Patent ID: 7413056

Claim:
Lifting device, comprising: a lower structure, an upper structure movable with respect to the lower structure between a lowered position and a raised position, a linkage connecting the upper structure to the lower structure, and including at least one articulated arm, an actuator operatively interposed between the lower structure and the linkage, to drive the movement of the upper structure between its lowered position and its raised position, a connecting element between the actuator and the linkage, said connecting element being in form of an auxiliary arm having a first end articulated to said arm of the linkage for rotation with respect to a first articulation axis and a second end rotatably supporting a cam-following roller for rotation with respect to a second axis, said roller cooperating with a fixed cam, wherein the actuator is pivotally connected to said second end of the auxiliary arm for rotation with respect to said second axis, so that said second axis always remains located below said first articulation axis, wherein the actuator is a hoist device using a belt, cord or chain and including a number of pulleys on which said belt, cord, or chain is engaged, the hoist device including a plurality of hoist devices arranged side by side and operating in synchronism, whereby, when the actuator is activated to cause a lifting movement of the device, said auxiliary arm acts as a pushing strut subjected substantially only to compression stresses directed in the longitudinal direction of the auxiliary arm.