US2585824A - Electric switch - Google Patents

Description

Feb. 12, 1952 E. E. NoYl-:s 2,585,824

ELECTRIC SWITCH Filed Jan. 27, 1948 "l I x l Vl I INVENTOR.

I 1 fl/fRETT E. No vi BY 24 voga/WM Patented Feb. 12, 1952 ELECTRIC SWITCH Everett E. Noyes, Warrensville, Ohio, assignor to The Electric Controller & Manufacturing Company, Cleveland, Ohio, a corporation of Ohio Application January 27, 1948, Serial No. 4,569

20 Claims. 1

This invention relates to electric switches and more particularly to auxiliary or control circuit switches for use on electromagnetic ccntactors.

Electromagnetic contactors having main contacts which carry the load current of the translating device being controlled are often provided with one or more auxiliary or control circuit switches. The auxiliary switches, which may have either normally-open or normally-closei contacts or both, are interposed in the control circuits of the controller comprising the ccntactor or in the control circuits of a related controller and generally serve an interlocking function to insure a desired sequence of contactor operation. Since the proper and safe operation of a complete control installation is dependent upon the ability of the control circuit switches to function repeatedly in a reliable and accurate manner, they must be rugged enough to withstand for long periods of time the mechanical and electrical abuse to which they are often subjected. On the other hand, the control circuit switches must be of limited size and require but a small amount of power for operation in order to maintain the overall size of the contactor within reasonable limits. Furthermore, the wearing parts of the control circuit switches should be easy to remove and replace and but a few different types of parts should be required for switches usable on many different sizes of both normallyopen and normally-closed contactors.

It is the object of the present invention to provide an improved control circuit switch meeting all of the foregoing requirements.

Other objects are to provide an improved control circuit switch for use on electromagnetic contactors which requires no adjustment, has nonhorizontal contact surfaces, has both normally open and normally-closed double-break contacts, and is so arranged that its various parts may be easily removed and replaced.

Another object is to provide an improved bridge-type control circuit switch in which the movable normally-closed and normally-open contact bridges are completely insulated from each other.

An additional object is to provide a control circuit switch which has but two different types of contact elements although it may have both normally-.opcn and normally-closed contacts and is usable interchangeably on both normally-open and normally-closed contactors of widely varying sizes and interrupting capacities.

The switch of this invention comprises in its preferred form an insulating bracket arranged for attachment to the rockable armature of a clapper-type contactor and carrying within a continuously walled opening therein a pair of identical conducting contact bridges biased apart by a helical spring and insulated from each other by insulating members interposed between the spring and the respective contact bridges. The insulating members also serve to releasably retain the spring and bridges in cooperative relation within the opening. Each of the Contact bridges carries a pair of spaced contact buttons which, -upon rocking movement of the armature, engage and disengage complementary stationary Contact buttons. Each of the stationary contact buttons is carried by a contact bracket detachably mounted on a stud. All of the stationary contact brackets are identical whereas the studs, which extend outwardly from the supporting structure for the contactor, may be of various lengths dependingvupon the size and type of contactor and whether the contact button associated with the stud is to be in normally-open or normally-closed position with respect to its complementary movable contact button. Each of the stationary coni tact ybrackets has contact buttons on opposite faces thereof, respectively, which are selectively placed into operative position vdepending upon whether the bracket is mounted on a stud which positions it for normally-open or normally-dosed operation 0f its operative contact. rlihe life of each of the stationary contact brackets is thereby doubled, merely by changing its position from one stud to another.

Further objects and advantages of this inven tion will become apparent from the following de scription wherein reference is made to the drawings in which:

Fig. 1 is a, side elevation of the improved control circuit switch mounted on the armature of a normally-open electromagnetic contactor;

Fig. 2 is a front elevation of the switch of Fig. l;

Fig. 3 is an exploded View and Fig. 4 is a side elevation of the movable contact assembly;

Fig. 5 is a sectional view taken along the line 5-.5 of Fig. 4;

Fig. 6 is a side elevation of the switch or" Fig. i mounted on a normally-closed contactor; and

Fig.. 7 is a side elevation of a modiiied station=u ary contact assembly.

