US2193201A - Fuse pull-out device - Google Patents

Description

March l2, 1940. n. A. MILLERMASTER FUSE PULL-OUT DEVICE 5 sheds-'sheet 1 Filed Janf 13, 1958 lll n; na

50 5.25/ lll us sz 5/ 5o Mardi 12, 1940- R. AMILLERMASTER FUSE PULL-OUT DEVICE Filed Jan. 13, 195.8 3 Sh'eets-Sheej 1?,`

Mardi 12, 1940- R. A. MILLERM'ASTER FUSE PULL-OUT DEVICE .Filed Jan. 13. 193s s sheets-sheet 5 Patented Mar. 12, 1940 FUSE PULL-OUT DEVICE Ralph A. Millermaster, Milwaukee, Wis., assigner to Cutler-Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Application January 13, 1938, Serial No. 184,715

9 Claims.

pull-out devices.

A primary Aobject of the invention is to provide acombination main and range fuse pull- 5 out device of novel form.

Another object -is to provide a device of the character aforementioned, embodying main and range fuse carrying plugs, with means to insure against insertion of the range fuse carrying plug l into the receptacle normally adapted to accommodate the main fuse carrying plug.

Another object is to provide a combination main and range fuse plug switching device of the character aforementioned wherein means,

l including the aforementioned means to insure against interchangeability of the range fuse plug, are provided for effecting on and ofi positioning of the fuse plugs within their respective receptacles.

a0 Another object is to generally improve the details of construction of the parts of such fuse pull-out devices and the manner of supporting the same within the enclosing casing.

Another object is to provide a novel form oi handle for such fuse plugs or pull-outs.

Another object is to provide novel means for facilitating wiring of such devices.

' Another object is to provide a novel arrangement of branch circuit fuse receptacles for asso- 80 ciation with said main and range fuse pullouts.

Other objects and advantages of the invention will hereinafter appear.

The accompanying drawings illustrate a preferred embodiment of the invention which will now be describedit being understood that the embodiment illustrated vis susceptible of modification in vrespect of certain structural details without 'departing from the spirit and scope of the invention as defined by the appended claims.

In the drawings,

Figure 1 is a top plan View (half-scale) of a molded insulating base providing main and range 'fuse plug receptacles, and an associated insulating base providing receptacles for a plurality of branch circuit fuse plugs, the contact and wiring terminal elements being shown in assembled relation.

Fig. 2 is a bottom plan view of the parts shown in Fig. 1, illustrating the manner of attaching said parts to the base members, and the manner in which certain of said parts are electri cally connected.

Fig. 3 is a top plan view of the range fuse (Cl. 20G-114) This invention relates to improvements in fuse pull-out, which is adapted for insertion only in the receptacle at the right hand side of Fig. 1.

Fig. 4 is a bottom plan view of the pull-out shown in Fig. 3, illustrating the form and arrangement of the grooves or-recesses which pro- 5 vide for on and off positioning thereof within the right hand recess of Fig. 1, and which also insure against operative positioning thereof Within the left hand recess of Fig. 1.

Fig. 5 is a sectional' view on the line 5--5 of 10 Fig. 1, illustrating the manner of supporting the device within an enclosing casing of suitable form.

Fig. 6 is a fragmentary sectional view (full scale) on the line 6-6 of Fig. 5, the neutral bus 15 member being omitted, and the range fuse plug being turned 180 degrees to limit the degree of insertion thereof, for oif position.

Fig. 7 is a fragmentary top plan view of the enclosing casing, illustrating the manner of at- 20 taching the metal supporting plate for the insulating base members, and illustrating thel form of the neutral bus member and the manner of attaching the same to the bottom wall of the casing. 25

Fig. 8 is a detail perspective view of a fragment of a bus member or conducting strip having my improved wiring terminal member or clamp rigidly attached thereto.

Fig. 9 is a fragmentary bottom plan view of a 30 pull-Out quite similar to that illustrated in Fig.

4, but showing the modified form of grooves or recesses to provide for on and ofi positioning thereof within the left hand recess in Fig. 1, and 35 Fig. l0 is a schematic and diagrammatic view illustrating the manner of eiecting the circuit connections for the various elements of the complete device.

