US2759075A - Sealing means for electric switches - Google Patents

Description

Aug. 14, 1956 H. HULTS SEALING MEANS FCR ELECTRIC SWITCHES Filed Aug. l2, 1955 ifilaire 'i States Patent O SEALING MEANS EUR ELECTRIC SWITCHES Harold W. Hults, Milwaukee, Wis., assignor to Cutler- Hammer, Inc., Milwaukee, Wis., a corporation of Delaware Application August 12, 1953, Serial No. 373,339

3 Claims. (Cl. 20G-168) This invention relates to sealing means for electric switches. It relates particularly to sealing means for actuator openings in switch casings.

A primary object of the invention is to provide effective, easily assembled and low cost sealing means for electric switches.

Another object is to provide a seal for actuator openings in switch casings which will permit easy and proper operation of the switch actuator.

Another object is to provide a compact but effective seal for actuator openings in electric switches.

Other objects and advantages of the invention will hereinafter appear.

The accompanying drawings illustrate an embodiment of the invention which will now be described, it being understood that the invention is susceptible of embodiment in other forms, and that various modiiications may be made in respect of structural details of the device illustrated without departing from the scope of the appended claims.

In the drawings, Figure l is a vertical crosssectional view of an electric switch embodying the invention, certain of the parts being shown in elevation;

Fig. 2 is a fragmentary vertical sectional view, at right angles to the view of Fig. 1, with certain portions shown in elevation; and

Fig. 3 is a cross-sectional view of a preferred form of the sealing member employed, shown in normal or relaxed condition.

Referring to the drawings, the electric switch shown includes a casing consisting of a box-like insulating base 10, a cover plate 12 overlying the top of the base 10 and a punched and stamped sheet metal switch frame 14 overlying the cover plate 12 and having portions thereof bent into clamping engagement with inwardly and upwardly angled shoulders formed in the outer surfaces of the end walls of base 10.

The switch mechanism comprises a fixed, common terminal assembly 16 secured at the mid-point of the length of the bottom wall of the base 10, iixed terminal assemblies 18 and 20 secured to the bottom wall of base on opposite sides of the common terminal assembly 16, a rocking-type bridging contactor 22, a bridging contactor operating finger 24 and an actuator 26. Each of terminal assemblies 18 and 2G includes a lug which is riveted to the underside of the bottom wall of the base 10. The rivet head is seated against the inner surface of the bottom wall of the base 10 and serves as a stationary contact tip. The common terminal assembly 16 includes a U-shaped pivot member 1.6a and a lug 16b which are electrically interconnected and secured to the upper and lower surfaces, respectively, of the bottom wall of base 10 by a rivet 16C. 'Ihe upwardly extending arms of the U-shaped member 16a are slotted to accommodate the bridging contactor 22 and to provide a double pivot for the latter; said contactor having laterally extending lugs located between said upwardly extending arms of member 16a to prevent substantial eudwise disref-v Y if placement of said contactor upon rocking or tilting thereof one of said lugs being shown at 22a in Fig. l.

The bridging contactor operating plunger 24 is slidably disposed in a recess 28 in the actuator 26. The plunger 24 is provided with a recess 30 and is biased into engagement with the bridging contactor 22 by a coiled compression spring 32. The latter is held under compression between the top of recess 28 and the bottom of recess 30.

The mounting bushing and operating mechanism for the switch includes an externally threaded bushing 40 having an axial opening 40b therethrough, an operating lever 42 which is preferably formed of metal, a pivot member 44 for the operating lever 42, a sealing member 46, and a pair of like return springs 48 and 50 of known form.

The upper central portion 14a of the switch frame 14 is offset vertically from the cover plate 12. 'I'his oifset portion is provided with an opening 52. The lower end of bushing 40 has an enlarged inside diameter and a reduced outside diameter and extends through opening 52. The relatively thin extreme lower end portion of bushing 4i? is upset radially outwardly or riveted over the lower surface of portion 14a to effect a rigid and nonrotatable connection between the bushing 40 and the switch frame 14. The operating lever 42 consists of a somewhat enlarged, generally spherical portion 54 disposed within the axial opening 40b of the bushing 40; and an operating handle portion 56 formed integrally with and extending upwardly from the spherical portion 54 and outwardly beyond the bushing 40; and an integral shank portion 58 which extends downwardly from the spherical portion 54 through opening 52 and a relatively large opening 12a in cover plate 12 and is connected at its lower end to the top of actuator 26.

The headed pivot pin 44 penetrates openings in the walls of bushing 4t) and extends through the center of the spherical portion 54 of lever 42 in a direction to provide for pivotal movement of the lever 42 in the plane of movement of bridging contactor 22; the opposite end of pin 44 being upset, as shown in Fig. 2. Return springs 48 and 50 are trapped within the offset portion 14a of switch frame 14 on opposite sides of the shank 58 and said springs respectively act individually to normally bias the lever 42 from one of its on positions toward its central, upright or off position. If desired, of course, either or both of the springs 48 and 50 may be omitted, if a momentary contact type of switch actuation is not required.

