US2197054A

US2197054A - Service control equipment

Info

Publication number: US2197054A
Application number: US212152A
Authority: US
Inventors: Ralph A Millermaster; Alex A Writzmann
Original assignee: Cutler Hammer Inc
Current assignee: Cutler Hammer Inc
Priority date: 1938-06-06
Filing date: 1938-06-06
Publication date: 1940-04-16
Anticipated expiration: 1957-04-16

Description

Allril 16, 1940. R. A. MILLERMASTER ET Al. 2,197,054

SERVICE' CONTROL EQUIPMENT Filed June 6, 1938 4 Sheets-Sheet 1 m w ...wam m N J d w .lo M ,l0 n@ M a@ V. .b l aM .n 9 .b l .1 W w, m m ..9 l .W wrn l 1 .7 alu l rh A @@Jw, 1%@ n u m mu M1 mi. ,uw @wm c J W noS -L m.. l a m L? .m .www u c Q, @g a NW 'ma Si uw l 7 .A u :La u o w Apnl 1e, 1940.

R. A. MILLERMASTER Er AL 2,197,054

SERVICE CONTROL EQUIPMENT Filed June 6, 1938 4 Sheets-Sheet 2 APT 16, 1940. R. A. MILLERMASTER r AL 2,197,054

SERVICE CONTROL EQUIPMENT Filed June 6, y19258 4 Sheets-Sheet 3 April 16, 1940. n. A. MILLERMASTER Er A1. 2,197,054

SERVICE CONTROL EQUIPMENT Filed June 6, 1938 4 Sheets-Sheet 4 vz 1474 74 14" ao Patented Apr. 16, 1940 2,191,054 4 sanvica coN'raor. momma* Ralph A. Millermaster and Alex A. Wrltlmann,

Milwaukee, Wis., assignors to Cutler-Hammer,

Inc., Milwaukee, Wis., a; corporation of Dela- Application June 6, 1938, -lSerial No. 212,152 1s clama (ci. co-114) 'Ihis invention relates to improvements in service control equipment.

A primary object of the invention is to provide a novel form of service switch device including a i'useless main switch, in combination with range and branch circuit fuses.

Another object is to provide service control equipment wherein the necessity for use of main fuses is eliminated.

Another object is to provide a service switch and fusing device oi the aforementioned'character of extremely compact and inexpensive construction.

Another object is to provide a novel form of il range fuse pull-out as a part of the combination.

Another and more specific object is to provide for positioning of the range fuses in end to end relationship to each other transversely of the casing which houses the complete device.

Another object is to provide for positioning of a plurality of branch circuit fuses in a single row at one side of the range fuses.

Another object is to provide such a device wherein the main switch is positioned at the u opposite side of the range fuses from that last mentioned.

Another object is to provide a novel form of enclosing casing including a main cover member having a relatively small opening to provide clearance for and accessibility of the pivoted operating lever of the main switch at the front face of the casing, together with a relatively large opening to provide access to the range and branch circuit fuses.

Another object is to provideguard means carried by and cooperating with said main cover member to prevent access to the wiring terminal elements of the device.

Another object is to provide an auxiliary cover member hinged to said main cover member and having novel means to yieldably restrain the same in a position to close said relatively large opening or in a position to provide access through the latter to said range and branch circuit fuses.

Another object is to provide novel means on said main and auxiliary cover members to provide for sealing of the latter to the former.

Another object is to provide a range fuse pullout plug having an operating handle of novel o f01'm.

Another object is to provide a combination device oi the aforementioned character which may be installed in either normal or inverted position, with assurance that the auxiliary cover member u will stay open or closed as desired, and wherein l molded insulating base showing parts the on" and oiT indication of the main switch reads correctly in either position of the casing.

Another object is to provide a device of the aforementioned character with means to en-v able testing of any of the various fuses while in 5 position.

Other 'objects and advantages of will hereinafter appear.

The accompanying drawings illustrate a preferred embodiment of the invention which will now be described, it being understood that the embodiment illustrated is susceptible of modification in respect of certain structural details thereof without departing from the spirit and scope of our invention as defined by the appended claims.

In the drawings,

Figure l is a top plan view of a service control device having the parts thereof constructed and arranged in accordance with our invention,-the main and auxiliary cover members being removed.

Flg. 2 is a bottom plan view of the one-piece of the switch mechanism and the bus connections between the several parts of the complete device.

Fig. 3 is a bottom plan view of oui` novel form of range fuse pull-out plug, whereby the range fuses may be mounted in tandem, or end to end, relation. 30

' Fig. 4 is a side elevation of the plug shown in Fig. 3,-with parts broken away and in section to illustrate the manner of attaching the various metal parts to the insulating base of the plug.

Fig. 5 is a fragmentary sectional view, on the line 5 5 oi Fig. 1,-the main and auxiliary cover members being shown in assembled relation.

Fig. 6 is a fragmentary sectional view, on the line 6-6 of Fig. 5, showing the parts of the fuseless main switch in circuit interrupting position.

Fig. 7 is a view substantially like that of Fig. 6,-but showing the switch parts in circuit completing positon.

Fig. 8 is a detail perspective view (substantially full size) of a stationary part of our improved form of solderless wiring terminal.

Fig. 9 is a bottom plan view (double scale) of the clamping nut for cooperation with the part shown in Fig. 8. 50

Fig. 10 is a sectional view, on the broken line |0-i0 of Fig. 2.

Fig. 11 is a detail relation, of certain parts oi one of contacts of the switch.

the invention perspective view, in separated the resilient Fig. 12 is a diagram showing the circuit connections for the various parts of the complete device.

Fig. 13 is a fragmentary sectional view of a portion of the main cover member and a portion of the auxiliary cover member,showing the form and arrangement of one of the integral finger lugs formed on the. free end oi' the latter, and

Fig. 14 is a fragmentary sectional view, similar to Fig. 7,-but illustrating a slightly modified form of insulating base to provide therein a downwardly opening bearing slot to receive the pivot pin of the operating lever.

Referring to the drawings, the numeral i designates a single molded insulating base adapted to be produced by a straight-line molding operation from a Suitable material, such as gray porcelain. Base l5 as shown is of approximately rectangular contour,except that the corners have been omitted at I8 and l1 to avoid an unnecessary weight or mass of material. Extending transversely of base i5 intermediate the ends thereof (Fig. 1) is a relatively long, outwardly opening, substantially rectangular recess I8,

which is adapted to accommodate in a substan-l tially flush relation a correspondingly shaped pull-out plug the molded insulating base of which is designated by the numeral i9. Base I9 is provided with parts, hereinafter described, to receive and retain a pair of cartridge type range fuses in tandem, or end to end, relationship to each other.

