| 摘要 |
822,604. Mowing machines. BROWN TRACTORS (ENGINEERING) Ltd., D. July 30, 1956 [July 29, 1955], No. 21944/55. Class 6(3). To permit break-back of the cutter-bar f when it strikes an obstacle, a mower hitched to a tractor by three links and connected to the lower links c by hitch pins e, is connected to the pin on the cutter-bar side through a plate n pivoted below the mower frame a on a vertical pin s attached to the frame so that the frame can pivot about the other hitch pin to the position shown in ghost lines when a stop w on the frame contacts a plate member v. To prevent break-back until an obstacle is struck, a ball or roller m mounted on the plate n is held in a depression to hold the plate n in the position shown. The depression is formed in the edge of a cam p on a plate q, pivoted at r on the mower frame a beneath the plate n and loaded adjustably by a compression spring t to detain the roller m until the cutter-bar f strikes an obstacle. Reversal of the tractor causes the roller m to run along the cam p and re-engage the depression. By varying the length of the upper link of the hitch, the pitch of the cutter-bar f is varied. A tie-link y between the lower links c may be lengthened or shortened by screw means to vary the angular position of the mower with respect to the tractor and thus adjust the lead of the cutter-bar. The Provisional Specification describes also a ball or roller held normally by two detents, each in a cam surface on one or the other of two plates pivoted on the mower frame. |
