US3710298A

US3710298A - Drive mechanism for electrical circuit breakers

Info

Publication number: US3710298A
Application number: US00200767A
Authority: US
Inventors: H Strubin
Original assignee: Bbc Brown Boveri & Cie
Current assignee: BBC Brown Boveri AG Switzerland
Priority date: 1970-12-09
Filing date: 1971-11-22
Publication date: 1973-01-09
Anticipated expiration: 1990-01-09
Also published as: GB1320430A; FR2117424A5; DE7100451U; IT941986B; CA937615A; CH524889A; DE2100628A1; SE367091B

Abstract

A drive for the contact mechanism of an electrical circuit breaker includes a double-acting pneumatic motor coupled to the contact mechanism for effecting disengagement as well as engagement of the contacts which is driven by explosion gases generated by the firing of cartridges stored in magazines, the cartridges being fed automatically from the magazines into firing chambers provided in a rotationally mounted drum. Cartridge feed into and ejection from the firing chambers from the magazines is accomplished in alternation as the drum is rotated alternately in opposite directions, and each firing chamber is associated with a duct leading to a corresponding end of the motor cylinder so that when a cartridge is fired in one chamber, the motor piston is driven in one direction, and as the next cartridge is fired in the other chamber, the motor piston is driven in the other direction. The necessary alternate rotation of the drum in opposite directions is obtained from the explosion gases themselves.

Description

United States Patent [1 1 Striibin [54] DRIVE MECHANISM FOR ELECTRICAL CIRCUIT BREAKERS Harald Striibin, Neuenhof, Switzerland [73] Assignee: Aktiengesellschatt Brown, Boveri &

Cie, Baden, Switzerland [22] Filed: Nov. 22, 1971 [21] Appl. No.: 200,767

[75] Inventor:

[30] Foreign Application Priority Data Dec. 9, 1970 Switzerland ..18309/70 [52] US. Cl ..337/40l, ZOO/61.08 [51] Int. Cl. ..II0lh 37/76 [58] Field of Search ..337/285, 287., 283, 401, 409, 337/413, 402; 200/6l.08, 82 R 1 Jan. 9, 1973 Primary ExaminerRoy N. Envall, Jr. Attorney-Ralph E. Parker et a1.

[57] ABSTRACT A drive for the contact mechanism of an electrical circuit breaker includes a double-acting pneumatic motor coupled to the contact mechanism for effecting disengagement as well as engagement of the contacts which is driven by explosion gases generated by the firing of cartridges stored in magazines, the cartridges being fed automatically from the magazines into firing chambers provided in a rotationally mounted drum. Cartridge feed into and ejection from the firing chambers from the magazines is accomplished in alternation as the drum is rotated alternately in opposite directions, and each firing chamber is associated with a duct leading to a corresponding end of the motor cylinder so that when a cartridge is fired in one chamber, the motor piston is driven in one direction,

and as the next cartridge is fired in the other chamber, the motor piston is driven in the other direction. The necessary alternate rotation of the drum in opposite directions is obtained from the explosion gases themselves.

10 Claims, 6 Drawing Figures PATENTED JAN 9 I975 3.710 298 SHEET 1 UF 2 Pmamenm ems SHEET 2 OF 2 DRIVE MECHANISM FOR ELECTRICAL CIRCUIT BREAKERS This invention relates'to an improved drive for actuating the contacts of an electrical circuit breaker of the type wherein the contact actuating mechanism is coupled to the piston of a double-acting pneumatic motor of the reciprocating type which is driven by explosive gases generated by the firing of cartridges which contain the gas generating substances.

From the prior art is known a drive for the contact mechanism of electrical circuit breakers utilizing a double-acting pneumatic motor of the reciprocating type wherein the piston is driven by the ignition of an explosive gas, e.g. oxyhydrogen gas, supplied in alternation through valves to themotor cylinder at opposite sides of the piston and exploded by means of spark producing plugs. Such an arrangement is disclosed in German Patent No. 1,287,677. This type of drive obtains the oxy-hydrogen gas from an electrolysis apparatus attachedto the circuitsbreaker structure. However, this type of drive has the disadvantage that its operating capability is endangered due to the hazard of untimely ignition of the gas.

From the prior art is also known a type of drive for the contacts of circuit breaker of the gas blast type wherein the contact movement and are extinction between the contacts is produced by the firing of cartridges filled with an explosive substance, the spent cartridges being replenished from a loading clip in the manner of a self-loading gun. Such an arrangement is disclosed in German Patent No. 568,887. The drive for the contacts is essentially of the one-way type in that the explosion gases function only in the contact-disengaging operation of the circuit breaker, spring means being provided to return the contacts to their engaged position.

