GB241253A - Improvements in linkages for force transmission - Google Patents

Abstract

241,253. Lloyd, G. E. June 16, 1924. Link-work; Bowden mechanism. - For the transmission of force at one or more intermediate points in the length of a linkage, as in the simultaneous application of brakes on a number of coupled vehicles, a bell crank at each intermediate point has its fulcrum constrained only in the direction of the intermediate applied force, being free to move in the direction of the continued transmission of force through the linkage. As shown in Fig. 1, the force is transmitted through links A, T coupled by a double bell crank B capable of translational movement in the general direction of the linkage and of turning movement to exert intermediate lateral forces upon the parallel links Dr, Dl which, with a link L are coupled by T-shaped bars Sl, Su mounted on fixed pivots Pl, Pu. In Fig. 2 an arrangement is shown for simultaneously applying brakes on a number of coupled vehicles V1, V2, V3, means being provided whereby the brakes are applied with greater force on the rear vehicle for the time being. The bell cranks B1, B2, B3, through which the brakes are actuated, are coupled to the actuating means through Bowden cables or equivalent means C1, C2, C3 and are connected to the brake arms G by parallel links H so that they are capable both of translational and turning movement, only the latter being effective in applying the brakes. To the fixed pivot P of each parallelogram is pivoted a strut J which, under the influence of a spring K, is adapted to make the parallelogram rigid. The transmitting cable, such as C2, C3, being connected to the end of this strut, it is however normally drawn back against the floating fulcrum M of the bell crank thus allowing collapse of the parallelogram whilst clearance is being taken up, after which the bell crank turns about the fulcrum M to apply the brake. In the case of the rear vehicle V3, the strut J being free, is drawn into engagement with the parallelogram to render this rigid and in one with the bell crank B whereby a greater leverage is obtained in applying the rear brakes. A modification is described wherein the linkage is employed to free brakes applied by springs. In this case the bell crank on the rear vehicle acts with reduced leverage.