US2359075A - Circuit controller - Google Patents

Description

Sept 25, 1944 a E. ARNOLD 2,359,1075

CIRCUIT CONTROLLER Filed Aug. 26, 1942 @was WITNESSES: 9/

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Patented Sept. 26, 1944 cmomroonl'raouna EdwinEAmPittsblrghPa.,a-ignortof Westinghouse Bast Pittsburgllfla., eorporati ma on o Pennsylvania Com- ` spnuentlnn anni zo, 194s, serial No. 456,194 reclaim. (ci. zot-sv) This invention relates to electric circuit ccntrollers generally, and, more specifically, to',

switches which may be automatically actuable.

Certain types of switches, such as limit switches, are required to be responsive to a small amount of movement by an actuating member to provide a relatively large separation of the switch contacts suilllcientV to interrupt the circuit. This may be done by providing movement-multiplying means between the actuating member and contacts, or a simpler method is to use a switch blade member which is deformed so as to have certain initial stress set up therein, such as that disclosed and claimed in my copending application for Circuit controllers, Serial No, 393,330, led May 14, 1941, and assigned to the same assignee as this application. This type of switch wherein the actuating member directly engages the switch blade to iiex the blade for actuating the switch, not only has the advantage of simplicity, but also has certain other advantages due to the fact thatthe blade may be of bimetal so as to be automatically operable in response to predetermined thermal conditions.

One object of this invention is to provide a switch of the iiexingblade type, having a novel type of switch blade.

Another object of this invention is to provide a novel switch of the type described having a blade which flexes laterally of the direction of the application of theoperating iorce thereto, to open and close the circuit.

Another object of this invention is to provide for a switch'oi the ilexing blade type, a novel blade element vwhich is normally free of any internal stress.

Another object of this invention is to provide in a switch of the type described, a novel operating element which is responsive to predetermined thermal conditions for automatically 4actuating the switch.

Another object of this invention is to provide a novel switch normally manually operable to make on set of contacts and automatically operable t make another set of contacts, wherein upon automatic operation, attempted manual operation will not oppose making said other set of contacts. v

Still another object of,this invention is to provide a novel electric circuit controller which is txtremely simple in design, yet emcient in opera- These and other objects of this invention will become more apparent upon consideration of the bodiments thereofv when taken in connection with I the attached drawing, in which:

mure 1 is n longitudinal sectional view of nv switch casing for a switch constituting this invention, with the parts of the switch within the casing shown in elevation; y

Fig. 2 is a top plan view of the switch shown in Fig. 1 slightly modified in form and with the casing cover removed;

Fig. 3 is a view similar to Fig. 2 ota slightly modiiled form of switch;

Fig. 4 is also a view like Fig. 2, but showing the switch blade at a different normal position; and

Fig. 5 is a transverse section of the switch shown in Fig. 4 and takemsubstantially on the line V-V thereof with the cover in place; I

Preferably, the switch constituting this invention is mounted within a casing having a bottom wall 2, end walls 4, side walls B and an open topadapted to be closed by the cover I which may be removably secured to the casing in any desired manner. The switch easing is preferably formed y `oi.' a molded insulating material, although any desired type of insulating material may hegemployed. A plurality of holes are formed in the bottom wall of the switch casing for the reception of terminal .bolts It, Il and i6, arranged as shown. Each terminal bolt is provided with a nut 2t to secure itin ilxed relation with respect to the bottom wall of the casing, and a nut I-8 for securing. a line conductor thereto. Barriers 48 and l! integral with the bottom wall of the casing are preferably provided between the terminal bolts.

A switch blade 22 is supported longitudinally within the switch casing, and this blade may be formed of any desired flexible and resilient conducting material such for example as a copper alloy. As shown in Fig. 1, switchblade 22 is provided with a longitudinally extending slot 24 extending from one end of the blade to a point adjacent but spaced from the opposite end of the blade, so that the resulting construction is substantially U-shaped in form, providing spaced leg portions 26 and 28. The head Il of terminal bolt I0 is seated on a raised portion 3i of the bottom wall of the casing and is slotted as shown in Fig. 5, to receive the free end of blade leg 26 which is secured in the slot in any desired manner such as, for example, by welding or the like. l

Switch housing cover I is provided with an aperture l2 provided in alignment with switch blade 22 adjacent the free ends of the leg portions following detailed description of preferred emthereof, for slidably receiving the shank portion of an operating plunger member 34. The plunger 34 is provided with a push button 36 at the outer end thereof,'and with a slotted head 38 adapted to fit over the confronting edge of leg portion 28 of blade 22 adjacent the outerl end thereof. Leg portion 28 of the switch blade is preferably freely received in the slot of plunger head 38 so that relative sliding movement of the leg portion 28 may'occur.

