A linear-drive system can be added to an existing drive with only a simple belt-and-pulley assembly.

The Amacoil/Uhing linear-motion assembly from Amacoil Inc., Aston, Pa. (www.amacoil.com), links to the main motor via a simple pulley system without the need for additional motors and controllers.

The main drive motor need not be reversible because the system automatically reverses through purely mechanical means. The drive motor can rotate at any desired speed in one direction, and does not need to be stopped or geared down to reverse the drive head.

Besides simplifying machine design, setup, and operation, the assembly reduces operating costs for reciprocating motion because multidirectional motors, sensors, and controllers are not required. Because the system reverses without changing gear ratios or other controls, longer periods of uninterrupted production are possible.

The system also enables variable linear pitch. The drive head features a pitch-control lever users set to specific application requirements. Linear pitch may be adjusted on-the-fly without changing motor speed or other controls. Once set, linear pitch (the distance the drive head travels per one shaft revolution) remains constant, regardless of drive-motor speed.

The linear-motion assemblies run on a smooth, threadless shaft which prevents clogging and jamming. Axial thrust capacity is up to 800 lb and accuracy is ±0.005 in. Travel speed is to 13 fps over a maximum distance of 16 ft. The assemblies can be used for applying glue and adhesives, winding material onto spools, spraying, cutting, coating, packaging, and in many converting and assembly operations. Prices start at under $1,000 for basic systems.