Electronic Sensor Device for Detecting the Vibration Related to an Amplification System within Stringed Musical Instruments

Abstract

An electronic sensor device for detecting the vibration related to an amplification system within stringed musical instruments. The described structure is detachably mounted below the saddle. It comprises several central piezoelectric elements, several metal capped poles, and each metal capped pole consists of an integrally formed pole and cap, from top to bottom.

The top end of the pole extends through a matching positioning hole into the saddle slot and touches the bottom of the saddle. The bottom end of the cap accurately captures the top of the central piezoelectric element, and the top ring of the cap is closely pressed up to the bridge plate.

The invention provides an electronic sensor device for detecting the vibration related to an amplification system within stringed musical instruments, which is easy to install and is easily uninstalled. By applying mass on the non-sensing side of piezoelectric element assembly, the electro-acoustic amplification performance of the instruments is greatly enhanced, as it is firmly coupled to the stringed instruments, therefore improving the sensing efficiency, in providing better output and tone that is closer to the original acoustic

Claims

1. An electronic sensor device for detecting the vibration related to an amplification system within stringed musical instruments of the type which include a saddle mounted into a saddle slot of a bridge which is mounted onto the outside of a sound board; one end of a string of a musical instrument is stretched over a saddle; on the inside of a sound board, is a bridge reinforcing plate, such that a bridge reinforcing plate is immediately under the bridge separated by the sound board; a pickup assembly is detachably mounted on the inside of a sound board and partially extends upwardly to a bottom of a saddle, the sensor device is comprised of; a) a fixed and mounted piezoelectric element for each string, which is configured to convert string vibrations into electrical signals, each piezoelectric element is connected to a metal capped rod, wherein from top to bottom each integrally formed metal capped rod includes a rod portion with a top, and a cap portion with a top annular shoulder, and a bottom piezo receiving cavity, for each piezo-electric element the piezo receiving cavity is adapted to receive in abutting fashion the top of the piezoelectric element, b) the top of the rod portion is well coupled in abutting relationship with a bottom of the saddle below a saddle slot, and the top annular shoulder of the cap portion is located in well coupled abutting relationship with a bridge reinforcing plate, such that induced vibration from a string is transmitted through a sound board through the bridge reinforcing plate and onto the top annular shoulder of the metal capped rod, and vibration from a string is also transmitted through the saddle to the top of the metal capped rod wherein the metal capped rod transmits and carries vibrations from the saddle and also from the sound board via the bridge reinforcing plate to the piezo electric element.

2. The electronic sensor device claimed in claim 1 further includes; a pickup base fixing assembly positioned under the bridge reinforcing plate, the pick-up base fixing assembly includes a pick up base which is connected to the non-sensing side of the piezoelectric elements, and is detachably rigidly fastened to the bridge, the pickup base is adapted to provide a pre-selected amount of mass to the pickup assembly, wherein the upper surface of the pickup base presses against the bottom ends of the piezoelectric elements, so that each metal capped rod is equally pressed up in intimate well coupled contact with the saddle and the bridge reinforcing plate, thereby creating a well coupled acoustic structure.

3. The electronic sensor device claimed in claim 2 further includes; a number of auxiliary piezoelectric elements positioned in parallel and closely to the metal capped rods, to sense the vibration proximate the centre of the soundboard, the auxiliary piezoelectric elements are distributed on the upper surface of the pickup base on either sides of the centrally located piezoelectric elements, and the top of each auxiliary piezoelectric element is fitted with a metal cap which abut against the bridge reinforcing plate, for operably transmitting a string vibration to the piezo electric element.

4. The electronic sensor device claimed in claim 1 further includes an adjustable contact area between the top annular shoulder and the bridge reinforcing plate by selecting the diameter of the top annular shoulder, wherein the diameter of the positioning hole is less than or equal to the width of the saddle slot.

5. The electronic sensor device claimed in claim 4 further wherein the diameter of the positioning hole does not exceed the width of the saddle slot, and the described installation nuts and bolts are dimensioned according to the size of the positioning hole.

6. The electronic sensor device claimed in claim 4 wherein the pick-up base is installed with nuts and bolts which pass through the bridge reinforcing plate, the soundboard and bridge at either ends of the saddle slot and the top of the bolts are T shaped or inverted L shaped, to nest within the saddle slot and to avoid contact with the saddle.

