| 摘要 |
<p>Provided is a boom telescoping control unit (40) for controlling a telescoping operation of a telescopic boom (10) having a plurality of movable boom members (12b to 12e). The boom telescoping control unit (40) comprises automatic telescoping control means (41) to perform an automatic telescoping control for sequentially moving the movable boom members (12b to 12e) according to a regular boom-telescoping sequence; individual telescoping control means (42) to perform an individual telescoping control for moving only a manually selected one of the movable boom members individually; control switching means (45) including a selector switch (32) for selecting between the automatic telescoping control and the individual telescoping control, wherein the control switching means switches, based on the selection by the selector switch, between the two telescoping controls; automatic-telescoping-control switching prohibition means (43) operative to make a prohibition against switching from the individual telescoping control to the automatic telescoping control, irrespective of the selection by the selector switch (32), under a condition that, when the telescopic control selected by the selector switch (32) is switched from the individual telescoping control to the automatic telescoping control, the movable boom members (12b to 12e) have been moved in a sequence different from the regular boom-telescoping sequence; and switching-prohibition release means (44) to release the prohibition when the entire telescopic boom (10) has been brought into a maximally retracted or extended state.</p> |
