John P Dorr

US Patent:

47792400, Oct 18, 1988

Filed:

Apr 2, 1986

Appl. No.:

6/849079

Inventors:

John A. Dorr - Crofton MD

Assignee:

Xecutek Corporation - Annapolis MD

International Classification:

G01S 1593
H04R 134

US Classification:

367 96

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.

US Patent:

54425956, Aug 15, 1995

Filed:

Apr 22, 1994

Appl. No.:

8/231550

Inventors:

John A. Dorr - Crofton MD

Assignee:

Xecutek Corporation - Annapolis MD

International Classification:

H04R 1900

US Classification:

367181

Abstract:

A capacitance-type ultrasonic transducer is disclosed in which a thin insulating plastic film or membrane is coated on one side with a thin film conductor, such as gold, and the back or counter electrode is comprised of a gas permeable conductor material such as sintered bronze. Springs are utilized to apply pressure to maintain good electrical contact between the gold film side of the membrane and an annular conductor. Signals are applied to and taken off of the gas permeable conductor backplate. Due to the porous structure of the back electrode and the gas permeability thereof, variations in ambient presure on the membrane or film are equalized. Ranges of operating freqeuncy can be established by size of particles used to form the sintered electrode.

US Patent:

47727640, Sep 20, 1988

Filed:

Dec 1, 1983

Appl. No.:

6/556804

Inventors:

John A. Dorr - Crofton MD

Assignee:

Xecutek Corporation - Annapolis MD

International Classification:

G08C 2100

US Classification:

178 18

Abstract:

A sound wave position digitizer has a pair of sound wave beam transducers, each spaced a predetermined distance from the edges of a data surface such that the beams intersect on the data surface at substantially orthogonal angles. The beams are folded by reflectors to achieve compactness and, to further improve the form factor, the beams are coupled to the folding reflectors by acoustic horns which intersect and have a common section.

US Patent:

49146416, Apr 3, 1990

Filed:

Nov 10, 1988

Appl. No.:

7/269613

Inventors:

John A. Dorr - Crofton MD

Assignee:

Xecutek Corporation - MD

International Classification:

G01S 1500

US Classification:

367 99

Abstract:

An ultrasonic measuring transducer system in which an ultrasonic transducer transmits an ultrasonic pressure wave and receives a return echo from a target and an electronic circuitry means converts the received pulses to arrange information to a target. The ultrasonic transducer is mounted in a wall of a plenum chamber. Air flow passages or apertures surround the ultrasonic transducer and air from a supply under pressure is connected to said plenum chamber. A temperature (or velocity of sound) measuring device is mounted in the plenum chamber for measuring the temperature from which the speed of sound in the medium is determined, and a measuring chamber forming tube surrounding the transducer and air outlet apertures provide a space in which air flow is maintained at a relatively constant rate and the temperature in substantially all of the measuring path and space between the target and said ultrasonic transducer is essentially the same as in the plenum chamber. The air apertures or passages are such that the pressure drop of air between said plenum chamber and the space in front of said transducer does not affect operation of the ultrasonic transducer. The measuring chamber forming tube is a cowl having a length which is less than the ring-down distance for said transducer at its operating frequency.

US Patent:

52770702, Jan 11, 1994

Filed:

Aug 1, 1991

Appl. No.:

7/739028

Inventors:

John A. Dorr - Crofton MD

Assignee:

Xecutek Corporation - Annapolis MD

International Classification:

G01H 500

US Classification:

7386128

Abstract:

A transit time gas flow meter comprising a pair of transducers mounted at an oblique angle to gas flow in a duct for measuring the transit time of an ultrasonic pulse in both directions between the transducers and computer determines the difference between transit times as a measure of the velocity of a gas stream flowing in the duct. Each transducer is carried in a mounting assembly which is comprised of a U-shaped frame member having a base and leg members and an ultrasonic reflection surface formed on the base of U-shaped frame member. A transducer is mounted between said legs and at a predetermined oblique angle to said reflection surface. A reference target carried on the U-shaped frame member is positioned at the edge of said gas and the ultrasonic transit time to each said reference target is subtracted by the computer means from the transit times from each of transducer to the other transducer, respectively, to zero flow calibrate transit time flow meter and to improve the accuracy measurements.

US Patent:

39493482, Apr 6, 1976

Filed:

Oct 15, 1970

Appl. No.:

5/080988

Inventors:

John A. Dorr - Crofton MD

Assignee:

Westinghouse Electric Corporation - Pittsburgh PA

International Classification:

H04B 1300

US Classification:

340 8R

Abstract:

A side looking sonar transducer which has sound absorbing material extending forwardly of the active surface of the transducer elements to diminish the acoustic response over a predetermined zone for reducing the effect of erroneous reflection signals.

US Patent:

45300771, Jul 16, 1985

Filed:

May 19, 1983

Appl. No.:

6/496158

Inventors:

John A. Dorr - Crofton MD

Assignee:

Xecutek Corporation - Crofton MD

International Classification:

B06B 304

US Classification:

367140

Abstract:

A low cost, efficient, ultrasonic transducer and method comprises a narrow beam electrostatic transducer and a beam transformer operated in air for expanding the emitted beam of the electrostatic transducer relative to a single axis. The beam transformer is a sonic reflecting surface spaced from the ultrasonic beam generator and within the near field thereof and having a geometric surface in which all points of said surface are generated by the revolution of a line about a fixed axis which is normal to the plane of the electrostatic transducer. A partial surface of a cone, the axis preferably being offset from the axis of the narrow beam electrostatic transducer and placed in the near field thereof transform the narrow beam to a broad beam with the beam transformer being an effective coupling element for the emitted beam and the return echo for ranging systems which are both efficient and easy to produce and do not have significant alignment problems. Acoustic energy absorbing material can be used to bound the perimeter of the reflecting surface to better define and control the beam in cross section. The invention is particularly useful for ranging, guidance, and surveillance systems wherein an ultrasonic beam, narrow in one direction of propagation, is projected in air over a surface to detect range to an object, presence or absence of an object and its location and entrance of an object to a specified area under surveillance.

US Patent:

49441868, Jul 31, 1990

Filed:

Nov 29, 1988

Appl. No.:

7/277604

Inventors:

John A. Dorr - Crofton MD

Assignee:

Xecutek Corporation - Annapolis MD

International Classification:

G01N 2900

US Classification:

73597

Abstract:

Hot target ultrasonic measurement system in which an ultrasonic transducer for transmitting ultrasonic energy along a measuring path toward the hot steel ingot target receives a reflection echo of ultrasonic energy from the hot target along the measuring path, and electronic circuit for determining the range to the hot target from the time of transmission of said ultrasonic energy to the receipt of reflection of ultrasonic energy from said target. The temperature or speed of sound in the media in the measuring path is measured and used in the range measurement. A source of fluid measuring path media under pressure forms a column of fluid measuring path media is projected from the ultrasonic transducer to impinge on the hot target to enhance the accuracy of range measurements by minimizing the effect of temperature gradients due to the heat radiated from said hot target in said measuring path and narrow the distribution of reflection echo amplitudes, provide a more stable range of measurements and improve precision of range measurement by enhancing the accuracy of speed of sound in the media measurement.