A percussion unit for a rotary hammer and/or percussion hammer includes a control unit that is configured for open-loop and/or closed loop control of a pneumatic percussion mechanism. In at least one operating state in which the control unit changes from an idle mode to a percussion mode, the control unit is configured to adjust at least one operating parameter temporarily to a starting value.

A percussion unit for a rotary hammer and/or percussion hammer includes a control unit that is configured for open-loop and/or closed loop control of a pneumatic percussion mechanism. In at least one operating state in which the control unit changes from an idle mode to a percussion mode, the control unit is configured to adjust at least one operating parameter temporarily to a starting value.

An electrohydraulic drive unit of a machine tool having a tool that can be moved up and down is provided and comprises a double-acting hydraulic cylinder-piston arrangement oriented in upright manner and having a piston projecting downwardly from the cylinder and being coupled with the tool, a valve block flanged to the cylinder at the upper end region thereof and having a servo suction valve, a hydraulic-fluid reservoir flanged to the valve block at a first hydraulic interface and a motor-pump unit having an electric motor and a hydraulic pump driven thereby and flanged to the valve block at a second hydraulic interface. A suction line, extends from the first hydraulic interface to the second hydraulic interface through the valve block.

An electrohydraulic drive unit of a machine tool having a tool that can be moved up and down is provided and comprises a double-acting hydraulic cylinder-piston arrangement oriented in upright manner and having a piston projecting downwardly from the cylinder and being coupled with the tool, a valve block flanged to the cylinder at the upper end region thereof and having a servo suction valve, a hydraulic-fluid reservoir flanged to the valve block at a first hydraulic interface and a motor-pump unit having an electric motor and a hydraulic pump driven thereby and flanged to the valve block at a second hydraulic interface. A suction line, extends from the first hydraulic interface to the second hydraulic interface through the valve block.

An improved electro-hydraulic clinching system involves generating, through a high potential electric shock, a forceful wave in a fluid such as water, and applying the force of the wave to a sheet of metal. The force of the wave results in deforming the sheet and making the sheet material move through a hole in a second sheet adjacent to the first sheet, thus joining the two sheets. In an alternative implementation, in which neither sheet includes an opening, the force of the wave moves both sheets simultaneously, thereby causing them to join together at the point of impact.

An improved electro-hydraulic clinching system involves generating, through a high potential electric shock, a forceful wave in a fluid such as water, and applying the force of the wave to a sheet of metal. The force of the wave results in deforming the sheet and making the sheet material move through a hole in a second sheet adjacent to the first sheet, thus joining the two sheets. In an alternative implementation, in which neither sheet includes an opening, the force of the wave moves both sheets simultaneously, thereby causing them to join together at the point of impact.

An electrohydraulic drive unit of a machine tool having a tool that can be moved up and down is provided and comprises a double-acting hydraulic cylinder-piston arrangement oriented in upright manner and having a piston projecting downwardly from the cylinder and being coupled with the tool, a valve block flanged to the cylinder at the upper end region thereof and having a servo suction valve, a hydraulic-fluid reservoir flanged to the valve block at a first hydraulic interface and a motor-pump unit having an electric motor and a hydraulic pump driven thereby and flanged to the valve block at a second hydraulic interface. A suction line, extends from the first hydraulic interface to the second hydraulic interface through the valve block.

An electrohydraulic drive unit of a machine tool having a tool that can be moved up and down is provided and comprises a double-acting hydraulic cylinder-piston arrangement oriented in upright manner and having a piston projecting downwardly from the cylinder and being coupled with the tool, a valve block flanged to the cylinder at the upper end region thereof and having a servo suction valve, a hydraulic-fluid reservoir flanged to the valve block at a first hydraulic interface and a motor-pump unit having an electric motor and a hydraulic pump driven thereby and flanged to the valve block at a second hydraulic interface. A suction line, extends from the first hydraulic interface to the second hydraulic interface through the valve block.

The present application provides a chamfer removing device for wheels. The device may be used for removing a bolt hole chamfer on flange side of back cavity of a wheel in hub machining process. Drill bits are spaced a certain height from the flange side of the wheel by adjusting the relative height of an external thread guiding sleeve in an internal thread guiding sleeve, a motor and gears drive the drill bits to rotate, and a cylinder and a sliding box drive the drill bits to move up and down so as to realize chamfer removing function.

There is provided a press machine which can apply a large compression force to a mold as well as impart smooth vibration only in a rectilinear advancing direction to the mold, and thereby can improve the press-formability. A main slide and a sub-slide constitute a slide and at the same time a cylinder-piston mechanism. During press-forming, a compression force is transmitted to the sub-slide (an upper mold) through hydraulic pressure applied interlockingly with driving of the main slide, and the sub-slide is vibrated with the hydraulic pressure being periodically changed. Favorable press-forming can be performed even under relatively difficult press-forming conditions, by controlling the vibration such that a vibration frequency of the sub-slide (the upper mold) becomes 9 Hz or higher but 33.3 Hz or lower and a vibration amplitude of the sub-slide becomes 0.05 mm or larger but 0.5 mm or smaller.