US3578995A - Electroacoustic transducers of the bilaminar flexural vibrating type - Google Patents
Electroacoustic transducers of the bilaminar flexural vibrating type Download PDFInfo
- Publication number
- US3578995A US3578995A US859677A US3578995DA US3578995A US 3578995 A US3578995 A US 3578995A US 859677 A US859677 A US 859677A US 3578995D A US3578995D A US 3578995DA US 3578995 A US3578995 A US 3578995A
- Authority
- US
- United States
- Prior art keywords
- transducer
- diaphragm
- disc
- housing structure
- housing
- 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
- 239000000919 ceramic Substances 0.000 claims abstract description 18
- 230000002093 peripheral effect Effects 0.000 claims description 3
- 229910052782 aluminium Inorganic materials 0.000 claims description 2
- XAGFODPZIPBFFR-UHFFFAOYSA-N aluminium Chemical compound [Al] XAGFODPZIPBFFR-UHFFFAOYSA-N 0.000 claims description 2
- 229910052751 metal Inorganic materials 0.000 claims description 2
- 239000002184 metal Substances 0.000 claims description 2
- 239000000615 nonconductor Substances 0.000 claims 1
- 238000007789 sealing Methods 0.000 claims 1
- 230000000712 assembly Effects 0.000 abstract description 3
- 238000000429 assembly Methods 0.000 abstract description 3
- 238000004519 manufacturing process Methods 0.000 description 8
- 238000013461 design Methods 0.000 description 4
- 239000004593 Epoxy Substances 0.000 description 2
- 239000004568 cement Substances 0.000 description 2
- 238000001514 detection method Methods 0.000 description 2
- 239000000463 material Substances 0.000 description 2
- 238000000034 method Methods 0.000 description 2
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- DUPIXUINLCPYLU-UHFFFAOYSA-N barium lead Chemical compound [Ba].[Pb] DUPIXUINLCPYLU-UHFFFAOYSA-N 0.000 description 1
- JRPBQTZRNDNNOP-UHFFFAOYSA-N barium titanate Chemical compound [Ba+2].[Ba+2].[O-][Ti]([O-])([O-])[O-] JRPBQTZRNDNNOP-UHFFFAOYSA-N 0.000 description 1
- 229910002113 barium titanate Inorganic materials 0.000 description 1
- 150000001875 compounds Chemical class 0.000 description 1
- 239000000835 fiber Substances 0.000 description 1
- 239000011888 foil Substances 0.000 description 1
- 238000009434 installation Methods 0.000 description 1
- 239000011810 insulating material Substances 0.000 description 1
- 239000012774 insulation material Substances 0.000 description 1
- 238000012423 maintenance Methods 0.000 description 1
- 238000012986 modification Methods 0.000 description 1
- 230000004048 modification Effects 0.000 description 1
- 239000002245 particle Substances 0.000 description 1
- 238000004382 potting Methods 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 238000012360 testing method Methods 0.000 description 1
Images
Classifications
-
- H—ELECTRICITY
- H04—ELECTRIC COMMUNICATION TECHNIQUE
- H04R—LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; DEAF-AID SETS; PUBLIC ADDRESS SYSTEMS
- H04R17/00—Piezoelectric transducers; Electrostrictive transducers
-
- G—PHYSICS
- G08—SIGNALLING
- G08B—SIGNALLING OR CALLING SYSTEMS; ORDER TELEGRAPHS; ALARM SYSTEMS
- G08B13/00—Burglar, theft or intruder alarms
- G08B13/16—Actuation by interference with mechanical vibrations in air or other fluid
- G08B13/1609—Actuation by interference with mechanical vibrations in air or other fluid using active vibration detection systems
Definitions
- a button transducer comprises a metallic diaphragm concentrically bonded to a piezoelectric ceramic disc.
- a plurality of types of annular housings are provided for clamping and terminating the periphery of the diaphragm, each housing type having a central opening with a different diameter therein.
- the bonded diaphragm-disc assemblies are measured for resonant frequency, and the housing type is selected to tune the bonded assembly to have a predetermined resonant frequency.
- This invention relates to new and improved electroacoustic transducers, and more particularly to low cost, mass produced transducers especially-although not exclusively-adapted for use in burglar alarm systems.
- an object of the invention is to provide new and improved transducers of the described type.
- an object is to provide low-cost transducers which have the precision heretofore available only in high priced transducers.
- Another object is to provide a transducer design that may initially have very wide production tolerances which may easily be reduced to acceptable tolerances after production in order to enable a final production which is equivalent to production with very tight initial tolerances.
