US2136698A

US2136698A - Circuit controlling device

Info

Publication number: US2136698A
Application number: US63695A
Authority: US
Inventors: George H Leland
Original assignee: Leland Electric Co
Current assignee: Leland Electric Co
Priority date: 1936-02-13
Filing date: 1936-02-13
Publication date: 1938-11-15
Anticipated expiration: 1955-11-15

Description

Nov. 15, 1938. LELAND' .GIRCUIT CONTROLLING DEVICE Filed Feb. 13, 1936 5 Sheetse t l lNl/EN TUE. E'EUEEE H. LELflA/D.

/7/'5 A TTUF/VEY Nov. 15, 1938. G, H LE AND 2,136,698

' CIRCUIT CONTROLLING DEVICE Filed Feb. 13, 1936 5 Sheets-Sheet 2 hi5 A TTUE'NEY.

Nov. 15, 1938. G, H. LELAND CIRCUIT CONTROLLING DEVICE Filed Feb. 15, 1936 5 Sheets-Sheet 3 //v VE/V TUE. EEIJREE H. LELAND.

71/5 ATTUENEK Patented Nov. 15, 1938 UNITED STATES CIRCUIT CONTROLLING DEVICE George H. Leland, Dayton, Ohio, assignor to The Leland Electric Company, Dayton, Ohio, a corporation of Ohio Application February 13, 1936, Serial No. 63,695

23 Claims.

This invention relates to a circuit controlling device and is designed primarily to protect a motor or other electrical energy translating device from injury due to excessive heat.

One object of the invention to provide a thermally controlled circuit breaker which will be simple in construction, of a small compact form and inexpensive to produce.

A further object of the invention isto provide such a circuit breaker which will prevent the circuit from being closed until the thermal element has been restored to its normal condition, that is, until the temperature has fallen below the danger point.

A further object of the invention is to provide such a circuit breaker in which the controlling member will be biased in one direction by the action of the movable contactor and when moved in the other direction will impart movement to the contactor.

A further object of the invention is to provide such a circuit breaker the several parts of which will be carried by a single support and will be mounted one upon the other to provide a small 9,; compact unit and will not be liable to injury or displacement.

Other objects of the invention will appear as the device is described in detail.

In the accompanying drawings Fig. l is a transverse sectional view taken through a motor and showing the circuit controlling device in elevation; Fig. 2 is a sectional view taken through a portion of the motor on the line 22 of Fig. 1 and showing the circuit controlling device in 5 plan; Fig. 3 is a front elevation of the circuit controlling device; Fig. 4 is a section taken through the circuit controlling device on the line d-4 of Fig. 7; Fig. 5 is a section taken through the circuit controlling device on the line 55 of Fig. 7, showing the circuit closed; Fig. 6 is a section similar to Fig. 5 showing the circuit open; Fig. 7 is a longitudinal section taken through the circuit controlling device on the line 1-1 of Fig. N 3; and Fig. 8 is a longitudinal section taken on the line 88 of Fig. 3; Fig. 9 is a sectional view similar to Fig. 5, showing the circuit opened while the thermal device is operative; Fig. 10 is a sectional View similar to Fig. 5 illustrating a slight modification of the switch; Fig. 11 is a diagram of the circuit of the device shownin Figs. 1 to 6; Fig. 12 is a diagram of the circuit of the device shown in Fig. 10; Fig. 13 is a section taken through one end of the motor casing showing a modified arrangement of the switch; and Fig. 14,

is an end view of a portion of the motor casing showing the resetting device in elevation.

Circuit controlling devices embodying this invention may be used for preventing the excessive heating of apparatus of various kinds in which the heat is due to the flow of electric current through the apparatus or is controlled by an electrically operated device. Usually it is intimately associated with the apparatus in which the heat is to be controlled but this is not always essential and the controlling device may be connected at a suitable point in a circuit which controls the heat. That embodiment of the invention here illustrated is designed more particularly for controlling the heat of an electric motor and is of such a character that it will operate under the influence of long continued heat only slightly in excess of normal or will respond quickly to heat which is greatly in. excess of normal.

