| 摘要 |
PURPOSE:To enable perfect stoppage of machine body upon releasing of foot from a speed change pedal, by providing a lock mechanism interlocked to operate a hydraulic pump shaft through back/forth rotation of a speed change pedal and block the rotation at a neutral position. CONSTITUTION:When a speed change pedal is placed 3 at a neutral position, a neutral recess in a neutral lock cam 10 matches with a spool 21 and a shortcircuit path section thereof shortcircuits a delivery port 23a and a return port 24a of a hydraulic pump so as to reduce the pressure to zero thus stopping the rotation of a hydraulic motor completely. When an operator releases his foot from the speed change pedal 3, a neutral energizing arm 4 pushes an engaging pin 7 of a stop pin arm 6 and moves the pin 7 to the neutral position so as to bring the speed change pedal 3 and a HST speed change device H automatically to the neutral position thus shortcircuiting by means of a neutral lock valve A. Consequently, the speed change device H is brought into perfectly stopped state and safe state can be achieved.
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