Rodless

Rodless refers to a class of linear actuators that provide axial motion without a protruding piston rod. In rodless designs, the piston moves inside a cylinder, while the load attaches to a carriage that slides along guides along the length of the actuator. The actuation force is transmitted to the carriage through a mechanism that may be mechanical (tie rods, belts, or chains passing along a slot or through end blocks) or noncontact (magnetic coupling across the cylinder wall).

Two common configurations are used. Slotted or mechanical- linkage rodless actuators rely on a groove or slot and a connection such as a belt or chain to move the carriage along the length of the cylinder. Magnetic rodless actuators use permanent magnets to couple the internal drive to an external or internal carriage without a through-wall opening, avoiding a slot altogether.

Applications for rodless actuators include situations requiring long strokes within a compact envelope, where the load must not protrude from the end surfaces or where snag hazards need to be minimized. They are used in packaging machinery, textile equipment, machine tools, and semiconductor manufacturing, among others.

Advantages include a longer stroke in a compact form, reduced external protrusions and snag risk, and flexible routing of auxiliary services. Limitations can involve higher cost and complexity, potential reductions in lateral stiffness compared with rod-type cylinders, sealing and wear considerations at interfaces, and limited suitability for aggressive side loads or highly curved paths. See also pneumatic actuator, hydraulic cylinder, and linear motion systems.