US2538080A - Thermostatic switch - Google Patents

Description

Patented Jan. 16, 1951 mesne assignments, to Adrian Medert, Cleveland; Ohio, and Russell Bolesky, Mansfield,

Ohio, as trustees- Application october 1s, 1Q48, Seria l No. 54,280

14 Claims. (or 200-1138) This invention relates to thermostatic circuit breakers, and more particularly to thermostatically Controlled. switch sa. J1 h like,

It. is among the objects of the present invention to provide anew and novel thermostatically controlled switch which is adaptedv to interrupt or pen an electric circuit. automaticalhr on rise of temperature to a predetermined point and requiring. manual, actuation to close the, circuit after ithas been so ope1r,1 ed -.v

Another object of the invention is to provide in a thermal responsive device a thermal; element having two positions of concavity, which element is free to pass automatically from its first position to. its second position up n. a ch ng i perature and is. caused to actuate a switch in its second position and is free to return to its, first position upon a. subsequent change in temperature.

Another object of my invention is the provision of a manual reset thermostatic switch of this character wherein the switch mechanism is trip-free of the manual resetv lever.

A further obiect of my invention is the provision of resetting mechanism for a thermostatic device of the class described wherein the reset lever serves as an indicator of the position of the switch within the device.

A still further object of the invention is to provide a thermal responsive device having a switch member for controlling a circuit through the device actuated by a thermal element having two positions of concavity which element is free to pass automatically from its opposed positions of concavity and is caused to actuate the switch to open the circuit in one of said positions and manually operable mechanism for securing the switch in circuit open position.

A still further object of the invention is to provide .a thermal responsive device having a manvuallyeactuated member for resetting a switch controlling a circuit through the device wherein the 7 switch is free to open and close the circuit in the event the reset member becomes inoperable.

A further object of'the invention is to provide .a thermal responsive device embodying switch ,means arranged to control a plurality of circuits of operation is particularly adapted as a protective device in controlling circuits wherein the current is employed for heating purposes,

These and other objects and advantageous features of the invention not at this time more pare ticularly pointed out will" become more apparent as the nature of the invention is better understood from the following detailed description taken in conjunction with the accompanying drawings wherein like reference characters dc.- note corresponding parts, and wherein:

Figure 1 is a front elevational View of a thermostatic control device embodying the present invention;

Figure 2 is a, side elevational view of the device of Figure 1-;

Figure 3 is a rear view of the device shown Figure l with the thermostatic element removed;

Figures 4 and 5 are sectional views taken n the; lines 4-4 and 5:5, respectively of Figure, 3:;

Figures 6 and 7 are enlarged longitudinal medial sectional views taken on the line 6.- '.6 of Figure 1- illustrating the, elements of the device in circ i os and cir t n n pcs t o reective v; I

Ei ure 5 a e r plan view or the device similar tov Mature 3, with the, thermoel ent in. onerative position; and

Figure 9 is a schema c l ctrical circuit diar m i l in the devi e of he present in.- vention applied to a pa tus em od ing. a th rmostatically controlled electrica heating e me t,

With. r ierence o. he accompany dr win there s llustra ed a th mostat ally contro ed device ambodying a switch for controlling an electrical circuit made in'accordance with the present invention and comprising asubstantially rectangular housing I!) having laterally out- Wardly extending ears H and i2 formed on the opposed ends thereof suitably aperturedas at [3 to receive screws or other securing means (not shown) for attaching the device to a suitable support or to the apparatus with which it is to function. The housing lll is preferably made of an electrical insulating material which is heat resistant to a fair degree, such as a phenolic condensation product or the like. The face [5 of the housing 10 is formed with a transverse upstanding boss 16, intermediate the extremities of which there are provided lateral projections IT. One end of the boss I6 is notched or cut away to a point below the face [5 to provide a slot l8, the

purpose of which will appear hereinafter.

arm 35 within the housing section 2|.

opposed slots 25 midway between the extremities thereof. The sections 20 and 22 are similarly formed each having a centrally positioned substantially rectangular depressed portion 26 in which there is provided a bore 21 extending into the body portion of the lateral projections Mounted in the bore 21 is a coil spring 29, one end of which bears against the base of the bore 21 and the other against the lower surface of a bridging contact 30 seated within the depressed portion 26 and substantially filling the same. Adjacent each end of the sections '20 and 22 there is formed an aperture '28 the outer end of which is countersunk to receive the head of a terminal post 3| mounted in the aperture. Each of the posts 3| is provided with a threaded bore adapted to receive the usual binding post 32 to which lead wires are secured. Secured to the inner ends of each of the terminal posts 3| are contact elements 33 seated within the ends of the sections 2|! and 22 and arranged to overlie and be engaged by the bridging contact 30.

