US2255330A - Switch - Google Patents

Description

E. T. PLATZ Sept. 9, 1941.

"SWITCH Filed June 5, 1941 2 Sheets-Sheet l bFF TQ/PPED INVENTOR.

Sept. 9, 1941. E -z 2,255,330

SWITCH Filed June 5, 1941 2 Sheets-Sheet 2 A Fax. 6

" F v EN TOR.

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SWITCH Elwood '1. Plats, Detroih'Micln. assignmto Bulldog Electric Products Company, Detroit,

Mich, a corporation of West Virginia Application June 5, 1941, Serial No. 396,688

14 Claims. (Cl. 200-113) This application relates to switches and more particularly to switches which are manually operable, but which operate automatically for opening the circuit in the event of an overload.

A principal object of the invention is to provide a switch so compact as to enable it to be mounted in a conventional small size wall outlet box.

Another object is to provide a switch of the character described, employing a single leaf spring upon which is directly mounted a bimetal element, which provides snap-action for manual operation and in addition provides a tripping force in the event of an overload.

A further object is to provide a switch of the character described in the preceding paragraph,

wherein the contact movement on overload is For attaining these and other objects, the switches disclosed herein have been provided. These have several desirable characteristics, among which are the following:

First, they are trip free; that is to say, their overload release operation may take place whether or not the handle be held.

Secondly, in the manual actuation, there is a desirable snap-action which imparts a snapaction feeling to the hand oi. the operator through the handle.

Thirdly, no flexible conductors or loops, commonly known as pigtailsf? are employed.

Fourthly, no holding latches, releasable on overload, are employed.

The switches herein disclosed comprise two diflerent embodiments, disclosed respectively in Figs. 1 to 4 and Figs. 5 to 8. i Figures 1, 2, 3 and 4 respectively show one embodiment in closed circuit position; in section on line 2-2 of Figure 3; in open circuit position; and in overload released position.

Figures 5 to 8 respectively show another embodiment in closed circuit position; in section on line 6-4 of Figure 5; in overload released position; and in open circuit position.

Figures 1-4 The snap switch herein disclosed includes a casing H having a cover plate l2, both being 0! insulation, and pivotally mounting a rocker handle i3, whose movement is determined or limited by stops I4 and II. Pockets II and ll of the handle and easing respectively receive the end of a leaf spring ll, normally held under com.- pression to have two free or stable positions, one

on each side oi the straight line connecting 5s stationary contacts 23.

Mounted at its center point 2|, by means of riveting or welding on tothe spring II, is a bimetal element 2i, preferably, although not necessarily, of the snap-action type, such as a disk, and welded to the outer points or edge of the disk are contacts 22 which move toward and away irom stationary contacts 23 mounted in the casing.

When the element 2| is cold, it has the general shape shown in Figures land 3, but when heated, it generally is of the shape shown in Figure 4. 1

A reset stop 24 iormed on the casing ii is provided so that, though the spring may occupy either one of its positions across line "-41 when the handle is in the position of Figures 1 or 4, the spring may not occupy a position to the left or line 50/", when the handle is in the position shown in Figure 3, but will occupy only a position to the right of that line. i

The operation of the device is as follows: For manual actuation, the spring I, always remains to the right of the line lO-ll, regardless oi the position of that line with respect to line 18-", and since it is always under compression, the spring biases the handle towards the extreme positions, thus holding the handle there; also when the parts are in the closed circuit position of Figure l, the spring maintains the movable contacts 22 in pressure engagement with the As the spring is shifted by the handle across the line connecting points "-41, it moves the movable contact. towards or away from the stationary contact and at the same time moves the handle toward either 0! the two handle positions. This is the desired manual actuation and is accompanied by a desirable snap-action as well as by a snap ieeling imparted to the hand of the operator on the handle it.

The contacts 22 and 23 are so positioned that when the parts are in the closed circuit position 01' Figure l, the spring I. does not occupy its free position, such as is shown in Figure 3, but instead is slightly compressed, suiiiciently to maintain contact pressure at 22 /23.

On the arising of an overload, the bi-metal.

spring II to pass across line ll/l'l with a snap action and cause the parts to assume the position of Figure 4, the handle remaining stationary.

For resetting, it is merely necessary to rock the handle to the open circuit position of Figure 3. Spring l8, will be carried with the handle and as it reacts on stop 24 will be returned to its position. A design of this character will give a relatively larger degree of contact opening travel when the circuit is opened, as an overload, considerably greater than would be the case if no such design were adopted. In addition, a design of this character will provide a snap-action during the movement of the contact from the closed circuit position of Figure l to the overload release position of Figure 4.

