US 2128647 A
Description (OCR text may contain errors)
I938. E. G. JOHANSSON 2,123,647
I COMBINATION FUSED SWITCH I Filed Dec. 6, 1955 2 Sheets-Sheet 1 Q Zwzzir 2/ 5 W12 file/220% a d ,1 E. G. JOHANSSON 2,128,647
COMBINATION FUSED SWITCH \H n I I W "/4 f, g i Wag/whamm- Cal Patented Aug. 30, 1938 UNITED STATES 2,128,641 7 COMBINATION FUSED swrrcn Ernest G. J ohansson,
Watertown, Mass, as-
signor to The Palmer Electric & Manufacturing 00., Waltham, Mesa, a corporation of Massachusetts Application December 6, 1935, Serial No. 53,168
This invention relates to a fused electric switch in a casing or cabinet, having a door or doors which, when closed, tightly close the casing without overlapping'the exterior of the casing walls and which, when wide open, do not overlap any portion of the area bounded by the side walls of the casing.
Devices of this character are in some instances installed in multiple units with the side or end walls closely adjacent or actually abutting each other, and in other instances are individually embedded in a plastered wall and supplied with an apron or trim to conceal the joints between the cabinet and the wall. To efiect economies in space in the installation of the devices in multiple or to permit the installation of the apron or trim when the cabinet has been embedded in a plaster wall, it is desirable that the exterior of the cabinet be flush with the wall surface. It is also desirable that the door or doors and apron of the cabinet be so arranged that the doors may be swung open without disturbing the apron, to afford unimpeded access to the interior of the cabinet for inspection, removal or replacement of any of the elements contained therein.
it is an object of the invention to provide a switch, compact in structure and simple in operation, which is adapted for use in circuits carrying relatively heavy currents, as for electric power units. It is a further object of the invention to provide a switch box or cabinet containing one or more fused switches, the cabinet structure be ing such that the fuses are necessarily disconnected from all sources of electrical energy when exposed for handling, and the live parts of the switch or switches are emciently shielded from manual contact by means of a barrier member whichis removable to permit access to the live parts iorinstallation or inspection purposes. The box or cabinet structure is also such that the fuses are accessible for inspection or replacement when the box is open, and the door or doors, when shut, close the cabinet tightly so as to prevent egress of flame when an electric arc occurs in the cabinet, as, for example, when a fuse blows therein.
According to the invention, a switch box or cabinet is provided which may have one or more switch units therein, such as a main switch, a power switch, and fused connections for lighting circuits. in the cabinet the live parts and the wiring associated therewith are shielded by a dead-front partition from being accidentally touched. This partition is preferably removable to permit inspection of the switch members and wiring contained in the rear compartments of the box. The cover of the box is preferably in the form of one or more separate sections or doors which can be independently opened, each door or cover section corresponding to one of the switches in the box or to the fused connections for the lighting circuits. One or more of the doors may carry switch elements adapted to cooperate with corresponding elements mounted in the box, and also fuses associated with such switch elements. Each door is preferably provided with flanges which effect a tight closure of the corresponding portion of the cabinet before the closing movementof the door connects the fuse carried thereby into the circuit.
For a more complete understanding of the invention, reference may be had to the description thereof which follows and to the drawings of which-- Figure 1 is a front elevation of an embodiment of the invention showing part of the box cover closed and part open.
Figure 2 is a perspective view of a dead-front partition member adapted to be secured in the box.
Figure 3' is a section on the line 3-3 of Figure 2.
Figure 4 is a perspective rear view of the box showing a flush apron attached thereto.
Figure 5 is a section on the line Ir-5 of Figure 1.
Figure 6 is a section on the line 6-45 of Figure 5.
Figure 7 is a wiring diagram of the electrical apparatus contained in the box.
Figure 8 is a perspective view of a box having a different arrangement of the units.
In the embodiment of the invention illustrated in Figures 1 to '7, the invention comprises a sheet metal switch-box or cabinet iii adapted to besecured in an uprightpcsition against a wall or partition of a building, or to be sunk in a wall flush with the surface thereof. Secured to the rear wall of the box iii is a block E2 of insulating material on which are mounted switch teranimals it of any desired or suitable form, these switch terminals being preferably of a form adapted to cooperate with switch blades so as to close the circuit. The blocks it are secured to the rear wall of the box ill, preferably by means of screws passing through holes in the rear wall of the box. This permits adjustments of the contacts when the cover is closed. The block 82 of insulation is preferably provided with a ridge portion l8 which projects further forward than the terminal elements M so that it constitutes a spacing element of insulating material separating terminal elements of opposite polarity.
