US1945819A

US1945819A - Electric switch of the enclosed type

Info

Publication number: US1945819A
Application number: US635184A
Authority: US
Inventors: Ralph A Millermaster
Original assignee: Cutler Hammer Inc
Current assignee: Cutler Hammer Inc
Priority date: 1932-09-28
Filing date: 1932-09-28
Publication date: 1934-02-06
Anticipated expiration: 1951-02-06

Description

6, 1934. R. A. MILLERMASTER ELECTRIC SWITCH OF THE ENCLOSED TYPE.

Filed Sept. 28, 1932 4 Sheets-Sheet 1 1934- R. A. MILLERMASTER ELECTRIC SWITCH OF THE ENCLOSED TYPE Filed Sept. 28, 1932 4 Sheets-Sheet 2 1934- R. A. MILLERMASTER ELECTRIC SWITCH OF THE ENCLOSED TYPE Filed Sept. 28, 1932 4 Sheets-Sheet 3 awwm dfim mammw @g Feb. 6, 1934. R. A. MILLERMASTER ELECTRIC SWITCH OF THE ENCLOSED TYPE 4 Sheets-Sheet 4 Filed Sept. 28, 1932 Patented Feb. 6, 1934 ELECTRIC SWITCH OF THE ENCLOSED TYPE Ralph A. Miller-master, Milwaukee, Wis., assignor to Cutler-Hammer, Inc.,

Milwaukee, Win, a

corporation of Delaware Application September 28, 1932 Serial No. 635,184

26 Claims.

This invention relates to improvements in electric switches of the enclosed type.

An object of the invention is to generally improve the construction and operation of such switches and to facilitate assembly of the various parts.

Another and more specific object is to provide a novel form of switch unit which may be readily secured Within or removed from the switch box or casing.

Another object is to provide such a unit wherein the operating handle is readily removable to permit assembly or removal of the unit with respect to the casing, to minimize the space requirements of the complete device during ship ment, and to insure against injury to the switch parts during shipment.

Another object is to provide a novel form of stationary and movable contacts and. an improved form of carrier or support for the latter.

Another object is to provide a novel form of metal frame for the switch unit.

Another object is to provide a switch unit the parts of which may be alternately arranged to provide a switch of the fused or non-fused type,-- the fuse supporting elements when employed being arranged at will to accommodate fuses-oi different size and capacity.

Another object is to provide a novel arrangement of elements afiording snap movement of the switch parts, in conjunction with interlocking means to normally insure against closing of the switch when the box cover is open and opening iof said cover when the switch is in. closed posi- 1011.

Other objects and advantages of the invention will hereinafter appear.

The accompanying drawings illustrate certain embodiments of the invention which will now be described, it being understood that the embodiments illustrated are susceptible of modification without departing from the scope of the appended claims.

In the drawings, Figure 1 is a top plan view of a fused safety switch constructed in accordance withmy invention,the casing cover being opened and one of the insulating supports for the fuse clips and stationary switch contacts being removed for purposes of illustration,--the 0 switch being shown in its open-circuit position.

Fig. 2 is a sectional view, on the line 2-2 of Fig. 1, with the box cover closed and the switch in closed-circuit position.

Fig. 3 is a sectional view, on the line 3--3 of Fi l.

Fig. 4. is a sectional view, on the line li of Fi 1.

Fig. 5 is a sectional view, on the line 5--5 of Fig. 1, looking in a direction opposite to that of Fig. 4.

Fig. 6 is a bottom plan view of one of the molded insulating supports for the fuse clips and stationary contacts,a pair of the latter being shown in position.

Fig. 7 is a perspective view of the switch handie and certain of the parts associated therewith.

Fig. 8 is a top plan view of a part of a switch unit like that shown in Fig. 1,-a modified frame element being employed to provide an extension support for certain of the fuse clips whereby fuses of relatively larger size and capacity may be accommodated.

Fig. 9 is a sectional view, on the broken line 9-9 of Fig. 3.

Fig. 10 is a top plan view of one of the insulating supporting members shown in Figs. 1 and 9,- a conducting bar or bus member being substituted for the fuse clips shown in Fig. 1.

Fig. 11 is a detail perspective view of one of the bridging contactors of the switch.

Fig. 12 is a perspective view of the L-shaped auxiliary frame member and the snap action and interlocking elements carried thereby.

Fig. 13 is a perspective view of the additional insulating block or extension illustrated in Figs. 8 and 9, and

Fig. 14 is a plan view of one of the punched plates of insulating material.

Referring to the drawings, the numeral 15 designates a metal box or casing having end walls so 15*, 15

side walls

15, 15 and a bottom wall 15 the front of said box being open, and the same being provided with an openable cover 15 which is preferably hinged by means of bent lugs 15 15 formed integrally with the side wall 15 and t5 adapted to penetrate corresponding openings formed in the flange of said cover 15 Spot welded or otherwise rigidly secured to side wall 15 is an upstanding resilient catch or lug 16 which acts in the usual manner through its sheared and offset portion 16 to releasably retain cover 15 in closed position. Lug 16 is also provided'with the usual opening 16* to accommodate the hasp of a padlock whereby the cover may be locked in closed position. Certain of the casing walls are provided with knockouts of well-known form to accommodate the circuit wires (not shown). The bottom wall 15 is shown as provided with four knockouts of the character aforementioned. Said bottom wall is also provided 11c with reversely arranged pairs of key-hole slots 15 15 and 15 16 to facilitate attachment of the casing to a suitable support as by means of the usual screws or bolts.

