US 3775726 A
A safety receptacle constructed for use in conventional electrical junction boxes to accommodate standard electrical plugs. The construction of the receptacle prevents completion of an electrical circuit until a standard plug with holes in the ends of its blades is pushed into the receptacle. The plug engages a spring loaded block means therein, and the plug and a sliding portion of the receptacle face are translated laterally. The lateral translation of the plug and related portions of the receptacle causes fixed pins within the receptacle housing to extend into the holes in the plug blades and to lock the plug in place. This lateral translation also slides electrically conductive wiper means, which are in contact with the plug blades, from a non-conductive position to a conductive position on an electrical input bar. Translation of the plug and related portions of the receptacle back to their original position is required to unlock the plug. Translation also disconnects the wiper means from the electrical input bar and deactivates the receptacle.
Claims available in
Description (OCR text may contain errors)
United States Patent [191 Gress Nov. 27, 1973 SAFETY RECEPTACLE  Inventor: Richard D. Gress, Box 1056,
Whitefish, Mont. 59937  Filed: Sept. 13, 1971  Appl. No.: 179,875
 U.S. Cl. 339/14 R, 339/40, 339/75 P, 200/51 R  Int. Cl H011 3/06  Field of Search 339/36, 37, 38, 39, 339/14, 74, 82, 40, 75, 42, 91; 200/51 R, 51.07, 51.09
[5 6] References Cited UNITED STATES PATENTS 2,215,316 9/1940 Benander 339/91 R 3,467,941 9/1969 Martin 339/31 2,664,734 l/l954 McEneaney 339/37 3,214,726 10/1965 Cardenas et a1... 339/189 2,986,612 5/1961 Healy 200/51 Primary ExaminerMarvin A. Champion Assistant ExaminerRobert A. Hafer Attorney-B. Deon Criddle [5 7 ABSTRACT A safety receptacle constructed for use in conventional electrical junction boxes to accommodate standard electrical plugs. The construction of the receptacle prevents completion of an electrical.cjrcuituntil a standard plug with holes inthe ends of its blades is pushed into the receptacle. The plug engages 'a spring loaded block means therein, and the 'plug and a sliding portion of the receptacle face 'are translated laterally. The lateral translation of the plug and related portions of the receptacle causes fixed pins within the receptacle housing to extend into the holes in the plug blades and to lock the plug in place. This lateral translation also slides electrically conductive wiper means, which are in contact with the plug blades, from a nonconductive position to a conductive position on an electrical input bar. Translation of the plug and related portions of the receptacle back to their original position is required to unlock the plug. Translation also disconnects the wiper means from the electrical input bar and deactivates the receptacle.
7 Claims, 3 Drawing Figures PATENTED NOV 2 7 I975 INVENTOR:
RICHARD D. GRESS ATTORNEY.
SAFETY RECEPTACLE BRIEF DESCRIPTION OF THE INVENTION sticking hair pins or other metal objects into th'e'recep-- outlet box, and has a specially constructed bus bar therein to which electrical input wires coming into the outlet box are connected. The receptacle facing section contains at least one sliding socket assembly for receiving plug blade sockets and related components, and is joined by a screw means to the receptacle housing section.
The bus bar provides a wiping surface within the housing section on which electrically conductive .wipers that are joined to the sliding socket assembly proximate. to the sliding plug sockets move. The -bus'bar itself is constructed of an electrically non-conductive tacle sockets. Also, an improper or loose insertion of an electrical plug in a standard receptacle can cause a dangerous arcing of electrical current from the plug blades to the receptacle resulting in a burned recptacle face plate or a fire and possibly injury to the user. Standard plugs are easily pulled from conventional electrical recptacles and this may unintentionally break an electrical circuit supplying current to an electrical device. Also, having to repeatedly re-insert such a plug can be both time consuming and annoying. The conventional electrical outlets are therefore not entirely satisfactory.
Attempts have been made in the past to provide wall receptacles which will overcome some of these deficiencies. Wall receptacles incorporating switch means which activate the receptacles and allow entrance of specially constructed plugs, part of the receptacles and plugs being rotated to lock the specialplugs therein,
are taught by U.S. Pat. Nos. 1,700,437 and 3,066,276.
U.S. Pat. Nos. 3,543,218 and 2,733,416, disclose a receptacle and plug maintaining devices, each having locking means to lock an electrical plug therein. Though these prior art patents disclose plugs having locking features of various kinds, to my knowledge, there has not heretofore been available an electrical receptacle that can be used with conventional electrical outlet boxes and plugs and that combines plug locking and electrical current conduction from a receptacle which is inert until the plug is locked therein.
SUMMARY OF THE INVENTION Electrical power is transmitted from its source to its point of use through a distribution system wherein the equipment used and operations conducted are designed and operated with human safety as a primary consideration. Yet, when that same electrical energy is delivered for use to a residence human safety is apparently forgotton since the current frequently is conducted to sockets of a receptacle positioned near the floor, and easily accessible children who may stick wires or other such items therein.
