US2228466A

US2228466A - Circuit breaker

Info

Publication number: US2228466A
Application number: US168204A
Authority: US
Inventors: Leon R Ludwig; Lindstrom Ture
Original assignee: Westinghouse Electric and Manufacturing Co
Current assignee: CBS Corp
Priority date: 1937-10-09
Filing date: 1937-10-09
Publication date: 1941-01-14
Anticipated expiration: 1958-01-14

Description

Jan. 14, 1941. L. R. LUDWIG ETAL CIRCUIT BREAKER Filed Oct. 9, 1937 3 Sheets-Sheet l 5 R O N E v m Jan. 14, 1941- L. R. LUDWIG ETAL CIRCUIT BREAKER Filed Oct. 9, 1937 s Sheets-Sheet 2 WITNESSES: g w

Jan. 14, 1941. LUDWlG ETAL 2,228,466

0 I RCUI 'I' BREAKER Filed Oct. 9, 1937 5 Sheets-Sheet 3 Patented Jan. 14, 1941 UNITED STATES PATENT OFFICE CIRCUIT BREAKER Application October 9, 1937, Serial No. 168,204

23 Claims. The invention relates to circuit breakers, and

more particularly, to operating means therefor. I

In a large number of applications of circuit breakers, it is desirable to provide the, breaker with a motor-driven operating mechanism for opening, closing, or resetting the breaker, and which may be set in operation from a remote point and which also permits manual operation of the breaker. A mechanism of this type is disclosed in the copending application of Ture Lindstrom, Serial No. 59,387, filed January 16, 1936, and assigned to the assignee of this invention, which application became Patent No. 2,192,046 on February 27, 1940. The mechanism there disclosed'comprises, in general, a motordriven crank for oscillating a connecting rod which is releasably connected to the operating handle of the breaker by a handle attachment.

The handle attachment is such that when a go handle member is inserted, it automatically effects disconnection of the breaker handle from the connecting rod to permit manual operation of the breaker by the handle member. A resilient link is interposed between the crank and the 2; connecting rod for permitting the necessary overthrow of the crank relative to the breaker handle to enable the mechanism to reset the breaker.

While the above-described mechanism is satis- 30 factory in many respects, it possesses certain disadvantages. The mechanism requires extremely accurate design and adjustment of the various parts to provide satisfactory operation and is relatively expensive to manufacture. Fur- 5 thermore, the arrangement does not insure against breakage of the operating handle if too great a load is imposed thereon by the mechanism. The present invention constitutes an improvement over the above-mentioned structure 40 and obviatesthe objectionable features thereof.

It is an object of the present invention to provide an improved motor operating mechanism for circuit breakers, which is simple, safe and reliable in operation and inexpensive to manu- 45 facture.

Another object of the invention is the provision of an improved motor-operating mechanism which, after being initially set in operation, is automatic to effect either opening, closing or 50 resetting of the breaker, and which readily permits manual operation of the breaker when desired.

Another object of the invention is the provision of an improved motor-driven oscillating mecha- 55 nism for operating a circuit breaker, embodying (Cl. 200-922) F a novel clutch means which serves to normally connect the breaker operating member to the mechanism for movement thereby and which permits necessary overtravel of the mechanism relative to the breaker operating member.

Another object of the invention is the provision of an operating mechanism as described in the preceding paragraph, in which the clutch means is operable to automatically release the breaker operating member from the mechanism when m the load imposed on the member by the mechanism exceeds a predetermined safe maximum value, and which is also operable by a manually operated handle to release the breaker operating member from the mechanism to permit manual 15 operation of the breaker by the manually operated handle.

The novel features that are considered characteristic of the invention are set forth in particular in the appended claims. The invention itself, however, both as to structure and operation, together with additional objects and advantages thereof, will best be understood from the following detailed description of a preferred embodiment thereof, when read in connection with the accompanying drawings, in which:

Figure 1 is a side elevational view, partly in section, of a circuit breaker embodying the motor operating mechanism of the invention;

Fig. 2 is a plan view of the circuit breaker and its motor operating mechanism shown in Fig 1;

the emergency handle being removed from the handle attachment;

Fig. 3 is an enlarged fragmentary end view,

partly in section, of the handle attachment of the motor operating mechanism;

Fig. 4 is a side elevational view of the handle attachment shown in Fig, 3;

Fig. 5 is an end elevational view of an operat- 7 ing lever which forms a part of the handle 40 attachment shown in Figs. 3 and 4 Fig. 6 is--a side elevational view of the operating lever shown in Fig. 5:

Fig. 7 is an end elevational view of the rocking lever which forms a part of the handle attachment shown in Figs. 3 and 4;

Fig. 8 is a side elevational view of the rocking lever shown in Fig. 'I;

- FigQ Q is an end elevational view, partly in section, of the motor unit and crank driven thereby; I

Fig. 10 is a side elevational view, partly in section, of the motor unit; and Q Fig. 11 is a fragmentary end elevational view of the motor unit with the end cover removed to motor.