Referring to the drawings, the numeral l5 40 designates a base which is molded from a suit able insulating material, such as grey porcelain. Base l5 is provided in its front face with a pair of relatively large substantially rectangular recesses I6 and I1, the bottom Walls of said ie- 45 cesses being respectively provided with openings or passages I8 and I9 similarly positioned adjacent to the four corners thereof. Located beneath the bottom walls of said recesses and alined with the respective openings or passages are a corresponding number of stationary conto facilitate insertion therebetween of the ends of contact prongs 2l of like form associated with the fuse pull-outs, as hereinafter described. The arms of contacts 2l) are preferably formed from suitable lengths of strip material, such as phosphor bronze, and said contacts are secured in position by bolts 22, the heads of which are positioned in countersunk recesses in the bottom walls of recesses i6 and I1, and nuts 23, which clamp the contacts against ledges offset upwardly from the rear surface of base I5.

As best illustrated in Figs. 2 and 6 certain of said bolts 22 and nuts 23 act to clamp their respectively associated contacts 20 in mechanical and electrical engagement with suitable copper bus members of different lengths, which are respectively numbered 24, 25, 26 and 21. As shown in Fig. 2, bus members 25 and 26 are electrically connected with each other through the medium of a bus member 28, these parts being mechanically attached to the branch circuit fuse block 29, which is preferably molded separately from base I5, but of like material. The attaching means for these parts comprise bolts 30 and 3| of like form, the heads of which are adapted to form the center contacts of two of the branch circuit fuse sockets, as shown in Fig. 1, nuts being provided for said bolts, as shown in Fig. 2,

.to clamp the parts in assembled relation. Like bolts 32 and 33 and their associated nuts act to clamp bus members 24 and 21 to block 29, the heads of said bolts providing center contacts for the other branch circuit fuse sockets, Fig. l.

Bus members 24 and 21 are electrically connected by a bus member or strap 34 (Fig. 2) which is retained in assembled position by a pair of bolts 35a and 36a, the heads of which are located in countersunk recesses in the bottom walls of recesses I1 and I6 (Fig. 1). The branch circuit fuse sockets comprise screw shell contacts 35, which may be of usual form, each having a wiring terminal plate 36 and binding screw 31 associated therewith. As indicated in Figs. 2 and 5, the bus members 24 to 21 provide a substantial rigid mechanical connection between base I5 and block 29. 'Attached to basev I5 at the end of the latter remote from the branch circuit fuse sockets, as by means of a corresponding number of the bolts 22, are four relatively short bus members 38 of like form, as shown in Figs. 1, 2 and 5.

Each of the bus members 38 and bus members 25 and 21 has attached thereto a solderless Wiring terminal device of the character best illustrated in Fig. 8. As shown inv this figure, each bus member has portions of its sides cut away to provide a head 39, and a neck 4I) of a width and length corresponding rather closely to the internal width and the length, respectively, of a hollow metal member 4I of substantially rectangular form in cross section. Member 4I is preferably formed by cutting or sawing the desired length thereof from a seamless steel tube of substantially rectangular form in cross section, as illustrated. One wall of member 4I is provided With a relatively large tapped opening to accommodate the threaded shank of a screw 42,

the diameter of which shank is preferably only slightly less than the width of the rectangular opening or passage through member 4l, as best illustrated at the left hand side of Fig. 5.. The head of each screw 42 is preferably of hexagonal or other polygonal contour, to provide for operation thereof by a suitable wrench, and the same `is also preferably provided with a kerf to alteraioaaoi natively provide for operation thereof by a screw driver. The lower end of each screw shank is preferably at, to provide a relatively large clamping area.

