US3539980A - Underwater electroacoustic transducer which resists intense pressure - Google Patents
Underwater electroacoustic transducer which resists intense pressure Download PDFInfo
- Publication number
- US3539980A US3539980A US779938A US3539980DA US3539980A US 3539980 A US3539980 A US 3539980A US 779938 A US779938 A US 779938A US 3539980D A US3539980D A US 3539980DA US 3539980 A US3539980 A US 3539980A
- Authority
- US
- United States
- Prior art keywords
- transducer
- housing
- plate
- pressure
- resists
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 230000002093 peripheral effect Effects 0.000 description 14
- 229910000831 Steel Inorganic materials 0.000 description 12
- 239000012530 fluid Substances 0.000 description 12
- 239000010959 steel Substances 0.000 description 12
- 229920001971 elastomer Polymers 0.000 description 11
- 239000000463 material Substances 0.000 description 10
- 239000007788 liquid Substances 0.000 description 6
- 229920002379 silicone rubber Polymers 0.000 description 5
- 239000004945 silicone rubber Substances 0.000 description 4
- 239000000919 ceramic Substances 0.000 description 3
- 239000003921 oil Substances 0.000 description 3
- 201000009032 substance abuse Diseases 0.000 description 3
- 239000004568 cement Substances 0.000 description 2
- 239000007789 gas Substances 0.000 description 2
- 230000003534 oscillatory effect Effects 0.000 description 2
- 238000007789 sealing Methods 0.000 description 2
- 239000007787 solid Substances 0.000 description 2
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Substances O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 2
- UDQTXCHQKHIQMH-KYGLGHNPSA-N (3ar,5s,6s,7r,7ar)-5-(difluoromethyl)-2-(ethylamino)-5,6,7,7a-tetrahydro-3ah-pyrano[3,2-d][1,3]thiazole-6,7-diol Chemical compound S1C(NCC)=N[C@H]2[C@@H]1O[C@H](C(F)F)[C@@H](O)[C@@H]2O UDQTXCHQKHIQMH-KYGLGHNPSA-N 0.000 description 1
- 239000004944 Liquid Silicone Rubber Substances 0.000 description 1
- 239000004359 castor oil Substances 0.000 description 1
- 235000019438 castor oil Nutrition 0.000 description 1
- 229940125936 compound 42 Drugs 0.000 description 1
- 238000010276 construction Methods 0.000 description 1
- 239000013013 elastic material Substances 0.000 description 1
- 238000004880 explosion Methods 0.000 description 1
- ZEMPKEQAKRGZGQ-XOQCFJPHSA-N glycerol triricinoleate Natural products CCCCCC[C@@H](O)CC=CCCCCCCCC(=O)OC[C@@H](COC(=O)CCCCCCCC=CC[C@@H](O)CCCCCC)OC(=O)CCCCCCCC=CC[C@H](O)CCCCCC ZEMPKEQAKRGZGQ-XOQCFJPHSA-N 0.000 description 1
- HFGPZNIAWCZYJU-UHFFFAOYSA-N lead zirconate titanate Chemical compound [O-2].[O-2].[O-2].[O-2].[O-2].[Ti+4].[Zr+4].[Pb+2] HFGPZNIAWCZYJU-UHFFFAOYSA-N 0.000 description 1
- 229910052451 lead zirconate titanate Inorganic materials 0.000 description 1
- 239000002184 metal Substances 0.000 description 1
- 230000001681 protective effect Effects 0.000 description 1
- 230000035939 shock Effects 0.000 description 1
- 229920002545 silicone oil Polymers 0.000 description 1
Images
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B06—GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS IN GENERAL
- B06B—METHODS OR APPARATUS FOR GENERATING OR TRANSMITTING MECHANICAL VIBRATIONS OF INFRASONIC, SONIC, OR ULTRASONIC FREQUENCY, e.g. FOR PERFORMING MECHANICAL WORK IN GENERAL
- B06B1/00—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency
- B06B1/02—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy
- B06B1/06—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction
- B06B1/0607—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using multiple elements
- B06B1/0611—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using multiple elements in a pile
- B06B1/0618—Methods or apparatus for generating mechanical vibrations of infrasonic, sonic, or ultrasonic frequency making use of electrical energy operating with piezoelectric effect or with electrostriction using multiple elements in a pile of piezo- and non-piezoelectric elements, e.g. 'Tonpilz'
Definitions
- the term intense pressure implies pressures in the order of 3000-3500 (or more) pounds per square inch. However, the invention is not limited to these or any other specific values. These intense pressures might occur responsive to underwater explosions. They also occur in very deep water, and perhaps elsewhere. Obviously, the converse is also truethe transducer should be able to operate equally well at the other end of the scale, where ambient pressure is negligible, as in gases or shallow liquids. Otherwise, the transducer would not function equally well over the entire range through which it passes, as when it is lowered from the surface to deep water.