Arranged in a line at one side of recess i8, and in a plane offset downwardly from the outer end of the latter (see Fig. 1), is a series of four substantially cylindrical recesses 28, 2|, 22 and 23, each of which is respectively adapted to accommodate a screw shell contact 24 and a center contact 25 for cooperation with the screw shell and center contacts of branch circuit fuses of well known form.

Arranged at the other side of recess I8, and in a plane offset downwardly slightly below the plane of the upper ends of recesses 20 to 23 (see Fig. 10) is a main switch mechanism,-the insulating operating lever 54 of which projects upwardly a substantial distance beyond the upper end of recess IS. Base i 5 is housed within a casing, preferably formed of sheet metal, comprising side walls 21 and 28,

end walls

29 and 30, and a bottom wall 3l,-to which base l5 is rigidly secured, as by means of a pair of relatively short screws 32, and a pair of relatively long screws, one of which is shown at 33 in Fig. l. Said pairs of screws 32 and 33 are preferably arranged in the form of a rectangle, as best illustrated in Fig. 2 by the pairs of

openings

32a and 33a adapted to accommodate the same.

The open front of said casing is provided with a main cover member 34, formed of stamped sheet metaL-said. cover member having a peripheral flange which exteriorly overlaps the upper ends of the aforementioned side and end walls, as shown at 35 in Fig. 5. Main cover member 34 is secured to the casing as by means of four screws, one of which is shown at 36 in Fig. 5, which penetrate openings provided at the respective corners of said cover member and take into tapped openings 31 provided in the horizontal arms 38 of brackets, the vertical arms 39 (Fig. 5) of which are welded or otherwise rigidly secured to the opposite ends of side walls 21 and 28.

Main cover member 34 is provided with a relatively large rectangular opening 40 (Fig. 5) which is adapted to provide free access to the recess I8 and to the relatively small cylindrical recesses 2U to 23, inclusive. Surrounding opening 40 is a ange 4Iwhichisoiisetinwardlyfromtheouter' Surface ot said main cover member,-said Hanse being adapted to accommodate the auxiliary cover member 42 in a relation substantially iiush with said outer surface of said main cover member. Auxiliary cover member 42 is attached to the main cover member as by means o! a pair oi' hinge members of well known form-one of which is shown at 43 in Fig. 5. Auxiliary cover member 42 is provided near its upper end with an opening 44 to accommodate the perforated upstanding lug 45 formed integrally with the aforementioned danse 4| The perforation 48 in said lug is adapted to receive the loop portion of a wire whose ends may be sealed together in the usual manner, to provide for sealing of said auxiliary cover member to said main cover member.

Secured to the inner surface of auxiliary cover member 42 (Fig. 5) at the hinged end of the latter, as by means of a rivet 41, is a resilient plate or spring 48; the fixed end of which is provided with a circular opening to accommodate with a kclose t the cylindrical boss or extrusion 49,

formed on said auxiliary cover member, whereby turning of plate 48 relatively to rivet 41 is prevented. 'Ihe free end of plate 48 underlies the adjacent portion of the aforementioned flange 4l and cooperatively engages the inner edge of the latter to yieldably retain the auxiliary cover member 42 in the closed position thereof illustrated. Assuming vertical mounting of the complete device in the manner illustrated in Fig. 5, it is to be understood that plate 48 will cooperate with the edge of flange 4I to yieldably resist a portion of the opening movement of auxiliary cover member 42, whereupon the latter will tend to move by gravity to a fully opened position substantially 180 degrees removed from the closed position illustrated.

On the other hand, if the complete device of Fig. 5 is mounted in a vertical position reversed, or upside down, with respect to the position illustrated, plate 48 will cooperate with ilange 4l to resist a portion of the opening movement of said auxiliary cover member, and thereafter plate 48 will cooperate with the inner edge of flange 4l to hold said auxiliary cover member in a horizontal position affording i'ree access to the aforementioned recesses i8 and 20 to 23. To facilitate opening of the auxiliary cover member 42 we prefer to provide the same, at the end thereof opposite to the hinges, with a pair of integral lugs bent outwardly to arcuate form in cross secticn,- one of said lugs being shown in elevation at 50 in Fig. 5, and in section in Fig. 13. Also as shown in Fig. 13 the main cover member 34 is provided with non-oil'set portions 5i of arcuate form which underlie portions of the lugs 58 to minimize the apparent degree of projection of the latter when viewed from the front. A commercial form of our combined main and auxiliary cover members is illustrated in our Design Patent No. 108,212, dated Feb. 1, 1938.

As shown in Figs. 5 to 7 the main cover member 34 is provided with a narrow, elongated depression or offset 52 having formed therein a slot 53 which acts to guide and limit oscillatory movement of the operating lever 54 of the main switch. Underlying the slot 53 is a flat sheet metal plate 55 having an opening formed therein to accommodate lever 54,-a pair of

lugs

56 and 51 being formed integrally with and upstanding from opposite parallel sides of said openlng,-the upper ends of said lugs being bent laterally over the bottom wall of depression 52, as shown in Fig. 5,

whereby plate 55 is supported by but slidable with respect to said main cover member 34. As shown in Figs. 6 and '1, plate 56 acts to substantially close the aforementioned opening 63 in all positions of the lever 54. Cover member 34 is provided adjacent to the right-hand end of depression 52 with the legend 05" and at the lefthand end thereof with the legend On, to indicate the "off and on positions of the main switch (Figs. 6 and '7).

The main switch comprises a relatively narrow substantially rectangular cavity 58 which opens to the lower surface of base I5,a passage 59 communicating with recess 58 and opening to the upper surface'of said base. In assembling the switch mechanism lever 54 is inserted upwardly through passage 59 to an extent sufficient to permit insertion of pin 66 through the pivot opening 6I provided in said levensaid lever being then lowered to effect seating of pin 66 in the open pivotal bearings 62 and 63 (Fig. 5) provided in the upper surface of vbase I5. A metal plate 64 overlies the opposite ends of pin 68 to restrain the latter from upward displacement relatively to

bearings

62, 63; plate 64 having an opening 65 formed therein to provide clearance for lever 54. Plate 64 is secured to base I5 as by means of a pair of bolts 66 the heads of which are located in countersinks provided in the end wall of recess 58 (Figs. 6 and '7) Lever 54 preferably consists of a flat punched plate of fiber impregnated with a suitable insulating binder material. Any other suitable tough and relatively rigid, fiber reinforced, insulating material may be employed if desired. As best illustrated in Figs. 6 and 7, the lower end portion 54EL of lever 54 extends from the point of pivotal support at an obtuse angle to the upper end portion of said lever,the arrangement being such that in the off" position of the switch parts (Fig. 6) said lower end portion 54* of the lever is in a substantially vertical position with respect to pivot pin 66.

