US3794961A

US3794961A - Electrical twin plug

Info

Publication number: US3794961A
Application number: US00139339A
Authority: US
Inventors: J Bailey; V Lavigne
Original assignee: Switchcraft Inc
Current assignee: Switchcraft Inc
Priority date: 1971-05-03
Filing date: 1971-05-03
Publication date: 1974-02-26
Anticipated expiration: 1991-02-26

Abstract

An electrical twin plug useful in communication, patching, and for other purposes is constructed with a removable handle which is interlocked with the plug bodies and can be removed to expose the terminals within the plugs merely by pressing inwardly at the interlocking means and pulling axially. The handle and plug bodies can then be reassembled by aligning an interior boss of the handle with a recess in each plug body and pressing the two members together axially until they are interlocked. Assembly screws are thereby eliminated and a very narrow twin plug is obtained which can be mounted side by side with other plugs.

Description

[451 Feb. 26, 1974 United States Patent 1 Bailey et a].

.. 339/213 R X 339/217 5 X 339/183 X 2,753,392 7/1956 Hcbeler 3,218,603 11/1965 Sanislo..... 3,656,089 4/1972 Bailey [73] Assignee: Switchcraft, Inc., Chicago, 111.

Primary ExaminerRichard E. Moore Attorney, Agent, or Firm.1ohnston, Keil, Thomson & Shurtleff 22 Filed: May 3,1971 21 App1.No.: 139,339

[57] ABSTRACT An electrical twin plug useful in communication, patching, and for other purposes is constructed with a Related U.S. Application Data [63] Continuation-impart of Ser. No. 108,792, Jan. 22,

1971, abandoned.

removable handle which is interlocked with the plug Us. CID-"u 339/108 339/213 R 339/217 R bodies and can be removed to expose the terminals [51] .13

within the plugs merely by pressing inwardly at the in- 1 13/00 terlocking means and pulling axially. The handle and plug bodies can then be reassembled by aligning an interior boss of the handle with a recess in each plug 2 o 2 QM 1 In ,9 83 O3 1 oo 1 9 3 3 h c r a e S f o d l e i F 1 8 5 1 References Cited body and pressing the two members together axially UNITED STATES PATENTS until they are interlocked. Assembly screws are thereby eliminated and a very narrow twin plug is ob- 339/183 tained which can be mounted side by side with other 339/183 plugs 5 Claims, 14 Drawing Figures 1,819,040 Schellenger......................... 3,383,481 5/1968 Bailey et a1...

1,669,013 5/1928 Nowosielski 1,456,516 5/1923 Riecken ELECTRICAL TWIN PLUG This application is a continuation-in-part of US. application Ser. No. 108,792 filed Jan. 22, 1971, now abandoned.

BACKGROUND OF THE INVENTION ,.itxf x w or w i l i mina ssessssi s. H29 1 whether the plug is a Z-conductor or a 3-conductor plug. The portion of each plug body containing the electrical terminal or terminals is usually covered by a handle which is held in place by means of a screw. The handle can be removed by removing the screw thereby exposing the electrical terminal or terminals. This type of plug suffers from the disadvantage that it is sometimes difficult to replace the screw used in assembling the handle with the plug. In small plugs the screw is small, and it has to be aligned with the threaded portion of the plug body which is sometimes quite difficult. Very often the screw becomes displaced and frequently is lost during attempts to assemble the handle with the plug body.

Conventional twin plugs which can be taken apart for the purpose of connecting wires to terminals also suffer from the disadvantage that they are relatively wide and cannot be mounted side by side on a conventional terminal board. Narrow molded plugs are available but they cannot be taken apart for wiring purposes and reassembled. I

OBJECTS One of the objects of the present invention is to provide a new and improved type of electrical twin plug in which the handle is mechanically interlocked with the plug bodies and can be removed merely by pressing inwardly at the interlocking means and pulling the plugs axially.

Another object of the invention is to provide a new and improved type of electrical twin plug in which the handle can be assembled and interlocked with the plug bodies merely by sliding it over the two plug bodies until openings in the handle interlock with projections in the plug bodies.

A more specific object of the invention is to provide an electrical twin plug of the type described having a simple and positive interlocking means between the plugs and the handle which permits the removal of the handle and its reassembly with the plugs without the use of screws.

