Impact resistant vehicle door latch device

In a vehicle door comprising a vehicle door body and a vehicle door latch device adapted to latch and lock said vehicle door body in a vehicle frame, said latch device being carried within said vehicle door body, the improvement wherein said latch device comprises:

• a latch body for accommodating a latch adapted to be engaged with a striker of the vehicle frame and a ratchet to be engaged with the latch for holding the engagement between said latch and the striker;
• a door opening mechanism provided on a rear side of the latch body for releasing the ratchet from the latch;
• a locking mechanism provided on the rear side of the latch body and displaceable between a locked condition for disabling an opening operation of the door opening mechanism and an unlocked condition for enabling the opening operation of the door opening mechanism;
• a metal back plate fixed to the rear side of the latch body;
• said locking mechanism having an inner locking lever and an outer locking lever, said inner locking lever having a first base portion which is rotatably mounted to the back plate by a metal supporting shaft and a first tip portion which extends from the first base portion to an interior side of said vehicle door body and is connected to an inside lock button of said vehicle door body, said outer locking lever having a second base portion which is rotatably mounted to the back plate by the supporting shaft and a second tip portion which extends from the second base portion to an exterior side of the vehicle door body and is connected to a key cylinder of the vehicle door;
• wherein said supporting shaft has a large-diameter cylindrical part which supports the inner and outer locking levers, and a substantially annular flange which is integrally formed with the cylindrical part and has a plane surface perpendicular to an axis of the supporting shaft, said annular flange being located between the first base portion and second base portion.