Proximity switch having adjustable sensitivity

Abstract

A magnetically operated reed switch device for use in physical security monitoring systems, machinery control systems, and the like, having a biasing permanent magnet associated therewith for providing adjustable sensitivity to the proximity of an actuating permanent magnet. The reed switch is enclosed in a cylindrical glass capsule and the biasing magnet is mounted near the capsule, with its axis of magnetic polarity parallel to an elongate reed of the reed switch, in a position adjustable along the longitudinal axis of the reed by an adjustment screw for controlling the sensitivity of the reed switch. The biasing magnet may be mounted on a screw-driven carriage or on the end of a screw moving within a tube parallel to the reed. The device is actuated by increased magnetic flux density provided by the actuating magnet, which is attached to the movable object whose position is being monitored. The switch device and its actuating magnet are fixed in protective housings having mounting means.

Dependencies are inferred from the claim text.