US2282228A - Circuit interrupter - Google Patents

Description

May 5, 1942. F. =3. JOHNSQN ETAL CIRCUIT INTERRUPTER Filed Oct. 24, 1940 2 Sheets-Sheet 1 INVENTORS FreaQr/tk 6. Johnson J Y Ba/rkn ATToRN Andrew H.

WITNESSES I M -M y 5, 1942- F. B. JOHNSON ETAL CIRCUIT INTERRUPTER Filed Oct. 24, 1940 2 Sheets-Sheet 2 NTORS Frederick A. 5205011 & And/aw H. Ba/rken a 34TORNEY WITNESSES Patented May 5, 1942 UNITED STATES PATENT OFFICE CIRCUIT INTERRUPTER sylvania Application October 24, 1940, Serial No. 362,596

17 Claims.

This invention relates to circuit interrupters, and, more particularly, to improvements in operating mechanisms therefor.

It is an object of our invention to provide a simple but highly eiilclent power driven operating mechanism for circuit interrupters which is effective to hold the contact structure in the closed circuit position against the reactive forces acting upon the contacts as a result of severe overloads or short circuits tending to move the contacts to the open circuit position.

It is also an object of our invention to provide a simple but effective operating mechanism for circuit breakers which will hold the contacts in the closed position against a thoughtless or casual manual attempt to move the contact structure to the open circuit position when the breaker is carrying load.

More specifically, it is an object of our invention to provide a power driven operating mechanism for circuit breakers wherein the power actuated driving means is coupled to a contact actuating member by a linkage so arranged that the linkage is irreversible in response to a force thereon by the contact actuating member so as to hold the contact actuating member in the closed position against accidental opening other than that initiated by the power actuated driving means.

Other objects and advantages will become apparent in the following description when considered in connection with the accompanying drawings, in which:

Figure 1 is a side elevation view partially in section showing a circuit interrupter embodying our invention;

Fig. 2 is an enlarged view of the operating mechanism of the circuit interrupter shown in Fig. 1;

Fig. 3 is a different view of the operating mechanism shown as viewed at right angles to that iilustrated in Fig. 2; and

Fig. 4 is a fragmentary view of another linkage arrangement that may be used in an operating mechanism in carrying out our invention.

The circuit interrupter shown in Figure 1 is of the air blast type and has been selected to illustrate the novel features of our operating mechanism. It will, of course, be understood that the mechanism forming the basis of the instant invention is broadly applicable to circuit interrupters, in general, irrespective of the particular means employed to extinguish the arc, though its specific features are designed to cooperate particularly with an air blast interrupter of the type shown. As the description of the circuit interrupter and the operating mechanism proceeds, it will also be apparent that the particular means employed to actuate the operating mechanism have also been selected for illustrative purposes and that the particular action of the operating mechanism is not in its broadest aspects dependent upon the means for bringing about operation of the mechanism.

More particularly, the structure shown in Fig. 1 includes a reservoir 5 having a short flanged conduit 1 extending from the upper end thereof on which is mounted a valve housing 9. Rising from the valve housing 9 is a tubular insulator I I, the upper end of which extends into and supports in part an arc extinguishing device 13. Further support of the arc extinguishing device 13 is given by the insulator member IS. The are extinguishing device l3 may be of any well known type adapted to bring about the eflicient extinction of arcs when subjected to a cross blast of compressed gas and in this instance may include a stationary contact assembly as shown at H adapted to cooperate with a movable contact IS. The movable contact I9 is pivotally supported at 2| for swinging movement with respect to a conducting bracket 23. External circuit connections to the interrupter may be made through terminals 25 and 21 secured respectively to the stationary contact assembly I1 and the conducting bracket 23. Thus when the interrupter is in the closed circuit position, as shown in Fig. 1, a conducting circuit is established from the terminal 25 to the terminal 21 by way of the stationary contact assembly I1, the moving contact l9 and the conducting bracket 23.

