Abstract: The invention relates to a cylinder lock of the type comprising a cylinder rotatable in a bore of a body and controlled by a key sliding in a longitudinal passage of the cylinder, the entry of the key passage being blocked by a flap which pivots when the key is introduced.According to the invention the said flap comprises a lug upon which there presses a slider which is movable at right angles to the key passage and subject to the action of a spring for returning the flap towards its closure position, the whole being lodged in a front cavity (12) of the head of the cylinder, which cavity is closed by a cap.

Abstract: The invention relates to a bi-stable (toggle) mechanism for a vehicle anti-theft device comprising a lever 20 pivotally mounted by a shaft 21, the said lever being subject to the action of a spring 22 and movable from one stable position through a center position to a second stable position.In the mechanism according to the invention, the said spring 22 consists of a hairpin type spring of which one end 26 is connected to one end of the said lever 20 and the other end 23 mounted so as to pivot at a fixed point 24. The distance between the ends 23,26 of the spring 22 when the lever 20 is in either stable position is greater than the distance between the ends when the lever 20 is at its center position whereby the spring becomes more compressed as the lever approaches the center position where the lever is unstable. The distance between the two ends of the hairpin spring may be less than half that length of the lever which is included between its shaft 21 and the point 24 at which the hairpin spring is located.

Abstract: The invention relates to a master-key piston lock comprising a cylindrical rotor pivoting in a bore of a stator, the said stator comprising radial holes opening into the said bore and in each of which there slides a stator piston spring-loaded towards the said bore, the said rotor comprising an axial key passage into which there open radial holes open at their other extremities at the peripheral surface of the rotor, a right circular-cylindrical rotor piston sliding in each of the said radial holes of the rotor and a key equipped with coded notches co-operating each with the inner extremity of one of the said stator pistons in such manner that the outer extremity of each of the rotor pistons is flush with the peripheral surface of the rotor.The rotor pistons comprise a shoulder with which there can co-operate the notches of a master key.

Abstract: The invention relates to piston-type locks preferably for use with vehicles. In the lock according to the invention the stator comprises an aperture opening at its periphery and into the said longitudinal bore, the said aperture receiving an insert comprising radial passages in each of which there are lodged a pair of pistons and a return spring, the said insert being in two parts sliding telescopically one in relation to the other to reduce the effective length of the said radial passages, the said insert comprising retractable stops for the inner radial extremity of each of the said pairs of pistons, the retraction of the said stops causing the liberation of the said pairs of pistons and the introduction of the inner pistons into the radial bores of the rotor.

Abstract: The invention relates to a cylindrical lock of the type comprising a barrel journalling in the bore of a body.In the lock to which the invention relates, the peripheral surface of the barrel and the surface of the bore in the body comprise an assembly consisting of an elastic longitudinal tongue and a shoulder which are respectively integral with the said two surfaces and which are arranged in such a manner that the said elastic tongue interacts with the said shoulder to lock the barrel so that it cannot move longitudinally in relation to the body.Application to the car industry.

Abstract: The invention relates to an anti-theft device for a motor vehicle, of the type comprising a bolt restored by a spring to the position for locking an element essential to the motion of the vehicle, a lock comprising a stator and a rotor which is actuated by a coded key and which in the course of its rotation causes the bolt to be drawn back into the unlocked position, in order to prevent the bolt from returning to the locked position as long as the key has not been at least partly extracted from the rotor.According to the invention the safety device consists of a sliding and pivoting lever accommodated in the key channel and interacting with a through-slot provided in the key.

Abstract: The invention relates to a bi-stable (toggle) mechanism for a vehicle anti-theft device comprising a lever 5 pivotally mounted by a shaft 6, the said lever being subject to the action of a spring 10 and movable from one stable position through a center position to a second stable position.In the mechanism according to the invention, the said spring 10 consists of a hairpin type spring of which one end 9 is connected to one end of the said lever 10 and the other end 11 mounted so as to pivot at a fixed point 12. The distance between the ends 9, 11 of the spring 10 when the lever 5 is in either stable position is greater than the distance between the point 12 of location of the spring 10 and the point of engagement of the spring end 9 with the lever end when the lever 5 is at its center position whereby the spring becomes more compressed as the lever approaches the center position where the lever is unstable.