A forming apparatus includes: a slide on which one of a pair of dies is mounted and which has a hole portion and can advance and retreat in an advancing and retreating direction; a die clamping force generating unit having a piston movable in the advancing and retreating direction and generating a die clamping force; a slide driving unit advancing and retreating the slide in the advancing and retreating direction; and a die clamping force transmitting unit which transmits the die clamping force from the die clamping force generating unit to the slide and includes a force transmitting body transmitting the die clamping force from the piston to the slide and movable between a first position to prevent the piston from entering the hole portion and a second position to allow the piston to enter the hole portion, and a force transmitting body driving unit moving the force transmitting body.

Disclosed is a piston-cylinder assembly of a hydraulic press, which includes a basic cylinder and a first and second piston. A ring cylinder is formed above the basic cylinder as a continuation of the cylinder structure. The first piston is located inside the basic cylinder in the bottom part of the basic cylinder and the second piston is located above the first piston in the top part of the cylinder structure. The piston-cylinder assembly has a first hydraulic fluid space below the first piston and a second hydraulic fluid space below the second piston and the piston-cylinder assembly includes a unified hydraulic fluid channel in flow connection to the first hydraulic fluid space in order to provide a pressure effect in the first piston and to the second hydraulic fluid space in order to provide a pressure effect in the second piston.

Disclosed is a piston-cylinder assembly of a hydraulic press, which includes a basic cylinder and a first and second piston. A ring cylinder is formed above the basic cylinder as a continuation of the cylinder structure. The first piston is located inside the basic cylinder in the bottom part of the basic cylinder and the second piston is located above the first piston in the top part of the cylinder structure. The piston-cylinder assembly has a first hydraulic fluid space below the first piston and a second hydraulic fluid space below the second piston and the piston-cylinder assembly includes a unified hydraulic fluid channel in flow connection to the first hydraulic fluid space in order to provide a pressure effect in the first piston and to the second hydraulic fluid space in order to provide a pressure effect in the second piston.

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.

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.

A hydraulic press includes a workbench having four corners provided with uprights. The uprights are arranged in two rows front and rear, and the tops of the uprights in each row are connected by an upper beam extending in a left-right direction. Tie rods are inserted in the front and rear of each upright. The tie rods each have an upper end protruding from the top of the upper beam and fixed to the upper beam by an upper nut and a lower end protruding from the bottom of the workbench and fixed to the workbench by a lower nut. A central cylinder is provided at the center of the upper beam. Side cylinders are symmetrically arranged on the left and right of the central cylinder. The lower ends of plungers of the central cylinder and the side cylinders are fixedly connected to a top of a slider.

A hydraulic press includes a workbench having four corners provided with uprights. The uprights are arranged in two rows front and rear, and the tops of the uprights in each row are connected by an upper beam extending in a left-right direction. Tie rods are inserted in the front and rear of each upright. The tie rods each have an upper end protruding from the top of the upper beam and fixed to the upper beam by an upper nut and a lower end protruding from the bottom of the workbench and fixed to the workbench by a lower nut. A central cylinder is provided at the center of the upper beam. Side cylinders are symmetrically arranged on the left and right of the central cylinder. The lower ends of plungers of the central cylinder and the side cylinders are fixedly connected to a top of a slider.

The invention relates to a precision blanking press including a top, a base and tie rods and columns that operatively connect the top and the base. The precision blanking press has a press frame with a high stiffness, low mass and simple design, the press allowing the transfer of higher cutting forces during fine blanking while safely eliminating axial play between adjustment elements and at the same time improving the operational safety.

The invention relates to a precision blanking press including a top, a base and tie rods and columns that operatively connect the top and the base. The precision blanking press has a press frame with a high stiffness, low mass and simple design, the press allowing the transfer of higher cutting forces during fine blanking while safely eliminating axial play between adjustment elements and at the same time improving the operational safety.

A linear actuator is disclosed. The linear actuator comprises a cylinder portion and a base portion. The cylinder portion comprises a housing defining internally a compression chamber for containing a fluid and comprising a piston assembly that can reciprocate within the compression chamber. The housing further defines a cylinder port in fluid communication with said compression chamber. The base portion defines a first base port and a second base port and a passage extending therebetween fluidly communicating the first base port with the second base port, and comprises valve means operable to control the flow of fluid through the second base port, in which the valve means is actuatable between an open condition in which the flow of fluid through the second base port is permitted, and a closed condition in which the flow of fluid through the second base port is substantially prevented. The cylinder portion is releasably engageable with the base portion such that the cylinder portion and the base portion may be arranged in an engaged condition in which engaged condition the cylinder port and the second base port are in fluid communication.