Abstract: A pressurized hydraulic fluid actuated coupling assembly for detachably coupling to an element. The assembly has first and second concentric walls secured together at the ends. The second wall is adapted for engaging the element. One of the walls has grooves defining corresponding recesses between the first and second walls. Ridges on such one wall are defined between adjacent recesses. Means is provided for introducing hydraulic fluid into the recesses. Means is provided for varying the pressure of the hydraulic fluid such that in the absence of fluid pressure, the ridges on the one wall are in contact with the other wall and upon pressurization of the fluid the second wall moves away from the first wall such that the second wall rigidly couples to the element and such that the ridges are spaced a predetermined distance from the other wall.

Abstract: A swivel joint comprises a journal fitted in a hole. The journal is conical and axially formlocked in the hole. A working chamber is arranged behind one of the mantle surfaces of the hole and the journal. The chamber has an integral flexible wall defining one of said surfaces. When hydraulic pressure is applied to the chamber, the flexible wall expands the journal is centered in the hole and locked against rotation, and the journal end engages the hole bottom.

Abstract: A sealing device in a cylindrical or annular working chamber in hydraulic mechanisms consists of a disk or plug formed as a sealing ring holder and from such a deformable material that by the action of increasing hydraulic fluid pressure the material radially expands into completely sealingly contact with the chamber. The disk or plug is provided with a sealing ring for performing the sealing function before said pressure increase.