When used with a motor or similar energy translating device the circuit controlling device is usually mounted on the energy translating device and is preferably arranged wholly or partly within the same so as to be directly subject to the heat generated therein. As her-e shown, it is installed in a motor of ordinary construction and comprising a casing or frame 10, a stator I I, and a rotor l2 carried by a shaft l3 which is journaled in bearings at the end of the casing, one of which is shown at 14. The controlling device may be mounted in the casing in any suitable manner, as on a base I5 of insulating material. In the present instance the base carries parts other'than the controlling device and is of relatively large size and is supported on and extends on opposite sides of the bearing 14.

Mounted on the base 15 is a normally stationary but yieldable contact 16 and a movable contactor I! which is biased in circuit opening direction so that when unrestrained it will move to a position to open the circuit. In the present instance a second pair of contacts are mounted on the base and comprises a stationary but yieldable contact |6a and a movable contactor Ha, both movable contactors being under the control of the circuit controlling device. The second pair of contacts is not essential to the operation of the controlling device but when used this second pair may be connected in a branch of the same circuit in which first pair of contacts is connected or the two pairs of contacts may be connected in two phases of a three phase circuit, or with two separate circuits which are to be simultaneously controlled.

The device for controlling the position of the movable contactor, or contactors, comprises a support rigidly mounted on the base l5 and which may conveniently be in the form of a stud [8 which, in the present instance, comprises one end portion of a heat conducting rod 19 which extends through the base l5 and projects for some distance on that side thereof opposite the stud S8. A member 28 is mounted on the support 18 and serves to connect therewith other parts of the controlling device. This connecting member is held normally against movement with relation to the support by a suitable thermal element of such character that when subjected to abnormal temperature it will release the connecting memher for movement with relation to the support. This thermal element may be of any suitable character but is preferably in the form of a fusible binder 2i, such as solder having a relatively low melting point and which will quickly harden when the temperature falls below the danger point. In the present construction the connecting member 26 is tubular in form and is rotatably mounted on the stud l8, the bore of the tubular connecting member being of a diameter slightly greater than the diameter of the stud and the space between the stud and the connecting member being filled with the fusible binder. A second member 22 is also supported by the support l8 and acts on the contactor, or contactors, to control the position thereof. This controlling member 22 is held normally against movement with relation to the connecting member in circuit opening direction, that is, in a direction which will cause or permit the movable contactor, or contactors, to move to circuit opening position, and for this purpose I prefer to interpose a oneway clutch between the two members. In the particular construction illustrated the controlling member Z2 is also tubular in form, having its outor end closed, and is rotatably supported on the connecting member 20. The outer end portion of the connecting member is of reduced diameter, as shown at 23, and a spring 24 is coiled about this reduced portion of the connecting member, has one end attached to the connecting member and is in frictional contact with the inner surface of the tubular controlling member, the spring being 50 arranged that the tendency of the controlling member to rotate in circuit opening direction will expand the spring and cause the same to function as a clutch to rigidly connect the controlling member to the connecting member and thus hold the controlling member against movement in circuit opening direction with relation to the connecting member. When the controlling member is rotated in circuit closing direction this spring will contract to permit of this rotation of the controlling member with relation to the connecting member.

