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Publication numberUS2782278 A
Publication typeGrant
Publication dateFeb 19, 1957
Filing dateApr 27, 1954
Priority dateApr 27, 1954
Publication numberUS 2782278 A, US 2782278A, US-A-2782278, US2782278 A, US2782278A
InventorsPeters Max D
Original AssigneeMinjeapolis Honeywell Regulato
Export CitationBiBTeX, EndNote, RefMan
External Links: USPTO, USPTO Assignment, Espacenet
Magnetic snap switch
US 2782278 A
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Description  (OCR text may contain errors)

Feb. 19, 1957 D. PETERS 2,782,278

MAGNETIC SNAP SWITCH Filed April 2'7, 1954 I 26 l8 I 24 I i9 0 A L 32;-

23 J 6J8 as INVENTOR MAX 0. PETERS BY j ATTORNEY United States Patent MAGNETIC SNAP SWITCH Max D. Peters, Minneapolis, Minn., assignor to Minneapolis-Houeywell Regulator Company, Minneapolis, Minn., a corporation of Delaware Application April 27, 1954, Serial No. 425,871 13 Claims. (31. 200-67) This invention relates to switches and more particularly to magnetic snap switches.

One embodiment of my invention has as the basic elements of the switch, three contacts, opposed magnets, and a moving element. supported at its center of gravity by a thin stainless steel wire. I depend on the torsion of the wire to hold the moving contact against the normally closed contact.

The magnets, due to their negative spring rate efie'ct on the armature, establish an unstable system which provides snap action. By properly selecting and adjusting the magnets, a switch can be designed to give almost any desired characteristic. In a sensitive switch for instrument use, the work input should be minimized. To produce rapid armature acceleration and fast contact break, the magnet force should drop rapidly as the armature moves away from it. This effect is produced by using small magnets and by having the armature approach them very closely. As the air gap of a magnet and armature is decreased, the rate of change of force with distance becomes increasingly great.

My invention provides a switch that has a low force differential and is highly resistant to vibration eliects.

My invention can be utilized wherever a snap switch with low force differential characteristics is desired.

Therefore an object of my invention is to provide a switch of the type described that is simple in construction, light in weight and reliable in operation.

Another object of my invention is to provide a snap switch with a low force differential.

Yet another object of my invention is to provide a snap switch that is highly resistant to vibration effects.

Other objects and advantages of my invention will in part be obvious and in part be described when the following specification is read in conjunction with the drawings in which:

Figure 1 is a sectional elevation of the switch, and

Figure 2 is a fragmentary plane view of the U-shaped member, torsion wire, and lever arm.

Referring now to the drawings, a U-shaped member 11 of electrical conducting and mechanically resilient material is attached to a casing 12 or dielectric material by screws 13 and nuts 14. U-sha'pe'd member 11 is within the inner chamber 15 of casing 12. A torsion wire 18 passes through holes 26 and 21 in U-shaped member 11 and is attached by a soldering operation thereto. U"- shaped member 11 has a normal shape to apply a tensile force to torsion wire 18. Brackets 23 and 24 are attached to U-shaped member 11 at 25 and 2h. Brackets 23 and 24 have slots of slightly greater width than the diameter of wire 13. The torsion wire 18 passes through the slots in brackets 23 and 24 but does not engage them in normal switch operation. The guide brackets 23 and 24 offer no restriction to a twisting movement of torsion wire I8 but do tend to restrict any other movement. These guide brackets reduce any v'ibr ation efiect's,

Lever arm 30 of electrical conducting material is attached to torsion wire 18 midway between the legs of U-shaped member 11. Torsion wire 18 is weaved through holes 31 and 32 in lever arm 30 and attached to lever 30 by a soldering operation. This point of attachment is at the approximate center of gravity of lever 30 and is the fulcrum of lever 30. Movable contacts 34 and 35 are carried on the right hand end of lever 30. A pigtail connector 37 interconnects lever 30 and U-shaped member 11. Stationary contacts 39 and 40 are carried on the inner ends of members 42 and 43 of electrical conducting material screw mounted in casing 12.