The principal object of the present invention is to provide an improved drive for the contact mechanism of an electrical circuit breaker wherein the piston of a double-acting pneumatic motor coupled to the contact mechanism for effecting disengagement as well as engagement of the contacts is driven by explosion gases generated by the firing of cartridges which are stored in magazines, the cartridges being fed automatically from the magazines into firing chambers provided in a rotationally mounted drum. Cartridge feed into and ejection from the firing chambers from magazines is accomplished in alternation as the drum is rotated alternately in opposite directions, and each firing chamber is associated with a duct leading to a corresponding end of the motor cylinder so that as a cartridge is fired in one chamber, the motor piston is driven in one direction, and as the next cartridge is fired in the other chamber, the motor piston is driven in the other direction. The necessary alternate rotation of the drum in opposite directions is obtained from the explosion gases themselves.

The foregoing as well as other objects and advantages inherent in the invention will become more apparent from the following detailed description of a preferred embodiment thereof and from the accompanying drawing wherein:

FIG. 1 is a view in side elevation of the improved circuit breaker contact actuating mechanism showing in general the double-acting pneumatic motor, the rotary drum and cartridge magazines;

FIG. 2 is a view in end elevation with a portion of the cartridge magazine structure shown in section;

FIG. 3 shows, at an enlarged scale, and in the direction of the arrow in FIG. 2, the magazine changing mechanism wherein one magazine when depleted is automatically replaced with a fully loaded magazine;

' jacent each other as depicted in FIG. 1, on an intermediate plate 3. Each dual magazine structure consists of two separate magazine units and the magazine units 1' and 1" of the dual magazine structure 1 are depicted in FIG. 2 since these two magazine units are the ones which are in actual use in accordance with the operating condition indicated in FIG. 1. The magazine units of the dual magazine structure 2 are identical with those of the dual magazine structure 1 and shift into the loading position after all of the cartridges in the

magazine units

1, 1" have been fired.

As shown in FIG. 2, the interior of each magazine 1 1 is provided with a spirally formed wall 4 which establishes a correspondingly formed spiral guideway 5 along which the cartridges 6 are advanced to the magazine outlet by means of a pin 7 in contact with the cartridge at the innermost point of the guideway 5 and which pushes against the spiral row of cartridges. Pin 7 is supported in a slot provided in a lid 9 of the cylindrical magazine casing, and this lid ismounted for rotation about its center on the magazine casing and is driven in rotation by means of a spring motor, the driving force being stored in a wound-up spiral spring 11 concentric with lid 9. As the lid 9 is rotated, pin 7 is free to move outwardly along its mounting slot and thus is enabled to follow the expanding spiral path taken by the cartridges. When all of the cartridges in the two

magazines

1, 1" have been ejected, the pin 7 will have moved radially outward in its slot to the position indicated in dashed lines in FIG. 2 and to such an extent that it will now actuate a tappet rod 12. Accordingly, as shown in FIG. 3, a nose 12a of the tappet rod which previously had been engaged in a slot in a retaining pin 13 is now released, causing pin 13 to be thrust away from the support plate 3 by the force stored in a compressed spring 14. Two other laterally spaced compressed springs 15, each having one end thereof bearing against a fixed abutment and the other end bearing against the intermediate support plate 3 for the magazine are then enabled to exert the force stored therein against the support plate 3 and shift the latter, and hence the magazines 1 and 2 along a pair of guide rails 16 until stopped by an abutment 17, in which position, the empty dual magazine 1 (magazine units 1', 1") will have been shifted out of the loading position and the full magazine 2 into the loading position. The pin 7 which follows the cartridges in the magazine may also be utilized to actuate a signalling means of known type, but not illustrated so that an alarm is set off when the magazines are emptied to a predetermined degree.

In FIGS. 1 and 2, the double-acting pneumatic motor 18 includes cylinder 19 in which a piston 20 connected to the contact mechanism of the circuit breaker is reciprocated by the explosive forces of the cartridges which are fired in a rotationally mounted drum 8 has been shown only generally by way of an elevational view. The structural details of these operating components are illustrated in FIGS. 4 to 6.

