US2246183A - Electric switch - Google Patents

Description

June 17, 17941. Q P, PEPPER 2,246,183

' ELECTRIC SWITCH Filed May 4,v 1959 Figi Figli.

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Patented June 17,' 1941 UNITED STATES PATENT OFFICEy 2,246,183 ELECTRIC SWITCH Carl P. Pepper, Fort Wayne, Ind., assignor to General Electric Company, a corporation of New York Application May 4, 1939, Serial No. 271,690

(Cl. 20D-87) 9 Claims.

'and assemble.

Y vture is mounted in the casing. This core structure comprises a number of laminations frictionally secured in a recess in the casing by a leafspring. A shading coil element encircling a portion of the core structure adjacent its pole face serves to retain an energizing winding on a leg of the magnetic core and also co-operates `with the casing for further positioning and mounting these parts in the casing, the use of complicated and expensive fastening elements being avoided.

In assembly, the core laminations are Stacked and inserted in the recess or depression in the casing. 'I'he leaf spring is then inserted into the recess beside the laminatipns to hold them j together. The energizing winding wound on a spool is placed over the leg of the core, and the shading coil element is inserted in suitable slots in the pole faces of the core to clamp the laminations together. Self-tapping screws which cooperate with the shading coil element are then screwed into the casing to ysecure and position the whole'magnetic structure.

For mounting a movable contact and an armature which cooperates with thecore structure, a

` resilient strip is provided which is secured to a terminal v member fastened in the casing. the

terminal member also serving to secure the en- Y ergizing winding in position on the core structure. The resilient strip has a trifurcated movable end comprising a pair of outer prongs and a central prong all of which extend across one face of the armature. For securing the armature.

hooked ends are provided on. the outer prongs and are inserted in apertures at one end of the armature, the amature being free for limited pivotal movement with respect to the outer prongs. i

The movable contact is carried at the end of thev central .prong and engages a xed contact, the contacts beingl arranged either normally open or normally closed as desired. With normally closed or engaged contacts, the contact pressure is substantially determined by the biasing force of the outer prongs minus the opposite biasing force of the central prong. With normally open or disengaged contacts, the `contact pressure is determined by the biasing force of the central prong alone. the contacts engaging slightly before the armature reaches its attracted position.

The operation of the relay is quiet due to the fact that the movement of the armature is restricted on one end only by the outer prongs. This allows the armature to find its own position touching both poles of the core when the coil is energized. Since the pressure holding the armature away from the core is applied by two separate prongs, the armature is free to rock sidewise a limited amount in order to align itself with the pole faces of the core. Quiet operation of the amature between its attracted and unattracted positions is enhanced by doubly biasing the armature. that is, it is biased to the unattracted position by the outer prongs and is biased to the attracted position by the central prong with a. lesser force than that provided by the outer prongs.

Further objects and advantages of my invention will become apparent from the following description and for a complete understanding of phenolic condensation product. In the my invention reference should be had to the accompanying drawing in which Fig. 1 is a plan view of a switch embodying my invention having normally closed contacts; Fig. 2 is a sectional view of the switch taken along the line 2-2 of Fig. l looking in 'the direction of thearrows; Fig. 3 is a sectional view of the switch taken along .the line 3 3 oi' Fig. 2 looking in the direction of the arrows; and Fig. 4 is a sectional view of the switch taken along line 4 4 of Fig. 2 looking in the direction of the arrows; Fig. 5 is a disassembled perspective view of certain oper- (ating parts of the switch; and Fig. 6 is a sectional view similar to Fig. 4 but showing the switch provided with normally open contacts.

