US2752413A - Electrical interlock - Google Patents

Description

ELECTRICAL INTERLOCK Filed 0d. 2, 1950 I/III/IIIII/I 5 2,752,413 ELECTRICAL INTERLOCK Arthur H. Junkins, Geneva, 11]., assignor to Admiral Corporation, Chicago, 111., a corporation of Delaware Application October 2, 1950, Serial No. 187,866

3 Claims. (Cl. 174-50) This invention relates to interlock switch devices for use in conjunction with high voltage power supply for television receivers whereby contact by an unauthorized person is prevented as long as the safety device is in a predetermined or normal position.

More specifically, the interlock device is particularly adaptable of use in conjunction with one of the sides of a television receiving set housed in a cabinet which side is removable. The outer wall member bears a pair of terminals, at the end of a power supply cable, which are adapted to cooperate, electrically, with another pair of terminals, in fixed relationship to an inner housing or cabinet, and in electrical connection with the high voltage producing means. The safety device is one of at least two elements of an inner cowling or housing providing, while in a normal position with respect to the other of the elements, an enclosure for the high voltage producing means within the cabinet. Furthermore, the safety device is movably anchored to another and fixed element of the cowling for movement away from its normal position so that access can be had to the high voltage producing means. Additionally, the normal position of the safety member is in such close proximity to the outer cowl member that it is necessary to completely remove said outer cowl member from the cabinet, thereby disconnecting the respective pairs of terminals from each other, before the safety member can possibly be moved substantially away from its normal position to afford access to the high voltage producing means.

In television receiving sets of earlier construction a practice, among others, has been to run a power conducting supply line directly to the chassis, to which the line was rigidly anchored and from whence leads continued to the high voltage producing means. In this construction it was essential that the supply of electric power be broken off at a point externally of and remote from the apparatus before access could be had to the high voltage source, with safety. In other television receiving sets a separable connection was provided by pairs of terminals adapted to be in complementary relationship to each other to provide for conveyance therethrough of an electric current from a suitable source to the high voltage producing apparatus. This second construction involved mounting one of the pairs of terminals on a cowling associated with the high voltage apparatus while the other of the pairs of terminals were on a cowling or removable foraminous wall, usually at the back of the cabinet. Since the foraminous wall was slightly resilient, it was possible for a portion of the wall to be loosened at one of its edges and bent away from the cabinet sufficiently for insertion of ones arm into engagement with high voltage conducting surfaces without first drawing one pair of terminals out of electrically conductive engagement with the other pair of terminals.

The present invention overcomes the foregoing disadvantages by use of a safety or interlocking member which plays the double role of affording cowling means, adapted to cooperate with other cowling means to envelop high nited States Patent 2 voltage producing apparatus, a supply current to which must be discontinued before access can be gained to the apparatus. Furthermore, the safety member enables the apparatus, in its entirety, to comply with requirements of the United States Board of Fire Underwriters.

Another advantage is the matter of convenience in mass production and/or servicing of television apparatus in which this device is included since one of the pair of terminals is supported within, and independently of, the inner cowling which is adapted to be added to assembly after soldered connections have been made. By such a construct-ion the inner cowling is also adapted to be removed from the high voltage producing means when and if disassembly is advisable, without the necessity of cutting or unsoldering leads from the high voltage producing means.

Other advantages of the invention will be set forth in part hereinafter and in part will be obvious herefrom, or may be learned by practise with the invention, the same being realized and attained by means of the instrumentalities and combinations pointed out in the appended claims.

The accompanying drawings illustrate one embodiment of the invention and together with the description serve to explain the principles of the invention.

In the drawings:

Fig. 1 is a fragmentary elevational view of a cabinet for a television receiving set, the same being broken away to reveal the inner cowling for the high voltage producing apparatus;

Fig. 2 is a view similar to Fig. l, the cowling being shown in open position;

Fig. 3 is a fragmentary exploded view, partly in section and partly in elevation;

Fig. 4 is a fragmentary elevational view of the end of the cowling in open position; and

Fig. 5 is a section taken on line 55 of Fig. 4.

In Figs. 1 and 2 the reference character 6 is used to denote a cabinet, in which is housed apparatus, not shown, such as used for television reception which must be operated by a high voltage current. One of the sides of the cabinet, usually the back, is at least partly closed by a removable wall or outer cowling 7. This wall is of any suitable material and is usually foraminous in structure to afford a flow of air :therethrough so that heat generated within the cabinet may be readily dissipated. Although the television apparatus per se is not shown, it is supported by a frame or chassis 8 within cabinet 6. Chassis 8 carries high voltage producing apparatus, part of which is indicated by the character 9, and an inner housing member 11 to partly enclose the high voltage producing apparatus.

