Monthly Archives: August 2009

Telebelt Low Clearance Applications

How Do I Replace My Telescope Cable?

The telescope cable on the main belt won’t last forever. Two to three years is about it, depending on your cleanliness, maintenance and location (winter chemicals can speed the aging process). Equalizer cables last much longer and do not require the tension a main cable needs to effectively do its job.

Cables are fairly easy to replace, unless they have broken. For complete instructions on the TB 105 and TB 130 telescope cable, download the Summer 2003 PDF, Tips on Replacing the Telescopic Drive Cable (PMA-0010-6 TB). Use ONLY Putzmeister authorized cables. Some types of cable (i.e., non-rotating) are unsuitable.

When replacing the main cable, inspect all sheaves. The eight-inch (203mm) sheaves mounted horizontally will wear out on their lower edge first, so check your Operator’s Manual as some can be turned over before replacement is necessary. If the effective diameter has been reduced, cables will contact end frames. Best practices indicate having two sets of eight-inch (203mm) sheaves and bearings, as well as one set of 10-inch (254mm) sheaves and bearings, available when replacing cables, just in case.

TB 105, TB 110, TB 130, TB 600

Visually inspect cables as part of your daily operational routine. First, fully extend the boom. Then, lock out the machine and walk along under the cables.

Lubricate the cables with a penetrating chain and cable lube. The cable has a wire rope core, and penetration is critical. DO NOT use any products with graphite, as it softens plastic slides on the boom.

• Assess the wraps on the telescope drive with care. Also check the cable running from the anchor point (Dead Head) of the telescope drive, out to the tip section end frame and back to the drive sheaves.

Maintain telescope cables at 2,500 psi (172 bar) with the tensioning jacks. If you are between holes at 2,500 psi (172 bar), go to the next higher hole.

Watch for signs of a loose main cable during operation. This could mean that there is too much sag in a fully extended cable, or drive sheaves spinning in the cable wraps. Spinning drives create heat, which shortens the life of the cables.

Replace the cable as soon as possible if ANY broken strands are observed. Cable failure occurs shortly after broken strands are observed.