US1768885A - Circuit breaker - Google Patents

Description

y 1930- I c. D. BURROWS 1,768,885

C IRCUIT BREAKER Filed Feb. 19, 1927 3 Sheets-Sheet l WITNESSES: INVENTOR C/arence 0 BU/l'Oh/J.

July 1, 1930. c. D. BURROWS CIRCUIT BREAKER Filed Feb. 19. 1927 3 Sheets-Sheen 2 INVENTOR C/arence [1B urron/J.

' AfTORNEY Patented July 1, 193i UNITED STATES PATENT OFFICE CLARENCE D. BURBOWS, OF PEOBIA, ILLINOIS, ASSIGNOIB, TO WESTINGHOUSE ELEC 'I'RIC & MANUFACTURING COKPANY, A CORPORATION OF PENNSYLVANIA CIRCUIT BREAKER Application filed February 19, 1927. Serial No- 189,667.

M invention relates to circuit breakers and particularly to circuit breakers for controlling current supplied to small motors and domestic appliances.

One object of m invention is to provide a circuit breaker o the tumbler-swltch type wherein the switch is moved to open position in response to overload or short-circuit conditions.

Another object of my invention is to provide a circuit breaker of the tumbler-switch type wherein the switch blade is normally biased toward open position by a spring that is re-wound when the switch is moved to closed position, and wherein the switch is operated to open or closed positions with a snap action, by means of an over-center spring that is connected to the operating handle and to a clutch releasably connected to the switch, and wherein the clutch is actuated in response to predetermined current conditions.

Another object of my invention is to provide a circuit breaker of the tumbler-switch type having the above noted characteristics and wherein calibrating means are provided for varying the power required to operate the clutch, whereby the switch may caused to open in response to predetermined current conditions.

A further object of my invention is to provide a circuit breaker of the tumbler-switch type that is trip-free of the operating handle and wherein the circuit breaker will open in response to predetermined current conditions, regardless of the position of the operating handle.

These and other objects of my invention that will be made apparent throughout the further description thereof are attained by means of the circuit-breaker apparatus hereinafter described and illustrated in the accompanying drawings wherein Figure 1 is an exploded view, in perspective, of various parts of the circuit-breaker mechanism.

Fi 2 is a transverse section through the circuit-breaker housing, showing the circuit breaker in end elevation.

Fig. 3 is a transverse section of the hous ing, showin the opposite end of the circuit breaker in e evation.

Fig. 4 is a longitudinal section of the housing, showlng the circuit breaker in the side elevation.

5 is a view, partially in longitudinal section and partially in elevation, of the c'ircu1t breaker shown in Figures 2, 3, and 4.

Fig. 6 is a transverse section of the clutch mechanism taken on the line VI-VI of Fig. 5.

eferring to the drawin s, the ci.cuit breaker comprises a housing made of porcelain, molded composition or any suitable insulating material and adapted to contain the circuit-breaker apparatus. The circuitbreaker apparatus is mounted upon a sheetmetal supportlng frame 8 of U-shape that is secured to the bottom of the housing by means of screws 9.

Referrin particularly to Fig. 1, the switch-bla e member'll is mounted upon, and adjacent to the end of a hollow shaft 12 and oscillates between open and closed positions. When the switch is in closed position, it enga es contact members 13 and 14. The shaft an switch are normally biased toward the open position, indicated by dotted lines in Fig. 1, b means of a helical spring 15 that is woun about the shaft and has one end connected thereto and the otherend connected to a supporting frame 8. The spring is rewound when the switch is moved to the closed position shown in Figs. 1 and 2, wherein the switch member 11 is in engagement with the contact members 13 and 14.

An operating handle 16 is rotatably mounted upon the shaft 12 and is provided with an openlng 20 for receiving a yoke member 17 that constitutes a portion of a clutch mechanism to be hereinafter described. The clutch yoke 17 is ofU-shape and the end portions 18 and 19 thereof are rotatably mounted in bearings 10 in the supporting frame 8 and also serves as bearings for the shaft 12 which extends through the ends of the yoke. The end portion 18 is provided with a pair of oppositely disposed notches 21 for receiving clutch pins 22 that are feathered in longitudinal notches 23 in the end of the shaft 12.

