Linear-motion devices that operate with vertical loads, uneven loads, or offset forces often get their ball retainers misaligned, which can reduce overall travel, increase the force needed to move the slide, or cause the entire assembly to fail. To prevent this, engineers at Del-Tron, Bethel, Conn. (www.deltron.com), have designed an anticreep cage molded of engineering plastic and slotted in the center. Dowel pins in the base and carriage limit travel and keep the cage centered.
The slide places the bearings in a straight line, which offers the lowest coefficient of friction because the rolling elements are separated from each and not required to turn corners. The bearings run equal distances on a pair of tracks, letting them run with little friction, wear, or skidding. The straight-line design also lets users adjust preload. A steel gib uniformly loads all rolling elements in the bearing and reduces looseness and play.
Anticreep slides are available with travel ranging from 0.5 to 5.0 in., capacity ranging from 1.5 to 18 lb, and lengths from 0.75 to 6.06 in. Accuracy is 0.005 in./in. of runout.