7. The electronic sensor device claimed in claim 4 further includes; wherein the pickup base surface which is connected to the non-sensing side of the piezoelectric element comprises a flat surface and the pick-up base is made of non-magnetic metal.

8. The electronic sensor device claimed in claim 4 further wherein the pickup base is also equipped with an electromagnetic shielding layer for shielding against radio frequency.

9. The electronic sensor device claimed in claims 1 and 5 further wherein the musical stringed instrument is a guitar, and the number of strings and therefore the number of metal capped rods and piezoelectric elements are selected between 4 and 12.

10. The electronic sensor device claimed in claim 3 wherein the number of auxiliary piezoelectric elements is selected from 2 to 12.

11. The electronic sensor device claimed in claim 3 wherein each piezo-electric element is cylindrical and the piezo receiving cavity includes a partially cylindrical portion adapted to receive, in piston and cylinder fashion, the piston shaped top of the piezoelectric element.

12. The electronic sensor device claimed in claim 2 wherein the pickup assembly includes an internal electrical contact and an insulator strip positioned between the bottom of the piezo electric element and the top of the pick-up base.

Description

DESCRIPTION OF DRAWINGS

[0038] FIG. 1 is a schematic diagram of the assembly structure of the invention.

[0039] FIG. 2 is a schematic diagram of the exploded view of structure of the invention.

[0040] FIG. 3 is a top view of the installation of the invention in the bridge.

[0041] FIG. 4 is a side view of the assembly structure of the invention.

[0042] FIG. 5 is a schematic diagram of the structure of this invention mounted on the underside of the soundboard.

[0043] FIG. 6 is a schematic diagram of the assembled view of the metal capped rods and the central piezoelectric elements of this invention mounted together.

[0044] FIG. 7 is a schematic diagram of case 2 of this invention.

[0045] FIG. 8 is a schematic cross sectional view of the pick-up assembly of one piezo electric element and includes a saddle, metal capped rods, bridge, sound board, bridge reinforcing plate, piezo electric element, electrical contact, insulator strip, piezo receiving cavity, saddle slot and pick up base.

SPECIFIC IMPLEMENTATION METHODS

[0046] This invention is further illustrated in conjunction with the illustration of the drawings and the implementation case.

[0047] Case 1: Refer to FIGS. 1 to 6. An electronic sensor device for detecting the vibration related to an amplification system within stringed musical instruments. The described stringed instrument is a guitar.

[0048] The front of the soundboard 7 of the stringed instrument is equipped with a bridge 1, and the back of the soundboard usually comprises a bridge reinforcing plate 10. The described bridge is equipped with string positioning holes 4 and a saddle slot 3 for installing the saddle 2. The strings pass through the string pin holes from outside and are pinned or affixed to the bridge reinforcement plate.

[0049] Steel string guitar strings produce approx 70 kg of tension at standard pitch or tuning, and nylon string guitar strings usually produce 40 kg of tension. In addition, there are also bracings on the back of the face panel, protecting the face from cracking and deforming under the tension of the strings.

[0050] The described electric pickup device is detachably mounted below the saddle 2, it comprises:

[0051] Several centrally located piezoelectric elements, 5, to convert vibration into electrical signals.

[0052] A number of metal capped rods 6 for mounting on the tops of the centrally located piezoelectric elements and transmitting the induced vibration to the fixed centrally located piezoelectric elements, in which the number of the metal capped rods and the central piezoelectric elements are six.

[0053] The described metal capped rod 6 from top to bottom consists of an integrally formed rod portion 61 and a cap portion 62. The top 54 of the rod portion 61 extends through a matching positioning hole 60 to the saddle slot 3, and touches the bottom of the saddle 2.

[0054] Referring to FIG. 8 which is a schematic cross sectional view of a portion of the pick-up assembly taken through one piezo-electric element and includes saddle 2, metal capped rod 6, bridge 1, sound board 7, bridge reinforcing plate 10, piezo electric element 5, and pick up base 8. It further depicts top 54 of rod portion 61 also referred to as rod, top annular shoulder 52 of cap portion 62 also referred to as cap, electrical contact 91 which is normally positive, insulator strip 93, piezo receiving cavity 68, saddle slot 95 and electromagnetic shielding 78.

