Lock for a door of a motor vehicle

A lock is provided for a door of a motor vehicle. The lock includes a closing mechanism designed for coupling with a lock striker along a direction of relative coupling. The closing mechanism includes a supporting body having a housing seat for receiving an engagement portion of the lock striker. An elastically compliant buffer delimits the housing seat at least in the aforesaid direction of relative coupling in order to define a damped arrest of the engagement portion of the lock striker. The buffer is coated on its surface, in an area of interaction with the engagement portion of the lock striker by a rigid protective shield. The shield is fixedly secured to the buffer.

TECHNICAL FIELD

The present invention relates to a lock for a door of a motor vehicle.

It is pointed out that the term “door” is used, in the present description and in the ensuing claims, in its widest sense to indicate any element that can move between an opening position and a closing position of an access opening to an internal compartment of a motor vehicle. The aforesaid term therefore comprises the side doors of the motor vehicle, the bonnet or the boot or the hatchback.

BACKGROUND ART

As is known, closing systems for doors of motor vehicles basically comprise a lock mounted on the door and a lock striker mounted in a fixed portion of the bodywork in the proximity of the opening of the door itself (or, more rarely, vice versa).

The lock comprises a closing mechanism designed to co-operate with the lock striker so as to obtain a relative blocking between the lock and the lock striker itself when the door is closed.

Currently, there is a widespread use of lock strikers of the type comprising a U-shaped element having opposite ends riveted onto a supporting plate. The U-shaped element is basically made up of two cylindrical portions, which extend orthogonally from the supporting plate and are radiused, on the opposite side, by a connecting portion set transverse to them.

The closing mechanism comprises a fork and a pawl which are hinged to respective pins fixed to a supporting body designed to be fixed to the door of the motor vehicle.

The fork is designed to couple in a releasable way with one of the cylindrical portions of the lock striker, hereinafter referred to as “engagement portion”, whilst the pawl is designed to block the fork, in a releasable way, in a position of closing on the lock striker.

In particular, the supporting body and the fork define respective U-shaped seats for housing and blocking the engagement portion of the lock striker. Each of said seats defines, at one end, an entry section for the engagement portion of the lock striker and is delimited, at an opposite end, by a bottom wall, which defines the position of arrest of said engagement portion.

The fork is pushed by a corresponding spring in the direction of an opening position, in which it presents the entry section of its own seat facing the same part of the entry section of the seat of the supporting body so as to enable introduction and extraction of the engagement portion of the lock striker in/from said seats. The said fork can be turned about its own pin in order to assume the aforesaid closing position, in which a portion of the side edge of the seat intercepts the seat of the supporting body so as to block the engagement portion of the lock striker within the seats themselves.

The pawl is designed to couple by snap action with the peripheral edge of the fork in order to block the fork itself, in a releasable way, in the closing position, and is loaded by a corresponding spring in the direction of said peripheral edge.

Typically, entry of the engagement portion of the lock striker into the seat of the supporting body is guided by the walls that delimit the seat itself at the sides, the said walls presenting a profile that converges in the direction of the bottom wall.

In order to reduce the noise produced by coupling between the lock striker and the lock, there are currently adopted constructional solutions based mainly upon the use of a buffer or damper, which is typically made of rubber and is set inside the seat of the supporting body and is coupled to the bottom wall of the seat itself so as to define a damped striking arrest for the engagement portion of the lock striker.

On account of the curvilinear conformation of the engagement portion of the lock striker, distribution of the contact pressures between the external surfaces of the engagement portion and of the buffer is not uniform. In particular, the contact pressure is maximum in an area corresponding to an intermediate portion of the buffer and decreases markedly towards the opposite side edges of the latter.

Over time, this may cause tearing of the buffer, with adverse effects on retention of the lock striker and on the damping action performed by the buffer. Furthermore, this phenomenon may cause an undesired increase in play between the dimensions of the door and the corresponding opening for receiving the door, which is provided in the bodywork of the motor vehicle, with consequent generation of noise and possible rattling of the door when the vehicle is travelling.

SUMMARY OF THE INVENTION

The purpose of the present invention is to provide a lock for a door of a motor vehicle, which will enable, in a simple and inexpensive way, to reduce the noise generated by coupling between the lock itself and the corresponding lock striker.

According to the present invention, a lock is provided for a door of a motor vehicle. The lock includes a closing mechanism designed for coupling with a lock striker along a direction of relative coupling. The closing mechanism includes a supporting body having a housing seat for receiving an engagement portion of the lock striker. An elastically compliant buffer delimits the housing seat at least in the aforesaid direction of relative coupling in order to define damped arrest of the engagement portion of the lock striker. The buffer is coated on its surface, in an area of interaction with the engagement portion of the lock striker, by a rigid protective shield. The shield is fixedly secured to the buffer.

BEST MODE FOR CARRYING OUT THE INVENTION

With reference toFIG. 1, the number1designates, as a whole, a lock built according to the present invention.

The lock1is designed to be mounted on the door (not illustrated) of a motor vehicle (not illustrated) and to couple to a fixed lock striker2, which is fixed to an upright of the body of the motor vehicle (not illustrated) to provide for closing of the door. The lock striker2is illustrated in just one of its portions3that interacts with the lock, the said portion presenting a cylindrical conformation with axis A.

The lock1comprises a supporting body4having a box-like shape and designed to be rigidly fixed, in a known way, to the door of the motor vehicle and having a substantially U-shaped opening5for receiving the portion3of the lock striker2, and a closing mechanism6(illustrated with a dashed and dotted line to render visible the parts of the supporting body4underlying it), which is set inside the supporting body4and is designed to couple, via the opening5and in a way in itself known, with the portion3of the lock striker2along a direction B of relative coupling transverse to the axis A for achieving closing of the door of the vehicle.

