US3183325A

US3183325A - Trip indicating circuit breakers

Info

Publication number: US3183325A
Application number: US107401A
Authority: US
Inventors: Alexander R Norden
Original assignee: Federal Pacific Electric Co
Current assignee: Federal Pacific Electric Co
Priority date: 1961-05-03
Filing date: 1961-05-03
Publication date: 1965-05-11
Anticipated expiration: 1982-05-11
Also published as: DE1855160U; GB953773A

Description

May 11, 1965 A. R. NORDEN TRIP INDICA'I'ING CIRCUIT BREAKERS 2 Sheets-Sheet 1 Filed May 3. 1961 INVENTOR. ALEXANDER R. NORDEN r I I-I- LL- I (1:)

I gy

ATTORNEY May 11, 1965 A. R. NORDEN TRIP INDICATING CIRCUIT BREAKERS 2 Sheets-Sheet 2 Filed May 3. 1961 FIG.8

FIG. 7

INVENTOR. ALEXANDER R. NORDEN ATTORNEY United States Patent 3,183,325 TRIP INDICATING CIRCUIT BREAKERS Alexander R. Norden, New York, N.Y., assignor to Federal Pacific Electric Company, a corporation of Delaware Filed May 3, 1961, Ser. No. 107,401 Claims. (Cl. 200-116) This invention relates to circuit breakers and more particularly to circuit breakers provided with means for indicating that the breaker has operated in response to an overload.

In some circuit breaker applications as in panelboards employing a large number of breakers mounted in sideby-side relation, some of which are off while others are on, it is desirable to have a trip indicating position so that automatically tripped circuit breakers may be readily distinguished from those which have been turned off manually. Ideally, the tripped position should be obtainable only when the breaker is opened automatically to preclude false indication of circuit problems. Additionally the mechanism for providing the desired indication should not interfere with the normal on-oil operation of the breaker. It is an object of this invention to provide circuit breakers having the aforedescribed desired properties.

It is another object of this invention to provide a simple, relatively low cost, circuit breaker having a trip-indicating handle position.

It is another object of this invention to provide a novel circuit breaker wherein indicia which normally indicate either on or off are obscured in the tripped position of the handle.

A well-known and widely used form of circuit breaker involves a mechanism having a pivoted contact arm that includes a handle-operated toggle to close this circuit breaker, acting through an overcurrent controlled latch in the closing operation and thus being trip-free. Such a circuit breaker is shown, for example, in US. Patent No. 2,681,396, assigned to the same assignee as the present application. It is a characteristic feature of such circuit breakers that, upon overcurrent release, the handle is restored to the off position automatically when the contacts are driven open. This places the operating mechanism in immediate condition for reclosing the breaker, but it does not provide a trip indication.

A specific, yet important, object of this invention resides in the provision of a novel circuit breaker of this type, improved to provide trip indication.

The foregoing objects are achieved in the illustrative embodiment of. the invention described in detail below.

This illustrative circuit breaker has a pair of companion contacts, one of the contacts being mounted on a contact arm pivoted intermediate its ends. An actuator, pivoted to the opposite end of the contact arm, has a latching portion at one end which cooperates with an overcurrentresponsive latch that is also carried by the contact arm. The operating handle of the circuit breaker has a mechanicaldink connection to the contact arm for closing the contacts and for holding the contacts closed, this being effective so long as the actuator is latched. A restoring spring tends to restore the operating means upon release casing being removed, and the circuit breaker being in its circuit making condition;

FIG. 2 is a similar view showing the circuit breaker of FIG. 1 in the open circuit position;

FIG. 3 is a similar view showing the circuit breaker of FIGS. 1 and 2 in the tripped position;

FIG. 4 is a view similar to FIG. 1, and illustrates another embodiment of the present invention as applied to multi-pole circuit breakers;

FIG. 5 is a fragmentary top view of the device in FIG. 3 as seen from the line 55 therein;

FIG. 6 is a fragmentary View of the device in FIG. 1, showing parts in solid and broken lines to represent two different conditions;

FIG. 7 is a fragmentary cross-sectional view taken along the line 7-7 of FIG. 6;

FIG. 8 is a view similar to FIG. 7 with the parts shown in the condition of the breaker represented by FIG. 2; and

FIG. 9 is a fragmentary view similar to FIG. 6 of yet another embodiment of the invention.

