Patent GB-577329-A (GB)
Title: Improvements in or relating to spring-operated driving mechanism for electric switchgear
IPC: H01H75/04
Filed: 1944-02-01
Abstract: 577,329. Automatic circuit-breakers ; actuation of switches. REYROLLE & CO., Ltd., A., ALLAN, A., and SMALL, J. Feb. 1, 1944, No. 1847. [Class 38 (v)] Spring-operated driving mechanism for electric switch gear, in which the movement of a single driven member performs a number of successive alternate opening and closing operations, comprises two or more springs from which the energy is released in succession and means for preventing the release of energy from one spring while another is in operation and for limiting the movement of the driven member after each operation, external means for subsequently releasing it for the next operation being provided. In one form the driven shaft B, Fig. 1, carries a gear B<1> in mesh with gears mounted through pawls A<3> and ratchets A<4> on shafts A<1>, of which two only are shown and which are connected to torsion springs A fixed at one end. The springs are wound by partial rotation of the shafts A<1> by the engagement of arms D thereon with a cam E on a motor or hand-driven sleeve E<1>, the shafts being retained by the engagement of projections G thereon with triggers G<1>. The springs are released by means of afreely mounted trip plate H having studs H<2> thereon engaged by an externally-operated trip lever M. The shaft B carries a toothed stop plate J engaged by an arm K. The stop arm is released at the beginning of an operation by a cam L which engages an arm K<1> integral with the arm K and is carried by a sleeve L<1> with the plate H<2>, the stop plate J being connected to the release plate L by a pin-and-slit connection J<1>, L<2> whereby the initial movement of the trip plate releases the stop arm K. In other forms, the springs are charged by rotating one end, the other end being connected to the parts to be driven. As shown in Figs. 4 and 5, the springs A carry pinions Q at one end meshing with a central pinion Q<1> operated for winding by a worm Q<2>. At the other end the springs carry double-ended arms R fitted with rollers R<1> to engage cam rings S<1> each having a radial slot S<2>, the rollers pertaining to each pair of opposite springs engaging one of the rings S<1>. With the springs wound up, one of the rollers R<1> enters a slot and exerts a torque, the rollers of the other three springs bearing on the inner surface of the rings and their unwinding being thus prevented. The roller emerges after a half revolution of the spring and the drive is taken up by a roller on the next spring entering the slot. The springs are rewound after all have made a half rotation. The inner surface of the rings may be cylindrical or may curve inwards towards the slots. The rotary member S is fitted with teeth S<3> engaged a pawl S' withdrawn by a solenoid. In a further modification, the cam consists of a disc with a radial, peripheral slot T, Fig. 8, and each spring carries a four-armed cross U fitted with rollers which engage therein in succession. The springs are rewound as they are discharged, each spring having a slotted disc V, Fig. 10, thereon engaged by an arm W<1> on a central winding shaft. In another form the springs are wound in pairs.