Patent ID: 7810791
Filing Date: 2010-10-12
Classification: B66D

Abstract:
1. In combination with a hoist operated by a servo motor raising or lowering support elements supporting a load by a hoist control responsive to a load sensor detecting the total force acting on said support elements, said hoist controls including a float mode in which a load on the hoist is raised or lowered in response to a force manually applied to increase the sensed total force by a hoist operator; an acceleration sensing arrangement sensing accelerations of said load during hoist operation without being affected by the weight of said load; said sensing arrangement generating signals corresponding to said accelerations, a processor receiving said signals and determining therefrom the magnitude of dynamically generated forces acting on said support elements due to said load accelerations and compensating therefore when in said float mode by subtracting signals corresponding to forces imposed on said support elements solely due to accelerations of said load from signals from said load sensor corresponding to the total force acting on said load to correct for the forces acting on said support elements generated by said load accelerations and thereby determining when forces are manually applied to said load by said operator unobscured by said dynamically generated forces.