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Publication numberUS2643787 A
Publication typeGrant
Publication dateJun 30, 1953
Filing dateNov 24, 1950
Priority dateNov 24, 1950
Publication numberUS 2643787 A, US 2643787A, US-A-2643787, US2643787 A, US2643787A
InventorsRockman Benjamin W
Original AssigneeRockman Benjamin W
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Lockable container for electrical connectors
US 2643787 A
Abstract  available in
Previous page
Next page
Claims  available in
Description  (OCR text may contain errors)

June 30, 1953 B. w. RocKMAN 2,643,787


. Ill lllllhl Cttorneg Patented `une 30, 1.9573

ILooKABLE coNmAnvEa Fon ELEC-Talon, vcommerces Beniatnn Rockman, Takoma Park, Md. v.application November 24, 195o., serial No. -197,413


This invention relates to a safety or lockdevice known as a plug lock, a receptacle of I'netal or other suitable material, 'for all types of electrical equipment having a cord and plug 'by means of which plug said equipment is oonnected to operating current outlets. The 'particular construction and nature is more `fully disclosed hereinafter.

The primary object of the Vinvention is to p'rovide a means by which the use of electrical equipment can effectively be denied those lacking consent for the use thereof.

As is well known, many novel devices have `been manufactured, patented, and sold for the purpose of securing electrical outlets 'against unauthorized use such as is disclosed in the patent to Frederick E. Reinhold in Patent No. 1,783,342, which discloses 'a plug adapted to be locked into the posi tion in the sockets of various receptacles, fuse boxes, cutouts and the like.

An object of my invention is to obviate the necessity of locking every electrical outlet to which electrical equipment may be connected for unauthorized use by the simple expedient of securing the equipment itself with a lock which prevents connection of the equipment to any electrical outlet.

A further object of the present invention is to provide a plug lock which, when properly constructed and insulated, 'can be used to prevent unauthorized use of live lines using plugs or jacks.

A more specific purpose of the present invention is to provide a safety device which, when used on plugs attached lto machinery, will deny to children, in particular, and to other un authorized individuals the use of power tools, electric irons, laundry equipment, kitchen equipment and other electrical devices, which when improperly used may cause seriousbodily harm or property damage.

Still another object of this invention is to provide the owner of expensive equipment, such as television sets, electric lawn mowers, hedge clippers, to name a few, the privilege of granting or denying the use of the equipment as long as the plug is secured by a plug lock.

Other objects and advantages of this invention will become apparent from a study of the following specification, taken with the accompanying drawing wherein:

Fig. 1 is an exploded view in perspective of a plug lock. I

Fig. 2 is an enlarged longitudinal sectional view. Fig. 3 is a cross section on line V'3-3 of Fig. 2.

Fig. e is a longitudinal section on line' 4-'4 Iof Fig-3.


2 Referring more particularlyto Fig. 1, I is a sleeve like container into which the sleeve 2 may be inserted and locked in place.

The outer sleeve I comprises closed side Walls andend wall i with an opening 5 on the end opposite the rendl wall The outer sleeve I has v built Vinto its v closed end walls a trunk type locking means Thefinner sleeve 2 comprises three closed side walls 7, an end wall 8 and an opposite open en d into which .is positioned vthe keeper Q of a trunk type lock in which 'are four keeper slots II) (for a purpose to be subsequently described).

The rear end wall f8 ofthe inner sleeve 2 contains a cutout I of sufficient size to accommodate an ordinary insulated wire I2 therethrough. The edge of the cutout YIl is covered with a bead i3 to protectv the insulation on the wire l2 from wear and damage in the insertion and removal of same. In ddi'tion, there isa flange It formed by extending the rear wall s beyond the side walls I and open top and which serves to make a 'tight Yj oir-1t when the inv-ner sleeve 2 is fitted into th outer 'sleeve l and tlfiedevice is in the closed or operative position, Fig. 2.

The 'plug I5 of an electrical device (not shown) is placed 'in the receptacle formed by the ir'lner sleeve `2 with its connecting wire I2 leading into the receptacle through the cutout II in the rear Wall '8 of the inner sleeve 2.

The open side I6 of thesleeve member 2 is provided 'with triangular shape braces I'l which are found on 'either side of the adjacent rear wall 8 t0 Strengthen the inner sleeve andis additionally provided witha cross brace member I8 adjacent the 'open side I oonn'ect'ing opposite side walls i to strengthen the end opposite the r'ar wall 8. After Vplacing the plug I5 into the inner sleeve 2 in the `manner indicated in Fig. l, 'the inner sleeve is 'insertedinto the outer sleeve I and snapped shut as illustrated in Fig. 2.

The plugl is now secured and may not be removed from the plug lock` except by an authorized person using 'a key I9 to release the lock 2e.