Referring to Figs. l and 2, an armature assembly I which may be part of a normally-open electromagnetic contactor of the type, for example, described in L. A.A Troimov Patent No. 2,071,595 is suitably mounted for limited rotary or rocking movement by having spaced bearing portions l l rotatably received on opposing end portions of a shaft i 2 carried by a supporting bracket I4 accurately positioned on and secured to an insulating panel l5 as by a pair of horizontally spaced cap screws l5. The armature IU may carry the movable element of one or more normally-open main circuit contacts lil. Upon energization of a winding Il, the armature IB rotates counter-clockwise (as viewed in Fig. l) from the normal or open position in which shown into engagement with a magnetic core cap I3 thus to close the main contacts, and upon deenergizaticn of the winding il returns as by gravity to its initial position where it is stopped by engagement of shouldered surfaces i9 and 20 formed on the armature I3 and on the support i4, respectively. The core cap i3 is maintained in a well-known manner a definite distance from the panel i5 and the surfaces I9 and 2i) may be finished or otherwise accurately determined whereby the opposite limits of movement of the armature i are accurately fixed.

The control circuit switch of this invention is adapted to be operated by such movement of an armature member to open and close gaps in the control circuits of a controller comprising the contactor or of a related controller. The movable assembly of the control circuit switch comprises a contact carrier 2l preferably molded from suitable insulating material such as Bakelite and, as shown has a continuously walled transverse opening 22 formed in an enlarged end portion thereof. The reduced other end portion of the carrier 2l has opposing parallel surfaces 23 and 24 which, in the embodiment shown, are normal to the planes of opposing side walls 25a and 2519 (Fig. 3) of the opening 22 and parallel to opposing end wall surfaces 26 of the opening. rlhe side wall surface 25d of the opening 22 thus may be considered an end wall of the carrier 2l that terminates at overhanging end wall surfaces 2li of the opening. Preferably, the opening l22 is continuously walled, as shown, thus eliminating any possibility of breakage of the overhanging portions that define the end walls. The surface 24 is preferably a coplanar extension of one surface of the enlarged end portion whereas the surface 23 is displaced from the plane of the opposite surface of the enlarged end portion by an angularly disposed surface 21. The carrier 2l is secured as by screws 28 to a projection 29 formed on the armature lil and has its surface 23 in face-to-face contact with an inwardly extending and downwardly directed finished surface 30 of the projection 23. As shown in Fig. 2, the armature lli may have a projection 29 on each side whereby two identical control circuit switches may be accommodated on a single contactor if desired.

The shaft l2 is accurately mounted in the support I4 which in turn is accurately positioned on the panel l and thus the armature IU is constrained to move in an accurately predetermined and consistently maintained path relative to the panel l5. Since the extent of movement of the armature I3 is limited by the fixed position of the core cap I8 and the shouldered surface 2li and since the surface 23 of the carrier 2l is accurately positioned on the finished surface 30 of the projection 29, the opening 22 swings in an arc denitely predetermined in length as well as in position with respect to the panel l5. As will become apparent, the accuracy of the length and location of this arc permits the elimination of adjustment features 4 heretofore generally provided in switches of this type.

As shown most clearly in Fig. 3, a pair of identical Contact bridges 32, a pair of identical retainer members 34, and a helical spring 35 are adapted to be received in the opening 22. Each of the contact bridges 32 preferably comprises a flat strip cut from suitable electrical conducting strip stock, such as copper, of rectangular crosssection and each has a central opening 3B and a pair of suitable contact buttons 38 preferably of silver alloy welded or otherwise secured in axial alignment with each other on opposite faces. respectively. Each of the contact buttons 38 has a peripheral side wall or edge which, in the illustrated embodiment, is of circular configuration, and, considering each pair of the contact buttons 38 on the same face of the bridges 32, the portions of the peripheral side walls thereof which face each other constitute shoulder areas which are spaced apart endwise of the bridge from, and face toward, each other.