Referring now to the drawings in detail, the various circuit breakers which illustrate the various embodiments of the present invention each comprises a two-part casing of insulation having complementary molded parts in which the terminals 10 and 12 and circuit breaker mechanism are mounted as described, for example, in US. Patent 2,681,396.

Movable contact 16 is carried by the Contact arm 18, and'a companion stationary contact 14 is fixed to terminal member 10. The movable contact arm 18 is pivotally mounted on spring 2i? (FIGS. 7 and 8). The circuit breaker is operated manually from open position (FIG.

'2) to closed position (FIG. 1) by the operating means 22. This includes the handle 24, an actuator 26, and a connecting link 28. Link 28 is pivoted at one end to handle lug 3t? and at its opposite end link 23 has a pivot 32 in the actuator 26. The handle is pivoted in the front and rear walls of the casing. Actuator 26 has a pivot 34 on the movable contact member 18. The actuator 26 is operatively connected to the movable contact member 18 for driving the latter in the closing direction under the control of the current-responsive latch 36. As here shown the current-responsive latch includes a bi-metallic strip 38 that is fixed to movable contact member 18 adjacent to contact 16, and the current-responsive latch also includes a pole 40 of magnetic material for electromagnetically deflecting the bimetal downward on sudden severe overload-current in the bimetal.

Considering FIG. 2, the operating means 22 includes the handle 24 and link 28 which constitute an actuating toggle for driving the circuit breaker closed. Initially this driving toggle forces the lower end of actuator 26 against the end of bimetal 38. Thereafter

elements

26, 38 and 18 function as a unit, and are operated clockwise about pivot spring 20 as the

toggle

28, 30 progressively becomes straight and somewhat overcentered. It is arrested in slightly overcentered condition by engagement of the handle 24 with the edge of the handle opening in the casing.

The operating means of the circuit breaker includes restoring means 42 which includes a compression spring 44 that engages lug 46 on the handle and lug 48 on the contact arm 18. The spring 44 biases both the movable contact arm 18 and the handle 24 toward their respective open positions. Spring 44 applies its full force to contact arm 18 in a counterclockwise direction about pivot 20, at a relatively long radius. Spring 44 also acts almost along a line through the handle pivot so as to apply only a component of its clockwise biasing force on the handle, and the spring force is applied to the handle at a comparatively short radius.

A portion 5%) projects from the upper edge of contact arm 18 intermediate the pivot 2'1 and the actuator 26. This projection Ed is included to impart the trip-indicating characteristic, as will be clear from the description of the operation of the circuit breaker.

Circuit breaker operation may now be described. The circuit breaker is shown open in FIG. 2. Handle lever 69 is moved counterclockwise to drive operating toggle 28, 3t), actuator 2s and contact arm 18 into the configuration in FIG. 1. In this configuration of the parts, the operating toggle subjects spring 2t) to downward deflection into tapered recesses 63 in the casing as represented in FIG. 7. Spring 2% thus biases contact arm 18 clockwise about pivot 34 so that'firm contact pressure is developed. This pressure is maintained despite travel of toggle 28, 3!) past dead-center into the locked condition of FIG. 1, so that spring Zll also acts as an overtravel spring.

Link 28 and the actuator 26 constitute an overload release toggle, with its knee 34 slightly off-center. Bimetal 38 is deflected downward in response to an overcurrent through the circuit breaker. Actuator 26 is then released and the elements 13, 26 and 2d quickly move to the broken-line configuration in FIG. 6 under powerful impetus of spring Ztl. The nearly

straight release toggle

28, 26 is now prominently buckled. Push-off spring 44 becomes effective at this stage to drive contact arm 18 counterclockwise about its pivot 2h, thus opening the contacts. This involves continued upward travel of projection Silt. Spring 44 is also elfective to drive the handle 24- clockwise from the on position in PEG. 1.