Details of the structural features of the safety member include a terminal fixture 12 (Fig. 1) comprising male and female composite coupling elements 13 and 14 (Fig. 3). The element or plug 13 is carried by the wall 7 while the element 14 is supported, from the chassis 8, by a bracket 16. The element 14 includes terminal plugs or prongs 17 which are coupled by leads 18 to the high voltage producing apparatus 9 and are adapted to be received in sockets 19 to which a supply cable 21 is in electrical communication. The element 13 may take the form of any suitable fixture, the sockets 19 of which are substantially encased in rubber 22 which may be an integral part of the insulation of cable 21. Additionally, the rubber extends laterally in the form of flanges or ears 23 through which rivets 24 extend, to rigidly secure the element 13 to the outer cowling 7. When the prongs are in cooperation with the sockets 19 the outer cowling 7 is adapted to be attached to the cabinet 6 by a series of screws 26, one of which is shown in Fig. 3 for extension through one of a series of holes 27 at the edges of the cowling.

The inner cowling 11 may be bolted to the chassis and includes vertical side walls 28, in parallel relationship to each other. Walls 28 extend from a vertical front wall, not shown, to flanged rear edges 29 in extension toward each other. The top and rear end of the cowling 11, although open, may be closed by a movable cover member 31 which is L shaped in vertical section (Fig. 2). Member 31 performs the function of a safety or interlocking member and includes, at the edges thereof, flanges 32 which add rigidity to said member and are adapted to embrace the sides 28. Continuations of the flanges 32 provide a pair of arms 33 at the lower end of the cover which are ivoted at 34 to the walls 28 so that cover 31 is adapted to be swung from the enclosing or normal position in which it is indicated in Fig. 1, to the extreme open position indicated in Fig. 2 wherein access may be had to the apparatus 9 through the top and end of cowling' 11.

As was previously indicated, the female socket 14 is carried by the bracket 16. Said bracket includes a base portion 36 which is preferably bolted to the chassis S. It is offset transversely of itself at 38 in order that it may extend behind the cover member 31 when said cover member is closed. It has a socket carrier portion 37 at its upper end which is bifurcated by a notch 39. A terminal cup or socket 43. having ears 42 overlaps the carrier portion to which said cup is riveted at 43. The bottom of the cup 41 is formed with an opening 44, the edges of which provide flanges that are sandwiched between plates of insulating material 46 and 47 through which the terminals 17 extend. The edges of plate 47 closely register with the internal wall surface of cup 41. Consequently, the pins 17 are retained against lateral displacement while clamping pressure applied to plates 46 and 47 by collars 48 and upset portions 49 retain the termi nals against axial displacement with respect to bracket 16.

It will be apparent that the high voltage producing apparatus can be assembled in combination with the chassis, the terminals 17 and soldered connections made before said apparatus is enclosed by the cowling members 11 and 31. Should an occasion arise wherein replacement of some part of the high voltage producing apparatus is necessary, the same may conveniently be effected by unbolting the cowling and removing it from the chassis 8 without the necessity of first breaking soldered connections.

In order that the prongs 17 may cooperate with the sockets 19, the cover member 31 has an aperture 51 therein through which the element 13 is adapted to extend when the member 31 is in its normal or closed position. The aperture 51, however, is in a rectangular ofiset region 52, of member 31, which is distended outward to accommodate outwardly protruding portions of the mechanism just referred to.

Although the clampingaction of screws 26 are adequate to retain the terminals 17 and 19 in operative engagement with each other, additional means, if desired, may also be used to retain the terminals in engagement with each other. The additional means may take the form of a screw 53' adapted to pass freely through a hole 56 in the outer cowling and be threaded in a second hole 54 in the cover 31. While cover 31 is so disposed, its swingable end may be further retained in closed relationship with respect to the housing 1-1 by a resilient clasp or hook 57 on the end of said cover, the clasp being, adapted to snap down over the rear of housing 11 as cover 31 is closed.

In the operation of withdrawing the terminal plug 13 from engagement with the terminal socket 214, there is a tendency to bend the bracket 16 outwardly owing to the retentive engagement of the pins 17 by the sockets 19. This tendency is resisted because the carrier portion 37 includes a pair of offset ears 53 that extend behind the flanges 29, flanges 29 thus limifing' deflection of bracket 16 outwardly of housing 11,

As will now be apparent, it is impossible to gain access to the high voltage producing apparatus without swinging the cover 31 to a substantial degree, about its pivot axis 34, from the normal position of said cover. The operation of swinging the cover can be carried out only after the plug and socket 17 and 19 have been disengaged from each other. This precludes the possibility of access to the space within the cowling members 11 and 31 by merely removing enough of the screws 26 to enable the wall 7 to be bent away from one corner of the cabinet.