The double-acting piston 20 is guided for reciprocation in its working cylinder 19, and piston rod 21 is cou- 1 pled to the contact mechanism of the circuit breaker,

not shown, such that when the piston rod 21 moves in one direction, the circuit breaker contacts are disengaged while movement of the piston rod 21 in the opposite direction serves to effect a reclosure of the contacts. I

The double acting pneumatic motor 18 includes

driving chambers

22, 22 located at opposite ends of casing27 in which the drum is mounted for rotation about its axis. The other half of the drum periphery has a diameter somewhat less than the diameter of casing 27 so as to establish a slight arcuate gap therebetween, this gap being interrupted by a radially inward projection 25 on casing 27 that reaches essentially to the surface of the drum.

FIG. depicts the position of drum 8a wherein a cartridge 6 previously loaded into firing chamber 24 from magazine 1" has been moved into the firing position, while another cartridge 6 has just been loaded into the other firing chamber 26 from magazine 1. As soon as the cartridge 6 in chamber 24 is fired, the ensuing explosion gases discharged under pressure from the left end of the chamber, as viewed in FIG. 4, are forced through duct 23 into the driving chamber 22 and hence drive piston and hence piston rod 21 from left to right to actuate the circuit breaker contacts from closed to open position. At the same time, these same explosive gases work in the arcuate gap between projection and the chamber 24 and, after a delay to be later described, drive the drum 8a in a clockwise direction to the ultimate position indicated by the dashed line positionsof the

firing chambers

24, 26. The intermediate position of the drum 8a illustrated in FIG. 6 depicts the moment during the course of rotation at which the cartridge 6 is'being ejected from its opensided firing chamber 24by combined actions of centrifugal force and gas pressure, the outwardly moving cartridge serving to force a closure flap 28 outwardly against the counter action of a leaf spring 29 and hence open up a cartridge discharge chute. This completes and firing chamber 26 containing the next cartridge 6 one operational sequence of the switch contact actuatmagazine 1" is moved automatically into chamber 24,

to be fired will have been moved to a position in alignment with the other duct 23'. When this cartridge is fired, the explosive gases are discharged from chamber 26. and through duct 23 to the opposite driving chamber 22' and hence drive piston 20 from the right to the left as viewed in FIG. 4. At the same time, the excourse, discharged the spent cartridge shell during such movement. This completes another operational sequence of the switch contact mechanism, this time the piston rod 21 being driven from right to left until the position depicted in FIG. 1 is reached once again.

It will thus be evident, that as the cartridges are alternately loaded into the two

firing chambers

24 and 26 and then fired and ejected in alternation, drum 8a will be actuated in a reciprocating manner in the sense that it is driven first in one direction and then the other through a part of a revolution and piston 20'willbe reciprocated so as to'actuate the circuit breaker contacts to effect their'engagement and disengagement also in alternation.

A locking pin 31 is provided to cooperate, in the I limiting positions of the drum 8a with recesses 30 in the latter to prevent excessively early commencement of the rotary motion of the drum during firing. As shown in FIG. 4, this locking pin 31 is actuated into or out of the recesses 30 by means of a bellcrank lever 34, one arm of this lever being articulated to pin 31 and the other arm thereof being terminated in a follower roll 33 adapted to ride against a double cam provided on sleeve 32 which surrounds piston rod 21, the'arrangement of this train of components being such that lever 34 will not be actuated to effect release of locking pin 31 and therefore permit drum 8a to rotate, until the piston 20 and its rod 21 have nearly reached their end position, this being effected by means of a collar on piston rod 21 that picks up internal end flanges provided on cam sleeve 32 and shifts the sleeve near the end of the piston rod stroke.

The firing circuits for the cartridges 6 have not been illustrated since these are well known, as for example, by way of an electrical contact in the

firing chamber

24, 26 connected to complementary firing means provided within the cartridge.

I claim:

1. In a drive for the contact mechanism of an electrical circuit breaker, the combination comprising a double-acting pneumatic motor the piston of which is coupled to said contact actuating mechanism for effecting engagement and disengagement respectively of the contacts as said piston is reciprocated within its cylinder, a rotatable cylindrical drum including a pair of circumferentially spaced firing chambers established by longitudinally extending slots in the drum opening in the outward direction for receiving cartridges charged with a gas-forming explosive material, a cylindrical housing surrounding said drum and within which said drum is mounted for rotation about its axis, duct means correlated respectively with the gas discharge ends of said cartridge receiving slots and which lead respectively to opposite ends of said motor cylinder, a cartridge magazine individual to each of said cartridge receiving slots and which includes means for automatically feeding the cartridges therefrom when presented to the open side of said slots, said cartridges when fired in alternation in said slots serving to produce explosion gases which are delivered in alternation to the opposite ends of said motor cylinder, means including auxiliary firing chambers correlated respectively to each of said slots and which are formed in gaps provided between the periphery of said drum and its housing and which communicate with said slots whereby the explosion gases also effect rotation of said drum in alternate directions between limit positions defining the loading points of said cartridges into said slots, and means for ejecting each cartridge from its slot after the cartridge is fired and during rotation of said drum.

