US2537820A

US2537820A - Attachment plug

Info

Publication number: US2537820A
Application number: US640921A
Authority: US
Inventors: James E Flood
Original assignee: Plastic Wire and Cable Corp
Current assignee: Plastic Wire and Cable Corp
Priority date: 1946-01-12
Filing date: 1946-01-12
Publication date: 1951-01-09
Anticipated expiration: 1968-01-09

Description

Jan. 9, 1951 J. E. FLOOD 2,537,820

ATTACHMENT PLUG Filed Jan. 12, 1946 INVENTOR Jamey ET FZaad BY *M ATTORNEYS Patented Jan. 9, 1951 ATTACHMENT PLUG James E. Flood, Norwich, Conn, assignor to The Plastic Wire & Cable Corporation, Norwich, Conn, a corporation of Connecticut Application January 12, 1946, Serial No. 640,921

2 Claims.

This invention relates to electrical plugs such as are attached to appliance and extension cords to be detachably connected to plug-receptacles.

An object of this invention is to provide an attachment plug which is economical to make and assemble with the wire connected contact blades and yet in which, when assembled, the anchored ends of the blades are permanently secured in the plug body against removal in any manner except by the destruction of the body of the plug. Heretofore, in plugs of this type in which spaced blade-receiving passages pass through the plug and converge and merge with the cord-receiving cavity at the opposite end of the plug it has been the practice to connect the blades to the conductors, spread the end of the plug having the cordreceiving cavity until the cord-receiving cavity is in substantial alignment with the blade-receiving passages and then draw the assembled blades and conductors in from the back of the plug through the passages into position with the blades projecting from the front of the plug. This has been an expensive operation and requires a good quality of rubber in the plug body to permit the extension thereof. Many times in the assembling operation the end of the insulation on the conductor engages the edge of the plug body and is stripped back unless precautions are taken to protect this end.

The present invention overcomes these diniculties by making the body of flexible material and providing the usual integral solid central portion between the blade-receiving passages of the body with a bore of a diameter to receive the conductor, which bore is preferably in a line with the conductor-receiving aperture at the base of the plug body. The bore is connected with the bladereceiving passages by slits passing through the central core.

When the plug is assembled according to the present invention the conductor is passed through the cord-receiving aperture and the bore in the central core. The contact blades are attached to the wires of the conductor and the connected blades are then withdrawn into the plug with the blades held and guided by the blade-receiving passages and the wires passing through the slits in the central core until the wires have reached the conductor-receiving cavity and the blades are in anchored position. Thereafter, the bore in the central portion is plugged up with an elongate filler which extends for substantially the full length of the central core and the slits connecting the bore to the passageways are permanently 2 I sealed, thus providing a substantially rigid integral central core for holding the blades in the passageways against removal therefrom without destruction of the body of the plug.

A feature of thepresent invention resides in the arrangement wherein the conductor and blades may be assembled with the plug without in any way distorting the body of the plug, thus permitting less resilient material to be used.

Another feature of the invention resides in the making of the filler of a different material or of a material of contrasting color to serve as identifying means for the plug or circuit in which the plug is employed.

Other features and advantages of the invention will be apparent from the specification and claims when considered in connection with the drawings in which:

Figure 1 shows a sectional view taken along line l'l of Fig. 2.

Fig. 2 shows an end view of the plug body.

Fig. 3 shows a sectional view taken along line 3-3 of Fig. 4.

Fig. 4 is an end view of the plug body with the blades in place and the central bore and slits closed.

Fig. 5 shows a view of the blades and plug body and filler or closure in position to be assembled in the plug body.

As shown in the drawings, the plug body In of flexible material, such as rubber, synthetic rubber, polyvinyl chloride and the like synthetic resins or acetates, has a conductor-receiving aperture ll formed at the back end thereof. This opens into a conductor-receiving cavity l2 which has a pair of blade-receiving slots 0r passages l3.

extending therefrom to the forward end of the plug on opposite sides of an integral central core M. The outer walls Ma of the central core form one wall of each 'of the passages 13. The walls Ma are provided with means for cooperating with the blade to anchor the blades in the passage. While this means may vary in form it is herein illustrated as a notch l5 formed in the wall and providing an abutment l5a.

As is shown in Figs. 1 and 2. the central core of the plug has a bore it extending therethrough. The bore is preferably in line with and of the same shape as the conductor-receiving aperture at the other end of the plug although it may vary in size and shape as required. The aperture and bore form a passage through which the conductor may be readily passed without substantial distortion of the plugand into a position in which the blades may be attached thereto as will be described.

The central core on each side of the bore is provided with a slit H which extends from the bore and intersects the Wall 54a. of the passage.

The conductor may have any type of insulation l9 thereon and is provided with two insulated wires 2!! connected to the contact blades El which project from the front face of the plug for insertion into the usual plug-receptacle.

The blades are anchored in the blade-receiving passages by tangs 22 lanced therefrom and projecting rearwardly so as to engage the abutment ifia when the blades are anchored in position. The inner ends of the blades are bent inwardly as shown at 210, and bear against the walls of the passage to assist the tangs in holding the blade against movement in either direction.

