US2083508A - Circuit breaker - Google Patents

Description

L. SCHMIDT CIRCUIT BREAKER June 8 1937.

5 Sheets-Sheet 1 Filed June 18, 1955 l'snnentor LPMQERTS H NOT b tton g 1.. SCHMIDT 2,083,508

0 IRCUIT BREAKER June 8, 1937.

Filed June 18, 1935 3 Sheets-Sheet 2 INVENTOR.

L. SCHMIDT June 8, 1937.

CIRCUIT BREAKER 3 Sheets-Sheet 5 Filed June 18, 1955 Patented June 8, 1937 CIRCUIT BREAKER Lambert Schmidt, Leeds, N. Y.

Application June is,

17 Claims.

This invention relates to circuit breakers, and more particularly circuit breakers of the Edison plug type, and has for its object the provision of a circuit breaker which may readily act by thermostatic means, or by manual means to break the circuit. For this purpose, in some embodiments, the central switch rod passes through a plate having an opening of substantially the diameter of the switch rod, which plate is inclined to the axis of the switch rod and then locks against the plate edge, and holds the switch rod in circuit-closed position. When the current in the circuit exceeds a, normal amount, a thermostatic control in circuit therewith is operated,

and this presses upon the plate and moving it downwardly, disengages the edge of the plate from the periphery of the central switch rod, and thereafter the switch rod under the action of a spring releases itself from circuit-closed position,

,, and breaks the circuit. Or, manual means may be provided which, if pressed downwardly, re-

leases the plate in the same manner.

In other embodiments, the thermostatic control is arranged to surround the switch rod and performs the function of frictionally holding the switch rod, but upon the current exceeding a normal amount, then releasing the switch rod. This thermostatic control acting in this double capacity can be arranged to act on the switch rod along any portion of the same.

The principle of the invention consists in looking the central switch rod in circuit closed position, by a means surrounding the same, and then moving said locking means in respect to said rod,

thereby disengagingwhe rod from the rod-holding means. The parts are assembled in a very compact manner and thus may be readily utilized in a standard cut-out. The button in certain embodiments may be suitably colored to show circuit on or circuit ofi positions.

An object of the invention, accordingly, is to provide a circuit breaker in which the thermal responsive element is a part of the electric cir-' cuit of the device and also constitutes a mechanical clutch mechanism.

A further object of the invention is to provide,

in combination with a circuit breaker of the: above character, an improved shunt mechanism by means of which arcing across the mainbreaker contacts may be eliminated.

A further object of the invention is to pro vide a circuit breaker of the above character wherein the thermal element is formedof bimetal and functions not only as one of the breaker contacts, but also as a clutch by means of which 1935, Serial No. 27,175

(or. ecu-11s) the breaker contacts may be maintained in a closed position.

A further object of the invention is to provide, in combination with a circuit breaker of the type above mentioned, shunt mechanism which is mounted on the bottom terminal member.

A further object of the invention is to provide, in a circuit breaker of the above character,- an improved contact member by means of which maximum area of contact between the relatively movable contact members may be preserved during the circuit making and breaking operations.

This application is a continuation in part of my application, Serial No. 702,153, filed December 13, .1933, allowed December 19, 1934, for Circuit breakers.

The invention is shown as embodied in the structure depicted in the drawings, and will be hereinafter more fully described in the light of an embodiment, and finally pointed out in the claims.

