Automatic tuning device

Claim 2

A tuning device for a stringed musical instrument comprising, in combination: a stringed musical instrument body having a set of strings extending thereacross and including an anchor member having means to enable an end of a string to be secured thereto; means mounting the anchor member to the instrument body for movement to vary tension of the string; said anchor member being so constructed and arranged as to exhibit a strain in a degree proportional to the tension of the string; gage means on the anchor member for sensing the degree of strain of the anchor member; drive means for moving the anchor member selectively in a direction to increase or decrease the tension of the string; and control means operatively associated with the means for sensing for operating the drive means in a direction and to an extent to vary the tension in the string to that which will cause a predetermined amount of strain on said anchor member.

Claim 3

A tuning device as set forth in claim 1 wherein said anchor member comprises a lever member having finger means at one end for receiving said end of the string.

Claim 4

A tuning device as set forth in claim 2 including base means forming a fulcrum for the lever member with the other end of the lever member being moved by said drive means to control string tension.

Claim 5

A tuning device as set forth in claim 1 wherein said drive means includes motor means and gear means operated from said motor means and having means for engaging said anchor member.

Claim 6

A tuning device as set forth in claim 4 wherein said gear means comprises a first gear driven by said motor means and a second gear driven by said first gear adapted to be controlled through a rotation of less than 360°, said second gear having pin means for engaging with the anchor member.

Claim 7

A tuning device as set forth in claim 5 wherein said first gear includes a worm gear and said second gear includes a gear that has at least a partial gear track, said pin means engaging with a hooked end of the anchor member.

Claim 8

A tuning device as set forth in claim 1 wherein said strain gage means is disposed fixed to a relatively elongated center portion of said anchor member.

Claim 9

A tuning device as set forth in claim 1 wherein said control means comprises a comparison means including means for establishing a fixed signal corresponding to the desired tuned string tension, which fixed signal is compared to the strain gage means signal.

Claim 10

A tuning device as set forth in claim 8 wherein said comparison means comprises a bridge circuit with the strain gage means having elements forming two branches of the bridge circuit and a fixed and variable resistor forming the other two branches of the bridge circuit, the output from said bridge being a signal of one of positive and negative polarity coupled to said drive means.

Claim 11

A tuning device as set forth in claim 9 wherein said drive means comprises at least a bi-directional motor, the signal from the bridge circuit driving the motor in a direction dependent upon the polarity of the bridge signal.

Claim 12

A tuning device as set forth in claim 10 including amplifier means coupling between the bridge circuit and motor.

Claim 13

A tuning device as set forth in claim 1 including means for selectively enabling the drive means including manually operated means.

Claim 14

A tuning device as set forth in claim 1 wherein the device is for separately tuning a plurality of strings each having associated therewith an anchor means, strain gage means, drive means and control means.

Claim 15

A tuning device for a stringed musical instrument comprising: means for anchoring an end of a string, said anchor means being movable in a manner to vary tension on the string; means operatively associated with the anchor means for moving the anchor means in a selected direction either to increase or decrease the tension on the string; means for sensing the tension on the string; and control means for comparing the sensed tension of the string with that of a predetermined tension, said control means being operatively associated with the moving means to move the anchor means in a direction and to an extent which will tension the string to a value corresponding to that predetermined tension; said means for sensing including switch means supported on said anchor means and having at least two positions indicative of different stress levels of the anchor means.

Claim 16

A tuning device for a stringed musical instrument comprising: means for anchoring an end of a string, said anchor means being movable in a manner to vary tension on the string; means operatively associated with the anchor means for moving the anchor means in a selected direction either to increase or decrease the tension on the string; means for sensing the tension on the string; and control means for comparing the sensed tension of the string with that of a predetermined tension, said control means being operatively associated with the moving means to move the anchor means in a direction and to an extent which will tension the string to a value corresponding to that predetermined tension; said means for sensing including switch means supported on said anchor means and having at least two positions indicative of different stress levels of the anchor means.

Claim 17

A tuning device as set forth in claim 14 wherein said means for sensing senses strain of said anchor means which is in turn related to string tension.

Claim 18

A tuning device as set forth in claim 14 wherein said control means includes electrical null comparison means having said predetermined tension represented by first manually controllable means for establishing a first, desired tension, signal, and the actual string tension represented by second means for establishing a second signal, compared with the first signal.

Claim 19

A tuning device as set forth in claim 16 wherein said first and second means define a bridge circuit the output of which has a signal of either positive or negative polarity coupled to a bi-directional motor forming a part of the moving means.

Claim 20

A tuning device as set forth in claim 14 wherein said switch means comprises a pair of fixed contacts and means supporting the fixed contacts in spaced relationship, and a deflectable contact and means supporting the deflectable contact between the fixed contacts.

Claim 21

A tuning device as set forth in claim 18 including a tuning screw for adjusting the position of the deflectable contact to a position intermediate the two fixed contacts corresponding to a tuned position of the associated string.

