Download Catalogue of telescopic cylinders

Di Natale-Bertelli has been a manufacturer of telescopic hydraulic cylinders for tipper and lifting in agricultural and industrial sectors since 1960 and, with an annual production of over 65,000 telescopic cylinders and a production area of 10,000 m², it places itself as a strategic and reliable supplier for the markets all over the world.

The first European manufacturer of telescopic cylinders to have obtained the CE certification, with reference to the regulation CEE 2006/42

We are one of the few companies worldwide that use the treatment of salt bath nitriding, called TENIFER ®, within its production process, ensuring a considerable performance at the sliding of the extensions and a greater resistance to wear and fatigue.

The exclusive use of mechanical tube without welding MW450 and E470HL at high mechanical strength supplied by two European producers Tenaris-Dalmine® and Mannesmann® allows us to get the sliding guide directly on the extension itself. This feature is still unsurpassed on the market and the quality of our product differs from that of all other manufacturers that use plastic guide for the same purpose. This process offers an additional guarantee of reliability and safety of our products, allowing the maximum extension of the cylinder right to the end of the stroke and ensuring the mechanical stop in case of breakage of the end valve stroke, when it’s used.

Thanks to special machines we roll all surfaces of the extensions providing a roughness of 0.20 micron; this process ensures a long life to the cylinder and reduces the need to replace the seals which, through the use of high quality plastic material, can work with temperatures between -40 ° and +110 ° giving the possibility to use our products in all weather conditions.

One of the most important targets of Di Natale-Bertelli is to meet customer’s requirements; this makes our company an ideal partner for anyone needing quality, reliability, technical advise and respect of delivery times.

The UNI EN ISO 9001/2000 certification guarantees continuous improvement of the quality standards and the production process, always subject to regular inspections, with particular attention to the final cylinder’s testing carried out on 100% of each cylinder with minimum pressure from 200bars to 250bars.




The telescopic cylinders are made with seamless rolled tube big thickness:

  • E470 EN10297-1 Rm=650 N/mm² Rs=470 N/mm²
  • C45 EN10083 Rm=630 N/mm² Rs=370 N/mm²
  • base and ball socket joints in pressed steel:
  • S355J2G3 UNI 10025 Rm=510 N/mm².
  • S355JR UNI 10025 Rm=510 N/mm².


The saline nitriding treatment, correctly know as the «TENIFER TF1 Degussa process», used by Di Natale – Bertelli S.p.A means that the stages can be free from bushings or guide rings as they have sliding surfaces which are highly resistant to wear and seizing, principally as a result of high surface hardness of HV-5/12=500-550.
The prime advantage of these stages is that due to the characteristics described above, they are free from the related ring and bushing seats, giving them mechanical strength at the extremities which far exceeds the standard available on the market and leaving them free from problems with burring.

This also allows a longer guide and enables the cylinder to be operated at maximum pressure at the end of its stroke.


The outer surfaces of the stages are subjected to an initial grinding phase followed by honing, giving them a degree of roughness of 0,07÷0,15 µm, tested by a surface roughness.




The specially shaped seals and scrapers are project by Di Natale – Bertelli S.p.A.:
Material : polyurethane: (Du Pont)
Maximum pressure 400 Kg/cm² (395 Bar)
Temperature from -40 to +110 C.
Maximum piston speed 0.5 m/s
Oil : Hydraulic oils and lubrificants mineral based.



All cylinders are subjected to final operational testing at hydraulic pressures of 240 Kg/cm2 (235 bar).
Cylinders from diameter 240 are tested at 205 Kg/cm2 (200 bar).


All the products are projected by international regulations CNR-UNI 10011 considerated a safety factor Ks = 1,5.