US2076981A - Circuit breaker - Google Patents

Description

April 13, 193'?u R. A. @ROOK CIRCUIT BREAKER Filed March 28, 1954 5 Sheets-Shawl'l l April 13, 1937. R. A. cRooK ,2,0769983 CIRCUIT BREAKER Filed March 28, 1934 3 sheets-sheet 2 April 13, 1937. R. A. cRooK CIRCUIT BREAKER Filed March 28, 1934 3 SheeLS-Sheet 5 Rl 'L7 (VOOR Patented Apr. 13, 1937 UNITED STATES CIRCUIT BREAKER Robert Alan Crook,

Kiliala, near Sydney,

Australia Application March 28,

1934, Serial No. 717,848

In Australia April 4, 1933 2 Claims.

This invention has reference to improvements in and relating to circuit breakers of the type which are fitted with what is known generally as a free handle, and has been devised more par- 5 ticularly with the object of providing mechanical means whereby such devices may be automatically closed after having been automatically opened to relieve electrical apparatus they are intended to protect, of abnormal conditions arising in the circuit applying such apparatus.

Means for accomplishing the same object have been successfully adopted in the past, the majority of them being operated electrically; but the chief purpose of this invention is to provide me- Chanical reclcsing means capable of being manufactured at comparatively small cost and adaptable znore especially for embodiment in or application to protective devices, of the above nature.

A feature of the invention resides in the facility with which the improved apparatus may be applied to existing circuit breakers without necessity for structural alterations to the latter.

The invention contemplates the duplication and if necessary the multiplication of the aforesaid reclosing means which would be capable of being manually set, simultaneously, and adapted to operate successively so that the circuit breaker may be automatically reclosed more than once; though in modified constructions of the reclosing 0 means sufcient energy is stored in a single spring to enable the mechanism with which it is associated to repeat its function a number of times, thus enabling the one set of mechanism to effect successive reclosures of the circuit breaker.

Broadly, the invention consists in particular means7 including a spring or weight whereby energy is stored and made available automatically, through the medium of appropriate levers, for the reclosing of the circuit breaker in the event of the latter being automatically opened.

The reclosing means, the subject of this invention may be housed in a casing surrounding the circuit breaker it is intended to actuate or it may be constructed as a separate unit and situated exteriorly thereof.

The invention incorporates a time delay device which delays the operation of the reclosing means sufficiently to allow of the passing of a temporary overload in the circuit controlled by the protective device. No novelty is claimed in respect of such time delay device; it may take any of the forms commonly adopted for similar purposes.

According to one application of the invention the reclosng device comprises a spring loaded plunger housed in a cylinder supported by a rod carrying the said plunger. One end of the said rod is connected by a link to an arm of a bell crank lever mounted for operating the main shaft of the circuit breaker. The other end of the said rod is connected to one of a pair of links constituting .a toggle joint. Adjacent to this joint is situated trip mechanism incorporating a time delay device which may be in the nature of a dash-pot.

The said trip mechanism is actuated preferably by the indicator spindle of the circuit breaker and its function is to break the before-mentioned toggle joint and so allow the compressed spring to reclose the contacts of the protective device through the agency of the plunger and the bell crank lever mounted for operating the main shaft of said device.

In modified constructions of reclcsing mechanism in accordance with the present invention a wire rope or cord is substituted for the rod carrying the plunger referred to in the previous example, and said rope or cord is wrapped around a pulley capable of being rotated to compress the operating spring of the mechanism. The said pulley has associated with it trip mechanism, the respective members of which are adapted to be disengaged by means brought into operation on the automatic opening of the circuit breaker to be reclosed.

Such modified arrangement allows of a succession of reclosing operations being performed by the one mechanism, portion only of the energy stored in the spring being utilized in each such operation.

The reclosing apparatus in both of the foregoing constructions is capable of being set by hand lever or by depending means, such as a cord attached to an arm secured to thc pin on which said lever is mounted. The spring is thus compressed in readiness to reclose the circuit breaker when the aforesaid trip mechanism is actuated in the opening of said breaker.

But in order that the invention may be understood clearly and readily carried into practical effect, reference is now made to the drawings accompanying and forming part of this complete specification, and wherein are illustrated certain alternative constructions in accordance with the invention.

Figure 1 is a Somewhat diagrammatic elevational view, partly in section, serving to show the application of one form of the invention to an elevated outdoor circuit breaker.

Figure 2 is a smaller view showing in elevation the application of a modified form of the invention to a circuit breaker of the same nature as that indicated in Figure l.

Figure 3 is an enlarged elevational view of the reclosing device shown in Figure 2 with its cover plate removed to disclose its internal mechanism.

Figure 4 is a sectional elevation taken on the line 4-4 in Figure 3.

Figure 5 is a detail view drawn to a larger scale showing portion of the rear pulley seen in Figures 3 and 4.

Figure 6 is a side elevational view partly in section of a further modified form of the reclosing mechanism, this particular example having been devised for mounting on a panel on or adjacent to the operating handle of the circuit breaker.

Figure 7 is a front elevation of the mechanism illustrated by Figure 6.

