| 摘要 |
Method and unit intended for controlled restriction of cranes' working movements over the crane's working area, which operate with the aid of a schematic plan 21, which is made of the crane's working area, the restricted area or areas 23 and 24, into which the load-bearing member of the crane must not be moved, being marked on the plan. The plan is sensed in accordance with the movements of the load-bearing member, which on the one hand may be slewing movements stemming from the rotation of the crane mast or a jib, and on the other the drive movements of a crab, and which from signals originating from the sensing are transmitted to the corresponding movement drive elements. The schematic plan 21 is fitted to a load- bearing member 12, which is capable of rotating as a function of the turning movements, and the sensor element 15 is moveable linearly as a function of the said drive movement. Run-on movements are allowed for in that the sensing elements are adjustable, and/or that the restricted areas 23, 24 on the schematic plan are made correspondingly larger. For cranes with more than one working area, some sensing elements can cause a switch to another speed, whilst others can produce a stop. The markings for lowering and linear drive respectively may each be assigned to their own sensing unit. <IMAGE>
|
