US2090764A - Electric switch - Google Patents

Description

Aug. '24, 1937.

R. A. MILLERMASTER s-Sheet l ELECTRIC SWITCH 2 Sheet Filed July 10, 1936 R. A. MILLERMASTER ELECTRIC SWITCH 2 Sheets-Sheet 2 Filed Jul-y 10, 1936 Y INSULATION Patented Aug. 24, 1937 UNITED STATES ELECTRIC SWITCH Ralph A. Miller-master,

to Cutler-Hammer,

Milwaukee, Wis., assignor Inc., Milwaukee, Wis., a

corporation of Delaware Application July 10,

6 Claims.

This invention relates to improvements in electric switches, and the invention relates more particularly to electric safety switches of the snap type.

An object of the invention is to generally improve the details of construction and the operation of switches of the aforementioned character.

Another object is to provide an improved and simplified form of arc snufling devices for attachment individually and directly to the stationary contact clips of such switches.

Another object is to provide an arc snufiing device comprising a pair of insulating elements 7 of like form adapted to envelop a contact clip of the switch, said elements and said clip being cooperatively formed to provide positive interlock- 1 ing connections between the former and the latter. 4

Another object is to provide a resilient metal member of novel form for cooperation with the insulating elements to retain the same in assembled relation to the contact clip.

Another object is to provide an arrangement wherein said resilient metal member is properly insulated from the live parts of the switch.

Another object is to provide an arc snuifer which is particularly well adapted for use with a switch of the free-end, knife-blade type.

Another object is to provide improved and simplified means for effecting snap operation of the switch to open-circuit or closed-circuit position of the parts. Another object is to provide an'improved form of operating handle and handle attaching means for switches of the aforementioned character.

Other objects and advantages of the invention will hereinafter appear.

The accompanying drawings illustrate a pre ferred embodiment of the invention which will 40 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 scope of the appended claims. In the drawings, Figure 1 is a top plan view,

- half-size, oi. an enclosed or safety switch of the snap type,-the hinged cover of the sheet metal casing of the switch being shown fragmentarily in open position,and a portion of the side wall 01 the casing which carries the cover latch being broken away. I

Fig. 2 is a fragmentary vertical sectional view, slightly greater than normal size, on the line 22 0! Fig. 1, showing in detail the interlocking connections between the insulating arc snuifer ele- 1936, Serial No. 89,884

ments and the stationary contact clip, and illustrating the relative positions of the'parts when the-switch blade is in circuit closing position.

Fig. 3 is a fragmentary vertical sectional view, on the line 3--3 of Fig. 1,certain of the parts being shown in elevation. Fig. 3a is a fragmentary elevational view of certain of the parts, looking in the direction of the arrows 3 4 of Fig. 3.

Fig. 4 is a side elevationalview of certain of the switch parts shown in Fig. 1,the switch casing being omitted,and certain of the parts being broken away or in section.

Fig. 5 is a fragmentary elevational view, as seen from the right-hand side of the device in Fig. 1. Fig. 6 is a fragmentary 'elevational view of certain of the switch parts, as seen from the opposite side of the casing wall in Fig. 5, and v Fig. '7 is a side elevational view, on a reduced scale, of one of the duplicate insulating arc'snuffing elements, showing .the form of the recess walls, which are shown in section in Fig. 2.

Referring to the drawings, the numeral l0 designates a base molded from a suitable insulating material to the form illustrated in Figs. 1 and 4. Base II] when positioned within the sheet metal housing II is rigidly attached to the bottom wall ll of the latter, as by means of three upper surface adjacent to one end thereof with a pair of metal blocks or plates iii of approximately L-shape which are attached thereto by bolts M (Fig. 4) and i5 (Figs. 1 and 4). Each bolt H with its nut ll (Fig. 4) likewise provides for attachment of the post or support i6 which pivotally carries one end of a knife-blade contactor ll. Each bolt IS with its nut l5"- likewise provides for attachment of a tubular soldering terminal elementJB of well known form.