Projection 5% reaches an interfering position in the return motion of handle lug 3t? when actuator 26 has its latch portion above bimetal 33, as shown in broken lines in FIG. 6 and as shown in FIG. 3. As shown in this figure, lever 6d of the handle is arrested midway between the on and on position of FIGS. 1 and 2. This handle position provides an indication that the circuit breaker was automatically released.

For closing the circuit breaker after an automatic opening operation, handle 24 is forced from its tripindicating position (FIG. 3) to its off position (FIG. 2). In this motion, lug 3d cams projection Stl out of its path, and link 28 restores the lower end of actuator 26 to the position shown in FIG. 2 in readiness for closing opera tion of handle 24.

Projection 50 does not interfere with manual movement of the handle 24 to the off position because link 28 maintains suiticient separation between contact arm 18 and handle lug 3% when actuator 26 is latched. By

like token, projection 54} is maintained out of the contact closing motion of handle lug 30.

FIG. 9 illustrates another embodiment of the invention. The parts and their operation are like that already described, except that a rigid pivot 7% supports the contact arm, and except that contact pressure and overtravel are provided by the resiliently mounted companion contact 72. The initial impetus for moving the arm 18 in response to overcurrent release of actuator 26 is derived from the contact pressure spring '74 which reacts between the contact 72 and the casing. Contact pressure spring 74 is primarily responsible for the high speed initial movement of the arm. 18 from the solid to the dotted line position shown in FIG. 9. Continued movement of arm 13 about pivot '74 is produced by the direct action of the restoring spring 44 as in the previously described embodiment. Projection 50 again reaches its interfering position prior to the arrival of the handle lug 30. Referring to FIG. 4 there is illustrated yet another aspect of the invention, applied to a multi-pole circuit breaker of the type shown and described in US.

Patent 2,923,795 which is assigned to the same assignee as the present application. Primed numerals are used in FIG. 4 corresponding to those in FIG. 1. In multipole breakers of this type, the signal link 28 of FIG. 1

AK is replaced by a multi-pole release toggle 28. This includes an intermediate link 62, (common to all the poles of the multi-pole circuit breaker) and an individual link as for each pole. Link as is provided with a lug 64. in the closing operation of the circuit breaker, toggle 28' is rigid, links s2 and 66 are straight, and the other aspects of the closing operation are just as described in connection with FIGS. 13. In this breaker, however, the lug s4 (rather than handle lug St!) is engaged by the projection 50' formed on the contact arm 18 when the ac tuator 26 has been released by operation of the latch 36. The engagement of the lug 6d and projection 50 causes the handle 24 to assume the central, trip-indicating position under the influence of the restoring means 42. The projection St) is driven to the interfering position in the return path of lug 64 by the contact pressure spring 20'.

'Referring to FIG. 5, a handle 24 is illustrated which is typical of the handles employed in all the aforedescribed embodiments. tT he hub of the handle is provided with two sets of indicia '52 and 54, which indicate the closed condition of the contacts i.e. "on andthe open condition of the contacts off, respectively. A portion till of the handle 24- protrudes through an opening 56 in the casing. In the respective on and off conditions of the breaker the opposite indicia is disposed beneath the overlying portions 538 of the casing. In the tripped condition of the breaker, wherein the projection 50 arrests the lug 39 of the handle, the on and the

off indicia

52 and 54 are both simultaneously obscured by portions 58 of the casing with the lever portion as of the handle in an intermediate position.

Although several embodiments of the invention have been shown and described, it will be apparent that various changes and modifications may be made therein by those skilled in the art. Consequently, the invention should be broadly construed in accordance with its full spirit and scope.

What I claim is:

1. In a circuit breaker, a pair of companion contacts, a contact arm pivoted between is ends and having one of said companion contacts at one end, an actuator pivoted to the opposite end of said contact arm and having at one end thereof a latching portion, an overcurrent latchw ing device carried by said contact arm and disposed normally as an obstruction in the path of said latching portion, and operating mechanism for opening and closing the contacts including a handle and including means for restoring said contacts to their open position upon release of said actuator by said overcurrent latching deioe, said contact arm and said operating mechanism having mutually obstructing means in the restoring paths thereof immediately after release of said actuator, said ohstructing means being effective to arrest the handle in a partially restored trip-indicating position.