With the structure thus far described, it will be observed that blade 22 is relatively rigid with respect to forces Aexerted on it in the plane of the blade, but because it is of relatively thin material which is exible and resilient, it will be readily bendable by forces exerted at an angle to the plane ofthe blade. Accordingly, when push but-` ton 35 is depressed to force the free end of leg portion 2d of the blade towards leg portion 26, the` entire outer peripheral edge of the blade, except for the free end edges of leg portions 2b and 28, will be subjected to a tensile stress and the inner edges of leg portions 26 and 28 will be subjected to compressive stress. These opposing forces will deform the blade, and since the blade is ilexible with respect to forces exerted at an angle to the plane of the blade, the deformation takes the form ,of lateral bending of the blade to the dotted line position shown in Fig. 2. It has been found that the lateral deflection of blade end il (as shown in dotted lines in Fig. 2) is much greater than the movement of plunger 3b required to produce it, so that but a relatively small movement of operating plunger Sli will produce a relatively large deflection of contact end li ofthe blade.

It will be observed that switch blade 22 is quite simple in construction and can be made by merely punching or cutting slot 2li therein. Since this is not a precision operation, the resulting blade will not be perfectly dat, and the direction in which the contact end il of the blade will defiect upon a force exerted Iby plunger Sli in a direction to bring the outer ends of leg portions 26 and 2d together, may be to either side depending upon the direction the ends of either or both of the leg portions deviate from a plane surface. Blade 22 may be mounted and tried in order to' make sure contact end il d'eects in the proper direction upon deiecticn of push button 3S, or the direction of deiiection may be predetermined by purposely slightly bending at least one of leg portions 26, 28 so that it is concave in the direction in which it is desired that the deiiection take place, so that the tensile stress on the outer blade edges due to depression of button Sii will cause further bending of the bent leg to increase the concavity thereof.

This deiecting characteristic of a switch blade like the blade 22, may be taken advantage oi by the provisionof terminal bolts iii and it, pro,

vided substantially at opposite sides of the contact end il of the switch blade, with contact screws El@ and i2 extending laterally through threaded apertures in the terminal bolts, respectively. Each contact screw may Ibe provided with a lock nut lill to lock the screw in any desired adjusted position relative to its respectiv terminal bolt.

The embodiment of the invention shown in Fig. 2 is identical with the structure of Fig. l., except that switch blade 22 is of bimetal construction comprising the laminated metallic sheets 5B and 52 secured together in xed relation, for example, as by welding or the like, with one lamision than the lamination 52. In the embodiments of the invention'shown in Figs. 1 and 2, the free end of leg 28 of switch blade 22 is electrically connected with the free end of leg 26 as by a flexible shunt so that the entire switch blade is connected in series in the circuit between terminal bolts l0 and I6.

In the operation of the switches of Figs, 1 and 2, it will be apparent that switch blade 22 may be manually moved out of engagement with contact screw 42 and into engagement with contact screw lill by depressing plunger 3d, and this action may occur automatically with the switch of Fig. 2 upon the passage through the circuit between terminal bolts ID and It of currents of sufficiently high value to heat blade 22 enough to cause it to assume the dotted line position shown in Fig. 2, by reason of its Ibimetallic construction.

Upon release of pressure on push button 36,

the blade returns to the full line position shown` in Fig. 2 because of the inherent resiliency thereof. 'Upon the passage of current'l above a predetermined magnitude through the circuit between terminal bolts I0 and i4, blade 22 will be heated enough to cause it to automatically deflect -to the dotted line position, thus energizing contact screw li and terminal bolt i6 and deenergizing contact screw 42 and terminal bolt it.

The switch construction shown in Fig. 3 is exactly like that shown in Fig. 2, except that iexible connection 155 is omitted so that only leg 26 of the blade carries current. Also, it will be noted that in Fig. 3 the blade 22 is normally in engagement with contact screw lo rather than contact screw t2 as in the embodiment shown.

nation 5B having a greater coefficient of expanis in Fig. 2. In this species of the invention blade 22 is manually actuable into engagement with contact screw i2 and blade 22 will be automatically deiiected out of engagement with contact screw [i2 upon theoccurrence of predetermined overload currents between the circuit and terminal bolt Hi which are great enough to cause heating of the blade. Accordingly, even though the circuit to contact screw @i2 is closed upon an overload,v it will be automatically opened even though pressure is maintained on push button 36, to thereby prevent damage to any apparatus in this circuit. By arranging the blade so that it will deiiect on heating in the opposite direction, the circuit between terminal bolts ill and iii will be automatically opened on an overload.

