Abstract: A mechanism to prevent an adjustment knob associated with a piece of equipment (e.g. musical instrument or amplifier) from being moved accidentally includes an inner hub held in place on an adjustable shaft. An knob body fits concentrically over the inner hub, and is biased into position over the hub. The bottom of the knob body has locking structure which lockingly but releasingly cooperates with locking structure associated with the piece of equipment to which the shaft is affixed. A biasing structure such as a spring retains the knob body in a first, locked, position, in which the knob body is prevented from rotating, which in turn prevents rotation of the adjustable shaft. However, when the knob body is pulled away from the locking structure against the spring force, the knob body can be rotated, which in turn rotates the hub and shaft shaft. Releasing the knob body allows the biasing structure to urge the knob body back into engagement with the locking structure.

Abstract: A mechanism to prevent a knob from being moved accidentally. An inner hub is held in place on the adjustable shaft. An knob body fits concentrically over the inner hub, and is biased into position over the hub. The bottom of the barrel has locking structure which lockingly but releasingly cooperates with locking structure associated with the piece of equipment (e.g. musical instrument or amplifier) to which the shaft is affixed. The biasing means retains the knob body in a first, locked, position, in which the knob body is prevented from rotating, which in turn prevents rotation of the adjustable shaft. However, when the knob body is pulled away from the locking structure against the spring force, the knob body can be rotated, which in turn rotates shaft. Releasing the knob body allows the spring to urge the knob body back into engagement by the locking structure.