Air motors provide the right stall characteristics
03 December 2007
For stop/start applications where the drive speed is low and torque high, the piston air motor is an excellent choice. Providing testimony to this is aluminium foil tray manufacturer Coppice Alupack. This Bridgend-based company are systematically replacing all its electric drives on rewind systems that handle the surplus foil after the aluminium coil has been stamped. Inclusion of Huco Dynatork air motors has not only simplified the design but also made it more controllable and safer.
Webbing or lacing is left after the foil is stamped and blown to form aluminium containers. Much of this is gravity fed out of the press. On certain tools however it needs to be rewound and its tension maintained allowing containers to be ejected cleanly and assist new foil to be fed-in efficiently.
The original system for rewinding this material had its problems. Its electric drive with limit switches and inverter for speed control made for a complicated design and the high torque involved presented a degree of risk to the operators when removing the coiled lacing. A re-design was clearly needed and the Huco Dynatork air motor offered many advantages.
“Stall characteristics were the main features we were looking for as well as compact design and ease of installation,” explained Engineering Manager, James Lamin. “As we obviously work to food standards the replacement motor needed to be robust and clean.” Trial units were readily available from Huco Dynatork to test the concept before order placement and technical back-up provided to optimise the design.
Initially Huco Dynatork piston air motors were requisitioned to replace the electric drives on the standard rewind system. Several bespoke rewind units have also been subsequently made. These are self-contained and transportable from press to press to accord with the tools being employed.
“The piston air motor has allowed us to adjust most of the tension out of the system to eliminate lacing breakage. It has also made the process inherently safer by reducing torque and negating the need for any electrical cables.” A further benefit is that maintenance of the motors can now be carried out by a shop-floor technician instead of a skilled electrician, saving cost and minimising downtime.
The Huco Dynatork motors run from 0 – 220 rpm for 24 hours a day in a cycle that goes from stall to start in the order of sixty times per minute. “They have worked very well,” James Lamin concludes. “Three units are now running on the shop floor and we have plans for more as the year progresses.”
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