Spring Clamping Cylinders

Hydro-Mechanical Spring Clamping System

The piston assembly (pulling or pushing version) is subjected alternatively to the disk spring force or hydraulic pressure. This means that the disk spring packet is compressed more with increasing pressure. The hydraulic pressure is required only for the release stroke of the elements whereby the pull stud/pressure piece is released.

This system ensures a very high factor of safety since the clamping force generated is independent from the oil pressure and from pressure loss due to leakage. The full clamping force remains constant at all times.

The short operating cycle times of the hydraulic power pack additionally save on costs and make it more economical. The spring clamping cylinders of the series ZSF and ZDF are robust and reliable elements which can be used in all applications where moveable machine parts (e.g. fixtures, dies etc.) need to be clamped or locked into position. They are also used in workpiece and tool clamping operations.

Principle of Operation

The piston (push or pull) is subjected alternately to disc spring force or the hydraulic pressure. This means, that as the spring assembly is pressed together with increasing pressure, the spring force increases. At setting pressure, the appropriate nominal clamping force is achieved as reaction force of the disc spring assembly. For release (push or pull), a higher hydraulic pressure is required, which is proportional to the release stroke up to a maximum value.

The appropriate pressure values can be found in the tables. With spring clamping cylinders, a clamping bolt or pull stud is screwed into the threaded bore of the piston adjusted and secured (on request also supplied as one piece). The required hydraulic assembly should be equipped with a pressure limiting valve, a switching magnetic valve, a pressure gauge and a pressure switch unit.