The controlling member is biased in circuit opening direction, preferably by the action of the movable contactor which, as above stated, is biased in circuit opening direction. The movable contactor may be of any suitable character and may be biased to circuit opening position by any suitable means. Preferably the movable contactor, or each movable contactor when two are used, comprises a resilient bar of conducting material which is supported at one end on the base IS in spaced relation to the controlling member 22, as by attaching the same to a stud 25. The other end portion of the contactor is curved about the controlling member, as shown at 26, and engages the latter on that side thereof opposite the support 25 for the contactor, the arrangement being such that, when unrestrained, the resiliency of the contactor I! will cause the same to contract and move out of engagement with the stationary contact, and the connection between the contactor and the controlling member is such that the latter Will be rotated by the contactor when the latter contracts and the contactor will be expanded and moved into engagement with the stationary contact when the controlling member is moved in circuit closing direction. The second movable i contactor Ila is similar in construction and arrangement to the conductor l8 but its supporting.

stud 21 is arranged on that side of the controlling member opposite the stud 25 which supports the contactor l1, and its curved end acts on that side 1 of the controlling member opposite the side which is engaged by the contactor ll, so that both contactors act simultaneously upon the controlling member and are moved simultaneously by the controlling member when the latter is rotated in circuit closing direction. The contactors may be connected with the controlling member in any suitable manner but preferably the controlling member is provided with radial lugs 28 which form seats with which the ends of the contactors engage.

When the controlling device is in its normal operative position, as shown in Figs. 3 to 5, the controlling member 22 holds the movable contactors in engagement with the stationary contacts and if the thermal element 2| is subjected to an abnormal temperature sufficient to render the same inoperative, as by the softening of the binder, and thus release the connecting member 29, the movable contactors are free to move under 1;

their own resilience to circuit opening position and in so moving will carry the controlling member with them, thus interrupting the circuit, as shown in Fig. 6, and permitting the temperature to which the thermal element is subjected to fall. When the temperature has fallen to such an extent that the thermal element again becomes operative to secure the connecting member to the supporting stud, as by the hardening of the fusible binder, the controlling member is rotated in circuit closing direction, that is, in a counter clockwise direction, as shown in Figs. 3 to 6, thus expanding the contactors and moving the same to circuit closing positions. The connecting member being now again rigidly secured to the supporting stud and the controlling member being held against movement by the contactors in circuit opening direction, the contactors will be retained in their circuit closing positions so long as the temperature remains normal.

Any suitable means may be provided for rotating the controlling member in a counterclockwise direction to move the contactors to circuit closing position but it is desirable that some means be provided to prevent the closing of the circuit before the temperature has fallen sufliciently to permit the thermal element to again become operative. Otherwise it would be possible for the operator to manually close the circuit and retain the motor in operation in spite of the dangerous temperature conditions. In the present construction a resetting member is provided for turning the controlling member to circuit closing position and means actuated by this member serves to positively prevent the closing of the circuit until the thermal element is in a condition to retain the removable contactors in circuit closing position. In the construction illustrated this resetting member is shown at 29 as rotatably mounted on the outer end of the controlling member 22- and is provided with radial lugs 30 arranged to engage lugs 31 on the controlling member, which extend outwardly beyond the lugs 28, when the resetting member is rotated in a counterclockwise direction and thus rotate the controlling member in circuit closing direction. The resetting member is freely rotatable with relation to the controlling member and may be retracted when the controlling member is again held against movement in circuit opening direction. The resetting member carries parts adapted to separate the movable contactors from their respective stationary contacts so long as the resetting member is in a position to hold the controlling member in circuit closing position.

As here shown, these parts are in the form of flanges 32 formed integral with the resetting member, and of insulating material, which are curved and slightly tapered in av counterclockwise direction and are so arranged that they will be moved between the movable contactor and the stationary contact of the respective pairs of contacts and thus prevent the closing of the circuit so long as they remain in that position. In the arrangement shown the flanges 32 engage the yieldable stationary contacts and move the latter to inoperative positions before the flanges enter the spaces between the stationary contacts and the movable contactors, thus retaining the stationary contacts in positions in which they cannot be engaged by the movable contactors even though the flanges do not extend entirely between the respective contact surfaces. If the resetting device is actuated to restore the movable ccntactors to circuit closing position while the thermal element is still inoperative the flanges will prevent the closing of the circuit until the resetting member is retracted and if the thermal element is inoperative the movable contactors will move to circuit opening position as the flanges are retracted and before the stationary contacts return to their normal positions. This resetting device may be also utilized to open and close the circuit while the thermal device is operative to retain the movable contactor in circuit closing position. This is accomplished by rotating the resetting device in a direction to move the controlling member to circuit closing position and thus causing the flanges to engage the stationary contacts and move the same to inoperative positions, as shown in Fig. 9. The friction between the flanges and the stationary contacts will hold the resetting device in this position until it is positively withdrawn.

