GB1498882A - Hydrostatic transmission - Google Patents

Abstract

1498882 Hydrostatic transmission control; linkwork DEERE & CO 7 April 1975 [26 April 1974] 14121/75 Headings F2W and F2K In a manual control linkage for a vehicle hydrostatic transmission system having separate transmissions driving tracks on opposite sides of the vehicle wherein forward or reverse movement of a lever 82 from a central neutral position acts through a linkage 132, 88, 84, 80, 76, 74 on a reversing and metering control valve 20 to effect forward or reverse drive of the vehicle at a speed proportional to lever movement, a rotatable plate 86 in the linkage is frictionally held between fixed plates 90, 92 in a manner which provides increased frictional resistance to movement of the plate 86 as the pivotangle of the lever 82 increases from the neutral position. The plate 86 carries pads 100, 102, 104, 106 of friction material which engage V-shaped abutment surfaces 108, 110, 112, 114 on the plates 90, 92. During rotation of the plate 86 the distance from the axis of rotation of the contact areas between the pads and abutment surfaces increases to provide increasing frictional resistance to movement of the plate 86 and thus provide the vehicle operator with "feel". An adjustably loaded spring 122 maintains frictional engagement between the abutment surfaces on the plates 90, 92 and the pads on the plate 86. A manually actuated latch 138 is engageable with a recess 142 in the plate 86 to hold the latter in its neutral position. A pair of pedals 46, 66 act through linkages 40, 60 (see Specification 1,498,883) on valves controlling the individual transmissions for steering purposes.