Agricultural tractors controlled by hydraulic systems

摘要

1,043,760. Variable-speed gear and control. T. YAMAOKA. Oct. 27, 1964 [June 5, 1964], No. 43778/64. Heading F2D. [Also in Division B7] A cultivator or other agricultural tractor has two hydraulic systems, controlled by a single lever 50, respectively controlling a variable-ratio belt drive and reversing gearing arranged in series between engine 1 and driving wheels 6, 61. Movement of lever 50 in the direction G (Fig. 3), about axis I-I actuates Bowden cable 35 and lever 36 to move valve spool 34 in direction 38 permitting pressure fluid from hydraulic pump 24 to pass through valve inlet 33, chamber 47 and conduit 40 to pulley chamber 42, thereby increasing the effective diameter of pulley 9 to increase the vehicle speed. When the right-hand pulley flange has moved the required axial distance the valve body, which is movable by arm 45 engaging pulley groove 44, closes inlet 33. When lever 50 is moved in direction F valve spool 34 connects chamber 42 with reservoir 49. Pressure fluid from pump 24 is also delivered through conduit 26 to chamber 30 of pulley 12 to maintain the belt tension. On movement of lever 50 in direction I about axis II-II extension 51 of the lever moves spool 53 of valve 52 to connect pump 24 through valve inlet 55 with cylinder 60 thereby sliding gear 13, which is connected to piston 61, on splines on shaft 27 into mesh with gear 14 to drive the wheels 6, 61 through chain 18 in the reverse direction. On movement of lever 50 in direction H valve spool 53 moves to connect cylinder 60 with reservoir 49 permitting spring 62 to slide gear 13 into engagement with gear 15 and hence drive the vehicle in the forward direction through gear pair 16, 14.