US3662288A - Magnetic switch system - Google Patents

Abstract

This is a magnetic switch in which a plunger urges a contact at the end of an armature against a fixed contact passing a current through the winding around the core which causes a magnetic field to be formed around the core that holds the armature to the core until the circuit is broken by another means.

Description

I United States Patent 1151 3,662,288 Carlson et al. 5] May 9, 1972 [54] MAGNETIC SWITCH SYSTEM References Cited [72] Inventors: Peter T. Carlson, Canton; Frederick J. UNITED STATES PATENTS Weremey, Milton; Edward Mitchelb 2,104,632 1/1938 Agnew ..335/l86 Mass- 1,250,746 12/1917 Wolff ..335/240 [73] Assignee'. TRW Inc., Cleveland, Ohio 2,499,082 2/1950 Wood ..335/239 d: 21 1970 [22] Flle Apr Primary Evaminer-Harold Broome PP N05 38,626 Attorney-Philip E. Parker, Gordon Needleman, James R. 0-

Related US. Application Data Connor, John Todd and Hall & Houghton [62] Division of Ser. No. 759.286, Sept. 12, 1968. [57 ST 52 U.S. c1... ..335/192 This is a magnetic Switch in which plunger urges a Contact at [51] Int. Cl. ..H0lh 50/30 the end of an armature against a fixed contact passing a cur- [58] Fiel f S h 240, rent through the winding around the core which causes a mag- 335/193 netic field to be formed around the core that holds the armature to the core until the circuit is broken by another means.

1 Claim, 2 Drawing Figures IO... 14 20- I6 56) SB g;

74 o d t x O 0 j 54 O 28 82 s4 66 I 30 lNVENTORS PETER T. CARLSON FREDERICK J. WEREMEY B) EDWARD MITCHELL PATENTEDMAY 9 1972 I ATTORNEY I MAGNETIC SWITCH SYSTEM This is a divisional of application Ser. No. 759,286 filed Sept. 12, 1968.

SUMMARY OF THE INVENTION 7 as long as current is passing through the circuit.

BRIEF DESCRIPTION OF THE DRAWING ,FIG. I is a side elevation partly in section and partly schematic showing a remote controlled release mechanism and the switch means; and

FIG. 2 is a side elevation of the armature assembly.

DESCRIPTION OF THE PREFERRED EMBODIMENT The holding switch assembly comprises a plunger 10 which is tubular-in configuration and which is open at one end and closed at the other.-A radial flange 12 extends outwardly adjacent its open end and a cylindrical nib 14 extends from the inner surface of the closed end of the plunger 10 for a purpose to be described hereinafter. The carrier 16, another component of the holding switch, has a cup-shaped portion and a cylindrical shaft portion 18 which extends axially from the bottom of the cup-shaped portion as shown in FIG. 1. The external diameter of the cup-shaped portion is less than the internal diameter of the cavity of the plunger 10. A helical compression carrier spring 20 is located within the cavity of the plunger 10 and circumscribes the nib 14. The carrier 16 is slideably engaged within the-cavity of the plunger 10 with the remaining portion of the carrier spring 20 extending into the cup-shaped portion or well of the carrier 16 and abutting the bottom thereof as shown in FIG. 1. A carrier washer 21 having an aperture therethrough is engaged to the plunger 10 and the carrier .16 by passing the shaft portion. 18 of the carrier 16 through the aperture until the carrier washer 21 butts against the shoulder formed by the bottom of the cup-shaped portion of the carrier 16 with the smaller diameter shaft portion 18 and against the internal shoulder formed in the plunger 10 as shown in FIG. 1. The ultimate holding force against the carrier washer 2I is supplied by a conical, coil plunger spring 22 which is butted against the lower surface of the carrier washer 21 and which circumscribes the shaft portion 18.

