With more than 30 years experience in conveyor design and production, LAC Conveyor Systems of Bulwell, Nottingham Lane chose Lenze aluminium worm geared motors for their range of pallet roller conveyors.  LAC sell mainly to UK machine building customers, often in the food and packaging industries.  Their modular design of pallet roller conveyors are often to be found end-of-line, perhaps after a palletiser.  The choice of Lenze aluminium worm geared motors was based on the need for rapid response to market demands, and for a cost effective drive that is adaptable and simple to mount.

Pallet conveyors can be either stand-alone units with stop/start functionality, or form a fully automated zero pressure accumulation system.  They are designed for the heavy end of the market with pallets or drums fed onto the conveyor by machine or fork truck.  LAC design for heavy duty use with thick walled rollers driven by chain, a fully enclosed side frame of 5mm folded steel and an external shaft mounted motor.  Normally loads are up to 1500kg, but LAC design for 2500kg, part of their philosophy that keeps downtime to a minimum even when conveyors get rough treatment.

Loads are driven at typical speeds from 4 to 14m/min and this relates to gearbox output speeds 16 to 56r/min, a range where worm gears are well suited and economical.  The Lenze aluminium worm range covers power from 60W to 2.2kW with output speeds 10 to 260r/min, many models available from stock.  Geared motors are bolted to the side frame of the conveyor using a standard gearbox flange.  The roller shaft passes through directly into the gearbox hollow shaft.  This optimised mounting means that the gearbox replaces one bearing and takes half the load from the roller.  Motors have a wide voltage range, a thermal switch and metal cowls as standard.  The gearboxes are grease lubricated for a maintenance free 15000 hour life.

LAC find that their customers demand ever-shorter lead times.  Instead of a standard delivery of 6 weeks, customers and in particular the food industry, often look for times of two weeks or less.  Furthermore food industry customers may need frame construction in 304 or 316 stainless steel with modifications to remove dirt traps.  This puts heavy pressure on the Design Engineers and component suppliers such as Lenze.  However the end customer gets one further and major advantage – LAC have a sufficiently large manufacturing facility to completely build and test the conveyor on site before it is shipped.

In a recent contract, LAC provided a roller pallet conveyor for a sterilisation plant.  Medical equipment was loaded onto steel jigs on the conveyor by a 6-axis robot.  The robust construction of the conveyor minimised the deflections which was essential factor for the positioning accuracy of the loading and un-loading robots.  The loads then travelled around a rectangle with chain transfer units for the 90° corners, stopping at the sterilisation cabinet.  A reject spur was added to allow isolation of faulty loads without stopping production.

The sterilisation plant was one case where Lenze inverters were needed, to accurately position the jigs for robots to load and unload. The inverters slow the load to a stop at a fixed profile which greatly improves the accuracy of the stop position compared to an uncontrolled stop.  Although many conveyors run at fixed speed without inverters, sometimes the final speed required is uncertain.  Also certain types of loads can be unstable and liable to toppling, and here the inverter effectively acts as a soft start/stop.  The Lenze SMV inverter with IP65 enclosure is a good choice as it can be bolted without a panel directly to the machine frame.  Food industry customers generally prefer a stainless steel enclosure, and here the simple and low cost IP20 smd inverter is suitable for enclosed mounting.

Chris Unwin, Sales Manager of LAC Conveyor Systems comments “Being a privately owned company, we are able to design and manufacture in-house almost all types of conveyors systems.  The choice of geared motor is an important element of our customer service.  Lenze worm geared motors are a good fit combining availability with economy”.

LAC Conveyor Systems have been designing, developing and building both standard and bespoke conveyors since 1981 including chain, plastic, food industry, roller and spiral designs.  Contact tel: 0115 975 3300, www.lacconveyors.co.uk