US2210037A - Electric switch - Google Patents

Description

. Aug. 6, 1940.

Filed Feb. 2, 1939 ZSheets-Sheet 1 a0 /5 as II H m /5 14 a! m /0 m /0 3! 34 32' 50 5 a 5a 53 5 '8 J4 6 51 55 54 a/z /a 34 /5 m m 55 5/ 1940. G. J. MEUER 2.210,037

ELECTRIC SWITCH I Filed Feb. 2,'1939 2 sheets-sheet 2 a4 54 I4 /5 1/ 0/51 l id/ e 5554 54 10 I4 l5 55 as 35 Patented Aug. 6, 19.40

ELECTRIC SWITCH George J. Meuer, Milwaukee, Wis assignor to Cutler-Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Application February 2, 1939, Serial No. 254,264

16 Claims.

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

An object of the invention is to generally improve the details of construction and assembly of the parts of such switches, and the electrical characteristics of such switches when in use.

Another object is to provide one-piece combined contact and terminal members of novel form.

the stationary switch parts relatively to each other and to the insulating supporting base.

Another object is to provide a novel form of insulating supporting base for electric snap switches of the tool handle type. t

Another object is to minimize the number of fastening elements required for attachment of the switch parts to the insulating base. I

Another object is to provide a novel form of sheet metal guard for the coiled compression spring of a switchof' the aforementioned character.

arrangement of the switch parts whereby substantial dust-tightness of the side and end walls of the base recess is insured.

Other objects and advantages of the invention will hereinafter appear.

The accompanying drawings illustrate an em bodiment of the invention which will now be described; it being understood that the invention is susceptible of embodiment in other forms without departing from the scope -of the appended claims.

The snap switch herein'disclosed is in general of the character described and claimed in my prior Patents, No. 1,889,259, dated Nov. 29,- 1933, and No- 1,977,078, dated Oct. 16, 1934.

In the drawings (all double scale), Figure 1 is a central longitudinal sectional view of a snap switch of the tool handle type, as constructed in accordance with my invention, certain of the parts being shown in elevation.

Fig. 2 is a view similar to Fig. 1, the section being taken in a plane along one side of the base recess,-showing one set of the one-piece combined contact and wiring terminal members and the cooperating contactor, the operating elements of the switch being shown in elevation.

Fig. 3 is a top plan view of the molded insulating base of the switch showing certain of the one-piece combined contact and terminal menibers and the contactors in assembled relation, one of the combined contact and terminal members. being omitted, to illustrate the form of the base recess, and the contact portion of another of the I members being broken away.

Another object is to facilitate assembly of Another object is to provide a novel form and Fig, 4 is an end view of the switch, illustrating Y the novelmeans to provide for end wiring of the switch. I

Fig. 5 is a vertical section, approximately on the line 5-5 of Fig. 2,'certain of the operating elements being shown in elevation. T

Fig. 6 is a perspective view of one of the onepiece combined contact and terminal members, and showing the backing plate or nut having a tapped opening for cooperative engagement by the threaded shank of a binding screw, and

Fig. 7 is a perspective view of the punched and stamped sheet metal guard for the spring.

Referring to the drawings, the numeral l0 designates a base produced by a straight-line molding operation from a suitable insulating material, such as bakelite". Base I0 is preferably 01 substantially rectangular or box-like contour, as shown, the same being provided with a relatively large substantially rectangular recess H which opens to the upper surface thereof. Formed integrally with the bottom wall of recess II is a rib having a flat upper surface I2, upon which slides the insulating plate l3, the latter having attached thereto a pair of bridging contactors [4 as by means of rivets IS, in the manner illustrated in Fig. 9 of my prior Patent No. 2,077,577, dated April 20, 1937.! The end walls of recess II are provided with vertical ribs "5 of identical form, against which plate I3 is adapted to abut in its respective opposite extreme positions. The operating mechanism of" my switch is quite similar to the mechanisms shown in my prior patents aforementioned, see, for instance, Fig. 3 of my Patent No. 1,977,078. Such mechanism, in general, comprises a metal yoke H, the hooked ends of the arms of which are pivotally supported in diametrically opposed openings provided in a boss or bulge l8 in the metal top plate 19.

