Stringed musical instrument using spring tension

Abstract

A stringed musical instrument employs springs to apply tension to corresponding musical strings. Each spring is chosen and configured for its ability to impart a string tension generally matched to the appropriate tension of the string at perfect tune. Preferably, the spring is selected and arranged so that the tension in the string maintains at or near perfect tune even as the string elongates or contracts over time. In one embodiment, once a string is placed in appropriate tune, a mechanical visual indicator is set. As such, if tune of the string changes due to string elongation or contraction, the change is reflected by misalignment of the mechanical visual indicator even if the change cannot be aurally detected. Perfect tune can be reestablished by realigning the indicator. In another embodiment, a force modulating member is interposed between a spring and its corresponding musical string. The force modulating member is adapted so that the tension actually applied to the string by the spring is not linearly related to the force exerted by the spring as the spring changes in length.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows an embodiment of a guitar employing a string mounting system depicted schematically and having aspects described herein.

FIG. 2 shows an embodiment of a guitar employing an embodiment of a string mounting system having aspects of the present invention.

FIG. 3 is a close up view of the guitar of FIG. 2 taken along lines 3-3, and showing portions of the string mounting system partially cutaway.

FIG. 3A is a close up view of a stop member in a position relative to a corresponding tube and spring connector when a corresponding string has just been placed in correct tune.

FIG. 3B shows the arrangement of FIG. 3A after the stop member has been moved to align the stop tune indicator with the tube reference indicator.

FIG. 4 is a side view of the portion of the guitar shown in FIG. 3.

FIG. 5 is a close up perspective view of another embodiment of a guitar with a string mounting system having aspects in accordance with the present invention.

FIG. 6 is a schematic side view of a string tensioner used in accordance with the embodiment illustrated in FIG. 5.

FIG. 6A is a diagram schematically representing certain relationships of the embodiment illustrated in FIG. 6.

FIG. 7 is a perspective view of the string tensioner of FIG. 6.

FIG. 8 is another perspective view of the string tensioner of FIG. 6.

FIG. 9 is a perspective view of the string tensioner of FIG. 6 but showing a shuttle 250 of the string tensioner disposed in a different position.

FIG. 10 is a perspective view showing a plurality of string tensioners arranged into the string mounting system of a guitar.

FIG. 11 is a rear perspective view of the string tensioners of FIG. 10.

FIG. 12 is a perspective view of a back side of the guitar of FIG. 5 showing a portion of the string tensioner system disposed in a cavity formed in the guitar body.

FIG. 13 is a graph depicting the change in spring force as the arm of the spring tensioner of FIG. 6 moves counter clockwise.

FIG. 14 is a graph depicting the change in effective lever arm of the spring as the arm of the spring tensioner of FIG. 6 moves counter clockwise.

FIG. 15 is a graph depicting the change in effective string tension resulting from the effects shown in FIGS. 13 and 14 as the arm of the spring tensioner moves counter clockwise.

FIG. 16 is a perspective view of another embodiment of a guitar employing an embodiment of a string tensioning system having aspects of the present invention.

FIG. 17 is a top view of the guitar of FIG. 16.

FIG. 18 is a side view of yet another embodiment of a string tensioner having aspects in accordance with the present invention.

FIG. 19 is a top view of another embodiment of a string mounting system employing tensioners as in FIG. 18.

FIG. 20 is a schematic view of another embodiment of a string mounting system having aspects in accordance with the present invention.

FIG. 21 is a schematic view of yet another embodiment of a string mounting system having aspects in accordance with the present invention.

FIG. 22 is a schematic view of still another embodiment of a string mounting system having aspects in accordance with the present invention.

FIG. 23A is a side view of yet another embodiment of a string tensioner having aspects in accordance with the present invention

FIG. 23B is a side view of the string tensioner of FIG. 23A showing the spring force modulating member portion in a different rotational position.

Claims

1. A stringed musical instrument, comprising: a musical string having first and second ends;a first receiver adapted to receive the first end and hold the first end in an adjustably fixed position;a string mounting system adapted to receive the second end, the string mounting system comprising a spring assembly configured to apply a tension to the second end of the string so as to hold the string at a perfect tune tension;wherein the string mounting system is adapted so that as the second end of the musical string moves longitudinally over time due to string elongation or contraction, the string tension remains within a desired range defined about the perfect tune tension.

2. A stringed musical instrument as in claim 1, wherein the desired range is within about 90% of the perfect tune tension.

3. A stringed musical instrument as in claim 2, wherein the string mounting system is adapted so that the spring maintains the string tension within the desired range when the second end moves longitudinally less than about 5% of the total string length.

4. A stringed musical instrument as in claim 3, wherein the perfect tune tension is between about 5 pounds and 200 pounds.

5. A stringed musical instrument as in claim 1, wherein the desired range is within about 98% of the perfect tune tension.

6. A stringed musical instrument as in claim 1, wherein the desired range is within about 99% of the perfect tune tension.

