US2805297A - Snap switch mechanism - Google Patents

Description

P 1957 G. J. CAMPBELL 2,805,297

SNAP SWITCH MECHANISM Filed April 5, 1954.

2 Sheets-Sheet l i I E MP W l6 24 2,2, /6 n f UM JYWWM GREGG J CAMPBELL Sept. 3, 1957 G. J. CAMPBELL 2,805,297

SNAP SWITCH MECHANISM Filed April 5, .1954 2' Sheets-Sheet 2 m I I Gfif J. CAMPBELL United States Patent SNAP SWITCH MECHANISM Gregg J: Campbell, Freeport, 111., assignor to Guardian Electric Manufacturing Co., Chicago, HL, a corporation of Illinois Application April 5, 1954, Serial No. 420,842

2 Claims. (Cl. 200--67) This invention relates to a snap switch mechanism of comparatively simple construction wherein a leaf spring blade has a longitudinal slot terminating short of one end thereof and extending to the other end thereof, means being provided to draw the two arms of this other end toward each other to stress the blade for snap action.

One object of the invention is to provide a snap acting mechanism of the general character just referred to wherein a novel mounting means is provided therefor in the form of a U-shaped bend and a screw extending through the two arms of the U and into a suitable base or the lfiie, the screw being adjustable to change the character of the snap action of the blade.

Another object is to provide actuating means for a snap acting switch blade or the like comprising means to engage raised side edges of the blade and depress them, the blade having means to limit the throw thereof to less than an over-center position.

Still another object is to provide the two arms of the blade so stressed that the blade has a pair of inner and a pair of outer edges, one pair of which is higher than the other pair, means being provided for supporting the lowerv pair of edges and actuating means engaging the other pair of edges to actuate the blade when the means is moved in a direction toward the blade.

A further object is to provide modified forms of mounting means for the blade which eliminate the U-bend above referred to and provides an anchor that supports the outer edges of the blade so that an actuating element can engage the inner edges thereof, and the actuating element, when depressed, will actuate the blade from one position to the other.

With these and other objects in view, my invention consists in the construction, arrangement and combination of .the various parts of my snap switch mechanism, whereby the objects contemplated are obtained as hereinafter more fully set forth, pointed out in my claims and illustrated in the accompanying drawings wherein:

Fig. 1 is a perspective view of a switch structure incorporating my snap acting mechanism, a portion of the switch housing being broken away to show internal details.

Fig. 2 is an enlarged vertical sectional View on the line 2-2 of Fig. 1.

Figs. Band 4 are vertical sectional views on the lines 33 and 44 respectively of Fig. 2.

Fig. 5 is a plan view of the snap acting blade of my switch structure before assembly.

Fig. 6 is a similar plan view thereof showing a lock applied to the blade for stressing it for snap action.

Fig. 7 is a perspective view of the lock per se.

Fig. 8 is a vertical sectional view through a different type of switch using a modified form of my snap acting mechanism.

Fig. 9 is a vertical sectional view on the line 99 of Fig. 8.

Fig. 10 is a plan view of Fig. 8 with the cover for the switch removed.

Fig. 11 is an enlarged perspective view of an anchor that is used in the type of switch shown in Fig. 8.

Fig. 12 is a plan view similar to Fig. 10 showing another modification of the snap acting blade and an anchor therefor.

Fig. 13 is an enlarged vertical sectional view on the line 1313 of Fig. 12.

Fig. 14 is an enlarged perspective view of the type of anchor used in Figs. 12 and 13.

Fig. 15 is a plan view before assembly of the snap acting blade used in Figs. 10 or 12, and i Fig. 16 is a view thereof with a contact installed and a lock assembled on the blade for stressing it for snap action.

On the accompanying drawings I have used the reference numeral 10 to indicate a base which may be made of sheet metal or the like. The base and the switch mechanism thereon may be covered by a cover such as shown at 12 secured in position by screws 14.