A further object is to provide a new and improved twin plug of the type described which is narrow in width.

Other objects and advantages of the invention will be apparent by reference to the following description in conjunction with the accompanying drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. I is a perspective view of one embodiment of a twin plug provided in accordance with the invention;

FIG. 2 is a perspective view of the twin plug of FIG. 1 in reversed position;

FIG. 3 is a perspective view of the twin plug of FIGS. 1 and 2, illustrating how the plug bodies are removed from the handle;

FIG. 4 is an exploded perspective view of the handle and other components disassembled;

FIG. 5 is a vertical sectional view of an assembled twin plug;

FIG. 6 is a horizontal sectional view of the assembled twin plug;

FIG. 7 is a vertical sectional view taken along the line 77 of FIG. 5;

FIG. 8 is a vertical sectional view taken along the line 88 of FIG. 5;

FIG. 9 is a vertical sectional view taken along the line 99 of FIG. 5;

FIG. 10 is a partial vertical section in reduced size of the handle only of said twin plug.

FIGS. 11 and 12 illustrate an alternative method of disassembling the twin plug; and

FIGS. 13 and 14 further illustrate the assembly of the twin plug.

BRIEF SUMMARY OF THE INVENTION In accordance with the invention an electrical twin plug is provided having two elongated plug bodies, one end of each of which is adapted to be inserted into an electrical jack, said plug bodies each containing at least one electrical terminal, a removable handle covering the portions of said plug bodies containing said terminals, and mechanical interlocking means between said handle and said plug bodies adapted to lock said handle in fixed relationship with said plug bodies by pressing said handle and said plug bodies together axially, and to permit unlocking and removal of said handle from the portions of sai plug bodies containing said terminals by pressing each of said plug bodies inwardly at one end.

DETAILED DESCRIPTION OF THE INVENTION Referring to FIGS. 1-5 of the drawings, a 3- conductor electrical twin plug is illustrated which con sists of two plug bodies generally shown at I and 2 and a handle generally shown at 3. One end of the plug body I has a tip rod 4 and a sleeve 5 usually made of brass or other electrically conducting material and insulated from one another by an insulating material 6 usually made of ethyl cellulose, nylon, or other electrically insulating material which can be molded. The tip rod and sleeve are normally round in cross section and are adapted to be inserted into an electrical jack. The sleeve 5 has a laterally offset portion 7 which extends rearwardly to form a generally tubular housing 8 adapted to receive an electrical conductor 9 which is connected to the inner portion 10 of the tip rod 4 by means of a screw 11. As shown, the housing 8 has an opening or cavity therein at 12, so that when the handle 3 is removed the screw 11 which connects the conductor 9 to the inner end 10 of tip rod 4 is readily accessible.

The rear end 13 of the plug body 1 is provided with internal threads 14 so that electrical conducting shield 15 of cable 16 can be inserted into the opening at the rear end of the plug body thereby electrically connecting the shield 15 to the sleeve 5 through the housing 8.

Similarly, the plug body 2 has a tip rod 17 and a sleeve 18 insulated from one another by an insulating material 19. The sleeve 18 has a laterally extending offset portion 20 which extends rearwardly to form a generally tubular housing 21 adapted to receive an electrical conductor 22 which is connected to the inner portion 23 of tip rod 17 by means of a screw 24 so that when the handle 3 is removed the screw 24 which con nects the conductor 22 to the inner end 23 of tip rod 17 is readily accessible. The rear end 25 of plug body 2 is provided with internal threads 26 so that cable 16 and its electrically conducting shield 15 can be inserted into the opening at the rear end of the plug body thereby electrically connecting the shield 15 to sleeve 18 through the housing 21.

A button 26 has an inner end 27 which is adapted to be inserted into the open end of housing 8 with an enlarged portion 28 extending outwardly. The inner end 27 contains three

recesses

29, 30 and 31 (see FIGS. and 8), any one of which is adapted to receive the end of shield and to hold said shield 15 in a fixed position against threads 14.