A feature of the operation of switch blade 22 when made of bimetallic construction, is that even though the blade is constructed to cause deflection of contact end il in one direction upon depression of the push button 3B, and upon heating the blade dedects in the oppositedirection as in the embodiment of the invention shown in Fig. 3, nevertheless after heating of the blade to cause it to bend in the opposite direction, the continued exertion of ra force on push button d@ will then tend to hold contact end ii of the blade in the position to which it has been moved by the heating of the blade. The reason for this is that pressure on push button 36 may move the contact end or" the blade il in either lateral direction, dependent only upon which direction any slight curvature may be initially set up in the blade. Accordingly, when the blade is bent by heating thereof, pressure on push button 36 will move it only in the direction in which it is bent, because this bending of the blade due to heat will be much greater than any slight irregularity formed in the blade during its manufacture.

Consequently, irrespective of which direction the blade contact end l1 is normally deflected by pressure on push button It, pressure on the push button after the blade has deectedbecause ofthe heating. thereof will only tend to hold the blade contact end I1 in the position to which it was moved because of the heatingleifect.

The switch illustrated in Fig. 4 is identical with that shown in Figs. 1l and 2, except that the normal position of the switch blade 22 is intermediate contact screws'l and 42, and another terminal I2 is provided connected by a flexible connection 46 to leg 2l of the blade. In the operation of this embodiment of the invention, the arrangement is such that depression of push button 36 will actuate blade contact end I1 into engagement with contact screw 42, and heating of blade 22 will causeit to engage contact screw 40. Accordingly,` the circuit to contact screw 42 and terminal bolt Il is manually controllable, and the circuit tocontact screw 4l and terminal bolt I8 is closed only upon the existenceof predetermined overload conditions in the circuit through terminal bolts I and I2.

y In the foregoing, there has been disclosed a simplified switch utilizing a blade of simple form for eiliciently transforming relatively small of said leg portions tg said support, actuating means freely movably mounted on said support and adapted when moved in one direction to exert a force on the other of said leg portions in a direction to move it towards said one leg portion to thereby cause a lateral deflection of the other end of said blade, a contact mounted on .said support laterally adjacent said other end of the blade so as to be engaged thereby upon said lateral deflection of the blade, and said blade normally occupying a position spaced from said contact.

4. In a switch, a supportLa bimetallic switch as to be engaged thereby upon said lateral deamounts of movement of a switch operating' member to relatively large movement of the switch contact'. As previously stated, the blade may or may not be of bimetallic construction, and when of bimetal it has certain novel cooperation with the manual operating means. The versatility of a switch of this type is demonstrated by the four variations illustrated. It should also be understood that many otherV arrangements could be made within the scope of the invention. Thus both contact bolts I4 and I6 need not be connected to circuits to be controlled, in which event the unused contact bolt could merely serve as a stop for the blade, and where the blade is of bimetal, separate heating means could be provided if desired.

Having described preferred embodiments of the invention as required by the patent statutes, it is desired that this invention be not limited to these particular embodiments, but that only such limitations be applied to the following claims as are required by the prior art.

I claim as my invention:

l. In a switch, a support, a switch blade, a longitudinally extending slot in said blade, means securing said blade to said support at one side of said slot and actuating means freely slidably mounted on said support for exerting a force on` said blade at the other side of said slot in a. direction to cause a variation in the width of said slot, whereby to cause longitudinal bending of said blade.

2; In a switch, a support, a switch blade, a longitudinally extending slot in said blade opening to said one end thereof, means securing `said blade to said support at one side of said slot adjacent said one end of the blade and actuating means freely slidably mounted on said support for exerting a force on said one end of said blafde at the other side of said slot in a direction to cause a variation in the width of said slot, whereby to cause longitudinal bending of said blade and lateral deiiection of the other end of said blade.

3. In a switch, a support, a resilient switch.

blade having a longitudinally extending slot opening to one end thereof to form spaced leg portions, means securing the outer end of one lit) fiection of the blade, and said blade arranged to automatically move said other end thereof into engagement with 'said contact in response to predetermined heating thereof.

5. In a switch, a support, a switch blade having a longitudinally extending slot opening to one end thereof to form spaced leg portions, means securing one of said leg portions to said support, actuating means freely movably mounted on said support for exerting a force on the other of said lag portions in a direction to cause a variation in the space between said leg portions and thereby cause a lateral deilection of the other end of said blade, spaced contacts mounted on said support at laterally opposite sides of said other end of the bla-de, said blade normally engaging one of saii contacts and flexing under the influence of sad force applying-.means out of engagement with said one contact and into engagement with the other of said'contacts.

