US3016440A - Electric switch - Google Patents

Description

Jan. 9, 1962 J. F. DRlEs 3,016,440

ELECTRIC SWITCH 5 Sheets-Sheet 1 Filed Aug. 6, 1959 Jan. 9, 1962 Filed Aug. 6. 1959 e/ l gg; l l lun d m, u

AW nb IHHHHHM J. F. DRIES ELECTRIC SWITCH 3 Sheets-Sheet 2 J. F. DRIES ELECTRIC SWITCH Jan. 9, 1962 3 Sheets-Sheet 3 Filed Aug. 6, 1959 United States 3,016,440 ELECTRIC SWITCH Jerome F. Dries, Hales Corners, Wis., ler-Hammer, Inc., Milwaukee, Wis., Delaware Filed Aug. 6, 1959, Ser. No. 831,965. 6 Claims. (Cl. 200-166) assigner to Cutn a corporation of This invention relates generally to electric switches and more particularly to electric switches of the auxiliary or interlocking type.

While not limited thereto, the switch of this invention aforementioned type which can be selectively adapted to provide two norm-ally open circuits, two normally closed circuits or one normally open and one normally closed circuit.

Another specic object is to provide a bridging contactor which may be assembled and disassembled with the contactor carrier without using tools.

Yet another specific object is to provide a switch of the aforedescribed character having movable contacts and stationary contacts which engage and disengage with a self-cleaning wiping action.

Other objects and advantages ofthe invention will hereinafter appear.

The accompanying drawings illustrate preferred em- I bodiments of the invention which will be hereinafter deatent scribed in detail, it being understood that the embodi.

y ments illustrated are susceptible of various modifications p without departing from the scope of the claims.

In the drawings:

FIGURE 1 is a top plan view of an electric switch constructed in accordance with my invention;

FIG. 2 is a side elevational view;

FIG. 3 is a sectional View taken along lines 3-3 of FIG.v l;

FIG. 4 is an end elevational view;

. FIG. 5 is a fragmentary, exploded isometric view showing a portion of the switch in its assembled position;

FIG. 6 is a fragmentary sectional view of the switch ,4 shown in FIG. 8; Y p A j FIG. 7 is a view to reduced scale similar to FIG. 2

but illustrating a rnodiiiedpcontact.arrangement;l and FIG. 8 is a view similarV to FIG. 7 illustrating another modied contact arrangement.

Referring to the drawings, FIGS. 1 through 8 illustrate an auxiliary switch having a generally U-shaped mount- I ing base, designated generally by numeral 10, and anoperating member comprising a movable contact carrier asl sembly designated generally by numeral 21.

The base 10 is preferably molded of an electrical insulating material and is provided with cavities and recesses to receive intertting parts of the switch structure as will be hereinafter described. As best illustrated in FIG. 4, the base 10 is provided with an end wall 11 and two ,vertically extending, integrally formed leg portions 12. As shown in FIG. l, the opposite longitudinal extremes of end wall 11 are provided with laterally opening slots 11a to receive suitable mounting fasteners (not shown) for securing base 10 to a panel or the like. As best shown in FIGS. 3 and 4; end wall 11 is further provided with a recess 11b which opens upwardly beu tween legs 12 and laterally to onel side of base 11. Re-

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' stantially rectangular recess 13a formed in its top surface, as viewed in FIGS. 2 and 4, to receive in interfitting relationship a slotted and drilled end portion 17a of a stationary contact 17. Each shoulder portion 13 has an internally threaded circular recess located centrally of the aforementioned rectangular recess 13a to receive a threaded fastener 15 to removably secure the stationary contacts 17 to the base 10 in eitherof the alternate positions shown in FIGS. 2, 7 and 8. As best seen in FIG. l, the closed inner end of recess 13a is slightly narrower than its outer open end, therefore, the slotted portion 17a of stationary contact 17 is compressed laterally as the latter is inserted longitudinally into recess 13a. This compressive force is sufficient to retain the stationary contact 17 within the recess 13a when the fasteners 16 are backed olf to assemble or disassemble a suitable wiring terminal (not shown), to the stationary contacts 17.

