US2490429A - Terminal plug - Google Patents

Description

Dec. 6, 1949 E, E, @RANGER 2,490,429

' TERMINAL PLUG Original Filed Aug. 15, 1944 @a :Za

. /9 20' 20 /2 lf /4 6 /4 0^ 23 A? 4 l5 /f 7 INVEN TOR 'EL MER '.GRANGER A TMR/VET `Patented Dec. 6, 1949 UNITED STATI-:s y PA-Tem" OFFICE Original application August 15,. 1944, Serial No. 549,611. Divided and this application September 4, 1945, Serial No. 614,376 l n 1 Claim. (Cl. 173-361) This invention relates vto an electric outlet plug and constitutes a division from my cepending application for patent upon an electric outlet box led August 15, 1944, Serial No. 549,611, now Patent No. 2,423,016, issued June 27, 1947.

One object of the invention is to provide a plug having contact strips projecting from sid-eportions thereof and servingas means for retaining the plug in operative engagement with an outlet box as well as for engaging bus bars in the box and causing power to be delivered to an electrical appliance from which leads feed wires to which the plug is attached.

Another object of the invention is to provide a plug so formed that when itis thrust into an outlet box through an opening in the front wall thereof it must be turned and disposed transversely of the opening in order to make contact with the bus bars or strips in the box.

Another object of the invention is to provide a plug having its contact strips so located that they will be disposed radially of the shank of the plug in such positions that screws for holding wires to the strips may be very easily unscrewed for application of the wires to them and then easily tightened.

Another object of the invention is to provide a plug which is simple in construction and not liable to be easily broken if the plug should be dropped upon a floor.

The invention is illustrated in the accompanying drawings wherein:

Figure l is a View showing plugs of the improved construction in elevation and engaged in an outlet box shown in longitudinal section.

Figure 2 is a view showing the outlet box partlally in longitudinal section with a plug of the improved construction engaged therein.

Figure 3 is a view looking at the inner end of the plug.

Figure 4 is a sectional view taken longitudinally through the plug.

The outlet box shown in Figures l and 2 is of the construction shown in the copending application, referred to above, and has a casing I which ts into a wall box 2 where it is secured by an anchoring strip 3. A cover plate or block 4 formed of insulation is held in closing relation to the casing I by screws 5 and this plate or block has been shown formed with a pair of openings 6, each of which has its midportion 6 enlarged to form a substantially circular passage midway the length of the opening. While two openings B have been shown in the block or plate it will be understood that one opening or as many openings as desired may be provided.'k The usual vcover plate 'I is provided and formed with an opening through'which the openings 6 are exposed.k Bus strips 8 extend longitudinally -in the casing with tongues 9 projecting through side walls of the casing and certain of the tongues carry screws I0 for connecting power wires I I with the bus strips.

It will be understood that the plugs constituting the subject matter of this invention may be used in connection with any wall box including a casing having bus strips extending longitudinally therein adjacent its side walls and a closure block for the casing formed with openings extending longitudinally of the block and having enlarged intermediate portions.

The improved plugs are formed as shown in Figures 1, 3, and 4 and each plug I2 has a shank I3 formed with a head or finger hold I4 at its outer end. The shank is circular in cross section and of such diameter that it may be passed through the enlarged intermediate portion 6' of an opening 5 in the block 4 and iit snugly thereon. Contacts I5 are carried by the shank at opposite sides thereof. The contacts are formed from strips of conductive metal and have their rear ends secured to the shank by screws I6. The metal strips are bent to form U-shaped arms which project radially from the shank and have their front ends free and carrying screws I8 by which wires I9 of an electric cord 20 are secured to the contact strips I5. The electric cord passes through a bore or passage 2| formed longitudinally of the plug, and at the front end of the shank are formed notches 22 through which the wires I9 pass.

When the plug is applied to the outlet box, its shank is thrust inwardly through the opening 6 with the shank tting snugly in the enlarged portion of the opening and the contact strips I5 passing through end portions of the opening. The plug is then turned a quarter turn and, when one of the arms I'I engages the stop 23 extending downwardly from the inner face of block the arms Il will be disposed transversely of the casing and their resiliency will cause them to frictionally bear against the under face of the cover plate or Iblock 4 and lprevent the plug from accidently turning towards a position longitudinally of the casing in which the plug may move outwardly through the opening in the block. The fa-ct that the contact strips are formed of resilient metal also causes them to have `bindlng engagement with the bus strips and since they engage the bus strips in spaced relation to fulcrums 24 projecting from side walls of the casing and engaged by midportions of the bus strips, the bus strips will be flexed somewhat and additional binding created between the contact strips and the bus strips. Since the plugs must be thrust into the casing and then turned in order to make contact between the arms I1 and the bus strips, the plugs may not slip outwardly and drop from -the "-wall box iorybecome disengaged from .the bus strips to such 'an extent that arcing will occur and cause a fire to be started. When the plug is to be removed a reverse turn is imparted to it until turning motion is again stopped by contact of an ar-m I'l with the 'stop between the head and the rear ends of said wirereceiving notches and spaced from the said head and the notches, each contact being formed from a strip of resilient metal bent to form a at bridge constituting the outer en-d of the contact and front and rear arms extending from front and rear edges of the bridge towards the body, the rear arm lbeing formed with 4a, rearwardly Vprojecting foot rmly secured to the portion of the body between the rear arm and the head, and

the front arm being free from the body and 23 and outward pull exerted to withdraw the plug from the wall box.

Having thus described the invention, what is spaced from the body and carrying a wire-secur- ELMER E. GRANGER.

REFERENCES CITED The Vfollowing references are of record in the le :of this patent:

UNITED STATES PATENTS Number Name Date 696,597 Russell Apr. '1, 1902 `r187,338 Lutz Apr. 11, 1905 795,668 Waters et al. July 25, 1905 1,593,985 Nielsen July '27, 1926 `1,594,856 Slade Aug. 3, 1926 1,615,726 Row Jan. 25, 1927 2,180,569 Walls Nov. 21, 1939

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