- Transducers constructed according to the teachings of this invention find many uses, one of which may be on a submarine. When so used, the transducer may be partly recessed within a hull or deck so that its only exposed part is a plate mounted flush on the deck. If so, the transducer must withstand the abuse which occurs when people walk on it or drag heavy objects over it. Still other design considerations will readily occur to those skilled in the art.
- the preferred transducer design utilizes a vibratile plate piston driven by a stack of piezoelectric elements. These elements mechanicaly vibrate the plate to generate an acoustic power which is transferred to any gas or liquid surrounding the transducer.
- a transducer of this type may be found in U.S. Patent No. 3,328,751.
- an object of this invention is to provide new and improved underwater transducers which are able to withstand intense pressures.
- an object is to provide such electroacoustic transducers having improved shock resistance characteristics irrespective of the surrounding pressures.
- an object is to provide transducers having means for equalizing pressures inside and outside the transducer.
- Another object of this invention is to provide rugged transducers which can withstand abuse resulting from people walking on it and dragging heavy objects over it.
- a piezoceramic transducer assembly floating in a silicone rubber cradle.
- a rigid steel housing filled with a sound transmitting oil, surrounds the rubber cradle.
- the oil fills all voids within the transducer and housing.
- a rubber or other flexible member exposed to surrounding ambient pressure expands or contracts to increase or decrease the pressure of the oil within the transducer and thereby equalize the pressure inside the housing with the pressure outside the housing. Since there is a zero pressure differential between the inside and outside of the housing, the transducer does not experience intensive crushing forces.
- FIG. 1 is a cross-sectional view of a first embodiment of the invention featuring a flexible window for transmitting vibrations from the transducer into the associated medium and for equalizing pressures within and without the housing;
- FIG. 2 is a cross-sectional view of a second embodiment of the invention featuring a steel window for transmitting vibrations and a flexible sleeve for equalizing pressure.
- Both of the embodiments of the invention include essentlally the same structure, which may be generally described as a transducer 20 and a cradle 21 of elastic material inside a rugged protective housing 23.
- the transducer 20 includes a stack of piezoceramic elements 24-27 positioned between the back of a. vibratile plate 28 and the front of an inertial mass element 29 which are held together by a stress bolt 30.
- the piezoelectric material 24-27 may be a stack of coaxially positioned ceramic rings made of any known material, such as a polarized lead zirconate titanate. Suitable cement may be used to help hold the piezoelectric assembly together.
- the ceramic rings are separated by electrodes joining like polarities of the adjacent piezoelectric material.
- the electrodes of one polarity (say positive) are connected together by a first wire, as at 31.
- the electrodes of the other polarity (negative in this case) are connected together by a second wire, as at 32.
- These wires 3.1, 32 are connected to a cable 33 via insulated terminals 34, 35.
- a massive end plate 36 includes a cavity 37 where connections may be made, or changed, between the terminals 34 and 35. This cavity 37 is closed by a cover plate 38 which may be bolted in place.
- An O-ring 39 provides a hermetic seal between plates 36, 38.
- a waterproof molded rubber section 40 seals the cable 33 to the cover plate 38 and encloses the terminals 35.
- the transducer assembly floats in a cradle of silicone rubber. That cradle is protected by a strong and rugged steel. housing or case which is spaced away from and surrounds the peripheral portions of the vibratile plate 28 and the inertial mass element 29.
- the housing 23 is made of a strong, heavy walled steel tube 41 welded to the massive end plate 36 which surrounds the back of the inertial mass element 29. Then the assembled transducer 20 is slipped into the open end of the housing 23. Thereafter, the housing may he stood on its end plate 36, and an uncured liquid silicone rubber compound 42 is poured into the space between the housing 23 and the transducer 20, after which the rubber may be cured in any kn wn manner.
