Rotary Actuator Provides Smooth, Jerk-Free Motion

Rotary actuators have many uses in automated assembly systems. They orient parts. They operate chutes, close cardboard boxes, or route pallets on a conveyor. With the addition of a gripper, rotary actuators are commonly used in pick-and-place mechanisms. The gripper removes a part from a nest on an indexing dial, the actuator rotates 90 or 180 degrees, and the gripper deposits the part in a bin or another nest.

Or, consider a situation where a manufacturer needs a robot to quickly move parts in and out of a machine. By integrating a rotary actuator with two grippers, the robot can alternately insert unfinished parts and remove finished parts from the machine, or simultaneously grab, reorient and present two parts for further processing without having to let go of them.

In that scenario, using a rotary actuator allows a robot to complete its task more quickly by placing and retrieving two parts in one trip. This shortens overall cycle time and prevents machines from being idle.

As their name implies, rotary actuators move a load along a circular path that lies in a horizontal, vertical or angled plane. Traditionally, rotary actuators have been pneumatic devices. But, that’s changing. Electric rotary actuators provide smoother motion than pneumatic ones. They’re also more flexible and energy efficient.

One of the newest electric rotary actuators is the Elecylinder from IAI America Inc. The Elecylinder allows acceleration, velocity and deceleration to be set using numeric values. This enables engineers to adjust the motion of the actuator for smooth stopping without impact.

The actuator is easily programmed with a wireless controller. No cable connection is required. The controller can be operated from a remote location, and it be connected to as many as 16 axes. The wireless controller can be used for basic programming (positions, acceleration, speed and deceleration); reading the current position; performing a test run; jogging the motion of the actuator; releasing the brake; turning the device on and off; displaying cycle time and error messages; and resetting the alarm.

The actuator comes in four sizes. All four provide 330 degrees of rotary motion.

The smallest, Model EC-RTB4, is 45 millimeters wide and 120 millimeters long. By mounting the built-in motor vertically, its footprint has been reduced. A hollow shaft, 12 millimeters in diameter, provides easy routing for wiring and piping. The actuator’s rotation center is located in the center of the main unit for well-balanced mounting. It provides a maximum torque of 0.6 newton-meter.

Model EC-RTC9 is 90 millimeters wide and 133 millimeters long. It provides a maximum torque of 1.5 newton-meters. Model EC-RTC12 is 117 millimeters wide and 166 millimeters long. It provides a maximum torque of 8 newton-meters. Model EC-RTC19 is 185 millimeters wide and 213 millimeters long. It provides a maximum torque of 25.2 newton-meters.

Model EC-RTC12 offers an energy-saving mode. When enabled, it will reduce the device’s power consumption by up to 40 percent. However, this will also reduce the unit’s maximum speed, acceleration, deceleration and payload.

For more information on linear and rotary actuators, Cartesian robots, grippers and other automation components, click www.intelligentactuator.com or visit the company’s booth at The ASSEMBLY Show. IAI is of many suppliers of motion control technology that will be exhibiting at the show, which will take place Oct. 22-24 at the Donald E. Stephens Convention Center in Rosemont, IL. Besides motion control products, you’ll find 250 suppliers of robots, automation, adhesives, dispensing technology, parts feeders, fastening tools, software and other assembly technologies. For more information, visit www.theassemblyshow.com.