As indicated in Figure 7, the box l0 may be provided with two switch blocks 12, one of which is mounted in the upper portion of the box, the other being mounted in the lower portion of the box. Between these two switch blocks may be mounted a base member 20 of insulation on which are a number of plug-fuse sockets 22, four such sockets being illustrated. As shown, .the line wires 24 may enter the box and be connected to certain of the switch terminals H, and conductors 26 may lead from the other terminals 14 of the upper switch to a pair of terminals of the lower switch. Load wires 28 may be connected to the other terminals of the lower switch, wires 28 preferably leading to a range or some other electric unit requiring a relatively heavy current. Connections to the fuse-receiving sockets 22 may be tapped off from the conductors 26 in a manner well known in the art, the fuses in the sockets 22 being employed to control lighting circuits connected therewith.
In order to shield the live members in the box from accidental contact by the fingers of a person operating any of the switches, a dead-front partition member 30 may be provided, such memher being illustrated in Figure 2. As therein shown, this member may consist of a sheet of metal having a bottom portion 32 and side walls 34 bent up therefrom. Extending from one side wall to the other are a pair of partition members 36 which divide the space between the side walls 34 into three compartments corresponding respectively with the upper switch, the central fuse block for the lighting circuits, and the lower switch. As the sheet metal of which the partition members 35 are made is preferably similar to or lighter than the stock usedfor the walls of the cabinet, the effective width of the forward edges of the partition members is preferably increased as by bending back a portion 31, for purposes hereinafter set forth. The bottom portion 32 of the dead-front member is provided with large apertures in the upper and lower compartments, sheets of insulating material in being secured over such apertures to close the same. As illustrated in Figure 3, a pair of insulation sheets may be provided for each aperture, these sheets being held together by rivets 42 or any other suitable means. The insulating sheets 40 are providedwith narrow slots ll located over respective terminals I4 and adapted to receive switch blades as hereinafter described. The middle portion of the bottom 32 of the dead-front member is preferably provided with an aperture 48, which, as shown, may be in clover-leaf form to expose the four sockets 22 so that fuse plugs may be inserted therein or removed therefrom without disturbing the dead-front member. As indicated in Figure 5, the rear wall 32 of the dead-front member may abut the portions l6 of the switch block l2. If desired, a transverse partition 50 may be mounted in the box to extend from the rear wall thereof to the dead-front member, thus dividing the space behind the dead-front member into two separate compartments.
The box I0 is preferably provided with custornary knock-outs 52 formed in the side and rear walls thereof to facilitate the entry of wires through the rear of the box or through any of its sides. All of these knock-outs are rearward of the dead-front member 30, so that this member shields not only all of the terminal elements mounted in the box, but also all of the wiring within the box. The dead-front member may be removably held in place by any convenient means. As shown, the side walls 34 each have a central aperture 54 to receive a machine screw 56 which projects through the opening and is screw-threaded into the side wall of the box in. The rear wall or bottom portion 32 of the deadrront member is approximately of the same length and width as the interior of the box so that its side and end edges abut the side and end Walls of the box, completely shielding the apparatus in the box behind the dead-front member. The side walls 34 of the dead-front member preferably fit snugly against the side walls of the box so that their engagement with the walls of the box, together with the abutting engagement of the rear wall 32 of the dead-front member with the insulating blocks i2, provides a firm seating for the dead-front member in the box. By removing the screws 56, however, the dead-front member can readily be taken out, thus exposing all of the electrical apparatus in the box.
The cover of the box is preferably made in a plurality of separate sections, each section corresponding to a portion of. the apparatus behind the dead-front member. As shown in Figure 1, the cover of the box consists of three sections or doors B0, B2 and 64, these doors registering respectively with three compartments formed by the partition elements 36. On the inner faces of the doors 60 and 54 are mounted insulating blocks I0 which carry switch blades 12, and, if
desired, fuse holders 74. These blocks are secured to the doors, preferably by means of screws 15 passing through holes in the doors. As shown, the fuse holders are adapted to receive cartridge fuses 16 in a manner well known in the art. The switch blades 12 are adapted to project through corresponding slots 44 when the doors are swung shut, the ends of the blades coming into contact with the respective terminals l4 behind the deadfront member. In order to protect the user from possible contact with a charged part, the doors and 84, which carry switch blades T2, are provided with flanges 80 adapted to telescope inside the walls of the respective compartments closed by these doors. The flanges 80 are preferably turned downwardly from a plate 81. The plate 8| is preferably positioned on the cover by screws 15 passing through holes in the cover and plate. The width of the flanges 80 is sufllcient to cut oil access to the interior of the forward compartments of the box before theswitch blades 12 come into contact with their respective terminals ll, so that, when the switch blades T2 are electrically charged, they are not accessible and cannot be touched by the fingers of the user. The door 82 is also provided with a flange 8| which need not be made as wide as the flange 80. The
flanges 80 and 8! are offset from the four side edgesof their respective doors so as to give the doors an emoiently rabbeted structure cooperating with the walls and partitions of the box, when the doors are closed, to form a closure such that the crack or, clearance between the marginal portion of each door and the adjacent box walls will have an angle therein. That is, when a door is closed, at no point can a straight object like a pin be thrust through the crack between the door and box walls. To this end, in-
order to receive the marginal portions of the doors, the partition members 35 are widened at their forward edges, as hereinbefore described,
this being done by any suitable means as, for example, a bent-back portion 31.