The central section 2| of the interior of the housing In is depressed into the boss l6 below the outer surface of the face of the housing and receives therewithin a longitudinally slidable reset arm 35 (see Figures 3 and 5) the outer end of which proiects through the housing into the slot I6 and may be extended beyond the side of the housing In. The reset arm 35 is provided with an elongated slot 36 the outer portion 31 thereof being of greater width and defining a shoulder '38. The inner end of the reset arm 35 is formed with an upstanding lug or flange 39 through which extends an aperture 40. The housing section 2| is provided with s aced apertures 4| and 42 extending through the face of the housing Ill. Mounted in the apertures 4| and 42 are rivets 43 and 44, respectively, which project through the elongated slot 36 of the reset arm 35 and are provided with heads which overlie the reset arm 35 and retain it in slidable position within the section 2|. shouldered portions formed on the rivets 43 and 44 below the heads thereof permit the free reciprocation of the reset The rivet 44 is extended beyond the head thereof to form an upstanding post 45. Extending between aperture 4!] in the flange 39 and the post 45 is a spring 46 which serves to normally urge the reset arm 35 outwardly and project the end thereof beyond the wall of the housing IIJ.

For moving the bridging contact 30 out of engagement with the adjacent contact elements 33 and thereby breaking the circuit thereto there is provided contact actuator 50, which similar to the housing H), is made of electrical insulating material. As best shown in Figures 3 and 6 of the drawings the contact actuator 50 comprises a body portion substantially square in crosssection and formed with outwardly extending feet members 52 the outer extremities of which are adapted to engage the upper surface of the bridging contacts 30 in each of the sections and 22. Pressed into a slot 53 extending into the interior of the body 5| is a catch member '54 provided with serrated edge portions 5-5 which serve to. prevent the withdrawal of the member 54 from the slot 53. The member 54 is provided with an elongated opening 56 through which the wire connecting the spring 46 to the post 45 is adapted to pass. Inwardly extending opposed slots 51 are formed in the edge portions of the catch member 54 adjacent the lower extremity thereof. W en 4 0 the contact actuator 55 is mounted in the section 2| the lower end of the catch member 54 is adapted to extend into a suitable recess 58 of a predetermined depth formed in the lower surface of central section 2| which serves to guide and limit the downward movement of the contact actuator. When'the reset arm 35 is disposed in its innermost position the lower extremity of the member 54 is freely movable through the portion 31 of the slot 36 formed in the reset arm 35. When the member 3-5 is projected outwardly the edge portions of the slot 36 at its narrow extremity are received within the cutaway portions 51 in the member 54 (see Figure '7) thereby preventing the member 54 and the contact actuator 50 to which it is secured, from moving upwardly in response to the pressure of the springs '29 upon the bridging contacts 30 bearing against the feet member 52 of the contact actuator 50 after it has been moved to such position as hereinafter de scribed.

