Machine Design

Rotary Vane Actuators Handle the Loads While Delivering the Torque

Procedures for calculating shoulder-fillet stresses should take multiaxial stresses into account, even if loading is uniaxial.

The pneumatic VRX rotary-vane actuators from Tolomatic Inc., Hamel, Minn. (, can generate up to 484 lb-in. (54.7 N-m) of torque at 100 psi and withstand axial loads as high as 23 lb (102 N) and radial loads up to 59 lb (262 N). This makes them well suited for material handling, cutting, and clamping, as well as other operations requiring rotary motion. The units come in three bore sizes: 1.0, 1.75, and 2.5 in. Each can be equipped with one or two vanes. Single-vaned models rotate 280° and generate up to 242 lb-in. of torque, while the double-vaned version rotates 100° and produces the full 484 lb-in. And larger-bore models can have an infinitely adjustable stop that lets users dial in rotational stops of less than the full rotation.

Seals are made of highly saturated nitrile, giving them three to five times the service life of Buna-N seals. The seals are also molded directly on the oversized vanes and rotor shaft for a tight fit.

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