US2180025A - Heat-responsive switch - Google Patents

Description

N0v.14,1939. -V. WEBER 2.180.025

HEAT -RESPONS IVE SWITCH Filed June 24, 1956 Z0 /m/E/vroe, V/cro@ wfee,

Patented Nov. 14, -1939 y i 2,180,025

lUNITI-:D STATES PATENT OFFICE' HEAT-nnsroNsIvn SWITCH victor. weber, st. Louis, Me., assigner to The Emerson Electric Mfg. Co., St. Louis, Mo., a l corporation of Missouri Application :une 24, 193s. serial No. sessi.

s cima. (ci. zoo-124) The present invention relatesgenerally to cir- .free thermally-responsive circuit breaker or cuit breakers or automatic switches, and more switch constructed in line with the present inparticularly to atrip-free thermally-responsive vention, thatincludes a base I I which is of a noncircuit breaker for use in heat-cooperative` relaconducting material. Holes I2 are disposed 5 tion with an energy-translating device. through the base for ythe purpose of receiving 5 The -invention contemplates the provision of a bolts, or the like, (not shown) to secure the cirtrip-iree thermally-responsive circuit breaker of4 cuit breaker to a support. A iianged support simple construction, which is adapted to be member Il is mounted on the base Il by means mounted within the shell of a motor, or other of rivets I4, or the like, and includes an atl energy-translating devices, and includes mechtaching portion I5, a vertical portion I6, and'a I10 anism releasable to break the switch contacts achorizontally disposed iiange I 1. 'I'he vertical portuated either from ambient heat generated in the tion I8 terminates at one en d in an extension I8 energy-translating device itself, or from heat which hasan openingIS therethrough. A cygenerated by anexcessive current passing through lindrical hub 20 is iixed to the extension I8 by l aheater element included as part of the circuit means of peening over, as at 2|, one end there- 15 breaker assemblage. of. Qn a -reduced portion 22 of the hub 20 f An object of the present invention is to prothere is disposed a ratchet wheel 23 having teeth vide a thermally-responsive trip-free circuit 2l. Between the wheel 23 and the reduced porbreaker. l I tion 22 is a layer of solder 25 which, under nor- Another object is to provide a trip-free thermal temperatures, is adapted to fix the wheel 23 20 many-responsive circuit breaker which is adaptrelative to the said hub. A spring blade 26 is ed to function-at a predetermined temperature fixed to the plate Il by means of a rivet 21, or to interrupt an electrical circuit. the like, and is'adapted to lie beneath the iiange Another object is to provide a trip-free circuit I1 of. the support member I3. A switch blade,

breaker adapted to break contact either from an generally indicated 28, is secured to the underside 25 excessive ambient heat, or .from an excessive of the flange I1 by means oi a rivet 30, or the heat generated in a heater element intimately like, and includes an attaching portion 3|, a right associated with the circuit breaker. angularly disposed intermediate portion 32, a

Another object is to provide a trip-free clrhorizontally disposed portion J3 which is adapt- 30 cuit breaker adapted to break contact uon an Y ed t0 lie in @Opere-ting Ieletion iiD the Spring 30 excessive heat generated by a heater disposed blade 2B, and-a toe portion 34 which is adapted in intimate association with the circuit breakers t0 selectively el'lgage e tooth 24 0f the ratchet Another object is to provide circuit breaker Wheel 23- l Beth the Spring blade 25 and the automatically operable at a predetermined tem; switch blade 28 are of resilient material which perature to break a circuit which includes manubiases them'tO Open position (Fig. 3), and they 35 any operable elimine-reset menu make current transferring contact at 29 only when Other objects and advantag will appear from S0 held by the ratchet Wheel (Fig. 2). The the following description, taken in conjunction Spring blade 25 may be Called e terminal memwith the accompanying drawing, in which ber and the switchblade a contact member for Fig. 1 is aplan view of a preferred embodiment more Vdeiinite electrical designation. OI course, o

of a circuit breaker constructed in the light of both blades are contacts. the present invention including in the assemblage A11 Operating member, generally indicated 35,

a heater element. has pivotal connection with the iiange 'I1 by Fig. 2' is a side elevation thereof showing the means of a toe portion 31 ofthe member coelements in contacting or closed relation. operatively engaging a slot 36 in the flange. 'I'he 45 Y Fig. 3 is a side .elevation thereof showing the member 35 inClUdeS eli intermediate portion 38, a

elements in open relation. handle Il, a ilrst heel 40, a guide projection 4I r Fig. 4 is a'section on the line -J o! Fig. 1. and a secondheel 42. The handle 39 is adapted" Fig. 5 is a section on the line 5 5 oi Fig. 1. to move substantially vertically in a slot 45 ini f 5o Fig. 6 is a section on the une -s or Fig. 1. the flange I1. The guide proiection 4I extends 5o'` Fig. I is a plan view of a portion of a circuit through a slot I3 in the base II and cooperates breaker and heater element assemblage, showing with the handle and its'"associ'ated slot to guideV a modiiied relationship therebetween. the member 35 in its substantially vertical move- Referring more particularly to the drawing by -'ment. The switch blade 28 has a slot 44 there., reference numerals, Il indicates generally a tripthrough which is adapted to encircle the heel I 55 and the projection 4| to allow relatively free movement between the switch blade and the operating member. The spring blade 26 has a short slot 46 in the free end thereof which is adapted to straddle the projection 4I.

