Patent ID: 7065991

Claim:
A safety lock for doors, comprising: a base cover, a lock cover and one strike plate, the said base cover and lock cover defining an inner space, the base cover being attached the lock cover by securing members; a lock mechanism located in said inner spaces and including a lock cylinder which comprises a drag piece; wherein said lock mechanism further comprises: a portion of the base cover, and walls perpendicular to said base cover which together form a substantially rectangular box, having two parallel side walls with crenellations, said side walls being perpendicular to said strike plate; an internal mechanism which comprises a grooved lower plate, a locking plate, a pin, a spring having a wire loop shape, and a grooved upper plate, the grooves in the lower and upper plates being matched to each other, wherein said internal mechanism is positioned inside said rectangular box and wherein holes are provided in the lower and upper plate; a plurality of retaining pins; a lock bolt attached to the lower and upper plates via the retaining pins; the locking plate having a side hole within which the pin is housed wherein a teeth formation is formed on the external periphery thereof, the spring being fitted into a recess of the locking palate adjacent to the pin, the pin being housed within the holes in the lower and upper plate; said pin forming an axis of said spring and for the rotation shaft for said locking plate, said locking plate being disposed between said lower and upper plates and being connected to the lower and upper plates by said pin; wherein said locking plate is driven by said drag piece of said lock cylinder on an internal periphery thereof and which locks through the teeth on the outer periphery thereof in the crenellations of one of said parallel side walls; and wherein the action of said drag piece of the cylinder on said locking plate releases said internal mechanism and, under the pressure of said spring on the locking plate, locks the inner mechanism in the crenellations of one of said parallel side walls in all positions thereof including, a first locking position, a second locked position after the first turn and a third locked position after the second turn.