| 摘要 |
<p>A grass cutting unit has the height of cut determined by a ground roll (18). A reaction member (26) linked to the ground roll (18) has a captive screw-threaded shaft (28) carrying a hand wheel (32). A block (38) threaded onto the shaft (28) is linked to the frame (10) of the cutting unit so that rotation of the hand wheel (32) adjusts the height of cut. The weight of the frame (10) is arranged to act on the hand wheel (32) to urge together contoured surfaces of the hand wheel (32) and the reaction member (26) so as, during normal cutting, to prevent spurious rotation of the hand wheel (32).</p> |