With reference to Fig. 8, it is to be understood that member 4I is initially tilted in one direction or the other (with screw 42 omitted or sufliciently withdrawn to permit clearance for the head 39 at diagonally opposite sides of the opening in said member). Member 4l is then turned to upright position, as shown in Fig. 8, and while the neck 40 is held against the inner surface of the lower wall of the opening in member 4I, a pair of integral lugs, such as 43, are swaged or bent inwardly from opposite side edges of the bus member (such as 38) into engagement with the exterior walls of member 4I and opposite ends 33a of head 39 are swaged against the forward end of said member 4l to rigidly and permanently secure the latter to the bus member. The exposed surface of neck 40 within member 4l is preferably provided with a series of grooves and ridges, or is otherwise roughened, to provide a gripping surface for the conductor or wire pressed thereagainst by tightening of the clamping screw 42. As will be understood, the'flat lower end of the shank of screw 42 acts to clamp a conductor tightly and directly against the copper bus member (such as 38); and hence both member 4I and screw 42 may be formed of steel, to insure proper strength and durability of these parts. The solderless wiring terminal device shown in Fig. 8, including parts 38, 4I and 42, forms a portion of the subject matter of my copending application, Serial No. 261,527, led March 13, 1939.

As best illustrated in Fig. 1 the recess I6 is provided on the longer sides thereof With a pair of integral alined ribs 44 and 45, said ribs extending from the bottom wall of said recess to a plane slightly above the upper edge of the side walls of the recess, as shown at the right hand side of Fig. 6. With reference to Fig. 1, it will be noted that ribs 44 and 45 are located nearer to the upper end wall of recess I6 than to the lower end wall thereof, and that said ribs extend laterally into recess I6 to like degrees. The range fuse carrying plug 46 (Figs. 3 and 4) is provided in its inner surface with recesses or depressions 41 and 48 to respectively register with and accommodate the upper end portions of ribs 44 and 45, when said plug, in the relation shown in Fig. 3 is fully inserted into recess I6, Fig. 1, to the On position thereof illustrated in Fig. 5. Plug 46 is preferably provided with the legend On, as shown at 49 to indicate closed circuit positioning of plug 46 under these conditions-assuming insertion of the proper range capacity fuses (not shown) within the pairs of longitudinally alined cartridge type fuse holding clips 50, 50 and 50, 50 (Fig. 4). Each clip 50 has associated therewith a contact prong 2I and said prongs and clips are attached to the insulating base of the plug 46 by means of bolts or screws 5I and nuts 52. U

However, if plug 46 is turned through an angle of 180 degrees, from the position thereof shown in Fig. 3, the recesses 48, 41 in the inner surface thereof will not register with the respective ribs 44, 45, wherefore the inner surface portions 53 and 511 of said plug will rest upon the upper ends of ribs 44 and 45 to restrain the Contact prongs from engagement with contacts 29, as shown at the right hand side of Fig. 6. Plug 46 is pref-- erably provided with the legend Off, as shown at 55, which is located in indicating positioning under these conditions.

Referring again to Fig. l, it will be noted that recess I 1 is provided with a pair of ribs 56 and 51, which are alined with the ribs 44, 45. However, ribs 56, 51 extend laterally into recess I1 to a greater extent than the ribs 44, 45 extend into recess I6. inasmuch as the recesses 41, 48 in the inner surface of plug 46 do notvhave a lateral depth sufliciently large to accommodate ribs 56, 51, it follows that the range fuse plug 46 cannot in either rotary position thereof be inserted into recess |1 to a degree sufficient to effect engagement of contact prongs 2| with the contacts 20 positioned below the bottom wall of saidrecess. This feature is of great practical importance, since it prevents accidental or careless insertion of the range fuse carrying plug 46 into circuit com pleting relation to the recess I1 which is intended to recess only the main fuse carrying plug-r a fragment of which is shown at 58 in Fig. 9 it being understood, of course, that the range fuses employed will have a substantially lower rating or current carrying capacity than the main fuses.

With reference to Figs. 9 and 6, it is to be Aunderstood that fuse carrying plug 58 is substantially like plug 46 aforedescribed, except that plug 58 is provided with recesses 59 and 66 of sufficient lateral depth to accommodate ribs 56 and 51, respectively, whereby plug 58 in one position thereof is insertable into recess |1 to a degree sufficient to effect engagement of contact prongs 2| with contacts 20, as shown at the left hand side of Fig. 6.