.operating handle. yoke is limited by the stop members 35 and 736 formed integrally with the supporting The clutch pins 22 are carried by a collar 22A that is threaded upon an adjusting rod 24 which extends through the hollow shaft 12. A secondary clutch collar 25 cooperates with the collar 22--A and serves to lock the collar 22A in adjusted position upon the rod 24 and also serves to provide an annular groove 26 for receiving a shifting bar 27. The bar 27 is pivoted upon a'shaft 28 provided with an armature 29 which is actuated by an electromagnet 31 that is connected in series with the switch contacts 13 and 14, and is supported upon plates 40 attached to the frame 8. g

The operating handle 16 is provided with a pin 32 upon which a guide rod 33 is pivoted, the latter extending through an opening 30 in the yoke 17.

A compression spring 34 surrounds the rod 33 and is disposed between the pivoted end of the rod and the yoke 17 The urpose of the spring 34 is to move the clutc yoke 17, the shaft 12 and the switch 11 to open or closed positions with a snap action, in re-.

sponse to a predetermined movement of the The movement of the plate 8, and the movement of the shaft 12 and switch blade 11 is limited by the arm 37 fixed to the shaft 12 and operating between stop members 38 and 39 on a stop plate 41 secured to the frame 8.

As shown in Figs. 1 and 2, the switch member is in closed position and is rotated in a clockwise direction to open position, as indicated by the arrow in Fig. 1. To open the circuit breaker, the handle 16 is first turned counter-clockwise, thus moving the pin 32 beyond the line intersecting the plane of the longitudinal portion of the yoke 17 and the axis of the switch shaft 12, at which time the compression spring 34 causes the clutch yoke 17 to rotate clockwise and open the switch with a snap action. The opening 20 in the handle 16 is of sufiicient length to permit of the necessary relative movement between the handle and the clutch yoke.

To close the switch, the operating handle is turned in a clockwise direction and the instant the shaft 32 passes beyond the line previously referred to, the switch is moved to the closed position by means of the compression spring 34. During the closing movement of the switch, the spring 15, which is weaker than the spring 34, is re-wound, so that it normally tends to bias the switch towards open position.

Under severe overload or short-circuit conditions, the armature 29 is drawn toward the electromagnet core, thus moving the clutch collars 22a and 25 outwardly and with drawing the clutch pins 22 from engagement with the yoke end 18. The shaft 12 is then free to rotate with respect to the clutch yoke 17, and the spring 15 forces the switch to open position with a snap action. If the shortcircuit or overload conditions prevail until an attempt is made to re-close the circuit breaker, the clutch will be held out of o erative position, and it will'not be ossib e to move the switch member to closed position. If, however, a short-circuit or overload occurs while the operating handle is in the hands of the operator, the circuit breaker will open, regardless of the position of the operating handle. The circuit breaker is, therefore, trip-free of the handle.

The clutch collars 22a and 25 are yieldingly held in the closed operative position with respect to the clutch oke by means of a compression spring 42 wliich surrounds an adjusting rod 24 that is disposed in a recess 43 and engages an enlarged end 44 of the adjusting rod. The spring 42 normally tends to yieldingly retain the clutch pins 22 in operative engagement with the clutch yoke. The clutch collars 22a and 25 may be adjusted longitudinally of the rod 24 and thus vary the force required to cause release of the clutch. The mechanism may, therefore, be calibrated to cause the circuit breaker to open at any redetermined current condition.

A therma element, such as a bi-metal strip or disc heated by current conducted therethrough or b an associated heater connected in series wit the switch terminals, may be substituted for the electro-magnet.

A cover plate 45 is detachably mounted on the casing 7 and is provided with a slot 46 through which the operating handle 16 extends to render the switch manually operable from the exterior of the housing. The slot 46 is closed by an arcuate sealing plate 47 attached to the handle 16.

