Patent GB-189805135-A (GB)
Title: Improvements in Hydraulic Presses for Forging and Analogous Purposes.
Inventor: FIELDING JOHN
Filed: 1898-03-02
Granted: 1899-01-28
Abstract: 5135. Fielding, J. March 2. Forging; reveting; punching; hydraulic pressure apparatus for actuating machines by.-The invention relates to hydraulic forging-presses, and to other presses or machines such as riveting and punching machines. The valves are arranged so as to admit high-pressure water automatically to the working cylinder of the press immediately the motion of the ram is arrested by coming in contact with the work. In the arrangement shown in Fig. 1, the ram of the press 1 descends by its own weight, water being admitted to the cylinder from a supply tank by pipes 23, 19, and the mitre valve 8. The ram can be lifted by means of plungers in cylinders 3, 3, controlled by a working-valve 4, which is connected to an accumulator by the pipe 5. The exhaust 7 from the valve 4 is connected to the pipe 23 and the supply tank. The final pressure on the ram of the press is supplied from an intensifier worked either by steam, air, or hydraulic pressure. The intensifier shown is intended to be worked by steam, the supply and exhaust being regulated by a piston valve 29, controlled by a piston 37, in a cylinder 36, which is connected to the cylinders 3, 3. When the press is descending, the pressure in the cylinders 3, 3, due to the weight of the ram &c., is sufficient to keep the valve 29 closed to steam as shown, but when this pressure is relieved by the ram coming into contact with its work the steam pushes down the valve 29 and enters the cylinder 24. The hydraulic cylinder 13 of the intensifier is supplied with water from an accumulator by a pipe 39 and a non-return valve 40, and communicates with the press cylinder through a valve 12 which is only allowed to open when the pressure in the cylinders 3, 3 is reduced by the ram coming into contact with the work. The valve 12, which is shown to a larger scale in Fig. 2, is ordinarily kept closed by means of the pressure in the cylinders 3, 3, a connection being made by pipes 10 and 21 to the upper side of a piston 14 acting upon the valve 12. When the press is making its return stroke, the valve 8 is held open by a controlling-cylinder 9 connected by the pipe 10 with the cylinders 3, 3. The steam valve 29 is made without rings or packing, but is provided with bevelled surfaces at each end which come into contact with bevelled seatings in the valve casing 28. The piston 25 is provided with a boss 35 which nearly closes the exhaust port 34 and causes cushioning on the return stroke. In machines in which the weight of the ram is not sufficient to carry it through the idle part of the stroke, a doubleacting auxiliary cylinder is used, to move the ram to and fro. Such a machine is described with automatic valves for working by accumulator pressure only, without intensifier. In another modification, a valve is used such as is described in Specification No. 3144, A.D. 1898, the ram being worked by accumulator pressure and also by an intensifier, and the valve making the change automatically from the one to the other. Two intensifiers giving different pressure may also be arranged to come into operation one after the other.