GB495377A - Improvements in and relating to brakes for hoists and the like - Google Patents

Abstract

495,377. Brakes for overhead travellers. AABACAS ENGINEERING CO., Ltd., and COOPER, W. J. F. May 6, 1937, No. 12987. [Class 78 (iv)] [Also in Group XXXIV] A brake for a hoist, overhead traveller, travelling crane or other like track apparatus comprises a shoe e pivoted at f<1> to a lever b rocking about a fulcrum b<1>. The outer end of the lever b is engaged by the extension stem a4 of an armature a<1> moving toward an electromagnet or in a solenoid a which has the lower portion of its bore filled with a fixed magnetic core a<2>. The shoe e has a curvature the axis of which is located beyond the pivot f<1> so that after application of the brake any further movement of the traveller, which carries the solenoid a, will result in increased pressure of the tilted shoe e against the track or like member g. Springs f<3> bearing against arms b<1> fixed on the lever b position the shoe normally in its medial position. A spring d cushions the downward pull of the core a', and when the latter contacts with the stationary core a<2>, a strong electromagnetic holding effect is produced. Springs &c. may be provided to facilitate release of the brake. A modification is shown in which two shoes are provided, each carried by an adjustable arm furnished with a screw forming a tilt-limiting stop. One or the other of these shoes increases its grip with motion of the traveller after application of the brake by reducing the air gap between the stationary and movable cores of the single solenoid which operates both shoes. The solenoid is energized either from the load hoisting controller or from the travelling controller. In further forms the track rail is gripped between two shoes, and the power means may operate to hold the brakes out of contact with the track against the action of springs. Specification 478,320 is referred to.