Referring to the drawings, the circuit breaker illustrated generally at H is o! the three-polesnap-action type of the same general construction as the circuit breaker shown and described in Patent 1,918,232, issued to B. P, Baker and M. W. Brainard, July 11, 1932,'and assigned to the assignee of this invention. or structure and operation of this type of circuit breaker are set forth completely in the aforementioned patent, only so much of the circuit breaker structure is here shown and described as is considered necessary for a complete understanding of the present invention.

Referring to Fig. 1, the circuit breaker illustrated comprises a base l3 and a cooperating cover 5, both of molded insulating material, a stationary contact means H, a cooperating movable contact means i9, actuating means for the contact means indicated generally at 2 I, a manual operating handle 23 of molded insulating material, and a tripping mechanism indicated generally at 25. The section illustrated in Fig. 1 is taken substantially through the center pole of the breaker in order to illustrate the common actuating means for the contacts of the breaker. The center movable contact I! is carried by a switch arm 21 which is pivoted to a U-shaped frame 29 by means of a pivot pin 3|. The switch arms and movable contacts carried thereby for the other two poles of the breaker are secured for simultaneous movement with the central switch arm 21 by means of an insulating tie bar 33, which extends across all three poles of the circuit breaker.

The common actuating mechanism 2| which is disposed in the center pole space of the breaker comprises a pair of toggle links 35 and 31, a releasable support 39 for the upper end of the toggle and over-center spring means 4|, which connect the knee of the toggle with the upper end of a U-shaped operating member 43. The lower toggle link 35 is pivoted at its lower end to the switch arm 21 while the upper toggle link is pivotally connected at its upper end to the releasable support 39.

The releasable support 39 is pivoted on the main frame by means of a pivot pin 45. The right-hand end of the releasable Support 39 is normally held in latched position by means of a latching member 41 of the tripping means 25 to maintain the toggle in operative position. The U-shaped operating member 43 is pivotally mounted at its lower end to the sides 01' the main frame 28 and has the operating handle 23 secured to its upper end. A knob portion of the operating handle 23 projects through an opening 49 provided therefor in the cover IS. The tripping mechanism 25 may be of the type more fully described in Patent 2,047,739, issued to H. J. Lingal, July 14, 1936, and assigned to the assignee of this invention.

The operation of the circuit breaker as thus far described is briefly as follows. To open the contact means of the circuit breaker the operating handle 23 is moved in a clockwise direction. The clockwise movement of the operating handle 23 moves the line of action 01' the overcenter springs 4| to the right, and as the line of action of the springs crosses the pivotal connection between the upper toggle link 31 and the releasable support 39, the force exerted by the springs 4| causes the toggle links to collapse and Since the details.

thereby move the switch arm 21 to the open circuit poution with a snap action.

To close the breaker, the operating handle is moved in a counter-clockwise direction, and substantially the reverse action takes place. The movement of the operating handle 23 in a counter-clockwise direction moves the line oi action of the over-center springs 4|, and when their line of action crosses the pivotal connection of the link 31 with the releasable support 55, the force exerted by the springs causes the toggle links to be moved to their overset position, as shown in Fig. 1, thereby moving the switch arm 21 to the closed circuit position with a snap action.

When an' overload occurs in the circuit of any one of the poles of the breaker, the tripping mechanism 25 causes the latching member 41 to release the right-hand end of the pivoted support 35, thus allowing the support 39 to be moved upwardly under the influence of the overcenter springs 4|. This'upward movement of the releasable suppo t elIects collapse of the toggle links 35 and 31 and movement of the switch arm 21 to the open circuit position.

Before the breaker can be reclosed following a tripping operation, it is necessary to reset the actuating mechanism. In order to reset the actuating mechanism the operating member 43 is provided with a depending projection 5| for engaging the releasable support 39, To reset the breaker, the operating handle 23 is moved in a clockwise direction to cause the projection 5| to engage and move the releasable support 39 to its latched position shown in Fig. 1. The operating handle is moved slightly beyond the normal open position in order to effect resetting of the releasable support 39, in engagement with the latching member 41.