The retainer members 34 are releasably engageable with the spring 35 and the carrier 2| and constrain the contact bridges 32 and the spring in operative position within the opening 22. Each of the retainer members 34, which are preferably molded from suitable insulating material, has a central portion 39 of reduced width defining a pair of opposing open slots 40. The slots 43 are intermediate of respective pairs of terminal tab portions 4| each of which has a. side wall 42 constituting a shoulder area and defining an end of the adjacent slot. A cylindrical boss 44 and a cylindrical boss 45 of lesser diameter are formed in axial alignment on opposing sides, respectively, of the central portion 39 of each of the retainers 34.

The movable portion of the switch is assembled by inserting a pair of the retainers 34 into the opening 22 and then rotating them until the respective bosses 44 are directed toward each other. The width of the central portion'39 is slightly less than the distance between the side walls 25a and 25h and the length of the slots 40 is slightly longer than the distance between the side surfaces of the carrier 2l so that each of the retainer members 34 may slide freely toward and away from each other within the opening 22 while being releasably held therein by engagement of the walls 42 with adjacent opposing side surfaces of the carrier 2l near the opening 22, With the retainers 34 disposed within the opening 22, the spring 35 may be compressed and inserted between the retainers 34 and then released to permit the respective bosses 44 to enter loosely into opposing end portions of the spring 35. The peripheral side wall of each of the bosses 44 thereby constitutes a shoulder area which releasably engages the spring 35 and constrains the spring 35 in its operative position. Expansion of the spring 35 forces the retainers 34 against the opposite end walls 25 of the opening 22, respectively.

By again compressing the spring 35, the upper one of the contact bridges 32 may be inserted into the opening 22 between the top wall 26 and the uppermost retainer 34. When the opening 36 of this bridge is aligned with the boss 45, release of the spring causes the boss 45 to enter the opening 36, which in effect provides aligned recesses in opposite faces of the bridge for receiving the boss 45, whereby the upper bridge 32 is releasably held with opposite end portions thereof extending outwardly from opposite sides of the carrier 2l. The lower one of the contact bridges 32 may likewise be inserted into the opening 22 between the bottom wall l25 and the lowermost retainer 34 the boss 45 of which enters the opening 3G in the lower bridge when the lower bridge is properlyl positioned and the spring 35 released, The width of the contact bridges 32 issuiiiciently less than the width of the opening 22 between the side walls 25 to permit the bridges to slide freely toward and away from each other, but these two dimensions are so related that the bridges are restrained from any extensive rotary movement about the common axis of the bosses '45. Thus the opposite side walls of each boss 45 provide shoulder areas which are spaced apart endwise of the retainer 34, and the opposite side Walls of each opening 36 provide shoulder areas engageable therewith for constraining relative movement of each bridge 32 and its associated retainer 34. As best illustrated in Fig. 5, when the uppermost bridge 32 is in operative position, the shoulder areas which, in the form illustrated, are dened by the inner portions of the peripheral side walls of the contact buttons 3S on the under face of the uppermost bridge 32 are positioned for engagement with complementary shoulder' areas defined by the opposite wall surfaces, respectively, of the uppermost retainer 34, and when the lowermost bridge 32 is in operative position, the shoulder areas defined by the inner portions of the peripheral side walls of the contact buttons 38 on the upper face of the lowermost bridge 32 are positioned for engagement with complementary shoulder areas defined by the opposite wall surfaces, respectively, of the lowermost retainer. Thus each retainer and its associated bridge are constrained by shoulder areas from relative movement endwise of the bridges out of operating position. Accordingly each of the retainers 3c serves to transmit the biasing force of the spring 35 to its associated one of the bridges 32, is constrained from movement out of the opening 22 by engagement of its walls 42 with the side walls of the carrier 2|, constrains its associated one of the bridges 32 from movement out of the opening 22 by engagement between its end walls and the shoulder areas dened by a pair of the contacts 38 on that bridge, and constrains the spring 35 from movement out of the opening 22 by engagement between its boss il and the spring. Preferably the length of the bosses 45 is approximately the same as the thickness of the bridges 32 so that the tension of the spring 3'5 is approximately the same whether one or two of the bridges are in operative position.