The bi-metal 2| is preferably of the snap-action type, such as a disk. This type of element provides for movement of the part with a snapand the bi-metal element does not linger in any intermediate position. However, a bi-metal element which is not of the snap-action type may be employed thought with not so great a degree of satisfaction as would be the case if the bimetal were of the snap action type.

Figures 5 to 8 The circuit breaker or switch herein disclosed comprises a casing including complementary parts 30 and 3i, and containing a handle 32 oi insulation, secured by means of screws or the like to arms 33, in turn fastened to a shaft 34, joumalled in pockets 35 moulded in the casing. Pockets 36 a'nd 31 in the shaft and handle respectively seat a leaf spring 38 under compres sion between the pockets and this spring has two free positions, one on each side of the line 36-37. Secured to the center of the spring 33, by means of a rivet 39, s bi-metal element preferably in the nature of a snap-action disk 40. It is mounted to have a limited degree of movement on the spring, being, however, restrained fromrotation by the provision of a non-circular shoulder upon the rivet 39. Thus the disk may shift slightly upon the spring, but it cannot rotate around its axis.

On the outer edge of the bi-metal element are movable contacts 4|, for engaging stationary contacts 42.. Ends 43 and 44 of the casing slot receiving the handle 32 limit its movement.

"Stops 45 and 46. formed as pins or rods, and

seated in pickets 41-48 molded in the casing are provided for purposes to be described.

Figures 5and 8 show the cool or unwarped condition of the bi-metal element and Figure 7 shows its heated position.

The operation of the device is as follows: When the parts are in the closed circuit position, as shown in Figure 5, and until the handle is moved toward the right, the contacts 4| will be biased with spring pressure against the contacts 42; on movement of the handle, line 363'| will cross the spring 38 so as to snap it to the left of that line as shown in Figure '8 whereupon the contacts, as well as the handle, will be biased towards the open circuit position, as shown in Figure 8. If, thereafter, the handle is moved to the left, the bi-metal element 40 will react on the'stops 4s and as to hold the spring 48 until line 33-31 crosses it, whereupon spring 48 will snap to move the contacts 4| with snap-action to. the stationary contacts and the parts will resume their circuit closing position. j

' In the event of an overload or short circuit, the bi-metal element 40 will warp and snap and assume the position shown in Figure 7, and thus open the circuit. The stops 45-46 do not interfere with such movement or warping of the bimetal. The bimetal element and the spring move a considerable distance, until the bimetal,

so warped, reaches the stops 45 and 46. Thereafter, the spring will expand, and thus move the remain, a characteristic which distinguishes the device of Figures 5 to 8 from the device of Figures 1 to 4 where the parts are not moved to and action only between one position and the other caused to remain in the normal open circuit position in the eventof an overload. Thus, the

breaker of Figures 5 to 8 may be described as of Y the automatic reset type meaning that the handle and other parts are moved automatically to and caused to remain in the normal open circuit position in the event of an overload.

However, if the handle be held by any means in the closed circuit position during an overload release, the parts will notremain in open circuit position but instead will return automatically to the circuit closing position and this de fines the device as a circuit breaker of the automatic reclosing type, meaning that it closes the circuit automatically after an overload opening.

While the axis, of the shaft 34, which mounts the lower endof the spring, is shown as concentric with the axis of rotation of the handle 32, which mounts the upper end of the spring,

' this is not absolutely necessary. The only requirement is that the handlepivot be in such a position that the component of force of the spring 38 tending .to rotate the handle to the V,

open circuit position when the circuit breaker is in the closed circuit position does not exceed the force tending to hold the handle in the closed circuit position and tending to maintain contact pressure. However, concentric pivots are preferred since they provide an identical overload release operation to the parts regardless of whether the handle be held or not held, which characteristic is not true if the pivots for the handle and shaft are eccentric.

Now having described the switches herein indicated, reference may be had to the claims which followfor a determination of the invention.

I claim: 1. A snap switch arranged for manual actuation and for automatic release on overload comprising a stationary contact, a handle, a snap spring, and a bimetal element on said spring and formed with a movable contact for engaging said stationary contact,- with the parts so arranged that handle movement flexes the spring to cause snap movement thereof and the element thereon to and from the stationary contact and on an overload, the bimetal warps to leave the stationary contact, and to flex the spring and snap it to open circuit position, free of the handle it the latter be held.