2. A circuit breaker comprising a movable contact and a companion contact, a contact arm pivoted between its ends and carrying said movable contact at one end, an actuator pivoted to the opposite end of said contact arm and having at one end thereof a latching portion, an overcurrent latching device mounted on said contact arm adjacent to said movable contact and extending toward said latching device and disposed normally as an obstruction in the path of said latching portion, and operating mechanism for opening and closing the contacts, said mechanism including a handle and including means for operating said contact arm and the remainder of said mechanism so as to open the contacts upon release of said actuator by said overcurrent latching device, said contact arm having a portion fixedly carried thereby and projecting into the path of a portion of said operating mechanism in the return motion of said operating mechanism produced by said restoring means following release of said actuator so as to arrest the handle in a trip-indicating position, v, l

3. A trip-indicating circuit breaker including a movable contact and a companion contact, a contact arm pivoted between its ends and carrying said movable contact at one end, an actuator pivoted to the opposite end of said contact arm and having at one end thereof a latching portion, an overcurrent latching device carried by said contact arm and disposed normally as an obstruction in the path of said latching portion, and operating mechanism for opening and closing the contacts including a pivoted handle and link means connecting said pivoted handle to a portion of said actuator, restoring spring means acting against said handle and against said contact arm, said contact arm having an integral obstruction projecting into the path of a portion of said operating mechanism during the return motion of said operating mechanism in the released condition of said actuator, said restoring spring means being arranged to move said contact arm upon release of said actuator so that said projecting portion of the contact arm is in said path prior to the return of said projecting port-ion of said openating mechanism past said projecting contact-arm portion.

4. A trip-indicating circuit breaker including a movable contact and a companion contact, a contact arm pivoted between its ends and having said movable contact at one end, an actuator pivoted to the opposite end of said contact arm and having at one end thereof a latching portion, an overcurrent latching device carried by said contact arm and disposed normally as an obstruction in the path of said latching portion, and operating mechanism for opening and closing the contacts including a pivoted handle and link means connecting said pivoted handle to a portion of said actuator, restoring spring means for said pivoted handle and for said contact arm, and said contact arm having an integral obstruction projecting into the return path of a portion of said operating mechanism and said portion being operated into said return path by said restoring spring means prior to the return motion of said portion of said operating mechanism past said projecting contact-arm portion in the released condition of said actuator.

5. A trip-indicating circuit breaker including a movable contact, a companion contact, a contact arm pivoted between its ends and having said movable contact at one end, an actuator pivoted to the opposite end of said contact arm and having at one end thereof a latching portion, an overcurrent latching device carried by said contact arm and disposed normally as an obstruction in the path of said latching portion, and operating mechanism for opening and closing the contacts including a pivoted handle and link means connecting said pivoted handle to a portion of said actuator, a restoring spring between said handle and said contact arm, said contact arm having an integral obstruction projecting into/the return path of an integral obstruction of said handle when said arm and said handle are moved in the restoring direction by said restoring spring upon release of said actuator.

6. A trip-indicating circuit breaker, including a movable contact, a companion contact, a contact arm pivoted between its ends and having said movable cont-act atone end, an actuator pivoted to the opposite end of said contact arm and having at one end thereof a latching portion, an overcurrent latching device carried by said contact arm and disposed normally as an obstruction in the path of said latching portion, and contact operating mechanism for opening and closing the contacts including a. pivoted handle having a lug, link means connecting said lug to said actuator, and restoring means tor said contact arm and said handle, said restoring means including a restoring spring acting oppositely against both said handle and said contact arm in their respective restoring direction-s and spring means biasing one contact against the other in their closed condition, said contact arm having a discrete projection between said actuator and said pivot, said projection being disposed in the return path of said lug when said actuator is released.