Claim 22

A tuning device as set forth in claim 18 wherein the control means includes means responsive to one of a first signal corresponding to closure of the deflectable contact with one of the fixed contacts to move the anchor means in a first direction and a second signal corresponding to closure of the deflectable contact with the other of the fixed contacts to move the anchor means in an opposite direction.

Claim 23

A tuning device as set forth in claim 20 including indicator means for displaying the first and second signals.

Claim 24

A tuning device as set forth in claim 19 including means for commonly tuning all tuning screws associated with all strings in unison.

Claim 25

A tuning device as set forth in claim 22 wherein said means for commonly tuning includes a slide member engageable with all tuning screws.

Claim 26

A tuning device as set forth in claim 14 including biasing means operatively associated with the anchor means for compensating for tension on the anchor means.

Claim 27

A tuning device as set forth in claim 24 wherein the means for moving includes a motor disposed under an outer end of the anchor means.

Claim 28

A tuning device as set forth in claim 25 wherein the anchor means comprises an elongated lever movable via the control means and having an intermediate opening for receiving the biasing means.

Claim 29

A tuning device as set forth in claim 14 wherein the means for sensing tension comprises pizzoelectric means.

Claim 30

A tuning device as set forth in claim 14 wherein the means for sensing tension comprises capacitive sensing means.

Claim 31

A tuning device as set forth in claim 28 including a support means for the capacitive sensing means whereby tension in the anchor means is a function of the distance between capacitive plates forming the capacitive sensing means.

Claim 32

A tuning device as set forth in claim 29 including circuit means comprising tone generator means for driving the capacitive sensing means and means responsive to the signal from the capacitive sensing means for operating motor means bi-directionally as a function of the amplitude of said signal.

Claim 33

A tuning device as set forth in claim 30 wherein the circuit means further comprises rectifier means for providing a DC level corresponding to capacitance and comparator means responsive to the DC level for providing a motor control signal of one of two polarities.

Claim 34

A tuning device as set forth in claim 14 including logic circuit means for providing opposite level signals corresponding to an open position of the switch means and a closed position of the switch means.

Claim 35

A tuning device as set forth in claim 32 including a tune switch for enabling the logic circuit means, said logic circuit means including logic gate determination means.

Claim 36

A tuning device for a stringed musical instrument comprising: means for anchoring an end of a string, said anchor means being movable in a manner to vary tension on the string; means operatively associated with the anchor means for moving the anchor means in a selected direction either to increase or decrease the tension on the string; means for sensing the tension on the string; and control means for comparing the sensed tension of the string with that of a predetermined tension, said control means being operatively associated with the moving means to move the anchor means in a direction and to an extent which maintains the string at a constant frequency of vibration; said anchor member comprising a somewhat elongated lever member having front and back ends and an intermediate pivot, said front end having means receiving the string and said back end having means responsive to the moving means, said lever member also having a bar portion the flexing of which is sensed, said flexing occurring about the intermediate pivot.

Claim 37

A tuning device for a stringed musical instrument comprising: means for anchoring an end of a string, said anchor means being movable in a manner to vary tension on the string; means operatively associated with the anchor means for moving the anchor means in a selected direction either to increase or decrease the tension on the string; means for sensing the tension on the string; and control means for comparing the sensed tension of the string with that of a predetermined tension, said control means being operatively associated with the moving means to move the anchor means in a direction and to an extent which maintains the string at a constant frequency of vibration; said anchor member comprising a somewhat elongated lever member having front and back ends and an intermediate pivot, said front end having means receiving the string and said back end having means responsive to the moving means, said lever member also having a bar portion the flexing of which is sensed, said flexing occurring about the intermediate pivot.

Claim 38

A tuning device for a stringed musical instrument comprising: an anchor member having means to enable an end of a string to be secured thereto; means mounting the anchor member for movement to vary tension of the string; said anchor member being so constructed and arranged as to exhibit a strain in a degree proportional to the tension of the string; strain sensing means associated with the anchor member for sensing the degree of strain of the anchor member; drive means for moving the anchor member selectively in a direction to increase or decrease the tension of the string; and control means operatively associated with the strain sensing means for operating the drive means in a direction and to an extent to maintain the string at a constant frequency of vibration; said anchor member comprising a somewhat elongated lever member having front and back ends and an intermediate pivot, said front end having means receiving the string and said back end having means responsive to the drive means; said lever member having a bar portion the flexing of which is sensed, said flexing occurring about the intermediate pivot.

