US2091941A - Circuit breaker - Google Patents

Description

-2 Sheets-Sheet 1 w. H. FRANK CIRCUIT BREAKER original Fileduarcn s, 1935 ATTORNEY.

Aug. 31, 1937;

Aug. 3l, 1937. w.- H. FRANK QIRCUIT'BREAKER Original Filed March 6, 1933 2 sheets-Sheet 2 E o x.

v ATTORNEY.

Patented Aug. 3l, 1937 `PATENT .OFFICE cmcm'r a wiunnn n.

Frank, Detroit. Bulldog Electric Products Mich., allignor to Company, Detroit,

Mich., a corporation of Welt Vllllnia Original application March 6, 1933, Serial No.

Divided and this application January 9, 1936, Serial No. 53,440

8 Claims. (Cl. 20G-116) This application relates to circuit breakers, and is a division of a prior application, Serial No. 659,714, led March 6, 1933.

In that application there is disclosed a breaker s having a link' 24 normally held anchored at one end by a thermal latch I4 and movable by means of a handle 42 over the center of rotation 43 of the handle for make and break action; the mechanism is such that movement of the free end 31 l of the link away from a spring abutment 23 thereon determines the degree of ilexure of the operating spring 21 of the breaker. In that application, the over-center arrangement of the parts is utilized and the free end 31 of the link 15 24 is arranged to move circularly only, around the center 43 of the handle 42.

'Ihe principal object of the present invention is to provide, in a construction generally similar to that of application Serial No. 659,714, an arrangement of parts providing a separation of link end 3l from spring abutment 29 much greater than that which is possible in the construction of application Serial No. 659,714. This object is attained by replacing the over-center arrange- 25 ment of the parts as shown in application Serial No. 659,714 with an arrangement disclosed herein, one employing a hill and valley path for the link end 31,`the path being such that link end 31 will move radially of the handle center 43 on n breaker operation, as well as circularly, with the result that link end 31 will move away from abutment 29 a distance much greater than is the case when link end 31 can move circularly only, about 85 'center 43. e

The hill and valley path hereof, as contradistinguished lfrom that of application Serial No. 58,439, niedfqanuary 9, 1936 which discloses a breaker-resembling that of this case, ls formed o on the crank or handle of the breaker, rather than on the frame. Consequently, rotation of the handle until the link end 31 climbs over the hill does not cause rotation of link 24 about its and does not cause movea ment of the contact linkage connected thereto, and therefore there is no necessity for providing lost motion between the contact and the link 24, all as is necessary in the construction of application Serial No. 58,439. Because/of theabsence I of lost motion between the/contact and the link 24, it is desirable to employ "kickers" on the handleuor crank for initiating movement oi' the contact parts out of "on and on positions.

u -Other characteristics of the breaker herein disosed will readilyI occur to the skilled in the vplate 2i.

art upon reference to the following description and the accompanying drawings, in which Fiss. 1, 3, and 4 are elevation views of a breaker in "on, olf, and overload off" positions, respectively; 5

Fig. 2 shows the breaker in left end view.

The breaker includes a base I0 having a pair of contacts II which are to be engaged by the contacts I2 on the ends of a resilient bridging contact arm I3. One of the contacts I I is connected to the line and the other is connected to one leg of the thermostatic or bimetallic warping element I4, the other leg of the latter being connected to the load. When the contact arm I3 is in on position, current ows through contacts lI and I2, contact arm I3, and warping element I4.

To the vertically moving contact arm I3 is rigidly secured an upwardly projecting sliding link Is. A link z2 is pivotauy connected at n 20 to a horizontal link 24 and is also pivotally connected to the upper end of the link I5 through a pin 23. A coil compression resisting spring 21 is mounted on the right hand end of link 24 between a pin n thereon and the bight of a u- 25 shaped horizontally positioned spring compression link 23, which is pivotally connected at 3l to a pawl 32, the latter being pivotally connected by shouldered screws 33 on its left end to front As indicated, the link 24 passes through 30 a slot in the bight of link 23 and these links move as a unit around the pivot 3l. In the "on position the right hand or free end 35 of pawl 32 is held down by a tongue 33 of warping element I4. 85 The left hand end 31 of link 24 is pivotally connected to an operating bell crank 3l by a pin 39 sliding in a. slot 4Ia of the crank. The bellcrank has an extension `42 forming an operating handle for the device, and is pivotally supported o on the cross shaft 43 mounted in the front yplate 2|.

