Balance pin assembly for a piano key

摘要

A balance pin assembly for mounting a piano key includes a balance pin, a mounting insert, and a self-locking pin. The balance pin has a lower externally threaded base, an intermediate annular shoulder, and an upper elongated stem with a top torque regulating head. The mounting insert has a central bore and is both externally and internally threaded for threading into a hole in a piano keybed rail member and for threadably receiving the base of the balance pin to establish the desired height of the piano key above the rail member. The torque regulating head is used to turn the pin and will shear off if the pin is overtightened in the insert thereby preventing stripping of the internal threads of the insert. The self-locking pin is inserted into a radial hole in the threaded base of the balance pin and projects therefrom so as to frictionally engage the internal threads of the insert to prevent rotational and rocking play of the pin relative to the insert after the pin has been rotatably adjusted relative to the insert to set the desired height of the piano key. The balance pin is composed of a material permitting slight bending of the pin once threaded into the insert to horizontally level the key mounted by the balance pin assembly.