The reclosing mechanism illustrated by Figure l is applied to an elevated outdoor circuit breaker 8, indicated by broken lines.

The said mechanism may be arranged as a separate unit and enclosed in a suitable casing I8, and it is operated by a spring II housed in a cylinder I2 wherein the said spring II is capable of being compressed by a plunger I3 on depression of a handle such as I4. The plunger I3 is fast on a rod I5 which at one end is connected to a link I6 attached to the arm of a bell crank lever I'I, the latter being mounted on the main shaft or free spindle I8 of the circuit breaker 8. The other end of the rod I5 is connected to one of a pair of links I9, 28, constituting a toggle joint.

Adjacent to the said toggle joint I9, 28, and adapted to break it, is trip mechanism comprising a lever 2| connected by a link 22 to one end of a lever 23 mounted resiliently on the indicator spindle 24 of the circuit breaker 8. The other end of the lever 23 carries the plunger 25 of a dash pot 26 serving as time delay means to control operation of the reclosing mechanism as hereinafter explained. The extent of the delay introduced by the dash pot 26 may be governed by adjustment of a thumb screw 21 which regulates tension of a spring 28 attached to the lever 23.

The mechanism may be furnished with means such as 29 to indicate the degree of tension in the said spring 28.

The handle I4 of the mechanism has a spring loaded rod 38 arranged longitudinally therein and this serves to engage the spindle I8 and rotate the latter when the handle I4 is moved.

Since the foregoing construction provides for one reclosing operation only, in cases where it is. desired to provide for a succession of such operations the mechanism may be duplicated, the respective sets of mechanism being arranged side by side and all capable of rotating the spindle I8 to reclose the breaker. In such cases a member such as 3| would be provided for each of the mechanisms to release the respective rod 38 immediately the handle I4 has been raised automatically in the reclosing of the circuit breaker.

In use the reclosing mechanism is set for operation as follows:-

Assuming the circuit breaker to be closed, the handle I4 is pulled down into the position shown in Figure l thereby compressing the spring I I and bringing the links I9 and 28 into alignment.

Immediately the circuit breaker 8 opens to relieve the circuit in which it is connected of an overload, the indicator spindle 24 is rotated partly as ordinarily allowing the spring 28 to rotate the lever 23 until the latter positively engages the spindle 24 when the link 22 actuates the lever 2I thereby breaking the toggle joint I9-28.

On breaking of the toggle joint consisting of the links I9 and 28 the spring I I is allowed to expend its energy by pushing the rod I5 lengthwise in the cylinder, and through the medium of link I6, bell crank lever I 'I and rod 38 causing the spindle I 8 to rotate and reclose the circuit breaker.

The dash pot 26 serves to restrain movement of the trip lever 2 I for a sufficient length of time to allow of the passing of the overload, should it be of a temporary nature, before the circuit breaker is again closed.

The mechanism may be set for repeating the reclosing operation by again depressing the handle I 4.

'I'he reclosing mechanism illustrated by Figures 2 to 5 inclusive is intended to be mounted on the front wall or cover plate of the circuit breaker 8 as in the previous example, but in this case is capable of performing a succession of reclosing operations.

The mechanism according to this modification of the invention is mounted in a casing such as I8 and the cylinder I2 for the operating spring I I extends upwards at an angle to the horizontal.

The energy of the spring I I in this construction is transmitted through the medium of a wire rope or cord 32, to a pulley 33 rotatable with a spindle 34 carrying a handle I4.

The free spindle I8 of the circuit breaker in this case has fast on it a member 35 wherein is a radially disposed slot 36 which accommodates a pin 3l. The said pin is carried by a plate 38 (see Figure 5) which is pivoted to the member 35, the said plate 38 being furnished with a spring 39 normally to retain the said pin 3'I in` the bottom of the slot 36. An adjustable spring 48, anchored to the bottom of casing I8 normally tends to rotate the member 35 in an anti-clockwise direction.

The forward end of the pin 3l has a fiat portion 4I formed on it and said pin engages the teeth of a ratchet Wheel 42 which is carried concentrically on the face of the pulley 33.

A spring loaded pawl 43 is pivoted alongside the ratchet wheel 42 to serve as a detent for the latter, and is designed to retain temporarily energy imparted to the spring I I.

The trip mechanism in this construction of the invention is actuated by the indicator spindle 24 as in the previous example, and in this case consists in a bell crank lever 23 mounted on said spindle 24 and adapted to transmit its movement to the pin 31 through the medium of a horizontal push rod 44, a thrust ball 45 and a Vertical push rod 46. An adjustable leaf spring 4l on the face of the bell crank lever 23 serves as a buffer.

The rear end of the pin 3l is wedge shaped as indicated by the broken lines 48, in Figures 3 and 4, for engagement with pins or studs 49 which project from the face of a smaller pulley 58 situated at the rear of the mechanism, and adapted to receive a belt 5I from time delay means 52 which in this instance is of the clockwork escapement type. This, as is clear from Figs. 3 and 5, retards the movement of the pin 31 about the ratchet wheel 42.

