US2781498A - Retaining means for electrical plug and receptacle assemblies - Google Patents

Description

Feb. 12, 1957 MALY 2,781,498

C. M. RETAINING MEANS FOR ELECTRICAL PLUG AND RECEPTACLE ASSEMBLIES Filed Nov. 19, 1953 3 Sheets-Sheet l INVENTOR (741/0? M/Valq 5/3 ATTORNEY Feb. 12, 1957 2,781,498

C. M. MALY RETAINING NS FOR CTRICAL PLUG AND R PTACLE EMBLIES Filed Nov. 19, 1953 3 Sheets-Sheet 2 INVENTOR /I/J ATTORNEY Feb. 12, 1957 c. MQMALY 2,7

RETAINING MEANS FOR ELECTRICAL PLUG AND RECEPTACLE ASSEMBLIES Filed Nov. 19, 1955 3 Sheets-Sheet 3 8 ha ATTORNEY United States Patent RETAINING MEANS FOR ELECTRICAL PLUG AND RECEPTACLE ASSEMBLIES Claude M. Maly, New York, N. Y.

Application November 19, 1953, Serial No. 393,152

9 Claims. (Cl. 339-91) This invention relates to retaining means for electrical plug and outlet or receptacle assemblies, cord connectors, taps, sockets, back-connectors, interchassis connectors, plug-in units and similar devices.

The principal object of the invention is to provide a plug and receptacle assembly which combines the advantages of industrial heavy-duty and standard convenience type assemblies of this character, and wherein the current conducting male and female contact members are relieved from any and all mechanical stresses, such stresses being assumed and carried by the novel retaining means.

A further object of the invention is to provide retaining means which render a plug and receptacle assembly positively shakeproof, prevent accidental disconnection, do not carry current, and which may be actuated by one hand without disengaging the male from the female contacts.

A still further object of the invention is to provide a plug and receptacle assembly in which the dimensions of the contacts do not differ from those of prior devices, and whose novel plug may be used in connection with standard receptacles and vice versa.

A yet further and more specific object of the invention is to provide a novel plug and receptacle assembly which will carry comparatively high currents with standard blades while supporting a substantial length of heavy connecting wire, which will resist a certain pull, and which will maintain the male and female members in conductive contact even after their initial resiliency has been lost.

The invention resides essentially in the provision of a plug-receptacle assembly having any desired contact arrangement and embodying the novel retaining means consisting of male fastening members attached to a platform which is axially slidable along the periphery of the plug, and of female fasteners contained in the receptacle. As the female fasteners are stationary while the male members are uniformly slidable in the axial direction of the plug, their engagement or disconnection is entirely independent from the function of the contacts. Each male fastener has an elongated rounded, slotted or rectangular body which is engaged through friction by a corresponding female member, or a single female fastener may be provided for retention of the male fasteners. Both the male and female members are so constructed that their separation requires a force greater than their connection, the connection being at all times of a non-locking nature.

Various additional objects, features and advantages of the novel assembly will become apparent in the course of the following detailed description of the embodiments illustrated in the accompanying drawing, and the invention will be finally pointed out in the appendedclaims.

In the drawing,

Fig. 1 is a perspective view of a preferred embodiment of the improved plug with two male fastening members;

Fig. 2 is a front view, partly in vertical section taken on line 2--2 in Fig. 3;

Fig. 3 is a top view of the plug shown in Fig. 1;

Patented Feb. 12, 1957 Fig. 4 is a side elevational view, partly in vertical section taken on line 4-4 in Fig. 3;

Fig. 5 is a horizontal section taken on line 5-5 in Fig. 2;

Fig. 6 is a plan view of the improved receptacle for the plug of Fig. l, partly in horizontal section taken on line 6-6 in Fig. 7;

Fig. 7 is an end view of the receptacle, partly in vertical section taken on line 7-7 in Fig. 6;

Fig. 8 is a vertical section of a modified male fastening member;

Fig. 9 is a vertical section of a female fastening member for the male member shown in Fig. 8;

Fig. 10 is a plan view of the female member of Fig. 9;

Fig. 11 is a side elevational view, partly in section, of another embodiment of a male fastener;

Fig. 12 is a vertical section of the female member for the fastener shown in Fig. 11;

Fig. 13 is a plan view of the female member shown in Fig. 12;

Figs. 14 and 15 are front and side views, respectively, of another form of a male fastener;

Fig. 16 is a side view, partly in section, of the plug engaging a modified receptacle with male fasteners shown in Figs. 14 and 15;

Fig. 17 is a horizontal section taken on line 17-17 in Fig. 16; and

Fig. 18 is a vertical section Fig. 17.

