TRANSDUCER FOR ULTRASONIC MACHINE TOOL

• US 3,619,671 A
• Filed: 12/29/1969
• Issued: 11/09/1971
• Est. Priority Date: 12/29/1969
• Status: Expired due to Term

• Current Assignee: Andrew Shoh
• Original Assignee: Andrew Shoh
• Inventors: Shoh, Andrew
• Primary Examiner(s): Hirshfield, Milton O.
• Assistant Examiner(s): Budd, Mark O.
• Application Number:
  US04/888,468
• Time in Patent Office: 680 Days
• Field of Search: 51/59,59SS,34,34.7,56,DIG.11 77/5,5CB 310/8.2,8.3,8.7,26 173/97,100,104
• US Class Current: 310/325
• CPC Class Codes: B06B 1/06 operating with piezoelectric effect or with electrostriction piezoelectric or electrostrictive devices per se H10N30/00
• CPC Class Codes: Y10T 408/23 including means to cause Tool to progressively vibrate toward work

Abstract

An ultrasonic transducer for machine tool purposes comprises two elongated coaxially disposed members coupled to each other with one of the members being adapted to oscillate as a halfwavelength resonator at the predetermined frequency, typically 20 kHz. The transducer is designed to be coupled to a drill of conventional design and when so coupled causes a tool bit to rotate while undergoing axial oscillation at the predetermined frequency.

Claims

1. A coaxial electromechanical transducer assembly comprising:

a first elongate member;

a second elongate member surrounding, at least partially, said first member and being radially spaced from said first member;

electroacoustic means coupled to one of said members for causing, responsive to the energization of said electroacoustic means with an electrical signal of predetermined frequency, said one member to undergo axial vibrations and be resonant, whereby said one member exhibits antinodal regions of axial vibration spaced apart by one-half wavelength of the vibrations, and diaphragm support means adapted to flex disposed at least at two of said antinodal regions for coupling said members to each other in spatial relationship and for restricting relative movement between said members to motion along the axial direction, and said respective diaphragm support means causing the axial forces transmitted therethrough to be in opposition.

2. A coaxial electromechanical transducer assembly as set forth in claim 1, said diaphragm support means being spaced-apart substantially one-half wavelength of the vibration of said one member.

3. A coaxial electromechanical transducer assembly as set forth in claim 1, said diaphragm support means having the shape of radial flanges, each flange extending from one of the members to the other member, and means for fastening said members to one another at said flanges.

4. A coaxial electromechanical transducer assembly as set forth in claim 3, and means disposed at one end of said one member for receiving a tool adapted to operate on a workpiece.

5. A coaxial electromechanical assembly as set forth in claim 4, and said one member being dimensioned to be resonant at an ultrasonic frequency.

6. An electromechanical transducer assembly as set forth in claim 5, and means coupled for imparting rotation to one of said members for rotating said assembly about its axis.

7. An electromechanical transducer assembly comprising:

a shaft;

a sleeve concentric with said shaft and radially spaced therefrom;

said sleeve being dimensioned to undergo axial vibrations and be resonant as a half-wavelength resonator at the frequency of sound traveling longitudinally through said sleeve, said sleeve when resonant exhibiting a pair of antinodal regions of longitudinal motion;

electroacoustic means adapted to be excited with electrical energy of predetermined frequency coupled to said sleeve for causing said sleeve to be resonant;

a radial flange adapted to undergo flexural motion disposed at each of said antinodal regions and coupling said shaft to said sleeve whereby to support said sleeve about said shaft and said flanges restricting movement of said sleeve when resonant to motion principally along the longitudinal axis;

means coupled for imparting rotating motion to said shaft;

tool-receiving means disposed on said sleeve for causing a tool coupled to said receiving means to be responsive to the rotating motion imparted to said shaft and to the vibratory motion of said sleeve, and an electrical slip ring assembly coupled mechanically to said shaft and electrically coupled to said electroacoustic means for providing electrical excitation to said electroacoustic means when said transducer is rotating.

8. An electromechanical transducer assembly as set forth in claim 7, said electroacoustic means comprising a set of piezoelectric disks, and including clamping means for holding said disks under compression and coupling said disks to said sleeve.

9. An electromechanical transducer as set forth in claim 8 and means for securing said shaft and sleeve in fixed angular relationship for causing positive transfer of rotational torque and axial thrust from said shaft to said sleeve.

10. An electromechanical transducer as set forth in claim 9, said means securing said shaft and sleeve in fixed angular relationship comprising radially placed means disposed substantially in a noDal region of said sleeve and extending from said sleeve into said shaft.

11. An electromechanical transducer assembly as set forth in claim 7, one of said radial flanges being integral with said sleeve and the other radial flange being integral with said shaft.

12. A coaxial electromechanical transducer assembly comprising:

a first elongate member;

a second elongate member surrounding, at least partially, said first member and being radially spaced from said first member;

electroacoustic means coupled to one of said members for causing, responsive to the energization of said electroacoustic means with an electrical signal of predetermined frequency, said one member to undergo axial vibrations and be resonant, whereby said one member exhibits antinodal regions of axial vibration spaced apart by one-half wavelength of the vibrations;

metallic support means adapted to flex disposed at two of said antinodal regions for locating and coupling said members in spatial relationship to each other, and said support means being of a configuration to restrict relative movement between said members to motion principally to that along the axis of said assembly, and means coupled to one of said members for imparting rotation thereto whereby to rotate said assembly.

13. A coaxial electromechanical transducer assembly as set forth in claim 12, said support means comprising flange shaped means.

14. A coaxial electromechanical transducer assembly as set forth in claim 12, said support means comprising diaphragm means.

15. A coaxial electromechanical transducer assembly as set forth in claim 14, said diaphragm means being disposed at two proximate antinodal regions.

16. A coaxial electromechanical transducer assembly comprising:

a first elongate member;

a second elongate member surrounding, at least partially, said first member and being radially spaced from said first member;

piezoelectric transducer means coupled to one of said members for causing, responsive to the energization of said piezoelectric transducer means with an electrical signal of predetermined frequency, said one member to undergo axial vibrations and be resonant, whereby said one member exhibits antinodal regions of axial vibration spaced apart by one-half wavelength of the vibrations;

diaphragm support means adapted to flex disposed at least at two of said antinodal regions for coupling said members to each other in spatial relationship and for restricting relative movement between said members to motion along the axial direction, and said respective diaphragm support means causing the axial forces transmitted therethrough to be in opposition, a pair of electrically conductive slip rings mounted to said assembly and electrically connected to said piezoelectric means, and means locking said elongate members to each other in angular relation to ensure positive transmission of rotational force between said members.