June, 2001

Sensors:

'Prox Actuator' Extends Inductive Sensing RangeBy Inches

Balluff has developed a solution to a problem that it says often prevents use of inexpensive inductive proximity sensors for presence detection, i.e., their limited range. Until now, the only way to increase the range of an inductive proximity sensor was to increase its size, and thus its power. However, this led to bulkier, 'fatter' sensors that cost more and could be difficult to mount in confined locations.

The Prox Actuator is designed to 'artificially yet effectively' increase the prox target detection range up to 3.8 in. and uses inexpensive, small-diameter sensors. Here's how it works: a threaded stainless steel actuator is mounted in the traditional thru-hole style, such that the extended end of its spring-loaded plunger comes in contact with the target. The other end mounts in an anodized aluminum mounting clamp along with a 4- or 8-mm proximity sensor (depending on the model).

When light contact with the target is made, the plunger is pushed back and its opposite end is detected by the prox. As the target moves away, the spring returns the plunger to its original extended position.

The system is designed to save money by requiring only a small inexpensive proximity sensor that is now isolated from damage through accidental target contact. It is said to be ideal for limited-space and hazardous-environment applications, as well as for situations where the target is not made of metal (thus undetectable by an inductiveprox).

Actuators are available in M8 and M12 sizes and withstand impact to 100 Newtons. Mounting clamps are machined for either 4- or 8-mm sensors and are available in straight or 90-deg versions for installation flexibility.

Balluff Inc.
Florence, KY Circle 110