The stationary contact portion of the control circuit switch comprises a plurality of identical contact brackets 54 preferably formed of suitable electrical conducting strip stock, such as copper, of rectangular cross section. A lower end portion 55 (as viewed in Fig. 1) of each of the brackets 54 is bent at a right angle to an intermediate portion 53 to denne an upwardly directed flat surface 5l', and the other or upper end portion 58 is bent at a lesser angle, preferably about forty-ve degrees, away from the intermediate portion 5B in the opposite direction. A pair of suitable contact buttons 59 which may be the same as the buttons 38 are welded or otherwise secured in axial alignment with each other on opposite faces, respectively, of the portion 58 near the upper extremity thereof.

A pair of supporting studs 60 each for holding one of the contact brackets 54 are suitably mounted in horizontal spaced relation on the panel l5. As shown, each of the studs has an inner reduced portion 3l received into a complementary opening 62 in the panel and has an annular shoulder 64, defined by the junction of the reduced portion 3| and an enlarged cylindrical portion e5, in engagement with the front surface of the panel. An inner end portion of each of the studs E0 may be threaded to receive a retaining nut 65 and a conductor holding nut et. An outer end portion 69 of each of the studs et is of non-circular cross-section, preferably square, and defines a downwardly directed flat surface 'lil normal to an end face 1I. One of the contact brackets 54 is secured to the end face 1l of each of the studs 60 as by a screw 73 with the surface 5l engaging the surface 18.

In like manner a pair of supporting studs T2 are mounted in horizontal spaced relation on the panel l5 above the studs 60 by insertion of reduced portions 'f4 thereof into respective spaced openings 35. The studs l2 are preferably identical with the studs 60 except that intermediate enlarged cylindrical portions 'F6 of the studs 12 are shorter than the corresponding portions 65 of the studs 6). An annular shoulder 11 on each of the studs 'l2 is held tightly against the panel i5 by a nut le threaded on an inner end portion of the studs and each of the studs 12 has a downwardly directed flat surface i9 on an outer end portion B3 of non-circular cross-section. The stud portions 55 and i6 are preferably cylindrical, as shown, so as to prevent the piling of dust thereon which may cause short circuits.

By positioning the pairs of openings 62 and 15 accurately with respect to the support I4, accurately determining the exposed lengths of studs 53 and l2, and by making the brackets 54 uniform, all the contact buttons 59 are in predetermined positions along the are of movement of the contact buttons 38 and have their respective axes substantially tangential with respect to the arc of movement, thus rendering adjustment of the control circuit switch unnecessary.

When the armature I() is in its normal position as shown, the upwardly directed contacts 38 on the upper contact bridge 32 are in engagement with respective downwardly directed contacts 59 on the upper brackets 54 and the upper bridge 32 has been displaced from its normal position to the extent indicated (see broken Yline position, Fig. 4) against the bias of the spring 35 which maintains a definite contact pressure. A circuit is thus completed between the spaced studs 'I2 through the upper contact bridge 32. When this circuit is completed, the angular relationship of the carrier 2! with respect to the portions 58 of the upper brackets 54 is such that the upper bridge 32 is turned slightly about its longitudinal axis with the engaged contacts 38 and 59 slightly out of axial alignment. When the winding I1 is energized to move the armature l0 to its closed position, the carrier 2i swings downwardly about the axis of the shaft i2 to cause engagement of the downwardly directed contacts 38 on the lower bridge 32 with respective complementary upwardly directed contacts 59 on the lower brackets 53. This completes a circuit between the studs 6c through the lower bridge 32. Prior to engagement of the contacts 38 of the lower bridge 32 with the respective contacts 59 on the lower brackets 54, the outer surfaces of the contacts 38 and 59- lie in parallel planes. After engagement of these contacts and while the spring 35 is being compressed, the lower contact bridge 32 rotates slightly about its longitudinal axis in a counter-clockwise direction as viewed in Fig. 1. Thus a rolling engagement of the contact faces is obtained which improves their current carrying ability by removing any deposits on the contact surface and bringing the surfaces into close relationship. A similar rolling action of the contact faces of the upper normally-closed contacts is obtained when the armature I returns to its normal position.