Referring to the drawing, invention in one form as applied by an electrical switch of the magnetically operated type enclosed 'inacasing "which maybe made from some suitable plastic insulatingcomposition, such as, a preferred I have shown my ment of the armature with respect to its mounting is provided. The central prong 3i is not semagnetic core I4 composed of a plurality ofr laminations i5 of suitable magnetic material stacked together. The connecting portion of the U forms a substantially rectangular projection i6 adapted to be inserted into a substantially rectangular recess il in the upper wall of the casing lil. An initially deformed leaf spring i8 is also inserted in the recess ll along one side of the projection i6 to bias the stacked laminations i5 together and against a side of the recess, frictionally to secure the laminations in the recess and thereby mounting the magnetic core structure lli in the casing. The two legs of the U form the two legs i3 and 23 of the magnetic core structure i4 having the pole faces 2i at the extreme ends provided with the slots 22 therein for receiving a shading coil element 23. The inner portion of each of the legs IS and 23 is encircled by the shading coil element 23 which affects the phase angle of the magnetic flux at the corresponding portions of the pole faces 2i in a well known manner. Preferably, the shading coil element 23 comprises a at'plate stamping of non-magnetic material, such as copper, having a pair of apertures 2li for mounting the element in the slots 22 on the legs i3 and 20 of the core structure I6. Extending portions at the sides of the shading coil element 23 are provided with the screw holes 25 for receiving the self-tapping screws 26 which are threaded into the casing i0 for securing the shading coil element and the core structure in position. As`illustrated in Figs. 2 and 3, a. spool 21 of insulating material having an energizing winding 28 thereon is mounted on the leg of the core structure' in'- between the bottom of the U andthe shading coil element 23, the shading coil element retaining the spool on the leg. Y z

For` operating a movable contact 29 to engage with and disengage from a fixed contact 30, I

have provided an armature 3i of suitable magnetizable material which is resiliently supported by a resilient strip 32, preferably of conducting material, for movement from an unattracted position shown in Fig. 2 to an attracted position (not shown), when the energizing winding 28 is energized. As shown, the armature 3i `comprises a plurality of superposed laminations of magnetizable material secured together by a rivet v33 and` having at its right end a pair of apertures 33 extending therethrough. The resilient strip 32 is preferably provided with a bent portion at its. left end suitably secured,.such as by spot welding, to a terminal support 35 which extends across the casing I0 and is. fastened therein. From the vertex of the angle forming the bend in the resilient strip 32, the remaining portion thereof extending to the right is trifurcated to form a pair of outer prongs 36 and a central prong 31, in substantially parallel relationship, which extend across one face of the armature 3i for supporting and biasing it as described herebelow. The armature 3l is secured to the outer prongs 36 by means of the hooked portions 38 at their right ends which are projected through the apertures 34 and bent around the right end of the armature. In this manner, limited pivotal movecured to the armature but is free for movement relative thereto. i

The resilient strip 32 serves to support, secure and bias the armature 3|. The hooked ends 33 of the outer prongs 35 *effectively prevent any undue longitudinal or side-wise movement of the armature 3| with'respect to the pole faces 2i. The outer prongs 36 are preformed or bent to bias the armature 3i to its unattracted position shown in Fig. 2, while the central prong 3l is preformed or bent to support and bias the armature, when in its unattracted position, to its attracted position with a lesser force than the biasing force of the outer prongs, whereby the armature is held by prong 3l in place in the hooked ends 33 of the prong 36. The central prong 3i also carries at its extreme right end the movable contact 29 which, as shown in Fig. 2, is mounted for normal engagement with the fixed contact 3G, that is, normally closed contacts, when the armature 3i is in its unattracted posiltion. However, as seen in Fig. 6, these contacts- 29 and 30 may be respectively placed to provide normally disengaged contacts, that is, normally open contacts, when the armature is in its unattracted position.

As seen in the drawing, the change from normally closed contacts to normally open contacts may easily be made by placing themovable contact 2S on the opposite side of the central prong 3l and by inverting the fixed contact 3G from its former position to a spaced apart relation for engagement by the movable contact 29, when the armature moves from the unattracted to the attracted position. When normally open contacts are provided, as illustrated in Fig. 6, a stop projection 39 is preferably utilized to determine the unattracted position of the armature and the movable contact. As shown, the stop 39 comprises a projection of vinsulating material supported by the casing -ID and adapted to engage the right end of the central prong 31 in the unattracted position of the armature.

