US2145811A - Overload switch - Google Patents

Description

Jan. 31, 19391 f F. 1. EAST 2,145,811

OVERLOAD SWITCH Filed Jan. 4, 1935 2 Sheets-Sheet l /5 /0 IT INVENTOR w N E 58 F/F/I/V/(J. 5,4,2; 0565/7550, 5 2 H 37 Karma/3W5 #5; XECl/T/P/X ATTORNEYS Jan. 31, 1939. J. BAST 2,145,811

OVERLOAD SWITCH Patented Jan. 31, 1939 UNITED STATES PATENT OFFICE OVERLOAD SWITCH Frank J. Bast, deceased, late of Queens Village, N. Y., by Katherine Bast, executrix, Queens Village, N. Y., assignor to Charles J. Tagliabue Mfg. 00., Brooklyn, N. Y., a corporation of New York Application January 4, 1935, Serial No. 387

20 Claims.

. -nism can be employed in all types of circuits and apparatus where a device sensitive to a current in excess of a predetermined maximum is desired, it will be described, for the sake of greater clarity, in connection with the control mechanism of an automatic refrigerator.

After an electrically driven refrigerator has been defrosted, the switch is closed, as is well understood in the art, in order to set the motor into operation, to cause the compressor to compress the refrigerant and thus start the refrigeration cycle. At this time the danger arises that the temperature of the refrigerant has risen to so high a value that an excessive load is placed upon the compressor and thus upon the driving motor. Under such conditions there is a likelihood of too high a current traversing the coils of the motor, with the resulting danger of burning out of the motor windings.

It is known to provide refrigerator controllers and similar apparatus with an overload device which operates automatically to open the motor circuit when the current becomes excessive, such device being operable also manually. In such known devices, however, the housewife or other attendant can close the overload switch as soon as it has opened, and thus the impatient housewife, or any one ignorant of the causes bringing about the automatic opening of the switch, is free to close the switch immediately and repeat such closing after every automatic opening, so thatin effect a continuous, dangerously high current may be charged to the motor and the windings of the latter thereby subjected to overheating and even permanent injury.

It is the primary object of the present inven tion to provide an overload device, and particularly an overload switch, for automatic refrigerators, which is absolutely fool-proof, that is, while the overload conditions exist, the contacts cannot be closed manually and hence the supply of current to the motor is interrupted until danger to the motor windings is eliminated.

It is also an object of the invention to provide an overload switch of the type above indicated which operates by a snap action and is free from arcing at the contacts.

It is a further object of the invention to provide an automatic overload device which can be operated also manually to open and close the circuit, and in which the manual switch lever will automatically'he thrown to the oif" position when the device is tripped and the contacts opened upon overheating; and to provide an overload mechanism in which movement of the switch lever to the on position will not effect closing of the contacts so long as the overload condition remains, and in which at such time the lever will not deceptively remain in the on position, but will, as soon as it is released, return to the off position.

It is also an object of the invention to provide a device which is extremely compact, is thoroughly reliable in operation and is inexpensive to manufacture on a large scale.

In the preferred form of the present invention, the mechanism can be thrown on and off manually, so that it may be made to operate as a defrosting switch or as a main control switch, but when the manually engageable switch is thrown to an off position by the overload release, it cannot be made to remain in the on position so long as the overload condition persists as evidenced, for example, by the heated condition of a heating coil or equivalent device, the switch returning automatically to the off position, if it has been manually shifted to the "on position, and the contacts remaining open even when the manual switch lever is held in the on position. However, as soon as the cause of overload has been removed, or when the heating coil temperature has fallen to a safe level, manual operation of the switch will cause closing of the circuit and resumption of the temperature control by the controller.

The electric terminals controlled by the overload switch may be and preferably are arranged in series with the terminals controlled by the temperature controller with which the refrigerator is equipped. The temperature controller and overload release operate independently of each other, but it will be evident that the overload switch canbe efiective to close the circuit to the motor only when the terminals associated with the temperature controller are likewise closed.