It should be noted that the contact brackets 54 may be used interchangeably in normally open or normally-closed position depending upon the position and length of the associated studs, and that when interchanged diiferent ones of the contact buttons 59 are placed into operative position.

The insulating retainers 34 prevent any possibility of a circuit being completed from a lower stud 50 to an upper stud 'l2 of opposite polarity through an arc drawn between separating contacts. Thus, in addition to serving as retainers for the bridges 32 and the spring 35, the retainers 34 permit the stationary contact studs to be connected at either polarity indiscriminately.

From the foregoing it is apparent that there is provided a control circuit switch of small and compact design yet one rugged enough to withstand severe service. Because of the provision of the opening 22, instead of an open slot, the bracket 2| has no reduced cross-sectional areas subjected to excessive strain.

The contact bridges may be easily removed and replaced from the front of the contactor without the use of tools, and the brackets 54 and carrier 2| are easily removed and replaced by the manipulation of screws the slotted heads of which face the front of the contacter. If only one contact bridge 32 is required, the other may be removed without impairing the operation. This is because the boss 4'5 which normally would enter the opening 36 in the removed bridge bears against the adjacent end wall 26 of the opening 22 thereby maintaining the proper length of the spring 35.

In Fig. 6, the control circuit switch is shown as used on a normally-closed contactor having an armature 82 mounted for limited rotary movement about a shaft 83 carried by a bracket 84 secured to a panel 85. carry the movable element of one or more normally-closed main circuit contacts (not shown). Upon energization of a winding 86, the armature 82 rotates clockwise from the normal or closed position in which shown into engagement with a magnetic core cap 8l thus to open main contacts (not shown), and upon deenergization of the winding 86 returns as by the force of a spring (not shown) to its initial position against a suitable stop 89.

The armature 82 is provided with a projection 90 having an inclined finished Surface 9|. The carrier 2| of the movable contact assembly is secured to the projection 90 with its surface 24 in face-to-face contact with the surface 9| and the contacts 38 thereof swing in a predetermined arc upon rocking action of the arma-ture 82. Pairs of horizontally spaced upper studs 92 and lower studs 94 are carried by the panel 85 and each of these studs receives on its outer end one of the contact brackets 54. In Fig. 6, each of the brackets 54 is inverted from the position in which shown in Figs. 1 and 2 with its flat surface portion 51 engaging a iiat surface 95 formed The armature 82 may r on the upper side of the outer end portion of each of the studs 92 and 94.

When the armature 82 is in normal position, the lower contact bridge 32 as viewed in Fig. 6 completes a circuit between the studs 94 and, upon energization of the winding 86, this circuit is interrupted anda circuit completed between the upper studs 92 through the other one of the contact bridges 32. Interchanging the contact brackets 54 between upper and lower studs puts different ones of the contact buttons 59 into operative position.

In the modified stationary contact assembly of Fig. 7, a plurality of identical contact brackets |0| similar to the brackets 54l are suitably mounted in spaced relation on the outer ends of suitable studs |02, respectively, al1 of which are of the same length. A pair of contact buttons |04 similar to the buttons 59 are secured on opposite faces, respectively, of the outer end portion of each of the brackets |0| and are displaced axially from each other longitudinally of their respective brackets. When a pair of the brackets |0| are in mounted position on vertically aligned studs |02, respectively, as viewed in Fig. 7, the inner contact button |04 on the uppermost bracket |0| is spaced from and faces the outer contact button on the lowermost bracket. Upon interchanging the positions of lowermost and uppermost brackets |0|, the outer contact button |04 on the bracket |0| that before the interchange was the uppermost now faces the inner contact button on the bracket that before the interchange was the lowermost. By proper selection of the angle of bend of the brackets |0| and the positions of the contact buttons |04, the respective axes of those contact buttons |04 which face each other may be made substantially tangent to an arc defined by swinging movement of the movable contact buttons 38 carried by the carrier 2|.

