US2318768A - Electric switch - Google Patents

Description

May 1l 1943- w. M. FOSTER Erm. 2,318,763

ELECTRIC SWITCH Filed Oct. 26, 1940 35 Eq' a M'liam Masder c .Mamas Ifrafy zNvEzvToRs Patented May l1, 1943 ELECTRIC SWITCH William M. Foster and Thomas W. Drury, Bronson, Mich., assignors to H. A.

Douglas Mfg. Co., l

Bronson, Mich., a corporation of Michigan Application October 26, 1940, Serial No. 362,954

(c1. aol- 56) 1 Claim.

This invention relates generally to electrical switches and primarily to the rotary type having a resistance associated therewith.

' One object of the invention is to provide an electric switch which consists of very few parts which may be easily and quickly assembled on a production basis, and one which is very efcient in action electrically and mechanically.

Another object .is to provide a switch with a plurality of attaching means whereby the switch may be secured to a support through the agency of either means. y

A further object is to provide an improved assembly whereby the bridge means of the switch is adapted to cooperate with the resistance and contact means mounted on the carrier.

Other objects and advantages of the invention will be apparent after reading the description hereinafter set forth in conjunction with the drawing annexed hereto.

Referring to the drawing:

Figurel is a top view of the electric switch, a portion of which is shown in section to illustrate certain details of construction;

Figure 2 is a vertical section taken substantially on line 2 2 of Figure 1, and clearly shows the construction and arrangement of the majority of the switch parts;

Figure 3 is a section taken substantially on line 3-3 of Figure 2, and shows the switch in an oli position;

Figure 4 is a section taken substantially on line 4-4 of Figure 2 showing the bridge in engagement with the resistance to place the switch in an on position; and

Figure 5 is a bottom view of the contact carrier showing the contact means carried thereby.

The switch illustrated .in the drawing may be used wherever found applicable, but is preferably adapted to be mounted on the instrument panel of an automotive vehicle for the purpose of controlling the volume of illumination of a certain lamp or lamps associated with various instruments carried by the panel.

y The switch, among other things, preferably includes a casing generally designated I, a carrier 2 secured to the casing, a resistance elementv 3 carried by the carrier, a bridge means 4, and operating means 5 which when rotated in the proper direction will cause the bridge means 4 tov slidably engage the resistance element 3.

The switch casing will first be described, and as clearly shown, preferably includes a circular top end wall portion 6 having continuations I exthe contact tending outwardly therefrom in the same plane. The continuations 'I may be provided with apertures 8 through which means may be extended for'securing the switch relative to a suitable support such as the instrument panel of an automotive vehicle. These continuations are preferably arranged diametrically opposite to each other and are formed by striking out portions from the cylindrical wall portion of the casing, and consequently the length of the continuations are substantially equal to the distance between the portion 6 and the carrier 2. As the result of striking out the continuations 1, the casing also includes two oppositely disposed substantially semi-cylindrical or arcuate portions 9 and I0, within the confines of which is disposed certain parts of the switch mechanism such as the bridge 4. The casing and carrier 2 may be secured together in any suitable manner, but as herein shown the arcuate portion 9 of the casing is provided with a pair of spaced apart axially extending ngers I I, and the arcuate portion I0 with an axially extending nger I2. The pair of ngers I I and the finger I2 are adapted to cooperate with the pair of notches I3 and a notch I4, respectively, provided in the periphery of the carrier 2. The ngers and notches are so constructed and arranged that the carrier may be assembled with the switch casing in only one relation, and the extremities of the ngers are bent over against the outer surface of the carrier 2 as indicated at I5 in Figures l and 2 to firmly anchor the carrier to the casing. The carrier is of such a i size that it provides a back and closes off one end of the casing. e

Referring to the construction of the carrier 2, same is preferably made of moulded porcelain or some other desirable insulating material, and as most clearly shown ,in Figures 2 through 4, its upper part is provided with a circumferentially disposed recess I 6. This recess is substantially semi-circular in cross-section and receives the round convolutions of the resistance element 3, the depth of the recess being such that the upper extremity of the element is disposed slightly above the upper surface of the carrier for engagement by the bridge 4. One end of the element 3 is secured within the arcuate recess I6 by means of a contact Il, and its other end engages an abutment I8 formed by an upstanding rest I9. This rest separates the extremities of the resistance element 3, and its upper surface is arranged in the same plane as the upper surface of Il, and the coil 3. The contact is preferably inset with respect to the upper surface of the carrier. Small quantities of cement as indicated at |99 are preferably used to firmly secure the resistance element 3 within the recess I6.

