US2994750A - Snap acting switch - Google Patents

Description

Aug'. 1, 1961 A. F. RAAB 2,994,750

SNAP ACTING SWITCH Filed Hay 2, 1958 United States Patent C 2,994,750 SNAP ACTING SWITCH Andrew F. Raab, Morton Grove, Ill., assignor to Littelfuse, Inc., Des Plaines, Iii., a corporation of Illinois Filed May 2, 1953, Ser. No. 732,571 2 Claims. (Cl. 20G- 67) The principal object of this invention is to provide irnprovements in a snap acting switch having a pivotally mounted carrier which is snapped in opposite directions about its pivot axes, the improvements being directed to the manner of stopping the carrier in its snapping movement and to the manner of supporting the contact member on the carrier for movement thereby.

Such a snap acting switch may be of the type including a pivotally mounted carrier having a pair of angularly spaced seats and a guide element therebetween and a double faced lock cam. A trip lever is adapted alternately to engage the spaced seats of the carrier for pivotally moving the carrier in opposite directions. A lock bar is slidably mounted adjacent the carrier and has a lock lug thereon normally alternately engaging the faces of the lock cam to prevent pivotal movement of the carrier in said opposite directions. Means are provided for resiliently pressing the trip lever against the seats of the carrier and for slidably moving the lock bar to disengage the lock lug thereof from the lock cam of the carrier to snap the carrier in opposite directions about its pivot axis.

In the past, the snapping of the carrier in its opposite directions has been stopped at its alternate positions by the lock lug on the lock bar and, as a result, the lock lug has often broken away because of fatigue thereof because of the incessant pounding thereof by the snapping carrier. To eliminate this difiiculty, Ellithorpe Patent No. 2,604,- 793, dated July 29, 1952, proposed the use of fixed stops on the housing to stop the snapping movement of the carrier but this introduced certain other objectionable factors. In accordance with one aspect of the present invention, the pivotally mounted carrier is provided with a pair of angularly spaced stop shoulders which engage the sturdy slidably mounted lock bar when the carrier is snapped to one position or the other for stopping the carrier at said positions. `Fatiguing and breakage of the stop lug and the objectionable factors of the said Ellithorpe patent structure are thus eliminated.

In regard to the other aspect of the present invention, the contact member, which selectively engages the spaced stationary contacts, is carried by a bowed leaf spring which affords contact pressure between the contact member and the contacts. The bowed leaf spring is provided with a pair of holes which receive a pair of spaced projections on the carrier for readily and resiliently mounting the contact member on the carrier to move the contact member into selective engagement with the contacts as the carrier is snapped in opposite directions about its pivot axis.

Further objects of this invention reside in the details of construction of the snap action switch and in the cooperative relationships between the component parts thereof.

Other objects and advantages of this invention will become apparent to those skilled in the art upon reference to the accompanying specification, claims and drawing in which:

FIG. 1 is a perspective view of the snap action switch of this invention.

FIG. 2 is a vertical sectional view taken substantially along the line 2-2 of FIG. l and illustrating the snap acting switch in released position.

FIG. 3 is a vertical sectional view taken substantially along the line 3-3 of FIG. 2.

FIG. 4 is a vertical sectional View similar to FIG. 2

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but illustrating the snap acting switch as it is being operated.

FIG. 5 is a partial vertical sectional view similar to FIGS. 2. and 4 but illustrating complete operation of the snap acting switch.

FIG. 6 is a horizontal sectional view taken substantially along the line 6-6 o-f FIG. 2.

FIG. 7 is a perspective view of the lock bar.

FIG. 8 is a perspective view of the tripping lever.

FIG. 9 is an elevational view of the pivotally mounted carrier but showing the side thereof opposite to the side illustrated in FIGS. 2, 4 and 5.

FIG. 10 is an exploded perspective view illustrating the manner of securing the contact member to the carrier.

The snap action switch of this invention is generally designated at 10 and it may be utilized as a Vfoot operated switch for dimming the headlights of an automotive vehicle. It includes a housing 11 which is preferably diecast from suitable metal. The housing 11 has an upper portion 12 having a cylindrical cavity which opens upwardly and a lower portion 13 having a cavity which opens laterally as indicated at 15. The housing has a transverse partition 14 between the upper and lower cavities. The lower portion of the housing is provided with suitable apertured mounting ears 16 for mounting the snap action switch.