6. In a switch, a support, a bimetallic switch blade having a longitudinally extending slot opening to one end thereof to form spaced leg portions, means securing one of said leg portions to said support, actuating means for exerting a force on the other of said leg portions in a direction to move it towards said one leg portion to thereby cause a lateral deflection of the other end of said blade, spaced contacts mounted on 7. Inra switch, a support, a bimetallic switch blade having a longitudinally extending slot -opening to one end thereof to form spaced leg portions, means securing one of said leg portions to said support, actuating means for exerting a force on the other of said leg portions in a direction to move it towards said one leg portion to thereby cause a lateral deiiection of the other end of said blade, spaced contacts mounted on said support at laterally opposite sides of said other end of the blade, said blade normally positioned between said contacts and flexing in opposite directions under the influence of said force applying means and predetermined heating thereof to engage said contacts, respectively.

8. In a switch, a support, a plurality of terminals on said support, a bimetallic switch blade having a longitudinally extending slot opening to one end thereof to form spaced leg portions, means securing one of said leg portions to one of said terminals, flexible conductor meansconnecting the other of said leg portions to another of said terminals, actuating means for exerting a force on the other of said leg portions in a direction to moveit towards said one leg portion to thereby cause a lateral deectiorrof the other end of said blade, and a contact mounted on a third terminal located laterally adjacent said other end of the blade so as to be engaged thereby upon said lateral deflection of the blade by said force-applying means or by-automatic lateral de'- ection in response to predetermined conditions in the circuit through said rst two terminals.

9. Ina switch, a support, a plurality of terminals on said support, a bimetallic switch blade having a longitudinally extending slot opening to one end thereof to form spaced leg portions,

means securing one of said leg portions to one f of said terminals, exible conductors connecting the other of said'leg portions to another of said terminals, actuating means for exerting a force on the other of said leg portions in a direction to move'it towards said one leg portion to thereby cause a lateral deilection of the other end of said blade, spaced contacts mounted on others of said terminals, respectively, and positioned at laterally opposite sides of said other end of the blade, said blade normally positioned between said contacts and ilexing in opposite directions under the inuence of said force applying means and predetermined conditions of the circuit through said rst two terminals to engage said contacts, respectively.

10. In 'a switch, a support, a plurality of terminals on said support, a bimetallic switch blade having a longitudinally extending slot opening to one end thereof to form spaced leg portions, means securing one of said leg portions to one of said terminals, actuating means for exerting a force on the other of said leg portions in a direction to move it toward said one leg portion to thereby cause a lateral deection of the other end of said blade, spaced contacts mounted on others of said terminals, respectively, and positioned at laterally opposite sides of said other end of the blade, said blade normally engaging one of said contacts `and flexing under thel inuence of said force applying means out of engagement with said one contact and into engagement with the other of said contacts, and said blade automaticallyA responsive to predetermined of said leg portions secured to the bottom wall` conditions in the circuit through said first terminal 'and one contact to move out of engagement with said one contact into engagement with the other of said contacts. y v

11. A switch supporting housing, a switch blade in said housing, said blade having a longitudinally extending slot opening to one end thereof to form spaced leg portions, one of said leg portions secured to one inner wall of said housing, actuating means freely slidably mounted through the opposite wall of said housing and engageable with the other of said leg portions to cause said other leg portion to be moved towards the other and thereby produce lateral deflection of the other end of said blade, and contact means in said housing cooperating' with said other end of the blade to open and close the circuit responsive to deection of said blade.

l2. A switch supporting housing having an open side, a cover for said open side of the hous- I ing, a switch blade in said housing, said blade having a longitudinally extending slot opening to one end thereof to form spaced leg portions, one

of said housing, actuating means freely slidably mounted through the cover of said housing and engageable with the other of said leg portions to cause said other leg portion to be moved towards the other and thereby produce lateral'deflection of the other end of said blade, and contact means in said housing cooperating with said other end of the blade to open and close the circuit responsive to deection of saidblade.

13. In a switch, a support, a switch blade having a longitudinally extending slot in said blade, means securing said blade to said support at one side of said slot, actuating means movably mounted on said support for exerting a force on said blade at the opposite side of said slot in a direction to cause a variation in the width of said slot, whereby to cause longitudinal bending of said blade, and said blade being normally free ed on said support for exerting a force on said said blade, and said means being the sole means.

for actuating said blade by the application of external force.

vEDWIN E. ARNOLD.

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