Hydropneumatic Cylinders

Pneumohydraulics
Hydro-pneumatic cylinder is the name of the new generation of power cylinders for press and plant engineering applications. The cylinder is used when high forces are required, for example for punching, splitting, pressing, stamping, molding, riveting, clamping, compressing or spot welding. In power stroke mode users are provided with many times the force of a comparable conventional pneumatic cylinder with the same air consumption.
Hydro-pneumatic cylinder is designed in the same way as a double-acting pneumatic cylinder and is also controlled in the same manner. It is equipped with a pneumohydraulic pressure booster which generates a power stroke when necessary depending on the counterforce. The power cylinder can be operated directly from the compressed air network by means of a pneumatic valve.

Simple operation
With its clever design the Hydro-pneumatic cylinder can be controlled in the same manner as a double-acting pneumatic cylinder. In contrast to conventional power cylinders, switchover from fast stroke to power stroke takes only approx. 0.05 seconds, without venting noises and without requiring an additional valve.

Tool-conserving operation
Positioning of the operating piston with the tool on the workpiece is extremely precise and therefore protects the tool, as only the surface of the piston rod is effective due to the design of the device with its freely-actuated operating piston.

With a piston rod diameter of 20mm and a nominal pressure of 6 bar, for example, this contact force is 90kg; Switchover from fast stroke to power stroke is therefore initiated at a counterforce of 90kg. The operating piston is hydraulically damped when it is pushed into the high-pressure sleeve and moves smoothly without jerking.

Switchover from fast stroke to power stroke is unnoticeable. While conventional pneumatic cylinders, shoot through" at full power, for example during punching operations, the Hydro-pneumatic cylinder gently makes contact with the workpiece with a low force and then builds up the full power.
Machining workpieces with varying heights does not pose a problem, as the power stroke is only generated when a corresponding counterforce is met at any position throughout the overall stroke.