Permanent magnets 45 and 46 are carried on the inner ends of members 48 and 49. Members 48 and 49 are screw mounted in casing 1-2. The left hand end of lever 30 acts as an armature 5i) and cooperates with magnets 45 and 46 to give snap action to any movement of lever 30.

An actuator 53 is movably mounted in a bushing 54 screw mounted in casing 12. Actuator 53 has an abut ment 56 that cooperates with the top of bushing 54 to limit the extent of movement downward of actuator 53 in bushing 54. There is a snap ring 58 on the lower portion of actuator 53 that cooperates with the bottom of bushing 54 to limit the extent of upward movement of actuator 53 in bushing 54. A compression spring 60 is in between actuator 53 and lever 30. There is a socket 61in the bottom of actuator 53 to receive one end of spring 6% and a depression 62 in lever 30 to receive the other end of spring 6%. Depression 62 in lever 30 is displaced from the fulcrum of lever 30.

In this embodiment of my invention the switch is shown with a normal position of movable contact 34 engaging stationary contact 39. Lever 30 is biased to this position by a twisting moment in torsion wire 18. The magnetic influence of magnet 46 on. the armature portion 50 of lever 39 helps maintain constant contact pressure between contacts 34 and 39. A force on. actuator 53 is stored in compression spring 60 until that force becomes suilicient to overcome the influence of magnet 46 and the twisting moment in torsion wire 18. At this point lever 30 snaps to the position where contacts 35 and 40 are engaged. This snap action is due "to the rapidly decreasing effect of magnet 46 andthe rapidly increasing effect of magnet 45 on armature S0, and also the stored force in spring 60. Upon release of this force on actuator 53 the clockwise twisting moment in the torsion wire 18 is greater than the influenceof magnet '45 on armature 51 which causes contacts 35 and 40 to break and contacts 34 and 3% to make. The breakingv of contacts 35 and 40 is a snap action due to the rapidly decreasing effect of magnet 45 and the rapidly increasing efiect of magnet 45. Cover plate 54 is attached to casing 12 by screws 65.

By adjusting the position of member 42 in the casing the normal position of the lever can be varied to get the desired amount of torsion in 'wire is. The relative spacing of contact carrying members 42 and 43 as well as the relative spacing of magnets 45 and 46 can be adjusted to arrive at the desired differential. Therefore my switch has many and varied useful applications.

Various changes obviously could be made in the described embodiment of the invention without departing from the basic inventive concept. The scope of the invention is to be limited only by the appended claims.

I claim as my invention:

1. A snap-acting switch including in combination a casing with an inner chamber, a U-shaped member within said chamber attached to said casing, a torsion wire suspended across said U-shaped member near the ends of the legs of said 'U-shaped member, said 'U-shaped member exerting a -tensile force on said torsion wire, a lever arm mounted near its center at the center of said torsion wire, the fulcrum of said lever being established by said torsion wire, movable contacts mounted on opposite sides of a first end of said lever, stationary contacts mounted in said casing and disposed on opposite sides of said first end of said lever to cooperate with said movable contacts, said torsion wire biasing said lever to a normal position in engagement with one of said stationary contacts, magnets mounted in said casing on opposite sides of the second end of said lever and in spaced relation thereto, said second end of said lever acting as an armature, said magnets cooperating with said second end of said lever to provide snap action of said lever, an actuator movable in said casing, a compression spring between said lever and said actuator to apply a force to said lever on a line displaced from said fulcrum, suificient force on said actuator causing said lever to snap from said normal position to engage the other stationary contact.

