This invention is an insurance door lock for house. It is composed of internal and external front plates, internal and external handles, spring lock core, internal and external cams, control pin, upper and lower spring pins and holed plates of door frame. The lower spring pin is connected to the internal and external cams. The external and internal cams are turned by a key and control handle respectively. A control pin is installed between upper and lower pins. The lower end of the control pin is in touch with the inclined plane of the lower spring pin and the upper spring pin is controlled by the movement of lower spring pin. The insurance door lock can perform three insurance functions: internal insurance, external insurance and lower spring pin locking and controlling upper spring pin. It features beautiful appearance, good firmness and durability, and good insurance effect on guarding against thief. |