Pivotally supported by yoke I1 is a. flat punched insulating plate 20, the lower end of which has a lost-motion connection with the end walls of a slot or opening 2| (Figs. 1 and 3) provided in plate I3. The lower end of a coiled compression spring 22 is telescoped onto the reduced and shouldered upper end of plate 20. Non-rotatably secured to the peripheral wall-of an opening provided in boss l8 (Fig. 1) is an externally threaded hollow metal bushing 23, within which is pivotally supported, as by a pin 24, a metal operating lever 25 of circular form in transverse cross section, but of varying size at difierent points in its length. Thus, at the point of pivotal support of lever 25 the same is of a size to provide for substantial closure of the passage in bushing 23. As

best illustrated in Fig. 5, pivot pin 24 has a headat one end which seats within a countersink in the outer surface of bushing 23 in a relation to provide clearance for the threads upon a clamping nut or nuts (not shown) to be associated with the bushing. In like manner the shank end of pin 24 is upset within a corresponding countersink at a diametrically opposed point in the surface of bushing 23 in a relation to provide the aforementioned clearance for the clamping nut or nuts.

Lever 25 is provided with a rounded or substantially spherical lower end 26 (Fig. 1) which is adapted to abut or engage the concavity 21 provided in the upper end of the spring guard 21. As will be understood from consideration of .Fig. 7, the spring guard 21 is pressed or stamped to the form illustrated from a relatively long punched sheet metal plate of substantially rectangular contour, the opposite ends of such sheet having notches initially formed therein to provide in the finished article the relatively short arcshaped notches 21 and 2'? which insure clearance between spring guard 27 and the aforementioned plate 20 in all relative positions of said parts. The opposite sides of the aforementioned sheet metal plate when formed as shown in Fig. '7 become refiexed to provide slots 2?, 21 which extend upwardly throughout the entire length of guard 27, and provide, in effect, cut-away portions at diametrically opposite sides of the concavity 21' As best illustrated in Fig. 2, slots 27 and 2'! provide clearance between guard 21 and the respective arms of the yoke 87, the side walls of each slot 27 and 27 cooperating with the respective arms of yoke I? to prevent substantial rotary displacement of guard 21?. As will be noted from Fig. 7, the length of guard 27 is at least as great as the normal diameter, or greatest dimension of the concavity 2! provided at the upper end of the guard. The advantages of this form of spring guard, and the novel manner in which the same may be produced, will be at once apparent to those skilled in the art.

Base Ill is preferably provided with a flat lower surface l which is interrupted at two longitudinally spaced points to provide passages to accommodate the rivets 28, the heads of which are located in countersinks' Ill and Ill in said lower surface Ill. The shanks of rivets 28 are upset over the metal top plate IE! to secure the latter in position, a fiat punched insulating plate 29 being interposed between top plate l9 and the upper surface of base l0. As shown in Figs. 1, 2 and 4, insulating plate 29 is of a shape and size to completely cover the upper surface of base I 0, with the exception of small portions of the integral barriers 30 which extend throughoutthe entire depth of base l0 and extend longitudinally beyond the main body of the latter, to insure an adequate creepage space between the pairs of wiring terminals and binding screws at the respective ends of base l0. As shown in Figs. 1, 3 and 5, the rib I2 is provided with a curved-bottom recess l2 to provide clearance for the oscillatory lower end of plate 20.

Base I0 is provided at each of the four corners thereof with like grooves 3| (see Fi 3), two in each end wall. Grooves 3| open to the upper surface of base l0. and the same extend downwarly throughout the major portion of the depth of recess II. The opposed walls of the respective grooves 3| are provided with relatively small substantially inverted L-shaped recesses, the

horizontal portions of which are designated bythe numeral 3| and the vertical portions of which are designated by the numeral 3|. Each end wall of recess II is also provided adjacent its lower end, with a pair of integral portions 3| alined with the respective grooves 3|, but of greater width than the latter. The portions 3 l are recessed, as shown at 3l in Figs. 2 and 3, to provide upwardly opening pockets, and said portions 3d are further provided with upwardly,

downwardly and laterally opening grooves 31, which provide for downward passage of circuit wires (not shown), the ends of which have been clamped in position by the heads of binding screws 32.

In accordance with my invention, I provide two sets of one-piece combined stationary contact and wiring terminal members, the two members 33 comprising the upper stationary contacts being positioned at one end of base it, and the two members3 l comprising the lower stationary contacts being positioned at the other end of said base. The members 33 and 33 are preferably punched from a sheet of suitable resilient conducting material, such as hard copper, and stamped to the respective forms thereof shown. One of .the members 33 is shown in detail in Fig. 6 as comprising a relatively wide terminal portion of substantially inverted J-shape, the relatively long arm of the J being designated by numeral 33 the relatively short arm thereof being designated by numeral 33*, and the connecting portion thereof being designated by numeral 33.

