Hollow cylinders

Hollow-piston cylinders are especially suitable for clamping workpieces that have a through hole or opening.

The piston has a through hole with an internal thread.
In connection with a standard tie rod and C-washer combination a variety of applications is possible (see application examples).
After the workpiece has been inserted and centred by hand, the C-washer can be pushed onto the tie rod and then clamped hydraulically.
Compared to mechanical clamping with clamping screws this has significant advantages:

• The clamping force can be hydraulically adjusted with precision and high repetitive accuracy
• The operator can fully concentrate on the correct position of the workpiece
• A significant time saving

Hollow-piston cylinders in combination with push-pull bolt and “C”-washer can be used advantageously in many cases to clamp workpieces with centre openings.

 On the shown machine table, the workpiece is clamped with a hollow-piston cylinder and additionally supported with a work support, controlled by a sequence valve.
The support plunger of the work support is retracted in off-position to facilitate workpiece loading. Contact is effected by means of spring force. The savings in workpiece exchange time, compared to a mechanical clamping system amounts to 58%.

This clamping fixture is for milling operation on a light extruded rail. Workholding by means of hollow-piston cylinders in individual clamping stations mounted on a base plate. Positioning and support of the rail is effected with two longitudinal members matching the cross section of the rail.