The resetting member 29 may be so arranged that it can be directly engaged and actuated by the hand of the operator but when, as in the present instance, the controlling device is arranged within a sealed motor casing suitable means are provided for actuating the resetting member from the exterior of the casing without breaking the seal. As here shown, an actuating member 33 is rotatably mounted in the end wall of the casing and is connected at its inner end with the resetting member, as by a tongue and groove connection 34, and this actuating device has on its outer end a knob or other means 35 by means of which it may be manually rotated.

In Fig. 13 I have shown an arrangement of the switch whereby the resetting device can be grasped and manipulated directly by the operator without the interposition of an actuating device. As there shown, the base I is mounted close to the end wall of the casing IEI so that the resetting knob 29 projects through an opening 40 to a position in which it may be grasped by the fingers of the operator. The opening 4!! is here shown as closed by a plate 4| having an opening 42 just large enough to permit the passage of the resetting knob. The resetting knob maybe provided with any suitable means to enable it to be firmly gripped by the operator, and, as here shown, it has two lugs 43 projecting therefrom for that purpose and in the arrangement shown one of these lugs also functions as an indicator, the plate 4| being provided with oii and on indications, as shown in Fig. 14. The lugs are not necessary when an actuating device is used, as shown in Fig. 2, but in the present instance a single form of resetting knob has been used in both embodiments of the invention.

The arrangement of the controlling device within the motor casing subjects the thermal element to the heat generated in that casing during the operation of the motor and serves to protect the motor against excessive heat so generated. In thattype of motor in which a separate circuit provides a relatively large initial current for starting the motor it is desirable that means be provided to quickly render the thermal element inoperative in the event this starting current is excessive or continues for an appreoiable. length of time after the motor is in operation. For that purpose I have associated with the controlling device an electric heater which is here shown as a coil of wire 33 mounted on the heat conducting rod'iii and connected in the starting circuit so that the heat generated by the starting current will be conducted to the fusible binder by the red It. The starting circuit is controlled by a switch 3? which is actuated by a centrifugal device 38, in a well known manner, to open the starting circuit after the motor gains speed.

The heat conducting rod it may be of any suitable character but I prefer to use a material having a fairly low heat conductivity, such as brass. When the conducting rod ishea-ted by an excessive current in the starting circuit this current will, when the rod is of nigh heat conductivity, such as copper, be quickly transmitted to the fusible binder and will sometimes soften that binder just enough to release the connecting member and permit the latter to turn but will not melt the binder sufficiently to enable it to adhere tightly to the rod when it hardens and as a result the connecting member is free from the rod and the controlling device cannot be retained in its circuit closing position. By using a con ducting of a relatively low heat conductivity the inner portion of the rod, which supports the heating coil, will be heated to a temperature substantially higher than that portion thereof which carries the fusible binder and when the binder has softened and has released the connecting member heat will continue to flow from the inner portion of the rod to the outer portion of the rod, for a brief interval after the circuit has been opened, thus further raising the temperature of the outer portion of the rod and melting the binder to such an extent that it will adhere to the rod when it hardens.

