly assembled, they sufier certain disadvantages in that the wire stock must be of reasonably soft material to be readily worked in the wire forming dies and the pins are thus unduly susceptible to bending out of shape in subsequent handling and manipulation by assembling tools. Further, the wire types of pin are diflicult to maintain in as straight alignment as desirable.

Accordingly, it is an important object of the present invention to provide a new and improved pin structure for electrical plugs which is economically produced as a metal stamping in an easily assembled, reliable and effectively form-retaining construction.

Another object of the invention is to provide a novel stamped metal plug-carried pin structure having new and improved means for locking it in assembly with an electrical plug casting.

A further object of the invention is to provide a new and improved bendable locking log for a structure adapted to be mounted in an electrical pin casting.

A further object of the invention is to provide a new and improved bendable locking lug for electrical plugcarried pins.

Still another object of the invention is to provide in an electrical plug, the quick-detachable type, a new and improved contact pin structure and relationship.

Other objects, features and advantages of the present invention will be readily apparent from the following detailed description of a preferred embodiment thereof taken into conjunction with the accompanying drawing, in which:

FIG. 1 is a side elevational view of an electrical plug embodying features of the invention.

Patented Mar. 10, 1970 ICC FIG. 2 is an enlarged fragmentary vertical sectional detail view taken substantially along the line II--II of FIG. 1.

FIG. 3 is a fragmentary transverse sectional detail view taken substantially along the line III--III of FIG. 2, and

FIG. 4 is a fragmentary plan view of a metal strip showing progressive steps in the die stamping of the elec: trically conductive pins embodying the invention.

An electrical plug 5 of the quick-detachable type embodying features of the invention comprises a dielectric body casting 7 carrying at least one, and desirably a plurality of electrically conductive, suitably spaced, stamped metal pins 8. While the plug body casting 7 is depicted as of the generally cylindrical type with the pins mounted in a circular array, any other preferred geometrical form may be employed in the casting and with any preferred orientation of the pins thereon. If desired, the plug 5 may have a plug-in key stem 7a projecting from its front face.

According to the present invention, each of the pin structures 8 has a body 9 of substantially quadrangular cross section having opposite end portions, longitudinal edges along the body and opposite faces between the edges. Receptive of the body 9 is a respective hole 10 (FIGS. 2 and 3) which is of complementary quadrangular transverse cross section at least throughout its length in firm engagement with the pin body 9 so that in the assembly the pin structure is maintained firmly against transverse looseness. Thereby, a contact pin 11 extending as a finger integrally from one end portion of the body 9 and substantially beyond one end face of the plug casting 7 is maintained in accurate perpendicular alignment with respect to the plug axis and accurately spaced from the companion pins for efficient joining with a receptive socket structure. Preferably the pin 11 is substantially an extension of one longitudinal edge of the body 9 and is of generally cylindrical perimeter and has a generally rounded tip 12.

Means for positively locking the pin structure 8 to the plug casting 7 against longitudinal displacement comprise fixed shoulder means on one end portion of the body 9 and bendable locking lug means on the opposite end portion of the body by and between which a portion of the plug casting 7 is firmly engaged. In the illustrated example, the fixed shoulder means comprise a shoulder 13 normal to and extending out from one of the longitudinal edges of the body 9 adjacent to the juncture of an integral solder terminal lug 14 comprising an integral extension of that end portion of the body. This terminal is preferably of eye form having for this purpose an eye hole 15 therethrough. In the assembly, the shoulder 13 engages against the backened face of the casting 7 and faces toward the opposite end portion of the pin structure. On such opposite end portion of the pin structure and adjacent to the base of the pin finger 11 is an integral locking lug 17 which is bendable into locking opposition to the shoulder 13 and to the portion of the plug casting which is engaged by and between the locking lug and the shoulder.

In an efiicient, practicable form, the locking lug 17 is formed integrally with the pin structure body 9 to be initially within the plane of the longitudinal edge of the body extending from the shoulder 13, so that assembly of the pin structure with the casting 7 can be readily effected by relative assembly movement wherein the pin finger 11 and the body 9 are received within the bore of the hole 10 from the back face of the casting. Relative assembly movement continues until the shoulder 13 contacts the back face of the casting. Then, with the butt end of the solder lug 14 resting on an anvil surface A (FIG. 1) a locking lug clenching or bending tool applied to the locking lug drives towards the anvil A, as indicated by the directional arrow T to bend the locking lug onto a shoulder 18 facing generally outwardly from within a suitable lateral recess 19 provided-for this purpose intheforward H end face of the casting 7 alongside and as an extension of or from the bore of the hole 10. Although the locking lug 17 might be-bent out of the plane of either broad face of the body 9, a satisfactory and preferred arrangement comprises bending the locking lug in the plane of the body 9 through the plane along the adjacent longitudinal edge of the body, as shown.