It is also desirable that the flanges 80 and BI engage the adjacent box walls and partition members frictionally so as to hold the doors against being accidentally or too easily opened. While it may not be practical in actual manufacture to fit the flanges 80 and BI into the compartments so accurately that they will have continuous engagement with the walls and partitions when shut, the flanges can be fitted for frictional contact with the walls and partitions at several points. Such engagement is facilitated by the bent back portions 31 of the partition members 36 which permit slight resilient yielding when engaged by the flanges of the doors.
For compactness of structure, the doors 60, 62 and 641 may conveniently be hinged to the box ill by a piano-type of hinge consisting of alternate elements integral with the side wallof the box, the other elements being integral with the doors of the box. Each of these elements preferably consists of a tongue projecting from an edge of the side wall of the box or one of the doors of the box and curled as indicated in Figure 6 to receive a hinge pin. The tongues or elements are spaced, the spaces having the same width as the tongues so that the elements of the side wall of the box fit into the spaces between the elements on the box doors, and vice versa. A single hinge pin 82 may project through all of these elements. This results in a hinge structure which projects but slightly beyond the planes of the outer faces of the adjacent side wall and doors of the box. With hinges as shoum, cabinets may be mounted side by side practically in contact, but the doors may be swung wide open without interference with adjacent cabinets. If a cabinet is mounted in a wall so as to be sub stantially flush with the face thereof, the hinge structure projects out slightly from the plane of the wall and doors. but such projection is hardly observable. By providing a piano-type hinge having tongues integral with the door in which holes for the screws 15 are located and having alternate tongues integral with the box ill in which the screws i are located, exact alignment of the switch members secured by those screws is made possible. Furthermore, the flanges 8'1 are accurately aligned by reason of the fact that they are positioned on the cover by screws I5 passing through holes in the plate Bl. For flush mounting in a wall, a suitable apron 84 may be provided. this apron being secured to the box flush with the doors-thereof by'any suitable means such as a series of bracket elements 86, which, as shown, may be attached by bolts to the bottom of the box and to the apron.
The apron may be in the form of a hollow rectangle which fits snugly around the front contour of the box, including the hinge. The bracket members 86 are preferably of such a length that the apron is held in the same plane as the doors when the latter are shut. As thus arranged. the doors may be swung wide open to permit the removal of any of the contents of the box, including the dead-front partition member 30, without disturbing the apron or the box itself.
The several doors 6!], 62 and 64 may each be provided with a suitable bail or handle 88 whereby they may be readily swung open. If desired, suitable lugs 90 may be provided with one or more of the doors so that they may be sealed shut as indicated at 92 in Figures 1 and.6. The sealing lugs 90 are preferably pivotally mounted on the front partition member box wall so that they can be swung clear of the plane of the doors so as not to" interfere with the apron when an apron is mounted on the box as described.
The invention is illustrated as embodied in a cabinet having three units; It may also be embodied in cabinets having one, two or more units. Instead of having three units in the box arranged in vertical array as illustrated in Figure 1, various other arrangements are possibleas, for example, that illustrated in Figure 8. As therein shown, the portions of the box containing the main and heater switches are arranged side by side, the portion of the box containing the fuse sockets for the lighting circuits being below the other sections. It is evident that other convenient arrangements are possible.
The invention herein shown and described is capable of various modifications and changes without departing from the spirit or scope thereof as defined in the following claims.
1. Apparatus of the class described, comprising a fused switch box consisting of a back wall,
side walls and end walls, said side and end walls having knockouts therein, insulated switch terminals mounted in said box, a dead-front partition member removably mounted in said box, said partition member being spaced from the back wall of the box and abutting all the side and end Walls thereof to mask all said switch terminals and associated wiring, a cover hinged to said box, switch elements carried by said cover and movable therewith into engagement with said switch terminals when the cover is closed, and fuse-holding elements mounted on said cover and electrically connectedwith respective switch elements, said partition member having a portion of insulating material with openings therethrough for said switch elements.
2. Apparatus of the class described, comprising a switch box consisting of a back wall, side walls and end walls, said side and end walls having knockouts therein, a. dead-front partition member removably secured in said box and abutting all the side and end walls thereof, switch terminals mounted in said box between the back wall thereof and said dead-front member, a cover member hinged to said box, switch structure including contact blades mounted on said cover and movable therewith to cause said blades to engage said terminals, said dead-front member having narrow slots therethrough to receive said blades when the cover is swung, shut, and a flange projecting from the inner face ofsaid cover member and of sufllcient width to telescope within the box walls so as to cut off access to said switch structure before said blades move into contact with said terminals.
