US3589154A - Antitheft lock key safety latching devices - Google Patents

Abstract

The safety device comprises a resilient member which is pivoted to the fixed body of the lock of an antitheft device, externally thereof each end of the resilient member engaging respectively an abutment element of said fixed body and an abutment element of a rotary cylinder plate of the lock, the expansion of said resilient member causing said cylinder and therefore the antitheft device to be resiliently restored to a position spaced angularly a few degrees from the cylinder position permitting the withdrawal of the key, whereby the user must compulsorily exert a non-negligible effort for restoring the key and cylinder to the withdrawal position.

Description

Unite States Patent Societe DExpiaitan'on Des Brevets Neirnan Neuilly-sur-Seine (Hauts de Seine), France [73] Assignee [32] Priority Mar. 10, 1969 [33] France [31 1 69 06579 [54] ANTITHEFI LOCK KEY SAFETY LATCHING 431, 432, 447, 441, DIG. 62, DIG. 54; 200/44, 42, 61.54,61.67

[ 56] References Cited UNlTED STATES PATENTS 3,529,456 9/1970 McWilliams 70/447 FOREIGN PATENTS 678,167 8/1952 Great Britain 70/447 850,866 9/1952 Germany 70/447 1,082,156 3/1954 Germany 70/389 Primary Examinerlan A. Calvert Assistant Examiner-Robert L Wolfe Attorney-Stevens, Davis, Miller and. Mosher ABSTRACT: The safety device comprises a resilient member which is pivoted to the fixed body of the lock of an antitheft device, externally thereof each end of the resilient member engaging respectively an abutment element of said fixed body and an abutment element of a rotary cylinder plate of the lock, the expansion of said resilient member causing said cylinder and therefore the antitheft device to be resiliently restored to a position spaced angularly a few degrees from the cylinder position permitting the withdrawal of the key, whereby the user must compulsorily exert a non-negligible effort for restoring the key and cylinder to the withdrawal position.

ANTITI'IEFT LOCIK KEY SAFETY LATCHING DEVICES The present invention is concerned with safety-lock antitheft devices of the type mounted on most modern motor vehicles, and notably with devices of the type wherein the withdrawal of the key is attended automatically by the engagement ofa lock bolt into a member to be locked, for example the steering column ofthe vehicle.

It is known that a key cannot be removed from, or inserted int0, a cylinder lock, whether of the pin tumbler or disc tumbler type, unless the pins or the discs register exactly with the recesses provided therefor in the fixed body of the lock.

In certain countries there is a legal obligation to provide an additional safety feature in antitheft locks of this character with a view to prevent the untimely withdrawal of the key controlling the antitheft device when this key constitutes at the same time a detachable abutment member for locking the lock bolt.

It is the essential object of the present invention to provide a device capable of providing a satisfactory solution to this problem.

The device applicable to antitheft devices comprising a cylinder lock having a fixed lock body and a rotary inner cylinder provided with an antitheft control plate and actuatable by means of a notched key, includes a resilient member pivoted to the fixed lock body, externally thereof, said fixed body and said cylinder plate being each provided with a stop engageable by one end of said resilient member, respectively, the expansion of said resilient member being adapted resilient y to urge said cylinder and said antitheft control plate to a position spaced a few degrees from the cylinder position permitting the .key withdrawal, whereby the driver of the vehicle is compelled to make a far from negligible effort for restoring the key and the lock cylinder to the position permitting this withdrawal.

The invention will now be described more in detail with reference to the accompanying drawing illustrating diagrammatically by way of example typical forms of embodiment thereof. In the drawing:

FIG. 1 is a diagrammatic cross-sectional view showing the cylinder and the fixed body of a conventional pin tumbler safety lock, the section being taken along the axis of a pin with the latter positioned in alignment with its two bore sections, thus permitting the withdrawal of the key;

FIG. 2 is another sectional view showing the same lock after the cylinder has been rotated a few degrees in the fixed body;

FIGS. 3 and 4 are cross-sectional views showing a known disc tumbler cylinder, the sections being taken across one disc;

FIGS. 5 and 6 illustrate the lock cylinder of FIGS. 3 and 4 in the same positions, respectively, according to one form of embodiment of the invention, and

FIG. 7 is a view similar to FIGS. 5 and 6 but modified form of embodiment.

The last three FIGS. of the drawing are external lateral views of the fixed body or similar element of the safety lock, assumed to be removed from the body of the antitheft device or from the body of the lock case.

Referring first to FIG. 1, the pin tumbler safety lock of conventional type illustrated therein comprises as usual a cylinder or plug 4 and radial pin tumblers, of which one is shown at 4 as being urged by a spring 2 towards the cylinder axis, the cylinder being adapted on the other hand to be engaged by a key 3 for rotating the cylinder inside a fixed lock body 5.

