US2460758A - Lockout and alarm device for circuit breakers - Google Patents

Description

Feb, 1, 1949. H H LAWSQN 2,460,758

LOCKOUT AND ALARM DEVICE F-QR CIRCUIT BREAKERS Filed March 25, 1946 Fig. I.

His Attorney.

Patented Feb. l, 194

LOCKOUT AND ALARM DEVICE FOR CIRCUIT BREAKERS Harold H. Lawson, Philadelphia, Pa., assignor to General Electric Company, a corporation of New York Application March 23, 1946, Serial No. 656,568

(Cl. f77-311) 5 Claims. 1

My invention relates to improvements in lockout and alarm devices for circuit breakers and more particularly for circuit breakers which are provided with automatic tripping means for efecting their opening under abnormal conditions.

Circuit breakers have been provided with alarm switches so arranged as to effect the ringing of a bell, the lighting of a lamp, the operation of an annunciator drop and the like when tripped automatically. The arrangements with which I am familiar, however, are unsatisfactory. The addition of a manually operated cutoff switch in the alarm circuit to open it without reclosing the circuit breaker is unsatisfactory because, if an operator upon reclosing a circuit breaker, failed to restore the manually operated switch at the same time to correspond to the circuit breaker closed position, then an erroneous indication would be presented. This discrepancy between the circuit breaker closed position and alarm indication of circuit breaker open position might readily result in damage to both apparatus and personnel. Also, with either of the foregoing arrangements, an alarm is given whether the circuit breaker is tripped automatically or manually. Moreover, arrangements with which I am familiar are not economical because of the amount of wiring and other features involved.

An object of my invention is to provide an improved lockout and alarm device for circuit breakers so that after being automatically tripped the circuit breaker cannot be reclosed before the alarm indication of circuit breaker open position is cleared. Another object of my invention is to provide an improved lockout and alarm device f which is relatively simple in structure and operation and which Will selectively differentiate be tween automatic tripping and manual tripping of the circuit breaker. Still another object of my invention is to provide an improved lockout and alarm device which is readily adaptable to various circuit breakers and especially the tripping means associated therewith. A. further object of my invention is to provide an improved automatic circuit breaker lockout and alarm device which is particularly adapted for manually resetting Without any possibility of blocking or interfering with the operation or Calibrating of the automatic tripping mechanism of the circuit breaker. These and other objects of my invention will appear in more detail hereinafter.

In accordance with my invention, I provide in a manually reset lockout and alarm device for a circuit breaker provided with a tripping element and automatic actuating means therefor. means Cal for maintaining the tripping element in the tripped position only when operated thereto by the automatic tripping means in consequence of the operation thereof. For this purpose, I provide a lockout member biased for movement from an initial position to a nal position into holding engagement with the circuit breaker tripping element to prevent reclosing of the circuit breaker only after it has been automatically tripped. To permit reclosing of the circuit breaker, I provide manual actuating means adapted to be operated to return the lockout member against the bias thereon to the initial position and means including a latch for holding the lockout member in the initial position and arranged to be released only upon operation of the circuit breaker automatic tripping means whereby to effect movement of" the lockout means to its nal position. Also in accordance with my invention, I provide the lockout member with alarm means to provide an indication of the automatic tripping of the circuit breaker.

My invention will be better understood from the following description when considered in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

In the accompanying drawing, Fig. l is a side elevation illustrating an embodiment of my invention as applied to a circuit breaker, shown only in part, with the parts presented in the circuit breaker closed position, and Fig. 2 is a side elevation similar to Fig. l with the parts presented at the moment of tripping the circuit breaker.

