Aspooling device from Amacoil Inc., Aston, Pa. (www.amacoil.com), places the take-up spool in line with the motor and drive. This keeps the entire package compact and provides mounting flexibility. A guide attached to the traversing rollingring drive moves back and forth to ensure even placement of material on the spool. The drive travels on a smooth, case-hardened (RC 60) shaft.

The rolling-ring drive from Uhing Co., Germany, uses angled bearings with a ridge machined on the inner race surfaces to convert the rotary motion of a threadless turning shaft inserted through the bearings into precise linear motion. Travel speed is a function of bearing angle and shaft rotation speed, while travel direction relies on bearing angle in relation to the shaft and direction of rotation. In the spooler, the shaft always turns the same way, and a linkage changes the bearing angle to alter travel direction.

The drive lets engineers control direction and travel speed mechanically, eliminating the need for programmable electronics, clutches, cams, gears, and reversible, variable-speed motors. Instead, a mechanical linkage reverses direction when the device hits an endstop, regardless of what direction the shaft is turning. Optional modifications to the linkage, made using simple hardware fixtures, lets users control drive-head movement. For example, acceleration and deceleration, as well as dwell time can be tailored to specific applications. It's also possible to change travel speed on the fly by turning a control that alters the drive's bearing angle. The threadless shaft will not collect oil, grease, and debris and does not need protective bellows or lip seals.