- Another object is to provide very small, unobtrusive transducers which do not attract an undue amount of attention.
- an object is to provide self-checking transducers which send an alarm if subjected to tampering. Yet another object is to provide for enabling easy replacement of transducers for either maintenance or testing purposes.
- Still another object of the invention is to provide a simple transducer which may be made quickly or easily on general purpose tooling.
- an object is to reduce the capital cost of entry into the field.
- Another object of this invention is to design a low-cost transducer for operating in the high audio or ultrasonic region.
- Yet another object of this invention is to provide a low-cost production method for adjusting the resonant frequency of large quantities of transducers after they have been produced.
- Still another object of this invention is to provide a low-cost transducer which may be universally used in a great variety of applications.
- a small universal transducer is assembled as a button to be added to any other structure with which it is to be used.
- the transducer button is made very small in diameter so that the design is particularly useful in connection with ultrasonic devices used as proximity indicators or intrusion detectors where detection of the device by the intruder would foil the system.
- the entire assembly including associated electrical components are built into a small cylindrical structure with a multiterminal plug connector at one end for simple plug-in installation in the field. Two of the terminals are internally connected to provide a continuity alarm circuit which is broken when the plug connector is removed from a socket.
- FIG. 1 is a perspective view of an exemplary transducer, of the described type, attached to a canister housing having a multiterminal plug connection;
- FIG. 2 is a plan view of the canister looking down upon the top of FIG. 1, along the line 2-2;
- FIG. 3 is a sectional view of the transducer taken along the line 3-3 of FIG. 1;
- FIG. 4 is a cross-sectional view taken along line 4-4 (FIG. 2) which illustrates the attachment of the transducer of FIG. 2 to a compact canister housing containing electronic components and a multiterminal electrical connecting plug for permitting convenient plug-in connections; and
- FIG. 5 is a bottom plan view of FIG. 4.
- This invention is concerned with improvements in the design of a small, inexpensive electroacoustic transducer 10 (FIG. 1) which employs a bilaminar circular disc assembly as the active vibratile diaphragm structure.
- This transducer is manufactured as a small button which may be press fitted or otherwise attached to any suitable housing, as it is here shown attached to the top of a canister housing 11.
- the canister may house any associated equipment, such as electrical components, for example.
- Another side of the canister may carry a multiterminal plug 12 for enabling the transducer and canister assembly to be plugged into a convenient outlet socket.
- buttons transducer could be pressed into the cabinet or chassis of any associated electronic equipment.
- the reference character 15 identifies a circular diaphragm preferably made of a rigid lightweight metal, such as aluminum. Attached to the central portion of the diaphragm 15 is a disc 16 of transducer material such as a polarized ceramic (for example, this may be barium titanate or lead zirconate titanate-both of which are well known in the art).
- the ceramic disc 16 has a metallized electrode surface on each face.
- the bonding material used to attach disc 16 to diaphragm 15 is preferably a rigid electrically conducting cement, such as an epoxy containing silver particles.
- the diaphragm-transducer disc assembly 15, 16 is cemented into a peripheral recessed portion 17 of a massive ring or annular housing 18. Again, an electrically conductive epoxy or other suitable cement may be used to attach diaphragm 15 to ring 18; thus, the diaphragm disc 15 closes the top of the chamber 19. Opposite the diaphragm 15, the housing structure 18 contains another recessed chamber portion 21. These two chambers are separated by a closure disc 22 which may be made of insulation material.
- a terminal lug 23 is attached to the disc 22 by means of a rivet 24.
- Another terminal lug 25 is attached to the housing 18 by a drive screw 28.
- the lug 23 makes electrical connection with one side of the piezoelectric disc 16, and the return circuit is via the housing, which makes electrical connection to the diaphragm 15 and the electrode surface of the piezoelectric disc 16.
- the resonant frequency of the assembled vibratile structure varies with changes in the thickness of the diaphragm and ceramic. It also varies with the diameter of the opening through the ring clamp housing 18, which determines the clamped diameter of the disc. As a result, I have found that it is necessary to make the thickness of the diaphragm 15 less than one-fifteenth of its diameter. During vibration in the clamped disc mode of operation, only about one-third of the unclamped central area of the diaphragm develops a fibre stress of the same electrical polarity. Therefore, the area of the ceramic disc 16 should preferably be less than one-half of the total unclamped area of the diaphragm 15. I have also found that, to obtain efficient operation, the diameter of the ceramic disc 16 has to be more than 10 times the thickness of the ceramic.
