US2093739A - Electric circuit controlling appliance - Google Patents

Description

Sept. 21, 1937. .1. SACHS ELECTRIC CIRCUIT CONTROLLING APPLIANCE Filed April 13, 1935 2 Sheets-Sheet l J27 vent or N 5705510. @c/zs fiyij, Z:

14 Z: arngr Sept. 21, 1937. J. sAcHs ELECTRIC CIRCUIT CONTROLLING APPLIANCE Filed April 13, 1935 2 Sheets-Sheet 2 Patented Sept. 21, 1937 2,093,739

UNITED STATES PATENT OFFICE ELECTRIC CIRCUIT CONTROLLING APPLIANCE Joseph Sachs, West Hartford, Conn.

Application April 13, 1935, Serial No. 16,133

16 Claims. (01. 20050) The invention relates particularly to an eleclimiting the scope of the invention, the claims tric circuit controlling appliance which includes forming a part of this specification being relied fuse contacts and fuses in at least two legs or sides upon for that purpose.

of the circuit, and which is primarily adapted and Of the drawings: intended to be used in an electric circuit ahead of Fig. 1 is a front view of an electric circuit con- 5 the meter therein. trolling appliance embodying the invention.

In order to obtain current in a three wire sys- Fig. 2 is a view similar to Fig. 1 but showing tem without the current being measured by the the switch handle in its open-circuit position meter, it has been a prevalent practice to remove and showing the sliding fuse cover in its open po- 0 one of the fuses ahead of the meter, or to intensition. In this view certain parts are broken away tionally blow one of the fuses, and to then place a to show other parts more clearly.

jumper or by -pass in engagement with the fuse Fig. 3 is a vertical sectional view taken along contacts so as to make a transverse electrical the line 33 of Fig. 1. connection from one side of the circuit to the Fig. 4 is a horizontal sectional view taken 1 other side. In this way both sides of the load ciralong the lines 44 of Figs. 1 and 3.

cuit are connected with one side of the supply cir- Referring to the drawings, l represents a stacuit and the user obtains current for this entire tionary insulating base, on the front of which load; but inasmuch as the connection from the are two pairs of fuse receiving contacts 2, 2 and other side of the supply circuit to the meter is 3, 3, the contacts of the two pairs being spaced broken, the meter does not operate. apart transversely. The fuse contacts 2, 2 and 20 One of the principal objects of the present in- 3, 3 are shown as being adapted for receiving vention is to provide an electric circuit controlling a fuse of the knife blade type, but it will be underappliance which includes two fuses in two legs of stood that the invention is not necessarily so the circuit, and which has, in conjunction with the limited. fuses, a sliding cover and associated parts which Associated with the base I and the fuse con- 5 serve when the cover is closed to prevent the tacts 2, 2 and 3, 3 is a cover 4 which is mounted maintenance of any transverse electrical connecto slide longitudinally in a plane parallel with the tions, this being accomplished by providing an front of the base. When the cover is in its closed element on the cover which directly interferes position, as shown in Fig. 1, the fuse contacts and 70 with any such transverse electrical connection the fuses therein are entirely enclosed and produring closing or attempted closing of the cover. tected, and when the cover is in its open position, Preferably the said element on the cover is a lonas shown in Fig. 2, the fuse contacts and the fuses gitudinal shield which cooperates with the base therein are readily accessible. when the cover is fully closed so as to eliminate In order to prevent the maintenance of any 5 any transverse opening or passage between one transverse electrical connection between the fuse pair of fuse contacts or the fuse therein and the contacts of one pair and the fuse contacts of the other pair of fuse contacts or the fuse therein. other pair, I provide an element such as 5 pro- Preferably, a circuit controlling appliance emjecting rearward from the cover and movable bodying the invention includes switching means longitudinally between the two pairs of fuse con- 410 in series with the fuses; and when switching tacts and the fuses therein, while the cover is'be- 40 means are provided I prefer to provide an intering moved in the closing direction. When the locking mechanism which prevents the sliding sliding cover 4 is moved from its open position tocover from being opened when the switch is closed ward its closed position the element 5 moves longiand which prevents the switch from being closed tudinally, and if any wire or other transverse elecwhen the sliding cover is open. trical connection has been put in place from a fuse A further object of the invention is to provide contact of one pair to a fuse contact of the other an improved interlocking means between a sliding pair this wire is either detached or broken by the the fuse cover and a switch operating handle. moving element 5 or the wire serves to prevent Other objects of the invention will be apparent movement of the element and thus prevent closing 5-0 from the following specification and claims. of the cover. In the accompanying drawings I have shown The details of the rearward projecting elethe embodiment of the invention which I now ment '5 may be widely varied, but preferably and deem preferable, but it will be understood that the as shown it is in the form of a longitudinal shield drawings are intended for illustrative purposes which is movable between the two pairs of fuse only and are not to be construed as defining .or contacts. This shield overlaps a portion of the base and preferably enters a groove 6 formed in the base, as shown in Figs. 2 and i. Preferably and as shown, the base is provided with an integral barrier 'i which projects forward from the main body of the base and is positioned between the fuse contacts of the two pairs; and the beforementioned groove 6 is formed in the barrier I.

