Patent ID: 6883643

Claim:
A platform assembly comprising: at least one mast made of detachably connected modular sections, said at least one mast being intended to be positioned onto the ground, each of said modular sections being devised to form equally spaced apart steps and be used as a ladder; a horizontal platform mounted onto said at least one mast in such a manner as to be easily movable up and down along said at least one mast, said platform including a frame formed with at least one sleeve through which said at least one mast extends, said platform also including a floor; and a lifting mechanism to move the platform up and down along said at least one mast, said lifting mechanism being mounted onto the platform and operable from said platform; wherein said lifting mechanism comprises: a main hydraulic cylinder having an upper end pivotably connected to the sleeve of the platform and a lower end from which projects a piston having a free end with at least one hook pivotably mounted thereto for engagement with the steps equally spaced apart along said at least one mast, at least one hook-shaped bar having an upper end pivotably connected to the platform and a lower end shaped and devised to engage and hook onto the steps of the corresponding mast; and at least two back cylinders to apply a lateral pressure onto the main cylinder and to actuate said at least one hook-shaped bar so as to force said at least one hook-shaped bar to engage the steps or to retract from said steps in alternance; whereby the platform is lifted up when the piston of the main cylinder is pushed down, thereby improving the efficiency and speed of the lifting mechanism.