Patent GB-776025-A (GB)
Title: Improvements in means for loading the actuating springs of circuit-breakers
IPC: H02K7/065
Filed: 1955-01-26
Abstract: 776,025. Tensioning springs. ETABLISSEMENTS MERLIN & GERIN. Jan. 26, 1955 [Jan. 28, 1954; Dec. 17, 1954], No. 2312/55. Class 10. A circuit-breaker actuating spring 28, Fig. 1, is tensioned and loaded by hydraulic means, a rocking lever 17, actuated by an electromagnet 13, causing a piston 37 to move downwardly in a cylinder 38, thereby forcing liquid therefrom past a non-return valve 43 into a cylinder 39 where it acts upon a piston 40 moving it downwardly to tension the spring 28. On each upward movement of the piston 37 the cylinder 38 refills spring and thus close the breaker, a push-rod 44 acting upon a valve 45 is operated. In the spring loading mechanism of Figs. 2, 3, two free-wheel devices 54, 57 are utilized. A shaft 51 turning in bearings 52, 53 is adapted to load, through a crank arm 67 and link 68, a spring 70. Fast on the shaft are free-wheel hubs 65, 66, the arm 58 of the race associated with the hub 65 being adapted to be rocked by a reciprocating core 59. The balls 64 in the hub 65 are so disposed that clockwise rotation given to the race causes the hub and hence the shaft to rotate whilst similar balls in the hub 66 allow the arm 52 of the race of hub 66 to free wheel during this period. In the spring unloaded position, the crank arm 67 takes up the position OY. Clockwise step-by-step rotation of the shaft 51 until, in crank arm position OX, the spring 70 is fully wound, is caused by reciprocation of core 59. To release the stored energy an additional impulse is given to the magnet to move the core 59 downwardly. The race of hub 65 then rotates clockwise moving the link 68 from dead-centre OX to allow the spring 70 to expand and rotate the shaft 51 in a clockwise direction through an angle α closing in consequence a circuit-breaker whose actuating mechanism is coupled to the shaft. Step-bystep spring -re-energization now commences the device 54, of which the race is rigidly fixed to the mechanism frame at 56 preventing the partially re-energized spring from turning the shaft and the crank 67 anti-clockwise whenever with liquid drawn by suction from a reservoir 41. The impulses emanating from magnet 13 cease when an arm (not shown) on the piston rod 42 acts upon a limit-switch. To liberate the the core 59 moves upwardly. The electromagnet control circuit comprises an arm 72 attached to and rotating with the shaft 51, a rail 73 encircling the shaft, contacts 76 and A, and a box 71 containing a tumbler switch arrangement 77 pivoted at 81 and make-and-break contacts 78, 79. The switch is actuated by an arm 80 moving with the core 59. The circuit contains a push-button starter 75. In the spring unloaded position the arm 72 is at Y and for 360-α degrees of rotation the spring is loaded, the arm 72 and rail 73 contact ensuring that impulses are given to the electromagnet via the make-and-break contacts and arm 80. The spring is fully loaded, Fig. 2, and the arm 72 has left rail 73 and is touching contact 76. Operation of starter 75 ensures the additional magnet impulse necessary to pull the core 59 down and release the spring 70. The arm 72 will then move to the rail 73 at Y cutting the starter 75 out of circuit and automatically restarting the step-by-step loading of the spring.