2. A snap switch arranged for manual actuation and for automatic release on overload comprisinga stationary contact, a handle, a snap spring, and a bimetal element on said spring and formed with a movable contact for engaging said stationary contact, with the parts so arranged that handle movement flexes the spring to cause snap movement thereof and the element thereon to and from the stationary contact, and on an overload, the bimetal warps to leave the stationary contact, and to flex the spring and snap it to open circuit position, free of the handie if the latter be held, and to move the handle to open circuit position if it be not held, or if it be held, when released.

3. A snap switch arranged for manual actuation and for automatic release on overload com.- prislng two stationary contacts, a handle, a snap spring, and a bimetal element on said spring and formed with two movable contacts for engaging and bridging said stationary contacts, with the parts so arranged that handle movement flexes the spring to ause snap movement thereof and the element thereon to and from the stationary contacts, and on an overload, the bimetal warp's' to leave the stationary contacts, and to flex the spring and snap it to open circuit position, free of the handle if the latter be held.

4. A snap switch arranged for manual actuation and for automatic release on overload comprising two stationary contacts, a handle, a snap spring, and a bimetal element on said spring and formed with two movable contacts for engaging and bridging said stationary contacts, with the parts so arranged that handle movement flexes the spring to cause snap'movenient thereof and the element thereon to and from the stationary contacts, and on an overload, the bimetal warps to leave the stationary contacts, and to flex the spring and snap it to open circuit position, free ofthe handle it the latter be held,-

and to move the handle to open circuit position if it be not held, or if it be held, when released.

5. A snap switch arranged for manual actuation and for automatic release on overload comprising a stationary contact, a handle, an overcenter spring, and a bimetal element on said spring and formed with a movable contact for engaging said stationary contact, with the parts so arranged that handle movement, flexes the spring to cause snap movement thereof and the element thereon to and from the stationary contact, and on an overload, the bimetal warps to leave the stationary contact, and to flex the spring overcenter, free of the handle if the latter be held, the handle being in the form of a rocker pivotaily mounted between its ends.

6. A-snap switch arranged for manual actuation and for automatic release on overload com-' prising a stationary contact, a handle, a snap spring, and a bimetal element on said spring and formed with a movable contact for engaging said stationary contact, with the partsso arranged that handle movement flexes the spring to cause snap movement thereof and the element thereon to and from the stationary contact, and on an overload, the bimetal warps to leave the stationary contact, and to flex the spring and snap it to open circuit position, free of the handle if the latter be held, the spring being a flat leaf compression spring with one and connected said stationary contact, with the parts so arranged that handle movement flexes the spring tocause snap movement thereof and the element thereon to and from the stationary contact, and on an overload, the bimetal warps to leave the stationary contact, and to flex the spring and snap it to open circuit position, free of the handle if the latter be held, the element being center mounted and formed to snap and shift its mounting point when it warps.

8. A snap switch arranged for manual actuation and for automatic release on overload comprising a stationary contact, a handle, a flat leaf snap spring having one and connected the handle and the other and mounted in an abut:

ment, and a bimetal element on said spring and formed with a movable contact for engaging said stationary contact, the spring being normally under compression and to one or the other side of the center of handle movement to hold the handle in either of its two positions and to maintain the movable contact in pressure engagement with or separated from the stationary contact, with the parts so arranged that handle movement shifts the spring across said center and also flexes the spring to cause snap movement thereof and the element thereon to and from the stationary contact, and-on an overload, the bimetal warps to leave the stationary contact, and to flex the tothe handle and the other'to a stationary part i of the switch.

7. A snap switch arranged for manual actuation and for automatic release on overload comprising a stationary contact, a handle, a snap spring, and a bimetal element on 'said spring and formed with a movable contact for engaging spring without shifting its ends, but merely its center, and snap it to open circuit position, free of the handle if the latter be held, and thus change the shape of the spring.

9. A snap switch arranged for manual actuation and for automatic release on overload comprising a stationary contact, a handle, a flat leaf snap spring having one end connected to the handle and the other end mounted in an abutment, and a bimetal element on said spring and formed with a movable contact for engaging said stationary contact, the spring being normally under compression andto one or the other sideof the center of handle movement to hold the handle in either of its two positions and to maintain the movable contact in pressure engagement with or separated from the stationary contact, with the parts so arranged that handle movement shifts the spring across said center and also flexes the spring to cause snap movement thereof and the element thereon to and from the stationary contact, and on an overload, the bimetal warps to leave the stationary contact, and to flex the springwithout shiftin its ends, but merely its center, and snap it to open circuit position, free of the handle it the latter be held, and thus change the shape of the spring, and a stop for being engaged by the spring, near the lat-.

prising a stationary contact, a handle, a flat leaf snap spring having one end connected to the handle and the other end mounted in an abutment, and a bimetal element on said spring and formed with a movable contact for engaging said stationary contact, the spring being normally under compression and to one or the other side of the, center of handle movement to hold the handle in either of its two position and to maintain the movable contact in pressure engagement with or separated from the stationary contact, with the parts so arranged that handle movement shifts the spring across said center and also flexes the spring to cause snap movement thereof and the element thereon to and from the stationary contact, and on an overload, the bimetal warps to leave the stationary contact,'and to flex the spring without shifting its ends, but merely its center, and snap it to open circuit position,

free of the handle'if the latter be held, and thus change the shape of the spring, the bimetal element comprising a center mounted bimetal element having thecontact at an outer point.