In particular, the supporting body4comprises a pair of plates7,8made of metal material, which are substantially plane and are set facing one another and parallel to one another, and a shell9made of plastic material set between the plates7,8and defining, inside, an opening10, which communicates with the outside through the opening5and in which there is set the closing mechanism6.

The opening5is made through the plate8and the shell9of the supporting body6and defines, at one end, an entry area11for the portion3of the lock striker2. The opening5is delimited, at an end opposite to the entry area11, by a bottom wall12orthogonal to the direction B and, laterally, by a pair of walls13set transverse to the wall12. More precisely, the walls13have first plane portions14extending orthogonally from respective end edges of the bottom wall12, and second plane and oblique portions15, which diverge with respect to one another starting from the portions14and which form with the portions14respective projections16facing towards the inside, of the opening5. Consequently, the opening5has, starting from the entry area11, a section that decreases progressively towards the area of the projection16, from which it widens out sharply towards the portions14of the walls13to assume, along the portions14, a constant cross section.

The closing mechanism6comprises, in a known way, a fork20and a pawl21hinged to respective pins22,23, which extend between the plates7and8and are set on opposite sides of the opening5. The pins22,23are rigidly fixed to the plates7,8and have respective axes parallel to the axis A of the portion3of the lock striker2and orthogonal to the plates7and8.

The fork20is formed by a shaped metal plate coated with plastic material, is hinged at one of its own intermediate portions to the pin22, and has a U-shaped peripheral seat24designed for being engaged by the portion3of the lock striker2and delimited laterally by a pair of teeth25,26.

The fork20is normally maintained by a spring (not illustrated) in an opening position (not illustrated either), in which it presents its own seat24oriented on the same side as the opening5of the supporting body4so as to enable engagement and disengagement of the portion3of the lock striker2.

Under the thrust of the lock striker2and following upon slamming of the door, the fork20rotates about the axis of its own pin22from the opening position to a closing position (FIG. 1), where the portion3of the lock striker2is blocked in the seat24, and the tooth25intercepts the opening5in a known way, preventing it from coming out.

The pawl21is formed by a shaped metal plate, which is coated with plastic material and extends on the same plane of lie as the fork20and at one side of the latter. The pawl21has an L-shaped lateral projection27, which is designed for snap coupling with the tooth26of the fork20so as to block the fork20in a releasable way in the closing position.

The pawl21is pushed, in a known way, in the direction of the fork20by a cylindrical helical spring28acting against one side of the pawl21opposite to the side from which the projection27extends.

Advantageously, inside the opening5of the supporting body4, between the area of the projections16and the bottom wall12, is housed a pad or buffer30, made of elastically compliant material and defining a damped arrest for the portion3of the lock striker2so as to reduce the noise produced by the coupling between the lock striker2and the lock1.

In particular, the buffer30is formed by a substantially prismatic block or pad made of elastomeric material having an end surface31set so that it bears upon the bottom wall12of the opening5and opposite lateral surfaces32set so that they bear upon the respective walls13of the opening5.

The buffer30(seeFIG. 2) is delimited, on the opposite side of the end surface31, by an end edge33for receiving the portion3of the lock striker2, the said end edge having an arched and concave conformation.

Coupling of the buffer30with the supporting body4is obtained by coupling of a projection34, which extends in cantilever fashion from the end surface31of the buffer30with a groove or recess17having a complementary conformation made in the bottom wall12of the opening5. As may be seen fromFIG. 1, in order to ensure retention of the buffer30in the direction B, the projection34has opposite lateral edges35that are oblique and converge with respect to one another towards the end surface31.

Coupling of the buffer30with the supporting body4is obtained by coupling of a projection34, which extends in cantilever fashion from the end surface31of the buffer30with a groove or recess17having a complementary conformation made in the bottom wall12of the opening5. As may be seen fromFIG. 1, in order to ensure retention of the buffer30in the direction B, the projection34has opposite lateral edges35that are oblique and converge with respect to one another towards the end surface31.

The buffer30further has, in an intermediate position, a slot36, which is elongated in a direction transverse to the lateral walls of the opening5, the said slot36being designed to enable elastic bending of the end edge33of the buffer30during impact with the portion3of the lock striker2.

According to an important characteristic of the present invention, the end edge33of the buffer30is coated on the surface by a rigid protective shield or plate40, which has the function of enabling an even distribution of the impact load of the portion3of the lock striker2over the entire surface of the end edge33, thus eliminating any risk of tearing of the buffer30.

The shield or plate40is also U-shaped and has opposite lateral edges41folded around the buffer30. In particular, the plate40is fixedly secured to the second end33of the buffer30by forcing the opposite lateral edges41of the plate40around the buffer30. For ease of installation, the shield40can be fixedly secured to the second end33of hte buffer30prior to couping of the buffer30with the supporting body4such that the buffer30and shield40are a one-poece component.

According to a preferred embodiment of the present invention, the plate40has, in the area of interaction with the portion3of the lock striker2, a surface coating made of ceramic material with a low coefficient of friction. The said coating prevents generation, while the motor vehicle is travelling, of any squeaking deriving from the possible relative sliding between the portion3of the lock striker2and the plate40in the direction of the axis A.

Finally, it is clear that modifications and variations can be made to the lock1described and illustrated herein, without thereby departing from the sphere of protection of the present invention.