US 2252454 A
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G. BENANDER 2,252,454 I v PLUG RECEPTACLE Filed May 2, 1940 Figl.
Inventor: George B. Benander,
His Attorney Patented Aug. 12, 1941 PLUG RECEPTACLE George B. Benander, Oaklawn, R. I., assignor to The Monowatt Electric Corporation, a. corporation of Connecticut Application May 2, 1940, Serial No. 332,980
The present invention relates to plug receptacles such as are used in house wiring and particularly to duplex plug receptacles of the type having T-slots whereby the receptacle is adapted to receive a contact plug or cap having either parallel or tandem blades. However, the invention is not limited thereto necessarily and may be used wherever found applicable.
The object of my invention is to provide an improved receptacle of this type which is simple in construction, capable of being manufactured and assembled at low cost, and has contacts so constructed and arranged as to make good engagement with the blades of a plug or cap, and have a long life.
For a consideration of what I believe to be novel and my invention; attention is directed to the following specification and claims appended thereto.
In the drawing, Fig. 1 is a face View of a duplex receptacle of the T-slot type embodying my invention; Fig. 2 is a face view with the cover and cross bar removed; Fig. 3 is a perspective View of the construction shown in Fig. 2 with one of the contact bars removed from the base, and Fig. 4 is a side view, partly in section.
Referring to the drawing, the receptacle comprises a body formed from suitable insulating material having a base 5 and a cover 6 attached to the base by screws which extend up through holes 1 in the base and thread into suitable openings in the cover. Base 5 has a bottom wall 8, the central portion of which is provided with transversely extending reinforcing ribs 9. At
each end, the base is provided with heads l0.
those in each head are in alignment transversely of the head. Each socket is provided with a side opening 15 in its inner transverse wall, the openings being located adjacent to the longitudinal center of the base and in line with recesses l3. This provides longitudinally spaced inwardly extending walls IS on each side of the longitudinal axis of the base which define between them side openings ll. The outer surfaces of adjacent walls 16 are straight and parallel with each other, the inner ends of the walls are rounded and the inner surfaces taper outwardly so that the walls are thicker at their bases than at their free ends.
Extending longitudinally of the base is a groove I8 having enlarged ends IS in which is located a cross bar having at its ends the ears 20 to receive screws for fastening the receptacle in an outlet box. The cross bar is held in position in the groove by cover 6. At l9 is a post for supporting the cross bar at its center.
On each side of the base is a contact bar comprising two strips 2| and 22. The central portions of the strips are U-shaped and are nested one within the other so that the U-shaped portion of each bar comprises two thicknesses of material. The ends 23 of inner strip 2| project into th longitudinalrecesses l3 to form contacts therein and each end 23 is curved longitudinally to stiffen it and to provide a curved surface for engagement with a plug prong. The ends 24 of outer bars 22 are located in the recesses l4 and have angularly bent enlarged contact ends 25 which stand at right angles to ends 23 and terminate adjacent thereto. Enlarged ends 25 are curved longitudinally and the curved surfaces stand adjacent to wall surfaces 26 of sockets II and I2.
The nested U-shaped portions of the strips are of a width to fit snugly between the adjacent surfaces of walls l6 and the ends of the sidewalls where they merge into contact ends 23 and 24 are curved to fit snugly around the curved ends of walls l6 as best shown in Fig. 3. The bottom edges of strips 2| and 22 fit over the outer ends of ribs 9 and in grooves 21 formed between ribs 9 and the adjacent surfaces of walls Hi. In the contact bars are binding screws 28, two on each side being provided in the present instance. These screws pass loosely through openings in outer strips 22 and thread into tapped openings in inner strips 2|.
The upper edges of the contact bars are flush with the top surface of base 5 and are held in place by cover 6. On the under side of cover 6 are shoulders 28 which stand behind the top edges of the contact bars as shown in Fig. 4. These shoulders cooperate with ribs 9 to hold the 7 central portions of the contact bars against inward movement.
Cover 6 is provided with a pair of T-slots 29 which are in line with the contacts in sockets l l and I2. When a plug with parallel blades is attached to the receptacle, the blades pass through the parallel heads of the T-slots and engage the contact ends 23 and 25, the blades passing between contact end 23 and the adjacent edge of contact end 25. The blades fit tightly therebetween thus giving good contact over relatively large surfaces. When a plug having tandem blades is attached to the receptacle, the blades pass through the arms of the T-slots, that is the portions of the T-slots at right angles to the heads, and engage the outer curved surfaces of the contact ends 25, the blades passing between such surfaces and the adjacent surfaces 26 of the base.
