| 摘要 |
<p>A harrow has a driven shaft (1) and drum (2) fitting across the machine. The drum has radial blades (4) spaced along it and around its periphery. On dry ground an annular ring (24), in two halves to pass around the shaft, is bolted to the end blades. These rings have holes, on a pitch circle, in line with corresponding holes in the blades. Bars (41) pushed manually through these holes are retained by split pins (23). On wet ground, the bars are replaced by an overhead cage bolted to an arm (31) each end. This cage (3) has blades fitting between those on the drum.</p> |