A bar 53 secured rigidly to the Wall of the casing I8 serves as a stop or abutment for the member 35, and there is another bar 54 which is pivoted to the wall of the casing I8, serving as a locking device for the whole mechanism. This second bar 54 is capable of being raised into and held in engagement with a lip formed on the lil bottom of member 35, by means of a cam 55 on the upper end of a spindle 56 to which, below the bottom of the casing I0, is affixed a handle 51.

The modied form of the invention just described is set for reclosing operations by turning the handle I4 in an anti-clockwise direction to compress the spring II in the cylinder I2 as in the previous construction.

The ratchet wheel 42 being secured to the pulley 33, is rotated on the turning of the handle I4 and is prevented from rotating in the reverse direction by the pawl 43.

Immediately the circuit breaker opens, the lever 23 is moved by the indicator spindle 24 and forces the push rod 44 against the ball 45 which in turn raises the short push rod 46 and lifts the pin 31 out of engagement with the ratchet wheel 42. Such movement leaves said pin free to rotate with member 35 in an anticlockwise direction under the influence of spring 4G. As the pin 31 is raised from engagement with ratchet wheel 42 the wedge shaped rear portion of the former engages with the pins or studs 49 on pulley 50 and causes the latter to be rotated to drive the time delay mechanism 52. rIhe mechanism 52 serves in known. manner to delay movement of the pin 31 in its passage around the wheel 42, so that the pawl 43 will not be disengaged from said wheel 42 until an appropriate interval has elapsed.

As the pin 31 approaches the next tooth on the ratchet wheel 42 it is returned by spring 39 to the bottom of slot 3S thus releasing the time deiay mechanism. The at portion 4I of said pin 31 then comes into contact with the pawl 43 and dislodging the latter allows the pulley 33 with the ratchet wheel 42 to be rotated in a clockwise direction carrying with it the pin 31 and member 35 and thereby turning the free spindle I8 of the circuit breaker to reclose the latter device. The pawl 43 then engaging the ratchet wheel 42, and the stop 53 engaging member 35 further clockwise movement of these members is prevented until the next reclosing operation.

Further reclosing operations may automatically be eiected by the mechanism until the energy stored in the spring I I has been exhausted.

The modied form of the invention illustrated by Figures 6 and 7 has been devised for mounting on a panel carrying the circuit breaker and is adapted to move the existing handle of the latter device.

In this example oi the invention the reclosing mechanism is capable of being set for operation by turning a handle or pulley mounted on a spindle 58 whereby aspur wheel 59 carrying pulley 33 and ratchet wheel 42 are rotated to compress the spring il. The spur wheel 59 is in engagement with a pinion 65 associated with which are a pair of slotted crank discs 5I operating connecting rods 62 attached to the existing free handle 63 of the circuit breaker.

On the opening of the circuit breaker, push rod 54 is raised by the usual latch which the free handle engages and said rod 64 then moves a bell crank lever 65 and so releases temporarily the ratchet wheel 42 allowing spring il to rotate the spindle 55 and cause the handle S3 to be again depressed to close the circuit breaker.

The time delay device 52 serves to delay the upward movement of the handle 63 and is disengaged on commencement of the downward movement of said handle.

It will be obvious that in all the examples illustrating the application of this invention herein described, a suspended weight may be employed instead of the spring II for the storing or" energy required to perform the reclosing operations.

I claim:

l. Mechanism for automatically reclosing circuit breakers or" the free handle type having a spindle, comprising a casing; means on said casing whereby the latter is supported on or adjacent to the front wall of a circuit breaker; mechanism in said casing including a compressible spring; a spindle mounted coaxially with the spindle of the circuit breaker whereon the free handle normally is secured, a pulley fast on said co-axially mounted spindle, a rope wound around said pulley whereby the said spring may be compressed; a handle exteriorly of the aforesaid casing and mounted on the spindle carrying the 1 said pulley to enable the latter to be rotated to compress said spring; clutch mechanism in said casing including a ratchet whe-el fast on the spindle carrying the said pulley, a member with a radially disposed slot and which iits onto the aforesaid spindle of the circuit breaker, and a holding pin in said slot engaging the said ratchet Wheel; a detent for said ratchet wheel designed to retain temporarily energy imparted to the said spring; an indicator spindle; releasing means actuated automatically by said indicator spindle and serving to disengage the said pin from the said ratchet wheel on the opening of the circuit breaker; and time delay mechanism operated by the aforesaid spindle or" the circuit breaker, whereby operation of the said reclosing mechanism is delayed until the said detent has been disengaged.

2. Mechanism for automatically reclosing circuit breakers, as claimed in claim l, wherein the said detent comprises a pawl which normally holds the ratchet wheel and the pulley with which the latter is associated, against rotation by the said spring; and wherein there is a plate pivoted Y to the said member with the radially disposed slot therein, the said pivoted plate carrying the said holding pin; and means controlled by the usual indicating spindle of the circuit breaker, and including push rods and a ball whereby the said pin is released temporarily from engagement with the aforesaid ratchet wheel when the circuit breaker opens.

ROBERT ALAN CROOK.

Images