US2913558A - Circuit breaker - Google Patents

Description

United lStates Patent GP CIRCUIT BREAKER Samuel A. Bottonari, Pittsburgh, Pa., assignor to Westinghouse Electric Corporation, East Pittsburgh, Pa., a corporation of Pennsylvania Application August 30, 1957, Serial No. 681,215

' 3 Claims. (Cl. 200-148) This invention relates to circuit breakers and more particularly to means for controlling rebound ofthe moving contact structure.

An object of the invention is to provide a circuit breaker embodying a movable contact structure movable at high speed with means for preventing rebound of the moving Contact structure.

Another object of the invention is to provide a circuit breaker embodying a high-speed movable contact structure with means preventing rebound of the contact structure when it is suddenly stopped in its opening movement.

The invention both as to structure and operation together with additional objects and advantages thereof, will be best understood from the following detailed description thereof, when read in conjunction with the accompanying drawing which comprises an elevational view, partly in section, of a circuit breaker embodying the principles of the invention.

Referring to the single figure ofthe drawing, the circuit breaker comprises generally a plurality of pole units (only one being shown) mounted on a base structure indicated generally at 11. The pole unit comprises a channel-shaped frame 13 of molded insulating material rigidly supported on the base structure 11 by means of a bracket 15 secured to the base structure 11 by means of bolts 17, the frame 13 being secured to the bracket by bolts 19 (only one being shown). The front of the frame 13 is secured by bolts 21 to a bracket 23 which is secured to the base structure 11 by bolts 25.

Supported in the rear wall 27 of the insulating frame 13 is an upper terminal stud 31 and a lower terminal stud 33. The studs 31 and 33 extend through suitable openings in the rear wall 27 of the frame 13 and have contact blocks or feet 35 and 37 respectively, suitably secured to their inner ends.

The upper block 35 supports the stationary contact latching positions.

structure indicated generally at 39 and a movable switch Y arm 41 comprising a pair of spaced arms (only one being shown) is pivotally supported by a pin 43 on `the lower contact foot 37. A movable contact structure indicated generally at 45 is mounted between the movable switch arms 41 for movement into and out of engagement with the stationary contact structure 39. The detail contact structure is fully disclosed in copending application Serial No. 530,062, filed August 23, 1955 by Robert C. Dickinson and Paul Olsson and assigned to the assignee of the present invention. For this reason only a brief description of the contact structure is given herein.

The stationary contact structure 39 comprises a mainl stationary contact 47 biased by a spring 49 for contact follow, and a stationary arcing contact 51. The movable contact structure 45 comprises a main movable contact 53 rigidly supported between the Contact arms 41 and a movable arcin; contact 55 biased by a spring 57 for contact follow.

The movable contact arm is connected by means of an operating rod 56 to an operating lever 58 forming part p 2,913,558 Patented Nov. 17, 1959 of the breaker operating mechanism mounted in the base structure 11. The rod 56 is pivotally connected by a pin 60 to the switch arms 41 and by a pin 62 to the operating lever 58 which is pivotally supported on a pin 64 in the base 11.

An operating linkage comprising toggle links 59, 61 and 63 is provided to releasably hold the operating lever 58 and consequently the movable contact structure in the closed position and to operate the movable contact structure to open and closed positions. The toggle link 59 is pivotally connected by means of a pivot pin 65 to the operating lever 58 and the toggle link 63 is pivoted on a fixed pivot 67 supported on a frame 66 mounted on the base structure 11. The toggle link 61 is pivotally connected to the links 59 and 63, respectively, by knee pivot pins 69 and 71.

The linkages 59, 61, 63 comprise two toggles, one of which 59-61 may be designated as the tripping toggle and the other 61-63 as the closing toggle. The tripping toggle 59-61 is normally slightly underset above a line drawn through the center of the pivot pins 65-71 and the closing toggle 61-63 is normally underset below a line drawn through the centers of pivot pins 67-69. The closing toggle 61-63 is normally prevented from collapsing downward by a Support member 73 pivoted on a pin 75 supported -in the frame 66 and having a shoulder portion engaging under the knee pivot pin 71. The tripping toggle 597-61 is normally prevented from collapsing -by means of a main latch member 77 pivoted on a pin 78 in the base 11 and connected by means of a link 79 to the knee pin 69 of the tripping toggle.

The main latch member 77 is held in latching position by an intermediate latch lever 81 pivoted on the pins 75 and biased (by means not shown) to latching positions. The intermediate latch lever carries at its upper end a latch roller 83 engaging a latch nose 84 on the -mainlatch 77 and at its lower end has a latching portion"85 normally engaging a latch roller 87 on a trip member 89 pivoted on a pin 91 in the frame 66. The trip member 89 is biased by spring means (not shown) to A bracket 97 secured to the trip member'89 has a screw 99 adjustably mounted thereon for cooperating with a trip device 100 shown -in the `form of a tripping electromagnet.

The circuit breaker is tripped open by operation of the tripping magnet 100 whose armature 101, upon energization of the magnet by a tripping impulse, engages the screw 99 and rotates the trip member counterclockwise causingthe latch roller 87 to release the intermediate latchv 81. The latching engagement of the main latch 77 with the latch roller 83 is of the slip-off type and as soon as the intermediate latch 81 is released it is moved to unlatching positions by the upward force applied to the/mainV latch through the link 79. The tripping toggle 594-61 immediately collapses upwardly permitting counterclockwise movement of the operating lever 58 and opening movement of the movable contact structure. During the collapse of the'tripping toggle 59-61 a portion of the toggle link 61 engages and actuates the support member 73 against the bias of a spring 110 to a non-supporting position, thereby freeing the closing toggle 61-63. The closing toggle thereupon collapses downward and during its collapse resets Iand relatches the tripping toggle 59-61.