The invention will be further described with the aid of the accompanying drawings which illustrate by way of example a preferred embodiment of the invention in association with a refrigerator controller. In said drawings,

Fig. 1 is a central section, with certain parts in elevation, of a refrigerator control box within which my improved overload mechanism is incorporated;

Fig. 2 is an end section along the line 2--2 of Fig. 1;

Fig. 3 shows a top plan view of the control box;

Fig. 4 is a bottom plan view of the structure shown in Fig. 1;

Fig. 5 illustrates in section certain parts of the overload switch constructed in accordance with the invention, the parts being shown in the inoperative or open switch position;

Fig. 6 is a section taken along the line 6--6 of Fig. 5, looking toward the right;

Fig. 7 is a view in vertical elevation showing in full lines the position of the parts upon automatic opening of the overload switch by the action of an excessive current, the closed position of the switch lever' being indicated in dotted lines;

Fig. 8 shows the position of the parts preparatory to manual throwing of the switch into the circuit closing position, the high temperature due to the previous excessive current having fallen to a safe value;

F lFig. 9 is a top plan view of the parts shown in Referring to Fig. 1, the controller box comprises a casing composed of two parts, In and I I, and made preferably of a molding composition or other insulating material, the two parts being attached to a rigid metallic frame I2 by screws I3, I4, I4','

with a thermostatic bulb I8 which is adapted to be placed in proximity to the expansion coil or other part of the refrigerator in the manner well understood in the art. The bellows I6 engages one end of a stem I 9 whose other end carries a nut I9 which bears against an abutment plate 20 which is urged downwardly by a spring 2| whose other end bears against a plate 22. The latter receives the non-threaded reduced end of an adjusting screw 23 which is received within an internally threaded bushing 24 fixed to a manually operable knob 25. The frame I2 extends along the upper wall of the casing I I, the bushing 24 passing through an aperture in the frame and being provided with an enlarged head 26 which bears against the interior surface of such frame so that upon rotation of the knob 25 the screw 23 is caused to move axially and thereby increase or decrease the resistance of the spring 2| to the expansion of the bellows I6.

The stem I9 is provided with lugs or collars 21, 28 which are adapted to engage the longer member 29 of a toggle device 29, 30, the shorter member 30 being extended into a pair of resilient arms 3| which carry an insulated jumper 32 arranged to cooperate with the terminals 33, 34 (Figs. 1 and 5) the arms 3| straddling the toggle member 29. The member 29 has two upwardly inclined ears 29a at its sides and a downwardly inclined central tongue 295, between which the member 30 engages in abutting knife-edge relation, the opposite ends of such members engaging the resilient vertical arms of a bracket 35 likewise along knife edges. The bracket 35 is fixed to the frame I2 in any suitable fashion, as by means of a sleeve nut 36 which is threaded into the opening in the frame through which the stem I9 loosely passes. The tongue 29b extends into a suitably dimensioned opening in the left arm of the bracket 35 to limit the movement of the toggle members in both directions.

The mechanism just described operates normally to maintain a predetermined range of temperature within the refrigerator in accordance with the setting of the knob 25. This mechanism forms no part of the present invention and may be of any suitable form and construction, the mechanism illustrated being similar to that described in greater detail in my United States Patent No. 1,952,050, dated March 27', 1934.

The switch mechanism forming part of the present invention will now be described. Upon the inclined side portion 31 of the frame I2 is mounted a toggle mechanism which is similar in construction to the toggle mechanism 30, 3|, 35 and includes a U-shaped supporting member 38 which is clamped by a sleeve nut 39 to the inclined frame portion 31. The toggle mechanism comprises also a longer member 40 and a shorter flexible member 4| which meets the member 49 along a knife edge and biases the mechanism to switch opening position. Beyond the knife edge, the member 4| is extended in the form of two spaced flexible metallic arms 4| which straddle the member 40, the free ends of such arms being clamped between insulating plates 42, 43 which carry a jumper or contact member 44 adapted to bridge the contacts 33 and 45. The contact 33, it will be noted, is common to the normal switch mechanism 30, 3| and the overload switch mechanism 40, 4 I.

