GB1170150A - Improvements relating to Vehicle Tandem Axle Suspensions. - Google Patents

Abstract

1,170,150. Tandem axle suspension. KIRKSTALL FORGE ENG. Ltd. 19 July, 1968 [26 July, 1967; 28 Feb., 1968], Nos. 34204/67 and 9709/68. Heading B7D. A tandem axle suspension comprises a pair of longitudinal support members 12, 13 which may be beams or leaf spring assemblies independently pivoted to the vehicle body about a transverse axis 15, and connected at their ends to a pair of axles 10, 11, the connections including surfaces making line contact whose lines of contact intersect at a point A midway between the longitudinal members on their transverse pivot axis. The bearing surfaces are provided at each end of the members 12, 13 by a flat plate 16 welded to the longitudinal member and a curved surface of a bearing pad 17 connected to the axle, horizontal forces being taken by a peg 18 with a curved head 181 engaging in an aperture 19 in plate 16. The bearing surfaces are held in contact by bolts 20. In a modification, Figs. 4, 5, 9 each connection between the leaf spring assemblies and the axles includes a substantially mushroom-shaped member 34, the upper and lower surfaces 37, 38 of the head 35 of which both consist of two plane surfaces inclined at a small angle to the horizontal meeting in diametral ridges 39, 40, the upper ridge engaging a plane surface 45 under the main leaf 46 of the spring. An annular member 36 closely surrounds the spherical side of the head 35 and is clamped by bolts 48, 49, (50) to the leaf spring, the annulus being permitted to move sideways with respect to the spring and tilt about an axis parallel to the spring by providing a clearance (151) between bolt 48 and the upper leaves of the spring, spacing the bolts 49 (50) from the sides of the spring, and introducing coil springs (52), (53), (54) under the heads of the bolts to allow for shortening of the horizontal separation between the members 34 at the end of the axle when one end of the axle is raised or lowered with respect to the other. Alternately the mounting of the pivot blocks 321, 331 may be arranged to allow transverse bodily movement of the springs. Horizontal forces are taken through contact between the annulus 36 and the surface 41 of the head 35, and on rebound, by contact between the ridge 40 and the rim 51 of the annular member. In another modification, Figs. 10, 11 (not shown), only the rear axle is connected to the springs as above, the forward ends of the spring being slidably mounted on the other axle (61) rotation of this axle being resisted by an A-shaped bracket (68) rigidly attached to the axle at its rear end, and pivotally mounted to a bracket (70) on the vehicle chassis 71 at its forward end, as described in Specification 1,108,206.