Hypertension Diagnostics, Inc.

Pcb Piezotronics, Inc.

Apollo Research Corp.

Michael Terry Riggs

Charles F Chesney

Charles A Lemaire

Nicholas D Change

Dennis J Morgan

Eugene A O'Rourke

Fred Randall Thornton

Patrick Flanagan

Jerry G Chutkow

A method for fabricating a pressure-waveform sensor with a leveling support element. One embodiment provides a pressure-waveform sensor having a housing, a support element, and a piezoelectric element having a first end secured between the support element and the housing, and a second end in a cantilevered orientation. The support element and the piezoelectric element together form a plurality of support regions to level the piezoelectric element and relative to the housing. In some embodiments, the support element includes a ring having three slots spaced apart on one face of the ring, or one or more support regions formed with a shim having a thickness equal to a thickness of the piezoelectric device, or support regions that are integral to the support element. Another aspect provides a method for fabricating a pressure-waveform sensor. The method includes the steps of forming a housing structure with an inner lip, and supporting a cantilevered piezoelectric element with a support structure such that contact is made with the inner lip at a plurality of points in order to level the piezoelectric element relative to the inner lip.

Method for fabricating a pressure-wave sensor with a leveling support element

A method and an apparatus for fabricating a pressure-waveform sensor with a leveling support element. One embodiment provides a pressure-waveform sensor having a housing, a support element, and a piezoelectric element having a first end secured between the support element and the housing, and a second end in a cantilevered orientation. The support element and the piezoelectric element together form a plurality of support regions to level the piezoelectric element and relative to the housing. In some embodiments, the support element includes a ring having three slots spaced apart on one face of the ring, or one or more support regions formed with a shim having a thickness equal to a thickness of the piezoelectric device, or support regions that are integral to the support element. Another aspect provides a method for fabricating a pressure-waveform sensor. The method includes the steps of forming a housing structure with an inner lip, and supporting a cantilevered piezoelectric element with a support structure such that contact is made with the inner lip at a plurality of points in order to level the piezoelectric element relative to the inner lip.

Pressure-wave sensor with a leveling support element

Method and apparatus for fabricating a pressure-wave sensor with a leveling support element

A method and a pulse pressure sensor for sensing an arterial pulse pressure waveform. In one embodiment, the pulse pressure sensor includes a housing, a diaphragm, a piezoelectric device, and a self-contained amplifier. The skin-contact diaphragm is attached across a recess or opening in the housing. The piezoelectric device has a first portion mounted in a fixed relationship to the housing and a second portion displacementally coupled to the diaphragm. The solid-state amplifier has a signal input coupled to the piezoelectric device, wherein the piezoelectric device and amplifier together have a frequency response at least including a range from below approximately 0.1 hertz to above approximately 250 hertz. In one such embodiment, the housing and the skin-contact diaphragm of the sensor are stainless steel. In one such embodiment, the diaphragm has a skin-contact surface with a skin-contact dimension of between approximately 0.4 inch and 0.6 inch. In one embodiment, the sensor includes a solid-state amplifier that includes a high-input-impedance MOSFET input stage having an input resistance high enough to provide a frequency response that extends below approximately 0.1 hertz.

Sensor and method for sensing arterial pulse pressure

Reflex measuring device, and method

A pressure generator for testing and calibrating pressure transducers has a body with an internal chamber. The chamber is filled with a liquid, statically pressurized. A piston is mounted in the chamber on a suspension member. A coil, mounted to move with the piston, is arranged in a magnetic field. The coil is supplied with varying current to cause the piston to oscillate or dither in the chamber. Such oscillation creates a dynamic pressure which is superimposed on the static pressure. Openings are provided in the body to receive the sensing end of one or more pressure transducers.

Dynamic pressure generator

A calibration arrangement in combination with ammunition testing apparatus comprising an elongated test barrel and a piezoelectric transducer mounted in the barrel and having a contoured end surface in operative contact with the outer wall surface of a cartridge to be tested. The transducer converts pressure changes into electrical signals which are translated through an amplifier to a voltmeter for readout. The calibration arrangement includes a pressure tube element adapted to fit in the test barrel with one end in pressure-tight relation with the interior of an empty cartridge casing held in the test barrel and with the other end of the tube adjacent the opposite end of the test barrel. The tube is held by a retaining assembly against lengthwise movement in the test barrel. A conduit connects a source of known hydraulic pressure to the tube for introducing known calibration pressure to the interior of the cartridge casing. As a result, both test firing and calibration can be performed in the same test barrel.

Pressure transducer calibration

A transducer for converting pressure changes into electrical signals wherein the pressure changes act on one surface of a relatively thin wall, such as pressure changes within a tube. A piston means on one end of a transducer housing and integral therewith has a contoured end surface conforming to the other surface of the wall opposite the surface on which pressure changes act. When the pressure changes are within a tube, for example within a cartridge casing in ammunition testing, the contoured end surface is concave. Piezoelectric crystal elements rigidly positioned within the transducer are deformed when pressure is applied through the wall to the contoured end surface of the piston means, and an output electrical signal is produced proportional to the applied pressure. Installation of the transducer in a test body is facilitated by a captive retaining nut rotatably connected on the transducer housing and having external threads for connecting in the test body. An alignment guide is carried by the transducer and engages the test body in a manner providing precise rotational alignment and permitting depth adjustment of the contoured end surface.

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Batavia, NY, United States of America

Michael Terry Riggs