Y As best seen in Figs. 1 and 5, the terminal support 35 comprises a body portion l0 bridged across the casing and supported on suitable posts 4i at the sides thereof and a flange portion 42 extending upwardly from the central part of the body portion providing a broad surface upon which the bent portionof the resilient strip 32 may -be secured by welding. The terminal member 35 is preferably secured to the casing by swagingover' the protruding ends of metallic inserts which are inserted in apertures in the casing. Theinsert i3 shown in Figs. 4 and 6 securing the terminal strip 44 which mounts the fixed contact 30 is illustrative. Circuit connections to suitable conductors are made by means of the screws 45 threaded into the inserts 43. The body portion 4U of the terminal member 35 also assists in securing the energizing winding 28 and spool 2l in place on the leg 20 of the core structure. V'

As viewed in Fig. 1, the circuit of the energizing winding 28 through the switch extends from the terminal member 35 through the winding 28 and to the terminal screw 45 in the upper right' hand corner of the casing, The controlled circuit through the switch extends from the terminal member 35 through the central prong'31 and the contacts 29 and 30 to the terminal strip 44 in the lower left hand corner of the casings.

In operation of the switch with normally closed contacts as shown in Fig. 2, the contact contact 30.

pressure between the engaged contacts 29 and 30 is substantially determined by the biasing force of the outer prongs 36 minus the biasing force of the central prong 31, although the weight of the armature 3l has an effect when the switch is mounted as shown. Energization ofthe magnetic core structure I4 causes the amature to move upwardly to the attracted position and disengage the movable contact 23 from the fixed With normally open contacts as shown in Fig. 6, the unattracted position is determined by the stop 39 which limits the downward movement of the central prong 31 and the movable contact 29. When the armature 3| is attracted, it moves upwardly, the movable contact 29 engaging the xed contact 30 which prevents further movement of the central prong 31 thereafter while the armature continues its upward movement to the attracted position. The contact pressure between the contacts 29 and 30 in this instance is determined by the biasing force of the central prong 39 acting substantially alone. Ineach of the above instances, the operation of the relay ls quiet due to the fact that the armature 3| is free t align itself with the pole faces 2| of the core I4 by rocking in either direction, i. e., lengthwise or sidewise.` Lengthwise movement is aiorded by pivoting of the armature Il on the hooked ends 38 of the outer prongs 36. Since the armature 3| is held by two prongs 36 and each one is free to move independently of the other, the armature can rock sidewise also to align itself with the pole faces While I have shown a particular embodiment of my invention, it will be understood, of course, that I do not wish to be limited thereto since mam modicationsimay be made, and I therefore contemplate by the appended claims to cover any such modications as fall within the true spirit and scope of my invention.

What claim as new and desire to secure by Letters Patent of the United States is:

1. An electric switch comprising switching means, a magnetic core structure, an energizing v winding on said core structure, an amature movable between magnetically attracted and unattracted positions, means biasing and supporting saidamature including a plurality of resilient strips extendingiacross one face of said amature, support means securing one end of said strips. means including al hooked end on one of said strips for securing said armature to said strip, said strip biasing said armature to said unattracted position, at least one other of said strips biasing said armature with a lesser' force to said attracted position, and vmeans including said other strip for operating said switching means. Iv y 2. An electric switch comprising switching means, a. magnetic core structure, an energizing winding cn said ccre structure, an armature movable between magnetically attracted and unattracted positions, spring means for resiliently supporting said amature including a strip of resilient material secured at one end and having a trifurcated portion at the other end comprising a certr'al prong and apair of outerprongs,

said outer prongs biasing said armature to said unattracted position, and said central prong operating said switching means and biasing said armature to said attracted position.

3. An electric switch comprising relatively xed and movable contacts, a magnetic core structure,

an energizing winding on said core structure, an 7 armature movable between magnetically attracted and unattracted positions for operating said movable contact, spring means for resiliently supporting said armature including a strip of resilient material secured at one end and having a trifurcated portion comprising a central prong and a pair of outer prongs in substantially parallel relationship, said outer prongs biasing said armature to saidunattiacted position, said iixed and movable contacts being in normal engagement when said armature is in said unattracted position, and said central prong mounting said movable contact and biasing said armature to said attracted position, the contact pressure between said contacts being substantially determined by the biasing force ci said outer prongs minus the biasing force of said, central prong on said armature.

