| 摘要 |
<p>A timber-working head, and more particularly a timber-working head having a drive wheel arm is provided. The head has a frame, and a drive wheel arm pivotally coupled to the frame. The arm includes a rotary drive, a rotary union between the frame and the rotary drive. The rotary union includes a pivot sleeve to which the rotary drive is mounted. The pivot sleeve has an internal bore and an outer surface, with at least one first port between the bore and the outer surface. A shaft is positioned in the bore, with at least one fluid passage having a second port in fluid communication with the first port.</p> |