[0055] The bottom of the cap 62 accurately captures the top of the central piezoelectric element, and the top annular shoulder 52 of the cap 62 is pressed up against the bridge reinforcing plate. The vibration of the soundboard is picked up by the caps through the bridge reinforcing plate. The bridge reinforcing plate is an important aspect of the soundboard. The sensing and reproduction of the vibration at the soundboard's central contributes to quality and realism of the amplified performance of the stringed musical instrument. Therefore, this invention provides a more realistic reproduction of the performance of an acoustic guitar, as the metal capped rods are well coupled to the piezoelectric elements and the soundboard producing a well coupled acoustic structure. A well coupled acoustic structure is one in which the elements of the structure are in intimate contact to promote transmission and carrying of acoustic vibrations. The described rod aspect passes through a positioning hole comprising a diameter of 3 mm; or a similar suitable size.

[0056] The soundboard of a stringed instrument vibrates sympathetically with the strings when they are played or plucked, and therefore the soundboard is an acoustic amplifier.

[0057] A pickup device senses the soundboard and the guitar body's resonance, creating a proportionate electrical signal, which is then amplified.

[0058] In this invention, the metal capped rods are firmly coupled with the piezoelectric elements as well as to the soundboard, so that they sense the string vibration under saddle and vibration at the soundboard's centre then transmit it to the coupled piezoelectric elements, providing a more realistic reproduction of the original performance of the guitar.

[0059] The described device also comprises a pickup base 8 for the central piezoelectric elements to sit on. The purpose of this base is for applying mass on the non-sensing side of the central piezoelectric elements and for fixing the device under the bridge within the stringed instrument; the upper surface of the pickup base is clamped by means of nuts and bolts at either end of the structure: to the base comprising piezoelectric elements, and device also comprises an internal, and so shielded circuit. It is installed with bolts 80 and nuts 81 through the bridge reinforcing plate, the soundboard, and the saddle slot on either ends of the saddle.

[0060] In order to apply a greater mass on the non-sensing side of the piezoelectric elements, that is, the side that does not directly contact the stringed instrument, the pickup base is made of relatively dense and stiff metal or alloy. The piezoelectric elements themselves are of a greater mass and volume than strip type piezo element sensors, which means the aspect that does not directly contact the stringed instrument comprises greater mass, the piezoelectric effect is enhanced, that is, that it produces greater electrical output than the referred to prior art. The piezoelectric elements are also well coupled to the stringed instrument, which reduces the possibility of feedback, extraneous vibration and improves efficiency.

[0061] The described pickup circuit is used to connect the piezoelectric elements, outputting the sensed signals from the piezoelectric elements by means of an electrical lead. The described electrical lead enables the device to be connected to an electrical preamplifier. In the current permutation the invention only has one output lead connecting it to an electrical preamplifier.

[0062] The diameter of the currently described positioning hole 60 is less than or equal to the width of the saddle slot. The width of the standard prior art saddle slot in the West is 3.2 mm, but in China are generally 3 mm, 2.8 mm and 2.5 mm. In this case, according to the different width of the saddle slot of stringed instruments, the diameter of the positioning hole 60 is 1 mm to 3.2 mm.

[0063] The diameter of the currently described positioning hole is not more than 3 mm, and the installation bolts and nuts are equivalent 3 mm bolts and nuts. This invention can be clamped or well coupled under the soundboard. The installation bolts are tightened from inside the instrument, which affects neither the structure nor the appearance of the guitar, and is far superior to the existing technology in which the installation requisites negatively affect the structure of the guitar and its appearance.

[0064] The heads of the described bolts for installation is T-shaped or inverted L-shaped, to suit the width of the saddle slot, so that once the installation is completed, the entire assembly is invisible, being covered by the saddle. Compared with the third method of the prior art, this invention achieves more solid coupling, because in the third method of the prior art, the bolts lock the screw holes at the two ends of the aluminum base from the two ends of the saddle slot downwards, and relies on the tapping of the threads into the aluminum base for the tightness; while the bolts with T-type or L-type screw heads are locked at the two ends of the saddle slot.

[0065] In this invention there are two nuts under the screw holes on both ends of the aluminum base to secure the structure, which greatly improves the efficiency of coupling, enhancing sound transmission so increasing the sensitivity and reproduction of the instrument's acoustic performance.

