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.
Key areas on which they focus include actuators for lift gates, drive tables, transfer sections, belt tensioners, belt centering guides, waste scrapers and friction brakes.
All these areas can be exposed to grime, debris and waste that can disrupt the seals and shafts of convention pneumatic and hydraulic cylinders, says pneumatics engineer, Chris Webb.
“Working on the reasoning that fewer moving parts are better, one excellent solution for simplicity and reliability can be to employ actuators without seals, shafts or internal moving parts,” said Webb, who has more than 25 years experience engineering actuation solutions using the Firestone Airstroke range of actuators.
The tough rubber and fabric actuators are in effect balloons or bellows engineered to particular shapes for particular tasks. The single, double and triple-convoluted and rolling sleeve designs are made the same way as the air springs used as suspension springs in heavy vehicles such as semi-trailers.
The range available throughout Australia is currently being expanded from the largest, 40,000kg capacity, models down to palm-sized Airomatic mini actuators for delicate jobs requiring a clean actuator that doesn’t need lubrication and can cope effortlessly with high-repetition tasks. Eliminating lubrication eliminates another sticky surface for waste adherence.
“And another of the beauties of this form of actuation is the inherent flexibility of the actuators when they meet their working surface. Being made of rubber and not having any rods or seals to damage, they can bend or flex to the surface of the belt or conveyor section. Their flexibility also makes them ideal for applications such as belt takeups or roller friction applications, where they may be applied against an oscillating surface.
“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 in applications ranging from food and beverage processing and packaging to minerals processing,” Webb said.
The Airstroke range offers actuation strokes ranging from 12.5mm for the tiny (16mm high deflated) new Airomatics, through to more than 300mm for triple-convoluted models used as both actuators and isolators in heavy industry. Current Australian uses, for example, ranging from lifting for splitting of giant mining shovels for maintenance, through to counter-pressure devices on hydraulic stamping presses of more than 100t capacity.
“We don’t say for a moment that Airstrokes are the ideal solution for all actuation needs, because every professional knows that each case needs to be considered on its own needs. But we do know they can save a lot of time and money over a vast range of applications, because we have installations that have completed millions of cycles with outstanding reliability,” said Webb.
Air Springs Supply 02 9807 4077.