The core sub-assembly of the holding switch comprises an insulating base 28 generally rectangular in configuration which has a core blade terminal 30 passed through an aperture formed therein. A soft iron core 38 is in superposed abutting relationship to a portion of the core terminal 30 and the base 28. The core 32 comprises a rectangular solid base portion having two rectangular solid blocks one of which extends from a surface adjacent each end and another rectangular solid block which extends from the opposite surface adjacent one end as shown in FIG. 1. There are a pair of cylindrical protrusions which are used in the assembly operation as will be explained hereinafter. The armature 34 includes'a strip-like portion having an aperture centrally formed therein through which the upper contact 42 is engaged. The magnetic strip 36 is mounted ontop of the armature 34 and is held in engagement therewith by inserting the upper contact 42 through an aperture formed in the magnetic strip 36 and swedging it over. It is possible to reverse the position of the magnetic strip 36 and the armature 34 if desired. The lower end of the armature 34 and the magnetic strip 36 are free; that is, they are not physically attached together although they are in butting realtionship as shown in FIG. 1. Although we could coat the armature34 with a magnetic material or use a bi-metallic strip, the inventors have decided to utilize the bulk properties of a strip of magnetic material. Thus one of the purposes of the armature 34, which is formed of a spring steel, is -to supply spring flexibility to the comparatively soft material which forms the magnetic strip 36. The armature 34 has an arm 48 which extends from a side edge and which has a pair of spaced holes formed along its midline. The two apertures formed in the arm 48 of the armature 34 are engaged with the protrusions 40 which extend from the core 32 as shown in FIG. 2. There is a possibility that adjustment may be required in the magnetic strip 36. This contingency is provided for by bowing the strip proximate its terminal end. Adjustments can be provided by tweaking the magnetic strip near the bowed portion. It is important that the magnetic strip maintain the same shape. The wire blade terminal 50 is engaged to the base '28 in a manner well known in the art through a slot formed in the base 28.

Prior to assembling the core 32 with the base 28 and the arma- 1 ture 34. a coil of conductive wire is formed or wrapped around the core body proper and has two terminations one of which is soldered to the wire blade terminal 50. A lower contact 44 and a contact spring 52 are assembled together forming a lower contact sub-assembly. The contact spring 52 comprises a flat flexible conductive material such as spring steel which is bent to form an upper arm, a support portion at right angles to the upper arm and a lower arm at right angles to the support portion and in substantially parallel relationship with the upper arm. The lower contact 44 is engaged through an aperture formed in the upper arm of the contact spring 52 and swedged into engagement therewith and the lower arm is attached to the base by an eyelet or other appropriate attaching means. The top portion of the lower contact 44 is on a plane above the upper plane of the rectangular box-like portion of the core 32. This relationship is maintained so that the upper contact 42 will electrically engage the lower contact 44 prior to the time that the magnetic strip 36 engages the core 32. The other end of the core wire 54 is attached to the. contact spring 52 to complete its circuit.

The housing sub-assembly includes an'aluminum box-like housing 56 having an aperture formed through its cap portion. A bushing 58 formed of aluminum is curled into the aperture formed in the housing. Then the assembly of the plunger I0, the carrier spring 20, the carrier 16 and the carrier washer 21 are dropped into the bushing 58 until the flange 12 butts against the bushing 58. The plunger spring 22 would then be placed in circumscribing relationship to the shaft portion 18 with an end butted against the support washer 24 which in turn rests on the tabs 26'which extend from the side walls of the housing 56. An aperture is formed in the support washer 24 through which the shaft portion 18 of the carrier 16 can extend when the plunger 10 is depressed. The housing 56 with its subassemblies is now engaged to the base 28 with its sub-assemblies completing the total assembly of the magnetic holding switch.

