For many bulk conveying applications, the sorters, diverters and pull-offs that route products to their next destination must be trim to use up as little valuable floor space as possible. Engineers at Hytrol Conveyor Co., a producer of conveyor systems, needed such space-saving components when designing a diverter for an overhead pull-off system that would divert 150 lb boxes to a different conveyor line. For help, they turned to Tolomatic of Hamel, Minn., manufacturers of rodless-style actuators.
The traditional actuator used to operate diverters on a conveyor system is a pneumatic rod cylinder. Normally, a rod cylinder with up to a 48-in. stroke would be mounted off to the side, perpendicular to the conveyor, and operate a paddle that pushes a product off the conveyor or diverts it to a different line. However, these rod-style diverters consume a lot of space because the cylinder extends about 48 in. beyond the width of the conveyor. Hytrol offers a framed overhead diverter design that uses a Tolomatic BC2 rodless pneumatic actuator. The BC2 actuator’s length is the same as the conveyor’s width, and the carriage moves entirely within the length of the actuator.
The BC2 rodless pneumatic actuator’s length is the same as the conveyor’s width, so the carriage moves entirely within the length of the actuator saving space in conveyor assemblies.
“The BC2 actuator is a space saver,” said Guy Holloway, president of Fraleigh Company, the local distributor for Tolomatic that helped design the application for Hytrol. “It can be mounted over or under the conveyor, depending on the application.”
A rodless band cylinder actuator contains its stroke within the length of the cylinder itself. For example, a 2-in. bore cylinder with a 48-in. stroke can save up to 43% of space compared to an equivalently sized rod cylinder. In addition, a rodless actuator guides and supports the load throughout the entire stroke length, so there is minimal bearing wear and load deflection. Thus, bending moments are better controlled for longer wear without seal or bearing stress.
According to Holloway, Hytrol initially looked at other types of actuators, but liked the size and performance of the rodless actuator and found it easy to mount within its pull-off design. With fewer carriage bolts and an adaptive mounting system, the rodless actuator saved assembly time and labor.
“In Hytrol’s overhead diverter design, the actuator has to move a large triangular paddle that pushes boxes weighing up to 150 lb,” said Holloway. “This can create very high bending moments on the actuator’s carriage and guide bearings. The BC2’s carriage has a robust bearing system with high side-load capacity. When designing for high bending moments, sometimes we specify dual carriages on the actuators to distribute the forces.”
Depending on the application, Hytrol uses BC2 actuators with 1.5, 2.0 or 2.5-in. bores. The 2.5-in. BC2 actuator can exert forces of up to 800 lb (362.8 kg) and withstand bending moments of up to 1,800 lb (203.7 Nm), depending on carrier selection.
Filed Under: Factory automation, Conveyors, Linear motion • slides, Motion control • motor controls