The side wall 15 ofthe casing is provided with an opening 17 (Fig. 2) which is preferably of circular contour, said opening providing clearance for the punched and stamped sheet metal plate 18 upon outward projection of the latter during attachment of the switch unit within the casing, as hereinafter described. Riveted or otherwise rigidly attached to the outer surface of side wall 15 is a punched and stamped sheet metal member having an arcuate portion 19 adapted to protect the

lugs

18, 18 on plate 18 during shipment and/or preliminary handling of the device,-said member also having angularly extending pertions 19', 19 to be engaged by the handle member 20 to limit movement of the latter in opposite directions respectively, said portions having openings 19, l9 which respectively cooperate with the opening 20* (Fig. 7) in the handle member to receive the hasp of a padlock whereby the switch may be locked in open or closed position. Side wall 15 is also provided at spaced points with openings (not shown) to provide clearance for the shanks of

screws

21, 22 which take into tapped openings 23, 24 (Figs. 1 and 12) in the vertical portion 25 of an L-shaped auxiliary frame member, the horizontal portion of the latter being designated by the numeral 26. Said horizontal portion 26 is provided with tapped openings 26*, 26 to provide for attachment thereof to the main frame member in the manner hereinafter described. Said vertical portion 25 carries an interlocking device of the character described and claimed in the Dante Patent No. l,- '7,'711, dated May 10, 1932. Said device as shown comprises a bracket 27 riveted or otherwise rigidly secured to portion 25, said bracket having an offset or bend 27* to. provide a tubular bearing for the rod or plunger 27.

Plunger 27 is provided at its upper end with a lug 27,a coiled torsion spring 2'7 being interposed between bracket 27 and lug 27 to bias the same and plunger 2'7 upwardly and rotatably to the position thereof illustrated in full lines in Figs. 1 and 5. The lower edge of the bearing por-- tion 27* is notched as indicated at 27 and the lower end 2'7 of plunger 27 is bent laterally into vertical alinement and parallelism with lug 27,- said end 27 being adapted (in the full line position of the plunger as shown in Fig. 5) to seat in notch 27' to positively restrain the plunger against rotary movement.

Plunger 27 assumes this position only upon open-circuit positioning of the switch parts and simultaneous opening of the casing cover. When the casing cover is closed plunger 27 is automatically depressed to permit rotation of the bent end 27 thereof to the dotted line position illustrated in Fig. 5 upon actuation of the switch parts to closed-circuit position. Lug 27 is likewise moved to the dotted line position thereof shown in Fig. 5, wherein it engages the downwardly offset portion 15 (Fig. 2) of a lug attached to the cover 15*, whereby the latter is retained in closed position pending movement of the switch parts to open-circuit position.

The snap action elements carried by the vertlcal portion 25 of the auxiliary frame member. comprise essentially a. metal member 28 (preferably a casting) having a pair of cam portions 28' and 28 formed thereon, said member having a machined projection 28 adapted to bear within a circular opening 25* (Fig. 2) in the vertical portion 25 and in a relation substantially flush with the outer surface of said portion,-the shoulder at the inner end of said projection being adapted to rotatably bear against the inner 8 surface of portion 25. Member 28 is provided with a substantially cylindrical recess 28* which is open throughout its depth at one side to provide assembling clearance for the downwardly projecting inner end 28 of a coiled torsion 5 spring 28 and to provide for rotary movement of member 28 throughout the range defined by edges 28 and 28' (Fig. 12) when the end 28 is temporarily held in fixed position, as hereinafter described. Recess 28 is also open for a portion 9 of its depth at the opposite side thereof to provide assembling clearance for the downwardly projecting outer end 28 of the spring and to provide for rotary movement of member 2153 in the reverse direction throughout the range defined 8 by edges 28 28 when the end 28 is temporarily held in fixed position; it being understood that the aforementioned edges 28 28 28 and 128 are integral with the member 28.

As shown the spring 28 is located between the wall of recess 23* and a cylindrical member 29. the closed inner end 29 of which is rigidly attached to member 28 and to plate 18 by means of rivets 29 The aforedescribed parts are thus held in bearing relationship to the vertical po1rtion 28 of the auxiliary frame men'iber. The member 29 is provided at its outer end with a flange 29 to retain spring 28 in assembled position.

The main frame comprises essentially a pair of punched and stamped sheet metal end members 3i) and 31, which as shown are of identical form which form is best illustrated in Fig. 4. However, since the end member 31 is not required to carry pawls corresponding to the

pawls

44 and 45 on member 30, the portion of member 31 between lugs 31 31 (Fig. 3) might be considerably reduced in height, so long as a proper bearing for the shaft 42 is provided.

Members

30 and 31 are respectively provided l2i with bottom flanges 30", 31 and inwardly bent lugs at opposite upper ends thereof, as shown in dotted lines at 30 30 in Fig. 1 and at Bl. and 31,in Fig. 3. Adapted to span the longitudinally alined lugs of

members

30 and 31 are a pair of flat punched

sheet metal members

32 and 22,- the latter being spot-welded or otherwise rigidly attached to said lugs to provide a composite main frame of substantially inverted U -shape.

I provide a sub-assembly for the movable eontaetors and carrier elements of the switcli,--tlie same comprising essentially. a seli-sustaining tubular insulating member 34 of square cross section. Slidable onto tube 34 in proper sequence are a plurality of molded insulating and

spacing members

35, 36, 37 and 38 oi cylindrical iorm,-the same having square passages to provide for positive engagement thereof with tube 34.

