There are a lot of types of actuators (or cylinders) and they are invaluable for moving machinery components and loads in a linear direction smoothly and efficiently. However, many applications require both forward and backward movement under power, and that requires full control in both directions. Double-acting cylinders solve this problem, producing thrust to extend the piston and then to retract it–back and forth or up and down.
A single-acting cylinder exerts force in just one direction, using another mechanism such as the counter-weight or force of the item being actuated to bring the stroke of the cylinder to its original position.
Where are Double-Acting Cylinders Used?
There are myriad applications in industrial, manufacturing, and other settings where a double-acting actuator provides a simple solution that is both robust and reliable. The task might be one that happens thousands of times a day or one that happens infrequently. But whether you’re opening and closing a gate on a conveyor line or the door to the International Space Station, the function is mission-critical for the business at hand.
Here are just some of the real-world applications that illustrate how double-acting cylinders can be used:
- Knifing – In paper-making, paper comes off giant rolls and must be cut into smaller rolls, for example. Machinery could be designed to cut, stop, and hold in position until the next cutting point arrives, but a double-acting cylinder moves at the same speed as the paper to swipe on the fly, retract and reposition for the next slice.
- Door manufacturing – Doors, windows, and cabinets have multiple panels that must be assembled, glu
ed together, and held in place to set.
This can be accomplished using multiple large clamps, but using a series of double-acting cylinders to clamp vertically along the sides and horizontally along the top and bottom provide uniform pressure and release, then deliberate, powered retraction. - Warehouse conveyors – An arm mounted to a double-acting cylinder above the conveyor can reach down, swipe an item into a box or onto another conveyor, then retract till needed again.
- Cage washer – A sprayer attached to a double cylinder can move smoothly back and forth to ensure a thorough wash cycle.
- Hot furnace – Safety is paramount in foundries where furnaces reach extreme temperatures. A double cylinder opens the door when needed but otherwise ensures the door stays closed.
- Silk-screening – This process uses a squeegee-like device to sweep ink over the fabric in one direction, then reverse itself to sweep in the opposite direction. This ensures even coverage.
- Powder-coating – Uniform coverage is crucial in painting and powder-coating. Double-acting cylinders can operate sprayer equipment both vertically and horizontally simultaneously to achieve an even coat.
You can find a double-acting actuator hard at work behind the scenes in non-industrial machinery, too, from elevators and forklifts to car transport carriers, log-splitters, and earth-moving equipment. One entertaining example we like is a funhouse or haunted house, where double-acting cylinders operate animated mannequins–out of the dark to give you a fright, back into the closet to await the next “victim.”
Configuration Options for Double-Acting Actuators
Pneumatic cylinders are usually the best choice for many applications. Pressurized air is commonly available, and pneumatic cylinders can meet tough performance standards, yet they are compact and cost-effective to purchase and maintain. Many of our W.C. Branham pneumatic actuators are configured for two-way action, including:
- MAGTEC®
- pneU-SA®
- DURATRK™ (can be modified so that the band is inverted, allowing the use of a custom arm that exerts the same force on both sides.)
- Cable cylinders
- OVLPRO™ rodded cylinders
Whatever your application, if you need to move a load in both directions, double-acting cylinders are the way to go. If you need help choosing the configuration details that will give you top performance, remember we’re always here to help.
