| 摘要 |
PURPOSE:To make the capacity of a fluid pressure source smaller to the utmost by constituting a valve operating mechanism so as to regulate the extent of supply pressure in the fluid pressure source so as to cause it to be applied to the requisite operating pressure conformed to a shift mode of the operating mechanism. CONSTITUTION:As for a valve operating mechanism 4, when it is shifted down to 1-3 gear speeds by a change lever 21 as well as when it is shifted up to second gear speed, a high pressure valve 16 is turned to ON, and a low pressure valve 18 to OFF, respectively. With this on-off operation, compressed air in a tank T is fed to each side of valves 7A-7C and 8A-8C at high pressure via the valve 16 and a check valve 17. On the other hand, when it is shifted down to four gear speed as well as when shifted up to 3-5 gear speeds, the high pressure valve 16 is turned to ON and the low pressure valve 18 to OFF, respectively. With this constitution, the compressed air in the tank T is fed to each side of these valves 7A-7C and 8A-8C at low pressure via the valve 18 and a check valve 19. Consequently, work of the compressed air lessens as compared with the case that the high pressure compressed air is uniformly fed to the whole speed range.
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