End members

35 and 38 are of like form and

intermediate members

38 and 37 are of like form,--the abutting ends of the respective members being recessed as shown to accommodate the connecting portions 39 and portions of the parallel arms 39 39 of the several bridging eontactors 39. The arms of contactors 3e are provided with alined

square openings

39, 39 whereby the contactors may be slid onto tube 34: for driving engagement by the latter. I prefer to interpose between tube 34 and the walls of openings 39 39' the pairs of angularly bent sheet 150 metal members 39 39 (as best illustrated in Fig. 8). In this manner excessive. cutting or wear of tube 34 by contactors 39 is avoided. The arms 39*, 39 of the contactors are provided at their upper end portions with arcuate side edges, said edges being swaged or beveled to provide knifeedges 39 39 for cooperative engagement with the stationary contacts of the switch. Metal washers 40 and 41 (Fig. 2) are positioned inrecesses in

members

38 and 35 at opposite ends of tube 34,-said washers providing bearing surfaces for engagement with the inner edges of annular inturned bearing flanges 30 31 formed on

end members

30 and 31. The sub-assembly thus described is insertableas a unit between the

end members

30 and 31, whereupon the square shaft 42 may be slid from right to left through bearing 30 tube 34 and bearing 31 to provide a rotatable driving support for said parts.

As shown the left-hand square end of shaft 42 fits rotatably within the bearing provided by flange 31 of member 31, the projecting end 42 of said shaft being preferably of reduced cylindrical cross section to accommodate the metal washer 42 ,--a cotter pin 42 or the like being employed to restrain the shaft against endwise movement toward the right (Fig. 2). The righthand end portion of shaft 42 may be left of square cross section, but I prefer to machine the same to slightly reduced cylindrical cross section to accommodate a metal collar or bushing 42 to provide an annular bearing surface thereof for engagement within flange 30 The extreme righthand end 42 of shaft 42 is further reduced by machining or otherwise to provide a portion of rectangular or other polygonal cross section to accommodate the correspondingly shaped opening in the punched and stamped sheet metal member 43, the projecting end of portion 42 being upset as shown at 42 to rigidly unite member 43 with shaft 42.

End member 30 of the main frame (Fig. 4) is provided with an arcuate slot 30 which provides clearance for and limits opposite movements of an integral lug 43 bent inwardly from member 43.

Member 43 is also provided at opposite sides thereof with teeth or

shoulders

48 and 43 which are alternately engaged by the respective pawls or

dogs

44 and 45 which are pivoted at 44 45 to member 30. Member 30 is punched out as shown at 30 and 30 to provide an abutment for one end and clearance for the body portion of .the respective compression springs 46 and 47,--the other ends of said springs being adapted to engage abutments formed adjacent to the free ends of

pawls

44 and 45 whereby the latter are biased toward member 43. Formed integrally with member 43 and extending outwardly at a right angle thereto is a relatively long lug 43 the op" posite edges of which are adapted to selectively engage the

ends

28 and 28 of spring 28 to temporarily hold the respective ends in fixed position to tension spring 28 whereby a snap movement of the switch contactors to closedcircuit or open-circuit position is insured.

As shown in Fig. 4 the

pawls

44 and 45 are respectively provided with

lugs

44 and 45 ex tending from the outer edges thereof at right angles thereto, said lugs being alternately engageable by the cam portion 28 of member 28 to withdraw the pawls 44 and 45from engagement with

teeth

43 and 43 upon movement of actuating handle 20 toward switch closing or switch opening positions selectively.

Thus as indicated in Figs. 1 and 4 the switch parts are in open-circuit position-the pawl 44 being engaged with tooth 43 to temporarily hold the contactors against movement. On the other hand upon movement of the operating handle 20 in a direction to effect closure of the switch the spring end 28 (Figs. 5 and 12) will be carried in a counterclockwise direction due to engagement therewith of the edge 21 while the spring end 28 is engaged with lug 43 to effect the required storage of energy within spring 28 After a. predetermined degree of movement of handle 20 in such direction the cam portion 28 will engage and release pawl 44 thus allowing the contactors to snap into engagement with the stationary contacts of the switch. In the meantime cam portion 28 will have disengaged pawl 45 to permit the latter to interlock with tooth 48 upon fully closed positioning of the switch contacts. Reverse movement of handle 20 will then cause clockwise movement of spring end 28 through engagement of the edge 28 with the latter, while spring end 28 is held fixed by lug 48 to store energy in spring 28 pending disengagement of pawl 45 from tooth 43 (as illustrated in Fig. 4) to permit snap movement of the switch to open-circuit position.

fhe switches herein illustrated are of the three-pole double-break type, but it is to be understood that switches having a greater or lesser number of poles may be constructed in accordance with my invention. 1 have provided novel insulating and supporting means for the stationary contacts, line and load terminals and fuse clips (when a fused switch mechanism is desired). Said means as shown comprises three molded insulating members 48 of identical form,

ill)

each of which is provided in the bottom surface thereof with a pair of recesses 48*, 48 within which are respectively located the pair of

resilient clip contacts

48, 48 the forward edges of which are angled or flared, as best illustrated in Figs. 2 and 3 to facilitate engagement of the bridging contactors 39 therewith. Contact 48 is provided with a rearwardly extending integral lug (Fig. 1) which overlies a ledge 48 formed on member 48, a countersunk passage 48 (Fig. 6) being adapted to register with a tapped opening in .said lug,the shank of bolt 48 cooperating with said tapped opening to assist in retaining contact 48 in assembled relation to member 48. A nut 48 is threaded onto the exposed shank of bolt 48 to provide one of the line terminals of the switch. Contact 48 is provided with a seclies a ledge 48 ,--said lug being tapped to receive the shank of bolt 48 which extends upwardly through base 48. Contact 48 is also provided with a tapped opening to receive the shank of bolt 48 which extends downwardly through member 48, the head of bolt 48 being in clamp ing engagement with the connecting portion of a U-shaped fuse clip 48 of known form whereby the latter is retained in fixed position.

