Piezoelectric Electric Energy Generating Device

Abstract

An electrical current generating device having a sound wave force magnifying structure in the form of a force transmission pin which is longitudinally slidable within a body bore and having a proximal end of a large area for receiving sound wave forces, and having a greatly reduced area distal end which bears on a piezoelectric element.

Claims

1. An electrical current generating device comprising a body with a top end surface and a bottom end surface, a shaft bore formed around a longitudinal axis of said body and extending through said end surfaces, said end surfaces lying in parallel planes which are perpendicular to said axis, said top end surface being formed with a rim wall centered around said axis and extending substantially axially therefrom, wherein said rim wall has a distal top surface lying in a plane parallel to said planes of said end surfaces, a holder affixed to said body against said bottom end surface and having a wall portion defining a cavity facing said bottom end surface, a piezoelectric element affixed in said cavity and having a pressure receiving portion exposed to said bore, a vibration pin having a shaft portion slidably mounted in said bore and having a distal end lightly engaging said pressure receiving portion of said piezoelectric element, said shaft portion further having a disc shaped head having a planar pressure face and being formed on a proximal end of said shaft portion, wherein said pressure face is spaced above said distal top surface of said rim wall, a flexible membrane affixed to said body and overlying said pressure face and said distal top surface, a generally conically shaped funnel structure affixed to said upper end portion of said body for funneling energy waves onto said membrane, and positive and negative wiring affixed to said piezoelectric element and extending out of said cavity thru a channel formed through said wall portion of said holder.

2. The device of claim 1 wherein said vibration pin is comprised of lightweight plastic material.

3. The device of claim 2 wherein the ratio of the horizontal area of said pressure face to the area of said distal end of said shaft portion of said pressure pin is from about 2/1 to about 20/1.

4. The device of claim 1 wherein said piezoelectric element is composed of brass.

5. The device of claim 1 wherein said pressure face of said head is spaced above said distal of said rim wall a distance of from about 0.001 in. to about 0.008 in.

6. The device of claim 2 wherein said plastic material is polylactic acid polymer.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0017] The present invention is further explained by the drawings herein wherein the various figures are not drawn to scale or in consistent structural proportions, wherein:

[0018] FIG. 1 is a cone end perspective view of the present electricity generating device wherein the sound responsive membrane and the pressure pin are in their neutral positions;

[0019] FIG. 2 is a piezoelectric element end perspective view of the present electricity generating device;

[0020] FIG. 3 is a view as in FIG. 2 with the housing removed;

[0021] FIG. 3A is a side view of the isolated cone, vibration pin and piezoelectric element components of the present device;

[0022] FIG. 4 is a cross-sectional view taken along line 4-4 in FIG. 1;

[0023] FIGS. 4A, 4B and 4C are taken from the dotted encircled areas of FIG. 4;

[0024] FIG. 5 is a cross-sectional view taken along line 5-5 in FIG. 4;

[0025] FIG. 6 is a cross-sectional view taken along line 6-6 in FIG. 4;

[0026] FIG. 6A is a cross-sectional view taken along line 13-13 in FIG. 6;

[0027] FIG. 7 is a cross-sectional view taken along line 7-7 in FIG. 5;

[0028] FIG. 8 is a cross-sectional view without the piezo element housing;

[0029] FIG. 9 is a cross-sectional view as in FIG. 8 showing typical dimensions given in inches; and

[0030] FIG. 10 is an exploded explanatory assembly view of the basic components of the present device.

DETAILED DESCRIPTION OF THE DRAWINGS

[0031] As shown in the drawings, the basic structure of the present device comprises a generally cone shaped sound wave cylindrical funneling structure 16, which from the constricted end 18 thereof depends a cylindrical mounting sleeve 20 which is slidable over but frictionally secured to a circular peripheral rim portion 22 of a flexible membrane 24 by being tightly sandwiched against a circular surface 26 of body member 28. This tightening structure preferably comprises a gap 60 vertically formed in sleeve 20 and tabs 56 molded to sleeve 20 and provided with bolt 58 which when tightened draws the gapped sleeve tightly around membrane rim 22 and surface 26 of body member 28.

[0032] A piezoelectric element 30 is affixed in and to a holder 32 at the base 36 of the holder. The holder is secured to a body member 28 by screws 29. The piezoelectric element may consist of any of a wide variety of materials that are responsive to pressure for generating electrical current and include, for example quartz, brass, zirconate compounds, titanium, Pb zirconate, Ca titanate, and is provided with 38 and 40 terminals wherein their lead conductors 42 and 44 respectively extend from the terminals to the exterior of the holder 32 through a channel such as 46 formed in a wall 47 of said holder.

[0033] A vibration pin 48, preferably of lightweight material, preferably plastic, is slidably mounted in bore 50 with clearance sufficient to offer negligible resistance to its axial reciprocation within said bore. It is particularly noted the head area 52 of the pin is markedly enlarged relative to the distal end area 54 of the pin, thereby magnifying the pressure which the sound waves exert upon the piezoelectric element. A ratio of about 2/1 to about 20/1 of the pin head area to the distal end area of the pin is preferred for the smaller devices. Most preferably the top surface of the pin head is slightly e.g., 0.001-0.008 in. above the top circular surface 33 of top body rim 34.

[0034] Membrane 24 is comprised of any of a wide variety of highly flexible materials such as natural or synthetic rubbers or synthetic elastomers, whereby very light sound wave forces can cause the circumferential flex area 58 of the membrane to deform and bring the membrane into forcible contact with head 52 of said pin.

[0035] A preferred, but not limited to, list of component materials is as follows: [0036] “Sound Collection “Cone” (16)—polylactic acid or polylactide (PLA) which is a biodegradable and bioactive thermoplastic aliphatic polyester; [0037] “Membrane” (24)—0.8 MM thick Polyurethane; [0038] “Vibration Pin” (48)—PLA (Poly Lactic Acid); [0039] “Piezoelectric Element” (30)—0.5 MM thick by 32 MM Diameter C23000 Brass which is an alpha brass having only one phase crystalline structure. This crystalline structure is “Face Centered Cubic Crystal Structure” on the molecular level; [0040] “Housing” or “Body Member” (28) and “Holder” (32)—Acetal copolymers having high tensile and flexural strength, fatigue resistance, hardness and excellent lubricity is excellent. These plastics retain much of their toughness through a broad temperature range and are among the most creep resistant of the thermoplastics.