The lower end portion 54 of said lever is pivotally attached to a substantially rectangular insulating plate 61, at one side of the horizontal and vertical center lines through the latter, as by means of a hollow rivet or eyelet 68. The lower edge of plate 61 is notched or cut away, as indicated at 69, to provide clearance between the same and an insulating barrier plate 10, which is interposed between the sets of cooperating stationary and movable contacts of the switch. As shown in Figs. 6 and 7 the plate 61 is of substantially inverted U-shape,with the arms thereof projecting to a slight extent below recess 58 in the on position of the switch (Fig. '1), while the same project to a greater extent below said recess in the off position of the switch (Fig. 6).

Secured to the lower surface o f base I5 (Fig. 2) area pair of substantially rigid stationary contacts 1I and 12 of like form,the free ends of which underlie, to a very slight extent, the recess 58 (see Fig. 10) Secured to the lower surface of base I5 at the opposite side of recess 58,-and adapted to underlie the latter and portions of contacts 1I and 12, is a pair of resilient contacts 13 and 14 of like form. Contacts 13 and 14 preferably consist of laminations or superimposed strips of resilient conducting material, such as phosphor bronze,the inner laminations of the respective contacts 13 and 14 having hollow bosses or projections 13, 14* formed thereon (see 14al in Fig. 10), which bosses are normally biased into engagement with the respective contacts 1I, 12. In Fig. 11 we have shown in perspective the inner lamination 14b having said boss 14 formed thereon, together with one of the three other laminations 'I4c which we prefer'to employ. The initial upward angle provided for the free ends of the laminations like 14 affords the normal bias of the boss (like 14) into engagement with its cooperating stationary contact.

Contacts 13 and 14 are clamped in position against the

respective bus members

15 and 16 as by means of bolts 11, 18 and

nuts

19, 80,-the heads of said bolts being located in countersinks provided in the upper surface of base I5 (see bolt 18 in Fig. l0), Associated with bus member 15 is a bolt 8| (Fig. 2) the shank of which extends upwardly through base I5 and takes into a tapped opening provided in the bottom wall of a channelshaped wiring terminal element 82 (Fig. 1) to clamp the latter in position. The exposed surface of said bottom wall is provided with a series of alternate grooves and ridges which extend in parallel relation between the side walls of said channel-shaped element, as shown in detail at 82a in Fig. 8.

The threaded shank of bolt 8I preferably extends a substantial distance above the side walls of the channel-shaped element 82 for cooperative engagement by a wire-clamping nut of novel form. As shown, in Fig. 9 said nut comprises a lower cylindrical portion 83, the flat lower end of which is provided with a series of concentrically arranged alternate grooves and ridges 83. By reason of the formation of

elements

82 and 83 as described we are able to properly clamp a stranded conductor of a size which could not ordinarily be accommodated by known forms of solderless wiring terminals of similar size. A bolt 16a (Figs. 1 and 2) associated with bus member 16 likewise takes into a tapped opening in the bottom wall of its associated channelshaped terminal member 82 to clamp the latter in position.

In practice the strands of the wire will be divided, for positioning thereof on opposite sides of the bolt,-whereupon the cylindrical portion B3 of the nut will be screwed home, the slight degree of clearance betwe-en portion 83 and the side walls of element 82 being insufficient to permit escape'of any of the wire strands, and the surfaces Il!a and 83a cooperating with the wire strands to insure a proper and efficient electrical engagement. As shown in Figs. 5, 9 and 10 said nut is provided with an upper end portion 63h of hexagonal or other polygonal contour, to provide for tightening or loosening thereof by means of a suitable wrench,-it being noted (Figs. 5 and l0) that the upper end or head portion 83b of the nut will always clear the side walls of element 82. Also as shown in Figs. 1 and 10, head portion 83b is provided with a kerf 83c to enable adjustment of the nut by means of a screw driver. The screw driver to be employed will preferably have a forked blade, to provide clearancel for the shank of a bolt, such as 8| in Fig. 1. We have disclosed use herein of seven solderless wiring terminal units of the character just described, as indicated by the like reference characters applied thereto.

Referring again to Figs. 6 and 7, it .will be noted that in the off position of the switch the plate 61 abuts at one edge against the left-hand vertical end wall 58H of recess 58 to insure substantially identical spacing of contacts 13 and 14 from the respective stationary contacts 12. Upon a slight degree of counterclockwise movement of lever 54 the resilient contacts 13 and 14 act upon the arms of plate 61 to bias the same upwardly and laterally with a quick action, toward the extreme position thereof shown in Fig. 7, with consequent normal and automatic acceleration of the counterclockwise movement of lever 54.

Referring to Figs. 1 and 10, recess I8 is provided in its bottom wall I8x1 along one longitudinal side thereof with four constricted openings-one pair of which is shown at I8b and I8 in Fig. 1,-and one opening of the other pair is shown at I 8d in Fig. 10. Located within suitable recesses (such as recess 84 in Fig. 10) beneath the respective openings are jack receiving contacts of the form illustrated in cross section at 85 in Fig. 10. Each of said contacts preferably consists of a resilient strip of metal, such as phosphor bronze, bent to provide a pair of spaced, upwardly extending parallel arms with outwardly flared ends, and a reflexed connection portion bent laterally to underlie a portion of base I5.

As shown in Fig. 10 the connecting portion of one of said contacts is interposed between the terminal end of stationary contact 12 and base |5,-a bolt 86 having its head located in a countersink in the bottom wall of recess i8 and its threaded shank freely penetrating openings provided in the connecting portion of contact 85 and in the terminal portion of contact 12 and taking into a tapped opening in bus member 8'I toclamp said parts in assembled relation. The three other jack receiving contacts, like 85, are secured in position by

bolts

88, 89 and 90 (Figs. 1 and 2). Bolt 88 takes into a tapped opening in bus member 9|; bolt 89 takes into a tapped opening in bus member 92; and bolt 90 takes into a tapped opening in bus member 93 (Fig. 2).

n As shown, bus member 92 overlies the terminal end of contact 1I to latter in position.

