# US 7,608,984 B2 · Motion amplification using piezoelectric element > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 7,608,984 B2 - Document ID: US7608984B2 - Status: Granted - Kind: B2 - Application number: 11/747,469 - Filed: 2007-05-11 - Published: 2007-11-29 - Granted: 2009-10-27 - Earliest claimed: 2006-05-15 - Assignees: Adaptivenergy, LLC - Inventors: David D. Wright - Web page: https://patentgrep.com/patent/US7608984B2 ## CPC - F04B 43/046: {with piezoelectric drive} - F04B 45/047: Pumps having electric drive - H04R 17/00: Piezoelectric transducers; Electrostrictive transducers (piezoelectric or electrostrictive elements in general H10N30/00; details of piezoelectric or electrostrictive motors, generators or positioners {H10N30/00}) - H10N 30/2047: {Membrane type} - F04B: POSITIVE-DISPLACEMENT MACHINES FOR LIQUIDS; PUMPS (machines for liquids, or pumps, of rotary-piston or oscillating-piston type F04C; non-positive-displacement pumps F04D; pumping of fluid by direct contact of another fluid or by using inertia of fluid to be pumped F04F) - H04R: LOUDSPEAKERS, MICROPHONES, GRAMOPHONE PICK-UPS OR LIKE ACOUSTIC ELECTROMECHANICAL TRANSDUCERS; ELECTRIC HEARING AIDS; PUBLIC ADDRESS SYSTEMS (producing sounds with frequency not determined by supply frequency G10K) - H10N: ELECTRIC SOLID-STATE DEVICES NOT OTHERWISE PROVIDED FOR ## Abstract A motion amplifier (22) comprises piezoelectric diaphragm (30) and drive electronics (26) for applying a drive signal to the piezoelectric diaphragm. The motion amplifier preferably comprises (in addition to the piezoelectric diaphragm) a reaction mass (34) connected to the piezoelectric diaphragm; a reacted mass (40) connected to the piezoelectric diaphragm; and, a reacted mass spring (50, 270) for resiliently carrying the reacted mass. Motion or displacement of the piezoelectric diaphragm (30) is amplified to produce a greater displacement or motion of an actuator region or surface (46) of the reacted mass (40). ## Claims ### Claim 1 A motion amplifier comprising: a piezoelectric diaphragm; a reaction mass connected to the piezoelectric diaphragm; a reacted mass connected to the piezoelectric diaphragm; a reacted mass spring for resiliently carrying the reacted mass; wherein a periphery of the piezoelectric diaphragm is held and carried by the reacted mass; wherein the reacted mass comprises a reacted mass cup which defines a reacted mass cavity, and wherein the reaction mass is suspended from the piezoelectric diaphragm in the reacted mass cavity. ### Claim 2 (depends on 1) The apparatus of claim 1, further comprising drive electronics for driving the piezoelectric diaphragm by generating and applying a drive signal to the piezoelectric diaphragm. ### Claim 3 (depends on 2) The apparatus of claim 2, wherein the drive electronics generates and applies a drive signal to the piezoelectric diaphragm to maintain the motion amplifier resonant at a predetermined frequency. ### Claim 4 (depends on 3) The apparatus of claim 3, wherein structure of the motion amplifier carried by the reacted mass spring has a resonant frequency f2, wherein the predetermined frequency is f2, and wherein the drive signal is generated to urge the motion amplifier to the frequency f2 as its operational frequency, thereby achieving peak amplitude displacement of the motion amplifier. ### Claim 5 (depends on 4) The apparatus of claim 4, wherein the resonant frequency f2 is related to a spring constant K2 of the reacted mass spring and a sum of masses of the reaction mass and the reacted mass. ### Claim 6 (depends on 2) The apparatus of claim 2, wherein the drive electronics generates the drive signal to maintain a predetermined phase angle between the drive signal and a signal indicative of displacement of the motion amplifier. ### Claim 7 (depends on 6) The apparatus of claim 6, wherein the drive electronics comprises a sensor for sensing displacement of the motion amplifier and for generating the signal indicative of displacement of the motion amplifier. ### Claim 8 (depends on 1) The apparatus of claim 1, further comprising: an amplifier base; and means for resiliently mounting the amplifier base relative to the outside world. ### Claim 9 (depends on 8) The apparatus of claim 8, wherein the amplifier base carries the piezoelectric diaphragm, the reaction mass, the reacted mass, and the reacted