GB432160A - Safety contact device for electrically controlled lifts, particularly for hatchway and cage gates - Google Patents

Abstract

432,160. Looking lift and well doors. INVENTIO AKT.-GES., Hergiswil, Nidwalden, Switzerland. Nov. 20, 1934, No. 33354. Convention date, Dec. 24, 1933. [Class 78 (iii)] Safety-mechanism for well-doors of lifts is arranged so that the contacts for establishing the main starting-circuit for the lift cannot be bridged improperly when the gate or door is open. When the switch-arm B, Fig. 5, on the gate post bridges the contacts T the lift can be started, but when it bridges the contacts L a light signal is shown and starting cannot take place even if the contacts T are bridged improperly. The closing of the gate causes the bolt P to be moved to its gate-locking position, this movement also swinging the bell-crank K sufficiently to break the contact L. A shortcircuit is thus removed in a circuit including a hand-controlled device, such as a pushbutton on the cage so that by pressing the latter, the bolt R can be made to move outwards and rock the lever W, thus forcing a sliding key r inwards and releasing a system of levers whereby the arm V is moved upwards to bridge the contacts T. When the desired floor is reached, the floor switch initiates the movement by which bolt R is moved rearwardly; its coned end contacting with a projection H on the rod V and effecting a positive breaking of the contacts T, with a consequential movement of the levers to their original position. The sliding key r and associated levers are shown in detail in Fig. 1. Three levers a, b, c are loosely pivoted on the shaft g. Lever c carries a lever d pivoted thereto at and having a pin-and-slot engagement with a fixed point e. The sliding of the key r tends to swing all three levers about the pivot g, but the mounting of the lever d is such that it must rock during this process about point e and it is prevented from rocking by a spur on the lower end engaging the peripheries of the levers a, b. Thus the initial movement of the key r causes wards on its outer end to move levers a, b only by regulated amounts until slots in the periphery register with the spur on the lever d. After this, all three levers are swung simultaneously so that the angular movement of lever d is transmitted to the rod V as previously described. When the contact T is broken by the coned end of bolt R, the lever d is moved to free the levers a, b which return to their initial position under the action of springs. Since the contacts T and L are in a closed casing, the only access to which is through the sliding bolt holes, it is impossible for them to be tampered with by unauthorized bridging.