Designer's Corner 516

Smart valve

Instead of ganging two or more conventional valves to obtain varying flow rates, consider ASCO's new Posiflow proportional solenoid valve instead. The valve is suitable for open-loop operation from 24V dc regulated or PWM power. With the addition of a plug-in control module, the package accepts standard analog or digital control signals for closed-loop, remote operation. It delivers tight control in low-flow conditions as well as temperature compensation for coil resistance. Users can define specific ramp functions for transitions between flow states, and the two-way, direct-acting valves can be easily integrated into most control designs.
Dick Stern, Automatic Switch Co. (ASCO), 50-60 Hanover Rd., Florham Park, NJ 07932, 800-972-2726.

Keyboard light

Illuminated keyboards could greatly simplify computer operations in low-light or no-light conditions. This flexible fiber-optic panel could make them practical. It consists of rows of fibers bonded to a Mylar backing, then carefully abraided to emit light along their length. The unbonded fiber tails, gathered into bundles, transmit light from a point source evenly across the panel face.

Just 0.013-inch thick, the panels can be placed between a keyboard's printed overlay and its membrane or flat-panel switches, adding just two oz. of tactile pressure to the switch assembly. Unlike other techniques, the panels produce cool, uniform light and no electromagnetic interference. In tests, the panels have endured over five million actuations without failure.
D. Joe Atchison, Poly-Optical(R) Products, Inc., 17475 Gillette Ave., Irvine, CA 92714, 714-250-8557.

Convenient cable carrier

Plastic cable carriers can travel distances of 500 ft and more. Because the upper section sags, and then glides on the lower part, a sheet metal guide trough is needed. In addition, .50 of this trough must be equipped with a glide surface to keep the car-rier at a constant height.

"Auto Glide" gets rid of the trough assembly altogether. Floating guide shoes mount to the side of the carrier, about 4 ft apart. Half again as tall as a single link, they overlap the bottom section of the carrier to guide the upper section.

While AutoGlide requires twice as much carrier as the old system, benefits are still significant. The new design saves 45% in material costs for a 60-ft run. It also eliminates several hours of assembly and labor--users simply lay out the carrier and run it right away.
Carsten Blase, igus, inc., Box 14349, East Providence, RI 02914, 401- 438-2200.