Abstract:
Vehicle door latch, in which the catch comprises a casing made of sound-proofing material, the casing containing a buffer pocket, situated behind the primary position in clockwise direction and the buffer pocket being stretched around up to the area of the primary position, forming an overtravel stop cooperating with the pawl.

Description:
CROSS-REFERENCE TO RELATED APPLICATIONS 
   This is a National Stage Application of International Patent Application No. PCT/DE 2004/000907, with an international filing date of Apr. 30, 2004, which is based on German Patent Application No. 103 20 457.1, filed May 8, 2003. The contents of both of these specifications are incorporated herein by reference. 
   BACKGROUND OF THE INVENTION 
   1. Field of the Invention 
   The invention refers to a vehicle door latch containing a locking mechanism comprising mainly a catch and pawl and a locking pin, moving into an inlet opening and interacting with the catch, with the inlet opening containing at least one soundproofing element for the locking pin. 
   2. Description of Related Art 
   A vehicle door latch of the type described above is disclosed in EP 0 336 034 A2 or WO 95/10679 A1. In the reference system of the vehicle door latch, the soundproofing element ensures that the locking pin, moving into the inlet opening and then held by the catch in its primary position, is fixed in this position with a minimum of noise. In general, a relative movement is carried out between the locking pin and the inlet opening, with the locking pin usually being fixed to the vehicle body, whilst on the other hand a vehicle door and with it the respective vehicle door latch are moved. 
   Apart from the described noise reduction of the soundproofing element, this component ensures that a respective vehicle door can be closed with excess stroke, so that the pawl engages correctly into the primary position of the catch. Such soundproofing elements have a proven record and are frequently used in practical applications. 
   We also refer to EP 1 136 640 A1, providing, however, no soundproofing element in the inlet opening for the locking pin, but instead three individual rubber buffers assigned to the catch. 
   A locking mechanism can, for instance, be electrically opened, by the pawl being lifted by a motor or another means, so that the catch is released and carries out a spring-driven rotation movement around its axis. In order to limit this rotation movement, separate stops can be provided inside the latch housing. 

   
     BRIEF DESCRIPTION OF THE DRAWINGS 
     Below, the invention is explained in detail with reference to a drawing representing only one embodiment of the invention, in which: 
       FIG. 1  shows the vehicle door latch of the invention without inlet insert with a top view of the locking mechanism and 
       FIGS. 2 and 3  show different views of the inlet insert. 
   

   BRIEF SUMMARY OF THE INVENTION 
   The invention described herein provides a vehicle door latch with a locking mechanism ( 1 ,  2 ) mainly comprising a catch ( 1 ) and pawl ( 2 ) and a locking pin ( 5 ), moving into an inlet opening ( 6 ) and interacting with catch ( 1 ), with the inlet opening ( 6 ) containing at least one soundproofing element ( 8 ) for the locking pin ( 5 ), characterized in that the soundproofing element ( 8 ) also acts as a cushion for the catch ( 1 ). 
   In certain embodiments of the invention described herein, the soundproofing element ( 8 ) restricts the opening movements of the catch ( 1 ). 
   In certain embodiments of the invention described herein, the soundproofing element ( 8 ) is designed as an L-shaped insert for a receiving groove ( 9 ). 
   In certain embodiments of the invention described herein, the long L-leg ( 8   a ) of the soundproofing element ( 8 ) is designed as a holding leg ( 8   a ) and the short L-leg ( 8   b ) of the soundproofing element ( 8 ) as a cushioning leg ( 8   b ) for the locking pin ( 5 ) and the catch ( 1 ). 
   In certain embodiments of the invention described herein, the holding leg ( 8   a ) contains recesses ( 12 ) allowing easy crosswise insertion into the receiving groove ( 9 ). 
   In certain embodiments of the invention described herein, the cushioning leg ( 8   b ) contains a locking pin stop face ( 16 ) on the inside and a catch stop face ( 10 ) on the outside. 
   In certain embodiments of the invention described herein, the inlet opening ( 6 ) and the receiving groove ( 9 ) are arranged mainly parallel to and amongst each other. 
   In certain embodiments of the invention described herein, the inlet opening ( 6 ) and the receiving groove ( 9 ) together form an inlet insert ( 7 ) for a latch housing ( 3 ). 
   In certain embodiments of the invention described herein, the cushioning leg ( 8   b ) protrudes at least partially from the inlet insert ( 7 ). 
   In certain embodiments of the invention described herein, the soundproofing element contains a temporarily closed cover for inserting, for instance, an emergency locking tool. 
