Lock device with concealed mounting screws

A lock device for securing a door comprising:

• a housing;
• a strike attached to the door frame;
• a locking member movably provided within said housing;
• an outside lock cylinder;
• a thumbturn rotatably provided into a circular hole formed on the front portion of said housing;
• a mechanism operatively connecting said locking member and said outside lock cylinder and between said locking member and said thumbturn for actuating the locking bolts of said locking member to releasably interlock said housing with said strike;
• a cover member being adapted to be detachably mounted at the open rear side of said housing and having a first engaging means provided thereon;
• an inside lock cylinder rotatably provided into a shaft of said thumbturn including a restraint means for restraining the turning movement of said thumbturn;
• a mounting member attached to the inside surface of said door having provided thereon a second engaging means adapted to engage with said first engaging means;
• and
• a screw means including an adjusting screw and a support member being fixedly attached to said mounting member and threadably engaged with said adjusting screw, the head of said adjusting screw being located between a side wall of said housing and a stop formed near one side of said cover member when said housing along with said cover member is placed onto said mounting member to cover said mounting member;
• the arrangement being such that said housing together with said cover member will move relative to said mounting member to cause said first engaging means to engage with or disengage from said second engaging means when said adjusting screw is turned to move in a direction with the head thereof pressing against said side wall or said stop, thereby said housing is mounted on or dismounted from said mounting member.