The other end of bus member 9| is engaged by the head of bolt 94, the shank of which takes into a tapped opening in the bottom wall of one' of the channel-shaped wiring terminal members 82 (Fig. l). Similarly, the other end of bus member 93 is engaged by the head of bolt 95, the shank of which takes into a tapped opening in the bottom wall of another of the channelshaped wiring terminal members.

The cartridge type fuse carrying plug comprises the aforementioned insulating base portion I9 having four relatively shallow, substantially rectangular recesses |911, |91, |9111 and |911 formed in the inner surface thereof. Each of said recesses is provided substantially centrally thereof with a metal insert in the form of a bolt having a roughened inner end portion 96" embedded in base I9 for non-rotatable anchorage thereof,-the exposed threaded shank 9611 of each bolt being adapted to penetrate alined openings provided in the base portions 91a, 981 of the jack blade members 91 and the fuse clips 98, respectively. Nuts 99 cooperate with shanks 9Gb to clamp

members

91 and 98 in assembled position against the bottom Wall of a recess (such as |911) and against the integral annular extension 96c formed on each bolla-spring lock washers |00 (Fig. 4) of suitable form being employed to prevent accidental turning or loosening of said nuts.

'As shown, the jacks 91 are arranged adjacent to one longitudinal side of base I9 whereby the same are adapted to register with the aforemenprovide for clamping the tioned constricted openings |85, |8, etc., in the bottom wall I8* of recess I8 in only one relative position of the parts.

Base |9 is preferably provided at its mid-length on opposite sides thereof with slight lateral projections I9l and |911, and the opposite longitudinal walls of recess I8 are formed as shown at I8e and |81 (Fig. 1) to accommodate said projectionsit being noted that the lower ends (Fig. 4) of projections |91, I9b are of irregular angular contour, as indicated at |9C, I9, and the lateral recesses I8=, I8t are correspondingly shaped to insure against insertion of plug I9 into recess I8 in more than one relative position of said parts.

Base I9 is also preferably provided, at a point offset from the mid-length thereof, with an integral barrier member |98, which extends downwardly throughout the major portion of the length of jacks 91. The opposite edges |911, |91 of said barrier-member extend laterally beyond the projections |91, |911 throughout a portion of the lower ends of the latten-recess I8 being provided in its longitudinal walls with recesses I 8', |811 (Fig. 1) to accommodate said extensions, to additionally limit plug base I9 to insertion in recess I8 in only one relation of said parts. The two longitudinally alined pairs of clips 98 are adapted to receive and retain a pair o1' cartridge type fuses for range service.

As shown in Figs. 1 and 10, recess I8 is provided with a barrier |0I formed integrally with the side and bottom walls thereof and extending upwardly from the latter to the degree indicated in Fig. l0, and to provide a seat for the ledge or surface I9J formed on base I9 (Figs. 3 and 4). By reason of the overlapping relationship of barriers 0| and |92, the recess I8 is divided into two compartments effectively sealed electrically with respect to each other prior to engagement of the jack blades 91 with contacts 85. The depth of the peripheral wall of plug base |9 is also preferably such that the upper end of recess I8 is completely sealed off thereby, 0r made dead-front prior to engagement of jack blades 91 with contacts 85.

Plug base I9 is provided with a pair of spaced openings to accommodate the shanks |02n of a pair of cotter pins whose loops or eyes |02 are exposed at the outer surface of said base, said Shanks having their ends spread or bent over washers |03 to retain said cotter pins in position. The handle comprises a length of relatively heavy resilient wire |04, preferably steel, bent to substantially U-shape with laterally extending ends |041, |04", either of which may be freely inserted into one of the eyes |02, whereupon the other end of said handle may be forcibly inserted into the other eye by a slight degree of bending or distortion of the wire. The arrangement is preferably such that the handle may not be inserted or removed when in upright position, as shown in Fig. 4; but may be readily inserted or removed manually when it is in the inoperative position thereof shown in Fig. 1. This has the advantage of insuring against inadvertent dislocation of the handle in the event of excessive resistance to removal of the fuse carrying plug I9 from recess I8, due to an improper direction of pull upon the handle.

Base I9 is provided with four openings or passages |05, two of which are shown in Fig. 1, which permit access to the base portions of the respective jack blades, as by means of test jacks or wire ends, to permit testing of the range fuses while in position. The branch circuit fuses (not shown) when positioned in the respective recesses 20 to 23, inclusive, may likewise be tested without removal thereof from normal position,- by reason of the provision of angularly extending ways 0r slots 20, 2|, 22* and 23, which provide access to the respective shell contacts 24, as by means of a test jack,-the wiring terminals a, associated with the center contact screws or bolts 25, being exposed and readily accessible for engagement by the other jack of a fuse testing device of known form, when the main cover member 34 is removed.

As shown in Figs. 1 and 5, the portion |52l of base I5 in which cylindrical recesses 20 to 23 are formed is preferably offset inwardly from the forward face of the base, as represented by the forward end of the surrounding walls of recess I. Portion I5 of base I5 is further provided with an inwardly offset ledge I5b,which may be interrupted at a number of points to facilitate proper molding of said base, as shown in Fig. 1. Cover member 34 has attached to the inner surface thereof, as by means of rivets or spot welds, or both (not shown) a sheet metal guard member,the flat inwardly offset portion |06 (Fig. 5) is shaped to closely surround the contour of the forward end of portion I5 of base I5,-said flat portion being adapted to seat upon or rest adjacent to the aforementioned ledge I5". Guard member |06 is provided with parallel side wall portions, one of which is shown at I06,-said side wall portions extending closely adjacent to the surrounding wall of recess I8. The rear end wall |06b associated with guard member |06 completes the enclosure to prevent access to the wiring terminal members of the branch circuit fuses, so long as cover member 34 remains in position:

With the complete device mounted as shown in Figs. 1 and 5, the handle |04 will fall by gravity to the position thereof illustrated, after insertion of plug I9 into recess |8,-the front edge of the lower wall of recess I8 having grooves or notches IBI, I8I formed therein to accommodate handle |04 in a plane substantially ush with the forward end of the walls of said recess. Handle |04 in such position provides proper clearance for insertion or removal of the branch circuit fuses (see Fig. 1) When the device is mounted in a position 180 degrees reversed from that shown in Figs. l' and 5, handle |04 may be manually moved to and will remain in the position thereof shown in said flgures,whereby the auxiliary cover member 42 may be closed in the manner aforedescribed.