Having thus described my invention, I claim:

1. An electric switch comprising a contact carrier having a guide wall surface and spaced overhanging wall surfaces extending outwardly in face-to-face spaced relation with each other from opposite end portions, respectively, of the guide wall surface, a conducting contact bridge received in the space between the overhanging wall surfaces and having opposite end portions extending outwardly beyond the opposite edges of the guide wall surface, said contact bridge slidably engaging said guide wall surface for free movement there along in a path toward and away from said overhanging wall surfaces while being constrained by said guide wall surface from extensive rotary motion about an axis normal to said overhanging wall surfaces, a spring between the overhanging wall surfaces for normally biasing said contact bridge against one of said overhanging wall surfaces, a member movable along said path and interposed between said spring and said bridge and transmitting the biasing force of the spring to the bridge, means on the member detachably engageable with the carrier for constraining said member in said path, and said member and contact bridge having mutually detachably engageable portions which constrain said contact bridge in operative position in said path.

2. An electric switch as in claim 1 characterized in that said member is of insulating material and said spring is of electrically conductive material.

3. An electric switch comprising a contact carrier provided with a vcontinuous walled opening having elongated parallel'side wall surfaces and opposing end wall surfaces, -a conducting contact bridge received in said openingV with opposite end portions extending'outwardlyY from said opening on opposite sides of said carrier, said contact bridge slidably engaging said side wall surfaces in a path for movementl along said side Wall surfaces toward and away from saidend wall surfaces while being constrained by said side Wall surfaces from extensive rotary motion about an axis normal to said end wallsurfaces, a spring between said end wall surfaces for normally biasing said contact bridge against one of said end wall surfaces, a member movable along said path and interposed between said spring and said bridge and transmitting-the biasing force of the spring to the bridge, means on the member detachably engageable with the carrier for constraining said memberV from movement out of said opening, and said member and contact bridge having mutually detachably engageable portions which constrain -saidcontact bridge in said path.

4. An electric switch according to claim 2 having elongated parallel side wall surfaces and opposing end wall surfaces, a conducting contact bridge having an aperture and received in said opening with opposite end portions extending outwardly from said opening on opposite sides of said carrier, said contact bridge slidably engaging said side wall surfaces for free movement along said side wall surfaces toward and away from said end wall vsurfaces while being restrained by said side wall'surfacesfrcm extensive rotary motion about an axis normal to said end wall surfaces', a helical spring within said opening normally biasing saidv contact bridge against one of said end wall surfaces, a retainer member releasably held in said opening intermediate of said contact bridge and said spring and having opposing bosses received respectively within the helix of said spring and 'in said aperture, whereby said contact bridge and said spring are releasably constrained against displacement from said opening.

6. The electric switch of claim 5`characterized in that a second retainer member is releasably held in said opening intermediate of the other one of said end wall surfaces andl said spring, said retainer members being identical and one of the bosses on said second retainenbeing received within the helix of said spring, and the other one of the bosses of said'second retainer and the boss of said rst named retainerin said aperture each having an axial length relative to the thickness of said contact bridge such that upon insertion of a second identical contact bridge in said opening with said otherone of the bosses of said second retainer received 1in' the aperture of the identical bridge, the tension of said spring remains substantially unchanged.

7. The electric switch ofclaim 6character ized in that said second contact bridge is inserted between said Second retainermember and said other one of said end wall surfaces with said other one of the bosses of said secondretainer received in the aperture of the second bridge, and said retainer members are of insulating material and electrically insulate said contact bridges, r-e- Spectively, from said spring and from each other.

8'. An electric vswitch comprising ra pair of identical rigid contact brackets Aeach" having' a pair of' contact buttons, said buttons of each bracket being secured on opposite sides .thereof respectively, means detachably holding said brackets in xed spaced relation with one of the contact buttons on one of the brackets spaced from andfacing one of the contact buttons on the other one of the brackets, and said other contact buttons being so positioned on their respective brackets that, upon interchanging the position of the two brackets, the other button'of each bracket interchanges position with said one button of the other bracket.