The sliding element for interfering with the transverse wire or connection is distinctly different in its action from pivoted shields which have heretofore been proposed to be used. A pivoted shield merely serves to press a transverse conductor or connection firmly against the base but it has no tendency whatever to break or detach the said connection or conductor. Furthermore, with a pivoted shield carried by a pivoted cover there is nothing to prevent the substantial closing of the cover notwithstanding the presence of an unbroken or undetached transverse connection between the fuses'or their contacts. Unless the parts areconstructed and fitted much more accurately than is customary or practicable in the manufacture of switches, the presence of a thin transverse conductor will not interfere with the closing of a pivoted cover. However, with the sliding cover and the sliding projecting element there is an actual interference between the element and the transverse connection which definitely and unavoidably results either in the detachment or breaking of the connection or in the blocking of the projecting element so that the cover cannot be closed.

When the cover is entirely closed the overlapping means, consisting of the shield 5 and the barrier 1 with its groove 6, completely eliminate any transverse opening or passage between the one pair of fuse contacts or the fuse therein and the other pair of fuse contacts or the fuse therein. It will be apparent from the drawings that the shield approximately fits the groove, thus making it impossible for even a very small wire to lie between the overlapping surfaces.

Preferably, the base I is at least partly enclosed in a suitable casing or box such as 8. The box 8 has a front wall or cover 9 having an opening therein, and the fuse contacts and fuses are accessible at the said opening. Preferably and as shown, the base I has a front portion It which projects through and substantially closes theopening in the front wall 9. This front portion I ii may have peripheral walls which, together with the barrier I, entirely surround the fuse contacts and the fuses at the sides and ends thereof.

The slidable cover i is carried by the front wall 9 of the box and is offset toward the front and is shaped to pass in front of the fuse contacts and the fuses and in front of the forward projectingportion of the base, as clearly indicated in Fig. i. As shown, the cover 4 has laterally projecting flanges I I and I2 at its edges which are engaged and guided by suitable guiding means secured to the said front wall 9. It will be observed that the shield 5 carried by the cover 4 is in front of the plane of the front wall or cover 9 of the box, and that the said shield is movable in front of the said front wall or cover. When the cover 3 is offset toward the front, as shown,'the forward projecting portion is closed at the bottom by a transverse wall I3, and the lower end of the shield 5 engages the said wall. The upper end of the shield preferably projects beyond the upper end of the cover. Preferably, forwardprojecting transverse partitions are provided on the front wall of the box adjacent the opposite top and bottom edges of the opening therein. The upper partition is shown at I4 and is provided with a downward extending flange I 4 which surrounds and encloses the upper end of the cover t when the cover is in closed position, as shown in Fig. 1. The partition I4 is provided with a slot through which the upper end of the shield 5 projects. The lower partition is shown at I5, this being immediately adjacent the cover wall I3 when the cover is in closed position. The partition I5 has a slot therein through which the shield 5 extends.

Preferably, a switching means is associated with the fuse contacts and the fuses, and one suitable form of switching means is shown in the drawings, although the invention is not limited to the particular switching means disclosed.

As shown, two transversely extending insulating blocks I6 and I? are secured to the rear wall of the box I. Mounted on the block I 6 are two forward projecting transversely spaced conducting brackets I8 and I9 which partly support the fuse base I and which are electrically connected with the lower fuse contacts 2 and 3. Electrical connections between the fuse contacts and the respective brackets I8 and I9 are established by means of conducting straps 26, 20 and screws 2i, 2|. The screws 2i, 2i not only insure the electrical connections but they also serve to mechanically connect the base I with the brackets.