It will be understood that main fuse plug 58 might be unintentionally inserted in a corresponding relation into circuit completing position with respect to the recess I6 for the range fuse plug 46, but such unintentional insertion would not endanger the main fuses carried by plug 58. Moreover, under these conditions circuit could not be completed from the main line contacts associated with recess |1, due to the aforedescribed inability to insert the range fuse carrying plug 46 into circuit completing relation to said recess I1. The error would therefore require to be corrected as a prerequisite to completion of the circuit from the main lines or source' of current supply.

As shown at the left hand side of Fig. 6, the Contact prongs 2| and fuse holding clips 50 are retained in assembled relation to plug 58 by means of screws or bolts and nuts 52 like those aforedescribed. Due to the relatively high current carrying and controlling capacity of the fuses to be carried by plug 58, I prefer to interpose between the inner surface of plug 58 and each of the right angled portions of the contact prongs 2| a iiber strip 59 of a width at least as great as the width of the respective prongs, the free ends of said fiber strips extending downwardly along the respective contact prongs 2|, and being secured to the latter, as by means of rivets or eyelets 60.

It follows that upon insertion or withdrawal of plug 58 with respect to recess I1 there is-no possibility that the users hands or fingers will come in contact with the prongs 2| when current is passing through the latter. It is to be understood that after nal assembly of the parts, the countersinks or recesses within which the various screw heads 22 and 5I are located will be lled with wax or other insulating sealing material to provide a complete dead-front for the bottom walls of recesses |6 and |1 and for the exposed surfaces of fuse carrying plugs 46 and 58.

Plugs 46 and 58 are provided with handles of novel form. Each handle comprises a rod orA shaft 6| of square form in cross section, as shown 5 in dotted lines in Figs. 4 and 9, preferably formed of cold rolled steel. Said rods are insertabl'e upwardly and slidable within centrally located passages of corresponding cross section formed in plugs 46 and 58. Each rod 6| is provided at its lower end with an enlargement or head 62 which limits the upward movement thereof with respect to its associated plug. Each rod 6| is also provided at its upper end with cut-away portionsY at two opposite sides thereof to provide an extension of rectangular cross section, but of reduced width-as shown in dotted lines at 63 in Fig. 5--to t within an opening of corresponding shape provided in the flat metal finger grip member 64, and said extension is then split, swaged or upset over the upper surface of member 64, as shown at 65, to rigidly attach said members to each other. During assembly of the handle parts a coiled compression spring 66 is interposed between the lower surfaceof member 64 and the upper surface of the respective plug 46 or 58, whereby member 64 is normally biased to its upper extreme position, as shown in Fig. 5 and at the left hand side of Fig. 6.

As shown in Figs. 5 and 6 the metal casing or box 61 is provided with a cover 68 which is 'removably attached thereto as by means of 1| is preferably provided with an integral loop 15 and member 14 is provided with an opening (not shown) to accommodate the usual wire, the ends of which may be sealed together, for the purpose of sealing member 1I in closed position.

The auxiliary cover member 1| is preferably bulged outwardly as shown, to provide clearance for the rod 6| and member 64 when the fuse carrying plug is in circuit completing position, as illustrated at the left hand side of Fig. 6, and to likewise provide clearance for rod 6|, member 64 and a portion of the fuse carrying block, such as 46, when the latter is out of circuit completing position, or in Oilfposition as shown at the right hand side of Fig. 6.

'I'he' aforementioned block I5 is attached to a flat sheet metal plate 16 (Figs. 5 to 7) as by means of four screws 11V the heads of which are locatedjin recesses 1,8 and the threaded Shanks of which penetrate somewhat elliptical passages 19 provided in said block, and take into tapped openings 80 provided in plate 16. Block 29 is attached to plate 16 by screws like 11, the heads of which are located in recesses 8| (Fig. 1) and the threaded Shanks of which penetrate the somewhat elliptical passages 82 and take into tapped openings 83 provided in plate 16 (Fig. 7).