   DETAILED DESCRIPTION OF THE INVENTION 
   The invention is based on the technical problem of further developing a vehicle door latch of the above type, in such a way that the design is simplified and, in particular, the number of the required components is reduced. 
   To solve this technical problem, a vehicle door latch of this type is characterized by the soundproofing element also operating as a cushion for the catch. In other words, the soundproofing element has two functions. On one hand, as a noise-reducing stop for the locking pin and, on the other hand, as the cushion for the catch. In order to restrict the rotation movement of the catch, a stop or limit stop can be provided in the back plate or latch housing. In general, the soundproofing element or the cushion for the catch can also carry out the function of a stop and restrict the opening movements of the catch. This means that the rotation movements of the catch after lifting of the pawl, as described above and regularly associated with an electrical and mechanical opening of the locking mechanism, are restricted by a separate stop or limit stop or by the soundproofing element. 
   In any case, the catch is not only fixed during an opening movement and is, so to speak positioned in an opened state, but at the same time, the cushion ensures that the catch does not move directly against a hard stop during the described opening process but that instead, its movement is cushioned. At the same time, the soundproofing element ensures that the catch positioned in its open position is acoustically uncoupled from an obligatory latch housing, so that no rattling noise can be heard. This also prevents that the electric opening or opening movements of the catch initiated in any other manner generate a noise when moving against a stop. The soundproofing element does actually prevent such stop-related noises. 
   In a proven embodiment, the soundproofing element is designed as a L-shaped insert for the inlet opening. One L-leg of the L-shaped soundproofing element may be designed as a holding leg and the other L-leg as a cushioning leg for the locking pin and the catch. The cushioning leg provides not only a stop for the locking pin but also a stop for the catch. 
   For this purpose, the inside of the cushioning leg contains a locking pin stop face and the outside a catch stop face. The locking pin stop face is located at the end of the inlet opening, whilst the catch stop face protrudes over the inlet opening on the outside. 
   In order to be able to easily position the soundproofing element opposite the inlet opening, the holding leg contains recesses, guarantying a tilt-free and easy crosswise insertion into a receiving groove. The receiving groove is arranged mainly parallel to the inlet opening. It is, in most cases, located below the inlet opening and forms together with the inlet opening an inlet insert for a latch housing. 
   This means that this inlet insert, which may be a molded plastic part, can be inserted into the latch housing, not only accommodating the locking mechanism but also the usual lever apparatus, latched to it or connected in another manner. Prior to this, the soundproofing element was inserted into the receiving groove of the inlet insert, with the recesses on the holding leg ensuring the described easy crosswise insertion. 
   The cushioning leg, on the other hand, protrudes at least partially from the inlet insert for the catch to move against with a stop, projection, etc. and receives, at the same time, the required cushioning. The invention also suggests that the soundproofing element contains a, in most cases, fitted and temporarily-closed cover for the insertion of, for instance, an emergency locking tool. The emergency locking tool (in the simplest form an ignition key) is able to move a locking lever or generally the locking lever mechanism into the “locked” position if, for instance, the central locking has failed. 
   As a result, a vehicle door latch is provided that contains a prefabricated inlet insert for the latch housing, whose soundproofing element carries out at least two functions. On one hand, the soundproofing element ensures that the locking pin meets a limit stop and that, in particular, in the primary position, the catch is not only safely positioned but also, at the same time, fixed without nearly any noise. This is because the soundproofing element is generally made of a thermoplastic plastic, in particular, polyurethane (PUR) or rubber. Shore-A hardnesses of 60 to 90 and preferably of 70, have been proven to be advantageous. 
   On the other hand, the soundproofing element with its cushioning leg protruding over the inlet insert provides the additional function of acting as a cushioning stop for the catch. For this purpose, the catch contains a rib, a projection, a journal or a similar stop, which lies against the cushioning leg upon completion of its opening movement. This causes the catch to correctly assume its open position with, at the same time, the opening movement being stopped and maintained practically without any noise, so that the vehicle door latch according to the invention produces hardly any externally audible noise or transmits structure-borne noise via the vehicle body. These are the main advantages of the invention. 
   The figures contain a vehicle door latch, showing mainly a locking mechanism  1 ,  2  comprising catch  1  and pawl  2 , which are arranged together in a latch housing or back plate  3 . As soon as the pawl  2  is lifted out, the catch  1 , as shown in  FIG. 1  turns clockwise, as indicated by the arrow, around its axis  4  out of the indicated primary position by means of a spring. At the same time, a locking pin  5 —only indicated—is released so that the respective vehicle door—not shown—can be opened in the usual manner. The lifting out of the pawl  2  can be achieved by purely mechanical means via an actuating lever mechanism—not shown—or by means of a motor, in particular an electric motor, as detailed under electric opening, described above. 