The circuits of the device shown in Figs. 1 to 6 are illustrated in Fig. 11 where it will be noted that the main circuit is connected with terminals M and 55 on the base 55. The terminal it is connected by a conductor 16 with the stationary contact la and the movable contactor Ila is connected by a conductor 41 with one end of the main motor winding 48, the other end of which is connected by a conductor 49 with the terminal 45. The terminal 44 is also connected by a conductor 55 with the movable contactor I! and the stationary contact I6 is connected by a conductor 51 with one end of the heating coil 36, the other end of which is connected by a conductor 52 with the automatic starting switch 31. This starting switch is connected by a conductor 53 when one end of the starting winding 54 of the motor and the other end of that winding is connected by a conductor 55 with a terminal 45. When the motor is idle the starting switch will be closed and when the main circuit is closed, by a master switch not here shown, the current will flow through the contacts Mia and Ila and through the main winding 48. At the same time the current will flow from the terminal 44 through the contacts I? and I6, through the heating coil 35, the starting switch 37' and the starting winding 54. When the motor has gained speed the starting switch will automatically open to interrupt the flow or" current through the starting winding 54 but the current will continue to flow through the main winding 48.

In Fig. 16 I have illustrated a slight modification of the invention in which the movable contactor of one pair of contacts and the stationary contact of the other pair are supported by a single terminal stud and are preferably formed in one piece. As there shown, the movable contactor 56 which cooperates with a stationary contact 5'? is formed integral with the stationary contact 58 which cooperates with the movable contactor 59, the contactor 59 and contact 5'! being also formed integral. The

contacts

56 and 58 are mounted on and preferably rigidly secured to terminal stud 65, and the contactor 59 and r the contact 5'! are likewise mounted on a single terminal stud 5|. With this exception the construction and operation are similar to those above described, the controlling mechanism comprising the controlling member 22 which is connected with the connecting member 20 by the spring clutch 24 and is secured to the supporting stud M3 by a fusible binder 23, and resetting knob is similar to that heretofore described but the flanges 32 only thereof are shown in Fig. 10. A

circuit for this form of switch is shown in Fig. 12

where the line conductors are shown as connected with

terminals

62 and 63. The terminal 62 is connected by a conductor 64 with the terminal stud 55 of the switch and the terminal stud BI is connected by a conductor 65 with one end of the main motor winding 65, the other end of that winding being connected by a conductor 61 with the terminal 63. The terminal 6| is also connected, by a conductor 68, with a heating coil '39, similar in construction and arrangement to the heating coil 36, and the other end of the heating coil is connected by a conductor 10 with the automatic starting switch 3'1. The starting switch is connected by a conductor II with one end of the starting winding 12 of the motor, the other end of which is connected by the conductor 72 with the terminal 63. Thus the current flows from the terminal 62 to the terminal stud 60 where it divides, a portion of the current flowing through the

contacts

58 and 59 in the winding 68, and another portion flowing through the contacts 56-5l, heating coil 69, starting switch 31 and starting winding 12. When the motor gains speed the automatic starting switch will open the starting circuit and thereafter the current will flow only through the

contacts

58 and 59 to the main winding 56.

While I have shown and described one embodiment of my invention and minor modifications thereof I wish it to be understood that I do not desire to be limited to the details thereof as various modifications may occur to a person skilled in the art.

Having now fully described my invention, what I claim as new and desire to secure by Letters Patent, is:

1. In a circuit controlling device, a movable contactor biased in one direction, a rod extending transversely to the path of movement of said contactor and held against rotation, a controlling member rotatably mounted on said rod and so connected with said contactor that the rotation of said controlling member in one direction will move said contactor in opposition to its bias and the movement of said contactor in the direction of its bias will rotate said controlling member in the other direction, said contactor constituting the sole means for moving said controlling means in the last mentioned direction, a connecting member rotatably mounted on said rod adjacent to said controlling member, means including a thermal element to hold said connecting member normally against rotation and to release the same for rotation by said contactor when said thermal element is subjected to an contactor acting on said controlling member to rotate the latter in the other direction when said contactor moves in the direction of its bias, and a one-way clutch connecting said members and holding said controlling member against rotation by said contactor with relation to said connecting member.