Also as shown in Figs. 1 and 5 a flber insulating plate |01 of rectangular contour underlies base I5 to insure proper electrical clearance between the conducting parts shown in Fig. 2 and the bottom wall 3| of the metal casing. A grounded neutral bus member |08 is interposed between insulating plate |01 and said bottom wall 3|,-the latter having an opening 3 In (Fig. 5) tp accommodate the flat cylindrical head |03 of a bolt the threaded shank |00* of which extends forwardly between the Shanks and I3| of a pair of bolts providing additional grounding terminals (Figs. 1 and 2). Said shanks |09, |30I and I3| take into tapped openings in the three channel-shaped terminal members 82 (Fig. 1) for cooperation with their associated wire clamping nuts 83h. Said shanks are electrically connected with each other, as by means of a metal strap or bus member |32 (Figs. 5 and l0).

A second bolt I|0 (Figs. 1 and 5) extends rearwardly through base I5 and takes into a tapped opening in bus member |08 to assist in rigidly attaching the latter to said base. Bus member |08 is provided at the lower end thereof (Figs. 1 and 5) with a portion |08a extending forwardly at a right angle. A neutral terminal member has a right-angled portion IIIa arranged parallel to portion I08,and a bolt |I2 has a threaded shank which penetrates portions I I I'l and I08 and takes into a tapped opening in end wall 30 to provide electrical and mechanical connection of said parts to each other and to the metal casing. One end of terminal member |I| overlies a ledge I5c rformed on base I5 to provide against bending or displacement of said member upon tightening of the four binding screws ||3 associated therewith. Member I I may be provided with an opening IIIb to accommodate the bared `Wired ends to provide a snubbing connection therefor prior to winding or looping the same around the shanks of binding screws I I3. As shown in Fig 2, the branch circuit fuse terminals 25a are preferably provided with similar openings 25b to provide snubbing connections for bared wire ends prior to winding or looping the same around the shanks of binding screws 25.

In Fig. 12 we have shown diagrammatically the circuit connections for the complete device,the various parts being designated by numerals corresponding to those employed in the other figures. Thus current ls supplied from lines L1, L2 and L12-the latter being the neutral wire, which is grounded through bus member |08. Upon closure of switch contacts 13 and 14 circuit will be pre-set for completion to the range upon closure of one or more of the usual range switches (not shown) ,--linefL2 being thus connected through range fuse I I4 with range lead R2; line L1 being connected through range fuse ||5 with range lead R1; and the grounded neutral L3 being permanently connected with the neutral range lead R3. Closure of contacts I3 and 14 likewise pre-sets the respective pairs of branch circuits IIS, II1 and II8, IIB for completion to suitable translating devices (not shown) upon operation of suitable switches or plugs associated with the latter,-it being noted that each branch circuit includes therein a grounded neutral connection.

In Fig. 14 we have shown an insulating base |20, which isy slightly modified with respect to base I5 aforedescribed; base |20 being provided with a downwardly opening pair of opposed grooves (one of which is shown at |2I) in a passage |22 which opens at one end to the outer surface of base |20 and at its other end communicates with recess |23. A handle member or operating lever |24, having plate |25 pivotally attached thereto at |26, is inserted upwardly through passage |22, with the pvot pin |21 in position in said lever,- pin |21 being adapted to enter the opposed grooves, such as I2 I, to pivotally bear against the closed upper ends of the latter. When the contacts 13 and 14 are in assembled position they will normally act through engagement thereof with plate |25 to retain pin |21 against displacement from said slots I2 I. By the arrangement just de- 4 scribed, we facilitate assembly of the switch parts,

while at the same time obviating the necessity for use of the metal plate 64 and screws 66 shown in Figs. 6 and 7.

The advantages of our invention will be apparent to those skilled in the art. By our novel arrangement the necessity for use of main fuses is obviated,thus avoiding the principal source of injurious heat in devices of this character. In practice the stationary contacts ll, 12, the part 14a, 'I4b of contact 14, and the corresponding part of contact 13, are provided with a silver electroplate of suitable thickness to insure high current-carrying efiiciency oi' the switch, despite infrequent operation of the latter.

'I'he main switch is operated from the exterior of the casing, with an operating lever like the toggle levers ordinarily employed on switches for home lighting circuits. The familiarity of the ordinary householder with this type of operating means, makes the complete device acceptable and easily understood by the user, thus resulting in a great reduction in the number of service calls required.

The aforedescribed arrangement provides for installation of the complete device in normal position (Figs. 1 and 5) or in an inverted position. In either event the auxiliary cover member 42 stays opened or closed, as desired; and the on and oif indications read correctly. Solid porcelain barriers l28, l29 (Fig. 1) are provided between the solderless terminals associated with the aforementioned sets of

bolts

16a, 95 and 8l, 94,-- thus preventing the possibility of short circuits.

The jack blades 97 of the range fuse pullout are preferably silver plated, and the same as shown are separate from the respective fuse clips 98,- thus reducing contact temperature to a minimum.

As shown in Fig. 2, the left-hand pair of center contact screws 25, 25 are electrically connected with each other through the medium of bus member 26a-which is likewise electrically connected with bus member 8l. Similarly, the right-hand pair of center contact screws 25, 25 are electrically connected with each other through the medium of bus member 26b,-which is electrically connected with bus member 92.

What we claim as new and desire to secure by Letters Pat-ent is:

l. In a service control device, in combination, a metal casing having bottom, side and end walls and an open front, a main cover member, said main cover member having formed therein a relatively large opening, an unfused main switch of the slow-break type positioned within said casing and having an operating member projecting through said main cover member, means comprising a plurality of sets of branch circuit fuse receiving contacts arranged at one side of said switch, a fuse pullout device arranged in parallel relationship to said switch and said sets of branch circuit fuse receiving contacts, said pullout device comprising a plug of substantially rectangular contour, said plug having clips attached thereto to receive and retain a pair of cartridge type fuses, a single molded insulating base adapted to support all of the elements aforementioned, said base having a recess to accommodate said plug, said plug and said sets of branch circuit fuse receiving contacts being readily accessible through said opening, vand an auxiliary cover member attached to said main cover member and movable at will with respect thereto to open and close said opening.