In the accompanying drawings,-

Figure 1 is a side view of the more important elements of the embodiment shown in the later views, certain operative elements being omitted for the sake of clarity; v

Figure 2 is a plan view taken on the line 2-2 of Figure 3;

Figure 3 is a sectional view partly in side elevation taken on the line 3--3 of Figure 2, and showing the parts in unlocked position, and with the circuit broken;

Figure 4 is a similar view showing the parts in locked position and the circuit closed;

Figure 5 is a similar view showing the parts in position whereby to be operated by manual means;

Figure 6 is a side view partly in section taken on the line 6-6 of Figure 4;

Figure 'I is a sectional view of a modified form of the invention, being taken on line 1-1 of Figure 8, in which the switch rod has a collar engaging the locking plate, and the thermostatic control is placed beneath the plate;

Figure 8 is a plan view of the same, taken on line 8-8 of Figure 7 Figure 9 is a plan view of the contact spring;

Figure 10 is a sectional view of another embodiment in which the thermostatic control acts to hold the switch rod, taken on line. lfl--l|l of Figure 11;

Figure 11 is a'pla'n view of the same, taken on line ll-H of Figure 12; A

'Figure 12 is a sectional view of another embodiment'in which the thermostatic control acts to hold the switch rod and also acts as a contact switch to the end of the switch rod;

Figure 13 is a sectional view of the same embodiment as shown in Figure 12, but taken at 5 right'angles thereto on line I3-I3 of Figure 12;

Figure 14 is a detail sectional view of the lower part of Figure 12, with the parts in a different position, just as current interruption is taking place;

Figure 15 is a sectional plan view taken on line I5--I5 of Figure 12;

Figure 16 is a sectional plan view taken on line l6-I6 of Figure 12; and

Figure 1'? is a plan view of the contact plate.

15 Referring to the details and more particularly to Figure 1, the usual threaded plug is indicated by III which has a contact member II at its lower portion and a spring member 32 connected with this lower contact piece II. These parts 20 are well known. To the screw-threaded plug I0 is secured a plate I I and this is seated within a casing I2, having a sleeve guide I3 through which a button I4 is adapted to pass. This button I4 is movable by the pressure of a hand into the casing I2 and may be held therein. When such holding is released, the button II under the action of a spring again moves outwardly of the casing along sleeve I3. The button I4 has a cylindrical portion I9 and this passes through 30 a circular opening I9 of the plate I5, which is held to the circular plate I! by means of screws I6. This plate is normally in inclined position in respect to the plate I! and may be pressed downwardly into a position substantially parallel with the plate I1, and when in this approximate position, the cylindrical member I9 may freely pass into andout of the circular opening l8 of the plate I5. When, however, the plate I5 takes an angular position with respect to the cylindrical member I9, then the inner edge of the plate I 5, which edge is formed by the circular opening I9, and particularly the uppermost portion at one side of the circular opening and at the lowermost portion of the opening at the side opposite to the uppermost portion, the part indicated by the leading line in Figures 3 and 4 of the reference character I9, engages with the peripheral portion of the cylindrical member I9, and locks the cylindrical member I9, and in consequence, the button I4, in a position within the casing I2. When the button I4 is pressed inwardly as far as it will go, as shown in Figure 1, the contact piece 3| will make contact with the contact piece 32 and hence the member II is in circuit therewith.

In order to operate the plate I5 from the exterior of the casing I2, the upper surface of the casing I2 is provided with a plunger member having a base portion 20 which engages, by

means of screw threads, a screw threaded recess in the top surface of the casing I2. This member 20 has a central bore, and therein is arranged a spring-controlled piston member 22, suitably spring actuated, so as to cause the plunger member 22 to return to its initial position.

When the plunger member 22 is pressed downwardly, as shown in Figure 5, by the finger, plunger 22 engages the plate I5 and presses the plate [5 downwardly, and thereby disengages the edge of the plate I5 from the cylindrical portion I9; thereby the button I4 under the actuation of the spring 35 is forced upwardly or out of the casing I2, as shown in the position of Figure 5.