The lower portion 13 of the housing has a bearing member 18 projecting into the cavity and this bearing member 18 is provided with a hole 19 -for receiving a pin projection 20 on a carrier 21. The carrier 21 is preferably made from an electrical insulating material such as nylon or the like. The pin projection 21 pivotally mounts the carrier in the bearing member 1S of the housing. The top edge of the carrier 21 is provided with a pair of angularly spaced seats 22 and 23 and with a pointed guide element 24 therebetween. The rear `face of the carrier 21 adjacent the bottom thereof, as shown in FIG. 9, is provided with a double faced lock cam 25 which is formed by recessing the rear face of the carrier as indicated at 26 and 27.

A lock bar 30 formed of stamped steel or the like is slidably mounted in an opening 31 in the transverse partition 14 of the housing and it is also provided with an elongated slot 32 which encompasses the pin projection 20 of the carrier 21. The lock bar 30 is thus guided for upward and downward longitudinal movement. The lock bar 30 extends adjacent the rear face of the carrier 21 and is provided with a lock lug 33 which extends into the recess 26 and 27 of the carrier and engages the opposite sides of the lock cam 25 depending upon the position of the carrier. The upper end of the lock bar 30 is provided with an extension 34 for securing a button or cap 35 to the lock bar, this being done by peening the extension 34. A coil spring 36 is arranged between the cap 35 and the transverse partition 14 for resiliently maintaining the cap and the lock bar 30 in an elevated position with the lock lug 33 at the upper ends of the grooves 26 or 27.

The lock bar 30 is provided with an elongated slot 38 which receives the transverse arm 39 of a trip lever 49, the arm 39 having a notch 41 for maintaining the trip lever in place in the slot 38 in the lock bar 30. The trip lever 40 extends downwardly -adjacent the lock bar 36 and through the opening 31 in the transverse partition 14 to a point adjacent the spaced seats 22 and 23 and guide element 24 on the carrier 21. Here, also the lock bar 40 may be formed from stamped metal. A cupped spring seat 43 is slidably mounted on the lock bar 30 above the arm 39 of the tripping lever 40. A spring 44 is interposed between the spring seat 43 and the cap 35 for resiliently pressing the spring seat 43 against the arm 39 of the tripping -lever 40. This operates normally to maintain the tripping lever at the lower end of the slot 38 and in a position substantially radial to the pivot axis on the carrier 21 as illustrated in FIG. 2.

FIG. 2 illustrates the parts in their normal released positions with the carrier maintained in one position by reason of the lock lug 33 engaging one side of the lock cam 25. When the cap 35 is depressed, as illustrated in FIG. 4, the lower end *42 of the tripping lever 40 is guided by the guide element 24 into the seat 22, the tilting of the trip lever 40 being permitted by reason of its association with the slot 38 and the spring seat 43. As depression of the cap 35 continues, the lock bar 30 is moved downwardly while downward movement of the trip lever 40 is prevented by the locked carrier 21. As a result, the yforce of the spring 44 increases. When the lock bar 30 is depressed suiiiciently to release the lock lug 33 from the lock cam 25, the spring 44 operates through the trip lever 40 to snap the carrier 21 to the opposite position as shown in FIG. 5. When the cap 35 is released, the lock bar 30 and the trip lever 40 are raised by the spring 36 to the position illustrated in FIG. 2 and at this time the carrier 21 is locked in the opposite position, as -illustrated in FIG. 5, by the lock lug 33 engaging the other side of the Alock cam 25. The carrier 21 may then be snapped from the position shown in FIG. to the position shown in FIG. 2. by the same operation as described above and, accordingly, a further description is not considered necessary. In this way, the pivotally mounted carrier is selectively snapped in opposite directions about its pivot axis.

The rear face ofthe carrier 21 is provided with a pair of angularly spaced stop shoulders 46 and 47 which are adapted automatically to engage opposite sides of the lock bar 30 when the carrier is snapped from one position to the other. This is illustrated in FIG. 5 where the carrier has snapped 4from the position shown in FIG. 2 to the position shown in FIG. 5. Thus, stopping o-f the carrier in its snapping movement from one position to the other is accomplished by the stop shoulders 46 and 47 engaging the rugged and strong lock bar 30. This prevents fatiguing of the relatively weak stop lug 33 and accurate positioning of the carrier 21 with respect to the lock bar 30 is assured.

