GB649851A - Improvements in or relating to agricultural implements - Google Patents

Abstract

649,851. Agricultural implements. INTERNATIONAL HARVESTER CO. OF GREAT BRITAIN, Ltd. Aug. 4, 1948, No. 20574. Convention date, Aug. 16, 1947. [Class 6(i)] A tractor drawn agricultural implement is provided with a hydraulic cylinder unit operable from the tractor by fluid pressure for effecting movement of an adjustable part of the implement, the cylinder unit being provided with adjustable stop means for limiting the stroke of the piston and means are provided accessible to the tractor operator for selectively adjusting the stop means. As shown, a disc harrow is provided with a hydraulic cylinder 41 connected by links 46, 47, 48 to transverse portions of cranked axles 34 for raising and lowering the discs 26. The cylinder 41 is provided with a valve 59 normally maintained open by a spring 63, the plunger 58 of the valve being connected by a cable 67 to a chain 68, the links of which are selectively locked in a yoke 70 by the tractor operator through a cable 73. The cable 67 is trained over a pulley 65 mounted on a bracket 64 connected to the plunger 45 of the piston 44. Oil is fed into either end of the cylinder 41 through hoses 54 and 50 under the control of valve mechanism on the tractor. When the chain is locked in position and oil is pumped through hose 50 the movement of the piston 44 causes the cable to tighten and close valve 59, the pressure building up behind the valve causing it to close before the cable is fully taut. The oil in the cylinder is locked in position and the tools are raised by pumping oil through hose 54 to open valve 59. The stroke of the piston is adjusted by altering the position of the chain in the yoke 70 which causes the valve 59 to close at a different position in the stroke of the piston.