Also secured to the insulating block I6 and spaced transversely from the brackets I8 and I9 are forward projecting conducting straps 22 and 23. Wire terminals 26 and 25 are connected respectively to the straps 22 and 23. Mounted upon and electrically connected with the several straps and brackets are pairs of stationary switch contacts 26, 27 and 28, 29. For making and breaking electrical connection between the switch contacts of the respective pairs there are provided movable switching members each consisting of a flat insulating plate 3% and a conducting elementtl carried thereby and having contact surfaces at opposite sides of the plate, these opposite contact surfaces being adapted to engage the corresponding stationary contacts. Each plate 38 is perpendicular to the front surface of the block I6 and to the rear surface of the fuse base I, and it is guided by the said surfaces for rectilinear movement upward or downward parallel with the rear wall of the enclosing box. In order that the plate may be additionally guided, it is preferably provided with a rearward projection 30* which directly engages with the rear Wall of the box. For operating the switching members there is provided a pivoted crank or bail 32 which is mounted in the side walls of the box and which is provided with an operating handle 33 on the exterior of the box at one side thereof, preferably the right side. The crank extends through slots 39 in the insulating plates 38.

Mounted on the upper insulating block I1 are two forward projecting transversely spaced conducting brackets 34 which also partly support the fuse base I and which are electrically connected with the upper fuse contacts 2 and 5%. Electrical connections between the fuse contacts and the respective brackets 36 are established by means of conducting straps 35, 35 and screws 36, 36. The screws 36, 36 not only insure the electrical connections but they also serve to mechanically connect the base I with the brackets a l. Electrically connected with the brackets 3 are wire terminals 31.

When the handle 33 is in the upper position shown in Fig. 3, the switching members are held in the position shown by full lines in the same figure, and electrical connection is established between the stationary switch contacts of each pair, thus electrically connecting the wire terminals 24 and 25 with the lower fuse contacts 2 and 3. When the handle is moved downward to the lower position shown in Fig. 3, the switching members are moved upward to the position shown by dotted lines in the same figure, thus breaking the electrical connection between the stationary switch contacts of each pair. Thus by operating the handle 33 and closing and opening the switch, electrical connection can be established or broken between the wire terminals 24 and 25 at the bottom and the wire terminals 31 at the top.

Preferably, wire terminals 38, 38 are provided for the connection of neutral wires. These terminals may be mounted on a projection 39 on the lower insulating block 16.

Preferably, an interlocking mechanism is provided which positively prevents the cover 4 from being moved to open position when the switch handle is in closed-circuit position and which positively prevents the switch handle from being moved to closed-circuit position when the cover is in open position. So far as the broader aspects of the invention are concerned, I do not limit myself to any particular form of interlocking mechanism; but preferably and in accordance with a more specific phase of the invention the interlocking mechanism is constructed as shown and in accordance with the following description.

Supported on the front wall of the box is an interlock plate 40 which is movable laterally into a projecting position, as shown in Fig. 2, wherein it holds the handle 33 in open-circuit position, or into a non-projecting position, as shown in Fig. l, in which position it is positively held by the handle 33 when the latter is in closed-circuit position. Preferably, the plate 40 is mounted for pivotal movement about a pivot stud at 4|.

Co-acting means are provided on the interlock plate 40 and on the slidable cover 4 whereby the plate is automatically moved to its projecting position when the cover is moved to open position and whereby the plate is automatically moved to its non-projecting position when the cover is moved to its closed position. Preferably, this coacting means is of the cam-and-follower type, as shown. The flange l2 of the cover 4 is provided with a laterally projecting wing l2 which is behind the interlock plate 40 and which carries a forward projecting stud 42. The plate 40 is provided with a cam slot 43 through which the stud 42 extends. The main portion of the slot 43 is so located as to be parallel with the direction of movement of the slide 4 and of the stud 42 when the said plate 40 is in its projecting position. The cam slot 43 has another portion 43 which is at an angle to the said first portion, as clearly shown in Figs. 1 and 2. Preferably, a plate 44 is provided which is secured to the front wall 9 of the box and which is positioned in front of the interlock plate 40. As shown, this front plate 44 has a slot 45 therein through which the stud 42 projects.

With the cover 4 in its lower or open position, as shown in Fig. 2, the interlock plate 40 is in its projecting position and the stud 42 is at the lower end of the cam slot 43. As the cover is moved upward toward its closed position the stud 42 travels along the main parallel portion of the slot 43, the plate 40 remaining in its projecting position. When the cover has nearly reached its fully closed position, preferably having entered the flange M, the stud 42 enters the short angular portion 43 of the cam slot, thus moving the plate 40 laterally from its projecting position, as shown in Fig. 2, to its non-projecting position, as shown in Fig. 1. When the cover is moved in the opposite direction from its closed position to its open position the movement of the plate 40 is opposite to that described.

