Fixed adjustment dial

A rotary controller selectively-disengageable locking knob assembly, comprising:

• a hub having a longitudinal axis and an axial bore extending at least partially through the hub along the longitudinal axis, wherein the axial bore is configured to receive a shaft of the rotary controller arranged in or on a device surface;
• the hub including a radial bore extending from an outer surface of the inner hub to the axial bore, wherein the radial bore is perpendicular to the axial bore;
• a knob concentrically disposed about at least a portion of the hub, wherein the knob includes:
• at least one central bore structured to receive at least a portion of the hub;
• a radial slot alignable with the radial bore;
• and
• a circumferential bottom surface having a first engagement arrangement comprising first projections;
• a post threadedly engaged with the radial bore so as to secure the hub to the shaft of the rotary controller, and projecting radially outwardly through the radial slot, such that rotation of the knob induces a rotation of the hub via contact of the post with the radial slot;
• a base having a first side securely fastenable to the device surface and a circumferential second surface having a second engagement arrangement comprising second projections configured to interact with the first engagement arrangement to prevent relative rotational movement between the base and the knob when the first engagement arrangement is in contact with the second engagement arrangement;
• a biasing member arranged within the knob and structured and arranged to bias the first engagement arrangement into contact with the second engagement arrangement,
• wherein the knob is axially moveable on the hub to selectively disengage the first engagement arrangement from contact with the second engagement arrangement.