State-of-the-art rollers must meet the following requisites:
- comply with ISO standards;
- use high quality material and bearings;
- possess effective protection of bearings against external agents.
The precision steel tube is of the HF electrowelded type, seamed and calibrated externally, and produced in accordance with the UNI 7947 standard.It is obtained from a hot rolled strip with a high quality standard and a natural or pickled surface.The steels are of Fe 360-UNI EN 10025-92 quality and, on request, Fe 490 or other quality including those resistant to atmospheric and industrial corrosion (austenitic stainless steels).All tubes used by TECNORULLI have:
- reduced tolerances on the outer diameter and thickness;
- good rotundity;
- high level of straightness.
BEARING MOUNTING HEAD
They are obtained by steel sheet pressing; the forms for housing bearings are calibrated to ISO M7 tolerance.In CLAMPED STEEL ROLLERS, the heads are pressure-fixed to the tube; in MONOBLOC STEEL ROLLERS by continuous electro-welding.The latter have an exceptionally robust and resistant structure.
The shaft is made of Fe 360 quality round drawn steel and, on request, of austenitic stainless steel (AISI 304, AISI 316, etc.).It is obtained from a hot-rolled strip, normalised and calibrated in accordance with the UNI 10233-93 standard.The standard shape of connections is given on the page for each series of base rollers.
In the CLAMPED STEEL ROLLERS series and the MONOBLOC STEEL ROLLERS series for light and medium-heavy loads, the bearings are made of radial or angular ball type steel, with or without containment cage (with full complement).In the CLAMPED STEEL ROLLERS series and the MONOBLOC STEEL ROLLERS series for medium-heavy and heavy loads, the bearings are type 62 deep groove ball bearings, produced in accordance with the ISO and DIN 625 standards, from the best brands in the world.
They are made using reinforced and impact-modified polyamide resin.Depending on the roller series, they consist of a double or triple labyrinth, with double-lip internal seals, and protective shields made of super-tough polyamide resin reinforced with glass microspheres.The right grease reservoir guarantees lifetime lubrication of the bearings and protection systems.
RUNNING IN AND QUALITY CONTROL
On completed assembly, the roller is rotated in order to obtain uniform distribution of grease for both bearings and labyrinths.The final test calls for dimensional control of the roller, its smoothness and its silence