| 摘要 |
923,819. Automatic circuit-breakers; switches held set and freed mechanically. BRILES PRODUCTS Inc. March 13, 1961, No.9071/61. Class 38 (5). An automatic circuit-breaker has a pair of fixed contacts 18. a pair of movable contacts 26 pivotally-mounted on an insulating bar 30 and a helical bi-metallic element 44 connected between the movable contacts and secured at one end to the bar 30. The other end of the element 44 forms a finger 52 which abuts a shoulder 76 of a slidable release member 54 to hold the contacts closed against the bias of a spring 42. A rod 82 is secured to an operating plunger 84 and extends through the release member 54. A latch 98 is housed in a slot 96 in the rod 82 and is pivoted on a pin 100 which is secured to the release member 54 and extends through a slot 102 in the rod 82. The rod 82 is provided with a cam pin 104 which extends through an inclined slot 106 in the latch 98. When the circuit-breaker is closed, Fig. 4, the upward thrust of the spring 42 maintains the latch 98 in abutting engagement with a flange 62. To open the switch manually the plunger 84 is pulled up and the upward movement of the rod 82 causes the pin 104 to cam the latch 98 out of engagement with the flange 62. This permits the parts of the circuitbreaker to move up into the positions shown in Fig. 6. Under overload conditions, the heating of the bi-metallic element 44 causes the finger 52 to be removed from abutting engagement with the shoulder 76 to release the moving contact assembly and at the same time to remove the thrust of the spring 42 from the latch 98 so that a spring 90 acting on the plunger 84 moves the plunger to free the latch 98, the circuit-breaker parts then moving to the positions shown in Fig. 6. The circuit-breaker is closed by depressing the plunger 84 until the contacts close and the latch is engaged. The sensitivity of the circuit-breaker is determined by the resistance of a ring 40 which provides a shunt path between the contacts in parallel with the element 44. The current in the helical element 44 may provide a magnetic blow-out and cause eddy currents in the rod 82 to provide an opening accelerating force. A cylindrical barrier 22 and a transverse barrier 24 suitably direct the arc gases. The spring 42 acts on the contact carrying members 28 on the opposite side of the pivots 32 from the contacts 26 so that a wiping action is obtained. The release member 54 is guided by a pin 79 which is fixed in the arrangement shown, though in modified constructions, Figs. 9-13 (not shown), the pin may be moved by an ambient temperature compensating element. These Figures also show other modified details. |