Generally speaking, the switch can be considered as one which is mannually closed and electrically opened. As the plunger 10 is depressed the carrier spring 20 and the carrier 16 move down compressing the plunger spring 22. As pressure on the plunger 10 continues the shaft portion 18 passes down through the aperture in the support washer 24 until the terminal end of the shaft portion 18 bears against the magnetic strip 36. The shaft portion 18 will continue to push the magnetic strip 36, the armature 34 and the upper contact 42 toward the core 32 and the lower contact 44. When the upper contact 42 engages the lower contact 44 a circuit is completed through the core wire 54 and the core 32 exerts a magnetic force of attraction on the armature 34 and its associated magnetic strip 36. The manual force exerted by the shaft 18 of the carrier 16 continues concurrently with this magnetic force until the armature 34 physically butts against the core 32. With these two elements engaged and the circuit in operation the plunger 10 may now be released without disturbing the magnetic circuit or the switch circuit connected to the heat motor 62. To provide overtravel after the shaft 18 has engaged the fixed position of the core 32 through the armature 34 and the magnetic strip 36 the carrier spring 20 will allow the plunger to continue a short distance after this mentioned engagement.

The switch assembly is shown electrically connected to a release mechanism comprising a heat motor 62, a driving gear 72 and an actuating gear 73. The basic object of the release mechanism is to rotate a transmission shaft (not shown) which in turn will actuate a latch mechanism (not shown) thus opening a door or the like. When the heat motor 62 is activated by the holding switch assembly the heat motor shaft will start moving outwardly forcing the carrier piston 66 through the insulator 82 and one end of a support bracket 74. The carrier piston 66 circumscribes in a fixed relationship the heat motor shaft (not shown) and moves therewith. The carrier piston 66 has an integral piston arm 70 which extends outwardly at right angles therefrom and overlies the driving geat 72 which is rotatably attached to the support bracket 74 by a rivet 75. The rivet 75 makes electrical contact with the support bracket 74 and thence to ground. This means that the driving gear 72 is also connected to ground through the rivet 75. A return spring 76 is wrapped around the carrier piston 66 engaged against the insulator 82 and has its opposite terminal end flexed against the piston arm 70 holding it downwardly against the rivet 75. The return spring 76 also acts as a compression spring between the insulator 82 and an external shoulder of the carrier piston 66. Thus the return spring 76 functions both as a compression spring and as a torsion spring. The rivet 75 is headed in such a way that the piston arm 70 is spaced from the main body of the driving gear 72. A pin 78 extends at right angles from the driving gear 72 and is positioned directly in front of the forward surface of the piston arm 70. As the carrier piston 66 moves forward it compresses the return spring 76' and engages against the pin 78 rotating the driving gear 72 in a counterclockwise direction. This rotation of the driving gear 72 is translated to the meshed actuating gear 73 which rotates in a clockwise direction turning the transmission shaft (not shown) in that direction. This rotation of the driving gear 72 continues until the chamfer 84 which extends from the carrier With reference to the foregoing description it is to be understood that what has been disclosed herein represents an embodiment of the invention and is to be construed as illustrative rather than restrictive in nature and that the invention is best described by the following claims:

l. A magnetic switch comprising a plunger having a shaft portion extending therefrom, an iron core fixed to a base and spaced from the shaft portion, a contact arm comprising a flexible armature abutting a magnetic strip, the contact arm having a terminal end attached to the iron core and the free end spaced between the iron core and the shaft portion, a helical compression spring circumscribing the shaft portion and butted against the plunger and against a fixed portion, a contact portion extending from the free end and engageable with a fixed contact and an electrical wire wound about said iron core and attached to the fixed contact and to a terminal.

Claims (1)

1. A magnetic switch comprising a plunger having a shaft portion extending therefrom, an iron core fixed to a base and spaced from the shaft portion, a contact arm comprising a flexible armature abutting a magnetic strip, the contact arm having a terminal end attached to the iron core and the free end spaced between the iron core and the shaft portion, a helical compression spring circumscribing the shaft portion and butted against the plunger and against a fixed portion, a contact portion extending from the free end and engageable with a fixed contact and an electrical wire wound about said iron core and attached to the fixed contact and to a terminal.

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