US1761117A - Safety switch - Google Patents

Description

June 3, 1930. B. E. Gr-:TcHl-:LL

SAFETY SWITCH Filed March 25, 1929 INVENTOR June 3, 1930., B E GETCHELL 1,761,117

SAFETY SWITCH Filed March 25, 1929 v 5 Sheets-Sheet 2 1.47 Z/ z I June 3, 1930. B. E. GETCHELL SAFETY SWITCH l Filed March 25, 1929 3 Sheets-Sheet 3 INVENTOR Y ,l 'xl Patented June 3, 1930 i UNITED sierrasv PATENT l oFFlcE BENJAMIN E. GETCHELL, OF PLAINVILLE, CONNECTICUT, ASSIGNOR TO THE TUMBUID ELECTRIC MANUFACTURING COMPANY, F PLAINVILLE, CONNECTICUT, A CORPORA- TION'OF CONNECTICUT sanare' swrrcn applicaties. fue@ umn at, ieee.. serial no.

l gie type having an operating handle for Ell' manually causing the usual on and ci movements of the switch under normal circuit conditions. ln this present construction there is also included an automatic means for releasing coacting parts so as to open the circuit with a snap action on predter- Amined overload conditions.

Switches of this type may he used for various purposes particularly tor stai-ting, stopping and automatically protecting small motors against overloaded circuit conditions.

@ne object of my invention is to provide a switch having an operating handle for the manual operation of the switchunder all normal conditions and a normally inactive latching meansor automatically releasing the switch and causing the complete circuit opening movement of the switch under overloaded circuit conditions.

Another object is to provide a switch of the preceding description in which the automatic releasing parts are trip-tree from the operating handle and the switch will be opened with a snap action whether it is operated manually or automaticallyB Another object is to provide a switch having a handle ior manual operation under normal circuit conditions and an automatic means :tor causing the complete circuitl opening movement of the switch under overload conditions even though the operating handie he *forcibly held in the on position.

Anotheroloject is to provide a normally manually operalole switch with an inaccessilole means `lor automatically operating the switch to fully open the circuit on predetermined overload conditions and which will also move the handle to oil position when the switch is so operated and further, will so position the co-related latching' means that the switch will be relatched and ready for continued use as soon as the thermal latching means has cooled.

Another ohject is to provide a switch having automatic thermal latching means hy which means the switch may he accurately calibrated at the factory after all of thecorelated parts are assembled and the parte may then loe inaccessihly enclosed in a suitahle switch hase or housing.

Another oloject is to simplify the construction of switches of this character.

Fig. Il is a front view of a wall switch front plate and showing ,the body of the switch in dotted lines.

Fig. 2 is a vertical sectional view of the hody and showing the side view of the switch proper with the parts in the o or open circuit position.

llig. 3 is a rear view showing the thermostatic elements.

Fig. l is a vertical sectional view showing the switch details in the 0E position.

llig. 5 is a view similar to Fig. 4: lout with the switch parts in the closed circuit or on position.

llig. 6 is a sectional view showing the parts in one of the intermediate positions just after opening the circuit thermostatically and hefore the parts are reset.

TFig.I 7 is a rear view of the switch frame and movable switch member.

llig. 8 is an exploded perspective view of various parts of the switch.

The preferred embodiment of the invention includes an insulating loody or housing. 9 which may have a iront yoke 10 to facilitate mounting in the usual wall box or receptacle. This yoke may he secured hy screws l1 which also secure in place a rear cover plate l2. A iront plate 13 may also he secured in the usual way for instance Qby screws 14.

rlhe switch mechanism proper is mounted in a recess in the housing 9. rll`he switch frame is made up of side plates l5 .which may loe secured 'together by a plate 16 and pins l? and 18, all of which may he riveted or otherwise suitably secured in place.` The :trame may he anchored in the housing by screws 19.