7. A stringed musical instrument as in claim 1, wherein the desired range is within about 99.5% of the perfect tune tension.

8. A stringed musical instrument as in claim 1, wherein the spring assembly comprises a single spring.

9. A stringed musical instrument as in claim 1, wherein the spring assembly comprises a plurality of springs.

10. A stringed musical instrument as in claim 1, wherein the mechanical interface comprises a force modulating member that pivots as the second end of the string moves longitudinally, and the force modulating member is adapted to pivot within a range of about 10 degrees of rotation.

11. A stringed musical instrument as in claim 10 additionally comprising a roller bridge disposed forwardly of the mechanical interface, the roller bridge comprising a roller and an axle, the roller being adapted to support the string and rotate about the axle, wherein a ratio of a diameter of the roller to a diameter of the axle is greater than about 20.

12. A stringed musical instrument as in claim 10, wherein the mechanical interface comprises a stop configured to prevent rotation in a rotational direction beyond a defined position.

13. A stringed musical instrument as in claim 12, wherein the mechanical interface comprises a sensor adapted to detect when the stop is engaged to prevent rotation and to generate a signal upon detection of such engagement.

14. A stringed musical instrument as in claim 1, wherein the spring assembly is configured to provide substantially the entire tension load in the string.

15. A stringed musical instrument as in claim 14, wherein the spring assembly comprises a single spring.

16. A stringed musical instrument as in claim 14, wherein the spring assembly comprises a plurality of springs.

17. A stringed musical instrument as in claim 16, wherein the spring assembly comprises a first spring and a second spring, the first spring adapted to support a greater magnitude of tension in the string than the second spring, the second spring connected to the string through the mechanical interface so that a mechanical advantage or disadvantage of the second spring relative to the spring can be adjusted.

18. A stringed musical instrument, comprising: a musical string;a spring; anda mechanical interface interposed between the string and the spring, the mechanical interface adapted to communicate force from the spring to the string so that the spring provides substantially all of the tension in the musical string;wherein the mechanical interface is adapted to modify the force exerted by the spring so that a magnitude of tension in the musical string differs from a magnitude of force exerted by the spring.

19. A stringed musical instrument as in claim 18, wherein the mechanical interface is configured so that a percent change in the force exerted by the spring corresponds to a percent change in the tension in the string, and the magnitude of the percent change in the tension in the string is less than the magnitude of the percent change in the force exerted by the spring.

20. A stringed musical instrument as in claim 19, wherein the mechanical interface is adapted so that the magnitude of the change in tension applied to the string is not linearly related to the corresponding magnitude of the change in force exerted by the spring.

21. A stringed musical instrument as in claim 19, wherein the mechanical interface comprises a cam.

22. A stringed musical instrument as in claim 21, wherein the cam comprises a string receiver.

23. A stringed musical instrument as in claim 19, wherein the mechanical interface connects to the spring and the string so that the spring force acts with a mechanical advantage or disadvantage relative to the string.

24. A stringed musical instrument as in claim 23, wherein the mechanical interface is configured so that as the magnitude of spring force increases, the mechanical advantage of the spring with relation to the string decreases.

25. A stringed musical instrument as in claim 24, wherein the mechanical interface comprises a cam having a string receiver.

26. A stringed musical instrument as in claim 25, wherein the string receiver has a constant radius.

27. A stringed musical instrument as in claim 25, wherein the string receiver has a varying cam radius.

28. A stringed musical instrument, comprising: a musical string; anda string mounting system comprising a spring assembly having a spring;wherein a force from the spring assembly is communicated to the string so that the spring assembly provides substantially all of the tension in the musical string; andwherein the string mounting system is adapted to condition the force exerted by the spring along a changing moment arm so that a change in the magnitude of force exerted by the spring results in a change in magnitude of tension applied by the spring assembly to the string that is less than the change in magnitude of force exerted by the spring.

29. A stringed musical instrument as in claim 28, wherein the string mounting system comprises a mechanical interface interposed between the spring and the string, and wherein the mechanical interface conditions the spring force relative to the string tension.

30. A stringed instrument as in claim 29, wherein the mechanical interface comprises a spiral-tracked conical pulley, and the musical string is supported in the track.

31. A stringed musical instrument, comprising: a musical string; anda string mounting system;the string mounting system comprising a string mount, a spring assembly having a spring, and a mechanical interface between the string mount and the spring assembly, the interface adapted so that the spring assembly provides substantially all of the tension in the musical string;wherein the spring is a constant force spring comprising a rolled, pre-stressed ribbon adapted to exert a force that varies less than 1% over a maximum elongation of the musical string.

32. A stringed instrument as in claim 31, wherein the mechanical interface comprises a moment arm disposed operatively between the spring and the string, and the moment arm can be adjusted to tune the mechanical advantage or disadvantage provided to the spring relative to the string.

33. A stringed instrument as in claim 32, wherein the constant force spring is chosen to exert a substantially constant force substantially equal to a perfect-tune tension of the musical string.