The purpose of the present invention is to provide an electrical wall receptacle designed with safety as a prime consideration, which is compatible with standard electrical plugs and that is easily installed within existing electrical outlet boxes. Principal objects of the present invention are, therefore, to provide an electrical receptacle which fits into a standard electrical outlet box and that is arranged to be incapable of transferring electrical power until a standard plug is inserted and has been manipulated to be locked therein.
To accomplish these objectives. I utilize as principal features of the invention an electrical receptacle composed of housing and facing sections. The housing section is mounted by screw means in a standard electrical material, but has strips of electrically conductive material thereon leading frorri 'the bus bar points of contact with the electrical input wires to locations'at the top and undersurface of the bus bar. When an electrical plug is properly positioned and locked within the socket the blades of the plug will contact the electrically conductive portions of the bus bar.
Electrically insulated rod means with sharpened ends aligned to be inserted through the holes in the ends of the blades of an electrical plug are used to prevent plug withdrawal.
The blades of an electrical plug inserted into the Slid ing plug sockets force a spring loaded block away from the receptacle facing, thereby opening the locking hole in a plug blade alignment means which projects outwardly from its junction with the back of the sliding socket assembly. The spring means biases the blocks over the aforementioned locking hole when the plug blades are withdrawn from the socket. The block prevents the insertion of the rod means into holes in the plug blade alignment means if an attempt is made to laterally move the sliding sockets without prior insertion of an electrical plug that has blades with holes in their ends.
Stationary ground bars are positioned at the top and bottom of the receptacle housing to electrically contact the ground leg of a grounded plug. The gound leg of the gounded plug slides on the stationary bar to maintain continuous contact when the sliding plug sockets in the receptacle facing in which the plug is positioned are translated laterally.
Additional objects and features of the invention will become apparent from the following detailed description and drawings, disclosing what are presently contemplated as being the best modes of the invention.
THE DRAWINGS the outlet box and with aloeked position of an inserted electrical plug shown in phantom; and
FIG; 3, a vertical section taken along line 3-3 of FIG. 1, but showing the safety receptacle assembled in the outlet box.
DETAILED DESCRIPTION Referring now to the drawings:
In the illustrated preferred embodiment, the safety receptacle 10 consists of a housing section, shown generally at 11, and facing section, shown generally at 12. The housing section 11 is composed of top and bottom plates 13a and 13b, respectively, with a web member 14 extending normally between rear edges of the two plates. Ears 15a and 15b project from front edges of plates 13a and 13b and have holes 160 and 16b therethrough to accommodate screws 17.
The ears 15a and 15b align with ears 18a and 18b, which project from the front edges of top and bottom walls a conventional electrical outlet box 19. Ears 18a and 18b have holes 200 and 20b therethrough, which holes will align with holes 16a and 1622, when the housing section 11 is inserted into the electrical outlet box 19. The housing section 11 is securec in the outlet box by threading screws 17 through the aligned holes 160 and 20a, and 16b and 20b.
Electrical circuit wires 21a and 21b are inserted into the outlet box 19 before housing section 11 is placed therein and their ends, from which insulation has been stripped, are turned around threaded wire mounting posts 23a and 23b that project from electrically conductive strips 24a and 24b of an electrical transfer bus bar 22, and the screws are tightened into the bus bar. The bus bar 22 is mounted to project normally from the inner surface of web member 14 and essentially parallel to the top and bottom plates. A hole 25 is formed in a front end of the bus bar. Hole 25 is threaded to receive a screw 26 that is inserted through a countersunk hole 26a in the facing section 12 to connect the facing section 12 to the housing section 11, as shown in FIG. 3.
As illustrated, the safety receptacle includes similarly constructed upper and lower socket units. Conse quently it should be understood that the description hereinafter given, while directed to one such socket unit will apply to the other, as well. Obviously, a receptacle having more than the two socket units shown could also be constructed.
As has been previously noted, current is conducted into the receptacle 10 through wires 21a and 21b to posts 23a and 23b. The posts 23a and 23b are respectively electrically connected to conductive strips 24a and 24b on the electrical transfer bus bar 22. The body of bus bar 22 is constructed of a non-conductive material, so only the conductive strips 240 and 24b of the bus bar can conduct electricity. As shown best in FIG. 1, four parallel grooves 27a, 27b, 27c and 27d are formed in each of the top and the bottom of bus bar 22. Conductive strip 24a leads from screw 23a to and partially along each groove 27b, and conductive strip 24b leads from screw 23b to and partially along each groove 27d.
As best viewed in solid line showing of FIG. 2, the blades 29 of an electrical plug 30, inserted into plug blade sockets 28, force blocks 31 away from the facing section 12. Blocks 3] are each slidably mounted on a shaft 32, which is connected to and extends from a sliding socket assembly 33. A spring 34 surrounds that shaft 32 and is positioned between a head 35 on the free end of the shaft and the block 31 such that the" spring biases the block towards the sliding socket assembly 33.