\Vhile I have illustrated but one embodi ment of my invention, it will be apparent to those skilled in the art, that various changes, modifications, substitutions, additions and omissions may be made in the apparatus illustrated without departing from the spirit and scope of my invention, as set forth in the appended claims.

I claim as my invention 1. A circuit breaker comprising a movable contact member, means normally biasing the contact member toward open position, an operating device including an overcenter spring and releasably connected to the said contact member for moving the contact member to open position and to closed position against the action of said biasing means and. current responsive means for disconnecting the operating device from the contact member for permitting the said biasing means to move the contact member to open position.

2. A circuit breaker comprising a movable contact member, means normally biasing the contact member toward open posit-ion, an operating means including an over-center spring llt releasably connected to the said contact mem ber for moving the contact member to open position and to closed position against the action of said biasing means and for yieldingly retaining the contact member in either open or closed position.

3. A circuit breaker comprising a movable contact member, means normally biasing the contact member toward open position, an operating means having co-operating, relatively movable elements one of which is releasably connected to the said contact member and the other of which is manually operable for moving the first said element when the second said element is moved a predetermined distance, means for yieldingly retaining the said elements in extreme positions of movement, and current responsive means for dis connecting the first said element from the contact member.

4. A circuit breaker comprising a contact member, a switch member movable into and out of engagement with the contact member, a spring normally biasing the switch member into open position out of engagement with the contact member, a clutch means releasably connected to the switch member, an operating member, a spring connecting the operating member with the clutch member for moving the switch member into or out of engagement with the contact member in response to a predetermined movement of the operating member, and current responsive means for releasing the clutch member to permit the switch to be moved to open position by the first said spring in response to predetermined current conditions.

5. A circuit breaker comprising an oseillating switch member, a clutch means releasably connected thereto, an operating member, an overcenter spring connecting the clutch means and the operating member for moving the switch member to open and closed positions with a snap action in response to a predetermined movement of the operating member, a spring normally biasing the switch member to open position and adapted to be re-wound when the switch is moved to closed position, and current responsive means for releasing the switch member from the clutch means for permitting the last said spring to move the switch member to open position in response to predetermined current conditions.

6. A circuit breaker comprising a switch member movable to open and closed positions, a shaft for the switch member, a support for the shaft, a spring attached at one end to the support and at the other end to the shaft for normally biasing the switch toward open position and adapted to be rewound when the switch is moved to closed position. a clutch member 1 tatably mounted on the shaft and rclcasably secured thereto, an operating member rotatably mounted on the shaft, a spring connecting the, operating member to the clutch member for moving the switch member to open and closed positions with a snap action in response to a predetermined movement of the operating member and to the current responsive means for releasing the clutch member to permit opening movement of the switch by the first said spring in response to predetermined current conditions.

7. A circuit breaker comprising a contact member a switch member movable into and out of engagement with the contact member, a spring movably biasing the switch member into open position and out of engagement with the contact member, a clutch means releasably connected to the switch member, an operating member, a spring connecting the operating member with the clutch member for moving the switch member into and out of engagement with the contact member in re sponse to a predetermined movement of the operating member. current responsive means for releasing the clutch means to permit the switch to be moved to open position by the first said spring in response to predetermined current conditions, and adjustable means for controlling operation of the clutch means.

8. A circuit breaker comprising a switch member movable to open and closed positions, a hollow shaft for the switch member, a support for the shaft, a spring for normally biasing the switch toward open position and adapted to be re-wound when the switch is moved to closed position. a clutch member rotatably mounted on the shaft and releasably secured thereto, an operating member rotatably mounted on the shaft. a spring connecting the operating member to the clutch member for moving the switch member to open and closed positions with a snap action in response to a predetermined movement of the operating member. a current responsive means for releasing the clutch member to permit opening movement of the switch by the first said spring in response to predetermined current conditions. an adjusting rod extending through the said shaft and connected to the clutch means. and a tcnsioning spring mounted on the rod for controlling the operation of the said clutch means.

In testimony whereof. T have hereunto subscribed my name this l l-th day of l eln-uary,

CLARENCE D. BURROWVS.

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