11. A snap switch arranged for manual actuation and for automatic release on overload comprising a stationary contact, a handle, a fiat leaf snap spring having one end connected to the -handle and the other end mounted in an abutment, and a bimetal element on said spring and formed with a movable contact for engaging said stationary contact, the spring being normally under compression and to one or the other side of the center of handle movement to hold the handle in either of its two positions and to maintain the movable contact in pressure engagement with or separated from the stationary contact, with the parts so arranged that handle movement shifts the spring across said center and also flexes the spring to cause snap movement thereof and the element thereon'to and from the stationary contact, and on an overload, the bimetal warps to leave the stationary contact, and

o flex the spring without shifting its ends, but merely its center, and snap it to open circuit position, free of the handle if the latter be held, and thus change the shape of the spring, and a stop for being engaged by the spring, near the latters center, to restore the latter to its normal shape, when the handle connected end of the spring is moved out of its closed circuit position, whereupon the spring, tho in its normal shape, is in open circuit position, and holds itself, its contact, and the handle in their open circuit po sitions, the bimetal element comprising a center mounted bimetal element having-the contact at an outer point.

12. A snap switch arranged for manual actuation and for automatic release on overload comprising a stationary contact, a handle, a flat leaf snap spring having one end connected to the handle and the other end mounted in an abutment, and a bimetal element on said spring and formed with a movable contact for engaging said stationary contact, the spring being normally under compression and to one or the other side of the center of handle movement to hold the handle in either of its two positions and to maintain the movable contact in pressure engagement with or separated from the stationary contact, with the parts so arranged that handle movement shifts the spring across said center and also .flexes the spring tocause snap movement thereof and the element thereon to and from the stationary contact, and on an overload, the bimetal warps to leave the stationary contact, and to flex the spring without shifting its ends, but merely its center, and snap it to open circuit position, free of the handle if the latter be held,

v stationary contact, the spring and thus change the shape of the spring, and a stop for preventing the element, when unwarped,

from snapping over its own center, but so posi-n tioned as to permit the element,'when heated, to snap over its own center and in so doing to shift the handle, if the latter be not held, to open circuit position.

13. A snap switch arranged for manual actuation and for automatic release on overload comprising a stationary contact, a handle, a flat leaf snap spring having one end connected to the handle and the other end mounted in an abutment, and a bimetal element on said spring and formed with a movable contact for engaging said stationary contact, the spring being normally under compression and to one or the other side of the center of handle movement to hold the handle in either of its two positions and'to maintain the movable contact in pressure engagement with or separated from the stationary contact, with the parts so arranged that handle movement shifts the spring across said center and also flexes the spring to cause snapjmovementthereof and the element thereon to and fromthe stationary contact, and on an overload, the bimetal warps to leavethe stationary contact, and to flex the spring without shifting its ends, but merely its center, and snap it to open circuit position, free of the handle if the latter be held, and thus change the shape ofthe spring, and a 'stop for preventing the element, when unwarped,

but so posi.

from snapping over its own center, tioned as to permit the element, when heated, to snap over its own .center and in so doing to shift the handle, if the latter be not held, to open circuit position, butif the handle be held, the element will automatically return to circuit closing position;

l4. A snap switch arranged for manual actuation and for automatic release on overload comprising a stationary contact, a handle, a flat leaf snap spring having one end connected to the handle and the other end mounted in an abutment, and a bimetal element on said spring and formed with a movable contact for engaging said being normally under compression and to one or the other side of the center of handle movement to hold the ham die in either of its two positions and to maintain the movable contact in pressure engagement with or separated from the stationary contact, with the parts so arranged that handle movement shifts the spring across said center and also flexes the spring to cause snap movement thereof and the element thereon to and from the stationary contact, and on an overload, the bimetal warps to leave'the stationary contact, and to flex the handle, it the-latter be not held, to open circuit position, the handle and the abutment being rotatablymounted on concentric pivots.

ELWOOD T. PLATZ.

its own center, but so positioned

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