2.. In a service control device, in combination, a sheet metal casing having bottom, side and end walls and an open front, a main sheet metal cover member, said main cover member having formed therein a slot of relatively small dimensions and a substantially rectangular opening of relatively large dimensions, a one-piece molded insulating base positioned within said casing, a switch mechanism supported by said base adjacent to one end of the latter, said switch mechanism having an oscillatable operating member extending outwardly through said slot, a fuse pullout device carried by said base at one side of said switch mechanism in a plane parallel to the plane of oscillation of said operating member, said pullout device including a plug having clips thereon to receive and retain a pair of cartridge type fuses in end to end relationship to each other, four sets o! branch circuit fuse receiving contacts arranged in a line at one side of and parallel to said fuse pullout, said fuse pullout and said branch circuit fuse receiving contacts being readily accessible through said relatively large opening, a guard member surrounding portions of said sets of branch circuit fuse receiving contacts to insure against access to the wiring terminal members associated with the latter, and an auxiliary cover member hinged to said main cover member and f movable with respect thereto into or out of overlapping relation to said relatively large opening.

3. In a device of the character described, in combination, a molded insulating base having a relatively long substantially rectangular recess formed therein and opening to the front surface thereof, the bottom wall of said recess having a plurality of pairs of openings formed therein, the respective openings being spaced from each other longitudinally of said recess, contacts positioned within the respective openings below the upper surface of said bottom wall, whereby said contacts are concealed, a molded insulating plug member of rectangular contour adapted to fit within said recess to provide for substantially complete closure of the latter, said plug member having jack blades adapted to enter said openings for engagement with the respective contacts, fuse clips electrically and mechanically connected with the respective jack blades, said fuse clips being adapted to receive and retain a pair of cartridge type fuses in end to end relationship to each other, said base having a plurality of relatively small substantially cylindrical recesses formed therein in alinement with each other along one longitudinal side of said rst mentioned recess and below the upper surface of the latter, center and screw shell contacts positioned within said cylindrical recesses to accommodate a corresponding number of branch circuit fuse plugs, a switch carried by said insulating base at the other longitudinal side of said rst mentioned recess and having an operating member projecting beyond the front surface of said base, a main cover member having a relatively small opening formed therein to provide clearance for said switch operating member and a relatively large opening formed therein to provide access to all of said recesses, and an auxiliary member carried by said main cover member and movable with respect thereto to cover or uncover said relatively large opening.

4. In a device of the character described, in combination, a molded insulating base having a relatively long substantially rectangular recess formed therein and opening to the front surface thereof, the bottom wall of said recess having a plurality of pairs of openings formed therein, the respective openings being spaced from each other longitudinally of said recess, contacts positioned within the respective openings below the upper surface of said bottom wall, whereby said contacts are concealed, aV molded insulating plug member of rectangular contour adapted to seat within said recess to provide for substantially nected with the complete closure of the latter, said plug member having jack blades adapted to enter said openings for engagement with the respective contacts, fuse clips electrically and mechanically connected with the respective jack blades, said fuse clips being adapted to receive and retain a pair of cartridge type fuses in end to end relationship to each other, said base having a plurality of relatively small substantially cylindrical recesses formed therein in alinement with each other along one longitudinal side of said first mentioned recess and below the upper surface of the latter, center and screw shell contacts positioned within said cylindrical recesses to accommodate a corresponding number of branch circuit fuse plugs, a switch carried by said insulating base at the other longitudinal side of said iirst mentioned recess and having an operating member projecting beyond the front surface of said base, a main cover member having a relatively small opening formed therein to provide clearance for said switch operating member and a relatively large opening formed therein to provide access to all of said recesses, an auxiliary member carried by said main cover member and movable with respect thereto to cover or uncover said relatively large opening, and said main cover member and said auxiliary member being cooperatively formed to provide for attachment of a sealing element thereto.

5. In a device of the character described, in combination, a molded insulating base having a relatively long substantially rectangular recess formed therein and opening to the front surface thereof, the bottom wall of said recess having a plurality of pairs of openings formed therein, the respective openings being spaced from each other longitudinally of said recess, contacts positioned within the respective openings below the upper surface of said bottom wall, whereby said contacts are concealed, a molded insulating plug member of rectangular contour adapted to fit within said recess to provide for substantially complete closure of the latter, said plug member having jack blades adapted to enter said openings for engagement with the respective contacts, fuse clips electrically and mechanically conrespective jack blades, said fuse clips being adapted to receive and retain a pair of cartridge type fuses in end to end relationship to each other, said base having a plurality of relatively small substantially cylindrical recesses formed therein in alinement with each other along one longitudinal side of said rst mentioned recess and below the upper surface of the latter, center and' screw shell contacts positioned within said cylindrical recesses to accommodate a corresponding number of branch circuit fuse plugs, a switch carried by said insulating base at the other longitudinal side of said rst mentioned recess and having an operating member projecting beyond the front surface of said base, a main cover member having a relatively small opening formed therein to provide clearance for said switch operating member and a relatively large opening formed therein to provide access to all of said recesses, an auxiliary member carried by said main cover member and movable with respect thereto to cover or uncover said relatively large opening, and said main cover member having a metal guard member attached thereto and oiset downwardly therefrom, said guard member being adapted to overlie said insulating base adjacent to said cylindrical recesses to prevent access to wiring terminal members associated with the latter when said main cover member is in its assembled position.

6. In a device of the character described, in combination, a molded insulating base having a relativelylong substantially rectangular recess formed therein and opening to the front surface thereof, the bottom Wall of said recess having a plurality of pairs of openings formed therein, all of the respective openings being spaced from each other longitudinally of said recess, resilient contacts positioned within the respective openings below the upper surface of said bottom wall, whereby said contacts are concealed, a molded insulating plug member of relatively long rectangular contour adapted to seat within said recess to provide for substantially complete closure of the latter, said vplug member having jack blades adapted to enter said openings for engagement with the respective contacts, and fuse clips electrically -and mechanically connected with the respective jack blades, all of said fuse clips being arranged in longitudinal alinement and the same being adapted to receive and retain a pair of cartridge type fuses in end to end relationship to each other.

