Tempering Technique  Manufacturers, Traders, Suppliers

Precise, high preload forces with constant friction due to purely torsion-free preloading with calibrated assembly tools. With the CLAMP™ expansion nut, pretensioning of bolted connections becomes considerably easier, lighter and safer. For the first time, the torque can be directly converted into a reproducible preload force. The CLAMP™ expansion nut is a mechanical pretensioning system that can be used for practically all bolting applications. Because the CLAMP™ is a nut that replaces conventional nuts, but does not turn in the bolt thread!
The design of the CLAMP™ expansion nut
The special twist lies in the design. The CLAMP has its own clamping thread and washer. This means that all relative movements are combined in the CLAMP™ expansion nut and the preload forces can be calibrated independently of the application.
 This means: No turning on the component surface and no turning in the bolt thread.

Low space requirement With an outer diameter of only 1.6 x nominal thread diameter, the CLAMP expansion nut is smaller than a hexagon nut. This offers new possibilities in design. Because the CLAMP™ can be placed directly on a wall of the housing. And because the drive of the Torc tensioner has the same radius, no larger installation space is required.


 Preload force accuracy
The clamping thread of the CLAMP expansion nut is slightly larger than the bolt thread, but has a much smaller pitch. This reduces the torque required for clamping and ensures the use of smaller and handier TorcTensioners. As a result, the bolt to be tensioned is pretensioned torsion-free and for the first time up to the yield point. The low preload force scatter of less than ±5% can only be controlled by this closed force system.


 Temperature resistant
The CLAMP expansion nut is designed for temperature ranges up to 320°C or 450°C as standard. This is where the system shows its clear advantages in terms of reusability, fast dismantling and assembly, thus ensuring a significant minimization of radiation dose in the nuclear power plant sector. For higher temperatures we recommend the torsion-free screw SmartSTUD™.

Technical features of the CLAMP™ expansion nut:

• Applicable for practically all screwing applications
• No external reaction point necessary i.e. screwing without reaction arm
• Hand-free screwing even when working overhead
• Side load free pretensioning
• Torsion-free pretensioning
• All bolts are evenly pretensioned
• High working speed
• Less equipment required for installation
• High preload force accuracy ± 5
• Low tool weight
• Transmission of exact torques up to 190,000 Nm
• Easy to operate
• Risk of accidents is significantly reduced
• Parallel clamping with several tools is possible with only one fitter
• Doubling the working speed
• Protection of the bolts
• Protection of the machine support surfaces
• No back-up keys required
• Reduced load on the tool