摘要:
Jack safety device, having a rotation key integral with a pressing spring, a hollow-set key lid, and a spanner fitting the spanner onto a hydraulic tank incorporating a camming bearing surface on the spanner so as to move the key into grooves on the hydraulic jack stem in one position of the spanner and lift the key out of the grooves in another position of the spanner.
摘要:
A double-acting hydraulic jack, comprising a hollow piston reciprocable in a surrounding cylinder, includes a tubular shaft extending axially inside and carrying a nut of the circulating-ball type which coacts with a screw coaxially disposed in that shaft. The screw is rigid with the piston whereby an axial displacement of the latter is translated into a rotation of the shaft; a toothed wheel on the shaft, engaged by a spring-loaded detent, acts as a one-way brake enabling such rotation only in one direction and blocking it in the opposite direction unless the detent is withdrawn by a hydraulic servomotor which is pressurized concurrently with the admission of fluid to the cylinder tending to displace the piston in the normally blocked direction. In the case of a double-acting jack, two oppositely effective one-way brakes--possibly including a single toothed wheel on the tubular shaft--normally prevent a displacement in either direction but are respectively deactivated by the admission of fluid into the cylinder at one or the other end thereof.
摘要:
A mechanical locking outrigger hydraulic jack for an outrigger assembly for use with cranes and the like includes vertically disposed cylindrical fixed and movable members, the fixed member being secured to a vertically disposed external sleeve. A variable extension chamber is defined by the interiors of the fixed and movable members. A variable retraction chamber is defined exteriorly of the fixed member and interiorly of the movable member. Valve means permit selective raising and lowering of the movable member. A locking nut threadedly engages the threaded exterior of the movable member and is engagable with an external surface of the locking sleeve to mechanically lock the movable member in an extended, lowered position.
摘要:
A hydraulic jack comprising a cylinder, a piston slidable relative to the cylinder, pump means to supply pressurized fluid to the base of the piston, a seal between the piston and the cylinder, means for limiting the stroke of the piston in the cylinder, said means comprising a ring carried by the piston and arranged to expand into a groove in the cylinder wall when the piston reaches the end of its permitted travel, and means for selectively de-activating said stroke limiting means, in order to allow removal of the piston from the cylinder to renew the seal.
摘要:
A double-acting rotary hydraulic jack having two jack compartments, comprising a rotary hydraulic joint for the supply of hydraulic liquid to and the evacuation of hydraulic liquid from the compartments. The two compartments of the jack each communicate with at least one axial boring in a rotary part of the jack which is not axially movable. In this boring a movable piston bears against the head of a guide rod for a spring which itself bears against the rotary part of the jack. The ends of the rods, externally of the borings, are secured to a member coaxial with the jack, for example a sleeve, whose axial position is monitored by a displacement detector, so as to give an indication of the working pressure in the active jack compartment.
摘要:
A resilient leg for a stool includes a cylinder normally attached to the seat of the stool and a piston rod attached to a piston in the cylinder and normally attached to the stool base. The two compartments in the cylinder axially separated by the piston are filled with compressed gas and may be connected by a manually operated valve. They are also connected automatically by recesses in the axial inner wall of the cylinder when the piston approaches one of the radial end walls of the cylinder. A helical spring then abuttingly engages the end wall and the piston rod to impede further movement of the piston toward the end wall with a force greater than that exerted by the gas in the absence of the recesses.
摘要:
A rolling hydraulic auto jack has a shaft which telescopes to raise and lower an auto. The invention provides a metal channel or block which fits around the shaft to preclude a telescoping retraction thereof. This channel or block is a safety stop which keeps the jack from inadvertently lowering the auto, even if the hydraulic system fails.