As shown in Fig. 7, casing 61 is provided on its opposed long sides with brackets 84 having notches 85. Plate 16 is provided at two opposite corners thereof with sheared and bent portions to provide lugs or fingers 86 and 81 which are y offset downwardly from the plane of said plate. 7

pea

By initially tilting plate 'i6 lugs t6 and 8l may be inserted through notches 85 to aiiord a proper support for one end of the plate upon movement of the latter to 'its normal position. Rigidly at tached to the bottom wall of casing @il and underlying plate i6 adjacent to the other end of the latter is a hollow internally threaded member 88, a screw 89 (Figs. 5 and 7) penetrating an opening in plate it and taking into threaded member 88 to rigidly attach said plate 'I6 in assembled relation to, `but spaced upwardly from the bottom wall of, the casing Eil. A lock Wash er 90 is preferably interposed between the head of screw 89 and plate li?.

A neutral cr grounded bus member @i (Fig. 7) is secured to bosses 92 and 93 upon the bottom wall of casing till, as by means of screws or bolts SM and 65. Bus member 9| has a plate 96 attached thereto, as by means of rivets 6l, and plate 96 carries four wiring terminal screws Q8, each associated with one oi the branch circuits; the other wiring terminal screw o each branch circuit being shown at 3l (Figs. l and 10). Attached to bus member 9| at the opposite end thereof are three terminals or wiring' clamping devices 4I, 42 of the character aforedescribed, the same being carried by relatively short bus members 99, and |0I, as illustrated. Plate 'I6 (Fig. '7) is cut away as shown at I02 to provide access to the terminals last mentioned, and at |03 to provide access to terminal screws 98.

An arrangement of circuits to be controlled by the present device is illustrated diagrammatically in Fig. 10, wherein lines L1, L2 and L3 represent the source of current supply, and I1, I2 and I3 represent the lines leading to an electric range or similar translating device. Assuming .on positioning of the main and range fuse plugs, with the main and range fuses M and R respectively carried thereby, circuit may be traced from line L1, by bus 38 Athrough one of the main fuses M to bus 24, bus 34, and bus 21 through one of the range fuses R, and to line I1; and from line L3 by bus 38 through the other main fuse M, by bus 25, bus 28 and bus 26 through the other range fuse R, and to line I3; the neutral lines L2, I2 being jointly connected to the neutral or grounded bus member 8| aforedescribed.

In Fig. 10, the numerals |04. |05, |06 and |01 `designate branch lighting circuits or the like; circuits |04 and |01 being electrically connected through their respective branch circuit fuses and one of the main fuses M with line L1, and circuits and |06 being electrically connected through their respective branch`circuit fuses and the other main fuse M with line L3, and each of said branch lighting circuits being electrically connected with neutral bus member 9| and line L2. Numerals |08 and |09 designate bus leads electrically connected respectively with lines L1 and L3 through the respective main fuses. Thus if the main fuses M are of 60 ampere capacity, and the range fuses R are of 30 ampere capacity, the bus leads may be utilized to provide a tap up to 60 amperes capacity, with solderless terminal devices 4I, 42 (Fig. 1), for serving either a water heater or an extra distribution fuse circuit panel, located remote from the combination entrance (or main) and range switch device disclosed herein.

As shown in Figs. 3 and 4 the fuse carrying plug 46 (and also the fuse carrying plug 58 of Figs. 6 and 9) is provided with sets of openings .or passages ||0, I|I and |I2, II3 to provide for insertion of wire ends or rods into engagement v that shown at till (llg. 5).

with the respective fuse holding clips ci each pair, whereby the range and main fuses may be tested without requiring removal thereof from circuit. The block 29 (Fig. i) carrying the branch. circuit fuses isprovidecl with iour grooves or slots itt to provide for testing ci the branch :fuses without removal thereof from their respective circuits, the terminals 36 or screws Ell being utilized for contact by one of the testing wires or rods when testing the branch circuit fuses.

It branch circuit fuses are not required or desired, the block 2Q may be omitted, and relatively shorter bus members may be substituted for those shown at 2li, Effi, 2t and 2l in Fig. 2, thus permitting use ci a casing substantially shorter than Casing @l be provided with any desired number or form of knock-outs in the bottom, side and end walls thereof, several knock-outs i iii oi well known form being shown at l l5 in Fig. '7.

