A weakness of conveyor systems operating in grimy and aggressive environments can be the need to constantly lubricate and protect the actuators used for high repetition tasks.
Key areas of concern include actuators for lift gates, drive tables, transfer sections, belt tensioners, belt centre guides, waste scrapers and friction brakes – all areas that can be exposed to grime, debris and waste, and can disrupt the seals and shafts of conventional pneumatic and hydraulic cylinders.
“Because conveyor breakdowns can compromise safety and cost production, process engineers are forever on the lookout for ways to make conveyor actuation simpler and more reliable,” says Simon Agar, sales manager for national actuation and isolation specialist, Air Springs Supply.
“Working on the reasoning that fewer moving parts are better, one excellent solution for simplicity and reliability can be to employ Airstroke actuators, which have no seals, shafts or internal moving parts,” says Mr Agar, who has more than 15 years’ experience in engineering actuation solutions using the Firestone Airstroke range of actuators from Air Springs Supply.
These enormously tough rubber and fabric actuators are, in effect, balloons or bellows engineered to particular shapes for particular tasks. They are rapidly inflated and deflated, to provide the actuation and retraction required by modern high-speed conveyors employed in heavyweight industries.
Supplying actuation forces, from a few dozen kilograms up to 40,000kg a unit, Airstroke’s single, double and triple-convoluted and rolling sleeve designs are made exactly the same way as the air springs used as suspension springs in heavy vehicles, such as semi-trailers. The compact, but powerful, actuators are every bit as tough as the Airmount isolators found under giant semi-trailers, hauling heavy grimy loads day after day, year after year, says Mr Agar.
Air Springs Supply is expanding the Airstroke range – from the largest (one metre diameter) models down to palm-sized Airomatic mini actuators for delicate jobs requiring a clean actuator that does not need lubrication and can cope effortlessly with high-repetition tasks. Eliminating lubrication eliminates another sticky surface for waste adherence.
“One of the beauties of this form of actuation is the inherent flexibility of the actuators when they meet their working surface,” says Mr Agar. “Being made of rubber and not having any rods or seals to damage, they allow maintenance-free deflection on a continuous basis. Their flexibility also makes them ideal for applications, such as belt take-ups or roller friction applications, where they may be applied against an oscillating surface,” says Mr Agar.
“They can also stroke through a radius without a clevis, thus eliminating both complexity and cost when you need to actuate through an angle. Their ability to soak up shock without damage, while delivering high-repetition strokes means they are highly applicable to conveyor transfer, gate and lift sections.”
Air Springs Supply’s growing Airstroke range offers actuation strokes, ranging from 12.5mm for the tiny (16mm high deflated) Airomatics through to more than 300mm for triple-convoluted models that are used as both actuators and isolators in heavy industry.
“We don’t say Airstrokes are the ideal solution for all actuation needs – every professional knows that each case needs to be considered on its own special needs. But we do know, from a generation of experience, that they can save a lot of time and money over a vast range of applications because we have installations that have completed millions upon millions of cycles with outstanding reliability,” says Mr Agar. “If safety, reliability, flexibility and repetition are engineering issues, then they can be extremely viable and economic alternatives.”
Source: Air Springs Supply