The circuit breaker is closed by energization of a closing solenoid 111, the armature (not shown) of which is connected by means of a rod 113 to the knee pin 71 of the closing toggle. When the solenoid 111 is energized which may be effected either manually or automatically by closing a suitable switch (not shown), the rod 113 is thrust upwardly straightening the closing toggle 61-63,

and, since the tripping toggle 59-61 is now held in thrust transmitting position, the operating lever 58 is moved clockwise to close the breaker.

The opening movement of the movable contact structure is arrested by engagement of a surface 103 on the operating lever 58 with an abutment 105 on the trame 66. Due to the mass of the movable contactrstructure and the high-speed of its opening movement, the moving contact structure has a tendency to rebound after striking the abutment 105. Means are provided to prevent such contact rebound. This means forms a part of a gas-blast device puier indicated generally at 115 whichprovides a blast of air between the separating contacts. This putter device is described in more detail in Lingal and Frink Patent No. 2,734,971 issued February 14, 1956. The putter 115 comprises generally a chamber 117 deiined by a cup-shaped base casting 119 extending across the three poles of the breaker and integral with and supported by the bracket which supports the frame 13, and a diaphragm 121. The edge of the diaphragm 121 is clamped to a flange 123 on the casting 119 by clamp members 125 secured to the ange 123 by bolts 127. The center portion of the diaphragm 121 is clamped between two clamping members 129 and 131 which are secured on one end of a rod 133, the other end of which yis pivotally connected by a pivot pin 135 to the operating lever 58.

Threaded into an opening in the upper portion of the casting 119 is a pipe 137 which at its upper end is provided with a suitable nozzle 139 for delivering a blast of air to the contacts upon opening movement of the movable contact structure. The clamp members 129 and 131 are secured to the rod 133 on opposite sides of the diaphragm 121 by nuts 141 and 143 which are threaded on the rod. A compression spring 145 compressed between the casting 119 and a washer 147 on the rod 133 biases the rod and the operating lever 58 in Contact opening direction.

The means for preventing the rebound of the moving Contact structure when it is stopped during an opening operation comprises a U-shaped member 149 `rigidly clamped between the nut 143 and the clamp member 131 and movable with the rod 133. The resilient side portions 151 of the U-shaped member 149 are tapered slightly outwardly as shown and are adapted when the breaker approaches open position to engage friction material 153 securely bonded to the facing sides of the clamp members 125 with a wedging or squeezing action. As the breaker nears the open position the flared portions 151 engage the friction material and the friction generated thereby quickly and smoothly decelerates the opening movement of the parts thus preventing any rebound of the moving structure.

By changing the angle of the portions 151 or 153 or both, or by selecting a friction material having a greater or lesser coefiicient of friction more or less decelerating action can be obtained.

While the invention has been disclosed in accordance with the provisions ofthe patent statutes, it is to be understood that various changes and modications may be made in the structural details without departing from the spirit of the invention.

I claim as my invention:

1. A circuit breaker having stationary contact means and a movable contact structure having movable contact means thereon cooperating with'said stationary contacts to open and close said'bre'aaer and to draw an arc, operating mechanism operable to effect opening and closing movement of said movable contact structure, a gas-blast device having a Xed part and a part movable by said operating mechanism for assisting in the extinction of said arc, spaced friction means mounted on said tiXed part, and a member movable with said movable part of said gas-blast device having resilient portions disposed-to engage said spaced riction means during an opening op eration to decelerate' the opening movement of the movable parts of said circuit breaker.

2. A circuit breaker having stationary contact means and a movable contact structure having movable contact means thereon for cooperating with said stationary contact means to open and close said breaker andrto draw The invention provides an anti-rebound device that is emcient and requires few parts in addition to those used in devices without the anti-rebound device. No critical adjustment is required and such critical parts as pistons, cylinders, etc., are eliminated.

an arc, operating mechanism operable to move said movable contact structure to open and closed positions, a gas-blast device comprising a'diaphragm connected to be actuated by said operating mechanism to assist in the extinction of said arc, spaced friction means iixedly mounted on said gas-blast device, a member having resilient portions thereon movable with Isaid diaphragm and engaging said spaced friction means during an opening operation to decelerate the moving parts ofsaid circuit breaker.

3. A circuit breaker comprising stationary contact means and a movable contact structure having movable contact means thereon for cooperating with said stationary contact means to open and close said breaker and to draw an arc, operating mechanism including an operating lever operable to move said movable contact structure to open and closed positions, a gas-blast device comprising a xed chamber and a diaphragm for assisting in the extinction of said arc, a rod connecting said operating lever and said diaphragm for actuating said diaphragm, spaced friction means rigidly mounted on said xed chamber, and -a member mounted on saidrod and having resilient portions engageable with said spaced friction means during a closing operation to decelerate the moving parts of said breaker.

References Cited in the tile `oi this patent UNITED STATES PATENTS v McCarty ..Oct. 5, 1926

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