| 摘要 |
A pick box (3) and sleeve (6) combination comprises a sleeve-receiving aperture (5) in the box (3), with the sleeve (6) located in the aperture (5) and adapted, in use, to receive the shank (17) of a mineral cutter pick (7). A zone (33) of differential area is provided between the external periphery of the sleeve (6) and the aperture (5). A fluid sealing ring (29) is located to each side of the zone (33) of differential area, and a hydraulic fluid entry bore (30) is located intermediate the two sealing rings (29) and is in fluid flow communication with the zone (33), whereby upon admission of hydraulic fluid under sufficient pressure to the zone (33) via the entry bore, the fluid, being confined by the sealing rings (29), effects hydraulic, axial displacement of the sleeve (6) with respect to the box (3). The invention also includes a mineral cutting drum (1) provided with a plurality of such pick and box combinations, and also to a machine provided with at least one such drum.
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