Ultrasonic method and actuator for inducing motion of an object

• US 6,362,557 B1
• Filed: 08/28/2000
• Issued: 03/26/2002
• Est. Priority Date: 08/28/2000
• Status: Expired due to Term

• Current Assignee: X Corp. (f/k/a Twitter, Inc.) (X Holdings Corp.)
• Original Assignee: International Business Machines Corporation
• Inventors: Gruber, Peter A., Walker, George F., Maurer, Frederic
• Primary Examiner(s): BUDD, MARK OSBORNE
• Application Number:
  US09/649,486
• Time in Patent Office: 575 Days
• Field of Search: 310/323.02, 310/323.06, 310/323.12, 310/328
• US Class Current: 310/323.02
• CPC Class Codes: H02N 2/002 using only longitudinal or radial modes
• CPC Class Codes: H02N 2/0095 producing combined linear and rotary motion, e.g. multi-direction positioners
• CPC Class Codes: H02N 2/026 by pressing one or more vibrators against the driven body
• CPC Class Codes: H02N 2/028 along multiple or arbitrary translation directions, e.g. XYZ stages
• CPC Class Codes: H02N 2/10 producing rotary motion, e.g. rotary motors
• CPC Class Codes: H02N 2/103 by pressing one or more vibrators against the rotor
• CPC Class Codes: H10N 30/202 using longitudinal or thickness displacement combined with bending, shear or torsion displacement

Abstract

An actuator scaled to macroscopic or microscopic sizes, uses ultrasonic energy to induce motion of an object in a desired direction. The actuator includes one or more pair of piezoelectric transducers connected with a transducer tip. Supplying the piezoelectric transducers with alternating current electrical power causes the tip to vibrate at ultrasonic frequencies. Urging the vibrating tip into contact with a surface on the object at a selected angle of inclination induces the object to move in the desired direction at a rate determined by the inclination angle. Multiple actuators can be used to induce a fall range of movements of variously shaped objects. In microscopic form, the actuator can be used to create a MEMS device. The optional application of a compliant material either on the transducer tip or on the object'"'"'s surface enhances the movement induced by the actuator.

Claims

1. An actuator for producing tilting movement of a rigid body about a fulcrum, comprising:

a piezoelectric device contacting one end of said body, said piezoelectric device being longitudinally extendable in response to the application thereto of electrical power, the extension of said device imposing a moment on said body causing said body to tilt about said fulcrum; and

an ultrasonic transducer generating longitudinal vibratory movement in response to the application thereto of alternating current electrical power, said transducer including a transducer tip contacting and imposing a force on said body, said transducer tip force holding said body on said fulcrum during tilting of said body.

2. The actuator of claim 1, wherein said ultrasonic transducer includes at least 2 piezoelectric crystals arranged to generate said longitudinal vibratory movement.

3. The ultrasonic actuator of claim 1, wherein each of said device and said transducer has a length between 0.01 and 1 inch.

4. The ultrasonic actuator of claim 1, wherein each of said device and said transducer has a length of between 1 and 10 inch.

5. The actuator of claim 1, wherein said transducer includes a cylindrical housing, said crystals are restrained for longitudinal expansion and contraction within said housing, and said tip is disposed on one end of said housing.

6. The actuator of claim 1, wherein said tip includes a coating of compliant material thereon.

7. The actuator of claim 6, wherein said compliant material is a cured polyamide.

8. The actuator of claim 6, wherein said compliant material is rubber.