Referring now in more detail to the drawing, and first to Fig. 1, the plug 20 is a single piece of plastic material, such as Bakelite (trademark), molded to shape, having a platform member 21 to which the male fasteners 22 are secured. Platform member 21 has an inner opening 23 of substantially the same configuration as the exterior contour of the upper handgripping portion 24 of the plug. This contour includes four opposed circular portions 25, two opposed circular indents 26, and two opposed rectangular vertical grooves 31 which extend through the lower part 20a of the plug. An opening 27 for the passage of electrical conductors 28 (shown in dot-dash lines) is provided in the handgripping portion 24. Two keys 30 support the platform member 21 in position with respect to the plug 20 by fitting in the respective grooves 31. The lower part 20:: of the plug 20 has a detachable plate 32 held by screws 33 (see Figs. 2 and 4).

The fastening members 22 each have their upper ends provided with a shoulder 34. Their tops are upset, i. e., riveted as at 35. Slot 3511 has the cross-section of cutout 36 but is somewhat closed through the riveting 35. The cutout 36 extends through most, though not all, of the length of the male fastening member 22.

The cross-sectional shape of a male fastener 22 is shown in Fig. 5. It is circular save for the cutout 36 forming forks 37 to engage a substantially rounded interior wall 38 which serves as a stop dog for the member 22. Interior wall 38 prevents the male fastener from being extracted from the plug 20 after assembly.

Male contact members 40 are secured to the plug 20 and suitably connected to the electrical conductors 28 in a manner well known to those skilled in the art, not shown.

Curved cutouts 41 provide room for two fingers or finger tips to pull the platform member 21 upwards in order to disengage the male fasteners from the receptacle 50, shown in Figs. 6 and 7. Such disengagement could be performed by, for example, pushing with the thumb against the top 24a of handgripping portion 24 of the plug 20 while the bent index and middle fingers, inserted into the curved cutouts 41, pull the platform 21 in the opposite direction, he, toward the top surface 24a.

A receptacle for the plug 20 has the general contour taken on line 18-18 in as shown in Fig. 6, and in its preferred embodiment two diametrically opposed sockets 51 with cutouts 67 (Fig. 7). A bottom plate 52, secured to the peripheral wall of the receptacle by screws 53 prevents socket members 56 from falling out of their holes. Receptacle St has a rectangular opening 55 for each of the male contact members 40, shown in dot-dash lines. Slotted resilient socket members 56 within socket walls 57 are provided with flanges 66 received in cutouts 67. The outer diameter of each socket member 56 is somewhat smaller than the diameter of socket 51, and the inner diameter of each socket member 56 is slightly smaller than the diameter of a male .fastener 22. Different embodiments of male and female fastening members are shown in Figs. 8 to 1 5.

grooves 63 and beads 64 are so shaped as to render inser-,

tion of a male fastener 60 into the socket member possible with but a small effort, while the extraction of member 60 requires a substantial effort. The upper, or lower, or both edges of grooves 63 and beads 64 are thus slightly rounded and flattened which, however, is not readily recognizable from the drawing. The resiliency of each female fastener 65 is due to the slot 62a.

Another embodiment of the male fastener is shown in Fig. 11, wherein a fastening member has a rectangular contour (see Fig. 13) and longitudinally spaced indents 71, each defined by a pair of inclined walls. The corresponding socket 72 (see Fig. 12) houses a U-shaped spring 73 with inwardly extending projections 74 to enter the indents 71 and thus hold the male fastener in the receptacle 50. Cutout 78 in fastener 70 is similar in its shape and purpose to the cutout 36 shown in Fig. 5. Cutouts 36, 62, 78 in the respective male fasteners 22, 60, 70 may be omitted, as well as the interior wall 38 in the plug portion 200, in which case the male fasteners may be pulled out of plug 20 completely.

The free ends 75 of each spring 73 are suitably bent to engage the shoulders 76 of the socket.

The indents 71 on fastening member 79 and the angular projections 74 on spring 73 are so shaped as to make insertion of male fastener 79 into the socket 72 possible with but a small effort while rendering the extraction of fastener 70 from the socket 72 more difficult. For this purpose, the edges of each indent 71 and each projection 74 are slightly rounded and flattened which, however, is not readily recognizable in the drawing. The socket 72 has a rectangular entrance hole 77.

Figs. 16 and 17 illustrate another embodiment of the invention wherein the plug 20 is inserted into a receptacle 80 containing a female retaining member 96. The platform 21 of plug 20 carries a pair of similar male fasteners 81, 82, shown in Figs. 14- and 15. The upper ends of fastening members 81 and 82 are upset in rivet fashion, as at 83. The elongated retaining leg 84 has its lowermost endbent over to form a nose 90 consisting of portions 85 and 86, the latter having a pair of inclined surfaces 87, 88 and a pointed edge 99a therebetween. A slot 89 is provided bctweenthe portion 86 and the leg 84 of the male fastener to permit slight movement 'of the nose with respect to the leg 84. The surfaces 87 and 88 on nose portions 90 are so inclined as to make insertion of male fasteners 31 and 82 into openings past spring 96 possible with but a small effort while rendering their extraction more difficult; however, this is not readily recognizable in the drawing.

