Bolt Tensioners
Function of a Bolt Tensioner (SSV) PG 3
in simplified representation

Bolt Tensioners can be removed from the bolt connection after pre-tensioning:
in comparison, Hydraulic Nuts remain on the bolt or component connection.

Basic position
Place the SSV onto the bolt to be
tensioned and screw the Thread
Sleeve down to the Piston surface.
A hydraulic high-pressure pump,
through a flexible hose, feeds oil into the space between Cylinder and Piston. The hydraulic pressure increases.

Elongation and compression
As the hydraulic pressure increases,
the resulting axial force elongates
the Bolt and compresses the
flanges. Thus, the Main nut lifts from
the flange. On reaching the desired
tension, pressurizing is stopped.

Positioning of the Main nut
The tensioning force is achieved and the Main nut can be turned down to contact the flange. When releasing the oil pressure, the desired tensioning force remains in the bolt connection. After removing the SSV, you may use the equipment for tensioning other bolts.


Special Solutions


In addition to a number of standardized Bolt Tensioners and Hydraulic Nuts, SCHAAF has already delivered thousands of customized axial Bolt Tensioners. The Design on Demand CAD system allows to realize customer solutions very
quickly. Based on axial pre-tensioning technics, a number of patented, specialized solutions have been developed during the last years. Bolt Tensioners, Hydraulic Nuts and ExpaTen, as well as the A-Loc and EcoRolls, both developed
especially for rolling mills, all represent a 100% system solution with SCHAAF’s accessories such as high-pressure hoses and high-pressure generators.

More SSV

We distinguish our Bolt Tensioners into 8 different product groups (designs) which, in principle, have all the same function.