4. An electric switch comprising relatively fixed and movable contacts, a magnetic core structure, an energizing winding on said core structure, lan armature movable between magnetically attracted and unattracted positions for operating said movable contact, spring means for resiliently supporting said armature including a biasing said armature to said unattracted position, said contacts being normally disengaged when said armature is in said unattracted position,` and said central prong mounting said movable contact and biasing said armature in said unattractive position to said attracted position with a lesser force than the force of said outer prongs, whereby the biasing force of said central prong assists the magnetic force of said core structure tending to draw the armature to said attracted position until said contacts are engaged, thereafter the contact pressure between said contacts being determined by the biasing force of said central prong.

5. An electric switch comprising a casing of insulating material, relatively Ilxed and movable contacts, a magnetic core structure mounted in said casing, an energizing winding on said core structure, an amature movable between magnetically attracted and unattracted positions for operating said movable contact, a fixed terminal member mounted in said casing having a portion serving as a support and another portion for-securing said energizing winding on said core structure, spring means for resiliently supporting said armature including a strip of resilient' material having one end secured to said terminal support and having a trifurcated portion at its other end comprising a central prong and a pair vof outer prongs in substantially parallel relationship, said outer prongs biasing said armature to Vsaicl unattracted position, and said central prong operating said movable contact and biasing said armature when in said unattracted position to said attracted position.

6. An electric switch comprising a casing of insulating material, relativelyl fixed and movable contacts, a magnetic core structure secured in said casing, an energizing winding on said core structure, an armature movable between magnetically attracted and unattracted positions for operating said movable contact, a terminal member mounted in said casing and having a portion serving as a support, spring means for resiliently supporting said armature includinga strip of resilient material secured at one end to said terminal support and having a trifurcated portion at its other end freely movable and comprising a central prong and a pair of outer prongs in substantially parallel relationship, means including a hooked end portion on each of said outer prongs and co-operating apertures in said armature for securing said armature to said outer prongs, said outer prongs biasing said armature to its unattracted position, and said central prong operating said movable contact and biasing said armature to said attracted position.

'1. The combination with an electric switch of the magnetically operated type of a casing of insulating material having a recess in a wall thereof, a magnetic core structure including a plurality of laminations provided with a leg porstructure adjacent said pole face, means including a portion of said shading coil element for additionally securing and positioning said core structure in said casing, a fixed terminal member mounted in said casing and having a portion serving as a support, said shading coil element and said terminal member securing said energizing winding on said leg portion of said core structure, relatively fixed and movable contacts, an armature movable between magnetically attracted and unattracted positions, spring means i'or resiliently supporting said armature including a strip of resilient material secured at one end to said terminal support and having a trifurcated portion at the other end comprising a pair of outer prongs and a central prong extending across one side of said armature in substantially parallel relation, and`means including a hooked end on said outer prongs for securing said armai laminations forming a U-shaped core member having its base inserted in said recess, resilient means in said recess applying a pressure laterally against said laminations so as to press said laminations together, the end of each arm of said U-shaped core member being provided with a pole face and with a slot extending transversely with respect to said laminations, a pole shader plate made of electrically conducting material provided with separate portions lying in said slots and with a portion extending laterally at each side of said core member, means detachably securing said extensions on said plate to said base thereby to clamp said plate and said core member to said base,said plate forming a pole shader for both pole faces of said core member, an armature, resilient means loosely supporting said armature in spaced relation with both of said pole faces, a winding on said core member secured on said core member by said pole shader plate, said winding when energized moving said armature into engagement with both of said pole faces, and switch means operated by said armature.

9. An electric switch comprising a support made of electrically insulating material provided with a rectangular recess, a plurality of stacked laminations forming a U-shaped core member having its base inserted in said recess, the end of each arm of said U-shaped core member being provided with a pole face and with a slot extending transversely with respect to said laminations, a pole shader plate made of electrically conducting material provided with separate portions 1ying in said slots and with a portion extending laterally at each side of said core member, means detachably securing said extensions on said plate to said base thereby to clamp said plate and said core member to said base, said plate forming a pole shader for both pole faces of said core member, a spring vstrip extending across said pole faces in spaced relation therewith, an armature loosely secured on said spring strip and normally held by said spring strip in spaced relation with both of,l said pole faces, and a winding on said core member secured on said core member by said pole shader plate, said winding when energized moving said armature into engagement with both of said pole faces, and switch means carried by said spring strip.

CARL P. PEPPER.

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