A second fuse clip 48 is shown in Figs. 1 and 3 as being riveted or otherwise rigidly secured to the inner end of a bus member 48 ,-the latter having a tapped opening to receive the shank of bolt 48* whereby said bus member and clip 48 are held in position. A nut 48 is threaded onto theexposed shank of bolt 48 to provide one of theload terminals of the switch. If it is desired to employ fuses of somewhat greater size and capacity, the clip 48 may be omitted and a clip similar thereto may be positioned directly over the passage within which bolt 48 is located, a not being waxed into the countersunk portion of said passage to receive a clamping bolt extending downwardly through the fuse clip, and a bus member similar to that shown at 48 being clamped in position by the bolt head and having means for attaching one of the load wires thereto.

The bottom surface of member 48 is provided with grooves 48 and til to provide clearance for the

arms

39 and 39 of the contactor, said grooves also acting to snuil any arcs formed in-- cident to separation of the switch contacts. Each member 48 is also provided on its lower surface with intermediate and end

barriers

48 and 48 to properly insulate the stationary and movable'contacts associated therewith. Each member 48 is provided with a pair of counter" sunk openings to accommodate bolts 48 48 the shanks of which respectively take into tapped openings in

members

32 and 33 whereby the member 48 is rigidly secured in assembled position. The upper surface of each member 48 is provided at one side thereof with an integral insulating barrier 48 extending throughout the major portion of the length thereof,--a relatively shorter integral insulating barrier 48 being also provided at one end of each. member 48 to properly insulate the lug portion of switch contacts 48 and the line wire terminals on the adjoining members 48.

After the sub-assembly including contaotors 39, shaft 42 and the associated insulating and spacing members have been mounted between the end members of the main frame as aforedescribed, the horizontal portion 26 of the auxiliary frame member is slid from right to left (Fig. 2) through

openings

30 and 31 provided in the

end members

30 and 31, the parts being so positioned as to provide for engagement of spring ends 28 and 28 with opposite side edges of lug 43 (see Fig. 5). The

bottom flanges

30 and 31 of said end members are provided with chamfered openings registering with the tapped

openings

26, 26 formed in horizontal portion 26, bevel-headed screws 49 and so being driven upwardly through said openings to retain the main and auxiliary frame members in assembled relation.

As shown in Fig. 2 insulating member 35 is provided with a cylindrical end 35 of reduced cross section, and members 36 and 3'? are respec tively provided with annular grooves 36*, 37 three punched plates 35' 36 and 37 of insulating material being positioned as shown to more cfiectively insulate the respective sections of the switch mechanism. Said plates are all of the form shown in Fig. 14, the same preferably being composed of fiber impregnated with a phenolformaldehyde condensation product such as bakelite; As shown in Fig. 3 the lower ends of said plates are adapted to rest upon the horizontal portion 26 of the auxiliary frame member,--the

metal members

32, 33 and lugs 31 31 having notches on the inner edges thereof to accommodate the vertical edges of said plates to assist in retaining the latter in po"ition. Thereafter the insulating members are positioned upon the

metal members

32, 33 and attached thereto by bolts 48', 48* as aforedescribed.

With the main and auxiliary frame members and their associated parts thus assembled the resulting unit may be inserted into the switch casing 15 in a direction at right angles to the bottom wall 15 thereof. The end member 31 (see Fig. 9) is provided with inwardly extending slots 31 31 whereby the opposite ends of the bottom flange 31 thereof may be readily slid into interlocking engagement with the

triangular pockets

15, 15 formed in the bottom wall l5 by a slitting and stamping operation. Upon sliding of the switch unit toward the right (Fig. 1) the vertical portion 25 of the auxiliary frame member is adapted to abut the side wall 15 of the casing whereupon the

screws

21, 22 may be threaded into the tapped openings .23, 24 to rigidly secure the unit in position within the casing.

When it is desired to attach the handle 2b (Fig. 7) it is only necessary to insert the forked end 20* thereof in interlocking engagement with the walls of the notches formed opposite of lug 18 and thereafter insert screw rac through clearance opening :30 in the handle and into tapped opening 18 in lug lib to rigidly clamp the handle in position; a lock washer 20 belts: 7

preferably employed to prevent accidental loosening of said screw. This arrangement is in general similar to that described and claimed in Dante Patent No. 1,834,939, dater December ll.

been omitted and a conductor or bus member 51 employed to provide a switch of the nonduscd type.