- housings with the larger openings D are selected to be used with the higher frequency groups of diaphragm-disc structures.
- Housings with smaller openings D are combined with diaphragm and ceramic disc assemblies displaying the lower resonant frequencies.
- FIGS. 4 and 5 illustrate one application in which a button transducer assembly is attached to a canister 11.
- the housing 18 of the transducer is applied to close one end of a cylindrical tube 11.
- the electronic components 30 and 31, required for the operation of the transducer, are mounted in the canister 11.
- these particular components are here shown by way of example only. Any suitable components may be mounted here.
- the terminals 23 and 25, from the button transducer, are connected by wires to the components 30, 31.
- the open end of the tubular canister housing 11 is closed by a disc of insulating material 32 fitted with a number of connector pins 33, 34, 35, 36 and 37'which act as a plug-in connector.
- the pin 33 is slightly larger than the other pins in order to ensure proper orientation when the unit is plugged into the associated socket.
- a volume control 40 is assembled in the center inside surface of the-insulated disc member 32.
- a countersunk slotted shaft 41 enables adjustment of the gain of the system.
- a self-checking alarm system is provided to enable immediate detection if the unit is removed or tampered with in the field.
- a short-circuiting or continuity connection 42 is made between pins 36 and 37. This short circuit provides electrical continuity for a tamperproof circuit connected to the corresponding socket terminals. If the unit is removed, the shorting strip 42 no longer provides the continuity for the tamperproof circuit, and an alarm 45 may be given to indicate this fact.
- a potting compound may be' poured into the canister in order to consolidate the structure.
- An. electroacoustic transducer comprising a circular diaphragm having a diameter which is more than 15 times its thickness, acircular polarized piezoelectric ceramic disc having'a diameter which is more than 10 times its thickness, bonding means for holding said diaphragm and disc rigidly bound together in concentric face-to-face relationship, the area of said ceramic disc being no greater than one-half the area of said diaphragm, an annular housing structure having an opening at one end for locating and holding said diaphragm, rigid bonding means between the peripheral surface of said diaphragm and the surface in said opening in said annular housing, and electrical connection means attached to a circular face surface of said polarized ceramic disc.
- transducer of claim 1 further characterized in that said housing structure has a second opening at its other end and closure means comprising a circular insulating disc placed between said openingsto close said housing structure and seal off a compartment within which said ceramic disc is conminals attached thereto for establishing electrical connections from the outside of the assembled canister housing structure to the interior of said canister housing structure,
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- Physics & Mathematics (AREA)
- Engineering & Computer Science (AREA)
- Acoustics & Sound (AREA)
- Signal Processing (AREA)
- General Physics & Mathematics (AREA)
- Piezo-Electric Transducers For Audible Bands (AREA)
Abstract
Description
Claims (7)
Applications Claiming Priority (1)
Application Number | Priority Date | Filing Date | Title |
---|---|---|---|
US85967769A | 1969-09-22 | 1969-09-22 |
Publications (1)
Publication Number | Publication Date |
---|---|
US3578995A true US3578995A (en) | 1971-05-18 |
Family
ID=25331480
Family Applications (1)
Application Number | Title | Priority Date | Filing Date |
---|---|---|---|
US859677A Expired - Lifetime US3578995A (en) | 1969-09-22 | 1969-09-22 | Electroacoustic transducers of the bilaminar flexural vibrating type |
Country Status (1)
Country | Link |
---|---|
US (1) | US3578995A (en) |
Cited By (10)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3736632A (en) * | 1971-03-18 | 1973-06-05 | Dynamics Corp Massa Div | Method of making an electroacoustic transducer |
US3761956A (en) * | 1970-10-01 | 1973-09-25 | Nittan Co Ltd | Sound generating device |
US3879726A (en) * | 1972-03-20 | 1975-04-22 | Mallory & Co Inc P R | Audible alarm unit |