The ends of the toggle members 40, 4| are supported in knife bearings in the sides of the U- member 38. The member 40 has an integral extension or tongue 46 which is received within an opening in the upper arm or side of the U- shaped supporting member 38 and extends beyond such .arm and is perforated to receive one end of the spring 41 whose other end is attached to a member 48 molded to or otherwise rigidly connected with a hand switch lever or operating member 49. The member 48 is of bifurcated. inverted V-form and the ends 48' thereof are journalled within apertures 50 in upward extensions of a yoke 5| whose side arms straddle the frame I2. The yoke 5| is journalled by means of pins 52 upon a U-shaped bracket 53 rigidly mounted upon the inclined frame portion 31. Upon the sideshown in Fig. l, the yoke 5| is provided with a laterally extending arm 54 whose free end carries a pin 55 upon which is loosely journalled a latch arm 56 which may be made of fibre or other suitable material and carries at its lower arm a metallic spring pawl 51. The latter is arranged to engage a ratchet wheel 58 soldered to a shaft 59 rigidly secured to a bracket 6|) held in position upon the frame In by the screw I4 and by a filler piece GI (see Fig. 5), which may be made of a molding composition and serves to hold the anchored, rectangular-shaped end of the bracket 60 within a rectangular recess in the housing Ill. The arm 54 of the yoke 5| is provided with an inwardly extending pin or lug 62 which engages within a suitable recess in the bracket 53 and serves to limit the oscillation of the yoke as will be explained more fully hereinbelow.

A pair of terminals 63, 83' projects from the under side of the casing I9 and is adapted to be connected in series with the circuit of the motor of the compressor of the refrigerating system and with the source of current. The terminal 63 is connected directly to the contact 34. The terminal 63, on the other hand, is connected to a high resistance wire 64 which has a coil portion surrounding but spaced from the shaft 59, the other end of the wire 64 being connected with the contact 45. The current thus runs through the switch mechanism in the following direction, assuming that both the temperature control switch contacts 32, 33, and 34 and the overload switch contacts 44, 33, and 45 are closed: from the terminal 63' to the contact 34, across connecting jumper 32 to the contact 33, from the latter across the jumper 44 to the contact 45, through the high resistance wire 64 to the terminal 63.

The operation of the improved overload switch is as follows: In the normal course of operation the temperature control switch and the overload switch are both closed as shown in Fig. 1. In this condition of the parts, the finger piece 49 is in the on position as indicated in Fig. 3, while the latch member 56 is held against downward movement by engagement with the ratchet wheel 58. In this position of the parts, the latch member or pawl 56 is in its upper position and the yoke has been swung in a counter-clockwise direction until the pin 62 is in the upper portion of the slot at the side of bracket 53. The journal ends 48 of the operating member 48, 49 bear against the right hand walls of the apertures 50; while the spring 41 is under a slight tension and is in the overthrown position with reference to the pivots 48; the tongue 46 having been shifted to switch closing position. The bias to contact opening position of the toggle mechanism is accordingly ineffective to swing the member 49 to contact opening condition, the mechanism being held in the switch closing position by the spring 41. The pivots 48' press upon the yoke but movement of the latter in a clockwise direction is prevented by the engagement of the latch member 56, 51 with the ratchet wheel 58. In this position of the parts, therefore, the pivots 48' of the operating member 49 are fixed due to the resistance of the latch or pawl member 58, and upon operation of the member 49 the toggle mechanism will be actuated through the tongue 46 to snap the contact member into open or closed position. When the operating member 49 is thrown to the on position shown in Fig. 1, it will be held resiliently in such position by the spring 41 which acts along a line to the left of the pivots 48'. When the member 49 has been shifted to the off position the spring 41 is not under tension and the member 49 can be given a limited movement without affecting the toggle mechanism. It will be noted that in the Fig. 1 position the operating member 49 through its pivots 48' exerts pressure in a clockwise direction upon the yoke 5| and tends to urge the latch device 56 downwardly.