The moving contact I9 is caused to be moved to open and closed circuit positions by means of a pull rod 29 preferably of insulating material pivoted at 3| to an intermediate portion of the contact and at 33 to the free end of a crank arm 35. The crank arm 35 is rigidly secured to a shaft 31 journalled in a support 39 carried by the reservoir 5. The crank arm 35 may be actuated by a second crank arm 41 rigidly secured to the shaft 31. Coupled to the crank arm 41 by means of a linkage generally indicated at 43 is a compressed air actuated operating mechanism generally indicated at 45. The compressed air driven mechanism 45, for example, may include a cylinder 41 having a piston 49 operative therein and a connecting rod 5| extending upwardly from the cylinder 41 which is coupled at its upper end to the linkage 43. The linkage 43 as more clearly shown in Figs. 2 and 3, includes a pair of relatively short links 53 pivoted by a pin 55 to the upper end of the connecting rod 5|. other end of the links 53 are coupled by a pin 51 to a single link 59 also of relatively short length which, in turn, is coupled to the crank arm 4| by a pin 6|.

Disposed on the upper end of the operating cylinder 41 is a pair of guide members 63 having slots 65 formed therein. The pins 55 and 51 are also provided with guide rollers 61 and 69 adjacent their outer ends, as shown, and are so disposed as to be operative within the guide slots 65. The upper ends of the guide slots 65 have a somewhat greater width than the remaining portions thereof so as to form a shoulder 1|, the purpose of which will be more fully explained hereinafter.

Compressed gas for actuating the driving means 45 is controlled by suitable electromagnetically operated valve mechanisms 13 and 15 which, respectively admit compressed gas from the reservoir 5 to the upper and lower sides of the piston 49 to effect either opening or closing movement of the operating mechanism as desired. Thus, if it is desired to open the interrupter by means of the power actuated mechanism 45 either in response to a manual control of the compressed gas to the cylinder 41 or in response to an automatic control as a result of a tripping impulse received by the electromagnetically actuated valve 13, the latter will be opened to cause compressed gas to be admitted to the upper end of the cylinder 41, thereby driving the piston 49 downwardly carrying with it connecting rod 5| which, in turn, actuates the crank arm 4| through the linkage 43 to cause a counterclockwise rotation of the shaft 31 and the crank arm 35 so as to move the pull rod 29 downwardly to move the movable contact I9 to the open circuit position. If during such movement the circuit interrupter is carrying load, an arc will be drawn between the stationary contact assembly l1 and the movable contact |9,which arc extends across the open end of the hollow insulator II and is quickly extinguished by a blast of compressed gas caused to flow through the hollow insulator II from the reservoir 5.

Control of the arc extinguishing blast in this instance may be obtained by a valve 15 disposed within the valve housing 9 and carried by a stem 11 extending exteriorly of the housing. The stem 11 may be actuated to the open position by a bell crank 19 pivoted at 8| to a bracket 83, as shown.

The bell crank 19 is also provided with a roller 85 adapted to be actuated by a cam 81 which in this instance is shown to form an integral part of the crank arm 35. It, therefore, follows that as the crank arm 35 is rotated in a counterclockwise direction, as viewed in Fig. l, the cam 81 will engage the roller 85 so as to rock the bell crank 19 in a clockwise direction about its pivot 8| to depress the valve stem 11 and open the valve 15, therefore. admitting a blast of are extinguishing gas from the reservoir 5 into the tubular insulator II. The cam 81 is so shaped that when the moving contact I!) has reached its full open position, valve 15 will again be permitted to close to shut off the arc extinguishing blast of gas.

It shall be noted that the bracket 93 has a stop member 89 thereon against which the crank arm 35 is brought to rest during the closing movement of the contact I9. In this fully closed position the pull rod 29 and the crank arm 35 form an overccnter toggle arrangement in that the coupling pin 33 is positioned slightly to the right of the line of centers between the coupling pin 3| and the pivot 31, thereby normally maintaining the moving contact l9 locked in the closed position against movement by forces exerted upon the contact arising from extremely heavy overload or short circuit currents which due to their magnetic reaction have a tendency to move the movable contact to the open circuit position. It will be noted, however, that in the event the operating mechanism fails to completely move the crank arm 35 into engagement with the stop 89, so that the coupling pin 33 does not move past center, then the contact l9 will no longer be locked in the closed position and will be subject to be opened by a reactive force caused by overload current passing through the interrupter as aforementioned.