, This'same release action may also be obtained by means of a thermostatic device. This therpushed down.

mostatic device consists of an upright member or post 23. To this post there is attached a horseshoe-like bi-metallic member of suitable current resisting qualities having its free end 25 closely approaching the plate I5, when the plate I5 is in locked position, as shown in Figure 4. An insulating plate I5 is provided on the end of plate I5 to prevent electrical connection between the element 24 and plate I5. When the amount of current passing through the plug exceeds the amount regulated by the specific material of which this horseshoe member is composed, an expansion takes place and the free leg 25 of the horseshoe member 24 moves downwardly and against the plate I5 and thereby moves the plate I5 downwardly and disengages its edge from the cylindrical member I9. The electrical circuit in which this horseshoe member 24 is inserted is shown by the wire 39 which has one end connected at 25 with the member 24 and the other end connected to the exterior metallic conductor of which the screw-threaded portion I0 is one part. The completed circuit includes shell ID as one terminal to which wire 39 is connected, bimetal element 24 to which the other end of wire 39 is connected, post 23, plate I'l, shaft 30, contact piece 3|, spring member 32, and contact member II. In consequence, when the amount of current exceeds a certain predetermined amount, the thermostatic device becomes actuated and moves the plate I5 in case the plate I5 is in locked position, and then moves it from the locked position to the unlocked position, and disengages the plate I5 from the portion I9, thereby moving the button I4 upwardly, breaking the contact between iii and 32.

' It will be seen that this contact is thereby broken by the thermostatic means, or in such cases where it is desirable, may be broken by the manual means by actuating the piston plunger 22.

My device forms a very convenient and simple mechanism which may be readily inserted in a standard cut-out. It is always ready for actuation, no part burning out, requiring the looking for spare parts, as it is self contained and always operative after beinginserted. Merely by pressing the button I4 downwardly, an engagement of the peripheral part of the member I9 with the edge of I 9 of the plate I5 takes place and holds the part I9 in position, and thereby the button in its inward position, corresponding to the closing of the circuit.

The size and dimensions of the circuit breaker are such that can be used in the existing cutouts, in place of fuses, without any alteration in the present installations. These circuit breakers can be made in all sizes, from flve to thirty amperes the same as well-known fuses, without any change in mechanism, with the exception that in the larger amperage, a thermostat is made more resistantand can readily be arranged in accordance with the amperage desired. The simplicity of the circuit breaker enables it to be marketed at a nominal figure. It consists of a round brass disc through which a plunger projects. To the upper end of the plunger, a push button is fastened. To the lower end of the plunger, a brass disc is fastened. This brass disc makes contact with the contact spring 32 in the lower part of the casing, when the plunger I9 is The plunger is pushed through an opening in a plate steel spring I5, which is bent at an angle to the round disc I I on which it is supported. When the plunger is pushed down, it bends the spring plate I5 downwardly and allows the plunger to pass through the hole of the plate spring without hindrance, but as soon as the finger is released from the push button l4, the plate spring or platform comes back in its original position, which is at an angle to the brass disc H, and thereby arrests the plunger l9 so it stays in the position it has been placed.

The thermostat acts inv a neutral manner when normal current passes through; and then remains in its original position. When excessive current passesthrough the thermostat, the thermostat opens up until it presses on the plate spring or platform, and it eventually depresses the plate spring or platform sufllciently to allow the plunger to pass through the hole and thereby it disconnects contact between the spring and the brass disc in the bottom of the circuit breaker providing an arc gap of about {a of an inch. The coil spring 35 around the plunger 30 returns the plunger very quickly, thereby minimizing arcing.

It will be seen that the construction of the thermostat is so arranged that in case there is an overload of about 25% over the rated amperage of the circuit breaker, it gives the overload about five to ten minutes time to become normal,

and in case it should not return to normal, it de- 35 out giving the overload a chance to become normal, and thereby cause a great deal of trouble in present installations, as there are a good many small motors now in use which have a greater starting torque than the normal rating. In the circuit breaker described, however, the parts are so arranged and the action is such that a small overload does not actuate the circuit breaker and allows a short time to pass before it actuates, and then actuates only in case of an actual over amperage of more or less permanent relation. Thus, the improved circuit breaker herein described overcomes the objections of the old fuses, as an arrangement has been made for a time-lag of an overload and an immediate disconnection on a short circuit. The small button or piston plunger 22 hereinbefore described disengages the spring platform I5 mechanically whenever it should become necessary to open the circuit without removing the circuit breaker from the cutout.