7. In a device of the character described, in combination, a one-piece molded insulating base having a relatively long substantially rectangular recess formed therein and opening to the front surface thereof, the bottom wall of said recess having a plurality of pairs of openings formed therein, all of the respective openings. being spaced from each other longitudinally of said recess adjacent to one side wall of the latter, resilient contacts positioned within the respective openings below theupper surface of said bottom wall, whereby said contacts are concealed, a one-piece molded insulating plug member of corresponding rectangular contour adapted to fit within said recess in a relationship substantially flush with the front surface of said base to provide for substantially complete closure of said recess. said plug member having jack blades attached thereto and alined with said openings to enter the latter for engagement with the respective contacts in only one relative position of said plug member an'd base, fuse clips electrically and mechanically connected with the respective jack blades, all of said fuse clips being arranged in longitudinal alinement and the same being adapted'to receive and retain a pair of cartridge type fuses in end to end relationship to each other, and a handle carried by said plug member to facilitate insertion and withdrawal of the latter, said handle being movable to an inactive position substantially flush with the outer surfaces of said plug member and the walls of said recess.

8. As an article of manufacture, a fuse-carrying plug member comprising a molded insulating base of relatively long substantially rectangular contour, two pairs of jack blades arranged in a common plane along one longitudinal side of the inner surface of said base, cartridge type fuse clips associated with the respective jack blades, a bolt and a nut individual to each jack blade and its associated fuse clip for detachably securing the same to each other and to said base, said base having a transverse barrier formed integrally therewith and positioned between said pairs of jack bladesv and fuse clips, and a lug formed integrally with said base and offset from 'a median line of the latter, said lug being adapted to cooperate with a recess of suit- Aable form to prevent insertion of said plug member in more than one relation.

9. As an article of manufacture, a fuse-carrying plug member comprising a molded insulating base of relatively long substantially rectangular contour, two pairs of jack blades arranged in a common plane along one longitudinal side of the inner surface of said base, cartridge type fuse clips associated with the respective jack blades, means individual to each jack blade and its associated fuse clip for securing the same to each other and to said base, said base having a transverse barrier formed integrally therewith and positioned between said pairs of jack blades and fuse clips, a lug formed integrally with said base and offset from a median line of the latter, said lug being adapted to cooperate with a recess of suitable form to prevent insertion of said plug member in more than one relation, and said insulating base having four test passages formed therein and leading from the outer surface thereof to the respective jack blades, whereby fuses carried by the respective pairs of clips may be tested while said pairs of jack blades are in a. normal relation providing for completion of a circuit or circuits controlled thereby.

l0. As an article of manufacture, a plug member adapted to receive and retain a pair of cartridge fuses in end to end relationship to each other, said plug member comprising a single molded insulating base of relatively long rectangular contour, said base having four substantially rectangular recesses arranged in longitudinally spaced relation at the 'inner surface thereof, a corresponding number of bolts having portions embedded in said base and having threaded Shanks projecting from the respective recesses, jack blades having base portions bent at substantially right angles thereto and positioned within said recesses, substantially U-shaped clips for ferrule type cartridge fuses, the fiat base portions of said clips being positioned within said recesses in superimposed relation to the base portions of said jack blades, said Shanks penetrating the base portions of said jack blades and said clips, nuts cooperating with said shanks to clamp said parts in assembled relation, an insulating barrier formed integrally with said first mentioned base and extending transversely between the longitudinally spaced pairs of jack blades and clips, a pair of metal eye members secured to said insulating base and exposed at the outer surface of the latter, and a handle comprising a resilient wire member of substantially U-shape, the arms of which have bent ends which are insertable into and removable from said eye members at will upon bending of at least one of said arms.

11. As an article of manufacture, a plug member adapted to receive and retain a pair of cartridge fuses in end to end relationship to each other, said plug member comprising a single molded insulating base oi relatively long rectangular contour, said base having four substantially rectangular recesses arranged in longitudinally spaced relation at the inner surface thereof, a corresponding number of bolts having portions embedded in said base and having threaded shanks projecting from the respective recesses, jack blades having base portions bent at substantially right angles thereto and positioned within said recesses, substantially U-shaped clips for ferrule type cartridge fuses, the fiat base portions of said clips being positioned within said recesses in superimposed relation to the base portions of said jack blades, s aid Shanks penetrating the base portions of said jack blades and said clips. nuts cooperating with said Shanks to clamp said parts in assembled relation, an insulating barrier formed integrally with said first mentioned base and extending transversely between the longitudinally spaced pairs of jack blades and clips, a pair of metal eye members secured to said insulating base and exposed at the outer surface of the latter, and a handle comprising a resilient wire member of substantially Ushape, the arms of which have bent ends which are insertable into and removable from said eye members at will upon bending of at least one of said arms, the bent ends of said arms being so related to the outer surface of said insulating base as to substantially prevent removal of the former from said eye members when said handle is in operative position.

12. In a device of the character described, in combination, a metal casing having bottom, side and end walls and an open front, a main cover member removably attached to said casing at the front thereof, said main cover member having a relatively large opening formed therein and an inwardly offset flange surrounding said opening, an auxiliary cover member adapted to seat against said flange in a relation substantially flush with the outer surface of said main cover member, a pair of hinges for connecting said auxiliary cover member to said main cover member at one side of said opening, and a single spring metal strip rigidly secured to the inner surface of said auxiliary cover member between said hinges, said strip cooperating with the edge of said flange at said side of the opening to yieldably retain said auxiliary cover member in its closed orA its opened position, said auxiliary cover member when opened providing free access to electrical devices positioned within said casing.

13. In a device of the character described, in combination, a. metal casing having bottom, side and end walls and an open front, a main cover member removably attached to said casing at the front thereof, said main cover member having a relatively large opening formed therein and an inwardly offset flange surrounding said opening, an auxiliary cover member adapted to seat against said flange in a relation substantially flush with the outer surface of said main .cover member, a pair of hinges for connecting said auxiliary cover member to said main cover member at one side of said opening, a single spring metal strip rigidly secured to the inner surface of said auxiliary cover member between said hinges, said strip cooperating with the edge of said flange at Said side of the opening to yieldably retain said auxiliary cover member in its closed or its opened position, said auxiliary cover member when opened providing free access to electrical devices positioned within said casing, and said auxiliary cover member being provided at the edge thereof opposite to said hinges with integral lugs bent outwardly to arcuate form in cross section, to thereby facilitate manual opening of said auxiliary cover member.

14. In a device of the character described, in combination, a metal casing having bottom, side and end walls and an open front, a main cover member removably attached to said casing at the front thereof, said main cover member having a relatively large opening formed therein and an inwardly offset flange surrounding said opening, an auxiliary cover member adapted to seat against said flange in a relation substantially fiush with the outer surface of said main cover member, a pair of hinges for connecting said auxiliary cover` member to said main cover member at one side of said opening, a single spring metal strip rigidly secured to the inner surface of said auxiliary cover member between said hinges, said strip cooperating with the edge of said flange at said side of the opening to yieldably retain said auxiliary cover member in its closed or its opened position, said auxiliary cover member when opened providing free access to electrical devices positioned within said casing, said auxiliary cover member being provided at the edge thereof opposite to said hinges with integral lugs bent outwardly to arcuate form in cross section, to thereby facilitate manual opening cf said auxiliary cover member, and said main cover member having non-offset portions of arcuate form underlying said lugs to minimize the apparent degree of projection of the latter when viewed from the' front.

