US 4,779,240 A · Ultrasonic sensor system

Abstract

An ultrasonic sensor system particularly for automatic door openers of a swinging door type, in addition to sensors (14) for people approaching a door for controlling opening and closing purposes, has at least three microprocessor controlled ultrasonic beam transducer (40, 41, 42) for projecting expanded unidirectional ultrasonic beams in a selected directions in a detection zone in the path of the swinging door and ultrasonic detector for converting reflected single multiple path ultrasonic beam energy into an analog electrical signal which constitute an acoustical image of objects in and bounding the selected detection zone. This acoustical image is stored or, a number characteristic thereof is stored and this acoustic image is then compared with a later acoustical image of an object in the selected detection zone and then the comparison is used to signal a lack of correlation between the first and second acoustical images to produce a signal preventing operation of the door opening. In a preferred embodiment, aspect ambiguities and problems of acoustic "transparency" are avoided by using direct multiple path reflections of three or more ultrasonic beam transducers projecting crossing beams and which have their signals multiplexed, controlled, and processed by a single computer microprocessor chip.

Claims10

Dependent claims

In an automatic door opener for swinging doors having a door operator and sensor means for detecting a person for whom the door is to be opened, for producing a door opening signal and means coupling said door opening signal to said door operator to open said swinging door, the improvement comprising,

at least three ultrasonic beams transducer means for projecting at least three ultrasonic beams at three different angular orientations, respectively in a common selected detection zone in the path of said swinging door, at least one of said directions being centrally located on the swingside of said swinging door, and means for converting reflected ultrasonic beam energy to digital electrical signals constituting a first plurality of acoustical images of objects in said common selected detection zone including acoustic images caused by intratransducer reflections,
means for storing said first plurality of acoustical images,
means for comparing each said stored acoustical image in said selected detection zone with a later and corresponding plurality of acoustical images of objects in said selected detection zone, and
means for indicating the lack of correlation between said plurality of stored acoustical images and said later plurality of acoustical images, respectively, and producing signals preventing operation of said door opening signal.

1 more element

In an automatic door opener for swing type doors having an approach side and a swing side, means on said approach side for sensing the approach of a person to the door and producing a door open control signal in response thereto, door operator means connected to said door for opening said door upon said means for producing said door open control signal, the improvement comprising,

a first, second and third ultrasonic transducer for producing first, second and third acoustic images of a detection zone on said swingside of said door including acoustic images caused by intratransducer reflections, said second ultrasonic transducer being centrally located to project an ultrasonic beam in the central area of said swingside,
means for causing said automatic door opener to go through a predetermined number of operating cycles,
means for storing said acoustic images produced during said predetermined number of operating cycles to develop a plurality of safe acoustic images for said swingside,
subsequently producing fourth, fifth and sixth acoustic images at said first, second and third ultrasonic transducer,
means for comparing the respective stored acoustic images with the acoustic images produced on subsequent automatic door openings to detect the entrance of an object in said detection zone and produce a door inhibit signal when said means for comparing detects the presence of an object in said detection zone.

2 more elements

Dependencies are inferred from the claim text.

Ultrasonic sensor system

Life of this patent

Ultrasonic sensor system

Life of this patent

Abstract

Claims10