In cover 6 is an opening 30 for the face plate screw which passes through such opening and screws into a tapped opening in the cross bar.
In assembling the construction, the strips 2| and 22 which form the contact bars are nested and the screws 28 inserted to hold them together. The assembled contact bars are then inserted in the base, the cross bar put into position on the base and the cover then placed on the base and fastened by screws inserted through screw openings 1 and screwed into the underside of the cover. Thus the receptacle can be quickly and easily assembled.
The contact strips 2!- and 22 can be formed from strip material and given the desired shape by the use of simple machine operations and without waste of material.
After being shaped, the contact strips may be quickly and easily assembled relatively to each other and by reason of theirshape provide surfaces for engagement with either parallel bladed plugs or tandem bladed plugs. This arrangement whereby by the use of two contact strips, I provide in a simple manner contact bars for making contact with either parallel or tandem bladed plugs, I regard as being an important feature of my invention.
While I have shown my improved contact strip as being used in-a receptacle having T-slots, it will be clear that they may be used in a receptacle having other than T-slots, for example, the usual parallel slots, and? that in such a receptacle they ofier substantial advantages in that they provide contact strips which engage both sides of the blades of a plug having parallel blades.
What I claim as new and desire to secure by Letters Patent of the United States, is:
l. A duplex plug receptacle comprising a body of insulating material having a pair of sockets at each end and T-slots' in line with the sockets for the insertion of plug blades, and contact bars, each comprising two strips of material, extending longitudinally of the body in parallel relation to each other with their central portions in flatwise engagement and with their ends in said sockets, the ends of one strip being positioned at an angle to and presenting end edges to sides of the other strip, and said ends being so located as to make contact with the blades of plugs having either parallel or tandem blades.
2. A duplex plug receptacle comprising a body of insulating material having walls defining central side openings on opposite sides, a pair of sockets at each end, passages connecting the openings to the adjacent sockets, and T-slots in line with the sockets, and contact bars each comprising two strips of material having U- shaped central portions in parallel flatwise engagement located in the side openings and ends projecting through said passages into the sockets, the ends of one strip being positioned at an angle to and presenting end edges to sides of the other strip, and said ends being so located as to make contact with plugs having either parallel or tandem blades.
3. In a plug receptacle, a body of insulating material having sockets and T-slots in line with the sockets, and contact bars having portions outside said sockets and ends projecting into said sockets, each contact bar comprising two strips of material, the portions of said strips outside said sockets being in parallel flatwise engagement with each other and having terminal screws therein, and the portions in said sockets having the end of one strip positioned at an angle to the end of the other strip with an edge adjacent to a side thereof, such side and edge being in line with one portion of a T-slot, and a side of said one strip being in. line with another portion of such T-slot,
4'. In a plug receptacle, a body of insulating material having sockets and slots in line with the sockets, and contact bars having portions outside said sockets, and ends projecting into said sockets, each contact bar comprising two strips of material, the portions of said strips outside said sockets being in parallel flatwise engagement with each other and having terminal screws therein, and the portions in said sockets having the end of one strip positioned at an angle to the end of the other strip with an edge adjacent to a side thereof, the space between said edge and side being in line with a slot.
5. A duplex plug receptacle comprising a body of insulating material having a pair of sockets at each end and parallel slots in line with the sockets for the insertion of the blades of aplug having parallel blades, and contact bars each comprising two strips of material extending longitudinally of the body with their ends in said sockets, the central portions of the strips being in parallel flatwise contact with each other and the ends of one strip being positioned at an angle to and presenting end edges to sides of the other strip, the space between such edges and sides being in line with said slots.
6. A contact bar for a duplex plug receptacle comprising two strips in flatwise engagement with each other having nested U-shaped central portions and ends projecting outwardly therefrom, the ends of one strip being reversely bent to present end edges to side surfaces of the ends of the other strip, and a binding screw in said central portions.
7. A contact bar for a duplex plug receptacle comprising two strips which throughout their length are vertical to the same plane, said strips having their central portions in parallel flatwise engagement and each having an end of one strip reversely bent on itself to present its vertical end edge transversely to a side surface of an end of the other strip and adapted to receive a plug prong therebetween, and a binding screw in said central portions.
GEORGE B. BENANDER.