It will be apparent that, with the cover in its lower position, as shown in Fig. 2, and with the interlock plate in its projecting position, the handle 33 cannot be moved upward to close the circuit. With the cover in its closed position, as shown in Fig. 1, and with the interlock plate in its non-projecting position, the handle 33 can be moved upward to close the circuit; but when it is in its upper circuit-closing position the interlock plate 40 cannot be moved laterally to its projecting position and hence the cover cannot be moved downward to expose the fuses or the fuse contacts.

I have already described in detail the action of the overlapping parts on the cover 4 and on the base I in preventing the maintenance of any transverse electrical connection from one side of the circuit to the other when the cover is closed. It will be obvious that these parts cooperate directly with the switch and the interlocking mechanism which have now been fully described, With the switch open and with the cover open, a transverse electrical connection can easily be put in place from the fuse or fuse contacts at one side to the fuse or fuse contacts at the other side; but inasmuch as the switch is open such transverse electrical connection would be entirely without function. It is impossible to close the switch unless the cover has first been closed, but as already explained, the cover cannot be closed with a transverse electrical connection in place. Either the transverse electrical connection is broken by the closing of the cover or the said transverse connection entirely prevents the cover from being closed. If the transverse connection is broken by the closing of the cover, the intended theft of current is defeated; or if the transverse connection prevents the cover from being closed, the switch necessarily remains open and the customer can obtain no current at all.

What I claim is:

1. In a device of the class described, the combination of an insulating base, two pairs of fuse receiving contacts on the front of the base and spaced apart transversely, a cover for the fuse contacts and for fuses therein which cover is mounted to slide independently of the fuse contacts and the fuses longitudinally in a plane parallel with the front of the base, and an element projecting rearward from the cover and movable between the two pairs of fuse contacts and the fuses therein while the cover is being moved in the closing direction, the said rearward projecting element during the said movement cooperating with the base so as to directly interfere with any transverse electrical connection between one pair of fuse contacts or the fuse therein and the other pair of fuse contacts or the fuse therein with the result that the said connection is broken or detached or that the cover is prevented from closing.

2. In a device of the class described, the combination of an insulating base, two pairs of fuse receiving contacts on the front of the base and spaced apart transversely, a cover for the fuse between one pair of fuse contacts or the fuse therein and the other pair of fuse contacts or the fuse therein.

9. The combination of an enclosing box having an opening in the front wall thereof, an insulating base having a front portion projecting through and substantially closing the front opening in the box, the said projecting portion of the base including a longitudinal barrier, two pairs of fuse receiving contacts positioned on the projecting portion of the base at opposite sides of the said barrier, a longitudinally slidable cover mounted on the front of the box and shaped to pass in front of the barrier and the fuse contacts and in front of fuses in said contacts, and a shield carried by the cover at the rear thereof and movable in front of the front wall of the box, the said shield overlapping the barrier and serving when the cover is closed to prevent the maintenance of any electrical connection between the fuse contacts and fuses at opposite sides of the barrier.

10. The combination of an enclosing box having an opening in the front wall thereof, an insulating base having a front portion projecting through and substantially closing the front opening in the box, the said projecting portion of the base including a longitudinal barrier having a longitudinal slot therein, two pairs of fuse receiving contacts positioned on the projecting portion of the base at opposite sides of the said barrier, a longitudinally slidable cover mounted on the front of the box and shaped to pass in front ,of the barrier and the fuse contacts and in front of fuses in said contacts, and a shield carried by the cover at the rear thereof and movable in front of the front wall of the box, the said shield entering the slot in the barrier and serving when the cover is closed to prevent the maintenance of any electrical connection between the fuse contacts and fuses at opposite sides of the barrier.

11. The combination of an enclosing box having an opening in the front wall thereof, forward projecting transverse partitions on the front wall adjacent opposite edges of the opening therein which partitions have slots therein, an insulating base having a front portion projecting through and substantially closing the front opening in the box, two pairs of fuse receiving contacts positioned on the projecting portion of the base and spaced apart transversely, a longitudinally slidable cover mounted on the front of the box and shaped to pass in front of the fuse contacts and in front of fuses in said contacts, and a shield carried by the cover at the rear thereof and movable in front of the front wall of the box and through the slots in the partitions, the said shield being between the two pairs of fuse contacts and the fuses therein when the cover is in closed position and the said shield directly cooperating with the base to prevent the maintenance of any electrical connection between one pair of fuse contacts or the fuse therein and the other pair of fuse contacts or the fuse therein.