The device illustrated in Figs. 8 and 9 is in I many respects identical with that first described and corresponding parts have been given like numerals of reference. The device of ii and b is adapted to provide tor use of fuses of relatively large size and capacity, and for this purpose I substitute for the metal member 32 of Fig. l. a relatively wider metal member 52, the

same having downwardly extending flanges .52, 52 to provide a relatively strong bracket, and to permit spot-welding thereof not only to inwardly bent lugs 30 31 but also to the vertical portion of the end members 30 and Bi. bracket 52 as by means of

bolts

53, 54% taking into tapped openings in the :i'orrner is a molded insulating member 55, said member having rela tively large size fuse clips 55 attached thereto in alinement with the fuse clips of corresponding 1 size attached to the respective insulating mcmbore 48; load terminals 55 being also provided. Member 55 is provided with integral insulating

barriers

55, 55 and 55 arranged as illustrated.

Fig. 13 is a detail perspective view of insulating member 55.

The device illustrated in Fig. l a rated capacity of 30 amperes 250 volts; and said device as modified to accommodate the relatively larger fuse elements as aforedescribed has rated 4 capacity of 60 amperes 250 volts. The device illustrated in Figs. 8 and 9, on the other hand, has a rated capacity of 3b amperes 60o volts,- assuming use of proper fuses in each instance.

From the foregoing it will be apparent that I have provided-a combination of switch and use elements of simple and rugged construction and adaptable for rearrangement with a minimum number of additional parts to provide fused or In Fig. 10 I have shown modified arrangc- Attached to 1i iii non-fused switch devices having widely different electrical characteristics.

In Fig. 1 I have shown a grounding-wire ter== minal 56 attached to end wall 15 as by means of bolt 56 and nut 56 In Fig. 1 I have also illustrated in dotted lines at 57 a plate of fiber or other insulating material,-the same being attached as by means of screw 57 (shown in dotted lines) to a bracket carried by end wall 15 of the casing.

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

l. In an electric switch, in combination, a rotatable shaft of substantially rectangular cross section, a tubular insulating member of similar cross section surrounding said shaft, a bridging contactor comprising a punched sheet metal member bent to substantially U-shape to provide a pair of spaced parallel contact arms integrally connected with each other, said arms having alined rectangular openings formed therein to accommodate said insulating member whereby a positive driving connection between said shaftand said contactor is provided, a pair of molded insulating members slidable onto said shaft from opposite sides of said contactor, the abutting ends of said last-mentioned members being recessed to accommodate said arms and the integral con necting portion, said last-mentioned members being positively engaged with said tubular member, and associated means for insuring against substantial endwise displacement of said last-mentioned members and said other, said last-mentioned members being adapted to permit a slight degree of displacement of said contactor endwise of said shaft.

2. In a device of the character described, in combination, a frame comprising a pair of punched and stamped sheet metal end members, each of said members comprising an upright portion, a bottom flange bent at right angles to said upright portion, and lugs bent at right angles to said upright portion at opposite sides of the upper end of the latter, said end members being arranged in parallel spaced relation to each other, and a pair of punched sheet metal strips arranged fiatwise in parallel spaced relation, each strip being rigidly attached to one lug of each end member, whereby all of said frame elements are maintained in assembled relation.

3. In a device of the character described, in combination, a frame comprising a pair of punched and stamped sheet metal end members, each of said members comprising an upright portion, a bottom flange bent at right angles to said upright portion, and lugs bent at right angles to said upright portion at opposite sides of the upper end of the latter, said end members being ar ranged in parallel spaced relation to each other, a pair of punched sheet metal strips arranged fiatwise in parallel spaced relation, each strip being rigidly attached to one lug of each end member, whereby all of said frame elements are maintained is assembled relation, and a plurality of molded insulating members of identical form spanning said metal strips and secured thereto for support thereby, each of said insulating members having a plurality of stationary switch contacts and a plurality of wiring terminal elements attached thereto.

l. In a device of the character described, in combination, a built-up frame comprising punched sheet metal end members and a pair of punched sheet metal strips adapted to span said end members and attached thereto to maintain shaft relatively to each the same in predetermined spaced relation, a plurality of molded insulating members of identical form adapted to span said metal strips and re movably attached thereto for support thereby,

each of said insulating members having a pair 80 of fuse clips removably attached thereto and exposed on the upper surface thereof, each of said insulating members also having a pair of recesses formed in the lower surface thereof and stationary switch contacts removably secured with- $5 in the respective recesses, an insulating tube of rectangular cross section, a plurality of bridging contactors each bent to provide a pair of parallel contact arms, said arms having alined rectangu lar openings to provide for slidable interlocking an engagement thereof with said tube, a plurality of molded insulating and spacing elements interposed between the respective contactors, said elements also being interlocked with said tube, said tube, contactors and spacing elements being in== sertable as a unit between the end members of said frame, said end members having alined bear ing openings formed therein, and a metal shaft of rectangular cross section insertable through. said bearing openings and said tube, said shaft Mm having means to prevent endwise displacement thereof relatively to said frame when the afore= mentioned parts are in assembled relation.

5. In an electric snap switch of the safety type, in combination, a built-41p frame comprising a m5 pair of punched sheet metal end members, each of said members having a flange at the lower end thereof and end and intermediate slots the lower walls of which are respectively defined by said flange, each of said members having a pair of 1 opposite end lugs bent inwardly from theupper edge thereof, a pair of punched metal strips hav ing the ends thereof superimposed upon said lugs and welded thereto to retain said parts in assem= bled relation, an auxiliary frame member of sub stantially L-shape, the horizontal portion of said auxiliary member being insertable within the in termediate slots in said end members and detach ably secured to the flanges on each of the latter, the vertical portion of said auxiliary member having a snap action mechanism secured thereto, a shaft of polygonal cross section rotatably sup= ported by said end members, said snap action mechanism having a driving connection with said shaft, a plurality of iJ-shaped bridging contactors carried by said shaft and insulated therefrom, and a plurality of molded insulating members of identical form attached to said metal strips, each of said insulating members having a pair. of stat-=- tionary contacts attached thereto for cooperative engagement by said bridging contactors, each of said insulating members also having fuse supporting means attached thereto and exposed on the upper surface thereof, said insulating members with their attached elements being remov= able individumly at will independently of the other parts of the switch.

