A method of processing a material by use of high kinetic energy comprises a piston driven from a start position by a hydraulic system pressure by a drive chamber, by only one stroke, to transfer high kinetic energy to a blank/tool to be processed, whereafter there is a risk that a rebound of the piston will occur, so a step is taken in connection with said stroke performed, to prevent said piston from making a rebound with an essential content of kinetic energy to avoid negative effects as a result, whereafter the piston is returned to said start position by means of a second chamber, wherein a valve means closes the driving connection between the system pressure and the piston, the valve means is controlled by a pilot valve controlling the entire striking progress, and the second chamber is pressurized with the system pressure during the entire striking progress.

The present invention relates, in particular, to a forging hammer comprising a striker and a hydraulic linear drive that is coupled to the striker and is designed to drive the striker, which drive comprises a hydraulic circuit having a servo-motor hydro pump, a hydraulic cylinder, in particular a differential cylinder, which is fluidically connected downstream of the hydro pump via a directional valve module, and a servo-motor hydro generator, which is fluidically connected downstream of the hydraulic cylinder via the directional valve module, and comprising in addition a control unit configured at least for the simultaneous control of the hydro pump, the hydro generator and the directional valve module.

The present invention relates, in particular, to a forging hammer comprising a striker and a hydraulic linear drive that is coupled to the striker and is designed to drive the striker, which drive comprises a hydraulic circuit having a servo-motor hydro pump, a hydraulic cylinder, in particular a differential cylinder, which is fluidically connected downstream of the hydro pump via a directional valve module, and a servo-motor hydro generator, which is fluidically connected downstream of the hydraulic cylinder via the directional valve module, and comprising in addition a control unit configured at least for the simultaneous control of the hydro pump, the hydro generator and the directional valve module.

A part of kinetic energy during lowering of a slide of a press machine is converted into oil hydraulic energy by a first oil hydraulic cylinder, and the converted oil hydraulic energy (hydraulic oil having boosted first system pressure) is stored in a first accumulator. The hydraulic oil having the first system pressure stored in the first accumulator is discharged in knockout process, a second oil hydraulic cylinder that functions as a knockout cylinder is raised to perform knockout operation of a product worked by the press machine. Consequently, it is possible to perform knockout operation without using a dedicated driving source such as an oil pressure source and an air pressure source, and provide a low-cost hydraulic knockout device.

A part of kinetic energy during lowering of a slide of a press machine is converted into oil hydraulic energy by a first oil hydraulic cylinder, and the converted oil hydraulic energy (hydraulic oil having boosted first system pressure) is stored in a first accumulator. The hydraulic oil having the first system pressure stored in the first accumulator is discharged in knockout process, a second oil hydraulic cylinder that functions as a knockout cylinder is raised to perform knockout operation of a product worked by the press machine. Consequently, it is possible to perform knockout operation without using a dedicated driving source such as an oil pressure source and an air pressure source, and provide a low-cost hydraulic knockout device.

A hydraulic forging press machine and a control method, whereby surging of the forging load or dead zones where the forging speed goes to zero is suppressed, and forging is performed with high precision throughout a wider range than the prior art, from low to high load. Pressure cylinders have a main pressure cylinder configured so working fluid is supplied during forging, and secondary pressure cylinders are configured so supplying and stopping of the supply of working fluid thereto are switched in response to the forging load, head-side hydraulic chambers of the secondary pressure cylinders being connected to a head-side hydraulic chamber of the main pressure cylinder via electromagnetic switching valves. Only the main pressure cylinder is used until the forging load exceeds a set load, and the number of secondary pressure cylinders used is sequentially increased as the forging load increases after the forging load exceeds the set load.

A hydraulic forging press machine and a control method, whereby surging of the forging load or dead zones where the forging speed goes to zero is suppressed, and forging is performed with high precision throughout a wider range than the prior art, from low to high load. Pressure cylinders have a main pressure cylinder configured so working fluid is supplied during forging, and secondary pressure cylinders are configured so supplying and stopping of the supply of working fluid thereto are switched in response to the forging load, head-side hydraulic chambers of the secondary pressure cylinders being connected to a head-side hydraulic chamber of the main pressure cylinder via electromagnetic switching valves. Only the main pressure cylinder is used until the forging load exceeds a set load, and the number of secondary pressure cylinders used is sequentially increased as the forging load increases after the forging load exceeds the set load.

Provided are an efficient energy-saving return cylinder of a hydraulic press and a working method thereof. The efficient energy-saving return cylinder of a hydraulic press comprises a plurality of single-rod return hydraulic cylinders symmetrically distributed at two sides of a main hydraulic cylinder of the hydraulic press, the plurality of single-rod return hydraulic cylinders are divided into several groups, each of the groups consisting of one balancing cylinder and one driving cylinder; a rod chamber of the balancing cylinder is communicated with an accumulator, the pressurized oil in the accumulator is filled into an oil chamber of the balancing cylinder, so that the balancing cylinder balances the weight of a walking beam and a working part of the walking beam; the driving cylinder is differentially connected; in the process of neutral-stroke-rapid-descending and ascending-returning of the walking beam and the working part of the walking beam.

A hydraulic forging machine and a method for replacing an upper anvil block thereof are disclosed. The hydraulic forging machine includes locking hydraulic cylinder that is fixed to a movable beam of the hydraulic forging machine when the hydraulic forging machine is in operation. The locking hydraulic cylinder is configured to provide a locking-unlocking function between an upper anvil block of the hydraulic forging machine and the movable beam. The locking hydraulic cylinder has its hydraulic power source supplied from a main hydraulic cylinder or a return hydraulic cylinder, which is also fixed to the movable beam. The present disclosure not only enables an oil supply circuit for the locking hydraulic cylinder to move together with the movable beam, but also simplifies the oil supply circuit for the locking hydraulic cylinder, resulting in an improved reliability of the hydraulic forging machine.

A hydraulic forging machine and a method for replacing an upper anvil block thereof are disclosed. The hydraulic forging machine includes locking hydraulic cylinder that is fixed to a movable beam of the hydraulic forging machine when the hydraulic forging machine is in operation. The locking hydraulic cylinder is configured to provide a locking-unlocking function between an upper anvil block of the hydraulic forging machine and the movable beam. The locking hydraulic cylinder has its hydraulic power source supplied from a main hydraulic cylinder or a return hydraulic cylinder, which is also fixed to the movable beam. The present disclosure not only enables an oil supply circuit for the locking hydraulic cylinder to move together with the movable beam, but also simplifies the oil supply circuit for the locking hydraulic cylinder, resulting in an improved reliability of the hydraulic forging machine.