A pair of terminal posts generally designated 26 and 36, adapted to receive plug conductor terminals, are secured to the outer surface of the carrier. Both posts are substantially identical, and therefore a description of one is believed to be sufficient. As most clearly shown in Figures 2 and 5, the post 26 is preferably comprised of a member 2| and a guard 22. The member 2| includes a flat base portion 23 which engages the outer Surface of the carrier 2, and a split cylindrical tubular resilient terminal receptacle 24 which projects substantially outwardly at right angles with respect to the base 23. The guard 22 is preferably made of relatively heavy stock, and includes a base portion 25 which is superimposed on the base portion 23, and a cylindrical tubular portion 26 which substantially surrounds the receptacle 24. The portion 26 is concentrically arranged with respect to the receptacle 24, and is of a size suicient to permit the receptacle 24 to expand when a plug conductor terminal is connected thereto, and at the same time, limits the expansion of the receptacle 24 beyond reasonable limits, and protects same from injury.

The contact |1, above referred to, is provided with a shank 21 which extends through an aperture 23 provided therefor in the carrier, through apertures provided in the base portions 23 and 25 of the post, and is headed over as indicated at 29 to secure the post 26 in place. To prevent rotation of the post with respect to the carrier, the carrier is preferably provided with a small recess 36, and the end of the base 25 of the guard is provided with a lug 3| which seats in the recess, as clearly shown in Figure 5.

The upper surface of the carrier 2 in addition to the provision of the recess I6, is preferably provided with a centrally disposed circular depression 3|. A contact member 32 in the form of an annular disc is seated within this depression. The contact 32 includes a base portion 33 which engages the bottom of the depression 3| and an outer annular ring portion 34, which is offset with respect to the portion 33, engages the upper surface of the carrier 2, as clearly shown in Figure 2. A headed elongated rivet 35 projects through a hole provided in the contact 32 and through a center hole provided therefor in the carrier 2, and likewise through apertures in the base portions of the terminal post 36, and is headed over to secure the post 36 in place. Although it is not essential, it is to be noted that the head of the rivet 35ris arranged within the confines of the contact 32 with its top surface iiush with the top surface of the annular portion 34 of the contact. In any event, the contact 32 and rivet 35 are so arranged that the inner end of the shaft 5 cannot engage same. It is thus apparent that the carrier and parts directly associated therewith are firmly secured in their respective positions.

As mentioned above, one object of the invention is to provide at least two different forms of attaching means, either of which may be employed for securing the switch relative to a suitable support. The radially extending continuations 1 constitute one of these means.

The other means employed for securing the switch'v to a support will now be described. A tubular bearing member 31 is secured to the switch casing, and, among other things, includes a tubular extremity 38, and an extremity 39, the latter of which is of a diameter somewhat less than the outer diameter of the extremity 38. The inner end of bearing 31 is provided with a reduced part which fits within a circular hole in the end wall 6 of the casing, and is flanged over against the end wall 6 as clearly indicated at 46. The extremity 38 is preferably provided with a well or chamber 4|, and the extension 39 with exterior threads 42 and a hole 43. The operating means or shaft 5 is mounted in this hole 43, and as clearly shown, the outer extremity of the shaft projects 'beyond the extension 39 so that a handle may be secured thereto, and the inner extremity of the shaft projects into the casing and is provided with a tongue 44. In order to maintain the shaft in the position shown, the shaft is provided with a reduced portion or neck 45 within which is secured a U-shaped collar 46. The use of this collar is economical as compared to the cost of machining a shaft to provide an abutment correspending to the collar. The extension 39 is adapt?,

ed to be fitted through a suitable opening in a support, and a clamping member such as a nut is adapted to cooperate with the threads 42 to clamp the switch in place. Accordingly, it is apparent that the continuations 1 provided on the switch casing may be utilized for securing the switch to a support incertain instances, and in other instances the extension 39 in conjunction with a nut may be employed.