Each plug member 46 and 58 is provided in its upper surface with a recess 4S (Figs. 3 and 5) to accommodate spring 66, when compressed, and nger grip member t4 in a relation substantially iiush with said upper surface (see the right hand side of Fig. 6)'. Recess 46a also facilitates insertion of the finger or ngers between member 64 and the upper surface of the plug member, as best illustrated in Fig; 5.

What I claim as new and desire to secure by Letters Patent is:

1. In a fuse carrying switch plug, in combination, a molded insulating plug member having a centrally located opening of polygonal cross section formed therein, a metal member of corresponding cross sectional contour penetrating said opening and slidable with respect thereto, said metal member having an enlargement at its lower end to limit the degree of upward movement thereof, said metal member having a finger grip member rigidly and non-rotatably attached to ,the upper end thereof, and a coiled compression spring interposed between the upper surface of Asaid insulating member and said finger grip member to normally project the latter to its upper extreme position, said spring permitting depres sion of said metal member and said nger lgrip member upon closure of a suitable cover member associated therewith.

2. In a fuse carrying switch plug, in combination, a molded insulating plug member having a centrally located opening of polygonal cross section'formed therein, a metal member of corresponding cross sectional contour penetrating said opening and slidable with respect thereto, said metal member having `an enlargement at its lower end to limit the degree of upward movement thereof, said metal member having a iinger grip member rigidly and non-rotatably attached to the upper end thereof, a coiled compression spring interposed between the upper surface of said insulating member and said finger grip member to normally project the latter to its upper eX- treme position, said spring permitting depression of said metal member and said linger grip member upon closure of a suitable cover member associated therewith, and said insulating member having a recess to accommodate said spring when compressed and said finger grip member in a relation substantially flush with the upper surface of said insulating member.

3. In a fuse carrying switch plug, in combination, a molded insulating plug member of substantially rectangular contour, said plug member having a centrally located passage of square crossv section formed therein, a metal rod of square cross section located Within said passage in slidable but nonrotatable relationship thereto, said rod having a head formed at its lower end to limit upward movement thereof, said rod having a reduced portion of rectangular cross section at the upper end thereof, a fiat punched sheet metal finger grip member having `a central opening to fit onto the reduced portion of said rod in non-rotatable relationship thereto and in a plane parallel to the upper surface of said plug member, said reduced .portion having its outer end upset over said finger grip member to rigidly attach the latter to said rod, said plug member having an upwardly flared recess formed in the upper surface thereof to accommodate said nnger grip, member in a relationship substanvtially flush with said upper surface, and a coiled compression spring interposed between the bottom wall of said recess and the lower surface of said finger grip member to normally bias the latter to its upper extreme position.

4. In a fuse plug switching device, in combination, a metal casing having a bottom wall and pairs of side and end Walls, brackets secured to the respective side walls and alined with each other in spaced relation to said bottom wall, said brackets having notches formed therein, a sheet metal plate having offset portions at one end thereof respectively insertable into said notches upon tilting of said plate for interlocking engagement with said brackets, an internally threaded hollow metal member rigidly secured to the bottom wall of said casing and underlying the other end of said plate, a bolt penetrating said plate and having threaded engagement with said hollow metal member to rigidly secure said plate in position, a one-piece molded insulating base superimposed upon said plate and rigidly but removably attached thereto, saidbase having a recess opening to the upper surface thereof, a fuse carrying plug member insertable into said recess in either an on or an off position with respect thereto, the fuse carrying elements of said plug member being concealed in each of said positions, and said base and said plate being insertable into or removable from said casing as a unit.