Each of the legs 12 is provided with a laterally opening U-shaped recess 14 extending from the sloped upper surface 12a of legs 12 to an upwardly facing end wall 12b surrounding the periphery of the aforementioned slots 11a in base 10. The recesses 14 provide clearance for the aforementioned mounting fasteners and guide the latter as they are turned down against the end wall 12b.

A pair of aligned, circular apertures 15 communicate between the innermost wall of recesses 14 and the respective inwardly facing surfaces of legs 12. The apertures 15 receive the opposite end portions of an elongated pivot pin 18 which rotatably supports the contactor assembly 21 between legs 12. As shown in FIG. 2, one end of the pivot pin 18 is provided with radial splines which have an interference fit in the surface of one of the apertures 15 to prevent'relative rotation therebetween and unintentional withdrawal of the pin.

The stationary contacts 17 have off-set, parallel end portions 17a and 1717. As best illustrated in FIG. 1, with the slotted ends 17a of the stationary contact 17 intertted in recess 13a, the opposite end portion 17b extends outwardly from base 10 at an angle which positions the arc resistant stationary contact tips 17C in alignment with the contact tips 20e carried bythe movable bridging contactors, indicated generally by numeral 20.

vAs best shown in FIGS. 3 and 5, the contact carrier assembly 21 is of a. two-piece construction wherein-a pair of symmetrical molded members 21a are secured by rivets 22 or the like in mating relationship to form a pair of like oppositely opening cavities 23 to house and removably support the bridging contactors 20.

The side wall 23a of each cavity 23 is partially de fined by a pair of oppositely arranged, semi-circular protrusions 23b extending `toward one another. A common inner wall for cavities 23 is formed by centrally located portions 24 of members 21a which have apertures 25 therethrough penetrated by the aforementioned pivot pin 18. The side Walls 23a of cavities 23 adjacent the open end of the latter-,are defined by the flat inner surfaces 26a of the longitudinally extending nibs 26. As best shown in FIG. '5, the endv walls 23e of cavities 23 are provided with arcuate guide slots 27 extending therethrough. The walls of slots 27 have centrally located notches 27a, the purpose of which will be explained hereinafter.

As shown in FIGS. 3 and 5, .the assembled contact carrier assembly 21 is provided with a tapered recess 28 opening downwardly toward the base 10. A coiled return spring 19 for the contact carrier assembly 21 is cornpressively held between the end wall 28a of recess 2S and the end wall 11C of recess 11b.

In FIG. 2 a metal operating lever 29 is illustrated as having an upwardly extending arm portion 29a and an end portion 2% compressively held in recess 30, shown in FIG. 5, formed in the mating portions 21a of `Contact carrier assembly 21. The arm portion 29a may be bent to any desired configuration and may be manually operated or may be mounted in operating relationship with a moving element of another device such as an electromagnetically operated contactor, not shown.

As sho-wn in FIG. 5, each of the bridging contactors indicated generally by thenumeral 29, comprises a generally T-shaped electrically conductive member. stem portion 20a terminates in a semi-cylindrical tang Zband has a stamped protrusion 20c formed intermediate the length thereof. The integrally formed crossarm portion 20d is provided with arc resistant contact tips 2de at its opposite extremes for engagement with the `alined contact -tips 17e on the stationary contacts 17 As shown at the right-hand portion of FIGS. 2 and 3, the movable contact tips 20e are slightly convex thereby providing a rocking action between the latter and the stationary contact tips 17e as thev tips are engaged and disengaged. This rocking action facilitates breaking occasional welds between the contact tips.

As shown in FIGS. 3 and 6 coiled contact springs 31 are compressively retained between spring plates 32 which are in turn compressed against the side wall 23a of cavity 23 and the stem 26a of the bridging contactor 2G about protrusion 29e.

