Patent ID: 7152709
Filing Date: 2006-12-26
Classification: B62D,B66F

Abstract:
1. An industrial vehicle, comprising: a lower frame on front and rear lower sides of which front and rear wheels are installed respectively, the front and rear wheels being composed of left and right wheels; an upper frame having a cab with a steering wheel located on an upper portion thereof and coupled upside the lower frame; steering cylinders, each provided with left and right input ports and a driving chain connected at opposite ends to opposite ends of a corresponding one of the steering cylinders for moving the driving chain left and right by means of a pressure oil supplied to the left and right input ports; left and right sprockets driven by the driving chain; front and rear wheel steering cases having left and right pivoting shafts, the left and right pivoting shafts being coupled to the left and right sprockets on upper portions thereof and to the left and right wheels on lower portions thereof to transmit driving force to the left and right wheels; a rotary valve connected to a steering pump and a hydraulic tank, provided with left and right output ports and discharging pressure oil from the steering pump to the left and right input ports based on rotation of the steering wheel; and a plurality of fluid channels connected between the left and right output ports of the rotary valve and the left and right input ports of the front and rear wheel steering cases or between the left and right input ports of the front and rear wheel steering cases, wherein the plurality of fluid channels include: when the steering cylinders are provided on inner sides in relation to the left and right pivoting shafts in the steering cases and when the front and rear wheel steering cases are symmetrically provided, a first fluid channel having a right fluid channel connecting the right input port of the front steering case and the left input port of the rear wheel steering case and a left fluid channel connecting a left input port of a hydraulic cylinder of the front wheel steering case and the right input port of the rear wheel steering case; a second fluid channel connecting the right output port of the rotary valve and the right fluid channel; and a third fluid channel connecting the left output port of the rotary valve and the left fluid channel.