- the peripheral and back portions of the inertial mass element 29 are flexibly bonded to the steel housing 23 and back plate 36', via a resilient rubber cradle mount 21.
- a resilient rubber cradle mount 21 To help anchor the inertial mass 29 and lock it in place, it has an annular groove 43 which fills with the liquid rubber.
- An alternative construction would be to pre-form a rubber cap, as shown at 42, which is snapped over the inertial mass element 29 before the transducer is slipped into the steel housing 23. Cement may be used to seal the rubber cap 42 to the mass 29 and the steel housing 23.
- a resilient annular collar 45 is fitted into the peripheral space between the open end of the housing 23 and the vibratile piston plate 28.
- this collar 45 is a material having a very low coeflicient of friction, such as a silicone rubber. There should not be any appreciable loss of mechanical energy at the interface between the plate piston 28 and the resilient collar 45.
- a plate 46 is attached, in front of the vibratile plate, to the housing 23 by means of bolts 47, 48.
- the plate 46 rests against the end portion of the resilient collar 45 in order to provide a positive axial location of the transducer 20.
- an O-ring 49 is compressed between the plate 46 and the end of the steel tube 41.
- the plate 46 includes a sound transparent window or a central opening closed by a rubber or other flexible diaphragm 51 molded therein.
- Means are provided for maintaining an equilibrium of pressure between the inside and the outside of the transducer assembly. To do this, all voids or cavities inside the transducer are interconnected by communicating passageways. For example, the collar 45 is pierced by a passageway 53, and the vibratile plate piston 28 is pierced by a passageway 54. These passageways and the associated cavities are, in turn, accessible to the outside of housing 23 via an opening which is sealed by a tapered, threaded plug 55.
- the plug 55 is removed, and the housing 23 is evacuated. Then, a sound transmitting fluid is injected, under a slight positive pressure, into the opening at 55. The sound transmitting fluid flows into the housing, through all communicating passageways, and into all trapped enclosures, cavities, or voids. The transducer is completely filled, and the diaphragm 51 has a slight bulge. Then, the plug 55 is turned into place to seal the housing and retain the fluid. While any of many suitable sound transmitting fluids may be used, I prefer to use a silicone oil or castor oil.
- FIG. 2 is essentially the same as that of FIG. 1 except that the plate 46 is replaced by a solid steel plate 46a. Instead of a window filled by a molded resilient diaphragm 51, the plate 46a has an undercut region 59. Owing to the differential in plate thickness, the region 59 functions efliciently as a sound transmitting window. Nevertheless, the solid, unbroken outer surface of the steel plate 46a is not damaged by the mechanical abuses which may occur, as when people walk on it or drag heavy objects over it.
- the plate 46a is provided with a tapped opening plug 60.
- a resilient sleeve 61 (which could be rubber) surrounds the steel walled tube 41a.
- Sleeve 61 is clamped in place on tube 41a by means of metal bands 62, 63 at either end.
- a small orifice 64 provides a pressure communicating passageway between the inside of the housing Wall 41a and the inside of the resilient sleeve 61.
- the plug 60 is removed, and the transducer housing is evacuated. Thereafter, a sound transmitting fluid is introduced under positive pressure. All entrapped spaces are filled until the resilient sleeve 61 bulges. Then, the plug 60 is replaced.
- An electroacoustic transducer comprising a vibratile plate member having a front, back, and peripheral portion, an inertial mass member having a front, back, and peripheral portion, electromechanical oscillatory force generating means operatively connected between the back of said vibratile plate member and the front of said inertial member, a rigid housing structure having an inner peripheral wall portion spaced away from and surrounding said peripheral portions of said vibratile plate member and said inertial mass member, the back of said housing being spaced away from and enclosing the back of said inertial member, and resilient cradle means comprising a compliant material filling all of the clearance space between said housing structure and the peripheral portion of said vibratile plate member and the peripheral and back portions of the inertial member.
- the transducer of claim 1 and sound conducting liquid means completely filling all air space within the rigid housing.