FIG. 5 illustrates that each of the spring plates 32 is` provided with a pair of oppositely arranged, laterally projecting fingers 32a which slidably engage the aforementioned arcuate guide slots 27 in members 21a. It will be understood that the fingers 32a slidably interiit with the arcuate slots 27 -as spring 31 is alternately compressed and released yduring operation of the switch. The interiittin-g of finger 32a and the arcuate slots 27 prevents endwise displacement of the spring plates 32 from the cavities 23 formed in the contact carrier assembly 21. As will be understood from the right-hand portion of FIG. 3, the contact springs 31 provide pressure between contact tips 17e and 20e, by biasing the bridging contactor 20 clockwise about a fulcrum point formed by the semicircular protrusion 2312. The bias 4of contact spring 31 also maintains the semi-'circular tang 2Gb of the bridging contactor 2i) in interlocking engagement with the semi-circular protrusion 23h, thereby preventing unintentional withdrawal of the bridging contactor from the cavity 23. v

Removal of a bridging contactor 2i? is accomplished by grasping the cross arm portion 2Gb with the fingers and `compressing the contact spring 31 until the projecting fingers 32a on the spring plate 32 adjacent the bridging contactor 20 are alined with the notches 27a in the arcuuate slots 27. Pulling the bridging contactor 2d outwardly then` interlocks the fingers 32a in the notches '27a thereby maintaining the `spring 31 compressed while the bridging contactor 20 is lifted out of engagement with the semi-circular protrusion 23b and longitudinally withdrawn from the contact carrier assembly 21.

The

One obvious advantage provided by the abovedescribed cooperation of the bridging contactor 26 with other elements of the contact carrier assembly 21 is that the bridging contactor can be assembled and disassembled without the use of tools.

3, is as follows:` The contact carrier assembly21 is held in its normal position by the biasing action ofthe return spring 19; In this normal position, theright-hand pair of stationary contacts 17 aie electrically connected by the right-hand bridging contactor 20 to complete a normally closed circuit. As the switch is operated by an external force F applied to the operation lever 29, the contact carrier assembly 21 rotates in a counterclockwise direction to compress the return springv 19. The right-hand contact spring 31 continues to exert a downward bias upon the bridging contactor 20, thereby maintaining the normally closed circuit until the ste-rn 20a of the bridging contactor is forcibly engaged and lifted upwardly by the flat surface 26a `of the lower right-hand nib 26. During the period between the initial rotary movementof the contact carrier assembly 21 and the initial lifting of the bridging contactor 2%, the latter is pivoted about the semi-circular protmsion 2317 which causes the movably contact tip 26e to slide. across the stationary contact tip 17C with a wiping action. This wiping action-removes dirt lor oxidation from the cooperating contact tips as the switch is operated to insure a good electrical connection therebetween.

As the contact carrier assembly 21 is rotated past`its top center position the left-hand pair of stationary contacts 17 is electrically connected by the left-hand bridging contactor 20 to complete the normally open circuit.

After the initial engagement of the last mentioned contact tips, further rotation of the contact carrier assembly 21 separates the left-hand bridging contactor 20` from the fiat surface 26a of the lower left-hand nibs 26 and pivots the bridging contactor 20 about the semi-circular protrusion Zb causing the movable contact tips 20e to wipe across the-stationary contact tips 17e. The overtravel of the contact carrier assembly 21- provides a predetermined wear allowance for the contact tips 17C and 20e. The counterclockwise rotation of the contact carrier assembly is limited by the abutment of the lower right-hand nib 26 upon the upper surface of end wall 11 of base 10.

When the energizing force F upon the operating lever 29l is released, the biasing force of spring 19 causes the Contact carrier asse1nbly'21 to return to its aforedescribed normal position shown in FIG. 3.

An essential feature of this invention is found in the adaptabilityof the switch to selectively provide a multiplicity of different switching circuits without additional parts. This liexibility is accomplished by arranging the bridging contactors 20 and the stationary contacts 17 according to FIGS. 7 and 8 to produce various modifications of the contact arrangement shown in FIGS. 1-4.