3. In a circuit controlling device, a movable contactor, a supporting bar, a tubular connecting member rotatably mounted on said bar and secured thereto by a fusible binder, a tubular member rotatably mounted on said connecting member, biased in one direction and acting on said contactor to control the position thereof, and a one-way clutch interposed between said members to hold said controlling member against rotation in said direction with relation to said connecting member.

4. In a circuit controlling device, a movable contactor biased in one direction and controlling means for said contactor comprising a supporting bar fixed against rotation, a tubular connecting member rotatably mounted on said bar, a fusible binder to hold said connecting member normally against rotation on said bar, a tubular controlling member rotatably mounted on said connecting member and acting on said contactor to control its position, and a one-way clutch interposed between said members to hold said controlling member against rotation by said contactor with relation to said connecting member.

5. In a circuit controlling device, a movable contactor biased in one :'direction and controlling means for said contactor comprising a supporting bar fixed against rotation,a tubular connecting member rotatablymounted on said bar, a fusible binder to hold said connecting. member normally against rotation on said bar, a tubular controlling member rotatably mounted about said connecting member and acting on said contactor to control its position, a one-way clutch interposed between said members to hold said controlling member against rotation by said contactor with relation to said connecting member and to cause both membersto be rotated in one direction by said contactor when saidbinder is softened, and means carried by and movable with relation to said controlling member for rotating the same inthe other direction with relation to said connecting member to restore said contactor to its initial position.

6..In a circuit controlling device, a normally stationary contact, a. movable contactor cooperating with said stationary contact, a supporting bar, a member movably mounted on said bar, acting on said contactor to control the position thereof and biased in circuit opening direction, means including a fusible binder to hold said controlling member normally against movement on said bar in circuit opening direction and to release the same for such movement when said binder softens, and a device carried by said bar to move said controlling member to circuit closing position and having a part to prevent said movable contactor from engaging said stationary contact while said binder is soft.

7. In a circuit controlling device, a normally stationary contact, a movable contactor cooperating with said stationary contact, a supporting bar, a member rotatably mounted on said bar, acting on said contactor to control the position thereof, and biased in circuit opening direction, means including a thermal element to normally hold said controlling member against rotas tion on said bar in circuit opening direction and to release the same for such rotation when said thermal element is subjected to an abnormal tem perature, a device rotatable about an axis extending lengthwise of said bar and acting on said controlling member to rotate the same in circuit closing direction, and a part actuated by said rotatable device to prevent said movable contactor from engaging said stationary contact while said holding means is inoperative to retain said controlling member in circuit closing position.

8. In a thermal switch, a movable contactor biased in one direction, controlling means for said contactor comprising a support, a connecting member rotatably mounted on said support, thermal means for holding said connecting member normally against rotation and for releasing the same under abnormal temperature conditions, a controlling member rotatably mounted on said connecting member and acting on said contactor to control the position thereof, and a coiled spring wound about said connecting member between the same and said controlling member and serving as a clutch to hold said controlling member against rotation by said contactor with relation to said connecting member.

9. In a circuit controlling device, a rotatable controlling member having a seat on one side thereof, a resilient contactor biased to circuit opening position, having one end fixed to a support on that side of said controlling member opposite said seat and. having its other end portion. curved about said controlling member and engaging said seat to maintain said resilient contactor under tension when it is in its circuit closing position, andmeans including a thermal element for holding said controlling member normally in a position to retain said contactor in circuit closing position and to release said controlling member for movement by said contactor when said thermal element is subjected to an abnormal temperature.

16. In a circuit controlling device, a rotatable controlling member, two resilient contactors fixedly mounted on a support on opposite sides of said controlling member and each biased to circuit opening position, each contactor having a portion curved about said controlling member and connected with that side thereof opposite the support for said contactor to maintain said contactor under tension when it is in its circuit closing position, whereby said contactors will rotate said controlling member in one direction as they move to their circuit opening positions and the rotation of said controlling member in the other direction will move said contactors to circuit closing positions, and means including a thermal element for holding said controlling element normally against movement by said contactors and for releasing said controlling member for movement by said contactors when said thermal element is subjected to an abnormal temperature.