' Each contactor ll preferably has attached to opposite sides thereof, by rivets IS, a pair of relatively thin fiat insulating plates 20 of like form. The projecting lower ends of said plates 20 are adapted to engage the rib l0- formed upon the upper surface of base ID to limit the circuit closing movement of the contactors (see Fig. 4). Plates 20 are provided with slots or notches opening in a direction away from the point of pivotal support of the contactor, as shown at 20* in Fig. 4. Said notches are adapted to accommodate the crank portion of a switch actuating element 2i, said crank portion preferably having telescoped thereonto prior to bending of element 2| an insulating tube 22 to properly insulate said element from the contactors.

5 Arranged in spaced relation tothe pivot posts l6 are a pair of one-piece resilient sheet metal contacts 23 of identical form, as shown in section in Fig. 2 and in dotted lines in Fig. 4. Contacts 23 are of constricted U-shape in vertical 10 crosssection (Fig. 2), the arms 23*, 23 being biased towardeach other and the upper ends thereof being flared as shown at 23, 23 to facilitate insertion of the contactors H therebetween. Partly sheared and bent outwardly and upwardly from the arms of each contact 23 at the enlarged lower end portion of the latter are a pair of substantially horizontal tongues 23 and 23 Each contact 23 is rigidly secured to base H! as by means of a bolt 24 the threaded shank of which extends upwardly through a passage in base in, penetratesan opening provided in the base portion of the contact, and takes into a tapped opening in a metal plate 25. Plate 25 is further attached to base H] by a bolt 25 2B the shank of which threads into a second tapped opening in said plate. Said shank extends upwardly a sufficient distance to penetrate a clearance opening provided in the tubular soldering terminal element 2! of well known form,

a nut 26 cooperating with said shank to clamp terminal 27 in fixed position.

To minimize arcing between each contact 23 and its cooperating contactor l1, and to thereby increase the life, the current controlling capacity and the safety characteristics of the switch as a whole, I provide for each 'contact 23 an arc snuffing device designated in general by the numeral 28. Each of said devices comprises a pair of members 28 of identical form which are pref- 40 erably molded from a suitable heat-resisting insulating material. The adjacent faces of members 28 are complementally recessed, as shown in 'Figs. 2 and '7 to jointly accommodate all parts of the stationary contact 23 associated therewith,--the arrangement being such that in the open circuit position of contactor I! the adjacent faces of members 28 may be brought into engagement with each other to completely enclose the contact 23. Members 28 are normally biased toward each other by a substantially U-shaped resilient metal clip 29 the respective arms of which seat in grooves 28 of corresponding shape upon the outer surfaces of the respective members 2B 'between the upper and lower ends of the latter. The free ends of the arms of member 29 are flared, as shown at 29 in Fig. 4, to facilitate insertion thereof into said grooves.

Members 28 are likewise preferably provided at the forward and rear sides thereof with complementary recesses 28 and 28 any pair of which are adapted to accommodate at least parts of the connecting portion 29 of member 29 (see Fig. 4). Each arm of member 29 is preferably provided with an inwardly extending hemispherical boss or projection, and each groove 28 is provided with a pair of hemispherical depressions, located at corresponding distances from the respective ends. thereof to selectively accommodate said bosses, whereby accidental separation of clip 29 from members 28 is prevented. One of said depressions is shown in dotted lines at 28 in Fig. 4. As will be understood, the member 29 is so assembled with respect to the members 28 that the connecting portion 29 is at the end of 7 said members which is remote from the pivot.

point of contactor H. The members 28*, however, may be reversed with respect to contact 23 and with respect to clip 29.

The members 28 of the arc snuffing device are restrained against substantial sliding movement relatively to contact 23 and with respect to each other as by means of the auxiliary recesses'28 which accommodate with a loose fit the aforementioned horizontal tongues 23 23 (Fig. 2). The arrangement is such that upon initial engagement of each contactor IT with the beveled edges 28 28 of members 28 the upper ends 28 of the latter will be spread apart against the bias of member 29, and upon continued circuit closing movement of contactor I! the members 28 will assume the positions thereof shown in Figs. 1 and 2. That is to say, the forward edges of said members will be spread apart to the required degree to accommodate contactor l1 whereas the rear edges thereof will be biased into engage ment with each other. As hereinafter describer, I preferably provide means for effecting movement of contactors H to opposite extreme positions thereof with a snap action, and the arc snufiing members 28and members 29 are so constructed and arranged as to add only a negligible amount of resistance to such movements of the contactors.

