US2105169A - Safety switch box - Google Patents

Description

Jan. 11,1938. w. F. SUTHERLIN Y 2,105,169

SAFETY SWITCH BOX Original Filed Deo. 26, 1935 2 Sheets-Sheet l ATTORNEY:

Jan. 11, 1938. w. F. SUTHERLIN SAFETY SWITCH BOX 2 Sheets-Sheet 2 Original Filed Dec. 26, l19255 .W Sw@ www F 5U #wf/n ATTORNEYJ Patented Jan. ll, 1938 UNiTED STATES SAFETY SWITCH BOX Waiter F. Seibel-lin, Birmingham, Ala., assigner of one-half to G. J. .Iehelea Birmingham, Ala.

@riginai application December 26, 1935, Serial Divided and this application December 19, i936, Serial No. 116,728

3 Claims.

This application is a division of my application Serial No. 56,194, filed December 26, 1935.

This invention relates to switch boxes, and has for an object the provision of a switch box which 5.,; will prevent the stealing of electric current or the jumping of meters so as to obtain electric current without the current passing through the meter.

Another object of the invention is to provide a short circuiting device in` the switch box, which,

when the main switch is open, automatically short circuits the work circuits.

' Another object oi' the invention is to provide a door giving access to the main fuse in the switch 1cox, and an automatic locking means therefor, barring access 'to the fuse without opening the switch.

Another object of the invention is to provide a safety switch box with means for locking the switch in open position, as when premises are unoccupied, to prevent the unauthorized closing of the switch.

' Another object of the invention is the provision of a toggle make and break main switch so arranged that the work circuits are short circuitecl whenv the main switch open.

A still further object of the invention is to provide a means for detachably mounting a meter on the switch box which may only be removed when the switch box is unlocked and opened, thereby preventing wiring around the meter.

l As is well known, numerous devices are employed for stealing current from an electric lighting company by unscrupulous persons. Where the meter is separate from the switch box, de-

vices are employed for wiring around the meter so that a part, if not all, of the current used passes around the meter instead of going through it. Also, where a building has been unoccupied, some people have defrauded the lighting company by closing the main switch in the switch box and connecting up the electric current without notiiying the lighting company. It has also been known to run wires from adjoining sources around the meter to connect with the work circuits so that no current can pass through the meter. It has also been known to ground the work circuit in some concealed place and to connect the ground wire to the meter in such a way that it would not be observed and so that no current passes into the potential coil of the meter, theremeter, I provide a means for detachably mounting the meter on the switch box so that no connections between the switch box and the meter are accessible. The meter may be readily removed, when desired, by authorized persons, by unlocking the switch box, whereby access to the fastening means may be obtained. I also provide a means whereby the switch may be locked in open position when the premises are vacated, thereby preventing unauthorized closing oi the main switch. In order to prevent wiring around the meter from an outside source and thereby obtaining electric current, I provide a short circuiting device within the switch box, operable when the main switch is open, which short circuits the work circuits so that no current can pass into the work circuits until the main switch is closed.

Apparatus embodying features of my invention is illustrated in the accompanying drawings formd ing a part of this application, in which Fig. 1 is a plan View of my improved switch box with the meter in place thereon;

Fig. 2 is a sectional View taken along the line '1I-II of Fig. 1;

Fig. 3 is a back view of the switch box;

Fig. 4 is a front View of th-e switch box and meter with the switch box cover removed and showing the electric connections Fig. 5 is a diagrammatic View showing the means whereby the work circuits are short circuited and grounded when the main switch is open; and

Fig. 6 is a fragmentary detail view showing the means for locking the switch box door.

Referring to the drawings, my improved switch box comprises ends IIJ and II, a bottom I2, and sides I3 and I4. A cover E6 is hinged to the side I3, by hinges II, and may be held closed by means of a padlock I 8, having its fastening element passing through a staple 2li extending through the cover I6 from the side of the switch box.

The bottom I 2 is extended upwardly at the rear, as shown at I9, to support a meter 2I. The meter 2I is supported on the extension I9 by means of button head rivets 22 on the back of the meter, which are Ypassed through suitable openings 23 and into slots 24. Moving the meter downwardly with the rivets 22 in the slots 24, fixes it securely on the extension I9.

Within the switch box is mounted a fuse block 2S made of insulating material, which carries the main fuse 2'I. As shown in Figs. 2 and 4 of the drawings, the meter 2| is connected electrically to the switch box by means of prongs 29 which extend downwardly into suitable sockets 3| provided in the fuse block 26, there being corresponding openings 35 in the end of the switch box to allow the prongs to enter the sockets. The line circuit connections are at 32 the ground connections to the meter at 33. The fuse 21, as shown in Fig. 2 of the drawings, is surrounded by a housing 3U which prevents access to the switch 28 and electrical connections around the fuse.

Extending across the upper end of the fuse block 26 is a bar 3.4. Carried by the meter, on each side thereof, is a resilient latch member 86 having on its lower end a hook 31 which engages automatically with the bar 34 when the meter is mounted on the extension I9 as described. The hooks 31 may be disengaged from the bar 34 only when the door |6 is unlocked and open. Access may then be had to the hooks 3l to press them rearwardly and disengage them from the bar 34 for the purpose of removing the meter.