In FIG. 2 the key 3 and therefore the cylinder 4 have been rotated in the counterclockwise direction through a small angle, for example a few degrees; thus, the base of pin 1 engages the inner cylindrical surface of the cylinder-receiving bore of fixed body 5. Under these conditions the key 3 cannot be withdrawn since on the one hand the key edge is wedged against the inner end or point Ia of pin tumbler l, and on the other hand the base or outer end of pin I abuts against said cylindrical surface.

In the case of a known type of disc tumbler cylinder lock as showing a shown in FIGS. 3 and 4 a small angular movement shown in FIG. 4 is also sufficient for safety preventing the withdrawal of key 3. The force of lateral spring 2 urging the disc 4a 0utwards assists in causing the frictional engagement between the key and the various central recesses of the discs.

In each one of the two cases contemplated hereinabove it is clear that a resilient abutment is created a few degrees before attaining the position permitting the free withdrawal of the key.

It is therefore definitely necessary to provide some means for overcoming this elastic resistance when moving the key to the positions permitting the key withdrawal, which are shown in FIGS. 1 and 3. This means is constituted by the device of this invention, as illustrated in FIGS. 5, 6 and 7.

In the device shown in FIGS. 5 and 6, a plate 6 solid with the cylinder and then rotatably rigid with the key 3 comprises a peripheral stud or projection 7, and the fixed body 5 of the lock is formed with a projection 9 and carries an hairpin spring 8 securecl'at its elbow to a pin 11; this spring 8 engages with one arm stud 7 and with the other arm the projection 9, thus constantly urging the cylinder unit to one of the positions shown in FIGS. 2 and 4, corresponding to FIG. 6. Thus, it is clear that to restore the key 3 in the position shown in FIG. 5 the user must exert an effort sufficient to compress the hairpin spring 8 until this position is attained, so that the key can be removed from the lock.

Thus, in the position shown in FIG. 6 a resilient abutment device is created which, as shown in FIGS. 2 and 4, counteracts the rapid and untimely withdrawal of the key.

FIG. 7 illustrates a modified form of embodiment of the device shown in FIG. 5, wherein in lieu of the hairpin spring 8 a coil compression spring 8' is used this spring 8' reacts against a fixed element 12 carried by the outer surface of the lock body 5 and constantly urges an arm 10 pivoted to the same body about a pin II, the outer end of arm 10 transmitting the force of spring 8' cylinder plate 6.

lf the antitheft device comprises in the known fashion a switch controlling the ignition and starter motor of the vehicle, the sameprinciple as set forth hereinabove may be used for restoring the lock cylinder from the Start" position to the Ignition position.

Although the present invention has been described in conjunction with preferred embodiments, it is to be understood that modifications and variations may be resorted to without departing from the spirit and scope of the invention, as those skilled in the art will readily understand. Such modifications and variations are considered to be within the purview and scope of the invention and appended claims.

What I claim as new is:

1. A safety device for preventing the untimely withdrawal of the key from antitheft devices, notably in a motor vehicle, this antitheft device comprising a lock having a fixed body and a rotary cylinder provided with a plate for controlling the anto the stud 7 carried by the titheft member by means of the key, wherein a resilient member is pivoted to the fixed body of the lock, externally thereof, said fixed body and said cylinder plate carrying each an abutment element engaged by one end of said resilient member, respectively, the expansion of said resilient member causing said cylinder and therefore the antitheft device to be resiliently restored to a position spaced angularly a few degrees from the cylinder position permitting the withdrawal of the key, whereby the user must compulsorily exert a non negligible effort for restoring the key and cylinder to the withdrawal position.

2. Device as set forth in claim 1, wherein said resilient member is an hairpin spring.

3. Device as set forth in claim 1, wherein said resilient member is a coil compression spring associated with a pivoted arm.

4. Device as set forth in claim 1, wherein said antitheft device comprises a switch controlling the starting and ignition of the vehicle engine, the lock key permitting of restoring the lock cylinder from the Start" position to the "Ignition" posi- IIOII.

Claims (4)

1. A safety device for preventing the untimely withdrawal of the key from antitheft devices, notably in a motor vehicle, this antitheft device comprising a lock having a fixed body and a rotary cylinder provided with a plate for controlling the antitheft member by means of the key, wherein a resilient member is pivoted to the fixed body of the lock, externally thereof, said fixed body and said cylinder plate carrying each an abutment element engaged by one end of said resilient member, respectively, the expansion of said resilient member causing said cylinder and therefore the antitheft device to be resiliently restored to a position spaced angularly a few degrees from the cylinder position permitting the withdrawal of the key, whereby the user must compulsorily exert a non negligible effort for restoring the key and cylinder to the withdrawal position.

2. Device as set forth in claim 1, wherein said resilient member is an hairpin spring.

3. Device as set forth in claim 1, wherein said resilient member is a coil compression spring associated with a pivoted arm.

4. Device as set forth in claim 1, wherein said antitheft device comprises a switch controlling the starting and ignition of the vehicle engine, the lock key permitting of restoring the lock cylinder from the ''''Start'''' position to the ''''Ignition'''' position.

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