A self-locking tuner is used to tune the strings of a musical instrument. The self-locking tuner is disposed in a headstock of the stringed musical instrument. The self-locking tuner has an inner string post, outer string post disposed over the inner string post, locking pin extending above the inner string post and through the outer string post to the opening, and insert disposed around the outer string post. Alternatively, a cast housing is disposed around the outer string post with a stop to unlock a string. The string extends through an opening in the outer string post. The insert or cast housing has a stop to unlock the string. The outer string post has a rotational stop which contacts the stop to unlock the string. The insert is disposed in a headstock with the tab disposed in a slot formed in a surface of the headstock.

A tuning machine for a stringed instrument comprising: an input shaft having a first end, and an opposite second end having an eccentric, the input shaft being rotatable in response to an input from a user; a gear member or rotor with a central axial bore to receive the eccentric to move the rotor though a circular motion as the input shaft rotates, the rotor having a first or upper gear portion with external first lobes, and a second or lower gear portion with external second lobes; a first or upper ring gear having internal first teeth positioned around the first lobes of the first gear portion; a second or lower ring gear separate from the upper ring gear and having internal second teeth positioned around the second lobes, said upper and lower ring gears being larger than the rotor to accommodate the circular motion of the rotor within said ring gears such that at least one of the first lobes meshes with at least one of the internal first teeth, and at least one of the second lobes meshes with and drives at least one of the internal second teeth of the lower ring gear as the rotor moves through its circular motion to rotate the lower ring gear about its central axis; and a string post driven by the lower ring gear to wind a string of the instrument as a result of rotation of the input shaft in one direction and unwind the string as a result of rotation of the input shaft in an opposite direction.

A tuning machine for a stringed instrument comprising: an input shaft having a first end, and an opposite second end having an eccentric, the input shaft being rotatable in response to an input from a user; a gear member or rotor with a central axial bore to receive the eccentric to move the rotor though a circular motion as the input shaft rotates, the rotor having a first or upper gear portion with external first lobes, and a second or lower gear portion with external second lobes; a first or upper ring gear having internal first teeth positioned around the first lobes of the first gear portion; a second or lower ring gear separate from the upper ring gear and having internal second teeth positioned around the second lobes, said upper and lower ring gears being larger than the rotor to accommodate the circular motion of the rotor within said ring gears such that at least one of the first lobes meshes with at least one of the internal first teeth, and at least one of the second lobes meshes with and drives at least one of the internal second teeth of the lower ring gear as the rotor moves through its circular motion to rotate the lower ring gear about its central axis; and a string post driven by the lower ring gear to wind a string of the instrument as a result of rotation of the input shaft in one direction and unwind the string as a result of rotation of the input shaft in an opposite direction.

A foldable stringed instrument, for example in the form of a travel guitar that folds mid-neck to assume a reduced profile is described. The mid-neck folding is accomplished in a symmetrical manner about a three-part hinge located in the neck to configure the travel guitar into a reduced profile. The bridge assembly can be translated longitudinally relative to the head of the guitar to allow sufficient detensioning of the guitar strings to enable an upper portion of the neck to be folded away from a lower portion of the neck and/or body to assume a reduced profile. To deploy the travel guitar for playing, the upper portion of the neck is unfolded into alignment with the lower portion of the neck and/or body, and the bridge assembly translated longitudinally relative to the head and locked in position to allow the guitar to be tuned for playing.

An instrument string guide for changing the path of a string on a musical instrument is disclosed. The instrument string guide engages the musical instrument string between the end of operational length and point of string termination. This device comprises a base 1 and tapered radiused slot 2 to attach to the musical instrument. The tapered radiused slot 2 keeps the devise attached to the musical instrument. The tapered radiused slot also guides the string around the radiused edge more easily to reduce friction. The instrument string guide rests against a part of the instrument to become stationary.

An instrument string guide for changing the path of a string on a musical instrument is disclosed. The instrument string guide engages the musical instrument string between the end of operational length and point of string termination. This device comprises a base 1 and tapered radiused slot 2 to attach to the musical instrument. The tapered radiused slot 2 keeps the devise attached to the musical instrument. The tapered radiused slot also guides the string around the radiused edge more easily to reduce friction. The instrument string guide rests against a part of the instrument to become stationary.

A foldable stringed instrument, for example in the form of a travel guitar that folds mid-neck to assume a reduced profile is described. The mid-neck folding is accomplished in a symmetrical manner about a three-part hinge located in the neck to configure the travel guitar into a reduced profile. The bridge assembly can be translated longitudinally relative to the head of the guitar to allow sufficient detensioning of the guitar strings to enable an upper portion of the neck to be folded away from a lower portion of the neck and/or body to assume a reduced profile. To deploy the travel guitar for playing, the upper portion of the neck is unfolded into alignment with the lower portion of the neck and/or body, and the bridge assembly translated longitudinally relative to the head and locked in position to allow the guitar to be tuned for playing.

A stringed instrument tuner that senses the vibration of all the strings of the instrument independently and simultaneously via ultraviolet reflective light sensors that are immune to interference from ambient alternating-current lighting. The pitches of the strings are then measured continuously in real-time and transmitted wirelessly to a receiver that simultaneously graphically displays how far out-of-tune all of the strings are so that the musician can instantly see which strings need tuning and tune them quickly. The receiver may be a smartphone, smartwatch, smart glasses, computer, self-tuning system, or a dedicated wearable receiver-display unit.

A stringed instrument tuner that senses the vibration of all the strings of the instrument independently and simultaneously via ultraviolet reflective light sensors that are immune to interference from ambient alternating-current lighting. The pitches of the strings are then measured continuously in real-time and transmitted wirelessly to a receiver that simultaneously graphically displays how far out-of-tune all of the strings are so that the musician can instantly see which strings need tuning and tune them quickly. The receiver may be a smartphone, smartwatch, smart glasses, computer, self-tuning system, or a dedicated wearable receiver-display unit.

An apparatus for emulating a variety of string instruments with a variety of configurations in order to measure the resulting, actual tension of a string on that instrument. The tension may be measured in real-time.