Patent ID: 7090051

Claim:
A platform assembly comprising: at least one mast made of stacked detachably connected modular sections, said at least one mast being intended to be positioned onto the ground; 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 platform assembly comprises at least two of the following features (a) to (e): (a) a base coupled to said at least one mast. said base extending upwardly on top of a supporting plate connected to an implement jack embedded into said base, said base also having an external frame on which is connected at least one stabilizer arm, whereby height adjustment and lateral stability of the platform assembly are substantially improved; (b) each modular section of said at least one mast forms generally equally spaced apart steps to define a ladder and has upper and lower ends provided with reinforcing L-shaped transverse bars intended to be connected with upwardly extending bolts to the transverse bars of each adjacent section, whereby stronger and more reliable connection between adjacent sections is achieved; (c) the lifting mechanism includes: 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 said at least one 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 the 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; (d) said at least one sleeve of the platform is held in position and guided along said at least one mast by means of L-shaped pads made of ultra high molecular weight plastic material, said pads contacting and sliding along comers of said at least one mast when the platform moves up or down, whereby a smooth and reliable motion is achieved; and (e) the platform has a width and length that can be easily modified by connection thereto of additional modular, platform segments.