The motor operating mechanism for the circuit breaker is indicated generally at 53 and comprises in general a motor unit 55 for driving a rotatable crank arm 51, and a handle attachment 58 mounted on the breaker operating handle 23, and having a part connected to the crank arm 51 for oscillation thereby. The handle attachment 58 includes a clutch means for releasably connecting the breaker handle 23 with the motor-driven part of the handle attachment, as will be described hereinafter.

The motor operating mechanism 53 is secured to a frame 6| by means of a plurality of bolts 52 (Fig, 2), the frame 6|, in turn, being secured to the breaker base I! by means of a plurality of bolts 65. The frame 5| is generally rectangular in shape and includes a pair of angular brackets 51 for mounting on the bolts which pass through the breaker base I3, the cover I5, and through suitable openings provided therefor in the brackets 51.

The motor unit 55 comprises'a suitable casing 65 (Figs. 9. and 10) within which is mounted a driving motor 1| of the universal type. A gear casing 13 is secured to one end of the casing 59 and an extension of the armature shaft of the motor 1| projects into the gear casing 13. Upon this extension is mounted a worm 15 which engages a worm gear 11. The worm gear 11 is secured for rotation with a counter-shaft 19 rotatably mounted in suitable bearings within the gear housing 13. One end of the counter-shaft 15 extends through a side of the gear casing 13 and has rigidly mounted thereon a crank arm 51. The end of the crank arm 51 is provided with a suitable crank roller 53 which is adapted to engage a slot provided therefor in a rocking lever which forms a part of the handle attachment 53. The worm and the worm gear 11 provide a simple and inexpensive reduction gear between the crank arm 51 and the motor 1I, so that the crank arm is driven at a considerably reduced speed compared to the speed of the motor 1|.

The handle attachment 50 serves to connect the crank arm 51 with the breaker operating handle 23, and comprises, in general, an operating lever 05, a rocking lever 91, and a clutch means indicated generally at 39 for releasably connecting the operating lever 35 to the rocking lever 31 for movement thereby. The operating lever 05 (Figs. 5 and 6) consists of an integral casting and is provided at its lower end with a yoke 9| for attaching the operating lever to the breaker operating handle 23. The yoke 9| has a pair of spaced lugs 93 shaped and spaced apart so as to snugly engage the knob portion of the breaker operating handle 23. The lugs 93 are provided with aligned threaded openings for receiving a pair of fastening screws 95 which are adapted to pass through suitable openings provided therefor in the breaker operating handle 23. The screws 95 serve to securely fasten the yoke 9| of the operating lever 95 to the breaker operating handle 23.

A pair of bearing brackets 91 are secured to the opposite sides of the yoke portion 9| of the operating lever 85, the brackets 91 being secured to the opposite ends of the lugs 93 of the yoke 9I by means of fastening screws 99. The bearing brackets 91 serve to pivotally support the rocking lever 91. Adjacent its mid-portion the lever 85 is provided with an integral bracket projection IOI. A portion I03 of the bracket IOI extends opposite and parallel to the body portion of the lever 85. The central portion of the lever 05 adjacent the bracket IN and the parallel portion I03 of the bracket IOI are provided with vertical guide slots I05 which serve to slidably support and guide a roller which forms part of the clutch means to be hereinafter described. The upper end of the lever 85 has a horizontal portion I 01 extending at right angles thereto and this portion is provided with a circular opening I 09 for a purpose to be hereinafter described.

The rocking lever 81 (Figs. '7 and 8) consists of an integral casting provided with a vertical slot III for receiving the crank roller 03 carried by the crank arm 51. The lower end of the rocklng lever 91 is provided with a pair of spaced bearing legs II3 adapted to fit within the bifurcated portions of the bearing brackets 91 as best shown in Fig. 3. The bearing legs II3 of the rocking lever 81 are secured for pivotal movement in the bearing brackets 91 by means of pivot pins II5 which engage openings H1 and H9 provided therefor in the bearing legs H3 and the bearing brackets 91. The lever 81 is also provided with a horizontal shelf portion I2I which is off-set from the body portion of the lever. Theshelf portion I2I has an arcuate recess I23 formed therein which is adapted to receive the clutch roller I25 carried by the operating lever 95. The rocking lever 91 is adapted to be oscillated by the rotation of the crank arm 51 when the motor H is rotated, and the operating lever 95 is normally connected for movement with the rocking lever 01 by means of a releasable clutch device.

The clutch device (Figs. 3 and 4) for releasably coupling the operating lever 05 to the rocking lever. 81 comprises a spring pressedroller I25 carried by the operating lever 05, for engaging the arcuate roller receiving recess I23 formed in the shelf portion I2I of the rocking lever 91, The roller I25 is rotatably carried by a roller shaft I21 the ends of which are in slidable en- Bagement with the vertical guide slots I05 of the operating lever 95.

