GB386987A - Improvements in motor vehicles - Google Patents

Abstract

386,987. Endless - track vehicles. CARPMAEL, M. H., 24, Southampton Buildings, London.-(Martel, C. le Q. ; Staff College, Quetta, India.) July 27, 1931, No. 21453. [Class 79 (i).] Comprises a motor vehicle having front and rear road wheels and endless tracks for alternative use with the rear road wheels, in which the tracks are driven by means frictionally driven from the driving road wheels or a member coupled thereto, the arrangement being such that the friction drive only becomes effective as the weight of the vehicle is transferred wholly or partially from the driving wheels to the tracks. In the construction shown in Fig. 2, the track frames 1 are carried by links 2, 3 pivoted to the vehicle frame A and adapted to be actuated by jacks 8 so as to raise or lower the tracks from the ground. In the position shown the driving road wheels C are clear of the ground and pulleys 9 carried by the track frames and geared at 10, 11 to the track sprockets 6 are pressed against the wheels C so as to be frictionally driven thereby. Alternatively, the pulleys 9 may engage the wheels C while the latter are still in contact with the ground, the drive and the load then being distributed between the tracks and the road wheels. In the construction shown in Fig. 8, the tracks are carried by frames 1 detachably pivoted at 16 to the main frame A and having forks or stirrups at their rear ends 15 engaging the rear road wheel axle. In this construction the rear road wheel springs are partially compressed by the load on the tracks, and form an elastic connection between the tracks and the main frame. The tracks are driven by means of pulleys 9 which engage the road wheels and the external surfaces of the tracks. When the tracks are not in use the pivots 16 are disconnected and the track frames 1 are moved away from the rear wheel axle and jacked up on the main frame. Pulleys 9 may be provided with serrations engaging corresponding teeth on the tracks, these serrations on the pulleys being rough enough to give a good friction drive from the rear wheels without being sharp enough to damage them. The driving connection shown in Fig. 8 may be used with the construction shown in Fig. 2.