The specific arrangement of the linkage 43, as more clearly shown in Fig. 2. however, prevents rotation of the actuating arms 4| and 35 to the open circuit position in that the guide rollers 69 disposed on the coupling pin 51 are caused to be seated against the shoulders 1| in the guide slots 65. It will be noted that any tendency for the crank arm 4| to actuate the link 59 will be to cause the link 59 to move substantially 1ongi tudinally, that is, in a direction defined by the pivot pins 51 and BI.

Linear motion of the link 59 is, however, arrested by the shoulders 1|, thereby locking the linkage mechanism 43 against movement as a result of application of force in the opening direction by the crank arm 4|. It should be noted, however, that the application of force by the piston 49 through the connecting rod 5| is in a downward direction and is transmitted to the coupling pin 51 through the links 53. The shoulders 1| in the guide slots 65 are so arranged that the guide rollers 69 are easily displaced therefrom and moved downwardly into the main part of the guide slots 65 in response to movement of the operating piston 49. In order to insure movement of the guide rollers 69 against the shoulders 1| at the end of the closing stroke of the operating mechanism, a spring 9| secured to each support 63 may be provided, as shown. The springs 9| are adapted to engage the rollers 69 urging them to the left, as viewed in Figs. 1 and 2, thereby causing the linkage 43 to assume a locked position at the end of the closing stroke of the interrupter.

In order to operate the interrupter to the open and closed circuit position manually, we have provided a hand operated lever which is adapted to be inserted in a suitable socket 91 secured to the shaft 31, as more clearly shown in Fig. 1. Thus by moving the hand operating lever 95 downwardly, shaft 31 would normally be rotated in a counterclockwise direction causing the movable contact l9 to be moved to the open circuit position in the same manner as previously described in connection with the power operation.

It will be noted, however, that since the guide rollers 69 are seated against the shoulder 1| rotation of the shaft 31 in the circuit opening direction is prevented, thereby preventing the careless or thoughtless operation of the interrupter to the open'circuit position by hand in the event that the interrupter is carrying load. Such a manual operation under load would be particularly dangerous if there should not be available a supply of fluid under pressure in the reservoir 5 to extinguish the arc. It it not necessary that the locking means, including the rollers 59 and shoulder II, be effective during power actuation of the contacts because of the fact that the piston 49 operating in cylinder 41 is supplied with fluid under pressure from the same reservoir 5 as supplies the blast for extinguishing the arc. This means that if there is no pressure for extinguishing the arc, there is also no pressure for opening the contacts by the power actuated means, and opening of the contacts by the power actuated means under such dangerous conditions is prevented. In order to operate the interrupter to the open circuit position by means of the lever 95, it is first necessary to move the guide roller 69 to the right against the bias of the springs 9|, so that the rollers will clear the shoulder II and move downwardly into the main portion of the guide slots 55. The mere fact that this operation requires additional manipulation other than the operation of the handle 95 immediately places the operator on guard so that an improper manual operation of the interrupter will not take place.

Our invention may also be carried out with a linkage arrangement of the form shown in Fig. 4. In this figure, the linkage 43 has been replaced by a link member IOI pivoted to the crank arm 4| by a pin I03. The upper end of the connecting rod 5| in this instance is provided with a guide roller I05 operative in the guide slots 55 of the supports 63. The guide roller I05 in this instance is made of sufiicient width to also engage the inner surface of a heart shaped opening I01 formed in the link member MI. The

support 53 is provided with a stop pin I09 which limits the movement of the link member as will be hereinafter more fully described.

The link |0I has an extension I on the left hand end thereof which is adapted to be brought against the stop pin I09 by the action of a biasing spring ||3 joining the right-hand end of the link WI and the crank arm 4|, as shown. Movement of the link I0| in a linear direction, that is substantially in a direction as determined by a line between the pivot pin I03 and the stop pin I09, is prevented by a shoulder ||5 engaging the stop pin I09. Thus when the interrupter is in the closed circuit position, the link |0| takes the position as shown in Fig. 4.

In this position it will be seen that any tendency to rotate the crank arm 4| in a counterclockwise direction will be frustrated by the action of the shoulder N5 of the link |0I against the stop pin I09. However, movement of the crank arm 4| by means of the power actuated operating mechanism is made possible due to the fact that action of the connecting rod 5| downwardly first causes guide roller I 05 to engage the inner surface of the opening I0'I to rotate the link |0| in a counterclockwise direction, so that the shoulder |I5 clears the stop pin I09 so as to permit the roller I 05 to move downwardly along the guide slots 65 to complete the circuit opening operation.

