US1924777A - Limit switch - Google Patents

Description

g 1933. A. M. FLANDERS El AL- LIMIT SWITCH Original Filed May 19. 1932 gwuamtozd a. 772.7Zanders J 7. Jessureau wiwwo WWW aw Patented Aug. 29, 1933 UNiTED STATES PATENT orrics LIMIT SWITCH Allen M. Flanders and Joseph T. Dessureau, Barre, Vt.

4 Claims.

This application is a division of our parent application, Serial No. 612,318, filed May 19, 1932, on a Motor controlling means including a novel limit switch, and this case is directed to said 5 switch.

The principal object of the invention is to provide an exceptionally simple and inexpensive limit switch, yet one which will be efficient and dependable, and with this and minor objects in 10 view, the invention resides in the novel subject matter hereinafter described and claimed.

Fig. 1 is a side elevation. Fig. 2 is a top plan view. A preferred construction has been shown and will be specifically described, with the understanding however, that variations may be made within the scope of the invention as claimed.

The numeral 5 on the drawing denotes a panel or base. Upon this panel or base, two swingable arms 6 are mounted, said arms diverging toward their free ends. Preferably, these arms are formed from a single strip of spring metal, and the connecting portion '7 between said arms is secured upon an angle metal bracket 8 in turn mounted upon the base or panel 5. The free ends of the arms 6 are bent into arched form as denoted at 9, to provide cams 10 at the inner sides of said arms, and spring contacts 11 at the outer sides thereof. The arms 6 are normally held by their own resiliency, against two stop pins 12 carried by the base or panel 5, and when said arms are in engagement with said stop pins, the spring contacts 11 are spaced from stationary contacts 13 carried by the base or panel 15. The fixed contacts 13 are preferably formed by laterally bending the opposite ends of a metal strip 14 which is secured at 15 to the panel 5, in a plane parallel with the plane in which the arms 6 are movable, the strip being transverse to the arms, as shown.

Two shoes 16 are provided for engagement with the cams 10 to alternately move the arms 6 to bring their contacts 11 into engagement with 5 their respective contacts 13. In the present showing, the shoes 16 are carried by stems 17 which are adjustably held by set screws 18 in a clamp 19 on the end of a traveling member 20. A suitable guide 21 is provided for this traveling memher, and any desired means may be employed for actuating said member. In the present disclosure, this member is provided with a nut 22 through which a screw 23 is threaded, and when the switch is used for limiting the rotation of an electric motor such as that shown at 24, said motor may drive said screw through the instrumentality of reduction gearing 25.

The invention is used primarily in connection with motor-controlling means which effects driving of the motor in one direction and later effects driving of said motor in the other direction. When the motor has about completed its rotation in one direction, one of the shoes 16 strikes one of the cams 10, thereby swinging one of the arms 6 to bring its contact 11 into engagement with the adjacent fixed contact 13, so that a motorstopping circuit may be completed. Later when the motor is driven in the other direction, and has about completed its rotation in said direction, the other shoe 16 strikes the other cam 10, thereby 7O swinging the other arm 6 to such position that its contact 11 will strike the adjacent fixed contact 13, again establishing a motor-stopping circuit.

It will be seen from the foregoing that the switch is of exceptionally simple and inexpensive construction, yet that it will be efiicient and reliable and possesses so few parts that there is no liability of any of them becoming disarranged and inoperative. I

While the details disclosed are preferable, attention is again invited to the fact that variations may be made within the scope of the invention as claimed.

We claim: 7

1. A switch comprising a base, two swingable arms mounted on said base, said arms being normally spring-held in one position, a fixed metal strip secured to said base in a plane parallel with the plane of movement of said arms, said strip having free laterally bent ends disposed in the paths of said arms and alone constituting fixed contacts for co-action with said arms.

2. A switch comprising a base, a spring attached fixedly to said base and having an arm projecting from its point of attachment, the free end of said arm being bent obliquely at an obtuse angle to the length of said arm to provide a cam, being then bent outwardly in a direction away from the aforesaid point of attachment, and being finally bent into opposed substantially parallel relation with said cam to provide an elongated resilient contact finger, a fixed contact secured to said base in co-operative relation with said resilient contact finger, and means co-operable with said cam for springing said arm to engage said resilient contact finger with said fixed contact.

3. A switch comprising a base having a lateral bracket, an elongated spring secured centrally between its ends to said bracket and widely diverging from said bracket to provide spring arms, the free ends of said arms being bent obliquely at obtuse angles to the inner sides of said arms to provide two cams being then bent outwardly in directions away from said bracket, and being finally bent into opposed substantially parallel relation with said cams to provide elongated resilient contact fingers, fixed contacts secured to said base in co-operative relation with said resilient contact fingers and means co-operable with said cams for springing said arms to engage said resilient contact fingers with said fixed contacts.

4. A switch comprising a base having a lateral bracket, an elongated spring secured centrally between its ends to said bracket and widely diverging from said bracket to provide spring arms, the

free ends of said arms being bent obliquely at obtuse angles to the inner sides of said arms to provide two cams, being then bent outwardly in directions away from said bracket, and being finally bent into opposed substantially parallel relation with said cams to provide elongated resilient contact fingers, a metal strip secured between i'ts ends to said base and extending transversely of both of said arms between the ends of the latter, said metal strip having free laterally bent ends alone constituting fixed contacts disposed at the outer sides of said resilient contact fingers, and means co-operab1e with said cams for springing said arms to engage said resilient contact fingers with said fixed contacts.

ALLEN M. FLANDERS.

JOSEPH T. DESSUREAU.

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