The movable switch contact memher may loe secured to an insulating strip 21- which inv turn is riveted to contact carrier Q2. rlhis carrier preferably is made up of two sheet metal stampings secured together hy pins or rivets' 23, 2l and 25. The ends of.- the pin 23 extend through slots 26 in the side plates of the frame so as to guide one end of the contact carrier and ermit it to oscillate about the axis of the pin 24 at the outer end during certain movements of the switch. The pin 24 is supported in the catch or latch member 27 which is pivoted on the pin 18. Part of the slot 28 guides the pin 24 in an approximately straight line.V

away from the pin 18 and the front end of the slot 28 is vinclined toward the center of the switch. The action of the pin 24 in slot 28 will be described hereinafter.

A bi-metallic thermostatic latch or catch member 29 has one end secured to the frame for instance by riveting to the lugs 30. The other end co-acts with the tip 31 of the pivoted catch 27. A screw 32 passes through theJ member 29 and screws into a seat in the plate 16 so that the latch may be adjusted to engage and disengage the tip 31 of the catch 27 at the proper time.

The operating handle 33 has a metal shank 34 pivoted on the pin 17.V The rear end of this shank has an inclined slot 35 the Wall of which co-acts with the central pin 25 of the switch contact carrier. A spring 36 mounted on the pin 17 coacts with the shank 34 of the handle lever and with the stationary frame so as to tend to bias or move the operating lever to the off or open circuit position. p

The spring 37 connects the pin 23 of the contact carrier with the plate 16 at the rear of the frame so as to tend to draw the contact end of the carrier rearwardly.

The practical form herein shown and described is a double break mechanism with terminals and switch contacts on opposite sides of thecenter line. One of the circuit terminals is secured to the front end of the bracket 40 and the stationary contact is secured to the bracket 41. These two brackets are suitably secured in the housing and connected together by the link 42 at the rear. The bracket 43 provides the other circuit terminal and the bracket 44 supports the other contact member. The brackets 43 and 44 are suitably secured in the housing and connected together at the rear by a high resistance heater stri 45 which lies close to one surface of the bi-metallic thermostatic latch plate 29.

The relatively stationary switch contacts are preferably resiliently mounted so as to yield when engaged by contact bar 20. A spring strip 46 is secured to the rear end of the bracket 41 and has its front end inclined and provided with a contact faceplate 47. A pin 48 extends through the perforation 49 in the strip 46 and into the bracket 41 to limit the movement of the contact member 47 A similar spring strip 50 is secured to the bracket 44 and is provided with a contact plate 51.

When the circuit is open, that is, when the switch is in the ofi' position, the spring 37 holds the main switch contact carrier yieldingly in the position shown in Fig. 4, where the lower end of the arm 22 rests against the abutments 52 on the frame and the pin 24 is in the rear end of the slot 28.

To close the circuit the switch lever or handle 33 is raised to the position of Fig. 5. By the movement of the inner forked end of the lever 34 the switch contact carrier 22 is drawn outwardly toward the front of the switch into the position shown in Fig. 5, the lower end being guided by the pin 23 in the slot 26 and the upper end being guided by the pin 24 in the slot 28. The upper end stops against the shoulder 53 and the contact 20 stops against the"v contact plates 47 and 51.A The contacts yield sufiiciently to allow the pin 25 to slip into the notch 54 in the shank of the operating handle, in which position the spring 37 tends to hold the parts yieldingly.

To open the circuit it is simply necessary to turn the handle 33 down so that as soon as the pin 25 slips out of the notch 54 the spring will snap the contact carrier to the open circuit position aided by the action of the spring 36 upon the finger lever or handle.

If when the switch is closed or on, the circuit is overloaded beyond the predetermined capacity of the switch the thermostatic plate will be warped sufficiently to release the tip 31 of the catch 27, thus permitting the catch to tilt about its pivot 18 and release the pin 24 at the upper end of the carrier arm A22. The carrier arm can then rock about the pin 25 under the tension of the spring 37 so as to open the circuit with a snap action immediately followed by the movement of the handle 33 to the ofi:l position under pressure of the spring 36.