11. In a circuit controlling device, a normally stationary contact, a movable contactor cooperating with said stationary contact, means including a thermal element to hold said movable contactor normally in circuit closing position and to release the same for movement to circuit opening position when said'thermal element is subjected to an abnormal temperature, a rotatable resetting element acting on said movable contactor to move the same toward its circuit closing position, a part movable with said rotatable element into and out of a position between said movable contactor and said stationary contact to prevent the closing of said circuit until said holding means is operative to retain said movable contactor in the position to which it has been moved by said rotatable element when the latter is withdrawn.

12. In a circuit controlling device, a normally stationary contact, a movable contactor cooperating with said stationary contact, means including a thermal element to hold said movable contactor normally in circuit closing position and to release the same for movement to circuit opening position when said thermal element is subjected to an abnormal temperature, a rotatable resetting element acting on said movable contactor to move the same to circuit closing position, and means actuated by said rotatable element to move said stationary contact to an inoperative position when said movable contactor isv moved to circuit closing position and to prevent the closing of the circuit so long as said rotatable element is in a position to hold said movable contactor in circuit closing position.

13. In a circuit controlling device, a normally stationary contact, a movable contactor cooperrating with said stationary contact and biased to circuit opening position, a movable member to control the position of said movable contactor, means including a thermal element to hold said controlling member normally against movement in a direction to permit said movable contactor to move to circuit opening position and to release the same for such movement when said thermal element is subjected to an abnormal temperature, and a device moving with said controlling member when the latter is moved in circuit closing direction to prevent said contactor from engaging said stationary contact and movable independently of said controlling member to permit said contactor to engage said stationary contact only when said thermal element is operative to hold said controlling member against movement in circuit opening direction.

14. In a circuit controlling device, a normally stationary contact, a movable contactor cooperating with said stationary contact and biased to circuit opening position, a rotatable member to control the position of said movable contactor, means including a thermal element to hold said controlling member normally against rotation in a direction to permit said movable contactor to move to circuit opening position and to release the same for such movement when said thermal element is subjected to an abnormal tempera ture, and a device rotatable about an axis parallel with the axis of said controlling member to move said controlling member in circuit closing direction and having a part movable therewith to prevent said contactor from engaging said stationary contact until said device is actuated to move said part to inoperative position and said thermal element is operative to hold said controlling member against movement in circuit opening direction.

15. In a. circuit controlling device, a normally stationary contact, a movable contactor cooperating with said stationary contact and biased to circuit opening position, a rotatable member to control the position of said movable contactor, means including a thermal element to hold said controlling member normally against rotation in a direction to permit said movable contactor to move to circuit opening position and to release the same for such movement when said thermal element is subjected to an abnormal temperature, a device rotatable in one direction about an axis susbtantially coincident with the axis of said controlling member to move said controlling member in circuit closing direction, and a part carried by said rotatable device and movable by said rotation thereof into a position between said movable contactor and said stationary contact, said device being rotatable in the other direction with relation to said controlling member to withdraw said part.

16. In a circuit controlling device, a normally stationary contact, a movable contactor cooperating with said stationary contact and biased to circuit opening position, a rotatable member to control the position of said movable contactor, means including a thermal element to hold said controlling member normally against rotation in a direction to permit said movable contactor to move to circuit opening position and to release the same for such movement when said thermal element is subjected to an abnormal temperature, a device mounted for rotation about the axis of and with relation to said controlling member and, when rotated in one direction, acting on said controlling member to rotate the latter in circuit closing direction, and means controlled by said device to prevent the closing of said circuit when said device moves said controlling member in circuit closing direction.

