In a motor-vehicle door, the lock and the latch associated therewith are generally installed at a distance from one another and, above all, at different levels. In order for the lock to be able to control operation of the latch despite this particular relative positioning, it is known to use a driving device that mechanically connects the movable part of said lock to that of said latch.
The driving device generally takes the form of a rotating coupling element whose one end is coupled with an axially rotating movable part of the lock via a universal joint-type link. The other end of the coupling element is also rotatably coupled, still by means of a universal joint link, but this time with an axially rotating movable part of the latch. The rotationally movable parts in question are usually constituted by the lock barrel and by the external control lever of the latch, respectively.
This type of arrangement nevertheless has the drawback of being extremely vulnerable to tampering. The coupling element is in fact relatively easy to access from the outside if, first, the rubber seal component between the window and the sheet metal outer panel of the door is removed and if, second, said panel is separated from said window as far as possible using an inflatable balloon, for example. It is then not difficult to make sufficient space to allow the insertion of multi-grip pliers with the aim of gripping the coupling element in order to forcibly rotate it. The universal joint is indeed held by the lock, but if a sufficiently high degree of torque is applied it is possible to break at least one component of the rotation drive train, i.e. to cause a breakage inside the lock and/or of the coupling element and/or at the interface between these two members. If a torque continues to be applied thereto via the pliers, the coupling element will actually be rotated. As the coupling element is, furthermore, still coupled with the control lever of the latch, rotation thereof will thus cause said lock to be unlocked. All that remains is then to pull the handle, and the door will open.
In order substantially to reduce the vulnerability of such a device, it is generally proposed to add a fixed cap that covers the coupling element.
Another method consists in increasing the coupling element's resistance to torque.
Unfortunately, these various solutions have the drawback of being less compact.
Thus, the technical problem to be solved by the subject of the present invention is to propose a driving device for actuating a latch via a lock, in particular for a motor-vehicle door closure system, that includes a coupling element whose ends are capable, respectively, of being rotatably coupled with a part, mounted movably in axial rotation, of the lock on the one hand and with a part, mounted movably in axial rotation, of the latch on the other, a driving device of this type making it possible to avoid the prior-art problems by offering, in particular, enhanced compactness and a substantially improved resistance to tampering.