When the tip has been released in this manner the spring 37 will cause the carrier member 22 to tilt and move in such a manner that the pin 24 will move to the upper end of the slot 28 in the catch member 27 thus causing the catch member to move into approximately the position shown in Fig. 6 but, as soon as the spring has snapped the contact carrying end of the carrier to rest upon the abutments 52 of the switch frame, the spring will then draw upon the carrier in such a manner as to cause the pin 24 to move to the inner end of the slot 28 in the catch member 27 and thus force the tip 31 of the catch back into position just clear of the path of the moving end of the thermostatic member 29.

When the thermostatic member has cooled sufficiently, it will have resumed its normal latching position directly in the path of movement of the tip of the catch member 27 It will be especially noted that this construction includes a mechanically novel feaand the slot 28 in the catch member 27'its correlation with the pin 23 and the slots 26 in the frame members 15 and its correlation with the pin 25 and the inclined cam slot 54 in the stem of the operating handle member 33, said carrier is caused to move relatively and bodily up and down, to move in an endwise direction and to rock upon the respective pin members at different times Whlle performing its cycle of movements.

It should be understood that various changes may be made in the construction and mode of operation without departing from the spirit and scope of my invention.

This construction has already proved to be highly successful commercially and it should be understood that the claims are intended to be interpreted broadly.

I claim:

1. A snap switch including a movable switch member having a guide pin, an inclined guide therefor, a catch coacting with one end of said member to hold it and a thermostatic latch for holding said catch, under normal circuit condition.

2. A movable switch member having laterally projecting guide ins, guides for said pins, a pivoted catch or one end of said switch member, a latch for said catch, means for adjusting said latch, and snap mechanism coacting with said switch member to operate and to reset said latch.

3. In a safety switch, a movable switch member having a guide pin, a guide therefor, a pivoted catch for normally supporting one end of said switch member, a thermostatic member for holding the catch under normal circuit conditions, and means for adjusting said thermostatic member.

4. In a switch a switch member mounted to move at both ends, a thermostatically releasable means for engaging one end ofn said switch member under normal circuit conditions, a pivoted handle lever having an inclined slot for engaging said switch member, said slot having a recess serving to engage and hold the switch member in the closed circuit position under normal circuit conditions.

5. In a switch, a frame, a pivotally mounted switch member movable in its entirety in various directions, a pivoted catch for engaging one end of the switch member under normal conditions, a thermostatic member coacting with said catch to hold said switch member in the open and closed positions, under normal circuit conditions, and a spring connected to the switch member tooperate the switch under normal circuit conditions and to force it to reset the catch after it has been released by said thermo! static member.

6. In a switch a frame having a guide, a movable switch member having a uide pin near one end and adapted to sli e on the guide, a pivoted catch having a slot with sliding connection with the other end of said switch member, a thermostatic latch coacting with said catch, a handle lever pivoted to the frame and having an operatingv connection with said switch member, a spring coacting with the handle lever to bias it toward open circuit position and a spring connecting the frame and switch member. to draw the latter toward open circuit position independently of the other sprmg. 7. In a switch, a frame having a guide slot, a movable switch member having a pin near one end guided to slide in said slot, a pivoted catch having a sliding connection with the other end of the switch member, a thermostatic latch coacting with said catch, a handle lever pivoted to the frame and having a sliding and pivotal connection with said switch member, a spring coacting with the handle lever to bias it toward open cir cuit position and another spring connecting the frame and switch member to draw the latter toward open circuit position independently o f the other spring.

8. A switch including a frame, a stationary contact member, a movable contact member adapted to be moved into and out of engagement with said stationary member, a handle for normally operating said movable contact member and thermally actuated means for independently moving said movable contact from engagement with said stationary contact when the switch becomes overloaded, said means including an arm member carrying said movable contact member and normally movable bodily into and out of engagement with said stationary contact member, a catch member and a thermo- ,static member coacting therewith for n ormally holding said arm against pivotal movement, and a spring member for pivota lly movlng said arm away from the stationary contact member upon the ..release of said catch. i