The slot 4Ia la formed as a hill and valley slot whose valleys are referenced V-V and whose Ahill is referenced H, the inner edge thereof forming a hill and valley riding path for the pin 33 a of link end 31; the hill is radially more remote from pin 3l than are the valleys.

'I'he parts just described may be operated as a simple, quick make and break switch as follows: Assume the parts to be in on position, Figure l.

When the handle 42 is moved to the left, the bell crank 33 rotates counter-clockwise, forcing end 31 of link 24 to slide radially of center 43 towards the left a slight degree and build up an u increased compression in coiled spring 21. All

this while, link end 31 does not move circularly about center 43, and the contact linkage 22-I5 does not move.

As soon as the end 31 of link 24 has passed 5 over the hill H, the coil spring 21 operates with a snap action to cause link end 31 to ride up in slot 4Ia from H to V, thus pulling contact arm I3 to its off position for quick break.

Reverse movement of handle 42, to the right from the oi position, Fig. 3, imparts a sliding movement to link 24 away from pin 3I to compress spring 21 until the end 31 of link 24 is past hill H, and during such movement contact linkage I5-22 does not move. When the end 31 of l5 link 24 passes over the hill H, spring 21 expands to snap the parts, and the contact arm I3, to circuit closing position.

Slot 4Ia permits snap action movement of the links 24 and 29 independent of the handlev 42 so that quick make and break are independent and free of the operator. break are assured by the positive connection between'crank 38 and link 24, namely pin 39 and slot 4Ia, previously described. Termination of 25 movement is provided by the engagement of crank pin 24I with either end of frame slot 242.

During normal switch operation travel of pawl 32 about its pivot 33 is prevented by its end 35 being held by the anchorage tongue 36 of warping element I4.

It will be observed that kickers 243-244 engage the pin 23 simultaneously with the alinement of hill H with link end 31 to kick the contact linkage out of its rest position and to kick 35 link end 31 over the hill, in the event such auxiliary action is required. The provision of these kickers also insures positive make and break.

In overload release action, pawl 32, when released (Fig. 4) by the thermal element, moves upwardly with a spring action, screws 33 serving as xed pivots', and in so moving, pawl 32 causes link 24 to move up so that the later pulls up on links 22-I 5 for a quick overload break.

Part of the upward travel of pawl 32 is unrestrained or free of the crank 38 (for trip free action) and this part is sumcient to cause contacts I2 to leave contacts II, and effectively rupture the circuit. On the last part of the upwardl travel of pawl 32, the pin 23 engages kicker 243 and moves crank 38 from on position to overload "oi position, this feature providing an overload oi indicating position to the handle, it

being observed that overload oi position is between the on" position and the normal ,of POSOD.

During the overload release movement, link end 31 moves upwardly to provide a greater movement of link 24 and a larger break on overload release, than would be the case were the left end of link 24 to remain fixed.

For reset, handle 42 is rotated counter-clockwise to ci position so that cam crank 38 engages rollers 246 of pawl 32, moving these down in slots 241 of plates 2I-2Ia, and

6 consequently moving the pawl down, resetting the same. Y

The left end 31. of link 24 in the meantime moves further out of on position towards off position, the timing of this movement being such 70 that the link 24 assumes its off positionprior to the time that pawl 32 is reset to its latched position, this insuring against circuit closing during the resetting movement.

New having described the breaker herein dis- :.5 closed, reference should be had to the claims Positive make andedge 245 `of which follow for al determination oi the monopoly sought herein.

l. In a circuit breaker, an operating mechanism including a pivotally mounted link, and a link mounted to slide lengthwise through a part of said rst mentioned link and to move therewith about the pivot thereof, a coiled spring on the second link reacting between an abutment thereon and the aforementioned part of the rst link, a bell crank pivotally mounted on its fixed pivot and having one branch formed to provide a handle and another branch pivotally connected to an end of the second link, and means on the bell crank for causing such end to move radially of the bell crank pivot as well as circularly around the latter when the bell crank is rotated.

2. In a circuit breaker, an operating mechanism including a pivotally mounted link, and a link mounted to slide lengthwise through a part of said first mentioned link and to move therewith about the pivot thereof, a coiled spring on the second link reacting between an abutment lthereon and the aforementioned part of the first` link, a bell crank pivotally mounted on its fixed pivot and having one branch formed to provide a handle and another branch pivotally connected to an end of the second link, and means causing such end to move radially of the bell crank pivot as well as circularly around the latter when the bell crank is rotated, the pivotal connection between the link end and the bell crank comprising a pin and slot connection whereof the slot permits the pin to move circularly of and radially with respect to the bell crank pivot.