It will be obvious that, actuation of the connecting rod 5| upwardly along the guide slots 65 will cause a closing force to be transmitted through the link IM to the crank arm 4| to rotate the latter in a clockwise direction to effect closing the interrupter. The aperture I01 in the link |0| provides sufficient clearance for the roller I05 so that at the end of the closing stroke, the biasing spring |I3 will again cause the link I03 to reset with respect to the stop pin I09.

Although we have shown and described a specific circuit breaker structure, it is to be understood that the same is for the purpose of illustration, and that changes and modifications may be made by those skilled In the art without departing from the spirit and scope of the appended claims.

We claim as our invention:

1. In a circuit interrupter, contact means movable to open and closed positions, an operating member for actuating said contacts, a driving device, a linkage operatively coupling said driving device and said operating member, and guide means for said linkage including a surface along which one element of said linkage slides when moved by said driving device, said surface being arranged to arrest movement of said linkage in response to the application of a force thereon by said operating member.

2. In a circuit interrupter, separable contact means, an operating member for actuating said contact means to open and closed positions. manually operable means for actuatng said operating member, power actuated means for actuating said operating member, and means for locking said operating member against movement from a predetermined position In response to the application of force thereto by said manually operable means but not locking against movement from said predetermined position in response to the application of force thereto by said power actuated means.

3. In a circuit interrupter, separable contact means, an operating member for actuating said contact means to open and closed positions, manually operable means for actuating said operating member, power actuated means for actuating said operating member, said power actuating means including a mechanical coupling linked with said operating member, and means coacting with said coupling and operated when said contacts are in the closed position for holding sa d operating member against movement to the open position by said manually operable means but not holding said operating member against movement to open position by said power actuating means.

4. In an operating mechanism for circuit interrupters, a contact actuating member movable to open and closed positions, driving means for said contact actuating member, coupling means including a link for operatively connecting said driving means with said contact actuating member, and guide means along which said link is slidable having a notch arranged to cause said link to assume a locking position with respect to said contact actuating member when said member is in the closed position.

5. In an operating mechanism for circuit interrupters, a contact actuating member movable to open and closed positions, driving means for said contact actuating member, coupling means operatively connecting said driving means with said contact actuating member, said coupling means including a link member, and guide means arranged to limit motion of said link member to a substantially straight path in response to actuation thereof by said driving means and arranged to prevent substantial motion of said link member along another path, said link member and said contact actuating member being so arranged that movement of the latter toward the open position has a tendency to impart a substantial motion to said link member along said other path whereby opening movement of said contact actuating member is prevented in response to the application of a force thereto other than that imparted by said driving means.

6. In an operating mechanism for circuit interrupter-s, a contact actuating member, a driving member, coupling means connecting said driving member with said contact actuating member, means for oscillating said driving member to move said contact actuating member to open and closed positions, said coupling means including a linkage, and guide means along which one element of said linkage is slidable in a predetermined path of movement, locking means for holding said linkage at one end of said guide means at the end of the closing movement of said driving member to prevent movement of said contact actuating member to the open position except by movement of said driving member.

7. In a circuit interrupter, separable contacts, an operating member to actuate said contact to open and closed positions, a driving member, a linkage coupling said driving member and said operating member, a support member having a guide slot therein, a pilot member carried by said linkage and slidable in said slot, said guide slot having a recess for receiving said pilot member to lock said contact actuating member against movement to the open position, and means biasing said pilot member into said recess, said driving member being operative to move said pilot member against the action of said biasing means out of said recess to enable said contact actuating member to be moved to the open position.

8. In a circuit interrupter, separable contacts, an operating member to actuate said contacts to open and closed positions, a driving member, a link member pivoted to said contact actuating member and operatively coupled to said driving member, a support having a catch thereon, and a latch on said link member adapted to engage said catch for locking said contact operating member in the closed position, said driving member being operable upon movement to the open position to first rotate said link member to release said latch and to thereafter actuate said contact operating member to the open position.

9. In a circuit interrupter, contact means for opening and closing the circuit, actuating mechanism for said contact means including locking means, power operated means for moving said contact means to both open and closed positions irrespective of said locking means, and manually operated means for moving said contact means to closed position and releasably restrained by said locking means against moving said contact means to open position.

