US 2549998 A
Description (OCR text may contain errors)
April 24, 1951 K. c. ALLISON ELECTRIC SWITCH CONSTRUCTION 2 Sheets-Sheet 1 Filed Dec. 6, 1945 INVENTOR.
Kenneth C llison.
April 24, 1951 K. c. ALLISON 2,549,998
ELECTRIC SWITCH CONSTRUCTION Filed Dec. 6, 1945 2 Sheets-Sheet 2 [NI 'ENTOR.
KannethC. llison, 4 BY Patented Apr. 24, 1951 ELECTRIC SWITCH CONSTRUCTION Kenneth 0. Allison, Crystal Lake, Ill., assignorto Grigsby-Allison Co. Inc.,- Chicago, Ill., a corporation of Illinois Application. December 6, 1945, Serial No. 633,153
This invention relates to electric switches. and particularly switches of the typewherein. contact arms which are. carried by a rotor turning with a central shaft or spindle engage selected pairs of axially opposed contactsv which are circularly arranged on. a stationar member such as. in switches applicable forcontrolling wirelessreceiving apparatus.
One object of the invention, is the provision of a novel and improved. construction. of a switch foruse in small radios, small consoles, portable radios, table models, and the like, wherein the useof a. compact, relatively small dimensioned switch is especially desirable.
A further object of this invention is a novel and improved switch of the type referred to which is characterized by its simplicity in. construction and assemblyand they economy with which it may be manufactured in quantity pro duction.
Other. objects and advantages. of. the invention will become apparent from the following. detailed descriptiontaken in connection withthe accompanying drawings, in which:
Fig. 1 is a rear view of a switch embodying the present invention.
Fig. 2 is a side. elevationalview thereof.
Fig. 3 is a front view of the stationary member forming the rear wall of the switch.
Fig. 4 is an enlarged fragmentary vertical section taken on line 4'4 of'Fig. 1.
Figs. 5 and 6' are rear views of the switch assembly' with the stationary member and rotor removed to illustrate. details of construction and arrangement of components defining a fixed index through which the rotated, position ofthe rotoriscontrolled.
Figs. 7 and 8. and 9 are enlarged detail views of the rotor contact arms when in operatively supported position on the rotor member.
Fig. 10 is an enlarged detail view of the rotor contact member while in the process of attachment to the rotor member.
Fig. 11 and Fig. 12 illustrate a method of fastening the stationar contact members to the stationary member.
Fig; 13 is a detailed view of an opening for the reception of the contact member beforev the latter is fastened to the stationar contact member as indicated in Figs. 11 and 12..
Figs; 14 and 15 illustrate a switch of the type contemplated by this invention but embodying a housing of modified. form.
Fig. 16 is a front view of the rotor member with one of the contact arms removed to show details of one of the contact arm holding recesses.
6 Claims. (Cl. 200'-11) Fig. 17 is a side elevational view similar to Fig. 2 but taken on a. transverse plane.
Referring to the drawing, the present switch includes a central driving shaft or spindle I0 having a forward portion H adapted to project through an opening in a suitable panel (not shown) and. arranged to carry a suitable operating knob (not shown). The inner or rear end of the shaft I0 is formed with flattened sides 12.
The switch housing or frame member constitutes a front plate l3; An externally threaded bushing I4 staked as at 15 to the edges of a central opening in the plate l3 provides a bearing in which the shaft 10 may rotate. The bushing I 4 is formed with a hexagonal head l6 having opposite flattened edges thereof in abutment with the offset edge portions of'the plate opening as at I! to secure the bushing and plate against relative movement. An annular groove 18 formed in the shaft H1 is adapted to contain a lock washer I9 which coacts with the forward edge of the bushing to limit movement of the shaft I0 axially rearward of a, selected position as shown in Fig. 4. Withdrawal of the shaft I0 from this position is controlled by a spring disk-shaped member 20 staked as at 21 to the shaft. The member 20 is formed with a forward projection 22 which rides over detents 23 projecting from the rear surface of the plate I3 in a manner to index or locate the rotated positions of the shaft l3 and the contact carrying members more specifically described hereinafter. A pair of stops 24 and 25 struck up from the front plate 13 in the path of rotation of the spring member 20 selectively engagea tail 26 on the member 20 to limit the arc of movement of the shaft [0.
The-front plate I3 is provided with diametrically opposed rearwardly extending legs 21. A reduced rear end portion 28 on each of said legs is adapted to be passed through apertures formed at diametrically opposite sides of a circular stationary member or plate 30 formed of suitable material such as laminated paper base phenolic resin sheet. A shoulder 3| formed at the base or inner-limits of the reduced end portion of each leg 21 of the plate i3 cooperates with the front side of the plate 30 at the leg receiving openings so as to maintain the plate 30 in fixed axially spaced position relative to plate 13.