   In order to return the catch  1  to its first or primary position, the locking pin  5  in the reference system of the vehicle door latch, moves into an inlet opening  6 , shown in particular in  FIGS. 2 and 3 . This inlet opening  6  is defined by an inlet insert  7 , which preferably can be designed as a molded plastic part. The inlet insert  7  is inserted in the latch housing or the back plate  3  and can, for instance, be connected to it by latching or another means. Apart from the inlet opening  6 , the inlet insert  7  contains a receiving groove  9  for a soundproofing element  8 . 
   The soundproofing element  8  can, for instance, be made from thermoplastic plastic, according to the PUR (polyurethane) embodiment. It has an L-shaped form with a long L-leg  8   a  and a short L-leg  8   b . The long L-leg  8   a  is designed as a holding leg  8   a  and generally serves to support the locking pin  5  compared to the catch  1 . To assist this process, a spring lip  17  may be molded to the holding leg  8   a , extending from the holding leg  8   a  inwards within the inlet insert  7 . In principle, the locking pin  5  can, however, also lie directly against the short L-leg  8   b . The object of the invention naturally also covers a combined version. In one way or another, the long L-leg  8   a , the short L-leg  8   b  and, where applicable, the spring lip  17  ensure that the locking pin  5  is correctly held and guided into the inlet opening  6  with a minimum of noise. 
   The inlet opening  6  in the inlet insert  7  has a funnel or conical shape and is restricted at its end side by the short L-leg or the cushioning leg  8   b . Logically, the locking pin  5  lies against the cushioning leg  8   b  in the primary position of catch  1  shown in  FIG. 1 , said cushioning leg also restricting the movement of the locking pin  5  and providing, at the same time, a low-noise fixing in the primary position of the catch  1 . 
   The receiving groove  9  in the inlet insert  7  is also L-shaped, with its short L-leg  9   b  being open towards the top, whilst the long L-leg  9   a  of receiving groove  9  accommodates the long L-leg  8   a  or holding leg  8   a  of the soundproofing element  8 . Because of the open shape of the L-legs  9   b  of the receiving groove  9 , the short L-leg  8   b  or the cushioning leg of the soundproofing element  8  is able to protrude at least partially from the inlet insert  7 , as clearly recognizable in  FIGS. 2 and 3 . 
   This end of the cushioning legs  8   b  of the soundproofing element  8  protruding from the inlet insert  7 , defines a catch stop face  10 . As after completion of its opening movement, the catch  1  lies, preferably with a projection  11 —a molded rib  11  according to the embodiment—against the respective catch stop face  10 . In principle, the catch stop face  10  can alternatively or additionally contain a stop or limit stop  18  for the catch  1 , arranged in the latch housing or back plate  3 . This limit stop  18  restricts an overtravel movement of the catch  1 . 
   In order to be able to correctly position the long L-leg  8   a  or holding leg  8   a  of the soundproofing element  8  within the receiving groove  9 , the holding leg  8   a  contains recesses  12 , allowing easy crosswise insertion of the holding leg  8   a . Catch  1  may also contain a plastic casing, for minimizing any noise when reaching the opening position of the catch  1  shown in  FIGS. 2 and 3  and also in the primary position according to  FIG. 1 . At the same time, the plastic casing ensures that the locking pin  5  interacts with catch  1  with a minimum of friction and noise. 
   Also, a spring stop  13  on catch  1  is shown, upon which a leg spring—not expressly shown—acts, in order to initiate the described opening movement of the catch  1  in clockwise direction, as shown in  FIG. 1  and to initiate such movement with the pawl  2  lifted. 
   The projection  11  or the rib or stop rib  11  on the catch  1  has a circular arc profile and contains a rib stop face  14 , whose gradient corresponds to the inclination of the catch stop face  10  or of the cushioning leg  8   b  of the soundproofing element  8  when the catch  1  is in open position. Because the stop or the rib  11  protrudes from the catch  1 , the inlet insert  7  can be positioned in the immediate vicinity of the catch  1 , as the stop or the rib  111  on the whole finds a recess  15  at this point, represented by a circular arc in  FIG. 3  and permitting the required movements of the catch  1 . At the end side of the inlet opening  6 , a locking pin stop face  16  is shown on the inside of the inlet opening  6  on the cushioning leg  8   b.