3. Apparatus of the class described. comprising a metal switch box, a plurality of insulation b ocks secured to the rear wall of said box. switch terminals mounted on said'blocks, each said block having a portion extending further forward than any of the terminals mounted thereon, a deadremovably secured against said blocks and extending to the side and end walls of the box, said dead-front member having a portion of insulating material slotted to receive contact blades for engagement with said terminals, and a plurality of cover members hinged to said box, each said cover member having thereon switch structure including contact blades adapted to engage the terminals carried by one of said insulation blocks.
4. Apparatus oi the class described, comprising a switch box, a plurality of switch blocks mounted on the rear wall or said box, switch terminals mounted on said blocks, a dead-front member removably secured in said box in front of said blocks, said member consisting of a metal sheet having approximately the same length and width as the interior of the box, side walls extending forward from said sheet and lying against the side walls 01' the box and transverse partition elements extending from one side wall 01' said member to the other to form therewith. a series of compartments, said metal sheet having substantial apertures therethrough registering with said switch blocks, plates of insulating material secured over said apertures and provided with narrow slots, a cover on said box, and switch elements carried by said cover and adapted to project through said slots when said cover is,
member dividing the space in,the box formed.
in the dead-front member into three compartments corresponding respectively to the live terminals, the load terminals and the lighting circuit connections, three cover elements hinged to the box and independently swingable to open and closed positions, each said cover element registering withone of said compartments, and fuseholding switch structure mounted on two ofsaid cover elements and including blades movable through said slots into contact with respective line and load terminals.
6. Apparatus of the class described, comprising a switch box having knock-outs in the walls thereof, a set of line switch terminals and a set of load switch terminals mounted within said box, a dead-front partition member rerriovably secured, in, said box and forming therein Rent and rear compartments, said partition member abutting all the side -and end walls of the box forward-o! the knock-outs whereby all wiring entering the box is behind said partition member, a pair or separately operable cover members hinged to said box, each said cover member carrying switch structure including fuse-holding elements and contact blades adapted to move into contact with a corresponding set or said switch terminals, said partition member having narrow slots therethroush to receive said blades, and forwardly-proiecting partition means on said partition member subdividing said forward compartment so that, when either of said cover thereby is entirely enclosed.
V. Apparatus of the class described, comprising-a switch box having knock-outs in the sides thereoi, insulation members mounted in the box, switch terminals mounted on said members, a dead-front partition member removabiy secured in said box, said partition member being spaced from the back wall of the box and abutting all the side and end walls thereof to mask all said switch terminals and associated wiring, a cover hinged to said box, switch structure including fuse-holding elements and contact blades mounted on said cover, said blades being arranged to move into contact with said terminals when the cover is closed, said partition member having narrow slots for the projection of said blades therethrough, and a flange on the periphery of said cover adapted to telescope within the box as the cover closes so as to cut off access to the said blades before they move into contact with said terminals.
8. Apparatus oi the class described, comprising a sheet metal switch box, a cover member hinged to said box, switch elements mounted within said box, cooperating switch elements mounted on said cover member, a sheet metal flange on said cover member spaced inwardly from the edge thereof and arranged to telescope within the walls of said box with yielding frictional engagement when the cover is closed and of sufficient width to cut oil access to said switch elements before the switch is closed.
9. Apparatus of the class described, comprising a switch box, a cover member hinged to said box, switch elements mounted in said box, cooperating switch elements mounted on said cover, a dead-frontpartition member shielding the ele ments mounted in said box and provided with apertures to receive the elements mounted on said cover when the cover member is closed, and a flange on the'cover member telescoping within the walls of the box when the cover is closed and oi! suflicient width to cut of! access to said switch elements before the switch is closed.
10. A sheet metal box having a cover therefor hinged to the corresponding side wall of the box,
a set of binge members formed directly from the said side wall, a second set or hinge members formed directly from said cover, said hinge members being disposed in alternate and abutting relationship on a hinge pin, a plate secured to the cover, said plate having flanges thereon extending inwardly so as to telescope within the box when the cover is closed, a fixed switch member mounted on the rear wall of the box, a second switch member mounted on the cover and movable therewith into engagement with the first switch member, said flanges being of sufficient width to cut oil access to said switch elements before the switch is closed, mounting means for said switch members and said plate including holes ln'the rear wall and the cover, said holes being spaced with relation to said hinge members to insure substantially accurate engagement between the switch members and between the flanges and the inner walls of the box when the cover is in closed position.
ERNEST G. JOHANSSON.