The switch actuating mechanism is preferably so constructed that in the event of breakage or disablement of the snap action spring, the contactors H may be moved to open-circuit posi-.

tion by manual operation of the switch handle, but in such event the contactors I! may not be moved to circuit-closing position pending repair or replacement of the snap action spring. It is to be understood that the snap action mechanism is adapted to become effective upon the contactors I! just prior to disengagement of the latter from the stationary contacts, wherefore the subsequent rapid movement of said contactors between the relatively large flat surfaces 28 on members 28 will tend to cool and extinguish any arcs formed incident to separation of the contactors from the contacts. Moreover,

. when in the circuit interrupting movement of contactors I! the same are disengaged from members 29 the entire adjacent fiat faces of the latter will be snapped into engagement with each other, under the bias of the respective members 29, thus completely enclosing the contacts 22 with which they are associated to further assist in and insure quenching or snufiing of an arcs so -formed.

The switch herein describedand illustrated has a rating of amperes at 575 volts A. C.- If it is desired to provide a switch of substantially lower rating or current controlling capacity, the arc snufiing devices, including members 28 and 29 may be entirely omitted without in anywise affecting the construction or assembly of the other switch parts. Moreover, the arc snufling devices may be readily removed to permit inspection, repair or replacement of the respective contacts by'merely manually withdrawing the members 29, whereupon the members 28 are free to be removed laterally from their associated contacts. or the member 29 0f each arc snufling device may be permitted to remain in position and the forward edges of members 28 may be spread apart manually to effect disengagement of the lower walls of auxiliary recesses 28 from the tongue 23, 23, whereupon the complete arc snufiing device may be lifted vertically out of interlocking engagement with its contact 23. The reverse of this procedure may, of course, be followed in 20 to each other.

lar end portion 30* one flat face of which is adapted to bear against the adjacent flat face of a punched and stamped sheet metal member 3|, the other face of the latter being adapted to bear against the inner surface of the side wall N of the switch casing (Fig. 3). Member 3| is provided with an opening 3|, the form of which is illustrated in Fig. 3a. The main portion of the peripheral wall of opening 3| is in the form of an arc of a circle, to provide a bearing for the arc-shaped peripheral edge of the reduced portion 3|] of the hub member. Said portion is also provided with a flat edge 30, and the opening 3| is provided with a. pair of flat wall portions 3|, 3| arranged at a predetermined angle By this means a predetermined degree of lost motion is provided between hub member 30 and member 3|. Member 3| is provided with integral portions 3|, 3| which are slightly offset from the main body thereof (Figs. 5 3 and 3a) to minimize friction between said memberand the inner surface of easing wall U. The portion 3| is provided with an integral lug 3| which is bent inwardly at substantially a right angle with respect to said casing wall, and the portion 3| is similarly provided with an integral lug 3P The lugs 3", 3| are spaced a predetermined distance apart and in overlapping relationship to one arm of crank-member 2|, as best illustrated in Fig. 1,-to provide a predetermined degree of lost. motion between member 3| and said crank member. Casing wall is provided with a circular opening (Fig. 3) and I prefer to position within said opening, in bearing relationship to the wall thereof a circular washer 32,-said washer being of slightly greater thickness than wall II for a. purpose to be described. I

Hub member 30 is provided with a further reduced portion 30 of the contourbest illustrated in Fig. 3a,the same having parallel flat sides 30. and 30*. Washer 32 is provided with an opening of a shape corresponding" to the cross sectional contour of portion 30 whereby these parts are constrained to rotate with each other.

