Tensioning devices
AssigneePilgrim Engineering Development Limited
InventorThomas W. Bunyan
Life of this patent
Estimating the term…
Abstract
A hydraulic nut or washer or bolt head comprises piston means let into the recessed end-face of a body. Means for applying hydraulic pressure to a chamber or chambers behind the body are provided to urge the piston means in a direction which leads out of the end face. The piston means has an overall dimension in a first transverse direction which is less than the least possible overall dimension of an annular piston giving the same piston face area and having an overall dimension in another transverse direction, at right angles to the first, which is less than the least overall major dimension for a pair of opposed circular pistons giving the same piston face area. A sealing member comprising a layer of moulded deformable substantially incompressible material on a former is provided in the chamber to contain the hydraulic fluid.
Claims34
A tensioning device comprising a body having piston means housed in a recessed end-face of the body and movable parallel to an axle extending through the body, and means for supplying hydraulic fluid behind the piston means to urge the piston means in an axial direction which leads out through said end-face, said piston means having two piston face areas, one on each of a transverse plane of the body containing said axis, said piston and face areas of said piston means having a concavely curved inner side-face with respect to said axis and an extended convexly curved outer side-face, the outer side-face being dimensioned such that the piston means has an overall transverse dimension less than the least possible overall diameter of an annular piston giving the same piston face area, and an overall longitudinal dimension less than the least possible for a pair of opposed circular pistons giving the same piston face area, said two piston face areas of said piston means having centroids collinear with said axis of the body, the centroids being spaced from said axis by respective distances which are inversely proportional to the areas of the respective pistons face areas.
A tensioning device comprising a body having piston means housed in a recessed end-face of the body and movable parallel to an axis extending through the body, and means for supplying hydraulic fluid behind the piston means to urge the piston means in an axial direction which leads out through said end-face, said piston means having two piston face areas, one on each side of a transverse plane of the body containing said axis, said piston and face areas of said piston means having a curved substantially circular inner side-face with respect to said axis and an extended curve substantially oval-shaped outer side-face, the outer side-face being dimensioned such that the piston means has an overall transverse dimension less than the least possible overall diameter of an annular piston giving the same piston face area, and an overall longitudinal dimension less than the least possible for a pair of opposed circular pistons giving the same piston face area, said two piston face areas of said piston means having centroids collinear with said axis of the body, the centroids being spaced from said axis by respective distances which are inversely proportional to the areas of the respective pistons face areas.
Dependencies are inferred from the claim text.