US Patent 10377166 Knock type pen

A knock type pen including a housing, a lead which is received in the housing and has an end to which a nib is coupled, and a knock element which protrudes from top of the housing and is pushed, a regulating element which is rotatably installed on an outer circumference of the housing, and a locking element which is provided in the housing and moves up and down by rotation of the regulating element, wherein when the locking element moves up, a press of the knock element is limited by the locking element.