Pit Federn GmbH - Petersmann Innovative Technik

The PIT Liquid Spring Technology uses a highly compressible fluid, a silicone oil. Under hydrostatic pressure this silcone oil functions as a spring as well as a shock absorber.

The compressible silicone oil is brought to a predetermined pressure in an inner cylinder. This pressure acts on the surface of a piston rod and so produces the beginning force of the spring.

The liquid silicone oil in the cylinder is initially under a predetermined pressure. Once the piston rod immerses in the cylinder ( due to an external force ) the silicone oil is compressed whithin the cylinder.

The internal pressure grows and attains its maximum when the piston rod is completely immersed. When the external force is released the stored energy pushes the piston rod back into its initial position. The element is again ready for use.

All PIT Elements consist out of the components listed below:

Inner Cylinder:

Casted or machine tooled out of a 42CrMo4V steel steel bar. FERNOX heat treated (rustproof) and hardened to 65 HRc.

Outer Cylinder:

Machine tooled out of St52 seemless steel pipe.

Piston Bearing:

Machine tooled out of 42CrMo4V steel bar.

Piston:

Machine tooled of 1.4021V stainless steel bar, inductively hardened and polished.

All seals and aditional components are supplied by International suppliers.

The overall volume (size) of a PIT Element is only 21% in comparison to a conventional steel compression spring.

By using a compressible liquid, PIT is in a position to design and manufacture much smaller spring elements, all the while keeping the same forces and stroke of a conventional element.

The drawing above shows a comparison in size between a conventional track tensioning device (including greaser) a PIT track tension