2. A snap-acting switch including in combination, a frame, a U-shaped member attached to said frame, a torsion wire suspended across said U-shaped member near the ends of the legs of said U-shaped member, said U-shaped member exerting a tensile force on said torsion wire, a lever arm mounted near its center at the center of said torsion wire, the fulcrum of said lever being established by said torsion wire, guides between said lever and said U-shaped member attached to said U-shaped member restricting other than a twisting movement of said torsion wire, movable contacts mounted on opposite sides of a first end of said lever, stationary contacts mounted on said frame and disposed on opposite sides of said first end of said lever to cooperate with said movable contacts, said torsion wire biasing said lever to a normal position in engagement with one of said stationary contacts, magnets mounted on said frame on opposite sides of the second end of said lever and in spaced relation thereto, said second end of said lever acting as an armature, said magnets cooperating with said second end of said lever to provide snap action on said lever, an actuator movable in said frame, a compression spring between said lever and said actuator to apply a force to said lever on a line displaced from said fulcrum, sufficient force on said actuator causing said lever to snap from said normal position to engage the other stationary contact.

3. A snap-acting switch including in combination, a casing with an inner chamber, a torsion wire suspended across said chamber, a means for attaching said torsion wire to said casing and exerting a tensile force on said torsion wire, a lever arm mounted near its center at the center of said torsion wire, the fulcrum of said lever being established by said torsion wire, movable contacts mounted on opposite sides of a first end of said lever, stationary contacts mounted in said casing and disposed on opposite sides of said first end of said lever to cooperate with said movable contacts, said torsion wire biasing said lever to a normal position in engagement with one of said stationary contacts, magnets mounted in said casing on opposite sides of a second end of said lever acting as an armature, said magnets cooperating with said second end of said lever to provide snap action of said lever, an actuator movable in said casing, a compression spring between said lever and said actuator to apply a force to said lever on a line displaced from said fulcrum, sufficient force on said actuator causing said lever to snap from said normal position to engage the other stationary contact.

4. A snap acting mechanism including in combination a frame, a torsion wire suspended in said frame, a lever arm mounted near the center of said torsion wire, the fulcrum of said lever being established by said torsion wire, stops mounted in said frame and disposed on opposite sides of a first end of said lever to cooperate with said lever, said torsion wire biasing said lever to a normal position in engagement with one of said stops, magnetic means mounted in said frame with opposing poles on opposite sides of .a second end of said lever and in spaced relation thereto, said second end of said lever acting as an armature, said magnetic means cooperating with said second end of said lever to provide snap action in said lever, an actuator movable in said frame, said actuator engaging said lever on a line displaced from said fulcrum, sufficient force on said actuator causing said lever to snap from said normal position to engage the other stop.

5. A snap acting mechanism including in combination, a frame, a torsion wire suspended across said frame, means of attaching said torsion wire to said frame, a lever arm mounted at its center of gravity at the center of said torsion wire, the fulcrum of said lever being established by said torsion wire, stops mounted on said frame and disposed on opposite sides of said first end of said lever to cooperate with said first end of said lever, said stops being adjustable in position, a normal position of said lever determined by one of said adjustable stops, magnetic means mounted on said frame with opposing poles on opposite sides of the second end of said lever in spaced relation thereto, said second end of said levcr acting as an armature, said magnetic means cooperating with said second end of said lever to provide snap action of said lever, actuating means movable in said frame, said actuating means including spring means adapted to apply forces to said lever on a line displaced from said fulcrum, sufi'icient force on said actuating means causing said lever to snap from said normal position to engage the other of the stops.

6. A snap acting switch including in combination a frame, a torsion wire suspended in said frame, a means of attaching said torsion wire to said frame exerting a tensile force on said torsion wire, a lever arm mounted near its center at the center of said torsion wire, the fulcrum of said lever being established by said torsion wire, a movable contact mounted on one side of one end of said lever, a stationary contact mounted in said frame disposed to cooperate with said movable contact, a magnet mounted in said frame in spaced relation to a second end of said lever, said second end of said lever acting as an armature, said magnet cooperating with said second end of said lever to provide snap action of said lever, a normal position of said lever with said movable contact in engagement with said stationary contact and said magnet cooperating with said armature, an actuator movable in said frame, a compression spring between said lever and said actuator to apply a force to said lever on a line displaced from said fulcrum, sufficient force on said actuator causing said lever to snap from said normal position away from said stationary contact.