A cylindrical roller carrying member I29 has its upper end slidably received in the circular opening I09 of the portion I01 of the lever 35. The lower end of the roller carrying member I29 has a bifurcated member I3I secured thereto. The legs of the bifurcated member I3I are provided with a pair of aligned openings I33 for engaging the roller shaft I21 on opposite sides of the roller I25. The roller I25 is biased in a downward direction by means of a compression spring I35 which encircles the roller carrying member I29. The upper end of the spring I35 engages the portion I01 of the lever 95 while the lower end of the spring engages the bifurcated member I3I. The spring I35 serves to normally maintain the roller I25 firmly seated in the roller receiving arcuate recess I23 of the rocking lever The roller carrying member I29 is provided with a vertical threaded opening I31 for receiving the lower end of an emergency operating handle I39. The emergency operating handle I39 is provided with a reduced portion IlI forming an annular shoulder 3 which engages the upper surface of the portion I01 of the lever 05. The emergency handle I39 is also provided with an annular recess 5 between the reduced portion IlI thereof and the annular shoulder I l3.

The annular recess 5 permits upward movement of the roller carrying member I29, being of suflicient width to receive the upper end of the said roller carrying member. The threads of the reduced portion IlI engage the internal threads of the roller carrying member I29, so that when the emergency operating handle I39 is turned in a clockwise direction the roller carrying member I29 is moved upwardly to withdraw the roller I25 from the arcuate recess I23 of the rocking lever 31. This effects release of the operating lever 85 from its connection with the rocking lever 01 so as to permit manual operation of the breaker by means of the emergency handle I39. The edges of the arcuate roller receiving recess I23 are rounded as indicated at I" (Fig. 8) and terminate in the sloping sides 9 of the horizontal shelf I2I. The rounded edges 1 permit the roller I25 to roll out of the recess under certain conditions, and the sloping sides 9 permit the roller to roll back into the recess to reset the clutch mechanism following its release.

The'motor II is provided with a suitable control circuit for energizing the same to effect opening, closing or resetting of the breaker. One form of control circuit for the motor is disclosed in the aforementioned copending application of Ture A. Lindstrom, Serial N 0. 59,387. The control circuit of the motor includes suitable opening and closing switches for controlling opening or closing of the breaker, and a suitable limit switch operable to open the motor circuit immediately after the contacts of the breaker have been operated which occurs before the breaker handle reaches either end position due to the overcenter spring mechanism 2I of the breaker. The limit switch may be of the type disclosed in the aforementioned Lindstrom application and disposed within the gear casing 13 and the cover ISI for the gear casing.

In order to assist in bringing the motor to rest promptly at the end oi the stroke of the rocking lever 81, the motor is provided with a suitable brake mechanism, indicated generally at I53. The brake mechanism may be of a type similar to the brake mechanism disclosed in the aforementioned Lindstrom application, Serial No. 59,387. The brake mechanism comprises a brake shoe carrying arm I55 secured on the end of the motor shaft, which carries a pair of brake shoes I51 at its opposite ends. The brake shoes I51 are pivotally mounted on the ends of the arm I55 by means of pivot pins I55 and are biased by suitable spring means, not shown, in a clockwise direction about their pivot axes. The brake shoes I51 are adapted'to engage an internal braking surface Iii formed integral with the motor casing 55 when the motor speed increases during operation of the breaker actuating mechanism.

The operation of the motor operating mechanism for the breaker is briefly as follows. To open the circuit breaker the opening control switch of the motor control circuit is operated so to energize the motor. The rotation of the motor effects rotation of the crank arm 51 through 180 degrees at a reduced speed to cause clockwise movement of the rocking lever 31, as viewed in Fig. 1. Since the operating lever 35 is coupled to the rocking lever 31 by means of the roller I25 engaging in the arcuate recess I23, the operating lever 85 is also rotated in a clockwise direction with the rocking lever 81. The clockwise movement of the rocking lever 31 and the operating lever 85 moves the breaker operating handle I23 in a clockwise direction to eifect opening of the circuit breaker in the manner previously described.

As soon as the overcenter springs ll of the breaker actuating mechanism 2| have been moved overcenter to actuate the contacts of the breaker, the force required to complete opening movement of the breaker operating handle 23 becomes substantially decreased so that the driving motor 1| tends to speed up. The increased speed of the motor causes the brake shoes I51 to be moved outwardly by centrifugal force causing the brake mechanism I53 to retard rotation of the motor shaft. At substantially the same time, the limit switch of the motor is open, deenergizing the motor circuit. The brake mechanism I53 acts to retard the speed of the motor shaft so that the rocking lever 31 is brought to rest substantially at the completion of its stroke.