The plate 30 is punched to provide a series of circularly spacedopenings 32 near the outer periphery thereof. Each of the openings 32 is adapted to be fitted with a contact member 33 of'L-shaped design. One leg of each member 33 is offset intermediate its length to form a shoulder as at 34 adapted to bear'against the front surface of the plate at the associated opening 32 to position the free end of the leg at a selected distance beyond the rear surface of the plate 33 to constitute a soldering lug portion, and the other leg of the member 33 is accordingly positioned at a selected distance beyond the forward surface of the plate 30. This position is fixed by a staked fastening as indicated at 35 and more particularly shown in Figs. 11, 12 and 13 and described in detail hereinafter.
A second series of circularly spaced openings 36 punched in the plate 3!} in inward concentric relation to the openings 32 are designed to receive contact members 31. Each of the members 31, as shown in Fig. 3, constitutes a continuous contacting portion 38 coextensive with an arc defined by three or another selected number of) successively arranged contact members 33. Staking of the members 31 as at 33, in the manner of the fastening applied to the members 33 shown in Figs. 11, 12 and 13, serves to rigidly position the contacting portion 38 with its rearward surface in engagement with the front side of the plate 38 and its forward surface in spaced rearward relation to the contact members 33 opposite thereto. This staking also serves to position the free end of the member 3'! projecting rearwardly of the plate 30 at such a distance from the plate 3i as to constitute a soldering lug portion similar and in radially inwardly spaced relation to the corresponding portion of members 33.
A rotor plate 48 of insulating material like that of plate 30, is provided with a non-circular central opening conforming to the cross-sectional contour of the flattened end portion of shaft l0 whereby the rotor may be mounted on shaft l0 inwardly of plate 38 and rotatable with shaft 10 while free to move a limited distance axially of the shaft.
Contact members carried by the rotor 40 for cooperation with selected pairs of axially spaced contact members 33 and 31 of the stationary plate 33, each comprises a U-shaped resilient metal strip or member having a pair of arms 4| and 42 connected as at 43 at one end thereof. The connected end 43 is of such width as to present inwardly offset lateral edges 44 adapted to slidably engage the side or radial edges 45 and d6 of the notch in the rotor near the corners defined by said radial edges 45 and 46 of the notch and a transverse edge 41 at the inner limits of the notch when the connected end 43 is swung or moved in the plane of the rotor to an operative position as shown in Fig. '7 from a position as shown in Fig. 10. An offset portion '58 provided in the edge 4-6 of the notch is accordingly operative to trap the connected end 43 of the arms 4! and 42 against withdrawal from the notch in directions radially of the shaft H on which the rotor 43 is mounted. As shown in Fig. 9 the arms 4! and 42 diverge in a direction away from the connected ends and as shown in Fig. 7 are of such width as to respectively overlie the edges 45 and 46 of the notch and of such length as to extend a distance short of the periphery of the rotor.
An extension or tongue formed at the outer end of the arm 4-2 projects through and slidably engages the edges of the rotor notch when the connecting member 43 is in operative position, as shown in 8, and cars 49 projecting laterally from the free end of the tongue are engageable by the upper surface of the rotor at opposite sides of the notch to limit movement of the tongue away from a position in engagement with the side edges of the notch. The outer end of the arms 4| and 42 are provided with bowl-shaped enlargements 50 and 5| respectively which present surfaces engageable with the inwardly opposed surfaces of corresponding pairs of contacts 33 and 31 on the stationary plate 30. It will be observed in Fig. 10 that the arms 4! and 42 as well as the tongue at the outer end of arm 42 may be flexed apart so as to clear the corner defined by the edge 5 of the notch and the outer edge of the rotor 40 to accommodate lateral swinging movement of the connecting member 33 about one edge 43 thereof positioned between the stop 43 and the side edge 46 between the offset or stop 48 and the inner limits of the notch in the rotor as a pivot, as shown in Fig. 10, toward and away from a position wherein the edges id of the connecting member 43 are in operative position between the edges 45 and 46 of the notch, as shown in Fig. '7.
It will be observed that inasmuch as the opposite edges 5 and 43 of the notch provide a fulcrum with respect to which the arms H and 42 of the contact member may move, the contact members on the rotor plate 43 may rock in a self-aligning manner relative to the contacts carried by the stationary member 35. Positive engagement of the surface portions presented by the bowl shaped enlargements 5:3 and 5! with respect to the contacts on the stationary memher is further assured by the yieldable resistance of the arms ii and G2 to move toward each other under pressure applied by the contacts on the stationary member.