Formed integrally with the relatively short arm 33 and extending downwardly and laterally therefrom at a predetermined angle thereto, is a relatively narrower resilient contact portion 33 a portion 33 of which is oifset downwardly from themain body thereof to provide a contact tip, the end of which is preferably bent upwardly or flared, as shown at 33 The arm 33 is provided with an opening 33 to provide ample clearance for the threaded shank of one of the binding screws 32, the head of which screw may be drawn toward the outer or exposed surface of arm 33 to clamp the bared end of a circuit wire (not shown) against the latter. The means for affording such clamping action of the screw head comprisesa substantially rectangular plate 35 of metal, such as brass, which is adapted to be positioned against the inner surface of arm 33 in a relationship substantially flush with the lower end of the latter. Plate 35 is provided with an extruded and tapped opening 35 for cooperation with the shank of said screw 32.

' In practice the screw 32 may be assembled with respect to member 33 and plate 35 as shown at the right-hand side-of Fig. 2, and the sub-assembly inserted as a unit into proper position relatively to base l0, the lower end portions of arm 33 and plate 35 fitting into one of the aforementioned pockets 3W; the connecting portion 33 of the J being accommodated in a substantially flush relation to the upper surface of base II), by one pair of horizontal portions 3| of the inverted L-shaped recesses, and the short arm 33 of the J being accommodated by one pair of vertical portions 3| of said recesses. As will be apparent from Fig. 2, the respective groove 3| in an end wall of the base recess is of suflicient width and depth to afford ample clearance for the shank of the screw 32. Also as shown the contact portion 33 of the member 331s so formed and positioned as to provide clearance between the same and the shank of the screw 32in the extreme inner position of the latter.

The wiring terminal portions of v the members 34 are of the same shape and dimensions asthe corresponding portions of the aforedescribed members 33, and are assembled with respect to base ID in the aforedescribed manner, as shown parts of said members in the event of a pull or at the left-hand side of Fig. 2. The contact portions of members 34 are bent laterally as shown at 34 in Fig.2 to provide clearance between the same and the shank of a screw 32, and then vertically downwardly as shown at 3 to lie close to one of the end walls "of recess II. The free ends 34 of the contact portions of members 34 are bent to normally extend laterally-and upwardly toward the tips 33 of the respective con: tact portions 33 aforedescribed, whereby upon assembly of the parts as shown in Fig. 2 said ends 34 are engaged under a predetermined degree of tension with the lower face of plate l3 and/or the contactors l4 carried by the latter. Said free ends 3! are bent downwardly or flared as shown at 34 in Fig. 2 to facilitate movement of contactors I4 into engagement therewith, and to prevent stubbing of said contactors thereagainst. As will be apparent from consideration of Fig. 2, when all of the switch parts are in assembled relation theinsulating cover plate 29 acts to positively retain the several combined contact and closed arcing chamber for the respective sets of switch contacts and contactors, plate 36 having a slot formed therein to provide clearance for the aforementioned plate 20.

As will be apparent from consideration. of Figs. 2, 3 and 4 the side walls of base recess II are closed throughout the length and depth thereof, whereas the openings formed in the respective end walls of the recess by the slots 3| are effectively closed by the wiring terminal portions of members 33 and 34, and the binding screws associated therewith, when the switch parts are assembled. The insulating cover plate 29, metal top plate l9, bushing 23 and lever 25 cooperate to provide for substantial closure or dust-tightness of the recess or switch chamber l l.

Although I have shown a switch of the one-hole mounting type, it will be understood that other forms of mounting means and other forms of operating elements (of the character shown in my Patents Nos. 1,889,259 and 1,977,078) may be substituted therefor if desired.

