Abstract: A dual ratchet pawl jacking system, device, and method are presented for raising and/or lowering a platform bearing carriage along a vertical support. The ratchet pawls alternate supporting the weight of the carriage by engaging against a series of lugs on the vertical support. A first pawl is attached to the main frame of the carriage, and a second pawl is attached to a sub-carriage assembly that slides upward and downward within the carriage frame. A hydraulic jack applies a force upon the sub-carriage, causing the sub-carriage to move within the frame. The weight of the carriage is alternately borne by each pawl as the other pawl is relocated to a new lug. A pair of triggers is used to retract the first pawl and second pawl from the support. The triggers may be enabled to facilitate lowering the carriage, or disabled to facilitate raising the carriage.

Abstract: A dual ratchet pawl jacking system, device, and method are presented for raising and/or lowering a platform bearing carriage along a vertical support. The ratchet pawls alternate supporting the weight of the carriage by engaging against a series of lugs on the vertical support. A first pawl is attached to the main frame of the carriage, and a second pawl is attached to a sub-carriage assembly that slides upward and downward within the carriage frame. A hydraulic jack applies a force upon the sub-carriage, causing the sub-carriage to move within the frame. The weight of the carriage is alternately borne by each pawl as the other pawl is relocated to a new lug. A pair of triggers is used to retract the first pawl and second pawl from the support. The triggers may be enabled to facilitate lowering the carriage, or disabled to facilitate raising the carriage.

Abstract: An extension rod unit includes an outer tube with an inner tube retractably inserted thereto and a ratchet unit is connected to the open top of the outer tube. The ratchet unit includes a connection member and a lever. The connection member includes two side panels and each have a first lug extending therefrom. The lever has two second lugs and the shaft extends through the first and second lugs so as to pivotably connect the lever to the connection member. Two ratchet gears are located between two sets of first and second lugs. A slot is defined axially through the shaft. A driving member has a first end fixed to the fixing part and a second of the driving member extends through the slot of the shaft and is located beyond the outer tube. By pivoting the lever, the inner tube can be moved relative to the outer tube.

Abstract: A locking device installed in a cargo support to lock a retractable tube, including a holder frame fastened to the outer tube of the retractable tube, a rack moved in a longitudinal sliding way defined between two parallel lugs of the holder frame, a driving lever pivoted to the holder frame for moving the rack, and a locking block pivoted to the holder frame and retained by a spring to lock the driving lever, wherein a L-shaped locating plate is mounted in the holder frame for the positioning of the outer tube of the retractable tube, having a round hole on a transverse section thereof through which the inner tube is inserted into the outer tube, two stop flanges bilaterally extended from a longitudinal section thereof and respectively engaged with respective end notches on the holder frame, and a lug extended from one stop flange and fastened to a lug at the holder frame; the holder frame and the locking block are respectively made of iron.

Abstract: The self-locking chock system has a plurality of pawl cams grouped in a sequential alignment along a support member that is substantially parallel with a leg rack of a jack-up rig unit. Each of the cams is pivoted about a pivot axis that is on the common alignment axis of the support member, and is forced to ride upon the leg rack by a center of gravity located outwardly from the alignment axis on the side opposite that which rides on the leg rack. The cam profile is adapted to ride along the leg rack profile when the relative motion between the leg rack and the support member is in a first direction. When the relative motion is in a direction opposite to the first direction, the cam profile complements the leg-rack profile and under the weighted urging of the cam, the cam profile engages the leg-rack profile and enters into a positive, self-locking engagement that restrains further relative motion between the leg rack and the support member at least in the opposite direction.

Abstract: A chain jack utilizing two chains is operated by alternately transferring e chain load from latches incorporated within an upper latch assembly to latches incorporated within a lower latch assembly while moving the upper and lower latch assemblies away from and toward each other by alternate extension and retraction of a hydraulic ram to cause relative movement between the chain and the lower latch assembly. Actuation of the latch mechanism is controlled by hydraulic connection to a pair of four-way valves operated by a control piston having followers from the four-way valves engageable thereon. The control piston is disposed to move with the upper latch assembly while the followers are rigidly affixed to the lower latch assembly. Thus, the engagement and disengagement of the latch mechanisms with the chains are synchronized by the relative movement between the lower and upper latch assemblies.

Abstract: Support leg construction for tank portable bridges including a housing or support leg formed by respective inner and outer sleeve members. A longitudinally movable stanchion is guided intermediate the inner and outer sleeves. A hydraulically operable piston member is disposed in the inner sleeve and includes hydraulically operable detent spring ring locking means for selectively locking the piston to the stanchion. A further hydraulically operable spring-ring locking mechanism is fixedly disposed at the open end of the inner sleeve for selectively locking the stanchion in position with respect to the inner and outer sleeves.