3. In a circuit breaker, an operating mechanism including a pivotally mounted link, and a link mounted to slide lengthwise through a part of said rst mentioned link and to move therewith about the pivot thereof, a coiled spring on the second link reacting between an abutment thereon and the aforementioned part of the first link, a bell crank pivotally mounted on its fixed pivot and having one branch formed to provide a handle and another branch pivotally connected to an end of the second link, and means causing such end to move radially of the bell crank pivot as well as circularly around the latter when the bell crank is rotated, the pivotal connection between the link end and the bell crank comprising a pin and slot connection whereof the slot causes the pin to move circularly of and radially with respect to the bell crank pivot.

4. In a circuit breaker, an operating mechanism including a pivotally mounted link, and a link mounted to slide lengthwise through a part of said first mentioned link and to move therewith about the pivot thereof, a coiled spring on the second link reacting between an abutment thereon and the aforementioned part of the first link, a bell crank pivotally mounted on its xed pivot and having one branch formed to provide a handle and another branch pivotally connected to an end of the second link, and means causing such end to move radially-of the bell crank pivot as well as circularly around the latter when the bell crank is rotated, the arrangement of the parts being such that initial movement of the bell crank causes the second'link to slide lengthwise and stress the spring, without rotating the link substantially about its pivot, until a critical position of the link and bell crank is reached,

whereupon the link is caused to shift .about its.

to cause quick contact movement free of the bell crank` 5. In a circuit breaker, an operating mechanism including a pivotally mounted link, and a with about the pivot thereof,

second link reacting between an abutment thereon and the aforementioned part of the first link, a bell crank pivotally mounted on its fixed pivot and having one branch formed to provide a handle and another branch pivotally connected to an end of the second link. and means causing such end to move radially ol' the bell crank pivot as well ascircularly around the latter when the bell` crank is rotated, the pivotal connection between the link end and the bell crank comprising a pin and slot connection whereof the slot causes the pin to move circularly oi' and radially with respect to the bell crank pivot, the arrangement of the partsv being such that initial moveabout its pivot suddenly by the stressed spring,

one position and positioned to be stressed by and on movement of the link out of'that position and to move the link with a snap I handle, the spring being so positioned that it is stressed more by radial and circular movement of the link than by circular movement thereof 50 alone.

- snap action, the parts being so tially out of the ilrst position and towards such other portion by the handle, and means on the handle for guiding the link, in its movement. so that it slides radially of the handle pivot when it is moved circularly about the handle pivot by the handle, the spring being so positioned that it is stressed more by radial and circular movement of the link than by circular movement thereof alone, the pivotal mounting for the link being automatically releasable on a circuit abnormality to release the link and permit the spring to move it about its pivotal connection to the handle for circuit interruption.

8. In a circuit breaker controlling mechanism, a resilient mechanism, a movable current responsive latch so constructed and arranged that it normally engages the mechanism for holding it, the parts being so arranged relatively that the mechanism, when held by the latch, is under longitudinal stress, the latch being movable on a circuit abnormality i'or releasing the mechanism, a rotatably mounted handle, means operatively connecting it to the mechanism, the handle being so constructed and arranged that on rotary movement thereof out of its normal position it will stress the mechanism longitudinally and move it bodily out of its normal position and towards the center of rotation of the handle so that when the handle is released after such movement the mechanism will tend to relieve itself of the longitudinal stress created therein by such movement of the handle with a arranged relatively that on such stress relieving movement of the mechanism following such handle movement and subsequent release, the mechanism will move bodily beyond the center of rotation of the handie and about the connection between the mechanism and latch as a, pivot, and also being so arranged relatively that on release of the latch, when the handle and mechanism are in normal position, the mechanism will tend to relieve itself of the stress that'it possesses when it is held by the latch with a snap action and in so doing will move bodily about its connection to the handie as a pivot, the resilient mechanism, the handle. and the latch being so arranged and constructed and relatively connected that the handle connection end of the resilient mechanismmoves radially of the handle center of rotation a considerable extent as well as circularly thereof when the handle is rotated to rotate the resilient mechanism about its latch connection end, there being at the handle connection end of the resilient A mechanism a hill and valley means providing a hill and valley path for the handle connection end of the spring means, the path itself being l in the nature of a slot formed in the handle of the device.

WILLIAM H. FRANK.

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