The spring 35 surrounds the sub-calibre stem 3|! of the part IS, the spring 35 acting against the shoulder of the part I9 at one end, and against an inwardly disposed portion 31 of an extension 35 of the disc plate ll. This construction is very simple to make and lends itself readily to assembling.

' It will be noted that the space between the spring plate and the lower end of the thermostat U shaped member is very small, when these parts are not in contact, that is, when the device is in unlocked position, and this is an important feature of this invention. Hence, when the spring plate is in locked position, the space between it and the lower leg of the U adjacent thereto is closed so that a very small movement of the leg will move the spring plate, and it requires a very small movement of the spring plate to disengage itself fromthe plunger at the same time.

In Figures '1 and 8, another embodiment is shown, in which the switch rod 50 has a. collar 5|, adapted to engage an insulating ring 52 of a plate 53 held by screws 54 to the base 55. A helical spring 56 is interposed between the collar 5| and a cup-like member 54, this spring 55 passing through the interior bore of the ring 52. The plate is limited in its movement by the adjustable nut 58 on a screw-threaded stud 59 secured to the base 55. A release pin 60 may be pressed against the plate 53 to release it. To the lower side of the plate the thermostatic control is placed, which is in the form of a plate 6|, secured at 62 to the plate 53 and resting at its free end upon an extension 53 of the cuplike member 64, in which the spring 55 is seated. The thermostatic control plate 5| is of general horseshoe shape and is secured to base plate 63 by means of rivets 6|". Base 531s insulated from base 55 by means of insulation 63' and the other end of plate 6| is provided with a slot 6| which is slidably received beneath the lower head of rivet 62. The lower end of the switch rod 50, through its enlargement 51, contacts with the serpentine spring contact 65, secured to the exterior contact 66, and when in contact the circuit is closed. An excess current will actuate the thermostatic control and this will remove the spring-like action of the same, which serves to cause the plate 53 to lock the switch rod 50, and thereby on the plate 53 descending an unlocking will take place and the switch rod will break contact with the contact 65. The path of current through the device shown in Figures 7 and 8 is traced from the shell H and base 55 connected thereto by means of a wire 55' through the plate 53, bi-metal element 5|, base 63 which is insulated from base 55, rod 50, contact member 5|,and contact 65 to terminal 65.

It will thus be seen that, in the construction shown in Figures 1 through 8, a jamming action takes place between the movable member and the bi-metal element or device controlled thereby.

In another embodiment shown in Figures 10 and 11, the thermostatic control serves an additional function. In this embodiment, the control acts at the same time as a locking member for the switch rod which is slidably received in a guide 54'. The switch rod 50 has an insulating collar 5|, and a contact portion 51. The control is in the form of a collar 10 surrounding the collar 5| of the switch-rod 50. 'This control collar i is composed of two different thermo metals and has one end secured to the fixed abutment 12, secured to the base 13, and has the other and free end 74, normally supported on a wiper i5. The control collar I0 is so arranged that it provides a frictional hold on the collar of the switch rod 50, when the switch rod collar 5| is engaged by the control collar 10. When, however, an excess of current passes through the device, the collar 70 opens and permits the switch rod collar 5| to be released. Manual release of the switch rod can also take place. This is accomplished by a vertically movable pin 75 passing to the exterior of the casing Ti, and guided by an opening 18 in the guide 54. When the pin 16 is pressed downwardly it moves the free end 14 of the control collar and opens it, whereby the switch rod under the action of the spring 19 is released. The path of current through the device shown in Figures 10 and 11 extends from the shell H to the bracket 12 which is electrically connected thereto, thermal element 10, contact 15, plate 63, shaft 50, contact member 51, and breaker terminal not illustrated but corresponding to the central terminal in the device shown in Figure 7.