The receptacle $0, shown in Figs. l6, l7 and18, of a suitable insulating material, such as Bakelite (trademark), consists of a cup-shaped member 91 closed by a round plate 99 ofinsulating material which is secured thereto by a number of screws 93. The end .wall of cup-shaped member 91 opposite the plate 99 has an opening 94 for the electrical conductors, not shown. Plate 99 has a flat outer surface, a cylindrical portion 101? extending into the cup-shaped member 91, and a peripheral flange 98 at the free end of the cylinder 100. Cylinder has a pair of inwardly extending projections 79. Rectangular openings 95 in the plate 99 pass through the projections 79 and adjacent portions of cylinder 1G0 and flange 98 to receive the legs 84 and nose portions 99 of the male fastening members 81, 82 (see Fig. 16).

The upper side of flange 98, the periphery of the cylinder 100 and the inner side of plate 99 form a groove 192 (see Fig. 18) which seats a circumferentially disposed helical spring 96 whose ends are interlocked as at 97 (see Fig. 17). When the legs 84 of the male fasteners 81, 82 are inserted into the holes 95, the inclined walls 88 of their nose portions 99 force the expansion spring 96 radially outwardly away from the periphery of cylinder 1% between theinner surface of plate 99 and the.

upper surface of flange 98 until the peaks 90a pass the innermost part of spring 96, whereupon the spring contracts radially inwardly over the inclined surfaces 87 of the nose portions 9%) to retain the fasteners 81, 82 in the receptacle 89. When the legs 84 of the male members 81, 82 are extracted from the receptacle, the inclined surfaces 87 of their nose portions 90 cause the spring to expand, and after the peaks 90a pass its innermost portion, the spring 96 again contracts by sliding along the surfaces 88 to find its normal position between the inner surface of plate 99, periphery of cylinder 100 and the upper surface of flange 98, ready for the next entry of the male fastening members.

The plate 99 is provided with openings 101 which are somewhat larger than the cross-section of a contact member 40 (see Fig. 17).

In this embodiment, the lower part 20a of the plug 26 has a cutout'1tl3 adjacent each opening 95 to accommodate nose portions 90 of members 81, 82 when the platform member 21 with the male fasteners is slid away from the receptacle 80.

Common to all embodiments of my invention is the principle of providing male and female fastening members which insure a firm but not locking connection between the plug and receptacle in order to reserve the action of the'contact members entirely for the conduction of current. 'Ihc fastening members relieve the contact members of any and all mechanical stresses. The novel assembly may be used in household appliances, small or medium sized electrical, industrial or farm apparatus, or plug connected electrical devices in general, as well as in cable connectors, cube taps, cube adapters and the like.

I wish it to be understood that I do not desire to be limited to the exact details of construction shown and described for obvious modifications will occur to persons skilled in the art within the spirit and scope of my invention as defined in the appended claims.

1 claim:

1. In a separable plug and receptacle assembly, the combination of a plug of insulating material having a first and a second extremity, male contacts extending from said first extremity and a reduced handgripping portion adjacent said second extremity of said plug, a platform member with an opening for slidably receiving said handgripping portion of said plug and elongated fasteners parallel with and spaced from said male contacts and each having a first and a second end with said first end attached to said'platforrn member, said plug having a plurality of bores between said reduced handgripping portion and said first extremity thereof for slidably receiving said fasteners; whereby said second ends of said fasteners may be withdrawn into said plug between said first extremity and saidreduced handgripping portion thereof when said platform member is slid along said reduced handgripping portion toward said second extremity of said plug, with a receptacle of insulating material having female contacts for reception of said male contacts, a plurality of sockets for said second ends of said fasteners when said male contacts are inserted into said female contacts and said platform member is slid along said handgripping portion toward said first extremity of said plug, and retaining means in said receptacle spaced from said female contacts for releasably engaging said second ends of said fasteners.

2. The combination of claim 1, wherein said plug has a plurality of parallel grooves extending between said extremities thereof, and said platform member has a plurality of projections extending into said grooves, the distance between said extremities of said plug exceeding the length of said fasteners.

3. The combination of claim 1, wherein each of said fasteners has an elongated cutout terminating in the proximity of said second ends thereof, and stop means is provided for retaining said fasteners in said plug including a plurality of keys extending into the respective cutouts in said fasteners, and said retaining means in said receptacie includes a resilient slotted tubular member in each of said sockets anchored in said receptacle for frictionally engaging and retaining a fastener inserted therein.