By reason of the fact that the stationary contact-and wiring terminal portions of.the switch elements are of one-piece construction the current carrying and current controlling characteristics of the switch parts are improved and a relatively long life of the switch as av whole is insured. V

It will be understood that during assembly of the switch parts the members 34 and their associated plates 35 and screws 32 are first inserted into the corresponding recesses at either end of base I0, after which insulating plate [3 with contactors I4 attached thereto is insertedzinto recess ll, whereupon the members 33 with their associated plates35 and screws 32 arejinserted into the corresponding recesses at the qother end of base l0. The other elements of the: switch are thereafter positioned in an obvious manner, and finally all of the parts are completelygl and permanently attached to base l0 by'me ns of'the aforementioned rivets 28. f

By reason of the aforedescribedin erlocking connections between the upper and lower ends.- of the wiring terminal portions of members 33 v and 34 and the recesses and/or pockets: provided therefor in base I0, I prevent the possibility of deformation, distortion or dislocation of any strain uponthe circuit wires after clamping of the bared ends of the latter (not shown) by the heads of binding screws 32.

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

1. In an electric switch, in combination, an in- I sulating base adapted to be formed by a straightline molding operation, said base having a relatively deep recessformed in the upper surface thereof, said base having an upwardly opening groove formed in an end wall of said recess and extending downwardly throughout the major portion of the depth of the latter, said end wall of the recess having a pair of relatively small alined grooves formed therein on opposite sides of said first mentioned groove and opening to the upper surface of said base, said end wall having a lateral extension adjacent to the lower surface of said base, said extension having an upwardly opening pocket formed therein, a one-piece combined contact and terminal member having a relatively narrow resilient contact portion thereof located within said recess and a relatively wider terminal portion the lower end of which is adapted to'fit within said pocket, the upper end of said terminal portion extending inwardly in a plane substantially flush with the upper surface of said base and then downwardly into said relatively smallalined grooves, a binding screw associated with said terminal portion and adapted to clamp a conductor wire to the latter, said first mentioned groove being adapted to accommodate the shank of said binding screw, and an insulating plate rigidly secured to the upper surface of said base and adapted to secure said combined contact and terminal member in assembled relation to said base.

2. In an electric switch, in combination, an insulating base adapted to be formed by a. straightline molding operation, said base having a relatively deep recess formed in the upper surface thereof, said base having an upwardly opening groove formed in an end wall of said recess and extending downwardly throughout the major portion of the depth of the latter, said end wall of the recess having a pair of relatively small alined grooves formed therein on opposite sides of said first mentioned groove and opening to the upper surface of said base, said end wall having a lateral extension adjacent to the lower surface of said base, said extension having an upwardly opening pocket formed therein, a one-piece com-- bined contact and terminal member having a relatively narrow resilient contact portionthereof plane substantially flush with thefuppersurface of said base and then downwardly into said relae tively small alined grooves, a: binding screw associ'ated with said terminaljportiorr and adaptedxto clamp 'a conductor wire to the 'latter,. said i fl-rst mentioned groove being adaptedtoiaccommodate the shank of said binding. screw, and-arrinsulat r ing plate rigidly secured to theupperfsurface of i said base and adapted 1 to -secure :said'combined' contact and terminal memberinassembledi'i'elm tion to said base, the terminal portion offsaid member and said screw cooperating to provide said end wall by said first mentioned groove," ,1

J 3. In an electric switch, in-coinbination; an in sulating base adapted tobe formedby a straight- 'for substantial closure of the openingformedf-in upper surface of said base, said end wall having a lateral extension adjacent to the lower surface of said base, said extension having an upwardly opening pocket formed therein, a one-piece combined contact and terminal member having a relatively narrow resilient contact portion thereof located within said recess anda relatively wider terminal portion the lower end of which is adapted to fit within said pocket, whereby substantial lateral displacement of said lowerend is prevented, the upper end of said terminal portion extending inwardly in a plane substantially fiush I with the upper surface of said base and then downwardly into said relatively small alined grooves, a binding screw associated with said terminal portion and adapted to clamp a conductor wire to the latter, said first mentioned groove being adapted to accommodate the shank of said binding screw, an insulating plate rigidly secured to the upper surface of said base and adapted to secure said combined contact and terminal member in assembled relation to said base, and said extension having a relatively narrow upwardly, downwardly andlaterally opening groove formed therein and interrupting the outer wall of said pocket to provide for downward passage therethrough of a conductor wire clamped by said binding screw.

