Precision Ring Drives from the Nexen Group Inc, Vadnais Heights, Minn., combine a rolling pinion with a precision-grade bearing and gearhead. There are four drives in the series with ratios ranging from 64:1 to 220:1. Peak torque goes from 563 to 1,936 Nm. And accuracy ranges from ±11 to ±35 arc-sec, with repeatabilities of ±4.2 to ±1.2 arc sec. The drives can handle peak-torque inputs at any time, which lets it index at twice the speed of traditional camdriven systems.
The rolling pinion is 99% efficient, while the gearbox is 96% efficient, making the rotary device an energy saver. And the bearing-supported pinion rollers move smoothly across the face of each tooth, so it generates less noise and vibration than conventional rotary devices.
The drive mounts on a table supported by cross-roller bearings rated for 1,575-kN loads.