In closing the breaker, substantially the reverse action takes place. The closing control switch of the motor circuit is operated to energize the motor to cause it to rotate in the same direction. The rotation of the motor causes the crank arm 51 to be rotated through 180 degrees to eh'ect counter-clockwise rotation of the rocking lever 81 and since the operating lever 35 is coupled to the rocking lever by means of the spring pressed roller engaging the arcuate recess I23, the operating lever 35 is also rotated in a counter-clockwise direction. The operating lever 85 being connected to the breaker handle 23, moves that handle from the open position to the closed position to effect closing of the breaker contacts in the manner previously described. As soon as the overcenter springs of the breaker actuating mechanism 2| have been moved over center to actuate the contacts of the breaker, the motor speeds up and eifects operation of the closed position shown in Fig. 1, to hold the breaker operating handle 23 also in closed position. Since the breaker is of the trip-free type, the contacts are opened, in response to the overload irrespective of the position of the breaker operating handle. To reset the breaker, the opening 3 control switch of the motor circuit is operated to eii'ect energizing of the motor 1| and movement of the rocking lever 31 and the connected operating lever 35 to the reset position. The rocking lever 31 has a slightly greater stroke than the normal operating stroke of the breaker operating handle 23, in order to move the breaker operating handle 23 slightly beyond the normal open position to its rsetting position to eil'ect resetting of the breaker actuating mechanism following the tripp ng operation.

The rocking lever 31 has a slightly greater Stroke than the stroke of the operating handle 23 of the breaker. The overtravel of the rocking lever 31 relative to the operating lever 35 is permitted by reason of the specific clutch device including the roller I25 and the arcuate recess I23. During overtravel of the rocking lever 31 in either direction, the roller I25 rolls up either side of the arcuate recess I23 against the bias of the spring I35. This action of the roller during overtravel acts to effect stopping of the motor, whose speed has already been retarded by the brake mechanism, at the ends of the stroke of the rocking lever.

The clutch device comprising the roller I25 and the arcuate recess I23 of the rocking lever 31 positively prevents breakage of the operating handle 23 of the breaker. The slope of the sides of the arcuate recess 23 and the force exerted by the biasing spring I35 are such as to permit the roller I25 to roll out of the arcuate recess to effect release of the operating lever 85 from the rocking lever 31 whenever the load imposed on the breaker oprating handle 23 by the motor mechanism exceeds a predetermined maximum safe value. The force exerted by the spring I 35 normally maintains the roller I25 in engagement in the recess I23 to connect the lever 35 to rocking lever 31 for movement thereby. Thus, the clutch device normally couples the breaker operating handle 23 to the operation thereby and also operates automatically to release the breaker handle 23 from connection with the motor mechanism whenever the load imposed on the breaker handle 23 exceeds a predetermined safe value.

In certain instances, it may be desirable to manually operate the circuit breaker. To manually operate the circuit breaker, the emergency operating handle I33 is turned in a clockwise direction. The clockwise turning of the emergency handle I39 moves the roller I25 upwardly to disengage it from the recess I23 of the rocking lever 31. This eflects release of the operating lever 35 from its connection with the rocking lever 31. Under these conditions, the breaker may be manually operated by means or the emergency handle I33 in the manner previously motor mechanism iordescribed in connection with the manual operation of the breaker.

The sloping sides I49 of the shelf portion I2I of the rocking lever and the rounded ends I" of the roller receiving recess I28'permit the roller I to roll back into its normal position in the recess I23 to reestablish the connection between the levers 85 and 81 following either the automatic or manual release of the clutch mechanism. To reset the clutch mechanism 88 the motor circuit is energized and the lever 81 is moved. The inclined sides I88 of the lever 81 first push the'roller I25 and thelever 85 until the lever 85 reaches one of its limits of movement. Continued movement of the rocking lever 81 then causes the roller I25 to move upwardly along the incline I48 against its spring bias until it rolls over the rounded edge 1. The roller I25 is then seated in the recess I 23 by the bias of the spring I35.

The motor mechanism has been illustrated and described in connection with a particular type of circuit breaker structure; it will be readily understood however that the motor mechanism is also capable of usewith various other types of circuit breakers and switches and also with other forms of control devices.

While the invention has been disclosed in accordance with the provisions of the patent statutes, it is to be understood that various changes in the structural details thereof may be made without departing from the spirit of the invention. It is desired, therefore, that the-language of the appended claims be given the mined safe value and resettable after automatic disengagement by operation of said power means, and means operable to disengage said clutch to release said member from said power means to permit manual operation of said member.