Upon the occurrence of an excessive current, such as would overload the motor and tend to injure the same, the body of solder connecting the ratchet wheel 58 with the shaft 59 becomes fused, so that the wheel is free to rotate upon the shaft. Thereupon the latch 56, 51 moves downward under the action of the tension in spring 41 which acts to pull the operating member or lever 49 downwardly. The yoke 5| is thereupon swung clockwise about its pivot 52, and the tension in spring 41 is relieved. The toggle mechanism, being biased to open position and being no longer locked in switch-closing position by the overthrow spring 41, snaps to switch-opening position and at the same time the member 49 is swung to the open circuit indicating position by the tongue 4" While the overload condition continues, that is, while the solder on the shaft 59 remains molten, the latch mechanism 56, 51 cannot be locked by the ratchet wheel 58 and consequently movement of the operating member 49 toward the left or on position shown in Fig. l merely operates to move the yoke 5| in a clockwise direction, the pivots 48' being moved so far to the right that the overthrow condition of the spring 41 cannot be reached, so that the toggle mechanism cannot be swung to circuit closing position. In this condition of the mechanism the operating member 49 will not remain in the on position if it is moved to such position, but upon release thereof will be swung to the off position indicated in Fig. '7 by the spring 41 and also, if the mechanism is suitably designed, by the tension in the toggle mechanism. The member 49 cannot therefore remain in a deceptive on position while the mechanism is under the influence of an overload condition.

As the contact member or switch 44 is swung to the open condition upon excessive rise of current in the controlled circuit, the clockwise movement of the yoke 5| is limited by the lower wall of the slot in the bracket 53 into which the pin 62 projects. This pin thus limits the clockwise and counter-clockwise movements of the yoke 5|.

From the above it will be clear that the contact member 44 cannot be thrown into circuitclosing position while the overload responsive device 56, 51, 58 is still subject to the effects of the overload condition. Assuming now that the solder on the shaft 59 has congealed sufficiently to hold the ratchet wheel 58 rigidly upon the shaft, at which time the windings of the motor have cooled to a point where they are no longer in danger of injury, the mechanism can now be re-set to close the circuit to the motor or other controlled device. In the embodiment of the invention illustrated, it will be found that, as indicated in Fig. 7, the operating member 49 has assumed an intermediate position in which the pawl 51 engages the ratchet wheel 58 at approximately its central tooth. In such position of the parts it will frequently be found that movement of the member 49 to the extreme left position will not operate to throw the snap mechanism to circuit closing position by reason of the fact that the pivots 48 have not been shifted sufiiciently to the left to enable the overthrow spring 41 to .move the toggle plates 40, 4| to switch closing position. In such case the member 49 must first be shifted to its extreme righthand position, as shown in Fig. 8, such shifting being accompanied by a leftward displacement of the pivots 48; in other words, the yoke 5| is rotated slightly counter-clockwise. At the same time, the pawl 51 engages the upper portion of the ratchet 58, as will be readily understood from a comparison of Figs. '7 and 8. If the operating member is now swung into its left-hand position, the overthrow spring 4'! will operate to pull the toggle mechanism beyond its neutral plane and cause snapping of the contact or switch 44 to closed position. If the switch 32 is at this moment in the closed condition, the circuit to the motor or other device will be closed.

From the above it will be seen that there is provided a fool-proof switch mechanism which automatically opens a circuit when an overload condition arises and which cannot be closed while the effects of the overload condition persist. Moreover, the mechanism is so designed and constructed that the operating member cannot assume a deceptive position, but on the contrary,

the condition of the overload switch can always be detected from the position of such operating member.

It will be understood that while there is specifically disclosed a thermo-responsive device, other types of overload responsive devices can be employed; and likewise other types of snap mechanisms.

