Photoelectric sensor assembly having compressible and sealing members

Abstract

An improved photoelectric sensor assembly has a one-piece threaded barrel housing, preferably with focus lenses formed therein. An aperture piece fits within the barrel housing, and a printed circuit board carrying the scanner electronics fits in behind it with the optoelectronic elements aligned with the aperture piece and the lenses. A power and signal cable from the circuit board extends out the back end of the sensor housing. A foam compression ring fits against the PC board and is backed by a washer, second compression ring and second washer, all of which have apertures for the cable to pass through. An end cap threads onto the rear of the threaded barrel and compresses the washers and compression rings. The foam ring gently holds the circuit board and aperture piece in place, and the second compression ring, which is preferably formed of a stiffer closed-cell material, is resiliently compressed against the inside of the entire barrel housing and long the cable to provide a reliable shock- and thermal-resistant moistureproof seal, eliminating the need for epoxy potting and close tolerance internal seals to protect the optical components from the epoxy. The end cap is preferably formed with a spherical outer surface, which may be received in a mounting bracket having a spherically sectioned aperture to permit two degrees of freedom in aligning the sensor for use in applications.