mass spring. ### Claim 10 (depends on 9) The apparatus of claim 9, wherein the reacted mass spring comprises a corrugated diaphragm. ### Claim 11 (depends on 1) The apparatus of claim 1, further comprising a bellows assembly, and wherein the bellows assembly comprises a sidewall for at least partially comprising the reacted mass spring. ### Claim 12 (depends on 11) The apparatus of claim 11, wherein the bellows assembly further comprises an amplifier base, and further comprising means for resiliently mounting the amplifier base relative to the outside world. ### Claim 13 A motion amplifier comprising: a piezoelectric diaphragm; a reaction mass connected to the piezoelectric diaphragm; a reacted mass connected to the piezoelectric diaphragm; a reacted mass spring for resiliently carrying the reacted mass; wherein the reacted mass spring comprises a corrugated diaphragm; wherein the reacted mass comprises a reacted mass cup which defines a reacted mass cavity, and wherein the reaction mass is suspended from the piezoelectric diaphragm in the reacted mass cavity. ### Claim 14 (depends on 13) The apparatus of claim 13, wherein the corrugated diaphragm has corrugations proximate a circumference of the diaphragm. ### Claim 15 (depends on 13) The apparatus of claim 13, wherein a periphery of the piezoelectric diaphragm is held and carried by the reacted mass. ### Claim 16 (depends on 13) The apparatus of claim 13, further comprising drive electronics for driving the piezoelectric diaphragm by generating and applying a drive signal to the piezoelectric diaphragm. ### Claim 17 (depends on 16) The apparatus of claim 16, wherein the drive electronics generates and applies a drive signal to the piezoelectric diaphragm to maintain the motion amplifier resonant at a predetermined frequency. ### Claim 18 (depends on 17) The apparatus of claim 17, wherein structure of the motion amplifier carried by the reacted mass spring has a resonant frequency f2, wherein the predetermined frequency is f2, and wherein the drive signal is generated to urge the motion amplifier to the frequency f2 as its operational frequency, thereby achieving peak amplitude displacement of the motion amplifier. ### Claim 19 (depends on 18) The apparatus of claim 18, wherein the resonant frequency f2 is related to a spring constant K2 of the reacted mass spring and a sum of masses of the reaction mass and the reacted mass. ### Claim 20 (depends on 16) The apparatus of claim 16, wherein the drive electronics generates the drive signal to maintain a predetermined phase angle between the drive signal and a signal indicative of displacement of the motion amplifier. ### Claim 21 (depends on 20) The apparatus of claim 20, wherein the drive electronics comprises a sensor for sensing displacement of the motion amplifier and for generating the signal indicative of displacement of the motion amplifier. ### Claim 22 (depends on 13) The apparatus of claim 13, further comprising: an amplifier base to which the reacted mass spring is attached; and means for resiliently mounting the amplifier base relative to the outside world. ### Claim 23 (depends on 22) The apparatus of claim 22, wherein the amplifier base carries the piezoelectric diaphragm, the reaction mass, the reacted mass, and the reacted mass spring. ### Claim 24 A motion amplifier comprising: a piezoelectric diaphragm; a reaction mass connected to the piezoelectric diaphragm; a reacted mass connected to the piezoelectric diaphragm; a reacted mass spring for resiliently carrying the reacted mass; a bellows assembly, and wherein the bellows assembly comprises a sidewall for at least partially comprising the reacted mass spring; wherein the reacted mass comprises a reacted mass cup which defines a reacted mass cavity, and wherein the reaction mass is suspended from the piezoelectric diaphragm in the reacted mass cavity. ### Claim 25 (depends on 24) The apparatus of claim 24, wherein a periphery of the piezoelectric diaphragm is held and carried by the reacted mass. ### Claim 26 (depends on 24) The apparatus of claim 24, further comprising drive electronics for driving the piezoelectric diaphragm by generating and applying a drive signal to the piezoelectric diaphragm. ### Claim 27 (depends on 26) The apparatus of claim 26, wherein the drive electronics generates and applies a drive signal to the piezoelectric