The operating handle 33 is non-rotatably attached to hub member 30 in the following manher. A stamped sheet metalmember having a main body portion 34 of substantially circular contour is adapted to seat against the outer sur- .face of washer 32 (Fig. 3), and said portion is provided with an opening to non-rotatably accommodate the portion 3|! of the hub member. The handle 33 is provided with a portion 33 of. inverted channel-shape which overlies said body portion in the relationship best illustrated in Fig. 5, it being understood that the longitudinal center line of handle 33 is parallel with the flat sides 30 and 3|! of hub portion 30 Interposed between handle portion 33' and body 6 portion 34 is a pair of spacedmetal members 35 and 36, all of said elements being rigidlyattached to each other, as by means of four rivets 31, the tapered heads of which (not shown) are positioned in countersinks in the surface of por- 70 tion 34 adjacent to casing wall ll 75 is angled away from casing wall |l to a slight degree, as shown in Fig. 1. The shoulder provided at one end of projection 34 is adapted to abut against the edge of a right-angled lug 38* form'- ing part of a bracket member 38 which is rigidly attached to wall II, as by means of rivets 39 (see Fig. 5) to positively limit the degree of rotary movement of handle 33 in one direction. The shoulder provided at the other end of projection 34 is adapted to abut against the edge of a right-angled lug 40* forming part of a bracket member 40 which is rigidly attached to wall ll as by means of rivets 4|. The lugs 38 and 4|] are respectively provided with perforations shown, respectively, in dotted lines at 38 and 40 in Fig. 5; and flange 34 is provided with a perforation 34 and a notch 34 (see Figs. 3 and 5), which are selectively registerable with the aforementioned lug openings 38 4|! to provide for insertion of the hasp of a padlock of' suitable form, whereby the switch may be locked in open-circuit or closed-circuit position.

As best shown in Fig. 3, the handle portion 33 is provided with an opening to afford clearance for the still further reduced and threaded end portion 30 of the hub member,a nut 42 being engaged with portion 30 to clamp the aforedescribed parts in assembled relation. Portion 30 is preferably provided with a passage extending diametrically therethrough adjacent to the outer end thereof, and nut 42 is provided witha plurality of kerfs extending from the outer end thereof to provide for insertion of a cotter pin 43, in the /manner illustrated in Fig. 5, whereby loosening of nut 42 is positively prevented.

To limit the degree of circuit-interrupting movement of contactors I1, I prefer to provide a stud 44 projecting inwardly from the casing wall I l to be engaged by the right-hand arm of crank member 2| (see Figs. 1 and 6). The reduced end 44 0f stud 44 penetrates an opening provided in wall II and a washer 45 and is upset over the latter, as shown in Figs. 1 and 5.

Referring to Figs. 1 and 6, it will be noted that the portion 3| of member 3| is provided with an integral offset lug 3| which is provided with an opening to registerwith openings provided in the enlarged and shouldered ends of a pair of metal members 46 and 41 arranged on opposite sides thereof,-a headed rivet 48 being inserted through said openings and upset as shown to provide a pivotal connection between said parts. Members 45 and 41 are ofiset into engagement with each other throughout the major portion of the length thereof from a point adjacent to the pivot end thereof,the free ends of said members being reciprocable through an opening provided in the lug 49 forming a part of bracket 49 which is attached to casing wall II as by means of rivets 50. .Lug 49 is formed to provide a pair of surfaces angled toward each other to provide a sort of knife-edge bearing for one end of a coiled compression spring 5| which surrounds members 45 and 41,the other end of said spring being engaged with the aforementioned shoulders at the enlarged ends of members 45 and 41.

A latch member 52 is pivotally supported in spaced relation to casing wall II", as by means of pin 53,-a bracket 54 being attached to said wall, as by means of rivets 55. The horizontal portion 54 of said bracket has an opening to provide clearance for latch 52 and to insure proper alinement thereof with an opening or slot (not shown) provided in the casing cover H". Member 52 is provided on the portion 52' thereof with an abutment to accommodate and retain one end of a coiled'compressionspring 56,the'other end of which engages a boss or abutment formed upon the lower face of the horizontal portion 54 of said bracket. Latch 52 is also preferably provided with an opening 52 to accommodate the ;hasp of a suitable padlock, to provide for locking cover H in closed position, or to prevent complete closure thereof, if desired.

The handle 33 which is formed of sheet metal has the grip portion 33 thereof drawn or swaged to the hollow form illustrated, and in a manner to avoid exposure of any out edges.