On the upper surface of the contact actuator member 5|) there is provided a bumper button 66 which is adapted to be engaged by a composite thermostatic plate 6|. The thermostatic plate 6| may be a dished bimetallic snap-acting thermostatic element being characterized in that its central portion has one position of stable equilibrium when it is cold and another relatively stable position of equilibrium when it is hot, the hot and cold positions having Opposite curvatures. As illustrated in Figure 6 the thermostatic element 6| is shown when the same is cold having an outward curvature, and in Figure 7 the element is illustrated in the position taken when it is hot, being curved inwardly and engaging the bumper button 60. The thermostatic plate 6| is circular and the edge thereof is adapted to be received within shouldered portions 62 of the housing I0 adjacent the ears II. A mounting plate 63 having a configuration complemental to the rear surface of the housing Ill and formed with a peripheral flange 64 which engages the side of the housing ||i thereabout serves to maintain the plate 6| on the rear face of the housing ID. Ears 65 formed integrally with the flange 64 of a length to extend beyond the thickness of the ears H are adapted to be bent thereover to hold the mounting plate 63 in position. The mounting plate 63 is provided with a circular opening 66 the edge portion of which overlaps and confines the edge of the thermal plate 6|. The central portion of plate 6| freely moves between its positions of opposite concavity in response to changes in temperature and serves to move the contact actuator as it moves from its first position of concavity as shown in Figure 6 to its second position as shown in Figure 7.

The thermostatically controlled switch of the present invention is particularly adaptable for use with apparatus employing electric current for heating purposes, serving to interrupt the circuit when the temperature of the device reaches a predetermined degree. The thermostatic switch in such cases may serve as a safety device in the event that the normal controlling devices fail to function properly thereby preventing overheating and damage to the apparatus. With reference to Figure 9 of the drawings the thermostatic control device of my invention is schematically illustrated in the circuit of a heating element which may be incorporated in apparatus such as a Water heater. The numerals l0 and H designate power lines and numerals I2 and 13 indicate diagrammatically a thermostat and a. heater, respectively.

A conductor 14 connects the power line TI] to one terminal 32 of one switch of the device A. A conductor 15 connects the other terminal 32 to one terminal of the thermostat 12 which in turn is connected to heater element 13 by conductor 16. A conductor 11 leads from the heater element I3 to the terminal 32 of the second switch of the device A which is connected to the other power line H by conductor 18. Tracing the circuit with the switches of the device A closed it will be seen that power passes from the supply line through conductor 74 to terminal 32, contact element 33, across bridging contact 30 to the other contact element 33 thence out through the terminal 32 connected thereto, conductor 15 to terminal 80 of thermostat 12, through thermostat 12 to terminal 81, thence through conductor 16 to terminal 82 of heater element 73, through heater element 12 to terminal 83, thence through conductor TI to terminal 32 of the second switch of the device A, contact element 33, across bridging contact 30 to other contact element 33, out through terminal 32 connected thereto and thence through conductor 78 to power line H. The elements of the device A when in this position are illustrated in Figure 6 of the drawings. Upon the occurrence of a temperature condition of a predetermined degree causing a rise in the temperature of the thermostatic plate 6 i above its stable position as shown in Figure 6, it snaps into the position shown in Figure 7 in which the concavity of the plate 6! is opposite to that shown in Figure 6. When the thermostatic element 6! snaps into this position, the center thereof engages the bumper button 60 on the contact actuator 50 moving the same downwardly. Movement of the contact element downwardly moves the bridging element 36 out of engagement with its adjacent contact elements 33 thereby breaking the electrical circuit. Movement of the contact actuator 50 downwardly brings the slotted portion of the element 54 into registry with the slot 36 in the reset arm 35 thereby permitting the arm 35 to be moved outwardly in response to the action of the spring .6. The outer end of the arm 35 is thus projected beyond the wall of the housing It] as shown in dotted lines in Figure 3 and when so positioned indicates that the contacts of the switch are open and the circuit broken. As shown in Figure '7, the lower extremity of the member 54 is locked beneath the reset arm 35 when the same is in its extended position thereby holding the bridging element 30 from engagement with the contact elements 33 upon movement of the thermostatic element 6! to its initial position It is to be noted that if the reset arm 35 fails or is prevented from moving outwardly and thereby latching the contact actuator in switch open position the device will still operate to open the circuit. The contact actuator will, in such case, follow the thermostatic plate 6| as it automatically snaps from one position of concavity to its opposite position in response to temperature changes and will open and close the circuit through the device. Thus the action of the thermostatic plate is free from the switch and the switch is always opened when the thermostatic plate moves into its second position of concavity.

Having thus described my invention so that persons skilled in the art may understand and practice the same, what I desire to obtain by Letters Patent is embodied in the appended claims.

