| 摘要 |
The invention is a lifting device for use in lifting a load. The device is used for example between a crane hook and the lifting chains attached to the load. The device hooks onto the crane hook and the chain passes over a guide wheel which in one position, when the chain does not take the weight of the load, the wheel can turn freely enabling the device to be moved horizontally relative to the load to any desired location, and when the chain does take the load, the wheel is placed in a locked position so that it cannot turn and by this means the device can be positioned so as to ensure that when the load is lifted it will be in a predetermined position e.g. level. The wheel is carried by a spindle, the ends of which pass through slots in a pair of side plates of the device and when the device is loaded, the spindles rest on the bottoms of the slots ensuring that the plates take the load. The guide wheel has teeth of which adjacent teeth engage on opposite sides of a pin which prevents the wheel from turning but the pin is located so as not to be directly loaded by the load. When the device is unloaded, the teeth are moved clear of the pin and the wheel can rotate. |