As shown in Figs. l1, l2 and 13, the method of securing the contact members in rigid relation to the stationary member utilizes the added holdin power of a fastener having a cross-sectional contour corresponding to that of a narrow strip of sheet metal, and an opening 32 of such crosssectional form as to initially freely admit entrance of the strip therethrough and thereafter causing the strip to become forcibly jammed therein as the strip is progressively moved into a final seated position therein. The essential features of this type of fastening comprises an opening 32 in the member 33, as shown in Fig. 13, having relative dimensions a and b, and a member corresponding to member 33 shown in Figs. 11 and 12, having a head portion 34, and a neck or shank portion of uniform thickness b, a major dimension a adjoining the head portion 34 and a minor dimension 0 at its leading end. Dimension at being greater than a, and dimension i) being greater than b and dimension c'being less than a, the member 33 when initially inserted in the opening 32 approaches a position of mating engagement with the corners at the entering end of the opening 32 and thereafter operating to distort said corners at the entering end. The staking developed as at 35 in Fig. 11 serves to laterally spread the edges of the member 33 from a position clear of to a position wherein said edges distort the corners at the discharge end of the opening 32. Thus the member is seated solidly against the rear and front sides of the member 35 without the use of rivets or other separate fastening devices. The extreme simplicity with which this method of securing the contact members 33 in the stationary member 30 may be carried out thus greatly reduces the cost of providing a fastening having great holding power.
Figs. 14 and 15 illustrate a switch embodying the features of this invention in conjunction with a front plate 55 of a cup shape cooperating with a rear plate 56, said plates being secured together by means of a series of inwardly bent tongues 57.
The present invention may be embodied in other specific forms without departing from the spirit or essential characteristics thereof. The embodiments contained herein are therefore to be considered in all respects as illustrative and not restrictive, the scope of the invention being indicated by the appended claims rather than by the foregoing description, and all changes which come within the meaning and range of equivalency of the claims are therefore intended to be embraced therein.
What is claimed is:
1. An electric switch comprising a stationary v member, a shaft mounted for rotation about a fixed axis and in central perpendicular relation to the general plane of said stationary member, a rotor mounted for rotation with said shaft, radially extending notches provided in the periphery of the rotor, each notch having a U -shaped resilient contact member trapped therein to secure said contact member against movement relative to said notch in directions radially of the shaft, said U-shaped contact member providing axially aligned contact arms in radial relation to said shaft and diverging in a direction away from said shaft, and axially spaced pairs of rigid contact arms on said stationary member presenting inwardly opposed surfaces with which said rotor contacts are slidably engageable.
2. An electric switch as claimed in claim 1 wherein said U-shaped contact members on the rotor have limited swinging movement relative to the rotor in directions axially of said shaft about edge portions of the notch defining the inner limits of said notch.
3. An electric switch as claimed in claim 1 wherein said U-shaped contact members on the rotor have swinging movement relative to the rotor in directions axially of said shaft about edge portions of the notch defining the inner limits of said notch, and said diverging arms are disposed to respectively overlie opposite edge portions of the notch intermediate the inner and outer limits of said notch.
4 In an electric switch, the combination of a fiat insulated support having a radially extending notch formed in the periphery thereof, a U -shaped resilient member confined in said notch with the arms thereof extending toward but a distance short of the periphery of said support and in divergent relation to opposite faces of the support in a direction away from the inner limits of said notch, and means engageable with the connected ends of said arms to trap the U-shaped resilient member in operative confinement in said notch including an offset portion formed in one of the radially extending edges of said notch.
5. In an electric switch as claimed in claim 4 wherein swinging movement of the arms toward and away from the opposite faces of the support is limited by means including an extension of one of said arms projecting through said notch toward the other of said arms.
6. In an electric switch as claimed in claim 4 wherein swinging movement of the arms toward and away from the opposite faces of the support is limited by means including an extension of one of said arms projecting through said notch toward the other of said arms, said extension being flexible to pass the corner defined by the periphery of the support and the radial edge of the notch about which the U-shaped member is swung in the plane of the support while the connected ends of the arms are engaged by the oifset portion aforesaid as a fulcrum incident to completing assembly of the support and said U -shaped member.
KENNETH C. ALLISON.
REFERENCES CITED The following references are of record in the file of this patent:
UNITED STATES PATENTS Number Name Date 1,704,380 Andres Mar. 5, 1929 1,939,369 Shelley Dec. 12, 1933 2,068,582 Von Hoorn Jan. 19, 1937 2,333,659 Mayer Nov. 9, 1943