Tuesday, 16 June 2015

Innovator Talks at UDT 2015, Rotterdam

Solution to Bolting Challenges

Bolting is a very much underestimated way of connecting parts. It needs to be well done, and
sometimes it is nearly impossible to do it in a standard way. Belgian manufacturer Safe Tensioning System (STS), with over 20 years experience in solutions for the maintenance of technical equipment, helps naval customers solve bolting challenges. The system STS commonly recommends is a Mechanical Tensioner. It enables the user to simply tighten nuts or bolts with small hand tools instead of big wrenches or hydraulics. The principle is simple: The tool uses small jack screws that are screwed into the main body and press against a hardened washer below. It provides pure linear tension without torsion in the main stud - no galling can occur as the superbolt remains static on the stud. The tensioners require the same amount of space as normal nuts, are very accurate, hold preload perfectly with vibration, and can be custom-designed to suit the user's specifications. STS said: "The applications are limitless." The tensioners have been used in submarines for a variety of purposes: hull-valves; mast to frame connections; propulsion shafts; vibration dampers; and propeller connections, according to Martin Quist, STS's Project & Sales Manager.

The tensioners are very useful in shipbuilding and industrial applications.
(Photo: Stefan Nitschke)

STS developed a new concept - expansion bolts. They are designed to replace standard fitted bolts or hydraulic bolts, which are used to transmit shear forces in positive connections. Typical applications involve couplings.
Again, this type of expansion bolt has a very simple design: a conical stud is pulled into a conical sleeve by the right tensioner, thus expanding the conical sleeve radially, the spacer positions the conical sleeve in the centre of the contact plane. The left tensioner is used to clamp the coupling halves together. Due to the split in the sleeve, a bigger radial expansion can be obtained. It compensates for radial backlash and applies a true preload inside the bore where it is fitted. Drill tolerances are allowed, no more reaming of the bores is required. Furthermore, only a simple torque wrench is required.
Source: Safe Tensioning System

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