| 摘要 |
PURPOSE:To permit a slewing base to be stopped at a target position without unnecessary time being taken by a method in which alteration and setting are made in such a way as to reduce the difference in angles between the brake starting position and the stopping position of the slewing base according to the lowering of revolving number of engine. CONSTITUTION:On the basis of information from a sensor 22 to detect the revolving number of an engine E, command voltage V from a controller 20 to a proportional valve controller 11 is altered in relation to a target slewing speed as the revolving number of the engine E is reduced so that the difference in angles between a brake starting position for the slewing base and a stopping position set by the setters 19A and 19B is reduced by means of a brake position setter provided to the controller 20. As the revolving speed of the engine E is orderly reduced from the maximum revolving speed, the brake starting position in relation to the stopping position is orderly altered, and braking is made along a changing curve of slewing speeds of fixed slopes. The slewing base can thus be stopped at a target stopping position.
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