Jack with Two Masts

摘要

A jack for lifting segments of a structure includes a pair of masts, a mast base, a mast cap, a hydraulic ram, a bottom bracket and a shuttle. The masts are identical and upright with a plurality of evenly spaced holes. The mast base supports the mast and the mast cap receives the upper ends of the masts and maintains the masts in a parallel, relationship. The hydraulic ram moves between a retracted position and an extended position with a stroke distance which is significantly less than the mast height. The bottom bracket is removably pinned to the masts and receives and supports the lower end of the hydraulic ram. The shuttle receives the upper end of the hydraulic ram. The bottom bracket and shuttle, when not pinned to the masts, can slide vertically up the masts. The shuttle includes features for connecting to a segment of a structure.

主权项

1. A jack for raising a ring segment of a cylindrical structure on a foundation pad, comprising:
(a) a pair of upright masts, each mast extending from a lower end to an upper end, each mast presenting a plurality of evenly spaced holes, (b) a mast base operable for receiving the lower ends of the masts and securing the lower ends in a side by side spaced apart relationship, (c) a mast cap operable for receiving the upper ends of the masts and securing the upper ends of the masts in a side by side, spaced apart relationship, (d) a hydraulic ram having a lower end and an upper end, the hydraulic ram operable for movement between a retracted position and an extended position, when in the extended position, the distance between the lower end and the upper end of the hydraulic ram being greater by a stroke distance than the distance between the lower and upper ends of the hydraulic ram when in the retracted, the stroke distance being substantially less than the length of the masts, (f) a bottom bracket which connects between the masts and which is adapted to be removably pinned to corresponding pairs of the evenly spaced holes of each mast, the bottom bracket operable to receive and support the lower end of the hydraulic ram such that the lower end of the hydraulic ram is positioned generally between the masts, the bottom bracket also operable for sliding vertically when the bottom bracket is not pinned to the masts, (g) a shuttle which connects between the masts and which is adapted to be removably pinned to holes in each mast, the shuttle operable to receive the upper end of the hydraulic ram such that the upper end of the hydraulic ram is positioned generally between the masts, the shuttle also operable for sliding vertically when the shuttle is not pinned to the masts, the shuttle having features for connecting to a segment of a structure, whereby when the bottom bracket is secured to the masts and the shuttle is not pinned to the masts, a segment of structure connected to the shuttle can be raised by extending the hydraulic ram from the retracted position toward the extended position, and whereby, when the raised shuttle is pinned to the masts and the bottom bracket is unpinned, the bottom bracket can be lifted toward the shuttle by contracting the hydraulic ram toward the retracted position, and whereby, after pinning the lifted bottom bracket to the masts and unpinning the shuttle, the shuttle and the segment of structure attached to the shuttle may be raised again by again extending the hydraulic ram toward the extended position, and whereby these steps may be repeated until the shuttle has reached the top of the masts.