In Figures 12 to 17, still another embodiment is shown. The control collar now performs still an additional function, namely, it acts as a contact member. The switch rod 5t! has at its lowermost end the collar 5| beneath which is supported rod 5|) upon which is provided a collar 5l The thermostatic control is now electrically connected with the contact 66. The control consists of two like parts, having ends 88 joined together, by an adjustable screw 8|, and then provided with curved portions 82, terminating in free ends 83. The curved portions 82 are so shaped as to embrace the collar 5| in hugging manner so as to frictionally hold the same when it is placed therebetween. When the collar Sl is forced between the curved portions 82, it is held therebetween. If the current exceeds the normal or predetermined amount, the thermostatic action takes place, and the collar 5| is released and the switch rod can under the action of a spring, as has been described in connection with the other embodiments, ascend. Manual release can be had by means of the insulated wedge 84 interposed between the free ends 83. A high resistance shunt post 85, in electrical connection with the plate 66 cooperates with a rod 86 secured to the switch rod 50, whereby the final current flow passing through post 85 and rod 86 can be interrupted. so that no arcing of any kind takes place at the thermostatic control, which in this embodiment acts also as a locking device and as a contact device. The path of current through the device shown in Figures 12 through 17 includes shell ll, connections 95, plate 63. shaft 59', collar 5", thermal elements 82, and bottom terminal v66.

In the embodiment of Figures 12 to 17, it will be particularly noted that while the thermostatic control engages the plunger, it acts as a spring plate. In other words. the control is essentially a spring plate to lock or clutch the plunger, and thecontrol acts on this spring plate to release the plunger. The direct action of spring plate and control upon the plunger of an electric light socket plug member, whether the spring plate is mechanically separate from the control, or is mechanically a part of the control, constitutes the novelty of this invention.

The embodiment of Figures 12 to 17 has certain mechanical features. For instance, the

switch rod consists of two parts, the upper part 58, operated by the push button 90, which when pressed moves the rod 50 downwardly. The lower end of rod 5!) is screw-threaded into the collar 5|, into the lower end of which the screwthreaded upper end of the rod 50, is secured. Upon the collar 5| is placed the bent end 9| of the rod 86, and this is held down by the screwthreaded washer 92 against the collar 5|. The rod 50 passes through a cup-shaped portion 64 of the plate 63, which plate 63 has an opening 93 for the free passage of the rod 86. The plate 63 isnow bent downwards to form screw threads in the form of two diametrically opposed bars 95. Spaces 96 are left open to form vent holes for any gases. To the lower part of the plate 63 is secured a downwardly depending guide piece 91, upon which the rod 86 slides, and the contact therebetween assists in the current flow. A plate 66 is held in position by the upset part. 98 of the contact member 66, and this plate has recesses 99 engaged by tongues I09 of the control. I

The plate 66 seats against a shoulder H.

In Figure 14, the rod 59 is ascending as shown by the arrow I02, and the contact between the collar 5| and control 82, is broken. Current however is still on throughthe post 85 and rod 86, and when these parts separate the current is entirely interrupted.

In order to manually break contact, the insulated wedge member 84 is pressed by the elbow lever I03 into the space between the free ends 83 of the control and these being separated, remove their frictional contact with the collar Bi and release it, to enable it to act under the action of the spring 56. The elbow lever I03 pivoted at I06 may be actuated by the push button I94. Ears "15 are punched out from the plate 63 to act as trunnions for the pivot pin I06.

I have described various embodiments of my invention, but I do not desire to be limited to the details thereof, as changes may be made therein without departing from the spirit and scope of my invention as set forth in the appended claims.

