Push-pull door lock having latch unit

A push-pull door lock having a latch unit located inside a door in such a way as to allow the door to be open and closed against a door frame according to pushing or pulling of handles, wherein the latch unit comprises:

• a unit case built in the door in such a way as to face the door frame;
• a movable bracket linearly movable in the unit case;
• an actuating cam rotatable in place in the movable bracket in such a way as to be capable of rotating according to the pushing or pulling of the handles to allow the movable bracket to linearly move, the actuating cam having a cam protrusion configured to push the movable bracket backward when the actuating cam rotates;
• an elastic member provided in the movable bracket in such a way as to be elastically supported against the movable bracket;
• a support block elastically supported against the elastic member and locked onto the movable bracket in such a way as to be linearly movable along with the movable bracket, the support block having a coupling protrusion;
• a connecting shaft provided to pass through the support block and supported by the support block such that the connecting shaft is movable together with the support block when the support block moves backward;
• a latch bolt rotatably coupled to the connecting shaft and having:
• an angle restriction groove formed in a portion where the connecting shaft is connected in such a way as to restrict the rotating angle thereof;
• and
• a coupling groove corresponding to the coupling protrusion of the support block,
• wherein, when the actuating cam rotates to move the movable bracket backward, the support block is movable backward together with the movable bracket, and the connecting shaft is movable backward together with the support block, such that the coupling protrusion can escape from the coupling groove, thereby allowing the latch bolt to freely rotate on the connecting shaft;
• and
• a fixed plate fixedly coupled to the unit case and having a through hole adapted to pass the latch bolt therethrough.