The handle 3 contains a hole or opening 32 which is adapted to receive a projecting portion 33 of housing 8. In a similar manner the opposite side of handle 3 contains an opening 34 adapted to receive a projecting portion 35 of housing 21 of plug body 2. By grasping the cable 16 and the button 26 between the thumb and one finger and pressing them together as shown in FIG. 3, the

projections

33 and 35 are disengaged from the

openings

32 and 34 and by pulling axially on handle 3 the latter can be removed from both

plug bodies

1 and 2 in the manner illustrated in FIG. 4 thereby disengaging the plug bodies from the handle. The wires in the plug bodies can then be removed by unscrewing the terminal screws 11 and 24. The shield 15 can be re leased by pulling outwardly on button 26.

In order to permit cross wiring, the cavities in the plug bodies should face each other in the manner shown in the drawings and to maintain them in alignment the handle 3 is provided with an upper internal boss 36 and a lower internal boss 37 (see FIGS. 8 to 10) which extend longitudinally and are received by

recesses

38 and 39 in plug bodies 1 and 2 (see FIG. 4). Optionally, for the purpose of aligning the handle 3 and for convenience in indicating a predetermined position of the handle with respect to plugs l and 2, notches 40 are made in the handle. In order to reassemble the handle with the

plug bodies

1 and 2 the handle is positioned as shown in FIG. 4 with the notched portion opposite the button 26 and with recess 38 aligned with boss 36 and recess 39 aligned with boss 37. The handle is then moved axially over the

plug bodies

1 and 2 until the

projections

33 and 35 snap into the sides of

openings

32 and 34. The ends 41 and 42 of

bosses

36 and 37 will then rest against the rear ends of the cavity openings in the

plug bodies

1 and 2. Instead of continuous bosses as shown at 41 and 42 a series of aligned round projecting bosses can be used.

Openings

43 and 44 opposite the terminal screws 1 1 and 24 make it possible to test the circuit without removing the handle.

The handle 3 is usually made of a slightly flexible polymeric plastic material so that itis somewhat resilient. It can be extruded or molded. When it is molded, the tubular passageways or the

plug bodies

1 and 2 are separated at 45 as shown in FIG. 10. If the handle is extruded, the separator 45 is normally omitted.

It should be noted that the sloped

internal surfaces

46, 47, 48 and 49 (see FIGS. 4 and 7) of handle 3 are acted upon by the two plug bodies when they are squeezed together and cause the sides of the handle 3 to bulge outwardly thereby permitting the two plug bodies to be pinched closer together to disengage the locking

members

33 and 35 from the sides of the

openings

32 and 34. To facilitate the bulging effect, the tubular sections of the handle have an open passageway between them in the area adjacent the locking means. Without this camming or wedging effect due to the configuration described, it would be necessary to compress the material of the handle which would make the disengagement of the locking means more difficult.

Another method of disassembly is illustrated in FIGS. 11 and 12. The plug is placed on edge as shown and a small screw driver 50 or other suitable instrument is inserted through opening 32 and pressed against lip 33 of housing 8 of plug body 1, forcing said lip inwardly far enough to disengage it from opening 32 and moving plug body 1 axially to prevent re-engagement. The plug is then turned over and the same procedure repeated by inserting the end of implement 50 through opening 34 and pressing inwardly against lip 35 and moving housing 21 of plug body 2 axially until lip 35 is disen gaged. The

plug bodies

1 and 2 can then be removed axially from handle 3.

To install the cables, the braided shield 15 (FIGS. 12 and 13) is folded back over the insulation and the

leads

9 and 22 are inserted through the rear of plug 2 until the

lead terminations

51 and 52 line up with the threaded tip and/or ring openings where they are secured by screws 1 1 and 24 as shown in FIG. 5. The free end of braided shield 15 (common connection) is placed in the opening at the rear of plug 1 and button 26 is inserted to hold it in place. The

plug bodies

1 and 2 are then held by the fingers of one hand and handle 3 by the fingers of the other with the bosses 36'and 37 (see FIGS. 8 and 9) aligned with recesses 38 and 39 (see FIG. 4) and the handle and plug bodies moved axially together until the

lips

33 and 35 snap into

openings

32 and 34.

While it is preferable to have interlocking means for each plug body to insure retention of both plug bodies in the handle for all uses, in some cases a single interlocking lip and opening will suffice.