A carrier 41 to which is secured the bridge 4 is Secured to and carried by the tongue 44 provided adjacent the inner extremity of the rotatable shaft 5. A helical spring 48 is arranged within the well 4| of the bearing with one end engaging the collar 46, and its other end the upper surface of the carrier 41, and functions to urge the collar 46 outwardly against the bottom of the well 4| and the bridge carrier and bridge 4 inwardly so as to present the bridge with respect to the contacts |1 and 32 and resistance element 3. The

carrier 41 is preferably provided with a substantially rectangular aperture 49 which receives the tongue 44 above referred to so as to prevent rotation of the carrier relative to the shaft. The carrier 41 is also provided with a pair of peripherial notches 56 and 5| and an outwardly extending projection 52 near the notch 5|. 'Ihe notches 59 and 5| are preferably diametrically disposed.

Considering now, the construction of the bridge member 4, same, among other things, includes a substantially flat rectangular portion 53. The ends of this portion are provided with upturned lugs 54 and 55 which t into the notches 50 and 5|, respectively, to secure the bridge to the carrier. Projecting angularly outwardly from one side of this portion is an extension 56, the extremity of which is provided with a curved contact 51 which is adapted to cooperate with the resistance element 3 including the contact |1 and rest I9. The opposite longitudinal side of the portion 53 is preferably provided with a contact 58 which projects outwardly substantially` at right angles to the portion 53, and its free extremity is preferably rounded to some extent to provide a contact adapted to cooperate with the annular portion 34 of the center contact 32,

as clearly shown in Figures 2 and 4. The central portion of portion 53 is preferably provided with a rectangular aperture 59 so as to provide clear-A ance for the tongue 44 and prevent same from coming into electrical contact with the bridge member.

As mentioned above, the carrier 41V is provided with a projection 52. This projection is adapted to engage a stop 60 formed by striking in a portion of the arcuate section I of the switch casing, as clearly shown in Figures 1 and 3, to predetermine the complete on and ofi positions of the switch.

To operate the switch, to place the resistance element 3 in the electric circuit it is only necessary to rotate the operating means or shaft 5 so as to move the contact 51 of the bridge member I oil the rest I9 of insulating material onto the resistance element. As clearly shown in Figure 3 the switch is in an 01T position with the contact 51 engaging the rest I9, whereas, in Figure 4 the contact 51 is shown engaging the resistance element near its mid point to include slightly less than one half of the resistance in the circuit, and in Figures 1 and 2 the contact 51 is in engagement with the contact I1 to exclude the resistance and make a direct circuit between the contacts I1 and 32. Thus, it is apparent that when the bridge member 4 is rotated to disengage the contact 51 from the rest I9 to a point where the projection 52 engages the stop 60 the resistance element is excluded from the electric circuit. Obviously, when the contact 51 first engages the element the entire resistance is included in the electrical circuit. It will also be noted that in all of the positions of the bridge member just referred to or in any other position that the contact 58 of the bridge 4 is adapted to continuously engage the annular contacting portion 34 of the contact 32.

Having thus described our invention, it is obvious that various immaterial modications may be made in the same without departing trom the spirit of the invention; and, therefore, we do not wish to be understood as limiting ourselves to the exact form, construction, arrangeof said casing, said carrier said bridge carrier and a ment, and combination of parts herein shown and described.

We claim:

An electric switch including, a cupped shaped casing, a relatively thick carrier of insulating materia] secured to and closing off the open end having a at side, a pocket provided in the center of said carrier, a ring contact member having a round dished portion tting within said v.pocket and an annular portion engaging the iiat surface of said carrier, a recess in said carrier concentrically arranged with respect to said ring contact, a resistance element substantially surrounding said ring contact disposed in said recess, the surface of said element adapted to be engaged being arranged in substantially the same plane as the contact surface of said ring contact, a tubular bearing member having a well secured to the opposite end of said casing, operating means rotatably mounted in said bearing, a bridge carrier attached to the inner extremity of said operating means, a bridge member having lugs extending in one direction therefrom interengageable with pair of contact arms extending therefrom in an opposite direction, one of said contact arms being adapted to continuously engage said ring contact and the other contact arm said resistance element, a spring seated in the well of said bearing member and engaging said bridge' carrier for urging said bridge member in a direction to engage said ring contact and said element, a stop provided on said casing and a projection on said bridge carrier engageable with said stop for limiting the rotary movement of said bridge member.

WILLIAM M. FOSTER. THOMAS W. DRURY.

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