GB721170A - Improvements relating to endless tracks for tractors and other vehicles - Google Patents

Abstract

721,170. Endless tracks for vehicles. CUTHBERTSON, J. A. April 16, 1952, No. 9505/52. Divided out of 721,141. Class 79(1). A flexible unit for a vehicle endless track comprises longitudinally spaced abutment means which are interconnected by a flexible tension member, one of the abutment means extending transverse across the entire width of the unit and the tension member being looped slidably around the transverse abutment means in a transverse direction to form looping lying parallel to the ground so that transversely spaced longitudinal stretches are formed between the abutment means and a transverse stretch is formed across the entire width of the unit and increase in tension in one longitudinal stretch is transmitted through the transverse stretch directly across the entire width of the unit to another longitudinal stretch, and the tension member being in a unitary manner enclosed in, and the abutment means being in a unitary manner embedded in, rubber to form the unit, and the transverse abutment means being so constructed as to facilitate the transmission of the increase in tension. The endless track is formed by abutting a series of the flexible units, adjacent units being interconnected by inner and outer plates and bolts passing therethrough, the outer plates carrying ground engaging spades and the inner plates each carrying a pair of sprocket engaging teeth as shown in Fig. 1 of Specification 721,141. The units may be arranged to leave say 1¢ inches longitudinally between adjacent plates. As shown in Figs. 5 and 6, each unit 1 comprises longitudinally spaced series of pulley wheels 10, one series being staggered relatively to the other. Passing sinuously around the pulleys 10 and forming the longitudinal stretches 9a is a multistrand wire cable 9 forming the flexible tension member, which may be replaced by nylon or other textile cable, the ends of the cable 9 being joined together at 9c to form the transverse stretch 9b. The cable 9 is in a unitary manner enclosed in, and the pulleys 10 in a similar manner embedded in, a rubber block 14, holes 13 being provided for the bolts. A transverse flexible supporting strip 12 of canvas or other semi-stiff material engages the inner sides of the stretches 9a to prevent sharp bending of the stretches. The strip 12 may be replaced by rubber when the track is to operate under light load. In another arrangement, canvas strips engage both the inner and outer sides of the stretches 9a. In a modification, Fig. 10, each unit 1 is formed with two longitudinally spaced pairs of pulley wheels 15, 16, which are engaged by the cable 9 with its ends joined at 9c, thus forming the stretches 9a and 9b.