US3449700A - Magnetically actuated snap-action switch - Google Patents

Description

June 10, 1969 E. GILLILAN I MAGNETICALLY ACTUATED SNAP-ACTION SWITCH Filed :July 31, 1967 INVENTOR.

EDWARD GILL-ALAN HIS AT'FQIQNEY United States Patent 3,449,700 MAGNETICALLY ACTUATED SNAP-ACTION SWITCH Edward Gillilan, Highland Park, 11]., assignor to Cherry Electrical Products Corporation, Highland Park, Ill., a corporation of Illinois Filed July 31, 1967, Ser. No. 657,157 IntfCl. H01h /02, 9/00 US. Cl. 335-188 1 Claim ABSTRACT OF THE DISCLOSURE A magnet-carrying actuator for a snap-action switch which includes a magnet-carrying, flexible switch blade with the magnets presenting like pole faces such that they tend to repulse each other, with the magnet on the actuator restricted to a predescribed path of movement, and with the switch blade being disconnected therefrom and free to move in any direction resulting in a movement of the switch blade into circuit making positions between spaced apart fixed terminals.

The invention is best illustrated by the accompanying drawings in which:

FIG. 1 is a perspective view of the snap-action switch;

FIG. 2 is a side elevational view of the snap-action switch with the side cover removed and showing the parts thereof in their normal unactuated positions;

FIG. 3 is a side elevational view similar to FIG. 2 but showing the parts thereof in their actuated positions;

FIG. 4 is a perspective view of the switch case;

FIG. 5 is a perspective view of the magnet-carrying switch actuator; and

FIG. 6 is a side view of the magnet-carrying flexible switch blade.

Referring to FIG. 1 there is shown a switch 10 which includes a case 11 and removable side cover 12. One end wall 13 of the case 11 is provided with three parallelly extending slots 14, 15 and 16. Positioned in slots 14 and 16 are a pair of elongated contact bearing terminals 17 and 18. Positioned in slot 15 is a blade terminal 19 which as seen in FIG. 6 has a portion of its elongated length reduced as at 20 to provide a flexible blade end 21. The free end of the flexible blade 21 which is positioned within the cavity 22 formed in the case 11 carries a magnet 23.

An actuator 24 is projected through an opening 25 formed in the top wall 26 of the case 11. This actuator 24 .has an enlarged circular head 27 which normally projects externally of the cavity 22 as seen in FIG. 1. Connected to the underside of the circular head 27 of the actuator 24 is a generally T-shaped body portion 28, the free ends of the cross arm of which are adapted to be positioned in and slidably contained in slots 29 formed in the confronting inner wall faces of the case 11 and cover 12. Carried by the bottom portion of the T-shaped body 28 of the actuator 24 is a second magnet 30. Disposed between the magnet 30 and the bottom wall 31 of the casing 11 and contained in a' well 32 is a coil spring33 which normally positions the actuator 24 such that the circular head 27 is exposed through the opening 25 formed in the top wall 26 of the casing 11.

The magnets 23 and 30 are so arranged that like pole faces thereof are positioned in confronting relationship. In the present illustration the north pole faces of each of the magnets are positioned in confronting relationship.

When the actuator 24 is moved within the switch 10, the magnet 30 carried thereby will pass in close proximity to the magnet 23 of the flexible blade 21. As like magnetic pole faces repel each other, this downward movement of magnet 30 will cause magnet 23 to move in a likewise downward direction so as to increase the contact pressure between the contact 34 carried by the blade 21 and the contact 35 carried by the inner end of the terminal 18. After the actuator 24 has been moved in its guided path formed by the slots 29 to a point where the magnet 30 carried thereby passes below the center line of the forces of magnet23, the repulsion between the like pole faces of these magnets will cause the switch blade 21 to move upwardly until the contact 34 carried thereby engages contact 36 carried at the inner end of the terminal 17. The downward distance of travel of the actuator 24 is limited by the size of its head 27, which when it is depressed into the opening 25 its full depth, as seen in FIG. 3, it can no longer be moved. Thus the magnet 30 is in a position where its repulsion force maintains contact pressure between contact 34 and terminal contact 36.

I have provided a switch Where the switch blade is movable Without physical attachment or engagement by any moving member. The arrangement of the repulsing magnets in close proximity to each other with one movable through a controlled path results in a switch where the first contact between the switch blade and a terminal is increased before breaking by the resulting movement of the switch blade. An added and extremely desirable feature is obtained through the use of the magnetic force fields in that the switch is teaseproof; that is, the movement of the blade 21 is a positive reaction to the magnetic fields around it and cannot be suspended between the fixed terminals. Without physical contact or deformation by a movable member the life span and electrical capacity of the blade is increased.

While I have illustrated and described the preferred form of construction for carrying my invention into effect, this is capable of variation and modification without departing from the spirit of the invention. I, therefore, do not wish to be limited to the precise details of construction set forth, but desire to avail myself of such variations and modifications as come within the scope of the appended claim.

Having thus described my invention, what I claim as new and desire to protect by Letters Patent is:

1. A magnetically-actuated switch, including a housing providing spaced-apart parallelly extending fixed terminals and an elongated switch blade having a free end extending therebetween and carrying a contact movable into and out of contact with either of the terminals wherein the improvement comprises:

(a) an actuator movable through the housing perpendicular to the terminals and in spaced close proximity to the free end of the switch blade,

(b) guide means provided by said actuator within said housing and cooperating therewith to guide said actuator in a fixed perpendicular path to close proximity to the free end of the switch blade,

(0) guide slots of a predetermined length formed in confronting walls of the housing for receiving said guide means provided by said actuator for guiding and limiting the movement of said actuator through its path relative to the free end of the switch blade,

(d) a magnet carried by the actuator within the housing and movable with said actuator through its guided and limited path in close proximity to the free end of the switch blade,

(e) said switch blade having a portion of its length reduced in thickness to provide a flexible free end which carries a second magnet beyond the ends of said spaced terminals and in close proximity to the 4 tween said magnets for returning said actuator and its magnet to their original position, and effecting the return movement of the switch blade and its magnet to their original position.

path of travel of said actuator and the magnet carried thereby,

(f) each of said magnets being magnetized parallel to the long axis of said switch blade and in an 0pposite direction of polarization so that said magnets act to repulse one another such that when said actuator and its magnet is moved in one direction through its guided and limited path the actuators magnet will FOREIGN PATENTS repulse said second magnet so that said free end of 1,432,447 2/1966 Fran said switch blade is caused to'move in an opposite direction to the direction of movement of said actu- 15 BERNARD GILHEANY, Prlmary Examine"- ator lts m g a H. BROOME, Assistant Examiner.

(g) a coil spnng 1n axial alignment with said actuator for yieldably resisting movement thereof through the U CL X,R housing in one direction, and having an expansion 335.. 2()6 force greater than the magnetic repulsing force beo 5 References Cited UNITED STATES PATENTS 2,624,809 1/1953 Sinclaire.

3,273,091 9/1966 Wales. 10

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