Patent ID: 8070203
Filing Date: 2011-12-06
Classification: B66C,Y10S

Abstract:
1. A method for operating vacuum-operated hoists comprising: providing at least one elastically deformable vacuum-operated lifting mechanism, configured to generate a displacement vacuum after placement on a load at the time of lifting of the load; providing a controllable vacuum generator; providing at least one motorized lifting drive; and providing a load detection device to detect weight of the load when picked up by the hoist, wherein the load detection device, at the time of each lifting process, after detecting that the load exceeds a predetermined tare weight of the hoist, generates a protection signal if i) the controllable vacuum generator is not turned on or ii) there is an insufficient vacuum, the protection signal performing at least one of: a) directly or indirectly deactivating the at least one motorized lifting drive by way of a switch-off control; and b) preventing further lifting of the load if, upon detection of the load and lift to be used, no pressure differential or an insufficient pressure differential is present, wherein the load detection device automatically switches on the controllable vacuum generator to protect the load or activates the controllable vacuum generator to generate a higher pressure differential, the method further comprising providing at least one of pressure sensors, valve position sensors, and probes on the vacuum-operated lifting mechanism to generate control signals to verify presence of a minimum vacuum, wherein the minimum vacuum is determined as a function of the load actually detected and serves as a threshold value for generation of the protection signal.