2. In combination, a control device having a control member movable back and forth to a plurality of controlling positions, a motor mechanism for operating said control member in either direction to move said member to any of its controlling positions comprising an oscillatable actuating member, a motor for driving said actuating member back and forth, means including a releasable and resettable clutch device for normally connecting said control member to said actuating member for movement thereby, said clutch device permitting over-travel of said actu- 3. In combination, a circuit breaker having relatively movable contacts and a mechanism including an operating member movable back and forth to open and to closed position for opening and closing said contacts, power means operable to selectively move said member to open and to closed position, means normally connecting said power means to said member including a releasable and resettable clutch which is operable to automatically release said member from the power means when the load imposed on the operating member exceeds a predetermined safe value.

4. In combination, a circuit breaker having relatively movable contacts and an operating member movable back and forth for opening and closing said contacts, a motor mechanism for operating said member back and forth to open or to close said contacts, means releasably coupling said mechanism to said member so as to permit overtrayel of said mechanism relative to said member, said coupling means being operable to automatically release said member from said mechanism whenever the load imposed on said member exceeds a predetermined safe value, and

a manual operating member removably mountable on said coupling means operable to release said breaker operating member from said motor mechanism to permit manual operation thereof.

5. In combination, a circuit breaker having relatively movable contacts and actuating means including an oscillatable operating member movable back and forth for opening and closing said contacts, a motor mechanism for operating said member back and forth to effect opening or closing of said contacts comprising a rocking lever, motor means for oscillating said lever, means coupling said member to said lever for movement thereby, said coupling means yieldably permitting limited overtravei of said lever relative to said member and being operable to automatically release said member from said lever whenever the load imposed on the member exceeds a predetermined valuei 6. In combination, a circuit interrupter having relatively movable contacts and actuating means including an oscillatable member movable back and forth for opening and closing said contacts, a motor mechanism for operating said member back and forth to open or to close said contacts comprising a rotatable crank, a motor for driving said crank, a rocking lever connected to said crank for oscillation thereby, an operating lever secured to said oscillatable member, and releasable and resettable clutchmeans normally connecting said operating lever to said rocking lever for movement thereby, said clutch means being operable to automatically disconnect said operating lever from said rocking lever when the load imposed thereon by said rocking lever exceeds a predetermined maximum safe value.

7. In combination, a circuit interrupter having relatively movable contacts and actuating means including an oscillatable member movable back and forth for opening and closing said contacts, a motor mechanism for operating said member back and forth to open or to close said contacts comprising a rotatable crank, a motor for driving said crank, a rocking lever connected-to said crank for oscillation thereby, an operating lever detachablysecured to said oscillatable member, and a releasable and resettable clutch means normally connecting said operating lever to said rocking lever for movement thereby, said clutch means permitting overtravel of said rocking lever relative to said operating lever.

8. In combination, a circuit interrupter having relatively movable contacts and actuating means including an oscillatable member movable back and forth for opening and closing said contacts, a motor mechanism for operating said member back and forth to open or to close said contacts comprising a rotatable crank, a motor for driving said crank, a rocking lever connected to said crank for oscillation thereby, an operating lever secured to said oscillatable member, and a releasable and resettable clutch means normally connecting said operating lever to said rocking lever for movement thereby, said clutch means yieldably permitting limited overtravel of said rocking lever relative to said operating lever, and being operable to automatically release said operating lever from said rocking lever when the load imposed on said operating lever by said rocking lever exceeds a predetermined maximum safe value, and said clutch means being resettable following release by operation of said motor.

9. In combination, a circuit breaker having relatively movable contacts and means including an oscillatable operating member movable back and forth to open and to closed position for opening and closing said contacts, a motor mechanism operable to selectively move said member to open or to closed position comprising an oscillatable actuating member, a motor for driving said actuating member, means including a releasable and resettable clutch device having a normal position in which it normally connects said breaker operating member to said actuating member in proper position relative to said actuating member for movement thereby, said clutch device permitting overtravel of said actuating member relative to said operating member and acting to assist in stopping rotation of said motor when said actuating member reaches the end of its stroke, and said clutch device being operable to automatically release said breaker operating member from said motor driven actuating member whenever the load on said breaker operating member exceeds a predetermined amount and being resettable to said normal position connecting said members, by the operation of said motor mechanism.