diaphragm to maintain the motion amplifier resonant at a predetermined frequency. ### Claim 28 (depends on 27) The apparatus of claim 27, wherein structure of the motion amplifier carried by the reacted mass spring has a resonant frequency f2, wherein the predetermined frequency is f2, and wherein the drive signal is generated to urge the motion amplifier to the frequency f2 as its operational frequency, thereby achieving peak amplitude displacement of the motion amplifier. ### Claim 29 (depends on 28) The apparatus of claim 28, wherein the resonant frequency f2 is related to a spring constant K2 of the reacted mass spring and a sum of masses of the reaction mass and the reacted mass. ### Claim 30 (depends on 27) The apparatus of claim 27, wherein the drive electronics generates the drive signal to maintain a predetermined phase angle between the drive signal and a signal indicative of displacement of the motion amplifier. ### Claim 31 (depends on 30) The apparatus of claim 30, wherein the drive electronics comprises a sensor for sensing displacement of the motion amplifier and for generating the signal indicative of displacement of the motion amplifier. ### Claim 32 (depends on 24) The apparatus of claim 24, further comprising: an amplifier base connected to the reacted mass spring; and means for resiliently mounting the amplifier base relative to the outside world. ### Claim 33 (depends on 32) The apparatus of claim 32, wherein the amplifier base carries the piezoelectric diaphragm, the reaction mass, the reacted mass, and the reacted mass spring. ### Claim 34 A motion amplifier comprising: a piezoelectric diaphragm; a reaction mass connected to the piezoelectric diaphragm; a reacted mass connected to the piezoelectric diaphragm; a reacted mass spring for resiliently carrying the reacted mass; an amplifier base connected to at least one of the reacted mass and the reacted mass spring; means for resiliently mounting the amplifier base relative to the outside world; wherein the reacted mass comprises a reacted mass cup which defines a reacted mass cavity, and wherein the reaction mass is suspended from the piezoelectric diaphragm in the reacted mass cavity. ### Claim 35 (depends on 34) The apparatus of claim 34, wherein a periphery of the piezoelectric diaphragm is held and carried by the reacted mass. ### Claim 36 (depends on 34) The apparatus of claim 34, further comprising drive electronics for driving the piezoelectric diaphragm by generating and applying a drive signal to the piezoelectric diaphragm. ### Claim 37 (depends on 36) The apparatus of claim 36, wherein the drive electronics generates and applies a drive signal to the piezoelectric diaphragm to maintain the motion amplifier resonant at a predetermined frequency. ### Claim 38 (depends on 37) The apparatus of claim 37, wherein structure of the motion amplifier carried by the reacted mass spring has a resonant frequency f2, wherein the predetermined frequency is f2, and wherein the drive signal is generated to urge the motion amplifier to the frequency f2 as its operational frequency, thereby achieving peak amplitude displacement of the motion amplifier. ### Claim 39 (depends on 38) The apparatus of claim 38, wherein the resonant frequency f2 is related to a spring constant K2 of the reacted mass spring and a sum of masses of the reaction mass and the reacted mass. ### Claim 40 (depends on 36) The apparatus of claim 36, wherein the drive electronics generates the drive signal to maintain a predetermined phase angle between the drive signal and a signal indicative of displacement of the motion amplifier. ### Claim 41 (depends on 40) The apparatus of claim 40, wherein the drive electronics comprises a sensor for sensing displacement of the motion amplifier and for generating the signal indicative of displacement of the motion amplifier. ### Claim 42 (depends on 34) The apparatus of claim 34, wherein the amplifier base carries the piezoelectric diaphragm, the reaction mass, the reacted mass, and the reacted mass spring. ### Claim 43 (depends on 34) The apparatus of claim 34, wherein the reacted mass spring comprises a corrugated diaphragm. ### Claim 44 (depends on 34) The apparatus of claim 34, further comprising a bellows assembly, and wherein the bellows assembly comprises a sidewall for at least partially comprising the reacted mass spring.