| 摘要 |
990,482. Change-speed control. C. VAN DER LELY N.V. June 20, 1962 [July 18, 1961], No. 23841/62. Headings F2C and F2D. A tractor for drawing or pushing agricultural implements is so arranged that excessive draw-bar force causes an automatic adjustment of the transmission gear to reduce speed. The arrangement shown employs an hydrostatic transmission with swash - plate pump and motor units 12, 13, control being exercized on the pump swash - plate 19, but a mechanical transmission may be used. The pivot shaft 20 of plate 19 is connected to the output member 31 of an hydraulic servomotor unit 32, the input member 33 of which is operated by a manual control lever (not shown), carried by a shaft 10 and operating through a linkage 48, 45, 37. The upper end of member 37 is attached to a cross-arm 53, 54 whose ends are connected to spring- loaded longitudinal members 55, 56 which are attached to the power-lift linkage or other implement-sensing mechanism. Upon the draw-bar force exceeding a predetermined value one or other of the rods 55, 56 moves to displace cross-arm 53, 54 and member 37, thereby operating the servomotor input member 33 to tilt the pump swash-plate 19 to reduce pump output and thus the speed of the tractor. |
