Percussion transducer

• US 4,984,498 A
• Filed: 09/06/1989
• Issued: 01/15/1991
• Est. Priority Date: 10/26/1987
• Status: Expired due to Fees

• Current Assignee: Fishman Transducers Incorporated
• Original Assignee: Lawrence R. Fishman
• Inventors: Fishman, Lawrence
• Primary Examiner(s): Grimley, A. T.
• Assistant Examiner(s): Smith, Matthew S.
• Application Number:
  US07/403,378
• Time in Patent Office: 496 Days
• Field of Search: 84/723, 84/730, 84/732, 84/743, 84/402, 84/DIG. 24, 84/DIG. 12, 29/594, 29/25.35, 381/114, 310/324, 310/328, 310/329, 310/339
• US Class Current: 84/730
• CPC Class Codes: G10D 13/02 Drums; Tambourines with drumheads
• CPC Class Codes: G10D 13/26 Mechanical details of electronic drums
• CPC Class Codes: G10H 2220/525 Piezoelectric transducers for vibration sensing or vibration excitation in the audio range; Piezoelectric strain sensing, e.g. as key velocity sensor; Piezoelectric actuators, e.g. key actuation in response to a control voltage
• CPC Class Codes: G10H 2230/275 Spint drum
• CPC Class Codes: G10H 3/146 using a membrane, e.g. a drum; Pick-up means for vibrating surfaces, e.g. housing of an instrument
• CPC Class Codes: Y10S 84/12 Side; rhythm and percussion devices
• CPC Class Codes: Y10S 84/24 Piezoelectrical transducers
• CPC Class Codes: Y10T 29/49005 Acoustic transducer

Abstract

A percussion instrument transducer for converting a striking impact into a representative electrical impulse triggering signal. The transducer is formed of a piezoelectric member of disc shape secured to an electrically conductive disc. The piezoelectric member and disc are supported in a housing on a support platform of smaller diameter than the diameter of the disc so that the periphery of the disc is cantilevered beyond the support platform to provide enhanced piezoelectric impulse action.

Claims

1. In combination, a percussion transducer for a musical percussion instrument, said transducer for mounting on the said instrument and for converting a striking impact into a representative electrical impulse triggering signal, said transducer comprising:

a piezoelectric disc having oppositely disposed electrodes on either side thereof including top and bottom electrodes,

an electrically conductive disc,

means fixedly supporting said bottom electrode of said piezoelectric disc to an upper surface of said conductive disc,

a housing having an interior chamber in which is disposed said piezoelectric disc and conductive disc,

said housing including a bottom wall having a support platform for supporting said conductive disc at a lower surface thereof,

said housing further having a peripheral side wall defining a diameter of the housing that is greater than the diameter of the conductive disc and greater than the height of the housing,

said support platform being of smaller dimension than said conductive disc so that the periphery of said conductive disc is cantilevered beyond said support platform to provide enhanced piezoelectric impulse action,

lead means coupling to at least said piezoelectric disc for deriving a signal therefrom,

adhesive means for resiliently securing the conductive disc at its lower surface to the top surface of said support platform,

and means for securing the transducer to the instrument.

2. A percussion transducer as set forth in claim 1 wherein said adhesive means comprises a silicone RTV adhesive.

3. A percussion transducer as set forth in claim 1 wherein the support platform has a diameter D1 and the conductive disc has a diameter D2, and wherein the diameter D1 is in a range on the order of 25% to 75% of the diameter D2.

4. A percussion transducer as set forth in claim 1 wherein said piezoelectric disc and said conductive disc are both relatively thin having a thickness at least an order of magnitude less than the height of the housing.

5. A percussion transducer as set forth in claim 1 wherein the electrodes are silver electrodes.

6. A percussion transducer as set forth in claim 1 wherein the means for fixedly supporting the piezoelectric disc to the conductive disc comprises a conductive adhesive.

