Work vehicle

摘要

A tractor includes: (a) a one piece frame having opposite ends defined by respective members adapted for receiving ballast with the rear member including a hitch located below any mounted ballast, (b) a dual screen filtering arrangement located upstream of a radiator and an engine combustion air inlet, (c) an implement lift system including a main spring lift assist which is locked out when the implement is lowered and an auxiliary lift assist for increasing the lift assist for front-mounted implements but is mounted so as to join the main lifts assist to produce a near constant lift force during lifting the implement while producing a minimal lift force when the implement is completely lowered (d) short and long effective lengths of a steering pitman arm may be selected, for respectively minimizing steering effort or maximizing responsiveness, by respectively connecting a mounting point closest to or a mounting point farthest from a pivot axis of the arm to a drag link, (e) a steering wheel is tiltable together with a steering column about a u-joint of the latter to a selected position by operation of a cam-operated latch, (f) a hydrostatic transmission is accurately neutralized by speed and direction and brake controls including adjustable arms, rollers and cams, (g) a tractor hydrostatic transmission includes a manually-operable bypass valve which is shiftable to dump the pressure side of the pump for permitting the tractor to be pushed when the engine is not working, the valve being automatically moved to a normal position permitting normal operation of the pump in response to the pump being driven by the engine, and (h) a switch is mounted to a seat structure so as to open, in response to an operator leaving the tractor seat, the mounting of the switch to the seat being such that a load as small as 20 kg applied at any place on the seat will keep the switch closed.