I claim:

1. A circuit breaker comprising an electric light socket plug member, a plunger in said member, a spring for acting on said plunger, a spring plate for acting directly on said plunger for holding the same in locked position, and a thermostatic member in circuit with said socket adapted to act on said spring plate when said spring plate engages the plunger, and closes the circuit, and electric connections for conducting electric current through the thermostatic member, whereby when an excess of current passes through the thermostatic member, the plunger and spring plate are disengaged and the electric circuit is broken.

2. A circuit breaker comprising an electric light socket plug member, a plunger in said member, a spring for acting on said plunger, a plate having an opening larger than the circumference of the plunger to receive the plunger, means to mount said plate at an angle to the axis of the plunger, a thermostatic member in circuit with said socket, having an end movable and disposed in operative relation to said plate, and electric connections for conducting electric current through the thermostatic member, whereby when an excess of current passes therethrough, the member moves the plate and disengages the plate from the plunger and breaks the electric circuit.

3. A circuit breaker comprising an electric light socket plug member, a plunger in said member, a spring for acting on said plunger, a plate having an opening larger than the circumference of the plunger to receive the plunger, means to mount said plate at an angle to the axis of the plunger, a thermostatic member in'circuit with said socket, having an end movable and disposed in operative relation to said plate, electric connections for conducting electric current through the thermostatic member, whereby when an excess of current passes therethrough, the member moves the plate and disengages the plate from the plunger and breaks the electric circuit, and a manual spring operated piston member in the path of the plate for moving the plate and disengaging it from the plunger.

4. In combination, a stationary contact, a 'reciprocating plunger, a movable contact on the plunger, a spring urging the plunger into an open position and a plate of metal normally in an obliquely inclined plunger holding position in respect to the axis of the plunger, electric connections connecting the plate in circuit with the contacts, release means engaging the plate laterally of the plunger, said plate being adapted to be pressed in one direction by the plunger, and upon the opposite movement of the plunger returning to its normal position and engaging the plunger to hold the plunger in locked position.

5. A circuit breaker comprising a socket plug having a screw threaded shell, a contact piece insulated from said shell and supported by said plug, a casing for said shell and contact piece, a plunger having a button extending outside of the casing, and a sub-calibre stem inside of the casing, a spring surrounding said sub-calibre stem and abutting the plunger, a disc having a cup for supporting the other end of the spring, a plate pivoted to saidcup disc for engaging the plunger, a thermostatic conductor for engaging said plate, and a spring actuated piston rod supported on the casing and extending exteriorly thereto for engaging said plate, whereby when the current exceeds a certain predetermined amount, the conductor moves the plate to disengage it from the plunger, and break the circuit, or the plate may be moved manually by the piston rod to break the circuit.

6. A circuit breaker comprising an electric light socket plug member, a spring actuated plunger in said member, a thermostatic control spring plate acting directly on said plunger when in contact therewith and surrounding the plunger, the thermostatic control spring plate being in circuit with said member movable by the action of an excess current to release the connection between the plunger and plate, and electric connections for conducting electric current through the plate, whereby when an excess of current passes through the plate, the plate is moved, the plunger is disengaged, and the circuit is broken.

7. A circuit breaker comprising an electric light socket plug member, a spring actuated plunger in said member, a thermostatic control spring plate acting directly on said plunger when in contact therewith and surrounding the lowermost end of the plunger and acting as a contact device, the thermostatic control spring plate being in circuit with said member movable by the action of an excess current to release the connection between the plunger and plate, and electric connections for conducting electric current through the plate, whereby when an excess of current passes through the plate, the plate is moved, and the plunger is disengaged, and the circuit is broken.