4. In. an electric switch, in combination, an insulating base adapted to be formed by a. straightline molding operation, said base having a relatively deep recess formed in the upper surface thereof, said base having an upwardly opening groove formed in an end wall of said recess and extending downwardly throughout the major portion of the depth of the latter, said end wall of the recess having a pair of relatively small ahfned grooves formed therein on opposite sides of said first mentioned groove and opening to the upper surface of said base, said end wallhaving a lateral extension adjacent to the lower surface of said base, said extension having an upwardly opening pocket formed therein, a one-piece combined contact and terminal member having a relatively narrow resilient contact portion thereof located within said recess and a relatively wider terminal portion the loweraend of which is adapted to fit within said pocket, the upper end of said terminal portion extending inwardly in a plane substantially flush with the upper surface of said base and then downwardly into said relatively small alined grooves, said terminal portion having a relatively large opening formed therein to provide clearance for the shank of said binding screw, a metal plate interposed between said terminal portion and the outer surface of the end wall of said recess, said'metal plate having a tapped opening for threaded engagement by the shank of said binding screw, and said first mentioned groove being adapted to accommodate the shank of said binding screw, the contact portion of said member being formed to provide clearance for the shankof said binding screw in the extreme inner position of the latter.

5. In an electric switch, in combination, an insulating base adapted to be formed by a straightline molding operation, said base having a relatively deep recess formed in the upper surface thereof, said base having an upwardly opening groove formed in an end wall of said recess and extending downwardly throughout the major portion of the depth of the latter, said end wall of the recess having a pair of relatively small alined grooves formed therein on opposite sides of said first mentioned groove and opening to the upper surface of said base, said end wall having a lateral extension adjacent to the lower surface of said base, said extension having an upwardly opening pocket formed therein, a one-piece combined contact and terminal member having a relatively narrow resilient contact portion thereof located within said recess and a relatively wider terminal portion the lower end of which is adapted to fit within said pocket, the upper end of said terminal portion extending inwardly in a plane substantially fiush with the upper surface of said base and then downwardly into said rel-.- atively small alined grooves, said terminal portion having a relatively large opening formed therein to provide clearance for the shank of said binding screw, a metal plate interposed between said terminal portion and the outer surface of the end wall of said recess, said metal plate having a tapped opening for threaded engagement by the shank of said binding screw, the lower end of said metal plate being also adapted to fit within said pocket in a relation substantially flush with the lower end of said terminal portion, and said first mentioned groove being adapted to accommodate the shank of said binding screw, the contact portion of said member being formed to provide clearance for the shank of said binding screw i the extreme inner position of the latter.

6. In an electric'snap switch, in combination, an insulating base adapted to be formed by a straight-line molding operation, said base having a relatively large substantially rectangular recess opening to the upper surface thereof, the end walls of said recess having alined upwardly opening grooves formed therein and extending throughout the major portion of the depth thereof, the opposite walls of each of said grooves having alined inverted L-shaped recesses formed therein and opening to the upper surface of said base, said base having integral extensions alined with, but of greater width than, said grooves adjacent to the lower surface of said base, each of said extensions having an upwardly opening pocket of substantially rectangular form in transverse cross section, one wall of each pocket being substantially flush with the outer surface 'of the recess end wall associated therewith, a pair v atively wide terminal portion the lower end of which is adapted to fit within one of said pockets and the upper end of which is bent to extend inwardly in a substantially fiush relation to the upper surface of said base and then downwardly to fit within the vertical portions of one of said sets of inverted L-shaped recesses, and each of said members also having a relatively narrower resilient contact. portion located within said relatively large recess, the tips of the contact portions at the respective sides of said recess bein arranged in overlapping relationship to each other.

7. In an electric snap switch,v in combination, an insulating base adapted to be formed by a straight-line molding operation, said base having a relatively large substantially rectangular recess opening to the upper surface thereof, the end walls of said recess having alined upwardly opening grooves formed therein and extending throughout the major portion of the depth thereof,'the opposite walls of each of said grooves having alined inverted L-shaped recesses formed therein and opening to the upper surface of said base, said base having integral extensions alined with, but of greater width than, said grooves ad-' jacent to the lower surface of said base, each of said extensions having an upwardly opening pocket of substantially rectangular form in transverse cross section, one wall of each pocket being substantially flush with the outer surface of the recess end wall associated therewith, a pair of one-piece combined contact and wiring terminal members, each of said members having a relatively wide terminal portion the lower end of which is adapted to fit within one of said pockets and the upper end of which is bent to extend inwardly in a substantially flush relation to the upper surface of said base and then downwardly to fit within the vertical portions of one of said sets of inverted L-shaped recesses, each of said members also having a relatively narrower resilient contact portion located within said relatively large recess, the tips of the contact portions at the respective opposite sides of said recess being arranged in overlapping relationship to each other, said contact portions being bent to bias said overlapped. tips thereof toward each other, a movable, flat plate of insulating material continuously interposed between said contact tips,

. and contactors carried by said plate and movable thereby into and out of bridging engagement with said overlapped contact tips.