The main switch 28, as shown in Fig. 2 of the drawings, is mounted upon the fuse block 26 and is connected to the line 38 at 39. When the main switch is closed, as shown in Fig. 2 of the drawings, the line passes through the switch to the main fuse 21 and from thence through a connection 4| to the meter connection 32. The main switch 28, as shown in Fig. 2, comprises a bar 42 which serves to connect the line to the meter, as just described, when the switch is closed.

Mounted upon the bar 42 is a plate of insulating material 43 having a slot 44 therein. The switch is opened and closed by means of a. bell crank lever 48 extending across the box and movable in the slot 44 by means of a handle fi? extending outside the box. The Switch is biased to closed position or open position by means of a spring 48, connected to the plate and to the bottom of `the box, as shown.

Carried by the plate 43 on the opposite side from the main switch bar 42 is a bar 49 of conducting material so disposed that when the main switch is thrown to open position, it serves to connect a plurality of terminals l and short circuit the electrical connections made thereto. When thrown to open position the spring 48 serves to draw the bar 49 down tightly against the terminals 5|. It will thus be seen that the switch 28 can not be thrown to open the main circuit without short circuiting across the terminals 5|, nor can it be thrown to a position to raise the bar off the terminals 5| without closing the main switch by reason of the spring 48. The handle 41 is provided with a, link 52 which, when the main switch is open, may be swung to a position to be engaged by the lock i8 when the main switch 28 is opened. The main switch may thus be locked in open position by means of the lock |8, which serves to close the switch box. By this means, unauthorized closing of the switch is prevented.

As is customary in switch boxes, access to the main fuse 21 is had by means of a small spring pressed door 53. On the under side of the door 53 is provided a strap 54 through which a bolt 55 passes. The bolt 56 is actuated by means of a pin 58 extending inwardly of the box in the path of the switch lever 46, so that when the switch 28 is thrown to closed position, as shown in Fig. 2, the lever 46 strikes the pin 58 and moves the bolt 56 into locking position. When the switch 28 is opened, the bolt 56 falls by gravity to disengage it from the strap 54. By this arrangement it is necessary, in order to gain access to the main fuse 21, to open the main switch 28.

Within the switch box is located a ground strip of conducting material 59, which ground strip is connected, as shown in Fig. 4, to any suitable ground connection, as shown at 6|. One of the terminals 5| is connected to the ground strip 59 within the box by means of a connection 62 so that when the main switch is thrown to open position with the conducting bar 49 across the terminals 5|, all circuits leading thereto are grounded. It is also preferable that one of the terminals 5| also be connected directly to the ground outside the box, as shown in the drawing.

Referring now to Fig. 5, I show diagrammatically the operation of the short circuiting feature of my invention. The line circuit is shown at 38 and passes through the switch bar 42, when the switch is in closed position, thence through the main fuse 21 and meter 2|. From the meter 2|, the circuit continues through a, connection 64 and house fuse 66 to a work circuit 61, thence through a light or other current consuming device 68. From the current consuming device the current continues through a house fuse 69 to the ground strip 5S, and from thence back through the meter 2| to the return line 1|.

In accordance with my invention, I connect a conductor 12 to the work circuit beyond the fuse 66, and from thence to one of the terminals 5| in the switch box. The other terminal 5| being connected directly to the ground, it will be seen that the work circuit, when the switch 28 is in open position, as shown in Fig. 5, is connected directly to the ground. If any attempt be made to obtain current without passing the current through the meter, it will be seen that the conductor 49 serves to short circuit the work circuit so that no current can be obtained.

From the foregoing, it will be apparent that I have devised an improved switch box which is simple and economical of manufacture, and which is adapted to prevent theft of current. The mounting of the meter on the switch box with the prong and socket connections prevents tampering with the connections between the meter and the switch box, while the means for locking the meter on to the switch box prevents its unauthorized removal for the purpose of tampering with the connections. The means provided for locking the switch in open position prevents unauthorized closing of the switch where previously unoccupied premises become occupied. The short circuiting device incorporated in the switch box insures that if wiring from an outside source is carried in around the meter no current can be obtained, because the work circuits are automatically grounded.

While I have shown my invention in but one form, it will be obvious to those skilled in the art that it is not so limited, but is susceptible of various changes and modifications, without departing from the spirit thereof, and I desire, therefore, that only such limitations shall be placed thereupon as are imposed by the prior art or as are specifically set forth in the appended claims.

What I claim is:

1. A switch apparatus comprising a switch box,

a door for the switch box and a lock therefor, meter connections in the switch box terminating in sockets in the upper part of the box, a meter mounted on the top of the box, prongs carried by the meter tting into the sockets, there being corresponding openings in the upper end of the box to permit the prongs to enter the sockets, a bar extending across inside the switch box, and resilient latch members carried by the meter and engaging the bar when the meter is mounted on the box.

2. In switch apparatus of the character described, a switch box having an end wall with a plurality of openings therein, a door on the switch box, a meter mounted on the switch box, spring pressed latch means carried by the meter and extending through the openings in the end wall,

and a latch bar inside the box for engaging the spring pressed latch means.

3. In switch apparatus of the character described, a switch box, terminals for meter connections in the switch box terminating in sockets in the upper end thereof, an end wall for the switch box having a plurality of openings therein, a meter mounted on the upper end of the switch box, prongs on the meter extending through some of the openings in to the sockets, a bar extending across inside the upper end of the box, resilient latches on the meter having wedge shaped ends with hooks to engage the bar, said latches being adapted to pass through the openings in said box when the meter is mounted thereon, and a door for the box giving access to the latches.

WALTER F. SUTHERLIN.

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