Patent ID: 7866445

Claim:
A lift machine comprising: a base having a longitudinal axis and a transverse axis, a support for supporting a load above said base, a lift actuator operatively connected between said base and said support for raising and lowering said support relative to said base, and a support stabilization mechanism operatively connected between said base and said support for stabilizing said support relative to said base during raising and lowering of said support by said lift actuator, said support stabilization mechanism comprising a pair of opposed linkages spaced apart along the longitudinal axis of said base, each of said pair of opposed linkages having a pair of lower torque tube link arms and a pair of upper torque tube link arms, said lower torque tube link arms having a lower torque tube rigidly connected therebetween and operatively pivoted to said base at a fixed location, said upper torque tube link arms having an upper torque tube rigidly connected therebetween and operatively pivoted to said support at a fixed location, said torque tubes extending in a direction generally parallel to the transverse axis of said base, said lower torque tube capable of transmitting torque from one of said pair of lower torque tube link arms to the other of said pair of lower torque tube link arms, said upper torque tube capable of transmitting torque from one of said pair of upper torque tube link arms to the other of said pair of upper torque tube link arms, said pair of opposed linkages being interconnected in such a manner that said pair moves in synchronization during raising and lowering of said support by said lift actuator and maintains said support substantially level even in the event that a center of mass of the load is offset from a vertical axis of said lift actuator.