10. In combination, a circuit interrupter having relatively movable contacts and means including an oscillatable operating member movable back and forth for opening and closing said contacts, a motor mechanism for operating said member back and forth to open or to close said contacts comprising an oscillatable actuating member, a motor for driving said actuating member, a releasable and resettable clutch means normally connecting said operating member to said actuating member for movement thereby, said clutch means permitting overtravel of said actuating member relative to said operating member and being operable to automatically release said operating member'from said mechanism whenever the load imposed on saidoperating member exceeds a predetermined safe value, and means operable to disengage said clutch to release said operating member from said mechanism to permit manual operation of the interrupter.

11. In combination, a circuit interrupter having relatively movable contacts and actuating means including an oscillatable operating member movable back and forth for opening and closing said contacts, a motor mechanism for operating said member back and forth to open or to close said contacts comprising an oscillatable aetuating member, a motor for driving said actuating member, means releasably coupling said members for movement together, said coupling means permitting overtravel of said actuating member relative to said operatingmember and being operable to automatically release said operating member from the actuating member whenever the load imposed on said operating member exceeds a predetermined safe value, and means removably mounted on said operating member operable to release said operating member from said actuating member to permit manual operation of the interrupter.

12. In combination, a circuit interrupter having relatively movable contacts and actuating means including an operating member movable back and forth to open and to closed position for opening and closing said contacts, a motor mechanism for selectively moving said member to open and to closed position comprising an oscillatable actuating member, a motor for driving said actuating member, releasable and resettable coupling means for releasably coupling said operating member to said actuating member for movement thereby, said coupling means permitting overtravel of said actuating member relative to said operating member and being operable to automatically release said operating member from the actuating member whenever the load imposed thereon by said actuating member exceeds a predetermined safe value, said coupling means comprising a spring biased roller carried by 'one of said members for engaging a single roller receiving recess provided in the other of said members.

13. In combination, a circuit interrupter having relatively movable contacts and actuating means including an oscillatable operating member movable back and forth to open and to closed position for opening and closing said contacts, a motor mechanism for operating said member to open and to closed position comprising an oscillatable actuating member, a motor for driving said actuating member, one of said members being provided with a single roller receiving recess and the other of said members carrying a spring-biased roller for engaging said reces to normally couple said operating member to said actuating member for movement thereby, the bias of said roller and the edges of said recess being such that said roller rides out of said recess to release said operating member from the actuating member whenever the load imposed on said operating member exceeds a predetermined safe value, and said roller being resettable in said single recess following release, by the operation of said motor.

14. In combination, a circuit interrupter having relatively movable contacts and actuating means including an oscillatable operating member movable back and forth for opening and closing said contacts, a motor mechanism for operating said member back and forth to open or to close said contacts comprising an oscillatable actuating member, a motor for driving said actuating member, one of said members being provided with a roller receiving recess and the other of said members carrying a spring-biased roller for engaging said recess to normally couple said operating member to said actuating member for movement thereby, the bias of said roller and the edges oisaid recessbeingsuchthatsaidroller rides out of said recess to release said operating member from the actuating member whenever the load imposed on said operating member exceeds a predetermined safe value, and means operable to withdraw said roller from said recess to release said operating member from the mechanism to permit manual operation of said operating member.

15. In combination, a circuit breaker having relatively movable contacts and actuating means including an operating member movable back and forth for opening and closing said contacts and a trip device for eiifecting opening of said contacts independently of the pomtion 0! said member, a motor mechanism ior operating said member back and forth to open or to close said contacts and to reset the breaker actuating means following a tripping operation, said mechanism comprising an actuating member, a motor for driving said actuating member, means including a releasable and resettable clutch device for releasably connecting said operating member to said actuating member for movement thereby, said clutch device permitting over-travel oi said actuating member relative to said operating member and being operable to automatically release said operating member from the actuating member when the load imposed thereon exceeds a predetermined safe value.

16. In combination, a circuit breaker having relatively movable contacts and means including an oscillatable operating member for opening and closing said contacts, a motor mechanism for operating said member back and forth comprising an operating lever detachably secured adjacent one end to said operating member, a rocking lever pivoted on said operating lever adjacent said one end, motor-driven means connected to said rocking lever for rocking the same, means releasably coupling said operating lever to said rocking lever for movement thereby, said releasable coupling means permitting overtravel of said rocking lever relative to said operating lever and being operable to automatically release said operating lever irom said rocking lever whenever the load imposed on said operating member exceeds a predetermined safe value, said coupling means comprising a spring-biased roller carried by one of said levers for engaging a roller receiving recess provided in the other of said members.