A heater element, generally indicated 41, is connected to the vertical portion I6 of the support by a rivet 48, or the like, and to a terminal post 50, thereby being in series with the switch and the circuit. The heater element includes a loop 5l which extends into the interior of the cylindrical hub 20 in heat-transferring relation thereto. Of course, this heater element may be omitted, if desired, for a particular use oi the circuit breaker. One lead 53 is connected to the terminal 50, and a second lead 54 is connected to the rivet 21, which thereby serves as the other terminal, the said leads being adapted to connect the circuit breaker in the circuit to be protected.

In Fig. 7 there is shown a modied arrangement of a circuit breaker constructed in accordance with the present invention and a heater element. In this set-up a heater element generally indicated 60 having loop portion 6| and irregularly shaped portions 62 is connected to terminals 63 and 64, respectively, which are disposed in spaced relation in the insulating base II.- Leads 65 and 86 serve to connect the heater in its enerrent that in this assemblage the switch is in to 'peratures by the solder 25.

control one circuit while the heater element is in a different energizing circuit.

The operation of the device The circuit breaker of the present invention is particularly adapted for mounting within the casing of a motor, although it is obvious that it may be used with other electrical devices and for other electrical purposes. In its use with a motor, the circuit breaker is mounted in close proximity to the neld windings so as to receive heat generated therein and radiated therefrom. The circuit breaker is connected in series in the line, or in the starting or running windings of the motor, dependent upon the type employed in an instant installation and the circuit desired protected. When thus connected and in closed position, current passes in lead 54 and succes-f sively traverses the springv blade 26, the contact point 25, the switch blade 28, the support I3, the heater coil 41, and out lead 3l. Inasmuch as the easiest path is through the support I3, very little current actually passes through the cylindrical hub 20 and the ratchet wheel 22. These latter elements may, of course. be insulated from the support.

As has been indicated above, the ratchet wheel 23 is adapted t o be held iixed relative to its supporting cylindrical hub 20 under normal tem- When so fixed, it serves as a latch for holding the switch blade 28 in the position shown in Fig. 2. 'I'he switch blade is brought to this position and into this relation with the ratchet wheel from an open position in Fig. 3 by manually, or otherwise, pressing the handle 39 downwardly, which, in this movement, carries with it the switch blade 23 and the spring blade 2G, inasmuch as the heel 42 bears against the toe 34 of the switch blade and theheel 43 Aheat within the casingl will, ata predetermined temperature, so soften the solder 25 as to allow the. ratchet wheel to rotate upon its cylindrical support, thereby releasing the switch blade 2l to permit it, through its inherent resiliency, to move upwardly with a substantial snap-action to assume the position disclosed in Fig. 3. This upward movement is stopped by .theconnecting portion 38 of the member.35. Simultaneously with the movement upwardly of the switch blade, the spring blade 26 moves from the position shown in Fig. 2 to that shown in Fig. 3, being stopped nally by the heel 40. Thus, Athe blades are separated and contact is broken in the switch which, of course, results in interrupting the supply of current to the motor, thereby stopping it. Further, the switch is adapted to open in likemanner from heat generated by the heater element 41 from an excessive current passing therethrough, as would be the case should the motor become blocked and the back E. M. Il'.V

reduced.

It is apparent from Fig. 7 that the circuit breaker may bel connected in one circuit and the heater element in another. 'I'hat is, the circuit breaker may be in the main line while the heater element is in the main or starting winding circuit.

Thus, a trip-free thermally-responsible circuit breaker has been provided which, when used with a motor, or the like, is adapted to open at a predetermined temperature upon a gradual rise in heat'in the motor, or upon sudden rise in heat generated from an abnormal current through the heating element. Of course, it is adapted to function upon a combination of these two factors, there being only the one release "of illustration and example and not by way oi' limitation, the invention being limited only by the following claims.

What is claimed is:

1. A circuit breaker comprising a base of no conductive material, a support mountedon the base, a terminal blade nxed at one end to' the base out of engagement with the support, a resilient contact blade xed at one end to the support and adapted tobe moved intocontct with said terminal blade, a trip-tree operating handle pivotally connected to the support and adapted to move said contact blade, and a ratchet wheel mounted on' said support and normally maintained in nxed relation thereto by solder, said ratchet wheel being adapted to be engaged by said contact blade when said blades are in operative contact, said ratchet wheel being adapted to release saidcontact blade to permit it to withdraw from the terminal blade at a predetermined temperature.

2. A circuit breaker comprising a base of nonconductive material, a. support, a terminal blade, a contact blade, a solder-ilxed ratchet wheel, and a trip-free operating handle, said terminal blade and support being mounted on said base in spaced relation, said contact blade, ratchet wheel, and operating handle being mounted on said support, said contact blade in current-passing disposition of said elements being restrained by said ratchet wheel in a position in contact with said terminal blade, said ratchet wheelbeing adapted to rotate at a predetermined above normal temperature to release the contact blade to permit it to move away from said terminal blade.

3. A circuit breaker comprising a base, a supthe support, said members being biased to nonengaging positions, thermally-responsive locking means for holding said members in positions for engaging relation adapted to release the same at a predetermined temperature, and a. trip-free operating member for resetting said members to engaging position after a release, said operating member `including means adapted to pass through the slot of the contact member to engage the terminal member, and means adapted to engage the contact member after the iirst means has passed through and cleared the same, whereby the terminal member will be positively main- 1 VICTOR WEBER.

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