6. In an electric snap switch of the safety type, in combination, a built-up frame comprising a pair of punched sheet metal end members, each of said members having a flange at the lower end thereof and end and intermediate slots the lower walls of which are respectively defined by said flange, each of said members having a pair of opposite end lugs bent inwardly from the upper M5 edge thereof, av pair of punched metal strips having the ends thereof superimposed upon said lugs and attached thereto to retain said parts in assembled relation, an auxiliary frame member of substantially L-shape, the horizontal portion 150 did of said auxiliary member being insertable within the intermediate slots in said and members and detachably secured to the flanges on each of the latter, the vertical portion of said auxiliary member having a snap action mechanism secured thereto, a shaft of polygonal cross section rotatably supported by said end members, said snap action mechanism having a driving connection with said shaft, a plurality of U-shaped bridging contactors carried by said shaft and insulated therefrom, a plurality of molded insulating members of identical form attached to said metal strips, each of said insulating members having a pair of stationary contacts attached thereto for cooperative engagement by said bridging con tactors, each of said insulating members also having fuse supporting means attached thereto and exposed on the upper surface thereof, a boxlike sheet metal casing having an openable cover, the bottom wall of said casing having slits formed therein adjacent to one side wall thereof and di vergent with respect to the latter, the metal at the remote sides of said slits being offset upwardly to provide a pair of triangular pockets, the end portions of the flange on one of said end members being slidable into said pockets whereby the frame is interlocked at one end with said bottom wall, the other side wall of said casing having an opening to accommodate a part of said snap action mechanism, a switch operating handle, and means for removably attaching said handle to said last mentioned part exteriorly of said casing.

7. In a fused switch of the snap action type, in combination, a built-up frame comprising punched sheet metal and members and a pair of punched sheet metal strips adapted to span said end members and attached thereto to maintain the same in predetermined spaced relation, a plurality of molded insulating members attached at opposite ends thereof to said metal strips, each of said insulating members having at least one fuse clip and a pair of stationary switch contacts attached thereto, a plurality of bridging contactors each comprising a pair of spaced parallel arms integrally connected with each other, said arms having alined openings of polygonal contour formed therein, an insulating tube adapted to fit within said openings for driving engagement with said contactors, a plurality of molded insulating and spacing members interposed between said contactors, said spacing members also being interlooked with said tube, a metal shaft penetrating said insulating tube and having driving engagement with the latter, said end members having openings within which said shaft is adapted to bear, one end of said shaft having a crank mem-- ber rigidly attached thereto, said end members having alined slots formed therein adjacent to the lower ends thereof, an auxiliary sheet metal frame member of substantially L-shape, the horizontal portion of said auxiliary member being adapted to fit within the slots in said end members and being attached to the latter for support thereby, snap action mechanism carried by the vertical portion of said auxiliary member, said mechanism having cooperative engagement with said crank member, a box-like metal casing the bottom wall of which is provided with integral lugs for cooperative interlocking engagement by one of the end members of said frame, means on the vertical portion of said auxiliary member to provide for attachment thereof to another wall of said box, said last-mentioned wall having an opening formed therein, and said snap action Illtchanism having a portion thereof projecting tion to retain all of said parts through said opening to provide for removable attachment thereto of a handle of suitable form.

8. In combination, an oscillatable bridging contactor for enclosed safety switches comprising a punched sheet metal member bent to substan- 'ilally U-shape to provide a pair of spaced parallel contact arms integrally connected with each other at the lower ends thereof, said contact arms having alined rectangular openings formed therein, the portion of said member which connects said contact arms being adapted to form one wall of each of said openings, the upper end portions of said contact arms having side edge extensions of arcuate contour, said side edge extensions being beveled to facilitate engagement thereof with stationary contacts of suitable form, and a shaft of rectangular cross section pcnetrating said alined openings, said shaft forming the axis of oscillation of said contactor.

9. In an electric snap switch, in combination, a punched sheet metal frame member having portions thereof bent to extend at right angles relatively to each other, one of said portions having a hearing opening-formed therein, snap actuating means arranged on one side of said lastmentioned portion, said means including a men1- her having a shoulder adapted to bear against one face of said last-mentioned portic'n and a cylindrical projection adapted to bear within said opening in a relation substantially flush with the other face of said portion, a punched and stamped sheet metal plate adapted to overlie said opening, said plate being rigidly attached to said prcjecin assembled relaticnship to each other, said plate having a pair of spaced flanges formed thereon, a handle having interlocking engagement with one of said and means for detachably securing said handle to the other flange whereby said snap actuating means may be'operated.