For the purpose of illustrating my invention, I have shown an embodiment thereof as applied to a circuit breaker secured to a base I of insulating material and shown only in part as comprising a supporting frame 2. As far as my invention is concerned, the particular type of circuit breaker is immaterial, but I have further illustrated the circuit breaker as including a tripping mechanism comprising a tripping shaft or element 3 which is supported in the frame 2 and is provided with a tripping arm 4. The shaft 3 is biased to the holding position shown in Fig. l by a spring 5. For actuating the tripping shaft 3 to the releasing position, the circuit breaker is also shown as provided with automatic electroresponsive actuating means comprising a U- shaped magnet 6, an energizing winding 1 and an armature 8. The magnet 6 is secured to the base I by suitable means such as screws 9. For current response, the Winding 1 is connected between the lower stud I0 of the circuit breaker and the lower contact block H so as to be in series relation with the circuit through the circuit breaker. The armature 8 is pivotally supported at I2 in a bracket I3 which is shown as secured to the magnet 6 and to a supporting bracket I4 suitably secured to the circuit breaker frame 2. Also the armature 8 is biased to the unattracted position by suitable means, not shown, Which may be adjusted; asiwellfknown to gth'eart; for controlling the pickupv point' or response ofthe tripping means. to the tripping or releasing position upon movement of the armature 8 from theun'attractedv position shown in Fig. 1 to the attracted position' shown in Fig. 2, the armature is provided with.

a hook-shaped extension lwhichisarranged to engage the lower end of a tripping lever I6 pivotally mounted at in a bracket I8 secured to the circuit breaker frame 2. The 'leverIE' is provided" with a curved upper portion I3 which is arranged upon clockwise movement of the lever I6 to engage the tripping arm 4 and to turn it Avcounterclockwise tothe' releasing' 'position shown in Fig.

2.' For" adjustment purposes,v a screw 20 is.

mountedin theV bracket I8* for contact-with the lever I6 to'v establish its' non-tripped position shown in Fig. 1.

In accordance with my invention, I provide means for maintaining the circuit .breaker tripping shafft or element 3 in the tripped position, shown in Fig. 3, after actuation thereto in consequence of the operation of the. electro-responsive tripping means. As shown, this mean-s is a lockout member 2| which is mounted Ifor movefrom an initial position, shown in'Fig. 1,

to a nalposition, shown in Fig. 2, into holding :1

engagement with the tripping shaft 3 through the medium of 'an arm 22 suitably secured thereto as-by abolt 23. Also', in accordance with my invention, the lockout member 2| functions as'an alarm control or switching member and is mounted for' .rectilinear movement in a suitably' shapedbl-ock 2 4--v of insulating material secured to ythe supporting bracket I4 as by a bolt' 25. Themember 2| is biased tothe trip element holding or na'l position by suitable mean's'such` as a spring 23 which,V as shown, is aroundthe member between the top of the .block 24 and nuts 21 on the member foradjus-tment purposes.-

InY the trip element holdingposition, lthe member 2I'isalsoV arranged to completethe circuit 28 of suitable alarm and indicating devices such as la' bell 29 and a lamp 3U. the member 2| is arranged to actua-te suitable contact means such' as a movable contact 3|, which, as shown, is'resiliently supported on the member and is arranged to bridge stationary contacts 32 mounted on the block 24 andi provided`with terminals 33 to which the circuit conductors 28 are connected. For'energizing' the alarm circuit 28, a` suitable sourcev of electromotive vforce such as a battery 34 is provided;A

Further in accordance with my invention',.1

provide actuating means adapted. .to be operated toreturnthe lockout member 2| to the initial position yshown .in Fig. 1 agains-tthe bias of the spring 26' so that the tripping 'shaft 3 may'returnto vthe latching position shown `in Fig. 1 under the bias of the spring 5. As shown, this actuating means comprises an element 35 which is connected'to the lockout member 2| for movement. simultaneously therewith and relatively thereto vand is movable in one direction to return' the member lto its ,initialposition For vthis purpose;f the actuating I or .resetting element' 35. which' is roughly U-shapedis pivoted'at 3`6jon For actuating the tripping shaft 34 For this purpose,

the supporting bracket I4 and is also loosely pivotally connected to the member 2| by a pin 3l -on the member and projecting into a slot 38 in the element so that it can have freedom of angular movement Without interfering with the linear movement of the member.