8. As an article of manufacture, a one-piece combined contact and terminal member for electric snap switches of the'tool handle type, said member having a relatively wide terminal portion bent to substantially inverted J-shape in cross section, the upper and lower ends of said J being adapted for positive engagement with a vertically shouldered insulating base of suitable form, a relatively narrower resilient contact portion formed integrally with said terminal portion and extending laterally and downwardly from the short arm of said J, the free end of said contact portion being formed to provide for and to facilitate engagement therewith of a contactor of suitable form, said terminal portion having an openingformed at substantially the mid-point in the long arm of'said J to accommodate the shank of a binding screw, and the contact portion of said member being bent interrrmdiatejts ends to provide clearance for such screw shank.

9.- As an article of manufacture, a combined contact and wiring terminal assembly for electric snap switches of the tool handle type, said assembly comprising a one-piece unched and stamped resilient metal member having a relatively-wide substantially rectangular terminal portion bent to substantially inverted J-shape in cross section, the hooked end of said J being adapted for interlocking engagement with a suitable insulating base in a plane substantially flush with the-upper surface of the latter, the long arm of said J having an opening formed therein to provide clearance for the shank of a binding screw,;a-; relatively rigid substantially rectangular. me t'al plate positioned at the inner surface of said: long arm of the J, said plate having a tapped openingformed therein, a binding screw penetrating said clearance opening and having threaded engagement with said tapped opening,

whereby the head of said screw may be drawn into clamping engagement with the outer surface of said long arm of the J, a relatively narrow contact portion formed integrally with the short arm of the J and extending downwardly therefrom, said contact portion being offset intermediate its ends to provide clearance for the shank of said screw, the free end of said contact portion being adapted for substantially horizontal positioning when in-use, and said free end being formed to facilitate movement of a contactor of suitable form into engagement therewith.

10.'In an electric snap switch of the tool handle type, in combination, a molded insulating base having a recess opening to the upper surface thereof, a plurality of sets of stationary and movable contacts located within said recess,

actuating means for said movable contacts comprising a substantially U-shaped metal yoke pivotally supported above said recess and ex; tending downwardly thereinto, a fiat punched plate of insulating material pivotally supported by said yoke and movable in a plane parallel to the plane of movement of the latter, an operating lever pivotally supported above said yoke, a coiled compression spring interposed between the lower end of said lever and said yoke, an

approximately cylindrical springguide member telescoped downwardlyover said coiled compression spring and extending throughout the major portion of the length of the latter, said guide member having a concave upper end to provide an abutment for said lower end of the lever, said guide member having a diametrically opposed 11. In an electric snap switch of the tool T handle type, in combination, a molded insulating base having a recess opening to the upper surface thereof, a plurality of sets of stationary and movable contacts located within said re-' cess, actuating means for said movable contacts comprising a substantially U-shaped metal yoke pivotally supported above said recess and extending downwardly thereinto, a flat punched plate of insulating material pivotally supported by said yoke and movable in a plane parallel to the plane of movement of the latter, an operating lever pivotally supported above said yoke, a

coiled compression spring interposed between the lower end of said lever and said yoke, an approximately cylindrical spring guide member telescoped downwardly over said coiled compression spring and extending throughout the major portion of the length ofthe latter, said guide member having a concave upper endto provide an abutment for said lower end of the lever, said guide member having a diametrically opposed pair of slots extending throughout the' length thereof, said slots normally providing clearance between said member and the arms of said yoke, the opposed walls of each slot cooperating with the respective yoke arms to re-' strain said member against substantial rotary displacement, said member having at its lowerend a diametrically opposed pair of relatively short upwardly extending notches to provide clearance between said member and said insulating plate upon relative oscillatory movement between the former and the latter, said notches being arranged at substantially right angles to a line through said slots, each of said stationary contacts being resilient and having an inverted J-shaped wiring terminal portion formed integrally therewith, the upper end of said wiring terminal portion being adapted for interlocking engagement with said base in a plane substantially flush with the upper surface of the latter, said wiring terminal portion having an opening formed therein, 'a binding screw the shank of which is freely insertable through said opening, and a relativelyrigid metal plate positioned at the inner surface of said wiring terminal portion and having an opening with which said screw shank has threaded engagement, to provide for clamping of a wire end between the head of said screw and said wiring terminal portion, and said base and said stationary contacts being formed to provide clearance for the respective shanks of said binding screws.