8. A circuit breaker comprising an electric light socket plug member, a spring actuated plunger in said member, a thermostatic control spring plate acting directly on said plunger when in contact therewith and surrounding the lowermost end of the plunger and acting as a contact device, a shunt stud in contact with the plate, a shunt rod on the plunger in contactwith the shunt stud, the plunger discontinuing contact with the plate, before contact between the shunt stud and shunt rod is discontinued, the thermo- 9. A circuit breaker comprising an electric light socket plug member, a spring actuated plunger in said member, a thermostatic control spring plate acting directly on said plunger when in contact therewith and surrounding the lowermost end of the plunger and acting as a contact device, a shunt stud in contact with the plate, a shunt rod on the plunger in contact with the shunt stud, the plunger discontinuing contact with the plate before contact between the shunt stud and shunt rod is discontinued, an exterior release means including an exterior push button elbow lever and wedge, to operate the plate, to release it from the plunger, the thermostatic control spring plate being in circuit with said member movable by the action of an excess current to release the connection between the plunger and plate, and electric connections for-conducting electric current through the plate, whereby when an excess of current passes through the plate, the plate is moved, the plunger is disengaged, and the circuit is broken.

10. Means for breaking an electric circuit comprising a spring actuatedelement, a terminal adapted to be engaged by the element said terminal including thermostatic mechanism adapted to hold the element against the action of the spring, and electric connections for conducting electric current through the thermostatic mechanism and terminal, whereby when an excess of current passes through the member the element is released and the circuit broken.

11. Means for breaking an electric circuit comprising a spring actuated element, a terminal adapted to be engaged by the element, thermostatic mechanism on the terminal adapted to hold the element against the action of the spring, shunt connections on the terminal and element, and electric connections for conducting electric current through the thermostatic mechanism and terminal, whereby when an excess of current passes through the member the element is released andthe circuit broken said shunt connections being formed to be disconnected after the element and terminal are disconnected.

12. A circuit breaker comprising a supporting member, a spring actuated element in said member, a thermostatic member adapted to engage and hold the element frictionally with a hugging action against the action of the spring, and electric connections for conducting electric current through the thermostatic member, whereby when an excess of current passes through the member the element is released and the circuit broken.

13. A circuit breaker comprising a supporting member, a spring actuated element in said member, a thermostatically operated clutch mechanism movable by the action of an excess current to release the element, electric connections for conducting electric current through the thermostatic mechanism, whereby when an excess of current passes through the mechanism, the element is released and the circuit broken, shunt contacts across the circuit, and means to break the last named contacts subsequent to the breaking of the circuit by the element.

14. A circuit breaker comprising a supporting member, a spring actuated element in said member, a thermostatically operated clutch mechanism movable by the action of an excesscurrent to release the element, electric connections for conducting electric current through the thermostatic mechanism, whereby when an excess of current passes through the mechanism, the element is released and the circuit broken, and

, means to adjust the clutch mechanism.

15. A circuit breaker comprising a supporting member, a. spring actuated element in said member, a thermostatically operated clutch mechanism secured to the member and having a free end, the mechanism being formed to exert a wrapping frictional engagement with the element and movable by the action of an excess current to release the element, and electric connections for conducting electric current through the thermostatic mechanism, whereby when an excess of current passes through thecontrol the element is released and the circuit broken.

16. A circuit breaker comprising a supporting member, a spring actuated element in said member, a thermostatically operated clutch mechanism movable by the action of an excess current to release the element, electric connections for conducting electric current through the thermostatic mechanism, whereby when an excess of current passes through the mechanism, the element is released and the circuit broken, manually operable means for disengaging the element, shunt contacts across the circuit, and means to break the last named contacts subsequent to the breaking of the circuit by the element.

17. A circuit breaker comprising a supportin member, a spring actuated element in said member, a thermostatically operated clutch mechanism secured to the member and having a free end, the control being formed to exert a wrapping frictional engagement from the element and movable by the action of an excess current to release the element, a wiping contact member on the mechanism, and electric connections for conducting electric current through the thermostatic control, whereby when an excess of current passes through the control, the element is released and the circuit broken.

LAMBERT SCHMIDT.

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