As best seen in FIGS. 1 and 3 electrically conductive wipers 36 extend from shafts 32 to contact bus bar 22. The wipers extend into non-conductive grooves 27a and 270 prior to and immediately after insertion of plug blades 29 into the blade sockets 28 so no current is conducted prior to further manipulation of the sliding socket assembly.
37b of each rod 37 projects normally from the inner surface of web member 14 and the other leg 37c having the pointed end thereon extends at right angles thereto. The legs 37c are positioned to block lateral translation of blocks 31 when the blocks are fully biased towards the sliding socket assembly 33. When blocks 31 are moved away from the sliding socket assembly by insertion of objects through the sockets 28, holes 38 through the mounting shafts 32 are uncovered. When blocks 31 v .are moved away from the sliding socket assembly, by
insertion of objects through the sockets 28, holes 38 through the mounting shafts 32 are uncovered. Holes 38 are aligned with the legs 370 of rods 37 so that as the holes are uncovered, lateral translation of the sliding socket assembly 32 will cause the legs 37c to extend into holes 38 thereby allowing sufficient lateral translation for wipers 36 to move laterally into contact with the conductive strips in grooves 27b and 27d. However, the sliding socket assembly, including mounting shafts 32 cannot be translated laterally a distance sufficient to place the wipers 36 in electrical contact with the conductive strips if the objects insertedint'o the sockets in any way block hole 38, or if the objects do not move both blocks 31.
A conventional electrical plug as shown at 30 has a= hole 39 in the end of each of its plug blades, and when' the plug is fully inserted into blade sockets 28 the holes 39 are aligned with the holes 38 in the mounting shafts. The holes 39 are large enough to allow legs 370 of rod 37 to be inserted therethrough the lateral translation of sliding socket assembly 33 causes rod 36 to pass through the aligned holes. Rod 37 thereby securely locks the plug blades 29 against withdrawal from the receptacle as power is transferred to the plug through wipers 35. Reverse lateral translation to remove the sliding socket assembly from rods 37 moves wipers 36 from conductive strips 24a and 24b, thereby deenergizing the receptacle. It can be seen that a positive plug locking and safe power transfer is obtained with the safety receptacle of the invention.
Resilient plug blade guides 40 are provided within the receptacle, and project from the rear of the sliding socket assembly face to engage the wiper mountingshafts 32. The plug blades, when inserted into sockets 28 fit between and are guided by the alignment shafts 32 and the resilient guides 40.
and bottom of openings 46 in a face panel 47 of the facing section 12.
The preferred embodiment described herein discloses an electrical energy transfer device utilizing a lateral movement of'part of its structure to effect a power transfer therethrough. It should be apparent that the components herein described could be arranged and maintained differently to form a safety receptacle requiring vertical, rotational, or even slanted movements of its structure to effect a power transfer. Such rearrangement would not depart from the scope of the invention herein disclosed.
Although a preferred form of my invention has been herein described, it is to be understood that the present disclosure is made by way of example and that variations are possible without departing from the scope of the hereinafter claimed subject matter, which subjectmatter I regard as my invention.
1. A safety receptacle comprising a movable socket assembly including a face plate having sockets therein adapted to receive the blades of a conventional electrical plug;
means for guiding said socket assembly from a plug receiving position to a plug locking position;
rod means positioned to extend through at least one hole in a blade when said sockets have blades ininto the locking position until at least one hole in a blade is aligned with a hole in the socket asseri'i;'
bly, whereby said rod means will extend through the aligned holes. 3. A safety receptacle as in claim 1, wherein the means blocking movement comprises at least one shaft extending from the face plate adjacent to a socket;
a block slidably mounted on the shaft and in alignment with a socket;
means normally biasing the block to a position in alignment with the rod means, whereby said block engages said rod means to prevent movement of the movable socket assembly to the locking position, said block means being sidable to a position ther means to prevent movement comprises a'hole in the shaft.
6. A safety receptacle comprising a movable socket assembly including a face plate having sockets therein adapted to receive the blades of a conventional electrical plug; means forguiding said socketassem'b ly from a plug receiving .position to a plug lockingposition; rod means positioned to extend through at least one hole in a blade when said sockets have blades inserted therethrough and said socket assembly has been moved to its locking position; and means for completing an electrical circuit through the blades only when said socket assembly is in its locked position, said means comprising electrically conductive wiper means carried by said socket assembly and in continuous engagement with a blade of an electrical plug inserted into the sockets, and electrically conductive means positioned to be contacted by the wiper means only when said socket assembly is in its locked position. 7. A safety receptacle comprising a movable socket assembly including a face plate having sockets therein'adapted' to receive the blades of a conventional electrical plug and a socket through which a ground post of the electrical plug is adapted to be inserted;
' means for guiding said socket assembly from a plug