10. In a circuit interrupter, contact means movable to open and closed positions, actuating mechanism for said contact means including two operating means and locking means, one of said operating means being manually actuated to move said contact means to one of said positions where it is held by said locking means against movement to the other of said positions, and the other of said operating means being power actuated for moving said contact means to both open and closed positions without eifective restraint from said locking means.

11. In a circuit interrupter, contact means movable to open and closed positions, actuating mechanism for said contact means including two operating means and locking means, one of 'said operating means being manually actuated to move said contact means to one of said positionswhere it is held by said locking means against movement to the other of said positions, and the other of said operating means being power actuated for moving said contact means to both open and closed positions without effective restraint from said locking means, said locking means being releasable by an unlocking movement, separate from movement of said manually actuated operating means to move said contact means to said other position, and said manually actuated operating means being movable after said release of the locking means to move said contact means to said other position.

12. In a circuit interrupter, contact means for opening and closing the circuit, power actuated means, a train of mechanism operatively connecting said power actuated means to move said contact means to either open or close the circuit upon operation of said power actuated means, said train of mechanism including manually operable means connected to the train intermediate the power actuated means and the contact means, and means in the train intermediate the power actuated means and the manually operable means which is irreversible upon movement of said manually operable means but which permits movement in either direction by said power actuated means, said irreversible means being releasable by a movement other than reverse movement of said manually operable means to permit reverse movement by said manually operable means.

13. In a circuit interrupter, contact means for opening and closing the circuit, power actuated means, a train of mechanism operatively connecting said power actuated means to move said contact means to either open or close the circuit upon operation of said power actuated means, said train of mechanism including manually operable means connected to the train intermediate the power actuated means and the contact means, and locking means connected in the train for permitting movement to either open or close the contact means upon actuation of the power actuated means and for permitting movement to close the contact means upon operation of the manually operable means but locking against movement to open the contact means upon operation of the manually operable means.

14. In a fluid pressure operated circuit breaker, contact means for opening and closing the circuit, a reservoir for supplying fluid under pressure to aid in extinguishing the are which may be drawn upon opening the circuit, means operated by fluid pressure from said reservoir for closing said contact means, manually operated means operable to close said contact means without the use of the fluid under pressure in said reservoir, and locking means requiring a special releasing movement to permit said manually operated means to be operated to open said contact means at least when there may not be available fluid under pressure in said reservoir to aid in extinguishing the are which may be drawn upon opening said contact means.

15. In a fluid pressure operated circuit breaker, contact means for opening and closing the circuit, a reservoir for supplying fluid under pressure to aid in extinguishing the arc which may be drawn upon opening the circuit, means operated by fluid pressure from said reservoir for both opening and closing said contact means, manually operated means for moving saidcontact means, locking means for said manually operated means guarding against its improper operation at least when an arc may be drawn by said contact means and there may not be available in said reservoir fluid under pressure for extinguishing the are.

16. In a fluid pressure operated circuit breaker, contact means for opening and closing the circuit, a reservoir for supplying fluid under pressure to aid in extinguishing the are which may be drawn upon opening the circuit, means operated by fluid pressure from said reservoir for both opening and closing said contact means, manually operated means for moving said contact means, locking means for said manually operated means guarding against its improper operation at least when an arc may be drawn by said contact means and there may not be available in said reservoir fluid under pressure for extinguishing the arc, and said locking means permitting operation of said means operated by said fluid under pressure for both opening and closing said contact means.

17. In a fluid pressure operated circuit breaker, contact means for opening and closing the circuit, means including a reservoir for supplying fluid under pressure to aid in extinguishing the are which may be drawn upon opening said contact means, power operated means movable when there is fluid under pressure in said reservoir to both open and close said contact means, manually operabie means for moving said contact means to closed position without using fluid under pressure from said reservoir, and locking means guarding against the improper operation of said manually operable means to open said contact means at least when an arc may be drawn and there may not be fluid under pressure in said reservoir for aiding in extinguishing the are, but not preventing the operation of said power operated means when there is fluid under pressure in said reservoir.

FREDERICK B. JOHNSON. ANDREW H. BAKKEN.

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