7. A trip-indicating circuit breaker including a casing, a movable contact, a companion contact, a contact carrier pivoted between its ends in said casing and havin said movable contact at one end, an actuator pivoted to the opposite end of said contact arm and having at one end thereof a latching portion, an overcurrent latching device carried by said contact arm and disposed normally as an obstruction in the path of said latching portion, and a contact operating mechanism tor opening and closing the contacts including a pivoted handle having a hub and a lever portion projecting through an opening in said casing, indicia indicating the normal conditions of said breaker disposed on said hub on oppoiste sides of said lever, portions of said casing obscuring respective ones of said indicia in either of the normal conditions of said breaker, link means connecting said pivoted handle to a portion of said actuator, a restoring spring reacting between said pivoted handle and said contact arm, said contact arm having a projection fixed thereto and disposed in the return path of a portion of said operating mechanism produced by said restoring spring in the released condition of said actuator, said pivoted handle then being arrested with said two indicia obscured by said casing.

8. A trip-indicating circuit breaker including a movable contact, a companion contact, a contact arm pivoted between its ends and having said movable contact at one end, an actuator pivoted to the opposite end of said contact arm and having at one end thereof a latching portion, an overcurrent latching device carried by said contact arm and disposed normally as an obstruction in the path of said latching portion, an actuating toggle for driving the contacts closed, said toggle including a pivoted handle forming one toggle link and a connecting toggle link between said handle and said actuator, restoring spring means acting against said handle and against said contact arm, said contact arm having a projecting obstruction disposed in the return path of a portion of one of said toggle links in the released condition of said actuator.

9. A trip-indicating circuit breaker in accordance with claim 3 wherein said contact arm has a helical coil spring constituting a pivot and wherein said operating mechanism subjects said spring pivot to stress when said contacts are closed, said spring pivot being efl'Tect-ive quickly upon release of said actuator by said latching device to shift said projecting obstruction of the contact arm into the return path of a portion of said mechanism, as aforesaid.

10. A trip-indicating circuit breaker in accordance with claim 3 wherein said companion contact has a spring biasing said companion contact toward said movable contact, said spring being eflective to provide initial impetus of the contact arm in the contact opening direction, upon release of said actuator by said overcurrent latching device for effecting rapid restoration of the contact arm and shift of said projecting obstruction into the return path of a portion of said link means as aforesaid prior to restoration of said operating mechanism.

References Cited by the Examiner UNITED STATES PATENTS 1,967,890 7/34 Kuhn 200-116 2,693,513 11/54 Cellerini et al 200-116 2,806,103 9/57 Gelzheiser 200-116 2,811,605 10/57 Christensen et al 200-116 2,828,388 3/ 58 Christensen et a1. 200-116 2,887,548 5/59 Middendorf 200-116 BERNARD A. GILHEANY, Primary Examiner.

Claims

1. IN A CIRCUIT BREAKER, A PAIR OF COMPANION CONTACTS, A CONTACT ARM PIVOTED BETWEEN ITS ENDS AND HAVING ONE OF SAID COMPANION CONTACTS AT ONE END, AN ACTUATOR PIVOTED TO THE OPPOSITE END OF SAID CONTACT ARM AND HAVING AT ONE END THEREOF A LATCHING PORTION, AN OVERCURRENT LATCHING DEVICE CARRIED BY SAID CONTACT ARM AND DISPOSED NORMALLY AS AN OBSTRUCTION IN THE PATH OF SAID LATCHING PORTION, AND OPERATING MECHANISM FOR OPENING AND CLOSING THE CONTACTS INCLUDING A HANDLE AND INCLUDING MEANS FOR RESTORING SAID CONTACTS TO THEIR OPEN POSITION UPON RELEASE OF SAID ACTUATOR BY SAID OVERCURRENT LATCHING DEVICE, SAID CONTACT ARM AND SAID OPERATING MECHANISM HAVING MUTUALLY OBSTRUCTING MEANS IN THE RESTORING PATHS THEREOF IMMEDIATELY AFTER RELEASE OF SAID ACTUATOR, SAID OBSTRUCTING MEANS BEING EFFECTIVE TO ARREST THE HANDLE IN A PARTIALLY RESTORED TRIP-INDICATING POSITION.