GB814054A - Lift truck - Google Patents

Abstract

814,054. Motor propelled trucks; hydraulic driving gear. VEREINIGTE WESTDEUTSCHE WAGGONFABRIKEN, A. G. May 31, 1957 [June 8, 1956, No. 17414/57. Classes 79(2) and 79(3) In a fork lift truck, a hydrostatic transmission system 11, Fig. 1, is enclosed in a box-like housing 7 mounted on driving wheels 8 and having the guide mast 4 for load carrier 5 attached to the front end and a driving motor unit 1 on steerable wheels 10 attached to its rear end. The driving wheels 8 are mounted on shafts 20, Fig. 3, in casing 15a attached to the sides 14a of the transmission housing 7 and carrying hydrostatic motors 17a, 17b which drive the wheels through pinions 18, 19 (not shown). Apertures 39 are provided in the side walls 14a to permit assembly &c. from the outside and are offset so that the motors can be arranged one above the other. Projections 37a on the shafts 20 engaging apertures in the walls 14a, 14b locate the casing 15a for assembly. The hydrostatic pump 11 is mounted on a bracket 12 attached to the driving unit 1 and is arranged to project into the transmission housing 7 on assembly, the drive being obtained from an internal combustion engine 3À or an electric motor and batteries. The pump 11 is pivoted in a vertical axis 21 Fig. 4 and is adjusted about the pivot for varying the transmission ratio by a servo cylinder 24, coupled to the pump 11 by a pin 25. The cylinder 24 slides over a fixed piston 23 and piston rod 22 attached to the side walls 14a, 14b and supplied with pressure fluid through pipes 26, 27 from a servo valve 28 (not shown) operated from a control lever, and connected to the pump body to provide follow-up control. The supply for the servo-system may be taken from the scavenging oil pump of the hydrostatic transmission, a throttle valve 38 (not shown) being inserted to prevent a large drop in pressure in the scavenging system.