9. The 'switch` of' claim 8 vcharacterized-in that the contact buttons of each bracket are disposed in axial alignmentr with each other.`

10. An electric switch comprising a movable contact means movable along a xed Vpath beltween limits, a pair of identicall contact brackets each having a pair of contact buttons, said. but'- tons of each bracket being secured on opposite sides thereof respectively, means detachably holding said brackets in spaced xed relationwith one contact button on one of the brackets` facingY one of the contact buttons on the other one of the brackets with the facing contact buttons .disposed at said limits respectively of said path of movement, and saidother contact buttons being so positioned upon their respective brackets that they face each other at said limits respectively upon interchanging the positions ofA said brackets.

11. An electric switch comprising a movable contact means movable along a xed path be-v tween limits, a pair of identical contactbrackets each having, endwise of the bracket, an innermost and an outermost contact button, said contact buttons being secured on opposite sides respectively, of their respective brackets, andY means detachably holding said brackets in spaced xed relation with the innermost contact button on one of the brackets facing the Voutermost contact button on the other one of the brackets `with the facing contact buttons disposed at said limits respectively of said path of movement, whereby said other contact button of each bracket interchanges position with said one button of the other bracket upon interchanging thepositions of said brackets.

12. An. electric switch comprising a pair of identical contact brackets each having a pair of contact buttons, said buttons of each bracket being secured on opposite sides thereof respectively, means detachably holding said brackets in spaced relation with one of the contact buttons on one of the brackets spaced from and facing one of the contact buttons on the other one of the rackets and with the respective axes of the facing contact buttons approximately tangent to a common circular arc at predetermined spaced points respectively on said arc, and said other contact buttons being so positioned upon their respective brackets that, upon interchanging said brackets, said other contact buttons are spaced from and face each other with their respective axes approximately tangent to said arc at said predetermined points, respectively.

13. The electric switch of claim 12rcharacter ized in that said contact buttons when in'facing position have their respective axesvat an angle to the vertical.

14. An electric switch comprising a plurality of identical contact brackets each having a pair of contact buttons, said buttons of each bracket being secured on opposite sides thereof, spaced mounting means for a rst pair of said brackets, respectively, detachably holding said first pair of bracketsv in spaced relation with respect to each other with one contact button on one of said brackets of said first pair facing one contact button on the other one of said brackets of 'said first, pair approximately along a nonvertical axis, spaced mounting means for a second pair of said brackets, respectively, detachably holding said second pair of brackets in 'spaced relation with respect to each other with one contact button on one of the brackets of said second pair facing one contact button on the other of the brackets of said second pair along a second axis approximately parallel to the first axis, a movable contact means movable substantially along said axes for bridging between said one contact button on said one bracket of said first and said one bracket of said second pair of brackets, and said other contact buttons being positioned on said brackets, respectively, so that, upon interchanging brackets having contact buttons in the same axis, said other contact buttons on said brackets face each other along said last mentioned axis.

15. An electric switch comprising a plurality of identical contact brackets each having a pair of contact buttons` said buttons of each bracket secured on opposite sides thereof, spaced mounting means for a first pair of said brackets, respectively, detachably holding said first pair of brackets in spaced relation with respect to each other with one contact .button on one of said `brackets of said Vfirst pair facing one contact button on the other one of said brackets of said first pair approximately along a non-vertical axis, spaced mounting means for a second pair of said brackets, respectively, detachably holding said second pair of brackets in spaced relation with respect to each other with one contact button on one of the brackets of said second pair facingl one contact button on the other of the brackets of said second pair along a second axis approximately parallel to the first axis, a pair of conducting contact bridges each having contact end portions at opposite ends thereof, a movable contact carrier movable between and substantially parallel to said axes and defining an opening slidably receiving said contact bridges in spaced apart relation with one pair of the contact end portions extending outwardly from said opening and disposed in one of said axes in alignment with the contact buttons thereof and the other pair of contact making end portions extending outwardly from said opening and disposed in the other of said axes in alignment with the contact buttons thereof, a metal spring biasing said bridges apart, insulating retainers between said bridges respectively and said spring and shaped to hold said spring and bridges in assembled relation in said opening, and means for moving said carrier from a position wherein one of said bridges forms an electrical connection between two of said contact buttons to a position wherein the other of said contact bridges forms an electrical connection between the other contact buttons which face said two contact buttons.