It is thought that the operation of the snap switch mechanism will be obvious from the foregoing description. It may be pointed out, however, that with the various parts in the respective closed-circuit positions shown in Figs. 1 and 5, upon initial downward-movement of handle 33, the lost motion between the hub member 30 k and member 3| is first taken up. That is to say (see Fig. 3a) the hub 30 is permitted to move rather freely until the ilat edge 30 of hub portion 30 engages the fiat wall portion 3| of opening 3| Therefipon member 3| rotates along with hub member 3|! to effect compression of spring 5|. Before the toggle (represented by the pivot pin 48) reaches dead center the lug 3| (Figs. 1 and 6) will engage the right-hand arm of crank member 2| to positively initiate disengagement of contactors II from their associated stationary contacts 23. As heretofore pointed out, said contactors I! may .be disengaged by the operating means independently of spring 5|, but under normal conditions spring 5| will become efiective prior to complete disengagement of said contactors to effect snap movement thereof to circuit interrupting position. Such movement of.- contactors l 1' is limited by engagement of crank member 2| with stop pin 44, as aforedescribed. The are snufilng devices will act in the manner aforedescribed to minimize the degree of arc formation and to efiectually extinguish or snufl any arcs formed incident to the operation.

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

1. In an electric switch, in combination, a molded insulating base, a contactor pivotally supported at one end upon said base, a resilient stationary contact member supported by said base I and .into and out of engagement with which said contactor is adapted to move, said contact having.lugs extending from opposite sides thereof in a plane spaced upward1y'from said base, a pair of heat-resisting molded insulating members 5 of like form and dimensions, said members-havingadjacent-flat faces normally in engagement with each other and the same being ,complementally recessed to accommodate said contact 'and said lugsand to normally completely en-' '6 close the same, said lugs cooperating with certain walls of said. recesses toprovide interlocking connections between said parts, and a substantially Ueshaped resilient metal clip supported solely by said members joint the-arms of said clip ex- 65 tending from one vertical; side of said pair of members in a direction substantially parallel tov the. upper surface of said base, the arms of said clip being arranged-toembrace the respective outer sides of said members in upwardly spaced 70 relation to said base and to accommodate therebetween the free end of said contactor during engagement of the latter with said contact, the

adjacent corner edge portions only of said members which are first engaged-by said contactor .76 during. circuit closing movement of the latter being beveled to facilitate movement of said contactor therebetween to effect the necessary degree of separation thereof, the remaining edge portions of said members being normally adapted for flatwise' engagement with each-other. I 5

2. In an electric switch, in combination, a substantially' U-shaped resilient stationary contact the arms of which are biased toward each other, lugs formed integrally with the respective arms and extending laterally therefrom at points in- 10 termediate the upper and lower ends thereof, an arc snufi'er attachment comprising a pair of molded insulating members of like formand dimensions, said members having interior comple- I mentary recesses to accommodate said contact 15 and said lugs and to normally completely enclose the same, the walls of said recesses cooperating with said lugs to prevent accidental endwise displacement of said parts when assembled, a sub stantially U-shaped resilient metal clip supported 0 entirely by said members jointly in a plane spaced upwardly from the lower ends of the latter, the arms of said clip embracing said members to normally yieldably bias the adjacent faces thereof into engagement with'each other, the free ends 5 of said arms being arranged to provide clearance for a contactor of suitable form insertable between said members for engagement with said contact, and said members having beveled edges to facilitate movement of said contactor there- 30 mensions, saidmembers having interior comple- 40 mentary recesses to accommodate said contact and said lugs and to normally completelyenclose the same, the walls of said recesses cooperating with said lugs to prevent accidental endwise displacementof said parts when assembled, asub- 4 5 stantially U-shaped resilient metal clip supported entirely by said members jointly in 'a plane spaced upwardly from the lower ends of the latter, the arms 'of said clip embracing said members to normally yieldably bias the adjacent faces there- '50 of into engagement with each other, 'the free endsof said arms being arranged to provide clearance for a contactor of suitable form insertable between said members for engagement with said contact, said members having beveled edges to facilitate movement of said contactor therebetween, and said members-having relatively large fiat surfaces opposed to each other above said stationary contact, said surfaces'extending to the upper ends of said members and the same being engaged by said contactor upon disengagement of the latter from said contact to assist in cooling and extinguishing :the arc. 4. In an 816', snuif er for electric switchesof the safety type, in'combination, a movable contact pivotally supported at one end, a one-piece resilient stationary contact clip of constricted- U-shape in vertical ,cross section said. clip having tongues formed integrally with the respective arms thereof and extending laterally in opposite directions from said arms in a plane above the lower enslsgoi the latter, a pair of heat-resisting molded ulating members of identical shape and dimensions, said members being complementally recessed to jointly receive and to nor- 7 mally entirely enclose said contact clip, said members having internal auxiliary recesses to accommodate the respective tongues, whereby said members when assembled are jointly restrained against endwise separation from said clip but are permitted to move laterally to the required extent with respect to each other, the adjacentfaces of said members having bevels formed at the upper corners thereof, either set of bevels being adapted to facilitate movement of said contact between said members into engagement with said clip, said members having external grooves formed therein in planes parallel to the plane of their adjacent faces, a substantially U-shaped resilient sheet metal clip the arms of which are jointly insertable into said grooves from one vertical side edge of said pair of members in a direction toward the pivot point of said contact, whereby the connecting portion 20 of said resilient clip is positioned at a point re- 'mote from said pivot point, said grooves having depressions formed therein respectively, and said arms having bosses formed upon the respective innersurfaces thereof for cooperation with said 5 depressions to yieldably restrain said metal clip against separation from said members.

