| 摘要 |
The invention relates to a device at a rotator and grapple unit intended for tree handling and suspended at the end of a boom. The rotator (8) and grapple (11) are connected each to a pair of flexible operating lines (6,7 and, respectively, 9,10) from a hydraulic pump (1) via a control valve (3). For rendering possible completion of the unit with a hydraulic sawing device without adding two additional hydraulic hoses for this purpose, which would give rise to problems due to the combined bending and rotary movement at the crane tip and resulting heavily increased strains and wear on a bundle consisting of six hoses, according to the invention a branch line (13) is taken from the operating line (10) used for closing the grapple (11), which branch line is located in a place after the rotator (8). The branch line (13) extends to a hydraulic sawing device (15,16) via a pressure-sensing valve (14). This valve is opened when the operator after completed gripping function adjusts the hydraulic pump (1 ) to a higher pressure level in order thereby to drive the sawing device from the operating line (10). When the sawing is completed, the operator resets the pump to the original pressure level, and the return flow from the sawing device passes out through return lines (22,25) and the second operating line (9) of the grapple (11). The unit is thereby ready for a new setting, gripping and sawing operation. |