A switch having its contacts arranged according to FIGS. 1-4 and having one normally open and one normally closed circuit may be easily modified to provide two normally open circuits according to FIG. 8 by removing the right-hand bridging contactor 20 in the manner hereinbefore described, inverting the latter, reassembling it according to FIG. 6 andinverting the right-hand pair of stationary contacts 17 according to FIGS. 6 and 8. It will be understood that to reassemble the stem 20a of the invertedV bridging contactor 20 the latter is forcibly inserted into the cavity 23 between the upper spring plate 32 and the adjacent fiat surface 26a until the tang 2Gb engages the upper semi-circular protrusion 23b in the side wall of the cavity 23. Y

The switch illustrated in FIGS. 1-4 may be similarly modified to provide two normally closed circuits according to FIG. 7 by inverting the left-hand bridging contactor 20,`

. ing either one normally open or one normally closed circuit. f

I claim:

1. In an electric switch, in combination, an insulating base comprising a generally U-shaped block having an end wall and leg portions extending perpendicularly therefrom in spacedv parallel relationship, at least one pair vof stationary contacts having a contact thereof carried on each of said leg portions, an operating member having an opening cavity outwardly opening through an end thereof and having an intermediate portion rotatably supported between said leg portions about an axis parallel to said end wall, and a contactor having a stem portion removably pivotally mounted on a wall of said operating member defining said cavity and operable to bridge said pair of stationary contacts with a wiping action in response to rotation of said operating member.

2. 'Ihe combination according to claim 1, wherein pairs of stationary contacts extend from the opposite extremes of said leg portions, said operating member is terminated at its opposite ends by symmetrically formed cavities, and each of said cavities has a contactor removably pivotally mounted therein and extending therefrom through an end of said operating member in bridging alinement with a pair of said stationary contacts, whereby the latter are bridged in a preselected sequence upon movement of said operating member to its opposite extreme rotary positions.

3. In an electric switch, in combination, an insulating base, stationary contacts mounted on said base, a switch operating member rotatably supported by said base, at least one contactor for bridging said stationary contacts mounted on said switch operating member, said stationary contacts and said contactor being mounted on said base and said switch operating member, respectively, in reversible relationship thereto to provide a plurality of selectable bridging relationship therebetween, said switch operating member having means to removably secure said contactor thereto which comprises a cavity in said switch operating member, guide means formed in opposite walls of said cavity, spring plates positioned in said cavity and having extending iingers slidably engaging said guide means, a spring compressively retained between said spring plates and biasing the latter toward opposite extremes of said guide means, detents formed intermediate the ends of said guide means for engaging said fingers upon compression of said spring, said contactor having a portion insertable into said cavity and removably retained between a wall of the latter and an adjacent spring plate by the bias of said spring, and said contactor being withdrawable from said cavity when said spring is restrained in a compressed state by the aforementioned engagement of said iingers with said detents.

4. In a contactor carrying assembly, in combination, a housing member having a cavity therein, a contactor carried by said housing member and means for resiliently and removably intertting said contactor within said cavity in reversible relationship thereto, said means comprising a concave sleeve portion of said contactor, convex projections extending from the opposite walls of said cavity, and a spring assembly biasing said stem into interftting relationship with a selected projection.

5. The combination according to claim 4, wherein said spring assembly is provided with means engageable by said housing member to restrain said spring in a compressed condition thereby facilitating removal of said contactor from said housing member.

6. In a contactor carrying assembly, in combination, a contactor housing member having a cavity opening to one end thereof and guide means communicating with said cavity, a pair of spring plates within said cavity having extending fingers slidably engaging said guide means, a spring associated with said spring plates and biasing the latter toward opposite extremes of said guile means, a notch intermediate the ends of said guide means for interitting with said fingers when said spring is compressed suiciently to aline said'ngers with said notch, contactor means having a portion insertable into said cavity between a wall of the latter and one of said spring plates and removably retained by the bias of said spring upon said spring plate, and said contactor means being withdrawable from said cavity when said spring is compressed and held by the aforedescribed interiitting of said fingers in said notch.

References Cited in the le of this patent UNITED STATES PATENTS 2,210,793 Butler Aug. 6, 1940 2,273,545 Van Valkenburg Feb. 17, 1942 2,585,824 Noyes Feb. 12, 1952 2,619,569 Savage Nov. 25, 1952 2,773,948 Pelz Dec. 11, 1956 2,859,312 Dahlgren Nov. 4, 1958

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