9. A switch including a frame, a stationary contact member, a lever arm ioatingly mounted in said frame, a Contact member fixed to said arm and adapted to engage sald stationary contact member, a spring for normally keeping said arm and contact member disengaged from said stationary contact member, and a handle operatively connected to said arm for moving said arm into and out of engagement with the stationary contact, said handlebeing adapted to exert a leverage action on said arm to operably move said arm. j 10. A switch including a frame, a stationary contact member, an arm mounted in said frame and adapted to move bodily therein and normally held against pivotal movement, a contact member carried by said inovable arm, a device for normally moving said arm and its contact member bodily into and out of engagement with said stationary contact member, means carried by said device for holding said contact members in engagement, and thcrmostatically controlled means for permitting pivotal movement of said arm out of engagement with said stationary contact member.

11. A switch including a frame, a stationary Contact member, an arm mounted in said frame and adapted to be moved bodily therein in a plurality of planes and arcuate positions, a Contact member fixed to one end of said arm and adapted to engage said stationary contact member, a catch member pivotally mounted in the frame and connected to one end of said arm and adapted to prevent pivotal movement of said arm, a latch member normally in engagement with said catch to prevent the pivoting of the latter, thermostatically controlled means for releasing said catch from said latch, and means for pivotally moving said arm when the catch is released to disengage said contact members.

12. A switch comprising a frame, a stationaiy contact member mounted in said frame, an arm mounted in said frame and adapted to be moved bodily therein, a contact member carried by sai arm at one end, a handle, a lever operated` by said handle,

said lever engaging/,i said arm substantiallyv midway its length through a slot and stud connection and adapted to bodily move said arm and contact member into and out of engagement with said stationary member, said frame formed with a slot to guide the movement of said arm, a catch member pivotally mounted on said frame and engaging said arm at its other end, said catch being adapted to permit bodily movement but to prevent pivotal movement of said arm under normal circuit conditions, a latch normally adapted to engage said catch to prevent pivotal movement of said catch undei normal circuit conditions, a heater mounted adjacent said latch and adapted to heat and warp said latch away from the catch when the switch is overloaded, and a spring acting on the contact carrying end of said arm for pivoting said arm around its center stud upon the release of said catch to disengage the contact members.

13. In a snap switch a pivoted operating lever, movable switch contact member having a pivot pin slidably and pivotally connected with said lever and means for slidably guiding the opposite ends of. said contact member, a pivoted latch providing support for one end of said contact member and a thermostatic catch coacting with said latch.

14. In a snap switch a pivoted operating lever, a. floating contact member slidably and pivotally connected with said lever and thermostatically releasable means for assisting in holding the contact member in closed circuit position.

15. In a snap switch a pivoted operating lever having an inclined slot with a recess at one end, a movable contact member having a pivot pin guided in said slot and adapted to rest in said. recess when in closed said contact member.

17. A snap switch including a pivoted operating lever, a floating contact member slidably and pivotally connected with said lever spring supported contacts adapted to be engaged by said contact member and thermostatically releasable means for assisting in holding the contact member in closed circuit position.

A snap switch including a pivoted operating lever, a spring tending to move the operating lever to the open circuit position, a floating contact member operatively connected with said lever, spring supported contacts adapted to be engaged by said contact member, a spring separate from the first spring tending to move the contact member to open circuitposition and therniostaticallv releasable means coacting with said contadt member.

19. A snap switch including a pivoted operating lever having an inclined slot with a recess at one end, a contact member having a pivot pin guided in said slot and adapted to rest in said recess when in closed circuit position, spring supported contacts adapted to be engaged by said contact member, thermonstatically releasable latching means coacting with said contact member and a spring coacting with said contact member to open the circuit.

20. snap switch including a pivoted operating lever, a switch contact member having a pivot pin slidably and pivotally connected with said lever and means for slidably guiding the opposite ends of said contact member, sprin supported contacts adaptedto be engaged y said contact member, a pivoted catch providing sup )ort for one end of said contact member an a thermostatic latch coacting with said catch.

BENJAMIN E. GETCHELL.

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