5. A switch comprising, in combination, a

pivotally mounted blade, a stationary contact clip having opposed resilient jaws biased toward 30 each other for engagement with a portion of said blade when moved therebetween, said jaws having flared upper ends to facilitate engaging movement of said blade, a pair of molded insulating 'arc snuiling members normally completely enclos- 35 ing said contact clip but separable from each other in the plane of said blade, said clip having a laterally extendinglug formed integrally with each jaw'adjacentto the lower endthereof, said insulating members having recesses to re- 40 spectively accommodate said lugs to prevent substantial sliding movement of said members relatively to said clip and to each other, said insulating members having the adjacent upper corners thereof beveled to facilitate movement of the 45 blade therebetween, said insulating members having parallel grooves formed in the outer sides thereof and extending from one side edge thereof to the other, a substantially U-shaped resilient metal member the arms of which are jointly in- ,50 sertable into said grooves from the side remote from the blade pivot, said arms each having an inward projection, and said grooves having recesses to accommodate the respective projections, whereby said metal member, said insulating members and said contact clip are yieldably and releasably retained in assembled relation.

6. A switch having in combination, a pivotally mounted blade, a stationary contact clip having a pair of resilient jaws biased toward each other for slidable engagement with said blade when moved therebetween, said jaws hav-. ing flared upper ends to facilitate engaging movement of said blade, 9. pair of arc snufllng members of molded insulating material normally completely enclosing said contact clip but separable from each other in the plane of said blade, said clip having a tongue partly sheared and bent laterally from each jaw adjacent to the lower end thereof, said insulating members having recesses formed in the inner surfaces thereof to respectively accommodate said tongues to prevent substantial sliding movement of said members relatively to said clip and to each other, said insulating members having the adjacent upper corners thereof beveled to facilitate movement of the blade therebetween, said insulating members being formed to jointly provide a groove of reotangular channel-shape in cross section surrounding the same adjacent to the lower end thereof, a substantially U-shaped resilient metal member the arms of which are insertable into said groove on the outer sides respectively of said insulating members, whereby the connecting portion of said metal member is accommodated within said groove at the side remote from the blade pivot, said arms having outwardly bent ends to facilitate insertion thereof into said groove, said arms also having hemispherical'bosses formed on the inner surfaces thereof adjacent to said ends, said groove having recesses adjacent to one side edge of said insulating members to accommodate said bosses whereby all of the aforementioned parts are releasably retained in assembled relation, and said groove having other recesses adjacent to the other side edge of said insulating members, whereby the latter may be assembled in reverse relationship to said 'contact clip and to said metal member.

RALPH A. MILLERMASTER.

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