Driven linear actuators used on tobacco cutting machine

Garbuio Dickinson is the UK arm of Garbuio SpA, a world leader in the design of tobacco processing machinery. The Garbuio Dickinson product programme includes a tobacco cutting machine range, the design of which ensures a near-vertical cutting action, with reduced push-in and pull-out forces acting on the tobacco cheese. As a result, a high quality of cut can be obtained with reduced compression of the tobacco.

The machine is fed by a vibrating tray feed that is routinely removed for cleaning. Weighing 1800kg it is a little too heavy for manual handling on castors; on the company's standard offering, therefore, the feeder is moved on air skates. Peter Todd, a Senior Design Engineer, says: "One customer, however, wanted to take things a stage further and asked if we could devise something which would actually pull the feeder accurately into the machine."

With only 5mm clearance between the feed tray and cutting machine side walls, the search was on to find a way to guarantee no contact between the two. The HepcoMotion DLS3C was available as an off-the-shelf product; it is supplied as standard with a lightweight aluminium beam that provides rigid support for cantilevered loads with the minimum of inertia.

Unlike other systems, the drive for the DLS3C linear actuator is mounted on the carriage and not connected to the end plate. This means that the motor, carriage and cables remain stationary and the beam is the moving part. For the Garbuio Dickinson application the actuator was also specified with a corrosion-resistant coating, which is another standard option.

Other factors governing Garbuio Dickinson's choice of the DLS3C was its tolerance of contamination, an obvious requirement in the presence of tobacco dust. Also the overload clutch feature on the motorised gearbox would limit the push/pull forces from a safety standpoint.

Parallel guides

The resultant tray actuator that Todd designed comprises two linear systems, linked by a common shaft to ensure it moves in and out in parallel. The moving tray is supported by a pivoting mounting to allow the connecting end of the tray to rise and fall as the feeder is lifted by its air skates. The locking pins can be retracted when required for occasions when the feeder needs to be released for maintenance. Two adjustment rollers support the tray as it slides in and out, allowing it effectively to see-saw within defined limits.

Todd concludes: "In the event, with the air skates activated, the system was not that dependant on being powered, but the design of the guidance system has proved a major factor in the success of our product."

Follow the link for more information about HepcoMotion DLS linear actuators.