It is claimed:

1. An electric switch mechanism comprising a casing, contact members in said casing, one of said contact members being movable to on and off position, an operating member, means connecting said movable contact member with said operating member whereby said movable contact member is caused to move to on and off positions by the operating member during normal operation of said switch, an overload responsive device associated with said connecting means and acting'automatically to cause opening of the movable contact member and to render said connecting means inoperative, upon movement of the operating member, to return the said contact member to closed position during overload conditions, said device including a latch member, mechanism responsive to an excessive current for releasing said latch member, and an element between the latch member, said operating member being pivoted on said element, the latter being the operating memher and normally fixed in position in the latched condition of the latching member to render the operating member efiective on the connecting means, and becoming movable in the released condition of the latching member to render the operating member incapable of acting on the connecting means to close the contact while overload conditions exist 2. An overload switch mechanism comprising a pair of contacts, a toggle mechanism controlling the opening and closing of said contacts and including two permanently fixed supporting members, two toggle elements pivoted at opposite ends upon said supporting members, and spring means urging the other ends of said elements toward each other, a manual member separate from said toggle mechanism and operable to open and close said contacts by way of said toggle mechanism, said toggle mechanism being biased to the open condition, and mechanism acting in response to an excessive current to break the operative connection between the manual member and the toggle mechanism and thereby cause opening of the contacts and render said manual member ineffective on said toggle mechanism to close the contacts While the overload condition persists.

3. An electric switch mechanism comprising a casing contact members in said casing, one of said members being movable to on and off position, a toggle device comprising two arms fixed within said casing and two abutting toggle elements bearing against said arms, one of said elements being connected with said movable contact member and operable to cause rapid opening and closing of said member, an operating member for said toggle device, a spring connecting said operating member with one of the elements of said toggle device, and mechanism responsive to overload conditions associated with said operating member and acting to render the connection between said operating member and the toggle device ineifective to cause closing of the movable contact member upon actuation of the operating member during overload conditions.

4. An electric switch mechanism comprising a casing, contact members in said casing, one of said members being movable to on and oil position, a toggle device comprising two arms fixed within said casing and two abutting toggle elements bearing against said arms, and biased to the switch opening position, one of said elements being connected with said movable contact member and operable to cause rapid opening and closing of said member, an operating member for said toggle device, a spring connecting said oper-- ating member with one of the elements of said toggle device, and mechanism responsive to overload conditions associated with said operating member and acting to render the connection between said operating member and the toggle device ineifective to cause closing of the movable contact member upon actuation of the operating member during overload conditions.

5. An electric switch mechanism comprising contact members, one of said members being movable to on and off position, a toggle device connected with said movable contact member and operable to cause rapid opening and closing of said member, a second toggle device connected with the first toggle device for operating the latter and including a manually operable member, and mechanism responsive to overload conditions associated with said operating member and acting to render the first toggle device ineffective to cause closing of the movable contact member upon actuation of said operating member during overload conditions.

, 6. A switch mechanism as set forth in claim 5, wherein the second toggle device includes a spring connected to the first toggle device.

'7. A switch mechanism as set forth in claim 5, wherein the first toggle device comprises two members held in pivotal abutting relation, and wherein the second toggle device includes a spring connected at one end to the operating member and at its other end to one of the members of the first toggle mechanism.

8. An electric switch mechanism comprising a movable contact member, an operating member for said contact member, means connecting said operating member with said movable contact member, said operating member being adapted to move said contact member to on and oil positions during normal operation of said switch mechanism, said connecting means including a lever fixedly pivoted intermediate its ends, said operating member being pivoted on said lever to one side of the pivot of said lever, a spring connected to the operating member and to the contact member and adapted to be thrown to one or the other side of the pivot of the operating 9. An electric switch mechanism comprising contact members, one of said members being mo-vable to on and off position, a toggle device connected to said movable contact member for operating the same and including abutting elements and resilient means acting on said elements, an operating member, an overthrow spring connection between said operating member and the toggle mechanism, said operating member being normally efiective to cause opening and closing of the movable contact member, and mechanism responsive to an excessive current through the circuit controlled by said contact members for rendering ineffective the connection between the operating member and said toggle mechanism.

