US 2775744 A
Description (OCR text may contain errors)
DCC 25, 1956 F. G. HEUNEMAN ELECTRICL PLUG CONNECTOR F11/Qd Jan. 11. 1954 United States Patent O ELECTRICAL PLUG CONNECTOR Fred G.-Heuneman, Livingston, N. J. Application January 11, 1954, Serial No. 403,216 2 Claims. (cl. 339-74) This invention relates to an improved electrical plug connector for detachable insertion into a wall outlet or like receptacle, whereby to connect the circuit wires of an appliance cord or cable to an electric service circuit in which the outlet or receptacle is included.
The invention has for an object to provide a plug connector having movable contact blades and manipulatable means to control the contact blade movements whereby, upon operative insertion of the plug in a wall outlet or like receptacle, said contact blades will substantially interlock with the latter against accidental separation therefrom.
The invention has for a further object to provide a plug connector having a pair of spaced contact blades pivotally mounted within the plug body or casing to project outwardly from the latter; said contact blades being spring urged to swing-about their supporting pivots so as .to divergently spread their outwardly projecting portions, when the same are entered in a wall outlet or like receptacle, whereby to both force said contact blades into good and iirm electrical engagement with internal contact elements of the outlet or receptacle and to secure the plug to the outlet or receptacle against accidental pulling away and disconnection therefrom; manipulatable means being provided for swinging lthe contact blades against the tension of their spreading spring means to normal positions parallel one to the other, so as to facilitate entrance thereof into or withdrawal thereof from the outlet or receptacle, as the case may be.
The above and other objects will be understood from a reading of the following description of an illustrative embodiment of the invention as shown in the accompanying drawings, in which:
Fig. l is a face view of the electrical plug according to this invention, showing the movable contact blades as normally positioned in parallel relation for insertion into or withdrawal from an outlet or other receptacle; Fig. 2 is a view similar to that of Fig. 1 but with a cover plate of the plug body or casing removed to disclose the internal parts of the structure; Fig. 3 is a view similar to that of Fig. 2, but showing the contact blade control means positioned to -allow spring urged spread of contact blades; Fig. 4 is a transverse Ihorizontal section, taken on line 4 4 in Fig. 3; and Fig. 5 is another transverse horizontal section, taken on line 5-5 in Fig. 3.
Similar characters of reference are employed in the above described views, to indicate corresponding parts.
Referring to the drawings, the plug connector comprises a two part body formed by a main casing and 2,775,744 Patented Dec. 25, 1956 ICC ance to be served by the plug connector, can be entered. Leading outwardly from the chamber 13 through the bottom end of the plug body is an opening or mouth 17.
Pivotally supported in connection with the plug body are a pair of laterally spaced apart metallic contact blades 18 and 19, each formed to provide an upper internal arm 20 lying within the plug body chamber 13, and a lower external arm 21 to project through the bottom opening or mouth 17 exteriorly of the plug body. Each contact blade 18 and 19 is provided intermediate its arms 20 and 21 with a hinging knuckle 22 projecting from its outer face, through which extends a pivoting pin 23 that is suitably atiixed to the plug body, preferably by imbedding the ends thereof respectively in the casing face Wall and in the cover plate for bridging extension between these parts within the chamber 13 (see Fig. 4), and in location above but adjacent 4to said bottom opening or mouth 17 of the plug body. As thus pivotally supported, said contact blades can rock about ,their fulcrums in plane parallel to the face planes of the plug body.
Engaged between respective side edge walls of the casing 10 and the upper arms 20 of the respective contact blades 18 and 19 are compression springs 24. The side edge walls` of the casing 1i) are provided with means by which said springs 2.4 are footed or purchased to exercise yieldably in swinging thrust against the upper arms 2o of the contact blades, with resultant divergent relative spreading of the exteriorly projecting external arms 21 of said contact blades; said footing means preferably comprising sockets 25 in which outer ends of said respective springs are seated..
Formed in connection with the free ends of the upper arms 20 of the respective contact blades 13 and 19 are internally screw-threaded perforate ears 26 tted with binding screws 27 by which respective conductors 28 and 29 of the cord or cable 16 can be electrically connected with said respective contact blades 18 and 19.