7. A snap acting switch including in combination a frame, a torsion member mounted in said frame, a lever arm mounted near its center at the center of said torsion member, a contact on the first end of said lever, a stationary contact mounted in said frame to cooperate with said movable contact, magnetic means mounted in said frame in spaced relation to a second end of said lever, said second end of said lever acting as an armature, said magnetic means cooperating with said armature to provide snap action of said contacts, a resilient actuator movable in said frame, said actuator engaging said lever upon a force applied thereto causing said lever to move With snap action.

8. A switch including in combination a frame, a torsion member mounted in said frame, a lever arm mounted near its center at the center of said torsion member and supported thereby, a contact on the first end of said lever, a stationary contact mounted in said frame to cooperate with said movable contact, magnetic means mounted on said frame in spaced relation to a second end of said lever, said second end of said lever acting as an armature.

9. snap acting switch including in combination a.

casing with an inner chamber, torsion wire suspended across said chamber, means for attaching said torsion wire to said casing, a lever arm mounted at its center of gravity at the center of said torsion wire, the fulcrum of said lever being established by said torsion wire, movable contacts mounted on opposite sides of a first end of said lever, stationary contacts mounted in said casing disposed on opposite sides of said first end of said lever to cooperate with said movable contacts, each of said stationary contacts being adjustable in said casing, said torsion wire biasing said lever to a normal position in engagement with one of said stationary contacts, magnets mounted in said casing on opposite sides of the second end of said lever and in spaced relation thereto, each of said magnets being adjustable in said casing, said second end of said lever acting as an armature, said magnets cooperating with said second end of said lever to provide snap action of said lever, an actuator movable in said casing, a compression spring between said lever and said actuator to apply a force to said lever on a line displaced from said fulcrum, sufficient force on said actuator causing said lever to snap from said normal position to engage the other stationary contact.

10. A snap acting mechanism including in combination, a casing with an inner chamber, a U-shaped member within said chamber attached to said casing, a torsion wire suspended across said U-shaped member near the ends of the legs of said U-shaped member, said U-shaped member exerting a tensile force on said torsion wire, a lever arm mounted at its center of gravity at the center of said torsion wire, guides between said lever and said U-shaped member attached to said U-shaped member for restricting other than a twisting movement of said torsion wire, the fulcrum of said lever being established by said torsion wire, stops mounted on said casing and disposed in opposite sides of a first end of said lever to cooperate with said first end of said lever, said torsion wire biasing said lever to a normal position in engagement with one of said stops, a magnetic means mounted in said casing with opposing poles on opposite sides of the second end of said lever and in spaced relation thereto, said second end of said lever acting as an armature, said magnetic means cooperating with said second end of said lever to provide snap action of said lever, an actuator movable in said casing, a compression spring between said lever and said actuator to apply a force to said lever on a line displaced from said fulcrum, sufiicient force on said actuator causing said lever to snap from said normal position to engage the other stop.

11. A snap acting switch including in combination a frame, a U-shaped member attached to said frame a torsion member suspended across said U-shaped member near the ends of the legs of said U-shaped member, said U-shaped member exerting a tensile force on said torsion member, a lever arm mounted near its center at the center of said torsion member, the fulcrum of said lever being established by said torsion member, movable contacts mounted on opposite sides on the first end of said lever, stationary contacts mounted in said frame and disposed on opposite sides of said first end of said lever cooperate with said movable contacts, said torsion member biasing said lever to a normal position in engagement with one of said stationary contacts, magnets mounted in said frame on opposite sides on the second end of said lever in spaced relation thereto, said second end of said lever acting as an armature, said magnets cooperating with said second end of said lever to provide snap action of said lever, an actuator movable in said casing, a compression spring between said lever and said actuator to apply a force to said lever on a line displaced from said fulcrum, sutiicient force on said actuator causing said lever to snap from said normal position to engage the other stationary contact.