12. In a fused electric switch, the combination of an insulating base, two pairs of fuse receiving contacts on the front of the base and spaced apart transversely, two stationary switch contacts electrically connected respectively with one fuse contact of each pair, movable switching means associated with the stationary contacts to open and close the circuit, a cover for the fuse contacts and for fuses therein which cover is mounted to slide longitudinally in a plane parallel with the front of the base, interlocking means preventing movement of the switching means to closed circuit position when the cover is in open position and preventing movement of the cover to open position when the switching means is in closed circuit position, and an element projecting rearward from the cover and movable between the two pairs of fuse contacts and the fuses therein while the cover is being moved in the closing direction, the said rearward projecting element during the said movement cooperating with the base so as to directly interfere with any transverse electrical connection between one pair of fuse contacts or the fuse therein and the other pair of contacts or the fuse therein with the result that the said connection is broken or detached or that the cover is prevented from closing.

13. In a fused electric switch, the combination of an insulating base, two pairs of fuse receiving contacts on the front of the base and spaced apart transversely, two stationary switch contacts electrically connected respectively with one fuse contact of each pair; movable switching means associated with the stationary contacts to open and close the circuit, a cover for the fuse contacts and for fuses therein which cover is mounted to slide longitudinally in a plane parallel with the front of the base, interlocking means preventing movement of the switching means to closed circuit position when the cover is in open position and preventing movement of the cover to open position when the switching means is in closed circuit position, and cooperating means on the slidable cover and on the stationary base which overlap each other when the cover is in closed position so as to eliminate any transverse opening or passage between one pair of fuse contacts or the fuse therein and the other pair of fuse contacts or the fuse therein.

14. The combination of an enclosing box having an opening in the front wall thereof, an insulating base having a front portion projecting through and substantially closing the front opening in the box, two pairs of fuse receiving contacts positioned on the projecting portion of the base and spaced apart transversely, stationary switch contacts electrically connected respectively with one fuse contact of each pair, movable switching means associated with the stationary contacts to open and close the circuit, a longitudinally slidable cover mounted on the front of the box and shaped to pass in front of the fuse contacts and in front of fuses in said contacts, interlocking means preventing movement of the switching means to closed circuit position when the cover is in open position and preventing movement of the cover to open position when the switching means is in closed circuit position, and a shield carried by the cover at the rear thereof and movable in front of the front wall of the box, the said shield being between the two pairs of fuse contacts and the fuses therein when the cover is in closed position and directly cooperating with the base to prevent the maintenance of any electrical connection between one pair of fuse contacts or the fuse therein and the other pair of fuse contacts or the fuse therein.

15. In a fused electric switch, the combination of an enclosing box having an opening in the front wall thereof, fuse receiving contacts positioned to be accessible at the said opening, switching means in the box electrically connected with the fuse contacts and adapted to open and close the circuit, a handle at one side of the box for operating the said switching means, a slidable cover for the fuse contacts and for fuses therein, means for guiding the cover for longitudinal movement and for preventing lateral movement thereof, a plate pivotall; supported on the front wall of the box at the front of the said wall and movable laterally into a projecting position wherein it holds the handle in open-circuit position or into a non-projecting position in which it is positively held by the handle when the latter is in closed-circuit position, and coacting camand-follower means on the plate and on the slidable cover whereby the plate is automatically moved. about its pivotal axis to its projecting position when the cover is moved to open position and whereby the plate is automatically moved about its pivotal axis to its non-projecting position when the cover is moved to closed position.

16. In a fused electric switch, the combination of an enclosing box having an opening in the front wall thereof, fuse receiving contacts positioned to be accessible at the said opening, switching means in the box electrically connected with the fuse contacts and adapted to open and close slidable cover entering the to automatically move the plate to its projecting the circuit, a handle at one side of the box for operating the said switching means, a slidable cover for the fuse contacts and for fuses therein, means for guiding the cover for longitudinal movement and for preventing lateral movement thereof, a plate pivoted to the front wall of the box and movable laterally into a projecting position wherein it holds the handle in open-circuit position or into a non-projecting position in which it is positively held by the handle when the latter is in closed-circuit position, the said plate having a cam slot therein one portion of which is parallel with direction of cover movement when the plate is in projecting position and another portion of which is at an angle to the first said portion, and a follower stud on the cam slot and serving position when the cover is moved to open position and serving to automatically move the plate to its non-projecting position when the cover is moved to closed position.

JOSEPH SACHS.

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