4. The combination of claim 3, wherein said fasteners have a plurality of longitudinally spaced circumferential grooves in the proximity of said second ends thereof and said tubular members have a plurality of longitudinally spaced internal beads received in said grooves when said 'a." eners are inserted into said tubular members.

5. The combination of claim 1, wherein said fasteners each have a rectangular contour and a plurality of spaced angular indents transversely of the greatest dimension thereof, and said retaining means include a resilient member of U-shape inserted into each of said sockets, said resilient members each having a plurality of inwardly facing projections transversely of the greatest dimension thereof received in said indents when said fasteners are inserted into said sockets in said receptacle.

6. The combination of claim 1, wherein each of said fasteners includes a nose portion at said second end thereof, said nose portions having an edge transversely of the greatest dimension of said fasteners defined by a pair of inclined surfaces, and said retaining means is a helical spring circumferentially adjacent said sockets in said receptacle for engaging one of said inclined surfaces when said fasteners are inserted into said sockets, said bores for said fasteners in said plug terminating in enlarged cutouts at said first extremity of said plug for reception of said nose portions when said platform member with said fasteners is slid along said reduced handgripping portion toward said second extremity of said plug.

7. The combination of claim 6, wherein said receptacle includes a cup shaped body and a plate attached to the open end of said body, a substantially cylindrical portion extending from said plate into said body and an annular flange at the free end of said cylindrical portion, said spring being inserted between said plate and said flange adjacent the periphery of said cylindrical portion, with said sockets extending through said plate, said cylindrical portion and said flange.

8. In a separable plug and receptacle assembly, the combination of a plug of insulating material having a first and a second extremity, male contacts extending from said first extremity, a reduced handgripping portion adjacent said second extremity and an enlarged portion between said handgripping portion and said first extremity of said plug with a circumferential shoulder between said enlarged and said handgripping portion, a platform member having an opening for slidably receiving said handgripping portion between said shoulder and said second extremity of said plug, a pair of elongated rodlike fasteners parallel with said male contacts and each having a first and a second end, the distance between said extremities of said plug exceeding the length of said fasteners, said first ends of said fasteners being attached to said platform member adjacent two opposing sides of said handgripping portion of said plug, said enlarged portion of said plug having a pair of parallel bores between said shoulder and said first extremity thereof with said fasteners inserted into said bores and projecting with said second ends from said first extremity of said plug when said platform member is adjacent said shoulder, each of said fasteners having an elongated cutout terminating in the proximity of said second end thereof and said enlarged portion of said plug having a pair of keys extending into the respective ones of said bores therein and into said cutouts in said fasteners, with a receptacle having a cupped body portion, a plate attached to and closing the open end of said body portion, female contacts in said receptacle for reception of said male contacts when said enlarged portion of said plug is adjacent said plate, a pair of sockets in said plate for entry of said fasteners and an enlarged slotted tubular retaining member of resilient material in each of said sockets for receiving and frictionally engaging said second ends of said fasteners inserted into said sockets.

9. The combination of a plug of insulating material having a first and a second extremity, male contacts extending from said first extremity, a reduced handgripping portion adjacent said second extremity, a body portion between said reduced handgripping portion and said first extremity, and a shoulder between said body portion and said handgripping portion, with a platform member having an opening for slidably receiving said handgripping portion, and a plurality of elongated fasteners parallel with said male contacts and each having a first and a second end, said first ends of said fasteners being attached to said platform member, said body portion of said plug having a plurality of bores, one for each of said fasteners for slidably receiving said fasteners, said second. ends of said fasteners projecting from said first extremity of said plug when said platform member is adjacent said shoulder, the distance between said extremities of said plug exceeding the length of said fasteners, whereby said second ends of said fasteners may be withdrawn into said body portion when said platform member is slid away from said shoulder along said handgripping portion toward said second extremity of said plug.

References Cited in the file of this patent UNITED STATES PATENTS 949,123 Klein Feb. 15, 1910 1,322,075 Vetter Nov. 18, 1919 1,660,290 Benjamin Feb. 21, 1928 1,775,564 Goodspeed Sept. 9, 1930 1,940,844 Cassedy Dec. 26, 1933 2,005,441 Shearer June 18, 1935 2,037,562 Chirelstein Apr. 14, 1936 2,051,425 Schlums Aug. 18, 1936 2,130,424 Grant Sept. 20, 1938 2,303,483 Ludwig Dec. 1, 1942 2,448,725 Morris Sept. 7, 1948 FOREIGN PATENTS 798,431 France Mar. 10, 1936

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