I claim:

1. A thermostatic control device comprising a housing, an electric switch within said housing including a plurality of stationary contacts and a contact movable into and out of contact with said stationary contacts, a contact actuator member engageable with said movable contact, a snap acting thermostatic plate having its peripheral edge portion confined in said housing, said thermostatic plate having two oppositely facing positions of stability in one of which positions its central portion is adapted to engage and act against said actuator member and simultaneously open all of the contacts of said switch, manually operable means movable relative to said actuator member, and spring means urging said manual means to an extended position exterior of said housing, said manual means serving to maintain said actuator member in switch opening position upon movement thereof to its extended position.

2. A thermostatic control device comprising a housing, an electric switch within said housing, a contact actuator member movable to open said switch, a snap acting thermostatic plate peripherally mounted on said housing and having two positions of stability, said thermostatic plate passing automatically from its first position to its second position of stability upon change of temperature to a predetermined degree, said thermostatic plate in its second position adapted to have its central portion engage and move said contact actuator and open said switch, means engageable with said contact actuator for maintaining the same in open switch position, and manual means for releasing said contact actuator and permitting the switch to close.

3. A thermostatic control device comprising a housing, an electric switch within said housing, a contact actuator member movable to open said switch, a snap acting thermostatic plate having its peripheral edge portion confined in said housing and having two positions of stability, said thermostatic plate passing automatically from its first position to its second position of stability upon change of temperature to a predetermined degree, the central portion of said thermostatic plate in its second position adapted to engage and move said contact actuator and open said switch, and means engageable with said contact actuator -for maintaining the same in open switch position,

said means including a slidable lever and spring means for urging said lever to an extended position exterior of said housing.

4. A thermostatic control device comprising a housing, an electric switch within said housing, a

contact actuator member movable to open said switch, a snap acting thermostatic disc having its peripheral edge portion confined in said housing and having two positions of stability, said thermostatic disc passing automatically from its first engagement with said contact actuator and retain the contact actuator against return movement irrespective of the position of the thermostatic plate.

5. A thermostatic control device comprising a housing, an electric switch within said housing, a contact actuator member movable to open said switch, a snap acting thermostatic plate having its peripheral edge confined in said housing having two positions of stability and arranged to pass automatically from its first position to its second position of stability upon change of temperature to a predetermined degree, the central portion of said thermostatic plate upon moving to said second position adapted to engage and move the contact actuator and open said switch, and means operable independently of said thermostatic plate upon said contact actuator for securing the same in open switch position.

6. A thermostatic control device comprising a housing, an electric switch within said housing including a plurality of stationary contacts and a contact movable into and out of contact with said stationary contacts, a contact actuator member engageable with said movable contact, a snap acting thermostatic plate having its peripheral edge portion confined in said housing and having two positions of stability, said thermostatic plate passing automatically from its first position to its second position of stability upon change of temperature to a predetermined degree and upon such movement the central portion thereof is adapted to engage the contact actuator member and simultaneously open the contacts of said switch, manually operable means movable relative to said contact actuator member, and spring means urging said manual means to an extended position exterior of said housing, said manual means serving to maintain said contact actuator member in switch opening position upon movement thereof to its extended position.

7. A thermostatic control device comprising a housing, an electric switch within said housing including a plurality of stationary contacts and a contact movable into and out of contact with said stationary contacts, a contact actuator member engageable with said movable contact, a snap acting thermostatic plate having its peripheral edge portion confined in said housing and having two positions of stability, said thermostatic plate being free to move automatically from its first position to its second position of stability upon change of temperature to a predetermined de gree independently of the switch elements and upon such movement to engage the contact actuator member and simultaneously open all of the contacts of said switch, and manually operable means movable in response to movement of said contact actuator to secure the switch in open position.

8. A thermostatic control device comprising a housing, an electric switch within said housing including a plurality of stationary contacts and a contact movable into and out of contact with said stationary contacts, means for maintaining said stationary and movable contacts in engagement, a contact actuator member engageable with said movable contact, a snap acting thermostatic plate having its peripheral edge portion confined in said housing and having two positions of stability, said thermostatic plate being independent of the said switch and free to pass automatically from its first position to its second position of stability upon change of temsuch movement to engage and move the contact actuator member and open the contacts of said switch, manually operable means responsive to the movement of said contact actuator for securing th switch in open position, and means for releasing the contact actuator and closing the switch.