Movably mounted within the internal chamber 13 of the plug casing 10, intermediate the upper arms 20 of the contact blades 18 and 19, so as to be vertically slidable in said casing toward and from an aligned position relative to and between the pivotal fulcrums of said contact blades, is a manipulatable blade control member 30,
a cover or face plate 11 which is removably secured to which isl preferably of -circular cross-section. Projecting from at least one end and preferably from each end of said control member 30, is a linger piece or linger pieces 31 of reduced diameter to project through a vertical guide slot or slots 32 with which one or each side face wall of the plug casing is provided.
When the control member 30 is shifted to its normal upward or inward limit of its movement relative to the plug casing 10, it is thereby moved between the upper arms 20 of the contact blades 18 and 19, whereby to rock sai-d blades about their pivoting fulcrums against the tension of the compression springs 24, thus swinging the contact blades to positions in which they are parallel one to the other, whereby the externally projecting arms 21 thereof are disposed in straight parallel positions for Ialignment with, and easy entrance into, the spaced admission openings of an outlet or other receptacle to which the plug is desired to be operatively connected (see Fig. 2).
After the plug is inserted in an outlet or receptacle to which it is to be connected, the control member 30 is manually shifted to its downward or outward limit of movement, as determined by the guide slots 32 in which the nger pieces 31 ride, whereby to align the same with and between the pivotal fulcrums of the contact blades 18 and 19 (see Fig. 3). When the control member is so positi'oned, it can no longer resist rocking movements of the contact blades about their pivotal fulcrums under the thrust of the compression springs 24, and consequently the inserted arms 21 of'the contact blades will be divergently spread, so as to both force the same into good and firm electrical engagement with the internal contact elements of the outlet or receptacle, While at the same time thereby serving to obstruct outward withdrawal of said arms 21 fromthe outlet or.receptacle,tandthus substantially securing the plug against accidental out pulled. disconnection fromsaid outlet or receptacle.
To. withdraw the plug from an outlet or receptacle to which it is operatively connected, it is necessary to merely engage the iinger pieces 31 of the control member 30, so that, by pulling the plug outwardly thereby, the control member 30. will first be moved relative to the contact blades 13. and 19, whereby to return said blades to parallelism, whereafter continuedy outward pulling of the plug will easily withdraw the parallelly straightened external arms 21- of the Contact blades out of and away from the outlet or receptacle.
From the above, it should now be understood that the instant invention provides a very simple and yet easily manipulatable plug connector for assuring both good contact thereof with an outlet or receptacle in which it is inserted, as well as one substantially guarded against accidental withdrawal and separation from the outlet or receptacle.
`Having now described my invention, I claim:
l. A plug connector for an electrical cord comprising a chambered casing, a pair of laterally spaced contact blades pivotally mounted intermediate their ends within said casing atpoi'nts adjacent to the outer free end of the latter, said contact blades each having an internal arm and an external arm outwardly projecting from said casing, compression springs mounted within said casing to eXertyieldably in swinging thrust against said internal arms of the contact blades whereby to divergently spread the external arms of said contact blades, means to couple respective electrical cord wires to the ends of the respective internal arms of said contact blades, a control member of substantialiy circular cross section slidably disposed within the casing for longitudinal movements intermediate and in engagement with the internal arms of the contact blades to and inwardly from an outwardly moved, horizontally aligned position between the pivotal points of said contact blades, whereby, in the latter position, diametrically opposite curved peripheral surfaces of said control member are opposed to the pivotal points of respective contact blades in noneobstructing relation to spring induced rocking movement of said contact blades about their pivotal points, but, when inwardly moved away from said pivotal points, to rock said blades against spring tension to parallelism, said control member having linger engageable means, externally projecting from the casing, by which the same can be manipulated.
2. A plug connector according to claim 1, wherein the linger engageable means of the control member comprises oppositely and horizontally projecting finger pieces, and the casingl having slots in opposite face walls thereof through which said finger pieces respectively project, said slots guiding and limiting the inward and outward movements of the control member.
References Cited in the ile of this patent UNITED STATES PATENTS 1,957,773 Good May 8, 1934 2,043,851 Grant June 9, 1936 2,075,632 Zuckerman Mar. 30, 1937 2,195,546 Townsend Apr. 2, 1940 2,254,754v Reece Sept. 2, 1941 2,436,586 Mangold Feb. 24, 1948 FOREIGN PATENTS 463,842 Great Britain Apr. 7, 1937