US3890513A (en) * | 1974-02-14 | 1975-06-17 | Systron Donner Corp | Acoustic transducer |
US4172253A (en) * | 1972-04-19 | 1979-10-23 | Hermans Albert L | Controlled wave pattern ultrasonic burglar alarm |
US4273399A (en) * | 1979-11-05 | 1981-06-16 | Amp Incorporated | Transducer supporting and contacting means |
US4823042A (en) * | 1986-07-18 | 1989-04-18 | Rich-Mar Corporation | Sonic transducer and method for making the same |
US5118981A (en) * | 1988-09-09 | 1992-06-02 | Nissan Motor Company, Limited | Piezoelectric sensor for monitoring kinetic momentum |
US20040112706A1 (en) * | 2002-12-11 | 2004-06-17 | Kuo-Tsi Chang | Ultrasonic clutch |
US20120113758A1 (en) * | 2009-07-23 | 2012-05-10 | Valeo Schalter Und Sensoren Gmbh | Diaphragm and process for producing a diaphragm for an ultrasonic transducer |
Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2069633A (en) * | 1935-10-25 | 1937-02-02 | Gen Electric | Frequency determining unit for piezoelectric crystal controlling oscillators |
US2430013A (en) * | 1942-06-10 | 1947-11-04 | Rca Corp | Impedance matching means for mechanical waves |
US3074034A (en) * | 1959-01-15 | 1963-01-15 | Litton Systems Inc | Disk resonator |
US3166730A (en) * | 1959-09-29 | 1965-01-19 | Jr James R Brown | Annular electrostrictive transducer |
US3321189A (en) * | 1964-09-10 | 1967-05-23 | Edison Instr Inc | High-frequency ultrasonic generators |
US3331970A (en) * | 1964-09-29 | 1967-07-18 | Honeywell Inc | Sonic transducer |
US3380019A (en) * | 1967-01-27 | 1968-04-23 | Navy Usa | Pressure-gradient hydrophone |
US3401275A (en) * | 1966-04-14 | 1968-09-10 | Clevite Corp | Composite resonator |
-
1969
- 1969-09-22 US US859677A patent/US3578995A/en not_active Expired - Lifetime
Patent Citations (8)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US2069633A (en) * | 1935-10-25 | 1937-02-02 | Gen Electric | Frequency determining unit for piezoelectric crystal controlling oscillators |
US2430013A (en) * | 1942-06-10 | 1947-11-04 | Rca Corp | Impedance matching means for mechanical waves |
US3074034A (en) * | 1959-01-15 | 1963-01-15 | Litton Systems Inc | Disk resonator |
US3166730A (en) * | 1959-09-29 | 1965-01-19 | Jr James R Brown | Annular electrostrictive transducer |
US3321189A (en) * | 1964-09-10 | 1967-05-23 | Edison Instr Inc | High-frequency ultrasonic generators |
US3331970A (en) * | 1964-09-29 | 1967-07-18 | Honeywell Inc | Sonic transducer |
US3401275A (en) * | 1966-04-14 | 1968-09-10 | Clevite Corp | Composite resonator |
US3380019A (en) * | 1967-01-27 | 1968-04-23 | Navy Usa | Pressure-gradient hydrophone |
Cited By (12)
Publication number | Priority date | Publication date | Assignee | Title |
---|---|---|---|---|
US3761956A (en) * | 1970-10-01 | 1973-09-25 | Nittan Co Ltd | Sound generating device |
US3736632A (en) * | 1971-03-18 | 1973-06-05 | Dynamics Corp Massa Div | Method of making an electroacoustic transducer |
US3879726A (en) * | 1972-03-20 | 1975-04-22 | Mallory & Co Inc P R | Audible alarm unit |
US4172253A (en) * | 1972-04-19 | 1979-10-23 | Hermans Albert L | Controlled wave pattern ultrasonic burglar alarm |
US3890513A (en) * | 1974-02-14 | 1975-06-17 | Systron Donner Corp | Acoustic transducer |
US4273399A (en) * | 1979-11-05 | 1981-06-16 | Amp Incorporated | Transducer supporting and contacting means |
US4823042A (en) * | 1986-07-18 | 1989-04-18 | Rich-Mar Corporation | Sonic transducer and method for making the same |
US5118981A (en) * | 1988-09-09 | 1992-06-02 | Nissan Motor Company, Limited | Piezoelectric sensor for monitoring kinetic momentum |
US20040112706A1 (en) * | 2002-12-11 | 2004-06-17 | Kuo-Tsi Chang | Ultrasonic clutch |
US6964327B2 (en) * | 2002-12-11 | 2005-11-15 | Kuo-Tsi Chang | Ultrasonic clutch |
US20120113758A1 (en) * | 2009-07-23 | 2012-05-10 | Valeo Schalter Und Sensoren Gmbh | Diaphragm and process for producing a diaphragm for an ultrasonic transducer |
US9311908B2 (en) * | 2009-07-23 | 2016-04-12 | Valeo Schalter Und Sensoren Gmbh | Diaphragm and process for producing a diaphragm for an ultrasonic transducer |
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Legal Events
Date | Code | Title | Description |
---|---|---|---|
AS | Assignment |
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: 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: DELLORFANO, FRED M. JR. 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, 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 |