For actuating the elementl 3511s adirection, yclockwise as viewed the-drawing; tof` return the lockout member 2| to its initial position, I provide means such as a push rod 39 which, as shown, Yis linearly movable from right to left as viewed in-FigZ-to engage the leg 4I) of the resetting' element 35 and turn it clockwise about its pivot 3E. As shown, the. push .rod 39 is mounted on the supporting bracket I4 and bias-ed for movementfromleft to right away from the element .35 by suitable means such as a spring 4|. Fore'ase' manipulation, the push rod 39 is provided with a knob or handle 42.

For holding the resetting element 35 in a position to maintain the lockout member 2| in its initial position, I provide meansy which is arranged to be released upon operation ofY the electrore'sponsive tripping means whereby to eiectv movement' of the member to ilts nalor trip. holding. position under the actionvof the spring. 2li. 43"which, as shown, is mounted.on-aQslraftlv 44 arranged to turn about the same pivotal' axis' I2 as the armature' 8' does and -to' engage .the

leg-65' of the actuating element 35fasshown in Fig. l. On :the shaft 44, there is mounted'la'lever 43' having an arm 4i' extending outwardly froml the plane of thedrawinginto the path of movementof the armature 8' so'that upon movement' thereof to the' attracted position, the latch 43'A is released to permit movement of the element' 33 and' the member 2| under the bias' of the' spring' 2'6. For resetting'the latch 43"to"the.hold2 `ing position, it may. be biased by suitable means such as' a spring 48 attached'to the arm`4`i'v and'.

tothesupportingbracket i4. Also', I- have shown the shaft 44 as provided with a counterbalancing weight 49'Lwh`ich tends to turn the shaft counterclockwise" and to render it less susceptible to."

movementirom shocks. For establishing the 'de-k sired latfching; I provide an adjustable stop '50" which, as shown, `is monntedon the supporting" bracket arm 46.'

Assuming 'now ythe parts positioned as shown inFig; 1 and: thatthe circuit breaker is closed',` then. theresetting `element 35 is maintained'in the holding position againstthe bias of the' spring 25-'by the'latch 43; Whencurrent flo-wsin the I4; in the path of movement of the winding lt'o Ian amount sufficient to `attract the 1 armature 8; the tripping. lever i3 will be engaged' by the hook-shaped V'extensionv i5 on' the armattu'eand turned clockwise suiiiciently't'o rotate the tripping arm 4" to the releasing' position' Substantially against the' biasof'the spring 5. simultaneously therewith, the latch 43` is released from the arm 450i the resetting member 35sothat the lockout and operating member 2|'A is free to move upwardly under the bias of the springZii'l from the initial position shown in Fig. 1 tov the trip holding positionshown' in Fig'. 2. At the same time; th'ebridging contact 3l en.- gages the .stationary contacts 32 to complete the alarm circuit 23' thereby lighting the lamp. 3|l'v and ringing' the'bell' 39, ifboth of these devices are provided.v As 'long as the lockout and alarm'member 2i remains .in the trip holding position in engagementwith the arm 22`onthe tripshaft 3, the circuit breaker .cannot be re- For this purpose, I provide a latch` closed because the trip shaft is held in a position such that it cannot be moved Ito the circuit breaker mechanism holding position. Before the circuit breaker can be closed, the actuating element 35 must be rotated clockwise so that the latch 43 can fall in behind the end of the arm 48. This clockwise movement of the actuating element 35 is effected by ypushing in on the knob 42 to engage the arm 40 so that it can be rotated sufftciently to come into the latching position, as shown in Fig. 1. With this arrangement, it will be obvious that before the circuit breaker can be reclosed the alarm indication, showing ythat the circuit is open after an automatic tripping, must be annulled.