- An electroacoustic transducer comprising a vibratile plate member having a peripheral portion, an inertial mass member having a peripheral portion, electromechanical oscillatory force generating means operatively connected between said vibratile plate member and said inertial member, a rigid housing structure having an inner peripheral wall portion spaced away from and surrounding said peripheral portions of said vibratile plate member and said inertial mass member, resilient cradle means comprising a compliant material filling most of the clearance space between said housing structure and the peripheral portions of said vibratile plate member and inertial member, said rigid housing structure being closed at one end, said inertial member being located near and spaced away from said closed end, said compliant material filling most of the space between said inertial member and the closed end of said housing structure, the other end of said housing structure being open, waterproof sealing means including a sound transparent window for closing said open end, wherein said sound transparent window is a rigid plate.
- transducer of claim 6 and means comprising a flexible walled enclosure surrounding a portion of said rigid housing structure, an orifice through the wall of said housing structure communicating between the inner space inside said rigid housing structure and the space within said flexible walled enclosure surrounding said housing structure, and sound conducting fluid means filling all air space inside said flexible walled enclosure and said rigid housing, said fluid communicating through said orifice and completely filling said flexible walled enclosure.
- An intense pressure resistant transducer assembly comprising transducer means floating in a resilient cradle surrounded and protected by a rigid housing, sound transmitting fluid filling all voids within said rigid housing, and means for transmitting ambient pressure surrounding said assembly to said fluid, thereby equalizing the pressure inside the housing with the pressure outside the housing.
- An intense pressure resistant transducer assembly comprising transducer means floating in a resilient cradle surrounded and protected by a rigid housing, sound transmitting fluid filling all voids within said rigid housing, means for transmitting ambient pressure surrounding said assembly to said fluid, thereby equalizing the pressure inside the housing with the pressure outside the housing, wherein said transducer means comprises, in series, a vibratile plate piston, a piezoelectric material structure and an inertial mass element held together by a stress bolt.
- said cradle comprises a resilient means interconnecting said plate and said housing and interconnecting said mass element and said housing.
- said ambient pressure transmitting means comprises a sound transmitting window adjacent said vibratile plate piston.
- said ambient pressure transmitting means comprises a resilient sleeve at least partially surrounding said rigid housing.
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- Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Transducers For Ultrasonic Waves (AREA)
Description
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US77993868A | 1968-11-29 | 1968-11-29 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3539980A true US3539980A (en) | 1970-11-10 |
Family
ID=25118059
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US779938A Expired - Lifetime US3539980A (en) | 1968-11-29 | 1968-11-29 | Underwater electroacoustic transducer which resists intense pressure |
Country Status (1)
Country | Link |
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US (1) | US3539980A (en) |
Cited By (22)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3769532A (en) * | 1970-11-06 | 1973-10-30 | B Tocquet | Mechanical decoupling device for attachment to electroacoustic transducers |
US3974474A (en) * | 1973-06-04 | 1976-08-10 | General Electric Company | Underwater electroacoustic transducer construction |
