Abstract: A transport device, or hand truck (10), having a load carrying surface (26) that is mounted to move up and down along the hand truck (10). The level of the load carrying surface (26) is changed by the amount of air within a pneumatic cylinder (40). The amount of air in the pneumatic cylinder (40) is determined by a pneumatic adjustment subsystem (42) and the load on the load carrying surface (26). Preferably, the pneumatic adjustment subsystem (42) is set so that the top item located on the load carrying surface (26) is always at waist level. The pneumatic adjustment system (42) permits the pneumatic cylinder (40) to be offset an incremental amount respective to items of identical weight and height being removed from or placed upon the load carrying surface (26). Thus, as items are removed from the load carrying surface (26), the load carrying surface indexes upward so that the top item is readily available at waist level.

Abstract: A locking system for extension members on portable lifts or the like has a wedge block with a jaw face on one side and a sloped wedge face on the opposite side engaging a complementing fixed sloped face so that when the wedge block is moved upwardly the complementing faces cause the wedge block to also move horizontally into clamping position by way of the jaw face. The wedge block is moved upwardly responsive to turning of a screw threaded into the block.

Abstract: Apparatus for braking relative vertical movement between two vertical members includes a ramp mounted on one of the members to oppose a vertical face on the other. If the ramp member accelerates downwardly a wedging roller is wedged between the ramp and the vertical face. This roller is on a slide rod which normally compresses a spring carried at the bottom of the ramp, but downward acceleration on the ramp results in expansion of the spring and movement of the wedging roller into wedging position to stop the acceleration.

Abstract: A swing-up stabilizer for a portable lift has a bracing strut with a pivoted locking mechanism at its upper end including a locking plate on the strut which is spring biased into a tilted locking position biting the strut when the stabilizer is in an active ground engaging position or swung into a raised storage position located past an "at center" position whereat the strut is aligned with a pivotal connection between the strut and stabilizer.

Abstract: A multi-stage mast assembly has its mast stages stacked front to back when retracted and has front-to-back guide rollers and side-to-side guide rollers between the mast stages and a front carriage frame. An extrusion is used for the mast stages and the carriage frame. The extrusion has a central hollow rectangular column, inwardly facing channels at the front corners, outwardly directed flanges at the back corners, and pairs of central stub flanges at the front and back.

Abstract: A portable multi-stage lift is provided with multiple outriggers for stability. The lift cannot be raised unless the outriggers are positioned in a fully extended, load-bearing relationship with the lift.