10. In an electric switch, in combination, a metal frame member having a bearing open-- 'ing formed therein, snap action means positioned on one side'oi said member and including a cylindrical projection adapted to bear with--- I;

in said opening in a relation substantially flush with the other side of said member, a punched and stamped sheet metal plate adapted to over-- lie said opening, said plate being riveted to said projection to rigidly and permanently secure said parts in assembled relation, said plate having a pair of spaced lugs formed integrally therewith, one of said lugs extending upwardly at right an gles to said plate and having alined notches formed in the opposite edges thereof, a handle comprising a punched sheet metal member end of "which is provided with projections adapted for cooperative engagement with the walls of said notches, the other of said lugs extending upwardly and then outwardly with respect to said plate, said last-mentioned lug having a tapped opening formed therein, and a screw the shank of which penetrates said sheet metal member r do and engages said tapped opening to rigidly but releasably secure said handle to said plate.

11. In an electric switch, in combination, a self-sustaining insulating tube of square cross section, a bridging contactor consisting of a punched sheet metal member bent ilatwise at two points to provide a flat connecting portion and two parallel contact arms, said arms having alined square openings formed therein whereby the same may be freely slid onto said tube, a sheet metal member interposed between certain of the walls of said openings and said tube to minimize wear upon the latter, a pair of molded insulating members of substantially cylindrical form freely slidable onto said tube on opposite sides of said contactor, the ends of said insulating members being adapted for abutting engagement with each other and said ends having recesses to complementally accommodate the connecting portion and the arms of said. contactor, and means for preventing movement of said insulating members endwise of said tube, said means including a pairof frame members between which the aforementioned parts may be inserted as a unit.

12.1n an electric switch, in combination, a metal shaft of polygonal form in cross section, a preformed tube of insulating material of the phenol-formaldehyde condensation type, said tube being of the aforementioned form in cross section whereby said shaft may be slid thereinto for driving engagement therewith, a plural ty of bridging contactors each of which comprises a punched sheet metal member bent flatwise at two points to provide a flat base portion and two parallel contact arms, said arms having alined polygonal openings formed therein whereby the same are slidable onto said tube for interlocking engagement with the latter, a plurality of molded insulating elements of cylindrical form, said elements having passages of polygonal form to provide for interlocking engagement thereof with said tube, said elements being arranged in pairs on opposite sides of the respective con tactors and the same having end recesses to ac commodate portions of the respective arms and the connecting portions formed integrally with the latter, and means for restraining said elements against movement longitudinally of sad tube, the aforementioned end recesses being sufficiently large to permit a slight degree of movement of said contactors longitudinally of said shaft to provide for self-alinement of said contactors with respect to the cooperating stationary contacts of the switch.

13. In an electric switch, in combination, a preformed, self-sustaining insulat ng tube of square cross section, a plurality of bridging contactors each consisting of a punched sheet metal member bent flatwise at two points to provide a flat connecting portion and two parallel contact arms, said arms having alined square openings formed therein whereby the respective contactors may be freely slid onto said tube, a pair of punched and stamped sheet metal members interposed between each of the respective contactors and said tube, sa d metal members being adapted jointly to substantially surround said tube to min mize wear upon the latter, a plurality of intermediate insulating members and a plurality of end insulating members, each of said insulating members being of substantially cylindrical form and each having a central passage to provide for slidable but non-rotatableengagement thereof with said tube, said insulating members being arranged in pairs on opposite sides of the respective contactors, the adja cent ends of each pair being complementally re- 4 cessed to accommodate the arms and connecting portion of the associated contactor, said pairs of recesses providing for a slight degree of movement of said contactors longitudinally of said tube to permit self-alining of the former with respect to the stationary contacts of the switch,

means for preventing movement of said insulat-.

ing members endwise of said tube, said means including a pair of frame members between ing spaced from and opening ,when said cover is open,

which all of the aforementioned parts may be readily inserted as a unit, said frame members having alined openings formed therein, and a metal shaft penetrating said last mentioned openings and said tube to provide a rotatable support for said contactors.

14. In an enclosed switch, in combination, a box-like sheet metal casing having an openable cover, the bottom wall of said casing having a pair of pockets formed thereon, said pockets being spaced from one side wall of the cas ng and opening toward the latter, the opposite side wall of said casing having a substantially circular opening formed therein, a snap switch mechanism freely insertable as a unit into said casing in a line at right angles to the bottom wall of said casing,

said mechanism including a frame member having flange portions adapted for interlocking ehgagement with the walls of said pockets upon bodily sliding movement of said unit toward the second mentioned side wall of saidcasing and a second frame member removably attachable to said second mentioned wall to retain said unit in fixed position, said mechanism also including a projection adapted to penetrate said wall opening,

I and a handle removably attachable to said pro- 'jection exteriorly of said casing to provide for operation of said switch mechanism.

15. In an enclosed switch, the combination with a box-like sheet metal casing having a hinged cover. the bottom wall of said-casing having a pair of pockets formed thereon, said pockets betoward one side wall of the casing, the opposite side wall of said casing havIng a substantially circular opening formed therein adjacent to the lower end thereof, of a combined fuse support and snap switch mechanism insertable as a unit into said casing in a line at right angles to the bottom wall of said casing said mechanism .ncluding a sheet metal frame member having bottom flange portions adapted for interlocking engagement with the walls of said pockets upon bodily movement of said unit laterally toward the sec ond mentioned side wall of said casing, said un't having an auxiliary frame part adapted for parallel abutment against said second mentioned sidewall and beingreadily attachable to the latter to retain said unit in fixed posit'on, a plurality of snap action elements carried by and rotatable with respect to said auxiliary frame part, one of said elements having parts extending through said wall opening and spaced slightly beyond the outer surface of said casing, and an operat ng handle including a lever formed of sheet metal, said lever being removably engaged with one of said last mentioned parts and having means for ready attachment thereof to the other of said parts whereby said switch mechanism may be operated.