A snap acting blade B is provided. This blade is formed of a leaf spring of suitable resilient material such as spring steel, bronze, or the like, with a slot 22 that extends out to one end but terminates short of the other end at a hole indicated 16 on the drawing. This other end of the blade is curved to U-shape as indicated at 20 and provided with an opening 18 for mounting purposes as will hereinafter appear. Opposite side edges of the blade B are notched as at 24 (see Fig. 5) for a lock 26.

The lock 26 is formed of suitable metal and provided with a contact 28 for circuit controlling purposes. It has a pair of ears 30 that are bent under the blade B as shown in Fig. 3 and the size of the lock is such that when installed as in Fig. 6 it pulls the two arms of the blade B toward each other as illustrated, thus stressing them for snap action.

The blade B is mounted on the base 10 by means of a single screw 32 extending through the openings 16 and 1% and into the base. For convenience, this screw may extend through the base and be provided with lock nuts 34 and 36 as shown in Figs. 2 and 4.

. When the blade B is stressed by means of the lock 26 its two arms in the region just to the left of the screw 32 in Fig. 2 will have their opposite side edges tilted up as in Figs. 3 and 4 or tilted down depending on whether the blade is snapped over center downwardly or upwardly. In order to utilize the inherent snap action in the blade in the switch shown in Fig. l, I limit its throw to less than an over-center position, specificallyin this figure, to a position below the central position between its opposite over-center positions. This may be accomplished by means of the contact bracket 38 carrying a stationary contact 46 for circuit controlling C 0- action with the contact 28 on the lock 26. Insulation is shown at 39 to insulate the contact 41) and the bracket 38 from the base 10.

When the throw of the blade B is thus limited, the opposite side edges of the blade will slant up as shown in Figs. 3 and 4, and when these opposite side edges are depressed to a certain point the blade B will snap from the. closed circuit position to an open circuit position and will return to the closed circuit position with snap action when the pressure on these opposite side edges of the blades is relaxed.

To provide actuating means for this purpose an actuating pin 44 extends from a rectangular head 42 which is prevented from turning by reason of spanning the distance between the sides of the cover 12. The actuating pin extends through an opening 46 in the cover to the exterior thereof where it may be manually or otherwise engaged and pushed inwardly for actuating the switch. The head 42 has a pair of projections 48 for engaging -turn-to the closed-position when the pressure on the'pin is relaxed, the distance of movement being relatively small.

The U-bend 20 and the singlemounting screw 32 provide an inexpensive means for mounting the snap acting switch blade B, and at the same time provides for 'adjustment as the screw 32 can be raised or lowered with respect to the base and will change the snap acting characteristic of the blade.B, causing itto snap with more or.:less force as desired within a certain range of adjustment. This means of mounting is therefore, due to its simplicity, .inexpensive'to manufacture'and at the'same time provides for adjnstingthe snap action'switch'to operate as desired.

In Fig. 8 I show a base 50 in which a snap acting blade B 'is mounted as will "now be described. It is provided with a lock '52 for drawing the sides together and stressing them in 'a manner :similar to the lock.26 of Fig. 7 and the blade 'is provided with a contact 54. Referring-to Fig. 15, the blade B has a slot 58 andnotches 56and 60, the notches 56 beingiprovided for the contact '54 and the notches 60 being provided .for the. lock 52. The lock 52 is merely a strip of metal'with its'ends'bent under the blade the sameas the fingers 30 shown in Fig.7.

The two arms of the blade B have their opposite side edges slanted downwardly as shown in Fig. 9 instead of upwardly as-in the form of the invention shown in Fig. 3. These two edges are supported in Figs. 8, 9 and 10 by the anchor A shown in Fig. 11 and specifically by a.pair of arms 72 and 74 illustrated therein. The anchor A has a blade 76 to overlie the blade B and the anchor and blade are connected to the base 50 by a screw 78 as shown in Fig. 8.

