| 摘要 |
<p>A boom structure (12) for a tree processing apparatus (10) comprising a first upper channel member (18) oriented with its legs extending downward, a second lower channel member (20) oriented with its legs extending upward, and third and fourth channel members (22, 24) which are received between the legs of the upper and lower channel members with their legs facing inward. The four channel members are welded together to form a unitary structure of cruciform section. The side channel members define outer track means (23) which receive rollers (21) supporting a processing head (14), and inner track means (61) which receive support rollers (58) operatively attached to an actuating cylinder (38) for the processing head.</p> |