9. A thermostatic control device comprising a housing, an electric switch within said housing including a plurality of stationary contacts and a contact movable into and out of contact with said stationary contacts, a contact actuator member engageable with said movable contact, a snap acting thermostatic plate having its peripheral edge portion fixedly secured in said housing and its central portion being free to assume positions of opposite concavity in one of which positions it it adapted to act against said contact actuator member and open the contacts of said switch, and means operable upon said contact actuator member for securing the same in open switch position.

10. A thermostatic control device comprising a housing, an electric switch within said housing including a plurality of stationary contacts and a contact movable into and out of contact with said stationary contacts, means for maintaining said stationary and movable contacts in engagement, a contact actuator member engageable with said movable contact, a snap acting thermostatic plate having its peripheral edge portion rigidly secured in said housing and its central portion free to assume positions of opposite concavity in one of which positions it is adapted to engage and act against said contact actuator member and open the contacts of said switch, and means responsive to movement of said contact actuator for securing the switch in open position, said means adapted to be manually actuated to close the switch upon return of said thermostatic plate to its first position.

11. A thermostatic control device comprising a housing, an electric switch within said housing including a plurality of stationary contacts and a contact movable into and out of contact with said stationary contacts to complete a circuit thereacross, a contact actuator member engageable with said movable contact, a snap acting thermostatic plate movable independently of said switch and operably positioned with respect to said contact actuator, said thermostatic plate having its peripheral edge portion confined and its central portion capable of snapping between positions of opposite concavity under changing ambient temperature whereby the contact actuator is caused to open said switch contacts, manually operable means movable relative to said contact actuator member, and spring means urging said manual means to an extended position exte rior of said housing, said manual means including means for maintaining said contact actuator member in switch opening position upon movement thereof to its extended position.

12. A thermostatic control device comprising a housing, an electric switch within said housing including a plurality of stationary contacts and a contact movable into and out of contact with said stationary contacts to complete a circuit thereacross, means for maintaining said stationary and movable contacts in engagement, a contact actuator member engageable with said movable contact, a snap acting thermostatic plate freely movable relative to said switch and operably positioned with respect to said contact actuator, said thermostatic plate having its pea ripheral edge portion confined and its central portion capable of snapping between positions of opposite concavity under changing ambient temperature and to engage and move the contact actuator to open said switch contacts, a manually operable arm slidably mounted relative to said contact actuator member, and spring means for urging said arm to an extended position exterior of said housing, said arm engageable with said contact actuator member upon movement thereof to its extended position and serving to hold the same in such position irrespective of the position of the thermostatic plate until the arm is manually returned to initial position within the housing.

13. A thermostatic control device comprising a housing, spaced switches mounted within said housing embodying opposed contacts, a contact actuator bridging the space between said, switches and. movable to open the contacts of said switches, a snap acting thermostatic plate confined at its periphery in said housing with its central portion having two positions of stability, said thermostatic plate passing automatically from its first position to its second position of stability upon change of temperature to a predetermined degree, said thermostatic plate in its second position arranged to have its central portion engage and move said contact actuator and open the contacts of said switches, said contact actuator being adapted to maintain the switches in open position and, manually operated means for re- 10 leasing said contact actuator and permitting the contacts of said switches to close.

14. A thermostatic control device comprising a housing, spaced switches mounted within said housing embodying opposed contacts, a contact actuator bridging the space between said switches and movable to open the contacts of said switches, a snap acting thermostatic disc confined at its periphery in said housing with its central portion free to assume opposite positions of con- 6 cavity, said thermostatic disc passing automatically from its first position to its second position of concavity upon change of temperature to a predetermined degree, said thermostatic plate in its second position adapted to have its central portion engage and move said contact actuator to open the contacts of said switches, and manually operable means effective to release said contact actuator and permit the contacts of said switches to close.

JOHN D. BOLESKY.

REFERENCES CITED The following references are of record in the file of this patent:

UNITED STATES PATENTS

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