US4068209A (en) * | 1974-11-08 | 1978-01-10 | Thomson-Csf | Electroacoustic transducer for deep submersion |
FR2361033A1 (en) * | 1976-08-03 | 1978-03-03 | France Etat | PIEZOELECTRIC TRANSDUCERS AND HIGH DEPTH SUBMERSIBLE ACOUSTICAL ANTENNAS |
US4100527A (en) * | 1975-02-27 | 1978-07-11 | Etat Francais | Multi-driver piezoelectric transducers with single counter-masses, and sonar antennas made therefrom |
US4183007A (en) * | 1978-02-22 | 1980-01-08 | Fischer & Porter Company | Ultrasonic transceiver |
US4223428A (en) * | 1971-11-24 | 1980-09-23 | The United States Of America As Represented By The Secretary Of The Navy | Method and apparatus for securing a ferroelectric stack to a weighted projection surface |
US4319345A (en) * | 1980-05-23 | 1982-03-09 | Halliburton Company | Acoustic well-logging transmitting and receiving transducers |
US4364117A (en) * | 1980-04-14 | 1982-12-14 | Edo Western Corporation | Shock-hardened, high pressure ceramic sonar transducer |
US4450544A (en) * | 1981-11-16 | 1984-05-22 | Sperry Corporation | Absorptive sonar baffle |
US4545041A (en) * | 1982-10-27 | 1985-10-01 | The United States Of America As Represented By The Secretary Of The Navy | Shock-hardened hydrophone |
US4674074A (en) * | 1984-10-23 | 1987-06-16 | Schoen Jr Oscar W | Saturated vapor pressure release mechanism |
GB2186152A (en) * | 1986-01-31 | 1987-08-05 | Graseby Dynamics Ltd | Mounting of sonic devices |
US4704709A (en) * | 1985-07-12 | 1987-11-03 | Westinghouse Electric Corp. | Transducer assembly with explosive shock protection |
US4821244A (en) * | 1985-11-30 | 1989-04-11 | Ferranti International Signal, Plc | Tubular acoustic projector |
FR2665814A1 (en) * | 1990-08-10 | 1992-02-14 | Thomson Csf | ELECTROACOUSTIC TRANSDUCER FOR IMMERSION AND COMPRISING A SYSTEM FOR AUTOMATIC COMPENSATION OF IMMERSION PRESSURE |
GB2252474A (en) * | 1991-01-31 | 1992-08-05 | Chang Chin Lu | Microphone handle |
EP0517557A1 (en) * | 1991-06-07 | 1992-12-09 | ETAT-FRANCAIS représenté par le DELEGUE GENERAL POUR L'ARMEMENT (DPAG) | Device to retain a loose underwater structure in case of an explosion |
US5491671A (en) * | 1984-04-26 | 1996-02-13 | Alliant Techsystems Inc. | Sonar transducer with unitary isolator |
RU168468U1 (en) * | 2016-11-29 | 2017-02-06 | Закрытое акционерное общество "Руспром" | RECEIVING HYDROPHONE |
GB2575693A (en) * | 2018-07-20 | 2020-01-22 | Univ Warwick | Flexural ultrasonic transducer |
WO2020016576A1 (en) * | 2018-07-20 | 2020-01-23 | The University Of Warwick | Ultrasonic transducer |
Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2983901A (en) * | 1945-04-16 | 1961-05-09 | Le Roy C Paslay | Crystal hydrophone |
US3199071A (en) * | 1961-04-20 | 1965-08-03 | Dynamics Corp America | Electroacoustic transducer construction suitable for operation in deep water |
US3230503A (en) * | 1962-06-22 | 1966-01-18 | Jr Jack Elliot | Transducer |
-
1968
- 1968-11-29 US US779938A patent/US3539980A/en not_active Expired - Lifetime
Patent Citations (3)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2983901A (en) * | 1945-04-16 | 1961-05-09 | Le Roy C Paslay | Crystal hydrophone |
US3199071A (en) * | 1961-04-20 | 1965-08-03 | Dynamics Corp America | Electroacoustic transducer construction suitable for operation in deep water |
US3230503A (en) * | 1962-06-22 | 1966-01-18 | Jr Jack Elliot | Transducer |
Cited By (26)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3769532A (en) * | 1970-11-06 | 1973-10-30 | B Tocquet | Mechanical decoupling device for attachment to electroacoustic transducers |
US4223428A (en) * | 1971-11-24 | 1980-09-23 | The United States Of America As Represented By The Secretary Of The Navy | Method and apparatus for securing a ferroelectric stack to a weighted projection surface |
US3974474A (en) * | 1973-06-04 | 1976-08-10 | General Electric Company | Underwater electroacoustic transducer construction |
