Screwdown Gears are British Company's Largest



Screwdown Gears from Renold

Renold Gears has manufactured the heaviest pair of wormwheel gearboxes in the company's history from its site in Milnrow, near Rochdale.  With a combined weight approaching 25 tons, these huge gearboxes are destined for a steel mill on the other side of the world.

Designed and manufactured to be installed in an existing steel mill in Asia, the gear units are to be fitted as the main drives of a screw down mechanism which is used to reform recently cast steel billets into thinner width sections.  The screw down gear units, driven by massive 220kW motors, literally squeeze the steel into the required section widths.

The units are a single reduction worm gear design with a reduction ratio of 21.5/1 and designed specifically for the application with a huge tooth thickness to withstand in excess of 530,000Nm of static torque.  They are manufactured in pairs and are identical externally but internally the gears are cut with opposite angle gearing  known as left and right hand threads.  This gives the desired effect of giving opposite direction of rotation of the output when both units' inputs are driven in the same direction.

Renold Gears have manufactured and supplied many similar screw down gear drives in the past and also supplied the specialised worm gears to customers who have built them into their own gearboxes.

Stephen Whitehead, Sales Director of precision gears commented; "Where sudden and huge shock loads are going to be encountered, only worm wheel sets manufactured with the maximum tooth width are suitable.  Only the combination of hardened steel wormshafts  and 'soft' phosphor bronze wheels allow these loads to be withstood with no detrimental effect on service life".

Robert Townsend, Renold Gears' Managing Director, concluded; " Our capability to undertake complete custom made systems designed to meet customer specifications, has enabled Renold Gears to continue to win these type of contracts in diverse markets around the world".

These screw downs are just two of many custom made systems and gears that have been supplied this year.