12. A snap acting switch including in combination a frame, a U-shaped member mounted in said frame, a torsion member suspended across said U-shaped member near the ends of the legs of said U-shaped member, said U-shaped member exerting a tensile force on said torsion member, a lever arm mounted near its center at the center of said torsion member, the fulcrum of said lever being established by said torsion member, stops between said lever and said U-shaped member attached to said U-shaped member for restricting other than a twisting movement of said torsion member, movable contacts mounted on opposite sides of the first end of said lever, stationary contacts mounted in said frame and disposed on opposite sides of said first end of said lever cooperate with said movable contacts, magnets mounted in said frame on opposite sides of the second end of said lever in spaced relation thereto, said second end of said lever acting as an armature, said magnets cooperating with said second end of said lever to provide snap action of said lever, a resilient actuator acting on said lever on a line displaced from said fulcrum, suflicient force on said actuator causing said lever to snap from one to the other of said stationary contacts.

13. A snap acting switch including in combination a frame, a U-shaped member attached to said frame, a torsion member suspended across said U-shaped member near the ends of the legs of said U-shaped member, said U-shaped member exerting a tensile force on said torsion member, a lever arm mounted at its center of gravity at the center of said torsion member, the fulcrum of said lever being established by said torsion member, stops between said lever and said U-shaped member attached to said U-shaped member for restricting other than a twisting movement of said torsion member, movable contacts mounted on opposite sides of the first end of said lever, stationary contacts mounted in said frame and disposed on opposite sides of said first end of said lever to cooperate with said movable contacts, each of said stationary contacts being adjustable on said frame, said torsion member biasing said lever to a normal position in engagement with one of said stationary contacts, a magnetic means mounted in said frame in cooperation With a second end of said lever and in spaced relation thereto, said magnetic means being adjustable on said frame, said second end of said lever acting as an armature.

References Cited in the file of this patent UNITED STATES PATENTS 547,537 Biddle et al Oct. 8, 1895 802,480 Seeley Oct. 24, 1905 1,661,348 Grundman Mar. 6, 1928 2,422,861 Skrobisch June 24, 1947 2,452,425 Berkholder Oct. 26, 1948 2,614,184 Robinson Oct. 14, 1952 2,641,664 Knutson June 9, 1953 FOREIGN PATENTS 404,528 Great Britain Jan. 18, 1934

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Referenced by
Citing PatentFiling datePublication dateApplicantTitle
US2895026 *Apr 26, 1957Jul 14, 1959Gen Motors CorpSwitch operating means
US2905785 *Jul 8, 1957Sep 22, 1959Quinn Frederic RElectric switch
US2943165 *Oct 10, 1958Jun 28, 1960Oak Mfg CoElectric switch
US3056001 *Mar 10, 1959Sep 25, 1962Oak Mfg CoElectric switches
US3084312 *Jan 26, 1960Apr 2, 1963Keelavite Co LtdRelay apparatus
US3109908 *Sep 16, 1960Nov 5, 1963Gen Motors CorpMagnetically operated electric switch
US3123688 *Apr 24, 1959Mar 3, 1964 erickson
US3202783 *Feb 16, 1962Aug 24, 1965Hazemeijer CoSwitch with pole plates having a separation of non-magnetizable material
US3713055 *Jun 25, 1971Jan 23, 1973Cutler Hammer IncAuxiliary contact system for electromagnetic switching devices
US4499345 *Nov 19, 1982Feb 12, 1985Sds-Elektro G.M.B.H.Magnetic snap switch
US6707371Aug 26, 2002Mar 16, 2004Honeywell International Inc.Magnetic actuation of a switching device
US6720852Aug 26, 2002Apr 13, 2004Honeywell International Inc.Methods and apparatus for actuating and deactuating a switching device using magnets
US6741158Jul 18, 2002May 25, 2004Honeywell International Inc.Magnetically sensed thermostat control
US7026898Feb 2, 2004Apr 11, 2006Honeywell International Inc.Magnetic actuation of a switching device
Classifications
U.S. Classification200/404, 335/207
International ClassificationH01H5/00, H01H5/02
Cooperative ClassificationH01H5/02
European ClassificationH01H5/02