From the foregoing, it will be apparent to those skilled in the art that devices, embodying my invention, may be used on single pole or multi-pole circuit breakers wherein all poles open when one pole is tripped and only one device is necessary to accomplish the desired results where all poles trip. Moreover, as far as my invention is concerned, it is immaterial whether the automatic tripping means is electroresponsive, such as the overcurrent device illustrated, or is pressure or float operated or the like.

While I have shown and described my invention in considerable detail, I do not desire to be limited to the exact arrangements shown, but seek to cover in the appended claims all those modifications that fall within the true spirit and scope of my invention.

What I claim as new and desire to secure by Letters Patent of the United States is:

1. A manually reset lockout and alarm device for a circuit breaker trip mechanism having automatic tripping means, comprising an auxiliary latch released by said automatic tripping means, lockout means including a member held under control of said latch in an inactive position and having biasing means for moving said member therefrom upon release of said latch to a lockout position for holding said mechanism to prevent reclosure of the circuit breaker, alarm switching means operated by said member in said lockout position, and manual reset means for returning said member to said inactive position- 2. In a circuit breaker trip control and alarm mechanism, a circuit breaker trip member having a tripping positionfor opening the circuit breaker and preventing reclosure thereof, biasing means for biasing said trip member to an inactive position, automatic tripping means for moving said member to the tripping position, a lockout member having biasing means for moving said lockout member to a lockout position for holding said trip member in said tripping position thereof to prevent reclosure of the circuit breaker, alarm switching means operated by said member in said lockout position thereof, a latch for holding said lockout member in an inactive position, means under control of said automatic tripping means for releasing said latch, and manual reset means for returning the lockout member to said inactive position.

3. In a circuit breaker trip control and alarm mechanism, a circuit breaker trip shaft rotatable to a tripping position for opening the circuit breaker and preventing reclosure thereof, biasing means for biasing said trip shaft to an inactive position, automatic tripping means for rotating said shaft to said tripping position, an arm on said shaft, a movable lockout member having biasing means for moving said lockout member to a lockout position in engagement with said arm to hold the shaft in said tripping position and thereby prevent reclosure of the circuit breaker, alarm switching means operated by said member in said lockout position thereof, a latch for holding said lockout member in an inactive position, means under control of said automatic tripping means for releasing said latch, and manual reset means for returning the lockout member to said inactive position.

4. In a manually reset lockout and alarm device for a circuit breaker having a tripping shaft and automatic actuating means therefor, an arm on said shaft, a member having biasing means for moving said member from an inactive position to a position for holding said arm in the tripped position of said shaft, alarm switching means operated by said member in the holding position thereof, control means for said member including a pivotally mounted element connected with said member for pivotal movement upon movement of said member between said positions, manual reset means for operating said pivotal element to return the member to the inactive position and a latch for engaging said pivoted element to maintain said member in its inactive position, said latch having a member operated by said automatic actuating means only upon operation thereof to trip the breaker for releasing said latch to effect movement of the biased member to said holding position.

5. In a manually reset lockout and alarm device for a circuit breaker provided with a trip shaft having two arms thereon and automatic actuating means for one of said arms, a member having biasing means for moving said member from an inactive position to a position for engagthe other arm to hold the trip shaft in the tripped position, alarm switching means, operated by the member in the holding position thereof, manual reset means including a pivotally mounted element connected with said member to return the member to its inactive position, a latch biased into engagement with said pivoted member to hold said member in its inactive position, and a member operated by said automatic actuating means for releasing said latch upon operation of the trip shaft to the tripped position.

HAROLD H. LAWSON.

REFERENCES orED The following references are of record in the file of this patent:

UNITED STATES PATENTS Number Name Date 1,848,853 Thumim Mar. 8, 1932 2,091,108 Sengebusch Aug. 24, 1937 2,227,506 Leonard Jan. 7, 1941

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