• home
• about us
• contacts
• products
  • Axial bolting
  • Torque bolting
  • Pressure generators
  • Accessories
  • Special screws
  • Training
  • Special purpose hydraulics
  • Measurements & Documentation
• services
• news
• imprint

[ Functional Principle ] [ Bolt Tensioning Devices ] [ Hydraulic Nuts ] [ Performance Variations ]

Functional principle of axial Pre-tensioning

Operation principle of pure axial torsion-free producing of force is possible with the tool "Bolt tensioning device" or the machine element "Hydraulic nut".
The bolt tensioning device as tool is mainly used to tension several of same bolt connections safe and rational.
The hydraulic nut as machine element is installed remaining onto the machine and mainly used were very quick mounting and dismounting times are required.

If the force calculated within design of the connection with axial bolt tensioning technique, first of all the holding nut and then the device are placed onto the ends of the threaded parts to be pretensioned (fig. 1). After connection to the pressure generator, the calculated pretensioning force is applied independently of the length by means of hydraulic pressure. The amount of force desired can be determined with precision by the piston area of the device and the pressure (fig. 2).

The pressure can be read off directly from a measuring instrument. When the required pressure is reached, the locking nut is to turn tight (fig. 3). The holding nut is done up until it touches the contacting surface. The device can now be removed and applied to the next bolt.

1.tension nut 2.piston 3.cylinder 4.bridge 5.main nut 6.adjusting rod 7.connector 8.sealing set 9.hexagonal nut

fig. 1: Basic setup	fig. 2: pressurisation	fig. 3: Finishing

.. have a look at this small animation:

It is also possible to download a 3D-animation here!

• as a WMV-Datei, 1.117.880 Byte
• as a MPG-Datei, 10.926.084 Byte