7. A percussion transducer as set forth in claim 6 wherein said conductive adhesive comprises a conductive epoxy.

8. A percussion transducer as set forth in claim 1 wherein said conductive disc comprises a thin beryllium disc.

9. A percussion transducer as set forth in claim 1 wherein said conductive disc comprises a thin brass disc.

10. A percussion tranducer as set forth in claim 1 wherein said housing further comprises a cover for completely enclosing the piezoelectric disc and conductive disc.

11. A percussion transducer as set forth in claim 1 wherein said lead means has two wires, one secured to the piezoelectric disc and the other to said conductive disc.

12. A percussion transducer as set forth in claim 1 wherein said lead means includes one lead secured to said top electrode of the piezoelectric disc and another lead secured to the conductive disc.

13. A percussion transducer as set forth in claim 12 wherein the piezoelectric disc is of smaller diameter than the diameter of the conductive disc with the other lead secured to the exposed top edge area of the conductive disc.

14. A percussion transducer as set forth in claim 13 wherein said housing has a hole in the peripheral side wall thereof to receive said lead means.

15. A percussion transducer as set forth in claim 14 including an eyelet in said hole encrimped to secure said lead means.

16. A method of fabricating a percussion transducer for mounting on a percussion instrument and for converting a striking impact into a representative electrical impulse triggering signal, said method comprising the steps, providing a piezoelectric member, providing an electrically conductive disc means, securing the piezoelectric member and disc means together to form a unitary element, providing a housing having a diameter greater than its height and defining an interior chamber and a support platform, resiliently adhesively supporting said unitary element on the support platform and providing lead means coupling to at least said piezoelectric member for deriving a signal therefrom.

17. A method as set forth in claim 16 including further providing the support platform of smaller dimension then the disc means so that the periphery of the disc means is cantilevered beyond the support platform to provide enhanced piezoelectric impulse action.

18. A method as set forth in claim 17 wherein the support platform has a diameter D1 and the disc means has a diameter D2, and wherein the diameter D1 is in a range on the order of 25%-75% of the diameter D2.

19. A percussion transducer for mounting upon a percussion instrument, said transducer for converting a striking impact into a representative electrical impulse triggering signal, said transducer comprising;

a piezoelectric disc having oppositely disposed electrodes on either side thereof, an electrically conductive disc, means fixedly supporting one electrode of said piezoelectric disc to an upper surface of said conductive disc, a housing for receiving said piezoelectric disc and said conductive disc, said housing including a bottom wall having a support platform for supporting said conductive disc at a lower surface thereof, adhesive means for resiliently securing the conductive disc at its lower surface to the top surface of said support platform, lead means coupled to at least said piezoelectric disc for deriving a signal therefrom, said adhesive means defining the only means for holding the conductive disc to the support platform, an unfilled air space being provided over the piezoelectric disc with an absence of contact of any retaining means to cover the piezoelectric disc except for the lead means, and means disposed over the top surface of said piezoelectric disc forming a resilient dampening layer that extends to cover at least the portion of the piezoelectric disc that overlies the support platform.

20. A percussion transducer as set forth in claim 19 wherein said housing further has a peripheral side wall defining a diameter of the housing that is greater than the diameter of the conductive disc and greater than the height of the housing.

21. A percussion transducer as set forth in claim 19 wherein said adhesive means comprises a resilient adhesive that has some pliability thereto even in the cured state of said adhesive means.

22. A percussion transducer as set forth in claim 21 wherein said adhesive means comprises a silicone RTV adhesive.

23. A percussion transducer as set forth in claim 21 wherein the support platform has a diameter D1 and the conductive disc has a diameter D2, and wherein the diameter D1 is in a range on the order of 25% to 75% of the diameter D2.

24. A percussion transducer as set forth in claim 19 wherein said means forming a resilient dampening layer comprises an adhesive layer that is pliable even when cured.

25. A percussion transducer as set forth in claim 24 wherein the resilient dampening layer extends to cover the entire piezoelectric disc.

26. A percussion transducer as set forth in claim 25 wherein the periphery of the resilient layer extends to a point intermediate of the peripheral edges of the respective piezoelectric and electrically conductive discs.