17. In combination, a control device having an oscillatable control member movable to a pinrality of controlling positions, a motor mechanism for selectively operating said member back and forth to any of its controlling positions comprising an oscillatable actuatingmember, a motor for driving said actuating member, means including a releasable and resettable clutch device having a normal position in which it normally connects said control member to said actuating member in proper position relative to said actuating member for movement thereby, said clutch device permitting overtravel of said actuating member relative to said control member and being operable to assist in stopp fl rotation of said motor when said actuating member reaches the ends of its stroke, and said clutch device being operable to release said control member from said.

actuating member when the load on said control member exceeds a predetermined amoimt, said clutch being resettable to its normal position connecting said members, by the operation of said motor mechanism.

18. In combination, a control device having an oscillatabie control member movable to a plurality of controlling positions, a motor mechanism for selectively operating said member to any of its controlling positions comprising an oscillatable actuating member, a motor for driving said actuating member, means including a releasable and resettable clutch device tor normally connecting said control member to said actuating member for movement thereby, said clutch device permitting overtravel 01 said actuating member relative to said control --member and being operable to assist in stopping rotation of said motor when said actuating member reaches the ends of its stroke and to automatically release said control member iro said actuating member whenever the load imposed on said control member exceeds a predetermined sai'e value.

19. In combination, a control device having an oscillatable control member movable to a plurality of controlling positions, a motor mechanism for selectively operating said member to any of its controlling positions comprising anoscillatable actuating member, a motor for driving said actuating member, means including a clutch device for normally connecting said control member to said actuating member for movement thereby, said clutch device permitting overtravel of said actuating member relative to said control member and being operable to assist in stopping rotation of said motor when said actuating member reaches the ends of its stroke and to automatically release said control member from said actuating member whenever the load imposed on said control member exceeds a predetermined safe value: and means operable to disengage said clutch to eiiect release oi said control member from said mechanism to permit manual operation of said control member.

20. A releasable and resettable clutch device for normally connecting and osciliatable operating member of a circuit breakerto an oscillatable actuating member of a motor operating mechanism for operating the circuit breaker, said clutch device comprising means carried by one of said members forming a single arcuate roller receiving recess, and a spring biased roller carried by the other of said members and engaged in said recess, said clutch device permitting limited overtravel of said actuating member relative to said operating member and being operable to automatically release said operating member from said motor operating mechanism whenever the load imposed on said operating member exceeds a predetermined safe value, and meansmanuallyoperableto from said recess to permit manual operation oi said breaker operating member free of said motor operating mechanism.

21. A releasable and resettable clutch device for normally connecting an oscillatable operating memberoia circuitbreaker to an oscillatable actuatingmember oi amotoroperatingmechanism for operating the circuit breaker, said clutch devicecomprisingmeanscarriedbyoneoisaid members forming a single arcuate roller receiving ,andaspringbiasedrollercarriedby the other otsaidmembers andinsaidrecess, said clutch device permitting limited overtravel oi said actuating member relative to said operating member and being operable to automatically release said operating member from said motor operating wherever the load imposed on said operating member a predeterresettable in said roller receiving recess after release of said clutch, by operation of said motor mechanism.

22. In combination, a circuit breaker having relatively movable contacts and actuating means including an oscillatable operating member movable back and forth to open and to closed positions respectively for opening and closing said contacts, a motor operating mechanism operable to selectively move said breaker operating member to open or to closed position comprising an oscillatable motor driven actuating member movable back and forth to open and to closed position corresponding to the open and closed positions of said breaker operating member, motor means operable through a definite cycle for moving said actuating member to open or to closed position and a releasable and resettable clutch device having a normal position in which it normally connects said breaker operating member to said motor driven actuating member in proper relation to said actuating member for movement thereby, said clutch device being automatically releasable to release said breaker operating member from said motor driven actuating member whenever the load on said breaker operating member exceeds a predetermined amount, and said clutch device being resettable to said normal position connecting said members by the operation of said motor means.

23. In combination, a circuit breaker having relatively movable contacts and actuating means including an osciliatable operating member movable back and forth to open and to closed positions respectively, for opening and closing said contacts, a motor operating mechanism operable to selectively move said breaker operating member to open or to closed position comprising an oscillatable motor driven actuating member movable back and forth to open and to closed position corresponding to the open and closed positions of said breaker operating member, motor means operable through a definite cycle for moving said actuating member to open or to closed position and a releasable and resettable clutch device comprising a spring biased roller carried by one of said members for engaging in a single roller receiving recess in the other of said members to normally connect said breaker operating member to said motor driven actuating member in proper relation to said actuating member for movement thereby, said roller being automatically disengageable from said recess to release said breaker operating member from said motor driven actuating member whenever the load on said breaker operating member exceeds a predetermined amount, and said roller being resettable in said single recess to reconnect said members, by the operation of said motor means.

LEON R. LUDWIG. TURE LINDSTROM.