A cylinder propping system includes a sleeve and a locking member. The sleeve includes an outer wall that defines an inner cavity and a ledge. The inner cavity is sized to receive at least a portion of a cylinder assembly therein. A first end of the outer wall is configured to hingedly couple to one end of the cylinder assembly. The ledge is spaced apart from the first end. The locking member is sized to engage with the ledge, between the ledge and a cylinder housing of the cylinder assembly, to prevent movement of the cylinder housing in at least one direction along a central axis of the sleeve.

An ATV jack may include an adjustable jack leg and an engagement member configured to engage a bracket disposed on an ATV to non-pneumatically lift the ATV to enable changing of a tire.

A roller system including a top roller, a middle roller, a split lower roller and a split workbench roller configured for a pump jack arranged for travelling up and down a pole, wherein the top roller includes flanges at both ends of the roller; wherein the split lower roller includes a pair of facing lower rollers, each of the pair of facing lower rollers having an outward tapered flange; and wherein the split workbench roller includes a pair of facing workbench rollers, each of the pair of facing workbench rollers having an outward tapered flange.

A hand-held jack has a main body, including a frame on a grip, the frame having a shaft hole passing through a first chamber and a second chamber therein, a jacking member being fixed to a front end of the frame; and a slow-down device. The slow-down device includes a swing seat pushed by the first spring and mounted in the second chamber; at least one shaft clamp and at least one restricting plate urged by a third spring that are disposed in a first accommodating groove and a second accommodating groove of the swing seat for clamping a lift shaft; and an eccentric push member having an eccentric portion resting on the restricting plate and a push portion. When a workpiece is lifted by the hand-held jack, the slow-down device lowers the workpiece slowly.

A hand-held jack has a main body, including a frame on a grip, the frame having a shaft hole passing through a first chamber and a second chamber therein, a jacking member being fixed to a front end of the frame; and a slow-down device. The slow-down device includes a swing seat pushed by the first spring and mounted in the second chamber; at least one shaft clamp and at least one restricting plate urged by a third spring that are disposed in a first accommodating groove and a second accommodating groove of the swing seat for clamping a lift shaft; and an eccentric push member having an eccentric portion resting on the restricting plate and a push portion. When a workpiece is lifted by the hand-held jack, the slow-down device lowers the workpiece slowly.

A safety link for linking a high-lift jack to a vehicle may include an upper bracket and a lower bracket. The upper bracket may include one or more slots for securing the link to a vehicle shackle tab. The lower bracket may include one or more slots for securing the link to a jack.

A jack screw locking device is provided. The jack screw locking device has a general L-shape defined by a key arm and a lock arm. The lock arm provides a lock slot and the key arm provides a key notch. The former is for operatively associating with a scissor jack's jack screw nut in a locked engagement when the key arm is slid between a fork portion of the scissor jack framing, thereby preventing rotation about torque axis of the jack screw nut. In conditions where the jack screw starts unwinding immediately upon removing the crank, the key notch can be used to engage the same jack screw nut in a holding position prior to the crank being removed, thereby temporarily holding the jack screw in order to effectuate the locked engagement via a second jack screw locking device.

A jack screw locking device is provided. The jack screw locking device has a general L-shape defined by a key arm and a lock arm. The lock arm provides a lock slot and the key arm provides a key notch. The former is for operatively associating with a scissor jack's jack screw nut in a locked engagement when the key arm is slid between a fork portion of the scissor jack framing, thereby preventing rotation about torque axis of the jack screw nut. In conditions where the jack screw starts unwinding immediately upon removing the crank, the key notch can be used to engage the same jack screw nut in a holding position prior to the crank being removed, thereby temporarily holding the jack screw in order to effectuate the locked engagement via a second jack screw locking device.

A central column allowing a 360 rotation on its central axis comprises mechanical safety locks and load sensors for safe operation in vertical and horizontal movements. The central rotating column may be part of a mounting and dismounting system for mining truck dump bodies and water truck bodies, providing two adjacent working areas. The lifting system for dump bodies of mining trucks and bodies of water trucks comprises a vertically adjustable mechanical lock; a spring-actuated automatic lock horizontally holding the column in position; an automatic rotation lock preventing the column from rotating while in operation; a toothed crown and pinion assembly integrated to the rotating base and allowing a 360 movement, and a load sensor preventing the horizontal movement of the column under load.

An engine cradle system including a first support having a lifting mechanism coupled thereto and configured to slide along the first support, the lifting mechanism having a cradle assembly coupled thereto, where the cradle assembly includes a panel with a plurality of apertures with at least one of the plurality of apertures configured to secure an engine cradle to the panel.