2. A drive for the contact mechanism of an electrical circuit breaker as defined in claim 1 wherein said gaps provided between the periphery of said drum and its housing to establish said auxiliary firing chambers for effecting rotation of said drum in alternate directions are produced by a reduction in the diameter of said drum between said slots and a projection extending inwardly from said housing to said reduced diameter portion of said drum.

3. A drive for the contact mechanism of an electrical circuit breaker as defined in claim 1 wherein said means for ejecting each cartridge from its slot after the cartridge is fired and during rotation of said drum is constituted by a spring loaded closure flap normally engaging the periphery of said drum and which is forced outwardly in the direction away from said drum by the combined actions of centrifugal force and the explosion gases.

4. A drive for the contact mechanism of an electrical circuit breaker as defined in claim 1 and which includes delay means controlled by movement of the piston rod of said doubleacting motor for delaying rotation of said drum until said piston rod nears the end of its stroke.

5. A drive for the contact mechanism of an electrical circuit breaker as defined in claim 4 wherein said delay means is constituted by a locking pin engageable in a recess provided in said drum, and means controlled by movement of the piston rod of said double-acting motor for releasing said locking pin from said recess.

6. A drive for the contact mechanism of an electrical circuit breaker as defined in claim 5 wherein said means controlled by the movement of said piston rod of said double-acting motor for releasing said locking pin from the recess in said drum as the latter nears the end of its stroke is constituted by a double cam sleeve surrounding said piston rod and which is provided with inwardly extending end flanges, said piston rod is provided with a collar engageable with said end flanges on said sleeve to shift the latter, and said cam on said sleeve actuates a cam follower roller carried by a lever coupled to said locking pin.

7. A drive for the contact mechanism of an electrical circuit breaker as defined in claim 1 wherein said cartridge magazines include a spirally configured path along which a row of said cartridges travel to the loading position into the slots provided in said drum.

8. A drive for the contact mechanism of an electrical circuit breaker as defined in claim 7 and wherein a follower feed pin engages the inner end of said row of cartridges, said feed pin being carried by the lid of the magazine which has a circular configuration, and said lid being mounted for rotation about its axis and urged into rotation by a spring drive.

9. A drive for the contact mechanism of an electrical circuit breaker as defined in claim 1 wherein said cartridge magazines are arranged in a plurality of pairs, said magazine pairs being mounted for movement in succession to the cartridge loading positions adjacent the cartridge receiving slots provided on said druin, and means controlled by the cartridge feed in the magazine pair at said loading position and which is responsive when said magazine pair has been emptied to shift said empty magazine pair from the loading position and present the next fully loaded magazine pair to the loading position.

10. A drive for the contact mechanism of an electrical circuit breaker as defined in claim 1 wherein each said cartridge magazine includes a spirally configured path along which a row of said cartridges travel to the loading position into the slots provided in said drum, wherein a follower feed pin engages the inner end of said row of cartridges to move the cartridges along said spiral path, wherein said cartridge magazines are arranged in a plurality of pairs, said magazine pairs being mounted for movement in succession to the cartridge loading position adjacent the cartridge receiving slots provided on said drum, and wherein there is further provided a means actuated by the said follower feed pin of one of said magazines of a magazine pair at said loading position and which is responsive when said magazine has been emptied to shift the empty magazine pair from the loading position and present the next fully loaded magazine pair to the loading position.

Claims

4. A drive for the contact mechanism of an electrical circuit breaker as defined in claim 1 and which includes delay means controlled by movement of the piston rod of said double-acting motor for delaying rotation of said drum until said piston rod nears the end of its stroke.

9. A drive for the contact mechanism of an electrical circuit breaker as defined in claim 1 wherein said cartridge magazines are arranged in a plurality of pairs, said magazine pairs being mounted for movement in succession to the cartridge loading positions adjacent the cartridge receiving slots provided on said drum, and means controlled by the cartridge feed in the magazine pair at said loading position and which is responsive when said magazine pair has been emptied to shift said empty magazine pair from the loading position and present the next fully loaded magazine pair to the loading position.