Referring to Fig. 9, the downward slant of the opposite side edges of the arms of the blade B are illustrated and an actuating pin 80 having ahead-82 is shown foractuating this blade by downward depression of the actuating pin. The blade B is limited in its throw by stationary contacts 62 and 64 to co-act with the contact 54 on the blade B, thus providing a double-throw switch. This is merely representative, however, as-the switch can be either normally open or normally closed and, likewise, this is true of the switch shown in Fig. 1 which maybe a double throw switch also if desired. The contact 64 is shown supported by a bracket 65 anchored by a-bo1t 67.

'The limit of throw of the switch blade B' being less than thatrequired to cause it to pass over center, it will spring upwardly when the pin 80 is depressed andwill return to the lower position when the pressure on the pin is relaxed.

'In Figs. 12, 13 and 14 .I show .a modified form of anchor A wherein the anchor is depressed at 84 to provide a pair of raised side edges 86 and 88 to support the lowered side edges of a blade B" .(see' Fig. 13) in place of the arms 72 and 74 for the blade B. in Fig. 9. The action :of the blade B is similar to that described in connection with the blade B as the opposite side edges of the blade slant downwardly as shown in Fig.113 in a manner'similar to those shown in Fig. 9.

I have disclosed snap acting mechanism utilizing 'a slotted and stressed leaf spring confined against movement over center and operated by pressure on certain outer or inner side edges thereof so that a comparatively simple and inexpensive yet practical snap acting mechanism for the operation of switches, valves and the like is provided. The required dimensions of parts are not too critical to permit stamping of the parts from sheet metal and assembly thereof in jigs during the manufacturing process with a minimum of time necessary to be spent in the assembly of each unit. The screwmounting 32 or the anchor mounting A or A readily adapts the 'type of snap acting spring blade shown for snapping upwardly away from the base as a resultfof downward ,pressure on the spring at the proper point or points by an actuating pin that can be'manually or automatically controlled as desired.

Some changes may be made in the construction and arrangement of the ,parts of my snap switch mechanism without departing from the real spirit-and purpose of my invention, and it is my intention to cover by my claims any modified forms of structure or use of mechanical improvements which may be. reasonably included within their scope.

I claim as my invention:

1. A snap acting mechanism' comprising a leaf spring blade having a longitudinal slot terminating .short of one end thereof and extendingto the other endthereof, means to draw the two arms of said other end toward each other to stress said bladefor snap action, means for supporting said blade adjacentsaid other end comprising a U-shaped anchorhaving a portion of one arm bifurcated to form a pair of spaced supports for the side edges of said blade, said one end of said blade being confined between the remaining portion of said'one arm and the other arm of said anchor, an actuating element engageable with said blade at the edgesof, said slot, and means for limiting the throw of said blade to less than an over-center position.

2. In a snap acting mechanism of the character disclosed, a leaf spring 'blade having a longitudinal slot terminating short of one end thereof and extendingto the other end thereof, means to draw the two arms of said other end toward each other'to stress said blade for snap action, a U-shaped'anchor for supporting said blade adjacent said other end, said anchor having a pair of arms to provide spaced apart supports for the side edges of said blade and a portion overlying said blade, a mounting screw for said blade extending through said anchor, said blade and said overlying portion of said anchor, anactuating pin having a head engageable with said blade at -a position centered over said slot and movablein a direction toward the plane in which said arms lie, and meansfor limiting the throw of said blade to less than an over-centerposition.

References Cited in the 'file of this'patent UNITED STATES PATENTS 1,780,758 Leupold Nov. 4, 1930 2,275,642 Nordberg Mar. 10, 1942 2,300,489 Deutschmann Nov; 3, 1942 2,324,798 Nordberg -Iuly20, 1943 2,363,280 Arnold Nov. 21, 1944 2,511,526 Bugge July 13, 1950

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