V16-l An electric switch comprising a contact carrier provided with a continuous walled opening having elongated parallel side Wall surfaces and opposing end wall surfaces, a pair of conducting contact bridges received in said opening, each with opposite end portions extending outwardly from said opening on opposite sides of said carrier, said contact bridges slidably engaging said side wall surfaces for movement along said side wall surfaces toward and away from said end Wall surfaces while being restrained by said side wall surfaces from extensive rotary motion about an axis normal to said end wall surfaces, a metal spring in said opening and between said contact bridges and normally biasing said contact bridges against said end wall surfaces, respectively, insulating means interposed between said spring and said contact bridges, respectively, and each releasably engaging the spring and carrier, means on the insulating means engaging the carrier for constraining the insulating means from movement out of the opening when in normal operating positions, means on each insulating means engaging its associated contact bridge and constraining its associated contact bridge from movement out of the opening, means on the insulating means engaging the spring and constraining said spring to operative position in said opening and each of said insulating means electrically insulating its associated contact bridge from said spring.

17. An electric switch comprising a contact carrier provided with a continuous walled opening having elongated parallel side wall surfaces and opposing end wall surfaces, a pair of elongated conducting contact bridges received in said opening each with opposite end portions extending outwardly from said opening on opposite sides of said carrier and having shoulder areas spaced apart endwise of the bridge from, and facing toward, each other, said contact bridges slidably engaging said side wall surfaces for movement along said side vwall surfaces toward and away from said end wall surfaces while being restrained by said side Wall surfaces from extensive rotary motion about an axis normal to said end wall surfaces, a metal spring in said opening between said contact bridges and normally biasing said contact bridges against said end wall surfaces, respectively, and insulating retaining means interposed between said spring and said contact bridges, respectively, and having spaced shoulder areas releasably engaging said shoulder areas, respectively, of said respective contact bridges for constraining the bridges in operative position within said opening, and having shoulder areas releasably engaging the spring and constraining said spring to operative position, and having additional shoulder areas releasably engaging the carrier and constraining the insulating means from movement out of said opening.

18. Anelectric switch according to claim 17 further characterized in that said additional shoulder areas are wall surfaces of terminal tab portions on each insulating means which engage respective outer surface areas of the carrier adjacent the opposite ends of the opening,

19. An electric switch according to claim 17 characterized further in that said spring has boss receiving openings at opposite ends, respectively, and said shoulder areas engaging the spring are side wall portions of bosses on the insulating means, respectively, and are received in said boss receiving openings, respectively.

20. An electric switch comprising a contact carrier provided with a continuous walled opening having elongated parallel side Wall surfaces and opposing end wall surfaces, a pair of elon- 13 gated conducting contact bridges received in said opening each with opposite end portions extending outwardly from said opening on opposite sides of said carrier and having shoulder areas spaced apart endwise of the bridge from, and facing toward, each other, said contact bridges slidably engaging said side wall surfaces for movement along said side wall surfaces toward and away from said end Wall surfaces while being constrained by said side wall surfaces from extensive rotary motion about an axis normal to said end wall surfaces, a metal spring in said opening between said contact bridges and normally biasing said contact bridges against said end wall surfaces, respectively, and insulating retaining the insulating means from movement out of said opening.

EVERETT E. NOYES.

REFERENCES CITED The following references are of record in the le of this patent:

UNITED sTATEs PATENTS Number Name Date 1,359,866 Bijur Nov. 23, 1920 1,839,095 Goetz Dec. 29, 1931 1,854,039 Jones Apr. l2, 1932 1,925,585 Friedman Sept. 5, 1933 2,049,747 Parsons Apr. 4, 1936 2,106,581 Unwin Jan. 25, 1938 2,172,673 Eaton Sept. 12, 1939 2,269,741 Seeger Jan. 13, 1942 2,276,698 Pierce Mar. 17, 1942 2,390,344 Ayers Dec. 4, 1945

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