Upon insertion of the key I9 into the lock 20 and turning deckt/isc, thebons 2s are forced to the opposite ends of their respective guide `slots 3o inthe casing 22 of 'the locking means fs thereby withdrawing the bolts 2| from Athe keeper slots I I).

- The bol'tszl areinorrnally held in an extended position by springs 23 as indicated in Fig'. 3. Theses'pri-ng's' 23 rnay be 'omp'ressed by vuse of keeper'slots lIl) a'id 'thereby Opening the lock 1? by pressing the keeper 9 against the lock 20 when the two sleeves are engaged snapping the lock 20 shut without the use of a key.

The locking means 6 is provided on its keeper 9 with a bullet type ejector as indicated in Fig. l and Fig. 4. This comprises a cylindrical casing 24 in which is seated a bullet type ejector member 25 which is urged by a spring 26 to project beyond the cylindrical casing 24 and to seat on the internal shoulder 2I therein. The spring 26 is mounted on a rear plate 28 and is adapted to be compressed, as shown in Fig. 2, to allow the bullet member 25 to be received completely inside of the casing 24. Upon release of the lock 2Q the spring 26 expands and the bullet type ejector 25 forces against the back of the lock 2U on the casing- 22 and the inner sleeve 2 is forced or partially ejected from the outer sleeve I as shown in Fig. 4.

Referring to Fig. l, there is indicated at 29 a stop bead soldered at the open end of the outer sleeve I and so located as to complete the bead I3 of the cutout I i on the inner sleeve.

The bead 29 acts not only to complete the cutout Ii on the end of the inner sleeve 2 but also functions as a stop by extending below the inner surface of the outer sleeve i and is adapted to engage the cross member I8 on the inner sleeve 2 to prevent complete separation of the two sleeves unless additional force is applied.

- As pointed out previously, the keeper 9 is provided with four keeper slots I0. This is to enable the device to be operated with the sleeves in any relative position and still have the bolts 2I engage a pair of keeper slots I0. This feature is important where the device is inserted in poor light or visibility and a speedy operation is desired.

Fig. l may be modified by omitting the stop 29.

instead of stop portion 29, a slot may be made on opposite sides of the inner sleeve 2 into which will engage a shoulder rivet fastened on two sides of the outer sleeve I which would prevent at all times a complete separation of the two units.

Both units may be modied by making them circular rather than square. However, square assembly is preferable for the reason that the device will not roll away from the place when it is deposited when not connected with the wall plug. The device may be made hexagonal or in any other shape which will prevent rolling.

The plug lock may be made of any suitable material such as metal or plastic, plastic preferred as being lower in cost of production. The

lock 20 in outer sleeve i and the keeper 9 inv v inner sleeve 2 may be molded into the plastic by any suitable method.

Cutout II on the inner sleeve 2 is an opening -in which rests the cord running from the electrical unit to the plug end I5. This may be beaded by reinforcement of metal or by the thickness of plastic for the purpose of preventing the cord leading from the electrical unit or the plug end being worn or damaged.

Complete separation of the outer sleeve I and inner sleeve 2, as a result of the action of the spring 26 after the lock is released, may be prevented by linking a small chain at any suitable position on the outer sleeve I and inner sleeve 2. Said connecting chain may also be used as a means of suspending the unit in any suitable location.

The device may be provided with any suitable means of hanging it up when not in use; such as a loop or eye fastened to the outer sleeve I.


l. A lockable container for an electrical connector, comprising an outer sleeve having means for closing one of its ends, an inner sleeve and a suitable locking means; the sleeves being so adapted as to permit the inner sleeve to be locked in telescoping relationship within the outer sleeve and said inner sleeve being provided with a wall at one end, said wall being provided with a wire receiving cutout, a spring pressed plunger supporting means at the opposite end of said inner sleeve, a spring pressed plunger in said supporting means, said outer sleeve having a closed wall at one end thereof and said plunger being adapted to engage the wall of said outer sleeve when the sleeves are in telescoped position, and a keyhole slot on the opposite side of said last-named wall, said slot forming lpart of said lock means.

2. A device as dened in claim l in which the outer sleeve is provided with an open end and a closed end, said open end receiving said inner sleeve therethrough, said outer sleeve adjacent the open end being provided with a bead so located as to prevent the complete separation of the outer and inner sleeves without the application of additional force by engaging said inner sleeve, said inner sleeve having a bead on one end thereof adjacent said wire receiving cutout, whereby when said inner sleeve is completely inside of said outer sleeve said outer sleeve bead will form with said inner sleeve bead a protective covering around the space formed by said wire receiving cutout.

3. A device as defined in claim l, said spring pressed plunger comprising a bullet type ejector fastened in said inner sleeve at the end opposite the wall end in such a manner as to force the partial separation of the two sleeves when said sleeves are unlocked.

