Low profile auto-locking pinch/turn adjustment knob

An adjustment knob for adjusting an optical, mechanical, or electronic device, comprising:

• a spindle supported on the device for rotation about an axis, the spindle operatively associated with an adjustment mechanism that controls a setting of the device;
• and
• a releasable lock mechanism supported on the spindle for rotation therewith, the lock mechanism including:
• a button manually depressible in a generally radial direction from a radially outward locked position at which the lock mechanism constrains the spindle to prevent it from rotating relative to the device, to a radially inward unlocked position that releases the lock mechanism and allows the spindle to be rotated, and
• an actuator shaft connected to the button and extending radially inward through a drive hole in an outer side wall of the spindle, the actuator shaft transmitting a force applied to the button to drive the lock mechanism and to rotate the spindle.