| 摘要 |
PROBLEM TO BE SOLVED: To provide a crane turn decelerating control device which enhances operational efficiency by enabling a crane operation to be carried out to a maximum up to near the boundary of a limit operational area even while the turn of a crane is being braked. SOLUTION: This device includes: an operating radius calculating part 36 for computing an operating radius (Rn) at predetermined time intervals; an operating radius varying rate calculating part 37 for computing the varying rate(VR) of the operating radius from the operating radius (Rn); a desired deceleration angular velocity calculating part 34 for computing the braking time (t1) and the angular velocity required to achieve braking in a turn braking area (G); an anticipated operating radius calculating part 38 for calculating an anticipated operating radius (Re) after the braking time (t1); and a turn controlled variable calculating part 35 which calculates a stopping position corresponding to the anticipated operating radius (Re) on the boundary of a stopping area (AC) to control continuously the drive of a boom in its derricking direction and/or in the direction of its expansion and contraction when the boom has reached deceleration-starting turning anglesθd1,θd2 which are ahead of the stopping position by a predetermined braking angle, and which, from the turning angular velocity according to the controlled variable of a turning control lever 51, computes a command to stop a turning element by decelerating the turning element gradually at the angular velocity employed in the turn braking area (G).
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