The sealing member 46 is composed of elastic, rubberlike material. It is substantially cylindrical and has an axial opening therethrough. In its relaxed state the outside diameter of member is substantially greater than the diameter of the axial opening 49h in bushing 40. The intermediate portion 46a of the axial opening in the sealing member 46 is of a shape corresponding to the middle frustum of a sphere. The dimensions of intermediate portion 4ta are substantially less than the outside dimensions of the portion 54 of lever 42.

When in assembled relation with the switch bushing and operating mechanism, the sealing member 46 is interposed between the bushing 46 and the portion 54 of lever 42. Said sealing member surrounds and hugs or elastically embraces portion 54 and the opposite end portions 46b and 46 of its outer peripheral wall are compressively engaged with a peripheral portion of the cylindrical wall of said opening 40h in bushing 40. The ends 46d and 46e of the axial opening in sealing member 46 are each enlarged in an outward direction to provide clearance between said sealing member 46 and the portions of lever 42 on opposite sides of the portion 54 of lever 42. The ends of sealing member 46 are free to alternative a relatively wide groove might be providedl inthe inner wall 40b of the bushing 40.

These structural features permit a substantial amount; of` bulging or distortion of the sealingA member 46 as theV lever is operated without material increase in theforce required to. oper-ate the lever even though the sealgreef or"V4 compression. Moreover, the sphericalportion- 541is relatively free to rotate with respect to-the sealingmemberthe lever is` operated.

I' prefer-'to formY the sealing member 46` without perforations to accommodate the pivot member 44. After the lever l2-and the sealing member 45Y are placed in assembled relationship within bushing 40, the sealing member is piercexlV as the pivot pin 44 is inserted into openings providedfor it in thelever 42 and inthe Walls of-'the bushing 40; the' piercing endy of pin 44 beingfthenl upset, as shown in Figi 2.

I` claim:

l". In an electric switch, in combination, amountingbushing member having an axial opening therethrough of cylindrical form, an operating lever having a generallyl sperical portiontdispose'dwithinA the opening in saidbushing member, a-y substantially cylindrical elastic sealing member having an outside diameter normally greater-l than'the inside diameter of the peripheral wall of said bushing opening, said elastic sealing member havingan axialopening therethrough o-fnormally smaller dimensions than the outside dimensions of the sperical portionof-y the operating lever, one of said members having formedV therein an annular peripheral` groove, said elastic sealingmember elastically embracing said sperical portion of said-V lever and extending axially of said lever the length of said spericalv portion and being compressively engaged attheouter periphery thereof and on opposite sides of-saidl annular groove bushing opening, and a pivot member extending through said' elastic sealing member and said spherical portion of the lever and about which pivot member the lever' may be pivotally movedl with respect to said. bushing.

2. In an electric switch, in combination, a mounting* bushing having. an axial opening therethrough, `an operatinglever having a generally spherical portion disposed within the opening in said bushing, a cylindrical elasticV sealing member substantially as long as the diameterof. said.' spherical portion of'the lever, said elastic sealing with the peripheral wall of said member having an outside diameter normally greater than-thediameter of said bushing opening and having an. axial opening therethrough of normally smaller dimensions than the outside dimensions of the sperical portion ofthe operating lever, said elastic sealing member elastically embracing said sperical portion of said lever and being compressively engaged at the outer periphery thereof with; the peripheral wall of said bushing opening, a

"L pivot member extending through said elastic sealing member and said: spherical portion of'thelever andraboutz which member said levermay be pivotally moved with respect to said bushing while insuring a sealed relationship therebetween,y said elastic sealing member being proing member is maintained under a relativelyl high de-` nl vided with an annular external recess between the upper and lower ends thereof, and said sealing member being free to bulge at said recess and to bulge axially of the opening in said bushing as said lever is pivotally moved relatively to said bushing.

3. In anv electric switch, in combination, a mounting bushing having an axial opening therethrough, an operating lever having a generally spherical portion disposed within the opening in said bushing, a cylindrical elastic sealing member substantially as long as the-diameter of said sperical portion of the lever, said elastic sealing member'having an outside diameter normally greater thany thediameter of said bushing opening and' having an axial opening therethrough of normally smaller dimensions than the outsidedimensions ofthe sperical portion of the operating lever, said elastic sealing member elasticall'yV embracing-said' spherical portion of said lever and'beingV compressively engaged at the outer periphery thereofl with the peripheral wall of said bushing opening, a pivot member extending through said elastic sealing member andlsaid sperical portion of the lever' and about which member'said lever may be pivotally moved `with respect to said' bushing while insuring a sealed relationship therebetween, said elastic sealing member being provided with an annular external recess between the upper and' lower ends thereof, and said spherical portion of said lever' being relatively free to rotate with respect to said sealing member as the latter isV bulged as an inci dent to pivotal movement of said lever with respect to said` bushing.

References Cited in the file of thisvpatent UNITED STATES PATENTS' 2,400,845A Stearns May 21, 19,46

2,650,964 Razdow: Sept.v 1,1953?- FOREIGN PATENTS 9,744 Great Britain Apr- 28,1904I

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