The front face of the carrier 21, as illustrated more clearly in FIG. l0, lis provided witha pairof spaced projections 50 having shoulders 51. A contact member 52 is suitably secured, as by spot welding 53, to a bowed leaf spring 5'4. The bowed leaf spring 54 has a pair of holes 55 therein which receive the spaced projections 50 on the carrier, the bowed leaf spring seating against the shoulders 51. The initial bowing of the leaf spring 54 is such that'the holes 55 engage the sides of the projections 50 so as to secure the leat spring and hence, the contact member to the carrier.

A terminal member 57, yformed of suitable insulating material such as Bakelite or the like, is secured in the opening in the lower portion 13 of the housing 11 as by means of offsetting the housing thereat as indicated at 58 in FIG. 1. Secured within holes in the terminal member 57 are contacts 59, V 60 and 61, the inner ends of these contacts being turned over, as illustrated in FIG. 3 so as to be engaged by the contact member 52. The outer ends of the contacts 59, `60 and 61 are provided with suitable holes for facilitating electrical connection thereto. The contact 59 is in substantial alignment with the pivot axis of the carrier 21 while the terminals 60 and 61 are spaced apart and spaced ya considerable distance from the pivot axis. The contact member 52 continually engages the contact 59 and alternately engages the contacts 60 and 61 as the carrier 21 is snapped from one position to the other. rIlhe bowed leaf spring 54, in addition to securing the contact member 52 to the carrier 21 also affords desired contact pressure between the contact member 52 and the contacts 59, 6 0 and 61. Accordingly, extremely satisfactory switching operations are obtained and, in addition to providing a wiping action at contacts 60 and `61, a wiping action is also provided at contact 59.

While yfor purposes of illustration, one form of this invention has been disclosed, other forms thereof may become apparent to those skilled in the art upon reference to this disclosure and, therefore, this invention is to be limited only by the scope of the appended claims.

I claim as my invention:

l. In a snap acting switch including a pivotally mounted carrier having a pair of angularly spaced seats and a guide element therebetween and a double faced lock cam, a trip lever adapted alternately to engage the spaced seats of the carrier yfor pivotally moving the carrier in opposite directions, a lock bar slidably mounted adjacent the carrier and having a lock lug thereon normally alternately `engaging the faces of the `lock cam to prevent pivotal movement of the carrier in said opposite directions, and means for resiliently pressing the trip lever against the seats of the carrier and for slidably moving the lock bar to disengage the lock lug thereof from the lock cam of the carrier to snap the carrier in opposite directions -about its pivot axis, a pair of angularly spaced stop shoulders on the carrier engaging the lock bar when the carrier is snapped to one position or the other for stopping the carrier at said positions, a pair of spaced projections on the carrier, a bowed leaf spring having its concave side facing the carrier and having holes therein receiving and resiliently engaging the spaced projections by which t'he bowed -leaf spring is removably mounted on the carrier, a contact member secured centrally to the bowed leaf spring, and spaced contacts facing the convex side of the bowed leaf spring and selectively engaged by the contact member as the carrier is snapped in opposite directions -about its pivot laxis, said bowed leaf spring affording contact pressure between the contact member and the contacts.

2. In a snap acting switch including a pivotally mounted carrier having a pair of angularly spaced seats and a guide element therebetween and a double faced lock cam, a trip lever adapted alternately to engage the spaced seats of the carrier for pivotally moving the carrier in opposite directions, a lock bar slidably mounted adjacent the carrier and having a lock lug thereon normally alternately engaging the faces of the lock cam to prevent pivotal movement of the carrier in said opposite directions, and means for resiliently pressing the trip lever against the seats of the carrier and vfor slidably moving the lock bar to disengage the lock lug thereof from the lock cam of the carrier to snap the carrier in opposite directions about its pivot axis, a pair of angularly spaced stop shoulders on the carrier engaging the lock bar when the carrier is snapped to one position or the other for stopping the carrier at said positions, spaced contacts, a contact member adapted to selectively engage the spaced contacts, a bowed leaf spring carrying the contact member at the center of the convex side thereof and `affording contact pressure between the contact member and contacts and having a pair of spaced holes therein, and a pair of spaced projections on the carrier received in and engaging the edges of the holes in the bowed leaf spring for resiliently removably supporting the latter and for moving the contact member to selectively engage the contacts as the carrier is snapped in opposite directions about its pivot axis.

References Cited in the le of this patent UNITED STATES PATENTS 2,085,539 Morris June 29, 1937 2,647,180 Tregoning July 28, 1953 FOREIGN PATENTS 1,111,214 'France oct. 2.6, 1955

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