After the blades and conductor have been assembled with the plug a filler member 23 having the shape and substantially the length of the bore in the central core is inser ed and permanently secured therein. This filler closes the opening at the front of the plug and prevents accidental passage of foreign matter into the body and since it extends fo substantially the full length of the central core reenforces the blade-receiving passages and holds the portion of the wall Mahaving the blade anchoring means against inward displacement which might release the tang. The slits are also permanently secured together, thus forming a substantially rigid central core which holds the blades in anchored relation against separation without destruction of the plug .body.

The filler member may be in the form of a rod or plug or it may be a plastic mass which will undergo a phase change and harden in the bore. It may be made of the same material as the body or of any compatible material and may be permanently secured therein and the slits permanently sealed by suitable cements or adhesives. If the filler member is made of the same material as the body it can be dipped into a solvent therefor and the walls of the bore coated with the solvent, so that when it is inserted into the bore, the surfaces produced thereon by the solvent will cause the filler and central bore to become a single unit. The solvent may also be applied to the walls of the slits to soften them so that when pressed together they will merge and form the central core into a single unit.

Various pigments or colors may be incorporated in the material of the filler member and the exposed contrasting colors of the body and the member may serve as identification means for the plug or for the circuit in which the plug is used.

The plug of the present invention has the advantage of being provided with completely preformed blade-receiving passages and anchoring means for supporting the blades While the filler member is being inserted and the slits sealed to form the unitary central core for permanently securingthe blades to the plug.

'If desired, the end of the insulation l9 may be coated with an adhesive or bonding medium so that it may be secured to the plug and held against stripping.

In assembling the plug of the present invention the conductor is fed through the conductor-receiving aperture H and through the bore It to the position shown in Fig. 5. The aperture and bore are preferably of sufiicient size as to permit the conductor M3 to pass without danger of the inserted into the bore.

insulation l9 being stripped back. The ends of the wires are secured to the blades by soldering or any other suitable means and the blades and conductor are withdrawn into the plug with the conductor disposed in the bore and the blades being located in the blade-receiving passages and the wires passing through the slits in the central core. The assembled conductor and blades are drawn to the position in Fig. 3, wherein the wires are located in the conductor-receiving cavity I2 and the blades are in anchored position with the tangs 22 in engagement with the shoulder Hid.

The surfaces of the bore and filler member are then rendered adhesive and the member is The walls of the slits in the central core are rendered adhesive and the whole central core permanently united together by pressure exerted on the walls. It will be seen that the filler extending for substantially the length of the core backs up the thin section of the central core between the passageway and the bore and holds the anchoring means in position.

With the plug of the present invention the assembling operation can be carried out without requiring that the body of the plug be extended. Hence, a less resilient and flexible material may be used in place of a highly resilient material necessary when the plug was stretched or deformed as heretofore. Furthermore, the slits of the present invention not only permit the wires to move into the cavity as the blades are pulled into position in the blade-receiving passages but also permit the anchoring tangs to readily move into the notches without tearing or damaging the Walls of the slot.

The blades will be held in their preformed passages by the preformed anchoring means therein and may not be removed without destroying the body of the plug.

Variations and modifications may be made within the scope of this invention and portions of the improvements may be used without others.

I claim;

1. An attachment plug having a body of fiexi ble material provided with blade-receiving and anchoring passages therein on each side of a central core and a conductor-receiving aperture merging with the inner ends of said passages; and a conductor disposed in the aperture and having blades provided with anchoring tangs connected thereto and anchored in the passages in the body, said core having a slit ending in said passages and having a recess facing each respective passage; a filler recess located intermediate the ends of said slit; and a separate filler member corresponding in shape to said filler recess for insertion in said filler recess after assembly of plug, blades and attached conductors, said slit having walls which may be resiliently urged apart to facilitate the passage of the conductor and its wires and attached contact blades and anchoring tangs into the body from the front thereof during assembly when the body is flexed to cause the slit to open, and said recess cooperating with and being engaged by said anchoring tangs on the blades to anchor the blades in the passages.

2. The invention as defined in claim 1, wherein adhering means is applied to the filler member and recess therefor to seal the filler member in the recess permanently.

JAMES E. FLOOD.

(References on following page) REFERENCES CITED Number The following references are of record in the 2,094,046 file of this patent: UNITED STATES PATENTS 212971336 Number Name Date 2,308,324 1,824,657 Coldwell Sept. 22, 1931 2,312, 1,871,278 Powell Aug. 9, 1932 1,917,638 Dieckmann July 11, 1933 1,956,020 Gilbert Apr. 24, 1934 10 Number 2,025,189 Yanchenko Dec. 24, 1935 115,602 2,053,060 Becket Sept. 1, 1936 6 Name Date. Short Sept. 28, 1937 Andre Sept. 26, 1939 Chirelstein Nov. 28, 1939 White Sept. 29, 1942 Benander Jan. 12, 1943 Brownstein Mar. 2, 1943 FOREIGN PATENTS Country Date Switzerland Apr. 28, 1924 Certificate of Correction Patent No. 2,537,820 January 9, 1951 JAMES E. FLOOD It is hereby certified that error appears in the printed specification of the above numbered patent requiring correction as follows:

Column 3, line 6, after the word conductor insert 18; column 4, line 9, after position insert shown; column 6, line 11, list of references cited, for Apr. 28, 1924 read July 1, L926 and that the said Letters Patent should be read as corrected above, so that the same may conform to the record of the case in the Patent Oflice.

Signed and sealed this 13th day of March, A. D. 1951.

THOMAS F. MURPHY,

Assistant Commissioner of Patents.