| 摘要 |
1,273,757. Mowers. JACOBSEN MFG. CO. 29 Sept., 1969 [18 Oct., 1968], No. 47769/ 69. Heading A1F. A tractor supports gauged, castor mounted mowers 57, 58, 59 directly in front of each of the ground wheels 11, 12, 13. The engine and other parts of the tractor are distributed such that the weight of the tractor and mowers is evenly placed on each of the ground wheels and the seat 43 is placed in a position over the centre of gravity of the machine. Steering of the tractor is effected by articulation of the rear wheel 13. Motive power is supplied by a rearwardly mounted engine 46 through a fluid transmission conducted from the pump (168) Figs. 4, 10 (not shown) through the hollow framework of the tractor and by flexible tubes 177, 179 to the rear mower motor; by tubes 172, 173, 174, 175 to the two front mower motors; by pipe lines 164, 166 to the two front wheel traction motors and by tubes 102 to the cylinder 97 powering the mower lift ram 101. The two front mower motors are fed by the transmission in parallel to give a differential effect. When out of the neutral position the mower motors are also in parallel drive which drive is in series with the traction drive to the wheels so that the tractor speed is in a fixed ratio with the mower rotation. Further the drive to the mower lifting ram 97 is similarly in proportion to the tractor speed. Lifting of the mowers is accomplished on extension of the ram which through the links 103, 121. pivots cam plates 113, 127 upwards in a vertical plane to engage rollers 114, 128 respectively pivoting the lift arms 74 about pins 76 on the tractor frame. This lifts the front mowers mounted on the other end of the lift arms 74. The rear mower is lifted by means of a linkwork 121 also powered by the ram 97 which includes an adjustable lost motion coupling before it operates the cam plate 138. In this way the mowing may be started and finished along a line at right angles to the mowing direction. The cam plates are profiled with projections 119, 154 so that when in the raised operative position the ram need not be powered to hold the mowers off the ground. To lower the mowers the drive to the ram must be reversed to disengage the cam plates at which time the lowering of the mowers is cushioned by springs 155.
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