5. In a main and range fuse plug switching device, in combination, a metal casing having a bottom wall and pairs of Side and' end Walls, brackets secured to the respective side walls and alined with each other in spaced relation to said bottom wall, said brackets having notches formed therein, a sheet metal plate having offset portions at one end thereof respectively insertable into said notches upon tilting of said plate for interlocking engagement with said brackets, an internally threaded hollow metal member rigidly secured to the bottom Wall of said casing and underlying the other end of said plate, a bolt penetrating said plate and having threaded engagement with said hollow metal member to rigidly secure said plate in position, a one-piece insmating base member superimposed upon said plate and rigidly but removably attached thereto, said base member having a pair of rectangular recesses formed therein and opening to the upper surface thereof, a main fuse carrying plug and a range fuse carrying plug respectively insertable into said recesses in an on or an off position, the fuse carrying elements of said plugs being concealed in each of said positions, one of said recesses being so formed with respect to nsaid range fuse carrying plug as to insure against on positioning of the latter Within the former, a plurality of Wiring terminal members carried by said insulating base member, a cover member rigidly and normally immovably attached to said casing in a relation to provide for concealment of said wiring terminal members While providing for exposure of said recesses, and an auxiliary cover member hinged to said iirst mentioned cover member to provide for concealment of said recesses, said auxiliary cover member being formed to accommodate said main and range fuse plugs in both the on and off positions of the latter.

6. In a device oi the character described, in combination, a metal casing having bottom, side and end walls, a dat metal plate supported in upwardly spaced relation to said bottom wall, means comprising a single screw adapted upon release thereof to permit removal of said plate from said casing, a molded insulating base rigidly but removably attached to said plate, said base having a pair of substantially rectangular recesses formed therein and opening to the upper surface thereof, a main fuse carrying plug and a range fuse carrying plug insertable into the respective recessesin either an on or an o position the fuse carrying elements of said plugs being concealed in each of said positions, one of said recesses being so formed with respect to the range fuse carrying plug as to insure against insertion of the latter into an on position within the former, a second molded insulating base removably attached to said plate at one end of said base first mentioned, said second base havinga plurality of branch circuit fuse receiving recesses formed therein and opening to the upper surface thereof, a cover member rigidly and nor- ^mally immovably attached to said casing and all of said recesses.

7. In a device of the character described, in combination, a metal casing having a bottom wall and pairs of side and end walls, a neutral bus member mechanically and electrically connected to the casing, said bus member having a plurality of terminal members associated therewith to provide for attachment of circuit wires thereto prior to insertion of an electrical device into said casing, an electrical device comprising a molded insulating'base having a plurality of terminal members associated therewith to provide for attachment of circuit Wires thereto prior to insertion of said base into said casing, said base having a flat sheet metal plate rigidly attached thereto, means within said casing for supporting said metal plate in upwardly spaced relation to said bottom wall, and said means including a single screw adapted to retain said plate in or release the same from assembled relation to said casing.

8. In a device of the character described, in combination, a metal casing having a bottom wall and pairs of side and end walls, a neutral bus member comprising a metal strip located within and supported by said casing adjacent to the bottom wall of the latter, said bus member having a plurality of terminal members associated therewith to provide for attachment of circuit wires thereto prior to -insertion of an electrical device into said casing, an electrical device comprising a molded insulating base having a plurality of terminal members associated therewith to providelv tot attachment of eiieuit Wires thereto prior to insertion oi" said losse into said casing, said lease laat/lne a metal plete rige 9. Ina devise of the character described, ink

combination, e, metal casing leaving bottom, side and end welle` a at metal plate supposte@ in upwanzly` speseol relation. to setti. bottom well, means comprising s, single screw edaptesl irjooizi release thereof 'to permit seinoivel of said plete from said casing, a molded insuleting lease rits idly but removably attasliesl to plate. sessi meeste base having a peir of substantially rectangular tecesses tesmed therein and opening to the upper sui-fece thereof a main fuse carrying plus and a range fuse carrying plug tnsertable into the respective recesses in either an. on or am off positiom the fuse carrying' elements ot said plugs items; concealed in eeoh of salol positions, one ot saisl sesesses being so formed with respect to the renee fuse carrying plug es to insure against insertion ot the latter into an on position within the former, e, cover member rigidly and normally lmmovably attached 'to said easing and having an opening to provide for exposure of the recesses eiorementiorxeol, enst on auxiliary @over member hinged to salti cover member ilrst mentionezi. adeptes when elesesl to overlle recesses.

RALPH it..

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