[0066] The described pickup base 8 is extruded or machined aluminum or brass comprising a flat surface thus avoiding the common problem of uneven contact related to the strip piezoelectric systems in the prior art. Simultaneously, the extruded or machined aluminum or brass section is a metal material which is relatively hard so comprising sufficient mass to optimize the device's performance.

[0067] The described pickup base comprises an electrical radio frequency shielding layer. That is, the pickup base comprises a solid aluminum bar and a plastic shell coated with shielding paint on the outer surface. The outer surface of the plastic shell as well as the outer surface of the piezoelectric elements form the assembly, and are sprayed with copper or other shielding paint to form the electrical shielding layer.

[0068] The contact area between the top annular shoulder 52 of the described cap 62 and the back of the sound board is adjustable, and by adjusting the contact area, adjustable is the balance of the amount of soundboard vibration picked up by the cap, and the amount of string vibration picked up from the saddle by the top of the rod.

Compared with the Third Method of Prior Art, the Invention has Three Differences:

[0069] 1) The third method of prior art requires pre machined holes or routings of the instrument's bridge, the soundboard and the bridge reinforcing plate, compromising the instrument's original structure: That is, several approx. 5 mm diameter holes to accommodate the piezoelectric cylindrical prisms, which will affect the manner in which the device is coupled as well as the structure of the instrument. In other words the prior art devices do not use metal capped rods 6. By contrast, this invention requires the drilling of small holes to accommodate the metallic capped rods comprising a diameter of less than 3 mm;

[0070] 2) The third method of prior art requires the holes pre-drilled or milled in the process of guitar making, in anticipating installation of the pickup systems, and it requires the bridge reinforcing plate to comprise a pre-routed aperture to allow the piezoelectric cylindrical prisms assembly to pass through the bridge reinforcing plate 10. As otherwise the assembly will not couple with the saddle's base in which case it would be ineffective.

[0071] 3) Whereas in the invention, the length of piezoelectric cylindrical prisms is effectively increased by the use of caps and integral rods. As well, in the invention the vibration of the wood, besides the vibration of the strings, can also be sensed, improving the device's performance.

[0072] Case 2: Refer to FIG. 7. The difference between case 2 and case 1 is that besides six central piezoelectric elements, the sensing structure also includes two to eight auxiliary piezoelectric elements 9, which are used to sense the vibration of the center of the soundboard. The number and location of the auxiliary piezoelectric elements depends on the practical application requirements. In this case, the conductive structure includes four. The auxiliary piezoelectric elements are distributed on the upper surface of the pickup base on either sides of the central piezoelectric element, and metal caps 91 for transmitting face panel vibration are fitted on top of the piezo seamlessly. The top of the metal cap is pressed up against the bridge reinforcing plate.

[0073] The described auxiliary piezoelectric elements and the metal cap installed at the top of the piezoelectric element have space limitation. When implemented, the auxiliary piezoelectric elements should be as close as possible to the centrally located piezoelectric elements. The position of the auxiliary piezoelectric element should not exceed the bridge reinforcing plate, for reason that amplitude at the bridge is at its greatest.

[0074] The described auxiliary piezoelectric elements are connected with the pickup circuit, and a second output electrical lead for outputting sensed signals of the several auxiliary piezoelectric elements is also connected to an external electrical preamplifier. In this scenario, the pickup circuit includes two outputs: one electric lead for one set of piezoelectric elements and a second lead for the second set of piezoelectric elements. The first output lead connects six centrally located piezoelectric elements. The second output lead connects the auxiliary piezoelectric elements. The first output circuit and the second output circuit are connected to a preamplifier. In practice, the first output circuit and the second output circuit can be integrated on the same circuit board or two separate circuit boards; as one of the embodiments, the second output circuit module is a long strip circuit board.

[0075] In the second permutation, the invention comprises two electrical output leads connected to a preamplifier, so that both electrical output signals are sent to the same preamplifier, where they are summed to form a single output.

[0076] Both the centrally located piezoelectric elements and the auxiliary piezoelectric elements are ceramic elements which generate an electrical signal when they are vibrated.

[0077] In summary, technicians within the said field of sensing electrical technology, having read the documentations described herein, would be able to create the same or similar systems which would be protected by the scope of the invention described herein.