| 摘要 |
Hydraulic press apparatus with a lower plate (1) and an upper moving plate (2), a hollow cylinder (7) under the lower plate (1), a guide column (10) joined on top to the upper plate (2) and with a lower end portion forming the rod of a piston (13) adapted to slide in the hollow cylinder (7), an aperture (15) in the side surface of the hollow cylinder adapted to connect the inner volume existing above the piston (13) with means (17) that are adapted to apply a hydraulic pressure within said inner volume. The guide column (10) is provided with a cylindrical cavity (18) filled with oil, extending all along the interior of the piston (13) and coming out of the latter from the lower portion thereof. There is provided a plunger-type piston that is arranged to slide within said cylindrical cavity and is provided with an upper cylindrical portion (20) that plugs said inner cavity, and with a lower portion (21) having a smaller diameter. A through-bore (22) connects the inner cylindrical cavity (18) with said inner volume (16) when the upper cylindrical portion (20) of the plunger-type piston is displaced under the level of said through-bore. |
