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US 4,357,994 AGranted
Hydraulic well equipment hoist
OwnerEllis C. Hallinventor
Life of this patent
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OwnerEllis C. Hallinventor
Estimating the term…
A vertically elongated frame is provided including pairs of opposite sides and each opposite side includes a pair of upstanding opposite side guides. First, second and third pairs of upper, intermediate and lower hydraulic cylinders are provided on each frame side and the lower portion of each upper cylinder lower portion is communicated with the upper portion of the next lower cylinder upper portion whereby fluid pressure in all of the cylinders is maintained equal and the cylinders may extend in sequence with the upper cylinders extending first, the intermediate cylinders extending second and the lower cylinders extending last. Further, the equalization of the fluid pressures within the cylinders also enables the cylinders to retract in sequence with the lower cylinders retracting first, the intermediate cylinders retracting second and the upper cylinders retracting third. With all of the interiors of the hydraulic cylinders communicated a single supply line may be provided to supply hydraulic fluid under pressure thereto and safety valves may be operatively associated with the various upper, intermediate and lower cylinders of automatically preventing the venting of hydraulic fluid therefrom in the event a hydraulic leak occurs in the main supply system to the cylinders.
A fluid pressure hoist including an upright frame having a pair of opposite sides, a pair of upstanding guides on each opposite side, at least two pairs of first upper and second lower vertically extendible hydraulic cylinders on each opposite side of said frame, each cylinder including relatively extendible tubular upper and lower telescopingly engaged portions, each opposite side including a first upper brace extending between the upper ends of the upper portions of the upper cylinders and guidingly engaged with said guides, a second brace extending between the upper ends of the lower portions of said upper cylinders as well as the upper ends of the upper portions of the lower cylinders and guidingly engaged with said guides, a third brace extending between the lower ends of the lower portions of the upper cylinders, a fourth brace extending between the upper ends of the lower portions of the lower cylinders, the upper ends of the second lower cylinder upper portions being in fluid communication with the lower ends of the upper cylinder lower portions, a third lowest pair of vertically extendible hydraulic cylinders on each opposite side of said frame, said fourth brace also extending between the upper ends of the upper portions of the third cylinders and guidingly engaged with the corresponding guides, a fifth brace extending between the lower ends of the lowest portions of the second cylinders, the upper ends of the third cylinder upper portions being in fluid communication with the lower ends of the second cylinder lower portions and means operative to selectively communicate said lower portions of said third cylinders with a source of fluid under pressure.
A fluid pressure hoist including an upright frame having a pair of opposite sides, each of said opposite sides including first upper, second intermediate and third lower hydraulic cylinders, each of said hydraulic cylinders including upper tubular piston rod and lower tubular cylinder portions, a lifting head connected between the upper ends of the piston rod portions of the upper cylinders, means providing fluid communication with the interiors of the lower ends of the lower cylinder portions of the upper cylinders with the interiors of the upper ends of the piston rod portions of the intermediate cylinders and means providing fluid communication with the lower ends of the interiors of the cylinder portions of the intermediate cylinders with the interiors of the upper end portions of the piston rod portions of the lower cylinders, means providing fluid communication with the interiors of the upper ends of the upper piston rod portions of the upper cylinders, first brace means interconnecting the upper ends of the upper cylinders and the upper ends of the piston rod portions of the intermediate cylinders and guidingly engaged with the corresponding side of said frame, second brace means interconnecting the upper ends of the intermediate cylinders and the upper ends of the piston rod portions of the lower cylinders and guidingly engaged with the corresponding side of said frame, and means operative to selectively communicate the lower cylinder portions of the lower cylinders with a source of fluid under pressure.
Dependencies are inferred from the claim text.