Abstract: A telescoping hydraulic hoist with tube stages formed from a heat treated aluminum alloy from one of the series 2000, 6000 or 7000 aluminum alloys. These alloys retain good “memory” properties, and under the force of a pressure spike undergoes a momentary elastic deformation which acts as a shock absorber, expanding the tube wall to absorb the peak stresses and resist buckling. The hoist of the invention is thus much lighter than a comparably rated steel hoist, and much more resistant to corrosion.

Abstract: A telescoping hydraulic hoist which improves stability and rigidity in the extended position without sacrificing the maximum extension length of the hoist and with fewer machined parts which may be dislodged or damaged in operation. The base member has a recess into which intermediate and inner tube stages recede when the hoist is in a fully collapsed position, and a stop-collar on the gland nut bearings overlaps the exposed end of the next broader tube stage, defining a limit of retraction for each intermediate tube stage, so that a tube stage when fully retracted contacts the exposed end of the next broader tube stage, thus dispensing with the need for stop rings.

Abstract: A telescoping hydraulic hoist formed from a non-corrosive material provides bearings and hydraulic seals about the bottom portion of each intermediate moving stage. The bearings and hydraulic seals are thus always maintained within the hoist and are not exposed to dust or particulate matter from outside the hoist. Air flows into and out of the air spaces between adjacent stages through air breathers. The hoist may also include variable length stroke limiters, and a cushion member which partially closes off the hydraulic inlet as the innermost stage is fully retracted to slow the hoist motion in the final stages of retraction.