Dust cover assembly for computer keyboard

摘要

A dust cover assembly for a computer keyboard includes a shell body which is attached to a longitudinal side of the keyboard. A slit is longitudinally formed on a peripheral upperside of the shell body. A hollow spindle is rotatably mounted in the shell body. A plug is fitted in a first end of the spindle. A flexible screen has a first end attached to the spindle and has a distal end with an elongated slat mounted thereon. A first cap member is attached to a first end of the shell body. A rod has a first end securely fitted in the first cap member and has a second end mounted in the spindle through the plug. A torsional spring is rotatably mounted around the rod and has a first end securely attached to the plug to rotate therewith and a second end fixed to the second end of the rod. A second hollow cap member is attached to a second end of the shell body and has a slot formed in an upper side thereof. A ratchet gear is received in the second cap member and is engaged with a second end of the spindle to rotate therewith. A switch device is slidably engaged on the second cap member and has a catch which is releasably engaged with the ratchet gear and is restricted to slide along the slot between a first position where the catch is in contact with the ratchet gear, whereby the ratchet gear is limited to rotate in one direction only, and a second position where the ratchet gear is disengaged from the catch, whereby the ratchet gear is capable of rotating in both directions freely.