4. A safety device to prevent unauthorized use of electrical equipment comprising a two section separable housing for an electric plug with locking means to lock the housing in closed position, a rst section or said housing formed with three side walls and an end wall, one side and one end of said section being open, an electric wire re ceiving notch in said endwall with the open end of said notch communicating with said open side of said section, said section being adapted to receive through its open side an electric plug with its attached wire adapted to pass through said notch, a second section of said housing formed with four sides and an end wall, said ilrst section being adapted to slide inside of said second section so as to form a closed housing, said locking means being mounted in the end wall of the second section and in the open end of the first section so as to engage and lock when said housing is closed and spring operated ejecting means for partially ejecting said iirst section from said second section when said locking means is released.

5. A device of the character described, comprising an outer sleeve, anl inner sleeve and a locking means, said outer sleeve being provided with one open end and an end wall closing the opposite end, said inner sleeve being provided with one open end, one open side and a wall closing the opposite end, said locking means comprising a lock mounted in said end wall of the outer sleeve and a keeper mounted in the open end of the inner sleeve, said lock being adapted to engage and lock with said keeper when said inner sleeve is inserted inside of said outer sleeve, said inner sleeve being provided with a cutout portion in the end Wall communicating with said open side and being adapted to allow an electric wire to pass therethrough and said inner sleeve being of a size to receive an electric plug inside thereof, said cutout portion being of a size smaller than an electric plug.


References Cited in the file of this patent UNITED STATES PATENTS Number Name Date 390,559 Brooks Oct. 2, 1888 575,621 Smith et al. Jan. 19, 1897 Number Number Name Date Smith Mar. 11, 1919 Lay Apr. 26, 1927 Robbins Apr. 4, 1944 Page May 17,' 1949 FOREIGN PATENTS Country Date Germany Apr. 14, 1924 Germany Oct. 10, 1930 France May 17,1933

Patent Citations
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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2733416 *Apr 5, 1955Jan 31, 1956 Locking device for use with electrical
US2844805 *Feb 17, 1956Jul 22, 1958Darrell George HPlug locking and protecting device
US2955272 *Mar 10, 1959Oct 4, 1960Juan GallardoTelevision and electric appliance lock
US2987909 *Nov 25, 1958Jun 13, 1961Shlank William ILocking cover assembly for electrical wall outlet boxes
US3524029 *Jul 22, 1968Aug 11, 1970Laff Robert MKeylock for electrical plugs
US3792414 *Mar 15, 1972Feb 12, 1974Lyall ElectricPower cord hatch
US3902340 *Jan 2, 1974Sep 2, 1975Roger J LeydenDiamond needle lock and the like
US4488764 *Jul 12, 1982Dec 18, 1984Pfenning Bruno APortable security container for an electrical cord and attached plug
US4563048 *Jan 11, 1985Jan 7, 1986Im Kwan SLocking device for an electrical plug
US4593541 *May 7, 1984Jun 10, 1986Nathaniel HollisLocking electrical outlet box
US4666224 *Jun 9, 1986May 19, 1987Fields Thomas JDevice for securing electrical connectors
US4669281 *Oct 9, 1984Jun 2, 1987Hewlett-Packard CompanyCable/computer peripheral lock
US4782971 *Aug 11, 1987Nov 8, 1988Hill Mary VDevice for preventing the unauthorized use of an electrical apparatus
US5061199 *Mar 14, 1991Oct 29, 1991The United States Of America As Represented By The Secretary Of The NavyWall outlet lock apparatus
US5186636 *Mar 27, 1992Feb 16, 1993Boyer David JElectric plug lock
US5277599 *Oct 23, 1992Jan 11, 1994Nilson Donald LLockable container for securing an electrical connector
US5393237 *Sep 22, 1993Feb 28, 1995William J. RoyElectric plug locking device
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US5904261 *Aug 6, 1996May 18, 1999Draw-Tite, Inc.Enclosures and mounting box for a trailer hitch electrical connector
US6056563 *Mar 3, 1997May 2, 2000Betzler; John R.Electrical cord lock
US6076691 *Apr 20, 1999Jun 20, 2000Mascotech Inc.Adjustable enclosure and mounting box for a trailer hitch electrical connector
US6185964 *Dec 1, 1999Feb 13, 2001Raphael AddiegoSecurity device to prevent use of a mouse
US6367293 *Dec 8, 2000Apr 9, 2002Timothy J. ElliottLock for the plug of a power cord
US6477870 *Jan 4, 2002Nov 12, 2002Jay S. DermanCable end tubular lock
WO2006060907A1 *Dec 6, 2005Jun 15, 2006Salfinger RoderickElectrical equipment lockout device
U.S. Classification220/3.2, 220/3.8, 109/59.00R, 70/57, 439/133
International ClassificationH01R13/44
Cooperative ClassificationH01R13/44
European ClassificationH01R13/44