17. In a circuit controlling device, a normally stationary contact, a movable contactor cooperating with said stationary contact and biased to L i r,

circuit opening position, a rotatable member to control the position of said movable contactor, means including a thermal element to hold said controlling member normally against rotation in a direction to permit said movable contactor to move to circuit opening position and to release the same for such movement when said thermal element is subjected to an abnormal temperature, a device mounted for rotation about the axis of and with relation to said controlling member, and, when rotated in one direction, acting on said controlling member to rotate the latter in circuit closing direction, and a part carried by said device and arranged to prevent said contactor from engaging said stationary contact when said device is rotated in one direction and to be moved to an inoperative position when said device is rotated in the other direction.

18. In a circuit controlling device, a movable contactor, a support, a connecting member rotatably mounted on said support, a thermal element to hold said member normally against rotation with relation to said support, a controlling member rotatably mounted about said connecting member, biased in one direction and acting on said contactor to control the position thereof, and a spring coiled about said connecting member, attached at one end thereto and acting on said controlling member to hold the latter against rotation in said direction with relation to said connecting member.

19. In a circuit controlling device, a normally stationary contact, a movable contactor cooperating with said stationary contact, a support, a member rotatably mounted on said support, acting on said movable contactor to control the position thereof and biased in circuit opening direction, means including a thermal element to normally hold said controlling member against rotation in circuit opening direction and to release the same for such rotation when said thermal element is subjected to an abnormal temperature, a rotatable device acting on said controlling member to rotate the same in circuit closing direction, and a part connected with said rotatable device and arranged to be moved between said movable contactor and said stationary contact when said rotatable device moves said controlling member to circuit closing position,

20. In a circuit controlling device, a normally stationary contact, a movable contactor cooperating with said stationary contact, a supporting stud, a connecting member rotatable on said stud and secured thereto by a fusible binder, a second member rotatably supported by said stud, acting on said movable contactor to control the position thereof and biased in circuit opening direction, clutch means to hold said controlling member against rotation in circuit opening direction with relation to said connecting member, a third member rotatably supported by said stud and having means to rotate said controlling member in circuit closing direction, and a part carried by said third member and arranged to be moved between said movable contactor and said stationary contact when said third member moves said controlling member to circuit closing position.

21. In a circuit controlling device, a normally stationary contact, a movable contactor cooperating with said stationary contact, a supporting stud, a connecting member rotatable on said stud and secured thereto by a fusible binder, a second member rotatably supported by said stud, acting on said movable contactor to control the position thereof and biased in circuit opening direction, clutch means to hold said controlling member against rotation in circuit opening direction with relation to said connecting member, a third member rotatably supported by said stud and having means to rotate said controlling memher in circuit closing direction, and a part carried by said third member and arranged to move said stationary contact to an inoperative position when said third member moves said controlling member to circuit closing position.

22. In a circuit controlling device, a normally stationary contact, a movable contactor coopcrating with said stationary contact, a supporting stud, a tubular connecting member mounted on said stud and held normally against rotation thereon by a fusible binder, a tubular member rotatably mounted on said connecting member, acting on said movable contactor to control the position thereof and biased in circuit opening direction, a one-way clutch to hold said controlling member against rotation in circuit opening direction with relation to said connecting member, a third member rotatably mounted on said controlling member and having means to rotate the latter to circuit closing position, and a part carried by said third member and arranged to be moved between said movable contactor and said stationary contact when said third member moves said controlling member to circuit closing position.

23. In a circuit controlling device, a normally stationary contact, a movable contactor cooperating with said stationary contact, a support, a member rotatably mounted on said support, acting on said movable contactor to control the position thereof, and biased in circuit opening direction, means including a thermal element to normally hold said controlling member against rotation in circuit opening direction and to release the same for such rotation when said thermal element is subjected to an abnormal temperature, and a rotatable device acting on said circuit controlling member to rotate the same in circuit closing direction, said rotatable device being movable with relation to said controlling member and having a part arranged to move said stationary contact to an inoperative position when said rotatable device is rotated in one direction while said controlling member is in circuit closing position.

GEORGE H. LELAND.