16. In an enclosed switch, the combination with a box-like sheet metal cas ng having a hinged cover, the bottom wall of said casing having a pair of pockets formed thereon, said pockets being spaced from and opening toward oneside wall of the casing, the opposite side wall of said casing having a substantially circular opening formed therein adjacent to the lower end thereof, of a comb'ned fuse support and snap switch mechanism insertable as a unit into said casing in a line at right angles to the bottom wall of said casing when said cover is open, said mechanism including a sheet metal frame member having bottom flange portions adapted for interlocking engagement with the walls of said pockets upon bodily movement of said unit laterally toward the second mentioned side wall of said casing, said unit having an auxiliary frame part adapted for parallel abutment against said second mentioned side wall and being readily attachable to the lat: ter to retain said unit in fixed position, a plurality of snap action elements carried by and rotatable with respect to said auxiliary frame part, one of said elements having parts extending through said wall opening and spaced slightly beyond the outer surface of said casing, an operating handle including a lever formed of sheet metal, said lever being removably engaged with one of said last mentioned parts and having means for ready attachment thereof to the other of said parts whereby said switch mechanism may be operated, said switch mechanism including a plurality of molded insulating members of like form to be attached to the upper portion of the metal frame, said members each having fuse supporting and/ or wiring terminal elements attached to the upper surface thereof and a pair of stationary switch contacts attached to the lower surface thereof, a plurality of bridging contactors of substantially U -shape, means for supporting said contactorsfor oscillating movement into and out of engagement with said contacts, said means comprising a metal shaft with which said contactors are interlocked but from which the same are Jointly insulated, said shaft having bearing engagement with the metal frame and being fixed against endwise movement with respect thereto, and means providing a resilient interlocking connection between said shaft and the snap action elements carried by said auxiliary frame part.

1'7. In an enclosed safety switchv of the fused type, in combination, a box-like sheet metal casing having an openable cover, a sheet metal frame supported within said casing, said frame comprising a pair of end members and a pair of relatively narrow metal strips attached to said end members and forming the upper surface of said frame, a plurality of molded insulating members of like form attached to the upper surfaces of said metal strips, each of said insulating members having fuse supporting elements attached to the upper surface thereof and a pair of stationary switch contacts attached to the lower surface thereof, line and load terminal elements associated with certain of the switch contact and fuse supporting elements respectively, a plurality of oscillatable contactors of substantially U-form, each of said contactors being movable into and out of bridging engagement with one of said pairs of stationmy contacts, a shaft for effecting oscillating movement of said contactors jointly, means for insulating said contactors from said shaft, manually operable snap action mechanism, and means providing a driving connection between said mechanism and said shaft.

18. In an enclosed safety snap switch, in combination, a sheet metal frame comprising a member of inverted U-shape and a member of L-shape engaged with thebottom portion of said first mentioned member and attached thereto, a plurality of cooperative stationary and movable switch contacts supported by said U-shaped momher but insulated therefrom, and a snap action mechanism having parts thereof respectively carried by said U-shaped member and said L-shaped member and interposed therebetween, said mechanism having an operative connection with the movable contacts of the switch.

19. In an enclosed safety snap switch, in combination, a sheet metal frame comprising a member of inverted U-shape and a member of L-shape engaged with the bottom portion of said first mentioned member and attached thereto, a plurality of cooperative stationary and movable switch contacts supported by said U-shaped mem-- her but insulated therefrom, a snap action mechanism having parts thereof respectively carried by said U-shaped member and said L-shaped member and interposed therebetween. said mechanism having an operative connection with the movable contacts of the switch, one arm of said L-shaped member having an opening formed therein, said snap-action mechanism having a shouldered part adapted to bear within said opening, a punched and stamped sheet metal plate overlying said opening and rigidly attached to said last mentioned part to retain the same in assembled position, said plate having a pair oi lugs formed thereon, a handle member adapted for interlocking engagement with one of said lugs, and fastening means associated with the other lug and said handle to provide for ready attachment and detachment of said handle with respect to said plate.

20. In an enclosed safety snap switch of the fused type, in combination, a sheet metal frame of substantially inverted U--shape, said frame comprising a pair of parallel end members and a pair of sheet metal members spanning the upper edges of said end members and arranged in spaced relation to each other, a sub-assembly comprising an insulating tube of polygonal cross section, a plurality of U-shaped contactors slid able. onto said tube to be driven by the latter, a plurality of insulating members also slidable onto said tube and interposed between the re" spective contactors to space the latter, said sub assembly being insertable as a unit between said parallel end members, a shaft penetrating said end members and said tube and having driving engagement with the latter, a plurality of molded insulating members of like formv spanning said .shect metal members and secured to the latter independently of each other, each of said molded insulating members having a pair of spaced con tacte attached ,to the lower surface thereof for cooperation with one of said bridging contactors, each of said molded insulating members also hav ing at least one wiring terminal member and at last one fuse clip attached to the upper surface thereof, and a one-piece molded insulating ll'ltlll'l her also secured to one of said sheet metal mombers and abutting the ends of the molded insulating members aforementioned, said last mem tioned member having a plurality of fuse clips and wiring terminal elements attached thereto and arranged in alinement with the respective fuse clips aforementioned.

RALPH A. MILLERMASTER.