Patent ID: 11970102
Assignee: HIAB USA INC.
Field: Mechanical elements (Mechanical engineering)
Classification: CPC B  F | IPC B  F

Claim 17:
18. A method of unloading a product from a vehicle using a liftgate, the method comprising:
storing energy in a hydraulic accumulator while the liftgate is being lowered under load, with the product on the liftgate;
after the being lowered, removing the product from the liftgate; and
after the removing, using the energy from the hydraulic accumulator to raise the liftgate;
wherein the liftgate is part of a liftgate assembly that includes:
a hydraulic power unit usable to raise the liftgate from the lowered position;
wherein the hydraulic power unit includes the hydraulic accumulator;
wherein the hydraulic power unit includes a pump that pumps hydraulic fluid from a reservoir;
wherein a selector for lowering with energy recovery engages the hydraulic power unit;
wherein the selector engages the hydraulic power unit only when a load on the liftgate exceeds a threshold load; and
wherein the selector includes a pressure sensor on the liftgate.