10. An electric switch mechanism comprising contact members, one of said members being movable to on and off position, a toggle device connected to said movable contact member for operating the same, an operating member connected to said toggle mechanism and normally effective to cause opening and closing of the movable contact member, and mechanism responsive to an excessive current through the circuit controlled by said contact members for rendering ineffective the connection between the operating member and said toggle mechanism, said overload mechanism comprising a shaft, a ratchet wheel on the shaft, a longitudinally movable pawl device engageable with said ratchet wheel, and heat-sensitive means controlling the engagement of the wheel by said pawl, the connection between the operating member and the toggle device including a pivoted lever normally held against rotation by the pawl device, said lever and operating member forming parts of a second toggle device.

11. An electric switch mechanism comprising a casing, contact members in said casing, one of said members being movable to on and off position, a toggle mechanism connected to said movable contact member for operating the same and comprising a pair of resilient arms fixed to the casing and two abutting plates bearing against said arms, an operating member connected to said toggle mechanism and normally effective to cause opening and closing of the movable contact member, and mechanism responsive to an excessive current through the circuit controlled by said contact members for rendering ineffective the connection between the operating member and said toggle mechanism, said overload mechanism comprising a shaft, a ratchet wheel on the shaft, a longitudinally movable pawl engageable with said ratchet wheel and associated with the toggle device and operating member, said pawl determining by its position whether or not the toggle mechanism can be snapped to circuit closing position by said operating member, and heatsensitive means controlling the engagement of the wheel by said pawl.

12. An electric switch mechanism for refrigerators comprising a casing, means responsive to a physical condition at a selected point for periodically opening and closing the circuit of the refrigerator motor to maintain the temperature in the refrigerator within selected limits, contact members in said casing in series with the motor circuit, one of said contact members being movable to on and off position, an operating member normally operable to shift the movable contact member to on and off position, mechanism responsive to an overload condition in the motor circuit and effective then to cause opening of the contact member, means controlled by said overload responsive mechanism and acting to render said operating member ineffective to shift. the movable contact member to on position while the effects of the overload condition continue, said operating member being constructed and arranged to be freely movable to positions corresponding to the on and off positions of the movable contact member while the effects of the overload condition persist, and means for returning the operating member to a position corresponding to the off position of the movable contact member after such operating member has been moved to the on position while the effects of an overload condition continue.

13. An overload switch comprising, in combination, a contact member, a snap device for moving said contact member into open and closed positions, a reciprocable operating member connected with said snap mechanism for operating the same to open and close the contact member, a movable support for said operating member, mechanism responsive to an excessive current to cause shifting of said support and thus interrupt the operative connection between the operating member and the contact member while the effects of an excessive current persist, said snap mechanism moving to contact open position upon shifting of said support and said operating member being moved to corresponding position, and means for returning said operating member to open circuit indicating position after it has been moved to circuit closing position while the effects of an overload condition persist.

14. A multiple switch mechanism suitable for electric refrigerators comprising a normal switch in the circuit of the motor, and thermostatic mechanism for controlling said switch; and an overload switch comprising, in combination, a contact member in said motor circuit, a manually operable member for causing movement of said contact member into circuit opening and circuit closing positions and indicating by its position the open or closed condition of the contact member, said manual member affecting only said contact member and having no action on the normal switch, mechanism responsive to an excessive current for causing opening of said contact member, means effective While the excessive current condition or its effects exist to render said manually operable member inoperative to cause closing of the contact member, and means for returning the manually operable member to open circuit indicating position when such member has been moved to closed circuit indicating position while the excessive current condition or its effects persist.

