Patent ID: 7331425

Claim:
A lift machine comprising: a base, 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, each of said pair of opposed linkages having a lower torque tube link and an upper torque tube link, said lower torque tube link having a torque tube operatively pivoted to said base, said upper torque tube link having a torque tube operatively pivoted to said support, 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 the center of mass of the load is offset from a vertical axis of said lift actuator, wherein each of said lower and upper torque tube links has a pair of link arms, said link arms of said lower torque tube links being operatively pivoted to said link arms of said upper torque tube links, wherein each of said pair of opposed linkages further includes a lower link and an upper link, said upper link having a first end operatively pivoted to one of said pair of link arms of said upper torque tube link and a second end operatively pivoted to a first end of said lower link, said lower link having a second end cooperating with said base in such a manner as to permit translation of said second end of said lower link relative to said base during raising and lowering of said support by said lift actuator.