To facilitate bending of the locking lug 17 along a substantial arc free from abrupt bending point, and avoiding possible fracture and weakening of the locking lug, it is shaped of gradually diminishing width from its base toward its free end. Further, along its shouldering edge 20, the lug 17 is desirably of concavely arcuate shape, which is accomplished by recessing the edge of the body 9 adjacent to the base of the locking lug. Along its opposite, inner, clenching tool-receiving edge 21, the locking lug 17 is preferably convexly arcuate toward its tip and is separated from the body 9 by a notch and converges toward, or diverges from the base of the pin finger 11. This assures controlled bending of the locking lug 17 into its clenching, clamping engagement with the shoulder 18 which, as shown, is ofconvexly rounded longitudinal contour confronting the lug edge 20 and of a differential radius so as to be engageable effectively by the locking lug edge generally tangentially and substantially free from, and; with minimum danger of, fracturing the relatively rigid dielectric material of the casting 7 when the lug is bendably thrust into engagement therewith.

Manufacture of the pin structures 8 is effected economically by die stamping the same from a sheet metal blank 22 (FIG. 4) of suitably gauge strip stock. The gauge of the material is desirably about the same as the desired diameter of the pin fingers 11. Half hard brass stock has been found excellent for the purpose. In progressive die stamping, the eye holes are punched in the strip and may serve as gauging pin holes in the progress of the strip through the dies. Also punched in the strip 22 are circular holes 23 which are oriented to provide the arcuate edges in the subsequent stamping of pin structure. Thereafter, the pin structures are partially blanked, and this may be accomplished by pluralities such as five in each stroke of the dies. In this initial blanking out, the body portions 9 and the locking lug 17 are completed and the pin fingers 11 are rough blanked out. In the next stroke of the press, the five pins previously blanked out have the finger portions 11 thereof sized to the substantially cylindrical form. In the following stroke of the press, the pins are separated from the blank 22 by blanking out of the solder lugs 14, leaving characteristic openings 24 in the scrap of the blank. Thereafter, the completed pin structures may be plated, if desired, and are ready to be assembled with the casting 7 in the manner described. 7

It will be understood that modifications and variations may be effected without departing from the scope of the novel concepts of the present invention.

I claim as my invention:

1. In a structure of the character described comprising an electrically conductive stamped metal plug-carried pin:

a pin body of substantially quadrangular transverse cross section having opposite end portions, longitudinal edges along the body and opposite faces between said edges;

a contact pin finger projecting from one of the end portions of the body;

a shoulder on one end portion of the body extending .4 I beyond one of saidedges andfacingrtoward the opposite end portion; and an integral locking lug on said opposite end portion of the body normally within said one edge to enable insertion of the pin into position on a plug body by thrusting the pin through a hole in the plug body closely complementary in cross section to said pin body cross section; said locking lug being separated along an inner edge from said body by a notch, and said one longitudinal edge having a bend-facilitating recess adjacent the base of said lug whereby to facilitate bending of the lug out of and beyond said one longitudinal edge into locking opposition to said shoulder'and to a portion of the plug engaged by and between said lug and said shoulder. v 2. A structure according to claim 1, said locking lug being on said pin body adjacent the juncture of said contact pin finger with said pin body, and said notch being between said finger and said lug.

, 3. A structure according to claim 2, said finger being substantially an extension of the other of said longitudinal edges of the pin body.

4. A structure according to claim 3, said finger being sized to have a substantially cylindrical cross section.

5. A structure according to claim 1, said lug having an arcuate edge along said recess to facilitate bending of the lug.

6. A structure according to claim 1, said lug having an edge along said notch which is convexly arcuate toward the tip of the lug to facilitate bending of the lug.

7. A structure according to claim 1, said lug having a 1 concavely arcuate edge along said recess and a convexly arcuate edge along said notch whereby to facilitate bending of the lug.

8. A structure according to claim 1, said locking lug being of gradually diminishing width between said notch and said recess from the base of the lug toward the free end of the lug to avoid abrupt bending point in the bending of the lug and thereby avoiding possible fracture and weakening of the lug during bending.

9. A structure according to claim 1, including, in combination with said pin, a dielectric plug body casting having said hole in complementary firm engagement with said edges and faces of said pin body, said shoulder engaging said casting at one end of said hole, said casting having an opposite end provided with a recess alongside said hole and with a shoulder in said recess facing generally in the same'direction as said pin shoulder and engaged by said locking lug substantially without fracture of the casting at the casting shoulder.

10; A structure according to claim 9, said lug having a concavely arcuate edge confronting said casting shoulder,

and said casting shoulder being of convexly rounded contour confronting said lug edge and of a differential radius such that the lug edge engages the shoulder generally tangentially and substantially free from fracturing the material of the casting at the shoulder.

References Cited UNITED STATES PATENTS 1,716,144 6/1929 Morrison 339-215 2,316,555 4/1943 Bugg 339-215 XR 3,109,689 11/1963 Cooney.

3,241,097 3/1966 Ege.

KENNETH DOWNEY, Primary Examiner

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