12. As an article of manufacture, a guard for the coiled compression spring of a snap switch of the tool handle type, said guard being stamped to substantially cylindrical form from a relatively long metal strip having arcuate notches formed in opposite ends thereof, the sides of said strip when formed providing diametrically opposed slots extending throughout the entire length of the guard which slots afford operating clearance between said guard and a pivoted yoke member of suitable form, said arcuate notches being diametrically opposed, at substantially right angles to said slots, to provide oscillatory clearance between said guard and an insulating plate pivotally supported by said yoke,

. and the upper end of said guard being of concave form to provide an abutment for the lower end of an operating lever of suitable form. 13. As an article of manufacture, a sheet metal spring guard for electric snap switches of the tool handle type, said guard being of substantially cylindrical form and the same being of a,

lengthat least as great as the diameter thereof, said guard being formed from a metal strip of a width less than said diameter, to thereby provide a pair of diametrically opposed slots extending throughout the length of said guard, for the purpose set forth, said guard being provided at its lower end with a diametrically opposed pair of arcuate notches arranged at substantially right angles to said slots, for the purpose set forth, and the upper end ofsaid guard being of concave form to provide an abutment for an operating member of suitable form.

14. In an electric switch, in combination, an insulating base adapted to be produced by a straight-line molding operation, said base having a substantially rectangular recess, formed therein and opening to the upper surface thereof, an end wall of said recess having a groove extending throughout the major portion of the depth of the latter and opening to the upper surface of said base, said end wall'having an integral endwise extension alined with and below said groove but of greater width than the latter, said extension having an upwardly opening pocket formed therein. the opposite walls of said groove having alined inverted L-shaped recesses formed therein and opening to the upper surface of said base, a one-piece combined stationary contact and wiring terminal member .havinga relatively wide terminal portion bent to substantially inverted J-shape in cross section, the hooked end of said J being adapted for interlocking engagement with the walls of said inverted L-shaped recesses in a plane substantially flush with the upper surface of said base, the lower end of the long arm of said J being adapted to fit within said pocket, and a binding screwassociated with said long arm of said J and adapted to clamp a circuit wirev in engagement with the latter, said base cooperating with said terminal portion of said member to resist distortion or displacement of the latter in the event of a pull or strain upon said circuit wires 15. In an electric' switch, in combination an insulating base, said. base having a relatively deeprecess formed in the upper surface thereof,

said base having an upwardly opening groove formed in an end wall of said recess, said end wall of the recess having a pair of relatively small alined grooves formed therein and open- .ing to the upper surface of said base, a one-piece combined contact and terminal member having a resilient contact portion thereof located within said recess and a terminal portion one end of which is located exteriorly of said recess, the upper end of said terminal portion extending inwardly in a plane substantially flush with the upper surface of said base and then downwardly into said relatively small alined grooves, a binding screw associated with said terminal portion and adapted to clamp a conductor wire to the latter, said first mentioned groove being adapted to accommodate the shank of said binding screw,

and an insulating plate rigidly secured to the upper surface of said .base and adapted to secure said combined contact and terminal member in assembled relation to said base.

16. In an electric switch, in combination, an insulating base, said base having a relatively deep recess formed in the upper surface thereof, said base having an upwardly opening groove formed in an end wall of said recess, said end wall of the recess having a pair of relatively small alined grooves formed therein and open-.

ing to the upper surface of said base, a one-piece combined contact and terminal member having a resilient contact portion thereof located within said recess and a terminal portion one end of which is located exteriorly of said recess, the upper end .of said terminal portion extending inwardly in a plane substantially flush with the upper surface of said base and then downwardly into said relatively small alined grooves, a bind-- ing screw associated with said terminal portion and adapted to clamp a conductor wire to the latter, said first mentioned groove being adapted to accommodate the shank of said binding screw, an insulating plate rigidly secured to the upper surface of said base and adapted to secure said combined contact and terminal member in assembled relation to said base, and a metal plate interposed between said terminal portion and the outer surface of the end wall of said recess, said metal plate having a tapped openingv for threaded engagement by the shank of said binding screw.

. GEORGE J. MEUER.

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