Although I have thus described my invention, I am also aware that numerous and extensive departures may be made therefrom without departing from the spirit or scope of my invention.

If the cover is opened inadvertently or intentionally, the act of opening stops the plug from the socket and disconnects the power line. Furthermore, even if the rivets that hold the plug onto the rear wall should be removed so that removal of the wall does not remove the plug, there is still the element of safety due to the fact that the cover engages the plug and stops it from the socket.

I claim:

1. The combination with television equipment housed in a cabinet one of the sides of which is open and the equipment includes a frame for support of high voltage producing apparatus collectively enveloped by movable and fixed inner cowl members within the cabinet, of a first pair of terminals, bracket means on the frame to sup port the terminals independently of said Cowling and in electrical communication with the high voltage producing apparatus, an outer cowl member to at least partly close the open side of the cabinet, said outer cowl member when closing the cabinet being adapted to lock the movable cowl member against opening, a second pair of terminals carried by the outer Cowling at the end of a supply cable, said second pair of terminals being adapted to extend into electrical communication with the first pair of terminals when the opening is closed by the outer cowl member, opening of said inner cowl thereby being possible only after said outer cowl has been removed from the cabinet and one of the pairs of terminals concurrently disengaged from the other pair of terminals, first stop means in connection with said bracket means, and second step means in connection with the fixed inner cowl member, said respective stop means being adapted to cooperate with each other when one of the pair of terminals is disengaged from the other pair of terminals to resist permanent deflection of said bracket means.

2. The combination with television equipment housed in a cabinet one of the sides of which is open and the equipment includes a frame for support of high voltage producing apparatus collectively enveloped by movable and fixed inner cowl members within the cabinet, of pivotal means to pivotally anchor the movable cowl member to the fixed cowl member, a first pair of terminals, bracket means on the frame to support the terminals independently of said cowling, said terminals being in electrical communication with the high voltage producing apparatus while so supported, an outer cowl member to at least partly close the open side of the cabinet, said outer cowl member when closing the cabinet being adapted to lock the movable cowl member against rotation to an open position, a second pair of terminals carried by the outer cowl member at the end of a supply cable, said second pair of terminals being adapted to extend into electrical communication with the first pair of terminals when the opening is closed by the outer cowl member, opening of said inner cowl thereby being possible only after said outer cowl has been removed from the cabinet and one of the pairs of terminals concurrently disengaged from the other pair of terminals, first stop means in connection with said bracket means, and second stop means in connection with the fixed inner cowl member, said respective stop means being adapted to cooperate with each other when one of the pair of terminals is disengaged from the other pair of terminals to resist permanent deflection of said bracket means.

3. The combination with television equipment housed in a cabinet one of the sides of which is open and the equipment includes a frame for support of high voltage producing apparatus collectively enveloped by movable and fixed inner cowl members within the cabinet, of pivotal means to pivotally anchor the movable cowl member to the fixed cowl member, latch means on said movable cowl member to releasably secure said movable cowl member to said frame, a first pair of terminals, bracket means on the frame to support the terminals independently of said cowling, said terminals being in electrical communication with the high voltage producing apparatus while so supported, an outer cowl member to at least partly close the open side of the cabinet, said outer cowl member when closing the cabinet being adapted to lock the movable cowl member against rotation to an open position, a second pair of terminals carried by the outer cowl member at the end of a supply cable, said second pair of terminals being adapted to extend into electrical communication with the first pair of terminals when the opening is closed by the outer cowl member, opening of said inner cowl thereby being possible only after said outer cowl has been removed from the cabinet and one of the pairs of terminals concurrently disengaged from the other pair of terminals, first stop means in connection with said bracket means, and second stop means in connection with the fixed inner cowl member, said respective stop means being adapted to cooperate with each other when one of the pair of terminals is disengaged from the other pair of terminals to resist permanent deflection of said bracket means.

References Cited in the file of this patent UNITED STATES PATENTS 1,071,797 Roche Sept. 2, 1913 2,439,708 Abraham Apr. 13, 1948 2,497,487 Cain Feb. 14, 1950 FOREIGN PATENTS 561,831 Germany Oct. 20, 1932 469,289 Great Britain July 22, 1937

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