US4068209A (en) * | 1974-11-08 | 1978-01-10 | Thomson-Csf | Electroacoustic transducer for deep submersion |
US4100527A (en) * | 1975-02-27 | 1978-07-11 | Etat Francais | Multi-driver piezoelectric transducers with single counter-masses, and sonar antennas made therefrom |
FR2361033A1 (en) * | 1976-08-03 | 1978-03-03 | France Etat | PIEZOELECTRIC TRANSDUCERS AND HIGH DEPTH SUBMERSIBLE ACOUSTICAL ANTENNAS |
US4183007A (en) * | 1978-02-22 | 1980-01-08 | Fischer & Porter Company | Ultrasonic transceiver |
US4364117A (en) * | 1980-04-14 | 1982-12-14 | Edo Western Corporation | Shock-hardened, high pressure ceramic sonar transducer |
US4319345A (en) * | 1980-05-23 | 1982-03-09 | Halliburton Company | Acoustic well-logging transmitting and receiving transducers |
US4450544A (en) * | 1981-11-16 | 1984-05-22 | Sperry Corporation | Absorptive sonar baffle |
US4545041A (en) * | 1982-10-27 | 1985-10-01 | The United States Of America As Represented By The Secretary Of The Navy | Shock-hardened hydrophone |
US5491671A (en) * | 1984-04-26 | 1996-02-13 | Alliant Techsystems Inc. | Sonar transducer with unitary isolator |
US4674074A (en) * | 1984-10-23 | 1987-06-16 | Schoen Jr Oscar W | Saturated vapor pressure release mechanism |
US4704709A (en) * | 1985-07-12 | 1987-11-03 | Westinghouse Electric Corp. | Transducer assembly with explosive shock protection |
US4821244A (en) * | 1985-11-30 | 1989-04-11 | Ferranti International Signal, Plc | Tubular acoustic projector |
GB2186152A (en) * | 1986-01-31 | 1987-08-05 | Graseby Dynamics Ltd | Mounting of sonic devices |
GB2186152B (en) * | 1986-01-31 | 1989-11-01 | Graseby Dynamics Ltd | Mounting of sonic devices |
FR2665814A1 (en) * | 1990-08-10 | 1992-02-14 | Thomson Csf | ELECTROACOUSTIC TRANSDUCER FOR IMMERSION AND COMPRISING A SYSTEM FOR AUTOMATIC COMPENSATION OF IMMERSION PRESSURE |
EP0473480A1 (en) * | 1990-08-10 | 1992-03-04 | Thomson-Csf | Electroacoustic transducer for use under water and comprising a system for automatically compensating the hydrostatic pressure |
GB2252474A (en) * | 1991-01-31 | 1992-08-05 | Chang Chin Lu | Microphone handle |
EP0517557A1 (en) * | 1991-06-07 | 1992-12-09 | ETAT-FRANCAIS représenté par le DELEGUE GENERAL POUR L'ARMEMENT (DPAG) | Device to retain a loose underwater structure in case of an explosion |
FR2677323A1 (en) * | 1991-06-07 | 1992-12-11 | France Etat Armement | DEVICE FOR LOCKING A FREE UNDERWATER STRUCTURE IN THE EVENT OF AN EXPLOSION. |
RU168468U1 (en) * | 2016-11-29 | 2017-02-06 | Закрытое акционерное общество "Руспром" | RECEIVING HYDROPHONE |
GB2575693A (en) * | 2018-07-20 | 2020-01-22 | Univ Warwick | Flexural ultrasonic transducer |
WO2020016563A1 (en) * | 2018-07-20 | 2020-01-23 | The University Of Warwick | Flexural ultrasonic transducer |
WO2020016576A1 (en) * | 2018-07-20 | 2020-01-23 | The University Of Warwick | Ultrasonic transducer |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
Owner name: MASSA, DONALD P., COHASSET, MA Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:STONELEIGH TRUST, THE;REEL/FRAME:005397/0016 Effective date: 19841223 Owner name: TRUSTEES FOR AND ON BEHALF OF THE D.P. MASSA TRUST Free format text: ASSIGN TO TRUSTEES AS EQUAL TENANTS IN COMMON, THE ENTIRE INTEREST.;ASSIGNORS:MASSA, DONALD P.;MASSA, CONSTANCE A.;MASSA, GEORGIANA M.;AND OTHERS;REEL/FRAME:005395/0942 Effective date: 19841223 Owner name: MASSA PRODUCTS CORPORATION, 80 LINCOLN STREET, HIN Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:DONALD P. MASSA TRUST;CONSTANCE ANN MASSA TRUST *;GEORGIANA M. MASSA TRUST;AND OTHERS;REEL/FRAME:005395/0954 Effective date: 19841223 Owner name: DELLORFANO, FRED M. JR. Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNOR:STONELEIGH TRUST, THE;REEL/FRAME:005397/0016 Effective date: 19841223 Owner name: MASSA PRODUCTS CORPORATION, 280 LINCOLN STREET, HI Free format text: ASSIGNMENT OF ASSIGNORS INTEREST.;ASSIGNORS:DONALD P. MASSA TRUST;CONSTANCE ANN MASSA TRUST;ROBERT MASSA TRUST;AND OTHERS;REEL/FRAME:005395/0971 Effective date: 19860612 |