Claim 39

A tuning device for a stringed musical instrument comprising: an anchor member having means to enable an end of a string to be secured thereto; means mounting the anchor member for movement to vary tension of the string; said anchor member being so constructed and arranged as to exhibit a strain in a degree proportional to the tension of the string; strain sensing means associated with the anchor member for sensing the degree of strain of the anchor member; drive means for moving the anchor member selectively in a direction to increase or decrease the tension of the string; and control means operatively associated with the strain sensing means for operating the drive means in a direction and to an extent to maintain the string at a constant frequency of vibration; said anchor member comprising a somewhat elongated lever member having front and back ends and an intermediate pivot, said front end having means receiving the string and said back end having means responsive to the drive means; said lever member having a bar portion the flexing of which is sensed, said flexing occurring about the intermediate pivot.

Claim 40

A tuning device for a stringed musical instrument comprising: an anchor member having means to enable an end of a string to be secured thereto; means mounting the anchor member for movement to vary tension of the string; said anchor member being so constructed and arranged as to exhibit a strain in a degree proportional to the tension of the string; strain sensing means associated with the anchor member for sensing the degree of strain of the anchor member; drive means for moving the anchor member selectively in a direction to increase or decrease the tension of the string and control means operatively associated with the strain sensing means for operating the drive means in a direction and to an extent to maintain the string at a constant frequency of vibration; said anchor member comprising a lever member having finger means at one end for receiving an end of the string; base means forming a fulcrum for the lever member with the other end of the lever member being moved by said drive means to control string tension.

Claim 41

A tuning device for a stringed musical instrument comprising: an anchor member having means to enable an end of a string to be secured thereto; means mounting the anchor member for movement to vary tension of the string; said anchor member being so constructed and arranged as to exhibit a strain in a degree proportional to the tension of the string; strain sensing means associated with the anchor member for sensing the degree of strain of the anchor member; drive means for moving the anchor member selectively in a direction to increase or decrease the tension of the string and control means operatively associated with the strain sensing means for operating the drive means in a direction and to an extent to maintain the string at a constant frequency of vibration; said anchor member comprising a lever member having finger means at one end for receiving an end of the string; base means forming a fulcrum for the lever member with the other end of the lever member being moved by said drive means to control string tension.

Claim 42

A tuning device for a stringed musical instrument comprising: an anchor member having means to enable an end of a string to be secured thereto; means mounting the anchor member for movement to vary tension of the string; said anchor member being so constructed and arranged as to exhibit a strain in a degree proportional to the tension of the string; strain sensing means associated with the anchor member for sensing the degree of strain of the anchor member; switch means supported on said anchor member and having at least two positions indicative of different stress levels of the anchor means, visual indicator means responsive to said switch means for providing at least two separate visually distinguishable signals corresponding to a sharpness and flatness of the associated string; and means for manually adjusting the string tension in a direction to increase or decrease the tension corresponding to the visually distinguishable signal to retune the string.

Claim 43

A tuning device for a stringed musical instrument comprising: an anchor member having means to enable an end of a string to be secured thereto; means mounting the anchor member for movement to vary tension of the string; said anchor member being so constructed and arranged as to exhibit a strain in a degree proportional to the tension of the string; strain sensing means associated with the anchor member for sensing the degree of strain of the anchor member; switch means supported on said anchor member and having at least two positions indicative of different stress levels of the anchor means, visual indicator means responsive to said switch means for providing at least two separate visually distinguishable signals corresponding to a sharpness and flatness of the associated string; and means for manually adjusting the string tension in a direction to increase or decrease the tension corresponding to the visually distinguishable signal to retune the string.

Claim 44

A tuning device as set forth in claim 37 wherein said means for manually adjusting is for adjusting the position of the anchor member to adjust string tension.

Claim 45

A tuning device as set forth in claim 37 wherein the visually distinguishable signals are of differing colors.

Claim 46

A tuning device as set forth in claim 37 wherein the visual indicator means includes a pair of light indicators.

Claim 49

A method as set forth in claim 41 wherein the switching action is mechanical switching.

Claim 50

A tuning device for a stringed musical instrument comprising: a stringed musical instrument body having a set of strings extending thereacross and having associated therewith, string fastening means including means for anchoring an end of each string, said anchor means being movable in a manner to vary tension on the string; means mounting the anchor means to the instrument body; means operatively associated with the anchor means for moving the anchor means in a selected direction either to increase or decrease the tension on the string; means for sensing the tension on the string; and control means for comparing the sensed tension of the string with that of a predetermined tension, said control means being operatively associated with the moving means to move the anchor means in a direction and to an extent which will tension the string to a value corresponding to that predetermined tension.

Claim 51

A tuning device for a stringed musical instrument comprising: a stringed musical instrument body having a set of strings extending thereacross and having associated therewith, string fastening means including means for anchoring an end of each string, said anchor means being movable in a manner to vary tension on the string; means mounting the anchor means to the instrument body; means operatively associated with the anchor means for moving the anchor means in a selected direction either to increase or decrease the tension on the string; means for sensing the tension on the string; and control means for comparing the sensed tension of the string with that of a predetermined tension, said control means being operatively associated with the moving means to move the anchor means in a direction and to an extent which will tension the string to a value corresponding to that predetermined tension.