15. In a device of the character described, in combination, a metal casing having bottom, side and end walls and an open front, a main cover member removably attached to said casing at the front thereof, said main cover member having a relatively large opening formed therein and an inwardly offset fiange surrounding said opening, an auxiliary cover member adapted to seat against said flange in a relation substantially flush with the outer surface of said main cover member, a pair of hinges for connecting said auxiliary cover member to said main cover member at one side of said opening, a single spring metal strip rigidly secured to the inner surface of said auxiliary cover member between said hinges, said strip cooperating with the edge of said flange at said side of the opening to yieldably retain said auxiliary cover member in its closed or its opened position, said auxiliary cover memberwhen opened providing free access to electrical devices positioned within said casing, said auxiliary cover member being provided at the edge thereofv opposite to said hinges with integral lugs bent outwardly to arcuate form in cross section, to thereby facilitate manual opening of said auxiliary cover member, said main cover member having non-offset portions of arcuate form underlying said lugs to minimize the apparent degree of projection of the latter when viewed from the front, said main cover member having an integral, upstanding, perforated lug, and said auxiliary cover member having a relatively small opening to accommodate said lug to provide for attachment of sealing means of suitable form.

16. In a service control device, in combination, a metal casing having bottom, side and end walls and an open front, a main cover member, said main cover `member having formed therein a relatively large opening, an unfused main switch of the slow-break type positioned within said casing and having an operating member projecting through said main cover member, means comprising a plurality of sets of branch circuit fuse receiving contacts arranged at one side of said switch, a fuse pullout device arranged in parallel relationship to said switch and said sets of branch circuit fuse receiving contacts, said pullout device having an elongated substantially rectangular recess and a plug of corresponding contour adapted to seat therewithin, said plug having clips attached thereto to receive and retain a pair of cartridge type fuses in end to end relationship to each other, a single molded insulating base adapted to support all of the elements aforementioned, said fuse pullout and said sets of branch circuit fuse receiving contacts being readily accessible through said relativcly large opening, and an auxiliary cover member attached to said main cover member and movable at will with respect thereto to open and close said relatively large opening.

17. In a service control device, in combination, a sheet metal casing having bottom, side and end walls and an open front, a main sheet metal cover member, said main cover member' having formed therein a slot of relatively small dimensions and a substantially rectangular opening of relatively large dimensions, a one-piece molded insulating base positioned within said casing, a. switch mechanism of the slow-break type supported by said base adjacent to one end of the latter, said switch mechanism having an oscillatable operating member extending outwardly through said slot, a fuse pullout device carried by said base at one side of said switch mechanism in a plane parallel to the plane of oscillation of said operating mcmber,'said pullout device including a plug having clips thereon to receive and retain a pair of cartridge type fuses in end to end relationship to each other, a plurality of sets of branch circuit fuse receiving contacts arranged in a line at one side of and parallel to said fuse pullout, said fuse pullout and said branch circuit fuse receiving contacts being readily accessible through said relatively large opening, said branch circuit fuse rcceiving contacts being offset inwardly from the forward end of said fuse pullout device, a guard member carried by said main cover member at the inner surface thereof and surrounding poi'- tions of said sets of branch circuit fuse receiving contacts to insure against access to the wiring terminal members associated with the latter while said main cover member is in position, and an auxiliary cover member hinged to said main cover member and movable with respect thereto into or out of overlapping relation to said relatively large opening, said auxiliary cover member having a single spring member associated therewith to yieldably resist certain movements thereof in opposite directions respectively. y

18. In a device of the character described, in combination, a molded insulating base having a relatively long substantially rectangular recess formed therein and opening to the front surface thereof, said recess being adapted to accommodate a plurality of electric fuses and having means to provide suitable electrical connections for the latter, said base having a plurality of relatively small substantially cylindrical recesses formed therein in alinement with each other along one longitudinal side of said first mentioned recess and below the upper surface of the latter, center and screw shell contacts positioned Within said cylindrical recesses to accommodate a corresponding number of branch circuit fuse plugs, a switch carried by said base at the other longitudinal side of said first mentioned recess and having an operating member projecting beyond the front surface of said base, a main cover member having a relatively small opening formed therein to provide clearance for said switch operating member and a relatively large opening formed therein to provide access to all of said recesses, an auxiliary member carried by said main cover member and movable with respect thereto to cover or uncover said relatively large opening, and said main cover member having a metal guard member attached thereto and offset downwardly therefrom, said guard member being adapted to overlie said insulating base adjacent to said cylindrical recesses to prevent access to wiring terminal members associated with the latter when said main cover is in its assembled position.

19. In a service control device, in combination, a sheet metal casing having bottom, side and end walls and an open front, a main sheet metal cover member, said main cover member having formed therein a substantially rectangular slot of relatively small dimensions and a substantially rectangular opening of relatively large dimensions, a one-piece molded insulating base positioned within said casing, a fuseless main switch of the slowlbreak type supported by said base adjacent one end of the latter, said switch having an oscillatable operating member extending outwardly from the iront surface of said base, the walls of said slot providing oscillating clearance for said operating member, said base having a plurality of substantially cylindrical recesses formed therein and arranged in a line parallel to the plane of oscillation of said operating member, a set of branch circuit fuse receiving contacts positioned Within each of said recesses, said branch circuit fuse receiving contacts being readily accessible through said relatively large opening, a metal guard member rigidly attached to the inner surface of said main cover member, said guard member having an inwardly offset portion surrounding portions of said branch circuit fuse receiving contacts to insure against access to the usual wiring terminal members associated with the latter while said main cover member is in assembled relation to said casing, an auxiliary metal cover member hinged to said main cover member and movable with respect thereto into or out of overlapping relation to said relatively large opening, and a single sheet metal spring member rigidly attached to said auxiliary cover member and cooperable with a portion of said main cover member to yieldably retain said auxiliary cover member in its open or its closed position regardless of the mounted position of the complete device.

RALPH A. MILLERMASTER. ALEX A. WRITZMANN.