15. An overload switch comprising in combination a casing, a contact member disposed in said casing and forming part of an electrical circuit, an operating member for said contact member engageable from the exterior of the casing, thermal responsive mechanism associated with said electric circuit, snap mechanism associated with said contact member and adapted to eflect rapid make and break movements of said contact member, a connection between said operating member and said snap mechanism and operable normally to effect opening and closing of the circuit upon corresponding movement of the operating member, said thermal responsive mechanism including a shaft, a ratchet wheel soldered to said shaft, and a pawl device engageable with said ratchet wheel, said snap mechanism and pawl device being so related that when the pawl device is released upon the appearance of an overload condition the contact member is thrown to open condition, said pawl device when engaged with said ratchet wheel when the latter is rigid with the shaft providing a fixed pivot'for the operating member so that movement of said member effects opening or closing of the contact, and" said pawl device, when the ratchet wheel is loose upon the shaft when overload conditions arise, taking up the movement of the operating member and preventing such member from operating the snap mechanism, whereby in the overload condition of the thermal responsive device said operating member is ineffective to close the contact member.

16. An electric switch mechanism for refrigerators comprising a casing, mechanism at least partially housed within the casing for periodically opening and closing the circuit of the motor of the refrigerator to maintain selected average temperature conditions in the refrigerator, a pair of contacts in said casing and controlling said circuit, manually controllable mechanism for causing opening and closing of said contacts including a manually reciprocable member, an overload responsive mechanism, and a support for the manual member controlled by said overload mechanism and adapted to be shifted when the current is excessive to cause opening of the contacts and to render said manual member ineffective to cause closing of the contacts while the overload conditions continue.

17. An overload switch mechanism for electric refrigerators comprising, in combination, a contact member, a snap device for operating said contact mechanism, a permanently fixed supportfor said snap device, said snap device being normally spring-biased to the open condition, manually operable mechanism for overcoming said bias and holding the snap device in contact closing position, mechanism responsive to an overload condition in the refrigerator motor circuit, and a connection between the responsive mechanism and the manually operable mechanism actuated when the current is excessive to render said manually operable mechanism ineffective on said snap device, the latter then opening the contact member through its own tension.

18. An overload switch mechanism for electric refrigerators comprising a casing, a movable contact in said casing in series with the refrigerator motor circuit, a manually operable member, a toggle device associated with said member for effecting rapid opening and closing of said contact at will, an element providing a pivotal support for said manual member, and mechanism cooperatively associated with the supporting element to cause shifting thereof and opening of the contacts upon the occurrence of an excessive current in said circuit, said manual member being then ineffective by reason of the shifting of said supporting element, to cause closing of the contacts while the overload condition continues.

19. An overload switch mechanism comprising a pair of contacts, a toggle mechanism controlling said contacts and including a pair of abutting elements, resilient supports against which the opposite ends of said elements bear, a manually operable member connected with one of said elements and movable angularly with respect there to, a support for said manual member, and mechanism acting in response to an excessive current to shift said support and cause overthrow of the manual member to the contact opening position and opening of said contacts.

20. An overload switch mechanism suitable for electric refrigerators and comprising a casing, contacts disposed in said casing in series with the refrigerator motor circuit, a snap mechanism controlling said contacts, a manually operable member engageable from the outside of the casing, a lever pivoted intermediate its ends upon a fixed fulcrum within the casing, said manual member being pivoted upon said lever to one side of said fulcrum, a spring connecting said manual member with said snap mechanism and adapted to be placed under tension and to be arranged to one side of the pivot of said member in the contact closing position of the latter so as to hold the contacts resiliently in engagement while exerting a torque on said lever tending to rotate the same, said contacts being opened when the tension in the spring is released, and mechanism for holding said lever against rotation but acting in response to an excessive current in the circuit to release said lever and cause rotation thereof by said spring with resulting release of the tension in said spring and opening of said contacts.

KATHERINE BAST. Erecutria: of the Estate 09 Frank J. Bast, ,De-

ceased.

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