It will be recognized that the same type of structure can be used in making a six-conductor twin plug where each plug body contains a tip member, a ring member and a sleeve member. Instead of having a single cable coming out of the twin plug the end button 26 can be omitted and two independent cables used. The device can also be used as a terminating plug with two end buttons 26 and no cables. The notches 40 assist in identifying the top of the plug so that the plug can be polarized. The button 26 due to its outward extension provides leverage and helps to release the plug fingers from the handle. It also serves to clamp the wire and acts as a cover to prevent the access of dirt where only one cable is used as shown in the previously described embodiment, or where the device is used as a terminating plug.

The invention is especially useful in providing an attachable plug which can be taken apart and reassembled and at the same time is relatively narrow so that two or more plugs can be mounted side by side on a switchboard.

The invention is hereby claimed as follows:

1. An electrical twin plug having two elongated plug bodies one end of each of which is adapted to be inserted into an electrical jack, said plug bodies each containing at least one electrical terminal, a removable handle covering said portions of said plug bodies containing said terminals, and mechanical interlocking means between said handle and said plug bodies adapted to lock said handle in fixed relationship with said plug bodies by pressing said handle and said plug bodies together axially and to permit unlocking and removal of said handle from the portions of said plug bodies containing said terminals by pressing inwardly at said interlocking means, said handle containing two adjoining tubular sections each of which is provided with an internal boss and a portion of each said plug body containing said terminal having a recess adjacent the periphery, said boss being received in said recess when said plug body and handle are pressed together axially.

2. A plug as claimed in claim 1 comprising a button inserted in the rear end of one of said plug bodies and projecting rearwardly from said handle, said button being adapted to hold an electrical conductor between a side of said button and an inner side of said plug body to afford an electrical connection between said plug bodies.

3. An electrical twin plug as claimed in claim I having a pair of elongated plug bodies each including an electrically conducting tip rod and sleeve electrically insulated from one another at one end, extending axially from an intermediate laterally extending offset portion and adapted to be inserted into an electrical jack,

said offset portion extending rearwardly to form a generally tubular housing, connecting means in each said tubular housing for connecting said tip rod to an electrical conductor, each said housing being formed with an opening in a wall thereof through which said connecting means is accessible, said openings facing each other, said handle having two tubular sections slidably mounted on said housings, said interlocking means between said handle and said housings including an opening and a projecting member to hold said handle in place and internal boss means in said handle interfitting with recesses in said offset portion to guide said handle with respect to said plug bodies when said twin plug is assembled.

4. A plug as claimed in claim 1 in which each of said plug bodies fits into a tubular section of said handle and said tubular sections of said handle have an open passageway between them adjacent said interlocking means to facilitate unlocking said interlocking means.

5. A plug as claimed in claim 3 in which said tubular sections have sides sloping to an open passageway between them and opposite said interlocking means, whereby when said plug bodies are pressed together at their rear ends they contact said sides causing them to bulge outwardly and permitting said plug bodies to be brought closer together, thereby facilitating the release of said interlocking means.

UNITED STATES PATENT OFFICE CERTIFICATE OF CORRECTION PATENT NO. 3,794,961

DATED February 26, 1974 INVENTOR(S) James R. Bailey and Vernon W. Lavigne It is certified that error appears in the above-identified patent and that said Letters Patent are hereby corrected as shown below:

Column 2, line 35, "sai" should read --said--.

Column 2,-line 51, after "laterally" insert --extending--.

Signed and sealed this 6th day of May 1975.

(SEAL) Attest:

C. MARSHALL DANN Commissioner of Patents and Trademarks RUTH C. MASON Attesting Officer

Claims

3. An electrical twin plug as claimed in claim 1 having a pair of elongated plug bodies each including an electrically conducting tip rod and sleeve electrically insulated from one another at one end, extending axially from an intermediate laterally extending offset portion and adapted to be inserted into an electrical jack, said offset portion extending rearwardly to form a generally tubular housing, connecting means in each said tubular housing for connecting said tip roD to an electrical conductor, each said housing being formed with an opening in a wall thereof through which said connecting means is accessible, said openings facing each other, said handle having two tubular sections slidably mounted on said housings, said interlocking means between said handle and said housings including an opening and a projecting member to hold said handle in place and internal boss means in said handle interfitting with recesses in said offset portion to guide said handle with respect to said plug bodies when said twin plug is assembled.